NZ759847B2 - Cam grooving - Google Patents

Abstract

method for forming a groove in a pipe element. The pipe element is inserted between a plurality of cams. Each cam has a cam surface (160, 162) with a region of increasing radius (164) extending around a cam body. Each cam has a fixed axis of rotation relative to the pipe element. Each cam also has a traction surface extending around a cam body. The pipe element is simultaneously contacted by the plurality of cam surfaces at a plurality of locations on the pipe element. The pipe element is rotated, thereby simultaneously rotating the cam surfaces. Each cam surface engages the pipe element with its increasing radius and thereby deforms the pipe element to form the groove. a traction surface extending around a cam body. The pipe element is simultaneously contacted by the plurality of cam surfaces at a plurality of locations on the pipe element. The pipe element is rotated, thereby simultaneously rotating the cam surfaces. Each cam surface engages the pipe element with its increasing radius and thereby deforms the pipe element to form the groove.

Description

CAM GROOVING CROSS NCE TO RELATED APPLICATIONS This ation is based upon and claims benefit of priority to US Provisional Application No. 62,260,922, filed November 30, 2015; US Provisional Application No. 62/359,395, filed July 7, 2016; US Provisional Application No. 62/363,892, filed July 19, 2016; and US Provisional Application No. 62/395,747, filed September 16, 2016, all of which are hereby incorporated by reference. This is a onal application of New Zealand Patent Application No. 753655, which is a divisional of New Zealand Patent Application No. 740454 the entire contents of each being incorporated herein by reference.

FIELD This invention relates to methods and machines using cams to cold work pipe elements.

BACKGROUND Cold working of pipe elements, for example, impressing a circumferential groove in a pipe element to accept a mechanical pipe coupling, is advantageously accomplished using roll grooving machines having an inner roller which engages an inside surface of the pipe element and an outer roller which simultaneously engages an outside surface of the pipe t te to the inner . As the pipe is rotated about its longitudinal axis, often by driving the inner roller, the outer roller is progressively forced toward the inner roller. The rollers have surface es which are impressed onto the pipe element circumference as it rotates, thereby forming a circumferential groove.

There are various nges which this technique faces if it is to cold work pipe ts with the required tolerances to the necessary precision. Most pressing are the difficulties associated with producing a groove of the desired radius (measured from the center of the pipe element bore to the floor of the ) within a d tolerance range. These considerations have resulted in complicated prior art devices which, for example, require actuators for forcing the rollers into engagement with the pipe element and the ability for the operator to adjust the roller travel to achieve the desired groove radius. Additionally, prior art roll grooving machines 22719152_1:hxa have low production rates, often requiring many revolutions of the pipe element to achieve a finished ferential groove. There is clearly a need for devices, for example, those using cams, to cold work pipe elements which are simple yet produce results with less operator involvement.

SUMMARY The invention concerns a cam for cold working a pipe element. In one example embodiment the cam comprises a cam body having an axis of rotation. A cam surface extends around the cam body. The cam surface comprises a region of increasing radius and a discontinuity of the cam surface. The cam surface may also comprise a region of constant radius positioned adjacent to the tinuity. The radii are measured about and from the axis of rotation. A traction surface extends around the cam body. T he traction surface comprises a plurality of projections ing transversely to the axis of rotation. T he traction surface has a gap therein. T he gap is aligned axially with the discontinuity of the cam surface. In one example embodiment the traction surface overlies the cam surface. In another e ment the traction surface is positioned on the cam body in spaced on to the cam surface. By way of example the cam further comprises a gear d on the cam body coaxially with the axis of on. In one example embodiment the cam surface is positioned between the gear and the on surface. Further by way of example the cam surface is positioned proximate to the traction surface.

In an e embodiment the traction surface has a constant radius measured about and from the axis of rotation.

In a further example embodiment the cam comprises a cam body having an axis of rotation. A ity of cam surfaces extend around the cam body. E ach cam surface comprises a respective region of increasing radius. Each cam surface may also comprise a respective region of constant radius. The radii are measured from and about the axis of rotation. A ll of the cam surfaces are circumferentially aligned with one another. R espective discontinuities of the cam surfaces are oned between each of the cam es.

In an example embodiment the cams further comprise a plurality of traction surfaces extending around the cam body. E ach traction surface comprises a plurality of tions 22719152_1:hxa extending transversely to the axis of rotation. A respective gap in the traction surfaces is positioned between each of the traction surfaces. E ach gap is aligned axially with a respective discontinuity of the cam surface. In an example embodiment, all of the traction es are circumferentially aligned with one another. In a particular example, the traction surfaces overlie the cam surfaces. In another example, the traction surfaces are oned on the cam body in spaced relation to the cam surfaces.

By way of e, a cam further comprises a gear mounted on the cam body coaxially with the axis of rotation. In a specific example the cam surfaces are positioned between the gear and the traction surfaces. In another example the cam surfaces are positioned proximate to the traction surfaces. A specific example embodiment comprises at most two of the cam es and two of the discontinuities of the cam surfaces. Another example embodiment ses at most two of the cam surfaces, two of the discontinuities of the cam surfaces, two of the traction surfaces and two of the gaps in the on surfaces.

