FR2552852A1 - CONNECTION DEVICE FOR PLASTIC TUBES - Google Patents

Abstract

Connector for plastic tubes conveying a compressed fluid, wherein the tube is instantaneously mounted by simply pushing means which make the tube undisconnectable. The female means of the instantaneous connector (1, 9) comprises a cylindrical guiding male part (1k, 9k), and the tubular male member (9) of semi-flexible plastic material comprises a circular recess (3h) of which the cylindrical surface is conformed with a small tolerance to the cylindrical guiding male part (1k), thereby forming a metal guiding support absorbing the lateral stress which might be exerted on the tubular male member. The invention is used for the connection of compressed air brake circuits.

Description

Connection device for plastic tubes
The present invention relates to a connection device for plastic tubes comprising instant connection means.

 This type of connection includes means which make it possible to mount a tube or a connection accessory in an instantaneous connection by a simple push on the tube or the accessory without any other operation and so that the tube is held in the connection. and that sealing is ensured. These instant fittings are well known and they have been the subject of French patents 2,012,796, 2,3I9,833, 2,258 ~ 585 and 2,749,406 which belong to the applicant. These fittings are widely used in industry for the connection of plastic pipes on machines operating with compressed air.

 Furthermore, the braking of the trucks is carried out by means actuated by compressed air and currently all the old circuits in steel tube are replaced by circuits in plastic tube of the polyamide type with high characteristics.

 Because lton uses these plastic tubes which save weight, it has become necessary to save time when mounting the very many connections of the braking system which is complex. In addition, it must be taken into account that braking safety is paramount on trucks and that a braking failure presents a great danger on these vehicles. It is for these reasons that high security instant fittings have been specially developed for the braking system of trucks and the present invention relates to this type of fittings.

 Push-in fittings of the known type do not meet the conditions required for their use in truck braking systems, since they imperceptibly scratch the perfectly smooth plastic tube and cause extremely small leaks, but unacceptable for this type of use.

 The instant disassembly of a special braking circuit, excessively increasing the price of the connection device, the following technique is adopted by the manufacturers of motor vehicles.

 1) Instant mounting of the tubes and connecting members on the assembly line.

 2) Disassembly impossible or requiring unscrewing of the fitting itself from the device; the tubes and accessories remaining non-removable on the plastic tubes.

 The present invention relates to a connection device for plastic tubes conveying a compressed fluid and in which the tube is instantly mounted by a simple push in means making the tube non-removable.

 The connection device consists of connection accessories provided with at least one female instantaneous connection means and at least one tubular male member, said accessories being combined with mounting members on an apparatus comprising a female connection means instantaneous.

 In accordance with the present invention, the female instantaneous connection means comprises a male part, of cylindrical guide, and the tubular male member of semi-flexible plastic material comprises a circular recess, the cylindrical surface of which follows the male guide part with little play. cylindrical thus constituting a metal support guide absorbing the lateral forces likely to be exerted on the tubular male member.

 The device according to the invention makes it possible to obtain a connection having total security of the resistance of the tubular male member due to the metallic guide support and the absorption of lateral forces on the tubular male member which make it possible to obtain a reliable product that does not risk breaking.

 This cylindrical guide arrangement on the tubular male members and on the female instant connection means can be applied both to the device mounting members or cartridges and to the connection accessories, so that it is very easy to mount a connection accessory on another accessory by fitting a male member into a female member with a support guide according to the invention.

 In order to obtain this metallic support of the tubular male organ made of plastic, it is provided that the fitting depths of the tubular male organ have a length exactly adapted to the depth of the cartridge and to the instant female connectors of the various accessories. . From this mantle, a tube or an accessory with a tubular male member can be mounted, the depth being the same in the instant female connector.

 It follows that the tube and the tubular male member are fitted and maintained over the entire axial length of the cartridge and that the instantaneous connection means either of the cartridge or of the accessories are housed and limited by flat-bottom housings. which corresponds to an important characteristic of the invention.

