US 3168918 A
Abstract available in
Claims available in
Description (OCR text may contain errors)
Feb. 9, 1965 K. G. SMITH 3,168,918
CRIMPING MACHINE Filed June 1, 1962 IN VEN TOR:
Ke/ vi 6 ora'on 8m 17/7 ATT0RNEY United States Patent ()fiice 3,168,918 Patented Feb. 9, 1965 3,163,918 CRIMPIYG MACHINE Kelvin Gordon Smith, Strettord, England, assignor to Associated Electrical industries Limited, London, England, a British company Filed June 1, 1962, Ser. No. 199,370 Claims priority, application Great Britain, June 8, 1961, 20,765/ 61 3 Claims. (Cl. 153-11) This invention relates to crimping and has in view a power-operated crimping machine eminently suitable for crimping terminals on to electric cables.
Thepresent invention provides a power-operated crimping machine, such as for crimping terminals on to electric cables, comprising a hydraulically-operable ram and cooperating die or anvil having respective cooperating parts thereof shaped in accordance with the configuration to be applied by crimpage to a cable terminal or other assembly introduced between the ram and anvil, and pump means for applying hydraulic pressure of a high order to said ram in the closed condition of solenoid-operat'ed hydraulic valve means which can be opened at the end of a crimping operation to release said hydraulic pressure.
The pump means is preferably motor driven and may comprise a swashplate type pump or other pump having a fixed or adjustable constant stroke capable of providing hydraulic pressures of the order of 10,000 lbs. per square inch.
The maximum hydraulic pressure required for crimping may be pre-set preferably by suitable adjustment of a pressure-responsive switch connected in the hydraulic pressure system and effective upon the pressure reaching the pre-set value to bring about the opening of the solenoid-operated hydraulic valve means.
The crimping machine according to the invention in one exemplary form thereof comprises an electrical control circuit in which the energizing coil of a normally open solenoid operated hydraulic valve is connected to an alternating current supply via a control switch (e.g. foot operated) having normally open contacts.
By way of example one embodiment of the present invention will now be described with reference to the accompanying drawing, in which:
FIG. 1 is a schematic diagram of a power-operated crimping machine; and
FIG. 2 is a diagram showing in detail the electrical control circuit of the machine illustrated in FIG. 1.
Referring to FIG. 1 of the drawing, the crimping machine comprises a constant stroke oil pump 1, driven continuously by an electric motor 2 supplied with current through a starter 3 and an isolator 4 from a threephase supply 31. The oil pump 1 includes a rotary valve 5 arranged to be actuated from the open position, as illustrated, to a closed position by the energization of a solenoid 6 and the consequent rotation of a valve spindle 7 imparted through a linkage 8. The rotary valve 5 is connected in a hydraulic pressure system including a pipeline 9 extending to a ram 10 movable in a cylinder 11. The ram 11} co-operates with a die or. anvil 12 and the co-operating surfaces of the ram and die are shaped according to the configuration to be applied by crimpage to a cable terminal assembly for example introduced between the ram and anvil.
The pipeline 9 includes an adjustable pressure-responsive changeover switch 13, the moving contact 14 of which is displaced counter-clockwise as viewed in the drawing from its normal position as hydraulic pressure builds up in the pipeline 9. The solenoid 6 and an electromagneticrelay unit 10', the function of which will be described later are arranged to be supplied with current from a single-phase current supply SP under the control of the pressure-responsive changeover switch 13 and a foot-operated control switch (FIG. 2) having normallyopen contacts 15.
Referring now to FIGS. 1 and 2 of the drawing, it will be seen that the relay unit 10 has an energizing winding 16 with a pair of normally-open contacts 17 and 18 and that neither the relay 10 nor the solenoid 6 for actuating the rotary valve 5 to its closed condition will be energized. The valve 5 being open prevents the build up of hydraulic pressure in the pipeline 9 by the continuously operating constant stroke pump 1, while the moving contact 14 of the pressure-responsive switch 13 is making contact with a non-adjustable fixed contact of the switch 13 signifying zero hydraulic pressure.
A cable-terminal assembly (not shown) to be crimped is positioned on the die or anvil 12 of the crimping machine and the foot-operated control switch is then operated so that contacts 15 close. The operation of the control switch completes an energizing circuit through closed contacts 15 for the relay unit 10' which, in operating, causes the solenoid 6 to be energized over closed contacts 17. The solenoid 6, in operating, eliects closure of the hydraulic valve 5 to allow the hydraulic pressure to build up. The energizing circuit for the relay unit 10' includes a load resistor 19 as well as the co-operating moving contact 14 and non-adjustable fixed contact of the pressure-responsive switch 13 and the relay It), in operating, completes its own holding circuit by the closure of normally-open contact 18. Thus the relay 10 will be maintained in its energized condition and hence maintain the valve 5 closed upon the interruption of the initial energizing path for the relay 10 (i.e. through the contacts of the pressure-responsive. switch 13) as the hydraulic pressure builds up and the moving contact 14 of the pressure-responsive switch 13 disengages the nonadjustable fixed contact. g
The hydraulic pressure increases, forcing the ram 10 downwards 'into engagement with the cableterminal assembly positioned on the anvil 12, while the moving contact 14 of the pressure-responsive switch 13moves towards the adjustable fixedcontact of the switch which will have been pre-set to provide the desired maximum hydraulic pressure. At the pre-set hydraulic pressure which may be 10,000 lbs. per square inch, the moving contact 14 of the pressure-responsive switch engages with the adjustable fixed contact and by so doing the relay unit 10' releases due to the short-circuiting of its energizing winding 16 and consequently the energizing circuit of the solenoid 6 is interrupted by the opening of relay contacts 17 to bring about the opening of the valve 5 and the consequent release of the hydraulic pressure exerted on the ram 10. The ram 10 under the action of a return spring (not shown) accordingly disengages with the crimped cable-terminal assembly which can then be withdrawn from the anvil 12.
