US3276054A

US3276054A - Two-part last

Info

Publication number: US3276054A
Application number: US484869A
Authority: US
Inventors: Julius G Winkler
Original assignee: International Vulcanizing Corp
Current assignee: International Vulcanizing Corp
Priority date: 1965-09-03
Filing date: 1965-09-03
Publication date: 1966-10-04
Anticipated expiration: 1983-10-04

Description

J. G. WINKLER 3,276,054

TWO-PART LAST Oct. 4, 1966 2 Sheets-Sheet 1 Filed Sept. 5, 1965 HTT'K? Z & pm 1 g l gwwaw Oct. 4, 1966 J. G. WINKLER 3,275,054

TWO-PART LAST Filed Sept. 5, 1965 V 2 Sheets-Sheet 2 United States Patent M 3,276,054 TWO-PART LAST Julius G. Winkler, Lexington, Mass., assignor to International Vulcanizing Corporation, Waltham, Mass., a corporation of Massachusetts Filed Sept. 3, 1965, Ser. No. 484,869 Claims. (Cl. 12135) This invention relates to the manufacture of shoes wherein an upper assembly of suitable kind mounted on a metal last is held against the open top of a mold for attachment of a bottom of moldable elastomer, either disposed in the mold in the form of a blank or injected thereinto, and more especially to a last constructed and arranged to facilitate removal of the finished shoe therefrom.

Lasts embodying relatively movable parts have long been used in shoe manufacture to enable foreshortening the last after the shoe has been completed thus making it easy to remove the finished shoe. Conventionally the parts, whether articulated or slidable, have required considerable manual distortion of the shoe even to effect such foreshortening and this is especially undesirable in molding operations because the finished shoe is still uncomfortably hot and distortion, while in this state, tends to remove some of the shape imparted thereto and to stress portions which have not entirely set.

The principal objects of this invention are to provide a last constructed and arranged to facilitate freeing the finished shoe without manipulation, that is, handling of the shoe and without distortion of the shoe; to provide a two-part last of relatively simple construction which enables preserving the bottom line of the shoe during freeing and disengagement 0f the shoe from the last; to provide a two-part last constructed and arranged to minimize flow of the bottom-forming composition into the interfacial spaces between the relatively movable parts; and to provide a two-part last with means for efiecting relative movement of the parts which is of simple construction, easy to operate and is operable to hold the parts displaced until it is desirable to remove the shoe.

The invention will now be described in greater detail with reference to the accompanying drawings wherein:

FIG. 1 is an elevation of a two-part last according to this invention, showing the parts in their normal operative position;

FIG. 2 is a corresponding elevation of the two-part last, omitting the support and part of the operating mechanism, with the parts displaced relative to each other in a direction to foreshorten the last;

FIG. 3 is an elevation similar to FIG. 2, showing the last with the parts in operative position and with a finished shoe supported thereon;

FIG. 4 is a view similar to FIG. 2, showing the parts displaced and with the finished shoe disengaged by such displacement;

FIG. 5 is a section taken on the line 55 of FIG. 2;

FIG. 6 is a section taken on the line 6-6 of FIG. 4;

FIG. 7 diagrammatically shows the displacement of the movable part of the last relative to the fixed part of the last with respect to the back line of a shoe;

FIG. 8 is a bottom view of an alternative construction embodying a part at the rear end of the forepart of the two-part last operable to assist in preserving the line of the bottom upon disengagement; and

FIG. 9 is an elevation of the modified last illustrated in FIG. 8.

The invention is illustrated herein for use with a machine of the kind disclosed in Patent No. 2,878,523, dated March 24, 1959, wherein two lasts L are supported diametrically opposite each other on a rotatable shaft 10 for movement alternately from a loading position above 3,276,854 Patented Oct. 4, 1966 the axis of the shaft to a position below the axis of the shaft for engagement with the top of an open top mold (not shown) into which a bottom blank may be placed or into which bottom-forming composition may be injected for forming to the bottom of an upper mounted on the last.

