String lasting apparatus

  • Inventors: WILBUR FISK
  • Assignees: Usm Corp
  • Publication Date: October 28, 1969
  • Publication Number: US-3474475-A

Abstract

Claims

W. FISK STRING LASTING APPARATUS 4 Sheets-Sheet 1 Filed March 4, 1968 By his At tome Mfifl Oct. 28; 1969 w. FISK 3,474,475 STRING LASTING APPARATUS Filed March 4, 1968 4 Sheets-Sheet 2 Oct. 28, 1969 w. FlSK 3,474,475 STRING LASTING APPARATUS Filed March 4, 1968 4 Sheets-Sheet 5 ,Fwa - Oct. 28, 1969 w. FISK 3,474,475 STRING LASTING APPARATUS Filed March 4, 1968 4 Sheets-Sheet 4. 3,474,475 STRING LASTING APPARATUS Wilbur Fisk, South Hamilton, Mass., assignor to USM Corporation, Flemington, N.J., a corporation of New Jersey Filed Mar. 4, 1968, Ser. No. 710,057 Int. Cl. A4311 /00 US. Cl. 12-79 9 Claims ABSTRACT OF THE DISCLOSURE Apparatus for providing power assistance in string lasting footwear uppers, the apparatus including two power operated mechanical arms which retain opposite ends of a lasting string and cooperate to pull the string taut, whereby to last an upper on a footform. The mechanical arms are provided with means for preventing snap-back upon accidental breakage of the lasting string. BACKGROUND OF THE INVENTION Field of the invention This invention relates to lasting devices and is directed more particularly to apparatus for string lasting footwear uppers. Description of the prior art In the manufacture of sneakers and other sports and casual wear shoes having fabric uppers, it is customary to string last the uppers onto footf-orms in preparation for the attaching of a sole and heel unit to the lasted upper. In performing the string lasting operation it is necessary that loose ends of a string sewn to the edge of the overlasted margin of the upper be pulled tightly to cause the upper margin to be drawn over the bottom of the footform. Generally, this operation is conducted manually and requires sufficient strength of the part of the operator so that, by and large, women are excluded from this area of shoe fabrication. In addition, the strings tend to cut the operators fingers, so much so that they must be taped prior to commencing the lasting operation. Because of the manual strength required and because of the cutting problem, the string lasting operation generally requires more than the normal amount of training. There have been attempts in the past to alleviate these problems by the use of mechanical arms which have been designed by grasp the ends of the string and pull the string taut. Such devices have generally been unsuccessful because of low production rate, high cost of equipment, or safety factors. Regarding the latter, a major safety problem common in prior attempts to mechanize string lasting was the faliure to provide means for protecting the operator in the event of breakage of the string. Mechanical arms for string lasting have in the past suffered from the short-comings of snapping back toward the operator after an accidental breakage of the lasting string. SUMMARY OF THE INVENTION It is an object of the present invention to provide power operated mechanism for string lasting which has means for preventing snap-back of parts of the mechanism toward the operator upon accidental breakage of a string. A further object of the invention is to make such apparatus relatively simple in operation, and therefore low in cost, but which can perform at a rate comparable to or better than manual operation. Still another object of the invention in providing such apparatus is to assure that mechanism rather than human hands draws the string taut which alleviates the necessity of strong hands, taped fingers, and extensive operator breaking-in. nited States Patent 0 3,474,475 Patented Oct. 28, 1969 With the above and other objects in view, as will hereinafter appear, the present invention contemplates as a feature thereof the provision of means for mounting a footform, mechanical arm means proximate to the footform mounting means, string retaining means on the arm means for retaining the ends of the string of an upper, power means for operating the arm means whereby to draw the string taut, and means for preventing snap-back of said arm means upon accidental breakage of the string. The invention is herein illustrated as embodied in mechanism which is mounted on a machine for the injection molding of sole and heel units onto lasted uppers. The present invention may, however, be used in connection with vulcanizing machines or as a separate unit which prepares the upper for receiving a cementedon sole. The above and other features of the invention, including various novel details of construction and combinations of parts, will now be more particularly described with reference to the accompanying drawings and pointed out in the claims. It will be understood that the particular device embodying the invention is shown by way of illustration only and not as a limitation of the invention. The principles and features of this invention may be employed in various and numerous embodiments without departing from the scope of the invention. