CA1088918A - Power tong drive mechanism - Google Patents
Power tong drive mechanismInfo
- Publication number
- CA1088918A CA1088918A CA298,657A CA298657A CA1088918A CA 1088918 A CA1088918 A CA 1088918A CA 298657 A CA298657 A CA 298657A CA 1088918 A CA1088918 A CA 1088918A
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- CA
- Canada
- Prior art keywords
- pipe
- partial ring
- ring
- gear
- pinion
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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Abstract
ABSTRACT
A power tong includes a frame and a pipe-gripping mechanism associated with a throat at one end of the frame.
Power is transmitted to the pipe-gripping mechanism from a power unit comprising a multiple speed motor through a drive train.
The pipe-gripping mechanism cooperates with the throat to receive a pipe section to be rotated and includes a partial ring rotatably mounted within the frame and having an opening which may be aligned with the throat. The ring may be rotated in either direction by the power unit. Mounted on the tong is a die carrier which is rotatable relative to the ring. Link members are pivotally mounted on the die carrier and include dies positioned to grip the external surface of the pipe section.
The link members are arranged to cooperate with specially designed cam surfaces on the ring so that, when the ring is rotated relative to the die carrier, the dies moved into engagement with the pipe section. After the movable dies have engaged the pipe section further relative movement between the ring and the die carrier is prevented and the pipe section is therefore rotated to make up or break apart the threaded joint of the pipe.
The drive mechanism comprises a multiple speed motor capable of rotating the partial ring in either direction. The motor includes a gear shaft which drives a pinion gear. A pair of pinion idler gears are positioned on either side of the pinion gear and are rotated thereby. A pair of rotary idler gears are driven by the pinion idler gears, and the rotary idler gears each drive a rotary gear associated with the partial ring.
A power tong includes a frame and a pipe-gripping mechanism associated with a throat at one end of the frame.
Power is transmitted to the pipe-gripping mechanism from a power unit comprising a multiple speed motor through a drive train.
The pipe-gripping mechanism cooperates with the throat to receive a pipe section to be rotated and includes a partial ring rotatably mounted within the frame and having an opening which may be aligned with the throat. The ring may be rotated in either direction by the power unit. Mounted on the tong is a die carrier which is rotatable relative to the ring. Link members are pivotally mounted on the die carrier and include dies positioned to grip the external surface of the pipe section.
The link members are arranged to cooperate with specially designed cam surfaces on the ring so that, when the ring is rotated relative to the die carrier, the dies moved into engagement with the pipe section. After the movable dies have engaged the pipe section further relative movement between the ring and the die carrier is prevented and the pipe section is therefore rotated to make up or break apart the threaded joint of the pipe.
The drive mechanism comprises a multiple speed motor capable of rotating the partial ring in either direction. The motor includes a gear shaft which drives a pinion gear. A pair of pinion idler gears are positioned on either side of the pinion gear and are rotated thereby. A pair of rotary idler gears are driven by the pinion idler gears, and the rotary idler gears each drive a rotary gear associated with the partial ring.
Description
The present invention relates to power tongs of the type commonly used in oil fields for making up and breaking apart threaded connections between drill pipes, casing, tubing, and the like. More particularly, the present invention relates to an improved drive mechanism for a power tong assembly such as described in Canadian patent application No. 256,117, filed June 30, 1976.
It is frequently necessary in oil field operations to connect or disconnect joints of pipe which are threadedly connected together. Strings of drill pipes, for example, comprise a series of pipe sections joined together at their ends. Power tongs are employed for making up and breaking apart these connections and are used to rotate the pipes relative to each other. A typical power tong includes a mechanism for gripping the external surface of a pipe section and then rotating the pipe section while the pipe section to which it is connected is held stationary or rotated in the opposite direction.
A variety of power tong constructions have been developed for accomplishing this result. U.S. Patent No.
It is frequently necessary in oil field operations to connect or disconnect joints of pipe which are threadedly connected together. Strings of drill pipes, for example, comprise a series of pipe sections joined together at their ends. Power tongs are employed for making up and breaking apart these connections and are used to rotate the pipes relative to each other. A typical power tong includes a mechanism for gripping the external surface of a pipe section and then rotating the pipe section while the pipe section to which it is connected is held stationary or rotated in the opposite direction.
A variety of power tong constructions have been developed for accomplishing this result. U.S. Patent No.
2,879,680 to Beeman et al, which is commonly assigned with the present application, is illustrative of one type of tong construction. Although devices of this type have proved satisfactory for most oil field operations, extensive use and experimentation has shown that improvements are needed, particu-larly with respect to the pipe-gripping mechanism and the means for urging the mechanism into contact with the pipe.
An improved pipe-gripping mechanism and means for urging the mechanism into contact with the pipe is described in the above-identified patent application. In that application, the power unit for transmitting power to the pipe-gripping mechanism comprises a single speed motor having a gear train :~ i . .. . .
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which transforms the single rotational speed of the motor sha~t into two speed movement of the partial ring. The gear train includes a motor drive gear meshing with a clutch assembly including a low-speed clutch gear and a high speed clutch gear which is selectively actuated by moving a shifting collar which surrounds the clutch shaft by a conventional shifting assembly.
The low and high speed clutch gears mesh with low and high speed pinnon gears which are carried by a sleeve. The sleeve includes gear teeth which mesh pinion idler gears, which in turn drive rotary idler gears which mesh with gear teeth on the partial ring. Such a power unit has a number of undesirable features.
It is required that the gears be-manually shifted in order to provide the desired speed and torque requirements to rotate the partial ring. Since such clutch assel~lies required for shifting do not include a synchromesh arrangement, which would be too costly, problems in aligning the gears to mesh perfectly without damage to the gears frequently occurs. Further, the increased cost associated with multiple gears and clutch assemblies has proved undesirable and less efficient than the present invention.
Accordingly, an object of the present invention is to provide a power tong for making up and taking apart joints of drill pipe, casing, tubing, and the like having an improved drive assembly.
