other objects and advantages of this invention will become more apparent from a study of the description of the drawings given above and from the additional description given below . the main objective of the present invention is to contribute to a sport of ice boarding . examples of the preferred embodiments of this invention are shown in fig1 to 6 discussed above . the notation of right side , left side , front , and back or rear of an ice skateboard refer in this specification to the respective sides of the board as would be viewed by a person ice boarding on it . for illustration , the front sides of the ice skateboards of fig1 , and 4 are their top parts shown in these figures . the preferred embodiments of this invention shown in fig1 to 3 are variations on standard skateboards where the wheels of a skateboard can be disassembled and blades can be assembled in place of the wheels , and the process of replacing wheels by blades can be reversed . alternatively , as will become clear from the discussion below , an ice skateboard of the type shown in these figures can be made to stand alone , not convertible into a skateboard . the basic components of an ice skateboard of fig1 to 3 are ( i ) deck or board , ( ii ) two trucks , ( iii ) blades ( also wheels to replace blades for convertible constructs ), and ( iv ) mounting hardware . the word truck as used here and in the claims is not to be confused with motor trucks , has the same significance as for skateboards , and refers to the structure below the deck or board that holds the blades or wheels . fig1 shows the first preferred embodiment of this invention to be a variation of a standard skateboard comprised of ( i ) a deck 1 , ( ii ) two trucks 2 mounted on the deck , ( iii ) a sample of auxiliary parts such as a tail skid plate 4 , the rails slider bars 41 , and the nose guard 42 , ( iv ) two blades 3 and four wheels that can be used interchangeably ( the wheels and associated hardware are not shown since these belong to the prior art ), and ( v ) mounting hardware . each hanger ( see 25 in fig3 described below ) or top part of a truck has two approximately one - inch long ( this dimension can be changed ) bolt - like extensions 9 to form external parts and sides of an axle for the truck used normally for assembling ( hanging ) the wheels of a skateboard . the two trucks in fig1 and 2 are mounted in such a way that their respective axles are parallel to each other in their rest positions . here the four wheels are disassembled and replaced by two blades . this figure shows how a blade is assembled to the structure . the blade has a circular hole and a slit having the same width as the circular hole and essentially the same width as the bolt - like extension 9 to the hanger of a truck . the reason for the slit is to allow for variations in possible distances between trucks and for possible use and application of a given blade structure to different skateboards . the blade 3 is assembled as shown in fig1 by inserting around the bolt - like end 9 an inner cup washer 23 ( this inner cup washer can be eliminated ), an inner cushion or bushing 24 , the hole or slit of the blade 3 , an outer cushion or bushing 24 , an outer cup washer 23 , and a tension nut 29 . the tension nut can be tightened to an appropriate desired torque . fig2 illustrates two distinct variations to the ice skateboard of fig1 . in the first variation , the blade 6 and its associated blade base 61 in fig2 are to be omitted and essentially each blade 3 of fig1 is replaced here by two smaller blades 5 , one corresponding to each truck ( in other words the construction here is achieved from a standard skateboard by replacing each of the four wheels of the skateboard by a separate blade 5 ). the second variation to the ice skateboard of fig1 is obtained from the first by adding two blades , like the blade 6 shown in fig2 one on the left as shown and one on the right ( the one on the right is not shown for clarity of the illustrations ). the additional blades 6 are fixed in place and provide both added stability , and the ability to turn while more weight is being exerted on one side of the deck of an ice skateboard . normally , the additional blades 6 are elevated and touch the ground ( icy surface ) one at a time and only as a result of weight being exerted on one side of the deck . the auxiliary blades 6 can be made to rotate slightly as is described in connection with fig6 below . each of the front or back pairs of blades 5 associated with a given truck 2 should have identical shapes , but the different pairs may or may not have the same shape . fig3 shows various component parts of a truck 2 of fig1 and 2 which is used to interchangeably support wheels or blades . this figure also shows how the truck is assembled . part of a blade 5 is shown in this figure and this part is to be viewed as being either part of a blade 5 of fig2 or part of a blade 3 of fig1 . a truck is typically assembled from the following : ( i ) a riser pad 20 typically made of hard plastic , and a base plate 21 which has the structure shown . a bolt 22 with a square or hexagonal head passes though the base plate 21 and the arrangement is such that when the bolt is fully inserted in the plate &# 39 ; s inner side , the head of the bolt is held firmly in place in such a way as to prevent rotation of the bolt . the plate also has a cylindrical indentation 28 which can accommodate a cushion pad 27 and a pivot part 26 of the hanger 25 described below . the base plate and riser pad are secured in place to the bottom side of the deck 1 by screws and tension nuts as is indicated in fig1 and 2 . the base plate and riser pad can also be combined into a single component part which can be made of metal or other hard material . ( ii ) a hanger 25 having a part which functions as a double cup washer with a slit inside it ; the slit is intended to accommodate the bolt 22 but is sufficiently wider than the bolt to make it possible to move the hanger slightly relative to the bolt . the hanger 25 has a pivot 26 and a bolt - like axle 9 to hold blades or wheels . the rest of a truck is assembled as shown in fig3 by inserting around the bolt 22 an inner cup washer 23 ( this inner cup washer can be eliminated ), an inner cushion or bushing 24 , the hold or slit of the hanger 25 ; the pivot part 26 of the hander is inserted in the cushion pad 27 which is further inserted in the cylindrical indentation 28 of the base plate 21 . also inserted around the bolt 22 above the hanger 25 are an outer cushion or bushing 24 , an outer cup washer 23 , and a tension nut 29 . the tension nut can be tightened to an