QUICK CONNECT TUBE COUPLING ASSEMBLY

Abstract: A quick connect tube coupling assembly includes a tube end assembly (ll) axially insertable into a coupling body assembly (l0), the latter including a body member (20) provided with a stepped bore therein to receive an elastomeric oil seal (30), a radially flanged retainer seat (3l), a split ring retainer (l6) and a hollow tube nut (35) threadingly received in the body member. The tube end assembly includes a straight walled tube (l2) having a lead-in chamfer (l4) at its free end and which is provided on its outer peripheral surface with a retainer receiving groove (l5) axially spaced apart from a second groove (l7) receiving a dust seal (l8) which is located so as to be wedged against an outwardly flared camming ramp wall (4l) at the outboard end of the tube nut during assembly of the tube end assembly into the coupling body assembly.

Description: This invention relates to tube couplings and, in particular, to a quick connect tube coupling assembly for use in hydraulic systems. Quick connect tube coupling assemblies, of the type which permit initial assembly by mere insertion of the end of a tube into a coupling body assembly, are well known in the art as disclosed, for example, in US patent nos 4,l33,564 and 4,l9l,408. Such assemblies usually provide a resilient seal ring sealingly engaged by the tube and a split ring lock system for the tube, the arrangement being such as to allow the threaded parts of the coupling assembly to be preassembled prior to insertion of the tube. The present invention relates to an improved quick connect tube coupling assembly wherein an oil seal, a retainer seat and a split ring retainer are axially retained in a stepped bore of a coupling body member by a tube nut threaded into the stepped bore, this coupling body assembly being adapted to receive a tube having axially spaced apart annular grooves, one of which is adapted to receive the split ring retainer and the other has a dust seal operatively positioned therein with the dust seal thus being located so as to abut against an opening defined by a camming ramp wall which is outwardly flared at the outboard end of the tube nut. It is therefore a primary object of the invention to provide an improved quick connect tube coupling assembly having a tube which is straight walled with axially spaced apart first and second annular grooves therein with a dust seal positioned in the latter annular groove that is adapted to be inserted into a coupling body assembly that includes an oil seal, a retainer seat and a split ring retainer axially retained in a stepped bore of a body member by a tube nut having a camming ramp wall which is outwardly flared at its outboard end for sealing engagement with the dust seal. Another object of the invention is to provide an improved quick connect tube coupling assembly wherein the tube is sealingly engaged at axially spaced apart locations by both an oil seal and a dust seal which are also operative to reduce pivotal movement of the tube relative to the normal axis of the coupling assembly. A further object of this invention is to provide an improved quick connect tube coupling assembly which allows for slight variations in manufacturing tolerances. To this end, a quick connect tube coupling assembly in accordance with the present invention is characterised by the features specified in the characterising portion of Claim l. For a better understanding of the invention as well as other objects and further features thereof, reference is had to the following detailed description of the invention to be read in connection with the accompanying drawings, in which:- Figure l is a side elevational view, partly in longitudinal section, of an assembled quick connect tube coupling assembly in accordance with the invention; and, Figure 2 is an exploded view of the quick connect tube coupling assembly of Figure l before insertion of the tube end assembly into the coupling body assembly of the coupling. Referring now to the drawings, the quick connect tube coupling assembly in accordance with the invention includes, in effect, a coupling body assembly l0, and a tube end assembly ll, both of which, as shown in Figure 2, can be assembled as sub-assemblies prior to insertion of the tube end assembly ll into the coupling body assembly l0 to the position shown in Figure l. Referring first to the tube end assembly ll, it includes a tube l2 which is straight walled with its free end provided with a lead-in chamfer l4 for a purpose to be described hereinafter. In addition tube l2 is also provided with a first annular groove l5 in its outer peripheral surface located a predetermined axial extent from the free end of the tube l2 so as to receive a portion of a split ring retainer l6 described further hereinafter, and a second annular groove l7 axially spaced from the first annular groove l5 a predetermined distance to receive a dust seal l8 which is an elastomeric 0-ring. In