Patent GB-662446-A (GB)
Title: Improvements in or relating to abrasive cut-off machine
IPC: B24B27/06
Filed: 1949-01-14
Abstract: 662,446. Severing by grinding. AMERICAN CHAIN & CABLE CO., Inc. Jan. 14,1949, No. 1127/49. Class 60 [Also in Group XXIV] An abrasive cut-off machine comprises means which is operable to effect a cycle including the feed of .the work to a support, clamping of the work against the support, and starting movement of an abrasive wheel 16 towards the support, and then stops, and means controlled by the wheel when it has cut through the work to re-start the means for carrying out the cycle. The work is supported on a pair of V-blocks 13, 14, Figs. 3 and 4, which are mounted on a bed 12 and separated by a slot 15 for the passage of the disc 16. The wheel 16 is clamped on a shaft 18 mounted on the forward end of an arm 24 which is pivoted at 25 on a bracket 27a adjustably mounted on the upper end of a vertically-movable post 28. A second bracket 27 on the post mounts a motor 23, Fig. 2, which has its shaft aligned with the pivot 25 and drives the shaft 18 through belts and pulleys. During operation, the disc is moved crosswise of the machine by pivoting the L-shaped foot 40, Fig. 2, of the post at 41 and employing an eccentric 49 driven by a motor 48 to rock the post vertically, the upward movements being assisted by a spring 42. The disc 16 is enclosed by a housing 240, Figs. 2 and 4, having a slot in one side wall for the vertical adjustment of the shaft 18. Mounted in the base 11 of the machine is a cam shaft 52, Fig. 3, which carries cams 68, 69, 70, 71 for controlling, respectively, rocking movement of the arm 24, opening and closing of work clamps 209, 210, Fig. 14, on a work-feeding slide 112, opening and closing of work clamps 120 associated with the V-blocks 13, 14, and the operation of the work slide 112. The shaft 52 carries a pulley 56 which is connected with the shaft through a onerevolution clutch 72 (see Group XXIV) and driven by a belt from a pivotally-mounted motor 59, Fig. 2.. The clutch 72 is controlled by a solenoid 231b, Fig. 4, which, when energised, moves a pawl 231a from latching engagement with a shoulder on the clutch so that the shaft is driven through one revolution when the pawl is again operative. The solenoid 231b is energised when, after cutting through the work, the disc 16 contacts a button 232 located below the V-blocks on an arm 233 at one end of a bent rod 234, 236, Figs. 3 and 4; the rod is then turned against the action of a spring 238 so that the portion 236 closes a switch 237 in circuit with the solenoid. The rocking movement of the arm 24 is controlled by the cam 68, Figs. 3 and 4, acting upon a vertical rod 79 which passes at its upper end through a collar 86 pivoted to the arm 24. The rod 79 is adapted to be locked to the collar 86 in any longitudinal position by toothed members engaging opposite toothed faces of the rod under the control of a solenoid 91. The teeth on opposite faces of the rod are relatively offset one-half the width of a tooth, and the arrangement is such that, each time the solenoid is energised or de-energised, the collar 86 and arm 24 move downwardly on the rod to the extent of one-half the width of a tooth; a jog push-button is provided for energising the solenoid when it is desired to lower the wheel on the rod 79. The work slide 112, Fig. 14, is slidable along the surfaces 182, 183 of a U-shaped way 113, being held thereto at each side by tapered gib plates 186, one of which is adjustable. Housed between the way 113 and slide 112 is a cylinder 163, the piston rod 175, Fig. 7, of which is connected to the slide. The movement of the piston rod and slide is controlled by the supply of fluid to opposite ends of the cylinder 163, and this, in turn, is controlled by the action of a piston in a cylinder 151 under the control of the cam 71. An end stop for limiting the return movement of the slide is in the form of an adjustable screw 192, Figs. 13 and 14, mounted on a bracket 191 adapted to be bolted in any one of a number of spaced longitudinal positions along the way 113. The upper face of the way 113 is slightly inclined so that, as the slide 112 moves towards the V-blocks, the work is raised from contact therewith and does not wear their upper faces. A guard in the form of two inverted U members 251, 252, Fig. 7, is mounted over the way 113, the slide 112 having a through-passage 253 so that it may pass over these members and the member 252 being hinged to facilitate access to the end stop 192. The work clamp on the slide 112 comprises replaceable jaws 209, 210, Figs. 13 and 14, bolted to the opposed faces of blocks 201, 202 which are, respectively, fixed to the slide and carried on one end of a vertically-pivoted lever 203 on the slide; the blocks 201, 202 are adjustable on their supports transversely of the work. The lever 203 is operated on by a spring 206 to urge the jaw 209 into gripping position, and it is moved to the .release position by the cam 69; this cam acts upon a vertically-movable fork 103 to rotate an eccentrically-mounted rod 109 which, through a roller 224, causes a bell-crank 221 to engage a projection 219 on the lever 203. The work clamp associated with the V-blocks consists of the hooked upper ends 120, Figs. 3 and 4, of a pair of vertical rods 121 which are moved between gripping and release positions by the cam 70 acting upon lever mechanism including a spring 141 for preventing the gripping pressure from exceeding a pre-determined maximum. A motor-driven pump in the base 11 pumps coolant through pipes 246, 247, Fig. 2, to a nozzle 248 extending through the front of the housing 240. Operation. The various motors are energised and it is assumed that the disc 16 in its downward movement under gravity, as permitted by the cam 68, has just cut through the work which is then gripped in the V-blocks by the clamps 120. The disc next engages the button 232 so as to energise the solenoid 231b to set the cam shaft 52 into rotation. As a result, the cam 68 operates, through the rod .79, to raise the arm 24 and disc 16, and later the cam 71 acts through the hydraulic mechanism to shift the work slide 112 back until it engages the stop 192. At this time, the cam 69 rocks the bar 109 to permit the spring 206 to cause the jaw 209 to co-operate with the jaw 210 to grip the work, and the cam 71 then causes the slide to move forwardly with the work to the V-blocks. The cam 70 has already released the clamps 120 from the cut-off piece of the work, with the result that the advancing work on the slide pushes such piece from the V-blocks and is, itself, positioned for the next cut; the cam 70 then again operates the clamps 120 and the cam 69 releases the clamps 209, 210. The cam 68 is then in position so that it no longer supports the rod 79 and the arm 24 with the entire cutter assembly falls under gravity, as controlled by a dashpot 32 acting on the bracket 27a, and the disc 16 cuts through the work; in this movement, a weight 263, Fig. 2, on the fore end of the arm 24 acts, with the weight of the cutter assembly, to overcome the counterbalance weight 26 on the rear end of the arm. At the time when the cam 68 permitted the latter operation, the cam shaft 52 has rotated through one revolution and is stopped by the pawl 231a, but the disc 16 continues its cutting action until it cuts entirely through the work and engages the button 232 whereby the solenoid 231b is energised to restart the shaft for another cycle. Should the disc 16 become so worn that it does not engage the button 232, an extension 81, Fig. 4, on the lower end of the rod 79 closes a switch 82 when the rod moves downwardly so as to energise the solenoid 91 controlling the latching of the arm 24 to the rod 79; the arm 24 with the disc 16 then move downwardly relatively to the rod 79 to an extent sufficient for the disc to contact the button 232. Specification 514,300 is referred to.