U.S. patent application number 10/747048 was filed with the patent office on 2005-07-07 for cylinder apparatus with a capability of detecting piston position in a cylinder.
This patent application is currently assigned to KSP TECHNOLOGIES CORP.. Invention is credited to Chuang, Yun-Ching.
Application Number | 20050146252 10/747048 |
Document ID | / |
Family ID | 34710763 |
Filed Date | 2005-07-07 |
United States Patent
Application |
20050146252 |
Kind Code |
A1 |
Chuang, Yun-Ching |
July 7, 2005 |
Cylinder apparatus with a capability of detecting piston position
in a cylinder
Abstract
A cylinder apparatus with a capability of detecting a piston
position includes a cylinder, a throttling valve, a positive limit
and a pressure switch. A piston is movably mounted in the cylinder.
A piston rod with an outside end protruding out of the cylinder is
attached to the piston and adapted to push an object. The cylinder
is connected to a pump with pipes. The throttling valve and the
pressure switch are connected to the pipes, and the pressure switch
is installed between the cylinder and the throttling valve.
Consequently, when the pump starts pumping, the piston rod pushes
the object to abut the positive limit. The stopped movement of the
piston rod will change the pressure in the cylinder that triggers
the pressure switch to send a signal to a controlling host to stop
the pump.
Inventors: |
Chuang, Yun-Ching;
(Taichung, TW) |
Correspondence
Address: |
Dennison, Schultz & Dougherty & MacDonald
Suite 105
1727 King Street
Alexandria
VA
22314
US
|
Assignee: |
KSP TECHNOLOGIES CORP.
|
Family ID: |
34710763 |
Appl. No.: |
10/747048 |
Filed: |
December 30, 2003 |
Current U.S.
Class: |
312/223.2 |
Current CPC
Class: |
F15B 2211/46 20130101;
F15B 2211/75 20130101; F15B 2211/30525 20130101; F15B 2211/7053
20130101; F15B 2211/6313 20130101; F15B 2211/41527 20130101; F15B
2211/473 20130101; F15B 2211/40515 20130101; F15B 2211/455
20130101; F15B 11/042 20130101; F15B 2211/40584 20130101; F15B
15/2838 20130101; F15B 11/044 20130101; F15B 2211/20538
20130101 |
Class at
Publication: |
312/223.2 |
International
Class: |
A47B 081/00; A47B
097/00 |
Claims
What is claimed is:
1. A cylinder apparatus with a capability of detecting piston
position in a cylinder of a cylinder and the cylinder apparatus
comprising: a cylinder having a closed tubular housing with a
chamber defined in the closed tubular housing and adapted to
connect to a pump with pipes; a piston movably mounted in the
chamber in the closed tubular housing and splitting the chamber
into a retracting chamber and a protruding chamber; and an
actuating device coupled to the piston and adapted to selectively
push and carry an object; a positive limit positioned corresponding
to the actuating device adapted to stop movement of the actuating
device; a first throttling valve selectively connected to the pipes
between one of the retracting and the protruding chambers and the
pump; and a first pressure switch connected to the pipes between
the first throttling valve and the chamber.
2. The cylinder apparatus as claimed in claim 1, wherein the
actuating device is a piston rod with an inside end and an outside
end, the inside end of the piston rod attached to the piston in the
closed tubular housing and the outside end of the piston rod
extending out of the closed tubular housing and adapted to push the
object to abut the positive limit.
3. The cylinder apparatus as claimed in claim 2, wherein the first
throttling valve is connected to the pipes between the retracting
chamber in the closed tubular housing and the pump, and the first
pressure switch is connected to the pipes between the retracting
chamber in the closed tubular housing and the first throttling
valve.
4. The cylinder apparatus as claimed in claim 2, wherein the first
throttling valve is connected to the pipes between the protruding
chamber in the closed tubular housing and the pump, and the first
pressure switch is connected to the pipes between the protruding
chamber in the closed tubular housing and the first throttling
valve.
