US3284826A - Hinged last - Google Patents

Description

Nov. 15, 1966 w. L- McNEILL ETAL 3,284,826

HINGED LAST Filed Dec. 16, 1965 INVENTOR. WARREN l MCNEILL Y WALTER l. McNElLL KW r fiddled ATTORNEYS United States Patent 3,284,826 HINGE!) LAST Warren L. McNeill, 20 Johnson Road, and Walter L McNeil], 3 Richard St., both of Saugus, Mass. Filed Dec. 16, 1965, Ser. No. 516,834 6 Claims. (Cl. 12136) This application is a continuation-in-part of application Serial No. 474,677 filed July 26, 1965, and now abandoned.

This invention relates to hinged lasts and particularly to a last incorporating an improved hinge assembly constructed to perform the usual functions of keeping the toe and heel parts of the last together and of maintaining the last in either open or closed position. More specifically, this invention is an improvement of the invention disclosed in United States Letters Patent 2,712,664 issued July 12, 1955.

Many lasts, as heretofore constructed, can be improved from the standpoint of durability and operation under the extreme pressures encountered in the levelling, sole pressing, and cement Sole attaching operations, during which the lasts tend to open because of these extreme pressures, thus leading to defectivve end products. Also, in some instances, the pressures involved may cause a breakage of the heel and toe parts unless provision is made to bias the last parts together resiliently in their closed positions. On the other hand, if the heel and toe parts are held together in the closed position too strongly, then it becomes difiicult to open the last for the removal thereof from the shoe, and because of this difficulty again rupture of the toe and heel parts may appear because of the forces encountered.

These problems are particularly acute in the use of lasts made of molded plastics. The plastics used for shoe lasts today do not resist too Well compressive pressures which are very high. In such a last, if too great a force is applied to the pins during use of the last, that is, the force of too strong a linkage mechanism, particularly as the last parts over-center on opening and closing, this force will cause the pins to compress the last plastic beyond its resilient strength, with the result that the pins are from then on too close together, and the last is virtually useless.

On the other hand, if the hinge structure is made sof enough to overcome this problem, then that same sof hinge will permit the last toe and heel parts to separate too much beyond the normal closed position, with two adverse results: One, too great a separation will cause defective products; and two, the hinge itself will be strained beyond its yield point, thus taking a permanent set. In either case, the last is or becomes useless for satisfactory shoe-making operations.

Among the several objects of the invention therefore, may be noted the provision of a more durable and eflicient last employing a novel hinge assembly which requires a minimum amount of Working space in the interior of the toe and heel parts and yet which securely holds the parts resiliently together beyond use tolerances against extreme pressures encountered during the aforementioned shoemaking operations; the provision of a hinge assembly which can be made in only two parts, thus leading to a smaller space to be occupied by the whole hinge assembly with enhanced strength of the toe and heel parts; the provision of a novel hinge linkage structure which provides one force adapted to hold the toe and heel parts together for opening and closing operations of the last, and yet which provides an additional force which comes to play if the last parts tend to separate more than an acceptable amount beyond the normally closed position under the pressures encountered during the above mentioned shoemaking operations; the provision of a last of "ice the last-named class incorporating a hinge structure which is relatively easy to open and close; the provision of parts for a last hinge assembly which may be stamped out of sheet metal; and the provision of a linkage construction for the heel and toe parts of a last, which is readily adaptable to economic manufacture, ease of use, and is long wearing and durable. Other objects and advantages of this invention will be in part obvious and in part pointed out hereinafter.

The invention accordingly comprises the elements and the combinations of elements, features of construction, and arrangement of parts which will be exemplified in the structures hereinafter described, and the scope of the application of which will be indicated in the following claims.

In the accompanying drawings in which are illustrated two embodiments of the invention:

FIG. 1 is a side view, partly in section, of a shoe last shown in the closed position;

FIG. 2 is a cross-sectional view of a portion of the FIG. 1 embodiment, given to show the interior assembly of the last hinge, and taken in the direction of sight lines 2-2 on FIG. 1;

FIG. 3 is an enlarged view of a hinge member used in the FIG. 1 embodiment;

FIG. 4 is a side View of a cooperating link member used in the FIG. 1 embodiment;

FIG. 5 is a side view of a difierent link member, similar in some respects to the FIG. 4 link member; and

FIG. 6 is a side view, partly in section, given to illustrate a last which has separated adversely beyond the normally closed position of the last.

