Quick locking pipe joint for round, plain, or profiled pipe

[0002] This application claims the benefit of provisional patent Application No. 60/139,910, filed Jun. 17, 1999, the benefit of which is hereby claimed under 35 U.S.C. § 119.

[0003] This invention relates to apparatus for joining pipes, and in particular, to piping joints that are indexable and that can be disassembled.

[0004] Pipes and piping systems are useful in a wide variety of applications. Piping systems for transporting or routing solids, liquids and gasses, for example, are virtually ubiquitous throughout home and industry. When installing a piping system, individual pipes are typically acquired, in set lengths, and must be assembled by cutting and joining the pipes to produce the desired piping configuration. Different applications may present different pipe joint requirements. In most applications it is important that the pipe joints be strong, so that they do not become a failure point for the piping system. This is particularly important when the joints are not easily accessible. In some applications, easy disassembly of the piping joint is desirable, for example in applications where the piping system is temporary and will ultimately be removed, or in order to accommodate difficulties that might be encountered during field assembly. Also, in many applications it is important that the pipe joints be sealed, either to prevent whatever is in the piping system from leaking out, or to prevent external fluids from leaking into the pipe system, or both.

[0005] It is sometimes desirable to have a pipe joint that will rotationally index the pipes being joined. For example, inclinometers are frequently used in geological applications to detect movement of a hillside or other geologic formation. Inclinometers measure inclination relative to the vertical axis, and periodic measurements taken along a conduit installed in the ground can be compared to detect changes. Typically a plastic pipe conduit is installed in a bore hole in a generally vertical orientation. The plastic pipe conduit includes oppositely disposed longitudinal grooves along its inner surface that provide a track for the inclinometer, which records inclination while being lowered through the plastic conduit. Because the profiled pipe conduit is constructed by joining a number of separate pipes, the individual pipes must be rotationally aligned, or indexed, so that the longitudinal grooves in the profiled pipes form a continuous track along the length of the pipe conduit.

[0006] Many different systems have been developed to facilitate assembling and joining pipes, which systems may be more or less suitable for any given application. For example, home water systems employing copper piping is typically installed using sleeve joint elements that are soldered to the pipe. This produces a strong, reliable and generally permanent pipe joint. Home irrigation systems, on the other hand, typically employ plastic piping that is joined using male and female joint elements that are glued together. This type of piping system is very flexible, easily installed and relatively inexpensive. Neither of these methods allow for easy disassembly of the piping joints.

[0007] A threaded joint for tubular plastic parts is disclosed in U.S. Pat. No. 5,906,398 to Larsen et al. Larsen et al. teaches the use of helical threads wherein at least one of the threads terminates abruptly, creating a transverse end-surface that can be located at a predetermined position. This end-surface functions as a stop, whereby the pipes are rotationally oriented in a desired manner when the joint elements are fully screwed together. It may be difficult, however, to control the fabrication of threads well enough to achieve precise rotational control over the joined pipes. In addition, difficulties may arise in field applications where dirt and other foreign matter may interfere with the threaded joint, or may prevent the joint from fully closing thereby failing to accomplish the desired rotational orientation.

[0008] In U.S. Pat. No. 5,015,014 to Sweeney, a plastic pipe section is disclosed wherein matching internal and external rabbets are formed on the pipes to be joined, and the pipes are pressed together. An optional clamp may be installed around the joint to help strengthen the joint. This type of joint, which relies on the flexibility of the pipe to allow the interlocking ribs to pass each other, may not provide a sufficiently strong joint for certain applications. Also, the force required to join the pipes in interlocking fashion may make assembly difficult or require special tools, and dirt encountered in the field may interfere with assembly of the joint.

[0009] U.S. Pat. No. 5,915,738 to Guest and U.S. Pat. No. 5,029,904 to Hunt both disclose pipe joints wherein one pipe is provided with a circumferential ridge and the mating pipe is provided with a mating cup or fingers having a lip that engages the circumferential rib to hold the pipes together. These types of joints may not provide sufficient strength for certain applications, and result in a joint having a diameter greater than the diameter of the pipe, which may be undesirable.

[0010] In U.S. Pat. No. 5,176,406 to Straghan, a pipe coupling is disclosed for joining pipes in end-abutting relation comprising a sleeve having outwardly deflectable segments that engage circumferential grooves on each of the pipes. In addition, an additional slot is provided on the coupling member to engage a raised button provided on the pipes, thereby allowing the pipes to be rotationally aligned in a predetermined orientation. Joints of this type may not be strong enough for certain applications, and the joint will have a larger diameter than the pipes. The joint is also difficult to disassemble. The slot is also susceptible to being clogged by dirt and other foreign matter encountered in the field, interfering with pipe assembly. Also, the longitudinal slots at the joint will weaken the torsional rigidity of the joint, which could result in a weaker joint and/or rotational misalignment of the pipes.