5. The cylinder apparatus as claimed in claim 4, wherein the
cylinder apparatus further comprises a second throttling valve
connected to the pipes between the retracting chamber in the closed
tubular housing and the pump, and a second pressure switch
connected to the pipes between the retracting chamber in the closed
tubular housing and the second throttling valve.
6. The cylinder apparatus as claimed in claim 3, wherein the first
throttling valve is one-directional.
7. The cylinder apparatus as claimed in claim 4, wherein the first
throttling valve is one-directional.
8. The cylinder apparatus as claimed in claim 5, wherein both the
first and the second throttling valves are one-directional.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a cylinder apparatus, and
more particularly to a hydraulic or pneumatic system cylinder
apparatus with a capability of detecting a piston position in a
cylinder of the cylinder apparatus.
[0003] 2. Description of Related Art
[0004] In most hydraulic and pneumatic powered devices, cylinder
apparatuses are the basic actuating elements. With reference to
FIG. 4, a conventional cylinder apparatus with a capability of
detecting a piston position includes a cylinder (50), reed switches
(54) and permanent magnets (521). The cylinder (50) generally
includes a closed tubular housing (51), a piston (52) and a piston
rod (53). Since operation of the cylinder (50) is conventional, no
description of the cylinder (50) operation is provided.
[0005] The conventional method of detecting the piston (52)
position in a cylinder (50) uses the permanent magnets (521) and
reed switches (54). The permanent magnet (521) is ring shaped and
mounted around the piston (52). The reed switches (54) are
respectively strapped to specific positions on the closed tubular
housing (51). When the piston (52) moves toward top dead center or
bottom dead center in the closed tubular housing (51) and passes a
reed switch (54), the magnetic field of the permanent magnet (521)
will trigger the reed switch (54). The reed switch (54) will send
an electric signal to a host (not shown) that controls the entire
system and stops or starts the piston moving and determines the
direction of movement.
[0006] However, the conventional cylinder apparatus with a
capability of detecting the piston position in the cylinder (50)
still has the following shortcomings.
[0007] 1. Inconvenient Operation:
[0008] Because the reed switch (54) is strapped or clamped on the
closed tubular housing (51), the reed switches (54) must be
repeatedly unclamped and clamped to change or adjust the piston
(52) position in the cylinder (50) to push an object to a required
position. Especially, when the cylinder (50) is mounted inside a
complex machine, unclamping or clamping the reed switches (54) is
not easy and is inconvenient.
[0009] 2. Limited Application:
[0010] As described in the foregoing description, the reed switches
(54) sense the magnetic field induced by the permanent magnets
(521) and send out an electric signal to the host. However, if the
conventional cylinder apparatus is used in a machine that has a
strong magnetic field around or in the machine, the reed switches
(54) will sense the strong magnetic field and lose its capability
to sense the position of the piston (52) correctly. Therefore,
applications of the cylinder apparatus are significantly diminished
and can only be used in machines that do not have strong magnetic
fields. To overcome the shortcomings, the present invention
provides a cylinder apparatus with a capability of detecting a
piston position in a cylinder of the cylinder apparatus to mitigate
or obviate the aforementioned problems.
SUMMARY OF THE INVENTION
[0011] The main objective of the invention is to provide a cylinder
apparatus with a capability of detecting a piston position that is
convenient to use.
[0012] Another objective of the invention is to provide a cylinder
apparatus that can be broadly used in any hydraulic and pneumatic
device.
