Information
-
Patent Grant
-
6585173
-
Patent Number
6,585,173
-
Date Filed
Thursday, July 11, 200222 years ago
-
Date Issued
Tuesday, July 1, 200321 years ago
-
Inventors
-
Original Assignees
-
Examiners
-
CPC
-
US Classifications
Field of Search
US
- 239 71
- 239 74
- 239 290
- 239 296
- 239 398
- 239 413
- 239 414
- 239 415
- 239 4175
- 239 526
- 239 528
- 239 527
- 239 DIG 14
- 073 714
- 073 753
- 073 756
-
International Classifications
-
Abstract
The invention relates to a paint spray gun with a paint nozzle placed on a gun body, an air nozzle placed around the paint nozzle, a compressed air valve placed within a piston borehole in the gun body, a compressed air borehole running through a handgrip of the gun body to the piston borehole, and a pressure-sensing and pressure display device placed in the hand grip. For sensing and displaying the spray pressure, a tube is placed in the compressed air borehole at a distance from its inner wall. The tube forms, in the interior, a channel for the compressed air supply to a part of the piston borehole placed upstream of the compressed-air valve, and borders an intermediate space between its exterior and the inner wall of the compressed air borehole. The intermediate space is connected via a first connecting channel with a pressure chamber placed downstream of the compressed-air valve and via a second connecting channel with a pressure gauge chamber in the handgrip allocated to the pressure-sensing and pressure display device.
Description
FIELD OF THE INVENTION
The invention relates to a paint spray gun.
BACKGROUND OF THE INVENTION
To achieve optimal results with paint spray guns, it is extremely important to set the spray pressure so as to obtain optimal atomization at a good operating speed and high application efficiency. For a precise setting of the pressure or monitoring of the input pressure, a pressure regulating valve with a pressure gauge is often added at the air inlet. However, the operation of the spray gun is impeded by the pressure regulating valve and pressure gauge, which are usually attached to the underside of the gun handgrip.
The Sata company therefore developed a spray gun, for example, marketed under the name of “Sata jet RP, Digital,” in which the pressure-sensing and pressure display device is built into the grip of the gun body. In this known spray gun, a connecting borehole is provided at the bottom end of the handgrip, from the compressed air supply borehole running through the pistol grip to a pressure gauge chamber placed in the handgrip. Through such an arrangement, however, only the gun air inlet pressure can be monitored, not the spray pressure adjustable through a valve system.
SUMMARY OF THE INVENTION
An object of the invention, therefore, is to create a spray gun that facilitates the sensing and display of the spray pressure using simple means.
The invention relates to a paint spray gun with a paint nozzle placed on a gun body, an air nozzle placed around the paint nozzle, a compressed air valve placed within a piston borehole in the gun body, a compressed air borehole running through a handgrip of the gun body to the piston borehole, and a pressure-sensing and pressure display device placed in the hand grip. For sensing and displaying the spray pressure, a tube is placed in the compressed air borehole at a distance from its inner wall. The tube forms, in the interior, a channel for the compressed air supply to a part of the piston borehole placed upstream of the compressed-air valve, and borders an intermediate space between its exterior and the inner wall of the compressed air borehole. The intermediate space is connected via a first connecting channel with a pressure chamber placed downstream of the compressed-air valve and via a second connecting channel with a pressure gauge chamber in the handgrip allocated to the pressure-sensing and pressure display device.
In the spray gun according to the invention, the compressed air can be conducted through the tube inserted into the compressed air borehole to the valve system that can be actuated by a trigger, while the intermediate space formed between the inner wall of the compressed air borehole and the outer wall of the tube can be used for a compressed air connection between a pressure chamber placed downstream of the valve system and a pressure-sensing and pressure display device integrated into the handgrip of the gun body. Through the intermediate space and easily manufacturable connecting boreholes, the spray pressure that can be adjusted through the valve system can also be displayed without connection channels that are expensive to manufacture.
The use of a digital display device that is normally activated only when a predetermined pressure threshold is exceeded has the advantage, through the design according to the invention, of longer battery life for supplying power to the display device, since pressure is displayed only when the trigger is actuated.
Other embodiments may include additional features. Thus, for example, the connection between the pressure chamber downstream of the valve system and the intermediate space can be produced in a technically simple manner through a first connecting borehole, shifted to the side of the mid-axis of the compressed air borehole, and which runs diagonally through outside the handgrip to the pressure chamber, and is connected in a middle region with the intermediate space. At its outer end, the first connection borehole is sealed through a ball or another suitable sealing element.
The connection from the intermediate space to the pressure gauge chamber placed in the gun grip may also be accomplished through a second connecting borehole that runs expediently from the inlet of the compressed air borehole diagonally through the handgrip to the pressure gauge chamber. In this way, the second connecting borehole need not be sealed by a ball or the like, as is necessary with the first connecting borehole. The first and/or the second connecting borehole are, in a further advantageous embodiment, designed at least partially as capillary boreholes. Through such a capillary, solvents used for cleaning the spray gun, or even lacquer or paint residue can be prevented from reaching the area of the pressure sensor and consequently impairing or hindering the proper gauging of the pressure.
