Pipe preparation device

A pipe preparation device is disclosed for chamfering pipe ends and placing witness marks thereon to provide a visible indication that the pipes are properly engaged with a coupling. The device includes a body having co-axially aligned receptacles at opposite ends, the receptacles being sized to receive pipes having different diameters from one another. Cutting blades are mounted on the body and project into each receptacle. The blades have cutting edges that engage the end of a pipe inserted into a receptacle and cut a chamfer when the body is rotated relatively to the pipe. Two scoring tools project into each receptacle. The tools have contact surfaces that engage a pipe inserted into the receptacle. The tools in each receptacle are offset from one another and form two circumferential grooves around the pipe when the body and pipe are rotated relatively to each other. The grooves act as witness marks.

FIELD OF THE INVENTION

This invention concerns tools for preparing pipes for joining to one another, and especially for pipes joined using mechanical pipe couplings.

BACKGROUND OF THE INVENTION

Pipes, especially relatively small diameter copper pipes between one half inch and two inches nominal diameter, are used extensively to provide water service for homes, business and industry. Such pipes may be sealingly joined to one another end to end using mechanical couplings to create a piping network for conveying water throughout a building such as a home, office or factory.

Mechanical couplings provide various advantages over traditional solder joints for connecting pipes in that they avoid the use of acid flux, solder and open flame to effect a connection. Assembly of a joint using a mechanical coupling also requires less time than a solder joint and may be performed by a less skilled worker. Assembly of a joint merely requires that a pipe end be inserted into a coupling so that the coupling and pipe end engage properly.

The mechanical coupling, which may be a fitting such as an elbow, tee or straight fitting, for example, includes a housing having a socket coaxially aligned with a receptacle for receiving the pipe end. A sealing member, such as an O-ring or a pressure responsive seal and a retainer are captured within the receptacle adjacent to the socket. The retainer may have a plurality of flexible teeth that extend around the circumference of the receptacle. The teeth project radially inwardly and are angularly oriented toward the socket. When the pipe end is inserted through the receptacle and into the socket, the teeth engage the pipe's outer surface and retain it within the coupling. Due to their angular orientation, the teeth are “self jamming” and resist motion of the pipe that would tend to force it from the receptacle. The sealing member within the receptacle engages the pipe and the housing to provide a fluid-tight seal, and the socket supports the pipe and provides bending stiffness to the joint, preventing angular deflection between the pipe and the coupling.

To ensure an effective, fluid-tight joint, the pipe end must be properly seated within the coupling so that it engages the socket over a sufficient length to insure that the full stiffness of the joint is achieved and so that the sealing member and the pipe outer surface engage and seal relatively to one another. Furthermore, the teeth of the retainer must engage the pipe end to ensure that it is retained within the coupling against the fluid pressure it will eventually see. However, without a visible means to indicate proper engagement of the pipe end with the mechanical coupling it is difficult to be sure that the joint formed will be fluid tight and sufficiently inserted to maximize bending stiffness and strength of the joint. Visible indicators may take the form of “witness marks”, typically circumferential grooves or other visible markings that extend around the pipe in spaced relation to the end. The witness mark is positioned, for example, such that if it is not positioned visible and flush next to the coupling, then the pipe end is not properly engaged with the coupling and must be further inserted until the witness mark is visibly flush with the coupling. It is advantageous to provide a device that will prepare pipe ends for joining with mechanical couplings, for example, by forming one or more witness marks in proper spaced relation to an end of a pipe for a particular coupling and diameter pipe.

SUMMARY OF THE INVENTION

The invention concerns a device for preparing ends of pipes for joining the pipes to one another end to end, preferably although not exclusively using mechanical couplings. The device comprises a body having a receptacle therein sized to receive the end of one of the pipes. One or more tools are mounted on the body and are positioned so as to engage the pipe upon insertion of the pipe within the receptacle. The tools may comprise, for example, a marking tool mounted on the body. The marking tool has a contact surface engageable with the pipe for creating a witness mark, for example, a circumferential groove around the pipe upon rotation of the body and the pipe relatively to one another. A second marking tool may also be mounted on the body. The second marking tool is preferably offset from the first marking tool in a direction lengthwise along the pipe. The second marking tool has a second contact surface positioned so as to engage the pipe upon insertion of the pipe within the receptacle. Together, the first and second marking tools create first and second witness marks on the pipe upon rotation of the body and the pipe relatively to one another.

