Patent GB-722286-A (GB)
Title: Drawbench with one or more longitudinally moved draw trolleys
IPC: B21C1/28
Filed: 1952-05-28
Abstract: 722,286. Drawing. KRIEDLER, A. May 28, 1952 [June 5, 1951], No. 13498/52. Class 83 (4). A drawbench having one or more carriages circulating on an endless chain the gripping members on the carriages being closed by stops on the bench and on the carriage at the beginning of the bench and being opened at the end of the bench is characterized in that a power source is disposed on the closing mechanism for the gripping members and is brought into operation to close the grippers by the cooperation of stop members. A drawing carriage 1 carrying two jaws 2 movable along oblique guides by means of a lever 3 is pivotally mounted in a downwardly projecting bearing 4 on the carriage. The lever engages a pin 6 in a vertical recess 7 in the gripping jaws 2. A spring 9 attached to the lever and to a downward extension on the bearing gives a toggle latch action to the lever. The carriage also has a pedestal bearing 10 carrying a jawopening lever 11 the lower arm of which has a pin 13 engaging a recess 14 in the jaws 2. The levers 3 and 11 are offset relatively to one another. The carriage is carried along continuously by the endless chain 16 of the drawbench 15 so that it moves along the upper portion of the bench on the drawing stroke and upon a lower rail 17 on the return stroke. Stops 18 and 19 on the bench extend into the paths of the levers 3 and 11 respectively. As the carriage swings into the direction of drawing the jaws encompass the pointed end of the work 20 and the lever 3 strikes the stop 18 and is reversed to close the jaws 2. Upon completion of the drawing operation the lever 11 engages the stop 19 and the jaws are opened and the work removed. In another embodiment the toggle lever 3 is pivotally mounted in an eye 21 on the carriage and the pin 6.engages the vertical recesses 7 in the jaws 2. Percussion rods 22 carried by two rollers mounted in a pedestal bearing 24 on the carriage are also mounted on the pin 6. In place of the stop 18 a percussion device is disposed on the drawbench and comprises a pedestal 25 supporting a shaft 27 which carries a spring-loaded lever 28 at one end and a hammer 30 at the other. A spring-loaded locking bolt 32 engages a locking disc 31 on the shaft 27 and a release bolt 34 is connected by a yoke 35 to the bolt 32. The release bolt has an oblique surface 36 protruding into the path of a stop 37 on the carriage. In operation when the stop 37 engages the oblique surface of the bolt 34 the bolt moves to the left and carries the locking bolt 32 with it whereby the locking disc is released and the spring-loaded hammer strikes the rods 22 and the jaws 2 immediately seize the work. On further movement of the carriage the pedestal 24 engages the hammer and returns it to its initial position and the locking bolt 32 once more engages the disc 31. At the end of the drawing operation the lever 3 engages a stop and opens the jaws. In a further embodiment the lever 3 is spring-loaded by a spring 38 (Fig. 7) and one arm of a spring-loaded latch 40 in the form of a bell-crank lever, engages in a sear disc 44 mounted on the hub of the lever 3. The other upwardly extending arm of the latch 40 engages a stop 45 on the drawbench to release the latch from the sear disc and effect the closing of the jaws. In a still further embodiment two electromagnets 46 and 47 are coupled to opposite ends of the lever 3. For closing the jaws the magnet 47 receives current from a contact on the drawbench and similarly the magnet 46 opens the jaws at the end of the drawing operation. The magnet 46 may be replaced by a mechanically operated impact device.