US3825244A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Hydraulically lockable lifting device
Assignee: Suspa Federungstechnik GmbH
•
Filing: 1972-12-29
•
Granted: 1974-07-23
•
Expires: 1992-12-29
Abstract
Abstract A hydraulically lockable lifting device particularly adapted for height adjustment of tables comprising a gas spring in which a piston mounted in a piston rod and acting against compressed gas travels in a tube which is sealed with respect to the outside, wherein both sides of the piston are connected by an openable passage that connects chambers filled with an incompressible medium and a pump for pumping the incompressible medium from one chamber into the other.
Inventors
- 👤 F Bauer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 22:15
CPC Classifications
A; A47; A47C; A47C3/00; A47C3/20; A47C3/30; A47B; A47B9/00; A47B9/10
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
152 words
In a hydraulically lockable lifting device, particularly adapted for height adjustment of tables, comprising a gas spring, in which a piston, subject to the action of compressed gas and mounted on a piston rod, is fitted in a tube which is sealed with respect to the outside, and with chambers provided which are filled with an incompressible medium and are located on both sides of the piston, said chambers linked by a closable connecting passage, the improvement wherein a pump is provided to pump the incompressible medium from one chamber into the other, and wherein the chamber for the incompressible medium located on that side of the piston which faces the compressed gas is mounted in a separate tube in which an auxiliary piston is mounted by means of seals, said auxiliary piston serving to seal off the gas chamber from this chamber, and resting against the piston or fastened to it.
Claim 2
Dependent Claim
152 words
In a hydraulically lockable lifting device, particularly adapted for height adjustment of tables, comprising a gas spring, in which a piston, subject to the action of compressed gas and mounted on a piston rod, is fitted in a tube which is sealed with respect to the outside, and with chambers provided which are filled with an incompressible medium and are located on both sides of the piston, said chambers linked by a closable connecting passage, the improvement wherein a pump is provided to pump the incompressible medium from one chamber into the other, and wherein the chamber for the incompressible medium located on that side of the piston which faces the compressed gas is mounted in a separate tube in which an auxiliary piston is mounted by means of seals, said auxiliary piston serving to seal off the gas chamber from this chamber, and resting against the piston or fastened to it.
Claim 3
Dependent Claim
20 words
A device according to claim 1, wherein auxiliary piston is provided with a cavity that communicates with said gas chamber.
Claim 4
Dependent Claim
19 words
A device according to claim 1 wherein said auxiliary piston is longer than the maximum travel of said piston.
Claim 5
Dependent Claim
112 words
In a hydraulically lockable lifting device, particularly adapted for height adjustment of tables, comprising a gas spring, in which a piston, subject to the action of compressed gas and mounted on a piston rod, is fitted in a tube which is sealed with respect to the outside, and with chambers provided which are filled with an incompressible medium and are located on both sides of the piston, said chambers linked by a closable connecting passage, the improvement wherein a pump is provided to pump the incompressible medium from one chamber into the other, and wherein said pump is mounted coaxially with said gas spring and a valve device in a common housing.
Claim 6
Dependent Claim
112 words
In a hydraulically lockable lifting device, particularly adapted for height adjustment of tables, comprising a gas spring, in which a piston, subject to the action of compressed gas and mounted on a piston rod, is fitted in a tube which is sealed with respect to the outside, and with chambers provided which are filled with an incompressible medium and are located on both sides of the piston, said chambers linked by a closable connecting passage, the improvement wherein a pump is provided to pump the incompressible medium from one chamber into the other, and wherein said pump is mounted coaxially with said gas spring and a valve device in a common housing.
Claim 7
Dependent Claim
119 words
In a hydraulically lockable lifting device particularly adapted for height adjustment of tables, comprising a gas spring, in which a piston, subject to the action of compressed gas and mounted on a piston rod, is fitted in a tube which is sealed with respect to the outside, and with chambers provided which are filled with an incompressible medium and are located on both sides of the piston, said chambers linked by a closable connecting passage, the improvement wherein a pump is provided to pump the incompressible medium from one chamber into the other, and wherein an activating pin for said valve device and a pump piston rod for said pump are combined and brought together out of the housing.
Claim 8
Dependent Claim
119 words
In a hydraulically lockable lifting device particularly adapted for height adjustment of tables, comprising a gas spring, in which a piston, subject to the action of compressed gas and mounted on a piston rod, is fitted in a tube which is sealed with respect to the outside, and with chambers provided which are filled with an incompressible medium and are located on both sides of the piston, said chambers linked by a closable connecting passage, the improvement wherein a pump is provided to pump the incompressible medium from one chamber into the other, and wherein an activating pin for said valve device and a pump piston rod for said pump are combined and brought together out of the housing.
