Information
-
Patent Grant
-
6345566
-
Patent Number
6,345,566
-
Date Filed
Thursday, July 20, 200024 years ago
-
Date Issued
Tuesday, February 12, 200223 years ago
-
Inventors
-
Original Assignees
-
Examiners
- Look; Edward K.
- Lazo; Thomas E
Agents
-
CPC
-
US Classifications
Field of Search
US
- 060 534
- 092 5 R
- 200 6189
-
International Classifications
-
Abstract
A master cylinder assembly for controlling a motor vehicle clutch including switches for controlling functions such as enabling the starter motor, disabling the cruise control, or signaling the engine computer. The assembly includes an annular seal disposed in an internal groove in the wall of the cylinder sealingly engaging the piston of the cylinder and dividing the cylinder into a pressurized chamber on one side of the seal and an unpressurized chamber open to atmosphere on the other side of the seal. The plurality of axially spaced pairs of contacts are provided on the inner wall of the cylinder in the unpressurized chamber for coaction with an annular contact carried by a flange structure defined by the piston so that as the piston moves axially within the cylinder in response to depression of the clutch the annular contact on the piston successively closes circuits associated with the successive spaced pairs of contacts on the inner wall of the cylinder whereby to successively enable or disable motor vehicle control devices associated with the pairs of cylinder contacts.
Description
BACKGROUND OF THE INVENTION
This invention relates to hydraulic master cylinder assemblies and more particularly to a hydraulic master cylinder assembly incorporating switching functions.
It has become general practice in the automobile industry to interlock the operation of the engine starter motor with other controls of the motor vehicle such that the starter motor is rendered inoperative unless the transmission is in neutral or park in motor vehicles provided with an automatic transmission or, in motor vehicles provided with a foot operated clutch and a manually operated gear shift transmission, unless the transmission is in neutral and/or the clutch pedal is fully depressed to fully release the clutch. In addition, it is convenient in a motor vehicle provided with a cruise control and a mechanical clutch to shut off the operation of the cruise control upon, for example, downshifting which in turn requires release of the clutch. Specifically, it is necessary that the cruise control be disconnected even before the clutch is fully released to enable the driver to cut out the cruise control by a slight foot tap on the clutch pedal. It is also desirable, upon clutch disengagement, to generate a signal for transmission to the engine computer indicating that the torque path is going to be disengaged so that the computer may take appropriate action such as shutting down the fuel injection or reducing the fuel injection.
Many arrangements have been provided for providing switching functions in association with the master cylinder assembly to accomplish the various desired switching operations as the clutch pedal is depressed. Examples of such switches are shown for example in U.S. Pat. Nos. 4,878,041; 4,719,444; 4,742,193; 4,649,238; and 5,343,005. The switch devices shown in these prior art patents are all of the type in which the switch mounts on the push rod of the master cylinder assembly and in which the switch includes a plurality of axially spaced switches which can be sequentially actuated in response to depression of the clutch to generate a sequential series of control signals with respect to cruise control, starter interlock, fuel injection control, etc. Whereas these prior art switches have proven to be generally satisfactory, generating the required control signals in response to depression of the clutch, the use of a separate switch module on the push rod of the master cylinder adds significantly to the overall cost and complexity of the master cylinder assembly and the sequential arrangement of the various switches along the length of the switch module results in a relatively long switch assembly which is incapatible with the relatively short push rods that are found in many present day motor vehicles.
SUMMARY OF THE INVENTION
This invention is directed to the provision of an improved switching arrangement for a master cylinder assembly.
More specifically, this invention is directed to the provision of a master cylinder assembly in which the switching functions are provided integral with the master cylinder assembly.
The invention is applicable to a pressure cylinder apparatus of the type including a hydraulic cylinder structure having a cylindrical wall defining a generally closed left end and a generally open right end; a piston movable axially within the hollow of the cylinder structure; a seal structure between the piston and the cylinder structure defining a fluid pressure chamber within the cylinder on the left side of the piston and an unpressurized chamber on the right side of the piston; a fluid pressure fitting communicating with the pressure chamber for connection to a fluid pressure conduit communicating with a coacting fluid pressure device; and a piston rod extending through the open end of the cylinder and into the unpressurized chamber for connection to the right side of the piston.
