Information
-
Patent Grant
-
6779985
-
Patent Number
6,779,985
-
Date Filed
Tuesday, October 15, 200222 years ago
-
Date Issued
Tuesday, August 24, 200420 years ago
-
Inventors
-
Original Assignees
-
Examiners
Agents
-
CPC
-
US Classifications
Field of Search
US
- 417 65
- 417 179
- 417 180
- 417 182
- 417 187
- 417 186
-
International Classifications
-
Abstract
A vacuum generating device designed to generate negative pressure in an absorption means, such as an absorption pad, of a vacuum system, is disclosed. The vacuum generating device accomplishes the recent trend of compactness and smallness of such devices, effectively protects its ejector unit from damage, and does not have an increased production cost in comparison with conventional vacuum generating devices. The vacuum generating device includes a block body having an air inlet port, a vacuum port, and an air outlet port, an ejector unit functioning to generate negative pressure in response to an action of compressed air flowing thereto via the air inlet port, and a control valve mechanism functioning to open or close air supply paths branching from a main flow path to an air inlet chamber of the ejector unit and the vacuum port. The block body has a recess, formed by depressing a surface of the block body to a predetermined depth. The ejector unit is formed in the recess by depressing predetermined portions of the recess. A cover is set in the recess of the block body to seal the ejector unit from the outside.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates, in general, to vacuum generating devices and, more particularly, to a vacuum generating device designed to generate negative pressure in an absorption means, such as an absorption pad, of a vacuum system, such as a vacuum feeding system used on a production line, and release the negative pressure from the absorption means.
2. Description of the Prior Art
As well known to those skilled in the art, ejectors have been typically used for generating negative pressure in an absorption means in a vacuum system. Such an ejector may be separately installed in a vacuum system, to be used independently. Alternatively, such an ejector may be designed such that it constitutes a vacuum generating device in cooperation with some elements, such as a block body, a valve mechanism, etc., of the vacuum system.
Japanese Patent Laid-open Publication No. Heisei. 11-114862 discloses a typical example of conventional vacuum generating devices for such vacuum systems. The above conventional vacuum generating device comprises a single block body having a compressed air path, an ejector used for generating negative pressure in response to an action of the compressed air, and a control valve mechanism used for opening or closing the compressed air path of the block body. The ejector is provided at a side surface of the block body, while the control valve mechanism is provided in an upper portion of the block body. The vacuum generating device generates negative pressure in an absorption means of a vacuum system, and quickly releases negative pressure from the absorption means, as desired. Therefore, the vacuum generating device may be preferably used in a variety of vacuum systems, such as a vacuum feeding system used in an automated production line to feed workpieces to target places. However, the vacuum generating device is problematic in that the ejector is exposed outside the side surface of the block body, thus undesirably increasing the size of the device and being undesirably and easily removed from the block body by external shock.
In an effort to improve the structure and operational function of conventional vacuum generating devices, such as the above-mentioned Japanese device, U.S. Pat. No. 6,416,295 discloses another vacuum generating device, comprising a main body including four functional blocks arranged longitudinally and continuously, an ejector installed in the main body, and a control valve mechanism provided in an upper portion of the main body. The object of the above U.S. patent is to accomplish the recent trend of compactness and smallness of such vacuum generating devices by reducing the width of the device. However, the vacuum generating device disclosed in the above U.S. patent is problematic in that an undesired increase in the length of the device has resulted even though the device has a reduced width, so that compactness or smallness of the device has not been achieved. Another problem experienced in the vacuum generating device of the above U.S. patent resides in that the number of parts of the device has increased, resulting in an undesired increase in the production cost of the device.
SUMMARY OF THE INVENTION
Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and an object of the present invention is to provide a vacuum generating device, which accomplishes the recent trend of compactness and smallness of such devices, which effectively protects its ejector unit from damage, and does not have an increased production cost in comparison with conventional vacuum generating devices.