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of one form of apparatus illustrative of an embodiment of the invention, shown attached to an injection sole molding machine and shown in position for receiving the free ends of the string sewn in an upper to be string lasted; FIG. 2 is similar to FIG. 1 but shows the apparatus in position upon completion of the string-pulling portion of a string lasting operation; FIG. 3 is a detail view of the string gripping means; FIG. 4 is a side elevational view of an arm means; FIG. 5 is a detail view of the snap-back prevention means; FIG. 6 is a diagrammatic illustration of one embodiment of a control means suitable for use in the apparatus; and FIG. 7 is a diagrammatic illustration of a second embodiment of a control means suitable for use in the apparatus. DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1, it will be seen that the illustrative device includes a base plate 2 which may, as illustrated in FIG. 1, be mounted on the turret 4 of an injection molding machine 6, or may be mounted on a vulcanizing machine, or may be used as an independent machine to prepare string lasted uppers for the injection molding of soles thereon, or for the vulcanization of soles thereon, or for otherwise attaching soles, as by adhesive. A footform 8 is attached to the base plate 2 in any appropriate manner, as by an interconnecting footform mounting member 10 which is releasably connected to the footform 8 and also releasably connected to the base plate 2 by bolts 12 which retain a flange portion 14 of the footform mounting member 10. A mounting block 16 is fixed to a frame member 18, and has projecting from either side thereof mounting pins 20 on which are rotatably mounted a pair of arms 22. Each arm 22 may be provided with a cylindrical portion 24 for mounting on the mounting pins 20. Mounted on the frame member 18 is a cylinder support member 26 having mounting pins 28 extending from either side thereof. Rotatably mounted on each pin 28 is a lug 30 fixed to a double acting cylinder 32. A piston rod 34 extends from one end of each cylinder 32 and has connected to its free end a bifurcated member 36 which pivotally retains a link 38. To facilitate the movement of the arms 22 responsive to the movement of the piston rods 34, the links 38 are pivotally attached to lug portions 40 of the arms 22. Attached to each bifurcated member 36 is a block member 42. A planar member 44 is fixed to each block member 42 and has a bore 46 therethrough (FIG. Fixed to the free end of each planar member 44 is a counterweight member 48. The bores 46 each receive a rod 50 which is mounted on a lug 52 connected to each of the cylinders 32. The rod 50 and the piston rods 34 are substantially parallel. Movement of the piston rods 34 into the cylinders 32 cause the planar members 44 to move axially of the rods 50. Such movement of the piston rods 34 also causes movement of the links 38 which cause the arms 22 to move from positions shown in FIG. 1 to positions shown in FIG. 2. As is described in more detail below, a treadle 54 (FIG. 1) may be used to actuate the cylinders 32 whereby to cause movement of the arms 22 in directions away from the footform 8. To the ends of the lasting string, each arm 22 has a clamp block member 56 which is pivotally connected to the arm 22 by link members 58. Also pivotally mounted on the block 56 is one end of an adjustable arm 60 which, at its other end, is pivotally connected to one end of the link 38. A coil spring 62 (see FIG. 4) urges each arm 60 upwardly whereby to cause the block 56 to be pivoted to a position in engagement with the arm 22. A lasting string S is gripped between the arm 22 and the spring-biased clamp block 56. A spring clip 64 may also be utilized as a string retaining means. The link 38 is pivotally connected to the lug portion 40 of the arm 22, as by a pivot pin 66. Acordingly, when the link 38 is moved in a counterclockwise direction, as viewed in FIG. 4, by the operation of the cylinder 32, the link 38 operates to move the arm 22 away from the footform 8 and also causes the arm 60 to exert pressure on the block 56 