US1833116A - Last - Google Patents

Description

Nm r.i24, 1931, P. F. w. c. KRIPPENDORF 1,333,116

. LAST Original Filed Jan. 23, 1926 f /NVENTUR ww/CFMQ/ A I 5 Letters Patent Patented Nov. 24, 1931 UNITED STATES PA-TENT}. OFFICE PAUL I. W. (.1.v xnnrmvnonr, OI LYNN, IASSLCHUSETTS, ASSIGNOB, BY MESH] Al- SIGNHENTS, TO UNITED SHOE MACHINERY IEBSEYQ A 60320342101 OF NEW JERSEY CORPORATION, 01' PATERBON, m

Original inflation filed January 28, 1926, Serial No. 83,878, new Patent No. 1,751,742, dated larch N,

1am. Divided gnd this application filed Anrult 8, 1929. Serial No.

which is substantially at the ball line of the This invention relates to improvements in lasts and is illustrated as embodied in a last adapted for use in the manufacture of shoes'of the-ty disclosed in United States $0. 1,7 51 742, granted March 25, 1930 on my copending application of which this ap llcation is a divlslon. v

Objects of t is invention are to produce a last tolbe' used in the manufacture of shoes which .while retaining all the style and shapeextremely comfortable to wear but will also liness characteristic of good shoe-making will at the same time so meet the natural reuirements of a normal human foot that 8. Shoe constructed thereon will not only be tend to prevent development of any abnormalities, such for example, as falling'arches, and when such deformities have occurred, will tend to correct the same.

59 From a study of impressions of the normal human foot in lastic material and from considerations of t e anatomy of the foot I have discovered that a support for the forepart of the foot, such as the inside of a shoe, should :5 be flat for a considerable area, this area being roughly triangular, the base of the trian le corresponding substantiall to the ball line of a last which may be de ned as a line extendin transversel of the last a short disgsay one-hal inch) at the rear of the line joining the anterior ends of the first and fifth metatarsal bones. The apex of the triangle lies bet-ween thephalanges of the great toe and the second toe. This flat trian ular area should lie in a plane substanially parallel to the tread that is for example, the; one ofthe tread face 0 the heel extende forwardly. The forepart area outside of this approximately plane of the shoe vtriangular areashould extend upwardly and outwardly to a degree approximating the usual spring of a last.

Accordingly, in an important aspect, the

45 present invention consists in a last having the tread surface of the forepart flat over a substantially triangular area. To this end, the bottom of the forepart of the illustrated last is formed with a substantially flat por- 50 tion in the form of a triangle the base of last and the apex of which lies between the great and second toes, the forepart area outside of the triangular area from the ball line forward" being directed upwardly and outwardly to an extent substantially approximating the usual spring of a last. In a made on a last of this construction the surface below the anterior metatarsal arch is fiat and hence offers no resistance to the natural flattenin of the arch as the foot is bent in walking and at the same time prevents the flattening movement from going too far as would be the case if this surface were transversely concave. Moreover, since the ball line of the shoe at which the bend of the toes should occur in walkin is perfectly straight, the maximum flexibility of the sole at this line is afforded, for obviously an transverse curvature of the sole along this line would tend 'to stiffen the sole.

It is observable that when the foot is pressed lightly on a flat surface'the ends of the toes are slightly raised from that surface hence, by the structure described com r' a fiat, triangular area with an upwardly and outwardly extendingmargin, a support for the toes in their natural position is afforded.

principal nerves and blood vessels of the foot run along near the outer side of the foot just inside of the bearing point referred to. In fact, most of these nerves and blood vessels will be found to lie approximately above a line drawn from about the center of the breast matatarsal bone where it joins the cuboid bone. The

line to the outer end of the ball line of the shoe. Hence, it is desirable to avoid any pressure upon the-bottom of the foot in the region of this line which would tend to interfere with the nerve control, blood circulation or muscular action.

Accordingly, in accordance with another feature of the present invention, the illustrated last is provided with a shank portion which extends in a straight line from about the center of the breast line of a shoe constructed thereon to a oint adjacent the outer end of the ball line. y thus dispensing with any lon 'tudinal arch along this line, pressure suc as would interfere, in a shoe constructed u on the usual last, with the free action of t e tendons, impede circulation in the blood vessels or impair the function of the nerves is avoided.

At each side of the above-mentioned straight line the shank of the illustrated last has a pronounced transverse curvature especially at the inner side of the shank in or er that a shoe constructed on the last will fit well into the hollow or longitudinal arch of the inner side of the foot so as to conform to the anatomical structure of the foot.

In the drawin s,

Fig. 1 is a si e elevation of a last used in making the shoe;

Fig. 2 is a pore ective view showing the llu ottom surface 0 the last illustrated in ig. 3 is a view of the plantar surface of the bones of a normal human foot.

