Patent GB-580178-A (GB)
Title: Improvements in or relating to the internal grinding of metal moulds and other tubular bodies
IPC: B24B5/40
Filed: 1943-09-22
Abstract: 580,178. Grinding-machines. UNITED STATES PIPE & FOUNDRY CO. Sept. 22, 1943, No. 15571. Convention date, June 7. [Class 60] A machine for taper grinding the inner surface of a tubular body, described as a mould for the centrifugal casting of pipes &c. comprises means for rotating the body, and means for rotating and traversing a grinding-wheel, the speed of traverse of the wheel being uniformly increased or decreased. The machine comprises longitudinal girders 16, Figs. 2, 2a, secured together by ties 17 and carrying crossbeams 15, the work 10 being supported and rotated by units each mounted on a crossbeam and comprising two rollers carried by bearings 14 and driven by belts 19 from a shaft 21, which is driven, through a gear-box 23 by a motor 24. The grinding-wheel 25 is carried at one end of a long shaft 26 supported by spaced bearings in a tubular support 28, the end of which, remote from the wheel 25 is secured by a bracket 38 to one of two spaced cross-beams 34 forming part of a carriage 29 movable lengthwise of the work on wheels 30 running on tracks on the girders 16. The cross-beams 34 are adjustable, to adjust the vertical position of the grinding-wheel by sleeves 36 secured between the beams 34 and in threaded engagement with shafts 33 supported by pedestals 32 on the carriage 29 and rotatable by handles 37 ; the shaft 26 is driven by belts 41 from a motor 42 mounted on the carriage. The carriage is moved by a pistonrod 46 secured at one end to a bracket 47 on the carriage 29 and having at its other end a piston 48 operating in a cylinder 49, the movements of the piston being controlled by a reversing valve 51 operated by a handle 52 to control the supply and exhaust of fluid through pipes 53, 54 to the cylinder. In order to produce the taper in the bore, the speed of traverse of the grinding-wheel 25, which makes gravitational contact with the bottom of the bore, is varied uniformly by varying the exhaust passage for spent fluid from the cylinder 49 by means of a needle valve 56, Fig. 10, in the exhaust pipe 55 from valve 51. The needle valve is operated by a pulley 57 on the valve stem 58 operated by a belt 59 driven by a pulley 60, which is driven, through reduction gearing by an endless cable 68 secured at 70 to the carriage 29 and over a sheave 69 ; the speed of traverse thus increases in one direction, and decreases in the opposite direction. The wheel 25 and support 28 are supported, when the wheel 25 is withdrawn from the work 10 by a rest comprising a grooved wheel 72 adjustably mounted on a carriage 75 running on the tracks 31. Compressed air is supplied at the grinding point to remove dust &c. by a pipe 78 and dust is removed through a telescoping sleeve 82 connecting the pipe to an exhaust head 81 provided with a fan in a casing 84. In order to place the work on the rollers 12, a skid device is provided, comprising two rails 86, Fig. 4, pivoted at 87 at one end and at the other end secured to a rail 88 which may be raised or lowered by a piston in a cylinder 90 pivoted to a base 91 ; the work is positioned on the rails 86 with these horizontal and is then lowered on to the rollers 12 by lowering the rail 88 by means of the piston &c.