US3068524A

US3068524A - Shoe last for use in vulcanizing presses

Info

Publication number: US3068524A
Application number: US12105A
Authority: US
Inventors: Klee Werner
Original assignee: Individual
Current assignee: Individual
Priority date: 1960-03-01
Filing date: 1960-03-01
Publication date: 1962-12-18
Anticipated expiration: 1979-12-18

Description

Dec. 18, 1962 w. KLEE 3,068,524

SHOE LAST FOR USE IN VULCANIZING PRESSES Filed March 1, 1960 2 Sheets-Sheet 1 MS-WA. i r

Jn venfor:

1962 w. KLEE 3,068,524

SHOE LAST FOR USE IN VULCANIZING PRESSES Filed March 1. 1960 2 Sheets-Sheet 2 Fig; 5 12 Jnvenfor:

United States Patent f 3,068,524 SHOE LAST FDR UE IN VULCANEZHNG PRESSES Werner Klee, Uphnsen, near Achim, Germany, assignor to Herbert Ludwig, Usen, Post Achim, Germany Filed Mar. 1, 196%), Ser. No. 12,105 1 flaim. (Qt. 18-46) The present invention relates to shoe lasts in general, and more particularly to improvements in composite shoe lasts of the type utilized for holding articles of footwear in vulcanizing presses and the like.

In the vulcanizing of shoes, boots and other articles of footwear, the last is subjected to very high stresses which develop when the bottom die is moved into contact with the rubber mass that ultimately forms the sole of the article mounted on the last. Consequently, the lasts of the collapsible type are not practical for use in vulcanizing machines because the articulately joined components of such lasts cannot withstand the stresses. Particularly the hinges and the locks disposed between the individual components of collapsible shoe lasts are subjected to excessive wear and tear, and must be replaced, or the entire last discarded, after comparatively short periods of actual use.

Certain more recent constructions utilize composite lasts in which the components are movable toward and away from each other in order to alternately shorten or lengthen the shoe last. A serious drawback of such constructions is-that the material of an article of footwear is pinched between the relatively movable parts when the latter move from spaced-apart position into or toward abutment with each other. According to another prior proposal, the shoe last may be shortened by moving one or more components downwardly and beyond the general plane of the bottom face of the device. Such arrangement brings about excessive deformation of the articles mounted on the last which more than offsets the advantage that the overall length of the last is shortened for more convenient insertion into or withdrawal from a shoe or the like. Particularly the upper half of the article is subjected to very high expanding stresses which may bring about actual destruction. Moreover, the danger that the insole would knick or break is ever present.

An important object of the present invention is to provide a composite shoe last which can readily and repeatedly withstand very high stresses developing in a vulcanizing machine, whose overall length may be rapidly reduced for convenient insertion into or withdrawal from an article of footwear, and which may be safely held in operative full-lenth position in the course of a vulcanizing operation.

Another object of the invention is to provide a shoe last of the above outlined characteristics which consists of a small number of component parts, which can be manufactured at low cost, which is constructed in such a way that the article of footwear cannot be caught between its component parts, and which can be inserted or withdrawn without subjecting any part of a shoe, boot or the like to appreciable stresses.

A further object of the invention is to provide a shoe last for use in vulcanizing presses which embodies a self locking feature for holding its component parts in operative position during a vulcanizing operation, which is constructed and assembled in such a way that a comparatively short movement of one of its component parts suflices to permit convenient insertion into or withdrawal from an article of footwear, and whose relatively movable component parts are connected by rugged and longlasting joints.

With the above objects in view, the invention resides essentially in the provision of a shoe last which comprises a forward component, preferably formed at its upper and with mounting means with the help of which it may be installed in a vulcanizing machine; a heel component slidably connected to the rear end face of the forward component; and means operatively connected with both components for reciprocating the heel component between an operative position in which its bottom face is flush with the bottom face of the forward component and a second position in which the overall length of the last is reduced by moving the heel component in upward direction toward the mounting means. It is preferred to form the rear end face of the forward component in such a way that the heel component, while moving from its operative into its inoperative position, is caused to travel upwardly and at least slightly forwardly either throughout or at least in the initial stage of its movement to thereby bring about the necessary reduction in overall length of the last. In operative position, the bottom faces of both components are fully aligned with each other and the front end face of the heel component is complementary to the rear end face of the forward component so that no material can be caught therebetween.