The last L which forms the subject matter of this invention is rigidly secured to a block 12 which, in turn, is mounted on the shaft 10 and comprises a part 14 and a part 16 which collectively embody a forepart 18, a heel end 243 and a neck 22. The last is divided to provide the

parts

14, 16 in a plane which is transverse to the bottom and which inclines rearwardly, so that movement of the parts relative to each other in the inclined plane, as indicated in FIGS. 2 and 7, will foreshorten the last, that is, decrease the length of the last by an amount Y. The angle of the plane of division on which the parts have relative movement is chosen so that the rear surface of the part 16 clears the inside of the shoe at the heel end without rubbing or binding and so that a sufiicient portion of the bottom of the last is embodied in the forepart to support the finished shoe and to preserve the bottom line during such disengagement. As herein illustrated, the

angle is 70 and at this angle the locus of movement of the top line of the shoe S at the back line is substantially parallel to a tangent to the back line of the last which passes through the top line of the shoe as shown in FIG. 7. This angle will of course vary somewhat with the style of the shoe.

As illustrated, the

parts

14 and 16 are divided from each other in the aforesaid inclined plane to form the

bearing surfaces

24 and 26 on the forepart and rear part respectively, and also in a plane perpendicular to the

surfaces

24 and 26 to provide mutual-1y

engageable shoulders

28 and 30 on the respective parts located forwardly of the plane of the bearings for supporting the parts in their normal operative position.

The parts 14 and 16- are guided during their relative movement from their operative position, such as illustrated in FIGS. 1 and 3, to the foreshortened position of the parts by means of interengaged portions at the interfaces of the

bearings

24 and 26 in the form of a dovetail r-ib 32 and an undercut recess 34 within which the dovetail is slidable. For convenience in manufacture, the rib 32 (FIG. 6) is formed on a thin face plate 36 fastened to the part 16 by means of screws 38.

The part 16 contains, as shown in FIG. 1, a recess 40 within which there is mounted a spring-pressed ball 42 (FIG. 5) which normally releasably holds the

parts

14 and 16 in their operative positions by engagement with a recess 44 (FIG. 1) in the part 14.

Displacement of the

parts

14 and 16 relative to each other is provided for by linkage 46 comprising a lever 48 pivotally mounted on the block 12 on a pivot 50 located rearwardly of the plane of the bearings with a part 52 forwardly of the pivot and a part 54 rearwardly of the pivot. A link 56 is pivotally connected at one end to the forward part 52 of the lever and at its other end to the part 14. A handle 58 is connected to the part 54 rearwardly of the pivot. Clockwise movement of the lever 48 about the pivot 50 will raise or elevate the part 14 relative to the part 16 to the position shown in FIGS. 2 and 4. The lever and link are so proportioned that when the two are aligned as shown in FIGS. 2 and 4, they will support the part 14 in its elevated position without holding onto the lever. This enables the operator to disengage the shoe from the last and, if desired, leave it in the disengaged position until it is completely cool. To restore the parts to their operative position the lever must be rotated in a counterclockwise direction to break the knee at the forward end where it is pivoted to the link. Power-operable a means may be substituted for the manually-operable linkage, for example a piston and cylinder assembly.

As thus constructed, the parts may be conveniently heated by means of heating cartridges Cx and Cy inserted in

holes

60 and 62 drilled respectively in the

parts

14 and 16. The heating cartridges are connected by flexible wiring 64 to a suitable source of electrical power.

In an alternative form of the last illustrated in FIGS. 8 and 9, the part 1411 has a flange-like extension 66 at the bottom which extends rearwardly therefrom across the upper extremities of the bearing surfaces 24a and 26a and is nested, when the parts are in their operative position, in a shallow, correspondingly-shaped recess 68 in the part 16a. The overlap of the extension 66 helps to prevent the bottom-forming composition from being forced into the clearance space between the bearing surfaces 24a and 26a.

The extension 66 also embodies a rearwardly extending tongue 70 which is recessed into the bottom of the part 16a and provides, in conjunction with the extension 66, means for supporting the inside of the shoe during relative movement of the parts 14:: and 16a to further assist in preserving a straight line, that is, undistorted disengagement of the shoe from the last.

Although the twopart last illustrated herein is described with specific reference to apparatus shown in the patent referred to above, it is within the scope of the invention to use a last of this kind with any conventional molding equipment embodying a single last or a plurality of lasts and not only to use such a last for the making of shoes by injection molding, but also shoes manufactured in conventional fashion to enable easily removing the finished shoe from the last upon completion and that such lasts may be made of wood and/or plastic instead of metal.

