US3880049A — Dual valve operated pressure differential servomo…

Claim 1

Independent Claim 332 words

In a servomotor having a wall means for separating a front chamber from a rear chamber, control means for sequentially regulating the communication of vacuum, air at atmospheric pressure and air above atmospheric pressure to the rear chamber to develop an operational force from a pressure differential to operate a brake actuator in response to an input force, said control means comprising: first hub means connected to said wall means having a first housing with a first axial bore therein, said first housing having a first passage connecting the first axial bore with the front chamber, said housing having a second passage connecting the first axial bore with the rear chamber, said housing having a third passage connecting the first axial bore with the atmosphere; second hub means connected to said first hub means for transmitting the operational force to said brake actuator from said wall means, said sEcond hub means having a second housing with a second axial bore coaxial to said first axial bore, said second housing having an entrance port through which air above atmospheric pressure is communicated to the second bore; first valve means located in said first axial bore for controlling the communication of vacuum through the first passage; second valve means located in said second axial bore for controlling the communication of air above atmospheric pressure from the second bore; plunger means located in said first and second axial bores for progressively operating the first and second valve means in response to said input force; and check valve means connected to the third passage in the first hub means for allowing air at atmospheric pressure to be communicated to said second passage when vacuum communication through the first passage is interrupted by movement of the first valve means and for preventing air above atmospheric pressure from entering the third passage when air above atmospheric pressure is presented to the second passage upon movement of the second valve means in response to movement of the plunger means.

Claim 2

Dependent Claim 332 words

In a servomotor having a wall means for separating a front chamber from a rear chamber, control means for sequentially regulating the communication of vacuum, air at atmospheric pressure and air above atmospheric pressure to the rear chamber to develop an operational force from a pressure differential to operate a brake actuator in response to an input force, said control means comprising: first hub means connected to said wall means having a first housing with a first axial bore therein, said first housing having a first passage connecting the first axial bore with the front chamber, said housing having a second passage connecting the first axial bore with the rear chamber, said housing having a third passage connecting the first axial bore with the atmosphere; second hub means connected to said first hub means for transmitting the operational force to said brake actuator from said wall means, said sEcond hub means having a second housing with a second axial bore coaxial to said first axial bore, said second housing having an entrance port through which air above atmospheric pressure is communicated to the second bore; first valve means located in said first axial bore for controlling the communication of vacuum through the first passage; second valve means located in said second axial bore for controlling the communication of air above atmospheric pressure from the second bore; plunger means located in said first and second axial bores for progressively operating the first and second valve means in response to said input force; and check valve means connected to the third passage in the first hub means for allowing air at atmospheric pressure to be communicated to said second passage when vacuum communication through the first passage is interrupted by movement of the first valve means and for preventing air above atmospheric pressure from entering the third passage when air above atmospheric pressure is presented to the second passage upon movement of the second valve means in response to movement of the plunger means.

Claim 3

Dependent Claim 63 words

In the servomotor, as recited in claim 1, wherein said first hub means includes: a shoulder located between the second passage and the second hub means; an annular ridge located adjacent the first passage, said first valve means engaging said annular ridge to prevent vacuum communication through said first passage; and an annular rib adjacent the forward end of the first axial bore.

Claim 4

Dependent Claim 86 words

In the servomotor, as recited in claim 2, wherein said plunger means includes: a cylindrical body with an annular atmospheric seat for engaging said first valve means to interrupt communication of air at atmospheric pressure through the third passage; an annular stop for engaging the shoulder on the first hub means to limit the movement with respect thereto; and a guide surface for engaging the second hub means to maintain the plunger means in axial alignment with the first axial bore of the first hub means.

Claim 5

Dependent Claim 101 words

In the servomotor, as recited in claim 3, wherein said first valve means includes: a tubular member located in said first axial bore having a first end fixed in said first hub means and a second end free to move axially within said bore; first resilient means connected to said plunger means for holding said annular stop against the shoulder; and second resilient means connected to said plunger means for holding said free end against said annular atmospheric seat with said annular stop against the shoulder and against the annular ridge upon movement of the annular stop away from the shoulder.

Claim 6

Dependent Claim 87 words

In the servomotor, as recited in claim 4, wherein said second valve means includes: sleeve means concentric to said second axial bore having a first end with an outwardly projecting annular surface and a second end with an inwardly projecting surface; and a third resilient means connected to said second hub means for urging the outwardly projecting annular surface of the sleeve means into engagement with an annular rib to seal the air above atmospheric pressure present at said air entrance port from entering the first bore.

Claim 7

Dependent Claim 47 words

In the servomotor, as recited in claim 5, wherein said annular stop on the plunger means upon movement thereof in response to an input force will engage the inwardly projecting surface of said sleeve means to allow communication between the entrance port and the first axial bore.

Claim 8

Dependent Claim 58 words

In the servomotor, as recited in claim 6, wherein said plunger means further includes: bumper means located adjacent the annular stop for absorbing a portion of the input force transmitted through the plunger means to allow air at atmospheric pressure to initially be presented to the rear chamber through the second passage upon movement of the plunger means.

Claim 9

Dependent Claim 65 words

In the servomotor, as recited in claim 7, wherein said plunger means includes: a push rod having a spherical head For moving said cylindrical body in response to said input force; and retainer means located on said push rod for moving a filter means along with the plunger means and for preventing the filter means from interferring with the operation of the check valve means.

Claim 10

Dependent Claim 90 words

In the servomotor, as recited in claim 8, wherein said check valve means includes: boot means having a first peripheral bead located in a groove on the periphery of the first hub means and a second bead secured to said push rod, said boot having a skirt which axially extends into the first bore past the third passage, said skirt creating a flapper moving away from the third passage in response to air at atmospheric pressure flowing therethrough and toward the third passage in response to air above atmospheric pressure.

Claim 11

Dependent Claim 89 words

In the servomotor, as recited in claim 9, wherein said wall means includes: a backing plate having a tubular surface along the inner periphery thereof, said tubular surface being located on a guide surface on the first hub means, said tubular surface transmitting the operational force derived from the pressure differential to the second hub means; and a diaphragm having an inner periphery held against an annular peripheral projection on the first hub means by the backing plate to provide a sealed separation between the front and rear chambers.

Claim 12

Dependent Claim 35 words

In the servomotor, as recited in claim 10, wherein said backing plate includes: an annular ring extending inwardly therefrom into engagement with the diaphragm to provide a radial sealing force with the first hub means.

Claim 13

Dependent Claim 101 words

In the servomotor, as recited in claim 8, wherein said check valve means includes: boot means having a first peripheral bead located in a groove on the periphery of the first hub means and a second bead secured to said push rod, said boot having a skirt which axially extends into the first bore past the third passage, said skirt having a series of axial slits adjacent the third passage to create a flapper moving away from the third passage in response to air at atmospheric pressure flowing therethrough and toward the third passage in response to air above atmospheric pressure.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1978-04-28	1978-10-28	1979-04-29	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1982-04-28	1982-10-28	1983-04-29	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1986-04-28	1986-10-28	1987-04-29	$7700.00	Window Closed / Lapsed

Dual valve operated pressure differential servomotor

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