If the hydraulic pressure fails to reach the maximum pre-set value, such as may be occasioned for example by the failure of the pump 1, so that the moving contact 14 of the pressure-responsive switch 13 fails to make contact with the adjustable. pre-set fixed contact and short-circuit the relay coil 16, the hydraulic pressure can be released to enable the cable-terminal assembly to be removed from the machine by disconnecting the supply SP (FIG. 2) by switching means (not shown) so that the solenoid 6 is deenergizedand the hydraulic valve 5 opens.
If an operator Wishes to stop the crimping machine atv any time during the crimping operation, he can operate a push button switch 20 (FIG; 1) to open the motor cirremains. Normally the switch 20 locks out and cannot be restored to its closed condition without the use of a key,
which for proper supervision,may be retained by a supervisor. By this arrangement, an operator will be forced to disclose'the emergency to the supervisor.
A magnetic safety switch having normally-closed contacts 21 in series with the contacts 20 may also be providedand fitted to a personnel safety guard around. the ram and anvil assembly so that motor 2 cannot operate unless the guard is effective.
The crimping stroke of the ram is set and maintained by the engagement of abutments on the cooperating parts of .the ram 10 and anvil 12 when the hydraulic pressure reaches a valve lower than the pre-set value, thus providing a safety pressure margin preventing any possibility of bursting the cable-terminal assembly during crimpage.
To avoid damage to the machine in the event of excessive hydraulic pressures being built up, a spring-loaded safety value (not shown) may be connected in the hydraulic system.
What I claim is:
1. A power-operated crimping machine comprising a hydraulic ram, a die co-operating with said ram, surfaces on said ram and said die being shaped according to the configuration to be applied by crimpage to an assembly introduced between said ram and die, continuously operating pump means, driving means for said pump, a hydraulic pressure system, said pump means applying hydraulic pressure to said ram through said system, hydraulic valve means for controlling the hydraulic pressure introduced into said system, solenoid means for actuating said hydraulic valve means, a source of energizing current for said solenoid means, manually operated switching means controlling flow of said current to the solenoid means, adjustable switching means operable at the end of a crimping operation to efiect a change in the condition of'the solenoid means and thus the hydraulic valve means so as torelease the hydraulic pressure on said ram, said adjustable switching means being adjustable so that it operates when the maximum permitted hydraulic pressure is being applied to the ram.
2. A power-operated crimping machine comprising a hydraulic ram, a die co-operating with said ram, surfaces on said-ram and said die being shaped according to the configuration to be applied by crimpage .to an assembly introduced between said ram and die, continuously operating pump means, driving means for said pump, a hydraulic pressure system, said pump means applying hydraulic pressure to said ram through said system, hydraulic valve means controlling the hydraulic pressure introduced into said system, solenoid means for actuating said hydraulic valve means, manually operated switching means initially controlling flow of said current to the solenoid means, a holding circuit energized by closing of the manually operated switching means for maintaining energization of the solenoid means, a source of energizing current for said solenoid means and adjustable switching means operable at the end of a crimping operation to effect a change in the condition of the holding circuit and thus the hydraulic valve means so as to release the hydraulic pressure on said ram, said adjustable switching means'being connected in the hydraulic pressure system and being responsive to a maximum hydraulic pressure in said system to bring about the opening of the hydraulic valve means.
3. A power-operated crimping machine comprising a hydraulic ram, a die co-operating with said ram, surfaces on said ram and said die being shaped according to the configuration to be applied by crimpage to an assembly introduced between said ram and die, continuously-operating pump means, driving means for said pump, a hydraulic pressure system including said pump means, said pump means being capable of-applying hydraulic pressure to said ram through said system, hydraulic valve means in said system for controlling the hydraulic pressure, solenoid means for actuating said hydraulic valve means, an electric relay for controlling the energization of said solenoid means, a source of energizing current for the solenoid means and said relay, said relay being arranged for response at the end of a crimping operation to effect a change in the condition of the solenoid means and thus the hydraulic valve means, whereby to release the hydraulic pressure on said ram.
References Cited by the Examiner UNITED STATES PATENTS CHARLES W. LANHAM, Primary Examiner.