According to the invention, a contact is carried by the piston at a location on the piston to the right of the seal structure and within the unpressurized chamber; a contact is disposed at an interior surface of the cylinder within the unpressurized chamber for selective coaction with the piston contact in response to axial movement of the piston in the hollow of the cylinder; and an electrical lead is connected to one of the contacts and extends to a location external to the cylinder for providing an electrical control signal generated in response to closing of the cylinder contact by the piston contact. This switching arrangement provides a switching function required in association with a typical pressure cylinder apparatus while reducing the overall cost and complexity of the total pressure cylinder apparatus and minimizing the overall size of the total pressure cylinder apparatus.
According to a further feature of the invention, a plurality of axially spaced contacts are disposed at the interior surface of the cylinder within the unpressurized chamber for selective coaction with the piston contact in response to axial movement of the piston in the hollow of the cylinder, and a plurality of electrical leads are connected to the respective cylinder contacts and extend to locations external to the cylinder for providing respective electrical control signals generated in response to selective closing of the cylinder contacts by the piston contact. This switching arrangement provides all of the switching functions required in association with a typical pressure cylinder apparatus while reducing the overall cost and complexity of the total pressure cylinder apparatus and minimizing the overall size of the total pressure cylinder apparatus.
According to a further feature of the invention, the seal structure comprises an annular elastomeric seal positioned in an annular groove provided in the interior surface of the cylinder and arranged for wiping engagement with an exterior surface of the piston as the piston moves axially in the cylinder. This arrangement maximizes the length of the unpressurized chamber in which the cylinder contacts are disposed.
According to a further feature of the invention, the cylinder is a compound structure constituted by a left cylinder structure defining the pressure chamber and a right cylinder structure coupled to the left cylinder structure and carrying the plurality of axially spaced cylinder contacts. This arrangement allows the switching functions of the apparatus to be embodied in a separate module for inventory and quality control purposes.
According to a further feature of the invention, the right cylinder structure is a compound structure constituted by a cartridge and a right cylinder member having a cylindrical wall having an open right end and including an axially extending slot opening into the hollow interior of the right cylinder and opening at the right end of the right cylinder; the cartridge is sized to fit in the slot; the axially spaced cylinder contacts are provided on an inner surface of the cartridge; and the electrical leads are carried by the cartridge. This specific arrangement allows the switching functions of the apparatus to be totally isolated from the remainder of the apparatus for inventory and quality control purposes.
Other objects, advantages and applications of the present invention will become apparent to those skilled in the art when the following description of the best mode contemplated for practicing the invention is read in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
The description herein makes reference to the accompanying drawings wherein like reference numerals refer to like parts throughout the several views, and wherein:
FIG. 1
is a partial schematic view of a motor vehicle incorporating a master cylinder apparatus according to the invention;
FIG. 2
is a cross-sectional view of the master cylinder apparatus;
FIG. 3
is a cross-sectional view taken on line
3
—
3
of
FIG. 2
;
FIG. 4
is a perspective exploded view of the master cylinder apparatus; and
FIG. 5
is a bottom detail view of a switch cartridge embodied in the master cylinder apparatus.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The invention master cylinder apparatus
10
is seen in
FIG. 1
in association with a motor vehicle of the type including a firewall
12
, a clutch pedal
14
, a slave cylinder
16
, and a clutch
18
. The master cylinder
10
is fixedly secured to firewall
12
in known manner and clutch pedal
14
is pivotally secured to the free end of the push rod
20
of the master cylinder so that depression of the clutch pedal
14
by a vehicle operator transmits pressurized hydraulic fluid through a conduit
22
to slave cylinder
16
which operates a release lever
24
which acts upon a clutch release bearing
26
to disengage the clutch
18
in known manner.
Master cylinder
10
(
FIGS. 2 and 3
) includes a cylinder structure
28
, a seal assembly
30
, a cartridge
32
, push rod
20
, a piston assembly
34
, and a reservoir
36
.
The designations left and right as hereinafter employed are with respect to FIG.
2
and the designations forwardly and rearwardly as hereinafter employed designate leftward and rightward movement, respectively, as viewed in FIG.
2
.
Cylinder structure
28
includes a left cylinder structure
38
and a right cylinder structure
40
. The cylinder structures are shown in their coupled relationship in FIG.
2
and in an exploded relationship in FIG.
3
.
