preferably , indicators 30 and 32 , as shown in fig1 are each a tactile device which comprises an array of elongated elements . each is shown in exploded oblique detail in fig2 as three elements . each element has a long , thin shape . the shape is obtained by longitudinally slicing a cylinder in half and rounding the end - points . the flat undersurface , unseen from this perspective , is mounted on a handguide . in this arrangement , the elements are side - by - side and parallel to each other . they are spaced equally and are of equal length . a mid - element cross - section taken at line 3 -- 3 is detailed in fig3 . each element in fig3 which shows an exploded cross - sectional detail , is a half - circle - profile . left , central , and right elements 38 , 40 , and 42 are mounted on a flat surface 44 , which is the upper surface of handguide 144 in fig1 . each element has an axis that is represented in this sectional view as left , central , and right radius points 46 , 48 , and 50 . each element has the same radius 52 . such radius is measured from a radius point to the curved , exterior surface of the element . the distance between point 46 of left element 38 to a left element &# 39 ; s surface 54 is typically 3 . 2 mm or 0 . 13 inch . similarly , the distance between radius points 48 and 50 of respective central and right elements 40 and 42 to respective surfaces 56 and 58 is the same , 3 . 2 mm or 0 . 13 inch . thus , the typical diameter 60 , 62 , and 64 of each element is 6 . 4 mm or 0 . 25 inch . adjacent elements are separated by a left and right space 66 and 68 which is typically 3 . 2 mm or 0 . 13 inch each . a total cross - sectional width 70 of all three elements 38 , 40 , and 42 , including space 66 and 68 , is typically 25 . 6 mm or 1 . 00 inch . the elements of fig2 are shown in exploded , plan view in fig4 . a length 72 of each of the elements 38 , 40 , and 42 is typically 35 . 0 mm or 1 . 38 inches . each element is centered over parallel and equally - spaced axes . left element 38 is centered over a left axis 74 ; central element 40 is centered over a central axis 76 ; and right element 42 is centered over a right axis 78 . space 66 is equal to space 68 . the use of spaced , multiple elements along three axes , as seen in fig2 , and 4 , provides differentiation . it offers the pedestrian an unusual feel that is quickly identifiable from any unrelated prominent tactile feature that might be encountered on a handguide . for instance , if the elements were to be aligned abutting one another in a packed , close - together fashion , they might resemble a single raised edge and be mistaken for something else . e . g ., one might think they were an improperly disposed wad of flattened , used chewing gum . alternatively , if only one axis or element were to be used , the element might be too narrow to be easily detected . moreover , a wide version of a single element might resemble the wad of gum and not be easily distinguished . the uniqueness of the design insures against mistaken identification . there is little chance for a foreign tactile protuberance to be confused with the last - step indicator . greater detail of any one element of fig3 is shown by the enlarged , sectional view in fig6 a . this element typically has a smooth exterior surface 102 . the element &# 39 ; s composite material 104 is typically opaque black or bright yellow and consists of any of a variety of materials , preferably plastic but may also be wood or metal or a composite material . a flat base 106 of the element is coated with an adhesive 108 . the side of the adhesive which is not adjacent to base 106 is called an adhesive - mount surface 110 . surface 110 has a temporary protective covering or release sheet 112 . a full side view of the element in fig6 a , illustrating , again , smooth exterior surface 102 , is shown in fig6 b . exposed , sharp exterior edges are eliminated by way of rounding , sloping , and / or providing a radial surface to the ends of the element as evidenced by a rounded end 113 . elements , as seen in fig6 a and 6b , have a smooth exterior surface 102 and rounded ends 113 to minimize snagging of skin as well as clothing and articles that might inadvertently brush against them . flat base 106 is coated with contact adhesive 108 that is protected with release sheet 112 . after the release sheet is removed just before installation to expose the adhesive , the element is pressed into position . the release sheet may directly contact adhesive mount surface 110 as shown or it may cover but not directly contact surface 110 if it is held slightly apart by a frame , such as by a mounting template . in order to increase safety awareness and to draw public attention to indicator installations , the elements can be in high - contrast colors , such as with bright yellow alternating with black . additionally , this visual enhancement can help to supplement tactile recognition and detection when needed by staircase users who are partially sighted or capable of some sight . a variation of the last - step indicator comprises an indicator having four elements 80 , 82 , 84 , and 86 is seen in the exploded plan view of fig5 . axes 74 , 76 , and 78 and their configuration in fig5 are identical to those in fig4 . however , in contrast to the single central element in fig4 there are two central elements in fig5 a top - central element 84 and a bottom - central element 86 . an upper cross - section taken at 88 -- 88 and a lower cross - section taken at 90 -- 90 in fig5 have the identical sectional profile shown by fig3 . a tip - to - tip spacing 92 separating the adjacent ends of elements 84 and 86 is typically 7 . 9 mm or 0 . 31 inch . length 94 of left - most element 80 and right - most element 82 is typically 34 . 9 mm or 1 . 37 inches each . length 96 of element 84 and length 98 of element 86 are are also typically 34 . 9 mm or 1 . 37 inches each . total four - element configuration - length 100 is typically 77 . 7 mm or 3 . 05 inches . all axes and elements are parallel . the four - element indicator in fig5 is useful in two ways . first , it serves the purpose of indicating an upcoming last step . secondly , it is recognized as a value - added indicator , offering additional information . specifically , it is associated with the proximity of another staircase nearby to the one that is currently being exited . its positioning signifies that another set of stairs , such as by a landing , is about to be encountered . detection of the four element indicator warns the stair user of the potential danger . he or she is made cognizant that another staircase is close - by and , therefore , poses a stair - entry hazard . the recognizable pattern of the four - element indicator serves to express the additional warning . any one of the three elements from fig3 is shown in an enlarged , sectional view in fig7 a . unlike the element with smooth surface 102 in fig6 a and 6b , this element has a textured exterior surface 114 . the element in fig7 a has the same adhesive configuration and composite material options as the one illustrated and described in fig6 a . examples of the element in fig7 a are shown in full side view in fig7 b and 7c . from this orientation , these elements display examples of textured surfaces . the texture can include small nubbins , pimples , or bumps , such as a bump 116 , or a series of small surface ridges , such as a ridge 118 , that are essentially