FR2887473A1 - APPARATUS FOR DISASSEMBLING A PISTON, ITS USE AND INSTALLATION OF PROJECTION OF COATING PRODUCT COMPRISING SUCH AN APPARATUS - Google Patents

Abstract

This apparatus (100) comprises means (101, 106) for generating a difference between the pressures prevailing respectively in two volumes (V9, V'9) separated by a piston (91) inside a housing (L9 ) where slide (F1) this piston.The pressure difference makes it possible to move the piston (91) opposite the bottom (93) of the housing (L9) by suction effect (F2) or overpressure.

Description

The present invention relates to an apparatus for dismounting a piston

  placed in a cylindrical housing, its use, as well as a coating product projection installation comprising, between

others, such a device.

  In the field of the projection of coating product, it is known to use one or more piston tanks to supply product to project the projector or projectors. Depending on the pressure exerted by the piston of each reservoir on the product in it, the coating product is delivered to the projector (s) with controlled flow and pressure. It is known from EPA-0587467 to mount such a tank on the moving part of a multi-axis robot, close to a headlamp and to equip it with a cylindrical jacket inside which the piston of which the displacement is controlled to expel a coating product to a projector. Cleaning the bottom of the tank, that is to say of its area in which the ducts connected to the projector and the product sources, is delicate, because there may be gaps between the shirt and this bottom area, interstices in which the coating products tend to accumulate. However, it is often necessary to change the coating product, for example in the case of a projection installation of coating products on motor vehicle bodies. There is therefore a risk of pollution of a coating product by another.

  To solve this problem, one could consider using a blind folder disposed inside a tank. In this case, there is the problem of disassembly of the piston, such disassembly to intervene during maintenance operations. Indeed, the fact that the liner is blind prevents access to the front face of the piston, that is to say the side facing the bottom of the shirt, which prevents the operator to exert an effort to pressure on the piston to drive it out of the shirt.

  However, insofar as a piston is often mounted in a sealed manner, by means of joints or segments, inside the jacket, it is difficult to remove it by a simple pulling force, and all the more so. that there is no grip zone on the rear face of the piston.

  Similar problems arise in other areas where pistons are likely to be mounted within cylindrical housings in which they slide. This is particularly the case in dosing devices.

  Therefore, so far, blind shirts have not been used in systems with moving pistons.

  The invention solves these problems by providing an apparatus for disassembling a piston in place in a cylindrical housing, this apparatus for acting on the piston without access to its front face.

  The invention relates to an apparatus for disassembling a piston in place in a cylindrical housing, this piston separating said housing into two distinct volumes, one of which constitutes a volume of variable capacity for the storage of a product. This apparatus comprises means making it possible to generate a difference between the pressures respectively prevailing in these volumes such that the pressure in the storage volume of variable capacity is greater than the pressure prevailing in the other volume, whereas no product to be stored is in these volumes.

  Thanks to the invention, the pressure difference between the volumes induces a suction force on the piston, this suction force having the effect of moving the piston away from the bottom of the housing. The operator does not have to manually pull on the piston and will not damage it. The suction force is regularly distributed at the rear face of the piston, it can be exercised parallel to the axis of movement of the piston, which facilitates its removal. The apparatus is not limited to disassembling the pistons in place in a blind housing and can also be used to disassemble a piston installed in an open cylindrical jacket, as known from EP-A-0587467.

  According to a first embodiment of the invention, the apparatus comprises: - a body adapted to be sealingly attached to the aforementioned member or an element integral with this member, this body defining a volume opening suitable to be put into operation; communication with the aforementioned housing, and a suction device adapted to create a relative depression in the aforesaid volume when the body is attached to the aforementioned member or element.

  According to advantageous but non-compulsory aspects of the invention, such an apparatus may incorporate one or more of the following characteristics: the suction device is of the Venturi effect type, which is particularly simple to implement and takes into account the a source of compressed air is generally available near an installation comprising a piston mounted in a corresponding housing.

  - The body of the disassembly device is blind and the suction device is integrated in the bottom of this body. In the case where the suction device is of the Venturi effect type, the bottom of the body may comprise an air intake duct and an exhaust duct for this device.

  - The body is provided with an access opening to its interior volume, this opening being of dimensions at least equal to the transverse dimensions of the piston, which allows the piston reaches the end of the race within the body volume where it can then be retrieved by the operator.

  According to another advantageous embodiment of the invention, the apparatus comprises injection means, in the volume of variable capacity for storing the product, of a fluid other than the product to be stored under a pressure greater than atmospheric pressure.

