US4571864A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for tensioning rectangular pieces of fabric
Assignee: G BOPP & Co AG
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Filing: 1984-11-05
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Granted: 1986-02-25
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Expires: 2004-11-05
Abstract
Abstract A tensioning device includes a tensioning frame having stretcher bars disposed in parallel pairs and displaceable relative to one another, on which bars the edges of a piece of fabric can be clamped. Each stretcher bar has two cooperating clamping devices which extend over the entire length of the stretcher bar, each device being formed by a tube of elastic material adapted to be pneumatically or hydraulically pressurized. Each tube is held in aligned grooves in a closed row of longitudinally movable runners. The clamping force obtained through pressurization acts at every point over the entire length of the clamped edge of the piece of fabric. The elongation of the tubes, which can be increased by gradually raising the pressure, follows the stretching of the piece of fabric during the tensioning operation. The runners move apart during this process, but without losses of tension occurring because of the resulting gaps. Uniform tensioning of the pieces of fabric in line with the threads is thus possible.
Inventors
- 👤 Peter Bopp
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 20:05
CPC Classifications
B; B41; B41F; B41F15/00; B41F15/14; B41F15/34; B41F15/36
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
93 words
An apparatus for tensioning pieces of fabric comprising a tensioning frame, said frame comprising at least two pairs of opposed stretcher bars displaceable relative to one another, the stretcher bars having two cooperating clamping means opposed to one another for clamping a piece of fabric, the clamping means having a rail carrying a plurality of runners slidable thereon, the runners having a longitudinal groove receiving an expansible tube member extending the entire length of the stretcher bar and capable of radial and longitudinal expansion when pressurized, whereby the cooperating tubes clamp the fabric.
Claim 2
Independent Claim
93 words
An apparatus for tensioning pieces of fabric comprising a tensioning frame, said frame comprising at least two pairs of opposed stretcher bars displaceable relative to one another, the stretcher bars having two cooperating clamping means opposed to one another for clamping a piece of fabric, the clamping means having a rail carrying a plurality of runners slidable thereon, the runners having a longitudinal groove receiving an expansible tube member extending the entire length of the stretcher bar and capable of radial and longitudinal expansion when pressurized, whereby the cooperating tubes clamp the fabric.
Claim 3
Dependent Claim
97 words
An apparatus according to claim 1, wherein the stretcher bar has an upper and a lower part, these parts being movably joined together by a hinge extending along a longitudinal axis and being adapted to be fastened together in the folded state by a locking means, the upper and lower parts each carrying on the sides facing one another a rail on which the runners are positively held, such that the longitudinal grooves of the runners face one another and in which the tubes are embedded except for a free longitudinal portion required for the clamping function.
Claim 4
Dependent Claim
37 words
An apparatus according to claim 1, wherein the tubes are connected at one end of the stretcher bar to a supply pipe for the pressure medium and are closed at the other end of the stretcher bar.
Claim 5
Dependent Claim
36 words
An apparatus according to claim 1, wherein the runner rails are provided at one end with a stop for the runners, from which stop the longitudinal movement of the runners can take place in one direction.
Claim 6
Dependent Claim
30 words
An apparatus according to claim 1, wherein the runner rails are provided at their center with a stop member whereby the longitudinal movement of runners occur outwardly from the stop.
Claim 7
Dependent Claim
17 words
An apparatus according to claim 1, wherein a vertically adjustable table is disposed inside the tensioning frame.
Claim 8
Dependent Claim
19 words
An apparatus according to claim 6, wherein the table top is adapted to be moved out to one side.
Claim 9
Dependent Claim
34 words
An apparatus according to claim 6, where means are provided for enabling a frame disposed on the vertically adjustable table top to be pressed with preselectable contact pressure against the tensioned piece of fabric.
Claim 10
Dependent Claim
33 words
An apparatus according to claim 6, where retaining pins and eccentric discs are inserted in selectable positions on the table top to enable a frame laid on the table top to be pretensioned.
Claim 11
Dependent Claim
12 words
An apparatus according to claim 1, where the tube is pressurized pneumatically.
Claim 12
Dependent Claim
12 words
An apparatus according to claim 1, where the tube is pressurized hydraulically.
Claim 13
Dependent Claim
22 words
An apparatus according to claim 1, where the runners move longitudinally along the rail according to the longitudinal expansion of the tube.
Claim 14
Dependent Claim
22 words
An apparatus according to claim 1, where the gripping strength of the clamping means is determined by the pressure within the tube.
References Cited (Backward Citations)
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Cited
US4044669A
Cited
US3962805A
Cited
US3978905A
Cited
US4179830A
Cited
US4156399A
Cited
FR2486459A1
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-02-24 | 1989-08-26 | 1990-02-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-02-24 | 1993-08-26 | 1994-02-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-02-24 | 1997-08-26 | 1998-02-25 | $7700.00 | Window Closed / Lapsed |