In order to accomplish the above objects, the present invention provides a vacuum generating device, comprising a block body having an air inlet port, a vacuum port and an air outlet port, an ejector unit functioning to generate negative pressure in response to an action of compressed air flowing into the ejector unit via the air inlet port, and a control valve mechanism functioning to open or close air supply paths branching from a main flow path to an air inlet chamber of the ejector unit and the vacuum port, the main flow path communicating with the air inlet port.
The present invention is characterized in that the block body has a recess, formed by depressing the surface of the block body to a predetermined depth, the ejector unit is formed in the recess by depressing predetermined portions of the recess, and a cover is set in the recess of the block body to seal the ejector unit from the outside. Preferably, the cover is designed such that its thickness is not greater than the depth of the recess of the block body.
In the present invention, the ejector unit is integrally formed in the block body such that the ejector unit is not exposed to the outside of the block body. Therefore, the vacuum generating device accomplishes the recent trend of compactness and smallness of such devices, and effectively protects its ejector unit from damage.
BRIEF DESCRIPTION OF THE DRAWINGS
The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:
FIG. 1
is a perspective view of a vacuum generating device in accordance with a preferred embodiment of the present invention;
FIG. 2
is an exploded perspective view of the vacuum generating device of
FIG. 1
;
FIG. 3
is a sectional view of the vacuum generating device of
FIG. 1
;
FIGS. 4
a
and
4
b
are views of a cover constituting the vacuum generating device according to the preferred embodiment of the present invention, in which:
FIG. 4
a
is a perspective view of the cover, and
FIG. 4
b
is a sectional view of the cover;
FIG. 5
is an exploded perspective view of an ON/OFF control valve constituting the vacuum generating device of
FIG. 2
;
FIG. 6
is a sectional view showing the operation of the vacuum generating device of
FIG. 3
, when a vacuum-on solenoid valve is in an ON-state; and
FIG. 7
is a sectional view showing the operation of the vacuum generating device of
FIG. 3
, when a vacuum-off solenoid valve is in an ON-state.
DETAILED DESCRIPTION OF THE INVENTION
Reference should now be made to the drawings, in which the same reference numerals are used throughout the different drawings to designate the same or similar components.
FIG. 1
is a perspective view of a vacuum generating device in accordance with a preferred embodiment of the present invention. As shown in the drawing, the vacuum generating device
10
of the present invention is produced in the form of a module, and comprises a block body
20
, with an air inlet port
21
, a vacuum port
22
and an air outlet port
23
formed on a side surface of the body
20
at upper, middle and lower portions, respectively. A rectangular recess
24
, having a predetermined depth, is formed on a surface of the body
20
, for example the front surface. A cover
50
is set in the recess
24
, and mounted to the block body
20
using setscrews. The vacuum generating device
10
also includes a control valve mechanism
70
. The valve mechanism
70
is installed in the upper portion of the block body
20
.
In the present invention, it is preferred to design the cover
50
such that its thickness does not exceed the depth of the recess
24
. Therefore, the cover
50
completely set in the recess
24
does not project from the surface of the block body
20
. Due to such a limited thickness of the cover
50
, it is possible to avoid a formation of undesired gap between devices
10
when closely arranging the devices
10
into a stack.
The valve mechanism
70
includes a support plate
81
and two solenoid valves
82
a
and
82
b
. The support plate
81
is mounted on the top surface of the block body
20
, while the two solenoid valves
82
a
and
82
b
are mounted on the top surface of the support plate
81
.
As shown in
FIG. 2
, an ejector unit
25
is provided in the recess
24
. The ejector unit
25
comprises a first air inlet chamber
26
, a first vacuum chamber
27
and a first air outlet chamber
28
which are formed in the recess
24
by depressing the walls of the recess
24
at predetermined portions, with a plurality of serial nozzle holes
29
and
30
formed in the ejector unit
25
to allow the chambers
26
,
27
and
28
to communicate with each other. The vacuum chamber
27
of the ejector unit
25
communicates with the vacuum port
22
, while the outlet chamber
28
communicates with the outlet port
23
. In such a case, it is preferable to allow the vacuum chamber
27
to communicate with the vacuum port
22
through an orifice
31
. A check valve
32
is installed in the orifice
31
such that the check valve
32
prevents reverse flow of air in a direction from the vacuum chamber
27
to the vacuum port
22
.
