Patent Description:
A hose connector formed at the end of a metal tube is typically used to connect the tubing to a flexible polymeric hose, such as, fuel tubing used between a vehicle's fuel tank and an engines carburetor or other fuel metering system. The fuel tubing can be part of a long rigid fluid line or a stem defined at the end of a connector body. The polymeric hose is fitted on the outer periphery of the hose connector to form a fluid connection between the fluid line or connector body with the polymeric hose. For this type of hose connector, a fluid tight seal is maintained only by the tightness of the polymeric hose. Therefore, when creep deformation of the hose occurs due to heat deterioration, the holding force decreases such that a fluid tight seal cannot be maintained. Other factors which contribute to a lack of fluid tight seal include variations in the size and tolerances of the hose connector and the polymeric hose, the inner surface finish of the hose, the outer surface finish of the metal tubing, the effects of chemicals, and the hardness and swell of the hose. <CIT> discloses a connection structure between thin diameter metal tube and flexible hose. <CIT>) provides a connection structure for a resin pipe to a metal pipe, for preventing leaks. <CIT>) discloses a connection structure of a flexible tube fitted to the end portion of a metal pipe.

The present invention is defined in the accompanying independent claims, with optional and preferred features defined in the accompanying dependent claims. This disclosure relates to a hose connector formed at the end of a rigid pipe body or tubing and used to connect the pipe body to a flexible polymeric hose.

In a first embodiment, a hose connector structure is provided comprising a rigid pipe body having a frustoconical front end extending outward from a tip end to a radially enlarged first ring portion. The first ring portion has an annular face extending at a consistent diameter from the frustoconical front end and terminates at a circumferential first step with the first step comprises tapering walls extending from a rear edge of the first ring portion annular face and decreasing in diameter to a first step rear edge. A radially reduced second ring portion extends from the first step rear edge backwards at a constant diameter to a circumferential rear edge. A circumferential second step extends from the second ring portion circumferential rear edge and comprises walls that taper from said circumferential rear edge in a decreasing circumferential diameter to a mid-section of the pipe body. A flexible hose is adapted to be inserted by pressure over the pipe body at the tip end until it passes beyond the second step to the mid-section of the pipe body.

In a second embodiment, a hose connecter structure is provided comprising a rigid pipe body having a frustoconical front end extending outward from a tip end to a radially enlarged first ring portion. The first ring portion has an annular face extending at a consistent diameter from the frustoconical front end. A radial second ring portion has walls that extend parallel to the first ring portion annular face and having an external annular diameter that is less than the annular diameter of the first ring portion, said second ring portion being spaced from the first ring portion. An annular groove is formed between the first ring portion annular face and the second ring portion annular face. The second ring portion annular face terminates in a circumferential first step of a decreasing diameter from a rear edge of the second ring portion annular face to a mid-section of the pipe body. A flexible hose is adapted to be inserted by pressure over the pipe body at the tip end until it passes beyond the second ring portion and first step to the mid-section of the pipe body.

The figures, discussed below, and the various embodiments used to describe the principles of the present invention in this patent document are by way of illustration only and should not be construed in any way to limit the scope of the invention. Those skilled in the art will understand that the principles of the invention may be implemented in any type of suitably arranged device or system.

A hose connector of the disclosure is formed at the end of a rigid pipe body or tubing typically used to connect the pipe body to a flexible polymeric hose, such as the tubing used between a vehicle's fuel tank and engine carburetor or other fuel metering system. The pipe body can be part of a long rigid fluid line or a stem defined at the end of a connector body. The polymeric hose is fitted on the outer periphery of the hose connector to form a fluid connection between the fluid line or connector body with the polymeric hose.

<FIG> shows a first embodiment in which a rigid pipe body <NUM> extends horizontally from a rear end <NUM> to an opening <NUM> at a frustoconical front end <NUM>. The frustoconical front end <NUM> extends outward from a tip <NUM> to a radially enlarged first ring portion <NUM>. The first ring portion <NUM> includes an annular face <NUM> that extends backwards at a constant diameter from the frustoconical front end <NUM> towards the pipe body rear end <NUM>, terminating at a circumferential first step <NUM>. The first step <NUM> includes tapering walls <NUM> that extend backward toward the pipe body <NUM> rear end <NUM> in a decreasing diameter and terminating at a rear edge <NUM>.

