FR2587631A1 - DEVICE FOR ADJUSTING THE FLOW OF AIR IN A PAINT GUN - Google Patents

Abstract

THE DEVICE OF THE INVENTION INCLUDES: CONTAINED IN A VALVE BODY 11 PROVIDED WITH PASS-THROUGH HOLES 16, 17, AN INLET DUCT 14 PROVIDING AT ONE OF ITS ENDS A FITTING 19 FOR CONNECTING TO A SUPPLY PIPE OF THE COMPRESSED AIR AND AN OUTLET DUCT 15 OPENING INTO THE CENTRAL DUCTING OF THE GUN; -A ADJUSTING BODY 8 PROVIDED WITH A NOZZLE 12 MOUNTED ON THE VALVE BODY 11 AND LIKELY TO MOVE AXIALLY SO AS TO CLOSE OR OPEN PROGRESSIVELY THE PASSAGE OF THE AIR THROUGH THE SAID PASSAGE HOLES 16, 17 OF WHICH THOSE 16 , RELATING TO THE SAID INPUT DUCT 14, ARE OF DIFFERENT DIAMETERS; -A CHAMBER 27, PUTTING IN COMMUNICATION DUCTS 14, 15 AND SEALED IN A WATERTIGHT MANNER BY THE TIP 12 IN THE HANDLE 3 OF THE GUN, IN THE said CHAMBER 27 BEING PLACED THE VALVE BODY 11.

Description

- 1 -

  The present invention relates to a device for

  air flow measurement in a spray gun.

  We know that paint guns are

  using compressed air and are intended to spread nebulized paint over a

any surface.

  For this purpose they generally include, in outline, a body that extends into a handle

  inside which there is a central

  the. The latter develops from the lower end

  from the handle to a suitably

placed on the body of the pistol.

  In addition, a paint supply line terminates near the sprayer, the paint being con

  held in a tank connected to the spray gun.

  When we have to operate the latter, we connect to the central pipe an air supply pipe

  compressed provided by a common compressor. By acting

  venably on a trigger lever we open the air passage to the sprayer, dosing simultaneously the output of

the painting of the latter.

  The operation of the spray guns described below

  in broad outline is usually based on

  the principle that the high speed achieved by air com-

  award-winning sprayer spreads the

paint finish.

  It should be noted that the operating conditions

  and the performances required of the pistols mentioned above may

  vary depending on, for example, the type of

  painting used. and / or the kind of varnishing that we

sire get.

  In order to meet these requirements,

  paint are fitted with suitable adjustment devices

ge.

  One of these devices which has a remarkable importance

  the effects of the present invention is that which

  sets the air flow rate to the sprayer. This device is of fundamental importance because, for

  its intermediary, we can adjust the power of the launcher

  as well as the nebulisation of the paint, these characteristics

  are crucial for the success of

of the opening.

  Many devices are currently being

  adjustment of the air flow which differentiate

  each other because of their positioning on the gun and the system adopted in the setting of

the influx of compressed air.

  Some are interposed between the pipe

  supply and the central pipe of the pistol

  paint, and they comprise a cylindrical valve body

  in which an inlet pipe is obtained and

an outlet pipe.

  The air from the supply pipe passes from one line to the other through a series of through-holes provided in the valve body, corresponding to which

  extends an annular chamber delimited by a mouthpiece

linked to the same valve body.

  The tip is further provided with a shoulder intended to plug the holes relative to the outlet pipe, to a greater or lesser degree depending on the positioning.

  reciprocal tip-valve body. In this way, the

  air flow to a central pipe can easily be done by simply screwing or unscrewing

of the mouthpiece.

  - 3 - Adjustment devices of the type described above

  have shown themselves to be very effective in

  fulfillment of the tasks entrusted to them. Toute-

  times, they have some disadvantages related to the fact that they must necessarily be arranged outside

  of the pistol grip, in order to allow the maneuver

true of the mouthpiece.

  This causes a first disadvantage determined by the fact that, during the operation of the gun, the pain

  nebulized and suspended in the air can (which is

  often has to infiltrate the interstices formed by

  the engagement valve-tip body, where it

  gradually. This causes a difficult operation

  the tip and, in the worst case, even his stop

plete.

