DEVICE FOR APPLICATION OF FLUID

Abstract: A device for the application of a fluid on a surface and intended to be mounted as a tool on a holder which is adjustable between different positions and directions. The device comprises feeding means (4) for the supply of one or several pressurized fluids to at least two nozzles (38-41) mounted on the tool for discharge of said fluid. The device comprises valve means (26) associated with each nozzle (38-41) for separate control of the supply of fluid from the feeding means (4) to each nozzle through a channel (29, 36).

Description: DEVICE FOR APPLICATION OF FLUID The present invention relates to a device for the application of a fluid according to the preamble of claim 1. A device of the current type is in practice implemented as a rotatable spray gun which has a number of spray nozzles and is designed to be mounted on a control device in the shape of a robot. Spray guns are used when fluids, such as gases, liquids or plastic material, are to be sprayed or extruded onto a surface. One example of a field of application is in the automobile industry when bodies are to be surface treated or joints sealed. Other fields of application are naturally also possible, naturally. When the gun is used, it has to be positioned carefully in relation to the surface where the material is to be applied. Conventional spray guns are usually furnished with one single nozzle having a fixed application direction. Redirection of the nozzle must then be done by turning the whole gun, something which takes time and can cause problems with accessibility in confined spaces. Redirection of a spray gun places high demands on a robot's control instructions to achieve correct application with a high precision. Rotating spray assemblies with several nozzles are previously known from, for example, WO 80/02278. This publication, however, shows a spray assembly with simultaneous feed to all the nozzles, which severely limits the range of use of the assembly. One object of the present invention is to improve the accessibility during, for example, extrusion or spraying, which then can proceed without the necessity of a tool change. A further object of the present invention is to reduce the adjustment times which are necessary for an adjustment from a first spraying direction to a second spraying direction. A further object of the present invention is to enable a changeover between different process steps, for example between spraying and extrusion, without an intervening tool change. These objects are achieved with a device according to the present invention, the features of which are disclosed in the enclosed claim 1. By means of the possibility to switch between different nozzles, the extent of utilization of the device can be increased, which leads to reduced process times and, therewith, reduced production costs. The invention will be described in greater detail in the following by way of several embodiments whilst reference is made to the accompanying drawings, in which Fig. 1 in a perspective view shows the outer construction of the device according to the invention in an example with a first nozzle head, Fig. 2 shows a second example with a partially sectioned longitudinal cross-section, where the device has a second nozzle head, and Fig. 3 shows on a larger scale a longitudinal cross-section through a module of a swivel means belonging to the device. As is evident from the drawings the device for application of a fluid is designed as a gun tool which comprises five main components, namely an adapter 1 which serves to connect the gun with a robotic arm (not shown), a swivel means 2, which is capable of transmitting a rotary movement, a connection 3 to a feeder means 4 (see Fig. 2) for a fluid, such as a gas, liquid or a plastic material, a positioning lance 5 and a head 6 having a number of spray- or extrusion nozzles. The construction and respective function of the different main components will be described further in the following. The adapter is constructed to be mounted on a robotic arm of any known type directly or via an intermediate adapter. A robotic arm can usually perform movements in six degrees of freedom, i.e. motion in three directions x, y, z, rotation about a first and a second axis y, z, which are perpendicular to each other and which are at a right angle to the longitudinal direction of the robotic arm, and a rotation about a third axis x which runs in the longitudinal direction of the robotic arm. The adapter 1 transmits the rotation about this third axis either because the adapter is rigidly rotated or because a shaft 7 located in the adapter is rotated with respect to the adapter. The shaft located in the adapter is connected to a shaft 8 rotatably held in the swivel means 2. This shaft can be an integral continuation of the shaft 7. In this case, the shafts 7 and 8 consist of a shaft made in one piece, which by means of a locking pin 9 is rotationally fixedly connected to the adapter 1 and arranged to be rotated by the robotic arm. The swivel means 2 is outwardly limited by a housing 10, which has an outer mantle surface 11 and an inner cylindrical wall 12 and two end surfaces 13 and 14. The mantle surface of the housing is substantially cylindrical, but also other shapes of the mantle surface of the housing are of course possible. A first through channel 15 is arranged through the mantle surface of the housing. The through channel has an inlet opening 16 and an outlet 17. The inlet opening connects the through channel to a supply channel 18, through which the material to be extruded or sprayed is furnished from the feeder means 4 for the plastic material. The supply channel 18 is formed in the connection means 3, which connects the swivel means 2 to the feeder means 4. The outlet 17 is connected to a channel 19. This channel runs along the inner wall 20 of the housing 