Patent GB-697454-A (GB)
Title: Overhead travelling hoists for handling loads
IPC: B66C3/08
Filed: 1950-01-17
Abstract: 697,454. Overhead-travelling hoisting-apparatus; drop-bottom skips. SOC. FRANCAISE DE CONSTRUCTION DE BENNES AUTOMATIQUES. Jan. 17, 1950. [Jan. 19, 1949] No. 1239/50. Class 78 (iv). Overhead - travelling hoisting-apparatus. The apparatus illustrated in Fig. 1 automatically performs a sequence of operations during which a loaded skip 10 is raised by a cable 12 to engage a crown 9 by which it is supported from a carriage 3, the carriage is allowed to run down inclined rails 2 until it meets a stop 5, dropbottom doors in the skip 10 are opened to discharge its contents into a cupola 15 and are then closed again, the carriage is drawn back up the rails, and the bucket is lowered to receive a fresh load. The carriage 3, is supported by rollers 4 engaging the lower flanges of a pair of inwardly facing channel rails 2. A beam 8 pivoted at 7 to the carriage supports the crown 9 through a spring 50, Fig. 7, and also carries a pulley 11 over which the cable 12, which is driven from a winch 13 and motor 13a, Fig. 1, passes from a fixed pulley 14. While the skip 10 is being loaded the carriage 3 is held from running down the rails 2 by a latch 21 which engages a fixed stop 24. When the motor 13a is started and raises the skip to abut against the crown 9, the carriage 3 is drawn up the rails 2 to abut against a stop 6 and the beam 8 is then turned in the direction of the arrow f, about its pivot 7 and operates a switch 17 which reverses the motor 13a so that the skip is lowered to rest on pawls disposed within the crown 9. The weight of the skip then turns the beam 8 in the opposite direction so that it engages a spring- biased abutment 19 and causes it to release the latch 21 so that the carriage may run down the rails 2 until it engages the stop 5. The slackening of the cable 12 when the carriage engages the stop 5 causes the drop-bottom doors of the skip 10 to open as described below, and also causes a switch 68 operated by a lever 64 carrying a roller 66 urged against the cable by a counterweight, to reverse the motor 13a so that the doors of the skip are closed again and the carriage is drawn back up the rails 2. When the carriage again reaches the stop 6 the cable 12 raises the bucket from the crown 9 and causes it to turn the beam 8 about its pivot 7 to operate the switch 17 and again reverse the motor 13a. The removal of the weight of the bucket from the crown 9 allows the crown to be raised by its spring 50, Fig. 7, so that a weight 59 guided by a slot 60, Fig. 7, engaging a pin 61 on the rails 2, engages a pin 58 on a lever 54 carried by the crown to release the pawls for supporting the skip as described below. The skip 10 is thus lowered from the crown until it reaches the ground when the carriage 3 runs back clear of the weight 59 until the latch 21 engages the stop 24, and the cable then slackens to permit the switch 68 to stop the motor 13a. When the skip is subsequently raised again and the carriage drawn up to the stop 6 the pin 58 engages the side of the weight 59 and swings it about the pin 61 so that the pawls in the crown 9 for supporting the skip are not withdrawn. Single-rope grabs and drop-bottom skips, crowns for suspending and opening. As the skip 10 is raised its head 27, Fig. 7, is guided through a tube 51 and a flange 28 on the head pushes aside pawls 52 which then fall back into position to engage the flange and thus support the skip. When the crown 9 is raised by its spring 50 as described above so that the pin 58 on the lever 54 engages the suspended weight 59, the lever 54 is turned from its normal position in which it engages a stop 62, into a position, defined by a stop 63, in which a projection 56 on the lever engages pawls 57 carried, outside the tube 51, on the same shaft as the pawls 52 which are thus retracted to release the head 27 of the skip. Skips with drop-bottom doors. The doors 25, Fig. 3, of the skip are connected at each side of the body by links 34 to a crosshead 33 on a tube 32 sliding in a tube 37 fixed to each side of the body of the skip. The doors are locked in their closed position by engagement of rollers 41, Figs. 4 and 5, carried on levers 39 pivoted at 38 to brackets on the skip body, with recesses 48 in the tubes 32 : the levers 39 are held in this locking position when rollers 40 at their upper ends are prevented from passing through holes 47 in the tubes 37 by an abutment 43 on a tube 42 sliding within each tube 37 and urged upwardly by a spring 44 to abut at 46 against a closure 36 for the tube 37. The skip is suspended from the cable 12 by a beam 26, Fig. 3, secured at each end to a rod 30 which passes through the tubes 32, 42, 37 and terminates in a head 31 which normally abuts against the bottom of the tube 32. When the skip is suspended by its head 27, which is secured to the body, from the crown 9, and the cable 12 is slackened, the beam 26 descends to engage the tubes 42 and, by its weight, depress them against the action of the spring 44. The rollers 40, Figs. 4 and 5, may thus enter the holes 47 in the tubes 37 so that the tube 32 is no longer locked by the rollers 41 and the doors 25 may fall open. When the cable 12 is again drawn in the rod 30 is raised so that its head 31 engages the tube 32 and raises it, closing the doors 25 and permitting the rollers 41 again to latch the tube 32 in its raised position. Specification 524,514 is referred to.