Patent US4909357A successfully refreshed from Google Patents.
US4909357A
Expired / Lapsed
US
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Safety device for a jacking system including a plurality of jacks designed for simultaneous operation
Assignee: Sugiyasu Industries Co Ltd
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Filing: 1988-02-09
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Granted: 1990-03-20
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Expires: 2008-02-09
Abstract
Abstract A safety device for a jacking system comprising a plurality of jacks which are designed for simultaneous operation, at least one table supported on the jacks, and a mechanism connecting the jacks for their simultaneous operation. Each jack is provided with a hydraulic or pneumatic cylinder for moving the jack to raise and lower the table, a pawl and rack mechanism which is normally held in its engaged position for holding the table in its raised position, and an AC solenoid connected to the pawl and rack mechanism for moving it to its disengaged position to allow the table to be lowered. The device includes a resistor connected in series to the solenoid. An integrating circuit is connected in parallel to the resistor, includes a capacitor and produces an electrical signal indicating any failure of the pawl and rack mechanism to be moved to its disengaged position. A relay is connected in parallel to the capacitor for operation in response to the signal to stop any lowering motion of the cylinder.
Inventors
- 👤 Hiroyuki Kawada
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 16:31
CPC Classifications
B; B66; B66F; B66F7/00; B66F7/06; B66F7/065; B66F7/0666; B66F7/08
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
182 words
In a safety device for a jacking system comprising a plurality of jacks which are designed for simultaneous operation, at least one cargo table supported on said jacks, and a mechanism connecting said jacks for their simultaneous operation, each of said jacks being provided with a fluid pressure-operated cylinder for moving said jack to raise and lower said table, and further provided with a pawl and rack mechanism which is normally held in its engaged position for holding said table in its raised position, and an AC solenoid connected to each said pawl and rack mechanism for moving it to its disengaged position to allow said table to be lowered, the improvement which comprises: a resistor connected in series to said solenoid; an integrating circuit connected in parallel to said resistor and including capacitor means for producing an electrical signal indicating any failure of said pawl and rack mechanism to be moved to its disengaged position; and relay means connected in parallel to said capacitor for operation in response to said signal to stop any lowering motion of each of said cylinders.
Claim 2
Dependent Claim
182 words
In a safety device for a jacking system comprising a plurality of jacks which are designed for simultaneous operation, at least one cargo table supported on said jacks, and a mechanism connecting said jacks for their simultaneous operation, each of said jacks being provided with a fluid pressure-operated cylinder for moving said jack to raise and lower said table, and further provided with a pawl and rack mechanism which is normally held in its engaged position for holding said table in its raised position, and an AC solenoid connected to each said pawl and rack mechanism for moving it to its disengaged position to allow said table to be lowered, the improvement which comprises: a resistor connected in series to said solenoid; an integrating circuit connected in parallel to said resistor and including capacitor means for producing an electrical signal indicating any failure of said pawl and rack mechanism to be moved to its disengaged position; and relay means connected in parallel to said capacitor for operation in response to said signal to stop any lowering motion of each of said cylinders.
Claim 3
Dependent Claim
25 words
A device as set forth in claim 1, wherein said integrating circuit includes a diode and a resistor connected in series to said capacitor means.
Claim 4
Dependent Claim
40 words
A device as set forth in claim 2, further including a resistor connected in series to said solenoid in each of said jacks and in parallel to a serially connected combination of a diode, a resistor and said relay means.
Claim 5
Dependent Claim
31 words
A device as set forth in claim 3, wherein said jacking system comprises a pair of scissors jacks and a pair of cargo tables each supported on one of said jacks.
Claim 6
Dependent Claim
15 words
A device as set forth in claim 4, wherein said cylinder is a hydraulic cylinder.
Claim 7
Dependent Claim
24 words
A device as set forth in claim 5, wherein said system is one which is used for lifting a motor vehicle when repairing it.
Claim 8
Dependent Claim
40 words
A device as set forth in claim 1, further including a resistor connected in series to said solenoid in each of said jacks and in parallel to a serially connected combination of a diode, a resistor and said relay means.
Claim 9
Dependent Claim
31 words
A device as set forth in claim 7, wherein said jacking system comprises a pair of scissors jacks and a pair of cargo tables each supported on one of said jacks.
Claim 10
Dependent Claim
15 words
A device as set forth in claim 8, wherein said cylinder is a hydraulic cylinder.
Claim 11
Dependent Claim
24 words
A device as set forth in claim 9, wherein said system is one which is used for lifting a motor vehicle when repairing it.
Claim 12
Dependent Claim
157 words
In a platform jack of the type having a plurality of jack cylinders and a cargo table operatively raised and lowered thereby, and having a pawl and rack mechanism associated with one jack cylinder of the plurality of jack cylinders and which is normally held in its engaged position for holding said table in its raised position, and an AC solenoid connected to said pawl and rack mechanism for moving it to its disengaged position to allow said table to be lowered, the improvement which comprises: a resistor connected in series to said solenoid; an integrating circuit connected in parallel to said resistor and including a capacitor means for producing an electrical signal indicating any failure of said pawl and rack mechanism to be moved to its disengaged position; and a relay means connected in parallel to said capacitor for operation in response to said signal to stop any lowering motion of the plurality of jack cylinders.
Claim 13
Dependent Claim
157 words
In a platform jack of the type having a plurality of jack cylinders and a cargo table operatively raised and lowered thereby, and having a pawl and rack mechanism associated with one jack cylinder of the plurality of jack cylinders and which is normally held in its engaged position for holding said table in its raised position, and an AC solenoid connected to said pawl and rack mechanism for moving it to its disengaged position to allow said table to be lowered, the improvement which comprises: a resistor connected in series to said solenoid; an integrating circuit connected in parallel to said resistor and including a capacitor means for producing an electrical signal indicating any failure of said pawl and rack mechanism to be moved to its disengaged position; and a relay means connected in parallel to said capacitor for operation in response to said signal to stop any lowering motion of the plurality of jack cylinders.
References Cited (Backward Citations)
US3796282A
Cited
US4724930A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-03-19 | 1993-09-18 | 1994-03-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-03-19 | 1997-09-18 | 1998-03-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-03-19 | 2001-09-18 | 2002-03-20 | $7700.00 | Window Closed / Lapsed |