Left cylinder structure
38
includes a left relatively small diameter portion
38
a
and a right relatively large diameter portion
38
b
. Left portion
38
a
defines a bore
38
c
and a fluid pressure outlet
38
d
. Right portion
38
b
defines a bore
38
e
, a counter bore
38
f
, a conical bore
38
g
interconnecting bores
38
e
and
38
f
, a further counter bore
38
h
, a conical bore
38
i
interconnecting bores
38
f
and
38
h
, an external mounting flange
38
j
, a reservoir fitting
38
k
, and an annular shoulder
38
l
interconnecting bores
38
c
and
38
e.
Right cylinder member
40
includes a main body tubular portion
40
a
including an axially extending slot
40
b
opening at the right face
40
c
of the main body tubular portion, an enlarged diameter flange portion
40
d
joined to main body portion
40
a
by an annular shoulder
40
e
, and circumferentially spaced finger portions
40
f
extending rearwardly from flange portion
40
e
in radially spaced relation to main body portion
40
a
. The left portion of flange portion
40
d
has an angled exterior surface
40
g
defining an annular interior groove
40
h
. Flange portion
40
d
further defines an annular external groove
40
i
for receipt of an elastomeric O-ring
42
. Right cylinder member
40
is fitted telescopically into left cylinder member
38
with flange portion
40
d
slidably received in bore
38
f
, O-ring
42
sealingly engaging bore
38
f
, and nubs
40
n
carried by the free ends
40
j
of fingers
40
f
snappingly received in respective arcuate slots
38
m
in portion
38
b
to preclude inadvertent withdrawal of part
40
from part
38
.
Seal assembly
30
includes a primary annular elastomeric seal
44
, a secondary annular elastomeric seal
46
, and an annular spacer
48
. Primary seal
44
is received in an annular groove
38
m
defined between shoulder
38
l
and bore
38
e
, secondary seal
46
is received in annular groove
40
h
, and annular spacer
48
is positioned between the primary and secondary seals proximate conical bore
38
g.
Cartridge
32
(see also
FIG. 4
) includes a main body portion
32
a
formed of a suitable insulative material and a plurality of conductors or leads
50
embedded in main body portion
32
a
and formed of a suitable conductive material. Main body portion
32
a
is sized to fit in slot
40
b
and has an arcuate cross-sectional configuration conforming to the radius of cylinder main body portion
40
a
so as to, when fitted into slot
40
b
, form a continuation of the arcuate circumferential curve of main body portion
40
a
. When fitted into slot
40
b
the inner arcuate surface
32
b
of the main body portion is flush with bore
40
k
of cylinder main body portion
40
a
, the left end
30
c
of the main body portion is seated against the end
40
l
of slot
40
b
and telescopically positioned in cylinder bore
38
h
, and the main body portion is positioned circumferentially between circumferentially spaced finger portions
40
f
. Leads
50
extend axially through main body portion
32
a
and define terminal ends
50
a
for connection to external leads and contacts
50
b
positioned in exposed relation flush with the inner surface
32
b
of the main body portion.
A plurality of pairs of leads are provided. For example, and as shown, two pairs of leads are provided with the first pair of leads terminating in a pair of circumferentially spaced contacts
50
c
and the second pair of leads terminating in a pair of circumferentially spaced contacts
50
d
spaced axially from contacts
50
c.
Push rod
20
includes a main body shaft portion
20
a
, a swivel portion
20
b
for pivotal connection to clutch pedal
14
, and a spherical ball end portion
20
c.
Piston assembly
34
includes a piston member
52
, a pair of insert halves
54
, and a piston contact
56
.
Piston member
52
is formed of a suitable sheet metal material and includes a main body outer shell portion
52
a
, an inner tubular portion
52
b
positioned concentrically within the left end of outer shell portion
52
a
and joined to the left end of shell portion
52
a
by annular shoulder
52
c
, and an inwardly directed flange portion
52
d
at the right end of outer shell portion
52
a
. Piston
52
is sized to fit slidably within bore
40
k
and to sealingly engage at its left end with the inner lip seal portions of primary seal
44
and secondary seal
46
.
Each insert half
54
is formed of a suitable plastic material in a suitable molding operation and includes a right end flange portion
54
a
, a hemispherical portion
54
b
adjoining flange portion
54
a
, and a main body portion
54
c
extending rearwardly from hemispherical portion
54
b
and defined by a plurality of circumferentially spaced ribs
54
d
and a flat inner face
54
e.