perpendicular to the element &# 39 ; s length dimension . if more hand sensitivity to the element is required , the element &# 39 ; s surface can have more texture , as seen in fig7 a , 7b , and 7c . texture includes , but is not limited to , bumps 116 and ridges 118 . elements , as shown in fig6 a and 7a with adhesive 108 , flat base 106 , and release sheet 112 , are designed for retrofit installation on existing handguides . indicators , however , can be manufactured and integrated into new handguides . in such cases , welds can be used in place of adhesive , or elements can be carved or molded into the handguide material , or elements can be anchored in any way into or onto the handguide . other features , in addition to prominent surface texture , can enhance recognition . such features can increase detection by staircase users who are partially sighted or capable of some sight . for instance , element color and light can be luminous , fluorescent , iridescent , reflective , holographic , prismatic , or self - lit ( such as with a light - emitting diode , light filament , electron - stimulated gas or plasma , or any other light or color producing mechanism ). installed indicators 30 and 32 on a staircase handguide are shown in a side view in fig8 . indicator 30 is typically installed on the handguide at a location directly above next - to - top step 34 . indicator 30 and a top last - step 120 are separated by a ( top staircase ) horizontal - space 122 . indicator 32 is typically installed on the handguide at a location directly above next - to - bottom step 36 . indicator 32 and a bottom last - step 124 are separated by a ( bottom staircase ) horizontal - space 126 . because stair users can fall at either top or bottom ends of a staircase , indicators are placed at both ends as seen in fig8 . in order to provide meaningful tactile warnings , indicators 30 and 32 are located a certain distance or horizontal - space 122 and 126 that precedes final pedestrian steps 120 and 124 respectively . typically , the indicators are located directly over next - to - top step 34 and next - to - bottom step 36 in order to provide traversing stair users with sufficient notice . the installed last - step indicator 32 in fig9 is being approached by a pedestrian during staircase descent . this oblique view illustrates a relative foot position 128 with regard to a hand position 130 prior to the pedestrian &# 39 ; s hand coming into contact with indicator 32 . a typical handguide bend 132 is located in an area beyond next - to - bottom step 36 . a pedestrian hand 133 sliding along a handguide just before encountering the last - step indicator is shown in the close - up view in fig1 . orientation of the hand illustrates , in this case , a descending movement . the hand is guided in a right - to - left , downward angle along the handguide in the direction from a high - point 134 toward a low - point 136 . a uniform handguide surface 138 is provided along a dimension 140 . last - step indicator 32 is shown just beyond location 142 . the pedestrian &# 39 ; s hand position 130 , on the handguide in fig9 is seen just before he or she reaches indicator 32 and next - to - bottom step 36 . the pedestrian , whose foot position 128 is one step above the next - to - bottom step , will reach indicator 32 the moment he or she reaches next - to - bottom step 36 . a handguide bend 132 , which is located beyond the stairs , provides no advance warning . consequently , handguide bends are of little use from a last - step safety standpoint . the pedestrian hand 133 in fig1 is seen moving right to left from high point 134 to low point 136 along the smooth , uniform handguide surface 138 . with the hand sliding along the consistent surface of the handguide , a staircase user quickly develops a familiarity with that specific surface . because the hand is accustomed to the uniform surface along most of the handguide , illustrated as dimension 140 , it is able to easily detect a dissimilarity in the surface texture . surface texture is perceived by the hand to change directly after location 142 when indicator 32 , a uniquely - styled protuberance , is touched . an indicator attached to section of pipe - style handguide 144 is shown in plan view in fig1 . the mounting orientation of the three , side - by - side elements is in a longitudinal direction that parallels the handguide . a handguide cross - section line 12a -- 12a is detailed in fig1 a . a cross - sectional detail in fig1 a shows the indicator mounted on a pipe - style handguide , which has a convex - mount - surface profile 146 . the indicator , when mounted on a handguide having a flat - mount - surface profile 148 , is shown in the sectional detail in fig1 b . the indicator , when mounted on a handguide having a concave - mount - surface profile 150 , is illustrated in the sectional detail in fig1 c . the design of the indicator facilitates installation on any handguide - profile surface . the three - axis indicator is able to accommodate various profiles , including convex , flat , and concave . the indicator ( whose length dimension parallels handguide direction ) in fig1 is shown on a small segment of pipe - style handguide . this handguide is a convex - mount surface 146 as shown in fig1 a . conversely , if an indicator were composed of a single wide - element , its wide flat base would not fully contact such a curved surface . three - axis indicators are shown accommodating other handguide surface profiles , including a flat - mount surface 148 in fig1 b and a concave - mount surface 150 in fig1 c . individually , each element has a small footprint to contact the handguide surface . collectively , however , grouped , multiple elements permit the stair user &# 39 ; s hand to perceive the many elements as a whole , covering a supposedly larger area than the actual footprint of contact . last - step indicators provide a wide - profile tactile cue yet easily conform to curved handguide profiles for effective retrofitting . a three - element configuration of the last - step indicator on a small section of handguide is shown in plan view in fig1 a . elements 38 , 40 , and 42 are aligned evenly , side - by - side . a four - element configuration of the last - step indicator on a small section of handguide is shown in plan view in fig1 b . elements 80 , 82 , 84 , and 86 illustrate two differences compared to the elements of fig1 a : ( 1 ) there are more elements in fig1 b ; ( 2 ) the arrangement of 13b elements is unique . the instances in which three - element and four - element indicators are used are illustrated in fig1 . upper and lower floor levels 152 and 154 in a theoretical two - story building are separated by a double staircase which has a single midway landing 156 . upper and lower staircase three - element indicators 158 and 160 are from the type shown in fig1 a . upper and lower staircase four - element indicators 162 and 164 are from the type shown in fig1 b . the three and four - element indicators from fig4 and 5 are shown mounted on a segment of handguide in fig1 a and 13b respectively . there are specific circumstances that dictate the prescribed use of each indicator . when descending and encountering indicator 162 on the multiple staircase shown in fig1 , a blind or visually - unable stair user could be under a false sense of security if only a single configuration of indicator ( i . e ., a three - element indicator ) were to be