2. Description of the Related Art Fluid-conveying pipes or tubes are used in many applications where it is desirable to transfer a fluid within a system or where the transfer of fluid is being used to convey force (as in brake or clutch applications) or thermal energy, as in refrigeration, air conditioning or heating applications etc. Within car engines for example, metal hydraulic pipes are used for the transfer of force, particularly in clutch systems and brake systems. Historically, pipes or tubes of this type were connected manually using screw threaded arrangements but more recently there has been a trend towards using snap- fit connectors that are more easily assembled, particularly in environments such as modern engine cavities where working space is at a premium.

Connectors are known in which a male connector, having a defined outer profile, connects with a co-operating female connector and connectors of this type are widely used to the extent that the automotive industry would expect any new connector to be compatible with existing profiles.

Furthermore, these known connectors provide a very satisfactory hydraulic seal at the connector/connector interface. However, a problem with known connectors of this type is that their interaction in terms of the connector/pipe interface is tess than ideal. Known connectors require a narrow flange to be formed at the end of a co-operating pipe, typically having a length of one point five millimetres on a six millimetre diameter pipe. This allows the end of the pipe to be crimped to the connector by applying compressive force to the

connector end.

Brief Summary of the Invention According to a first aspect of the present invention, there is provided a connector attached to a metal fluid carrying pipe, wherein said connector includes an axial bore having an internal cavity of extended diameter defined therein, wherein said pipe is attached to said connector by applying axial force to said pipe thereby forcing walls of said pipe to expand into said cavity; such that the end of said pipe extends into said connector by a length at least equal to the diameter to the pipe and further sealing is provided by the provision of an O-ring protecting an outer circumference of said pipe.

In a preferred embodiment, the metal carrying pipe is fabricated from mild steel. The pipe may terminate at a position within side the internal bore or, alternatively, the pipe may extend full distance of the internal bore within the connector.

According to a second aspect of the present invention, there is provided a connector attached to a metal fluid carrying pipe, wherein said connector includes an axial bore having an internal cavity for receiving said pipe, wherein a sealing O-ring contacts a circumference of said pipe; a first flange bracket is provided at the end of said pipe positioned within said cavity and a second flange is introduced to said pipe, wherein said O-ring is supported between said first flange and said second flange; and securing means secures said pipe beyond the position of the second position.

Brief Description of the Several Views of the Drawings Figure 1 shows a typical engine compartment of a motor vehicle having a hydraulic clutch system with male and female connectors; Figure 2 shows a cross-section of the male and female connectors identified in Figure 1;

Figures 3,4,5, and 6 detail procedures for applying a pipe to the male connector shown in Figure 2; Figure 7 shows a completed assembly, with a male connector attached to a pipe, fabricated in accordance with a procedure shown in Figures 3 to 6; Figure 8 details an engineering cross-section of the male terminated pipe shown in Figure 2 and Figure 9 details a similar mate terminated pipe as shown in Figure 8, modified slightly by having an extended connector; Figure 10 details a first alternative embodiment; Figure 11 details a second alternative embodiment; Figure 12 details a third alternative embodiment having a spring retaining latch and Figure 13 details the spring retaining latch identified in Figure 12 ; Figure 14 shows a fully assembled male and female connector of the type identified in Figure 1.

Detailed Description of the Invention The embodiments have been developed to provide improved assemblies for application as hydraulic parts in automotive clutch systems.

However, it must be emphasised that the embodiments and the embodied inventions may have application elsewhere in environments where fluid conveying pipes are required to be terminated.

A portion of an engine compartment of a motor vehicle is shown in Figure 1, having a clutch system 101. Hydraulic fluid is transported within the clutch system via metal pipes 102,103 and connections between pipes are made by attaching a male connector 104 to a first pipe with a co-operating female connector 105 being attached to a co-operating pipe.

Male connector 104 and female connector 105 are detailed in cross- section in Figure 2. The male connector 104 includes an O-ring 201 to provide a hydraulic seal between its outer profile 202 and the corresponding

inner profile 203 of the female connector 105. This interface is well known and tested within the automotive industry and embodiments disclosed herein, in terms of male connectors and female connectors, connect with known female and male connectors respectively, in addition to connecting with each other. Furthermore, connectors of this type may also be attached directly to engine components, or manufactured as an integral part of a component, allowing a suitably connected tube or pipe to be interface therewith.

The embodiment shown in Figure 2 represents a first preferred embodiment for attaching metal pipes (102,103) to both the male and female connectors (104,105). Unlike known connectors, configured to receive fluid- conveying pipes, the metal pipe is recevable within the connector such that the end of the pipe is displaced a significant distance d (equal to at least the pipe diameter) into the connector. Thus, as shown in Figure 2, the pipes are not merely held at their ends 204 but actually enter within the connector for a significant portion of the connector's length; that is for a significant distance d as required by the present invention.