In addition to or instead of the marking tools, a cutting blade may be mounted on the body. The cutting blade has a cutting edge that extends into the receptacle and is positioned to engage the end of the pipe received therein. The cutting edge is oriented relatively to the pipe so as to create a chamfer on its end upon rotation of the body and the pipe relatively to one another.

The device may also include additional receptacles positioned within the body. The additional receptacles are sized to receive the end of one of the pipes and also have one or more tools mounted and positioned so as to engage the pipe upon its insertion within the additional receptacles. The tools associated with the receptacles may also be marking tools and cutting blades substantially as described above for the first receptacle. Preferably, when two receptacles are present, the first and second receptacles are substantially coaxially aligned with one another and are sized to receive pipes of different diameters. Furthermore, an elongated shaft may be mounted on the body. Preferably, such a shaft has a polygonal cross-section (preferably hexagonal). When mounted, the shaft is oriented substantially coaxially with the receptacles and is engageable with a chuck or a compatible extension shaft such as used with a rachet wrench, power drill or other powered device. The presence of the shaft allows the body to be rotated relatively to the pipe upon rotation of the shaft by the drill or other powered device. Preferably, the shaft extends substantially coaxially through both the first and the second receptacles allowing the body to be turned from either end.

The device may also accommodate a separate marking tool for placing a witness mark on ends of pipes. The device preferably comprises a body having a receptacle therein sized to receive the end of one of the pipes, and an aperture extending through the body and into the receptacle. The aperture is adapted to receive the marking tool, which could be a writing implement such as a pen, pencil or marker or a stylus with a hardened tip for scoring the pipe surface. The marking tool is insertable through the aperture and into the receptacle for the pipe end received therein. The marking tool is adapted to create a witness mark on the pipe upon rotation of the body and the pipe relatively to one another.

DETAILED DESCRIPTION OF THE EMBODIMENTS

FIG. 1shows pipe preparation device10according to the invention. Device10comprises a body12having receptacles14and16at opposite ends. Preferably, receptacles14and16are coaxially aligned with one another and are sized to receive pipes18and20, shown inFIG. 1A, the pipes preferably having different diameters from one another. As body12must be turned relatively to the pipes18and20to effect their preparation, it is convenient to provide radially projecting ribs22to facilitate manual grasping and rotating of the device10. Body12is preferably formed from durable polymer resin to provide a light-weight, inexpensive and robust item that can withstand rough use.

FIG. 2provides an exploded view that illustrates the various tools mounted on the body12that engage the pipe during its preparation. A cutting blade24is mounted on a ledge26formed adjacent to an aperture28that opens into receptacle14. As best shown inFIG. 3, the blade24has a cutting edge30that extends into the receptacle14to engage the end of pipe18inserted into the receptacle. Cutting edge30is oriented or shaped so that it cuts a chamfer32on the end of pipe18when the pipe and body are rotated relatively to one another. It is also contemplated that the cutting edge30may be used so as to form a radius or other shape on the pipe end. Shavings from the pipe are discharged from aperture28. Chamfering the pipe end removes burrs or other irregularities caused by cutting of the pipe stock and also provides a lead-in that facilitates insertion of the pipe end into a coupling. Chamfering reduces insertion force required to deflect typical retainers and seals and also prevents or reduces the potential for damage to the seals. To ensure a proper chamfer, the cutting edge30is positioned so as to engage the pipe18at its center line as illustrated inFIG. 5. Preferably, the cutting blade24is removably mounted on ledge26using a fastener34, allowing the blade to be readily replaced when it becomes dull. Preferably, cutting blade24has multiple cutting edges30. This feature permits another cutting edge30to be indexed into the cutting position extending through aperture28as one edge becomes dull without replacing the blade24, the blade merely being removed, rotated and secured back into position using fastener34. As shown inFIGS. 3 and 6, a second cutting blade36is positioned on a second ledge38positioned adjacent to a second aperture40that opens into the other receptacle16. The second cutting blade36forms a chamfer32on pipe20(seeFIG. 1A) when this pipe is engaged within receptacle16. Again, the cutting blade36is removably mounted using a fastener42and positioned to engage a pipe inserted into receptacle16along the pipe center line.

