US3825912A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Torque wrench monitor
Assignee: Motors Liquidation Co
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Filing: 1973-07-12
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Granted: 1974-07-23
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Expires: 1993-07-12
Abstract
Abstract A circuit for providing an indication each time a threaded element has been properly tightened by a power torque wrench. A first switch is actuated upon the initiation of operation of the torque wrench to enable a capacitor to be charged at a predetermined rate. A second switch is responsive to the achievement of a predetermined torque output by the torque wrench to couple the charge across the first capacitor to the base of a transistor through a second capacitor. If the elapsed time between the actuation of the first switch and the actuation of the second switch is greater than a predetermined minimum, the signal coupled to the base electrode of the transistor is sufficient to bias the transistor into conduction to energize a lamp for providing an indication that the bolt has been properly tightened.
Inventors
- 👤 D Wiese
- 👤 R Sawicki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 13:25
CPC Classifications
B; B25; B25B; B25B23/00; B25B23/14; B25B23/145; B25B23/1456; B25B23/147; Y; Y10; Y10S; Y10S81/00; Y10S81/05
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
224 words
A circuit for providing an indication when a threaded element has been properly tightened by a power torque wrench comprising: first and second bistable switch means, each of said switch means being shiftable between respective first and second states; means responsive to the initiation of operation of the power torque wrench for shifting the first bistable switch means to its second state; a timing circuit coupled to the first switch means for generating an output voltage having a magnitude related to the elapsed time from the shifting of the first bistable switch means to its second state, the magnitude of the voltage being a set value after an elapsed time equal to a minimum time required for the power torque wrench to properly tighten the threaded element; means responsive to the achievement of a predetermined torque by the power torque wrench for shifting the second bistable switch means to its second state; indicating means; and means coupled to the timing circuit and the second bistable switch means for energizing the indicating means when the instantaneous magnitude of the output voltage when the second bistable switch means is shifted to its second state is equal to or greater than the set value, whereby the energization of the indicating means is an indication of the proper tightening of the threaded element by the power torque wrench.
Claim 2
Dependent Claim
224 words
A circuit for providing an indication when a threaded element has been properly tightened by a power torque wrench comprising: first and second bistable switch means, each of said switch means being shiftable between respective first and second states; means responsive to the initiation of operation of the power torque wrench for shifting the first bistable switch means to its second state; a timing circuit coupled to the first switch means for generating an output voltage having a magnitude related to the elapsed time from the shifting of the first bistable switch means to its second state, the magnitude of the voltage being a set value after an elapsed time equal to a minimum time required for the power torque wrench to properly tighten the threaded element; means responsive to the achievement of a predetermined torque by the power torque wrench for shifting the second bistable switch means to its second state; indicating means; and means coupled to the timing circuit and the second bistable switch means for energizing the indicating means when the instantaneous magnitude of the output voltage when the second bistable switch means is shifted to its second state is equal to or greater than the set value, whereby the energization of the indicating means is an indication of the proper tightening of the threaded element by the power torque wrench.
Claim 3
Dependent Claim
323 words
A circuit for providing an indication when a threaded element has been properly tightened by a power torque wrench comprising: a DC power source; a timing circuit coupled in parallel with the DC power source, the timing circuit including a resistor and a first capacitor coupled in series; a first normally closed switch means coupled in parallel with the first capacitor; means responsive to the initiation of operation of the power torque wrench for opening the first normally closed switch means to enable the first capacitor to be charged by the DC power source to a voltage having a magnitude related to the elapsed time from the opening of the first normally closed switch means, the magnitude of the voltage being a set value after an elapsed time equal to a minimum time required for the power torque wrench to properly tighten a threaded element; a second normally nonconducting switch means, the second normally nonconducting switch means being responsive to a voltage signal supplied thereto having a magnitude equal to or greater than a predetermined bias level for shifting to a conducting state; a second capacitor having one side coupled to the second normally nonconducting switch means; means responsive to the achievement of a predetermIned torque by the power torque wrench for applying the voltage charge on the first capacitor to the second side of the second capacitor to charge the second capacitor and supply a voltage pulse to the second normally nonconducting switch means, the voltage pulse having a magnitude equal to or greater than the predetermined bias level when the magnitude of the voltage on the first capacitor is equal to or greater than the set value; indicating means; and means responsive to the conduction of the second normally nonconducting switch means for coupling the indicating means in parallel with the DC power source to provide an indication of the proper tightening of the threaded element by the power torque wrench.
Claim 4
Dependent Claim
323 words
A circuit for providing an indication when a threaded element has been properly tightened by a power torque wrench comprising: a DC power source; a timing circuit coupled in parallel with the DC power source, the timing circuit including a resistor and a first capacitor coupled in series; a first normally closed switch means coupled in parallel with the first capacitor; means responsive to the initiation of operation of the power torque wrench for opening the first normally closed switch means to enable the first capacitor to be charged by the DC power source to a voltage having a magnitude related to the elapsed time from the opening of the first normally closed switch means, the magnitude of the voltage being a set value after an elapsed time equal to a minimum time required for the power torque wrench to properly tighten a threaded element; a second normally nonconducting switch means, the second normally nonconducting switch means being responsive to a voltage signal supplied thereto having a magnitude equal to or greater than a predetermined bias level for shifting to a conducting state; a second capacitor having one side coupled to the second normally nonconducting switch means; means responsive to the achievement of a predetermIned torque by the power torque wrench for applying the voltage charge on the first capacitor to the second side of the second capacitor to charge the second capacitor and supply a voltage pulse to the second normally nonconducting switch means, the voltage pulse having a magnitude equal to or greater than the predetermined bias level when the magnitude of the voltage on the first capacitor is equal to or greater than the set value; indicating means; and means responsive to the conduction of the second normally nonconducting switch means for coupling the indicating means in parallel with the DC power source to provide an indication of the proper tightening of the threaded element by the power torque wrench.
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) | 1977-07-22 | 1978-01-21 | 1978-07-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-07-22 | 1982-01-21 | 1982-07-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-07-22 | 1986-01-21 | 1986-07-23 | $7700.00 | Window Closed / Lapsed |