GB1100514A - Strapping tool - Google Patents

Abstract

1,100,514. Strap tensioning tools. SIGNODE CORPORATION. 24 May, 1966 [24 May, 1965], No. 23142/66. Heading F2G. [Also in Division B6] A pneumatically-operable strapping tool for tensioning a loop of strapping about an article A, the loop having overlapping free end and feed end portions 42 threaded through a seal 46, and for thereafter crimping the seal about the overlapping portions, comprises a frame adapted to rest upon the article, a strap tensioning assem bly 14, a sealing assembly 16, and a strap shearing unit 48. The tensioning assembly 14 includes a pneumatic motor 30 connected through a gear reducer 32 to a strap tensioning wheel 34 between which and a co-operating back-up roller 36 the strap end 40 is fed. Upon first depression of a lever 24 a piston-cylinder unit 50 moves the assembly to a lowered position wherein its axis is coincident with the line y-y to engage the strap between the wheel and roller. When the strapping has attained the necessary tension the lever is again depressed and actuation of a piston-cylinder unit 52, Fig. 6, effects the seal crimping operation which is followed by actuation of the shearing unit 48 to sever the strapping S near the crimped seal. After the severing operation the tool is automatically operable to restore the assemblies 12, 14 and 16 to their original positions as shown in Fig. 1. The seal crimping unit comprises a piston-cylinder device 52 the plunger 162 of which is fixed to a crosshead 160 the cross-pin 158 of which is guided in a slot 156 in one plate 152 of a pair of plates. Pins 168 support a plate 166 between the plates 152 and pivoted on the pins are members 170 having seal-retaining and crimping jaws 172 and connected to spreader links 174 connected to the pin 158. The piston 164 is yieldingly biased downwardly by a spring 182 so that when the lower region of the cylinder 126 communicates with the atmosphere, the piston is forced downwardly by the spring to move the jaws 172 into holding engagement with the seal 46 under slight pressure insufficient to crimp the seal; air is subsequently supplied to the cylinder to augment the action of the spring and to force the piston to its fully advanced position whereby the seal is fully crimped. The shearing unit 48 includes a cutter 97 pressed by a spring 98 to a raised position and is adapted to be forced downwardly by engagement with the pin 158 on the crimping unit after the crimping operation has been completed. Operation of the tool is effected under the control of two valve assemblies (200), (202), Fig. 7 (not shown), and actuation of the valves is effected under the control of a compound lever and latch mechanism and the lever 24. A spring-pressed detent ball 93 co-operates with a pin 94 to grip the strapping as the latter emerges from the wheel 34 so that the feed end of the strapping is readily accessible for the next strapping opera tion.