GB253928A - Improvement in crank shaft lapping machine - Google Patents

Abstract

253,928. Player, S. June 17, 1925, [Convention date]. Block, rubber, and like apparatus; spindles and the like, treating: spindle-mountings. - A machine for lapping crank shafts consists of a base 20 upon which are mounted a headstock 23 carrying a shaft 26 provided with a centre 41, and a tailstock 24, adjustable on ways 25 and carrying a centre 43. The centre 43 is mounted in a sleeve 44 running on ball bearings 47, 48 in a sleeve 46, which is slidable in the tailstock 24 and is pressed up to the work by a spring 51; a cord 53 secured to the sleeve 44 passes over pulleys 54, 55 to a counter-weighted pedal lever 56, depression of which withdraws the centre 43 from the shaft S. The shaft 26 is driven by a belt from a shaft 30 which is provided with a friction clutch 35 controlled by a handle 38 and a rod .37, which, when the machine is in operation, lies below the lever 56, preventing depression thereof. The crank shaft S is reciprocated axially during lapping by a pivoted fork 62 having rollers engaging a grooved member 60 on the shaft 26. the fork being rocked, through a rod 65 by a crank pin 66 adjustably carried by a plate 69, which is driven through chain gearing 72, from the shaft 30. The lapping-members are mounted on shafts 77, 78 supported by frames 75, 76 and each comprises a hub 85 with a depending arm 84, the hub being secured by a screw 86 to a bushing 80, the bushings being mounted by bearing inserts 81 on the shafts 77, 78. Oil may be supplied by a tube 87, and the arm 84 also has therein an oil passage 90 for the lower bearing thereof. The arm 84 has pivoted at its lower end 93 a lap holder 91 forked to receive the part 93, a bearing brushing 94 being provided, and the parts being held in correct position by a stud 97 and caps 95,.96. The lap holder has a cross bar 100 to which are pivoted a pair of levers 102, 103 moved together or apart by toggle levers 104, 105, and the lever 102 carries the lower lap 112, which is centred by a pin 115 with allowance for a small amount of angular movement, and the lever 103 carries the upper lap 113 on the spherical end of an adjustable stud 120 mounted in the lever; an oiling device 122 is provided. The laps have a central recess in which may be placed a felt pad, and are of such axial length that the reciprocation of the crank shaft causes the whole length of the bearing portion to be lapped. The main bearings, as well as the crank pins, may be lapped simultaneously.