GB268443A - Loading and unloading devices for vehicles - Google Patents

Abstract

268,443. Ducondu, P. Jan. 2, 1926. Pulley-tackle platform load-handling machines. -A loading platform 21 is carried by arms 17 pivoted on a shaft 14 which is carried by arms 15 pivoted to the vehicle chassis at 16. The platform is raised and lowered between the positions shown in Fig. 3 and in Fig. 1 by chains 37 engaging chainwheels 36 driven by ratchet gearing. The platform is supported by chains 26 from uprights 22 pivoted on the shaft 14 and stayed by chains 27. The ratchet drive comprises a handle 45, Fig. 7, pivoted on the shaft 35 which carries a ratchet wheel 41 and the chain-wheel. A holding-pawl 53 pivoted at 34<a> is normally engaged with the ratchet wheel by gravity. A hoisting-pawl 43<a> is pivoted on the handle at 43 and is normally held in engagement with the ratchet wheel by a spring 48. A second spring 51 secured to the tail of the hoisting pawl is attached to a lever 52 which is placed in the full-line position for hoisting and in the dotted-line position for lowering. In the latter position, the spring 51 opposes the spring 48 and a spring 57 is brought into position to engage the pawl 53 when the handle is depressed. When the tension in the spring 48 is relaxed by raising the handle, the spring 51 disengages the pawl 43a whilst the ratchet wheel is held by the pawl 53. When the handle is again lowered, the. spring 48 overcomes the spring 51 and the load is supported by the hoisting pawl whilst the pawl 53 is disengaged by the spring 57, thus allowing the ratchet wheel to turn by one tooth at each upstroke of the handle.