GB2215240A

GB2215240A - Paint spraying apparatus

Info

Publication number: GB2215240A
Application number: GB8804415A
Authority: GB
Inventors: Peter David Layley
Original assignee: Ford Motor Co
Current assignee: Ford Motor Co
Priority date: 1988-02-25
Filing date: 1988-02-25
Publication date: 1989-09-20
Anticipated expiration: 2008-02-25
Also published as: GB2215240B; GB8804415D0

Abstract

A paint spraying installation for use where the spraying is performed by a robot has the paint spray gun divided into two parts, i.e. an air feed unit 18 which incorporates all the air inlet connections and is permanently mounted on the robot arm, and a spray head 24 which incorporates the paint feed connections. The installation will include a number of spray heads, each dedicated to one paint colour and there is a quick-connection coupling so that the robot can pick up any one of the spray heads and couple it to the air feed unit to allow spraying to take place. <IMAGE>

Description

Paint spraying apparatus This invention relates to paint spraying apparatus, and particularly to apparatus used in robot-operated spray painting installations where one robot is required to spray paints of different colours. This arises for example in spray shops where car bodies are sprayed.

It is known to use a single spray gun permanently attached to the robot arm, and to exchange the paint supply feeding paint to the spray gun. With this arrangement, each time the paint colour is changed, it is necessary to purge the spray gun and the connecting hose downstream of the change-over point from all traces of the last colour.

This involves a substantial waste not only of paint, but also of a purging solvent.

According to the present invention, there is provided a paint spraying apparatus comprising a plurality of spray heads each with a paint feed connection, and an air feed unit, the air feed unit being adapted to mate with each spray head so as to provide an air supply to the spray head.

The air feed unit will normally be permanently connected to the arm of a suitable robot, and the spray heads (each connected to a supply of different coloured paint) will be mounted on a rack where they are each accessible to the robot. In this way, there is no need for purging between the spraying of different coloL, s as each colour has its own dedicated spray head.

The construction of the mating parts of the spray heads and the air feed unit is important to ensure that a tight connection can easily be made. The connection must transfer air from the air feed unit to the spray head to provide operating air for turning the paint flow on and off, to supply the shaping air horns, and for atomising the paint.

The spray head and the paint feed units preferably mate with each other through a tapered peg on one component which fits in a correspondingly shaped socket on the other component. The socket, which is preferably part of the spray head, may include a locking bar extending across a diameter of the socket, and the peg which will be on the air feed unit can then have a corresponding slot cut across a diameter which ensures that the spray head and air feed unit mate in the correct relative angular position. The air feed unit preferably includes a hook which engages with the bar and which is biased by air pressure to pull the two parts tightly together.

The operating airways between the air feed unit and the spray head are preferably arranged around the peg/socket connection and include tapered spigots projecting from one component into tapered sockets on the other component, with O-rings incorporated between the components to provide a tight seal.

The apparatus preferably also includes a rack for supporting a plurality of spray heads, and each head preferably has a tapered pin adapted to fit in a correspondingly tapered socket on the rack.

The invention will now be further described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a schematic plan view of a paint spraying apparatus in accordance with the invention; Figure 2 is a side view, partly in section, of a first embodiment of a paint spray head coupled to an air feed unit, all in accordance with the invention; Figure 3 is a section through the apparatus of Figure 2, on the line III-III; Figure 4 is a side view of a spray head in conjunction with a rack; Figure 5 is a perspective view of the mating face of a second embodiment of an air feed unit; and Figure 6 shows a view of the mating face of a spray head for use with the air feed unit of Figure 5.

Figure 1 shows a paint spray area for painting car bodies.

A car body 10 moves along a conveyor line 12 past a painting robot 14. The robot has an articulated arm 16 and an air feed unit 18 for a paint sprayer is permanently opted at the outer end of the arm 16. The ar 16 is fully articulated and can move for example between a position shown in full lines where it is able to pick up a spray head and a position shown in dotted lines where it is ready to commence spraying. The air feed unit 18 has an air hose 20.

A rack 22 is fitted in trie spray area. This is shown in the drawing at one side of the area, but in practice will be located above the position of the car body and offset towards the side on which the robot is. A number of spray heads 24 are mounted on the rack. Each spray head has a paint supply hose 26, and each head will be supplied with paint of one particular colour through its hose.

A quick-release coupling which will be described in more detail later enables the air feed unit 18 to be coupled to a spray head 24, so that the spray head can be picked up by the robot, and the robot can then spray the car with that particular colour.

The robot can be programmed to pick up any particular one of the spray heads 24, in accordance with the colour which is to be sprayed.

In this way, with a dedicated spray head for each paint colour, no purging of the equipment is necessary when changing from one colour to another. This avoids problems with paint waste and with undesirable pollution resulting from solvent vapour.