Referring to Figs. 1 and 2, which represent a last 10, it will be seen that there is upon the forepart of the last bottom a flat area bounded by a line having a curved part 12 and a straight part 14. In Fig. 2 a heavy broken line A, B, C, D has been drawn upon the last bottom to assist in describing various characteristics of the last. The line B-C represents substantially the ball line or, as shown in Fig. 3, the line joining the centers of the anterior ends of the first and fifth metatarsal bones. The line C-D is e ual in length to B-C, and the angle BC is a right angle. It is found that the line C-D re resents very approximately the direction 0 the first phalanges, that is, the direction of the great toe. It will be noted that the area enclosed by the triangle BOD approximates the area enclosed by the line 12, 1a, the shape of the trian le having been rounded and softenedby t e curved line 12 and the straight portion 14: corresponding substantially to the ball line of the last. The

line 12 defines a shape forward of the ball line approximating the shape of the forepart of the last, and between the line 12 and the periphery 16 of the forepart of the last is a crescent-shaped area 18 which slopes outwardly and upwardly or toward the body of the last from the line 12. This is best seen from Fig. 1 where the last is represented as having the flat surface of its forepart pressed upon a fiat tread surface F-G. It will be seen that the peripheral line 16 extends from the ballline forwardly and upwardly in a gentle curve representing approximately the.

spring of a usual last. This figure also indicates the vertical curvature of the crescentshaped surface 18. It will be noted also that the rear ortion of the last is raised from the surface %-G a distance representing the height of the heel required for the last. The flat area of the forepart bounded by the line 12, 14 represents the area of the forepart of the foot which presses u on a flat surface in the act of standing. he crescent-shaped marginal area has the described outward and upward inclination for the purpose of supportin the toes in what is their natural position, t at is, slightly elevated from the fiat tread surface, and the projection of the widthwise extent of the marginal area upon the plane of the last bottom is, as illustrated, substantially greater than the heightwise di placement of the edge of the margin toward the body of the last above the plane of the last bottom.

The line B-O represents approximately the line on which the forepart of the foot bends and the line 1% parallel to it represents the ball line of the last and approximately the line along which the insole of a shoe constructed on applicants last has to bend in the act of walking. The line along which the insole has to bend is therefore straight and maximum flexibility of the insole is assured since there is no transverse curvature of the sole at the ball line to interfere with its bending. This fiat surface along the ball line BC permits the anterior transverse arch of the foot to flatten out as 'it naturally does when the toes are bent and pressure is applied to the ground in walking and it revents this arch from bending too far as is t e case when the surface pressed on is concave as it frequently is instead of flat.

The line A-B extends from about the center of the breast line represented by the forward edge of a heel plate 20, secured to the heel-seat of the last, to the outer end B of the ball line and is a strai ht line, the surface of the shank portion 0% the last having no vertical curvature along this line.

It has been found that many of the important blood vessels, nerves and tendons of the foot lie adjacent to the vertical plane of the line A-B, and that any upward arch of the shank portion of the shoe along this line tends to produce pressure upon these blood vessels, nerves and tendons and to interfere with circulation, sensation and normal action of the foot muscles. For example, the tendon is: through the and the portion of the tendon straight line zismoespecia yl benotedthatthe ve through which the tendon of the le peroneus longus passes to its point 0 attach- I muscle peroneus longus hel groove 22in the plantar surface of the cuboi bone,

muscle ment at 24 to the posterior portion of the vfirst metatarsal bone, lies over this line. Since the line A-B is a straight line while the foot has a slight natural longitudinal arch above this line, objectionable pressure upon these tendons is avoided. The normal action of the in maintainin the posterior transverse arc of the foot an hence my construction, which prevents pressure upon and interference with this tendon and hence with its muscle, avoids a frequent cause of foot trouble.

At each side of the straight line A- -B the shank portion of the last is transversely curved as indicated at 6 and 8 in Fig. 2. The rtion 8 is curved to conform closely to the ongitudinal arch of the foot. The shoe constructed on this last will, therefore fit closely to the arch of the wearers foot and will tend to preserve the natural arch of the foot. The

transverse curvature of the shank. portion either direction so that the tendency of the wearer to run the shoe over on either side is obviated.

The heel-seat surface of a last represented by the plate is made very convex so that a to receive the heel portion of the foot and prevent lateral movement of the foot with respect to the heel, thus avoiding running over of the heel.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent of the United States is:

1. A last having the tread surface of its forepart flat over a substantially triangular area, the base of the-triangle being the ball line of the last, and the apex of the triangle lying substantially between the points corresponding to the ends of the first phalanges of the great and second toes.

area, the base of the triangle being the ball line of the last and the apex of the triangle lying substantially between the points corresponding to the ends of the first phalanges of the great and second toes, the forepart tread surface area outside the said triangular area being directed upwardly and outward- 3. A. last having a tread surface in which L the outer side of the shank portion is substanaffords a support for the shank of the foot inpronounced cup will be formed in the insole 2. A last having the tread surface of its forepart flat over a substantially triangular ti straigh' talong' alineexten' from th e zenteroftheheelbreast a biter Egint adjacent to the outer so of the ball 5. A last for welt shoes having the margin of its forepart only inclined outwardly and toward the body of the last, the rejection of the widthwise extent of said inc ed margin upon the plane of the last bottom being substantially greater than the heightwise displacement of its outer edge above the plane of the last bottom, and the widthwise extent and the heightwise di lacement of the margin increasin tower the toe end of the set whereby e heightwise displacement of the outer edge of the inclined mar approximates the spring of an ordinary iii In testimony whereof I have signed my name to this sgccification.

PAUL W. C. KRIPPENDORF.

extending

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