whereby to firmly grip the string S between the block 56 and the arm 22. Referring to FIG. 6, it will be seen that the treadle 54 operates a valve 70 located in a main air line 72. Depressing the treadle 54 shifts the switch 70 against spring pressure to permit air from the line 72 to enter air lines 74, 76. The line 74 connects with the rod end of each cylinder 32 thereby to urge the piston rods 34 downwardly. Air in the line 74 also enters an air line 78 to operate a valve 80 against spring pressure to exhaust the head ends of the cylinders 32 through an air line 82. For the sake of simplicity various reducing valves, air pressure gauges, and the like have been omitted from the pneumatic circuit diagrams. Referring still to FIG. 6, upon disengagement of the treadle 54 by the operator, the valve 70 is moved to the position shown in FIG. 6 whereby to interrupt flow of air to the rod ends of cylinders 32 and to exhaust the air lines 74 and 78. The switch 80 is moved by spring pressure to the position shown in FIG. 6 whereby to permit the passage of air from the air line 76 to the air line 82 and thence to the head ends of the cylinders 32 to cause the rods 34 to be moved upwardly. Referring to FIG. 7, it will be seen that the device may be provided with an alternative pneumatic circuit which permits independent use of the arms 22. In this embodiment the treadle 54 abuts a pivot bar 84 which is movable with the treadle, but which is biased against the treadle so as to resist movement with sufi'icient force to permit tilting of the treadle if desired. Located under the treadle are two valves 90, 92 which are connected to the main air line 72. The valve 90 is connected to an air line 94 which transmits pressurized air to an air line 96 which connects with the rod end of one cylinder 32. The air line 96 also connects with a shuttle valve 98 which operates to move a valve 100 against spring pressure to the position shown in FIG. 7, thereby allowing evacuation of the head end of the cylinders 32 through an air line 102. The valve 92 is connected to an air line 104 which is connected to the rod end of the second cylinder 32. If pressure is applied in the center of the treadle 54, the valves and 92 are operated simultaneously causing both piston rods 34 to be lowered. However, if it is desired to lower one rod, and thereby move just one arm 22, while leaving the other arm 22 in its upper position, the operator may apply pressure on one end, for example in the vicinity marked 106 in FIG. 7, of the treadle 54. If the treadle S4 is depressed by application of pressure in the area 107 the switch 90 will be moved to the position shown in FIG. 7 while the switch 92 will be Permitted to remain in its spring biased position. Accordingly, air will be permitted from the main air line 72, through the air lines 94 and 96, to the rod end of the cylinder 32 on the left side as viewed in FIG. 7. Inasmuch as valve 92 remains closed, air does not reach the rod end of the cylinder 32, on the right as viewed in FIG. 7. In FIGS. 6 and 7 the valves 70, 90 and 92 are of the type wherein the greater the depression of the foot pedal, the greater is the volume of air permitted to flow therethrough, and the greater the pressure applied to the rod ends of the cylinders 32. Accordingly, by proper manipulation of the foot treadle 54 the operator is able to apply pressure on both arms 22, but greater on one than the other if so desired. In operation, an upper to be string lasted is placed on the footform 8 in the position shown in FIG. 1. The lasting string S, which has been previously sewn to the upper, is manually inserted in the spring clips '64 for temporary retention and pulled down between the arms 22 and their respective clamping blocks 56. The springs 62 cause the adjustable arms 60 to continually exert clamping pressure on the blocks 56. Assuming for illustrative purposes that the pneumatic circuit shown in FIG. 6 is in use, the operator commences the string lasting operation by applying pressure to the treadle 54 to open the valve 70 and permit air from the main air line 72 to enter the rod ends of the cylinders 32 thereby drawing the rods 34 into the cylinders 32. Such movement of the rods 34 causes pivoting of the link members 38 about the pivot pins 66 whereby to apply greater pressure against the clamping blocks 56 to securely retain the ends of the string S between the clamping blocks 56 and their respective arms 22. Further movement of the piston rods 34 causes movement of the arms 22 downwardly and away from the footfor-m 8 to draw the string S taut, as shown in FIG. 2. The