Claim 9
Dependent Claim
136 words
In a hydraulically lockable lifting device, particularly adapted for height adjustment of tables, comprising a gas spring, in which a piston, subject to the action of compressed gas and mounted on a piston rod, is fitted in a tube which is sealed with respect to the outside, and with chambers provided which are filled with an incompressible medium and are located on both sides of The piston, said chambers linked by a closable connecting passage, the improvement wherein a pump is provided to pump the incompressible medium from one chamber into the other; wherein said pump is made in the form of a plunger-piston pump; and wherein said plunger-piston pump comprises a pump piston provided with check valves and traveling in a working chamber, said piston being axially driven by means of a pump piston rod.
Claim 10
Dependent Claim
136 words
In a hydraulically lockable lifting device, particularly adapted for height adjustment of tables, comprising a gas spring, in which a piston, subject to the action of compressed gas and mounted on a piston rod, is fitted in a tube which is sealed with respect to the outside, and with chambers provided which are filled with an incompressible medium and are located on both sides of The piston, said chambers linked by a closable connecting passage, the improvement wherein a pump is provided to pump the incompressible medium from one chamber into the other; wherein said pump is made in the form of a plunger-piston pump; and wherein said plunger-piston pump comprises a pump piston provided with check valves and traveling in a working chamber, said piston being axially driven by means of a pump piston rod.
Claim 11
Dependent Claim
26 words
A device according to claim 6, wherein each of the two parts of the working chamber separated by said pump piston is provided with a chamber.
Claim 12
Dependent Claim
140 words
In a hydraulically lockable lifting device, particularly adapted for height adjustment of tables, comprising a gas spring, in which a piston, subject to the action of compressed gas and mounted on a piston rod, is fitted in a tube which is sealed with respect to the outside, and with chambers provided which are filled with an incompressible medium and are located on both sides of the piston, said chambers linked by a closable connecting passage, the improvement wherein a pump is provided to pump the incompressible medium from one chamber into the other, and wherein said pump serves simultaneously as a valve, said pump comprising a piston having a valve ring thereabout, a cylinder in which said piston moves, and axial bores extending through said cylinder for mating with said valve ring upon a predetermined travel distance of said piston.
Claim 13
Dependent Claim
140 words
In a hydraulically lockable lifting device, particularly adapted for height adjustment of tables, comprising a gas spring, in which a piston, subject to the action of compressed gas and mounted on a piston rod, is fitted in a tube which is sealed with respect to the outside, and with chambers provided which are filled with an incompressible medium and are located on both sides of the piston, said chambers linked by a closable connecting passage, the improvement wherein a pump is provided to pump the incompressible medium from one chamber into the other, and wherein said pump serves simultaneously as a valve, said pump comprising a piston having a valve ring thereabout, a cylinder in which said piston moves, and axial bores extending through said cylinder for mating with said valve ring upon a predetermined travel distance of said piston.
Claim 14
Dependent Claim
125 words
In a hydraulically lockable lifting device, particularly adapted for height adjustment of tables, comprising a gas spring, in which a piston, subject to the action of compressed gas and mounted on a piston rod, is fitted in a tube which is sealed with respect to the outside, and with chambers provided which are filled with an incompressible medium and are located on both sides of the piston, said chambers linked by a closable connecting passage, the improvement wherein a pump is provided to pump the incompressible medium from one chamber into the other, and wherein said pump serves simultaneously as a valve, wherein operating pins are provided for forcible opening of a check valve when said pump piston is at one terminus of its travel.
Claim 15
Dependent Claim
125 words
In a hydraulically lockable lifting device, particularly adapted for height adjustment of tables, comprising a gas spring, in which a piston, subject to the action of compressed gas and mounted on a piston rod, is fitted in a tube which is sealed with respect to the outside, and with chambers provided which are filled with an incompressible medium and are located on both sides of the piston, said chambers linked by a closable connecting passage, the improvement wherein a pump is provided to pump the incompressible medium from one chamber into the other, and wherein said pump serves simultaneously as a valve, wherein operating pins are provided for forcible opening of a check valve when said pump piston is at one terminus of its travel.
References Cited (Backward Citations)
No citation records indexed.
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 |