Patent GB-692434-A (GB)
Title: Machine for buffing tyres
IPC: B29B17/02
Filed: 1950-06-16
Abstract: 692,434. Buffing tyres. HAWKINSON CO., P. E. June 16, 1950 [Sept. 16, 1949], No. 15147/50. Class 60. A machine for buffing tyres prior to retreading includes means for rotatably mounting a tyre casing on an axis carried by a standard, the standard being carried by a turntable rotatably mounted on a base, and a pair of rotatable buffing wheels coaxially mounted in spaced relation to one another on a rotary shaft, the latter being mounted for movement radially toward and away from said tyre, one of said buffing wheels being positionable in a vertical plane extending through the tyre centrally of the sides thereof, and means for simultaneously axially shifting said wheels to move the first mentioned wheel out of its registration with said vertical plane and the second mentioned wheel into registration therewith. A wheel 18 carrying a tyre casing 19 is rigidly secured to a shaft 17 journaled in a spindle casing 16; the shaft 17 is rotated by a motor 21 through a multiple speed clutch and gearing in a housing 22, a drive shaft 23, gearing in a housing 24 and worm gear in housing 20. The spindle casing 16 is carried by a slide 11 movable, by a screw 13, transversely of a block 9 carried by a standard 6, the block being held in desired position on the standard by screws 10. The standard 6, which has a strengthening rib 8 is connected to a bracket 4 by headed bolts 7 passing through a slot 5 in the bracket 4. The latter is secured to a turntable 2 mounted on a vertical stub shaft 3 on the machine base 1. The base 1 is provided at one end with a pair of guide members 25 rectangularly notched to support a slide 26 movable towards and away from the turntable 2, the slide 26 having a rack 29 engaged by a pinion 30 on a shaft 31 the upper end of which carries a ratchet lever 34 having a pawl 35 which can be set to have the ratchet in neutral or right and left operative positions. A circular base plate 36 mounted on the slide 26 rotatably supports a pedestal 37 to the upper end of which is secured a platform 38. A lever 40 for turning the pedestal 37 is pivotally secured at 42 to bracket 41 on the platform 38. An index rod 43, loosely connected at its upper end by bolt and slot connections 44 to the intermediate portion of the handle 40, projects downwardly through an opening in the platform 38 and its lower end is adapted to be received in an indexing aperture in the base plate 36. Intermediate its ends the index rod 43 has a camacting lug 46 adapted to operate a brake lever 47 pivoted at 48 to a bracket 49 secured to the pedestal 37; the lower end of the brake lever 47 has a friction lug 50 engageable with the outer peripheral surface of the stationary circular base 36. Limited upward movement of lever 40 from its lowest position disengages the rod 43 from the indexing aperture and permits turning of the pedestal 37 relative to the base plate 36; continued upward movement of the lever 40 causes the brake to be operated to hold the pedestal in any desired position. A pair of buffing or abrading wheels 51, 52 are mounted on a shaft 53 journaled in a sleeve 55 slidably mounted in a housing 56; one wheel 51 is covered with coarse abrasive material and the other 52 with relatively fine. A pulley 64 is mounted for axial movement on the end of the shaft 53 projecting from its bearing sleeve 55; a circumferential channel 66 in the pulley 64 is engaged by the inturned end 68 of a bracket 67 secured to the housing 56, so as to maintain the pulley at a predetermined distance from the end of the housing 56 irrespective of the position of the axially movable bearing sleeve 55 with respect thereto. The housing 56 is supported from the platform 38 by a rigid bracket 70. The buffing wheels 51, 52 are driven by belts 71 running over the pulley 64 and over a pulley 72 on the shaft of a motor 73 mounted on the platform 38 and controlled by switch 82. The motor 73 also drives an exhaust fan, contained in a fan housing 74, which draws material buffed from the tyre through a hood 75 partially enclosing the buffing wheels 51, 52 and blows it through an exhaust stack 76. With the turntable 2 in the position shown in Fig. 1, the tyre 19 lies in a vertical plane extending through the centres of pivotal movement of the turntable 2 and of the pedestal 37 ; one or other of the wheels 51, 52 may be selectively moved into or out of this vertical plane by axial movement of the bearing sleeve 55 which has a rack 77 thereon engaged by a toothed gear segment 78 operated by a shifter handle 79. In preparing the tyre for the application of the new tread material the coarse buffing wheel 51 is initially used; after the tyre has been placed in true round, the relatively fine buffing wheel 52 is used to obtain a better bonding and vulcanizing surface for the new tread stock. A convex arcuate profile may be generated on the crown surface of the tyre 19 by oscillating the turntable 2 about its pivot 3; the pedestal 37 is locked in correct position by engagement of the index rod 43 in aperture 45. For buffing of the side edges of the crown portion of the tyre, the correct angular position of the tyre is obtained by adjusting the turntable 2 about its pivot, and the correct angular position of the buffing mechanism is obtained by disengagement of the index rod 43 from the aperture 45 and adjustment of the pedestal 37 which is locked in the desired position by extreme upward movement of the lever 40.