used universally . in such a case , after safely descending and exiting this upper staircase onto landing 156 , he or she could tragically enter the lower staircase unknowingly and fall . for this reason , it is very valuable to provide stair users with additional safety information when one staircase is in close proximity to another staircase . the four - element indicator from fig1 b serves this purpose . not only does it indicate an upcoming last step , it is recognized as a value - added indicator , offering additional information . its presence , when detected , signifies , as well as a staircase &# 39 ; s last step , that another set of stairs is about to be encountered . the recognizable pattern of the four - element indicator serves to express the additional warning . consequently , the four - element version from fig1 b is used for indicators 162 and 164 so that the presence of the adjacent staircase can be communicated . this , in turn , facilitates a safe encounter by the pedestrian . thus , it permits the stair user , who exits one staircase onto landing 156 , to be apprised , upon exiting , that there is another adjacent staircase nearby . alternatively , because no adjacent staircases lie ahead of stair users who reach levels 152 and 154 , the standard three - element version from fig1 a is used for indicators 158 and 160 . upon detection , indicators 158 and 160 simply convey the approaching end of a staircase while indicators 162 and 164 convey the approaching end of a staircase and the close proximity to the entrance to another staircase . an installation template is shown in an oblique view in fig1 . the template is a thin , single - piece , semi - rigid material , such as thermoformed - plastic . it has a flexible , flat surface 166 and several elongated dome - shaped blisters , as shown by blisters 168a , 168b , and 168c . printed , embossed , or inscribed around the sides are line , triangle , and numeric reference markings 170 , 172 , and 174 . the top surface of the installation template shows , in plan view in fig1 , flat surface 166 , three blisters 168a , 168b , and 168c , and markings 170 , 172 , and 174 . the bottom surface of the installation template is illustrated in plan view in fig1 . in order to adequately show underside details , a release sheet , which normally covers an underneath surface 176 has been removed in this fig . a retaining edge , such as edge 178 which holds element 42 within the blister recess , encircles the edge of each blister recess . a template cross - section taken at line 18a -- 18a is detailed in fig1 a . an exploded cross - sectional detail is shown in fig1 a . within template 180 , each element , including element 42 , is encased by a blister recess , such as a recess 182 of blister 168a . release sheet 112 ( which is shown as having been removed in fig1 ) covers all underneath surfaces . a template that is used for installing or mounting the elongated elements on handguides is shown in fig1 , 16 , 17 , and 18a . it is typically a thermoformed , flexible plastic part . because the template has a relatively thin dimension , surface 176 in fig1 can easily contour around or conform against any designated handguide profile . the template has a series of blisters , in this case three , each of which contains a single indicator element . to assist with accurate positioning of the indicator elements , surface 166 , in fig1 and 16 , provides line , triangle , and numeric reference markings 170 , 172 , and 174 . when an installation person views the template against the handguide front a position that is directly above the template , he or she can use these markings to easily center and align the device for precise placement on the handguide . the underside of the template in fig1 is shown with the release sheet having been removed . retaining edge 178 is of a dimension that is slightly smaller in circumference than the circumference dimension of element 42 &# 39 ; s edge . consequently , the retaining edge confines and holds the element within the blister . each of the three elements in fig1 a are contained within their respective blisters of template 180 and are encased by release sheet 112 . blister 168a contains element 42 within its own blister recess 182 . seven successive steps during indicator installation using the template are illustrated in fig1 b through 18h . a detailed progression of the installation is shown by the successive figs . sheet 112 , in fig1 b , is shown in the process of being peeled away from surface 176 . element 42 , with exposed surface 110 , is held within recess 182 by edge 178 . the template , in fig1 c , retains , with its blisters , the exposed elements which are being positioned over a mount - surface 186 . the template , in fig1 d , is shown as it contacts surface 186 . edge 178 keeps adhesive surface 110 of element 42 above surface 186 . left , central , and right dome points 188 , 190 , and 192 in fig1 e are shown flattened by a downward force against each respective element . the flat adhesive surface of each element is shown pushed down to a horizontal level that is below the elements &# 39 ; respective retaining edges , as is evidenced by element 42 having been pushed past edge 178 . adhesive surfaces of all elements , such as surface 110 , are shown in contact with mount - surface 186 . the template , in fig1 f , is shown with unflattened points 188 , 190 , and 192 and with all three elements remaining on mount surface 186 . mounted elements , after complete removal of the template , are shown in fig1 h in alignment with uniform spaces 66 and 68 . seven successive stages of an installation are seen in fig1 b through 18h as the template is prepared , positioned , compressed , and removed . template &# 34 ; preparation &# 34 ; is illustrated in fig1 b . release sheet 112 is being peeled back and away , exposing the template &# 39 ; s underneath surface 176 and adhesive mount surface 110 of element 42 . because the circumference dimension of retaining edge 178 is smaller than the circumference dimension of the element &# 39 ; s outside edge , edge 178 holds element 42 ( having the larger circumference dimension ) within blister recess 182 . the template and elements in fig1 c are shown being lowered onto designated mount surface 186 . the template , in fig1 d , is shown contacting the mount surface . because retaining edge 178 is able to hold element 42 within the blister , adhesive mount surface 110 is still suspended above mount surface 186 . this allows the template to be adjusted and positioned ( by the installer with the aid of reference markings 170 , 172 , and 174 in fig1 ) for precise placement . after positioning is finalized , pressure , such as by a hand or thumb of the installer , is exerted on left , central , and right - dome points 188 , 190 , and 192 of the blisters shown in fig1 e . this pressure causes the elements to slip past their respective retaining edges , because the template is semi - rigid and can flex . after pressure is released from the dome points , as shown in fig1 f , the elements are seen having been bonded successfully to mount surface 186 . from this point on , there is no further use for the template . template 180 in fig1 g is shown in the process of being peeled up and off of the mounted elements . it is discarded . all elements are not only mounted , they are aligned and oriented in a way that is uniform and exact . spaces 66 and 68 , shown in fig1 h , are equal and proportionate . handguide indicators and an installation device , illustrated in fig1 a through 28b , serve as alternative examples to the preferred embodiments discussed and included in fig1 through 18h . fig1 a shows a segment of handguide 144 in plan view with two side - by - side , parallel elements , of a single length 194 , whose ends align in a direction that is perpendicular to the direction of the handguide . fig1 b shows a segment of handguide 144 in plan view with three parallel , diagonally - offset elements of length 194 . fig1 c shows a segment of handguide 144 in plan view with four side - by - side , parallel elements , two with length 194 and two with a longer length 196 . examples of three alternative configurations of elongated elements are shown in fig1 a through 19c . each indicator configuration illustrates differing numbers and orientations of elements that are distinctive . although the device is shown previously as specifically arranged elements in three - dement and four - element configurations , it can include , but not be limited to , other possible arrangements of elongated elements in regards to orientation and number . for instance , as shown in fig1 a , there are only two elongated elements , of single length 194 , whose ends align in a direction that is perpendicular to the direction of the handguide . as shown in fig1 b , there are three elements of single length 194 , whose ends align in a direction that is diagonal to the direction of the handguide . as shown in fig1 c , there are four elements , two of which have a single length 194 and two of which have a longer length 196 . these three designs are meant to serve only as examples of the wide variety of possible configurations . a single , screw - type element in fig2 a illustrates in plan view a half - sphere , dome 198 . this indicator element shows a hexagonal recess 200 at the center apex . the element in fig2 a is shown in side view in fig2 b illustrating shape 198 , recess 200 , and screw 202 . although our last - step indicator uses elements that are elongated , it can include , but not be limited to , other shapes , such as a half - sphere or dome - shape . such a possible dome - shape 198 is shown in fig2 a and 20b in this particular case , the element uses screw 202 , in place of an adhesive , for securing the element onto wood or other handguide material . the element has hexagonal recess 200 to be engaged by a suitable power tool or hand tool , such as an allen wrench , that accommodates recess 200 . as the element is turned by the engaging tool , screw 202 is driven through the handguide surface into the handguide material until it finally anchors flat base 106 , of the element , securely against the exterior surface of the handguide . as opposed to a standard screwdriver slot , the less - common hexagonal recess helps dissuade vandals from tampering . however , the engaging mechanism ( e . g ., hexagonal recess 200 and its compatible engaging tool ) can be of any design for successfully screwing a threaded element to a handguide . such engaging mechanism can include any style of tool with compatible tool - receptacle , slot , opening , groove , hole , raised edge , etc . the single indicator element in fig2 a shows in sectional side view a dome - shaped push - rivet 204 . this element is suspended above a predrilled opening 206 that has been made in a thin - walled handguide 208 . a series of angled fins , such as an upper angled - fin 210 , are composed of a semi - rigid material , such as plastic , and are circumjacent to a rivet stem 212 . in fig2 b , rivet 204 is shown after insertion into opening 206 . upper fins , including fin 210 , are shown compressed against a wall surface 214 of opening 206 . lower angled - fins , such as a fin 216 , are shown in their previously extended orientation ( original position ). fin 216 is shown contacting a handguide opening - edge 218 . an alternative to the dome - shaped screw element in fig2 a and 20b is an element that is a dome - shaped push - rivet 204 , as shown in fig2 a and 21b . this style of element requires predrilled opening 206 to be made into thin - walled handguide 208 so that rivet stem 212 can be inserted . a series of angled - fins , such as upper angled - fin 210 , encircle stem 212 . the design of these fins allows them to be flexible in a limited way . these fins are able to compress upwardly against stem 212 when force is applied against the bottom surface of the fins . however , the fins are not able to flex downwardly beyond their original extended orientation . therefore , fins may compress upwardly and may decompress back to original position but may never compress downwardly beyond original position . after stem 212 of push - rivet 204 has been inserted into opening 206 in fig2 b , upper angled - fins , including fin 210 , are shown in a compression state against wall surface 214 due to the restricting diameter of opening 206 . these compressed fins provide a secure , tight &# 34 ; comfort fit &# 34 ; within opening 206 . lower fins , including lower angled - fin 216 , have been pushed down past opening wall 214 and have assumed their original , uncompressed state . since angled - fin 216 is nearest to opening - edge 218 , it contacts this edge . because fin 216 cannot compress downwardly , it locks the rivet firmly in place . fig2 a shows an element - insert in oblique view with fins , including an element - insert fin 220 , circumjacent to a central post 222 . at the top , there is a flange 224 and a snap - rivet hole 226 with a ring - shaped recess 228 . recess 228 is past of a mechanism that serves to lock a compatible , mating element into hole 226 . an element - insert cross - section taken at line 22c &# 34 ;-- 22c &# 34 ; is detailed as a middle part 22c &# 34 ; in fig2 c . element - insert fins , including fin 220 , illustrated in side view in fig2 b , encircle and are tangent to central post 222 . a top surface shows flange 224 and snap - rivet hole 226 with ring - recess 228 . three parts in sectional , side view are shown in fig2 c . a dome - shaped , snap - in element 230 with rivet stem 212 and ring - ridge 238 is shown as a top part 22c &# 39 ;. a cross - sectional detail of the element - insert taken in the direction indicated by section line 22c &# 34 ;-- 22c &# 34 ; in fig2 a is shown in fig2 c as middle part 22c &# 34 ;. this view of the element - insert shows snap - rivet hole 226 and recess 228 . thirdly , a sectional detail of a bottom part 22c &# 34 ;&# 39 ; in fig2 c shows a single opening 234 that has been drilled through handguide surface 236 . the insert or middle part 22c &# 34 ;, in cross - sectional detail in fig2 d , is shown after it is pushed fully into opening 234 of bottom part 22c &# 34 ;&# 39 ;. it also shows indicator rivet or top part 22c &# 39 ; after it is pushed fully into hole 226 of middle part 22c &# 34 ;. another version of an element that , in this case again , is dome - shaped , is shown in fig2 a , 22b , 22c , and 22d . it consists of a snap - in style element and a mating insert that receives the snap - in element . an element - insert in fig2 a shows a central post 222 . it has a series of angled fins , including fin 220 which encircle the central post . these fins have the same mechanical attributes as the fins described in fig2 a and 21b . flange 224 is a flat surface that provides a smooth contact surface for the