US2341715A - Masking apparatus - Google Patents

Description

Feb-15, 1944.v Y v, F. HAFgRlNGToN Y 2,341,715

MASKING APPARATUS Filed March 412, 1943 Patented Feb. 15, 1944 MIASKKNG APPARATUS Valentine F. Harrington, Newton, Mass., assignor to United Shoe Machinery Corporation, Flemington, N. J., a corporation of New Jersey Application March 12, 1943, Serial No. .478,905

14 Claims.

This invention relates to apparatus for use in coating heels of shoes and is herein illustrated as embodied in a device for use in protecting the upper at the back part of the shoe during the application of a coating to the heel which has been previously attached thereto.

In one method of shoe manufacture the heel is attached to the shoe and thereafter it is trimmed to the desired dimension, scoured and coated with blacking or lacquer. Since the coating material is a thin liquid, it is diicult to control and while it is being applied to the heel it may spatter or run onto the upper. It is especially dilcult to confine the coating liquid solely to the surface of the heel when it is applied with a spray gun. l

In view of these diiiiculties, an object of the present invention is to provide an apparatus which, while simple and inexpensive, will eiectively protect the upper at the back part of a shoe during the application of a coating to the heel, the apparatus being so constructed and operated that it is adapted to accommodate substantially any shoe, regardless of its size, and is substantially self -cleaning In the accomplishment of this object, a feature of the invention resides in a novel mechanism for wrapping a flexible masking sheet about the 'upper at the back part of a shoe to protect it during the application of the coating tothe heel by controlled relative movement between the shoe and sheet supporting means. The latter is constructed and arranged initially to hold the sheet ltaut while the shoeis located with respect thereto and thereafter during' the relative movement i to draw and to guide the edge of the sheet into the heel crease, the sheet supporting vmeans in co-operation with the sheet serving to support the shoe. In the illustrated device, the corners of the sheet are attached to the forward ends of a pair of spaced arms which are mounted for movement to and from each other, means being provided for yieldably urgingthe arms together and treadle-operated means being provided for separating the arms, thereby initially to hold the upper edge of the sheet taut so that the edge of the sheet may be located in the heelv crease at the `back of the shoe adjacent to the backseam. Having been located with respect to the sheet, the shoe is moved rearwardly with respect to the forward ends of the arms and simultaneously the arms are allowed to move inwardly toward theopposite sides of the shoe. The aforesaid treadle-.operated means is adapted to control the inward movement of the arms during the relative movement between the shoe and the arms to cause the upper edge of the sheet progressively to vbe drawn, while under tension, into the heel crease along the sides of the heel and, finally, to permit the forward ends of the arms to engage the opposite sides of the shank of the shoe far enough in advance of the heel to take up the entire length of the sheet irrespective of the circumferential length of the heel crease. The grip afforded by yieldable engagement of the forward ends of the arms with the opposite sides of the shank is suicient, in cooperation with/the sheet, to support the shoe.

The details of the invention will now be described with reference to the accompanying drawing, in which Fig. -1 is a perspective View of an apparatus in which the invention is embodied, the parts being shown in their operative positions With a shoe in the machine;

Figs. 2 and 3 illustrate the relative positions of the shoe and sheet supporting means at initial and intermediate stages in wrapping the sheet about the upper at the back part of the shoe; yand Figs. 4, l5 and 6 show three special forms which may be employed at the upper edge of the flexible sheet to insure a close fit around the heel crease. i

As illustrated herein, the apparatus comprises a iiexible sheet lll (Fig. v2) and means l2 (Fig. 1) for supporting the sheet in a position to be wrapped about Vthe upper at the back part of a shoe S by controlled relative movement between the shoe and the supporting means, the latter serving also, in combination with the sheet, to support the shoe,'heel uppermost, during the application cf a coating material to the surface of the heel.

