US4878041A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Hydraulic master cylinder switch
Assignee: Automotive Products USA Inc
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Filing: 1988-12-02
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Granted: 1989-10-31
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Expires: 2008-12-02
Abstract
Abstract An electrical switch operated by the input member of a hydraulic master cylinder and controlling the stop signal lights of a motor vehicle, when associated with the master cylinder of a hydraulic brake system, and/or controlling a cruise control disconnect circuit. When associated with the master cylinder of a clutch hydraulic control system, the switch is adapted to close an interlock circuit allowing the motor vehicle driver to start the engine only when the clutch is fully released, and to operate a cruise control disconnect circuit upon small displacement of the input member from its home position.
Inventors
- 👤 Keith V. Leigh-Monstevens
- 👤 Richard A. Nix
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 20:37
CPC Classifications
H; H01; H01H; H01H13/00; H01H13/02; H01H13/10; H01H13/50; H01H13/64
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
358 words
A hydraulic master cylinder assembly for a control system of a motor vehicle, said assembly comprising: (A) a master cylinder filled with hydraulic fluid; (B) a piston mounted within said master cylinder; (C) a rigid input rod including a first end portion projecting into one end of said master cylinder for connection to said piston, a second end portion including means for connection to a control device for the motor vehicle control system, and an elongated central portion rigidly secured to said first and second end portions and extending outside of said master cylinder between said end portions, said input rod being moved axially in response to operator actuation of the control device to move said piston axially in said cylinder and eject hydraulic fluid under pressure form said cylinder; (D) a hollow switch housing mounted proximate said central input rod portion and extending axially along said rod portion from a first housing end proximate said one end of said master cylinder to a second housing end remote from said one end of said master cylinder; (E) a plunger mounted within the hollow of said housing and movable reciprocally within said housing hollow between a location proximate said first end of said housing to a location proximate said second end of said sousing; (F) a spring within said housing hollow urging said plunger toward one of said first and second ends of said housing; (G) a series of axially spaced electrical contacts mounted in axially spaced location along an internal surface of the hollow of said housing in juxtaposition to the reciprocal path of said plunger within said housing hollow; (H) means operative in response to axial movement of said input rod in response to operator actuation of the control device to move said plunger axially within said housing hollow against the resistance of said spring into successive juxtaposition with said series of electrical contacts; and (I) means on said plunger operative to successively coact with each of said series of electrical contacts upon successive movement of said plunger into juxtaposition with said contracts to successively make or break vehicular electrical control circuits respectively controlled by said contacts.
Claim 2
Dependent Claim
358 words
A hydraulic master cylinder assembly for a control system of a motor vehicle, said assembly comprising: (A) a master cylinder filled with hydraulic fluid; (B) a piston mounted within said master cylinder; (C) a rigid input rod including a first end portion projecting into one end of said master cylinder for connection to said piston, a second end portion including means for connection to a control device for the motor vehicle control system, and an elongated central portion rigidly secured to said first and second end portions and extending outside of said master cylinder between said end portions, said input rod being moved axially in response to operator actuation of the control device to move said piston axially in said cylinder and eject hydraulic fluid under pressure form said cylinder; (D) a hollow switch housing mounted proximate said central input rod portion and extending axially along said rod portion from a first housing end proximate said one end of said master cylinder to a second housing end remote from said one end of said master cylinder; (E) a plunger mounted within the hollow of said housing and movable reciprocally within said housing hollow between a location proximate said first end of said housing to a location proximate said second end of said sousing; (F) a spring within said housing hollow urging said plunger toward one of said first and second ends of said housing; (G) a series of axially spaced electrical contacts mounted in axially spaced location along an internal surface of the hollow of said housing in juxtaposition to the reciprocal path of said plunger within said housing hollow; (H) means operative in response to axial movement of said input rod in response to operator actuation of the control device to move said plunger axially within said housing hollow against the resistance of said spring into successive juxtaposition with said series of electrical contacts; and (I) means on said plunger operative to successively coact with each of said series of electrical contacts upon successive movement of said plunger into juxtaposition with said contracts to successively make or break vehicular electrical control circuits respectively controlled by said contacts.
Claim 3
Dependent Claim
46 words
A hydraulic master cylinder assembly according to claim 1 wherein: (J) said means on said plunger includes an electrical contact mounted on said plunger and movable axially with said plunger in response to axial movement of said input rod into selective engagement with axially spaced contacts.
Claim 4
Dependent Claim
60 words
A hydraulic master cylinder assembly according to claim 1 wherein: (J) said operative means includes means on said input rod defining a shoulder facing toward said master cylinder for pushing engagement with said plunger; and (K) said spring operates to urge a surface on said plunger into abutting engagement with said shoulder to define the rest position of said switch.
Claim 5
Dependent Claim
42 words
A hydraulic master cylinder assembly according to claim 1, wherein: (J) the hollow of said housing is positioned in surrounding relation to said central input rod portion; and (K) said plunger is mounted on said input rod central portion for movement therewith.