The pipes are held in place by arrangements for securing a pipe to a connector, wherein these securing arrangements are displaced from the end of the connector, thereby providing a more secure mechanical and hydraulic interface between the pipes 102,103 and the connectors 104,105.

In the embodiment shown in Figure 2, each connector includes an internal cavity. Male connector 104 is configured with an internal cavity 205, with its co-operating female connector 105 having a similar internal cavity 206. Hydraulic sealing between the male connector 104 and its co-operating pipe 102 is established by the provision of an O-ring 207, with a similar O- ring 208 being provided within the female connector 105, to provide a hydraulic seal between a connector and its respective pipe.

During an assembly process, the internal cavities 205 and 206 facilitate radial expansion of a pipe so as to secure the pipe to its connector.

Thus, an assembly process is required so as to effect the radial expansion of

the pipe by mechanisms configured to apply an axial force. Procedures for applying pipe 102 to male connector 104 are illustrated in Figures 3,4,5 and 6.

In Figures 3,4 and 6, the male connector 103 is shown in exploded cross-section for illustrative purposes only and it should be appreciated that the male connector remains intact during the attachment process. Pipe 102 is secured by a clamp 301 so as to hold the pipe during the attachment operation. Male connector 104 has O-ring 207 inserted within an O-ring cavity 302. Thereafter, pipe 102 is inserted within the axial bore 303 of the connector through O-ring 207, as illustrated in Figure 3.

Axial force is applied to end 204 of pipe 102 by a punch 304 configured to traverse axially towards pipe 102, in the direction of arrow 305, for a predetermined distance, thereby applying an appropriate force to effect the required expansion of the pipe. Punch 303 is supported, in a spring loaded manner, within a punch holder 306. Punch holder 306 abuts against the connector 103 as the punch extends therethrough in a spring loaded fashion.

On application of the required force by punch 304, pipe 102 expands into cavity 205 as illustrated in Figure 4. In this way, the pipe 102 is mechanically secured within the connector 104, with hydraulic integrity being provided by O-ring 207. In addition to pipe 102 expanding into cavity 205, an overall radial expansion of pipe 102 occurs thereby increasing the overall interference of the outside surface of pipe 102 against the inside of bore 303.

The instant shown in exploded view in Figure 4 is also shown in cross-section in Figure 5. Force is applied by punch 304 which contacts against an end wall 401 of pipe 102. This causes an overall radial expansion of pipe 102 within bore 303 and, in particular, causes an expansion into cavity 205.

Thus, Figure 4 and Figure 5 show the maximum extent of travel for punch 304 after the punch has made contact with pipe 102 and has continued to extend, thereby applying force to pipe 102 and causing the

radial expansion into cavity 205.

At a distance displaced from the end of the pipe and at a distance displaced from the end of the connector, the pipe 102 expands into cavity 205 under the influence of force supplie by punch 304. Additional further expansion also occurs to provide a tight interference fit within bore 303.

As shown in Figure 4B, connector 104 is held firmly against punch 301 by means of compression spring 407, with the punch having travelled in the direction of arrow 305 so as to effect the radial expansion of pipe 102 into bore 303 and into cavity 205.

Thereafter, as shown in Figure 6, punch 304 retracts in the direction indicated by arrow 501, thereby leaving pipe 102 with a radially expanded portion 502 held tight by expansion cavity 205. The resulting assembly, showing male connector 104 attached to pipe 102 is shown in Figure 7.

An engineering cross-section of a terminated pipe 701, with a male connector 702, is shown in Figure 8. This shows that pipe 701 has undergone radial expansion at 703 so as to occupy the space of an internal cavity 704, thereby providing a secure mechanical attachment between the pipe 701 and the connector 702. Furthermore, hydraulic performance is enhanced by the provision of O-ring 705. This configuration avoids problems associated with creating a flange at the end of the pipe. Pipe 701 has been received within the connector 702 such that the end of the pipe is displaced by a significant distance d into the connector 702. Furthermore, cavity 704, displaced from end 706 of the connector, provides for securing the pipe 701 to the connector 702 by the creation of radially expanded portion 703.

The connector 702 is attached to mild steel pipe 701 after the pipe 701 has been inserted within an axial bore 707 of the connector. The pipe 701 is attached to the connector 702 by applying axial force to the pipe thereby forcing walls of the pipe to expand into the cavity 703. The end of the pipe extends into the connector by a length at least equal to the diameter of the pipe and further sealing is provided by the provision of O-ring 705

contacting an outer circumference of the pipe.