base of the mating element . hole 226 is the receiving hole for the element &# 39 ; s rivet stem . the insert in fig2 b shows the series of angled - fins , including fin 220 , which encircle post 222 . angled - fins are able to compress , decompress , and lock into a predrilled opening in a handguide . flange 224 serves to provide a compatible flat surface of sufficient diameter that , upon installation , contacts the flat base of the mating element . hole 226 is centered at the top of the insert . ring recess 228 , along the side of the hole , serves to receive and securely hold a ring ridge that is located around the stem of a compatible , mating snap - in element . three parts are shown in fig2 c . a dome - shaped , snap - in element 230 with rivet stem 212 is shown as top part 22c &# 39 ;. ring - ridge 238 is one half ( the male half ) of the locking mechanism that holds the element and the insert together . an element - insert with snap - rivet hole 226 is shown as middle part 22c &# 34 ;. ring - shaped recess 228 is the other half ( the female half ) of the locking mechanism that holds the element and the insert together . the composite material of the element and the insert are typically a non - brittle plastic that has some capacity to expand without breaking . since the diameter of the element &# 39 ; s ring ridge is larger than the diameter of the insert &# 39 ; s snap - rivet hole , one or both components must be somewhat flexible to deform slightly during insertion . however , once the element has been forced fully into the snap - rivet hole , such as by pounding with a hammer , the ring - ridge and the ring - shaped recess mate together making removal difficult and unlikely . single opening 234 , that has been drilled through handguide surface 236 , is shown as bottom part 22c &# 34 ;&# 39 ;. the diameter of opening 234 is of a sufficient size to accommodate the diameter of the insert &# 39 ; s post and fins . all three parts of fig2 c are shown assembled in fig2 d . the element or top part 22c &# 39 ; has been fitted securely into snap - rivet hole 226 , and the insert or middle part 22c &# 34 ; has been fitted securely into opening 234 of handguide , bottom part 22c &# 34 ;&# 39 ;. the dome - shaped , expansion element 239 , shown in side view in fig2 a , is a rivet having central pull - stem 240 . the rivet is shown positioned directly above opening 206 , which is previously drilled into handguide 208 . fig2 b shows element 239 in side view after having been inserted into opening 206 . pull - stem 240 , in side view in fig2 c , is shown after upward pull - force has been applied showing an expanded rivet stem 242 against handguide opening - edge 218 . the expanded rivet , in side view in fig2 d , is shown after pull - stem 240 has been cut to a level that is flush with dome surface 246 . another variation of the indicator , in this case a rivet - style with dome shape , is illustrated in sequence of operation for installation as shown in fig2 a through 23d . shown prior to insertion , in fig2 a , is a dome - shaped , expansion element 239 , with central pull - stem 240 , positioned above predrilled opening 206 on handguide 208 . pull - stem 240 is not activated . shown in fig2 b is element 239 after its insertion into opening 206 . pull - stem 240 is still not activated . pull - stem 240 , in fig2 c , is shown after activation . an upward force has been applied to the pull - stem to cause the bottom part of the rivet stem to flare out . expanded rivet stem 242 exceeds the diameter dimension of the opening so as to contact the under surface of the handguide at handguide opening edge 218 . this contact serves to lock the element into position . the fastened element , in fig2 d , is shown after pull - stem 240 is cut flush to dome surface 246 of the element . the cutting results in a clean , cosmetic appearance because it eliminates the protruding portion of pull - stem 240 , which becomes unnecessary at this point . a thin - walled , flexible drill - bit template 248 , in side view in fig2 a , shows integral left , central , and right drill - bit guides 250 , 252 , and 254 . right guide 254 shows a drill - bit guide shaft 256 . template 248 , with guides 250 , 252 , and 254 , is shown in plan view in fig2 b . a cross - section of the drill - bit template , taken at line 24c -- 24c , is detailed in fig2 c . a cross - sectional detail in fig2 c shows template 248 with guides including guide 254 with shaft 256 . template 248 , which is shown in side view in fig2 d , is positioned onto the exterior surface of handguide 144 , which is shown in sectional detail . a drill bit 258 in shaft 256 , illustrated in side view in fig2 e , is shown after having pierced designated hole 260 in handguide 144 , which is illustrated in sectional detail . a drill - bit template , showing its use on a handguide , is illustrated in fig2 a through 24e . it is used to assist in drilling element holes in order to achieve proper , consistent element alignment during installation . these element holes are drilled for elements whose designs require holes as part of their fastening system . flexible drill - template 248 is shown in side view in fig2 a . each drill - bit guide , 250 , 252 , and 254 , has a guide shaft . shaft 256 , of guide 254 , has a diameter that is similar to that of a proposed drill - bit , which is used to make a designated hole . the shaft diameter is also similar to the diameter of a chosen element &# 39 ; s rivet stem , which will be inserted into the designated hole upon installation . because each guide is permanently attached and anchored to template 248 , orientation and alignment of guide shafts ( as well as spacing between the shafts ) permit the installer to drill the proper pattern of holes on a consistent basis . this insures that the drilled holes are accurate and at the optimum angle and that the pattern of inserted elements is uniform among all installations . flexible drill - template 248 is shown in plan view in fig2 b . guides 250 , 252 , and 254 are offset , in other words , not parallel , to one another due to the curvature of the template . this offset allows a drill - bit , that is introduced through each guide shaft , to be capable of drilling an opening or hole in a direction that is exactly perpendicular to the surface of the handguide . therefore , the shaft direction of each shaft faces exactly 90 ° to the drill surface or handguide surface . since template 248 conforms to the curved handguide surface , the adjoining guides with their respective shafts , always properly orient the drill - bit so as to keep the drill - bit from boring into the curved handguide surface at an incorrect angle . template 248 , in fig2 c , shows a cut - away perspective of fig2 a . the guide shafts and template are shown as a single , molded part . template 248 , in fig2 d , is shown as it conforms to the profile of handguide 144 . the template , which is typically composed of a soft or non - brittle plastic , is flexible enough so that it is able to conform to the profile shape and size of most pipe - style handguides . if the diameter of the handguide or the radius of its surface is larger or smaller than that which is shown , the template can assume the differing dimension due to the built - in flexion of the template . drill - bit 258 , in fig2 e with the template mounted on handguide 144 , is shown guided by shaft 256 and having just penetrated the