The supporting means l2, which is arranged to hold the sheet it, comprises a pair of horizontally disposed spaced arms Hl having in wardly directed forward ends I6 to which the corners of .the sheet are atttached. -As illustrated in Fig. 2, the forward ends i6 of the arms I-ll are bifurcated ati8 and the corners of the sheet are drawn into the bifurcationsand clamped in place by screws 2t. The sheet hangs vertically downward from the arms and, as a preliminary step to wrapping the sheet about the upper at the back part of the shoe, the shoe is placed heel uppermost with the rear of its back part against the center of the sheet so that .the Vedge 22 of the sheet engages the heel crease adjacent to the backseam, as illustrated in Fig. 2. To facilitate locating the edge 22 of the sheet in the heel crease, it is desirable to hold the edge taut. Accordingly, the arms I4, from the forward ends l of which the sheet is suspended, are pivotally mounted at 24 between their ends at the opposite ends of a horizontal bar 28 for rotational movement to and from each other in a horizontal plane. The bar 26 is formed integral with the upper end of a column 2B which rises vertically from a base 36. By spreading the forward ends I6 of the arms, the edge of the sheet may be held taut. To this end, a cable 32 is attached to the rear end of each arm I4 and passes inwardly over a pulley 34 and downwardly toward the base where it is attached by means of a clamping plate 36 to a head 38 formed at the upper end of a treadle rod 40. The ends of the cables are attached to the rear ends of the arms I4 by passing them through openings 42 formed in studs 44 fixed to the arms and by binding them in place with setscrews 46. The pulleys 34 are mounted to turn on a horizontal spindle 48 threaded into a boss 56 extending rearwardly from the bar 26. The treadle rod 46 extends downwardly toward the base and is connected to a treadle 52, as illustrated. By downward movement of the treadle 52, the rear ends of the arms I4 may be drawn toward each other and this, in turn, spreads the forward ends of the arms so that the sheet is stretched tautly between them. To prevent stretching the upper edge of the sheet more than is necessary and to ypermit 'variation in the separation of the arms lin accordance with the length of the sheet, the treadle rod 46 is passed through an opening 54 in a rearwardly extending arm 56 formed on the column 28. Surrounding the rod 4i) is a sleeve 58 threaded through the opening 54. A knurled head 60 on the sleeve 58 affords means for adjusting the heightwise position of the sleeve and a knurled nut 62 threaded on the sleeve provides means for locking the sleeve in a selected position. The downward movement of the treadle rod 40 is limited by` I4, and consequently the corners of the sheet,

are permitted to move inwardly toward the opposite sides of the shoe, the relative movement Nbetween the shoe and the forward ends of the arms being controlled so that the edge of the sheet is maintained under tension and progressively is drawn into the heel crease along the opposite sides of the shoe. It is to be observed that, to insure entrance of the edge 22 into the heel crease, the shoe, during its rearward movementwith respect to the forward ends of the arms, must be held so that the plane of the heel crease is horizontal and passes through the horizontal upper edge 22 of the sheet. The inward movement of the forward ends of the arms I4 is produced by a compression spring 64 disposed between the arms behind the bar 26. To

hold the spring 64 in place and to force the arms apart, the spring is placed upon a rod 66 the opposite ends of which pass through abutments 68 fixed to the arms. The ends of the spring 64 bear against the abutments. Washers and cotters 'Ill at the ends of the rod 66 retain it in place. The control of the inward movement of the forward ends of the arms is effected by the treadle 52, treadle rod 40 and cables 32, which enable the operator to restrain such movement against the action of the spring 64.

Since the control afforded by the treadle mechanism permits the operator. to bring the forward ends of the arms, and consequently the corners of the sheet, into engagement with the opposite sides of the shoe at will, it is evident that the device may be employed for protecting any shoe regardless of its size if the sheet I0 is made long enough from corner to corner to extend about the circumferential length of the heel seat of the largest shoe expected to be encountered. That is, when a shoe smaller than the largest that the device will accommodate is to be protected by wrapping the sheet about its back part, the shoe is thrust rearwardly to maintain the edge 22 taut. Then, as the for; ward ends of the arms are moved inwardly toward the opposite sides ofthe shoe, they are brought into engagement with the shank of the shoe far enough in advance of the heel to take up the extra length. Since the shank tapers from heel to ball, the sheet will be drawn inward forwardly of the heel (Fig. 1) and thus the edge of the sheet will snugly t the neel crease-at the breast edges of the heel where it merges into the shank. I

The forward ends I6 of the arms I4 are yieldably held against the opposite sides of the shank portion of the shoe by the spring 64 when the sheet has been drawn completely about the back part of the shoe and, together with the sheet, support the shoe. It is to be observed thatthe end of each arm is ared at 12 and that the end face of the ared portion is provided with a groove 'I4 (Fig. 3). Thus, when the forward ends of the arms are brought into engagement with the shank, the flared grooved end surfaces will engagethe shank portion of the sole and afford a secure grip on the shank of the shoe. Supporting the shoe in this manner facilitates the coating operation since the operator has both hands free for handling and operating the spraying equipment.

