Patent GB-996636-A (GB)
Title: Improvements relating to the printing of flat stock
IPC: B24B21/12
Filed: 1963-02-27
Abstract: 996,636. Polishing. MIDWEST SUPPLY & MFG. CO. Feb. 27, 1963 [Nov. 27, 1962], No. 7955/63. Heading B3D. Flat stock finishing apparatus of the type having a rotatively driven abrasive member, means to feed the stock past the member in a plane paralleling the axis of rotative drive of the latter for a finishing operation on the stock by the member and a rotative backing roll to directly sustain the stock against the member during the feed and finishing operation comprises means to support the backing roll in a position in which the backing roll axis is forward relative to the drive axis of the member in respect to the direction of feed of the stock. Apparatus for polishing the top surface of a metal sheet S includes an endless abrasive belt 16 passing round a contact roller 18. Feed-in pinch rolls 12 and discharge pinch rolls 14 are driven by reversible motor means, so that they may be unidirectionally driven for a single pass of the sheet or reversibly driven for multiple passes prior to discharge by the rolls 12. A billy roll 20 is journalled on a supporting structure which maintains its axis at a uniform vertical distance from that of the contact roller 18 such as will properly receive the sheet S for the preservation of desired grinding pressure. The support includes an actuator 24 reciprocable, in a plane paralleling that of the sheet feed, by a pneumatic cylinder 40 controlled by a valve 44 actuated by a solenoid 48, the speed of movement being controlled by a valve 46. A guide 36 on the actuator 24 rides on an anti-friction roller 34 carried by a bell crank 32 operated by a cylinder 30. For location of the end positions of the actuator 24, the latter carries a lug 47 co-operating with stops 102 simultaneously oppositely adjustable on an adjustable slide 98. Automatic control means includes photoelectric units 50, 56 comprising light sources 52, 58 projecting beams B, B<SP>1</SP> on to photo-cells 54, 60. Operation (single pass).-Control switch 64 is placed in the position shown with contacts a open and contacts b closed. The billy roll 20 is in the position shown in full line. The following cycle ensues. (i) When the leading edge of the sheet S enters the beam B, unit 50 closes contacts 62, thus (1) energizing timing relay 74 and (2) energizing control relay 80, closing contacts 80<SP>1</SP>. The leading edge of the sheet travels under contact roller 18 and rides up over the crown of the billy roll 20, whereby grinding pressure is exerted on the sheet. (ii) After an interval, sufficient for the leading edge of the sheet to reach the rolls 14, contacts 74<SP>1</SP> of timing relay 74 close, thus (1) energizing solenoid 48 moving billy roll 20 to the dotted line position, the roll maintaining grinding pressure during its movement, and (2) energizing timing relay 82, instantaneously closing contacts 82<SP>1</SP>, establishing holding circuit for solenoid 48 around contacts 74<SP>1</SP>. (iii) When the trailing edge of the sheet S leaves the beam B, unit 50 opens contacts 62, thus (1) de-energizing timing relay 74, instantaneously opening contacts 74<SP>1</SP> and (2) deenergizing control relay 80, opening contacts 80<SP>1</SP>, de-energizing timing relay 82. The solenoid 48 remains energized. (iv) After an interval sufficient for the trailing edge of the sheet S to pass the centre line of contact roller 18 contacts 82<SP>1</SP> open, de-energizing solenoid 48 returning billy roll 20 to the full line position. Operation (multiple pass).-Control switch 64 is placed in its other position with contacts a closed and contacts b open. The " forward " contacts 86 of a motor starter for the roll sets 12, 14 being closed, the cycle for the forward pass of the sheet S is as described above. After the forward pass, the " reverse" contacts 88 of the motor starter close, and the following cycle ensues. (i) The beam B<SP>1</SP> being interrupted by the sheet, unit 56 closes contacts 66, energizing timing relay 90 and in turn relay 94. Solenoid 48 is energized through contact 94<SP>1</SP>, whereby billy roll 20 is shifted to the right-hand dotted line position. (ii) After an interval sufficient for the leading edge of the sheet to reach the rolls 12, contact 94<SP>1</SP> opens, de-energizing solenoid 48, whereby billy roll 20 is shifted to the left-hand full line position where it remains to await the next forward stroke. If greater uniformity of grinding pressure is required to ensure absolutely uniform grinding depth, means may be provided so that the stroke of the billy roll is slightly arcuate. The billy roll transfer means may be operated hydraulically, electrically or mechanically. A high speed rotary drum may be used as the abrading member.