The invention further encompasses a device for cold working a pipe element. In one example embodiment the device comprises a housing. A plurality of gears are d within the housing. Each one of the gears is rotatable about a respective one of a plurality of axes of rotation. T he axes of rotation are parallel to one r. T he gears are positioned about a central space for receiving the pipe element. A plurality of cam bodies are each mounted on a respective one of the gears. Each one of a plurality of cam surfaces extend around a respective one of the cam bodies and are engageable with the pipe element received within the central space. E ach one of the cam surfaces comprises a region of increasing radius and a discontinuity of the cam surface. Each one of the cam surfaces may also comprise a region of constant radius positioned adjacent to the discontinuity. Each one of the radii is measured about and from a respective one of the axes of rotation. A t least one traction surface extends around one of the cam . T he at least one traction surface comprises a plurality of projections extending transversely to the axis of rotation of the one cam body. T he at least one on surface has a gap therein. T he gap is aligned axially with the discontinuity of one the cam surface surrounding the one cam body. A pinion is mounted within the central space within the g. T he pinion meshes with the plurality of gears and is rotatable about a pinion axis oriented parallel to the axes of rotation. 22719152_1:hxa r e embodiment comprises a plurality of traction surfaces. E ach one of the traction es extends around a respective one of the cam bodies. Each one of the traction es comprises a plurality of projections extending transversely to a respective one of the axes of rotation. Each one of the traction surfaces has a gap therein. Each gap is aligned axially with a respective one of the discontinuities of one of the cam surfaces on each one of the cam bodies.

In an example embodiment the at least one traction surface overlies one of the cam surfaces. In another example embodiment the at least one traction surface is positioned on the one cam body in spaced relation to the cam surface extending around the one cam body. By way of example a device may se at most, three gears. E ach gear comprises one of the cam bodies and the cam surfaces. Another example embodiment may comprise at most, two gears.

Each gear comprises one of the cam bodies and the cam surfaces.

In an example embodiment, the one cam e is positioned between the gear and the at least one traction surface of the one cam body. by way of further example, the one cam surface is positioned proximate to the at least one traction surface of the one cam body.

An example device may further comprise at least one projection attached to the pinion.

The at least one projection extends transversely to the pinion axis. A t least one cut-out is defined by the housing. T he at least one cut-out is positioned in facing relation with the projection. T he pinion is movable relatively to the housing along the pinion axis between a first position, wherein the tion engages the cut-out thereby preventing rotation of the , and a second on, wherein the projection is out of engagement with the cut-out thereby permitting on of the pinion. In an example embodiment a spring acts n the pinion and the housing to bias the pinion into the first position.

An example embodiment further comprises a cup abutting the pinion. T he cup receives the pipe element upon insertion of the pipe element into the l space. In one e embodiment the cup may be attached to the pinion.

By way of further example, a first finger extends from a first one of the cam bodies in a direction parallel to and offset from a first one of the axes of rotation about which the first one of the cam bodies rotates. A n actuator is y mounted on the housing. T he actuator is 22719152_1:hxa movable into ment with the first finger for ng the first one of the cam bodies about the first one of the axes of rotation. In an example embodiment the actuator comprises a lever pivotably mounted on the housing. T he lever has a first surface able with the first finger for rotating the first one of the cam bodies about the first one of the axes. In a further example the lever has a second surface engageable with the finger for pivoting the lever into a ready position upon rotation of the first one of the cam bodies. In another example a second finger extends from a second one of the cam bodies in a ion parallel to and offset from a second one of the axes of rotation about which the second one of the cam bodies rotates. A stop is movably mounted on the housing. T he stop is movable into engagement with the second finger for preventing rotation of the second one of the cam bodies about the second one of the axes of rotation. U pon movement of the or into engagement with the first finger, the stop further is movable out of engagement with the second finger for permitting rotation of the second one of the cam .

In one e embodiment the stop comprises a hook bly mounted on the housing. The hook has a spur extending therefrom and is engageable with the actuator for rotating the hook out of engagement with the second finger upon movement of the actuator.

An example device further comprises a chuck for receiving the pipe element. The chuck is rotatable about a chuck axis. The chuck axis is ed coaxially with the pinion axis. By way of example the housing is pivotably and slidably mounted adjacent to the chuck. In an example embodiment the device further comprises an electrical motor engaged with the pinion.

In a specific example embodiment the electrical motor comprises a servomotor. T he device further comprises a controller in communication with the otor for controlling the number of rotations of the servomotor and thereby the cam bodies.

Another example embodiment comprises a clutch operating between the electrical motor and the pinion for controlling the number of rotations of the pinion and thereby the cam bodies.