 In fact, unlike French patent no. 2.3I9.833, which reserves significant guidance of the tube in the device on which the device is installed, requiring special housing and a significant depth, the device according to the invention includes guidance of the tube and the male organ in the cartridge or the accessory allowing the use of short housings, easy to house, flat bottom, simple to carry out in all the apparatuses and using standardized tapped housings or smooth housings.

 your cartridge formed a short and compact, simple assembly which can be screwed, crimped or fitted, the tube or tubular male member of which does not protrude from the clamp constituting one of the members of the instant connection means.

The invention, more particularly intended for the braking device by compressed air, is not limited to this use and can also be suitable for all medium-pressure fluid circuits which is limited by the resistance of the plastic tubes.
Other characteristics and advantages of the invention will be better understood on reading the following description of several embodiments and with reference to the appended drawings in which:
Figure 1 is an elevational view in axial section of an embodiment of the connection device according to the invention.

 Figure 2 is the same view as in Figure 1, the cartridge being separated from the accessory.

 Figure 3 is an axial sectional view of a cartridge mounted on an apparatus.

 Figure 4 is an axial sectional view of a cartridge in the disassembled state.

 Figure 5 is an axial sectional view of a cartridge in which is mounted a tube provided with a fur.

 Figure 6 is an elevational view in axial section of another embodiment of a connection device.

 Figure 7 is an axial sectional view of a cartridge with another cylindrical guide mode.

 Figure 8 is an elevational view in axial section of an assembly of several connection accessories.

 Figure 9 is an elevational view in axial section of an accessory having a male member.

consisting of a plastic tube element.

 Figure 10 is an elevational view in axial section of the accessory of Figure 9 mounted in a cartridge.

 Figure 11 is an elevational view in axial section of the connection device in which the sleeve is crimped into the body of the accessory.

 Figure 12 is an axial sectional view of a connection device in which the cartridge is crimped on the device.

 FIG. 13 is a view in axial section of the cartridge shown in FIG. 12.

 Figure 14 is a sectional view of a connection device in which the instant connection clamps are cut sheet metal.

 Figures 15 to 17 are views in axial section of cartridges having cut sheet metal clamps.

 Figures 18 to 21 are exterior elevation views of several embodiments of accessories.

In Figures 1, 2, 3 and 4 there is shown an embodiment of a connection device according to the invention which is mounted on a device 2 having a tapped hole 2a of shallow depth, delimited by a flat bottom 2b and in which is screwed a cartridge 1 by its threaded part If with interposition of an O-ring seal lc
The cartridge 1 has internally a cylindrical bore lm (FIG. 3) in which is provided a groove receiving an O-ring seal lb, said bore being extended by a double conical part ln, and a bore lo in which is housed a clamp deformable split 6 comprising one or more hooking teeth 6a and a washer maintained by a crimped edge 1-Z of the cartridge, limiting and retaining the clamp 6 which has an unsplit part 6b of the same diameter as the bore 1 m .

 On the cartridge 1 is mounted an accessory in the form of a connection square 3 comprising a tubular male member 4 of semi-flexible plastic material engaged in the cartridge 1 (Fig.l).

 The tubular male member 4 is mounted in the body 3f of the accessory by means of its flange 4a which is retained by a metallic piece 3b in the form of a cup engaged in a circular housing of the body 3f and locked in the latter by means a crimped edge 3c, a seal 3a being disposed between the collar 4a of the male member and the housing of the body 3f receiving said collar.

 The tubular member 4 has a bore 4b, which opens into an inner conduit 3n of the body 3f of the accessory, said conduit 3n opening itself at its other end into a socket 9 which has a threaded part 9b screwed into a hole tapped 3d, flat bottom 3e, with interposition of an O-ring seal 9a.

 The socket 9 has internally the same shape as the cartridge 1 and receives like this a seal 1b and a clamp 6. In the socket 9 is mounted the end of a tube 5 made of semi-flexible plastic which is hung by the tooth 6a of the pliers 6.

 Furthermore, the square accessory 3 is held by its tubular male member 4 which is engaged and hooked in the clamp 6 housed in the cartridge 1, said accessory thus being permanently secured and cannot be dismantled with the cartridge 1 and the tube 5 .

 The accessory 3 can be oriented along 3600 around the axis of the cartridge 1.

 The disassembly of the connection means can only be carried out by unscrewing the cartridge (the assembly being rotary) from the body 2 by its flange lh which has the external shape of a hexagon.