In one of its preferred forms, the rear end face of the forward component is formed as a concave surface whose center of curvature is lacated at a point rearwardly and externally of the shoe last, or said rear end face may assume the form of a straight upwardly and forwardly inclined surface. The means for reciprocating the heel component with respect to the forward component may comprise a lever-actuated eccentric system, a toggle mechanism, a system of meshing gears and toothed members in the form of gear segments, or a similar structure. It is preferred to provide stop or abutment means adjacent to the bottom face of the forward component which arrests the heel component in its operative position, and to further provide means for locking the heel component in such position. Alternately, the eccentric or toggle mechanism which recipro-cates the heel component may be provided with a self-locking feature to positively hold the heel component in operative position, i.e. in a position in which the bottom faces of both components are properly aligned with each other.

Otherfeatures of the invention reside in the provision of very rugged and wearresistant guide means, preferably dovetailed joints defined by the end faces of both components, for controlling the movements of the heel component with respect to the forward component; in the selection of especially suitable heat conducting substances as a material of both components; and in such mounting of the heel component that an article of footwear mounted on the improved shoe last has a natural tendency to slip off the latter when the heel component is moved in a direction away from the bottom face of the forward component.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claim. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following detailed description of three specific embodiments when read in connection with the accompanying drawings, in which:

FIG. 1 is a side elevational view of a shoe last for use in a sole vulcanizing machine which embodies one preferred form of the invention, the last being shown in operative position;

FIG. 2 is an end elevational view of the last as seen from the right-hand side of FIG. 1;

PEG. 3 is a greatly enlarged fragmentary sectional view showing the connection between the upwardly reciprocabie heel component and the reciprocating means there- Patented Dec. 18, 19132 for, the section being taken along the line IIIIII of FIG. 1, as seen in the direction of arrows;

FIG. 4 illustrates the last in inoperative position during insertion into or withdrawal from an article of footwear;

FIG. 5 is a side elevational view of a modified shoe last in operative position which it assumes in an article of footwear during the vulcanizing operation;

FIG. 6 is a side elevational view of a shoe last constructed in accordance with a third embodiment of the invention, the last being shown in operative position; and

FIG. 7 is a side elevational view of the shoe last of FIG. 6 in inoperative position.

Referring now in greater detail to the illustrated embodiments, and first to the embodiment of FIGS. 1 to 4, there is shown a last 3 of the type utilized for mounting an article of footwear in a sole vulcanizing machine, better known as a vulcanizing press. The last preferably consists of aluminum which is a very good heat conductor, but it may be made of steel or another suitable metallic substance. The upper end of the shoe last proper, i.e. of that part which is actually receivable in an article of footwear, is integrally connected with mounting means 1 in the form of a substantially rectangular block by means of which the last is rigidly held in the press during a vulcanizing operation. In addition, the mounting means 1 carries the arrangement which reciprocates the heel portion 5 of the last in a manner to be described in full detail hereinafter.

The last 3- comprises a forward portion or component 4 and a rear or heel component 5. The rear end face 2 of the forward or main body portion 4 is of concave shape, and the heel component 5 is formed with a complementary convex front end face 5a which slides along the concave end face 2 when the heel component is moved into and between the positions of FIGS. 1 and 4. The end face 2 is formed with arcuate guideways 18 and the front end face 511 comprises suitable tenons 18a constituting with guideways 18 a dovetail joint which slidably guides the heel component 5 along the concave rear end face 2. It will be readily understood that the

assembly

18, 18a may be replaced by a different joint as long as the joint is capable of satisfactorily guiding the heel component 5 with respect to the forward component 4.

The upper end face of the heel component 5 carries a reinforcing plate 6 which is rigidly secured thereto by one or more screws or other fastening means. This plate carries a pair of symmetrically arranged angular sliders 11 whose inwardly projecting flanges extend into substantially elliptic recesses or channels 16 formed in the opposing sides of an eccentric reciprocating element 9. The latter is received in a cutout 1a provided in and extending forwardly from the rear end face of the mounting means 1 and is mounted olf center on a transverse shaft or pivot axle 8. The shaft 8 is formed with a key 3a which extends into a complementary groove of the nearly elliptical eccentric element 9 so that the

parts

8, 9 always move in unison. The shaft is rotatable by a handle or lever 7 which is non-rotatably secured thereto by one or more screws 19, by a key, or in any other suitable manner.