[0011] There is a need for a strong pipe joint that is sufficiently robust to tolerate dirt that may be encountered in the field, and that can be disassembled. There is also a need for a robust pipe joint that is indexable.

[0012] The present invention is directed to a joint for connecting pipes comprising a male joint member having a plurality of outwardly-extending locking tabs at its distal end and a female joint member having a plurality of inwardly-extending locking tabs spaced between its distal and proximal ends, wherein the outwardly-extending locking tabs can slide past and then be rotated to a position behind the inwardly-extending locking tabs such that the locking tabs prevent relative axial motion between the male and female joint members. In another aspect of the invention, the joint further comprises a rotational locking apparatus that engages to prevent relative rotational motion between the male and female joint members.

[0013] According to another aspect of the invention, the rotational locking apparatus comprises a locking pin having a cylindrical portion extending outwardly from the male joint member that engages a circular aperture on the female joint member.

[0014] In one embodiment, the locking pin has a chamfered profile whereby the female joint member can more easily slide over the locking pin.

[0015] In yet another aspect of the invention, the locking tabs further comprise interlocking reverse-chamfered edges wherein the inwardly-extending locking tabs radially interlock with the outwardly-extending locking tabs.

[0016] In still another aspect of the invention, the male joint member may further comprise internal longitudinal grooves that match longitudinal grooves in the pipes that are to be connected.

[0017] In another aspect of the invention, the joint may further include an O-ring that is installable to seat between the male joint member and the female joint member.

[0018] The foregoing aspects and many of the attendant advantages of this invention will become more readily appreciated as the same become better understood by reference to the following detailed description, when taken in conjunction with the accompanying drawings, wherein:

[0019] FIG. 1 is a perspective view of a disassembled pipe joint in accordance with the present invention;

[0020] FIG. 2 is a front view of the pipe joint shown in FIG. 1, in an assembled configuration;

[0021] FIG. 3 is a front sectional view of the female joint member of the pipe joint shown in FIG. 1;

[0022] FIG. 4 is a front view of the male joint member of the pipe joint shown in FIG. 1;

[0023] FIG. 5 is a partial, cutaway view of the male joint member and female joint member of the pipe joint shown in FIG. 1;

[0024] FIG. 6 is a perspective view of the locking pin component shown in FIG. 1;

[0025] FIG. 7 is a partial exploded cutaway side view of locking pin of FIG. 6 showing also the locking pin aperture in the male joint member;

[0026] FIG. 8 is a side view of the pipe joint shown in FIG. 1, with the male joint member partially inserted into the female joint member wherein the chamfered edge of the locking pin is oriented to accommodate the female joint member;

[0027] FIG. 9 is a side view of the pipe joint shown in FIG. 1, with the joint fully engaged, and with the chamfered edge of the locking pin oriented to facilitate disassembly of the joint;

[0028] FIG. 10A is a front view of a male joint member of the present invention shown in FIG. 1, applied to the profile pipe;

[0029] FIG. 10B is a front view of a female joint member of the present invention shown in FIG. 1, applied to a profiled pipe; and

[0030] FIG. 11 is a perspective view of a single one of either of the pipes shown in FIG. 1, showing the joint members on opposite ends.

[0031] While the preferred embodiment of the invention has been illustrated and described, it will be appreciated that various changes can be made therein without departing from the spirit and scope of the invention.

[0032] Referring now to the drawings, wherein like numbers indicate like parts, FIG. 1 is a perspective view of a disassembled pipe joint in accordance with the present invention. The joint comprises a male joint member 200 and a corresponding female joint member 300. In the disclosed embodiment, the male joint member 200 and the female joint member 300 are integrally formed on opposite ends of a pipe 100 as shown in FIG. 11. It is contemplated, however, that the present invention could also be practiced in other configurations, for example, as separate components that are attached to the ends of standard pipes.

[0033] As seen most clearly in FIG. 1, the male joint member 200 comprises a first tubular portion 201 and a second tubular portion 202. The first tubular portion 201 extends axially from the pipe 100 and has an inside diameter that matches the inside diameter of the pipe 100, and an outside diameter that is less than the outside diameter of the pipe 100. The second tubular portion 202 extends axially from the distal end of the first tubular portion 201 and has an inside diameter matching the inside diameter of the pipe 100, and an outside diameter that is less than the outside diameter of the first tubular portion 201.