handguide at designated hole 260 . after two more holes are made using the other two guides , the template is removed and the appropriate indicator elements are inserted . an integrated indicator in fig2 a shows in an exploded , plan view a solid , flexible , flat membrane 262 with integrated domes ( elements ), including a dome 264 . a cross - section of the integrated indicator taken at line 25b -- 25b is detailed in fig2 b . an integrated indicator in fig2 b is a cross - sectional detail showing membrane 262 , dome 264 , a contact - adhesive layer 266 , and a protective peel - off liner 268 . membrane 262 , shown in an oblique view in fig2 c , is attached to the surface of a small section of handguide 144 . an indicator , shown in fig2 a through 25c , illustrates a flexible , one - piece , thin membrane having properly - spaced , integrated domes ( elements ). the entire piece is secured to a handguide using an adhesive . a solid , flexible , flat membrane 262 , shown in fig2 a , is typically composed of a soft or non - brittle plastic . this allows the membrane to conform to curved surfaces easily . the membrane has a series , in this case three , integrated domes , such as dome 264 . the domes can be composed of any material that is identical , similar , or different to that of the membrane itself . dome 264 can be more easily seen from the sectional view in fig2 b . it rises substantially above the surface of membrane 262 . contact - adhesive layer 266 is exposed when protective peel - off liner 268 is removed . this allows the adhesive on the bottom surface of the membrane to be applied to any designated surface on a handguide . this system can eliminate the need for an installation mounting template or for a drill - bit template since the elements ( domes ) are integrated with the membrane as one unit . fig2 c shows membrane 262 , with integrated domes , as it is typically mounted . membrane 262 is illustrated as it conforms to the curved surface on segment of handguide 144 . shown on handguide 144 in plan view in fig2 a are three half - sphere , dome - shaped elements , in a linear alignment 270 that is perpendicular to the direction of the handguide . shown on handguide 144 in plan view in fig2 b are four half - sphere , dome - shaped elements , in alignment 270 that runs parallel to the direction of the handguide . shown on handguide 144 in plan view in fig2 c are four half - sphere , dome - shaped elements , in alignment 270 that is diagonally - offset to the direction of the handguide . although foregoing variations of the device have been shown as three - element , dome - shaped element indicators , it can include , but not be limited to , other possible arrangements of elements in regards to orientation and number . three examples of alternate configurations of dome - shaped elements are shown in fig2 a through 26c . each indicator configuration illustrates a specific number of elements in an orientation that is distinctive . therefore , elements , in any number and of any shape or design , can be arranged in a pattern that is deemed to be meaningful and of prominence to the staircase user . for instance , three elements , in fig2 a , are shown in linear alignment 270 in a direction that is perpendicular to the direction of the handguide . four elements , in fig2 b , are shown in linear alignment 270 in a direction that is parallel to the direction of the handguide . four elements , in fig2 c , are shown in linear alignment 270 in a direction that is diagonal to the direction of the handguide . a wedge - shaped indicator and timing block is shown in side view in fig2 a &# 39 ;. a wedge - shaped indicator and timing block is shown in oblique view in fig2 a &# 34 ;. a wedge - shaped indicator and timing block is shown in frontal view in fig2 a &# 34 ;&# 39 ;. a block - mount surface 272 is typically mounted against an escalator handguide support or handguide frame . when the block is mounted , a leading surface 274 is oriented in a way that faces toward approaching escalator pedestrians . when the block is mounted , a tactile edge 276 is oriented in a way that faces toward the near - by end of an escalator . an escalator handguide , shown in plan view in fig2 b , is illustrated with the wedge - shaped indicator and timing block mounted on a stationary handguide frame 278 which is directly under a moving handguide 280 . this illustrates positioning of surface 272 , surface 274 , and edge 276 . an indicator and timing block mounted on an escalator handguide frame is shown in oblique , side view in fig2 c . frame 278 , with handguide 280 , is shown with the mounted indicator and timing block illustrating surface 274 and edge 276 . a cross - section of the escalator taken at line 27d -- 27d is detailed in fig2 d . a sectional detail of an escalator in fig2 d shows frame 278 , with handguide 280 , and a rear view perspective of the indicator illustrating edge 276 and surface 272 . the indicator and timing block are shown mounted on the handguide frame surface that is exterior to a pedestrian step 282 . the end of an escalator is shown in plan view in fig2 e . protruding out from underneath both handguides , including handguide 280 , is a set of three indicator and timing blocks mounted on the exterior surface of each handguide frame . illustrated on the right handguide frame is a block called a primary - encounter - block 284 ; a block called a first cadence - block 286 ; and a block called a second cadence - block 288 . a non - moving step , which serves as part of the level floor surface , is shown as termination point 292 . the end of an escalator is shown in side view in fig2 f . it illustrates one set of three indicator and timing blocks mounted on frame 278 , which is transparent , directly underneath handguide 280 . rising escalator steps , including step 290 , terminate from view at termination point 292 . horizontal distance spacing between blocks 284 and 286 is called an &# 34 ; interval number one &# 34 ; 294 . horizontal distance spacing between blocks 286 and 288 is called an &# 34 ; interval number two &# 34 ; 296 . horizontal distance spacing between block 288 and point 292 is called an &# 34 ; interval for stepping &# 34 ; 298 . each indicator and timing block evidences edge 276 . a variation of the last - step indicator for escalators is illustrated in fig2 a &# 39 ; through 27f . because escalator handguides move concurrently with steps and pedestrians , previously illustrated and described last - step indicators for stationary handguides , when placed on moving handguides , are of no value . a hand holds an escalator handguide at only one location and does not slide along the surface of the handguide . consequently , in order for a hand , which grasps a moving handguide , to encounter an indicator , the indicator - attachment for escalators must be on a non - moving part . this non - moving part is the guide - frame upon which the handguide slides . a last - step indicator for escalators is therefore attached just below the handguide on the handguide frame so that a pedestrian &# 39 ; s fingers brush against the indicator when encountered . because hand - placement on an escalator handguide can vary , it is necessary to use an indicator that is substantially more prominent than standard staircase versions discussed and explained previously . this is why a wedge - shaped indicator block is used . however , even with a single indicator block