referring first to fig2 a fruit coring system 31 comprises a cylindrical member 33 extending from a first end 37 , attached to a handle 35 , to an opposite second end 51 which forms a leading cutting edge or cylindrical blade 43 . the taper 41 of this blade 43 is depicted in exaggerated fashion . planar blade surfaces 45 , which are largely parallel to the longitudinal axis 47 of cylindrical compression member 33 , are formed by cuts 39 made in the sides of the cylindrical compression member 33 and folding the cut portions inward . the cylindrical blade 43 is used to slice a cylindrical volume enclosing the core of a fruit . if it is desired to retain a floor of fruit below an extracted fruit core , then the cylindrical compression member is inserted so as to avoid penetrating the bottom of the fruit . when the cylindrical compression member 33 is inserted to the desired depth in the fruit , it is rotated so that the planar blade surfaces 45 will shear the sliced core from the fruit . the handle 35 may be integral with the first end 37 or made fast with the first end 37 by the use of a conventional attachment mechanism . e . g ., a press - fit , an adhesive , rivets , welding , etc . and defines a pair of opposed projections 49 which permit ease of manual use . also depicted is a thumb hole , or perforation 51 for hanging the coring system on a hook when not in use . the appropriate use of the coring system 31 for removal of a fruit core is illustrated with reference to fig3 a , showing a sequence of steps associated with the coring process . first , the coring system 31 is oriented in axial alignment with the core of the fruit . subsequently , it is inserted downward into the fruit to a desired depth , thereby slicing a cylindrical surface interior to the fruit . it is then rotated so that the fruit core is sheared from the fruit . as will be described below , the cylindrical compression member 33 is designed so that as the cylindrical compression member is withdrawn from the fruit , the core will be retained therein . the coring system 31 can be immediately used to core another fruit and the previously retained core will be ejected from cylindrical compression member 33 by the subsequent core as depicted in fig3 b . fig3 c is an exploded diagram of the results of the coring process . a fruit 77 , such as an apple for example , is shown with a cored volume 75 . the extracted core 79 exhibits slits 73 resulting from incisions by the planar blades 81 of the coring system 71 . variations in the geometry of the cylindrical blade 43 of fig2 are shown in fig4 a , 4b , 5a , and 5b . in fig4 a , the blade 95 at the end of cylindrical compression member 97 shows serrations 93 that are an alternative to a uniform , flat - edged cylindrical blade . fig4 b is a pictorial view of a cylindrical compression member 101 exhibiting a cylindrical blade 103 that has two scalloped edges 107 and 109 that form pronouncements 105 along the edges for the purpose of readily puncturing the skin of a fruit or vegetable . other blade contours , besides scallops , may be used to achieve the pronouncements and are within the scope of this disclosure . the cross - sectional view of a portion of cylindrical compression member 33 of fig2 , depicting various taper geometries for the cylindrical blade is provided in fig5 a and 5b . in fig5 a , a section 117 of the cylindrical compression member adjacent the cylindrical blade 111 is shown with both exterior and interior tapered surfaces , 115 and 113 , respectively . in the cross section , the exterior tapered surface 113 originates at point 118 and terminates at point 119 . the interior tapered surface 115 originates at point 116 and terminates at point 114 . the flat - edged cylindrical blade is formed by surfaces 113 , 115 , and flat end surface 112 . in fig5 b , a section 137 of the cylindrical blade is shown with a tapered interior surface 133 and an untapered exterior surface 135 . in cross - section , surface 133 is inclined relative to surface 135 by an angle that is preferably about 15 degrees . the interior tapered surface originates at point 136 and terminates at point 134 . in this case , the flat - edged cylindrical blade is formed by surfaces 133 , 135 , and flat end surface 138 . once the fruit core is sliced and sheared from the fruit , it remains to extract it from the fruit ; the core must be retained in the cylindrical compression member 33 of fig2 when the coring device is removed from the fruit . in order for this to happen , the sliced core must undergo adequate compression to facilitate its retention in cylindrical compression member 33 . this is achieved by proper design of the coring device as depicted in fig6 . the cross - sectional diagram depicts the cylindrical compression member 163 and the tapered circular blade 169 . the difference between the inner diameter 167 of the cylindrical compression member 163 at the edge of the blade 169 and the inner diameter 170 of the cylindrical compression member 163 at the origin 168 of the taper causes the fruit core 161 in the region 165 to be compressed as the cylindrical compression member 163 is advanced into the fruit . the reduction in the inner diameter of the cylindrical compression member 163 will lead to a pressure increase of the fruit against the inner wall of the cylindrical compression member as the fruit is compressed in accordance with the bulk modulus of the apple tissue . once the apple core is sheared free of the apple and the cylindrical compression member is retracted