US3622972A — Brake failure warning pressure switches

Claim 1

Independent Claim 181 words

A switch for use in a dual fluid pressure system comprising a switch housing, a piston slidably disposed in a bore in said switch housing for movement from a neutral position in response to a fluid pressure unbalance, and a switch contact unit mounted on said switch housing; said switch contact unit including a contact unit housing mounted on said switch housing, a first terminal mounted on said contact unit housing and insulated from said switch housing, a first contact means operable to electrically connect said first terminal to said switch housing only when said piston is moved in said bore from said neutral position in response to a fluid pressure unbalance, and a second contact means operable to continuously electrically connect said first terminal to said switch housing in response to actuation of said first contact means by said movement of said piston, said second contact means maintaining said continuous electrical connection after deactuation of said first contact means by return of said piston to said neutral position, said second contact means being substantially encased within said contact unit housing.

Claim 2

Dependent Claim 181 words

A switch for use in a dual fluid pressure system comprising a switch housing, a piston slidably disposed in a bore in said switch housing for movement from a neutral position in response to a fluid pressure unbalance, and a switch contact unit mounted on said switch housing; said switch contact unit including a contact unit housing mounted on said switch housing, a first terminal mounted on said contact unit housing and insulated from said switch housing, a first contact means operable to electrically connect said first terminal to said switch housing only when said piston is moved in said bore from said neutral position in response to a fluid pressure unbalance, and a second contact means operable to continuously electrically connect said first terminal to said switch housing in response to actuation of said first contact means by said movement of said piston, said second contact means maintaining said continuous electrical connection after deactuation of said first contact means by return of said piston to said neutral position, said second contact means being substantially encased within said contact unit housing.

Claim 3

Dependent Claim 68 words

A switch as set forth in claim 1, wherein said second contact means includes a relay means, said relay means includes a coil disposed within said contact unit housing and a latching means disposed within said contact unit housing, said latching means being actuated by energization of said coil by said first contact means to continuously electrically connect said first terminal to said switch housing through said coil.

Claim 4

Dependent Claim 53 words

A switch as set forth in claim 2, wherein said first contact means includes a contact stud projecting into said bore in said switch housing, said piston engaging said contact stud when said piston is displaced by said pressure unbalance to electrically connect said first terminal to said switch housing through said coil.

Claim 5

Dependent Claim 20 words

A switch as set forth in claim 3, wherein said coil is wound upon a portion of said contact stud.

Claim 6

Dependent Claim 39 words

A switch as set forth in claim 3, wherein said contact stud is electrically insulated from said switch housing by an insulating sleeve, and said insulating sleeve includes an axially extending skirt portion upon which said coil is wound.

Claim 7

Dependent Claim 92 words

A switch as set forth in claim 2, including a second terminal mounted on said contact unit housing and insulated from said switch housing; said latching means includes a first normally open pole which is closed to electrically connect said first terminal to said switch housing through said coil when said latching means is actuated by said coil, and a second normally open pole which is closed to electrically connect said second terminal directly to said switch housing without passing through said coil when said latching means is actuated by said coil.

Claim 8

Dependent Claim 51 words

A switch as set forth in claim 2, including a second terminal mounted on said contact unit housing and insulated from said switch housing, and a diode, said latching means electrically connecting said second terminal to said switch housing through said diode when said latching means is actuated by said coil.

Claim 9

Dependent Claim 222 words

In a motor vehicle having a dual hydraulic brake system, a warning circuit for actuating an alarm device in response to a fluid pressure unbalance comprising a warning switch; said warning switch including a switch housing, a piston slidably disposed in an axial bore in said switch housing for movement in response to a fluid pressure unbalance, said piston being electrically connected to said switch housing, and a switch contact unit detachably mounted in a transverse bore in said switch housing intersecting said axial bore, said switch contact unit including a contact unit housing, a first terminal mounted on said contact unit housing and insulated from said switch housing, and a relay means mounted in said contact unit housing, said relay means including a coil and a latching means actuated by energization of said coil, said latching means continuously electrically connecting said first terminal to said switch housing through said coil when said piston is moved in response to a fluid pressure unbalance to engage a contact stud and electrically connect said first terminal to said switch housing through said coil and said piston; and a first conductor electrically connecting said first terminal to one side of said alarm device so that the warning circuit is completed through said alarm device when said first terminal is electrically connected to said switch housing.

Claim 10

Dependent Claim 222 words

In a motor vehicle having a dual hydraulic brake system, a warning circuit for actuating an alarm device in response to a fluid pressure unbalance comprising a warning switch; said warning switch including a switch housing, a piston slidably disposed in an axial bore in said switch housing for movement in response to a fluid pressure unbalance, said piston being electrically connected to said switch housing, and a switch contact unit detachably mounted in a transverse bore in said switch housing intersecting said axial bore, said switch contact unit including a contact unit housing, a first terminal mounted on said contact unit housing and insulated from said switch housing, and a relay means mounted in said contact unit housing, said relay means including a coil and a latching means actuated by energization of said coil, said latching means continuously electrically connecting said first terminal to said switch housing through said coil when said piston is moved in response to a fluid pressure unbalance to engage a contact stud and electrically connect said first terminal to said switch housing through said coil and said piston; and a first conductor electrically connecting said first terminal to one side of said alarm device so that the warning circuit is completed through said alarm device when said first terminal is electrically connected to said switch housing.