appropriate desired torque . the sizes of some of the component parts in the various figures are exaggerated for ease of illustration . comparison of the bolt - like ends 9 of the axle of the hangers in fig1 and 3 shows a modification in fig3 desirable for the preferred embodiment of fig2 . here , the inner part of the bolt - like ends 9 of the axle is modified to have a square or hexagonal part . the corresponding inner cup washer 23 and inner cushion 24 of fig3 would have corresponding square or hexagonal holes in place of the circular holes , the axle 9 would have to be made a little longer in this case in order to accommodate an inner cup washer 23 and / or an inner cushion 24 before the wheels , if a person is to be able to convert the ice skateboard to a standard skateboard on wheels . the blades 5 of fig2 can be assembled to the trucks as is described above in connection with the blades of fig1 . in this case , the tension nut has to be screwed tight enough to prevent a blade 5 from rotating if weight is exerted at the front or the back of a deck to achieve certain maneuvers . three preferred new arrangements are ( a ) to have a pair of blades 5 fixed permanently ( soldered together or manufactured as a unit ) to each hanger 25 , ( b ) to have the end 9 of the axle 25 modified as shown in fig3 and in this case to have a corresponding square or hexagonal hole in the blade 5 ; the square or hexagonal hole of the blade 5 , with two ( preferrably spring lock ) washers around it , are inserted around the modified part of the axle 9 and a tension bolt is screwed to hold the blade 5 in place and prevent the blade from rotating relative to the hanger 25 , and ( c ) to carge or make indentations , for example where the very small plus sign is marked on the hanger adjacent to the axle part 9 of fig1 ; in this case , the washer and the blade would have corresponding protrusions so as to prevent the blade 5 from turning relative to the hanger . fig4 is a perspective view of an alternative design of an ice skateboard where three blades are attached to a deck or board in the same manner as a blade is attached to a shoe or boot of an ice skate . each blade here is shown to have three bases 61 to support it . the exact number m of blade bases 61 to support any blade of the present invention , need not be three ; m can be one or more , though two or three ( m = 2 or m = 3 ) are to be preferred . the middle blade 8 in fig4 is bigger and higher than the other two blades 7 and is intended to be the only blade which is always in contact with the ice or icy surface . this middle blade 8 can be removed , to result in a two - blade ice skateboard where the blades 7 are assembled parallel to each other . in the embodiment of three blades , the blades 7 may be assembled parallel to blade 8 , or possibly with a very small angle relative to blade 8 . as a result , when a person ice boarding leans to one side of the deck so that one of the blades 7 comes in contact with the ground together with blade 8 , the slight angle between the blades 7 and 8 will cause the ice skateboard to rotate . the relative angle between blades 7 and 8 can be fixed or the arrangement described below in connection with fig6 can be adapted to blades 7 to make it possible to select any of a range of reasonable angles . fig4 also shows an alternative design of the tail skid plate 4 . the double lines shown indicate indentations , the intended arrangement being similar to the bottom of a boot or the threads of snow tires to provide improved braking on icy surfaces . clearly , the modified skid plate 4 can also be used for other embodiments and also for a standard skateboard on wheels . fig5 shows an alternative design of the ice skateboard of fig4 with only one blade 8 attached to the underside of the deck . part or all of the top face of the deck is intended to be coverd by a grip tape . the top surface of the tape is rough , like durable coarse sand paper , and provides a non - skid surface for standing on the deck . for the ice skateboards of the present invention , it is desirable to develop newer grip tape with a much coarser granulated surface . altneratively , the top surface could be designed to have rubber - like threads , typically 1 / 8 to 1 / 4 inches thick , such as is used at the bottom of some boots to provide extra grip for added safety in ice boarding . the lines marked on the face of the deck 1 in fig1 are intended to indicate the presence of grip tape with lines standing for possible locations of indentations . fig6 shows a redesign of the blade base part 61 of the blade 6 of fig2 ; the redesign is intended to also apply to a modification of the blades 7 of fig4 . here the blade 6 is permanently fixed to two base plates 611 perpendicular to it . one of the base plates 611 has a circular hole and a slit in the form of an arc of a circle around the center of the first circular hole . the second plate 611 has two slits in the form of arcs of circles around the center of the first circular hole . the marks adjacent to one of the slits is a scale intended to aid in the proper positioning of pairs of corresponding blades such as 6 or 7 . base plates 62 with two bolts fixed to each are screwed or nailed to the bottom side of deck 1 . the assembly can now be achieved by inserting washers 612 ( preferably spring lock type ), the hole and slits of 611 , and tension nuts ( 29 of fig1 and 3 ) or wing nuts 613 in the order shown in fig6 . a desired orientation of the blade 6 or 7 can be selected and the nut tightened to secure this assembly . other modifications of this configuration , such as would be obvious to a person skilled in the art can be adopted to make it possible to vary the relative orientation of the blades 6 and 7 of fig2 and 4 with three blade bases . while we have illustrated and described several embodiments of our invention , it will be understood that these are by way of illustration only and that various changes , extensions and modifications may be contemplated in this invention and within the scope of the following claims .
an ice skateboard has front and rear trucks with horizontal axles attached thereto for pivotal steering movement of the axles in response to tilting of the skateboard . each of the horizontal axles has a pair of runner blades attached thereto . an auxiliary blade assembly is attached to each side of the skateboard between the front and rear trucks and in tandem with the runner blades attached to the axles . each of the auxilary blade assemblies include a mounting arrangement which permits pivotal movement of the auxiliary blade relative to the longitudinal axis of the skateboard .