In the assembled relation of the piston assembly, insert halves
54
are received within piston member
52
with nubs
54
e
on the ribs
54
d
engaging the inner piston member walls, the left end
54
f
of the insert halves bearing against the blind end
52
e
of the inner tubular portion
52
b
of the piston member, and the flange
52
d
of the piston member crimped over the ends
54
g
of the ribs
54
d
to firmly lock the piston member over the main body portions of the insert halves. The spherical portions
54
b
and the flange portions
54
a
of the insert halves project forwardly out of the piston member to define a spherical cavity
54
h
and an annular flange constituted by the fitted together flange halves
54
a
of the upper and lower insert halves.
Contact
56
has an annular configuration, is formed of a suitable conductive material, and is fitted over flanges
54
a
in crimping fashion so as to be fixedly mounted on flanges
54
a.
In the assembled relation of the piston assembly and the push rod, the ball end
20
c
of the push rod is received in spherical cavity
54
h
and the main body
20
a
of the push rod extends through the open right-hand end of right cylinder member
40
.
In the assembled relation of the master cylinder, it will be seen that the piston assembly and the seals coact to define a hydraulic fluid pressure chamber within the bore
38
c
on the left side of the piston and a dry unpressurized atmospheric chamber within the bore
40
k
on the right side of the piston, and it will further be seen that the contact pairs
50
c
/
50
d
as well as the annular contact
56
are positioned in the dry, unpressurized chamber defined within the bore
40
k
. It further will be understood that fitting
38
k
is connected by a conduit, such as conduit
60
seen in
FIG. 1
, to an external hydraulic fluid reservoir
62
whereby to deliver hydraulic fluid to the cylinder apparatus and it will be further understood that seal assembly
30
acts in known manner to allow the delivery of hydraulic fluid to the pressure chamber within the bore
38
c
on the left side of the piston assembly while precluding delivery of hydraulic fluid to the unpressurized chamber within the bore
40
k.
In operation, the clutch pedal is depressed to move the piston assembly to the left to eject hydraulic fluid under pressure through fitting
38
d
for delivery to a coacting fluid pressure device such as the slave cylinder
16
controlling the clutch
18
and, upon release of the clutch pedal, the piston assembly is returned to the right under the action of a return spring
58
with hydraulic fluid flowing from the reservoir through the conduit
60
and fitting
38
k
and past the collapsed primary seal
44
to fill in the chamber
38
c
behind the retreating piston assembly. The rightward, return movement of the piston is defined by engagement of contact
56
with an annular lip
40
m
on the right end of cylinder member
40
and a coacting annular lip
32
d
on the right end of cartridge
32
.
As the piston assembly moves forwardly within the cylinder structure, annular contact
56
first engages the contacts
50
c
to electrically span the circumferential space between the contacts and complete a circuit through the two leads
50
defining the spaced contacts
50
c
whereby to transmit a control signal to an associated cruise control device to disengage the cruise control whereafter, with further leftward movement of the piston assembly in response to further depression of the clutch pedal, contact
56
electrically spans the circumferential space between the contacts
50
d
to complete an electrical circuit through the two leads
50
defining the contacts
50
d
and thereby generate an electrical control signal for transmittal, for example, to the engine starter motor to enable starting of the engine and/or to the engine computer for appropriate action consistent with disengagement of the engine torque path.
The invention will be seen to provide a master cylinder assembly in which the switching functions are provided integral with the master cylinder assembly whereby to minimize the overall cost and complexity of the master cylinder and switch assembly and whereby to eliminate the space problems associated with the separate switch assembly positioned on the push rod of the master cylinder assembly.
While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiment but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims, which scope is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures as is permitted under the law.