  In addition, it should be noted that the external positioning of the handle also causes the imbalance of the whole gun. As a result of this the operator has to make some effort of the hand in order to hand

  hold the spray of the paint in the desired direction.

  Another disadvantage encountered in the devices illustrated above must be attributed to the fact that the passage holes relative to the outlet pipe are plugged simultaneously and of the same degree by the shoulder provided in the nozzle, which results in inaccuracies of remarkable operation when one has to perform

  adjustments on small airflows.

  In this situation, the purpose of the present invention

  is to overcome the disadvantages mentioned above

  by means of a device which may be contained, in respect of its essential parts, within

  the handle of the paint gun.

  Another object of the present invention is that this positive device may allow a much better air flow adjustment, especially when it is necessary to regulate the influx of

very small amounts of air.

  Another object of the invention is to provide an arrangement

  an inexpensive realization by industrialists

sector.

  These and other goals that will emerge more clearly

  of the following description are essentially

  dyed by a device for adjusting the air flow rate in a spray gun, of the type comprising an air duct

  at one end of which is provided a

  connecting cable to a compressed air supply pipe

  m, an outlet duct opening into the central duct of the gun, said ducts being formed in a valve body provided with through holes arranged in correspondence of the respectively opposite ends of said ducts, a chamber which communicates said ducts for the passage of the fluid, as well as

  adjusting member consisting of a nozzle mounted on the

  said valve body and capable of moving axially-

  on the latter so that it closes or progressively opens the passage of air through said step holes

  wise, characterized in that said chamber which

  communication the pipes is obtained in the handle of the

  pistol and is engaged in a sealed manner by the said

  end, said valve body being housed inside the

- said chamber:.

  Other features and benefits will emerge

  more clearly from the following detailed description of a

  preferred but not exclusive embodiment of a

  air flow adjustment device in a paint spray gun.

  5, with reference to the accompanying drawings given by way of non-limiting example only, in which:

  - Figure 1 shows, in perspective, a spray gun

  comprising the device according to the present invention; FIG. 2 shows, partially in section, the device

  tif subject of the present invention.

  Referring to these figures, we have globally

  identified in 1 a paint gun known per se and

  tional. In outline, it comprises a body 2 which extends into a handle 3 and which ends with a sprayer 4 oriented in the horizontal direction. There is further provided a paint reservoir 5 releasably connected

  at the lower part of the body 2 by a hook-and-loop connection

  6. A control lever 7 is pivoted on the body 2; by this lever we open the passage from the air to the sprayer 4

  regulating at the same time the influx of the painting & the latter.

  The spray gun 1 further comprises a device

  tif for the adjustment of the air flow indicated generally in 8 and connected to the handle 3 at its lower part, and

  auxiliary adjustment devices, including the

  9 are connected to the rear of the

body 2.

  A central pipe 10 which is visible only partially in the appended figures, extends inside the gun 1 from the lower end of the handle 3

to the sprayer 4.

  According to the present invention and by referring

  2, the air flow control device 8 comprises a valve body 11 of cylindrical section, on which is provided a nozzle 12 associated with

  this one by threaded engagement 13.

  In more detail, the valve body 11 has an inlet duct 14 and an outlet duct 15

  coaxially in it and extending in accordance with

  oppositions. In the vicinity of the opposite ends of the pipes 14 and 15, relative to each of these, there are provided respective through-holes 16 and 17, aligned in the same diametral plane and extending radially in

the valve body 11.

  In an original way, the holes 16 have diameters

  slightly different from each other, which means

  discusses the benefits that will be clarified later.

  On the free end of the pipe 15 isprévoit a thread 18 by which the device 8 in question is connected

  to the central pipe 10 of the gun 1.

  In correspondence of the free end of the pipe 14

  there is a connecting connection 19 comprising a hexagonal head

  19a and a threaded portion 19b. It is on this last

  We are going to screw a pipe for the supply of compressed air, which is not represented here being of known type

and conventional.

