A hand-operated electrostatic spraygun comprises a gun body, a pistol tube of insulating material, a handle, an insulation-clad high-voltage generator and a connection for paint delivery and is contructed such that the gun is particularly small, lightweight and can be effortlessly held in the hand. The gun body, preferably composed of aluminum, is an essentially cylindrical body which comprises the connection for paint delivery in the region of its forward end adjacent its forward face. The pistol tube, preferably formed of plastic, is secured to the forward face of the gun body in a manner to be secured against twisting and comprises a clover leaf-shaped cross section having two to four "leaves". The high-voltage generator is secured at the rear region of the end body to the underside thereof, whereby the cladding of the high-voltage generator is shaped as a pistol grip and forms a handle for the spraygun.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to a hand-operated electrostatic spraygun 
which comprises a gun body, a pistol tube of insulating material, a 
handle, an insulation-clad high-voltage generator and a connection for 
paint delivery. 
2. Description of the Prior Art 
Hand-operated electrostatic sprayguns of the type generally set forth 
above, i.e. having a high-voltage generator located in the pistol barrel, 
are commercially available in a variety of embodiments. The high-voltage 
generator is usually accommodated in the pistol tube or in the handle. It 
is also known to attach the high-voltage generator between the pistol tube 
and the lower-free end of the handle as a separate component. All of these 
apparatus, however, share the disadvantage that, despite general efforts 
to the contrary, they are comparatively unfavorable in terms of size, 
weight and center of gravity as tools to be held in the handle for a long 
period of time. 
SUMMARY OF THE INVENTION 
It is therefore the object of the present invention to provide 
hand-operated electrostatic sprayguns of the type generally set forth 
above which are smaller, lighter in weight and easier to hold than 
apparatus heretofore known. 
The above object is achieved, according to the present invention, in a 
hand-operated electrostatic spraygun having the general structure 
mentioned above, and in which the gun body is an essentially cylindrical 
body which comprises the connection for the paint delivery at the bottom 
of its cylindrical jacket, forward of the pistol grip and trigger as 
viewed in the spraying direction, in which the pistol tube is secured to 
the front of the gun body against twisting and comprises a clover 
leaf-shaped cross section having two to four "leaves", and in which the 
high-voltage generator is secured in the rear region of the gun body in 
the pistol grip below the cylinder jacket, and the cladding of the 
high-voltage generator is shaped such that it forms the handle or pistol 
grip of the spraygun. 
According to the invention, therefore, the actual gun body is composed of a 
basically cylindrical component that is small and can be easily held, 
particularly because only the forwardmost portion of the gun body is 
subjected to the paint pressure, this being of great significance 
particularly given sprayguns operating with high paint pressure. The 
pistol tube is secured to the front end of the gun body, whereby the 
cross-sectional shape selected yields a substantial weight reduction 
because all material which is not absolutely necessary has been removed. 
In other words, the tube walls essentially surround only the channels 
extending through the pistol tube. Also contributing significantly to the 
weight reduction is that no separate handle is provided, rather the 
high-voltage generator, whose required insulation cladding is designed as 
a pistol grip, represents the handle. These features of the invention 
produce both a size reduction and a weight facilitation of the 
hand-operated spraygun, as well as a center of gravity that is very 
beneficial in terms of location of the center of gravity, this being of 
particular significance for holding the spraygun without tiring. This 
design thereby leads to a simple manufacture and assembly of the spraygun 
and, on the basis of slight modifications, the spraygun can be employed as 
a compressed air gun, as a high-pressure paint spraygun without compressed 
air and as a high-pressure paint spraygun with additionally supplied 
compressed air.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring to the drawing, the illustrated paint spraygun comprises a gun 
body 10, preferably constructed of aluminum, which essentially has the 
shape of a cylinder. A pistol tube 11, preferably composed of plastic, is 
screwed onto the front end of the gun body 10, the central portion of the 
pistol tube having a cross section in the form of a three-leaf clover in 
accordance with FIG. 2. Secured by screw connections in the rear region of 
the gun body 10 are, at the underside thereof, a high-voltage generator 12 
having a plastic coating or cladding and a compressed air delivery tube 13 
of metal which extends parallel to the high-voltage generator 12. Finally, 
a trigger 14 is hinged to the gun body 10. The paint spraygun is therefore 
composed of five basic elements, namely the gun body 10, the pistol tube 
11, the high-voltage generator 12, the compressed air delivery tube 13 and 
the trigger 14. These main elements shall be described in detail below. 