The sheet I0 may be composed of various materials. However, in the preferred form it is composed of rubber, or a synthetic rubber-like material, because the elasticity of the rubber sheet enables it to stretch and conform to the outward bulge of the upper adjacent to the heel crease,-

especially along the backseam, and at the same time to retain a close t around the heel crease. Moreover, since the rubber sheet'tends closely to hug the upper, it provides considerable support for the shoe. Another important advantage'is that the rubber sheet, as employed herein, is self-cleaning. This is brought about by the fact that the sheet is alternately stretched and allowed to contract from its stretched condition. Since the stainor lacquer `applied to the heel is quick-drying and relatively inelastic, any that runs down onto the sheet will dryquickly and flake off as soon as the dimensions of the sheet change, either by expansion or contraction. It is evident, therefore, that in the operation of the appara-tus the sheet is practically self-cleaning. During the application of the coating, whenthe sheet is wrapped about the back part of the shoe, it is under tension. Consequently, when the arms I4 are moved away from each other against 'the action of they spring fillandthe shoes Withdrawn, the sheet contracts, thus reducing its area and causingA the dried coating to ake olf. Immediately thereafter, the sheet is again stretched. as the arms are movedto their outmost position to tension the upper edge in readiness for the next operation', so thatv any remaining coating not flaked off by the contraction of the sheet is caused to flake off.

As illustrated in Figs. l, 2 and 3, the upper edge 22 of the sheet l0 is substantially square. However, to facilitate locating the edge with respect to the heel crease and its entrance into the heel crease, and to provide a seal so that none of the coating will leak by the edge to the underside of the sheet and thus soil the upper, the edge may be given a special formation.

In one-form, as illustrated in 4, a lip 'I6 is formed adjacent to the edge the upper surface TB of which is a continuation of the end edge face ofthe sheet and the under surface ll of which is shaped to conform to the contour of the shoe upper adjacent to the heel crease. When the sheet having a lip of this character is held taut between the arms I4 the apex A82 of the lip formed by the intersection of the upper and under surfaces 'I3 and 8G will serve as a positive means for locating the shoe in its proper heightwise position since when the rear of the shoe is moved into engagement with the lip it will enter the heel crease` As the sheet is drawn inwardly about the back part of the shoe by relative movement between the shoe and the arms, the lip will progressively guide itself into the heel crease, formingin its operative position a substantially horseshoe-shaped, inwardly directed rim from which the lower portion of the sheet hangs about the upper (Fig. l). It is to be observed that the entrance of the lip into the heel crease prevents displacement of the edge, and consequently of the sheet, upwardly or downwardly, and that the extra thickness provided at the edge strengthens it at a point Where it will receive the most wear and gives it a greater resistance to stretch than the lower portion of the shet.

In another form (Fig. 5), a binding member 84 is attached to the sheet ID adjacent to the upper edge. Preferably7 adhesive is employed for attaching the binding member to the sheet. lThe diameter of the binding member should be small enough to permit its ready entrance into the heel crease and, like the lip hereinbefore described= it will serve to locate the edge of the sheet at the heel crease, guide the edge during the relative movement of the shoe and the arms to insure its entrance into the heel crease, prevent relative movement between the edge of the sheet and the upper, and strengthen the edge of the sheet. The binding member 84 may be of rubber or a textile cord. The entrance of the binding member into the heel crease may be facilitated by coating it with talc so that it will slide easily along the surface of the upper. Whether the binding member is rubber or textile cord, its ends are attached with the corners of the sheet to the forward ends of the arms, as heretofore described. A textile cord is preferable because by exerting a positive.

pull on its ends the edge of the sheet may be drawn into the heel crease without depending upon the elasticity of the sheet which becomes slack with lo-ng use.

In a third form (Fig. 6) a textile binding member SS is molded into the upper edge of a sheet having a lip 88, similar to that shown in Fig. 4, running along one side adjacent to the upper edge. In thisform the advantages of having a lip which 'lits into the heel crease andconforms to the upper and an, inelastic binding member Which will insure entrance of the lip into the heel crease even after the sheet has lost considerable of itselasticity are combined.

