All plastics quick-connect coupling

Abstract: A coupling assembly entirely formed from plastics material is provided for selectively connecting and disconnecting first and second fluid lines. A male coupling member (B) includes an external groove (22) that receives a radially inward extending shoulder (58) of the sleeve (D). An external groove (46) on a female coupling member (c) is selectively engaged by latching tabs (76) extending radially inward from the sleeve (D). The latching tabs (76) are selectively pivotable radially outward by depression of release buttons (100). The pivoting action of the latching members (72) is defined along a central portion (74) in which circumferential strips (84, 86) undergo a twisting action.

Description: This invention pertains to the art of couplings and more particularly to quick-connect/disconnect couplings for fluid lines. The invention is particularly applicable to a plastics quick-connect coupling particularly useful in the biotechnological and biomedical fields and will be described with particular reference thereto. However, it will be appreciated that the invention has broader applications and may be advantageously employed in other environments and applications. When handling biotechnological materials, it is necessary to maintain an ultra-clean environment that will not adversely react with the fluid material. Thus, use of any metal components is avoided. Unfortunately, many of the desired properties of known fluid coupling assemblies are not available in plastics coupling assemblies. Still another goal in designing coupling arrangements is that the latching arrangement be simple and easy to use. In an effort to overcome some of the problems associated with prior plastics quick-connect couplings, manufacturers have designed complex latching arrangements that are difficult to manufacture and use. There is known from GB-A-2091365 a tube coupling comprising a tubular male coupling member, a tubular female coupling member and an intermediate ring carrying a longitudinally extending latching arm. The ring has a continuous annular body portion which is dimensioned so as to be a snap-fit into an external annular groove on either the male or female coupling member. The latching arm has an inwardly extending hook portion which is adapted to engage a flange on the female or male coupling member for holding the male and female members together in the axial direction whilst allowing them to rotate one relative to the other. The latching arm is deformable by finger pressure in order to bring its hook out of engagement with the flange. A problem with this known device is that, because the whole of the continuous annular body portion of the ring is to be a snap-fit in the groove of the male or female coupling member, it must be stretched radially in order to pass it over the larger diameter body of the male/female coupling member so as to arrive at the snap-fit position in the smaller diameter groove. This makes fitting of the ring a difficult operation. It would be desirable, therefore, to provide a plastics quick-connect coupling that is not only easy to manufacture, but is easy to assemble and use. According to the present invention, there is provided a coupling assembly for selectively coupling first and second fluid lines together, the coupling assembly including a male coupling member adapted to be connected to a first fluid line at one end and having a circumferential groove defined on an external surface, a female coupling member adapted to be selectively connected to a second fluid line at one end and having a circumferential groove defined on an external surface, and a cylindrical sleeve member, adapted to be connected to one of the male and female members, which includes a latching member having a locking tab adapted for selective receipt in one of the grooves defined on the male and female members, the latching member being pivotable about an intermediate central portion by depressing an actuating portion defined at one end of the latching member, one end of the cylindrical sleeve being substantially circumferentially continuous and wherein the other end of said sleeve has circumferentially interrupted regions and a shoulder which extends radially inwardly from the internal diameter of the sleeve which is thereby adapted for receipt by a snap-fit of the male and female members. Preferably the latching member includes circumferentially extending strips that are subjected to twisting forces upon pivoting action of the latching member. The sleeve can be circumferentially continuous at one end and adapted to receive both the male and female coupling members therein. Preferably, all of the coupling components are made entirely of plastics material. The invention is described further hereinafter, by way of example only, with reference to the accompanying drawings, in which:- Figure 1 is a longitudinal cross-sectional view of the components of one embodiment of a coupling assembly in accordance with the present invention, shown in a disconnected arrangement; Figure 2 is a longitudinal cross-sectional view similar to Figure 1 but illustrating the coupling components in a connected arrangement; Figure 3 is a perspective view of the coupling sleeve of the quick-connect assembly; Figure 4 is a top plan view of the coupling sleeve of Figure 3; Figure 5 is a longitudinal cross-sectional