10 and connects the first through channel 15 with a number of second through channels 21. The second through channels each have an inlet opening 22 and an outlet 23. The channel 19 is preferably shaped like an annular groove in a bearing ring 24 arranged on the shaft 8. The groove can, alternatively, be milled in the inner wall of the housing. The groove does not necessarily have to be closed, that is be ring-shaped; instead, it is also conceivable to arrange the groove as a branched groove with one or more endings. Each outlet 17 connects the respective through channel 21 with an inlet channel 25 to a valve means 26. The valve means is manouverable and can be opened and closed in some known manner. The valve means consists of an outlet channel 27 which is connected to an inlet 28 of a channel 29 running inside the housing, preferably substantially along the longitudinal axis of the housing which coincides with the longitudinal axis A of the gun. The channel 29 is, in turn, connected to a channel 30, which runs between the inner wall 20 of the housing and the channel 29. The channel 30 has an outlet 31, which is connected to a channel 32 which runs annularly around the shaft 8. The channel is partly limited by the peripheral surface 33 of the shaft. The channel is further limited by parts of the structure 34 which rotatably hold the shaft 8 in the housing 10. The channel 32 is connected to an inlet 34 which leads to a longitudinal channel 35. This channel iε, in turn, possibly connected, which is the case in the shown examples, via an extension channel 36 and the corresponding channel 42 in the head 6, to an outlet 37 in a spray- or extrusion nozzle 38. The extension channel 36 is formed in the lance 5 which is of modular type and can be easily exchanged for a lance of a length which is suitable for the usage of the tool. The lance 5 is attached to the head 6 and the swivel means 2 in some known manner so that the head can also be modularly exchanged for heads with other nozzle types, dimensions or locations. Since the channel 32 runs annularly around the shaft 8, the outlet 31 will be in constant communication with the channel 32 during rotation of the shaft 8. No interruptions of the supply of material will take place on account of the rotation. The spray gun has at least two, in the shown example three spray or extrusion nozzles 38-41. To ensure the functioning of the gun, each of the nozzles has a channel between the common channel 19 and the nozzle. Each such channel is arranged in a corresponding manner as the described channel to the first nozzle 38. To each channel there is also arranged a manouverable valve means. This implies that each nozzle can be opened and closed independently of the others. For this reason, it is possible to open one or more nozzles at the same time. The bearing structure preferably comprises a number of ball bearings which run in their own grooves milled in the shaft. A number of annular channels 32, 42, 43, one for each nozzle, is formed by sealing means 44 inserted between the housing and the shaft, which sealing means are in contact with the periphery of the shaft. These means are preferably fastened in the housing, but it is also conceivable that the rotation takes place against the inner wall of the housing. The channel 19 can also be formed through a means 45 inserted between the shaft and the housing. The housing is closed axially by a first and a second end piece 46, 47. The head of the spray gun is, as has been mentioned, arranged with at least two, for example three, spray- or extrusion nozzles, each of which in the shown examples is aiming in different planes and/or directions. According to the example of Fig. 1, a nozzle is preferably aimed substantially in the direction of the axis A, i.e. in the x direction. A second nozzle 38 is preferably aimed substantially perpendicular to the longitudinal axis A, i.e. in the y direction. A third nozzle 40 is aimed in the x/y plane and preferably forms an angle of 40°-50° with the x axis. In the example shown in Fig. 2, two nozzles 38, 39 are illustrated, of which one is aimed axially and the other perpendicular to the longitudinal axis A. A third nozzle is hidden behind the head and is, for example, aimed perpendicular to the other two nozzles 38, 39 or forms a smaller or larger angle to one of the other nozzles. The valve means 26 are, for example, constructed as shown in Fig. 2 and 3 in the form of a ball valve with a valve body in the shape of a ball 50 which is urged by a spring 51 to a closed position onto a seat. Opening or closing of the valve is performed using a control means, in the shown example in the form of an axially movable needle 52 which is moved by pneumatic means, for example an air controlled piston 53, movable within an air cylinder 54, which through a not shown air hose is connected to a pneumatic control device. Each valve means 26 with the corresponding control means 52, 53, 54 and channels 25, 27 is also assembled into a module which is easily replaceable. The invention is not restricted to the previous description nor to the examples shown in the drawings, but may be varied within the scope of the appended claims. For example, two or more nozzles can have the same direction of action. The feeding means for the incoming fluid can have more than one channel for the supply of different fluids. For example, air can be added in a separate channel all the way up to a special nozzle which has double nozzle holes, e.g. one for each fluid. For each fluid a separate annular channel is required before the valves. Instead of a robotic arm, the gun can be mounted on other types of movable holders for automated adjustment between different positions and/or process steps. The valve means 26 can alternatively be mounted separated from the swivel means 2 and the gun. The number of nozzles can be two or more.