  It is provided in an original way that the tip 12 extends

  on the valve body 11 at a position between

  the holes 16 and the connector 19. At its outside it is

  in order to define a cylindrical surface 20 on the

  which is arranged a sealing ring 21. -1 at the respective ends of the cylindrical surface

  the tip 12 has a conical portion 22 and an annular portion

  crenellated nipple 23, which is superimposed on the hexagonal head

  19a, as shown in Figure 2.

  In its interior and in correspondence of the resting end to the conical surface 22, the tip 12 is provided with an annular working surface 24 of calibrated diameter so as to marry in a substantially sealed manner

the valve body 11.

  Still inside the nozzle 12 is provided another annular surface 25 which extends substantially between the threaded coupling 13 and the annular portion 23. A sealing ring 26 disposed on the valve body

It acts on the surface 25.

  Advantageously, when the device 8 is connected to the

  spray gun 1, the nozzle 12 engages in a chamber

  cylindrical sleeve 27 formed at the base of the handle 3, fai

  projecting from it in the area of the annular portion

crenellated ground 23.

  Likewise, the valve body 11 extends inside the cylindrical chamber 27 engaging its threading 18 in

  the free end of the central pipe 10.

  After the above description, we will now

  to gloss the operation of the device according to the present invention.

  Compressed air from the feed pipe

  mentioned above, runs through the inlet pipe 14 and out of the holes 16 relative thereto. In this way

  the air passes into the cylindrical chamber 27 isolated

  waterproof from the outside thanks to the sealing ring 21

  and then returns to the valve body it correspon-

  holes 17 relating to the outlet pipe 15.

  After that, the air passes to the central pipe 10,

  which brings it in a known and conventional way to the pulverulent

riser 4.

  The adjustment of the inflow of air to the central duct

  tral 10 is performed properly acting on the por-

  annular 23 which allows the screwing or unscrewing of the tip 12, which will cause the axial displacement of this - 8 -

  last in relation to the valve body 11. In this manner,

  re the annular surface 24 of the tip 12 can clog

  of a greater or lesser degree the holes 16 according to the po-

sitioning the tip itself.

  Advantageously, the difference between the diameters of the holes 16 makes it possible to adjust optimally also the passage through them of very small quantities

  air. Indeed, it is obvious that if we act on the

  end 12 so as to gradually limit the passage of air, we will first obtain the total closure of the hole

  the smallest, which will be followed by the closure of

  very many holes in succession, which will obviously lead to

  finer and more precise adjustment of the air.

  Attention is also drawn to the fact that the device in question is substantially completely contained in the handle 3 of the pistol 1, from which it exits exclusively in correspondence of the connector 19 and the annular portion 23. eliminated the disadvantages

  traditional control devices

described were submitted.

  Finally, the device in question appears execution

simple and inexpensive.

  The invention is susceptible of numerous modifications

  tions and variants which all fall within the scope of protection of the invention itself. All the details

  may be replaced by technically equi-

  valent. The shapes, dimensions and materials used

  may be of any kind, as

your. - 9 -

R E V E N D ICATIONS

  1. Device for regulating the flow of air in a pistol

  paint type (1), of the type comprising an

  at one end of which is provided a connection connection (19) to a compressed air supply pipe, an outlet pipe (15) opening into the central pipe (10) of the gun , said ducts (14, 15) being formed in a valve body (11) provided with passage holes (16, 17) arranged in correspondence with the respective opposite ends of said ducts (14,), a chamber (27) which communicating said conduits for the passage of fluid, and an adjusting member (8) consisting of a tip (12) mounted on said

  valve body (11) and able to move axially-

  on the latter so that it closes or progressively opens the passage of air through said passage holes (16, 17), characterized in that said chamber (27) which communicates the conduits (14, 15) is obtained

  in the handle (3) of the gun (1) and is engaged by

  sealed by said tip (12), said valve body

  (11) being housed inside said chamber (27).

  2. Device according to claim 1, characterized in

  the passage holes (16) relating to the said

  input diameter (14) are respectively of different diameters

  feralized and arranged along the same transversal plane

  said valve body (11), so that they are closed in succession by said nozzle (12) during the steps of

adjustment of the air.