the construction illustrated, the first annular groove l5 is configured so as to receive a split ring retainer l6 that is of circular configuration when viewed in a cross-section thereof. However, it will be apparent to those skilled in the art that the first annular groove l5 can be suitably configured, if desired, to receive a split ring retainer of square or rectangular cross-sectional configuration. Preferably both annular grooves l5 and l7 are roll formed on the tube l2 in a manner well known in the art. The coupling body assembly l0 includes as an element thereof a body member 20, which can be a pump body, valve body or other element of a hydraulic systems or, alternatively it may be formed as a separate adapter nut for threaded connection to such an element of a hydraulic system. As shown, the body member 20 is provided with a stepped bore therein so as to define in succession, starting from the outboard end thereof, an outer internally threaded wall 2l, a first intermediate wall 22, a second intermediate wall 23, a tube receiving wall 24 and an inboard wall 25 defining a fluid passage, with these walls being of decreasing predetermined internal diameters in the order listed. First and second intermediate walls 22 and 23 are interconnected by a flat shoulder 26. Second intermediate wall 23 and tube receiving wall 24 are interconnected by a flat shoulder 27. Tube receiving wall 24 and inboard wall 25 are connected by an inclined shoulder 28. As illustrated, tube receiving wall 24 is of a suitable internal diameter so as to slidably receive the tube l2, while second intermediate wall 23 is of a suitable internal diameter so that an oil seal 30, in the form of an elastomeric 0-ring seal, can be located therein so as to sealingly abut against the second intermediate wall 23. In addition, the first intermediate wall 22 is sized so as to receive a retainer seat 3l, which is L-shaped and washer-like, therein. Retainer seat 3l includes an annular ring portion 32, of an external diameter corresponding to the internal diameter of first intermediate wall 22, with a radial annular flange washer 33 extending radially inward therefrom so that its inboard face can serve as a stop wall for the oil seal 30 when pressurized hydraulic fluid is present in the fluid passage defined by the inboard wall 25, with an opening 34 in this radial annular flange washer 33 being of a suitable internal diameter so as to slidably receive the tube l2. A tube nut 35 which is hollow and has a wrenching head 36 at its outboard end and an externally threaded shank 37 is threadingly engaged with the outer internally threaded wall 2l of the body member 20, and during assembly of the tube nut 35 to body member 20 it is torqued down so that its inboard end 38 is brought into abutment with the free end of the annular ring portion 32 of the retainer seat 3l to force it into abutment against the flat shoulder 26. The retainer seat 3l is thus positioned so as to define with the inboard end 38 of the tube nut 35 an annular groove of a suitable width and depth whereby it is adapted to loosely receive the split ring retainer l6, as shown in Figure 2, with the inboard end 38 of the tube nut 35 and outboard face of the radial annular flange washer 33 of the retainer seat 3l defining the spaced apart shoulders of the annular groove receiving the split ring retainer l6. The tube nut 35 is provided with a bore therethrough to define an internal tube receiving wall 40 at its inboard end of a diameter comparable to tube receiving wall 24 and coaxial therewith an outwardly flared or camming ramp wall 4l of a predetermined angle relative to the axis of the tube nut and of an internal diameter at the outboard or wrenching head 36 end of the tube nut 35 greater than the nominal outside diameter of the dust seal l8. During assembly of the tube end assembly ll into the coupling body assembly l0, from the position shown in Figure 2 to that shown in Figure l, the lead-in chamfer l4 of the free end of the tube l2 and the camming ramp wall 4l facilitates its entry into the internal tube receiving wall 40 of the tube nut 35, the camming ramp wall 4l then later serving to compress the dust seal l8, as shown in Figure l. Then as the lead-in chamfer l4 of the tube l2 enters the opening of the split ring retainer l6 and then the oil seal 30, it serves as a camming ramp to radially first expand the split ring retainer l6 so that it can slide over the tube l2 and to also compress the oil seal 30 radially outward so that it will ride onto the main body of the tube l2 into sealing engagement with the outer peripheral surface of the tube l2 and the second intermediate wall 23, as shown in Figure l. The tube end assembly ll is then further pressed axially into the coupling body assembly l0 until the split ring retainer l6 is in position to snap radially inward into the first annular groove l5 so that it can serve as an abutment shoulder means for abutment against the sides