As further shown inFIG. 2, a plurality of marking tools43are mounted on the body12. Marking tools43are adapted to form witness marks on the pipes and preferably take the form of scoring tools44a,44b,46aand46b. Each scoring tool is received within a respective opening48a,48b,50aand50b, the openings extending into one of the two receptacles14and16as shown inFIG. 4to position two scoring tools within each receptacle. Preferably, each scoring tool includes a threaded cylinder52, the openings48a,48b,50aand50bbeing tapped with compatible threads to allow the scoring tools to be removed and replaced.

Each scoring tool has a contact surface54preferably comprising the surface of a ball56that is positioned at the end of each cylinder52. Springs58within each cylinder52bias balls56so that they project outwardly from each cylinder and into the receptacle in which the scoring tool is mounted. Preferably, the balls are captured within the cylinders, for example by staking.

As best illustrated for receptacle14inFIG. 4, the scoring tools44aand44bare offset from one another by a distance60in a direction lengthwise along pipe18. Thus, when the pipe18is inserted within receptacle14, and the body12and pipe18are rotated in opposite directions relatively to one another, the balls56in each scoring tool44aand44bengage the pipe18and form circumferential grooves62and64(see alsoFIG. 1A). The grooves are offset from one another as determined by the offset distance60. Scoring tools46aand46bin receptacle16are also offset and will form offset grooves66and68around pipe20as shown inFIG. 1Awhen it is engaged within receptacle16. Balls56are preferably made of stainless steel to prevent corrosion and may be hardened as required so that they effectively cold-work the pipe material to form the grooves.

FIGS. 1,5A and6A illustrate an alternate marking tool45that is not mounted on the body12. Instead, body12has an aperture47adapted to receive marking tool45, the tool being insertable through the aperture and into the receptacle16. Upon insertion, as shown inFIG. 5Aor6A, marking tool45is engageable with a pipe32and will form a witness mark on the pipe when the pipe and the body are rotated relatively to one another.

The marking tool45may comprise, for example, a writing implement, such as a pen, a pencil, a marker or other item that will place a line or other indicia on the surface of the pipe32. Tool45may also comprise a stylus with a tip49adapted to score the surface of the pipe32and form a circumferential groove therein. The tip may be, for example, a diamond, a hardened ball, a blade, or other item that will score the surface of the pipe to form a groove. As shown inFIGS. 5A and 6A, apertures47may be positioned in each end of body12so that each receptacle14and16may be used with a marking tool45to form witness marks.

As shown inFIGS. 2 and 4, it is advantageous to position a shaft70coaxially within receptacles14and16to facilitate rotation of the body12when preparing pipes. Shaft70is held in position by metal split pins72and74that extend through holes76and78in body12. Holes76and78align with holes80and82in the shaft70when the shaft is properly positioned within the body12. As shown inFIG. 4, split pins72and74extend into receptacles14and16and act as stops that engage the pipes (as illustrated by pipe14) and prevent them from gouging the body12within the receptacles. Shaft70preferably projects into both receptacles14and16to allow a power drill84(shown in broken line) to be applied to either end of the device to spin the body12when preparing a pipe. Preferably, the shaft70has a polygonal cross sectional shape, such as a hexagon. The polygonal shape allows the shaft70to be engaged by an adapter71that can be turned by a drill84(seeFIG. 4) or other tool such as a rachet wrench. Alternately, as shown inFIG. 7, shaft70may extend outwardly from one or both of the receptacles14and16of body12to directly engage the drill84or other tool that turns it.

As illustrated inFIG. 1A, pipes18and20, having different diameters, may be prepared using device10. Preferably, each of the pipes has two grooves that function as witness marks (62and64for pipe18, and66and68for pipe20) that indicate when a pipe is properly engaged with a pipe coupling. When properly engaged, one of the grooves (64,68) is not visible, it being positioned within the coupling, and the other groove (62,66) is visible adjacent to the end of the coupling providing an indication that the pipe was marked. It is advantageous to be able to ascertain that the pipe was marked so that proper engagement of pipe and coupling can be visually verified. The chamfer32at the ends of the pipes provides a lead-in to facilitate entry of the pipe into the coupling.

The pipe preparation device according to the invention provides a versatile item useful for preparing pipes for engagement with mechanical pipe couplings, the device being usable on more than one diameter pipe.