The utility of the last has been described with special reference to removing a finished shoe from the last following, for example, a bottom molding or attaching operation to enable removal without distortion of the finished shoe. It is to be understood however that it is equally useful in mounting shoe upper assemblies on the last preparatory to forming or attaching a bottom thereto and, in particular, to lasted upper assemblies wherein the upper has been flat lasted to an insole or stitch-lasted to an insole so that it would be difficult to mount the upper on the last without bending and/ or stretching it which naturally would remove some of the fit achieved by the lasting operation. Hence it is within the scope of the invention to use the two-part last herein described to facilitate mounting a shoe assembly thereon and this is carried out by displacing the forepart upwardly relative to the back part, slipping the shoe assembly onto the forepart and then lowering the forepart so as to bring the heel end of the shoe assembly into engagement with the back part without having to distort the shoe assembly.

It should be understood that the present disclosure is for the purpose of illustration only and that this invention includes all modifications and equivalents which fall within the scope of the appended claims.

I claim:

1. A last comprising a fixed back part and a movable forepa-rt, said parts having confronting bearing surfaces dividing the last in a plane which commences in the bottom adjacent the heel end and which extends forwardly substantially parallel to a plane tangent to the most rearwardly convex part of the back line of the back part, said forepart being movable rearwardly relative to the back part, means pivotally connecting the parts, said means being operable to effect movement of the forepart from a position in which the bottom portion of the forepartis in alignment with the bottom portion of the back part to a position in which it is displaced upwardly therefrom,.a part extending rearwardly from the forepart, said part having a surface in the plane of the bottom, said back part containing a recess within which said part is adapted to nest with its surface in the plane of the bottom of the back part when the forepart and back part are in alignment and from which it is elevated when the forepart is elevated to shorten the last, said part overlying the upper extremities of the confronting faces of the bearing surfaces.

2. A last according to claim 1, wherein the part overlying the upper extremities of the confronting faces of the bearing surfaces has a rearwardly projecting tongue transversely narrower than said part which extends rearwardly therefrom substantially to the center of the heel seat area at the bottom of the back part.

3. A last according to claim 1, wherein the part overlying the upper extremities of the confronting faces of the bearing surfaces is a plate recessed into the bottom of the forepart adjacent the interfaces of the forepart and back part.

4. A last according to claim 1, wherein there is a recess and spring-pressed detent, respectively, in the confronting faces of the bearing surfaces interengageable to hold the parts in alignment.

5. A last according to claim 1, wherein one of the parts is provided on its confronting surface with a wear plate secured thereto, said wear plate embodying a dove tail rib and said other part contains in its confronting face a dove tail groove slidably engaged with said dove tail rib and cooperable therewith to hold the parts slidably engaged.

References Cited by the Examiner UNITED STATES PATENTS PATRICK D. LAWSON, Primary Examiner.

Claims

1. A LAST COMPRISING A FIXED BACK PART AND A MOVABLE FOREPART, SAID PARTS HAVING CONFRONTING BEARING SURFACES DIVIDING THE LAST IN A PLANE WHICH COMMENCES IN THE BOTTOM ADJACENT THE HEEL END AND WHICH EXTENDS FORWARDLY SUBSTANTIALLY PARALLEL TO A PLANE TANGENT TO THE MOST REARWARDLY CONVEX PART OF THE BACK LINE OF THE BACK PART, SAID FOREPART BEING MOVABLE REARWARDLY RELATIVE TO THE BACK PART, MEANS PIVOTALLY CONNECTING THE PARTS, SAID MEANS BEING OPERABLE TO EFFECT MOVEMENT OF THE FOREPART FROM A POSITION IN WHICH THE BOTTOM PORTION OF THE FOREPART IS IN ALIGNMENT WITH THE BOTTOM PORTION OF THE BACK PART TO A POSITION IN WHICH IT IS DISPLACED UPWARDLY THEREFROM, A PART EXTENDING REARWARDLY FROM THE FOREPART, SAID PART HAVING A SURFACE IN THE PLANE OF THE BOTTOM, SAID BACK PART CONTAINING A RECESS WITHIN WHICH SAID PART IS ADAPTED TO NEST WITH ITS SURFACE IN THE PLANE OF THE BOTTOM OF THE BACK PART WHEN THE FOREPART AND BACK ARE IN ALIGNMENT AND FROM WHICH IT IS ELEVATED WHEN THE FOREPART IS ELEVATED TO SHORTEN THE LAST, SAID PART OVERLYING THE UPPER EXTREMITIES OF THE CONFORNTING FACES OF THE BEARING SURFACES.