Another object of the invention is to provide a power tong having an improved drive assembly comprising a multiple speed motor, preferably a two speed motor and a drive train that eliminates shifting and reduces the number of moving parts.
It is still further an object of this invention to provide a multiple speed hydraulic or pneumatic motor having two speed ranges and two torque ranges that is coupled directly ~O~B918 through a single series of gears to rotate the partial ring, thus urging the pipe-gripping mechanism into contact with the pipe to be rotated.
Accordi~g to the invention, an improved power tong for rotating a pipe comprises a frame having a throat for re-ceiving a pipe, a partial ring rotatably mounted on said frame and having an opening therein which is adapted to be aligned with said throat so that a pipe may be positioned within said partial ring, said partial ring defining cam surfaces having a cam angle of about 1/2 to 5-1/2 degrees positioned on opposite sides of the center line of said opening, means for rotating said partial ring about its central axis, die means operatively associated with said partial ring, said die means including dies positioned on opposite sides of said center line of said opening, rotation of said partial ring causing said cam surfaces to move said die means inwardly so that said dies grip the pipe on opposite sides thereof for turning movement of said pipe, and said means for rotating said partial ring comprising a vari-able speed motor mounted on said frame, and a drive train compri-sing a plurality of gears coupling said motor to said partial ring.
In the preferred embodiment, the partial ring may be rotated in either the clockwise or counterclockwise direction by the power unit and drive train which cooperates with gear teeth rigidly fixed to the ring.
The power unit and drive train preferably comprises a multiple speed hydraulic or pneumatic motor, preferably a two-speed motor, that has two speed ranges and two torque ranges.
The motor is mounted on the rearward portion of the tong assembly -and comprises a drive shaft with a gear mounted thereon. A
~ _4_ ... ,~ :
.: ; , 1~)i5 ~39~8 pinion gear assembly meshes with the drive gear of the motor and is rotated in either direction at either speed or torque range.
A pair of pinion idler gears mesh with the pinion gear and in turn drive rotary idler gears which are positioned adjacent a rotary gear mounted on the parital r:ing. The rotary gear rota-tion drives the partial ring in a desired direction for moving the pipe mechanism into -4a-~88~L8 engagement with the pipe to be rotated.
A die carrier is mounted on the tong and is rotatable relative to the ring. The die carr:ier includes link members which are pivotally mounted on the carrier and have dies positioned to grip the external surface of the pipe section which is to be rotated. The link members are arranged to cooperate with specially designed cam surfaces on the ring so that, when the ring is rotated relative to the die carrier, the dies are moved into engagement with the pipe section. After the movable dies have engaged the pipe section, further relative movement between the ring and the die carrier is prevented and the pipe section is therefore rotated to make up or break apart a threaded joint of pipe.
Figure 1 is a plan view of the front portion of a power tong according to the invention;
Figure 2 is a plan view of the entire power tong of Figure 1 with the top plate of the frame, the door and the die carrier removed;
Figure 3 is a vertical cross section view taken along ~ -20 the lines 3-3 in Figure 2 to show the rotary gear-rotary idler arrangement; and J Figure 4 is a vertical cross section view taken along the line 4-4 in Figure 2 to show the motor drive, pinion gear, and pinion idler arrangement.
Referring now in detail to the drawings, the frame 2 of the power tong includes an upper plate 4 and a lower plate 5 spaced apart and bolted to the sidewalls 7. The frame 2 has an arcuate front portion defining a throat 10 for receiving a pipe section such as a section of drill pipe, casing, tubing 30 or the like.
Pivotally mounted to the frame 2 adjacent the throat :' ' :' ' , ' . ',, . , 10 by means of a hinge pin 24 is a door 26 which may be opened by means of handle 28 to allow a section of pipe to be placed in the throat 10 of the power tong. Pivotally attached at 30 to the door 26 is one end of a spring-loaded piston assembly 32. The other end of the piston assembly 32 is pivotally attached at 34 to the frame in order to retain the door in the open or closed position. The door and piston assembly are shown in the closed position in solid lines and ln the open position in phantom lines. Optionally, the door 26 may include a latch mechanism (not shown) which cooperates with a correspond-ing hook (not shown) mounted on the frame 2 so that the door 26 can be securely locked in place after a pipe section has been placed into the throat 10.
The pipe-gripping mechanism includes a partial ring 40 -which comprises a rotary gear mounted for rotation within the frame 2 and has an opening 42 which is adapted to align with the throat 10 of the frame. The ring 40 includes a projection 44 which extends around the outer circumference of the ring and defines upper and lower shoulders 46 and 48, respectively, which can abut against rollers, not shown, for support. Rigidly secured to the outer periphery of the projection 44 of the ring 40 are gear teeth 50.
The ring 40 may be rotated relative to the frame 2 by means of drive train 60 shown in Figures 2-4. The drive train 60 includes a motor 300 with a downwardly extending shaft 302 having a drive gear 304 mounted thereon. The drive gear 304 is mounted between the upper and lower plates 4 and 5 and rotates a pinion 400 having a pinion gear 404 which rotates with a shaft 402 rotatably mounted along the major axis of the tong assembly. The pinion 400 meshes with pinion idler gears 500 which are situated on either side of the pinion gear 91~
400. The point of contact of the pinion gear 400 with the pinion idler gears 500 is on a line substantially perpendicular to the major axis of the tong assembly. Pinion idler gears 500 rotate rotable idler gears 600, which in turn rotate the rotary gear associated with the partial ring 40.
Referring to Figure 4, the motor 300 is mounted above the upper plate at the rear end of the tong assembly. The motor 300 is a multiple speed motor, preferably a two speed motor having two speed ranges and two torque ranges. The motor is preferably hydraulically or pneumatically powered, and it has been found that hydraulic motor number C270S manufactured by the Staffa Company of Massachusetts, can be successfully used with the apparatus of this invention.
