US2065656A - Shoe last - Google Patents

Description

GQ'CLAUSING Dec. 29, 1936.

SHOE LAST Filed July 5, 1935 IN V EN TOR.

Gear 9 C/aus/h BY y Y.

A TTORNEY Patented Dec. 29, 1936 PATENT OFFICE SHOE LAST George Clausing, Portsmouth, Ohio, assignor to Vulcan Corporation, Portsmouth, Ohio Application July 5, 1935, Serial No. 29,779

2 Claims.

This invention relates to shoe lasts, and is directed particularly to the hinge means which joins the toe and heel parts of the last to permit relative movement of the last parts and a re- 5 sultant expansion and contraction of-the last as to length.

A shoe last is normally made from a solid block of wood, and this solid block of wood is later separated into two parts which are commonly known as fore and back or toe and heel parts, these parts being joined together by a suitable hinge means which permits of the necessary manipulation of the shoe last in accordance with the present well known shoe making practice. That is, collapsing and expanding of the last. Thus, the weakest point in the shoe last structure has been at the hinge area where the separate toe and heel parts are joined and where there is a V-shaped cut in the last to permit of a relative rotative movement 20 between the last parts, or collapsing and expanding of the last. When the last parts are in expanded position, there is only a small abutting area between the toe and heel parts, this abutting area being confined to a relatively small bearing surface on which one last part rotates relative to the other and a small abutting area at the bottom of the last which acts as a stop to prevent relative movement of the last parts past their normal expanded position.

It has been found that there is a tendency for shoe lasts to break at the weakest point, the hinge area, during soling or leveling of a shoe on the last. In making a shoe on the last, the last is inverted, the heel end being supported on a jack pin and the toe being supported adjacent its extreme outer end on some suitable rest. Considerable pressure is exerted on the last throughout its length during these two mentioned operations with a resultant compression force on the last at the unsupported hinge area which places a tensionstress on the hinge and a compression stress on the small abutting area between the toe and heel parts and adjacent the bottom of the last, the bottom of the last, as referred to, being uppermost during the process of making a shoe. Such compression force tends to pull the last apart at the hinge area and to crush the abutting surfaces between the toe and heel parts and adjacent the bottom of the last.

One object of this invention 'is to provide a shoe last which has substantially equal resistance to compression and tension stresses at its hinge area as it has throughout its solid remainder. In the accomplishment of this object, means are 55 provided to prevent abnormal-displacement of the toe and heel parts beyond their proper relative positions when the last is expanded, and, at the sametime, means are provided for offsetting the compression and tension forces existing at the hinge area during the leveling, soling and other 5- shoe making operations. r 1

Another object of this invention is to provide a hinge construction for connecting the toe and heel parts of a shoe last which is of a nature to I permit the axis of rotationormo'vement of the 10 one last part relative to the other to be located at a minimum distance above the bottom of the last whereby rotation or movement of one last part relative to the other in collapsing of the last will produce a maximum contraction or shortenl5 ing of the last. With this invention, the disposition of the axis of rotation between last parts at an extremely low point with relation to the bottom of the last is accomplished without lessening the strength of the hinge area.

Variousother objects and advantageous features of thisv invention may be had from the following description, and one embodiment thereof may be seen in the accompanying drawing where similar characters of reference designate corresponding parts and wherein:

1.. Fig. 1 is a side elevation of a last embodying the invention with the part adjacent to the hinge broken away to show the hinge parts in elevation, the last being shown in expanded position.

Fig. 2 is a side elevation of a last with the portion of the last adjacent to the hinge broken away to show the hinge parts in elevation, the last parts being shown in their collapsed contracted position.

' Fig. 3 is a cross sectional view of a portion of the last at the hinge thereof showing the hinge parts in plan view.

