US3841005A

US3841005A - Metatarsal pad mounting for weight distributing shoe shank

Info

Publication number: US3841005A
Application number: US00402032A
Authority: US
Inventors: I Cox
Original assignee: Individual
Current assignee: Individual
Priority date: 1973-10-01
Filing date: 1973-10-01
Publication date: 1974-10-15
Anticipated expiration: 1991-10-15

Abstract

A spring steel shoe shank interposed between the inner and outer sole of a shoe, which shank has a metatarsal pad mounted thereon to overlie and extend both forwardly and rearwardly beyond a transversely elongated forward metatarsal arch supporting portion of the shank. The shank has an intermediate portion of reduced width and a rear portion wider at its maximum width adjacent its forward end than said intermediate portion. The rear portion inclines gradually upwardly transversely toward the inner edge of the shank. The shank has a rectangular transversely extending slot in the forward transversely elongated portion and the metatarsal pad has a rectangular transversely extending rib closely fitting the slot to hold the metatarsal pad against shifting relative to the shank. The intermediate portion of the shank may have a longitudinal stiffening rib that extends into the forward and rear shank portions.

Description

United States Patent 1 [111 3,841,005

Cox Oct. 15, 1974 METATARSAL IAll) MOUNTING FOR WEIGHT DISTRIBUTING SHOE SHANK Primary Examiner-Patrick D. Lawson [57] ABSTRACT A spring steel shoe shank interposed between the inner and outer sole of a shoe, which shank has a metatarsal pad mounted thereon to overlie and extend both forwardly and rearwardly beyond a transversely elongated forward metatarsal arch supporting portion of the shank. The shank has an intermediate portion of reduced width and a rear portion wider at its maxi mum width adjacent its forward end than said intermediate portion. The rear portion inclines gradually upwardly transversely toward the inner edge of the shank. The shank has a rectangular transversely extending slot in the forward transversely elongated portion and the metatarsal pad has a rectangular transversely extending rib closely fitting the slot to hold the metatarsal pad against shifting relative to the shank. The intermediate portion of the shank may have a longitudinal stiffening rib that extends into the forward and rear shank portions.

12 Claims, 9 Drawing; Figures METATARSAL PAD MOUNTING FOR WEIGHT DISTRIBUTING SHOE SHANK My invention relates to weight distributing shoe shanks of tempered steel that are provided with a metatarsal pad. The present invention is an improvement over that disclosed in my US. Pat. No. 2,811,790 patented Nov. 5, 1957 on Weight Distributing Shoe Shank.

My aforesaid patent had for its purpose to provide a shoe shank, built into a shoe between the outer and inner sole, that controls the bone structure of the foot so as to distribute the weight of the body on the foot structure in the way that it would be naturally supported, if the normal foot were in engagement with the ground, or some other supporting surface, without being encased in a shoe. When the normal foot that is not encased in a shoe starts into forward motion the weight of the body is first thrown on the heel bone or foot forwardly of the heel onto the outer longitudinal arch and finally on the ball of the foot or metatarsal arch. Because shoes have heels thereon this normal action does not ordinarily occur and the outer longitudinal arch of the foot is put under a strain which produces weakness thereof and malalignment of the arch bones, and further causes the longitudinal arch of the foot to weaken and the foot to roll inwardly or pronate, throwing the inner edge portion of the foot into a lower than normal position. Because the foot structure is not in normal position the two lower leg bones are thrown into a twisted or unnatural position, which causes the legs to appear to be knockkneed.

The purpose of my shoe shank disclosed in my US. Pat. No. 2,811,791 is to control or support the bone structure of the foot to produce a normal or natural weight balancing. Since the heel bone or oscalcis is the largest bone of the foot, it is necessary that it be held in its correct position to avoid its twisting, rotating or pronating. This is accomplished in my patented shoe shank by providing means for elevating the inner forward position of the heel of the foot so as to roll the weight to the outer side of the foot or to the outer longitudinal arch. A longitudinal arch supporting portion is provided in my patented shoe shank adjacent the outer side of the insole between the forward end of the heel portion of the shank and the forward metatarsal arch or ball supporting portion of the shank.

