Patent GB-568524-A (GB)
Title: Improvements in and relating to abrasive drilling machines
IPC: B28D5/02
Filed: 1943-09-29
Abstract: 568,524. Grinding. PHILIPS LAMPS, Ltd., BERG, A. C. VAN DEN, and KENYON, H. Sept. 29, 1943, No. 16008. [Class 60] [Also in Group XXII] A machine for drilling diamond dies for wire drawing &c., wherein the drilling-tool is in the form of a steel needle charged with abrasive, for example, diamond dust and oil, has means comprising a grinding or lapping wheel, for restoring the shape of the drill as this becomes worn. The machine comprises a chuck 2 carrying the drill 1 and rotated in bearing supports 7 by a pulley and cord 6, the drill being aligned axially with the diamond 8 to be drilled, which is mounted on a support 9 carried by grooved rollers 10 mounted in a support 12 adjustable by screws 13, 14. The support 9 is pressed towards the drill 1 by a spring 16 held by a clamp 17 adjustable, to vary the tension of the spring, along a rod 18, and on the support 9 is a pin 20 engaging a guide slot in the support 12. The support 9 is moved away from the drill by a lever 22, one end of which engages the pin 20 and which is carried by a pivot pin 23 ; the lever has at the end remote from the pin 20 a pivoted section 25 urged by a spring 33 against an adjusting screw 26, whereby a screw 27 in the section 25 can be moved to contact at the desired radius with a face cam 28. The cam 28 is carried by a shaft 29 in a bracket 30 and is driven by a belt 32. The spring 33 is anchored at one end, and engages the pin 23, so as to press the screw 27 up to the cam 28, and the spring also passes round a screw 34. The pin 23 and the bracket 30 are carried by an arm 35, pivotally mounted on a shaft 36 in a fixed quadrant 37 having an arcuate slot to receive a clamping bolt 39, whereby the arm 35 may be secured in adjusted position in relation to the diamond support. The drill is ground to shape, after wear, by means of a grinding or lapping cylinder 56 ; the mounting for this comprises a transverse shaft 40 carried by the arm 35 and having thereon an arm 41 engaging the screw 34, and an arm 42 adapted to engage a face cam 48 ; a spring 43 tends to hold the arm 41 away from the pin 34. The cam 48 is mounted on a shaft 44 driven by a chain 47, and rotation of the cam rocks the shaft 40 to engage the arm 41 with the screw 34, and, through the lever 22 and pin 20, to retract the support 9 from the drill, the screw 27 also being lifted so that the cam 28 is inoperative. The cylinder 56 then is lifted, to engage the drill, by a second cam 49 on the shaft 44, which acts on a lever 50, which in turn engages the lower end of a column 52 slidable in a guide 53 and having adjustably secured at its upper end, by means of a clamp 54, a fork 55, in which the cylinder 56 is carried and rotated by a belt 60. The wear on the cylinder may be distributed by mounting the cylinder on a slide, so that the cylinder can be adjusted axially ; the cylinder also may be adjustable on a slide axially of the drill 1. The axial adjustment of the cylinder may be automatic and. operated by ratchet-and-pawl mechanism under control of the cam 49. Specification 568,527 is referred to.