A further example embodiment comprises a crank coupled with the pinion. T he crank permitting manual turning of the pinion and thereby the gears. In a particular example embodiment the crank is directly coupled with the pinion.

The invention further encompasses an e device for cold working a pipe element comprising a housing. A ity of gears are mounted within the housing. E ach one of the 22719152_1:hxa gears is rotatable about a respective one of a plurality of axes of on. T he axes of rotation are parallel to one another. T he gears are positioned about a central space for receiving the pipe element. The e device has a plurality of cam bodies, each cam body is mounted on a respective one of the gears. A plurality of cam surfaces extend around each cam body. E ach cam surface is engageable with the pipe element received within the central space and comprises a region of increasing radius and a region of nt radius. T he radii are measured about and from one of the axes of rotation. A ll of the cam surfaces on each cam body are circumferentially aligned with one another. A respective discontinuity of the cam surfaces is positioned between each of the cam surfaces on each the cam body. A pinion is d within the l space within the housing. T he pinion meshes with the plurality of gears and is rotatable about a pinion axis oriented parallel to the axes of rotation.

Another example embodiment further comprises a plurality of traction surfaces extending around each the cam body. E ach on e comprises a plurality of projections extending transversely to one of the axes of rotation. A respective gap in the traction surfaces is positioned between each of the traction surfaces on each the cam body. E ach gap is aligned axially with a discontinuity of the cam surface. By way of example the cam surfaces are positioned between the gear and the traction surfaces on each cam body. In a specific example embodiment the cam surfaces are positioned proximate to the traction surfaces on each the cam body. In another example embodiment, each of the cam bodies comprises at most two of the cam surfaces and two of the discontinuities. By way of further example each of the cam bodies comprises at most two of the cam surfaces, two of the tinuities of the cam surfaces, two of the traction surfaces and two of the gaps in the traction surfaces.

The invention also encompasses a method of g a groove in a pipe element. In one example embodiment the method comprises: contacting the pipe element with a plurality of cam surfaces simultaneously at a ity of ons on the pipe element; rotating the pipe element, thereby simultaneously rotating the cam surfaces, each cam e engaging the pipe element with an increasing radius and thereby deforming the pipe element to form the groove.

An e embodiment of the method further comprises contacting the pipe element with at least one traction surface mounted on at least one cam comprising one of the cam 22719152_1:hxa surfaces. Another example embodiment comprising contacting the pipe element with a plurality of traction surfaces. In this example one the traction surface is mounted on a tive one of the cams. E ach of the cams comprises one of the plurality of cam surfaces.

Another example embodiment comprises synchronizing rotation of the cam surfaces with one another. A further example embodiment comprises using an or to initiate rotation of one of the cam surfaces.

BRIEF PTION OF THE DRAWINGS Figure 1 is an isometric view of an example ment of a device according to the invention; Figure 2 is an exploded isometric view of a portion of the device shown in Figure 1; Figure 3 is an exploded isometric view of components of the device shown in Figure 1; Figure 4 is an exploded isometric view of components of the device shown in Figure 1; Figure 4A is an end view of an e cam according to the invention; Figure 4B is a side view of an example cam according to the invention; Figure 4C is an ric view of an example cam according to the invention; Figure 5 is a cross sectional view of device 10 taken at line 5-5 of Figure 1; Figures 6 through 9 and 9A are additional cross sectional views illustrating operation of device 10; s 10-12 are cross sectional views illustrating a safe reverse mode of the device 10 when a pipe element is d in the wrong direction; Figure 13 is a partial view of another example embodiment of a device according to the invention; 22719152_1:hxa Figure 14 is an end view of another example cam ing to the invention; Figures 15 and 16 are isometric views of example embodiments of devices ing to the invention; and Figure 17 is an ric view of another example embodiment of a device according to the invention.

DETAILED DESCRIPTION Figure 1 shows an example device 10 for cold working a pipe element, for example, forming a circumferential groove in the pipe t’s outer surface. Device 10 is shown pivotably mounted on a rotating power chuck 12. Such chucks are well known, an example being the Ridgid 300 Power Drive marketed by Ridgid of Elyria, Ohio.

Figure 2 shows an ed view of device 10 which comprises a housing 14. Housing 14 is formed of a g body 16 and a cover 18. A plurality of gears, in this example three gears 20, 22 and 24 are rotatably mounted on respective shafts 26, 28 and 30, the shafts being supported by the housing body 16 and cover 18 and defining respective axes of rotation 32, 34 and 36. Axes 32, 34 and 36 are arranged parallel to one another. In a practical design each gear , 22 and 24 has a respective flanged bushing 38, and may also have a thrust washer 40 and a compression spring 42. The compression springs 42 act between the gears 20, 22 and 24 and the cover 18 to bias the gears away from the cover.