The ejector unit
25
creates an ejector pump
60
in cooperation with the cover
50
set in the recess
24
of the block body
20
. The cover
50
set in the recess
24
covers the three chambers
26
,
27
and
28
of the ejector unit
25
. When the cover
50
is set into the recess
24
, a gasket
39
having a specifically designed shape is closely interposed between the cover
50
and the inside wall of the recess
24
to prevent the chambers
26
,
27
and
28
from directly communicating with each other, thus preventing the direct flow of air between the chambers
26
,
27
and
28
.
In the present invention, the cover
50
may be produced in the form of a flat panel. However, in the preferred embodiment of the present invention, the cover
50
is produced in the form of an ejector plate including a second air inlet chamber, a second vacuum chamber and a second air outlet chamber, with a plurality of serial nozzle holes allowing the chambers of the ejector plate-type cover
50
to communicate with each other.
FIGS. 4
a
and
4
b
shows in detail the construction of the ejector plate-type cover
50
produced in the form of an ejector plate. In
FIGS. 4
a
and
4
b
, the reference numerals
51
,
52
,
53
and
54
denote a second air inlet chamber, a second vacuum chamber, a sub-vacuum chamber and a second air outlet chamber formed on the cover
50
, respectively. The reference numerals
55
,
56
and
57
respectively denote nozzle holes, allowing the chambers
51
,
52
,
53
and
54
to communicate with each other. The cover
50
preferably includes first and second nozzle spouts
58
a
and
58
b
which are set in two nozzle holes
55
and
56
, respectively, such that the nozzle spouts
58
a
and
58
b
are coupled to each other in the vacuum chamber
52
. A plurality of radial holes
59
are formed in the sidewall of the second nozzle spout
58
b
at positions around the coupled junction of the two spouts
58
a
and
58
b
. When the cover
50
is completely set in the recess
24
of the block body
20
, the inlet chamber
51
, vacuum chamber
52
and outlet chamber
54
of the cover
50
coincide and communicate with the inlet chamber
26
, vacuum chamber
27
, and the outlet chamber
28
of the ejector unit
25
, respectively.
Therefore, in the ejector pump
60
created by both the ejector unit
25
and the ejector plate-type cover
50
according to the preferred embodiment, several chambers
61
,
62
and
63
functioning as an air inlet chamber, a vacuum chamber, and an air outlet chamber have volumes larger than those of an ejector pump having a panel-type cover, as shown in FIG.
3
. Due to the enlarged volumes of the chambers
61
,
62
and
63
, the ejector pump
60
creates a high level of vacuum. In the ejector pump
60
, the chambers
26
,
27
and
28
of the ejector unit
25
communicate with each other through the nozzle holes
55
,
56
and
57
of the cover
50
, so that the ejector unit
25
may be not formed with the nozzle holes
29
and
30
which are separately holed in the unit
25
to allow the chambers
26
,
27
and
28
to communicate with each other. The two nozzle spouts
58
a
and
58
b
also preferably allow the pump
60
to more quickly create desired vacuum.
In the drawings, the reference numeral
33
denotes a dust collecting filter that is set in the vacuum port
22
, and the reference numeral
34
denotes a sound absorbing filter that is set in the outlet port
23
. A filter cap
35
is preferably mounted to the side surface of the block body
20
so as to hold the two filters
33
and
34
in their positions inside the two ports
22
and
23
without allowing an undesired removal of the filters
33
and
34
from the block body
20
. In such a case, the vacuum port
22
and the outlet port
22
and
23
are formed in the filter cap
35
, in place of the side surface of the block body
20
. The reference numeral
36
denotes a cover which covers a part of another outlet port
23
′.
