Patent GB-1136847-A (GB)
Title: Improvements in apparatus for strapping
IPC: B65B13/32
Filed: 1967-02-01
Abstract: 1,136,847. Seaming non-metallic sheet material. SIGNODE CORP. 1 Feb., 1967 [2 Feb., 1966 (2)], No. 4819/67. Heading B5K. [Also in Division F2] Apparatus for strapping an article A with a closed loop of thermoplastic strap, e.g. nylon or polypropylene, comprises means to tension the loop about the article A and sealing means comprising confronting pressure jaws 171, 172 to compress overlapping portions U, L of the strap together and means operable during compression by the jaws to shift the portion U through a one-way travel stroke relative to the portion L to frictionally weld the contacting surfaces of the portions U, L. The embodiments described with reference to Figs. 4-9 (all not shown) are identical with those shown in Figs. 12-17 of Specification 1,136,846. In a further embodiment of a manual tool, Figs. 11, 12 and 14, the tensioning means comprises a ratchet and feed wheel unit 157 journalled on a shaft 158 which rides in a carrier 154 normally urged in a counter-clockwise direction by a spring 156. Upon reciprocation of a handle 167, supporting a shaft 168, between the positions of Figs. 11 and 13 (the latter not shown), a tensioning pawl 161 carried by a sealer frame 162 and a holding pawl 164 mounted on the carrier 154 repeatedly engage, advance and hold the feed wheel. When the desired tension is achieved the handle 167 is moved to the position of Fig. 13 (not shown), to seat the frame 162 upon the strap portions U, L which overlie the stationary sealer jaw 172. At this point, the rotary position of the shaft 168 is such that supports 177, 178, Fig. 12, hold the movable sealer jaw 171 at a minimum pressure relation with respect to the strap. Initial swinging movement of the handle 167 with respect to the frame 162 releases cam rollers 189 and enables springs 188T to swing reaction jaws 188 beneath the jaw 172 to take the reaction that develops as the jaw 171 is impressed upon the strap. Further rotation of the handle 167 towards the position of Fig. 14 rotates the shaft 168 to lower the supports 177, 178 and pressure load the jaw 171 on to the strap. The swinging movement of the handle 167 also causes a pawl 169 to rotate a bell-crank 176 counterclockwise of Fig. 14 to lift a connector rod 183 so that a seat 186 compresses a high strength main spring 187 in a housing 166. Simultaneously, a link 184 carried by the bell-crank 176 retracts the jaw 171 so that the strap portion U is drawn slack. Retraction of the jaw 171 kicks an extension 161E of the pawl 161 to disengage this pawl, with the spring 163 holding the same disengaged, to enable return of the handle 167, after joint formation, without producing straptensioning movement of the feed wheel. The spring 187 is fully compressed and the jaw 171 is fully retracted when the handle 167 reaches the position of Fig. 14. Upon further rotation of the handle 167 the pawl 169 rides on to an abutment in the form of corner trips 177T on the supports 177, 178 and lifts off the bell-crank shoulder 176S to free the bell-crank. Immediately, the spring 187 drives the bellcrank 176 clockwise and a corner thereof kicks the pawl 169 free to enable continued movement of the handle 167. This rapid movement powers the jaw 171 through a rapid one-way travel stroke sufficient to achieve interface melting between the contacting strap surfaces. The jaws 171, 172 continue to act on the stationary portions U, L until solidification is effected. A cutter 170 is now exposed and further movement of the handle 167 causes an extension 169E to drive a cutting edge 170E through the portion U immediately adjacent the joint. The cutting stroke is limited by contact of a gauge face 170F with the upper strap. The handle 167 is returned to the position of Fig. 11 to release the sealed strap loop.