view of the coupling sleeve; Figure 6 is an end elevational view taken from the left-hand side of Figure 5; Figure 7 is an elevational view taken from the right-hand side of Figure 5; Figure 8 is a perspective view of the male coupling member; Figure 9 is a longitudinal cross-sectional view of the male coupling member; Figure 10 is a cross-sectional view taken generally along the lines 10-10 of Figure 9; Figure 11 is a cross-sectional view taken generally along the lines 11-11 of Figure 9; and Figure 12 is an end view of the male coupling member taken generally along the lines 12-12 of Figure 9. The drawings show a coupling assembly A which includes a male coupling member B and a female coupling member C. A coupling sleeve D is fixedly secured to one of the coupling members, which in the preferred embodiment is the male coupling member, and selectively connects the male and female coupling members together. More particularly, and as shown in Figures 1, 2 and 8-12, the male coupling member B is formed entirely of plastics material, for example polysulfone. A first end 10 of the male coupling member is adapted for receipt in a first fluid line F which is illustrated in phantom. A second end 12 of the male coupling member is received in the coupling sleeve D and adapted for selective connection with the female member as will be described below. A reduced diameter region 14 and raised land 16 at the first end are adapted to securely receive the first fluid line thereover. An external clamping means (not shown) can be used to maintain a secure fit between the first fluid line and the male coupling member in a manner well known in the art. Since the clamping arrangement forms no part of the subject invention, further discussion herein is deemed unnecessary. The coupling member includes a through opening or bore 18 for fluid passage therethrough. The bore may include valving means (not shown) to selectively shut off fluid flow if desired, particularly when the male and female coupling members are disconnected. Adjacent the second end of the male coupling member are a shoulder 20 and external groove 22. The shoulder and groove cooperate with the coupling sleeve to fixedly secure the sleeve and male coupling member together as will be described in further detail below. A second, reduced diameter groove 24 is disposed between the shoulder and second end. The second groove 24 receives a seal member such as O-ring 26 therein. The O-ring is sized so that its inner diameter closely grips the second groove while its outer diameter, in an uncompressed state, extends radially outward from the second end of the male coupling member. Thus, and as is more apparent in Figure 2, when the coupling assembly is made up, the O-ring is radially compressed and axially expands to substantially fill the second groove 24. This assures a tight, secure seal between the male and female coupling members. The female coupling member also includes a first end 30 adapted for receipt in a second fluid line F'. As similarly described with respect to the male coupling member, a reduced diameter region 32 and raised land 34 are adapted to tightly secure the female coupling member in the second fluid line. Again, an external clamping member (not shown) can be used to secure the fluid line to the female coupling member. A second end 36 of the female coupling member includes an enlarged counterbore 38 that is coaxial with throughbore or passage 40. Preferably, the counterbore includes an internally tapered region 42 at its outer end that facilitates receipt of the female coupling member over the external diameter of O-ring 26. The tapered region ramps the female coupling member over the O-ring and facilitates insertion over the second end 12 of the male coupling member. An external tapered surface 44 is also provided at the second end of the female coupling member for reasons which will become more apparent below. An external groove 46 is defined adjacent the second end of the female coupling member. This external groove facilitates locking connection of the coupling members. As best illustrated in Figure 2, the groove is axially spaced from the end of the female coupling member so that sealing engagement is first established between the coupling members B, C. Thereafter, and upon further axial advancement of the coupling members from the position shown in Figure 1 to that shown in Figure 2, the coupling sleeve engages the groove 46. Fluid communication is then established between the bores 18, 40. With continued reference to Figures 1 and 2, and additional reference to Figures 3 - 7, the third component of the coupling assembly, namely the coupling sleeve D, will be described in greater detail. It, too, is also formed entirely of plastics material, preferably polysulfone. It will be understood, though that other alternative plastics materials can be used without departing from the scope and intent of the present invention. The coupling sleeve is defined by a substantially cylindrical member 50 having opposed first and second ends 52, 54 thereof. The second end 54 is circumferentially continuous to provide added strength to the coupling assembly. The first end 52, on the other hand, has circumferentially interrupted regions for reasons which will be addressed below. The internal diameter 56 of the sleeve is dimensioned to freely, but closely, receive the second