Information
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Patent Grant
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6820534
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Patent Number
6,820,534
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Date Filed
Monday, March 8, 200420 years ago
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Date Issued
Tuesday, November 23, 200420 years ago
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Inventors
-
-
Examiners
Agents
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CPC
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US Classifications
Field of Search
-
International Classifications
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Abstract
A piston chamber assembly has a chamber and a piston slideably received in the chamber. The piston has a first side and a second side. A first inlet communicates air into the chamber on the first side while a second inlet communicates air into the chamber on the second side. An actuator is moveable between a first position and a second position. The actuator selectively opens and closes the first inlet and the second inlet. In the first position, the actuator closes the second inlet and opens a first inlet while in the second position the actuator opens the second inlet and closes the first inlet. The actuator is coupled to the piston, which drives the actuator between the first position and the second position.
Description
BACKGROUND OF THE INVENTION
This invention relates to a cylinder and piston assembly.
Automotive manufacturers generally test vehicle components, such as a vehicle door, by simulating the operating conditions of the vehicle component. For example, to test the functioning of a door, the manufacturer may repeatedly open and close the door to test wear and tear. Frequently, this action is performed by a piston and cylinder, which opens and closes the door.
The cylinder is connected to an air compressor while the piston is connected by a rod to the test component. Air to the piston and cylinder is controlled by a computer. The computer directs air from the compressor to one side of the piston to move the piston and rod in one direction. When the piston has moved to one side of the cylinder, the computer then directs air to the opposite side of the piston to thereby move the piston and rod in the other direction. This cycle is repeated.
The task performed by the piston and cylinder is simple. However, a computer is still used to control the assembly's operation. The computer adds significant expense to the testing of the component. A need therefore exists for a piston and cylinder that cycles without a computer.
SUMMARY OF THE INVENTION
The invention comprises a piston and cylinder assembly. Like existing designs, the invention has a piston that is slideably received in a chamber of the cylinder. On one side of the piston is one air inlet while on the other side of the piston is a second air inlet. In contrast to conventional assemblies, the invention has an actuator within the chamber that is moveable between a first position and a second position. In the first position, the actuator opens the first inlet and closes the second. In the second position, the actuator closes the first inlet and opens the second.
The actuator is coupled to the piston, which drives the actuator between the first position and the second position. Accordingly, air entering the cylinder on the first side of the piston expands the piston and thereby moves the actuator to close the first inlet and open the second inlet. Air in the second inlet is then allowed to expand the piston and move the actuator so as to close the second inlet and again permit air through the first inlet. In this way, the inventive assembly cycles without the need of a computer.
The actuator may comprise a body in the chamber of the cylinder. The body may move in one direction towards the first position and in another direction towards the second position. The piston is arranged to impart its momentum to the body in either direction. In this way, the body moves between the first position and the second position.
The actuator may further have a first portion and a second portion. The piston may be supported to move between the first portion and the second portion alternatingly in one direction and the other direction. The actuator thereby imparts its momentum to either the first portion or the second portion. The first portion may close the first inlet in the second position while the second portion closes the second inlet in the first position.
The invention further has a retaining feature that holds the actuator in either the first position or the second position until a predetermined amount of momentum is received by the actuator. This feature may comprise a magnet. In this way, the actuator stays in its position until sufficient momentum is imparted by the piston. This feature thereby avoids movement of the actuator with the piston until sufficient momentum has been received by the actuator to move between positions.
Another version of the invention uses a different actuator. The actuator has a member that is rotated by the piston between a first position and a second position. The rotating actuator has a first portion and a second portion. The first portion has a first opening that permits air from the first inlet into the chamber while the second portion has a second opening that permits air from the second inlet into the chamber. When the piston has reached a certain position on the member, the member rotates to close the first inlet and open the second inlet. The member is then subsequently rotated by the piston to close the second inlet when the first inlet is opened.
The piston slides relative to this rotating actuator. The actuator has a cam that is selectively in contact with the piston. The action of the piston on the cam rotates the actuator between the first position and the second position. The piston may further be mounted to a groove on the actuator. The cam may be part of the groove.