The shank disclosed in my US. Pat. No. 2,811,791 is provided with a transversely elongated forward metatarsal arch supporting portion, that extends from the forward end of the longitudinal arch supporting portion under all of the bones of the metatarsal arch structure, and is domed upwardly from adjacent the side edges and forward and rear edges thereof to a central point.

The present invention utilizes the basic structure of the shank disclosed in my US. Pat. No. 2,811,791 to control and support the bone structure of the foot to produce a normal weight bearing including the support of the bones of the metatarsal arch structure in their ears that flatly engage the insole above the shoe heel, but inclines upwardly transversely toward the inner side edge thereof, thus throwing the weight at the heel of the foot toward the outside of the foot and toward 5 the outer longitudinal arch. Said shoe shank is of such a structure that the longitudinal arch supporting portion thereof, being located along the outer side of the insole, does not restrict the muscle functions or purpose of the inner longitudinal arch, allowing it to perform its intended function of acting as a spring or shock absorber for thebody.

It has been found that there are many foot conditions, usually resulting from improper support of the body weight by the bones of the foot, that make it desirable to raise the second, third and fourth metatarsal arch bones higher relative to the first and fifth bones of the metatarsal arch than can be accomplished by a shank structure such as that disclosed, in my US. Pat. No. 2,811,791. To provide such a raised position for the second, third and fourth metatarsal arch bones I provide a metatarsal pad in combination with my shoe shank which provides such a raised position for said second, third and fourth metatarsal bones without interfering in any respect with the functions of providing normal and natural weight balancing of the shank disclosed in said patent.

In order to have such a metatarsal pad operate properly in relation to the metatarsal arch of the foot it must be held in the proper position with respect to the bones of the metatarsal arch and the spring steel shank. I accomplish this by providing the spring steel shoe shank of the character above described with a metatarsal pad that is mounted on the forward metatarsal arch supporting portion of the shank and providing said transversely elongated forward metatarsal arch supporting portion of the shank and the metatarsal pad with interengaging means for holding the pad in proper position I with respect to the transverse arch supporting portion of the shank. The means that is provided for this purpose is of such a character that it prevents any shifting of the pad relative to the shank or twisting thereof out of position relative to the shank by providing a transversely extending rectangular slot in the forward transversely elongated shank portion and a rectangular transversely extending rib on the metatarsal pad closely fitting in the slot. The pad is preferably so formed that it tapers toward the edges thereof from the midportion thereof and has such an area that it extends both forwardly and rearwardly beyond the forward transversely elongated shank portion, the extending portions being in the tapering portion of the pad. Since the shank has a predetermined fixed position in respect to both the insole and outsole of the shoe, the metatarsal pad will have a fixed position, which is the most desirable position for such a pad, with respect to the insole of the shoe and thus with respect to the: bones of the foot of the wearer of a shoe that has my patented steel shank that is provided with the metatarsal pad, incorporated therein.

Other objects and advantages of my invention will appear as the description of the drawings proceeds. I desire to have it understood, however, that I do not intend to limit myself to the particular details shown or described except as defined in the claims.

IN THE DRAWINGS:

FIG. 1 is a bottom plan view of a shoe, showing my improved shank and metatarsal pad thereon, mounted in position in the shoe in dotted outline.

FIG. 2 is a fragmentary enlarged vertical sectional view taken on the line 2-2 of FIG. 1, the shoe upper being broken away.

FIG. 3 is an enlarged fragmentary sectional view taken on the line 33 of FIG. 1.

FIG. 4 is a diagrammatic view showing the bones of the foot in dotted outline and the outline of the shoe, my weight distributing shank and metatarsal pad in full lines in relation to the foot bone structure.