Claims
- 1. A pressure cylinder apparatus comprising:a hydraulic cylinder structure having a cylindrical wall defining a generally closed left end and a generally open right end; a piston movable axially within the hollow of the cylinder structure; a seal structure between the piston and the cylinder structure defining a fluid pressure chamber within the cylinder structure on the left side of the piston and an unpressurized chamber on the right side of the piston; a fluid pressure fitting communicating with the pressure chamber for connection to a fluid pressure conduit communicating with a coacting fluid pressure device; a piston rod extending through the open end of the cylinder structure and into the unpressurized chamber for connection to the right side of the piston; a piston contact carried by and fixedly secured to the piston at a location on the piston to the right of the seal structure and within the unpressurized chamber; a cylinder contact disposed at an interior surface of the cylinder structure within the unpressurized chamber for coaction with the piston contact in response to axial movement of the piston in the hollow of the cylinder structure; and an electrical lead connected to one of the piston and cylinder contacts and extending to a location external to the cylinder apparatus for providing an electrical control signal generated in response to engagement of the cylinder contact with the piston contact.
- 2. A pressure cylinder apparatus according to claim 1 wherein the seal structure is carried by the cylinder structure.
- 3. A pressure cylinder apparatus according to claim 2 wherein the seal structure comprises an annular elastomeric seal positioned in an annular groove provided in the interior surface of the cylinder structure and arranged for wiping engagement with an exterior surface of the piston as the piston moves axially in the cylinder structure.
- 4. A pressure cylinder apparatus according to claim 1 wherein the cylinder structure is a compound structure constituted by a left cylinder structure defining the pressure chamber and a right cylinder structure coupled to the left cylinder structure and carrying the cylinder contact.
- 5. A pressure cylinder apparatus comprising:a hydraulic cylinder structure having a cylindrical wall defining a generally closed left end and a generally open right end; a piston movable axially within the hollow of the cylinder structure; a seal structure between the piston and the cylinder structure defining a fluid pressure chamber within the cylinder structure on the left side of the piston and an unpressurized chamber on the right side of the piston; a fluid pressure fitting communicating with the pressure chamber for connection to a fluid pressure conduit communicating with a coacting fluid pressure device; a piston rod extending through the open end of the cylinder structure and into the unpressurized chamber for connection to the right side of the piston; a piston contact carried by the piston at a location on the piston to the right of the seal structure and within the unpressurized chamber; a cylinder contact disposed at an interior surface of the cylinder structure within the unpressurized chamber for coaction with the piston contact in response to axial movement of the piston in the hollow of the cylinder structure; and an electrical lead connected to one of the piston and cylinder contacts and extending to a location external to the cylinder apparatus for providing an electrical control signal generated in response to engagement of the cylinder contact with the piston contact; the cylinder structure comprising a compound structure constituted by a left cylinder structure defining the pressure chamber and a right cylinder structure coupled to the left cylinder structure and carrying the cylinder contact; the right cylinder structure comprising a compound structure constituted by a cartridge and a right cylinder member having a cylindrical wall having an open right end and including a axially extending slot opening into the hollow interior of the right cylinder member and opening at the right end of the right cylinder member; the cartridge being sized to fit in the slot; the cylinder contact being provided on an inner surface of the cartridge; and the electrical lead being carried by the cartridge and connecting to the cylinder contact.
- 6. A pressure cylinder apparatus comprising:a hydraulic cylinder structure having a cylindrical wall defining a generally closed left end and a generally open right end; a piston movable axially within the hollow of the cylinder structure; a seal structure between the piston and the cylinder structure defining a fluid pressure chamber within the cylinder structure on the left side of the piston and an unpressurized chamber on the right side of the piston; a fluid pressure fitting communicating with the pressure chamber for connection to a fluid pressure conduit communicating with a coacting fluid pressure device; a piston rod extending through the open end of the cylinder structure and into the unpressurized chamber for connection to the right side of the piston; a piston contact carried by an fixedly secured to the piston at a location on the piston to the right of the seal structure and within the unpressurized chamber; a plurality of axially spaced cylinder contacts disposed at an interior surface of the cylinder structure within the unpressurized chamber for selective coaction with the piston contact in response to axial movement of the piston in the hollow of the cylinder structure; and a plurality of electrical leads connected to the respective cylinder contacts and extending to locations external to the cylinder structure for providing respective electrical control signals generated in response to selective closing of the cylinder contacts by the piston contact.
- 7. A pressure cylinder apparatus according to claim 6 wherein the seal structure is carried by the cylinder structure.
- 8. A pressure cylinder apparatus according to claim 7 wherein the seal structure comprises an annular elastomeric seal positioned in an annular groove provided in the interior surface of the cylinder structure and arranged for wiping engagement with an exterior surface of the piston as the piston moves axially in the cylinder.