Both features permit the inventive assembly to cycle by itself. There is no need for a computer to control air flow into the piston chamber. The invention is therefore much cheaper to produce.
BRIEF DESCRIPTION OF THE DRAWINGS
The various features and advantages of this invention will become apparent to those skilled in the art from the following detailed description of the currently preferred embodiment. The drawings that accompany the detailed description can be briefly described as follows:
FIG. 1
illustrates a cross-sectional view of the inventive assembly in the first position with the first inlet open and the second inlet closed.
FIG. 2
illustrates the assembly of
FIG. 1
in the second position with the second inlet open and the first inlet closed.
FIG. 3
illustrates a cross-sectional view of another version of the invention in the first position with the first inlet open and the second inlet closed.
FIG. 4
illustrates a cross-sectional view of the inventive assembly of
FIG. 3
at the point in which the actuator switches between the first position and the second position.
FIG. 5
illustrates the assembly of
FIGS. 3 and 4
in the second position with the second air inlet open and the first inlet closed.
FIG. 6
illustrates a view of the piston and actuator of FIG.
3
-
5
.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1
illustrates a cross-sectional view of an inventive piston chamber assembly
10
. Piston chamber assembly
10
has piston
18
and chamber
14
, defined by cylinder
12
. Piston
18
has first side
22
and second side
26
. On first side
22
of piston
18
, there is provided first inlet
30
that permits the passage of air from compressor
13
through line
17
onto first side
22
of piston
18
. In addition, piston chamber assembly
10
has second inlet
34
, which permits air from compressor
13
through line
19
to pass onto second side
26
of piston
18
. Here, piston
18
is attached to rod
16
, which may be attached to a test piece.
In contrast to conventional designs, piston chamber assembly
10
has actuator
38
disposed within chamber
14
. Actuator
38
has body
50
, which has first portion
54
on first side of piston
18
and second portion
58
on second side
26
of piston
18
. First portion
54
and second portion
58
are slideably received within chamber
14
. In addition, first portion
54
and second portion
58
are connected by rods
21
so that they may slide together within chamber
14
.
Piston
18
is also slideably received on rods
21
between first portion
54
and second portion
58
. Piston
18
further has seal
20
, here an O-ring, that serves to wipe chamber
14
as well as to provide a seal between first side
22
and second side
26
of piston
18
. Piston chamber assembly
10
further has exhaust outlet
28
on first side
22
of piston
18
and exhaust outlet
29
on second side
26
of piston
18
. Exhaust outlet
29
is merely a gap between rod
16
and end portion
33
of cylinder
12
.
The operation of piston chamber assembly
10
will now be explained with reference to
FIGS. 1 and 2
.
FIG. 1
illustrates piston chamber assembly
10
with actuator
38
in first position
42
. As shown, first portion
54
is in a position to cover exhaust outlet
28
. Moreover, second portion
58
is in a position to cover second inlet
34
. Retaining feature
62
, here a magnetic plate, holds first portion
54
in first position
42
. First portion
54
and second portion
58
are both attractable by magnet of retaining feature
62
.
In first position
42
, air passes from compressor
13
through line
15
and splits into line
17
and line
19
. Because first inlet
30
is open to receive air on first side
22
of piston
18
and second inlet
34
is closed due to the position of second portion
58
in first position
42
, piston
18
expands in the direction of arrow B moving rod
16
in the same direction. Piston
18
develops momentum and impacts second portion
58
as shown in FIG.
2
. This collision between second portion
58
and piston
18
causes first portion
54
to become dislodged from retaining feature
62
and to move to second position
46
, where second portion
58
is held in place by the other retaining feature
62
.
In this second position
46
, actuator
38
now allows air to pass from line
19
through second inlet
34
onto second side
26
of piston
18
. Moreover, first inlet
30
is closed so that air from compressor
13
will not enter into chamber
14
on first side
22
of piston
18
. Exhaust
28
is also open to permit air on first side
22
to escape. Air passes through second inlet
34
to cause piston
18
and rod
16
to move in the direction of arrow A. Piston
18
then develops momentum and comes into contact with first portion
54
to thereby drive first portion
54
back to first position
42
shown in FIG.