BRIEF DESCRIPTION OF THE DRAWINGS
Further particularities and advantages of the invention are revealed in the following description of a preferred embodiment using the drawing. Shown are:
FIG. 1
is a partial cross section of a view of a paint spray gun according to the invention; and
FIG. 2
is a gun body of a paint spray gun according to the invention.
DETAILED DESCRIPTION OF THE INVENTION
The paint spray gun shown in
FIG. 1
has a gun body
1
with a handgrip
2
and an upper part
3
, on which a suspension hook
4
is shaped. Running through the upper part
3
is a multi-graduated through hole
5
that goes all the way from front to back, in which a nozzle needle
6
is led in an axially adjustable manner. The through hole
5
exhibits a front region
7
with an expanded diameter, into which a diagonal inlet borehole
8
with an internal screw thread
9
for screwing on a paint reservoir, not shown, leads.
Provided on the front end of the through hole
5
is an internal screw thread
10
, through which a paint nozzle
11
is screwed into the upper part
3
of the gun body
1
. The paint nozzle
11
includes on its front end a nozzle borehole
12
, which together with a tapering front end-part of the nozzle needle
6
, axially movable through a trigger
13
, constitutes an adjustable inlet for the paint, the lacquer, or the like. To adjust the nozzle needle, the trigger
13
, coupled to the gun body
1
through a pin
14
, includes a crosspin
16
through which the nozzle needle
6
runs, and which is arranged within a recess
15
in the gun body
1
. On the nozzle needle
6
, a needle sleeve
17
is fixed, whose front end the crosspin
16
of the trigger
13
reaches upon pulling back towards the apparatus. Lying against the rear end of the needle sleeve
17
is the front end of a compression spring
18
, which supports itself with its rear end on a paint quantity adjusting screw
20
secured by a lock nut
19
. By pulling back the trigger
13
, the nozzle needle
6
is moved to the back against the force of the compression spring so that the nozzle borehole
12
opens to release the paint.
An air nozzle
21
with an air cap
23
that can be fastened through a swivel nut
22
on the upper part
3
of the gun body
1
and an air distribution ring
24
are placed around the paint nozzle
11
. A ring slot
25
surrounding the nozzle borehole
12
of the paint nozzle
11
is bordered by the air cap
23
. Moreover, so-called horn air boreholes
27
for jet formation are placed in forward-protruding horns
26
of the air cap
23
. The compressed air supply to the air nozzle
21
takes place through compressed air boreholes at the side, not discernible in the sectional illustrations of
FIGS. 1 and 2
, which are connected with a pressure chamber
28
of a valve system
29
for controlling the compressed air supply to the air nozzle
21
.
The valve system
29
includes a valve piston
31
that can be actuated through the trigger
13
by means of a rod
30
, the valve piston together with a valve face
32
in a piston borehole
33
placed in the gun body
1
forming a compressed air valve between a part of the piston borehole
33
placed upstream of the valve face
32
, and the pressure chamber
28
connected to the air nozzle
21
downstream of the valve face
32
. In the part of the piston borehole
33
lying upstream of the valve face
32
, furthermore, a rotatable sleeve
34
is placed, exhibiting a cross hole
35
in the region of the opening of a compressed air borehole
36
running through the handgrip
2
into the part of the piston borehole
33
upstream of the valve face
32
. The sleeve
34
is connected in a rotationally fixed manner with a control element
37
, which is placed in a rotatable manner at the rear end of the piston borehole
33
. By turning the control element
37
, the sleeve
34
can be turned and the air passage in the region of the cross hole
35
can consequently be adjusted.
As indicated particularly in
FIG. 2
, a tube
38
is inserted into the compressed air borehole
36
at a distance from its inner wall, the compressed air borehole running through the handgrip
2
towards the piston borehole
33
, and the tube bordering an intermediate space
39
, ring-shaped in cross-section, between its outer wall and the inner wall of the compressed air borehole
36
. On each of the two ends of the tube
38
is a ring-shaped seal
40
and
41
respectively, through which the intermediate space
39
is sealed above and below with respect to the gun body
1
. Furthermore, through both seals
40
and
41
, the tube
38
is centrally held within the compressed air borehole
36
. The tube
38
is secured in an axial direction through a retaining ring
42
, which is screwed into an internal screw thread
43
provided at the inlet of the compressed air borehole
36
.
