Patent GB-463312-A (GB)
Title: Improvements relating to sawing machines and like metal or other cutting machine tools
IPC: B23D47/04
Filed: 1935-09-19
Abstract: 463,312. Hydraulically-operated sawing and like machines. RUSSELL, W. S., and HILL, D. M. J. Sept. 19, 1935, No. 25973. [Class 145 (ii)] Sawing-machines and like metal or other cutting - machine tools are provided with hydraulically operated means for producing relative movement between the cutting tool and the work piece during each cutting operation and with a reciprocatory work gripper which is adapted to grip and then feed forward the work piece under hydraulic pressure after each cutting operation and with a reciprocatory work gripper which is adapted to grip and then feed forward the work piece under hydraulic pressure after each cutting operation in combination with valve mechanism for automatically controlling the supply of pressure fluid to the said means and to the gripper. A hydraulically operated stationary gripper is provided for holding the work piece during the cutting operation, the means for controlling the supply of pressure fluid for actuating the stationary and reciprocatory grippers including valve mechanism responsive to the pressure of the fluid which moves the cutting tool relatively to the work piece during the cutting operation. The means for controlling the supply of pressure fluid for producing the relative movements which take place between the work piece and the cutting tool during the cutting operation includes valve mechanism which, when the reciprocatory gripper has completed its forward stroke, is acted upon the pressure fluid which effected the said stroke. A valve is provided which is responsive to the action of the mechanism for producing reciprocation of the cutting tool and is adapted to prevent feeding movement of the work piece by the reciprocatory gripper until the cutting tool occupies a predetermined position. A circular saw metal cutting machine comprises a stationary gripper having jaws a, b actuated by piston and cylinder arrangements c, d and e, f ; the jaws a, b are capable of initial adjustment relatively to the hydraulically actuated parts carrying them by means of serews g ; the position of the gripper on the bed h can be adjusted. The reciprocatory gripper comprises jaws i, j hydraulically actuated by piston and cylinder arrangements l, m and carried by a slide k reciprocated hydraulically by the piston and cylinder p, o. The saw q is carried by a slide reciprocated hydraulically by the piston and cylinder s, r. One end of the cylinder r is connected to a constant delivery pump t and the other end of the cylinder r is connected to a variable delivery pump u through a valve-box x containing a valve v controlling the supply to the cylinder and a valve w controlling the return pipe 4 to the reservoir 15 ; a relief valve 2 having a return pipe 3 to the reservoir is associated with the valve v. The pumps u, t are driven by an electric motor. This arrangement is described in Specification 418,013, [Group XXIX]. The valves v, ware closed by springs and opened by cams 5 on a shaft having a handle 6. Pressure fluid for actuating the stationary and reciprocatory grippers is supplied by the constant delivery pump t through a valve 9 which is moved in one direction by a spring 10, and in the other direction by fluid supplied by the auxiliary valve 11. The cycle of operations is as follows. At the end of the working stroke of the saw, the valves v, w are opened, either by the saw slide acting on the spindle of the cams 5 or by manipulation of the handle 6 ; the constant delivery pump t now effects a rapid return of the saw slide, at the end of which the valve v is closed by the saw slide, the valve w remaining partially open. The valve 9 is forced to the right by the spring 10, the right-hand side of the valve communicating with the reservoir through the chamber of the valve 11. Pressure fluid from the constant delivery pump t is thus admitted to the cylinders m to close the jaws i, j of the reciprocatory gripper on to the work against the action of springs, and to the cylinders d, f to retract the jaws a, b of the stationary gripper from the work. The piston e moves freely, since its exhaust side is connected to the reservoir through the open valve w, but the motion of piston c is retarded by a check valve 16 in the exhaust side of cylinder d ; the work is thus clamped by the jaws of the reciprocatory gripper before it is released by the jaws of the stationary gripper. On the completion of these movements, the pressure of fluid rises and opens a spring-loaded valve 17 which admits fluid to the cylinder p to feed the reciprocatory gripper and work forward by an amount determined by adjustable stops. At the completion of this feed movement, the further rise in pressure opens the spring-loaded valve 19 and admits fluid to a cylinder 21 containing a piston 22 which is moved to close the exhaust valve w. The pressure in the box x now rises and the variable delivery pump u supplies fluid to the cylinder f to close the jaw b of the stationary gripper on to the work ; at the same time or immediately afterwards, the pressure fluid from the variable delivery pump u opens the valve 11 against its spring and moves the piston valve 9 to the left ; the outer ends of the cylinders m are thus put to exhaust, and the jaws i, j of the reciprocatory gripper retracted by springs from the work. Pressure fluid from the constant delivery pump t closes the jaw a of the stationary gripper on to the work ; on completion of this movement, the pressure rises and opens a spring- loaded valve 25 to admit fluid to the cylinder p to retract the reciprocatory gripper to its starting position. The pressure in the box x also opens the valve v against its spring to admit fluid from the variable delivery pump n into the cylinder r to perform the working stroke of the saw, thus completing the cycle. To prevent feeding of the work forward until the saw has been retracted clear of it, the feeding end of the cylinder p is connected through a valve 30 to the reservoir ; the valve 30 is normally closed by a spring 31, but is opened by a lever 29 actuated by a dog 28 on the saw slide when the latter is in a forward position. A valve 32 is provided between the stationary gripper and the reciprocatory gripper to enable the latter to be put out of action when automatic feeding is not required. Specification 452,317 also is referred to.