- 9. A pressure cylinder apparatus according to claim 6 wherein the cylinder structure is a compound structure constituted by a left cylinder structure defining the pressure chamber and a right cylinder structure coupled to the left cylinder structure and carrying the plurality of axially spaced cylinder contacts.
- 10. A pressure cylinder apparatus comprising:a hydraulic cylinder structure having a cylindrical wall defining a generally closed left end and a generally open right end; a piston movable axially within the hollow of the cylinder structure; a seal structure between the piston and the cylinder structure defining a fluid pressure chamber within the cylinder structure on the left side of the piston and an unpressurized chamber on the right side of the piston; a fluid pressure fitting communicating with the pressure chamber for connection to a fluid pressure conduit communicating with a coacting fluid pressure device; a piston rod extending through the open end of the cylinder structure and into the unpressurized chamber for connection to the right side of the piston; a piston contact carried by the piston at a location on the piston to the right of the seal structure and within the unpressurized chamber; a plurality of axially spaced cylinder contacts disposed at an interior surface of the cylinder structure within the unpressurized chamber for selective coaction with the piston contact in response to axial movement of the piston in the hollow of the cylinder structure; and a plurality of electrical leads connected to the respective cylinder contacts and extending to locations external to the cylinder structure for providing respective electrical control signals generated in response to selective closing of the cylinder contacts by the piston contact; the cylinder structure comprising a compound structure constituted by a left cylinder structure defining the pressure chamber and a right cylinder structure coupled to the left cylinder structure and carrying the plurality of axially spaced cylinder contacts; the right cylinder structure comprising a compound structure constituted by a cartridge and a right cylinder member having a cylindrical wall having an open right end and including an axially extending slot opening into the hollow interior of the right cylinder member and opening and the right end of the right cylinder member; the cartridge being sized to fit in the slot; the axially spaced cylinder contacts being provided on a interior surface of the cartridge; and the electrical leads being carried by the cartridge.
- 11. A pressure cylinder apparatus comprising:a hydraulic cylinder structure having a cylindrical wall defining a generally closed left end, a generally open right end, and an axially extending slot opening into the hollow interior of the cylinder proximate the right cylinder end; a piston movable axially within the hollow of the cylinder structure; a seal structure between the piston and the cylinder structure defining a fluid pressure chamber within the cylinder structure on the left side of the piston and an unpressurized chamber on the right side of the piston; a fluid pressure fitting communicating with the pressure chamber for connection to a fluid pressure conduit communicating with a coacting fluid pressure device; a piston rod extending through the open right end of the cylinder structure and into the unpressurized chamber for connection to the right side of the piston; a contact carried by the piston at a location on the piston to the right of the seal structure and within the unpressurized chamber; and a cartridge assembly including a cartridge body received in the slot and a plurality of leads extending through the cartridge body and terminating in a plurality of axially spaced contacts disposed at an interior surface of the cartridge body confronting the hollow of the cylinder structure within the unpressurized chamber for selective coaction with the piston contact.
- 12. A pressure cylinder apparatus according to claim 11 wherein the seal structure is carried by the cylinder structure.
- 13. A pressure cylinder apparatus according to claim 12 wherein the seal structure comprises an annular elastomeric seal positioned in an annular groove provided in the interior surface of the cylinder structure and arranged for wiping engagement with an exterior surface of the piston as the piston moves axially in the cylinder structure.
- 14. A pressure cylinder apparatus according to claim 11 wherein:the cylinder structure is a compound structure constituted by a left cylinder structure defining the pressure chamber and a right cylinder structure coupled to the left cylinder structure; the cartridge forms a part of the right cylinder structure; and the right cylinder structure further includes a right cylinder member defining the slot in which the cartridge is received.
- 15. A pressure cylinder apparatus comprising:a hydraulic cylinder assembly including a left cylinder member, having a generally closed left end and defining a rightwardly opening socket at its right end, and a right cylinder member telescopically received at a left end thereof in the socket of the left cylinder member, coacting at its left end with the left cylinder member to define an annular inwardly opening groove, and defining a bore; an annular seal received in the annular groove; a piston slidably received in the right cylinder member bore and wipingly engaging the annular seal; an electric contact carried by and fixedly secured to the piston proximate a right end of the piston; a plurality of axially spaced contacts carried by the right cylinder member and disposed in confronting relation to the right cylinder member bore for selective coaction with the piston contact in response to axial movement of the piston in the right cylinder member bore; and a plurality of electrical leads connected to the respective cylinder contacts and extending to locations external to the right cylinder member for providing respective electrical control signals generated in response to selective closing of the cylinder contacts by the piston contact.