Throughout the drawings, similar reference characters illustrate corresponding parts of the embodiments. The various drawings in some instances have been exaggerated as to relative thickness of the parts, in order to show detail with greater clarity.

Turning now to FIG. 1 for a further description of the invention, there is shown a last having a toe part 2 and a heel part 4. If desired, the heel part 4 may be provided with the usual comb plate, and both parts may be provided with a metal plate secured to the bottoms of the last parts. However, such additional features are not part of this invention.

The heel part 4 is provided, in customary manner, at its forward end with a hinge projection 6 of circular contour which extends transversely across the front of the heel part. The toe part is provided at its rear end with a transverse concave depression 8 into which the projection 6 fits closely so that the parts 2 and 4 may be relatively rotated upon the line 10 as an axis.

The heel part 4 is bored to receive anchor pin 12, and the toe part 2 is similarly provided with anchor pin 14, both pins being conventional types. The pins 12 and 14 are so located that when the last is collapsed, a line connecting their centers falls to one side of the axis of rotation represented by line 10, and when the last is closed, the center-connecting line lies on the other side of the axis of rotation.

It will be noted that due to the relative rotation of the toe and heel par-ts about the center of rotation 10, the separation of the pins is less when the line joining the centers of the pins is on either side of the center of rotation than is the case when the line intersects said center. If, now, too rigid a force is exerted on the pins in order to hold the toe and heel parts in their normal closed position, then because of the necessary further separation of the pins that takes place when it is attempted to move the toe and heel parts past the center of rotation (in either direction) this too rigid force will make it very difficult, if not impossible, so to move the toe and heel parts. If they should be forced past the over-center position in 3 such a case, in all probability the last will either break, or the pins will be driven into the last material such a distance as to make the last useless thereafter. This ex planation is given to clarify the reason for the particular dimensions of the hinge and link members now to be described.

The anchor pins 12 and 14 are connected by a hinge member 16 (hereinafter called a hinge) and by member 18 (hereinafter called a link or link member). Each of hinge 16 and link 18 may be stamped from any tough resilient metal such as spring steel. Alternatively, hinge 16 and link 18 can be molded or formed from a tough resilient plastic such as one of the polyamides, nylon for example. The hinge 16 comprises a pair of spaced apart elongated side members or glands 20 and 22 smoothly merging at their terminal portions into a pair of rounded ends 24 and 26.

The side members 20 and 22 are of substantially the same width but are otherwise of different configuration. The side member 20 is slightly curved while the member 22 defines a pronounced curve rendering the gap between said members non-uniform in width. Interconnecting the intermediate portion of each of the side members is a rib 28 which divides the space defined by the side members and ends into two similar slots 30 and 32. The slots 30 and 32 are circumferentially spaced by the rib 28 and are of arcuate configuration due to the curvatures of the side members 20 and 22. Additional details of construction of the hinge 16 and the further advantages thereof are fully set forth in the aforementioned United States Patent 2,712,664 and will not be given in further detail here.

The link 18 is provided with the sides 34 and 36 of unequal curvature so that the link is narrower at its center portion 38 than at the ends. Holes 40 and 42 are provided at the ends of link 18, as shown, and these holes are bordered or defined by the peripheral end portions or terminal portions 44 and 46 of the link. It will be noted that the holes 41 and 42 are larger in diameter than the pins 12 and 14, the latter being drawn in dotted lines in FIG. 4 to show this difference. Holes 40 and 42 can be, of course, other than round, such as oval or elliptical, for example, the important feature being the spacing between the inner peripheral edges 48 and of the end portions 44 and 46. This spacing is so made that when the toe and heel parts are in such position that a line connecting the centers of pins 12 and 14 intersects the center of rotation 10, the inner peripheral edges 48 and 50 of the end portions 44 and 46 respectively just touch the outer peripheries of the pins 12 and 14, respectively. This means, of course, that when the last is in its normal closed position, these inner peripheral edges will be separated from their respective pins by a few thousandths of an inch, this separation hereinafter being sometimes referred to as lost motion. In practice, as measured on successful samples of lasts embodying this invention, this separation was fiveto seven-thousandths of an inch at each pin.

The operation of the device will now be described, as follows:

FIG. 1 shows the last in its normally closed position, and it will he noted that in this position, the hinge 16 has been lengthened, that is, strained beyond its normal unstressed configuration, all as has been set forth in said Patent 2,712,664. The function, therefore, of hinge 16 is to hold the toe and heel parts securely together in the normally closed position of the last in ordinary uses of the last. That is, the hinge 16 is resiliently biased by the closing action to pull pins 12 and 14 together.