Associated with the motor is a drive shaEt 302 which is mounted on a shaft 306 and rotates therewith. The drive shaft 302 is journalled into a bearing 308 mounted in lower plate 5. Fixedly secured around drive shaft 302 is a drive gear 304 which rotates at two different speed and torque ranges and in either direction depending upon the desired operation to be performed. Drive gear 304 meshes with pinion gear 404 oE pinnon 400. Pinion 400 includes a vertical shaft 402 rotatably mounted and extending between upper and lower plates 4 and 5. The shaft 402 has bearings 406 mounted in surrounding engagement therewith for connecting the pinion gear 404 for rotation with the shaft 402. Spacers 408 are provided associated with snap rings 410 to vertically center the gear 404 between the upper and lower plates 4 and 5.
Pinion gear 404 meshes with pinion idler gear 504 which is part of the pinion idler assembly 500. The pinion idler assembly include a vertical shaft 502 rotatably mounted and extending between the upper and lower plates 4 and 5 and .
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the pinion idler gear 504 is fixedly mounted to the rotatable shaft 502 in a manner similar to the pinion assembly 400.
Pinion idler gear ~04 meshes in turn with the rotary idler gear 604.
Referring to Figure 3, the rotary idler assembly 600 is shown to include a vertical shaft 602 rotatably mounted and extending between the upper and lower plates 4 and 5 for rotation therein. Similarly mounted to the shaft 602 is a rotary idler gear 604 which is rotated by the pinion idler gear, not shown in Figure 3, which in turn rotates the partial ring 40 by meshing with gear teeth 50 mounted on the outer periphery of the partial ring 40. It is thus seen that the partial ring can be rotated in either direction at two speeds and at two different torques without interposition of complicated clutch mechanisms, thus avoiding damage to the gears during shifting.
The pipe-gripping mechanism further includes a die carrier 100 which is mounted for rotation on the tong and has an opening 101 which is adapted to align with the throat 10 of the frame and the opening 42 of the partial ring. The die carrier 100 includes upper and lower arcuate plates 102 and 104, respectively, spaced apart by spacer sleeves 106. The plates 102 and lOd~ are held in position by bolts 108 which have a lower threaded end portion 110 which is threaded into a threaded opening 112 in lower arcuate plate 104. The upper and lower arcuate plates 102 and 104 of the die carrier 100 have a plurality of guide wheels 114 rotatably mounted thereon. The guide wheels 114 are rotatably mounted on shafts by means of suitable bearings. The shafts extend through openings in the upper and lower arcuate plates 102 and 104 and are retained by nuts 120 housed in grooves 122 in the arcuate plates. These ~8~
guide wheels 114 ride in grooves 124 and 126 defined in the lower and upper surfaces, respectively, of the partial ring 40.
This construction permits the partial ring 40 and the die carrier 100 to rotate relative to one another. As will be appreciated, the grooves 124 and 126 may be defined in the upper and lower plates 102 and 104 of the dis carrier 100 and the guide wheels 114 rotatably mounted on the upper and lower plates 4 and 6 so that the die carrier is rotatably mounted on the frame rather than the partial ring, as described in the above-identified patent application.
Pivotally mounted to the die carrier 100 by hinge pins 130 and 132 are a pair of link members 134 and 136, respectively. The link members each include similarly shaped upper and lower arcuate wall portions. Only the upper wall portions 138 and 140 of the link members 134 and 136, respectively, are shown in the drawings. The link members also each include a cylindrically shaped side wall portion 142 and 143, respectively.
Each of the link members 134 and 136 normally carries a front die 144 and 146, respectively, and a rear die 148 and 150, respectively. The dies are mounted on the side wall portions 142 and 143. Each of the link members 134 and 136 also includes head rollers 152 and 154, respectively, which are rotatably mounted by head roller pins 156 and 158, respectively, between the arcuate upper and lower wall portions and act as cam followers. The front and rear dies are typically provided with serrated faces which grip the pipe section. Although front and read dies have been illustrated, it will be appreciated that each of the link members 134 and 136 may only carry one die with the dies mounted in opposed relationship.
The inner surfaces of the side portion of the partial ring 40 facing the throat 10 are provided with three arcuate _g_ .. :
lQ~ 8 depressions on both sides of the pipe section. These depressions are positioned adjacent the link members 134 and 136. Depressions 160 and 161 serve as a neutral cam surface for receiving the head rollers 152 and 154, respectively, when the pipe-gripping mechanism is in its initial rest position. The depressions 162 and 163 serve as cam surfaces for urging the front dies 144 and 146 into gripping engagement with the pipe section when the ring 40 is rotated in the clockwise direction. The depressions 164 and 165, in like manner, urge the front dies into gripping engagement with the pipe section when the ring 40 is rotated in the counterclockwise direction.
The cam surfaces 162, 163, 164, and 165 have a specially designed and critical "cam angle" which must be employed in order to properly engage the front and rear dies with the pipe -section. More particularly, the "cam angle" must be about 1/2 to 5-1/2 degrees, and preferably 2 to 3 degrees, with 2-1/2 degrees being most preferred to obtain the necessary enyagement for proper pipe handling.
The "cam angle" is defined as the angle formed ~y lines originating at the center of rotation of the partial ring 40 and a point on a line perpendicular to the center line of the throat 10 and passing through the center of rotation and terminating at the point on the cam surface at which the cam follower is positioned when the dies are in contact with the pipe section. The "cam angle" is illustrated as "A" in Figure 2. The angle "A" is constructed as follows using the cam surface 163 as illustrative. A point "B" on the cam surface 163 is found at which the dies 144, 146, 148, and 150 engage the pipe. This point "B" is independent of the pipe diameter since different si~e link members 134 and 136 are used depending upon the pipe diameter. A line "C" is drawn between the center 10~91~
of rotation oE the partial ring 40 and the point "B". A
line "D" is then drawn between point "B" at the angle "A" from line "C" so that the line "D" intersects a line "E" which is perpendicular to the center line "E"' of the throat at a point "G" which is between the center of rotation of the partial ring 40 and the neutral cam surface 162 which is adjacent point "B". The cam surface 163 and also the cam surface 165 form a portion of a circle having a center at point "G". The cam surfaces 162 and 164 are constructed in similar manner.