Gears 20, 22 and 24 are positioned about a central space 44 which receives a pipe element 136 to be cold worked by the device 10. An g 46 in cover 18 provides access to the central space 44 and permits pipe element insertion into the device 10. As shown in Figures 2 and 3, a pinion 48 is mounted on housing body 16 within the central space 44. Pinion 48 meshes with gears 20, 22 and 24 and comprises a pinion shaft 50 which defines a pinion axis of rotation 52 oriented parallel to the axes 32, 34 and 36 of the gears 20, 22 and 24. Pinion shaft 50 is supported by a flanged pinion bushing 54 fixedly attached to the housing body 16. In a practical design, a thrust bearing 56 and thrust washers 58 are interposed between the pinion 48 and the housing body 16. 22719152_1:hxa With reference to Figure 3, pinion 48 is movable relatively to housing 14 in a direction along the pinion axis 52. A projection 60, in this example a crossbar 62 is attached to the pinion 48 and extends transversely to the pinion axis 52. A cut-out 64, defined in the housing body 16, is in facing relation with the projection 60 (crossbar 62). In this example, the cut-out 64 is in the pinion bushing 54 which is fixedly attached to and considered to be part of the housing body 16.

Axial motion of the pinion 48 along pinion axis 52 moves the pinion between two positions, a first position wherein the crossbar 62 (projection 60) engages the cut-out 64, and a second position wherein the cross bar 62 is out of engagement with the cut-out 64. When crossbar 62 s the cut-out 64 the pinion 48 is prevented from rotating about the pinion axis 52; when the cross bar 62 does not engage the t 64 the pinion 48 is free to rotate about the pinion axis 52. One or more springs 66 act n the pinion 48 and the housing body 16 to bias the crossbar 62 into the first position in engagement with the cut-out 64. Rotation of the pinion 48 is permitted when a pipe element 136 is inserted through opening 46 into the central space 44 (see Figure 2) and held against the pinion 48 to compress the springs 66 and disengage the crossbar 62 from the cut-out 64. To provide contact between the pinion 48 and the pipe element, a cup 68 abuts the pinion shaft 50 and is captured n the cam bodies. In a cal design the cup 68 may be attached to the pinion or free-wheeling. Cup 68 receives and maintains the pipe element in alignment with the pinion 48 so that it may be turned when cold g the pipe element as described below. Cup 68 also helps limit pipe end flare during cold g.

As shown in Figure 4, device 10 ses a plurality of cams 69, in this example, three cams having respective cam bodies 70, 72 and 74. Each cam body 70, 72 and 74 is mounted on a respective gear 20, 22 and 24. Each cam body 70, 72 and 74 comprises a respective cam surface 76, 78 and 80. Each cam surface 76, 78 and 80 s around their respective cam body 70, 72 and 74. The cam surfaces 76, 78 and 80 are engageable with a pipe t received within the central space 44.

As shown in detail in Figure 4A, each one of the cam surfaces 76, 78, 80 (76 shown) comprises a region 82 of increasing radius 82a and a discontinuity 86. Each one of the cam surfaces may also include a region 84 of nt radius 84a positioned adjacent to the discontinuity 86. The radii 82a and 84a (when present) are measured about and from the respective axes of rotation 32, 34 and 36 of the gears 20, 22 and 24 (shown for the cam surface 76, the axis 32 of gear 20). As shown in Figure 5, the discontinuities 86, when facing the central space, provide nce permitting insertion of the pipe element into the cup 68. With 22719152_1:hxa reference again to Figure 4A, the example device 10 has three cam bodies 70, 72 and 74. T he regions of constant radius 84 extend along an arc length which is at least 1/3 of the circumference of the finished circumferential groove in the pipe element so that the groove may be formed to a uniform radius around the entire circumference of the pipe element during one revolution of each cam body 72, 74 and 76. In an example practical design (see Figure 4A), the region of increasing radius 82 may subtend an angle 88 of approximately 260°, and the region of constant radius (when present) may subtend an angle 90 of approximately 78°, the discontinuity 86 subtending an angle 92 of approximately 22°. For devices 10 having a number of cams other than three and the constraint that the groove be formed to a uniform radius around the entire circumference of the pipe element in one tion of each of the cams, the arc length of the region of constant radius of each cam body is ageously 1/N, where "N" is the number of cams in the design. However, it is feasible to reduce or eliminate entirely the region of constant radius. Elimination of this region will reduce the torque required to form the groove.

As shown in s 4 and 4B, it is advantageous to include at least one traction surface 94 on one of the cam bodies such as 70. In the example device 10 each cam body 70, 72 and 74 has a respective traction surface 94, 96 and 98. T he traction surfaces 94, 96 and 98 extend circumferentially around their respective cam bodies 70, 72 and 74 and have a constant radius measured about and from the respective axes of rotation 32, 34 and 36. The cam surfaces 76, 78, 80, are oned between the gears 20, 22 and 24 and the traction es 94, 96 and 98, the cam surfaces being positioned proximate to the traction surfaces. As shown in Figure 4 B, each traction surface (94 shown) ses a plurality of projections 100 which extend ersely to the respective axes of rotation 32, 34 and 36. Projections 100 provide mechanical engagement and purchase between the cam bodies 70, 72 and 74 and the pipe element which the on surfaces engage. Each traction surface 94, 96 and 98 also has a gap 102. Each gap 102 in each traction e 94, 96 and 98 substantially aligns axially with a respective discontinuity 86 in each cam surface 76, 78, 80 to provide clearance permitting insertion and awal of the pipe element into and from the cup 68. In another cam embodiment 69a, shown in Figure 4C, the traction surface 94 overlies the cam surface 76. The gap 102 in the traction surface 94 is again aligned with the discontinuity 86 in the cam surface 76.