A second ring portion <NUM> has walls <NUM> that extend at a constant diameter backward from edge <NUM> to a rear edge <NUM>. Second ring portion <NUM> has an external annular diameter that is less than the external annular diameter of first ring portion <NUM>. Walls <NUM> of second ring portion <NUM> extend backward for a distance that is at least twice the distance that face <NUM> of first ring portion <NUM> extends backwards. That is, the surface width of walls <NUM> are at least twice the width of face <NUM>. The circumferential second step <NUM> has walls <NUM> that taper backwards from the circumferential rear edge <NUM> of the cylindrical portion <NUM> in a decreasing diameter for a distance equal to the distance of walls <NUM> of first step <NUM>. The second step <NUM> terminates at a mid-section <NUM> of rigid pipe body <NUM>.

A radially enlarged barrel portion <NUM> is formed on the rear end <NUM> of the rigid pipe body <NUM>, opposite and spaced away from the frustoconical front end <NUM>. An outer surface of barrel portion <NUM> on the side nearest to the midsection <NUM> of pipe body <NUM> has a first tapered surface <NUM> of which the diameter becomes smaller as the distance to the midsection <NUM> decreases. An outer surface of the barrel portion <NUM> that is on the opposite side to the first tapered surface <NUM> is a second tapered surface <NUM> that is inclined in the opposite direction of the second tapered surface <NUM>. The inclination angles of the first and second tapered surfaces <NUM>, <NUM> are substantially the same. The barrel portion <NUM> extends parallel to the first ring portion <NUM> and has an external annular diameter that is equal to the external annular diameter of the first ring portion.

As can be best seen at <FIG>, a flexible tube <NUM> made of polyamide resin, fluoroplastics, olefin resin, and so on, has an inside diameter that is slightly less than the outside diameter of pipe body <NUM>. Therefore, when the flexible tube <NUM> is press-fitted onto pipe body <NUM>, the flexible tube <NUM> makes a tight liquid-proof contact with pipe body <NUM>. That is, with tube <NUM> installed, its inner surface <NUM> forms a tight hermetic closure with the first ring portion <NUM>, walls <NUM> of second ring portion <NUM>, the mid-section <NUM> of the pipe body <NUM> and tapered surfaces <NUM>, <NUM> of barrel portion <NUM>. The flexible tube <NUM> can be installed to at least the mid-section <NUM> of pipe body <NUM>, however, it is fully installed when tip portion <NUM> reaches to the rear end <NUM> of pipe body <NUM>.

<FIG> illustrates a second embodiment of the present disclosure. In the second embodiment, a rigid pipe body <NUM> horizontally extends from a rear end <NUM> to an opening <NUM> at a frustoconical front end <NUM>. The frustoconical front end <NUM> extends outward from a tip <NUM> to first radial ring <NUM>. A second radial ring <NUM> is formed on the base side, (i.e., a portion opposite to the tip <NUM>) of the frustoconical front end <NUM>. The second ring portion <NUM> has walls <NUM> that extend parallel to the first ring portion14 forming a spool that defines an annular groove <NUM> therebetween. The second ring portion <NUM> has an external annular diameter that is slightly less than the annular diameter of the first ring portion <NUM>. The second ring portion <NUM> ends at a circumferential first step <NUM>. The first step <NUM> includes tapering walls <NUM> that extend backward toward the pipe body rear end <NUM> at a decreasing diameter terminating at a rear edge <NUM> at a mid-section <NUM> of rigid pipe body <NUM>.

