Patent GB-481068-A (GB)
Title: Improvements in and relating to vertical tapered spline broaching machine
IPC: B23F1/08
Filed: 1937-05-20
Abstract: 481,068. Hydraulic broaching-machines. TRIGGS, W. W. (Lapointe Machine Tool Co.) May 20, 1937, No. 14031. [Class 83 (iii)] A vertical hydraulic broaching machine particularly for cutting a number of splines in a tapered hole has a reciprocating broach and a work support which is moved transversely by hydraulic means to withdraw the work at the end of the cutting stroke, the work being then indexed and returned to working position at the end of the return stroke. A guide member 14 supported on a front column 12 guides a reciprocatable platen 15 carrying a table 17 which is indexable about an inclined axis so that the spline which is being cut is in a vertical position. indexing is effected by a worm gearing 18, 19 operated from a motor M through index mechanism 20, change gears 20a shaft 21, and bevel gearing. A sliding connection 25 permits the work table reciprocating movement which is effected by a hydraulic cylinder 28 operating the platen 15, the movement towards the broach B being limited by a stop 29. Indexing is controlled by a rod 32 operated through lever mechanism, Fig. 3, from a bracket 30 secured to the platen, the movement being effected when the platen is shifted to withdraw the work from the broach. The hydraulic circuit is shown in Fig. 4. A small pump 38 fed from the reservoir R delivers fluid to a valve V connected by lines 33, 34 to the platen cylinder. A discharge pipe 37 from the valve passes fluid through a filter 41 and round the casing of the main pump 40 to lubricate and cool the same. The delivery pipe 36 may also communicate with the line 37 through a relief valve 45. The spindle 50 of valve V is connected through lever mechanism, Fig. 4, to upper and lower roller-carrying lever arms 61, 54 respectively, adapted to coact with cam surfaces on a member 65 secured to a rod 66 moving with the ram 70. At the ends of the stroke one of the cam surfaces engages its corresponding roller to reverse the valve. The broach B is secured at its lower end in a holder 71 and slides in a broach guide 72, Fig. 8, whose upper end extends through and is secured by a screw in a bushing 73 in a fixed bracket 74 while the lower end rests in a fixed socket below the platen 15. To change the work, the broach is lowered and the broach guide withdrawn upwardly through the bushing 73. The ram piston rod is connected to a cross-head 83 connected by rods 84 passing loosely through the lugs 86 to lugs 85 located one on either side of the main cylinder at the upper end of the ram thus reducing the overall height of the machine. The pump 40, preferably of variable displacement type and driven by a separate motor, supplies the main cylinder through a valve C which is controlled by a rod 110 and other lever mechanism, Fig. 4, from a handle 115. The valve may also be actuated automatically by the member 65 which coacts with collars 125, 126, on a sliding rod 122 forming part of the lever mechanism. One of the valve ports is connected to the exhaust through a needle valve 132 which imposes a back pressure on the downward stroke of the ram. In operation the work having been positioned the broach is moved downwardly on the cutting stroke towards the end of which the cam surface 63 reverses the valve V and shifts the platen to withdraw the work and start the indexing mechanism. On completion of the downstroke the block 65 engages the collar 126 to shift the valve C whereupon the broach is returned to its upper position. A spring toggle device acts on the lever 114 and a slotted connection is provided in the link 110 so that, before operating the valve the link 113 is moved sufficiently to break the toggle and ensure a quick change over of the control valve.