It is also to be noted that in the normal closed position, the spacing of the inner edges 48 and 50 of the peripheral end portions 44 and 46 of the link 18 is such that these edges do not rest against the outer peripheries of the respective pins 12 and 14 (as explained above) so that the link 18 is in an unstrained and unstressed state when the last is in its normal closed position. However, should the last tend to open further as shown (in exaggerated manner) in FIG. 6 by forces encountered during shoe covering operations (these forces acting in the direction of arrows 52 and 54), the aforementioned separation or lost motion will be taken up, and the restraining force of the link 18 will then immediately after this come into play to prevent further motion of the toe and heel parts. The amount of separation or lost motion is within the tolerances permitted in the use of the last. The effect of link 18 is also to prevent the hinge 16 from being strained so far as to go beyond the yield point of the metal of which it is made.

On collapsing the last to remove it from the shoe, and on closing it, the toe and heel parts have an over-centering action (as explained above), due to the relationship of the pin centers to the axis of rotation 10. During this over-centering operation, it is only the hinge 16 which is effective, because link 18 does not come into play. This leads to a last which is easier to operate than former such devices where the hinge alone must be strong enough to resist more than a permissible amount of motion of the last par-ts beyond the normal closed position.

In FIG. 6, the configuration of the hinge 16 is shown by the dotted lines 56 and 58 when the last toe and heel parts are in their normal closed position, and the full lines show the configuration of the hinge when the last toe and heel parts have been separated the amount shown in FIG. 6, the link 18 being stressed but relatively unstrained. It is to be noted that .the separation shown in FIG. 6 has been exaggerated for reasons of clarity.

It has been noted above that in the over-center position of the last, the edges 48 and 50 of the terminal portions 44 and 46 just rest against the pins 12 and 14. By just rest is meant that the link 18 is in a substantially unstressed state, but it is intended that there can be a slight separation of the edges 48 and 50 from the outer peripheral portions of the pins 12 and 14, or the distance between these edges can be just slightly less than the distance between the outer peripheral portions of the pins so that the link 18 is slightly loaded. That is, it is intended that the link 18 do substantially no Work during collapsing of the last or closing it, and no work toward holding the last parts together when the last parts are in their normally closed position. It is intended that the link 18 begin to exert its effective additional force immediately after the above described permissible lost motion of the last parts in the direction beyond the normally closed position, is taken up, this force being additive, of course, to the force of the hinge which is already resisting unwanted motion.

Turning now to FIG. 5, there is shown an alternative embodiment of the link 18. In this instance, the alter native link 60 has an external configuration the same as the FIG. 4 link, has holes 62 and 64 as in the FIG. 4 link, and the inner edges 66 and 68 of peripheral end portions 70 and 72 of the link are spaced apart the same distance as has been described for the FIG. 4 link.

In this instance, however, the center portion 74 has been relieved by the arcuate slot 76. The purpose of the arcuate slot is to make the link as a whole more resilient than is the case in the FIG. 4 link, and thus to provide a link which exerts less additive restraining force on the heel and toe parts, while still beginning to exert that force the moment the aforesaid lost motion is taken up.

In the drawings, there is shown one hinge and one link in face to face relationship in the last. Since the hinge 16 is the one that will exert the necessary forces for the normal operations of the last, and the link 18 is used to exert its force to minimize or eliminate completely any adverse opening motions of the last beyond a permissible amount, the hinge 16 may be made thicker than the link 18. Of course, it is within the scope of this invention to use two or more of the hinges 16 and a plurality of the links 18 if it is so desired to obtain additional operating forces for the last.

In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained.

As many changes could be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description, or shown in the accompanying drawings, shall be interpreted as illustrative and not in a limiting sense.

Having thus described our invention, what we claim as new and desire to secure by letters Patent of the United States is:

1. A last comprising heel and toe parts having interfitting curved surfaces shaped to perm-it relative rotation of the parts about a fixed axis from a normally open position to a normally closed position, a last hinge of resilient fiat material and being provided with a pair of apertures, one at each end thereof, said hinge being capable of being resiliently strained to increase the distance between said apertures; a link of resilient fiat material lying against said hinge and also being provided with a pair of openings, one at each end thereof, each opening being bounded in part by a peripheral end portion of said link, said link also being capable of being resiliently strained to increase the linear distance between said openings; and a pair of anchor pins disposed transversely in said toe and heel parts and passing through said apertures and said openings, said pins being so located that in either of their normal positions a line passing through their centers falls aside the axis of rotation of the last parts, and the inner edge of each of said peripheral end portion rests upon the outermost peripheral portion of its respective pin when a line connecting the centers of said pins intersects said axis during relative rotation of the toe and heel parts of the last, but are free from the said outer peripheral portion of the respective pin when said wheel and toe parts are in their normal closed position, said link being without substantial strain at the position of said intersection.