  According to advantageous but non-obligatory aspects of the invention, such an apparatus may incorporate one or more of the following characteristics: the aforementioned means comprise a fluidic connection line with a source of fluid under pressure and, optionally, a discharge line.

  - The aforementioned means comprise a temporary element holding member, which defines the housing in the configuration of use of the piston, in a position where this element allows a displacement of the piston in a receiving zone located outside this housing.

  The invention also relates to the use of an apparatus as described above for removing a piston from a housing in which this piston slides.

  A particular use relates to the case where the housing in question is defined by a blind folder installed in a support body.

  Finally, the invention relates to a coating product projection installation which comprises at least one projector supplied with coating material from a piston tank, and at least one device as previously described used for disassembly of this material. piston when necessary.

  According to advantageous but not mandatory aspects, it can be provided that: The internal volume of the tank is defined by a blind member.

  - The tank is embedded on a moving part of a multi-axis robot, near the projector it feeds.

  The invention will be better understood and other advantages thereof will appear more clearly in the light of the following description of two embodiments of a disassembly apparatus according to the invention and its use in the context of the invention. a coating product projection installation according to the invention, given solely by way of example and with reference to the accompanying drawings in which: - Figure 1 is a schematic representation of a principle of a projection installation of coating product according to the invention and incorporating an apparatus according to the invention; FIG. 2 is a partial section of principle along line II in FIG. 1; - Figure 3 is a partial section of a part of the equipment visible in Figure 2, during a maintenance operation, these materials being equipped with a disassembly apparatus according to the invention; - Figure 4 is a partial section similar to Figure 3 showing the use of the apparatus with an alternative installation; and FIG. 5 is a section similar to FIG. 3 for an apparatus according to a second embodiment of the invention.

  In the installation I shown in FIG. 1, an automaton or robot 1 is placed near a conveyor 2 transporting objects to be coated, in this case parts of bodies 3 of motor vehicles. The robot 1 is of the multi-axis type and comprises a mobile frame 4 on a guide 5 extending parallel to the direction XX 'for conveying the bodies 3. An arm 6 is supported by the frame 4 and comprises several segments 6a, 6b , 6c articulated with respect to each other. The frame 4 is capable of rotational movements about a substantially vertical axis Z-Z '.

  The end segment 6c of the arm 6 supports a plate 7 on which is mounted, removably by means of a nut 71, an assembly 8 comprising a reservoir 9 of coating product and a projector 10 of rotary type and equipped with a rotating bowl 11.

  As envisaged in EP-A-0274322, connection means 12 and 13 are respectively provided on the plate 7 and on a fixed part 14 of the installation I to allow cleaning and periodic filling of the tank 8.

  As is more particularly apparent from Figure 2, the reservoir 9 defines a cylindrical housing L9 in which is disposed a piston 91 shown in an external view in the figures and slidable parallel to the direction of a central axis X9 of the housing L9. The housing L9 may be circular section or have another shape.

  The housing L9 is defined by a shirt 92 which is one-eyed and whose bottom 93 is noted. A duct 94 connects the housing L9 and the projector 10 which is shown in an external view in FIG. 2. The duct 94 makes it possible to supply the projector 10 with coating material when the piston 91 is moved towards the bottom 93, in the direction of arrow F1 in Figure 2.

  The liner 92 is received in a body 95 of the reservoir 9. Different unrepresented supply ducts of the projector 10 are formed in the body 95, as well as unrepresented supply ducts, cleaning product and coating product. of the volume V9 located between the front face 91a of the piston 91 and the bottom 93.

  The piston 91 is equipped with segments 98 making it possible to isolate the volume V9r from the volume V'9 situated in the housing L9 opposite the volume V9, that is to say between the rear face 91b of the piston 91 and the opening 092 of the shirt 92.

  An over-shirt 99 is mounted around the jacket 92 in the body 95 and limits the volume V'9 away from the bottom 93. The bottom 99a of this over-shirt is pierced with a passage opening 99b of the rod of a jack not shown for controlling the position of the piston 91 in the housing L9.

  When it is necessary to extract the piston 91 from the housing L9, the assembly 8 is removed from the plate 7 and the shirts 92 and 99 are extracted from the body 95. The over-shirt 99 is then removed, and a device 100 is mounted on the jacket 92 in the vicinity of its opening 092 by which the piston 91 can be placed in the housing L9. The apparatus 100 comprises a one-piece body 101 consisting of a bottom 102 and a skirt 103 defining an internal volume R1 which is in communication with the volume V'9 and the housing L9 when the apparatus 100 is mounted on the shirt 92. The skirt 102 is provided with an internal groove 104 in which is disposed an O-ring 105, which allows a tight fitting of the body 101 on the jacket 92.