As shown in Figure 5, it is further advantageous to include an actuator 106 to te motion of the cam bodies 70, 72 and 74. In this example embodiment, actuator 106 comprises an actuator lever 108 pivotably d on the housing body 16. Actuator lever 108 has a first 22719152_1:hxa surface 110 which engages a finger 112 on cam body 74 to initiate rotation of the cam body.

Finger 112 is offset from the axis of rotation 36 of cam body 74 and s from cam body 74 in a direction parallel to the axis 36 (see also Figure 2). The offset of finger 112 allows the actuator lever 108, when pivoted about its pivot axis 108a (aligned parallel to the pinion axis 52), to apply a torque to the cam body 74 (gear 24) and rotate it about axis 36. This rotates all of the cam bodies 70, 72 and 74 because their respective gears 20, 22 and 24 mesh with the pinion 48, thus the act of turning any one gear or turning the pinion turns all gears. Actuator lever 108 also has a second surface 114 which is engaged by the finger 112 as the cam body 74 rotates. The second surface 114 is curved in this example and allows the rotating cam body 74 to reset the relative positions of the finger 112 and the actuator lever 108 so that upon one rotation of the cam body 74 the actuator lever 108 is pivoted to a "ready" position as shown in Figure 6, ready to apply a torque to the cam body and initiate rotation.

It is further advantageous to include a stop 116, y mounted on housing body 16 to prevent motion of the cam bodies. In this example ment, stop 116 comprises a hook 118 pivotably mounted on the housing body 16 with a pivot axis 118a aligned parallel to the pinion axis 52. Hook 118 engages a finger 120 on cam body 70 (gear 20). Finger 120 is offset from the axis of rotation 32 of cam body 70 and extends from cam body 70 in a direction parallel to the axis 32 (see also Figure 2). The offset allows the hook 118 to arrest counter clockwise motion of cam body 70 as bed below. Tangent surfaces 122 and 124 are positioned at the end of hook 118 for engagement with finger 120 during ion of the device as described below. A torsion spring 126 (see also Figure 2) acts between the hook 118 and the housing body 16 to bias the hook in a r clockwise direction around pivot axis 118a. Hook 118 also has a spur 128 which extends to the opposite side of the pivot axis 118a from the hook (see also Figures 2 and 4). Actuator lever 108 has a foot 130 which engages spur 128 to pivot the hook 118 out of engagement with finger 120 upon movement of the actuator lever 108 into engagement with the finger 112, forcing the cam 74 counterclockwise to te motion of the cam bodies 70, 72 and 74 as described below.

Operation of device 10 begins with the cam bodies 70, 72 and 74 aligned as shown in Figure 6 such that the discontinuities 86 in the cam surfaces 76, 78 and 80 (see also Figure 4) and gaps 102 in the traction surfaces 94, 96 and 98 simultaneously face the pinion axis 52. As shown in Figure 1, device 10 is mounted on tubes 132 extending from one end of the rotating chuck 12. T he opening 46 in g cover 18 faces the chuck 12 (see Figure 2). Pinion axis 52 22719152_1:hxa is coaxially aligned with the axis of rotation 134 of chuck 12. A pipe element 136 is inserted into the opposite end of the chuck 12 so that the end of the pipe element extends outwardly from the chuck toward device 10. Chuck 12 is tightened to secure the pipe element and the device 10 is then moved along tubes 132 toward and into engagement with the pipe element.

With reference to Figures 2 and 4, the pipe element passes through opening 46 and into the central space 44. Aligned discontinuities 86 and gaps 102 provide the clearance necessary to permit the pipe element to pass by cam surfaces 76, 78 and 80 and traction surfaces 94, 96 and 98 to be received in the cup 68. The pipe element is thus aligned with the pinion axis 52.

Device 10 is moved r toward chuck 12 (see Figure 1) so as to cause the pinion 48 to move y along the pinion axis 52 and compress springs 66 iently to move the cross bar 62 from the first to the second position out of the cut-out 64 in the pinion bushing 54 (see Figure 9A) to permit rotation of the pinion 48, and consequently rotation of gears 20, 22 and 24 which mesh with it. The chuck 12 is then actuated, which rotates the pipe element clockwise as viewed in Figures 5 and 6. Alternately, rotation of the pipe element can be initiated and then the device can be slid into engagement with the pipe element.