AIn operation, the treadle 52 is depressed to spread the forward ends I6 of the arms I4, thereby to hold the upper edge 22 of the sheet I0 taut, and then a shoe is picked up and placed heel uppermost against the taut edge midway between its corners (Fig. 2), the shoe being adjusted'heightwise tocause the upper edge of the sheet to enter the heel crease adjacent to the backseam. Thereafter, the shoe is moved rearwardly andsimultaneously the treadle 52 is a1- lowed to rise, this in turn allowing the spring 64 to force the forward ends I6 of the arms I4 inwardly (Fig. 3), the movement of the shoe and the. rise of the treadle 52 being so controlled and timed that the upper' edgeV 22 of the sheet Il) is constantly maintained taut and is` progres,- sively drawninto the heel crease. Depending upon the circumferential length of the heel crease of the particular shoe being operated upon, the corners of the sheet Will be brought into engagement with the opposite sides of the shoe some.- where along the shank (Fig. 1), the forward ends It of the arms being yieldably held in engagement with the opposite sides of the shank by the spring 6d. The support afforded by the forward flared ends ofv the arms, together with that afforded by the contact between the sheet and the surface of the upper, is sufcient to hold the shoe so that the operator is free to use both hands to manipulate the heel coating apparatus. After the heel has been coated, the treadle 52 is depressed, thereby separating the arms I4, and the shoe is removed. During the initial separation when the shoe is removed, the sheet, which has been tensioned about the upper, contracts. During the final separation, that is, the movement of the forward ends of the arms into a position for the next operation, the sheet is again tensioned. Thus, any coating material which may have been deposited on the sheet will be caused to flake off.

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

1. Apparatus for protecting the shoe upper at the back part of a shoe during the application of a coating tothe surface of the heel, comprising a flexible sheet adapted to cover the rear end of a shoe upper, means for supporting the sheet at its opposite corners, means for urging said supporting means toward each other, and means for initially holding said supporting means separated to maintain the edge of the sheet between said corners taut so that the rear part of the shoe may be brought into engagement with the sheet to locate the edge of the sheet in the heel crease, said means for holding the supporting means separated being adapted to control the movement of said supporting means toward each other as the shoe is moved ,rearwardly with respect to the supporting means to cause the edge of the sheet while under tension progressively to enter the heel crease from the rear of the heel to the breast edges, said supporting means being adapted to engage the shank of the shoe toewardly of the breast edges and in coeration with the sheet to support the shoe for the the coating operation.

2. Apparatus for protecting the shoe upper at the back part of a shoe during the application of a coating to the surface of the. heel, comprising al flexible sheet, means for supporting thev sheet at its corners, means for urging said supporting means toward each other, means for holding said supporting means separated to maintain the edge of the sheet between said corners taut, said sheet having means adjacent to said edge adapted to enter the heel crease when the rear part of the shoe is brought into engagement with the sheet to locate the shoe heightwise with respect to said edge and to prevent relative movement between the edge and the shoe, and means for controlling the movement of said supporting means toward each other as the shoe is moved rearwardly with respect to the supporting means to cause said means adjacent to the edge of the sheet while under tension progressively to enter 'the heel crease from the rear of the heel to the breast edges, said supporting means being adapted to engage the shank of the shoe forwardly of the breast edges and in co-operation with the sheet to support the shoe for the coating operation.

3. Apparatus for protecting the shoe upper at the back part of a shoe during the application of a coating to the surface of the heel, comprising a flexible sheet, means for supporting the sheet at its opposite corners, means for urging said supporting means toward each other, means for holding the supporting means separated to maintain the edge of the sheet between said corners4 taut, said sheet having a lip adjacent to said edge adapted to enter the heel crease when the rear part of the shoe is brought into engagement with the sheet to locate the shoe heightwise with respect to the edge of the sheet, and means for controlling the movement of said supporting means toward each other as the shoe is moved rearwardly with respect to the supporting means to cause the lip while under tension progressively to enter the heel crease from the rear of the heel to the breast edges, said supporting means being adapted to engage the -shank of the shoe forwardly of the breast edges and in co-operation with the sheet to support the shoe for the coating operation.

