GB621529A - Drop hammer - Google Patents

Abstract

621,529. Power hammers. CHAMBERS-BURG ENGINEERING CO. Jan. 7, 1947. No. 526. Convention date, Oct. 8, 1946. [Class 83 (iv)] A drop hammer of the kind operated by air or other elastic fluid under pressure, comprises a ram adapted to drop freely by gravity, a pressure fluid actuated piston to raise the ram, clamping means which automatically hold the ram in its raised position, and means to render the clamp ineffective. The hammer comprises side frames 2 between which slides the tup 7, connected by a rod 6 to a piston 5 movable within a cylinder 4. The bottom of the cylinder may be connected to a source of pressure fluid or to exhaust by means of a valve 36, the sliding element 38 of which is operable by a vertical rod 58 acting through a bellcrank lever 61. Disposed on opposite sides of the rod 6 are two blocks 10, 11 lined with friction material 12 and pivoted between two parallel plates 14 which are in turn pivoted at one end 17 to the machine frame and at the other end 21 to a link 22. A rocking lever 23 pivoted to the machine frame at 25 is connected to the link 22 at one end and to the rod 30 of a fluidpressure actuated piston 29 at the other. A spring 27 biasses the rocker so that the ends 21 of the plates 14 are normally depressed to move the blocks 10 and 11 into gripping engagement with the rod 6. The clamp may, however, be released to allow the tup to drop by actuating a treadle 34 to permit pressure fluid to flow into the cylinder 28 and depress the piston 29. As the tup approaches the anvil 8, it engages a dog 48 at the lower end of a pivoted lever 45 which, through levers 53, 54 moves the rod 58 controlling the valve 36 so that pressure fluid is admitted beneath the piston 5. As the tup rises again an upper bevel 51 thereon engages another dog 49 on the lever 45 to cut off the supply of pressure fluid and the tup continues its upward movement by momentum and by the expansion of the fluid already supplied. When the bevel 51 reaches an upper dog 50, the cylinder 4 is connected to exhaust and the tup either falls again or is held up by the clamping blocks 10, 11 according to the position of the treadle 34. An upward movement of the rod 6 acts to release the brake.