A recess
44
for the accommodation of a device
45
shown in
FIG. 1
for sensing and displaying the pressure predetermined through the valve system
29
is built into the handgrip
2
of the gun body
1
. This pressure-sensing and pressure display device
45
includes a digital display
46
inserted into the recess
44
and a pressure sensor, for example, a piezoelectric pressure sensor, not shown in detail, which is placed in a pressure gauge chamber
47
in the handgrip
2
. The digital display
46
and the pressure sensor are held by a cover plate
48
, equipped with a window, in the handgrip
2
, which is sealed using appropriate sealing elements to prevent the entry of liquid and dirt. Furthermore, in the handgrip
2
, a holding compartment
49
accessible from its rear is provided for a battery for supplying electricity to the pressure-sensing and pressure display device
45
.
The intermediate space
39
, sealed above and below through the two seals
40
and
41
, between the compressed air borehole
36
and the tube
38
, is connected via a first connection channel to the pressure chamber
28
downstream of the valve face
32
. This connection channel, in the design shown, consists of a first diagonal borehole
50
, shifted to the side of the mid-axis of the compressed air borehole
36
, and which runs from outside the handgrip
2
to the pressure chamber
28
, and connected in a middle region with the intermediate space
39
. The outer end of the borehole is sealed by a ball
51
, shown in
FIG. 1
, or by another appropriate sealing element. A second connection channel, shown in
FIG. 1
, runs from the intermediate space
39
to the pressure gauge chamber
47
. This connection channel
52
is expediently a second borehole
52
, which runs from the inlet of the compressed air borehole
36
diagonally to the pressure gauge chamber
47
. Through this arrangement, the second borehole
52
need not be sealed [by] a ball or the like, as in the case of the first connection channel. The first borehole
50
and the second borehole
52
are expediently designed as capillary boreholes with a diameter between 1 and 2 mm. This can prevent cleaning material and solvents respectively, used in cleaning the spray gun, and any dissolved lacquer particles, from reaching the pressure gauge chamber
47
and causing the impairment of the measuring accuracy there.
The compressed air is supplied to the valve system
29
through the tube
38
, which forms a compressed air supply channel
53
in the interior. On the underside of the handgrip
2
, a compressed air supply coupling
54
connected to the compressed air supply channel
53
is screwed into the compressed air borehole
36
.
While various descriptions of the present invention are described above, it should be understood that the various features could be used singly or in any combination thereof. Therefore, this invention is not to be limited to only the specifically preferred embodiments depicted herein.
Further, it should be understood that variations and modifications within the spirit and scope of the invention might occur to those skilled in the art to which the invention pertains. Accordingly, all expedient modifications readily attainable by one versed in the art from the disclosure set forth herein that are within the scope and spirit of the present invention are to be included as further embodiments of the present invention. The scope of the present invention is accordingly defined as set forth in the appended claims.
Claims
- 1. Paint spray gun comprising:a gun body having a handgrip; a paint nozzle attached to the gun body; an air nozzle placed around the paint nozzle; a compressed air valve placed within a piston borehole in the gun body for controlling compressed air supply to the air nozzle; a compressed air borehole having an inner wall and running through the handgrip of the gun body to the piston borehole; a pressure-sensing and pressure display device placed in the handgrip; and a tube placed in the compressed air borehole at a distance from the inner wall, wherein the tube forms an interior channel for the compressed air supply to a part of the piston borehole upstream of the compressed air valve and wherein the tube borders an intermediate space between the tube exterior and the inner wall of the compressed air borehole, the intermediate space being connected via a first connection channel with a pressure chamber placed downstream of the compressed air valve and via a second connection channel with a pressure gauge chamber in the handgrip allocated to the pressure-sensing and pressure display device.
- 2. Paint spray gun according to claim 1 wherein the first connection channel is a first connecting borehole shifted to a side of the compressed air borehole mid-axis, the first connecting borehole running from outside of the handgrip to the pressure chamber and being connected in a middle region with the intermediate space.
- 3. Paint spray gun according to claim 2 wherein the first connecting borehole is sealed on an outer end by a ball.
- 4. Paint spray gun according to claim 2 wherein at least a portion of the first connecting borehole is a capillary borehole.
- 5. Paint spray gun according to claim 1 wherein the second connection channel is a second connecting borehole which extends from an inlet of the compressed air borehole diagonally through the handgrip to the pressure gauge chamber.
- 6. Paint spray gun according to claim 5 wherein at least a portion of the second connecting borehole is a capillary borehole.
- 7. Paint spray gun according to claim 1 wherein a ring-shaped seal is placed on each end of the tube through which the intermediate space is sealed above and below with respect to the gun body.
- 8. Paint spray gun according to claim 1 wherein the tube is secured through a retaining ring located at an inlet of the compressed air borehole.
- 9. Paint spray gun according to claim 1 wherein a compressed air supply coupling connected to the channel is placed on an inlet of the compressed air borehole.
Priority Claims (1)
Number |
Date |
Country |
Kind |
101 35 104 |
Jul 2001 |
DE |
|
US Referenced Citations (4)