  A suction device 106, of the Venturi effect type, is integrated in the bottom 102 and comprises an injection pipe 107 and an exhaust pipe 108, the downstream end 107a of the pipe 107 being provided with an internal narrowing 107b and disposed immediately upstream of the inlet zone 108a of the tubing 108. The end 107a is received in a housing 109 formed in the bottom 108 and in communication with the volume 101.

  The tubing 107 is connected to a source S of compressed air and the air flow, represented by the arrows E in FIG. 2, is controlled by a valve 110.

  The air flow E has the effect of creating, by the Venturi effect in the housing 109, a vacuum which propagates in the volume 101 and in the volume V'9, which has the effect of exerting on the piston 91 a suction force due to the difference of the pressures exerted respectively on the faces 91a and 91b, this force being represented by the arrows F2 and distributed on the face 91b of the piston 91.

  Thus, the fact of circulating air in the device 106 makes it possible to create a pressure difference AP between the pressure P9 prevailing in the volume V9 and the pressure P'9 prevailing in the volume V'9, this difference being positive , which represents the equation AP = P9-P'9> O.

  This pressure difference has the effect of progressively raising the piston 91 towards the opening 092, thanks to the effort F2.

  The internal dimensions of the skirt 103 are chosen slightly higher than those of the shirt 92. In other words, the opening Olof of the internal volume R a is wider, in the directions perpendicular to the axis X 9, than the shirt 92. and the piston 91, which allows the piston 91 can be moved to the inside of the volume Viol, so that a total withdrawal of the piston 91 relative to the housing L9 can be obtained.

  The only face of the piston likely to hit a fixed part during the withdrawal of the piston is its rear face 91b. In particular, the front face 91a of the piston, whose geometry must be precisely matched to that of the bottom 93 of the liner 92, is not likely to be damaged during the removal of the piston.

  In practice, the body 101 is mounted by hand on the liner 92, in the vicinity of its opening 092 and fixed in force thereon, the seal 105 sealing.

  According to a not shown variant of the invention, the body 101 could also be mounted, in a sealed manner, on the body 95.

  According to another variant, the device, the suction device could also operate with water.

  As shown diagrammatically in FIG. 1, the apparatus 100 can be kept in the immediate vicinity of the installation I during operation, for example in a housing 300 integral with a partition 14 defining the projection zone. The device is thus ready for use.

  As shown in FIG. 4, the apparatus of the invention can also be used with a reservoir 9 without a jacket and in which a body 95 defines a housing L9 in which a piston 91 can slide. In this case, the appliance 100 is mounted directly on an edge 95a of the body 95 defining an opening 095 for access to the housing L9. The apparatus 100 is of the same type as that described above, a positive pressure difference AP = P9-P'9 being used.

  The invention has been shown with an apparatus equipped with a suction device of the Venturi effect type. However, it is applicable to a suction device of another type, in particular an apparatus whose internal volume Vin is connected to an external vacuum source, for example of the vacuum pump type.

  An apparatus 200 according to the second embodiment of the invention is shown in FIG. 5 in use for a piston tank of the type shown in FIGS. 2 and 3. The jacket 92 of this tank is mounted, equipped its piston 91, in a central bore of a body 201 which comprises a bottom 202 and a skirt 203 surrounding this bore. In the bottom 202 is formed a conduit 207 connected by a feed line LA to a source S of pressurized water. In the bottom 202 is also formed a conduit 208 connected by a discharge line LE to a discharge tank B. The conduits 207 and 208 are respectively aligned with two orifices 931 and 932 formed in the bottom 93 of the folder 92 when the one it is in place in the body 201.

  As before, the piston 91 which slides inside the housing L9 constituted by the liner 92 sealingly separates a volume V9, defined between its front face 91a and the bottom 93, of a volume V'9 bordered by the face rear 91b of the piston and extending above it in the representation of Figure 5.

  When the skirt 92 is placed in the body 201, the over-shirt 99 is first removed then a ring 204 is disposed around the sleeve 92, bearing against an outer peripheral shoulder 92a of the ring 92 against which normally comes the over-cover 99. The over-shirt 99 is then put back in place around the liner 92 thus being offset from its configuration in which the reservoir 9 is used to store coating product. The offset of the over-shirt 99 is effective over a distance d equal to the height h204 of the ring 204 taken parallel to the axis X9.

  In practice, this height h204 is chosen greater than or equal to the height h91 of the piston 91, that is to say the distance between its front faces 91a and rear 91b. Preferably h204 is of the order of 1.2 times h91.