The gun body 10 has an elongate channel 15 therethrough in which a control 
member 16 is displaceably disposed and is seated on a paint valve stem 
with extends axially through the control channel 15. The control member 16 
comprises a rigid control flange 16a and a control flange 16b, partially 
displaceable thereon. Coil springs 18 and 19 bear against opposite ends of 
the control member 16 and define the position of the control member 16 on 
the valve stem 17. The control channel 15 is in communication with an 
obliquely-extending air connecting channel, namely in the region of the 
control member 16. The air channel 20 is continued in two air channels 21 
extending towards the forward end of the gun body 10, only one of these 
two channels 21 being visible in the drawing. The two channels 21 can be 
separately opened and respectively, closed relative to the air connecting 
channel 20 by way of screw plugs 22. The gun body 10 further comprises a 
paint connection 23 having a paint delivery channel 24 which discharges 
into the control channel 15 close to the forward end face of the gun body 
10. Finally, the gun body 10 comprises a bore which likewise proceeds to 
its forward end face, a high-voltage lead 25 being accommodated in this 
bore. The pistol tube 11 includes a centrally disposed paint channel 26 
and a valve stem 27 extends through the paint channel 26. When the pistol 
tube 11 is secured to the gun body 10, the paint channel 26 communicates 
with the control channel 15 and the valve stem 27 is tightly connected to 
the valve stem 17. A paint valve 28 is located at the forward end of the 
valve stem 27. The paint channel 26 continues beyond the paint valve 28 up 
to the spray nozzle 29. Also extending through the pistol tube 11 are two 
air channels 30 and 31, as best seen in FIG. 2, which continue the two air 
channels 21 of the gun body 10 when the pistol tube 11 is in place on the 
gun body 10, whereby the one air channel 30 discharges before the spray 
nozzle 29 and supplies the atomizer air for the air jets 32, whereas the 
air channel 31 supplies the two air horns 33 with control air. Finally, a 
high-voltage cable 34 extends through the pistol tube 11, the cable 34 
being electrically connected to the high-voltage cable 25 of the gun body 
10 and supplying the sprayer electrode 36 with electrical energy via a 
high-value resistor 35. The pin referenced 37 serves to define the desired 
rotational position of the pistol tube 11 is emplaced and mounted on the 
gun body 10. 
The high-voltage generator 12 has its one end screwed into the gun body 10, 
whereby its electrical output then contacts the high-voltage cable 25 
extending through the body 10. At its other end, the high-voltage 
generator 12 is connected to a low-voltage supply cable 38. The 
high-voltage generator 12 essentially comprises a transformer, a 
high-voltage cascade or voltage multiplier, and an insulating cladding, 
whereby the cladding, as already mentioned, has the shape of the pistol 
grip or handle. 
The compressed air delivery tube 13 has its one end screwed into the gun 
body 10 and has a connection at its other end 13a for a compressed air 
supply line. The tube 13 extends at the rear of the high-voltage generator 
12 and is preferably releasably connected thereto for stabilization. The 
arrangement is undertaken such that the high-voltage generator 12 and the 
compressed air delivery tube can be readily grasped by the hand of the 
operator. 
As already mentioned above, the trigger 14 is hinged to the gun body 10 and 
comprises a switch element 39 that can be hinged away, the switch element 
39 cooperating with a proximity switch 39', for example a reed switch, 
located in the high-voltage generator 12 for connecting the high-voltage 
generator to the high-voltage lead 25. 
