US3693474A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Multiple fulcrum valve operating lever
Assignee: NORTHWEST ENGINEERING Co A CORP OF
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Filing: 1971-02-16
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Granted: 1972-09-26
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Expires: 1991-02-16
Abstract
Abstract A pivotal control lever for a valve stem has two differently spaced fulcrum connections with a base, one through a pin and slot connection and the other through a floating abutment which is held in a normal position by opposite springs. Initial pivotal movement of the lever is about the abutment, but when the limit of movement of the pin-slot connection is reached the lever begins to pivot about that connection, overriding the springs. In one form, deadband reduction is achieved by having the abutment radially further from the connection between the lever and stem than the pin and slot. A second form has the abutment closer to enhance initial control. A modification of the second form has a lost motion connection between the lever and the abutment and a torsion spring between the lever and stem which provides, in effect, an infinite lever to reduce deadband. Another form simply uses the torsion spring with a lost motion connection to reduce deadband.
Inventors
- 👤 Robert E Trick
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 15:16
CPC Classifications
G; G05; G05G; G05G1/00; G05G1/04; E; E02; E02F; E02F9/00; E02F9/20; E02F9/2004; F; F16; F16K; F16K31/00; F16K31/44; G05G5/00; G05G5/03; Y; Y10; Y10T; Y10T74/00; Y10T74/20; Y10T74/20396; Y10T74/20558; Y10T74/2057; Y10T74/20576; Y10T74/20582; Y10T74/206
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
237 words
In a control lever arrangement for a directional control valve or the like having an axially movable stem operatively connected to a control lever fulcrumed on a fixed base, which lever is pivotally movable between a normal position and at least one actuated position to cause corresponding axial movement of the stem, the improvement wherein: there are two fulcrum connections between the lever and the base which are differently spaced with respect to the point of connection between the lever and the stem; one of said fulcrum connections comprises a pin and slot connection which allows the lever limited movement with respect to the base as the lever begins to move toward actuated position; and the other of said connections comprises an abutment operatively connected to the base and pivotally connected to the lever to define a fulcrum, there being bias means operatively interposed between the abutment member and the base which holds the abutment member in a normal position with respect to the base, but which can be overriden as the lever completes its movement toward actuated position, initial movement of the lever toward actuated position causing the lever to pivot about the fulcrum defined by the abutment member until the limit of movement afforded by the pin and slot connection has been reached, further movement of the lever then causing the lever to pivot about the pin and slot connection and override the bias means.
Claim 2
Dependent Claim
237 words
In a control lever arrangement for a directional control valve or the like having an axially movable stem operatively connected to a control lever fulcrumed on a fixed base, which lever is pivotally movable between a normal position and at least one actuated position to cause corresponding axial movement of the stem, the improvement wherein: there are two fulcrum connections between the lever and the base which are differently spaced with respect to the point of connection between the lever and the stem; one of said fulcrum connections comprises a pin and slot connection which allows the lever limited movement with respect to the base as the lever begins to move toward actuated position; and the other of said connections comprises an abutment operatively connected to the base and pivotally connected to the lever to define a fulcrum, there being bias means operatively interposed between the abutment member and the base which holds the abutment member in a normal position with respect to the base, but which can be overriden as the lever completes its movement toward actuated position, initial movement of the lever toward actuated position causing the lever to pivot about the fulcrum defined by the abutment member until the limit of movement afforded by the pin and slot connection has been reached, further movement of the lever then causing the lever to pivot about the pin and slot connection and override the bias means.
Claim 3
Dependent Claim
83 words
The arrangement of claim 1 wherein, the lever is pivotally movable to two actuated positions on opposite sides of its normal position; the pin and slot connection allows limited movement of the lever relative to the base as it begins to move toward either actuated position; and there are two bias means of the abutment which together hold the abutment in its normal position, the bias means being adapted to be respectively overridden as the lever completes its movement toward either actuated position.
Claim 4
Dependent Claim
73 words
The arrangement of claim 2 wherein, the abutment comprises an elongated member pivotally connected at one end to the lever and has a radially extending spring seat near its opposite end; there is a closed, generally cylindrical housing pivotally connected to the base which axially slidably receives the opposite end of the elongated member; and the bias means comprises two compression springs seated between the spring seat and respective ends of the housing.
Claim 5
Dependent Claim
114 words
The arrangement of claim 2 wherein, there is an operative pivotal connection between the lever and stem; the fulcrum defined by the abutment is closer to the pivotal connection than the fulcrum defined by the pin and slot connection; there is a lost motion connection between the lever and the abutment which allows limited movement of the lever relative to the base as the lever begins its move toward either actuated position, the extent of such movement being less than that allowed by the pin and slot connection; and there is a torsion spring interposed between the lever and stem which resists pivotal movement of the lever In either direction relative to the stem.
Claim 6
Dependent Claim
153 words
In a control lever arrangement for a directional control valve or the like having an axially movable stem operatively pivotally connected to a control lever fulcrumed on a fixed base, which lever is pivotally movable between a normal and at least one actuated position to cause corresponding movement of the stem, the improvement wherein: the fulcrum comprises a lost motion connection which allows the lever limited movement with respect to the base as the lever begins to move toward actuated position; and there is a torsion spring interposed between the lever and the stem which resists pivotal movement of the lever relative to the stem so that initial movement of the lever from a normal position is linear, such linear movement continuing until the limit of movement afforded by the lose motion connection has been reached, further movement then causing the lever to pivot about the lost motion connection overriding the torsion spring.
Claim 7
Dependent Claim
153 words
In a control lever arrangement for a directional control valve or the like having an axially movable stem operatively pivotally connected to a control lever fulcrumed on a fixed base, which lever is pivotally movable between a normal and at least one actuated position to cause corresponding movement of the stem, the improvement wherein: the fulcrum comprises a lost motion connection which allows the lever limited movement with respect to the base as the lever begins to move toward actuated position; and there is a torsion spring interposed between the lever and the stem which resists pivotal movement of the lever relative to the stem so that initial movement of the lever from a normal position is linear, such linear movement continuing until the limit of movement afforded by the lose motion connection has been reached, further movement then causing the lever to pivot about the lost motion connection overriding the torsion spring.
Claim 8
Dependent Claim
62 words
The arrangement of claim 5 wherein, the lever is pivotally movable to two actuated positions on opposite sides of its normal position, the lost motion connection allows limited movement of the lever relative to the base as it begins to move toward either actuated position; and the torsion spring resists pivotal movement of the lever in either direction relative to the stem.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-09-26 | 1976-03-27 | 1976-09-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-09-26 | 1980-03-27 | 1980-09-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-09-26 | 1984-03-27 | 1984-09-26 | $7700.00 | Window Closed / Lapsed |