Engagement between the pipe element and the cup 68, when the cup is not fixed to the pinion, may cause the cup to rotate clockwise with the pipe. When the cup 68 is freewheeling ve to the pinion 48, the torque itted via friction between the cup 68 and the pinion 48 may try to rotate the pinion, and consequently gears 20, 22 and 24. M otion of the gears is easily prevented by engagement between the hook 118 and the finger 120 ing from cam body 70 (gear 20). There is furthermore no significant engagement between the pipe element and the cam bodies because the discontinuities 86 in the cam surfaces 76, 78 and 80 (see also Figure 4) and gaps 102 in the traction surfaces 94, 96 and 98 simultaneously face the pinion axis 52 and do not significantly contact the pipe at this time. If the cup 68 is fixedly attached to the pinion 48 then engagement n hook 118 and finger 120 again prevents motion of the gears and pinion, the pipe element merely rotates within the cup.

To initiate gear and cam body rotation, actuator lever 108 is depressed, causing it to pivot counterclockwise about its axis 108a as viewed in Figure 6. As shown in Figure 7, pivoting of actuator lever 108 causes its first surface 110 to engage the finger 112 extending from cam body 74, and also causes the foot 130 to engage the spur 128 of the hook 118. Hook 118 pivots ise about its axis 118a and winds its biasing spring 126 (see also Figure 2). The ry 22719152_1:hxa of the actuator lever 108, hook 118 and its spur 128 is ed such that finger 120 on cam body 70 is released from the hook 118 as torque is applied to rotate cam body 74 via engagement of the first surface 110 of actuator lever 108 with finger 112. Figure 7 shows finger 120 on the verge of release from hook 118 and cam body 74 just before ment with the pipe t.

As shown in Figures 8 and 4, further pivoting of the actuator lever 108 pivots the hook 118 and releases the finger 120 from hook, by permitting motion of the gear 20) while applying torque to the cam body 74 (gear 24) to initiate rotation of the pinion 48 and gears 20, 22 and 24 and their associated cam bodies 70, 72 and 74. The cam bodies rotate counter clockwise and their cam es 76, 78 and 80 and traction surfaces 94, 96 and 98 engage the outer surface of the pipe element. The cam bodies 70, 72 and 74 are then driven by the rotating pipe element.

The regions of increasing radius 82 (see Figure 4A) of the cam surfaces 76, 78 and 80 first engage the pipe element and begin to form a circumferential groove in it as the cam bodies 70, 72 and 74 . The traction es 94, 96 and 98 (see Figure 4B) also engage the pipe element and provide mechanical engagement which prevents slippage between the cam surfaces 76, 78 and 80 and the pipe element. As the radius at the point of contact between the cam surfaces and the pipe element increases, the groove radius is made smaller until the point of contact transitions to the region of constant radius 84 (Figure 4A) of each cam surface 76, 78 and 80. For a device 10 having three cam bodies with respective regions of nt radius, each region of constant radius 84 extends over at least 1/3 of the circumference of the finished circumferential groove in the pipe element. The radius of the region of constant radius is designed to impart the final desired groove radius to the circumferential groove in the pipe element at a uniform radius around the entire circumference of the pipe t with one revolution of all three cam bodies. Alternately, when the regions of constant radius are not present on the cams, the groove radius is not uniform, but form separate partial spirals, one for each cam. Although not uniform, the radius of the groove falls within the necessary tolerances for the ’s intended use.

As shown in Figures 9 and 9A, cam body 74 nears completion of its single revolution and the finger 112 contacts the second (curved) surface 114 of the actuator lever 108. Interaction between finger 112 and surface 114 causes the actuator lever 108 to pivot clockwise about its pivot axis 108a and return to the starting position shown in Figure 6. Hook 118 follows, biased by the spring 126 to pivot counterclockwise into a position ready to receive the finger 120. When ued rotation of cam body 70 occurs it moves finger 120 into hook 118 which stops motion of the gears 20, 22 and 24. It is also feasible to design spring 126 to have sufficient stiffness such 22719152_1:hxa that it will pivot both the hook 118 and the actuator lever 108 back into the start position shown in Figure 6 when the actuator lever is released. Upon completion of groove formation the chuck 12 is stopped and the pipe element, now grooved, may be removed from device 10.

Figures 10-12 illustrate an anomalous condition wherein the pipe t is inadvertently rotated counterclockwise. This may happen due to operator error, as power chucks such as the Ridgid 300 are capable of applying significant torque in both directions.

If reverse torque (i.e., torque which will rotate the pipe element counterclockwise as viewed in Figure 10) is d before the pipe element has been grooved, the pipe element will merely rotate relative to the cam bodies 70, 72 and 74 and their ated gears 20, 22 and 24 because the discontinuities 86 in the cam es 76, 78 and 80 (see also Figure 4) and gaps 102 in the traction surfaces 94, 96 and 98 simultaneously face the pinion axis 52 and thus neither surface contacts the pipe element. Additionally the ends of the discontinuities in the cam surfaces, being at the end of the region of constant radius 84, are too steep for the pipe element to climb through frictional contact even if the pipe element and the cam surfaces come into contact.

