Patent GB-1068141-A (GB)
Title: Gang sawmill with particular hydraulic saw blade tensioning means
IPC: B27B3/34
Filed: 1966-01-17
Abstract: 1,068,141. Sawing. SUPER-CUT Inc. Jan. 17, 1966 [March 18. 1965], No. 2144/66. Heading B5L. A gang sawmill comprises a substantially rectangular sash 26 mounted for back and forth movement and having a header beam 54 and a foot beam 56, a plurality of parallel spaced apart saw blades 80 disposed within the sash and at right angles to the beams with their rear ends connected to the foot beam, connecting devices individual to the front ends of the blades and operative to connect them to the header beam, each device including a separate hydraulic tensioning unit 100 embodying a socket and plunger adapted, when supplied with fluid under pressure, to project the socket and effect tensioning of the blade, means for regularly and simultaneously supplying fluid under pressure from a common source 142 to all the sockets to effect uniform tensioning of the blades, and means to move the sash back and forth. As described, the sawmill is used to cut a ceramic block B into a number of slabs S 1 , S 2 , the block being mounted on a carriage 32 having flanged wheels 36 running on rails 38, and the carriage being held stationary during a sawing operation by means of wedges 40 and struts 42. The rails are disposed between a pair of side supports consisting of masonry walls 30 on which are structural members including a horizontal channel 24 serving as a guide for the back and forth movement of the sash 26. Vertical feed screws 50 driven from a common shaft 51 are adapted to raise and lower the sash. The header and foot beams 54, 56 of the sash are interconnected by side rails 66 and each beam is split into upper and lower parts 58, 60, 62, 64 defining therebetween slots 61. The ends 68 of the beams project into the channels 24 to provide slides for guiding the back and forth movement of the sash which is effected by a poweroperated driver connected to a rod 70. The ends of the blades 80 have wedges 82, Fig. 5 (not shown) gripped by hangers 84, the wedges and hangers engaging along arcuate regions. The rear hangers are pivotally connected to links 90 which extend through the slot between the parts 62, 64 of the foot beam and are formed with heads engaging the outer surface of the parts. The front hangers 84 are connected by pivots 92 to links 94 which extend through the slot 61 in the header beam 54 and are formed on their outer ends with structures 96 provided with vertical slots 102 through which the tensioning units 100 extend. Each unit 100 has a thin portion 106 (Fig. 12, not shown), which passes through the slot and is formed with a curved part 108 engageable with a tension adjusting screw 110 and a toe 112 which abuts the front face of the lower part 60 of the header beam 26. A thick portion 104 of each unit 100 contains three cylinders 120, Fig. 4 (not shown), having plungers 122 abutting the upper part 58 of the header beam. The cylinders 120 are connected by a manifold 124 to a nipple 128 and all the nipples are connected by pipes 164 to a tubular manifold 140 which is connected to an accumulator 146 and a hand pump 142. When fluid under pressure is supplied to the cylinders 120, the plungers press against the face of the upper part 58 of the beam to rock the units about the toes 112 so that the curved parts 108 press against the screws 110 in the structures 96 to apply tension to the blades. Shoulders 101, Fig. 4 (not shown) limit the movement of the structures so that, if a saw blade is not connected to a hanger, the unit may still remain in the installation. The units 100 permit a minimum spacing between the blades for cutting thin slabs S 1 . When thicker slabs S 2  are to be cut, the units 100 are replaced by units 200, Fig. 13 (not shown), which have cylinders and plungers 212 both above and below the part 206 for engaging the slot in the structure 96. In another embodiment, Figs. 14 and 15 (not shown), the header beam 300 is solid and the saws 80 are connected to hangers 312 having parts 306, 314 extending above and below the beam and connected to structure 326, tensioning units 334 having cylinders and plungers 330 being disposed in slots in the parts 306, 314 with the plungers engaging the beam.