Patent GB-508411-A (GB)
Title: Method of and means for use in the surface grinding of the dents on dismounted flat bars used in carding engines
IPC: B24B19/18
Filed: 1938-03-19
Abstract: 508,411. Grinding card teeth. DRONSFIELD, J. March 19, 1938, No. 8497. [Class 60] In the surface grinding of the dents or teeth of dismounted flat bars of carding engines, a number of bars 20 are mounted with their transversely bevelled or sloped end faces 20x held in contact with the internal cylindrical faces 14 of two carriers 13, 13x mounted on a rotatable shaft 10, the carrier 13x being adjustable along the shaft to suit the length of the flat bar 20, and the bars being held by clamps 16 operated by screws 18, whilst spaced pins 19 in the face 14 serve to locate the bars. The shaft 10 is partially rotated intermittently to bring each flat bar to a position for grinding, wherein the outer face of the dents lies in a horizontal plane above a grinding-roller 31, the position making allowance for the cant of the bar due to the bevelled end faces, and the rotation of the shaft 10 is brought about by means of a ratchet-wheel 21 actuated by a pawl 41 and steadied by a weighted brake band 27 passing over the wheel; a wheel 24 secured to the wheel 21 and having notches therein engaged by an adjustable spring detent 26 also serves to retain each flat in grinding position. The grinding-roller 31 is mounted in bearings 32 reciprocated in slides 34, transversely of the axis of the roller, by connecting rods 35 moved by eccentrics 36 carried by a shaft 37 so as to carry the roller across the ends of the dents. The pawl 41 is pivoted at 42 to one of the bearings 32 so that as the grinding-roller moves in its backward stroke, the pawl rotates the wheel 21 and the carriers 13, 13x to bring another bar 20 into grinding position, and the correct positioning of the parts to suit the bevel and width of the flat bar is ensured by the use of spacing packings 39 located between the ends of a structure 38 carrying the shaft 37 &c. and brackets 40 on the machine frame. The shaft 37 is driven from a pulley 49 through a pulley 52, pulley 54, gearings 56 .. 58 and a gear wheel 60, and the grinding-roller is driven from the pulley 53. The grinding-roller is fed upwards slowly during grinding by means of internally threaded worm wheels 63 driven by worms 64 on a shaft 65 and engaging screw threaded extensions 62 on the slides 34, the shaft 65 being driven, through a ratchet-wheel 66, by a pawl 68 on an arm 67, which is oscillated by an eccentric boss 69 on a casing 76 driven very slowly through epicyclic gearing 70 .. 75 by the shaft 37. A stop motion is provided for stopping the feed and then stopping the machine when all of the dents have been ground to the desired extent as governed by the number of teeth the wheel 66 is fed by the pawl. When the last tooth has been fed, the pawl falls into a gap 66x in the wheel 66 and then engages a ratchet wheel 79 free to rotate, under friction of a plunger 80, on the shaft 37, so that grinding now proceeds without feed until the last tooth of the wheel 79 is fed, when the pawl falls into a gap in the wheel 79 and engages a tooth on a wheel 81. The wheel 81. is free on the shaft 37 and is connected by an arm 82, link 83 and arm 86 to a shaft 88 carrying a lever 89, 90, the arm 90 engaging behind a stop 93 on a spring pressed bar 92, which shifts a belt fork to move the main drive belt from the fast pulley 49 to a loose pulley 49x when the bar is released by movement of the arm from the stop 93. A handle 89 serves for manual operation of the stop gear, and a handle 98 serves to start the machine by moving the belt on to the fast pulley. Slight endways movement is given to the grinding-roller by mechanism 101. In operation, the shaft 37 and the eccentrics 36 are rotated at such speed as to rotate the carriers 13, 13x, to bring all of the bars 20 under treatment about once in each halfminute, the grinding-roller being fed very slowly upwards until the stop motion operates to stop the machine. The flat bars before insertion in the carriers 13, 13x are tested in a tester T to find those with the longest and with the shortest dents ; this gives a measure of the amount of grinding required, and the ratchet-wheel 66 is set accordingly, the wheel 79 being set according to the length of time required for grinding without feed.