 The tubular member 4 being of semi-flexible plastic material to allow it to hang on to the clamp 6, it therefore has limited resistance and could not in the long term withstand significant lateral forces which would be produced by pulls or other untimely efforts exerted on the tube 5.

 The main characteristic of the invention therefore resides in the fact of providing a resistant metallic support means absorbing lateral forces.

 This result is obtained by providing on the cartridge 1 in the flange lh a circular recess lg delimiting a male cylindrical guide part lk which is in contact with the cylindrical surface 3h of the cup 3b surrounding the tubular male member 4 at its base.

 In this way the cylindrical surface 3h matches the male guide part lk with little play.

 The circular recess lg, on the cartridge 1 saves the maximum space (Fig.3) so as to obtain a cartridge 1 very slightly protruding from the device 2 and an angled accessory 3 having the smallest possible height.

 It follows that the cartridge 1 can be arranged in a tapped hole 2a of standard or short depth, limited by a flat bottom, that the socket 9 is also in a shallow tapped hole 3d limited by a bottom 3e and that the tube 5 and the male member 4 are engaged at the same depth "t" providing a standard depth dimension for the same nominal diameter.

 The diameter of the tube 5 is exactly equal to the diameter of the male member 4 and they are capable of being engaged in the same instant connection means.

 The tube 5 or the male member 4 do not exceed the cartridge 1 or the sleeve 9 and occupy the entire length "z". In the cartridge 1, it is possible to mount either directly a tube 5, or a male member 4, so that it is possible to mount in the said cartridge any accessory of any shape.

 For this purpose the diameters of the parts 3h, lk, and 9k, are identical to the mounting tolerances and constitute guide means.

 In Figure 5 there is shown a cartridge 1 mounted on an apparatus 2 and in which is engaged the end of a tube 5 whose central part is supported against creep by a fur 7 consisting of a metal tube very sheet slim. The fur 7 makes it possible to considerably improve the heat resistance and in the long term, by eliminating the creep of the plastic tube 5 at the level of the tooth 6a, the pliers and the tightening of the joint 1b; it is essential for the truck braking system activated by compressed air.

 The useful depth of the cartridge is equal to Itzll, that is to say almost all of its length.

 Figures 6 and 7 show an alternative embodiment of Figure 1 in which the circular recess 1gaza has been removed and in which the male cylindrical guide part lk protrudes completely above the flange lh.

 Furthermore, the tubular male member 4 is held by a simple washer 8 by an edge of the body 3f of the accessory 3. The metallic cylindrical guide surface 3h is produced by the body 3f which is itself made of metal. The sleeve 9 is elongated to have the same depth as the cartridge 1 which in this case is a little longer than in the previous example and it protrudes a little more from the device 2 (Fig. 6). In this case, the q 9 socket 9 and the cartridge 1 have a length 11 greater than the length "1" of the previous embodiment.

 In FIG. 8, Qn represents an assembly of an accessory 3 bis identical to the accessory 3 and which comprises a tubular male member 4 of plastic material which is engaged in the socket 9 of the accessory 3.

 The assembly can be carried out because the depths "Z" are identical and the diameter of the male member 4 is the same as that of the socket 9.

 Therefore any male-female accessory can receive any accessory of the same diameter with the guide means 9k.

In FIGS. 9 and 10, a variant of FIG. 2 is shown in which the tubular male member 4 in one piece made of molded plastic material has been replaced by an element Sa cut from a tube 5 and on which a ring 10 with thin lips is crimped. . The tube element
Sa is supported over its entire inner diameter by a thin metallic fur 7a. The tube element Sa and its fur 10 are mounted as in FIG. 2.

 The advantage lies in the fact that for the male member Sa, the same tube 5 as for the pipes.

 In FIG. 11 a variant of FIG. 1 is shown in which the sleeve 9 is not screwed onto the body 3f of the accessory as before, - but it is simply fitted into a cylindrical housing 3m and held by an edge crimped 3i formed on the body 3f. The disassembly of the connection device being carried out by unscrewing the cartridge 1 from the device 2.

 Figure 12 shows an alternative embodiment of Figure 11 in which not only the sleeve 9 is fixed by crimping but also the cartridge 1 which is screwed in the previous embodiments.