from the fruit , the core tends to remain in place in the apple given atmospheric pressure operating against the partial vacuum associated with retraction of the core . counteracting this atmospheric force is the friction force of the apple core against the inner wall of the cylindrical compression member 163 . this friction force is proportional to the interior surface area of the cylindrical compression member 163 , which in turn is proportional to the length of the cylindrical compression member 163 . hence , for a given length of cylindrical compression member 163 , there is a threshold change in the inner diameter of the cylindrical compression member 163 that will permit the friction force to overcome the atmospheric force and allow the core to be removed from the apple upon retraction of the cylindrical compression 163 member from the fruit . also , for a given length of the cylindrical compression member 163 , there is an upper bound on the change in inner diameter of the cylindrical compression member 163 that will permit ease of removal of the core from the cylindrical compression member 163 once fully retracted from the fruit . in summary , the change in the inner diameter of the cylindrical compression member 163 must be great enough to extract the core from the fruit , but not so great as to make it difficult to extract the core from the coring device . the bulk modulus , k , of a solid ( in the case of apple tissue , for example ) is a measure of the amount of pressure δp required to obtain a certain fractional compression δv / v where v is the initial volume . in the case of a cylinder , the fractional volume change is equal to the fractional diameter change where d is the diameter and δd is the change in diameter of the cylinder . hence , the associated pressure is f c = δp *( area of cylinder wall )= kδd / d *( π d 2 / 4 )* l = π ( dδdl )/ 4 where σ f is the coefficient of friction between apple and cylinder wall . the force countering this friction force is the difference between atmospheric force on the cross - sectional area of the cylinder and the partial vacuum that forms upon retraction of the core . for the core to be removed from the apple against a perfect vacuum , the friction force associated with the core against the cylinder surface must be greater than the atmospheric force , f atm , tending to keep the core in place . f atm = p atm *( cross - sectional area of cylinder )= 14 . 7 psi *( π d 2 / 4 ) however , it is the case that the sliced core in the apple does not maintain a perfect vacuum when retracted with the coring tool and hence , the percentage of atmospheric force in action is considerably less than 100 %. with reference to fig2 , preferred dimensions for the length of the cylindrical compression member 33 from the cutting edge 41 to the proximate surface of the handle 35 is about 1 . 7 inches and the inside diameter of the cylindrical compression member 33 is about 1 . 0 inch . there are a number of variables that affect the optimality of the amount of taper of the cylindrical compression member 33 . these include a ) the anisotropy of the bulk modulus of the apple tissue , b ) variation in the bulk modulus of apple tissue with type of apple and water content , c ) inhomogeneity of the apple core , d ) variation in the coefficient of friction between apple and cylinder surface , and e ) the selected length of the cylinder . in the face of these variables , it has been determined that the appropriate change in inner diameter of the cylindrical compression member 163 ( associated with blade taper ) to achieve the aforementioned core extraction is in the range of 0 . 020 to 0 . 070 inches for a diameter of one inch . for larger diameter cylindrical compression members , this corresponds to between 2 and 7 percent of the diameter . as depicted in fig5 a and 5b , there are two geometry options for the cutting edge 41 of fig2 , dual or single taper . each surface exhibits a taper angle relative to the longitudinal axis of the cylindrical compression member ; the associated taper angles need not be the same in the case of the dual tapered blade of fig5 a . however , it must be emphasized that it is the interior tapered surface that must adequately change the inner diameter of the cylindrical compression member to achieve adequate compression of the fruit ( or vegetable ) core . various blade taper angles may be used ; a convenient angle for the single taper blade is about 15 degrees relative to the longitudinal axis of the cylindrical compression member . the flat end surface ( 112 and 138 in fig5 a and 5b , respectively ) of the cylindrical blade should be approximately 0 . 005 inches , or so , in order to limit blade sharpness and thereby prevent inadvertent cutting of the hand when the coring device is in manual use . as previously mentioned , there can be different modes of use of the coring system . in some applications , it is desirable to remove the entire core as depicted in the cross - sectional diagram of fig7 a showing the fruit 215 with an evacuated core volume 217 . alternatively , as shown in fig7 b , a fruit 211 can have the core removed while permitting an evacuated core volume 213 that exhibits a floor within the fruit . various embodiments of the coring system permit achieving both modes of coring . one embodiment uses cylindrical compression members of differing lengths as shown in fig7 c and 7d that can be interchanged with the handle 201 shown in fig7 e . the long cylindrical compression member 191 of fig7 c