Depressing the actuator lever 108 will have no significant effect, as this action will try to rotate the cams and gears in the opposite direction from how the pipe element, rotating under reverse torque, will try to turn the cam bodies via friction between the cup 68 and pinion 48 when the cup is not fixedly ed to the pinion.

However, if reverse torque is inadvertently applied after a pipe element has been grooved, the s of constant radius 84 of the cam surfaces 76, 78 and 80 are at approximately the same radius as the floor of the groove and thus will gain se and rotate the cam bodies 70, 72 and 74 clockwise. The torque on the cam bodies (and their ated gears 20, 22 and 24) will be augmented when the pipe element further contacts the traction surfaces 94, 96 and 98. As significant torque is d to the pipe element, measures are taken to prevent damage to the device 10.

Figures 10-12 illustrate the condition wherein reverse torque is applied to a pipe element which has already been grooved. As shown in Figure 10, the cam bodies 70, 72 and 74 are driven ise. The finger 120 on cam body 70 is moved away from the hook 118, but the finger 112 of cam body 74 is driven against the actuator lever 108. Actuator lever 108 is free to pivot clockwise in response to this applied force, the pivoting motion allowing the finger 112 to 22719152_1:hxa fall off of the first surface 110 of the actuator lever 108 and engage the second (curved) surface 114, thereby avoiding any damage to device 10. As shown in Figure 11, the cam bodies continue to rotate ise and the finger 120 of cam body 70 comes into t with the first of the two tangent surfaces 122 and 124 on the end of hook 118. As shown in Figure 12, the first tangent surface 122 is angularly oriented such that it permits the finger 120 to pivot the hook 118 clockwise against its biasing spring 126 in response to the force applied by the finger 120.

Pivoting motion of the hook 118 further prevents damage to the device 10. As the finger 120 transitions to the second tangent surface 124 the hook 118 is permitted to pivot counterclockwise under the force of its biasing spring 126 and move again to the ready position shown in Figure , as does the finger 112 on cam body 74. This motion will repeat until the motion of the pipe element is stopped.

Figure 13 shows another example embodiment of a device 138 according to the invention having at most two gears 140, 142. Gears 140, 142 are mounted within a g 144 for on about respective axes 146, 148. Axes 146, 148 are oriented parallel to one another. A pinion 150 is mounted on g 144 within a central space 152 which receives a pipe element for processing. Pinion 150 meshes with gears 140, 142 and rotates about a pinion axis 154 oriented parallel to axes 146 and 148.

Cam bodies 156, 158 are respectively mounted on gears 140, 142. As shown in Figure 14, each cam body (156 shown) ses a plurality of cam surfaces, in this example, two cam surfaces 160 and 162. Other cam embodiments, including cams having a single cam surface or cams having more than two cam surfaces are also feasible. The cam surfaces 160 and 162 extend around the respective cam bodies 156 and 158 and are engageable with the pipe element received within the central space 152. The cam surfaces 160 ad 162 are circumferentially aligned with one another. Each cam surface 160, 162 comprises a respective region of increasing radius 164 and a region of nt radius 166. The radii are respectively measured about and from the axes of rotation 146 and 148. Respective tinuities 168, 170 are positioned between each cam surface 160, 162 on each cam body 156, 158.

As further shown in Figure 14, a plurality of on surfaces, in this example two traction surfaces 172, 174, extend around each cam body 156, 158 (156 shown). Traction surfaces 172, 174 are circumferentially d with one another in this example. Traction surfaces 172, 174 each comprise a plurality of tions 176 which extend transversely to 22719152_1:hxa respective axes of rotation 146, 148. tive gaps 178, 180 are oned between each traction surface 172, 174 on each cam body 156, 158. Gaps 178, 180 are respectively aligned with discontinuities 168, 170 in the cam surfaces 160, 162. As in the earlier discussed embodiment, the cam surfaces 160, 162 on each cam body 156, 158 may be positioned, between the respective gears 140, 142 and the traction surfaces 172, 174, and the cam surfaces may be located proximate to the traction surfaces on each cam body.

Cams having a plurality of cam surfaces and traction surfaces are sized so that they form a complete circumferential groove for a fraction of a rotation. For example, cams 182 as illustrated in Figures 13 and 14 having at most two cam surfaces and two traction surfaces form a complete circumferential groove in one half a revolution of the cams.

Although devices having 2 and three cams are illustrated herein, designs having more than three cams are advantageous for forming grooves having a consistent radius, especially in pipe elements having a nominal pipe size of 2 inches or r, or for pipe ts of any size having a variety of wall thicknesses.

Figure 15 shows another embodiment 184 of a device for cold working pipes.