1
. Piston chamber assembly
10
may cycle back and forth in manner indefinitely. It is preferable for piston
18
to be made of a material having a low coefficient of friction, preferably, DuPont's DERLIN™ ring material.
Piston chamber assembly
10
has adjuster
31
. Adjuster
31
comprises a set screw, which may be turned to move adjuster
31
in the direction of arrow A or B. Stroke adjuster
31
is threadedly received by first portion
54
and moves with first portion
54
. By turning the screw, adjuster
31
may adjust the position of piston
18
within chamber
10
relative to end portion
27
so as to prevent piston
18
from covering first inlet
30
in first position
42
.
FIGS. 3-5
illustrate another version of the inventive piston chamber assembly. Here, piston chamber assembly
100
comprises chamber
14
having piston
18
slideably received within chamber
14
. Piston
18
has first side
22
and second side
26
. In addition, piston
18
has seal
20
. Chamber
14
is provided with first inlet
30
and second inlet
34
as well as exhaust outlet
28
and exhaust outlet
29
. These features are identical to the features identified by the same numbers in FIG.
1
.
Unlike the previous version, actuator
66
here comprises a member rotatably mounted to end portion
27
and
33
of cylinder
12
. Actuator
66
may rotate in the direction of arrow R
1
or in the direction of arrow R
2
. Actuator
66
further has first portion
94
with first opening
98
and second portion
102
with second opening
106
. As shown in the figures, first opening
98
extends through actuator
66
in a transverse direction relative to second opening
106
. Accordingly, as shown in
FIG. 3
, when actuator
66
is in first position
70
, first opening
98
permits air to pass through first inlet
30
while second opening
106
is blocked by second portion
102
. Conversely, as shown in
FIG. 5
, if actuator
66
is rotated in the direction of arrow R
1
, first opening
98
is rotated so that it is no longer aligned with first inlet
30
. Consequently, first portion
94
blocks first inlet
30
while second opening
106
is now aligned with second inlet
34
to permit air to pass to second side
26
of piston
18
.
Like the previous version, piston
18
is mechanically linked to actuator
66
. As shown in
FIG. 6
, piston
18
is slideably received on actuator
66
. Piston
18
and actuator
66
are mechanically linked by pin
110
. Pin
110
extends from piston
18
into groove
90
. As shown in
FIG. 4
, groove
90
further has first cam
82
and second cam
86
, both of which define a portion of groove
90
.
The functioning of actuator
66
will now be explained with reference to
FIGS. 3-5
. As shown in
FIG. 3
, actuator
66
is in a position to permit air from line
17
to pass through first inlet
30
and through first opening
98
to first side
22
of piston
18
. Second opening
106
is blocked by second portion
102
. Air then expands piston
18
in the direction of arrow B. As shown in
FIG. 4
, pin
110
contacts first cam
18
as piston
18
slides to intermediate position
72
. This contact of pin
110
with cam
82
causes actuator
66
to rotate in the direction of arrow R
1
, here downward.
As shown in
FIG. 5
, when actuator
66
has rotated to second position
74
, actuator
66
now is in a position to block first inlet
30
because first opening
98
has rotated out of alignment with first inlet
30
. In addition, second opening
106
is now aligned with second inlet
34
to allow air to pass from line
19
to second side
26
of piston
18
. Piston
18
then expands in the direction of arrow A. Pin
110
moves along groove
90
so as to come in contact with cam
86
and thereby rotate actuator
66
in the upward direction of arrow R
2
. Consequently, actuator
66
then rotates back to first position
70
as shown in FIG.
3
.
The aforementioned description is exemplary rather that limiting. Many modifications and variations of the present invention are possible in light of the above teachings. The preferred embodiments of this invention have been disclosed. However, one of ordinary skill in the art would recognize that certain modifications would come within the scope of this invention. Hence, within the scope of the appended claims, the invention may be practiced otherwise than as specifically described. For this reason the following claims should be studied to determine the true scope and content of this invention.