Claim 6
Dependent Claim
46 words
A hydraulic master cylinder assembly according to claim 4 wherein: (L) said switch housing has a U configuration in transverse cross section so as to enable said housing to be moved transversely from one side of said input rod into surrounding relation with said input rod.
Claim 7
Dependent Claim
54 words
A hydraulic master cylinder assembly according to claim 5 wherein: (M) said plunger has a U configuration matching that of said housing and so as to enable said housing and plunger to be moved transversely as a subassembly from one side of said input rod portion into surrounding relation to said input rod portion.
Claim 8
Dependent Claim
27 words
The switch of claim 1 wherein said plunger projects from said housing hollow for engagement at its free end with a stationary portion of said master cylinder.
Claim 9
Dependent Claim
31 words
The switch of claim 1 wherein said master cylinder is the master cylinder of a hydraulic clutch control system and one of said circuits is a starter motor relay interlock circuit.
Claim 10
Dependent Claim
16 words
The switch of claim 8 wherein another one of said circuits is a cruise control circuit.
Claim 11
Dependent Claim
18 words
The switch of claim 1 wherein said housing is mounted on said one end of said master cylinder.
Claim 12
Dependent Claim
119 words
A hydraulic master cylinder assembly including: (A) a cylinder defining an axial bore; (B) a piston mounted for axial sliding movement in said bore; (C) a solid, rigid pushrod extending axially into said bore through the rear end of said cylinder, connected at its forward end to said piston, and extending at its rear end rearwardly out of said cylinder; and (D) a switch including a housing mounted on said pushrod rearwardly of said cylinder, at least one electrical contact carried by said housing and adapted to control an electrical control circuit, and actuator means operative in response to axial movement of said pushrod into said cylinder bore to coact with said contact to make or break said circuit.
Claim 13
Dependent Claim
119 words
A hydraulic master cylinder assembly including: (A) a cylinder defining an axial bore; (B) a piston mounted for axial sliding movement in said bore; (C) a solid, rigid pushrod extending axially into said bore through the rear end of said cylinder, connected at its forward end to said piston, and extending at its rear end rearwardly out of said cylinder; and (D) a switch including a housing mounted on said pushrod rearwardly of said cylinder, at least one electrical contact carried by said housing and adapted to control an electrical control circuit, and actuator means operative in response to axial movement of said pushrod into said cylinder bore to coact with said contact to make or break said circuit.
Claim 14
Dependent Claim
69 words
A hydraulic master cylinder assembly according to claim 11 wherein: (E) said switch includes a plurality of axially spaced contacts carried on said housing and adapted to respectively control a plurality of electrical controlled circuits; and (F) said actuator means is operative in response to axial movement of said pushrod into said cylinder bore to successively coat with said axially spaced contacts to successively make or break said circuits.
Claim 15
Dependent Claim
69 words
A hydraulic master cylinder assembly according to claim 11 wherein: (E) said housing is hollow; (F) said pushrod extends through the hollow of said housing; and (G) said actuator means comprises a plunger positioned in the hollow of said housing and directly drivingly connected to said pushrod so as to be moved axially within said switch housing in response to axial movement of said pushrod into said cylinder bore.
Claim 16
Dependent Claim
34 words
A hydraulic cylinder assembly according to claim 13 wherein: (A) said plunger is mounted on said pushrod and abuttingly engages a shoulder on said pushrod so as to be directly driven by said pushrod.
Claim 17
Dependent Claim
35 words
A hydraulic master cylinder assembly according to claim 14 wherein: (I) said switch further includes a spring positioned in the hollow of said housing and urging said plunger into abutting engagement with said pushrod shoulder.
Claim 18
Dependent Claim
69 words
A hydraulic master cylinder assembly according to claim 15 wherein: (J) a plurality of axially spaced contacts are mounted in the hollow of said housing in confronting relation to said pushrod; (K) each contact controls an electrical control circuit; and (L) said plunger successively coacts with each of said contacts in response to axial movement of said pushrod into said cylinder bore to successively make or break said circuits.
Claim 19
Dependent Claim
36 words
A hydraulic master cylinder assembly according to claim 16 wherein: (M) said plunger includes an electrical contact respectively and successively coacting with said axially spaced contacts as said pushrod is moved axially into said cylinder bore.
Claim 20
Dependent Claim
42 words
A hydraulic master cylinder assembly according to claim 11 wherein: (E) said switch housing has a U configuration in transverse cross section so as to allow said switch to be mounted onto said pushrod with a transverse movement relative to said pushrod.
Claim 21
Dependent Claim
62 words
A hydraulic master cylinder assembly according to claim 18 wherein: (F) said housing is hollow; and (G) said actuator means comprises a U-shaped plunger positioned within the hollow of said housing with its opening aligned with the opening of said housing to allow said housing and said plunger to be moved transversely onto said pushrod to mount said switch on said pushrod.
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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) | 1992-10-30 | 1993-05-01 | 1993-10-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-10-30 | 1997-05-01 | 1997-10-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-10-30 | 2001-05-01 | 2001-10-31 | $7700.00 | Window Closed / Lapsed |