Embodiment 184 comprises a g 14 in which cams 69 (shown) or cams 182 are rotatably mounted and mesh with a pinion 48. In this embodiment an electrical motor 186 is coupled to the pinion, either directly or through a gear box. In this arrangement it is advantageous if the electrical motor 186 is a servomotor. A servomotor allows for precise control of the number of tions of the cams 69 so that the discontinuities in the cam surfaces and the gaps in the on surfaces are aligned at the beginning and end of the grooving procedure so that the pipe element can be inserted and removed easily. Control of the otor is effected using a programmable logic controller 188 or other similar rocessor based computer.

Figure 16 illustrates another device embodiment 190 wherein a clutch 192 operates between the electrical motor 186 and the pinion 48. In this example, motor 186 is coupled to the clutch 192 through a reduction gear 194. The clutch 192 engages the pinion 48 through a link chain shaft coupling 196 which sates for misalignment between the clutch and the pinion. Clutch 192 is a wrapped spring type, examples of which are commercially ble from Inertia Dynamics of New Hartford, CT. Wrapped spring clutches are readily adjustable to engage and disengage tically as needed to produce a desired number of revolutions of 22719152_1:hxa pinion 48 to achieve a number of revolutions of the cams 69 required to form a circumferential groove and have the discontinuities of the cam surfaces and gaps in the traction es facing the pinion at the end of the grooving process.

Figure 17 illustrates another example device embodiment 198 wherein the device is supported directly on the pipe element 136 being cold worked. Pipe element 136 is, in turn, supported on a pipe vise 200 or other ient t means which will prevent the pipe element from turning when torque is d about its axis 202. Device 198 is substantially similar to device 10 described above, but has a crank 204 coupled with the pinion 48 for manually turning the pinion, and thereby gears 20, 22 and 24 and their associated cam bodies 70, 72, 74, cam surfaces 76, 78, 80 and traction surfaces 94, 96, 98 (see also Figure 2) to form a groove of uniform radius over the entire circumference of the pipe element 136. Crank 204 may be d to the pinion 48 by directly engaging the pinion shaft 52 (a t" coupling between the crank and the pinion), or a gear train (not shown) may be interposed between the crank and the pinion shaft to reduce the torque required for manual operation.

In operation (see Figures 2 and 17) the pipe element 136 is affixed to the pipe vise 200 and the opening 46 in the cover 18 of the housing 14 is d with the pipe axis 202. The opening 46 is then engaged with the pipe element 136 and the housing 14 is slid onto the pipe element, which enters the central space 44 and is received within the cup 68 to seat the end of the pipe element 136 to the proper depth within the device 198 so that the groove is formed at the desired distance from the end of the pipe element. ally, to ensure proper pipe element seating, device 198 may be equipped with the axially e pinion 48 as bed above.

When this feature is present the housing 14 is further forced toward the pipe element to move the pinion 48 axially and disengage the cross bar 62 from the cut-out 64 to permit the pinion to rotate relatively to the housing 14, thus ensuring proper seating of the pipe element 136 within device 198. Turning of the crank 204 will then turn the pinion 48, which will turn the cams 69 through the gears 20, 22 and 24 g with the pinion 48. Rotation of the gears engages the cam surfaces 76, 78 and 80 and the traction surfaces 94, 96 and 98 with the pipe element and the device 198 rotates about the pipe element 136 to form a circumferential groove of uniform radius. Upon one rotation of the cams 69 the groove is complete, and this condition is signaled to the operator by an abrupt decrease in the torque required to turn the crank 204. With the gaps 102 in the traction surfaces and the discontinuities 86 in the cam surfaces facing the pipe element 22719152_1:hxa 136, nce is provided and the device 198 may be removed from the pipe element. T he d pipe element may then be removed from the vise 200.

Devices according to the invention are expected to operate effectively and cold work pipe elements to the desired dimensional tolerances with precision while operating more quickly and simply without the need for operator intervention. 22719152_1:hxa I/WE

Claims (5)

CLAIM 1.:

1. A method of forming a groove in a pipe element, said method sing: inserting said pipe element between a plurality of cams, each said cam having a fixed axis of rotation relatively to said pipe t, each said cam having a cam surface comprising a region of increasing radius; contacting said pipe element with a plurality of said cam surfaces aneously at a plurality of ons on said pipe element; ng said pipe element, thereby simultaneously rotating said cam surfaces, each said cam surface engaging said pipe element with said increasing radius and thereby deforming said pipe element to form said groove.

2. The method according to claim 1, further comprising contacting said pipe element with at least one traction surface mounted on at least one cam comprising one of said cam surfaces.

3. The method according to claim 1, further comprising ting said pipe element with a plurality of traction surfaces, one said on surface mounted on a respective one of a plurality of cams, each of said cams comprising one of said plurality of cam surfaces.

4. The method according to any one of the preceding claims, further comprising synchronizing rotation of said cam surfaces with one another.

5. The method according to any one of the preceding claims, further comprising using an actuator to initiate rotation of one of said cam surfaces. Victaulic Company By the Attorneys for the Applicant SPRUSON & ON Per: 22719152_1:hxa