Patent GB-695733-A (GB)
Title: Improvements in or relating to polishing machines
Inventor: DACKOR EMIL
IPC: B24B21/00
Filed: 1951-01-30
Abstract: 695,733. Grinding turbine blades. THOMPSON PRODUCTS, Inc. Jan. 30, 1951, No. 2303/51. Class 60. A machine for polishing turbine blades and like workpieces is provided with one or more units each comprising a workholder 112, Fig. 4, arranged to hold a workpiece B between a pair of abrasive belts 34, means for recipirocating the workholder and workpiece, and means for reciprocating the belts in a direction normal to the direction of movement of the workpiece. The units 20, Fig. 2, are arranged in spaced relation around the periphery of a table 10 which is intermittently rotated by a motor 14 and is stopped automatically as each unit reaches the operator's station to permit a new workpiece to be substituted for one which has been polished. Each workholder 112 consists of two jaws pivoted, as shown in Fig. 15, at the lower end of a hollow rod 92 journaled in a slide 26, Fig. 4, which is reciprocated vertically on an upright 22 by means of a power-driven pulley 50 acting through gearing and adjustable crank-and-connecting-rod mechanism. The jaws are controlled by a pin 100 which slides in the rod 92 and, when forced outwardly by a spring 103, engages recesses 109 in the jaws to force them on to the workpiece ; withdrawal of the pin 100 to permit opening of the jaws by a spring 116 is effected by a shaft 37, Fig. 4, acting through links and cranks. The workpiece, when gripped by the jaws, extends between the horizontal portions of the two belts 34. Each belt is led from a spool 117, Fig. 4, downwardly and forwardly over rollers 130, 131, thence over the horizontal rollers 136, 137, Fig. 5, and over further rollers to a roller 143' which is intermittently driven by ratchet mechanism from the shaft 37 so as to pass the belt to a take-up roller mounted on the shaft of the spool 117. A rubber pad 32, Fig. 5, which is disposed on the outerside of the horizontal portion of each belt, is movable to press the band against the workpiece and then reciprocate the band horizontally. Each pad is carried by a holder 33, Fig. 7, connected by pins 159 engaging slots 160 to two spring-pressed rods 155 mounted in longitudinal holes 150, 151 in a member 149 slidable in a fixed sleeve 147. Movement of the slide 149 to retract the pad is effected from the shaft 37, Fig. 4, through levers 172, 177 and links 182, 184. Reciprocation of each pad is effected from a power-drive acting through a belt 199, Fig. 4, pulleys 198, 200, and levers upon a bell-crank 193 which is connected to the holder 33 by a link 212 and a lever pivoted centrally in a longitudinal hole in the slide 149. Opening of the work clamp and movement of the pads 32 from the belts are effected each time a unit 20 arrives at the operator's station. For this purpose, a rod 40 journaled in each unit is rotated when a cam follower 41 on the rod engages a cam 42, Fig. 2, arranged on the fixed frame 15 at the operator's station. Rotation of the rod 40 acts through gearing to rotate the shaft 37 which, as described above, opens the jaws of the workholder and retracts the pads 32. When the cam follower leaves the cam 42, the workpiece is automatically clamped and the pads 32 press the belts on to the workpiece; the workpiece is then carried around on the table while the workholder is reciprocated vertically and the pads reciprocate the belts horizontally. Each time the shaft 37 is rotated by the cam 42 it acts through a linkage to operate the ratchet mechanism for feeding the belts on to the takeup spools and thereby present fresh operating surfaces to the workpiece.