When an operator desires to shorten the last 3, i.e. either prior to the introduction into an article of footwear or for withdrawal from the latter, the actuating lever 7 is preferably pivoted in forward direction, i.e. toward the toe portion of .the forward component 4, whereby the eccentric reciprocating element 9 moves into the position of FIG. 4 causing the sliders 11 to travel in their respective recesses 19 and to move the heel component 5 upwardly and along the arcuate rear end face 2, the component 5 being guided in such movement by the dovetail joint 18, 181:. T he connection between

parts

6, 11 on the one hand and the heel component 5 on the other hand may comprise one or more bolts 6a indicated in MG. 3 by two vertical dot-dash lines.

When the heel component 5 assumes its extreme uppermost or releasing position which is shown in FIG. 4, the sole or bottom face of the composite last 0 is shortened by a distance a which equals the length of the bottom face of the component 5. Such shortening of the last is always sufficient for convenient insertion or withdrawal of the last from anarticle of footwear particularly since, and as may be readily observed in FIG. 4, the lower half of the heel component 5 in the latters uppermost position actually moves forwardly and into the cavity bounded by the arcuate end face 2. The phantom line 5p indicates the outline of component 5 in its extreme lowermost or operative position.

An important advantage of the construction shown in FIGS. 1 to 4 is that no slot is formed between the

adjacent end faces

2, 5a of the components 4, 5, respectively, such as could bring about a pinching or jamming of the shoe upper or of the inner lining between the two components. The height of the heel component 5 is such that it preferably always extends beyond the upper edge of the shoe upper so that the latter cannot be wedged be-- tween the reinforcing plate 6 and the end face 2 when the heel component is caused to move in upward direction.

When the last 3, assumed to be in the position of FIG. 4, is properly inserted into an article of footwear or into a shoe upper prior to the application of a sole thereto,- the lever 7 is pivoted back into the position of FIG 1 whereby the shaft 8, the eccentric 9, the sliders 11 and the plate 6 return the heel component 5 into the latters extreme lowermost position in which its bottom face is again flush with the bottom face of the forward component 4. The shoe upper is thereby stretched and maintained in proper position so that the rubber outsole may be vulcanized thereon.

The reference numeral b indicates in FIG. 4 the vertical distance between the bottom face of the heel com ponent 5 in operative lowermost position and the center of curvature of the rear end face 2. This distance b preferably equals or approximates the height of the vamp or of the counter of the article of footwear which is proc-* essed on the improved last, i.e. the radius of curvature of the end face 2 is at the level of the upper edge of a shoe on the last 3. When the distance b is selected in the just described manner, the upper half of the heel com= ponent 5 will begin to advance rearwardly and beyond the outline 5p only when it moves to a level above the upper edge of the shoe upper, i.e. when it is already with drawn from the latter. The outline 5p actually repre sents the outline of a human heel, the so-called heel arch which, as i well known, begins to curve inwardly and forwardly at the lower end of the Achilles tendon, i.e. above the heel bone. By moving along such an arc, .the heel component 5 is readily insertable into or removable from a shoe upper without subjecting the latters upper edge portion to excessive expanding stresses. In other words, the upper half of the heel component 5 moves rearwardly of the actual outline of a shoe upper only when the last 3 is already in the inoperative position of FIG. 4-. Of course, when the article of footwear deviates from its customary shape in that its upper comprises a high top, the upper half of the heel component 5 will bear against the backstay. However, this presents little or no problem because the top and the backstay are not reinforced and, therefore, can yield to an extent much greater than the stiff counters of a shoe. In addition, and as is also observable in PEG. 4, the rear edge of the heel component 5 slopes downwardly and forwardly whereby a shoe mounted on the last 3 has a natural tendency to slip off the forward component 4. Consequently, the improved last is equally useful as a holder for low or very high articles of footwear during a vulcanizing operation.