Claims
- 1. A piston chamber assembly comprising:a chamber; a piston slideably received in said chamber, said piston having a first piston side and a second piston side; a first inlet for communicating a fluid into said chamber on said first piston side; a second inlet for communicating a fluid into said chamber on said second piston side; an actuator movable between a first position and a second position, said actuator for selectively opening said first inlet and closing said second inlet when in said first position and said actuator for selectively closing said first inlet and opening said second inlet when in said second position wherein said piston is coupled to drive said actuator between said first position and said second position; said actuator comprising a body in said chamber, said body selectively movable between a first direction towards said first position and a second direction towards said second position; said piston arranged to impart momentum to said actuator selectively between said first direction and said second direction, thereby moving said actuator between said first position and said second position; said actuator comprising a first portion and a second portion, said piston supported to move between said first portion and said second portion alternating in said first direction and said second direction to impart momentum to one of said first portion and said second portion; said first portion closing said first inlet in said second position and said second portion closing said second inlet in said first position; and a retaining feature for maintaining said actuator in one of said first position and said second position until a predetermined amount of momentum is received by said actuator.
- 2. The piston chamber assembly of claim 1 wherein said retaining feature comprises a magnet.
- 3. A piston chamber assembly comprising:a chamber; a piston slideably received in said chamber, said piston having a first piston side and a second piston side; a first inlet for communicating a fluid into said chamber on said first piston side: a second inlet for communicating a fluid into said chamber on said second piston side; an actuator movable between a first position and a second position, said actuator for selectively opening said first inlet and closing said second inlet when in said first position and said actuator for selectively closing said first inlet and opening said second inlet when in said second position wherein said piston is coupled to drive said actuator between said first position and said second position; and said actuator comprising a member rotatable by said piston between said first position and said second position.
- 4. The piston chamber assembly of claim 3 wherein said piston is slideable relative to said member.
- 5. The piston chamber assembly of claim 4 wherein said member has a cam selectively in contact with said piston to rotate said member between said first position and said second position.
- 6. The piston chamber assembly of claim 5 wherein said piston is slideably mounted to a groove in said member, said cam defining a portion of said groove.
- 7. The piston chamber assembly of claim 3 wherein said member has a fist portion with a first opening for communicating fluid from said first inlet into said chamber on said first piston side when said actuator is in said first position and a second portion with a second opening for communicating fluid from said second inlet into said chamber on said second piston side when said actuator is in said second position.
- 8. The piston chamber assembly of claim 7 wherein said first portion close said first inlet in said second position and said second portion closing said second inlet in said first position.
- 9. A piston chamber assembly comprising:a chamber; a piston slideably received in said chamber, said piston having a first piston side and a second piston side; a first inlet for communicating a fluid into said chamber on said first piston side; a second inlet for communicating a fluid into said chamber on said second piston side; an actuator movable between a first position and a second position, said actuator for selectively opening said first inlet and closing said second inlet when in said first position and said actuator for selectively closing said first inlet and opening said second inlet when in said second position wherein said piston is coupled to drive said actuator between said first position and said second position; wherein said actuator comprises a member in said chamber, said member selectively rotatable between a first direction towards said first position and a second direction towards said second position; and wherein said piston is arranged to impart momentum to said actuator selectively between said first direction and said second direction, thereby moving said actuator between said first position and said second position.
- 10. The piston chamber assembly of claim 9 wherein said piston is slideable relative to said member.
- 11. The piston chamber assembly of claim 10 wherein said member has a cam selectively in contact with said piston to rotate said member between said first position and said second position.
- 12. The piston chamber assembly of claim 11 wherein said piston is slideably mounted to a groove in said member, said cam defining a portion of said groove.
- 13. The piston chamber assembly of claim 9 wherein said member has a first portion with a first opening for communicating fluid from said first inlet into said chamber on said first piston side when said actuator is in said first position and a second portion with a second opening for communicating fluid from said second inlet into said chamber on said second piston side when said actuator is in said second position.
US Referenced Citations (2)
Number |
Name |
Date |
Kind |
2786452 |
Tucker |
Mar 1957 |
A |
3027876 |
Strick |
Apr 1962 |
A |