US3782653A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Web tension control apparatus
Assignee: Masson Scott Thrissell Engineering Ltd
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Filing: 1972-03-20
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Granted: 1974-01-01
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Expires: 1992-03-20
Abstract
Abstract A travelling web being wound onto or unwound from a reel has its tension sensed by a dancer roll in a web loop, and the position of the dancer roll is used to control the drive or brake system of the reel to maintain the tension uniform. With pneumatic control, a valve in the air line is actuated by the dancer roll to increase or decrease the supply, and in addition there is feedback from the air line to operate devices which restore the valve to its median position. These devices act in opposition, one acting faster than the other to cause the initial restoration movement. There is a resultant phase difference between dancer roll movement and valve actuation, which can be further modified by interposition of a mechanical phase shifting device between the dancer roll and valve.
Inventors
- 👤 Jones G Scott
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 05:37
CPC Classifications
B; B65; B65H; B65H23/00; B65H23/04; B65H23/06; B65H23/063; B65H23/044; G; G01; G01L; G01L5/00; G01L5/04; G01L5/08; B65H2403/00; B65H2403/70; B65H2403/72; B65H2403/725; B65H2403/7253
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
168 words
A web tension control apparatus for a travelling web tensioned by a fluid operated web drive/brake system, the tension control apparatus including a sensor co-operating with the web to produce a physical displacement in either of two opposite directions depending on increase or decrease of tension either side of a norm, a fluid control valve which governs the supply to said drive/brake system and which is responsive to said physical displacement to restore the tension towards said norm, and feedback means to said valve from said supply downstream of the valve to resist the valve movement caused by said sensor and, after a delay, to assist said movement, wherein the improvement comprises introducing delay means into the feedback that resists the valve movement, the assisting feedback being still further delayed, and providing a resilient connectioN between the sensor and the valve which is sufficiently stiff to transmit said physical displacement for actuating the valve but which substantially eliminates a force reaction from the valve back to the sensor.
Claim 2
Dependent Claim
168 words
A web tension control apparatus for a travelling web tensioned by a fluid operated web drive/brake system, the tension control apparatus including a sensor co-operating with the web to produce a physical displacement in either of two opposite directions depending on increase or decrease of tension either side of a norm, a fluid control valve which governs the supply to said drive/brake system and which is responsive to said physical displacement to restore the tension towards said norm, and feedback means to said valve from said supply downstream of the valve to resist the valve movement caused by said sensor and, after a delay, to assist said movement, wherein the improvement comprises introducing delay means into the feedback that resists the valve movement, the assisting feedback being still further delayed, and providing a resilient connectioN between the sensor and the valve which is sufficiently stiff to transmit said physical displacement for actuating the valve but which substantially eliminates a force reaction from the valve back to the sensor.
Claim 3
Dependent Claim
43 words
A web tension control apparatus according to claim 1, wherein said feedback means includes a pair of fluid operated actuating devices arranged to act in opposite senses on the valve and supplied through respective delay means for the supply to the drive/brake system.
Claim 4
Dependent Claim
53 words
A web tension control apparatus according to claim 2, wherein a floating lever is connected at one point to said sensor, at another point between said actuating devices and at a third point to the valve, the resilience of the connection between the sensor and the valve being provided by said actuating devices.
Claim 5
Dependent Claim
40 words
A web tension control apparatus according to claim 3, wherein a link provides the connection between the lever and said valve and means responsive to the outlet pressure of said valve give negative feedback to the sensor through said link.
Claim 6
Dependent Claim
40 words
A web tension control apparatus according to claim 2, wherein said actuating devices comprise chambers with diaphragms that are linked to move together by a movable element of the valve, and wherein spring means interconnect said diaphragms and said sensor.
Claim 7
Dependent Claim
36 words
A web tension control apparatus according to claim 5, wherein a housing is spanned by said diaphragms, whereby two spaced fluid chambers are formed, and the valve element is disposed within the housing between the diaphragms.
Claim 8
Dependent Claim
33 words
A web tension control apparatus according to claim 6, wherein the housing is connected to move with the sensor and the spring means act between the inside of the housing and the diaphragms.
Claim 9
Dependent Claim
47 words
A web tension control apparatus according to claim 7, wherein a third diaphragm is provided to close off a space between itself and one of the other diaphragms, this space being in communication with the outlet of the valve to provide a negative feedback to the sensor.
Claim 10
Dependent Claim
104 words
A web tension control apparatus according to claim 6, wherein there are three parallel diaphragms, a valve spindle comprising said valve element linking said diaphragms, a fixed housing mounting said diaphragms and providing two closed spaces at opposite sides of the central diaphragm, separate passageways which communicate between each of said two closed spaces and said pressure fluid line, restriction of different throttling characteristics disposed in said separate passageways to give two different time delays, and spring means normally balancing the diaphragm-spindle assembly against the pressure of fluid in said line, said input signal being applied through said resilient connection to said valve spindle.
Claim 11
Dependent Claim
51 words
A web tension control apparatus according to claim 9, wherein said valve is a poppet valve and the fluid pressure in said line is applied to a chamber defined by an outer diaphragm, the housing, and the head of the poppet valve which, when balanced, permits leakage of the pressure fluid.
Claim 12
Dependent Claim
39 words
A web tension control apparatus according to claim 9, wherein the valve is constituted by an end of said spindle co-operating with an orifice from which the fluid under pressure jets to an extent determined by the spindle position.
Claim 13
Dependent Claim
52 words
A web tension control apparatus according to claim 9, wherein the valve has two elements on said spindle at opposite ends of a throat, the fluid under pressure being normally directed past one said element and into said line, which communicates with said throat, and also past said other element as leakage.
Claim 14
Dependent Claim
119 words
A web tension control apparatus according to claim 1, wherein said resilient connection includes a mechanical phase shifting system comprising a combination of spring means and viscous damping means arranged so that the input thereto results in a modified output at another point with low gain at low input frequencies and gain increasing with frequency over said middle band of frequencies, the system including an assembly of first spring means and visCous damping means coupled in parallel, second spring means in series therewith, and a fixed structure against which said second spring means react, the input being to the free end of said assembly and the output from a point effectively intermediate said assembly and said second spring means.
Claim 15
Dependent Claim
52 words
A web tension control apparatus according to claim 12, wherein said viscous damping means is a rotary dashpot arranged to be partially rotated by said input, the first spring means acting between the dashpot body and an output member and the second spring means acting between a fixed structure and said member.
Claim 16
Dependent Claim
22 words
A web tension control apparatus according to claim 13, wherein said second spring means is stiff compared with said first spring means.
Claim 17
Dependent Claim
121 words
A web tension control apparatus according to claim 1, wherein said resilient connection includes a mechanical phase shifting system comprising a combination of spring means and viscous damping means arranged so that the input thereto results in a modified output at another point with low gain at low input frequencies and gain increasing with frequency over said middle band of frequencies, the system including an assembly of first viscous damping means, spring means and second viscous damping means in series to one end of which assembly the input is applied and the other end of which reacts against a fixed strcture, the output being from a point effectively between the spring means and the viscous damping means at said one end.
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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) | 1976-12-31 | 1977-07-02 | 1978-01-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-12-31 | 1981-07-02 | 1982-01-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-12-31 | 1985-07-02 | 1986-01-01 | $7700.00 | Window Closed / Lapsed |