exhibits the previously disclosed cylindrical blade 193 and planar blade surfaces 195 . cylindrical compression member 191 represents a length sufficient to completely core the fruit as shown in fig7 a . the shorter cylindrical compression member 199 of fig7 c represents a length that will core the fruit while retaining a floor below the cored volume as shown in fig7 b . another embodiment that achieves the same objectives comprises the inclusion of standoff collars placed around the cylindrical compression member in proximity of the coring system handle . in fig8 a , the coring system 239 is shown with a relatively tall collar 241 that results in a coring volume 243 enclosed by a floor . in contrast , the short collar 233 used with coring system 231 of fig8 b results in complete coring of the fruit with an open coring volume 235 . alternatively , to achieve different coring depths , the handle can be made to be repositioned along the length of the cylindrical compression member by threading or other means well known in the prior art such as a spring - loaded button on the handle that can be inserted into holes the cylindrical compression member 33 of fig2 can assume different cross - sectional shapes with a variety of planar blade geometries as depicted in fig9 a through 9d . these include the compression member with rounded square cross - section 261 of fig9 a and 9b with planar blades 263 , hexagonal cross - section 267 of fig9 c with planar blades 269 , and the octagonal cross - section 271 of fig9 d with planar blades 273 . fig9 e depicts a circular cross section 275 with a v - shaped blade 279 , the planes of which are parallel to the longitudinal axis of the cylindrical compression member . resection of portions of the cylindrical compression member are anticipated as in fig1 , which shows a coring system 291 with a portion of the cylindrical compression member surface in the form of legs 295 supporting a circular blade 297 and planar blade 299 by attachment through a ring 301 to handle 293 . in a preferred embodiment of the coring system shown in fig1 a and 11b , the wall of the cylindrical compression member 327 is cut at a plurality of locations circumferentially about the cylindrical blade 325 . these cut portions of the wall are folded inward to the cylindrical compression member 321 to form planar blade surfaces that are substantially parallel to the longitudinal axis of the cylindrical compression member 321 . in fig1 a , planar blade surfaces 323 are shown that result from cuts that are anti - symmetric about the longitudinal axis of cylindrical compression member 321 . the planar blade surfaces 327 result from cuts that are symmetric about the longitudinal axis of cylindrical compression member 321 . both approaches to forming the planar blades result in the cross - sectional geometry of fig1 c . other means of forming planar blades interior to the cylindrical compression member include attachment of preformed blades to the cylinder by methods well known in the prior art including brazing , riveting of blade flanges , etc . fig1 d depicts a cylindrical compression member 335 exhibiting four planar blade surfaces 337 ; the cross - sectional view 339 is provided in fig1 e . other interior blade formats are possible that will achieve shearing of the core from the fruit . a first example includes a planar blade 353 extending the full diameter of the cylindrical compression member in the coring system 351 of fig1 . a second example is that of a wire 359 affixed to the cylindrical compression member of the coring device 357 of fig1 . multiple planar blade geometries exploit the use of various numbers of such blades 373 as shown in fig1 a and 14b . the actual shapes of the planar blades can be polygonal , as exemplified by the triangular blades 393 of fig1 a or have a curvilinear perimeter as in the case of the blades 397 depicted in fig1 b . fig1 illustrates a coring system 421 with planar blades 423 oriented at an angle with respect to the longitudinal axis of the cylindrical compression member . the length of the planar blades can be short as previously depicted or can run the full length of the cylindrical compression member and shown by the rectangular planar blades 443 of fig1 . an intersecting cross geometry for the planar blades is provided in fig1 . herein , the blades 463 are shown press fit into slots 465 in the cylindrical compression member 461 , but could be attached by any number of previously discussed means . subsequent to insertion of the coring system into a fruit and rotation of the system to shear the core , when the system is removed from the fruit , there is often a partial vacuum associated with its removal . this vacuum can be mitigated by air channels shown in either fig1 a or 19b . in fig1 a , an air channel is formed by a slit 493 formed in the wall of cylindrical compression member 491 . in fig1 b , an alternative means of forming an air channel is a depression or groove 497 in the wall of cylindrical compression member 495 . various core alignment subsystems are illustrated in fig2 through 24 . in fig2 a , the alignment subsystem 527 comprises a solid cylinder 529 of diameter slightly less than the inside diameter of the cylindrical compression member , with planar slots 531 parallel to the longitudinal axis of cylinder 529 extending the full length of cylinder 529 . additionally , a metal pin 533 protrudes from cylinder 529 along the cylinder longitudinal axis . the pin 533 is inserted into the core axis of the fruit until the