 For this purpose, the cartridge 1 is engaged in a cylindrical housing 2m and it is retained by a crimped edge 2p formed on the device.

 The device is no longer removable or repairable and the cartridge is smaller due to the fact that the collar delimited by a hexagon is removed.

 The crimp cartridge 1 shown alone in FIG. 13 does not have a hexagon, but a groove lp intended for crimping and its seal lc, is arranged in another groove.

 The crimp cartridge is almost identical to the socket 9, but it additionally includes the washer 1c, which maintains the clamp and is used as a stop for the tube.

 In FIG. 14, a variant of FIG. 1 is shown in which the pliers made of turned and milled or molded metal are replaced by a holding piece or pliers made of cut sheet metal 11, comprising elastic hooking lugs lla, lugs of fixing llb, and stop tabs llc, said clamp 11 being held in the cartridge 1 by a crimped edge 12 which allows it to rotate along the axis of the cartridge. The latching tabs lla have the characteristic of allowing the tube to be hooked in a non-removable manner. The same clamp 11 is mounted in the cartridge 1 and the socket 9 which, as before, have the guide means lk, 3h, 9k.

 FIG. 15 shows the cartridge alone provided with a clip 11 made of cut sheet metal with its latching lugs lla, its holding lugs Ilb, and its stop lugs for the tube 5.

 FIG. 16 shows a variant of the clamp 11 which is produced in two parts, the holding part 12 with the latching lugs 12a and the washer 1a already used in FIGS. 1 and 16.

 In FIG. 17, a variant of FIG. 16 is shown, in which the washer 1c has been deleted and the sheet metal clamp 13 for holding is placed in a groove ls, of the cartridge, said clamp 13 comprising lugs 13c of tube stop. The clamp 13 is mounted by elasticity because it is made of rolled sheet metal with a slot.

 In Figures 18 to 21, there are shown non-limiting examples of mounting accessories, each of which must include at least one instantaneous female connection inlet and at least one tubular male member made of semi-flexible plastic.

 In the case of FIG. 18, which represents a straight accessory 14 with a female part 14a and a male part 14b, we are in the presence of a male-female union connection if the diameters 14a, 14b are equal, of a reduction if the diameter 14a is smaller than 14b, and a magnification accessory if the diameter 14a, is larger than 14b.

 In Figure 20, there is shown a T-shaped accessory 15 whose straight parts 15a are female and comprising a male member 15b. The diameters of the three ends can be equal, two can be equal, or all three can be unequal.

 In Figure 21, there is shown a tee fitting 16, the male and female ends of which are arranged differently.

 The method which would consist in reversing the metallic support guide means, in which the cylindrical male part k is located on the tubular plastic male part and the female part 3h, on the female instant connection means, also remains in the field of the invention.

 The present invention finds particular application in the ultra-fast assemblies of compressed air circuits for truck braking, but it can also be used in all industries to economically establish fluid circuits for pressures ranging from vacuum to 20 bars, with quality plastic pipes.

 Of course, the invention is not limiting and those skilled in the art may make modifications to it without departing from the scope of the invention.

Claims (16)