[0034] Four outwardly extending locking tabs 210 project radially from the distal end of the second tubular portion 202. The locking tabs 210 are angularly spaced along a narrow axial portion of the circumference of the second tubular portion 202. Although four locking tabs are shown in the embodiment illustrated in FIG. 1, it is contemplated that more or fewer locking tabs could also be used. It is also contemplated that multiple rows of longitudinally-spaced locking tabs could alternatively be provided to produce an even stronger joint. The locking tabs 210 project outwardly to a diameter that is approximately equal to the outside diameter of the first tubular portion 201.

[0035] As seen most clearly in FIG. 4, in the illustrated embodiment the locking tabs 210 have a back edge 212 that is reverse chamfered. The junction 220 between the pipe 100 and the male joint first tubular portion 201 is also optionally provided with a reverse chamfer. Alternatively, if the female joint member 300 must flex outwardly to accommodate a locking pin 250, the junction 220 may not be chamfered. The male joint member 200 also has a locking pin 250 rotatably mounted in the first tubular portion 201 as discussed in more detail below.

[0036] As seen most clearly in FIG. 3, the female joint member 300 has a third tubular portion 303 that extends axially from the pipe 100, from the pipe end opposite the male joint member 200. The third tubular portion 303 has an outside diameter generally matching the outside diameter of the pipe 100, and an inside diameter that is approximately equal to the outside diameter of the male joint first tubular portion 201. Four inwardly extending locking tabs 310 are disposed on the inner surface of the third tubular portion 303. The inwardly extending locking tabs 310 are located an axial distance from the junction between the pipe 100 and the female joint member 300 that is approximately equal to the axial length of the outwardly extending locking tabs 210 on the male joint member 200.

[0037] The inwardly extending locking tabs 310 project inwardly to a diameter that is approximately equal to the outside diameter of the second tubular portion 202. The inwardly extending locking tabs 310 have a width and are angularly spaced such that they can slidably pass between the outwardly extending locking tabs 210 when the male joint member 200 is inserted into the female joint member 300 and the joint members 200, 300 are in a first position wherein the inwardly extending locking tabs 310 are aligned with the gaps between the outwardly extending locking tabs 210.

[0038] It will be appreciated that when the male joint member 200 is fully inserted into the female joint member 300, the joint members 200, 300 can be rotated relative to each other to a second position wherein the outwardly extending locking tabs 210 are aligned directly behind the inwardly extending locking tabs 310, as shown in FIG. 2. It will also be appreciated that the inwardly extending locking tabs 310 radially overlap the outwardly extending locking tabs 210, and that the overlapping locking tabs will thereby prevent significant relative axial motion between the joint members 200, 300. FIG. 5 shows an exploded partial sectional view of the male joint member 200 and the female joint member 300, illustrating the axial orientation of the locking tabs 210, 310 when the joint is assembled. As shown in FIGS. 1 and 2, the length of the third tubular portion 303 is preferably approximately equal to the combined length of the first tubular portion 201 and second tubular portion 202.

[0039] As seen most clearly in FIG. 3, in the illustrated embodiment the inwardly extending locking tabs 310 have a back edge 312 that is reverse chamfered. The reverse chamfer on the back edge 312 is shaped to engage the reverse chamfer on the back edge 212 of the outwardly extending locking tabs 210 when the joint members are rotated to the second position. As also seen in FIG. 3, the front edge 320 of the third tubular portion 303 may optionally be provided with a chamfer that is shaped to engage the reverse chamfer at the junction 220 between the pipe 100 and the male joint first tubular portion 201. A locking pin aperture 350 is provided through the female joint member 300 that is sized to slidably accommodate the locking pin 250 and located axially and circumferentially on the third tubular portion 303 whereby the locking pin 250 will engage the locking pin aperture 350 when the joint members 200, 300 are in the second position. It will be appreciated when the locking pin 250 engages the locking pin aperture 350, the male joint member 200 and female joint member 300 will be locked from rotating with respect to each other.

[0040] An O-ring groove 203 can optionally be provided in the first tubular portion 210 of the male joint member 200. An O-ring 110 can then be installed on the O-ring groove 203, to provide a seal between the joint members 200, 300 when the joint is assembled.