further the operator depresses the treadle 54 the more pressure does he cause to be applied on the arms 22. Release of the treadle 54 by the operator permits the arms to return to their upright position. It is evident from the above description that when pressure is applied to the rod ends of the cylinders 32, the head ends of those cylinders are exhausted and offer little or no resistance to movement of the respective pistons in the cylinders 32. Accordingly, in the event of the string S parting during the lasting operation the arms 22 would have a tendency to snap back toward the operator and thereby present a severe safety hazard. However, if there is an unexpected rupture of the string S and the piston rods 34 tend to move quickly into the cylinders 32, the counterweights 48 provide an inertial force which causes the planar members 44 to lag behind the movement of the rods 34. Such lagging movement causes the planar members 44 to cam against the rods 50 thereby stopping movement of the piston rods 34. By releasing the foot treadle 54 the operator permits the rods 34 to move outwardly from their respective cylinders 32 to release the binding engagement between the rods 50 and the planar members 44. Having thus described my invention, what I claim as new and desire to secure by Letters Patent of the United States is: 1. Apparatus for use in conjunction with footwear upper mounting means for providing power assistance in string lasting a footwear upper disposed on said mounting means, said apparatus comprising fluid power means engageable with a lasting string connected to said upper for drawing the string taut, and operator controlled switch means for operating said power means. 2. Apparatus for use in conjunction with footwear upper mounting means for providing power assistance in string lasting a footwear upper disposed on said mounting means, said apparatus comprising mechanical arm means, string retaining means on the arm means for retaining a lasting string connected to said upper, fluid power means for moving the arm means to draw the string taut, and operator controlled switch means for operating said power means. 3. Apparatus for use in conjunction with footwear upper mounting means for providing power assistance in string lasting a footwear upper disposed on said mounting means, said apparatus comprising first and second mechanical arms, string retaining means on said first and second arms for retaining opposite ends of a lasting string 6. The invention according to claim 3 in which said switch means is operable to cause said first and second arms to move and remain stationary independently of one another. 7. The invention according to claim 3 in which said switch means is operable to cause said first and second arms to draw said string taut under a selected and variable pressure. 8. The invention according to claim 3 in which said first and second arm moving power means operate responsive to said switch to move said arms independently of each other through distances and under pressures which are variable and selectable by an operator. 9. Apparatus for use in conjunction with footwear upper mounting means for providing power assistance in string lasting a footwear upper disposed on said mounting means, said apparatus comprising first and second mechanical arms, string retaining means on said first and second arms for retaining opposite ends of a lasting string connected to said upper, fluid operated cylinder means for moving said first and second arms to draw the string taut, said arms being movable to exert a variable and selected pulling force on said string, operator controlled switch means for energizing said cylinder means, and means for terminating the movement of said arms upon parting of said string. References Cited UNITED STATES PATENTS 1,833,229 11/1931 Sahr 127.9 X 2,125,884 8/1938 Brothers 127.9 2,344,503 3/1944 Cuozzo 12145 PATRICK D. LAWSON, Primary Examiner

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Patent Citations (3)

    Publication numberPublication dateAssigneeTitle
    US-1833229-ANovember 24, 1931Sahr FrankMachine for lasting shoes
    US-2125884-AAugust 09, 1938United Shoe Machinery CorpMachine for lasting shoes
    US-2344503-AMarch 21, 1944Cuozzo MicheleLasting shoes

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    US-4118815-AOctober 10, 1978Renato CrimellaAutomatic toe forming machine for shoes, in particular dancing and gymnastics shoes
    WO-2016197213-A1December 15, 2016I.S.A. Indústria de Tecnologia e Automação LTDA - EPPMáquina para montagem de cabedal com tracionador de cordões