present , a non - sighted or partially - sighted escalator - user can have difficulty knowing exactly when to step off the escalator . timing , therefore , presents an additional problem . for instance , escalator speed can vary . most importantly , no time - frame reference exists . even after detecting one indicator block , an escalator - user can still step too soon or too late and , as a consequence , fall . therefore , it is necessary to establish a system that generates a frame - of - reference for timing . using indicator blocks in series provides the needed cadence to precisely alert the user as to when to step . therefore , last - step indicators for escalators are called timing blocks as well as indicator blocks . the wedge - shaped indicator and timing block is shown in fig2 a &# 39 ;, 27a &# 34 ;, and 27a &# 34 ;&# 39 ;. leading surface 274 is the location where a pedestrian &# 39 ; s fingers initially contact the block . as opposed to a blunt , flat , perpendicular surface that can harshly strike oncoming hands , the incline surface of the wedge - shape prevents the block from snagging or injuring fingers . after fingers traverse the sloped surface of the wedge , they fall or snap back over tactile edge 276 towards the guide frame . fingers snap back because they have a natural tendency to curl around the handguide . edge 276 , therefore , serves as a point - of - reference , since traversing fingers find it to be distinct and noticeable . block - mount surface 272 is the surface that is attached to the guide frame . it is typically attached with an adhesive but can be bolted , screwed , riveted or mechanically fastened or integrated in any number of ways . a segment of escalator handguide and guide frame , with a mounted indicator and timing block , is shown in fig2 b . stationary handguide frame 278 , which is directly under moving handguide 280 , is the non - moving part upon which block - mount surface 272 is attached . as an escalator user approaches the end of an escalator , his or her fingers , which are curled around the moving handguide , safely contact leading edge 274 , traverse the slope of the wedge , encounter edge 276 , and finally snap back toward the surface of handguide frame 278 . this moment of going over the edge and &# 34 ; snapping back &# 34 ; serves as a point - of - reference . fig2 c shows an indicator and timing block mounted on guide frame 278 below a section of handguide 280 . as one &# 39 ; s hand travels from left to right , fingers encounter surface 274 . after sliding over and past edge 276 , fingers , having a natural tendency to curl around the handguide , snap back toward the surface of the handguide frame . handguide 280 , frame 278 , and pedestrian step 282 are seen in fig2 d . surface 272 of the indicator block is shown attached to the outside of frame 278 . indicator blocks are typically mounted on the exterior side of the frame , opposite the side facing the escalator steps , such as step 282 . this preferred mounting position is due to the fact that fingers , rather than a thumb , are more likely to curl around underneath the handguide to contact the indicator . edge 276 is seen from the rear perspective . the end of an escalator , shown in fig2 e , illustrates in plan view the relative positioning of multiple indicator and timing blocks . the direction of pedestrian travel is toward the escalator end shown . stationary handguide frame 278 is seen directly under moving handguide 280 . as the pedestrian approaches the end of the escalator , he or she encounters and manually senses the first block called primary - encounter - block 284 . at this point the pedestrian is made aware that an upcoming last step is near - by . within a brief moment , his or her hand senses first cadence - block 286 . between blocks 284 and 286 , a time - interval frame - of - reference is established . when his or her hand encounters second cadence - block 288 , a second and identical time - interval , between blocks 286 and 288 , is realized . having sensed and &# 34 ; learned &# 34 ; equal time - intervals &# 34 ; one &# 34 ; and &# 34 ; two &# 34 ;, the pedestrian is able to discern and anticipate that the time - interval between block 288 and termination point 292 is precisely one more time - interval , identical to the first and second intervals . the cadence , therefore , that is established by intervals &# 34 ; one &# 34 ; and &# 34 ; two &# 34 ;, allow the pedestrian to know exactly that he or she must step off the escalator on &# 34 ; three &# 34 ;, the end of the third and final time - interval . determination for stepping off the escalator , therefore , relies not only on detecting a series of blocks but on realizing and understanding the time - intervals between the blocks . the end of an escalator , shown in fig2 f , illustrates in side view the relative positioning of multiple indicator and timing blocks . as in fig2 e , the direction of pedestrian travel in fig2 f is toward the escalator end shown . stationary handguide frame 278 is seen directly under moving handguide 280 . as the pedestrian approaches the end of the escalator , he or she encounters and manually senses block 284 . the identifying point - of - reference is established when his or her fingers snap over block 284 at edge 276 . at this point , the pedestrian is made aware of an upcoming last step . soon , his or her fingers sense block 286 and identify the second point - of - reference at edge 276 of block 286 . between blocks 284 and 286 , a time - interval frame - of - reference is established . this is the time that transpires between the horizontal distance traveled between both blocks . it is called &# 34 ; interval number one &# 34 ; 294 . when the moving hand encounters block 288 , identifying it at its edge 276 , a second and identical time - interval , between blocks 286 and 288 , is realized . it is called &# 34 ; interval number two &# 34 ; 296 . having sensed equal time - intervals &# 34 ; one &# 34 ; and &# 34 ; two &# 34 ;, the pedestrian is able to discern that the &# 34 ; interval for stepping &# 34 ; 298 between block 288 and termination point 292 is precisely one more identical time - interval . as the interval for stepping is completed , the pedestrian steps off escalator step 290 onto the floor or landing at termination point 292 . therefore , the pedestrian , without the need of any vision , exits from the escalator safely . although last - step indicators have been described as hand - tactile devices , indicators can function in such a way as to arouse another sense , namely , the auditory sense . fig2 a and 28b show one possible way an audio / last - step indicator may exist and function . an audio - style last - step indicator 300 is shown in fig2 a , a simplified diagram . it is composed of a power source 304 that is labeled &# 34 ; ps &# 34 ;, a signal generator or processor 306 that is labeled &# 34 ; cpu &# 34 ;, and a speaker 308 that is labeled &# 34 ; s &# 34 ;. an external part , called an external pressure switch 302 , is shown wire - connected to indicator 300 . power source 304 is shown as a direct current battery , a remote or independent source of power . however , power source 304 can also be a system , with or without a direct current transformer , that uses alternating current power , a system that connects directly to a building &# 39 ; s conventional electrical lines . processor 306 functions when switch 302 is activated