Patent GB-750807-A (GB)
Title: Improvements in or relating to machines for attaching heels to shoes
IPC: A43D79/00
Filed: 1953-07-23
Abstract: 750,807. Heel-attaching machines. BRITISH UNITED SHOE MACHINERY CO., Ltd., GARRATT, L., and RIVINGTON, A. A. July 22, 1954 [July 23, 1953], No. 20433/53. Class 17 (1). In a heel-attaching machine generally similar to that described in Specification 580,814, wherein a heel and a lasted shoe are clamped, fasteners are driven part way into one of the clamped parts, and the heel thereafter attached to the shoe by pressing the shoe and heel together, the clamping means are caused to apply light initial clamping pressure to the work by hydraulic means instead of by the effort of the operator. The clamping means are operated by movement of link 10, Fig. 2, connected to the rod 12 of piston 14 which is spring-urged downwardly. Pump 24, fitted with an adjustable relief valve, pumps oil through pipe 44 to recess 46 located between sleeve 26 and the valve body 18 in which the sleeve is slidable. When spool 30 is raised relative to sleeve 26 oil escapes from recess 46 through ports 54 to a chamber 56 surrounding the shank 58 of the spool, and through holes 60, 62 in the shank and pipe 63 to the sump 42. When the spool is lowered sufficiently relative to sleeve 26, by depression of the spring-raised treadle 96, Fig. 4, piston 72 covers ports 54 and oil can escape from recess 46 only via passage 64, raises piston 14. As soon as piston 14 rises, pinion 32 meshing with racks on the piston rod and sleeve 26 acts to lower sleeve 26 and open ports 54 to bring the piston to rest. Thus to raise piston 14 steadily to operate the last-engaging abutment of the shoe-engaging means, spool 30 must be moved steadily downwards. Conversely, if spool 30 is moved upwardly the piston will be spring urged downwardly and sleeve 26 will move upwardly. If downward movement of spool 30 is arrested while piston 14 is free to move, the piston is spring urged downwardly and sleeve 26 is moved by pinion 32 to close ports 54 and bring the last engaging abutment to rest. Downward movement of piston 14, and hence upward movement of sleeve 26, is limited by means not shown, and if no workpiece is present upward movement of piston 14 is limited by contact with the end of the piston chamber. Downward movement of spool 30 relative to sleeve 26 is limited by engagement of the adjustable nut 66 with cap 70 so as to just seal ports 54. Light pressure on the treadle rocks bracket 84 about pins 88, and through 82, 80, 76, 75 lowers the spool, link 100, connected to the treadle by projection 98, rocking about pin 104, but when piston 14 is brought to rest by engagement of the clamping means with the workpiece, and nut 66 is engaged with cap 70, increased pressure on the treadle rocks the treadle about bar 86, and through 98, 100, 106 trips the clutch to actuate the mechanical pressing means. When necessary, e.g. for adjusting the machine, the clutch may be tripped without causing movement of the shoe clamp by moving lever 108 so that stop screw 112 engages the base and prevents rocking of bracket 84 when the treadle is depressed. Weight 110 holds lever 108 in either the inoperative or operative position with stop pin 116 engaged by the corresponding abutment 118 or 114. Specification 23031/11, [Class 17], also is referred to.