A radially enlarged barrel portion <NUM> is formed on the rear end <NUM> of the rigid pipe body <NUM> opposite and spaced away from the frustoconical from end <NUM>. An outer surface of barrel portion <NUM> on the side nearest to the midsection <NUM> of pipe body <NUM> has a first tapered surface <NUM> of which the diameter becomes smaller as the distance to the midsection <NUM> decreases. An outer surface of the barrel portion <NUM> that is on the opposite side to the first tapered surface <NUM> is a second tapered surface <NUM> that is inclined in the opposite direction of the second tapered surface <NUM>. The inclination angles of the first and second tapered surfaces <NUM>, <NUM> are substantially the same. The barrel portion <NUM> extends parallel to first ring portion <NUM> and has an external annular diameter that is equal to the external annular diameter of the first ring portion.

As can be best seen at <FIG>, a flexible tube <NUM> made of polyamide resin, fluoroplastics, olefin resin, and so on, has an inside diameter that is slightly less than the outside diameter of pipe body <NUM>. Therefore, when the flexible tube <NUM> is press-fitted onto pipe body <NUM>, the flexible tube <NUM> makes a tight liquid-proof contact with the pipe body <NUM>. That is, with tube <NUM> installed, its inner surface <NUM> forms a tight hermetic closure with the first ring portion <NUM>, the second ring portion <NUM>, the mid-section <NUM> of the pipe body <NUM> and tapered surfaces <NUM>, <NUM> of barrel portion <NUM>. The inner surface <NUM> of flexible tube <NUM> depresses inward into annular groove <NUM> to bridge between the first ring portion <NUM> and the second ring portion <NUM> forming a concaved bridge surface <NUM> therebetween. The concave bridge <NUM> serves to not only provide a tight seal between the first and second ring portions <NUM> and <NUM> but also a more robust grip on the hose connector structure due to the difficulty of the concave bridge surface <NUM> overcoming the height of the rings. The flexible tube <NUM> can be installed to at least the mid-section <NUM> of pipe body <NUM>, however, it is fully installed when tip portion <NUM> reaches to the rear end <NUM> of pipe body <NUM>.

As is shown in <FIG>, the annular groove <NUM> can also have an O-ring <NUM> installed therein. The O-ring <NUM> may be made of fluorocarbon polymers, or other fluoropolymers. With the O-ring <NUM> installed in groove <NUM>, flexible tube <NUM> inner surface <NUM> forms itself over O-ring <NUM> to make a convex sealing portion <NUM>. Sealing portion <NUM> thus makes a tight hermetic seal with O-ring <NUM> when the tube <NUM> is installed over pipe body <NUM>.

The frustoconical front end <NUM> and first ring portion <NUM>, first step <NUM> and second ring portion <NUM> and its second step <NUM> may be formed on pipe body <NUM> using any technique that forms stepped-barrel structures on rigid pipe bodies. Additionally, the barrel portion <NUM> may also be formed on pipe body <NUM> using a tapered-barrel technique. The second ring portion <NUM> and first step <NUM>, of the second embodiment of <FIG>, may be formed using any spool forming technique. The structures formed on pipe body <NUM> may be formed as a single unitary structure from a suitable metal material or a rigid polymer material.

Claim 1:
A hose connector structure comprising:
a rigid pipe body (<NUM>) having a frustoconical front end (<NUM>) extending outward from a tip end (<NUM>) to a radially enlarged first ring portion (<NUM>);
the first ring portion (<NUM>) having an annular face (<NUM>) extending at a constant diameter from the frustoconical front end and terminating at a circumferential first step (<NUM>), the first step (<NUM>) comprising tapering walls (<NUM>) extending from a rear edge of the first ring portion (<NUM>) annular face (<NUM>) and decreasing in diameter to a first step rear edge (<NUM>);
a radially reduced second ring portion (<NUM>) extending from the first step rear edge (<NUM>) at a constant diameter to a circumferential rear edge (<NUM>);
a circumferential second step (<NUM>) extending from the second ring portion circumferential rear edge (<NUM>) and comprising walls (<NUM>) that taper from said circumferential rear edge (<NUM>) in a decreasing circumferential diameter to a mid-section (<NUM>) of the pipe body (<NUM>); and
a flexible hose (<NUM>) adapted to be inserted by pressure over the pipe body (<NUM>) at the tip end (<NUM>) until it passes beyond the second step (<NUM>) to the mid-section (<NUM>) of the pipe body (<NUM>).