4. Apparatus for protecting the shoe upper at the back part of a shoe during the aplication of a coating to the surface of the heel, comprising a iiexible sheet, means for supporting the sheet at its opposite corners, means for urging said supporting means toward each other, means for holding the supporting means separated to maintain the edge of the sheet between said corners taut, said sheet having a lip adjacent to its edge adapted to enter the heel crease when the rear part of the shoe is brought into engagement with the sheet to locate the shoe heightwise with respect to the edge of the sheet, an inelastic cord molded into said lip, and means for controlling the movement of said supporting means toward each other as the shoe is moved rearwardly with respect to the supporting means to cause the lip while under tension progressively to enter the heel crease from the edge of the heel to the breast edges, said supporting means being adapted to engage the shank of the shoe forwardly of the breast edges and in co-operation with the sheet to support the shoe for the coating operation.

5. Apparatus for protecting the shoe upper of the back part of a shoe during the application of a coating to the surface of the heel, comprising a flexible sheet, means for supporting the sheet at its oppositel corners, means for urging said supporting means toward each other, means for holding the supporting means separated to maintain the edge of the sheet between said corners taut, a lip adjacent to said edge, said lip having an upper surface forming a continuation of the end edge face and an under surface conforming substantially to the contour of the upper of a shoe adjacent to the heel crease, the apex formed by the intersection of said surfaces being adapted to enter the heel crease when the rear part of the shoe is brought into engagement with the sheet to locate the shoe heightwise with respect to the edge of the sheet, and means for controlling the movement of said supporting means toward each other as the shoe is moved rearwardly with respect to the supporting means to cause the lip while under tension progressively to enter the heel crease from the rear of the heel to the breast edges, said supporting means being adapted to engage the shank of the shoe forwardly of the breast edges and in co-operation with the sheet to support the shoe for 'the coating operation.

6. Apparatus for protecting the shoe upper at the back part of a shoe during the application of a coating to the surface of the heel, comprisng a flexible sheet, means for supporting the sheet at its opposite corners, means for urging said supporting means toward each other, means for holding the supporting means separated to maintain the edge of the sheet between said corners taut, said edge having a binding member attached to its inner side adapted to iit into the heel crease, said binding member being talcked so that when the rear part of the shoe is brought into engagement with the sheet to locate the binding member at the edge of the sheet in the heel crease the binding member will slide readily with respect to the surface of the upper, and means for controlling the movement of said supporting means toward each other as the shoe is moved rearwardly with respect to the supporting means to cause the binding member while under tension progressively to enter the heel crease from the rear of the heel to the breast edges,

said supporting means being adapted to engage the shank of the shoe forwardly of the breast edges and in co-operation with the sheet to support the shoe for the coating operation.

'7. Apparatus for protecting the shoe upper at the back part of a shoe during the application of a coating to the surface of the heel, comprising a flexible sheet, spaced supports to which the corners of the sheet are attached, said supports being movable toward and from each other, means for urging said supports toward each other, and means for initially holding said supports separated to maintain the edge of the sheet between said corners taut so that the rear part of the shoe may be brought into engagement with the sheet to locate the edge of the sheet in the heel crease, said means for holding the supports separated being adapted to control the movement of said supports toward each other as the shoe is moved rearwardly with respect thereto to cause the edge of the sheet while under tension progressively to enter the heel crease from the rear of the heel to the breast edges, said supports being adapted to engage the shank of the shoe forwardly of the breast edges and in co-operation with the sheet to support the shoe for the coating operation.

8. Apparatus for protecting the shoe upper at the back part of a shoe during the application of a coating to the surface of the heel.

comprising a flexible sheet, means for supporting the sheet at its opposite corners, said means being movable toward and from each other, a spring for urging said supporting means toward each other, and means for initially holding said supporting means separated to maintain the edge of the sheet between said corners taut so that the rear part of the sho-e may be brought into engagement with the sheet to locate the edge thereof in the heel crease, said means for holding the supporting means separated being adapted to control the movement of said supporting means toward each other as the shoe is moved rearwardly with respect to the supporting means to cause the edge of the sheet while under tension progressively to enter the heel crease from the rear of the heel to the breast edges, said supporting mans being adapted to engage the shank of the shoe forwardly of the breast edges and in co-operation with the sheet to support the shoe for the coating operation.