The described electrostatic spraygun operates in the following manner. When 
the trigger 14 is actuated by the operator, then the movable control 
flange 16b is first displaced (towards the left on the drawing), with the 
consequence that the compressed air adjacent in the compressed air 
delivery tube, while traversing the bore 15, proceeds through the bore 20 
to the two compressed air channels 21 and continues therefrom via the 
channels 30 and 31 to the air jets 32 and the air horns 33. As soon as the 
control flange 16b strikes the control flange 16a, the entire control 
member 16 is displaced (towards the left on the drawing), with the 
consequence that the paint valve 28 is opened via the interconnected valve 
stems 17 and 27 and the paint emerges from the sprayer nozzle 29 as a 
spray jet. At the same time the switch element 39 approaches so close to 
the proximity switch (not shown) in the handle including the high-voltage 
generator 12 that the proximity switch is operated and the sprayer 
electrode 36 is supplied with spray current from the high-voltage 
generator 12 via the high-voltage cables 24 and 34 and the high-value 
resistor 35. When the trigger 14 is released, the operation then proceeds 
in a correspondingly reverse manner, i.e. the paint feed is inhibited 
first and then the air feed is inhibited. The ratio between the atomizer 
air and controlled air can be arbitrarily modified by turning the screw 
plugs 22, and the trigger path or, respectively, the trigger resistance 
can be varied by turning the screw 40. When the switch element 39 is 
hinged away, then spraying can be carried out in a purely mechanical 
manner, i.e. without an electrostatic field. 
The spray gun body 10 can also be fabricated of plastic, but metal, 
particularly lightweight aluminum in this case, is preferable because the 
body comprises a number of screw connections. Essential, however, is that 
the paint feed 23, 24 is located close to the connection of the pistol 
tube 11 to the gun body, particularly given sprayguns operating with high 
paint pressure because only an insignificant portion of the gun body is 
then subjected to the paint pressure and the majority of the body 10 can 
be fashioned with thin walls for the sake of saving weight. Also of 
significance for the sake of saving weight is that the pistol tube 11 has 
the cross section that may be seen from FIG. 2 or a significant portion of 
its length, i.e. those portions of the two walls that are not absolutely 
necessary have been eliminated. Of significance, finally, with respect to 
saving weight and reducing size is that the cladding of the high-voltage 
generator itself represents the handle, in particular contrasting the 
heretofore traditional structure whereby the high-voltage generator (with 
its cladding) was introduced into a hollow handle. Plastic can likewise be 
selected for the compressed air delivery tube and the trigger 14, but 
lightweight metal is preferable. 
The described electrostatic paint spraygun is distinguished by a structure 
that guarantees a simple manufacture of the components and a simple 
assembly. The particular advantage, however, is that the gun is small, 
sleek and significantly lighter in weight than comparable 
commercially-available devices. Added thereto is a very favorable center 
of gravity, this leading overall to the fact that the operator does not 
tire even given long-duration use of the paint spraygun with the 
integrated high-voltage generator. 
The illustrated and described exemplary embodiment is a matter of a paint 
spraygun having compressed air atomization and auxiliary control air. The 
spraygun, can also be designed as an airless high-pressure gun, whereby 
the compressed air tube 13 is eliminated and the sprayer nozzle 29 is 
replaced with a corresponding high-pressure nozzle. If an even greater 
saving of weight is to take place in this case, the pistol tube 11 can be 
additionally specifically designed such that the air channels 30 and 31 
are eliminated and the cross section then designed as a "two-leaf" clover 
or, respectively, as a double barrel structure. A paint spraygun 
constructed in accordance with the present invention is particularly 
suitable for guns working with high paint pressure and auxiliary 
compressed air, whereby essentially no modifications are necessary over 
the exemplary embodiment, whereby modifications would at most affect only 
the design of the air discharge openings at the forward end of the pistol 
tube. 
Although we have described our invention by reference to particular 
embodiments thereof, many changes and modifications of the invention may 
become apparent to those skilled in the art without departing from the 
spirit and scope of the invention. We therefore intend to include within 
the patent warranted hereon all such changes and modifications as may 
reasonably and properly be included within the scope of our contribution 
to the art.