GB478220A - Improvements in safety catches for hoist conveyances - Google Patents

Abstract

478,220. Safety-catch-gear for lifts &c. JAECKEL, F. O. Aug. 10, 1936, No. 22009. [Classes 78 (iii) and 78 (v)] Safety-suspending and rope-releasing apparatus for mine cages and skips, which is brought into action on an overwind, on overspeed, at the bottom limit of the run, and when the suspension rope breaks, is capable of being actuated solely by excess tension in the winding rope at any point in the travel of the cage or skip, such actuation operating both the brakeapplying gear and the rope-releasing means. In the form shown the invention is applied to a skip 3 provided with a supporting framework to which the mechanism is fitted. Brake shoes 36 on the skip frame are applied to the opposite sides of the guides by a plurality of hydraulic rams 33 connected to four main ram cylinders 44, the rams 43 of which are provided with lateral projections or pivots 48 engaging hooks 47 on a T-piece 50, each pair of rams thus holding springs 41 in compression. The T-piece is supported and steadied by light springs 53. If the winding-rope breaks when the apparatus is running under normal conditions, the king-bolt 9 drops, and allows the compression spring 15 to force the member 10 downwards, thus causing the attached feet 55 to move the T-piece 50 downwards bodily and detach the hooks 47 from the rams 33. The springs 41 then force those rams into the cylinders 44 and transmit pressure to the brake rams 33. In the event of overstrain on the winding-rope, sufficient pressure is transmitted through the pivoted levers 18 to compress the springs 25 until collars on rods 27b are contacted by the levers. Further movement then shears the pins 29 and allows the rods to move downwards to rock the T-piece 50 about one or other of the pivots 48, thus releasing the rams 43 in succession. Similarly on an overwind, the tops of the rods 27b strike an abutment and shear the pins 29. The T-piece 50 may also be rocked by the engagement of a projection 58 with a fixed member 59 at the bottom of the shaft to prevent over-lowering, or with a member 60 projected by a governor into the shaft on overspeed. A hand pump 64 is operated to re-set the rams after they have been operated. Disengaging the winding-rope. When the winding-rope is subjected to excessive strain without actually breaking, or when the broken end arrests the falling cage suddenly by catching in an obstruction, the levers 18 shear the pins 29 as previously described. This permits sufficient additional compression of springs 25 to enable the levers to rotate sufficiently to disengage their hooked ends from the collar 13, thus releasing the whole king-bolt-assembly from the skip or cage. The guide tube 16 on the cage is split to enable the lugs 31 on the member 10 to pass during this detaching movement. A handrope 61 can also be fitted to apply the brakes in an emergency when the skip is used for hoisting men.