Referring now in more detail to the arrangement of the front and rear dies relative to the axis of rotation of the ring 40. It will be seen in Figure 2 that a circle drawn about this axis may be divided into four quadrants by the center line "F" of the throat 10 and the line "E" passing through the axis of rotation perpendicular to the center line. The rear dies 148 and 150 are located in adjacent rear quadrants and the front dies 144 and 146 are located in adjacent front quadrants of the circle. The link members 134 and 136 are so mounted that the cam surfaces ~rge the front dies 144 and 146 toward the pipe in an approximately radial direction. Accordingly, the front dies serve a dual purpose, namely, they not only grip the pipe section themselves but also urge the pipe section into engagement with the rear dies 148 and 150.
Mounted to the upper plate 4 of the frame 2 is an arcuate brake band 170 having flange portions 172. Bolts 174 extend through openings (not shown) in the flanges 172 and serve to attach the brake band 170 to brackets 176. The brackets 176 are welded to the upper plate 4 and the bolts 174 are retained by nuts 178. The brake bank 170 partially surrounds and frictionally engages the outer periphery of the upper plate 102 of the die carrier 100. The brake band 170 is restrained .
against vertical movement by retainers 180 which are bolted at 1~2 to the upper plate 4. Spring 184 is attached to brake bank 170 at the rear end to slightly tension the brake band away from the die carrier 100.
The bolt head of the rear bolt 108 is elongated to form a spacer 201. The top of the elongated bolt head has a threaded opening which receives the threaded end of bolt 190.
Pivotally mounted on bolt 190 is a retainer plate 192 which has an opening which receives backing pin 194. Backing pin 194 has a shoulder which retains the backing pin in retainer plate 192. Backing pin 194 can be inserted into one of openings 196 and 198 in the upper plate 102 of die carrier 100. Openings 196 and 198 are positioned one on either side of backing lug 200 when the opening 101 in the die carrier 100 is aligned with the opening 42 in the partial ring 40. The backing lug 200 is mounted in a recess in the upper surface of the partial ring 40. The backing lug 200 is retained in place by bolt 204 which is threaded into a threaded opening in the partial ring 40.
The backing pin 194 abuts against the backing lug 200 and causes the partial ring 40 and die carrier 100 to move in unison with their openings 42 and 101, respectively, aligned while the opening 42 in the partial ring 40 is being aligned with the throat 10 in the frame.
In operation, the opening 42 in the partial ring 40 is aligned with the throat 10 in the frame 2 so that the pipe section may be inserted into the interior of the partial ring. In inserting the pipe, the door 26 is pivoted open to allow the pipe to be placed in the throat 10 and then closed.
When inserted the exterior surface of the pipe section comes into contact with the rear dies 148 and 150 of link members 134 and 136, respectively, and the longitudinal axis of the pipe ~~
section is approximately coincident with the axis of rotation of the partial ring 40. After the p;pe section is in position, power is applied by the motor to rotate the partial ring 40 either clockwise or counterclockwiseO For the purpose of illustration, it will be assumed that the partial ring 40 is -rotated in a clockwise direction.
As the ring 40 begins to rotate in a clockwise direction from the posotion shown in Figure 1, the die carrier 100 will remain stationa~y because of the frictional engagement of the die carrier 100 with the brake band 170. Therefore, the cam surfaces 162 and 163 on the partial ring 40 will move relative to the cam followers 152 and 154 on the link members 134 and 136, respectively. Upon continued rotation of the ring 40, the cam surface 162 will cause the link member 134 to pivot in a counterclockwise direction about the hinge pin 130 upon which it is mounted and, in like manner, the cam surface 163 will cause the link member 136 to pivot in a clockwise direction about its hinge pin 132. These movements of the link member 134 and 136 will bring the front dies 144 and 146 into gripping engagement with the surface of the pipe section. Because of the specially designed cam surfaces and the carefully selected "cam angle", the force exerted by the dies on the pipe is concentrated at or near the center of rotation of the pipe section. Moreover, the force is evenly distributed and controlled so that the pipe is gripped tightly enough to allow proper torque to be applied without crushing or damaging the pipe.
After the front dies 144 and 146 are brought into contact with the pipe section, further relative movement between the cam followers 152 and 154 and the cam surfaces 162 and 163 is not possible. Accordingly, the die carrier 100 will begin to rotate in unison with the ring 40. The pipe section, .
.. . . . . .
~Q~9~3 being tightly gripped by the front and rear dies against relative movement with respect to the die carrier, also will begin to rotate in a clockwise direction. This rotation may be continued for as many revolutions as may be required in order to make up or break apart a threadecl connection between one end of the pipe section and another pipe section positioned in alignment therewith~
After the pipe section has been rotated sufficiently to make up or brake apart the joint, the tong may be freed from the pipe section by rotating the ring 40 in the opposite direction, namely, in the counterclockwise direction in terms of this illustration, to position the cam followers 152 and 154 in the neutral cam surfaces 160 and 161, respectively. With the parts in this position, the front dies 144 and 146 may be disengaged from the pipe section and the tong may be moved rearwardly to free the rear dies 148 and 150 from contact with the surface of the pipe section. Thereafter, the ring 40 may be further rotated in the counterclockwise direction, if necessary, to position its opening 42 in alignment with the throat 10.
The rotation~of ring 40 will also cause die carrier 100 to be rotated back into its initial rest position by reason of the cooperation between backing pin 194 and backing lug 200 so that the pipe section may pass out of the tong.
As will be appreciated, the tong is also capable of rotating the pipe section in a counterclockwise direction. In order to accomplish this, the tong is operated in a manner substantially as described above, the only difference being that the partial ring 40 is rotated in the opposite direction and the cam surfaces 164 and 165 on the partial ring 40 cooperate with the cam followers 152 and 154.
