Patent GB-971435-A (GB)
Title: Belt control
Inventor: SCHUSTER GORDON LOUIS
IPC: B24B21/00
Filed: 1963-08-23
Abstract: 971,435. Abrading. TIMESAVERS SANDERS Inc. Aug. 23, 1963, No. 33509/63. Heading B3D. . Apparatus for maintaining a belt in a desired path on a pair of rolls comprises a main frame, a first roll journalled on such frame, a secondary frame pivotally mounted on the main frame, a second roll journalled on said secondary frame, a pneumatically controllable device acting between said frames and operable to move the said secondary frame about the axis of its pivoted mounting to vary the relative position of the rolls, at least one air orifice positioned adjacent one end of the second roll and opening either in, or in alignment with, the circumferential surface of such roll so as, in operation, either to be obstructed or to be uncovered by the adjacent edge of a belt upon movement of the latter axially along the said second roll, such orifice being connectable to a source of suction or of air under pressure and also being so connected to said pneumatically controllable device that, in operation, a change in pressure at the orifice upon such obstruction or uncovering thereof will cause operation of said device to alter the relative position of the rolls and thus maintain the belt in its desired path. The apparatus may be used to maintain an abrading belt in a desired lateral position or to cause it to reciprocate laterally. An abrading belt 20 is trained round rolls 14, 18. The roll 14 is rotatably carried by the machine frame 12 and its shaft 34 is driven, e.g. by an electric motor through belts. The roll 18 is rotatably supported by shafts 90, 92 in a yoke 16 fixed to a shaft 46 rotatably mounted in a member 38 slidable in a housing 36 secured to a cross-bar 28 of the machine frame 12. A shank 56 welded to the slidable member 38 is connected at 60 to a lever 58 pivoted at 64 to the machine frame and having its free end pivoted at 72 to a double-acting pneumatic jack 66 pivoted at 76 to the machine frame, whereby the belt can be tensioned. A double-acting pneumatic jack 80 is adjustably connected to a shank 78 integral with one edge of the yoke 16. Orifices 94, 96 in the roll surface adjacent opposite ends thereof are connected through passages 98, 104 in the shafts 92, 90 to rotatable connectors 100, 102. Compressed air from a source 114 passes through a pressure regulator 110 and orifices 112, 120 respectively to the roll orifices 94, 96, the pressures in the two branches being communicated to pneumatic relays 108, 118. These are supplied with compressed air from the source 114 and their outputs are connected to opposite ends of the jack 80. If the belt creeps to one side, the corresponding roll orifice is covered during half of each rotation of the roll, and the resulting pressure increase operates the corresponding pneumatic relay activating the jack 80 to tilt the roll 18 to cause the belt to creep in the opposite direction. In a modification, the tilt roll has an orifice at one end only. Tilting of the roll is effected by a spring-loaded single -acting pneumatic jack. The spring urges the roll to a position in which the belt creeps towards the orifice. When the belt covers the orifice the jack tilts the roll in the opposite direction thus returning the belt. In another modification, the orifice 94b, Fig. 10, is separate from the roll 18b. In another modification, pneumatic relays are omitted. In another modification, Fig. 12, compressed air is supplied through pressure regulator 191 to the roll orifice 94 and to a single acting jack 180. Compressed air is also supplied through a pressure regulator 197 to the roll orifice 96 and to another single acting jack 181. A vacuum system may be used instead of a pressure air system.