| 摘要 |
379,190. Jib cranes. FAURE, A., Rue Verdier, and FAURE, A., 8, Rue de la Loire, both in Firminy, Loire, France. Dec. 30, 1931, No. 36023. Convention date, Feb. 21. [Classes 78 (iv) and 78 (v).] A jib crane comprises a detachable rigid member, carrying a pulley at its outer end, which can be pivoted to the lower end of an upright for use as a luffing jib and be connected to the upper end of the upright for use as a tie bar in combination with another member, secured to the lower end of the upright, to form a rigid jib. As shown in Fig. 1, the member 13, acting as a luffing jib, is provided with a pulley 16 and is pivoted at 14 on a bracket 15 rigid with an upright 9 which is pivotally mounted on a post 1 by collars 10, 11. When the rope 22 is drawn in a plate 26 thereon engages a channel member 21 and raises the jib 13 which on approaching its highest position engages by means of a pin 38, a lever 34, pivoted at 35, and depresses a collar 33 so as to actuate a lever 28 and declutch the hoisting gear 4. Projections 27, Fig. 6, on the member 21 engage links 23 on the rope 22, when the jib is in its highest position, to prevent the rope slipping. In a modification, Fig. 8, the member 21 is provided with a recess 25<1> to receive a block 25 on the rope 22. The block may be spherical, the recess 25<1> being correspondingly shaped. In a further modification the cross-section of the member 21 is shaped so as to grip the rope frictionally A chain 18, Fig. 1, provided with a spring 19 limits the descent of the jib. As shown in Fig. 3, the member 13 acts as a tie bar to support a jib 13<1>. When the load hook 24 approaches its highest position the plate 26 engages an arm 40, pivoted at 41, and through the chain 18 and spring 19 actuates the lever 34 to declutch the hoisting gear as described above. In a modification in which the crane is mounted on a sloping roof the rope 22 is guided by pulleys 12, 17, along the axis of the post 1 to the hoisting gear below, stability being maintained by a counterweight. A device, Fig. 10, for fastening the tie-bars 5, 5<1>, to the frame 2 or collar 6 comprises a slotted stud 44 attached to the frame or collar and carrying a pivoted slotted plate 47, which is aligned with the stud to permit the tie bar being placed thereon and is then turned to the position shown. |
