Patent GB-814507-A (GB)
Title: Improvements in or relating to apparatus for making sliding clasp fasteners
IPC: A44B19/40
Filed: 1957-05-15
Abstract: 814,507. Sewing machines. CUE FASTENER Inc. (Cue Fastener Corporation). May 15, 1957, No. 15450/57. Class 112 [Also in Group XXV] Apparatus for making sliding clasp fasteners stringers comprising fastening elements connected to each other and sewn to a stringer tape comprises a sewing machine by which the fastening elements are sewn to the tape and both the fastening elements and tape are continuously fed forwards, means for maintaining the tension of the tape as it reaches the sewing machine substantially constant, means for feeding a continuous string of the fastening elements to the sewing machine at the same rate as the tape and the elemnts are fed forwards by the sewing machine, a clutch for interrupting the feed of the string to the sewing machine, a cutter for cutting the string at intervals in a position before the string is sewn to the tape and means for engaging and disengaging the clutch and operating the cutter in timed relation to the operation of the sewing machine so that string of fastening elements is cut into lengths which are sewn to the tape end to end with spaces between them. In the machine shown in Fig. 1 left and right hand stringers are made simultaneously, two sewing machines 10, 11, being used for stitching the strings of fastening elements to tapes 14, 15. A common means for tensioning the tapes is provided; this comprises two drums 16, 25, one for each tape which are fixed to a common shaft 17. The tapes pass under tensioning rods 19, 20, and over the drums 16, 25, and the tensioning force is applied by a brake comprising a drum 21 also fixed to the shaft 17 which is engaged by a brake band 22 held into contact with the drum 21 by a weight 23 or a spring. The tapes then pass direct to the sewing machines. Each fastening element is one convolution of a coil of wire or strip metal or of a resilient plastic such as nylon; as initially formed the elements of each string are intermeshed to form a single continuous length which can be separated into two strings by pulling. The length of intermeshed elements is supplied from a tote box 30 which comprises a conical centre portion 31 mounted on a cylindrical shell 32 which is co-axially mounted in spaced relationship to a cylindrical rim 33 the whole being mounted on a support 34. The intermeshed strings are fed out through an eye 35 on a spring arm 36 to a separator 47 which consists of a pair of diverging flexible tubes which separate the length of fastening elements into two strings 12, 13. The strings are fed to the sewing machines by a device 40; this has feed sprockets 59, 60, for moving each string, the sprockets being driven by a worm gear 57 which in turn is driven by a worm wheel 56. The worm wheel is driven through gearing by the motor which drives the sewing machines. The worm gear 57 and the worm wheel 56 together constitute the clutch by which the feed of the elements to the sewing machines may be interrupted since the worm wheel is freely rotatable on a shaft 51 which can be moved away from the worm gear 57 by means of a solenoid 70. The clutch is used in conjunction with the cut-off mechanism 75 for cutting the strings 12, 13, into the sections of fastening elements, each of a predetermined length, and, since the sewing machines operate continuously, when the cutter has operated, the sections are fed forwardly whereas the feed of the strings 12, 13, from the tote box is interrupted so that gaps are produced between the separate sections of fastening elements as is necessary for the separate fasteners. The cutter comprises a fixed shear blade 76 and a movable shear blade 77 which is operated by a solenoid 78. The solenoid 78 and the clutch solenoid 70 are operated sequentially since when a motor driven switch operates the clutch solenoid 70, to stop the feed of the coils 12, 13, an extension of the shaft 51 on which the worm 56 is mounted operates a switch which in turn operates the solenoid 78 to cause the shear blades to cut required length of fastening elements to form the sections. The two solenoids can however be operated simultaneously if desired. In a modification separate tensioning means are supplied for the two tapes 14, 15.