Two valve bores
37
a
and
37
b
are vertically formed on the upper surface of the block body
20
at two spaced positions, such that the bores
37
a
and
37
b
perpendicularly meet a main flow path
40
which is formed in the block body
20
while axially extending from the inlet port
21
. The first bore
37
a
, positioned at the left side of the body
20
, communicates with the inlet chamber
26
of the ejector unit
25
via a first communication hole
42
a
which extends downward from the bottom of the first bore
37
a
to the inlet chamber
26
. In the same manner, the second bore
37
b
, positioned at the right side of the body
20
, communicates with the vacuum port
22
of the block body
20
via a second communication hole
42
b
which extends downward from the bottom of the second bore
37
b
, as shown in FIG.
3
. Therefore, compressed air introduced into the vacuum generating device
10
via the inlet port
21
may flow to the inlet chamber
26
of the ejector unit
25
and the vacuum port
22
through the first and second communication holes
42
a
and
42
b
, respectively. In the vacuum generating device
10
, the two communication holes
42
a
and
42
b
thus respectively constitute compressed air supply paths for the inlet chamber
26
of the ejector unit
25
and the vacuum port
22
. However, the flow of inlet compressed air inside the vacuum generating device
10
is controlled by an operation of the valve mechanism
70
such that the inlet compressed air selectively flows to only one of the inlet chamber
26
and the vacuum port
22
. That is, the valve mechanism
70
controllably opens or closes the first and second communication holes
42
and
42
b
which respectively branch from the main flow path
40
to the inlet chamber
26
of the ejector unit
25
and the vacuum port
22
. In the drawings, the reference numeral
38
denotes a control screw that is threaded into the block body
20
to allow a user to adjust the opening ratio of the second communication hole
42
b
to control the speed of releasing vacuum from the vacuum chamber
62
, as desired.
The construction and operation of the control valve mechanism
70
will be described herein below. However, it should be understood that the construction of the valve mechanism
70
may be altered without being limited to the following construction, if the alteration does not affect the functioning of the present invention.
The control valve mechanism
70
comprises two ON/OFF control valves
71
a
and
71
b
that are set in the two valve bores
37
a
and
37
b
, respectively. The control valve mechanism
70
also includes the support plate
81
and two solenoid valves
82
a
and
82
b
. The support plate
81
is mounted to the top surface of the block body
20
, such that the plate
81
receives the upper portions of the two ON/OFF control valves
71
a
and
71
b
. Of the two solenoid valves
82
a
and
82
b
mounted on the top surface of the support plate
81
, the former
82
a
functions as a vacuum-on solenoid valve, while the latter
82
b
functions as a vacuum-off solenoid valve.
In the present invention, the two ON/OFF control valves
71
a
and
71
b
are pneumatic control valves that are pneumatically operated to change their state from a normal OFF-state to an ON-state. The two solenoid valves
82
a
and
82
b
are normally closed-type solenoid valves.
As shown in
FIG. 5
, each of the two ON/OFF control valves
71
a
and
71
b
comprises a cylindrical retainer
72
and a valve body
77
which may be assembled with each other into a single body. The retainer
72
is an integrated cylindrical body, which is hollowed along its central axis, with upper and lower end parts
73
and
74
having the same outer diameter, and an intermediate part
75
having an outer diameter smaller than that of the two end parts
73
and
74
. An opening
76
is formed at a sidewall of the intermediate part
75
. The valve body
77
is an integrated member, including a valve head
78
and a valve stem
79
. The diameter of the valve head
78
is determined such that the head
78
is seated on the top end of the retainer
72
. The valve stem
79
integrally extends downward from the center of the valve head
78
such that the valve stem
79
movably and axially passes the central bore of the retainer
72
. A rubber ring
80
is fitted over the lower end of the valve stem
79
, and has a diameter capable of allowing the ring
80
to seal the lower end of the central bore of the retainer
72
in a normal state.
As shown in
FIG. 3
, the retainer
72
of each valve
71
a
,
71
b
is installed in an associated valve bore
37
a
,
37
b
such that the upper and lower end parts
73
and
74
are in close contact with the inner surface of the bore
37
a
,
37
b
while the valve body
77
is installed in the valve bore
37
a
,
37
b
such that it is linearly movable within a predetermined range in a vertical direction. In such a case, the intermediate part
75
of each retainer
72
is positioned at the same level as the main flow path
40
extending horizontally from the inlet port
21
. Therefore, the intermediate parts
75
of the retainers
72
do not block the main flow path
40
. In a normal state of the two ON/OFF control valves
71
a
and
71
b
, the lower ends of the retainers
72
are closed by the rubber rings
80
of the valve bodies
77
, so that the first and second communication holes
42
a
and
42
b
, in a normal state of the valves
71
a
and
71
b
, are closed.