With this system it is necessary to take steps to ensure that the paint hoses 26 and the air hose 20 are properly managed to slake sure that they do not get tangled when changing from one spray head to another. This can however be dealt with by the use of a standard hose parking cabinet such as presently used for non-robotic paint spray installations with suitable modifications.

Figure 2 shows in side view an air feed unit 18 coupled to a paint spray head 24 which is only shown in outline. The spray head itself will be of conventional construction and will not be described in any detail. The air feed unit has three air connections 28, 30 and 32 which feed operating air, atomisation air and shaping horn control air respectively to the spray head 24. The air passes from the feed unit 18 to the spray head via tapered spigot and socket connections, one of which is shown in Figure 2 at 34. A projecting spigot 36 is fixed on the feed unit 18, and a corresponding socket 38 is formed in the mating part of the spray head. An 0-ring is held in a convenient place so that the joint is sealed when the parts are coupled together. There will be separate connections of this type for each of the three air feeds.The correct engagement of these three spigots and sockets will ensure that the spray head and air feed unit are properly angularly positioned relative to one another.

In Figures 2 and 3, the three air passages are positioned in one line, and in Figures 5 and 6, they are shown spaced around the mating face of the air feed and spray head units.

In order to couple a spray head to the air feed unit, a tapered peg 40 is formed on the feed unit 18, and correspondingly tapered socket 42 is formed on the spray head. A bar 44 (see Figure 6) is fitted in the spray head and extends diametrically across the socket 42. The peg 40 has a hollow core and a V-notch 46 which receives the bar 44. Inside the peg 40 is a hook 48 which is shown in Figure 2 in bold lines in its axial position where it engages over the bar 44, and in dotted lines in its inactive, insertion position where it allows the peg to move into the socket 42.

When the air feed unit 18 is properly positioned relative to the spray head, the hook 48 is pulled to the right in Figure 2. Because of a cam-shaped recess 50 in the hook body, the hook moves onto the centre line of the socket and engages the bar 44. Pulling the hook to the right pulls the air feed unit and the spray head firmly together and ensures that an accurate coupling is made. A supplementary compressed air feed is used to provide the power to move the hook 48 backwards and forwards.

The diametrical bar 44 and the V-shape of the notch 46 may be chosen so that location of the peg 40 fully in the socket 42 also ensures that the two parts are correctly angularly oriented.

In addition to this connection between the air feed units and the spray heads, it is important that the spray heads be properly secured on the rack 22 so that they can be properly presented for pick up by the robot, and reliably retained in place. For this to happen, the rack 24 has a series of tapered sockets 52 (see Figure 4) and the underside of each spray head 24 has a corresponding tapered peg 54. The peg 54 may have an annular groove 56, and a slidable plate 58 in the rack 22 can be moved backwards and forwards to either engage and grip the groove or to release the groove to allow the spray head to be lifted out.

The invention thus provides an arrangement which allows a robot to be programmed so that it can select a spray head with a particular paint colour, and where the actuation Ol the air feed unit/spray head coupling and the actuation of the spray head/rack coupling can all be programmed to ensure that the correct operating sequence is followed.

Claims

1. A paint spraying apparatus comprising a plurality of spray heads each with a paint feed connection, and an air feed unit, the air feed unit being adapted to mate with each spray head so as to provide an air supply to the spray head.

2. Apparatus as claimed in Claim 1, wherein the air feed unit is permanently connected to the arm of a suitable robot.

3. Apparatus as claimed in Claim 1 or Claim 2, wherein the spray heads (each connected to a supply of different coloured paint) are mounted on a rack where they are each accessible to the robot.

4. Apparatus as claimed in any preceding claim, wherein the spray head and the air feed units mate with each other through a tapered peg on one component which fits in a correspondingly shaped socket on the other component.

5. Apparatus as claimed in Claim 4, wherein the socket is part of the spray head and the peg is part of the air feed unit.

6. Apparatus as claimed in Claim 4 or Claim 5, wherein the socket includes a locking bar extending across a diameter of the socket, and the peg has a corresponding notch cut across a diameter.

7. Apparatus as claimed in Claim 6, wherein the peg includes a hook which engages with the bar and which is biased by air pressure to pull the two parts tightly together.

8. Apparatus as claimed in any one of Claims 4 to 7, wherein operating airways between the air feed unit and the spray head are arranged around the peg/socket connection and include tapered spigots projecting from one component into tapered sockets on the other component, with O-rings incorporated between the components to provide a tight seal.

9. Apparatus as claimed in any preceding claim, including a rack for supporting a plurality of spray heads, wherein each head has a tapered pin adapted to fit in a correspondingly tapered socket on the rack.

10. Paint spraying apparatus substantially as herein described with reference to the accompanying drawings.