Patent GB-673017-A (GB)
Title: Improvements in or relating to control elements for riveting systems
IPC: B21J15/20
Filed: 1949-12-08
Abstract: 673,017. Riveting-machines. CHICAGO PNEUMATIC TOOL CO. Dec. 8, 1949 [June 16, 1949], No. 31537/49. Class 83 (iv). [Also in Group XXIX] A fluid-operated riveting-machine has a number of tool heads, the supply of fluid pressure being controlled by electrically-operated valves and switches so that only one head at a time can be in operation. The machine comprises a low-pressure pump 21b, Fig. 9, driven by an electric motor 21a, a pressure booster 21d, and an electrically-controlled distributing valve 21e which controls one toolhead C directly and two other heads A, B through a manually-operated valve 20. In operation, a switch 24 is manually closed to start motor 21a, the pump 21b delivering part of its output by pipes 23 (a, b, c) to the lowpressure sides of the tool cylinders to withdraw all three plungers, the high-pressure sides of the plungers being connected to the reservoir 21c by pipes 22 (a, b, c), and the pump also supplying fluid to solenoid-controlled valves 21 (f<1>, f<2>). If switch 80 on head C is now closed manually, valve 21f<2> directs fluid to valve 21e to allow fluid to flow from booster 21d to head C by pipe 22c, the booster not functioning at this stage to raise the pressure. When the tool engages the work, however, an automatic valve causes the booster to increase the pressure for the working stroke, and when the rivet is set, further automatic rise in pressure actuates a pressure - controlled switch 21h to restore solenoid-valve 21f<2> to its initial condition. The booster 21d then ceases to raise the pressure and fluid proceeds from pump 21b by pipe 23c to the head to withdraw the plunger, fluid from the high-pressure side of the head flowing to the reservoir through pipe 22c and the distributer valve 21e. Head C may be caused to repeat the riveting cycle by again depressing switch 80c, or head A or B may be operated, to the exclusion of the others. To operate head A, a hand lever 70 is actuated to set a rotary valve in casing 20 in position to connect the high-pressure side of the head by pipe 22a to distributer valve 21e ready for a working stroke. A switch in casing 20 is connected to the rotary valve and is simultaneously engaged to close a circuit from switch 80a and leads 68a so that manual depression of the switch will energize solenoid valve 21f<1> to admit fluid to distributer valve 21e, this connecting the fluid supply from the booster to valve 20 so that the plunger in head A will commence its working stroke and the booster will then function to supply fluid at working pressure. When the rivet is set, the plunger is returned as described for head C. For operating head B, hand lever 70 is set to connect this head by pipe 22b to distributer valve 20 and close the circuit to manual switch 80b, these settings severing the controls to head A. Valves. The valve 20 consists of a chamber 36, Figs. 3 and 4, in communication with the fluid supply line 43 and a rotary disc valve 30 actuated by a crank-pin 41 on a manuallyoperated shaft 27. The chamber 36 communicates by double ports 55, 56 with the supply lines 22a, 22b, respectively, which lead to the plungers of the riveting heads A, B, Fig. 9, whilst the interior 40 of the valve 30 communicates by port 49 and passages 44, 50 with the exhaust line 58 leading to the reservoir 21c. With the valve 30 in the position of Fig. 3, fluid passes from supply line 43 and pipe 22b to head B whilst the low-pressure side of head A is connected to reservoir by pipe 22a and the interior 40 of the valve, these connections being interchanged in the other position of the valve. A spring plunger 46 engages flats 48a, 48b, on the shaft 27 to locate the valve in either position. Cams 60a, 60b on shaft 27 engage the plungers of switches 59a, 59b in circuit with the manual switches 80a, 80b on the riveting heads A, B to break the circuit to the head which is cut off from the supply line 43. The shaft 27 is operated by a hand lever 70 which may have a remote control link 74. A spring 31 maintains valve 30 against its seat.