2. The last of claim 1 in which each aperture in said hinge is bounded in part by a peripheral end portion of said hinge, and in which the linear distance between the inner edges of said peripheral end portions of said apertures of the hinge is less than the linear distance between the inner edges of said peripheral end portions of said link when the hinge and link are in an unstrained condition, but such distances are substantially the same when said hinge is in its strained condition as said line intersects said axis.

3. The last of claim 1 in which each of said hinge and link are arcuate in shape and said link is without substantial strain when said last is operated normally, but becomes strained when said toe and heel parts are moved a predetermined amount beyond their normal closed position, said link providing a force additional to that of said hinge to resist motion of said toe and heel portions beyond said predetermined amount.

4. The last of claim 1 in which said hinge has a pair of elongated side members of substantially equal width and unequal curvature separated by a gap, the gap separating said side members being larger at its ends than at its intermediate portion, a pair of end members interconnecting the side members, a rib intermediate the end members and connecting the side members whereby said side members, end members and rib form said gap into a pair of circu mfe rentially spaced arcuate slots, said slots constituting said apertures.

5. The last of claim 3 in which the peripheral end portions of the hinge and link are curved and the radius of curvature of the inner edge of each said peripheral end portion of said link is greater than the radius of curvature of the inner edge of the mating peripheral end portion of said hinge.

6. The last of claim 5 in which said link is provided with a third aperture intermediate the end apertures, whereby said link is made more resilient.

References Cited by the Examiner UNITED STATES PATENTS 1/1940 McNeill 12-l36 7/1955 McNeill 12136

Claims (1)

1. A LAST COMPRISING HEEL AND TOE PARTS HAVING INTERFITTING CURVED SURFACES SHAPED TO PERMIT RELATIVE ROTATION OF THE PARTS ABOUT A FIXED AXIS FROM A NORMALLY OPEN POSITION TO A NORMALLY CLOSED POSITION, A LAST HINGE OF RESILIENT FLAT MATERIAL AND BEING PROVIDED WITH A PAIR OF APERTURES, ONE AT EACH END THEREOF, SAID HINGE BEING CAPABLE OF BEING RESILIENTLY STRAINED TO INCREASE THE DISTANCE BETWEEN SAID APERTURES; A LINK OF RESILIENT FLAT MATERIAL LYING AGAINST SAID HINGE AND ALSO BEING PROVIDED WITH A PAIR OF OPENINGS, ONE AT EACH END THEREOF, EACH OPENING BEING BOUNDED IN PART BY A PERIPHERAL END PORTION OF SAID LINK, SAID LINK ALSO BEING CAPABLE OF BEING RESILIENTLY STRAINED TO INCREASE THE LINEAR DISTANCE BETWEEN SAID OPENINGS; AND A PAIR OF ANCHOR PINS DISPOSED TRANSVERSELY IN SAID TOE AND HEEL PARTS AND PASSING THROUGH SAID APERTURES AND SAID OPENINGS, SAID PINS BEING SO LOCATED THAT IN EITHER OF THEIR NORMAL POSITIONS A LINE PASSING THROUGH THEIR CENTERS FALLS ASIDE THE AXIS OF ROTATION OF THE LAST PARTS, AND THE INNER EDGE OF EACH OF SAID PERIPHERAL END PORTION RESTS UPON THE OUTERMOST PERIPHERAL PORTION OF ITS RESPECTIVE PIN WHEN A LINE CONNECTING THE CENTERS OF SAID PINS INTERSECTS SAID AXIS DURING RELATIVE ROTATION OF THE TOE AND HEEL PARTS OF THE LAST, BUT ARE FREE FROM THE SAID OUTER PERIPHERAL PORTION OF THE RESPECTIVE PIN WHEN SAID WHEEL AND TOE PARTS ARE IN THEIR NORMAL CLOSED POSITION, SAID LINK BEING WITHOUT SUBSTANTIAL STRAIN AT THE POSITION OF SAID INTERSECTION.

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