- 16. A pressure cylinder apparatus comprising:a hydraulic cylinder assembly including a left cylinder member, having a generally closed left end and defining a rightwardly opening socket at its right end, and a right cylinder member telescopically received at a left end thereof in the socket of the left cylinder member, coacting at its left end with the left cylinder member to define an annular inwardly opening groove, and defining a bore; an annular seal received in the annular groove; a piston slidably received in the right cylinder member bore and wipingly engaging the annular seal; an electric contact carried by the piston proximate a right end of the piston; a plurality of axially spaced contacts carried by the right cylinder member and disposed in confronting relation to the right cylinder member bore for selective coaction with the piston contact in response to axial movement of the piston in the right cylinder member bore; and a plurality of electrical leads connected to the respective cylinder contacts and extending to locations external to the right cylinder member for providing respective electrical control signals generated in response to selective closing of the cylinder contacts by the piston contact; the right cylinder member defining an axially extending slot opening at a right end of the right cylinder member; and the axially spaced contacts and electrical leads being carried by a cartridge fitted in the slot of the right cylinder member.
- 17. A pressure cylinder apparatus comprising a hydraulic cylinder structure having a cylindrical wall defining a generally closed left end and a generally open right end; a piston movable axially within the hollow of the cylinder structure; a seal structure between the piston and the cylinder structure defining a fluid pressure chamber within the cylinder structure on the left side of the piston and an unpressurized chamber on the right side of the piston; a fluid pressure fitting communicating with the pressure chamber for connection to a fluid pressure conduit communicating with a coacting fluid pressure device; and a piston rod extending through the open end of the cylinder structure and into the unpressurized chamber for connection to the right side of the piston; characterized in that:the apparatus includes a piston contact carried by the piston at a location on the piston to the right of the seal structure and within the unpressurized chamber; a plurality of axially spaced cylinder contacts are disposed at an interior surface of the cylinder structure within the unpressurized chamber for selective coaction with the piston contact in response to axial movement of the piston in the hollow of the cylinder structure; and a plurality of electrical leads are connected to the respective cylinder contacts and extend to locations external to the cylinder structure for providing respective electrical control signals generated in response to selective closing of the cylinder contacts by the piston contact; the cylinder structure comprising a compound structure constituted by a left cylinder structure defining the pressure chamber and a right cylinder structure coupled to the left cylinder structure and carrying a plurality of axially spaced cylinder contacts; the right cylinder structure comprising a compound structure constituted by a cartridge and a right cylinder member having a cylindrical wall having an open right end and including an axially extending slot opening into the hollow interior of the right cylinder member and opening up the right end of the right cylinder member; the cartridge being sized to fit in the slot; the axially spaced cylinder contacts being provided on an inner surface of the cartridge; the electric leads being carried by the cartridge; the pressure cylinder apparatus comprising a hydraulic master cylinder assembly for transmitting pressurized fluid to a slave cylinder for controlling a motor vehicle function.
- 18. A pressure cylinder apparatus according to claim 17 wherein the motor vehicle function comprises engagement and disengagement of a motor vehicle clutch.
US Referenced Citations (12)
Number |
Name |
Date |
Kind |
3015001 |
Woofter |
Dec 1961 |
A |
4239947 |
Breitung et al. |
Dec 1980 |
A |
4354069 |
Ragen |
Oct 1982 |
A |
4621565 |
Leigh-Monstevens |
Nov 1986 |
A |
4649238 |
Beck et al. |
Mar 1987 |
A |
4719444 |
Leigh-Monstevens et al. |
Jan 1988 |
A |
4742193 |
Kassin et al. |
May 1988 |
A |
4878041 |
Leigh-Monstevens et al. |
Oct 1989 |
A |
4911276 |
Leigh-Monstevens et al. |
Mar 1990 |
A |
5343005 |
Salzmann |
Aug 1994 |
A |
6000516 |
Teichert et al. |
Dec 1999 |
A |
6250203 |
Mischler et al. |
Jun 2001 |
B1 |