As described above, the two ON/OFF control valves
71
a
and
71
b
are pneumatic control valves that are pneumatically operated to change their state from a normal OFF-state to an ON-state. In order to pneumatically actuate the two ON/OFF control valves
71
a
and
71
b
, the main flow path
40
has two branch paths
41
a
and
41
b
that supply compressed air to the top surfaces of the valve heads
78
of the two ON/OFF control valves
71
a
and
71
b
, respectively. The two normally closed-type solenoid valves
82
a
and
82
b
are installed at positions where the solenoid valves
82
a
and
82
b
control the first and second branch paths
41
a
and
41
b
, respectively. In a detailed description, the first branch path
41
a
primarily extends upwardly from the main flow path
40
in a vertical direction at a left side of the block body
20
, upwardly passes the support plate
81
, passes the vacuum-on solenoid valve
82
a
in an ON-state, and finally passes downwardly the support plate
81
until the path
41
a
communicates with the top surface of the valve head
78
of the first ON/OFF control valve
71
a
. In the same manner, the second branch path
41
b
primarily extends upwardly from the main flow path
40
in a vertical direction at a right side of the block body
20
, upwardly passes the support plate
81
, passes the vacuum-off solenoid valve
82
b
in an ON-state, and finally passes downwardly the support plate
81
until the path
41
b
communicates with the top surface of the valve head
78
of the second ON/OFF control valve
71
b
. Since the two solenoid valves
82
a
and
82
b
are normally closed-type solenoid valves as described above, the two branch paths
41
a
and
41
b
are maintained at their closed states during a normal state of the two solenoid valves
82
a
and
82
b.
In order to use the vacuum generating device
10
of the present invention, an absorption means (not shown) of a vacuum system is connected to the vacuum port
22
of the device
10
, while an external compressed air source (not shown) is connected to the inlet port
21
of the device
10
. When the vacuum-on solenoid valve
82
a
is switched into its ON-state, compressed air is fed to the main flow path
40
through the inlet port
21
, and passes through the first branch path
41
a
to impose pneumatic pressure to the top surface of the valve head
78
of the first ON/OFF control valve
71
a
. The valve body
77
of the first ON/OFF control valve
71
a
moves downward by a predetermined distance, so that a clearance C
1
is created between the rubber ring
80
and the lower end of the central bore of the retainer
72
of the valve
71
a
, as shown in FIG.
6
. Therefore, inlet compressed air in the main flow path
40
sequentially passes through the opening
76
formed at the sidewall of the intermediate part
75
of the retainer
72
, the clearance C
1
, and the first communication hole
42
a
, thus being fed to the inlet chamber
61
of the ejector pump
60
. The compressed air in the inlet chamber
61
sequentially flows through the nozzle holes
55
,
56
and
57
to pass the vacuum chamber
62
and the outlet chamber
63
, thus being discharged from the device
10
to the outside via the outlet port
23
. During such an operation of the vacuum generating device
10
, air in the absorption means, such as an absorption pad connected to the vacuum port
22
, is sucked into the vacuum chamber
62
through the orifice
31
, and is discharged from the device
10
to the outside along with the compressed air. Desired vacuum is thus created in the vacuum chamber
62
, so that desired negative pressure is generated in the absorption means and allows the absorption means to take a target material, such as a workpiece.
On the other hand, when the vacuum-off solenoid valve
82
b
is switched into its ON-state, compressed air in the main flow path
40
passes through the second branch path
41
b
to impose pneumatic pressure to the top surface of the valve head
78
of the second ON/OFF control valve
71
b
. The valve body
77
of the second ON/OFF control valve
71
b
moves downward by a predetermined distance, so that a clearance C
2
is created between the rubber ring
80
and the lower end of the central bore of the retainer
72
of the valve
71
b
, as shown in FIG.
