Patent GB-190414351-A (GB)
Title: Improvements in Machines for Cutting Slots in Turbine Wheels and the like.
Inventor: RIDDELL JOHN
Filed: 1904-06-25
Granted: 1905-05-11
Abstract: 14,351. Riddell, J. June 27, A.D. 1903, [date applied fon under Patents Act, A.D. 1901]. Slotting ; shaping.-A machine for cutting buckets or slots in turbine wheels, discs, segments, &c. has a tool-holder 66, Figs. 11 and 12, clamped in a frame 5, which is rocked on its pivot 6 and at the same time is reciprocated vertically to cause the tool 67 to cut the necessary curved slot or bucket. The rocking movement is obtained from a crank-pin 11, while the vertical reciprocating movement is obtained from a cam 18 with which a howl 19 on the frame engages. The tool is rocked to maintain its cutting-face normal to the direction of cutting, and is slightly retracted after each cutting-stroke so that it may return through the slot without drag during the idle stroke. The work (not shown) is mounted on a spindle carried by a slide which is adjustable along the upper edge of a bracket 49, vertically adjustable by a screw 44 and a hand-wheel. The work is clamped in a vertical plane containing the axis of the toolholder by clamps (not shown) adjustable on the guide-strips 7, 8 of the frame 5. The crank-pin for rocking the frame is carried by a shaft 12, rocked by a pinion and segment 14, the segment being pivoted at 21 and slotted to engage a crankpin 29 of variable throw, which imparts a quick return to the tool. A rocking arm 33, pivoted at 34 to the framing, is linked to the segment and carries an adjustable wrist-pin 36 on which is a guide engaging an arm 38 to rock the tool to maintain it normal to the direction of cut. The arm 38 is secured to a sleeve 69, Fig. 17, in which the tool-holder 66 can be fed forwards by a screw 70 rotated by a train of wheels from a spindle 90 carried by the arm. The sleeve is mounted in a casing 73 carried by a block 64 which is clamped to the frame 5. On the casing is a cam 93, angularly adjustable by worm gearing 95 to vary the throw it imparts to a pawl arm 98, Fig. 18, pivoted on the spindle 90, the split pawls 99 engaging a ratchet-wheel on the spindle. The cam is graduated to indicate the amount of the feed. The movement of the tool and holder to withdraw the tool during the idle stroke and to return it at the commencement of the cutting- stroke is effected by fluid (preferably air) pressure, acting on an annular piston 71 on the sleeve 69. The fluid is controlled by two piston valves 100, 101, Fig. 18, which are depressed alternately by arms 108 on a ring loosely mounted on the casing 73 and having adjustable lugs engaged alternately by the end of the spindle 90. The depression of one valve (shown as 100) admits fluid pressure to one side of the piston, and below the other valve, which is thus raised to open the other side of the piston to the exhaust 106, thus advancing or withdrawing the tool and holder. The cam 18 may be changed for different shapes of slots and may be adjusted angularly to cut unsymmetrical slots. Each slot may be cut in two steps, the work being adjusted between the steps, so that the sides of the slots are not concentric.