Patent GB-690112-A (GB)
Title: Draw bench mechanism
Inventor: LAKE NORMAN CECIL
IPC: B21C1/32
Filed: 1950-04-21
Abstract: 690,112. Draw-benches. HEAD WRIGHTSON MACHINE CO., Ltd. April 18, 1951 [April 21, 1950], No. 9912/50. Class 83 (iv). In a draw - bench having a travelling carriage for drawing the work and a back bench including at least two sets of guide members from which the work is alternately fed to the dies while the other set is being loaded, feed mechanisms are provided which grip and advance the work to a position adjacent the dies or for engagement by the push printing mechanism. A back bench B, Fig. 1, for a draw-bench comprises two sets F<SP>1</SP>, F<SP>2</SP> of three guide tubes 1, 2, 1, Fig. 2, which are slidably or rotatably mounted so as to be interchangeable between a charging position S<SP>1</SP> opposite a magazine M and a discharge position S<SP>2</SP> opposite the draw bench D. Tubes or rods stacked in the magazine M are fed to the guide tubes through conical guides 53 by pinch rolls &c. (not shown), at the position S<SP>1</SP> and are fed up to the dies or push pointing mechanism (not shown), at the position S<SP>2</SP>. The feed mechanism comprises a set of three pneumatically-operated gripping devices 35 in axial alignment with the guide tubes 1, 2 of each set F<SP>1</SP>, F<SP>2</SP> mounted on a plate 6 which is movable under the action of a ram 7 to feed the work forward to the dies or push pointing mechanism. The rams for the gripping devices 35 are coupled to the air supply for the ram 7 through a pipe 49, Fig. 4, forming part of a telescopic tube and the ram 7 is prevented from moving forward by a latch 5 until after the work has been gripped with a predetermined pressure. The latch 5 has an adjustable spring-loaded plunger with a tapered end engaging a notch in the connecting rod 10 of the ram 7. The plunger may be lifted to release the ram 7 either by pneumatic pressure or by the load on the ram reaching such a value that the plunger is forced back due to its tapered end. The central guide tube 2 of each set is fixed on a frame member 4 and supports the tubes 1 which are slidably guided in bearings 3A mounted on the tube 2. The tubes 1 carry the plate 6 at their forward ends and act as slidable guides. Common pivot pins 13, 14 on the plate 6 carry the gripping devices 20, 21, Fig. 4, on arms 15, 16. The upper arms 16 are rotatably fixed on the pin 14 which is yieldingly held against rotation by a crank arm 23 and a spring-loaded plunger 29 so that the gripping devices are normally held free from engagement with the work. The bodies of the gripperoperating rams 35 are connected through hooked links 44 to the lower arms 15, and gripping members 21 and the pistons 37 are mounted on the upper arms 16. In operation, pneumatic pressure in the top of the ram 35 raises the lower gripping members 21 and lowers the upper members 20 to engage the work and after the predetermined pressure has been reached the latch 5 releases the ram 7 and the grippers are moved forward to feed the work. On release of pressure the gripping members 20, 21 are released by springs (not shown). Specifications 569,934, 578,076, 626,846 and 634,663 are referred to.