[0013] Other objectives, advantages and novel features of the
invention will become more apparent from the following detailed
description when taken in conjunction with the accompanying
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1 is a block diagram of a cylinder apparatus in
accordance with the present invention used in a simple hydraulic
system;
[0015] FIG. 2 is a schematic diagram of the cylinder apparatus in
FIG. 1 used in a simple hydraulic system;
[0016] FIG. 3 is a schematic diagram of an alternative embodiment
of the cylinder apparatus used in a simple hydraulic system;
and
[0017] FIG. 4 is a side plan view of a conventional cylinder
apparatus with a capability of detecting piston position in a
cylinder.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENT
[0018] With reference to FIGS. 1 and 2, a cylinder apparatus with a
capability of detecting piston position comprises a cylinder (10),
pressure switches (20), throttling valves (30, 30') and a positive
limit (40). The cylinder apparatus can be used in a hydraulic
system or a pneumatic system. A double-acting cylinder with a
piston rod used in a hydraulic system is described, but a person
skilled in the art will recognize that a single-acting cylinder or
a double-acting cylinder with two opposite piston rods can be
used.
[0019] The cylinder (10) is connected to a pumping device (not
numbered) of the hydraulic system. The pumping device has a pump
(60), pipes (not numbered) and directional control valves (61). The
pump (60) is electrically connected to a controlling host (not
shown) and pumps hydraulic fluid into the cylinder (10) via the
pipes.
[0020] The cylinder (10) includes a closed tubular housing (11), a
piston (12) and an actuating device (not numbered). A complex
hydraulic system can be constructed with the pump (60), the
directional control valves (61) and the pipes, and a sophisticated
cylinder (10) can also be constructed with the closed tubular
housing (11), the piston (12) and the actuating device. A chamber
(not number) is defined in the closed tubular housing (11), and the
piston (12) is movably mounted in the chamber to move reciprocally
in the closed tubular housing (11) and splits the chamber into a
protruding chamber (111) and a retracting chamber (112). The
actuating device is attached to the piston (12) and is adapted to
push or carry an object to a proper position, where a next process
will deal with the object. The actuating device in this preferred
embodiment is a piston rod (13) with an inside end (not numbered)
and an outside end (not numbered). The actuating device could be a
carrier (not shown) attached to the piston (12) to carry the object
for rodless cylinders, such as magnetic rodless cylinders. The
inside end of the piston rod (13) is attached to the piston (12) in
the closed tubular housing (11). The outside end of the piston rod
(13) protrudes out of the closed tubular housing (11) and is
adapted to push the object, such as a bottle (41) to a proper
position.
[0021] The protruding and the retracting chambers (111, 112) are
respectively connected to the pump (60) by means of the pipes
through a directional control valve (61). The directional control
valve (61) is connected to the pipes between the pump (60) and the
cylinder (10) and is used to change the path of the hydraulic fluid
pumped out of the pump (60) into the two chambers (111, 112). A
throttling valve (30') is connected to the pipes between the
directional control valve (61) and the protruding chamber (111) in
the closed tubular housing (11) and is used to control the flow
rate of the hydraulic fluid flowing into or out of the protruding
chamber (111). Therefore, the piston rod (13) can smoothly move out
of the closed tubular housing (11) or smoothly retract into the
closed tubular housing (11) by changing the path and the flow rate
of the hydraulic fluid into the different chambers (111, 112). A
one-direction throttling valve (30) is connected to the pipes
between the directional control valve (61) and the retracting
chamber (112) in the closed tubular housing (11) and throttles the
flow rate of the hydraulic fluid flowing out of the retracting
chamber (112). The pressure switch (20) is connected to the pipes
between the one-direction throttling valve (30) and the retracting
chamber (112) and can be triggered by a pressure change in the
retracting chamber (112). The pressure switch (20) can convert a
physical signal to an electrical signal and send the electrical
signal to the controlling host that controls the pump (60) and the
directional control valve (61) to change the path of the hydraulic
fluid.
[0022] The positive limit (40) is positioned corresponding to the
outside end of the piston rod (13) with a given distance that
represents the proper position of the bottle (41) being moved. The
bottle (41) is pushed by the outside end of the piston rod (13) to
move until the bottle (41) abuts against the positive limit
(40).