Claims: CLAIMS : 1. Device for the application of a fluid on a surface and intended to be mounted as a tool on a holder which is adjustable between different positions and directions, wherein the device comprises feeding means (4) for the supply of one or several pressurized fluids to at least two nozzles (38-41) mounted on the tool for discharge of said fluid, characterized in that the device comprises at least one valve means (26) associated with each nozzle (38-41) for separate control of the supply of fluid from the feeding means (4) to each nozzle through a channel (28, 29, 30, 32, 36) running between each valve means and the corresponding nozzle. 2. Device for the application of a fluid on a surface and intended to be mounted as a tool on a holder, which is adjustable between different positions and directions and arranged to transmit a rotating movement to at least one nozzle (38-41) on the tool, characterized in that the tool comprises a swivel means (2) which has a housing (10) to which the feeding means (4) is connected and a shaft (8) which, on the one hand is rotatably held in the housing and, on the other hand carries said nozzle or nozzles, at least a first channel (15) which forms a passage for said fluid through the housing to the rotatable shaft, at least one second channel (19) for the supply of fluid from said first channel to the rotatable shaft, irrespective of its rotary position, and at least one third channel (22, 27, 29, 31, 35, 36) arranged in said shaft for the supply of said fluid from said second channel to said nozzle or nozzles. 3. Device according to claim 2, characterized in that said second channel comprises an annular channel (19) which runs in a direction perpendicular to the longitudinal axis (A) of the shaft (8). 4. Device according to claim 1 or 2, characterized in that the number of nozzles (38-41) is three and that each nozzle is aimed in different directions. 5. Device according to claim 2, characterized in that on the housing (10) there is arranged at least one valve means (26) for controlling the supply of fluid from the feeding means (4) to the respective nozzle (38-41) and in that said valve means is connected between said second channel (19) and said third channel (22, 27, 29, 31, 35, 36). 6. Device according to claim 2 or 5, characterized in, that said second channel (19) consists of an open annular channel, open towards at least a part of the inner circumferential surface (12) of the housing. 7. Device according to claim 5, characterized in that said third channel (22, 27, 29, 31, 35, 36) comprises an annular channel (32) for each valve means (26) and nozzle (38-41) arranged at the transition between the housing (10) and the shaft (8) , open along at least a part of their circumference. 8. Device according to claims 2 or 5, characterized in that the tool is modularly constructed comprising one module for the swivel means (2), one module for each valve means (26), one module for a nozzle head (6) in which said nozzles (38-41) are positioned, and one module arranged between the swivel means and the nozzle head for a positioning lance (5) in which an extension channel (36) is arranged for each valve means and nozzle for the supply of fluid from the swivel means shaft (8) to the nozzle head.

Inventors: FILIPSSON MATS, FILIPSSON, MATS
Applicants: FILIPSSON MATS, VOLVO AB, AB VOLVO, FILIPSSON, MATS
Application year: 1996
Main classification: B05B12
IPC codes: B05B12, B05B15