end of the female coupling member. Additionally, a radially inwardly extending shoulder 58 is disposed at the first end 52 of the sleeve and has an inner diametrical dimension substantially the same as that of external groove 22 on the male coupling member. In this manner, the sleeve can be inserted over the first end 10 of the male coupling member and advanced axially toward the second end 12 until the shoulder 58 snaps into engagement in groove 22. The shoulder 58 of the coupling sleeve abuts radially outward extending shoulder 20 of the male coupling member to limit further axial advancement of the sleeve toward the second end 12. A means for latching the female coupling member to the male coupling member is integrally defined on the sleeve. More specifically, the latching means is defined by two, diametrically opposed latching members 72, 72'. The latching members are identical in construction so that description of one is applicable to the other unless specifically noted otherwise. The latching member pivots about a generally central portion 74. A latching tab 76 is defined adjacent the second end of the sleeve and extends radially inward so that the dimension "d" defined between the latching tabs 76, 76', in a relaxed position, is substantially less than that of the inner diameter 56 of the sleeve (Figure 5). Each latching tab includes a bevelled edge 78 that cooperates with externally tapered region 44 at the second end of the female coupling member to ride over and snap radially inward into groove 46. That is, as the male and female coupling members are brought into sealing engagement, the latching tabs slide along the tapered region 44 and then snap radially inward into groove 46. This locks the female coupling member against axial movement relative to the male coupling member. As the latching tabs slide over the external tapered region 44, the entire latching member pivots about the central portion 74. More specifically, circumferentially extending strips 84, 86 are defined by circumferential slot pairs 88, 90. The strips only extend partially around the circumference of the coupling sleeve as is apparent in Figures 3 and 4. One of the circumferential slots 88 intersects longitudinal slot 92 on one side of the strip 84 while the other slot intersects an irregular longitudinal slot 94 that extends to sleeve end 52. Likewise, circumferential slots 90 intersect longitudinal slots 96, 98 on either axial side of the strip 86. According to the preferred arrangement, and as best shown in Figure 3, the circumferential strips have a substantially reduced thickness or radial dimension relative to the remainder of the sleeve. This provides ideal twisting action with sufficient reinforcement at the areas of intersection of the strips with the rest of the sleeve. The longitudinal slots 94, 98 extend radially through the cylindrical member 50 at the first end 52 so that an actuating portion or release button 100 can be depressed radially inward relative to the sleeve. Depressing the buttons radially inward pivots the latching tabs 76 radially outward. This pivoting action places the circumferential strips 84, 86 under a twisting load, which is distributed along the strips to prevent plastic deformation of the sleeve material. The latching member is reinforced along its longitudinal extent and as most apparent in Figures 3 and 5. The latching member has increased mass for strength and rigidity purposes so that depression of the release button results in a well defined pivoting action about the central portion 74 and circumferential strips 84, 86 to move the latching tabs to a release position. Once the depression force is released, the memory of the plastics material urges the latching tabs radially inward and the release buttons 100 radially outward to the normal, locked position shown in Figure 5. As is most apparent in Figure 4, the release button extends axially beyond the end 52 of the sleeve. Preferably the actuating portion 100 also has a substantially larger lateral or circumferential dimension than the remainder of the latching member. This provides sufficient surface area to accommodate an operator's fingers to effectively depress the release buttons and move the latching tabs outward. As best shown in Figures 6 and 7, the shoulder 58 of the sleeve is circumferentially interrupted at diametrically opposite regions 110, 112. These regions cooperate with keyed portions 114, 116 defined by radial flanges on the male coupling member (Figures 8 and 10). The lateral or circumferential dimension of these keyed portions is slightly less than the circumferential extent of the regions 110, 112. Thus, when the coupling sleeve is placed over the first end 10 of the male coupling and advanced toward the second end 12, the keyed portions 114, 116 and regions 110, 112 must be aligned to force the sleeve over shoulder 20 of the male coupling member. Circumferential recesses 118, 120 are also preferably provided on the male coupling member as illustrated in Figure 11. The recesses permit the latching members 72, 72', particularly the latching tabs 76, 76', to advance axially past shoulder 25 during assembly of the coupling sleeve over the shoulder 20. Once the coupling sleeve shoulder 58 is received in groove 22, the sleeve is free to rotate relative to the male coupling member and is axially retained between shoulders 22 and 23.