It is to be understood that while one form of the invention has been illustrated, there are other forms which fall within the scope of the invention. For example, the linkmembers which carry the dies can be mounted on the die carrier so that the link members are moved perpendicular to the center line of the throat of the partial ring at all times rather than pivotally. Further, the drive mechanism utilizing a two-speed motor with a single gear train can be utilized in spinner mechanisms for spinning sections of a pipe after the joints are broken by a power tong assembly. Accordingly, the invention is not to be limited to such specific form except as provided by the appended claims.
- , . .
:. ~ . :. , ' ' , , . , : : : ' . . .
An improved pipe-gripping mechanism and means for urging the mechanism into contact with the pipe is described in the above-identified patent application. In that application, the power unit for transmitting power to the pipe-gripping mechanism comprises a single speed motor having a gear train :~ i . .. . .
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which transforms the single rotational speed of the motor sha~t into two speed movement of the partial ring. The gear train includes a motor drive gear meshing with a clutch assembly including a low-speed clutch gear and a high speed clutch gear which is selectively actuated by moving a shifting collar which surrounds the clutch shaft by a conventional shifting assembly.
The low and high speed clutch gears mesh with low and high speed pinnon gears which are carried by a sleeve. The sleeve includes gear teeth which mesh pinion idler gears, which in turn drive rotary idler gears which mesh with gear teeth on the partial ring. Such a power unit has a number of undesirable features.
It is required that the gears be-manually shifted in order to provide the desired speed and torque requirements to rotate the partial ring. Since such clutch assel~lies required for shifting do not include a synchromesh arrangement, which would be too costly, problems in aligning the gears to mesh perfectly without damage to the gears frequently occurs. Further, the increased cost associated with multiple gears and clutch assemblies has proved undesirable and less efficient than the present invention.
Accordingly, an object of the present invention is to provide a power tong for making up and taking apart joints of drill pipe, casing, tubing, and the like having an improved drive assembly.
Another object of the invention is to provide a power tong having an improved drive assembly comprising a multiple speed motor, preferably a two speed motor and a drive train that eliminates shifting and reduces the number of moving parts.
It is still further an object of this invention to provide a multiple speed hydraulic or pneumatic motor having two speed ranges and two torque ranges that is coupled directly ~O~B918 through a single series of gears to rotate the partial ring, thus urging the pipe-gripping mechanism into contact with the pipe to be rotated.
Accordi~g to the invention, an improved power tong for rotating a pipe comprises a frame having a throat for re-ceiving a pipe, a partial ring rotatably mounted on said frame and having an opening therein which is adapted to be aligned with said throat so that a pipe may be positioned within said partial ring, said partial ring defining cam surfaces having a cam angle of about 1/2 to 5-1/2 degrees positioned on opposite sides of the center line of said opening, means for rotating said partial ring about its central axis, die means operatively associated with said partial ring, said die means including dies positioned on opposite sides of said center line of said opening, rotation of said partial ring causing said cam surfaces to move said die means inwardly so that said dies grip the pipe on opposite sides thereof for turning movement of said pipe, and said means for rotating said partial ring comprising a vari-able speed motor mounted on said frame, and a drive train compri-sing a plurality of gears coupling said motor to said partial ring.
In the preferred embodiment, the partial ring may be rotated in either the clockwise or counterclockwise direction by the power unit and drive train which cooperates with gear teeth rigidly fixed to the ring.
The power unit and drive train preferably comprises a multiple speed hydraulic or pneumatic motor, preferably a two-speed motor, that has two speed ranges and two torque ranges.
The motor is mounted on the rearward portion of the tong assembly -and comprises a drive shaft with a gear mounted thereon. A
~ _4_ ... ,~ :
.: ; , 1~)i5 ~39~8 pinion gear assembly meshes with the drive gear of the motor and is rotated in either direction at either speed or torque range.
A pair of pinion idler gears mesh with the pinion gear and in turn drive rotary idler gears which are positioned adjacent a rotary gear mounted on the parital r:ing. The rotary gear rota-tion drives the partial ring in a desired direction for moving the pipe mechanism into -4a-~88~L8 engagement with the pipe to be rotated.
A die carrier is mounted on the tong and is rotatable relative to the ring. The die carr:ier includes link members which are pivotally mounted on the carrier and have dies positioned to grip the external surface of the pipe section which is to be rotated. The link members are arranged to cooperate with specially designed cam surfaces on the ring so that, when the ring is rotated relative to the die carrier, the dies are moved into engagement with the pipe section. After the movable dies have engaged the pipe section, further relative movement between the ring and the die carrier is prevented and the pipe section is therefore rotated to make up or break apart a threaded joint of pipe.
Figure 1 is a plan view of the front portion of a power tong according to the invention;
Figure 2 is a plan view of the entire power tong of Figure 1 with the top plate of the frame, the door and the die carrier removed;
Figure 3 is a vertical cross section view taken along ~ -20 the lines 3-3 in Figure 2 to show the rotary gear-rotary idler arrangement; and J Figure 4 is a vertical cross section view taken along the line 4-4 in Figure 2 to show the motor drive, pinion gear, and pinion idler arrangement.
Referring now in detail to the drawings, the frame 2 of the power tong includes an upper plate 4 and a lower plate 5 spaced apart and bolted to the sidewalls 7. The frame 2 has an arcuate front portion defining a throat 10 for receiving a pipe section such as a section of drill pipe, casing, tubing 30 or the like.
Pivotally mounted to the frame 2 adjacent the throat :' ' :' ' , ' . ',, . , 10 by means of a hinge pin 24 is a door 26 which may be opened by means of handle 28 to allow a section of pipe to be placed in the throat 10 of the power tong. Pivotally attached at 30 to the door 26 is one end of a spring-loaded piston assembly 32. The other end of the piston assembly 32 is pivotally attached at 34 to the frame in order to retain the door in the open or closed position. The door and piston assembly are shown in the closed position in solid lines and ln the open position in phantom lines. Optionally, the door 26 may include a latch mechanism (not shown) which cooperates with a correspond-ing hook (not shown) mounted on the frame 2 so that the door 26 can be securely locked in place after a pipe section has been placed into the throat 10.