[0041] A preferred locking pin 250 is shown in FIG. 6. The locking pin 250 is generally cylindrical in shape and has an enlarged circular base portion 258. A keyed aperture 256 is provided at the top of the pin 250 generally at the axis. The top surface of the pin 250 includes a flat portion 252 and a chamfered portion 254. The looking pin 250 is rotatably mounted in the first tubular portion 201 of the male joint member 200. As seen most clearly in FIG. 7, a mounting orifice 260 is provided for the locking pin 250 in the first tubular portion 201. The mounting orifice 260 has an enlarged lower portion 262 sized to accommodate the lower portion 258 of the locking pin 250, whereby the locking pin 250 can be pressed into the mounting orifice 260, and will be retained therein by the enlarged base portion 258. It will be appreciated that the locking pin 250 can therefor be rotated axially within the mounting orifice 260, most conveniently by using a tool that engages the keyed aperture 256.

[0042] FIG. 8 shows the configuration of the male joint member 200 and female joint member 300 partially assembled. The locking pin 250 is oriented with the chamfered portion 254 facing toward the female joint member 300, whereby the flexibility of the female joint member 300 and/or the locking pin 250 will allow the tubular portion 302 to slide up the chamfered portion 254 and over the locking pin 250. When the male joint member 200 and the female joint member 300 are rotationally oriented in the first position, as shown in FIG. 8, the outwardly extending locking tabs 210 are offset from the inwardly extending locking tabs 310 whereby the locking tabs 210, 310 can slide past each other axially. When the female joint member 300 and male joint member 200 are further pushed together such that the front edge of the female joint member 320 is adjacent the junction between the male joint member 200 and the pipe 100, the joints 200, 300 can be rotated to the second position, whereby the locking pin aperture 350 will slidably engage the locking pin 250. When the locking pin aperture 350 has engaged the locking pin 250, the outwardly extending locking tabs 210 are behind the inwardly extending locking tabs 310 and the joint is axially locked in place. The joint is also rotationally locked by the locking pin 250. It will be apparent that although the locking pin 250 also axially locks the joint, the strength of the axial support provided by the locking pin 250 and locking pin aperture 350 is less strong than the axial support from the locking tabs 210, 310.

[0043] FIG. 9 shows the assembled joint with the locking pin 250 rotated ninety degrees from the position shown in FIG. 8, such that the chamfered portion 254 is oriented circumferentially. This locking pin 250 orientation would be selected if the pipe joint is to be disassembled. When the locking pin 250 is oriented as shown in FIG. 9, the flexibility of the third tubular portion 303 and/or the locking pin 250 will permit the third tubular portion 303 to slide over the top of the locking pin 250, and the male joint member 200 and female joint member 300 may be rotated back to the first position, wherein the locking tabs 210, 310 are offset, and the joint members 200, 300 can be axially pulled apart to disassemble the joint.

[0044] Although the preferred embodiment of a locking pin has been disclosed, it is contemplated there are many other locking pin configurations that are alternatively acceptable for the current application. For example, rather than providing a rotatable, chamfered locking pin, a locking pin that is spring loaded in the male pipe member could be used, wherein the locking pin is simply depressed into an orifice (similar to mounting orifice 260) for assembly or disassembly of the pipe joint. Alternatively, a locking pin that is spring-loaded longitudinally could be provided on the male joint member, with a mating slot on the female joint member, wherein when the joint members are pushed together the locking pin will retract longitudinally, and then when the joints are rotated into the desired alignment, the locking pin would engage the slot in the female joint member. These, and other equivalent locking pin configurations could be used without departing from the present invention. It is also contemplated that the present invention could be practiced in applications where rotational alignment is not important, and wherein no locking pin is used.

[0045] The present invention is particularly suited to applications wherein the pipe to be joined is profiled, that is, when the pipe has interior features, such as grooves, that must be properly aligned. FIGS. 10A and 10B show front views of the male joint member 200 and the female joint member 300, wherein the pipe to be joined has two pairs of oppositely disposed longitudinal internal grooves 120. The male joint member 200, which has an inside diameter matching the inside diameter of the pipe 100, also preferably continues the internal grooves 120 on the interior surface. In the disclosed embodiment, the locking tabs 210 are located directly over the grooves 120, so that the extent of the minimum wall thickness is reduced.

[0046] As will be apparent to those skilled in the art in the light of the foregoing disclosure, many alterations and modifications such as different materials, profiles, numbers of locking tabs, numbers of locking pins and the like are possible in the practice of this invention without departing from the spirit or scope thereof. Accordingly, the scope of the invention is to be construed in accordance with the substance defined by the following claims.