Patent GB-559447-A (GB)
Title: Improvements in or relating to rotatable broach holder
IPC: B23D43/06
Filed: 1943-02-17
Abstract: 559,447. Broaching-machines. LAPOINTE MACHINE TOOL CO., Ltd. (Lapointe Machine Tool Co.). Feb. 17, 1943, No. 2653. [Class 83 (iii)] A broaching machine in which successive broaching operations are performed on each work piece while in a single central broaching position has a broach holder mounted to rotate about a horizontal axis carrying a number of horizontal angularly spaced broaches which are brought successively to broach-delivery position by indexing movements of the holder. The work W, Fig. 11, is mounted in a transversely-movable holder 20 and after the first broach has been pulled through the work by the main ram while the work is at the working station T the work support is shifted transversely to a clearance position, Fig. 12, while the active broach B is returned to a return actuator mounted within the broach holder. This returns the broach to a position completely clear of the work. The broach holder is then indexed to bring the next broach into broaching position, the work returned to central position and the new broach advanced by the actuator until it is gripped in the main head after which the broaching cycle is repeated. A second work station T<SP>1</SP> acts as a loading station while the work in station T is being broached. The indexible broach-holder comprises annular end members 30 with surfaces resting on rollers 32, 33, one of the rollers being driven intermittently to index the holder by a motor M, Fig. 14. The members 30 have outward projections 35 connected by longitudinal beams which carry lateral guide pieces 37, Fig. 1, which slidably engage grooves 40 in the broaches B. The indexed positions are determined by an index plunger 44 engaging in one of a series of recessed blocks 42 in the head 30. The plunger is connected to a pivoted link 46 operated against a spring 45a by a solenoid 50. A central broach actuator 60 is slidable on guideways 61 with friction bars located at 63. A cross flange 65 on the actuators can engage the rear of a broach to move it forward till its reduced end engages in the main head. A latching plunger 70 coacting with a notch 74 in the broach may be actuated by an inclined slot in an axially-movable member 80 mounted in the actuator 60 and having limited lost motion therein. The member 80 is integral with a part 90 actuated by a hydraulic cylinder 93. Thus the movement of the cylinder to the left, Fig. 2, first takes up the lost motion and moves the plunger 70 into engagement with the broach, after which further movement carries the broach to its fully withdrawn position. Movement in the opposite direction first withdraws the plunger after which the broach is pushed into the main head by the projection 65. Automatic indexing is effected in proper sequence by the circuit shown in Fig. 14. The circuit of indexing motor M includes a switch S connected to lever 46 and the circuit of solenoid 50 includes a switch S' in parallel with a holding switch S<SP>2</SP> operated by lever 46. When the switch S<SP>1</SP> is momentarily operated the solenoid 50 is energized to free the holder 30 and switch S is closed to start up the indexing motor. The switch S<SP>2</SP> is also closed. After the required movement one of a series of projections 106 engages a lever 107 to disengage contacts 102, 103, to break circuit of solenoid 50 which opens switch S and stops the indexing motor so that the locking plunger 44 can snap into the next notch. After the indexing movement the fresh broach is moved to engage the main head.