Claims: A coupling assembly for selectively coupling first and second fluid lines together, the coupling assembly including a male coupling member (B) adapted to be connected to a first fluid line at one end (10) and having a circumferential groove (22) defined on an external surface, a female coupling member (C) adapted to be selectively connected to a second fluid line at one end (30) and having a circumferential groove (46) defined on an external surface, and a cylindrical sleeve (D) member, adapted to be connected to one of the male and female members, which includes a latching member (72) having a locking tab (76) adapted for selective receipt in one of the grooves (22, 46) defined on the male and female members, the latching member (72) being pivotable about an intermediate central portion (74) by depressing an actuating portion (100) defined at one end of the latching member, one end (54) of the cylindrical sleeve (D) being substantially circumferentially continuous and characterised in that the other end (52) of said sleeve has circumferentially interrupted regions and a shoulder (58) which extends radially inwardly from the internal diameter (56) of the sleeve which is thereby adapted for receipt by a snap-fit in the other one of the grooves (22, 46) of the male and female members. A coupling assembly as claimed in claim 1, further comprising longitudinal slots extending on opposite axial ends of the central portion (74) to facilitate the pivoting action of the latching member (72). A coupling assembly as claimed in claim 1 or 2, further comprising circumferential slots (88) extending on opposite lateral sides of the central portion (74) to facilitate the pivoting action of the latching member (72). A coupling assembly as claimed in claim 3, when appendent to claim 2, wherein the longitudinal and circumferential slots intersect adjacent the central portion (74) of the latching member. A coupling assembly as claimed in claim 1, wherein the actuating portion (100) of the latching member extends axially beyond the sleeve (D). A coupling assembly as claimed in any of claims 1 to 5, wherein the latching member (72) includes a reinforced ridge that extends radially outward from the remainder of the sleeve (D) to provide rigidity to the latching member. A coupling assembly as claimed in any of claims 1 to 6, further comprising a seal member (26) received on an external portion of the male member (B) for sealing engagement with the female member when disposed in coupled relation. A coupling assembly as claimed in any of claims 1 to 7 wherein the sleeve (D) is formed entirely of a plastics material. A coupling assembly as claimed in any of claims 1 to 8, wherein the actuating portion (100) of the latching member has a substantially larger circumferential dimension than the locking tab (76). A coupling assembly as claimed in claim 9, wherein the latching member is attached to the sleeve along a circumferential strip (84, 86) that is perpendicular to the axial extent of the latching member. A coupling assembly as claimed in claim 9 or 10 wherein the latching means includes a second latching member (72') diametrically opposed on the sleeve from the first latching member (72). A coupling assembly as claimed in claim 9, 10 or 11 further comprising means for keying the coupling sleeve and the male coupling member together during assembly. A coupling assembly as claimed in claim 12 further comprising means for locking the coupling sleeve against axial movement and permitting rotational movement relative to the male coupling member. A coupling assembly as claimed in claim 1, further comprising longitudinally and circumferentially extending pairs of slots (92, 94; 88, 90) that intersect adjacent the central portion (74) of the sleeve (D) so that the central portion (74) is adapted for pivoting action by placing circumferential strips (84, 86) interposed between the circumferential slots (88, 90) under twisting forces when the latching member is pivoted.

Inventors: KRECZKO GREGORY, MEDVICK RICHARD J, WAGNER ROSS L, KRECZKO, GREGORY, MEDVICK, RICHARD J., WAGNER, ROSS L.
Applicants: SWAGELOK QUICK CONNECT CO, SWAGELOK QUICK-CONNECT CO.
Application year: 1991
Main classification: F16L37
IPC codes: F16L37