cylinder 529 rests against the fruit . then , the cylindrical compression member 521 of the coring system is lowered onto cylinder 529 with its planar blades 523 inserted into and passing through the slots 531 of cylinder 529 . in this way , the coring system is aligned with the core of the fruit as the coring process proceeds and the rotation of the planar cutting means is unhindered by the presence of the cylinder 529 . the geometry of the core alignment subsystem depicted in fig2 b is an adaptation of that shown in fig2 a to facilitate its unibody construction and manufacture from plastic . the cylinder 541 exhibits the same planar slots 539 , but in lieu of a metal pin has a plastic pin supported by plastic fins 545 which are tapered so as to not interfere with the motion of the planar blades . fig2 c depicts another alignment approach in which a hollow cylinder 553 with a cap 559 is shown with a pin 557 attached to the cap 559 ; the pin is coaxial with the cylinder 553 . the open edge of the cylinder 553 constitutes a cylindrical blade so that when the pin is inserted into the fruit along the core axis and the cylinder 553 is advanced , the cylindrical blade cuts a guide incision into the fruit . upon removal of this alignment subsystem from the fruit , the cylindrical compression member of the coring system can be introduced along this guide incision insuring alignment of the coring system with the fruit core . the sequence of steps required to core fruit using the alignment subsystem of fig2 a is depicted in fig2 a . first the pin of the alignment subsystem is inserted into the fruit along the axis of its core ; the pin is advanced until the slotted cylinder rests against the fruit . subsequently , the coring system is lowered onto the slotted cylinder with the planar blades advancing through the slots . once the cylindrical compression member is advanced to the desired depth , it is rotated by torque on the handle in order to shear the core from the fruit . fig2 b illustrates the result of this coring process with the fruit 565 having an evacuated core volume 567 . the slotted cylinder 555 with pin 563 holds the sliced fruit core 557 showing incisions 561 produced by the planar blades of the coring system 551 . in another embodiment of the alignment subsystem shown in fig2 a and 22b includes an alignment pin 593 that is affixed to the center of the cylindrical cap 595 and is largely coincident with the longitudinal axis of the cylindrical compression member 591 when the lip 585 of cylindrical cap 595 is inserted into the cylindrical compression member 591 . when the cap 595 is attached to the cylindrical compression member 591 and the alignment pin 593 is inserted along the core axis of the fruit , this alignment subsystem permits direct alignment of the coring system with the core axis of the fruit . in yet another embodiment of an alignment subsystem , fig2 shows an alignment pin 625 that is coaxial with the longitudinal axis of the cylindrical compression member 621 and is affixed by means 627 to crossed planar blade 623 . in a final embodiment of an alignment subsystem , a caliper - like mechanism can be used with different fruit sizes . in fig2 the mechanism is shown having two parts or arms 653 and 655 that are slidably attached . arm 655 has a key 659 that slides into slot or keyway 661 in arm 653 ; this permits caliper - like sliding motion without rotation . the protrusion 661 at the end of arm 653 is positioned at a core indentation on one end of the fruit 663 . the cylindrical section 657 at the end of arm 655 has a radius slightly larger than that of the cylindrical compression member 665 . the cylindrical section is centered above a core indentation at the other end of the fruit and the two arms 653 and 655 are slid together so that the fruit rests between the protrusion 661 and the cylindrical section 657 . then the cylindrical compression member 665 is brought into conformal contact with the cylindrical section 657 and advanced into the fruit .
a fruit and vegetable coring system comprises a tube in the form of a cylinder exhibiting a cutting edge on one end and attachment to a handle at the other end . this cylindrical blade is used to make a cylindrical incision about the core of a fruit and potentially slice through the entire depth of the fruit . in certain cooking applications , it is desirable to remove the core of the fruit , and not slice through the entire depth of the fruit , but retain a floor below the core for the retention of cooking stuffs . to make provision for this application , some form of planar blade is made part of the interior of the cylinder in the proximity of the cylindrical blade for the purpose of shearing the fruit core and freeing it from the fruit upon rotation of the cylinder about its longitudinal axis once inserted in the fruit . an alternative to the planar blade is the inclusion of a wire blade attached across the diameter of the cylinder in the proximity of the cylindrical blade . the change in the inner diameter of the cylinder due to the interior taper of the cylinder associated with the blade is disclosed to be sufficient to compress the fruit core and thereby retain it in the cylinder for removal from the fruit . provision is made for standoff collars placed along the cylinder near the handle attachment to adjust the coring depth of the cutting . additionally , various alignment mechanisms are included in embodiments of the system to provide alignment of the coring cylinder with the core of the fruit .