FIG. 5 is a bottom plan view of the metatarsal pad detached.

FIG. 6 is a similar view partly broken away of my shoe shank to which the metatarsal pad is to be applied.

FIG. 7 is a fragmentary vertical sectional view taken on the line 77 of FIG. 1 through the insole, outsole and the spring steel shank.

FIG. 8 is a section taken on the line 88 of FIG. 5, and FIG. 9 is a section taken on the line 99 of FIG. 5.

Referring in detail to the drawings, my improved shoe shank comprises a forward metatarsal arch supporting portion 10, an intermediate longitudinal arch supporting portion 11, and a rear portion 12. Said rear portion 12 comprises rearwardly extending attaching ears l3 and 14, the ear 13 being longer than the ear l4 and extending rearwardly beyond the rear end edge of the ear 14, the ears being spaced to provide an opening or cutout portion 15 for the nailing of a rubber heel to the insole between said ears.

The rear portion 12 gradually widens toward its junction with the longitudinal arch supporting portion 11. The outer marginal edge 16 of my shank extends substantially parallel of the outer edge of the outsole and insole, the outsole being indicated by the numeral 17 in FIGS. 2, 3 and 7. The rear portion 12 inclines upwardly transversely from a point substantially at the transverse middle of the rear portion in alignment with the cutout portion 15 to the junction 18 thereof, with the longitudinal arch supporting portion 11, the inclined portion being indicated in FIG. 7 by the numeral 19. Thus the junction 18 of the longitudinal arch supporting portion 11 with the rear portion 12 is elevated about one-fourth of an inch higher than the outer edge portion 20 thereof. The ears l3 and 14, however, are flat and engage the outsole l7 flatly, as well as the insole 21.

The longitudinal arch supporting portion 11 of said shoe shank has a slightly concavely curved inner edge 22 and an outer longitudinal edge 23 which is very slightly concavely curved so as to extend substantially parallel to and near the outer edge portion of the outsole. Thus the major portion of the longitudinal arch supporting portion 11 of my shoe shank lies on the outer side of the centerline of the shoe, the only portion thereof that lies inwardly of said centerline being the gradually widening portion that joins it with the rear portion 12. If found desirable, the longitudinal arch supporting portion may be stiffened by providing a rib 24 by means of a currugation therein which has a forward curved end portion 25 extending into the forward transverse metatarsal arch supporting portion 10, and a pair of transversely spaced portions 26 and 27 at the rear end thereof extending a short distance into the rear portion 12.

The forward metatarsal supporting portion 10 extends transversely the full width of the metatarsal arch structure of the foot underlying all the bones of the metatarsal arch shown in FIG. 4. It is of a transversely elongated substantially elliptical character having a convexly curved inner end edge portion 28 and joins with the outer edge 23 of the longitudinal arch supporting member 11 in a smooth convex curve 29 and with the inner edge 22 of said longitudinal arch supporting member in a smooth concave curve 30. Said metatarsal arch supporting portion 10 is of a concave-convex character, being domed upward or curved upwardly from all the side edges thereof toward the center thereof, the domed up portion being indicated generally by the numeral 31. Said domed portion curves upwardly from the inner and outer edges thereof toward the middle thereof, as shown in FIG. 2, and from the forward and rear edges thereof, as shown in FIG. 3. Preferably the portion 10' is raised about one-sixteenth of an inch adjacent the marginal edges thereof, and to about three-sixteenth of an inch at its highest elevation at the center of the domed portion 31 of the forward transverse metatarsal arch supporting portion 10.