When the lever 7 is actuated to turn the eccentric reciprocating element 9 and to move the heel component 5 into the extreme lowermost position, the latter is arrested by a suitable abutment or stop 20 which is provided at the lower end of the rear end face 2, i.e. close to the bottom face of the forward component 4. The stop 20 prevents the movement of component 5 into a position in which the latters bottom face would project beyond the bottom face of the forward component 4, i.e. the underside of the composite last 3 then presents a smooth, continuous surface. The stop 20 is preferably provided at the lower end of the dovetail joint 18, 18a.

A very important advantage of the comparatively solid and hence strong eccentric reciprocating element 9 is that it provides a very stable connection between the parts 1, 4 on the one hand, and the heel component 5 on the other hand. In addition, and as may be observed in FIG. 1, when the heel component 5 abuts against the stop 24), the eccentric element 9 is moved at least slightly beyond its dead center position whereby it locks the heel component in the extreme lowermost position unless the lever 7 is actuated by hand to move the eccentric element to the other side of the dead center position.

FIGS. 1 and 4 illustrate that a space receiving the plate 6, the sliders 11 and the lower portion of eccentric element 9 is formed between the upper end face of the heel component 5 and the cutout 1a in the rear portion of the mounting means 1. This space is especially large when the component 5 is in the position of FIG. 1 and provides room for movements of said component into the position of FIG. 4. Though it does not in any way affect the operation or usefulness of the last 3, such space nevertheless is undesirable insofar as it exposes certain moving parts and may permit accumulation of foreign matter such as could, in the long run, affect the movements of the heel component, for example, by permitting entry of dust into the grooves 18 (see FIG. 2). The shoe last 3 of FIG. 5, though very simillar to the device of FIGS. 1 to 4, comprises a modified heel component 5 which is shaped in such a way that no space is formed along the rear end face 2' of the forward component 4. When in operative position of FIG. 5, the component 5 completely fills the cavity bounded by the rear end face 2. The means for reciprocating the component 5 with respect to the forward portion or component 4' comprises a spur gear 12 which is received in a cutout 1a formed in the rear portion of mounting means 1 and which is non-rotatably mounted on a transverse shaft 8', the latter being rotatable in the mounting means 1' and traversing the cutout 1a. The connection between the handle 7 and the shaft 8' is such that these parts always move in unison. The teeth of gear 12 mesh with the teeth of a segment 13 which is rigidly secured to the upper face of the heel component 5' and forms an extension of the arcuate front end face 5a. The latter also carries one member of the sliding dovetail joint 18', 18a which is adapted to guide the heel component in movements between the two extrerne positions. The abutment means 20' prevents downward movements of the component 5 beyond the position of FIG. 5. The length of front end face 50 equals the length of the rear end face '2'.

When the lever 7 is pivoted in forward direction, the toothed means 12, 13 bring about an upward movement of the heel component 5' whereby the latters pointed upper end portion travels upwardly and rearwardly beyond the mounting means 1' to shorten the combined bottom face of last 3 in the same manner as described in connection with 'FIGS. 1 to 4. In such position, the last 3' may be readily inserted into or withdrawn from an article of fotwear. When the last is properly received in the shoe, the lever 7' is pivoted back into the position of FIG. 5 to thereby move the heel component 5 along the rear end face 2. and into abutment with the stop means 20'. A schematically represented locking pin 21 or the like is then inserted through a pair of aligned bores in the heel component 5 and mounting means 1 to prevent undesired rotation of the gear 12 into heel-lifting position. Such locking means should preferably be provided because the heel reciprocating gear 12 is coaxially mounted on its shaft 8' and, therefore, has no dead center position in which it could automatically lock the heel component in place as the eccentric element 9 of FIGSQ. 1 to 4. The locking means 21 resists the pressure which is exerted against the bottom face of the composite shoe last 3 during a sole vulcanizing operation.

Accurate formation and finishing of arcuate end faces 2, 5a and 2, 5a on the components of shoe lasts 3, 3' respectively, adds somewhat to the manufacturing cost of these devices. Such cost may be reduced by constructing the shoe last in the manner shown in FIGS. 6 and 7. The forward component 4 of the last 3" is formed with a straight, forwardly and upwardly inclined rear end face 2" which cooperates with the straight front end face 5a" of the heel component 5". The inclination of the end face 2 with respect to the general plane of the bottom face of the forward component 4" is between 45 and degrees and, as shown in FIGS. 6 and 7, preferably closer to 90 degrees than to 45 degrees. In fact, the inclination of the lower halves of arcuate end faces 2 and 2, too, is within this general range. The provision of straight end faces 2", 5a" greatly simplifies the formation of the dovetail joint 18", 18a" since the latters components, too, extend along straight lines.

