US3628330A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Speed-programmed friction welder control
Assignee: Caterpillar Inc
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Filing: 1970-03-16
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Granted: 1971-12-21
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Expires: 1990-03-16
Abstract
Abstract A drive in a speed-programmed friction welder can be controlled by an electronic loop employing circuits to continuously compare the actual speed of the drive with the programmed speed throughout the weld interval and adjusting the drive so the relative rotational speeds of the parts (workpieces) being welded will decrease to zero according to a prescribed programmed pattern. Since the necessary relative rotational speeds of the workpieces may vary when welding stock of different sizes or materials, and also the weld time interval may change, a control must provide independent control of both speeds and time during the weld cycle which are features of the instant invention.
Inventors
- 👤 Robert G Miller
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 05:38
CPC Classifications
G; G05; G05D; G05D13/00; B; B23; B23K; B23K20/00; B23K20/12; B23K20/121; Y; Y10; Y10S; Y10S60/00; Y10S60/911
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
135 words
A programmable control system for variable-speed drive means which include a hydrostatic transmission with a variable displacement hydraulic pump and a hydraulic motor comprising: circuit means prodUcing a changeable amplitude versus-time signal according to a preselected speed-time program; transducer means driven by said hydraulic motor and generating a speed signal proportional to the actual speed of said motor; logic circuit means connected to receive as inputs said amplitude-versus-time signal from said circuit means and said speed signal from said transducer means and operable to give an output error signal proportional to the difference between said input signals; and actuator means connected to said variable displacement hydraulic pump to change its displacement and also connected to receive said output error signal, said actuator means changing the displacement of said pump in response to said error signal.
Claim 2
Dependent Claim
135 words
A programmable control system for variable-speed drive means which include a hydrostatic transmission with a variable displacement hydraulic pump and a hydraulic motor comprising: circuit means prodUcing a changeable amplitude versus-time signal according to a preselected speed-time program; transducer means driven by said hydraulic motor and generating a speed signal proportional to the actual speed of said motor; logic circuit means connected to receive as inputs said amplitude-versus-time signal from said circuit means and said speed signal from said transducer means and operable to give an output error signal proportional to the difference between said input signals; and actuator means connected to said variable displacement hydraulic pump to change its displacement and also connected to receive said output error signal, said actuator means changing the displacement of said pump in response to said error signal.
Claim 3
Dependent Claim
67 words
The programmable control system as described in claim 1 wherein a dump valve is included between the hydraulic pump and motor and a comparator means is connected to the logic circuit means and said dump valve, whereby said dump valve will vent any fluid flow from said pump to said motor when said logic means require zero speed from said motor to avoid creep in said motor.
Claim 4
Dependent Claim
81 words
The programmable control system as described in claim 2 wherein both the hydraulic pump and the hydraulic motor are variable displacement units, a motor actuator means is connected to said variable displacement motor, said motor actuator means is connected to logic circuit means and said logic circuit means includes ''''OR'''' and ''''AND'''' gates whereby pump displacement will be varied for low-speed ranges and motor displacement will be decreased for higher speed ranges, with the uncontrolled unit always at its maximum displacement.
Claim 5
Dependent Claim
38 words
The programmable control circuit described in claim 2 wherein the circuit means includes a variable timing generator connected to a function generator whereby said logic circuit will receive a time-based variable amplitude signal representing the preselected speed-time program.
Claim 6
Dependent Claim
48 words
The programmable control circuit as described in claim 4 wherein the timing generator produces a linear increasing voltage proportional to the amplitude of its voltage input and the function generator includes means for generating a plurality of straight-line functions, the sum of which approximates the preselected speed-time program.
Claim 7
Dependent Claim
44 words
The programmable control circuit as described in claim 5 wherein the hydraulic motor is a variable displacement unit and includes actuating means connected to it for varying its displacement in response to an error signal from the logic circuit means above a predetermined amplitude.
Claim 8
Dependent Claim
55 words
The programmable control circuit as described in claim 5 wherein the timing generator includes a manual position in which the voltage amplitude of the time signal can be advanced manually and the function generator includes adjustable means to vary the length and slope of its straight-line functions whereby any selected speed-time profile can be fabricated.
Claim 9
Dependent Claim
18 words
The programmable control circuit as defined in claim 7 wherein the function generator is a diode function generator.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-12-20 | 1975-06-21 | 1975-12-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-12-20 | 1979-06-21 | 1979-12-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-12-20 | 1983-06-21 | 1983-12-21 | $7700.00 | Window Closed / Lapsed |