The forward transverse metatarsal arch supporting portion 10 is provided, at its center at the highest elevation of said domed portion, with a transversely extending slot 32 which has straight parallel side walls 33 and straight parallel end walls 34 that extend perpendicular to sidewalls 33. A metatarsal pad 35 is mounted on the spring steel shoe shank on the forward transverse metatarsal arch supporting portion 10 thereof, being made of a molded plastic material which is slightly yieldable so as to have a cushioning action, and has integrally formed thereon a rib 36 projecting downwardly from the bottom face of said pad, said rib 36 having straight parallel sidewalls 33 and straight parallel end walls 34' extending perpendicularly to the walls 33'. Said rib is of the same size as the slot 32, having the same width and length, and fitting in the slot 32 closely.

The pad 35 has an approximately oval body portion which has a blunt forward end portion 37 and a rearwardly extending portion 38 which gradually tapers in width and thickness rearwardly from substantially the maximum transverse diameter of said pad. The maximum transverse diameter of the pad is positioned over the transversely elongated forward portion 10 of the shank and the rib 36 on said pad lies substantially on the maximum transverse diameter of the pad. The body portion of the pad has tapering marginal portions around the entire periphery of said body portion, the tapering edge portions being indicated in FIGS. 2, 3, 8 and 9 by the numeral 39. Except for the rib 36 the bottom face 40 of the pad, before assembly with the shank, is flat, while the top surface of the pad curves gradually both transversely and longitudinally of the pad from the maximum thickness 41 thereof, having a rather sharply curved end portion 42 on the blunt forward end thereof and a gradually downwardly inclining top wall 43 on the portion thereof extending rearwardly from the portion of maximum thickness of said pad to the thin tapered peripheral edge portion 39 at the rear end thereof. The pad also has the top surface thereof curved downwardly transversely, as shown at 44 in FIG. 9, from the midportion of maximum thickness thereof to the peripheral edge 39.

A metatarsal pad is thus provided that has a blunt forward end 37 which extends forwardly beyond the transversely elongated portion of the shank and a portion 38 that gradually tapers in width and thickness extending rearwardly from the portion of maximum thickness and maximum transverse diameter of said pad to the rear edge portion thereof. The portion 38 extends rearwardly beyond the transversely elongated portion 10 of the shank and overlies the extreme forward end of the longitudinal arch supporting portion of the shank. The pad is thus spaced forwardly substantially the length of said intermediate longitudinal arch supporting portion 11 from the rear portion of the shank. This spaces the transversely inclined forward end of the rear portion of the shank a substantial distance from the metatarsal pad 35 so that the shank will not have its function of throwing the weight on the heel of the foot toward the outside of the foot interfered with by the provision of the metatarsal pad. Preferably a wedge shaped filler member is placed on the outsole and secured thereto before placing the shank in position. The filler member is located under the upwardly inclined portion 19 of the rear portion 12 of the shank.

The metatarsal pad 35 is positioned under the second, third and fourth bones of the metatarsal arch to raise and support the same in a normal position.

- What I claim is:

l. The combination with a spring steel shoe shank mounted between the inner and outer shoe sole of a metatarsal pad mounted on said shank, said shank having a transversely elongated forward portion, an intermediate longitudinal arch supporting portion and a rear portion, said pad overlying said transversely elongated forward portion and extending both forwardly and rearwardly beyond said forward portion, and interfitting means on said pad and said forward portion of said shank to hold said pad against shifting relative to said shank.

2. The combination claimed in claim 1 in which said interfitting means comprises a rib on said pad fitting in a slot in said shank.

3. The combination claimed in claim 2 in which said rib and slot are rectangular and extend transversely of said pad and shank respectively.

4. The combination claimed in claim 1 in which said pad has a body portion tapering in thickness toward the marginal edges thereof and said tapering marginal portions extend both forwardly and rearwardly beyond said forward transversely elongated shank portion.

5. The combination claimed in claim 1 in which said shank has a rear portion inclined gradually upwardly toward the inside of said shank spaced from said pad, said pad has an approximately oval body portion the maximum transverse diameter of which is positioned over said transversely elongated forward portion of said shank, has a blunt forward end extending forwardly beyond said transversely elongated portion of said shank and a portion gradually tapering rearwardly in width and thickness extending rearwardly beyond said transversely elongated portion of said shank, said gradually tapering rearwardly extending portion of said pad ex tending over the forward end of said longitudinal arch supporting portion in forwardly spaced relation to said rear portion of said shank.