Claim 11

Dependent Claim 39 words

A warning circuit as set forth in claim 8 including a second conductor electrically connecting said one side of said alarm device to a prove-out switch, and said prove-out switch actuating said alarm device independently of said warning switch.

Claim 12

Dependent Claim 47 words

A warning circuit as set forth in claim 8 wherein said warning switch is electrically connected in parallel with said alarm device, a prove-out switch actuates said alarm device independently of said warning switch, and an isolation means prevents energization of said coil by said prove-out switch.

Claim 13

Dependent Claim 155 words

A warning circuit as set forth in claim 8 including a second terminal mounted on said contact unit housing and insulated from said switch housing, and a second conductor electrically connecting the other side of said alarm device to said second terminal, said latching means including a first normally open pole which is closed to electrically connect said first terminal to said switch housing through said coil when said latching means is actuated by said coil, and a second normally open pole which is closed to electrically connect said second terminal directly to said switch housing without passing through said coil when said latching means is actuated by said coil, a third conductor electrically connecting said other side of said alarm device to a prove-out switch, said prove-out switch actuating said alarm device independently of said warning switch, and said second normally opened pole preventing energization of said coil when said prove-out switch is operated.

Claim 14

Dependent Claim 115 words

A warning circuit as set forth in claim 8 including a second terminal mounted on said contact unit housing and insulated from said switch housing, and a diode in said contact unit housing, a second conductor electrically connecting said second terminal to the other side of said alarm device, said latching means electrically connecting said second terminal to said switch housing through said diode when said latching means is actuated by said coil, a third conductor electrically connecting said other side of said alarm device to a prove-out switch, said prove-out switch actuating said alarm device independently of said warning switch, and said diode preventing energization of said coil when said prove-out switch is operated.

Claim 15

Dependent Claim 225 words

A circuit comprising a power source, an alarm device, a prove-out circuit, and a warning circuit; said prove-out circuit including a means electrically connecting one side of said alarm device to one side of said power source, and a prove-out switch for connecting the other side of said alarm device to the other side of said power source to test said alarm device; said warning circuit including a coil, a relay switch means actuated by energization of said coil, a means electrically connecting one side of said coil to said one side of said power source, a means electrically connecting the other side of said coil to one side of said relay switch means, a means electrically connecting the other side of said relay switch means to said other side of said power source, a warning switch, a means electrically connecting said other side of said coil to one side of said warning switch, a means electrically connecting the other side of said warning switch to said other side of said power source, momentary actuation of said warning switch energizing said coil to actuate said relay switch means, said actuation of said relay switch means continuously actuating said alarm device, and an isolation means substantially isolating said prove-out circuit from said warning circuit to prevent energization of said coil by actuation of said prove-out switch.

Claim 16

Dependent Claim 225 words

A circuit comprising a power source, an alarm device, a prove-out circuit, and a warning circuit; said prove-out circuit including a means electrically connecting one side of said alarm device to one side of said power source, and a prove-out switch for connecting the other side of said alarm device to the other side of said power source to test said alarm device; said warning circuit including a coil, a relay switch means actuated by energization of said coil, a means electrically connecting one side of said coil to said one side of said power source, a means electrically connecting the other side of said coil to one side of said relay switch means, a means electrically connecting the other side of said relay switch means to said other side of said power source, a warning switch, a means electrically connecting said other side of said coil to one side of said warning switch, a means electrically connecting the other side of said warning switch to said other side of said power source, momentary actuation of said warning switch energizing said coil to actuate said relay switch means, said actuation of said relay switch means continuously actuating said alarm device, and an isolation means substantially isolating said prove-out circuit from said warning circuit to prevent energization of said coil by actuation of said prove-out switch.

Claim 17

Dependent Claim 66 words

A circuit as set forth in claim 13 wherein said isolation means includes a second relay switch means actuated by energization of said coil, a means electrically connecting one side of said second relay switch means to said other side of said alarm device, and a means electrically connecting the other side of said second relay switch means to said other side of said power source.

Claim 18

Dependent Claim 51 words

A circuit as set forth in claim 13 wherein said isolation means includes a diode, a means electrically connecting one side of said diode to said other side of said alarm device, and a means electrically connecting the other side of said diode to said one side of said warning switch.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1974-11-22	1975-05-24	1975-11-23	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1978-11-22	1979-05-24	1979-11-23	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1982-11-22	1983-05-24	1983-11-23	$7700.00	Window Closed / Lapsed

Brake failure warning pressure switches

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