Fig. 4 is a detailed view showing a modification of the stop link. Referring to the drawing, a shoe last is shown which includes the usual toe or fore part I and heel or back part 2 connected together by a hinge means which will be presently described. It will be understood that the shoe last is ordinarily first made from a solid block of wood and the fore and back parts I and 2 are later separated by a straight and an arcuate cut to separate the fore and back parts and to provide a ball-like part 3 and a-socket 3' to form a hinge joint be- 50 tween the parts. As' shown, the back part2 is out away'at its left hand upper corner to increase the effective circumferential area of the part3 and permit the back part 2 to rotate or move about an axis at the-center of the ball-like part 55 3 relative to the fore part I. Such relative movement rotation of the parts permits the last parts to be collapsed as shown in Fig. 2 to shorten the last length for removal of the last from a shoe, or permits the last to be expanded and made longer as shown in Fig. 1, in which position the last parts are placed for the making of a shoe, the hinge joint being adjacent the last bottom, as .shown, to make this collapsing and expanding possible.

One usual connection between the fore and heel parts of the last takes the form of a spring or tension member disposed in a routed out portion in both the fore and back parts and attached at one end to the back part and at its other end to the fore part, such member ordinarily being under tension to hold the last two last parts together. The connections for the opposite ends of the spring or tension member are disposed oppositely of the hinge joint including the ball-like portion 3 in the back part and the socket portion in the fore part with the spring or tension member crossing such hinge joint. With this arrangement, considering that the back part moves or rotates relative to the fore part about the center of the hinge joint from one side to the other of the axis of rotation of the back part it tends to snap the last into its expanded or collapsed position, as the case may be, the spring or tension member being put under greatest tension just as it crosses'the axis of rotation of the back part.

In addition to the spring or tension member as a connecting means between the fore and back parts of the last, two links were ordinarily provided,'one on either side of the spring or tension member and connected at their opposite ends to the same pins to which the spring or tension member was connected, the connections between the links and the, pins being a sloppy fit so as not to interfere with movement of one last part relative to the other about the axis X. The purpose of these links was to prevent compression stress on the bottom of the last, or a lengthwise force on the last, from separating the fore and back parts which, without the links, would be connected together solely by the spring or tension member under tension. Such construction of the connecting means between the fore and back parts of the last necessitated that the hinge joint or ball and socket arrangement, or any other axis of rotation between the fore and back parts of the last, be located a considerable distance above the bottom of the last to provide abutting surfaces between the fore and back parts and at the bottom of the last, which were of sufiicient area to withstand the compression force exerted on the bottom of the last during the shoe making operation and at a time when the last was inverted and supported only at or adjacent to its opposite ends. The location of this axis of rotation a substantial distance above the bottom of the last necessarily reduced the amount of shortening of the last brought about by rotation of the back part relative to the fore part in collapsing the last. It is desirable that the axis of rotation of the back part relative to the fore part be as close to the bottom of the last as is possible.

In accordance with this invention, the fore and back parts of the last are routed out to form chambers 6 in the fore and back parts respectively, which'chambers are coincident when the last is in collapsed position as shown in Fig. 2. A spring or tension member 4 is disposed in this chamber with one of its ends connected to a transverse pin 5 in the fore part and its opposite end connected to a transverse pin 5 in the back part, the spring or tension member 4 being of a shape and the pins 5 being so located that the spring or tension member crosses the axis of r0- tation of the back part relative to the fore part during movement of the last parts into collapsed or expanded positions, and is always under tension so as to hold the last fore and back parts together. Such crossing of the spring or tension member across the axis of rotation between the fore and back parts of the last results in a snapping ,of the parts into their collapsed or expanded positions after the spring or tension member crosses the axis of rotation of the one part relative to the other, which axis is indicated at X, the spring or tension member being placed under greatest tension just as it is crossing such axis of rotation.

As shown, a link 9 is also disposed in the chamber containing the spring or tension member 4. However, in place of being disposed on the same pins 5 with the spring or tension member and across the axis X as previously practiced, the link 9 is connected at its opposite ends to transverse pins 7 and 8 by means of slots l0 and H, one in the last fore part and the other in the last back part, the pins T and 8 and the link carried thereby being disposed a substantial distance above the pins 5 of the spring or tension member 4 and the axis X. As shown in Fig. 3, two links 9 are used, these links being separated by spacers l3, although only one link may be used.