  With the conduit 207, it is possible to inject the volume V9 of water under a pressure of a few bars, which has the effect of increasing the pressure P9 in the volume V9 to a value greater than the pressure P'9 in the volume V'9, the pressure P'9 being substantially equal to the atmospheric pressure.

  The difference between the pressures P9 and P'9 which are exerted respectively on the front 91a and rear 91b of the piston 91 results in a force F2 distributed around the axis X9 and which has the effect of moving the piston 91 in the away from the bottom 93.

  The over-shirt 99 being displaced by the distance d as indicated above, a zone Z99 is created in the vicinity of its bottom 99a in which the piston can be received when it has traveled the entire height of the liner 92, this zone Z99 being located outside the housing L9. The piston 91 can then be easily recovered by removing the over-shirt 99.

  The fluid from the source S is not necessarily water. It may be another liquid or a gas, especially pressurized air.

  Although the invention finds particular use in the field of on-board tanks on multi-axis robots for the projection of coating products, it is applicable in all areas where a piston must be extracted from a shirt or a cylindrical body, in particular that of piston metering devices in general.

  The invention has been shown with a piston controlled by the rod of a jack. It is applicable with a pneumatically controlled piston.

  The invention is applicable regardless of the type of the projector 10 which may be electrostatic or non-rotating or pneumatic.

  The invention has been shown with a tank mounted on a movable part of an installation but also applies with a fixed tank possibly connected to a projector by a hose.

Claims (1)

13 Claims   1. Apparatus (100; 200) for disassembling a piston (91) in place in a cylindrical housing (L9), said piston separating said housing into two volumes (V9, V'9) one of which constitutes a volume ( V9) of variable storage capacity of a product, characterized in that said apparatus comprises means (101, 106; 201, 207) for generating a difference (AP) between the pressures (P9, P'9) prevailing respectively in said volumes such that the pressure (P9) prevailing in said storage volume (V9) with variable capacity is greater than the pressure (P'9) prevailing in the other volume (V'9), whereas no product at store is in these volumes.   2. Apparatus (100) according to claim 1, characterized in that it comprises: - a body (101) adapted to be reported sealingly on a member (92, 95) defining said housing or on a member (95). ) secured to said member, said body defining a volume opening (Viol) adapted to be placed in communication with said housing and - a suction device (106) adapted to create a relative depression in said volume, when said body is attached to said organ or element.   3. Apparatus according to claim 2, characterized in that said suction device (106) is of the Venturi effect type.   4. Apparatus according to one of claims 2 or 3,   characterized in that said body (101) is blind and in that said suction device (106) is integrated with the bottom (102) of said body.   5. Apparatus according to claims 3 and 4, characterized in that the bottom (102) of said body comprises an air intake duct (107) and an exhaust duct (108) for said suction device effect Venturi (106).   6. Apparatus according to one of claims 2 to 5, characterized in that said body (101) is provided with an opening (0101) for access to said volume (Viol) of transverse dimensions at least equal to the transverse dimensions of said piston (91).   7. Apparatus according to claim 1, characterized in that it comprises means (201-207, LA, S, 208, LE, B) for injection into said volume of variable capacity (V9) of a fluid, other the product to be stored under a pressure (P9) greater than the atmospheric pressure.   8. Apparatus according to claim 7, characterized in that said means comprise a line (207, LA) for fluid connection to a source (S) of pressurized fluid and, optionally, a discharge line (208, LE).   9. Apparatus according to one of claims 7 or 8, characterized in that said means (201) comprise a member (204) for temporarily holding an element (99), which delimits said housing (L9) in configuration of use of said piston (91), in a position (Figure 5) wherein said element allows movement of said piston in a receiving zone (Z99) located outside said housing.   10. Use of an apparatus (100; 200) according to one of the preceding claims for the withdrawal of a piston (91) of a housing (L9) in which slides (F1) said piston.   11. Use according to claim 10 wherein said housing (L9) is defined by a blind sleeve (92) installed in a support body (95).   12. Installation (I) for projecting coating product comprising at least one projector (10) supplied with coating material from a reservoir (9) piston (91), characterized in that it comprises at least one Apparatus (100; 200) according to one of claims 1 to 9 for disassembling said piston.   13. Installation according to claim 12, characterized in that the internal volume (L9) of said reservoir 5 (9) is defined by a blind member (92).   14. Installation according to one of claims 12 or 13, characterized in that said tank (9) is embedded on a movable part (6c) of a multi-axis robot (6), near said projector (10).