The embodiment shown in Figure 8 may be modified slightly as shown in Figure 9. In Figure 9 the connector body is extended at 710 so as to provide a greater degree of material between a rear end 711 of the connector and O-ring 705. However, such a modification does result in the connector body being made longer than its usually accepted size.

An alternative embodiment of the present invention is detailed in Figure 10. A similar procedure to that illustrated with respect to Figures 3,4, 5 and 6 is performed so as to provide expansion of a pipe 801 at expansion region 802 into an internal cavity 803. In this embodiment, a fluid conveying pipe 801 traverses the full length of the connector 804 such that, at the end of pipe 801 a flange 805 is created which then abuts against an O-ring 806.

Pipe 801 is secured in similar fashion to the securing clamp shown in Figure 4, whereafter a punch, similar to punch 304, is applied to the end of the pipe so as to force out flange 805. An advantage of the arrangement shown in Figure 10 is that the entire length 807 of the internal bore of the connector receives the fluid conveying pipe, which may be advantageous in some environments. However, it should be appreciated that the pipe would not extend through the entire distance of the female connector, although it would be displaced through the female connector by a significant distance, as required by the present invention.

A second alternative embodiment is detailed in Figure 11. In this example, a fluid-conveying pipe 901 has a trumpet-shaped flare 902 applied to its end, similar to the provision of a flange in known configurations.

However, the pipe 901 enters into a connector, such as male connector 903, by a significant distance and is secured at a position displaced from its end.

A second flange 905 is formed in the pipe at a position displaced from flanged end 902 of the pipe and an O-ring 906 is located between end flange 902 and displaced flange 905. End flange 902 abuts against an internal diameter 907 of the connector. Towards the end of the connector, the internal

diameter 907 is enlarged to provide a circular opening 908 configured to receive pipe 901. Thereafter, the ends 909 of the connector are crimped so as to mechanically secure pipe 901 within the connector 903.

The connector 903 is attached to mild steel pipe 901 by inserting the pipe into an axial bore 910. The bore includes an internal cavity 908 for receiving the pipe and the sealing O-ring 906 contacts the circumference of the pipe. The first flange bracket 907 is provided at the end of the pipe positioned within the cavity and a second flange 905 is introduced to the pipe. The O-ring 906 is supported between the first flange 902 and the second flange 905. The pipe is then secured by crimp 909 so as to secure the pipe beyond the position of the second flange.

A third alternative embodiment is illustrated in Figure 12. A fluid- conveying pipe 1001 is processed in a way substantially similar to the processing of pipe 901 shown in Figure 9. Thus, the pipe is provided with a flared end flange 1002, a displaced flange 1003 and an O-ring 1004 located between said fanges.

Male connector 1005 has a significantly larger opening 1006 at its receiving end, thereby providing a significant cavity 1007 behind flange 1003 after pipe 1001 has been located within the connector. During the fabrication process, a circular retaining latch 1008 is placed around pipe 1001 and after the pipe has been located within cavity 1006, force is applied axially, in a direction of arrow 1009, to the latch 1008 thereby forcing said latch into the space of cavity 1006 and mechanically securing pipe 1001 within the connector 1005.

Latch 1008 is shown in cross-section in Figure 13. The latch includes a plurality of fingers 1011 extending radially outwards beyond the end of the connector. Spaces of substantially similar revolution are included between each of these fingers, thereby allowing the fingers to deform radially, as indicated by arrow 1012, under the application of radially applied force.

Thus, in response to radial force being applied to fingers 1011, it is possible for the latch to be displaced axially in the direction of arrow 1013, thereby locating the latch within cavity 1006 of the connector. Thereafter, the radial force applied to fingers 1012 is removed, resulting in said fingers expanding elastically radially outwards, thereby firmly locating the latch within the cavity and thus securing the pipe 1001 within connector 1005.

An advantage of the third alternative embodiment, shown in Figures 12 and 13, is that it facilitates the manufacture of connectors using alternative materials, such as plastics, whereupon the latch 1008 may effectively snap-fit within its expansion cavity 1006.

Having attached a male connector to a pipe and having attached a female connector to a pipe, the connectors are assembled as shown in Figure 14. A male connector 1201 engages within a female connector 1202 and the connectors are then firmly held in place by means of a circlip 1203, arranged to enter receiving slots 1204 within the female connector 1202 so as to engage tightly against a slot machined within the male connector.

The improved arrangement for attaching pipes to connectors facilitates their rapid fabrication with fewer failures being produced. Furthermore, by facilitating a more secure attachment between pipes and their connectors, greater flexibility is achieved during the application of the systems within manufacturing processes, reducing production costs and increasing overall productivity.