Patent GB-1226968-A (GB)
IPC: B23D47/04
Filed: 1967-09-13
Abstract: 1,226,968. Sawing. J. HURN, C. R. F. KING, and D. R. DEANE. 5 Sept., 1968 [13 Sept., 1967], No. 41799/67. Heading B5L. [Also in Divisions B3 and B8] A method of positioning an elongate workpiece so that it may be worked, e.g. sawn, at any preselected point along its length, comprises passing the workpiece from a working tool such as a saw, on a longitudinal conveyer B, Fig. 2; selecting a stop 20 from a plurality of such stops spaced from the working tool over part of the length of the conveyer; adjusting the relative longitudinal position of the working tool and a common structure C carrying the stops, the distances between the stops being uniform; placing the selected stop in the path of the workpiece to arrest its further progress on the conveyer. The common structure is permitted to move under the control of pneumatic cushioning means 50 relative to the conveyer longitudinally over a limited distance on impact of the workpiece against a selected stop, and the pneumatic cushioning means reverse the common structure after it has so moved to reposition the selected stop a preselected distance from the working tool. In the machine described for performing the method the stops 20 are carried by a beam 12 and may be moved into the path of a workpiece on a belt, as shown, or roller conveyer 10 by pneumatic rams. The longitudinal position of the beam 12 relative to a datum position X at which the working tool acts is controlled by rotation of a lead-screw 40 coupled to the beam 12 by the pneumatic cushioning device 50. The working tool is a circular saw 101, Figs. 2 and 8, which is slidable vertically and can also be moved about a vertical axis through the position X to alter the angle at which a workpiece is cut, e.g. to form a mitre. In operation of the machine the selected stop 20, Fig. 2, is moved to its operative position by its pneumatic ram, and the lead-screw 40 is rotated via a gear-box 42 to locate the stop 20 in the desired position. The angle of the saw is also adjusted. When a workpiece enters the apparatus sensing devices cause rollers 131, 132, Fig. 8, to be lowered and in co-operation with driven rollers 121, 122 to advance the workpiece on to the belt 10. The workpiece then abuts the operative stop 20 and the impact shock is absorbed by retraction of a piston of the device 50. Such retraction operates a switch to cause disconnection of the drive to rollers 121, 122 and the raising of rollers 131, 132. The pressure within a cylinder of the device 50 then causes its piston to advance to return the workpiece to the preselected position and to operate a further switch. This causes interruption of the drive of belt 10 and the operation of pneumatic devices 145, Fig. 2, and 140, Fig. 8, which clamp the workpiece against a fence 150 and idle rollers 128, respectively. The saw is then lowered to cut the workpiece and then raised. Meanwhile the stops 20 and the lead-screw 40 may be positioned in readiness for the next workpiece. The devices 140, 145 are then released, the drive to rollers 122, 121 reconnected, the belt drive resumed, and the cut workpiece ejected. The offcut may also be fed through the apparatus, or fall, or be removed by a sweep arm.