of the first annular groove l5 in the tube l2 and also for abutment against either of the opposed faces of the tube nut 35 and inboard face of the radial annular flange washer 33 to thereby limit further axial movement of the tube l2 in either direction. As will now be apparent, as the tube l2 is pushed to the position shown in Figure l, the dust seal l8 will enter the flared open end of the tube nut 35, so that the camming ramp wall 4l can act on this dust seal so as to radially compress the dust seal ring l8 whereby it will sealingly engage both the tube l2 and the camming ramp wall 4l. It will be appreciated that as the tube end assembly ll is axially pressed into the coupling body assembly l0, the oil seal 30 can move axially, as limited by flat shoulder 27, to another position than that shown in Figures l and 2. However, since the oil seal 30 is operative as a dynamic seal, as soon as pressurized hydraulic fluid is present in the fluid passage defined by the inboard wall 25, the oil seal will be axially moved by the pressure of the hydraulic fluid into sealing engagement with the inboard face of the radial annular flange washer 33, the position shown in Figure l. Thus during assembly of the tube end assembly ll into the coupling body assembly l0, the dust seal l8 is wedged into the camming ramp wall 4l angle of the tube nut 35 whereby to provide a seal to keep contaminates from entering the quick connect tube coupling assembly. Thus dust seal l8 is thus also operative to, in effect, preload the assembly by maintaining an axial force on the tube l2 caused by the angle of the camming ramp wall 4l on the tube nut 35 to resist axial movement of the tube l2. In addition since the tube l2, as then assembled to the coupling body assembly l0, is then sealingly engaged by both the oil seal 30 and by the dust seal l8 at axially spaced apart locations, possible pivotal movement relative to the axis of the stepped bore in the body member 20 is substantially eliminated. As should now be apparent to those skilled in the art, disassembly of the coupling assembly shown in Figure l is accomplished by first removing the tube nut 35.

Claims: 1. A quick connect tube coupling assembly including a coupling body member (l0), a tube (l2) which is straight walled, a retainer seat (3l), a split ring retainer (l6), an oil seal (30), and a tube nut (35); the coupling body member having a stepped bore extending from an outboard end thereof to define an internally threaded wall (2l), a first intermediate wall (22), a second intermediate wall (23), a tube receiving wall (24) and a fluid passage; the oil seal being operatively positioned in the coupling body member to sealing engage the second intermediate wall and the tube; the retainer seat being operatively received by the first intermediate wall, the tube nut being threadingly received in the internally threaded wall so as to abut against the retainer seat, the retainer seat having a radial annular flange washer (33) to receive the tube and to define on one side thereof an abutment shoulder for the oil seal and on the other side thereof defining with an inboard end face of the tube nut an annular groove in which the split ring retainer is operatively positioned; the tube having a lead-in chamfer (l4) at its free end, and a first annular groove (l5) for the split ring retainer located a predetermined distance from the free end of the tube; and the tube nut having a bore extending therethrough defining an internal tube receiving wall (40) at its inboard end and a camming ramp wall (4l) which is outwardly flared at its outboard end; characterised in that the tube (l2) also has a second annular groove (l7), receiving a dust seal (l8), located a predetermined distance from the first annular groove (l5), the dust seal (l8) being sealing compressed between the camming ramp wall (4l) and the tube (l2). 2. A quick connect tube coupling assembly as claimed in Claim l, characterised in that the tube receiving wall (24) is interconnected to the second intermediate wall (23) by a flat shoulder (27), and the fluid passage is interconnected to the tube-receiving wall by an inclined shoulder (28), the walls (2l-24) of the stepped bore being of progressively reduced internal diameters relative to the internally threaded wall (2l), the oil seal (30) being positioned next adjacent to the flat shoulder (27); in that the radial annular flange washer (33) has an internal diameter corresponding to the internal diameter of the tube receiving wall (24); in that the tube nut (35) has a wrenching head (36) with an externally threaded shank (37) extending therefrom; and in that the tube (l2) has a nominal external diameter whereby it is adapted to be slidably received in the bore of the tube nut (35) and the tube receiving wall (24) of the coupling body assembly (l0).

Inventors: CUNNINGHAM, GAIL M.
Applicants: GENERAL MOTORS CORPORATION
Application year: 1986
Main classification: F16L37
IPC codes: F16L37