R E V E N D I C A T I 0 N S 1. Connection device for plastic tubes conveying a compressed fluid in which the tube is instantly mounted by a simple push in means making the tube non-removable, said device consisting of connection accessories provided with at least one female means instant connection and at least one tubular male member, said accessories being combined with mounting members on an apparatus and comprising a female instant connection means, characterized in that the female instant connection means (1, 9) comprises a male cylindrical guide part lk, 9k, and in that the tubular male member (4) made of semi-flexible plastic material has a circular recess 3h, the cylindrical surface of which conforms with slight play, the male cylindrical guide part lk thus constituting a metallic support guide absorb the lateral forces liable to be exerted on the tubular male member. 2. Connection device according to claim 1, characterized in that the mounting of the accessories on a device (2) is carried out by means of a cartridge (1) screwed into a tapped hole (2a) of the device with interposition of 'a seal (lc), said cartridge containing a female instantaneous connection member occupying the entire length Z of the latter, said connection member comprising an elastic split clamp (6) provided with at least one row of teeth d 'hooking (6a), an O-ring (lb) and a crimped washer (le), holding the clamp and tube stop, said cartridge having a male cylindrical guide part (lk) formed from a housing annular (lg) in a flange (lh) of the cartridge delimited externally by a hexagon. 3. Connection device according to claims 1 and 2 characterized in that the mounting and connection accessories comprise a tubular male member (4) protruding from the body of the accessory with a length I identical to the interior depth of a cartridge (1) or a socket (9) mounted on the accessory, and containing an instantaneous connection member. 4. Connection device according to claim 1, characterized in that the tubular male member (4) is fixed in a body (3f) of the accessory by means of a stamped cup (3b) which is crimped in the body (3f) by delimiting an annular recess (3g) having a cylindrical guide surface (3h) of identical diameter, increased by a very small clearance, to that of the male cylindrical guide part (lk, 9k). 5. Connection device according to claim 1 characterized in that the tubular male members (4) are of semi-flexible plastic material of hardness substantially equal to that of the tube connections (5). 6. Connection device according to claim 1, characterized in that the tubular male member consists of a plastic tube element (5) internally reinforced by a metallic fur (7a) consisting of a thin sheet, said plastic tube element being provided at one end with an annular retaining piece (10) crimped on said element. 7. Connection device according to claims 1 and 3, characterized in that on the body (3f) is mounted by a screwed part with the interposition of a seal (9a), a socket (9) having a depth " Z "identical to that of the cartridge (1), said sleeve containing a seal (lb) and a clamp (6) identical to those of the cartridge (1), said sleeve (9) having a flat bottom against which is likely to come into abutment the clamp (6) and the tube (5), said bushing (9) having a cylindrical male guide means (9k) allowing the guiding of the tubular male members (4), said guide (9k) having the same diameter as the cylindrical male part (lk) of the cartridge. 8. Connection device according to claim 1, characterized in that the accessories are capable of being mounted on each other in a complementary manner and comprise male and female end pieces so as to obtain in particular a bend, a male female union connector , a tee, a cross. 9. Connection device according to claims 1 and 2, characterized in that the cylindrical male guide part (lk) consists of a cylindrical extension extending beyond the flange (lh) delimited by a hexagon such that the cartridge has a length f't "greater than the length" Z ". 10. Connection device according to claim 1, characterized in that the tubular plastic male member (4) is held in the body (3f) of the accessory by a washer (8) crimped in said body and in which the annular recess (3g) is made in the body of the metal fitting to form the guide surface (3h). 11. Connection device according to claims 1 and 2, characterized in that the threaded hole (2a) into which the cartridge (1) is screwed onto the device (2) has a relatively short length and a flat bottom (2b) so that it is completely filled by the cartridge (1) and that the tube (5) does not protrude into the body (2) of the device. 12. Connection device according to the rer vendication 1, characterized in that each instant connection means mounted in a member comprising a male cylindrical guide part (il), (9k), is capable of receiving selectively the end of a tube (5) or a tubular male member (4) at the same depth "I". 13. Connection device according to claims 1, 2 and 7, characterized in that the assembly of a tube (5) or a tubular male member (4) in an instantaneous connection means is non-removable, the tube becoming integral with the cartridge (1) or the fitting (3), the separation of the device from the piping being capable of being carried out by unscrewing the cartridge (1) from the device (2). 14. Connection device according to claims 1 and 7, characterized in that the sleeve (9) is mounted on the body (3f) of the accessory in a smooth housing (3m) with a flat bottom and held by a crimped edge ( 3i) of the body (3f), said bushing having a male cylindrical guide part (9k), and a length "zon. 15. Connection device according to claim 1, characterized in that the cartridge (1) is mounted on the device (2) in a cylindrical housing (2m) with a flat bottom of shallow depth and maintained by a # flange (2p) crimped into a groove (lp) of the cartridge. 16. Connection device according to claim 1, characterized in that the attachment clip of the instant connection means consists of a piece of cut sheet metal (11, 12, 13) comprising multiple attachment tabs (IIa, 12a, 13a) self-catching, said clamp being fixed in the cartridge (1) or the sleeve (9) by direct crimping, crimped washer, screwing of the sleeve or groove in the cartridge.