6. The combination with a spring steel shoe shank mounted between the inner and outer shoe sole of a metatarsal pad mounted on said shank, said shank having a transversely elongated forward portion, an intermediate longitudinal arch supporting portion and a rear portion, said pad overlying said transversely elongated forward portion and interfitting means on said pad and said forward portion of said shank to hold said pad against shifting relative to said shank, said pad having an approximately oval body portion the maximum transverse diameter of which is positioned over said transversely elongated forward portion of said shank. 7. The combination claimed in claim 6 in which said pad has a blunt forward end extending forwardly beyond said transversely elongated portion of said shank.

8. The combination claimed in claim 6 in which said pad has a blunt forward end extending forwardly beyond said transversely elongated portion of said shank and a portion gradually tapering rearwardly in width and thickness extending rearwardly beyond said transversely elongated portion of said shank.

9. The combination claimed in claim 6 in which said pad has a blunt forward end extending forwardly beyond said transversely elongated portion of said shank and a portion gradually tapering rearwardly in width and thickness extending rearwardly beyond said transversely elongated portion of said shank, said gradually tapering rearwardly extending portion of said pad extending over the forward end of said longitudinal arch supporting portion.

10. The combination claimed in. claim 6 in which said body portion of said pad tapers in. thickness toward the marginal edges thereof and said tapering marginal portions extend both forwardly and rearwardly beyond said forward transversely elongated shank portion.

11. The combination claimed in claim 10 in which said pad has a blunt forward end extending forwardly beyond said transversely elongated portion of said shank.

12. The combination claimed in claim 10 in which said pad has a blunt forward end extending forwardly beyond said transversely elongated portion of said shank and a portion gradually tapering rearwardly in width extending rearwardly beyond said transversely elongated portion of said shank.

Claims

1. The combination with a spring steel shoe shank mounted between the inner and outer shoe sole of a metatarsal pad mounted on said shank, said shank having a transversely elongated forward portion, an intermediate longitudinal arch supporting portion and a rear portion, said pad overlying said transversely elongated forward portion and extending both forwardly and rearwardly beyond said forward portion, and inter-fitting means on said pad and said forward portion of said shank to hold said pad against shifting relative to said shank.

5. The combination claimed in claim 1 in which said shank has a rear portion inclined gradually upwardly toward the inside of said shank spaced from said pad, said pad has an approximately oval body portion the maximum transverse diameter of which is positioned over said transversely elongated forward portion of said shank, has a blunt forward end extending forwardly beyond said transversely elongated portion of said shank and a portion gradually tapering rearwardly in width and thickness extending rearwardly beyond said transversely elongated portion of said shank, said gradually tapering rearwardly extending portion of said pad extending over the forward end of said longitudinal arch supporting portion in forwardly spaced relation to said rear portion of said shank.

6. The combination with a spring steel shoe shank mounted between the inner and outer shoe sole of a metatarsal pad mounted on said shank, said shank having a transversely elongated forward portion, an intermediate longitudinal arch supporting portion and a rear portion, said pad overlying said transversely elongated forward portion and interfitting means on said pad and said forward portion of said shank to hold said pad against shifting relative to said shank, said pad having an approximately oval body portion the maximum transverse diameter of which is positioned over said transversely elongated forward portion of said shank.

7. The combination claimed in claim 6 in which said pad has a blunt forward end extending forwardly beyond said transversely elongated portion of said shank.

10. The combination claimed in claim 6 in which said body portion of said pad tapers in thickness toward the marginal edges thereof and said tapering marginal portions extend both forwardly and rearwardly beyond said forward transversely elongated shank portion.