The heel component 5" is reciprocated by a toggle mechanism comprising an actuating lever 7" which is keyed on a transverse shaft 8" rotatably carried by the mounting means 1" of the forward component 4"; a first reciprocating link 14 which is non-rotatably fixed to the shaft 8"; and a second reciprocating link 16 which is articulately connected with the link 14 and with the heel component 5" by means of pivot pins 15, 17, respectively. The pins 15, 17 are parallel with the shaft 8". The downward movement of the heel component 5" is limited by a stop or abutment means 2h" located close to the bottom face of the forward component 4".

The toggle mechanism operates as follows: When the operator desires to withdraw the heel component 5 in upward direction, he pivots the lever 7 in rearward direction whereby the

links

14, 16 cause the heel component to travel along the forwardly inclined rear end face 2.", the heel component being guided in such movement by the sliding dovetail joint 18", 18a". It will be readily understood that the toggle mechanism must be of rugged construction in order to withstand stresses exerted against the underside of the heel component during a vulcanizing operation. This also applies to the guide means 18", 18a. In the construction of FIGS. 6 and 7, the actuating lever '7" preferably extends into the cutout 1a" of the mounting means 1"; however, such construction is equally possible in the shoe lasts 3 and 3.

As is shown in FIG. 6, the heel component 5" comes into abutment with the stop 20" when the toggle mechanism including the parts 7", 8", and 1447 moves at least slightly beyond its dead center position, i.e. the tobble mechanism embodies a self-locking feature which prevents upward movement of the heel component when the last 3" is in actual use.

It will be understood that the reciprocating means of the embodiments shown in FIGS. l4, 5 and 6-7 may be interchanged, if desired. For example, an eccentric reciprocating system may be utilized in the last 3", or the last 3 may comprise a system similar to the one shown in FIG. 5 merely by adding one or more intermediate gears between the gear which is operated by the actuating lever and the toothed means on the heel component. Moreover, the configuration of the mounting means which forms part of the forward component may be changed, if desired, to fit into different types of vulcanizing presses.

Regardless of whether the forward component is formed with a concave or with a forwardly and upwardly inclined rear end face, upward movement of the heel component along such end face invariably results in sufficient reduction in the overall length of the shoe last so that the latter is readily insertable into and removable from an article of footwear without damaging the upper part thereof.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic and specific aspects of this invention, and therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claim.

What is claimed as new and desired to be secured by Letters Patent is:

A variable-length shoe last for use in vulcanizing presses and the like, said last comprising, in combination, a forward component having a bottom face and a concave rear end face extending upwardly from said bottom face, said rear end face having a center of curvature located rearwardly and externally of said last and that portion of said rear end face which is adjacent to said bottom face being inclined in forward direction; mounting means for said last located above and rigid with said forward component and having a top face; a heel component having a top and a bottom face and a convex front end face complementary to and connected with the rear end face of said forward component slidably along the same, the height of said heel component being smaller than the combined heights of said forward component and said mounting means; and reciprocating means operatively connected with said components for sliding said heel component along said rear end face of said forward component from an operative position in which the bottom faces of both components are aligned with each other in direction toward said top face of said mounting means into a releasing position a distance not exceeding the cliiference between said combined heights of said forward component and said mounting means and the height of said heel component so that also in said releasing position the top face of said heel component is not located above said top face of said mounting means, the length of that portion of the shoe last which includes the portions of said components adjacent to the respective bottom faces being reduced when the heel component is moved from said operative toward and into said releasing position whereby the shoe last may be conveniently inserted into and Withdrawn from an article of footwear.

References (liter! in the file of this patent UNITED STATES PATENTS 1,424,343 Crawford Aug. 1, 1922 1,432,217 Stewart Oct. 17, 1922 2,566,686 Ulcek Sept. 4, 1951 2,932,064 Farmer Apr. 12, 1960 FOREIGN PATENTS 1,102,280 Franc Oct. 18, 1955 302,134 Switzerland Oct. 15, 1954