GB997231A - Belt grinding machine - Google Patents

Abstract

997,231. Grinding. K. HEESEMANN. July 5, 1961 [Oct. 22, 1960], No. 24280/61. Heading B3D. A belt grinding machine comprises an endless grinding belt and a pressure beam arranged to bring a desired width of the belt into grinding engagement with a workpiece being moved through the machine in a direction transversely of the direction of movement of the belt, the width of the belt to be brought into contact with the workpiece being steplessly adjustable to any width within limits by adjustment, in a direction normal to the working plane of the belt, of supporting elements for a flexible pressure plate acting on the belt, by means of a shifting device movable normal to the direction of movement of the supporting elements. An endless grinding belt 37 runs transversely of the direction of movement of a workpiece 10 through the machine. A pressure beam arranged between the runs of the belt has a box-like main structure 1 below which extends an elastic tube 2 of rubber or synthetic plastic filled with air or other medium. Below the tube 2 is a plate 3 of hardened spring steel or other flexible material extending over the whole length and width of the structure 1 and held by strips 4 of elastic material, e.g. rubberized linen, secured to the sides of the structure 1 by clamping members 5, 5a. A web 6, e.g. of felt, on the underside of the plate 3 exerts pressure on the grinding belt 37 through the intermediary of a steel plate 7 secured at the ends of the structure 1 in supports 8, 9. The pressure may be exerted directly or with the interposition of a laminated pressure belt. The flexible plate 3 is suspended on pairs of vertical bolts 14 arranged at both sides of the structure 1. Each bolt 14 is pivotally connected at its upper end to a lever 16. The levers 16 are connected in pairs by shafts 15. One lever of each pair carries at its free end a roller 19 or other follower for co-operation with an inclined surface 18 on a slide 17. The slide 17 has a handle 17b for shifting it along a guide rail 17a. When the workpiece is of a width corresponding to the full width of the pressure beam, the slide 17 is in the extreme right-hand position, Fig. 1, the levers 16 are in their lowermost positions and the plate 3 extends in a single plane so that a uniform grinding pressure is exerted by the belt over the whole width of the workpiece. For a narrower workpiece, as shown, the pressure beam is rendered ineffective from the region 12 to the region 13 by lifting a portion of the plate 3. This is done by moving the slide 17 to the left, so that the rollers 19 travel one after the other upwards on the inclined surface 18 of the slide, so raising the bolts 14. The inclined surface 18 is slightly longer than the levers 16 so that the roller 19 of the next pair of levers 16 is already on the inclined surface before the preceding roller 19 has left it. Shortly before a roller 19 has reached the highest point of the inclined surface, a pin 22 secured to the slide 17 abuts a pin 23 on a rocker arm 21 pivoted at 20 to a rail 20a, whereby the arm 21 is rocked counterclockwise to engage under a lug 16a on the lever 16 so locking the lever 16 in its upper position. The pin 23 comes to bear on the clamping member 5a so limiting the movement of the arm 21; the pin 22 is thus set free, permitting further movement of the slide to the left. On return movement of the slide 17 to the right, the pin 22 abuts a pin 24 on the arm 21 rocking the arm clockwise to release the lever 16 so allowing the roller 19 to run off the inclined surface 18. When setting up, the slide 17 is moved until the handle 17b is vertically above the right-hand end of the workpiece. To permit fine adjustment at the ends of the pressure beam when the slide 17 is not fully effective, bolts 25, 26 connected to the plate 3 near its left-hand end are connected to bellcrank levers 27, 28 fixed on a shaft 29 and adjusted by a spindle 30. Bolts 31, 32 connected to the plate 3 near its right-hand end are connected to bell-crank levers 33, 34 fixed on a shaft 35 and adjusted by a spindle 36. Instead of the slide 17, a chain with a cam secured thereto or a spindle with a nut thereon may be used, the inclined surface 18 being provided on the cam or nut.