US3893489A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for regulating the tension of warp threads in power looms
Assignee: Alfa Laval Bergedorfer Eisenwerke GmbH
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Filing: 1973-12-11
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Granted: 1975-07-08
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Expires: 1993-12-11
Abstract
Abstract A power loom wherein a dancer roll is urged against warp threads between the warp beam and the weaving station. The dancer roll engages the upper sides of the warp threads in a space between two cylindrical guides which engage the undersides of the warp threads. The dancer roll is urged against the warp threads with a constant force by two double-acting hydraulic cylinders whose upper chambers receive a pressurized hydraulic fluid from a pump through a conduit which contains an adjustable pressure regulating valve, a pressure accumulator and a check valve. A further valve is provided to connect the upper chambers with the tank while connecting the lower chambers of the cylinders to the pump so that the dancer roll rises above the guides to permit for convenient introduction of warp threads into the loom. The position of the dancer roll is monitored by a fluid flow regulating device which can adjust a variable-delivery pump for a variable-speed hydraulic motor which rotates the warp beam in a direction to pay out warp threads.
Inventors
- 👤 Friedrich Wilhelm Bassing
- 👤 Gottfried Gerhard Wil Hoffmann
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 18:33
CPC Classifications
D; D03; D03D; D03D49/00; D03D49/04; D03D49/06
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
234 words
In a power loom, a combination comprising a frame; at least one rotary warp beam; a variable-speed hydraulic motor for rotating said warp beam in a direction to pay out warp threads; means for collecting the fabric obtained by interweaving said warp threads with filling threads at a weaving station; and an arrangement for regulating the let-off of the warp threads with constant warp thread tension, said arrangement comprising: a. a pair of spaced-apart guides located between said warp beam and said weaving station and arranged to engate one side of each warp thread, b. a displaceable dancer roll resting in a bight of the warp threads between said guides and engaging the other side of each warp thread, c. a support member rotatably supporting said dancer roll, d. hydraulic cylinders connecting said support member to said frame and each having a piston reciprocably therein and defining at least one pressure chamber, e. conduit means connecting each pressure chamber to a source of pressurized hydraulic fluid for urging said dancer roll against the warp threads, f. an adjustable constant pressure regulating valve connected to said conduit means for maintaining a constant pressure in said pressure chambers irrespective of the position of said dancer roll, and g. regulating means continuously actuated by said support member for adjusting the flow of pressurized hydraulic fluid to said hydraulic motor in response to displacement of said dancer roll.
Claim 2
Dependent Claim
234 words
In a power loom, a combination comprising a frame; at least one rotary warp beam; a variable-speed hydraulic motor for rotating said warp beam in a direction to pay out warp threads; means for collecting the fabric obtained by interweaving said warp threads with filling threads at a weaving station; and an arrangement for regulating the let-off of the warp threads with constant warp thread tension, said arrangement comprising: a. a pair of spaced-apart guides located between said warp beam and said weaving station and arranged to engate one side of each warp thread, b. a displaceable dancer roll resting in a bight of the warp threads between said guides and engaging the other side of each warp thread, c. a support member rotatably supporting said dancer roll, d. hydraulic cylinders connecting said support member to said frame and each having a piston reciprocably therein and defining at least one pressure chamber, e. conduit means connecting each pressure chamber to a source of pressurized hydraulic fluid for urging said dancer roll against the warp threads, f. an adjustable constant pressure regulating valve connected to said conduit means for maintaining a constant pressure in said pressure chambers irrespective of the position of said dancer roll, and g. regulating means continuously actuated by said support member for adjusting the flow of pressurized hydraulic fluid to said hydraulic motor in response to displacement of said dancer roll.
Claim 3
Dependent Claim
18 words
A combination as defined in claim 1, wherein said dancer roll comprises a plurality of coaxial cylindrical sections.
Claim 4
Dependent Claim
25 words
A combination as defined in claim 1, wherein the diameter of said dancer roll equals or is slightly less than the distance between said guides.
Claim 5
Dependent Claim
49 words
A combination as defined in claim 1, and further comprising a variable-delivery hydraulic pump connected to said hydraulic motor, said regulating means being operatively connected with said support member and said hydraulic pump for chaning the delivery rate of said pump in response to displacement of said support member.
Claim 6
Dependent Claim
48 words
A combination as defined in claim 1, wherein said source of pressure fluid comprises a second hydraulic pump, said conduit means connecting said pressure chambers to said second hydraulic pump, and a pressure accumulator connected to said conduit means between said pressure chambers and said second hydraulic pump.
Claim 7
Dependent Claim
39 words
A combination as defined in claim 5, further comprising a check valve in said conduit means between said second hydraulic pump and said constant pressure regulating valve to prevent pressurized hydraulic fluid from flowing towards said second hydraulic pump.
Claim 8
Dependent Claim
112 words
A combination as defined in claim 5, wherein said hydraulic cylinders are double-acting cylinders and each comprising a first and and a pressure chamber separated by said piston, and including a hydraulic tank, said conduit means comprising a first conduit connected with said first chambers and a second conduit connected with said second chambers, and including a reversing valve connected to said conduits and movable between two positions in one of which it connects said first chambers to said second hydraulic pump and said second chambers to said tank and in the other of which it connects said first chambers to said tank and said second chambers to said second hydraulic pump.
Claim 9
Dependent Claim
30 words
A combination as defined in claim 1, wherein said hydraulic cylinders are connected to said frame and said pistons are provided with piston rods articulatedly connected to said support member.
Claim 10
Dependent Claim
24 words
A combination as defined in claim 1, wherein said hydraulic cylinders pull said dancer roll downwardly against the upper side of the warp threads.
Claim 11
Dependent Claim
61 words
A combination as defined in claim 7, wherein said dancer roll is normally located at a level below said guides and said hydraulic cylinders are adapted to move said dancer roll to a level above said guides by operating said reversing valve to connect said second pressure chambers to said hydraulic pump and said first pressure chambers to said hydraulic tank.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-07-07 | 1979-01-06 | 1979-07-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-07-07 | 1983-01-06 | 1983-07-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-07-07 | 1987-01-06 | 1987-07-08 | $7700.00 | Window Closed / Lapsed |