7
. Therefore, inlet compressed air in the main flow path
40
sequentially passes through the opening
76
formed at the sidewall of the intermediate part
75
of the retainer
72
, the clearance C
2
, and the second communication hole
42
b
, thus being fed to the vacuum port
22
. Therefore, vacuum is quickly eliminated from the vacuum chamber
62
, so that negative pressure is released from the absorption means. In the vacuum generating device
10
of the present invention, it is possible to adjust the vacuum releasing speed by appropriately tightening or loosening the control screw
38
relative to the body
20
such that the opening ratio of the second communication hole
42
b
is adjusted by the inside end of the control screw
38
.
As described above, the present invention provides a vacuum generating device preferably used in a variety of vacuum systems, such as a vacuum feeding system. In the vacuum generating device of the present invention, an ejector unit is integrally formed in a block body by recessing a surface of the block body at a predetermined portion. A cover covers the ejector unit, thus preventing exposure of the ejector unit to the outside of the block body. Therefore, the vacuum generating device of this invention accomplishes the recent trend of compactness and smallness of such devices, effectively protects its ejector unit from damage, and does not increase its production cost in comparison with conventional vacuum generating devices.
Although a preferred embodiment of the present invention has been described for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.
Claims
- 1. A vacuum generating device, comprising a block body having an air inlet port, a vacuum port and an air outlet port; an ejector unit functioning to generate negative pressure in response to an action of compressed air flowing into the ejector unit via the air inlet port; and a control valve mechanism functioning to open or close air supply paths branching from a main flow path to an air inlet chamber of the ejector unit and the vacuum port, said main flow path communicating with the air inlet port, whereinsaid block body has a recess, said recess being formed by depressing a surface of the block body to a predetermined depth; said ejector unit comprises a first air inlet chamber, a first vacuum chamber and a first air outlet chamber which are formed in said recess by depressing predetermined portions of the recess and respectively communicate with the air inlet port, the vacuum port and the air outlet port of said block body, with communicating means for allowing the first air inlet chamber, first vacuum chamber, and the first air outlet chamber to communicate with each other; and a cover is set in said recess of the block body to seal the first air inlet chamber, first vacuum chamber, and the first air outlet chamber of the ejector unit from the outside.
- 2. The vacuum generating device according to claim 1, wherein said communicating means comprises a plurality of serial nozzle holes formed in the ejector unit such that the nozzle holes allow the first air inlet chamber, first vacuum chamber, and the first air outlet chamber to communicate with each other.
- 3. The vacuum generating device according to claim 1, wherein said cover comprises an ejector plate-type cover, with a second air inlet chamber, a second vacuum chamber and a second air outlet chamber formed on the cover so as to correspond to and coincide with the first air inlet chamber, the first vacuum chamber, and the first air outlet chamber of the ejector unit, respectively, said cover also having a plurality of serial nozzle holes allowing the second air inlet chamber, second vacuum chamber, and the second air outlet chamber to communicate with each other.
- 4. The vacuum generating device according to claim 1, wherein said cover has a thickness not greater than the depth of said recess of the block body.
- 5. The vacuum generating device according to claim 3, wherein said cover is provided with two nozzle spouts, said nozzle spouts being set in the nozzle holes of the cover, respectively, such that the nozzle spouts are coupled to each other in the second vacuum chamber of the cover, with a hole formed in a sidewall of the nozzle spouts at a position around a coupled junction of said two nozzle spouts.
- 6. The vacuum generating device according to claim 2, wherein said cover has a thickness not greater than the depth of said recess of the block body.
- 7. The vacuum generating device according to claim 3, wherein said cover has a thickness not greater than the depth of said recess of the block body.
Priority Claims (1)
Number |
Date |
Country |
Kind |
2001-63300 |
Oct 2001 |
KR |
|
US Referenced Citations (10)
Foreign Referenced Citations (1)
Number |
Date |
Country |
11-114862 |
Oct 1997 |
JP |