causing a discernable change of value in the movement of electrons in the connections between various components . when activated , processor 306 uses electrical power to produce a response that is transferred to speaker 308 which in turn projects it as a distinctive , audible signal . a staircase , shown in side view in fig2 b , illustrates indicator 300 mounted directly below and beside switch 302 which has been positioned on next - to - bottom step 36 . audio - style last - step indicator 300 , shown in fig2 a , is made up of several components . such components are shown in a generalized way for simplicity . power source 304 provides the necessary electrical current . processor 306 receives electrical input , processes it , and generates a response to a speaker . speaker 308 converts this response to a recognizable message or tone . switch 302 is step - activated by a pedestrian just before the stair user reaches a last step . when installed , as shown in fig2 b , switch 302 is mounted directly on a next - to - bottom ( or next - to - top ) step . when the pressure switch is stepped - on , the electrical circuit is activated . this allows the power source of indicator 300 to activate processor 306 . processor 306 , in turn , sends a response to the speaker which produces a recognizable warning tone or message . when the tone or message occurs , the pedestrian hears the notice of being on the next - to - bottom ( or next - to - top ) step with one last step ahead . the stair user , now cognizant , safely encounters the last step . accordingly , the reader will see that last - step indicators of this invention provide a measure of great personal safety . staircase pedestrians , who , for any reason , are visually unable to discern a staircase &# 39 ; s last step , now have an important navigational aid at their disposal . when traversing a set of stairs , they can manually detect a last - step indicator , which serves as an important alerting cue . indicators provide precise notification to stair users approaching the final step . when a staircase pedestrian &# 39 ; s hand detects and recognizes the tactile indicator , it conveys that travel direction is about to shift abruptly . for the blind , the visually impaired , or the visually compromised , indicators become a manual &# 34 ; guiding light &# 34 ;. the last - step indicator provides a unique , prominent tactile surface . its profile is unobtrusive . the size , shape , spacing , surface - style , rounded ends , configuration , and orientation of the elements insures ease of recognition as well as longevity and comfort in use . coloration and lighting of elements heightens general public awareness . it also helps attract visual attention should the pedestrian in need have some visual acuity at the time . textured exterior surfaces on the elements , when incorporated , enable a pedestrian &# 39 ; s sensory ability to be enhanced . standardized positioning of indicators prior to last steps insures that staircase users have sufficient time to detect , recognize , and respond . a special version of the indicator , the four - element configuration , offers an additional advantage . as well as offering last - step identification , it provides more safety information . it notifies that the beginning of another staircase is nearby . this helps prevent stair - entry accidents . the peel - and - stick mounting adhesive on the indicators flat , mount surface provides convenience for the installer . the installation mounting template provides a simple method for consistent and precise installation of indicators . when the template is used for installation , elements are maintained in proper orientation and spacing . it speeds the process for installing multiple elements . while our above description contains many specificities , these should not be construed as limitations on the scope of the invention , but rather as an exemplification of one preferred embodiment thereof . many other variations are possible . for example : the indicators can have a subtly , moderately , or radically different appearance , shape , size , style , and configuration to the ones described and illustrated . rather than being protuberances , they can be depressions , grooves , holes , channels , etc . in the handguide . the indicators may be manufactured or integrated into new handguides by railing manufacturers . in such a case , indicators can be carved , welded , molded , etc . as well as attached with adhesive . in such cases , indicators may be of the same material and color as that of the handguide itself . the indicators may be screwed , riveted , nailed , bolted , etc . to the handguide . in such cases , the heads of the screws , rivets , nails , bolts , etc . themselves can serve as the indicators . an installation handtool that serves as a screwing , riveting , pounding , bolting , etc . device can be employed . the indicators may be placed on the stairway wall instead of on the handguide . because escalators present a different circumstance with last - step safety , an escalator version of the indicator incorporates several wedge - shaped indicator and timing blocks . located just under the moving handguide , these blocks are attached to the stationary guide frame . escalator - user fingers contact the blocks and feel these equally - spaced indicators in succession . encountering the blocks establishes a cadence in the pedestrian &# 39 ; s mind , i . e ., &# 34 ; 1 &# 34 ;, &# 34 ; 2 &# 34 ;, &# 34 ; 3 - step &# 34 ;. therefore , these indicators , as well as being a tactile cue , serve as a timing mechanism . they tell the escalator user exactly when to step onto the approaching floor or landing . the indicators may trigger one of the other non - visual / non - tactile human senses . specifically , an audible message or sound can be designed to occur when the staircase user nears the final step . in this case , an indicator can be triggered by a pedestrian contacting a pressure switch mounted directly on a next - to - bottom ( or next - to - top ) step or onto the handguide itself directly above such step . therefore , such an indicator can be activated by foot contact or by hand pressure . other variations of the indicator may include ones that are enabled by way of radar , infrared or microwave radiation , that utilize properties of or that are sensitive to heat or motion , that are photo - cell sensitive , that are logic related , that are foot - tactile / hand - tactile or that are a combination of these . accordingly , the scope of the invention should be determined , not by the embodiments illustrated , but by the appended claims and their legal equivalents .
a device of any material , shape , size , texture , style , color , configuration , and orientation that is affixed , secured , or is an integral part to a staircase handguide , to a handguide support or frame , or to a sidewall . the device provides anyone , ascending or descending the stairs , with a tactile cue that indicates the pedestrian &# 39 ; s approach to a final step in a series of steps . a pedestrian senses the tactile indicator to determine when he or she is at the last step so as to change accordingly his or her walking or motion . this safety indicator is intended for the public at large . a pedestrian without sight , with impaired or limited sight , or with compromised sight can negotiate stairs with greatly increased safety , speed , and confidence .