Patent GB-952706-A (GB)
Title: Strapping tool
Inventor: HALL MARCHAND BLANCHARD
IPC: B65B13/34
Filed: 1962-04-26
Abstract: 952,706. Sealing. ACME STEEL CO. April 26, 1962, No. 15942/62. Heading B6P. [Also in Division F2] A strapping tool for tensioning and sealing the overlapping ends 11, 12 of a loop of strap 13 encircled about an object 168 comprises a frame 1 having a strap rest portion 170 over which the strap is passed, a pair of strap grippers 5, 6 means for moving the strap grippers to and from strap gripping position, a sealer head 8 mounted on the frame for movement to and from sealing position, and means connected between one of the strap grippers and the sealer head to move the latter in response to the movements to and from strap gripping position of said one strap gripper. As shown the strap tensioning wheel 5 is carried on an auxiliary frame 4 which is pivoted at 3 to the main frame and is urged in a clockwise direction as seen in Fig. 5 by a spring 15, Fig. 8, surrounding the pin 3. The movement of the frame 4 is controlled by a shaped arm 40 pivoted at 41 and urged by a helical spring 42 in a counter clockwise direction as seen in Fig. 5. The arm 40 carries a pin 35 which co-operates with a cam plate 32 fixed to a lug 30 of the main frame. The other gripper is in the form of a springy flat blade 6, Fig. 8, one end of which is mounted by two bolts 49 and the other 48 overlies the strap. An arm 46 pivoted at 47 to the auxiliary frame 4 passes through a slot 51 in the gripper 6 so that its lower end 52 which is provided with two laterally extending fingers 53, 54 normally prevents the gripper 6, urged by its own springyness, from lying flat. The movement of the sealer head 8 which is pivoted at 57, Fig. 12, on the frame 1 and urged to its sealing position by a spring 58 is controlled by the auxiliary frame 4 by means of a pin 60 on the rear of the sealer head extending through an opening 61 at one end of a link 63. The latter is provided with an elongated opening 64 through which passes a pin 65 attached to the frame 4. The movement of the pin 60 is controlled by cam surfaces 67, 68 which prevents the sealer head from moving to sealing position before strap ends 11, 12 have been positioned beneath the head. Tensioning.-The strap end 11 is positioned beneath the sealer head and is extended back over the gripper plug 7 fastened in the strap rest portion 170. At this point the arm 40 is depressed so that the pin 35 normally held in the recess 36 moves to the recess 37 in the cam plate 32 and permits the auxiliary frame 4 to lower the strap gripper 6 to hold the strap end 11. The strap is then looped about the object 168 and the strap end 12 passes beneath the sealer head and across the rest portion 170. The lever 40 is raised in order to cause the auxiliary frame 4 to move further downwardly so that the pin 35 moves to the recess 38 and the tensioning wheel 5 grips the strap end 12. The strap is tensioned by rotating the wheel 5 by an air motor 28, Fig. 15. The wheel 5 is mounted on a shaft 18 provided with a gear 20 which meshes with a gear 21 mounted on a shaft 22 in turn provided with a bevel gear 24 engaging a bevel gear pinion 25 mounted on a shaft 26 of the motor 28. Air from a pressure line is admitted to the motor 28 by a valve lever 28a to rotate the wheel 5. Also mounted on the shaft 22 is a toothed ratchet wheel 199 engaged by a pawl 204 which is pivoted on a pin 200 with a spring loaded lever 201 adapted to disengage the pawl after the strap has been tensioned and sealed. Sealing.-The sealer head 8 is moved by the auxiliary frame 4 during its strap gripping movements to the sealing position and a new seal is positioned over the strap ends. The sealer head 8, Fig. 12, comprises two chambers 89, 90 separated by a diaphragm 91. Air is admitted into chamber 89 from the air line by a valve 162 actuated by a plunger 163. A plunger 94 is urged by the springs 96, 97 against the diaphragm and has a toothed rack 86 rigid therewith which engages a toothed sector 83. The sector 83 is connected by two links 80 to a pin 77, Fig. 13, which is supported on two slide bars 74, 76. The latter also carry a pin 78 journalled in the ends of two links 103, 104. The link 103 is of single thickness and is provided with two rollers 105 at its lower end 106. The link 104 is forked at its upper end and is provided with two rollers 109 at its lower end. These four rollers 105, 109 bear against the upper surface of two vertical punches 112 to cause their downward movement. The punches 112 are provided with two cam surfaces 113 which react against the metal seal and have two slotted openings 114 which are guided on pins 115, 116 held rigidly in place by nuts 117. The pins 115, 116 act as pivots for the two middle jaws 118, 119 and the four outer jaws 120, 121, the latter also being pivoted on the pins 107, 110 carrying the rollers 105, 109. The jaws are connected by pins 122, 123. With this linkage arrangement when the rack 86 is extended by the admission of air pressure into chamber 89 the slide bars 75, 76 move downwardly to in turn move the punches 112 downwardly and cause the jaws 118, 119, 120, 121 to pivot. The tips 127 of the jaws push the seal legs 10a beneath the overlapping strap ends to serve as a reaction force to the downward force exerted by the sloping portions 113. This action causes the tabs 14 to be severed and bent downwardly to form the seal shown in Fig. 9. The vertical movement of the slide bars 74, 76 also feeds a seal from a seal stack housing 100 in which the seals are stack one on top of another with their legs 10a extending downwardly. The seals are urged downwardly by a spring 133 connected between the lower end of the housing 100 and a plunger 132. As the slide bar 74 slides vertically downwards an L-shaped arm 144, Fig. 5, connected to the slide bar reacts against an adjustable screw 143 to lower the end 142 of a bell crank arm 139. The arm 139 rotates to cause the seal feed arm 136 to move away from the sealer jaws to a point where its end passes completely beneath the seal stack to where it engages the edge of the lowermost seal. When the slide bar 74 is raised vertically, the arm 136 moves the lowermost seal into position between the sealer jaws. Cutting.-When the seal is almost completely formed by the punches and sealer jaws the final downward movement of the slides 74, 76 causes the pin 78 to contact the outer end 150 of a lever 151, Fig. 14. The arm 157 pivots downwardly on a pin 153 to contact the upper surface 154 of a shear blade 155, pivoted on a pin 156, which shears the strap end 12 from the supply reel. To prevent the sealer head from being raised if the jaws are partially or completely closed an upstanding ear 173 having a pin 174 is provided on the frame 1. The pin 174 is in the path of a semi-annular projection 175 which is connected to the outer end of a pin 153. If the jaws are still closed when the sealer head pivots upwardly the pin 174 strikes the surface 176 and causes the pin 153 to rotate which raises the slide bar 74 to retract the jaws by means of the arm 151. In a modification an extension of the pin 110 contacts a cam on a lug fastened to the frame 1 to prevent the sealer head from being pivoted back before the jaws are retracted.