Motorized weld head
First Claim
1. A method of contacting an object by an electrode with user-controlled parameters comprising:
- (a) providing a movable electrode;
(b) generating a speed control signal defining a rate of motion of the electrode;
(c) generating a force control signal defining a force to be placed on the object by the electrode;
(d) generating a position control signal defining a displacement of the electrode relative to the object;
(e) generating a duration control signal defining a length of time the electrode contacts the object;
(f) integrating the speed, force, position, and duration signals in a control means;
(g) driving the electrode toward a position proximate the surface of the object by the control means at the rate of motion defined by the speed control signal; and
thereafter(h) further driving the electrode toward the object at a rate of motion less than the rate of motion defined by the speed control signal.
5 Assignments
0 Petitions
Accused Products
Abstract
The motorized weld head employs a control system which allows user control of critical welding parameters such as speed, force, position, and duration. The control system includes a position servo loop attached to a motor-driven output shaft on which a welding electrode is mounted via a spring. During a weld cycle, the control system moves the welding electrode toward a workpiece at a rapid user-defined rate. Just prior to when the electrode contacts the workpiece, the speed of the electrode is reduced to prevent damage to the parts. When contact is made, a pressure transducer measures the force exerted by the electrode on the workpiece. A comparator continuously monitors the force measured by the transducer and changes state when the measured force equals a user-defined optimum welding force. A signal is then passed to the servo loop commanding it to hold the position of the electrode effectively maintaining the applied force on the workpiece. When mechanical vibrations diminish, a user-defined weld current is enabled to the electrode. After the weld current is fired, the constant force is maintained until the weld cools. Finally, the welding electrode is automatically raised by the control system, releasing all pressure on the workpiece.
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Citations
22 Claims
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1. A method of contacting an object by an electrode with user-controlled parameters comprising:
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(a) providing a movable electrode; (b) generating a speed control signal defining a rate of motion of the electrode; (c) generating a force control signal defining a force to be placed on the object by the electrode; (d) generating a position control signal defining a displacement of the electrode relative to the object; (e) generating a duration control signal defining a length of time the electrode contacts the object; (f) integrating the speed, force, position, and duration signals in a control means; (g) driving the electrode toward a position proximate the surface of the object by the control means at the rate of motion defined by the speed control signal; and
thereafter(h) further driving the electrode toward the object at a rate of motion less than the rate of motion defined by the speed control signal. - View Dependent Claims (2, 3, 4)
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5. A motorized weld head comprising:
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means for selecting a speed control signal representative of the speed of an electrode relative to an object; means for selecting a force control signal representative of a force to be applied by the electrode on the object; position monitoring means for continuously monitoring position of the electrode relative to the object; means coupled to the position monitoring means for moving the electrode at the speed represented by the speed control signal; force monitoring the means for monitoring the force applied by the electrode to the object; means for comparing the monitored force to the selected force; and means for maintaining the selected force exerted by the electrode on the object for a predetermined time. - View Dependent Claims (6, 7, 8, 9, 10)
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11. A motorized weld head comprising:
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a support means; means for mounting a movable shaft on the support means permitting motion of the shaft relative to the support means; driving means for moving the shaft linearly with respect to the support means; speed control means for controlling a rate at which the shaft moves linearly with respect to the support means; spring means for resiliently attaching a welding electrode to the movable shaft; operator controlled means for controlling a force to be exerted by the weld head; means for measuring a force exerted on a workpiece by the electrode; means for comparing the operator controlled force to the measured force; and means for maintaining the operator controlled force between the electrode and the workpiece for a predetermined duration. - View Dependent Claims (12, 13, 14, 15, 16, 17)
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- 18. A motorized weld head comprising the combination of control system having speed control means attached to motor means, driving means attached to the motor means, force sensing means attached to the driving means, spring means attached to the force sensing means, and welding means attached to the spring means.
Specification