Patent GB-661214-A (GB)
Title: Improvements in or relating to grinding machines
IPC: B24B7/16
Filed: 1949-02-15
Abstract: 661,214. Grinding springs. BETTS, R., and MIDGLEY, S. Feb. 9, 1950 [Feb. 15, 1949], No. 4064/49. Class 60. A machine for grinding the ends of helical springs and the like so as to give the springs a uniform length and flat end surfaces comprises a pair of similar but oppositely directed side-face grinding wheels coaxially mounted upon the same driving shaft, the one wheel being fixed on said shaft and the other wheel being slidable along but rotatable with said shaft, and a magazine for carrying the springs to be ground between said wheels and capable of being driven at reduced speed from the grinding wheel shaft, means being provided for adjusting the positions of said slidable wheel and said magazine relatively to each other and to the fixed wheel in accordance with the thickness of the magazine and the wear on the grinding wheels. The machine includes a base plate 10 having an upright portion at one end formed as a vertical slide bed 11 upon which a saddle 12 is vertically adjustable by means of a hand operated screw feed 13. An electric motor 14 carried by the base plate 10 drives through a belt 17 a vertical shaft 15 having keyed thereon an upwardly directed side-face grinding wheel 21; the shaft 15 has an upward extension 22 over which a hollow coaxial shaft 23 fits slidably but not rotatably by means of a key 24. The hollow shaft 23 is mounted in bearings carried by the vertically adjustable saddle 12 and carries at its lower end a downwardly-directed side-face grinding wheel 25. The shaft 15 drives, through worm reduction gearing 18, 19 and cross shaft 20, a vertical shaft 16, on the upper end of which is splined or otherwise slidably but not rotatably mounted a disc 26 supported by a bracket 27 vertically adjustable on a pillar 29 extending upwardly from the base 10. The disc 26 has a thickness less than the length of the springs to be ground and has a circumferential series of perforations 30 each provided with a bush 31 retained by a set-screw 40, the apertures in the bushes providing an easy sliding fit for the springs. The bracket 27 serves as a closure for the lower ends of the perforations 30 in the disc 26, but is cut away at 32 to accommodate the periphery of the lower wheel 21, and has also a discharge slot 33 through which ground springs drop into a receiver. To assist the entry of the springs between the grinding faces, a guide plate 34 having an oblique under-surface is provided; a similar guide plate 36 exercises a controlling effect on the springs as they leave the grinding face. Small rollers may be used to control the entry and exit of the springs. To protect the mechanism in the event of a spring becoming jammed, the worm reduction gear 19 through which the shaft 16 is driven includes a slipping clutch in the form of a leather or like friction washer 37 disposed between the worm wheel 19 and a shoulder or flange 38 on the shaft 16, the worm wheel 19 being rotatably mounted on the shaft 16 and being pressed against the washer by means of lock nuts 39. When springs of small diameter are to be ground, each bush 31 may be formed with more than one aperture.