Patent GB-738878-A (GB)
Title: Means for transferring work pieces to or from a cutting or shaping press
IPC: B21D43/10
Filed: 1953-05-21
Abstract: 738,878. Metal sheet feeds. UDAL, J. D. Jan. 19, 1954 [May 21, 1953], No. 14275/53. Class 83 (4). Means for transferring workpieces to or from a cutting or shaping press comprises the combination of an oscillatory arm constructed substantially similar to a parallel motion linkage, supporting means for attachment to the press the upper part of the arm being pivotally connected thereto and a workpiece carrier arranged at the lower end of the arm. The transfer arm consists of two pairs of links f, g, the upper ends of links f being adjustably and pivotally attached to brackets h secured to the press frame e and the upper ends of links g are freely attached to a spindle i supported by the brackets h. The lower ends of the links f, g are pivotally attached to horizontal links j interconnected by transverse rods k, m, the rod m carrying a workpiece carrier p which is retained on a horizontal position by engagement of rollers q with the links j. The carrier is tipped when the transfer arm is swung away from the press by means of a chain z. A pair of sectors s are secured to the shaft i and the links g are adjustably secured thereto. Actuation of the transfer arm is effected by links v connected to the sectors s and to the slide d of the press. In a modification the upper end of an adjustable link f<SP>1</SP> is freely mounted on a spindle 3 and the upper end of the link g<SP>1</SP> is adjustably secured to a spindle i<SP>1</SP>. The link f<SP>1</SP> consists of spring-loaded slidable parts 4, 6 which enables the link to be extended by a cam 4 on the spindle 3 to impart pivotal movement of the arcuate link j<SP>1</SP> about its connection with the link g<SP>1</SP>. A carrier is supported on the arcuate link j<SP>1</SP> and an adjacent similar link 11 and comprises a pair of pivoted grippers 12 actuated by a wedge 16 engaging spring-loaded gripper arms 15. The wedge is actuated by a spring-loaded pneumatic piston 19. Actuation of the transfer arm is effected from a rotary shaft 23 through a crank-pin 24 and a spring-loaded extensible link 25 connected to a radial arm 26 on the spindle i<SP>1</SP>. Stops 28 which are engaged by a radial arm 29 ensure the required dwell between successive movements of the transfer arm. The shaft also serves to drive the spindle 3. A cam 33 on the shaft 23 actuates a spring- loaded valve 34 controlling the compressed air flow to the gripper piston 19 and also a valve 35 which controls the intermittent rotation of a table 36 carrying workpieces which are fed by the grippers 12 to the stationary tool a<SP>1</SP> of the press. In a further modification for removing workpieces from a press each extensible link f<SP>2</SP> of the transfer arm consists of slidable parts 5<SP>2</SP>, 6<SP>2</SP> interconnected by pneumatically operable means comprising a spring-loaded piston 40 adjustably secured to the part 6<SP>2</SP> and a cylinder 41 adjustably secured to the part 5<SP>2</SP>. A carrier is mounted on the rod m<SP>2</SP> and comprises a body 44 and a pair of grippers 45, 46. The pivoted gripper 46 is connected to a spring-loaded pneumatic piston 49. Actuation of the transfer arm is effected from a rotary shaft 232 carrying a crank 24<SP>2</SP> connected to a radial arm 26<SP>2</SP> on the spindle i<SP>2</SP>. An adjustable stop 282 on the bracket h<SP>2</SP> limits the inward swing of the transfer arm by engaging a radial arm 29<SP>2</SP> on the spindle i<SP>2</SP>. Cams 53, 54 on the spindle i<SP>2</SP> actuate pivoted members 55, 56 of spring- loaded valves 57, 58 controlling the gripper piston 49 and the pistons 40 for lengthening the links f<SP>2</SP> respectively. The lengthening of the links f<SP>2</SP> pivots the links j<SP>2</SP> about their connections with the links g<SP>2</SP> and causes the grippers to raise the workpiece c<SP>2</SP> clear of the stationary tool a<SP>2</SP> of the press. At the end of the outward swing of the transfer arm the valve 58 is actuated to release air pressure from the pistons 49 and 40 and the grippers release the workpiece. Alternatively, the transfer arm may be operated by fluid pressure or electromagnetic means or by an electric motor independently of the moving parts of the press.