The pipe-gripping mechanism includes a partial ring 40 -which comprises a rotary gear mounted for rotation within the frame 2 and has an opening 42 which is adapted to align with the throat 10 of the frame. The ring 40 includes a projection 44 which extends around the outer circumference of the ring and defines upper and lower shoulders 46 and 48, respectively, which can abut against rollers, not shown, for support. Rigidly secured to the outer periphery of the projection 44 of the ring 40 are gear teeth 50.
The ring 40 may be rotated relative to the frame 2 by means of drive train 60 shown in Figures 2-4. The drive train 60 includes a motor 300 with a downwardly extending shaft 302 having a drive gear 304 mounted thereon. The drive gear 304 is mounted between the upper and lower plates 4 and 5 and rotates a pinion 400 having a pinion gear 404 which rotates with a shaft 402 rotatably mounted along the major axis of the tong assembly. The pinion 400 meshes with pinion idler gears 500 which are situated on either side of the pinion gear 91~
400. The point of contact of the pinion gear 400 with the pinion idler gears 500 is on a line substantially perpendicular to the major axis of the tong assembly. Pinion idler gears 500 rotate rotable idler gears 600, which in turn rotate the rotary gear associated with the partial ring 40.
Referring to Figure 4, the motor 300 is mounted above the upper plate at the rear end of the tong assembly. The motor 300 is a multiple speed motor, preferably a two speed motor having two speed ranges and two torque ranges. The motor is preferably hydraulically or pneumatically powered, and it has been found that hydraulic motor number C270S manufactured by the Staffa Company of Massachusetts, can be successfully used with the apparatus of this invention.
Associated with the motor is a drive shaEt 302 which is mounted on a shaft 306 and rotates therewith. The drive shaft 302 is journalled into a bearing 308 mounted in lower plate 5. Fixedly secured around drive shaft 302 is a drive gear 304 which rotates at two different speed and torque ranges and in either direction depending upon the desired operation to be performed. Drive gear 304 meshes with pinion gear 404 oE pinnon 400. Pinion 400 includes a vertical shaft 402 rotatably mounted and extending between upper and lower plates 4 and 5. The shaft 402 has bearings 406 mounted in surrounding engagement therewith for connecting the pinion gear 404 for rotation with the shaft 402. Spacers 408 are provided associated with snap rings 410 to vertically center the gear 404 between the upper and lower plates 4 and 5.
Pinion gear 404 meshes with pinion idler gear 504 which is part of the pinion idler assembly 500. The pinion idler assembly include a vertical shaft 502 rotatably mounted and extending between the upper and lower plates 4 and 5 and .
,., . . , .. ; : , . :
Q~
the pinion idler gear 504 is fixedly mounted to the rotatable shaft 502 in a manner similar to the pinion assembly 400.
Pinion idler gear ~04 meshes in turn with the rotary idler gear 604.
Referring to Figure 3, the rotary idler assembly 600 is shown to include a vertical shaft 602 rotatably mounted and extending between the upper and lower plates 4 and 5 for rotation therein. Similarly mounted to the shaft 602 is a rotary idler gear 604 which is rotated by the pinion idler gear, not shown in Figure 3, which in turn rotates the partial ring 40 by meshing with gear teeth 50 mounted on the outer periphery of the partial ring 40. It is thus seen that the partial ring can be rotated in either direction at two speeds and at two different torques without interposition of complicated clutch mechanisms, thus avoiding damage to the gears during shifting.
The pipe-gripping mechanism further includes a die carrier 100 which is mounted for rotation on the tong and has an opening 101 which is adapted to align with the throat 10 of the frame and the opening 42 of the partial ring. The die carrier 100 includes upper and lower arcuate plates 102 and 104, respectively, spaced apart by spacer sleeves 106. The plates 102 and lOd~ are held in position by bolts 108 which have a lower threaded end portion 110 which is threaded into a threaded opening 112 in lower arcuate plate 104. The upper and lower arcuate plates 102 and 104 of the die carrier 100 have a plurality of guide wheels 114 rotatably mounted thereon. The guide wheels 114 are rotatably mounted on shafts by means of suitable bearings. The shafts extend through openings in the upper and lower arcuate plates 102 and 104 and are retained by nuts 120 housed in grooves 122 in the arcuate plates. These ~8~
guide wheels 114 ride in grooves 124 and 126 defined in the lower and upper surfaces, respectively, of the partial ring 40.
This construction permits the partial ring 40 and the die carrier 100 to rotate relative to one another. As will be appreciated, the grooves 124 and 126 may be defined in the upper and lower plates 102 and 104 of the dis carrier 100 and the guide wheels 114 rotatably mounted on the upper and lower plates 4 and 6 so that the die carrier is rotatably mounted on the frame rather than the partial ring, as described in the above-identified patent application.
Pivotally mounted to the die carrier 100 by hinge pins 130 and 132 are a pair of link members 134 and 136, respectively. The link members each include similarly shaped upper and lower arcuate wall portions. Only the upper wall portions 138 and 140 of the link members 134 and 136, respectively, are shown in the drawings. The link members also each include a cylindrically shaped side wall portion 142 and 143, respectively.
Each of the link members 134 and 136 normally carries a front die 144 and 146, respectively, and a rear die 148 and 150, respectively. The dies are mounted on the side wall portions 142 and 143. Each of the link members 134 and 136 also includes head rollers 152 and 154, respectively, which are rotatably mounted by head roller pins 156 and 158, respectively, between the arcuate upper and lower wall portions and act as cam followers. The front and rear dies are typically provided with serrated faces which grip the pipe section. Although front and read dies have been illustrated, it will be appreciated that each of the link members 134 and 136 may only carry one die with the dies mounted in opposed relationship.