During the making of a shoe on a last'oi the type shown, the last is turned up-side down from the position shown in Fig. 1 of the drawing and is supported at one end by means of a jack pin disposed in the hole 20 provided therefor and at the other end on a suitable support on which the toe end rests adjacent its extreme end. With the last in this position, the shoe upper having been placed on the last, what is known as the soling and sole leveling operation takes place. During these two operations, considerable pressure is exerted on the bottom of the last at various points between the two supports, one at each end of the last. Such pressure tends to spread the last at the hinge connection between the fore and back parts, with the greatest compression being exerted at the abutting surfaces l6 and I1 beneath the hinge joint and at the last bottom. It also places a considerable tension stress on the spring 4 and would tend to separate the last fore and back parts were it not for the links 9 which, as hereinbefore stated, were previously disposed on the same pins 5 as the spring 4 and thus in substantially the same plane.

As will be noted in the drawing, the link or links 8, in accordance with this invention, are disposed a substantial distance above the pins 5 in the spring 4, and also above the hinge joint formed by the ball portion 3 and depression 3 with contacting surfaces I4 and I5. With the link or links 9 so located, any compression force on the last bottom and which tends to separate the last at its top and crush the last at the abutting surfaces 16 and I1 will be compensated for by the link or links 9 preventing the last from spreading at its top. At the same time, the lever arm, as represented by an imaginary line drawn from each of the pins I and 8 to the abutting surfaces 16 and I! at the bottom of the last, are so lengthened that it would take considerably more pressure than that exerted on the bottom of the last during the soling and sole leveling operations to crush the last at or near these abutting surfaces. Thus, it is possible to reduce the area of these abutting surfaces and lower the hinge joint between the last parts more closely to the last bottom.

The possibility of lowering the hinge joint between the last parts at a point closely adjacent the last bottom is highly desirable in that relative rotation of the last parts to a collapsing position as shown in Fig. 2 will result in a quicker and at the same time a greater shortening of the last length whereby the last may be collapsed and withdrawn from the shoe without danger of stretching or mutilating the shoe which has been built on the last.

In operation, the fore and back parts of the last are normally in the position shown in Fig. 1. That is, the last is expanded to the position wherein it has the greatest length and a shoe is constructed on the last while the parts are in this position. It will be noted that the pins 1 and 8 are bearing against the outer extremities of the elongated slots H] and l I. In other Words, the pins 1 and 8 are bearing against the points l2 of the slots 10 and H. Thus, it will be seen that the tendency of any pressure exerted on the bottom of the last and which tends to spread the last at its top while such last is supported adjacent its opposite ends will be resisted by the link or links 9. When the last is collapsed as shown in Fig. 2, the pins 1 and 3 move to the inner extremities of the elongated slots I0 and II. Thus, a connection is provided between the fore and back parts of the last which, while not interfering in any way with the usual collapsing and expanding movements of the last, is much stronger than any heretofore employed and which is efiective to prevent crushing of the abutting surfaces at the bottom of the last when pressure is exerted thereon. Referring to Fig. 4 of the drawing, I have shown the modified form of link 9 wherein the opening I8 is just sufficiently large to fit snugly on the pin 8 while the opening [9 which fits on the pin 1 takes the form of an elongated slot.

Having thus described the invention, I claim:

1. A shoe last comprising a fore part, a heel part, a hinge between said parts to permit expansion and contraction of the last, a spring member at said hinge tensioned to produce compression at the joint of said hinge and operable to snap said fore and heel parts into their contracted and expanded relative positions, a pair of pins rigidly secured respectively in the heel and fore parts of the last a substantial distance above the axis of said hinge, a rigid stop link having apertures in its ends within which the pins are received said apertures permitting shortening of the last and being so spaced apart with respect to the pins as to limit the rotation of the hinge beyond its normal position when the last is expanded.

2. A shoe last comprising a fore part, a heel part, a hinge between said parts to permit contraction and expansion of the last, a chamber within the body of the last, a spring member within said chamber tensioned to produce com pression at the joint of said hinge and operable to snap the said fore and heel parts relatively into their contracted and expanded positions, a pair of pins rigidly secured respectively in said fore and heel parts a substantial distance above the axis of said hinge, a pair of rigid stop links situated in said chamber having apertures in their ends within which said pins are received said apertures permitting shortening of the last and so spaced apart with respect to the pins as to limit the rotation of said hinge beyond normal position when the last is expanded.

GEORGE CLAUSING.

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