GB1468427A - Strap tensioning tools - Google Patents

Abstract

1468427 Strap tensioners SIGNODE CORP 18 June 1974 [18 June 1973] 26966/74 Heading F2G A strap tensioning tool comprises a main frame 12 having a nose 14, an anvil portion 15 to the rear of the nose, a gripping assembly 18 immediately above the anvil 15 being pivoted to the main frame 12 and carrying a tension handle 20, extending above the main frame, employed both to tension the strap and to transport the gripping assembly 18 from a strap loading to a strap gripping and feeding position. The strap feeding assembly and the bifurcated pivot end of the tension handle 20 are pivotally secured to the frame 12 through a shaft 44 on which is also mounted a ratchet gear 46 driven by engagement with a drive pawl 48 pivotally mounted on the tension handle 20 between the bifurcations thereof and being biased by a spring in a clockwise direction as viewed in the figure. A second shaft 52 is also provided within the strap feeding assembly 18, being parallel to the shaft 44 and passing through the main frame 12, and having mounted thereon a tension gear 54, engaging with the ratchet gear 46, and a knurled strap feed wheel 56 which co-operates with a wear plug 36 associated with the anvil 15 to grip and feed a strap inserted therebetween. The shaft 44 is biased by a spring 42 acting against the main frame 12 such that the spring resists the raising of the strap feeding assembly 18 relative to the frame 12 through a lift arm 60, pivotally secured to the frame 12 by a pin 61, comprising two arms 62 and 64, the latter of which engages an extending projection of the strap feeding assembly 18 and the former engaging the underside of tension handle 20. In order to prevent reversal of the rotation of the wheels 56 and 54 when the tension handle 20 is released holding pawls 72 and 74 are carried within the drive section 38 of the strap feeding assembly 18 to engage the gear 54 being biased by a coil spring and being placed such that only one holding pawl is in engagement at any one time. The force required at the surface 66 transmitted through the lever 60 from the tension handle 20 to lift the strap feeding assembly 18 relative to the anvil is required to overcome the moment of the strap tension about the shaft 44 and thus, due to the disparity in moment arms between on the one hand the force exerted by tension handle 20 on the lever arm 62 about pivot 61 and on the other hand the strap tension about shaft 44, the operator should therefore find it difficult to accidentally raise the strap feeding assembly 18 releasing the strap by overshooting the tension stroke and contacting the lever arm 62 with the tension handle 20 while the strap is in tension.