9. Apparatus for protecting the shoe upper at the back part of a shoe during the application of a coating to the surface of the heel, comprising a flexible sheet, means for supporting the sheet at its opposite corners, said supporting means being movable toward and from each other, means for urging said supporting means toward each other, and treadle-operated means for holding said supporting means separated to maintain the edge of the sheet between said corners taut so that the rear part of the shoe may be brought into engagement with the sheet to locate the edge of the sheet in the heel crease, said treadle-operated means being adapted to control the movement of said supporting means toward each other as the shoe is moved rearwardly with respect thereto to cause the edge of the sheet while under tension progressively to enter the heel crease from the rear of the heel to the breast edges, said supporting means being adapted to engage the shank of the shoe forwardly of the breast edges and in co-operation with the sheet to support the shoe for the coating operation.

10. Apparatus for protecting the upper at the back part of a shoe during the application of a coating to the surface of the heel, comprising a ilexible sheet, means for supporting the sheet at its opposite corners, said supporting means being movable toward and from each other, means for urging said supporting means toward each other, and means for initially holding said supporting means separated to maintain the edge between said corners taut so that the rear part of the shoe may be brought into engagement with the sheet to locate the edge'of the sheet in the heel crease, said last-named means comprising flexible cables attached to said supporting means, and a treadle connected to said cables operable to control the movement of said supporting means toward each other as the shoe is moved rearwardly with respect thereto to cause the edge of the sheet while under tension progressively to enter the heel crease from the rear of the heel to the breast edges, said supporting means being adapted "to engage the shank of the shoe forwardly of the breast edges and in co-operation with the sheet vto support the shoe for the coating operation.

11. Apparatus for protecting the shoe upper at the back part of a shoe during the application of a coating to the surface of the heel, comprising a flexible sheet, spaced supports to which the corners of the sheet are attached, said supports being movable toward and from each other, a spring for urging said supports toward each other, and treadle-operated means for initially holding said supports separated to maintain the edge of the sheet between said corners taut so that the rear part of the shoe may be brought into engagement with the sheet to locate the edge of the sheet in the heel crease of the shoe, said treadle-operated means being adapted to control the movement of said supports toward each other to cause the edge of the sheet while under tension progressively to enter the heel crease from the rear of the heel to the breast line, said supports being adapted to engage the shank of the shoe forwardly of the breast line and in co-operation with the sheet to support the shoe for the coating operation.

l2. Apparatus for protecting the shoe upper at the back part of a shoe during the application of a coating to the surface of the heel, comprising a exible sheet, spacedarms to which the corners of the sheet are attached, said arms being movable toward and from each other, means for urging the arms toward each other, means for initially holding the arms separated to maintain the edge of the sheet between said corners taut so that the rear part of the shoe may be brought into engagement with the sheet to locate the edge of the sheet in the heel crease, said means for holding the arms separated being adapted to control the movement of said arms toward each other to cause the edge of the sheet while under tension progressively to enter the heel crease from the rear of the heel to the breast edgesand ared ends on said arms having grooves therein, the ared grooved ends of the arms being adapted to engage the opposite edges of the shank of the shoe sole forwardly of the breast edges and in co-operation with the sheet to support the shoe for the coating operation.

13. Apparatus for protecting the shoe upper at the back part of a shoe during the application of a coating to the surface of the heel, comprising a frame, a pair of spaced-apart arms pivoted between their ends upon the frame for movement to and from each other, a flexible sheet fastened at its corners between the forward ends of the arms, a spring disposed between the rear ends of the arms in a position to urge the arms to separate, and a pair of cables fastened to the rear ends of the arms, said cables being operable to draw the arms together in opposition to the spring, thereby to tension the sheet held between the forward ends of the arms.

14. Apparatus for protecting the shoe upper at the back part of a shoe during the application of a coating to the surface of the heel, comprising a frame, a pair of spaced-apart arms pivoted between their ends upon said frame for movement toward and from each other simultaneously, a exible sheet fastened at its corners between the forward ends of the arms, means disposed between the rear ends of the arms in a position to urge the forward ends of the arms together, means connected to the rear ends of the arms to separate the forward ends of the arms, thereby to tension the sheet between them, and adjustable means associated with said last-named means for variably limiting the extent of separation of the forward ends of the arms.

VALENTINE F. HARRINGTON.

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