[0023] To operate the cylinder apparatus, only an appropriate
pressure switch (20) has to be installed. When the hydraulic fluid
flows into the protruding chamber (111) by the pump (60)
continuously pumping, the pressure in the protruding chamber (111)
will be instantly increased. However, the pressure in both the
protruding chamber (111) and the retracting chamber (112) will be
equalized. Therefore, a force proportional to the pressure in the
protruding chamber (111) is produced and pushes the piston (12)
toward the retracting chamber (112) to equalize the pressure in
both chambers (111, 112). At the same time, the hydraulic fluid in
the retracting chamber (111) flows out and the flow rate of the
hydraulic fluid is controlled by the one-direction throttling valve
(30) such that the piston (12) can smoothly move. Thus, the bottle
(41) is pushed by the outside end of the piston rod (13) to move
until the bottle (41) abuts the positive limit (40). For an
instant, the pressure in the retracting chamber (112) will be
decreased while the movement of the bottle (41) is stopped by the
positive limit (40). The decrement of the pressure in the
retracting chamber (112) will trigger the pressure switch (20) to
send the electrical signal to the controlling host to stop pumping
or changing the path of the hydraulic fluid. At this time, the
piston rod (13) can be retracted, and the bottle (41) is pushed to
the proper position, where a next process in a product line is
prepared to handle the bottle (41), such as a sealing process for
the bottle (41).
[0024] The pressure in the retracting chamber (112) is generally
changed as the outside end of the piston rod (13) pushes the bottle
(41) to abut the positive limit (40) each time. Therefore, the
given distance between the positive limit (40) and an original
position of the outside end of the piston rod (13) will represent a
proper movement of the bottle (41). Consequently, the movement of
the piston rod (13) will be equal to the given distance between the
positive limit (40) and the original position of the outside end of
the piston rod (13). Manufactures only have to adjust the positive
limit (40) corresponding to the outside end of the piston rod (13).
The object, such as the bottle (41) will always be pushed to abut
the positive limit (40) with the proper position, where the sealing
process deals with the bottle (41).
[0025] With reference to FIG. 3, an alternative embodiment of the
invention has an additional feature that can be implemented with a
one-direction throttling valve (30) and a pressure switch (20)
connected to the pipes between the protruding chamber (111) and the
directional control valve (61). In such a structure, when the
outside end of the piston rod (13) pushes the bottle (41) against
the positive limit (40), the pressure in the retracting chamber
(112) will decrease and the pressure in the protruding chamber
(111) will increase. Therefore, the controlling host can receive
two electrical signals that are respectively sent out by the two
pressure switches (20) that are respectively triggered by the
changes of the pressure in the chambers (111, 112). The controlling
host can compare with the two signals and take a suitable action to
position the bottle (40) in an exact position each time. For
instance, if the controlling host does not receive the signals sent
out by both the pressure switches (20) at the same time, one of the
pressure switches (20) may be broken down or working abnormally.
The controlling host could stop the movement of the piston (12) and
send out alarms to notify a repairman to check the pressure
switches (20) to avoid any possible mistakes occurring.
[0026] The cylinder apparatus is very convenient to adjust. The
pressure switch (20) can be installed and connected to the pipes at
any conveniently and easily accessible position to make replacement
of the pressure switch (20) convenient and easy. The pressure
switches (20) are standard products in the hydraulic and pneumatic
actuating industry, and a proper pressure switch (20) is
conveniently selected to install. Also, the cylinder apparatus with
a capability of detecting a piston position as described overcomes
interference by spurious magnetic fields.
[0027] Even though numerous characteristics and advantages of the
present invention have been set forth in the foregoing description,
together with details of the structure and function of the
invention, the disclosure is illustrative only, 11 and changes may
be made in detail, especially in matters of shape, size, and
arrangement of parts within the principles of the invention to the
full extent indicated by the broad general meaning of the terms in
which the appended claims are expressed.
* * * * *