The inner surfaces of the side portion of the partial ring 40 facing the throat 10 are provided with three arcuate _g_ .. :
lQ~ 8 depressions on both sides of the pipe section. These depressions are positioned adjacent the link members 134 and 136. Depressions 160 and 161 serve as a neutral cam surface for receiving the head rollers 152 and 154, respectively, when the pipe-gripping mechanism is in its initial rest position. The depressions 162 and 163 serve as cam surfaces for urging the front dies 144 and 146 into gripping engagement with the pipe section when the ring 40 is rotated in the clockwise direction. The depressions 164 and 165, in like manner, urge the front dies into gripping engagement with the pipe section when the ring 40 is rotated in the counterclockwise direction.
The cam surfaces 162, 163, 164, and 165 have a specially designed and critical "cam angle" which must be employed in order to properly engage the front and rear dies with the pipe -section. More particularly, the "cam angle" must be about 1/2 to 5-1/2 degrees, and preferably 2 to 3 degrees, with 2-1/2 degrees being most preferred to obtain the necessary enyagement for proper pipe handling.
The "cam angle" is defined as the angle formed ~y lines originating at the center of rotation of the partial ring 40 and a point on a line perpendicular to the center line of the throat 10 and passing through the center of rotation and terminating at the point on the cam surface at which the cam follower is positioned when the dies are in contact with the pipe section. The "cam angle" is illustrated as "A" in Figure 2. The angle "A" is constructed as follows using the cam surface 163 as illustrative. A point "B" on the cam surface 163 is found at which the dies 144, 146, 148, and 150 engage the pipe. This point "B" is independent of the pipe diameter since different si~e link members 134 and 136 are used depending upon the pipe diameter. A line "C" is drawn between the center 10~91~
of rotation oE the partial ring 40 and the point "B". A
line "D" is then drawn between point "B" at the angle "A" from line "C" so that the line "D" intersects a line "E" which is perpendicular to the center line "E"' of the throat at a point "G" which is between the center of rotation of the partial ring 40 and the neutral cam surface 162 which is adjacent point "B". The cam surface 163 and also the cam surface 165 form a portion of a circle having a center at point "G". The cam surfaces 162 and 164 are constructed in similar manner.
Referring now in more detail to the arrangement of the front and rear dies relative to the axis of rotation of the ring 40. It will be seen in Figure 2 that a circle drawn about this axis may be divided into four quadrants by the center line "F" of the throat 10 and the line "E" passing through the axis of rotation perpendicular to the center line. The rear dies 148 and 150 are located in adjacent rear quadrants and the front dies 144 and 146 are located in adjacent front quadrants of the circle. The link members 134 and 136 are so mounted that the cam surfaces ~rge the front dies 144 and 146 toward the pipe in an approximately radial direction. Accordingly, the front dies serve a dual purpose, namely, they not only grip the pipe section themselves but also urge the pipe section into engagement with the rear dies 148 and 150.
Mounted to the upper plate 4 of the frame 2 is an arcuate brake band 170 having flange portions 172. Bolts 174 extend through openings (not shown) in the flanges 172 and serve to attach the brake band 170 to brackets 176. The brackets 176 are welded to the upper plate 4 and the bolts 174 are retained by nuts 178. The brake bank 170 partially surrounds and frictionally engages the outer periphery of the upper plate 102 of the die carrier 100. The brake band 170 is restrained .
against vertical movement by retainers 180 which are bolted at 1~2 to the upper plate 4. Spring 184 is attached to brake bank 170 at the rear end to slightly tension the brake band away from the die carrier 100.
The bolt head of the rear bolt 108 is elongated to form a spacer 201. The top of the elongated bolt head has a threaded opening which receives the threaded end of bolt 190.
Pivotally mounted on bolt 190 is a retainer plate 192 which has an opening which receives backing pin 194. Backing pin 194 has a shoulder which retains the backing pin in retainer plate 192. Backing pin 194 can be inserted into one of openings 196 and 198 in the upper plate 102 of die carrier 100. Openings 196 and 198 are positioned one on either side of backing lug 200 when the opening 101 in the die carrier 100 is aligned with the opening 42 in the partial ring 40. The backing lug 200 is mounted in a recess in the upper surface of the partial ring 40. The backing lug 200 is retained in place by bolt 204 which is threaded into a threaded opening in the partial ring 40.
The backing pin 194 abuts against the backing lug 200 and causes the partial ring 40 and die carrier 100 to move in unison with their openings 42 and 101, respectively, aligned while the opening 42 in the partial ring 40 is being aligned with the throat 10 in the frame.
In operation, the opening 42 in the partial ring 40 is aligned with the throat 10 in the frame 2 so that the pipe section may be inserted into the interior of the partial ring. In inserting the pipe, the door 26 is pivoted open to allow the pipe to be placed in the throat 10 and then closed.
When inserted the exterior surface of the pipe section comes into contact with the rear dies 148 and 150 of link members 134 and 136, respectively, and the longitudinal axis of the pipe ~~
section is approximately coincident with the axis of rotation of the partial ring 40. After the p;pe section is in position, power is applied by the motor to rotate the partial ring 40 either clockwise or counterclockwiseO For the purpose of illustration, it will be assumed that the partial ring 40 is -rotated in a clockwise direction.
As the ring 40 begins to rotate in a clockwise direction from the posotion shown in Figure 1, the die carrier 100 will remain stationa~y because of the frictional engagement of the die carrier 100 with the brake band 170. Therefore, the cam surfaces 162 and 163 on the partial ring 40 will move relative to the cam followers 152 and 154 on the link members 134 and 136, respectively. Upon continued rotation of the ring 40, the cam surface 162 will cause the link member 134 to pivot in a counterclockwise direction about the hinge pin 130 upon which it is mounted and, in like manner, the cam surface 163 will cause the link member 136 to pivot in a clockwise direction about its hinge pin 132. These movements of the link member 134 and 136 will bring the front dies 144 and 146 into gripping engagement with the surface of the pipe section. Because of the specially designed cam surfaces and the carefully selected "cam angle", the force exerted by the dies on the pipe is concentrated at or near the center of rotation of the pipe section. Moreover, the force is evenly distributed and controlled so that the pipe is gripped tightly enough to allow proper torque to be applied without crushing or damaging the pipe.
