GB1484851A - Abrading machine - Google Patents

Abstract

1484851 Abrading P ERNST 6 Jan 1976 [24 Jan 1975 2 Oct 1975] 00285/76 Heading B3D An abrading machine comprises a workpiece conveying mechanism 3, spaced reels 14, 17 from one of which an abrading belt or web 18 runs alternately to the other and back again, a contact element 10 for pressing the belt or web between the reels against the workpiece 19 when the latter is conveyed by the mechanism 3, the contact element or means 24, 25 associated therewith being driven to move the belt or web at a substantially constant speed between the reels, and respective drive means for each reel operable to rotate the reel receiving belt or web at a speed responsive to the diameter of the web or reel thereon and on the speed of travel of the belt or web and to brake the reel from which the belt or web is being unwound. The conveying mechanism consists of a belt 3 on guide rollers 2 which are mounted on a frame 1 and driven by a chain 6 and motor 5 to carry the workpiece 19 below a roller 9 having a covering 10 which comprises the contact element, the roller being driven by gearing 21 from a motor 22. The roller is supported by bearings 11 in a U-shaped frame 8 which is vertically adjustable by adjusting means 7 to accommodate workpieces of different thickness. The uprights of the frame 8 carry respective winding reels 14, 17 driven by motors 12, 15 and chain drives 13, 16 so that the abrading belt is wound off reel 14 over the roller 9 and on to the reel 17 and vice-versa to abrade the workpiece which is pressed against the conveyer belt 3 by pressure rollers 20. The motors 12, 15 are controlled so that the wind-up speed of the abrading belt is constant. In another embodiment, the contact element is in the form of a beam (26, Fig. 3, not shown) having rollers (24) on each-side. Each motor 12, 15, Fig. 10, has a shaft 65 at one end having a turbo-clutch 63 and toothed wheel 64 for driving its reel, and, at the other end, having a freewheel clutch 66, the outer ring of which is held stationary by a retaining means 67. During winding up, the shaft 65 can turn freely in the clutch 66 and the torque transmitted corresponds to the diameter of the winding and takes place through the turbo-clutch 63. During winding off, the shaft 65 is held and the braking moment is applied by the turbo-clutch. Each reel 14, 17 consists of a tube 54, Fig. 8, having longitudinal slots 62 and housing a rubber hose which is inflatable through a valve 60 to expand the tube to grip the abrading belt. The reel 14, 17, or both reels, may be mounted on a carriage 28, Fig. 4, supported by rollers 29 for axial movement to control the tracking of the abrading belt, the movement of the carriage, and hence the reel, being effected by a motor 27 driven in one direction or the other under the control of a roller 37 which engages the edge of the belt 18 and is carried by a cranked lever 38, 39 engageable, when the edge of the belt deviates from its proper path, with one or other of contacts 41, 42, the motor being connected by gearing 33 to a screw 34 engaging a nut 32 fixed to the carriage 28.