After the front dies 144 and 146 are brought into contact with the pipe section, further relative movement between the cam followers 152 and 154 and the cam surfaces 162 and 163 is not possible. Accordingly, the die carrier 100 will begin to rotate in unison with the ring 40. The pipe section, .
.. . . . . .
~Q~9~3 being tightly gripped by the front and rear dies against relative movement with respect to the die carrier, also will begin to rotate in a clockwise direction. This rotation may be continued for as many revolutions as may be required in order to make up or break apart a threadecl connection between one end of the pipe section and another pipe section positioned in alignment therewith~
After the pipe section has been rotated sufficiently to make up or brake apart the joint, the tong may be freed from the pipe section by rotating the ring 40 in the opposite direction, namely, in the counterclockwise direction in terms of this illustration, to position the cam followers 152 and 154 in the neutral cam surfaces 160 and 161, respectively. With the parts in this position, the front dies 144 and 146 may be disengaged from the pipe section and the tong may be moved rearwardly to free the rear dies 148 and 150 from contact with the surface of the pipe section. Thereafter, the ring 40 may be further rotated in the counterclockwise direction, if necessary, to position its opening 42 in alignment with the throat 10.
The rotation~of ring 40 will also cause die carrier 100 to be rotated back into its initial rest position by reason of the cooperation between backing pin 194 and backing lug 200 so that the pipe section may pass out of the tong.
As will be appreciated, the tong is also capable of rotating the pipe section in a counterclockwise direction. In order to accomplish this, the tong is operated in a manner substantially as described above, the only difference being that the partial ring 40 is rotated in the opposite direction and the cam surfaces 164 and 165 on the partial ring 40 cooperate with the cam followers 152 and 154.
It is to be understood that while one form of the invention has been illustrated, there are other forms which fall within the scope of the invention. For example, the linkmembers which carry the dies can be mounted on the die carrier so that the link members are moved perpendicular to the center line of the throat of the partial ring at all times rather than pivotally. Further, the drive mechanism utilizing a two-speed motor with a single gear train can be utilized in spinner mechanisms for spinning sections of a pipe after the joints are broken by a power tong assembly. Accordingly, the invention is not to be limited to such specific form except as provided by the appended claims.
- , . .
:. ~ . :. , ' ' , , . , : : : ' . . .
Claims (5)
1. An improved power tong for rotating a pipe com-prising a frame having a throat for receiving a pipe, a partial ring rotatably mounted on said frame and having an opening there-in which is adapted to be aligned with said throat so that a pipe may be positioned within said partial ring, said partial ring defining cam surfaces having a cam angle of about 1/2 to 5-1/2 degrees positioned on opposite sides of the center line of said opening, means for rotating said partial ring about its central axis, die means operatively associated with said partial ring, said die means including dies positioned on opposite sides of said center line of said opening, rotation of said partial ring causing said cam surfaces to move said die means inwardly so that said dies grip the pipe on opposite sides thereof for turning movement of said pipe, and said means for rotating said partial ring comprising a variable speed motor mounted on said frame, and a drive train comprising a plurality of gears coupling said motor to said partial ring.
2. The power tong as claimed in claim 1, wherein said variable speed motor comprises a two-speed, reversible fluid pressure actuated motor.
3. A power tong as claimed in claim 2, wherein said fluid pressure actuated motor comprises a hydraulic motor.
4. A power tong as claimed in claim 2, wherein said fluid pressure actuated motor comprises a pneumatic motor.
5. A power tong as claimed in claim 1 or 2, wherein said drive train comprises a drive gear, a pinion gear having gear teeth which mesh with said drive gear, a pair of pinion idler gears having gear teeth which mesh with the gear teeth of said pinion gear, a pair of rotary idler gears having gear teeth which mesh with the gear teeth of said pinion idler gears, and said rotary idler teeth also mesh with gear teeth mounted on the periphery of said partial ring for rotating said partial ring.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US77666077A | 1977-03-11 | 1977-03-11 | |
| US776,660 | 1977-03-11 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1088918A true CA1088918A (en) | 1980-11-04 |
Family
ID=25108043
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA298,657A Expired CA1088918A (en) | 1977-03-11 | 1978-03-10 | Power tong drive mechanism |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1088918A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5144868A (en) * | 1990-05-08 | 1992-09-08 | Feigel Kurt R Jr | Power tongs |
| US6279426B1 (en) * | 2000-04-28 | 2001-08-28 | Eckel Manufacturing Company, Inc. | Power tong with improved door latch |
| US9010219B2 (en) | 2010-06-07 | 2015-04-21 | Universe Machine Corporation | Compact power tong |
| CN111042751A (en) * | 2019-11-25 | 2020-04-21 | 贵州高峰石油机械股份有限公司 | Pulse torsion reversing device for well repair |
-
1978
- 1978-03-10 CA CA298,657A patent/CA1088918A/en not_active Expired
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5144868A (en) * | 1990-05-08 | 1992-09-08 | Feigel Kurt R Jr | Power tongs |
| US6279426B1 (en) * | 2000-04-28 | 2001-08-28 | Eckel Manufacturing Company, Inc. | Power tong with improved door latch |
| GB2363351B (en) * | 2000-04-28 | 2003-12-03 | Eckel Mfg Company Inc | Power tong with improved door latch |
| US9010219B2 (en) | 2010-06-07 | 2015-04-21 | Universe Machine Corporation | Compact power tong |
| CN111042751A (en) * | 2019-11-25 | 2020-04-21 | 贵州高峰石油机械股份有限公司 | Pulse torsion reversing device for well repair |
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| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |