Patent Grant
8997608
The present patent application is related to copending application Ser. No. 13/767,727 entitled NUT REMOVAL TOOL filed on Feb. 14, 2013; and copending application FLIP SOCKET NUT REMOVAL TOOL having application Ser. No. 13/767,746 filed on Feb. 14, 2013; and copending application SOCKET FASTENER REMOVAL TOOL having application Ser. No. 13/767,771 filed on Feb. 14, 2013; and copending application DUTCHMAN FASTENER REMOVAL TOOL having application Ser. No. 13/767,758 filed on Feb. 14, 2013.
The invention relates to a stud removal tool. More particularly, this invention relates to a tool for the removal of rusted or broken threaded members, such as studs, from a threaded aperture.
Studs are a type of fastener with a threaded cylindrical barrel on one end of the fastener that mates with a complementary thread in a fixture. Commonly studs are removed by tightening two nuts together on the accessible threaded side of the stud, and then applying a counterclockwise rotational force to one of the nuts. This technique for stud removal is much more difficult for a stud that has been corroded or has been in the same place for some time. Studs that have been corroded or have been in place for some time are prone to breaking, and so there is a need for a removal tool for broken studs.
A further complication of using manual tools for large stud removal, such as studs used in oil production, is that manual removal of such damaged studs presents danger to the operator. Further, manual removal may be impossible because the degree of torque required is greater than the strength of the operator.
One type of device accomplishes removal by cutting the stud out of the fixture using a blow torch. However, this method of stud removal results in damage to the stud and the fixture. One solution is to use devices that either drill the stud, or cut into the stud, so that torque can be applied to the nut for removal. However, these devices also result in further stripping of the threads of the stud, impeding removal from the fixture.
Another type of device accomplishes fastener removal by inserting an electrode into the broken stud and using a series of intermittent electrical arcs to disintegrate the stud, leaving a stud casing which is then removed manually. Finally the threads of the fixture are cleaned. However, this method of removal results in damage to the stud, is time consuming, involves multiple steps for stud removal, and may result in damage to the fixture.
Other devices using an air impact tool for the removal of large studs exist. Such devices may require a cartridge having many small parts that is used to apply torque to the damaged stud. These multiple small parts of the cartridge, such as multiple helical springs, studs and screws holding gripping jaws together, are prone to breakage when the rotative force of an air impact tool is applied.
Another prior art stud removal tool consists of a housing having a cylindrical bore with finger splits on one end of the housing, and the other end of the housing connecting to an air impact tool. However, the finger splits of the housing cannot fit over multiple stud sizes, so that the tool is limited in usage.
A further complication of the cartridges and associated parts is the use of a retaining ring or clip. The retaining ring or clip is prone to breakage, resulting in a damaged and useless tool.
Another complication of stud removal is side loading, or the mechanical binding of threaded surfaces against each other. When side loading occurs, heat builds up due to friction between the threaded surfaces, creating a gall which is carried through the housing, tearing out the threads and impeding stud removal.
Yet another complication is “chattering,” where the tool does not perfectly conform to the size of the fastener. When rotative force is applied using an air impact tool, the removing tool “chatters” over the damaged corners of the fastener, further stripping the fastener or damaging the tool interface with the fastener, and causing ‘radii’ to form on the end of the tool.
The use of a set of tools having a multiplicity of sizes to conform to different stud sizes exists which proposes to solve the problem of imperfect conformance between removal tool and stud size. However, regardless of the size, the prior art nonetheless results in chattering from an imperfect size conformance; thus, stripping of the thread occurs.
Further, the use of a set of tools having a multiplicity of sizes to conform to stud size presents another complication. If there exists a multiplicity of removal tool sizes in a set, the loss of one of the tools results in a useless tool set.
It would thus be desirable to have a stud removal tool that conforms to the size and shape of a multiplicity of studs, where the jaws of the tool comprise one piece, rather than a multiplicity of smaller pieces which can be easily lost or damaged, and where the jaws are retained within the housing through a shock-absorbing canted coil spring.
An apparatus for removing a stud is described. The apparatus includes a housing, a cage, and a canted coil spring. The housing has a top end, a bottom end, and a middle section disposed between the top end and the bottom end. The top end includes a top surface and an interior sidewall. The top surface has an orifice that extends through the top end. The interior sidewall extends from the top surface to a lip. The interior sidewall includes a three-lobed cam and a groove. The three-lobed cam is disposed along the interior sidewall of the top end. Each lobe has a lobe center line and a counterclockwise cam inner surface on one side of the lobe center line, and a clockwise cam inner surface on the opposite side of the lobe center line. The groove is disposed between the top surface and the lip.
The cage has a top surface, a bottom portion ending in a tapered terminus and a groove disposed in the bottom portion between the top surface and the tapered terminus. The cage includes a plurality of jaws. Each jaw includes a jaw outer cam surface and an inner frictional surface. The jaw outer cam surface interfaces with the cam inner surface corresponding to the interior sidewall. The inner frictional surface interfaces with the stud. The canted coil spring is received by the groove of the interior sidewall and the groove of the cage. The canted coil spring is rotatably coupled the cage to the housing. During stud removal, the housing rotates counterclockwise relative to the cage. The cage rotates counterclockwise to engage the stud, and the cage interfaces with the interior sidewall. The canted coil spring operates within a constant deflection range, when an axial load is applied by the housing and the cage.
In one embodiment, the canted coil spring has the coils canted in a clockwise direction. In another embodiment, the canted coil spring has the coils canted in a counterclockwise direction.
In the illustrative embodiment, the lobe center line for each lobe is 120° apart, each lobe occupies a 120° arc, the counterclockwise cam interface has a 60° arc, and the clockwise cam interface has a 60° arc. In the illustrative embodiment, each lobe is substantially semi-circular. In a further illustrative embodiment, each jaw outer cam surface occupies a 60° arc.
In the illustrative embodiment, the jaw outer cam surface is configured to engage with the counterclockwise cam interface when a counterclockwise force is applied to the housing. In a further embodiment, the jaw outer cam surface is configured to engage with the clockwise cam interface when a clockwise force is applied to the housing.
In another illustrative embodiment, an elastomeric component is configured to join the plurality of jaws.
In the illustrative embodiment, the bottom end interfaces with an impact rotary tool that can oscillate between applying a counterclockwise force and a clockwise force. Additionally, the bottom end further comprises a slot that receives a pin that is inserted within the slot when the housing interfaces with the impact rotary tool.
Persons of ordinary skill in the art will realize that the following description is illustrative and not in any way limiting. Other embodiments of the claimed subject matter will readily suggest themselves to such skilled persons having the benefit of this disclosure. It shall be appreciated by those of ordinary skill in the art that the apparatus and systems described herein may vary as to configuration and as to details. Additionally, the methods may vary as to details, order of the actions, or other variations without departing from the illustrative method disclosed herein.
The stud removal tool described herein is used for the removal of rusted or broken threaded members, such as studs, from a threaded aperture in a fixture. Generally, the removal of the stud employs an impact wrench tool. Alternatively, other tools that provide needed torque may also be used. By way of example and not of limitation, the stud removal tool described herein may be used to remove studs that are deployed in oil production or power generation.
For purposes of this patent, the terms “cage” and “cartridge” will be used interchangeably. By way of example and not of limitation, the cage “floats” or rests on an illustrative canted coiled spring which is used to engage the cage with a housing that receives a counterclockwise force.
For purposes of this patent, the terms “fastener” and “stud” will be used interchangeably. Fasteners are generally cylindrical and have a threaded end which mates with complementary threads within a fixture. Studs and threaded rods do not have heads; studs may have a threaded top portion and a threaded bottom portion with a middle section that does not have threads.
The canted coil spring is presented in the illustrative spring technology that allows the cage to rotate freely, while ensuring that the cage does not slide out of the housing. Alternatively, a knitted spring tube may also be used instead of the canted coil spring. The canted coil spring and the knitted spring tube may also be referred to as a seal preload device. Other spring technologies may also be used that allow the cage (which grips the stud) and the housing (which interfaces with the cage) to rotate freely in either a counterclockwise or counterclockwise direction, while at the same time ensuring that the cage does not slide out of the housing.
Additionally, the illustrative embodiment presented herein includes a three-lobed cam along the interior sidewall of the housing as described in further detail below. The three-lobed cam is configured to interface with the cage, which interfaces with a stud. Each lobe of the illustrative three-lobed cam occupies a 120° arc and has a lobe centerline, a counterclockwise cam inner surface on one side of the lobe centerline, and a clockwise cam inner surface on the opposite side of the lobe centerline.
Generally, a counterclockwise force (to loosen stud) is applied to the housing for stud removal, this counterclockwise force is transferred to the cage, when the cage interfaces with the counterclockwise cam inner surface. There may be instances when additional torque is applied during stud removal and this may require the application of a clockwise force (tightening the stud), and then reverting back to the counterclockwise force.
The three-lobed cam described below is provided for illustrative purposes only. Alternatively, other lobed cam assemblies may also be used such as a two-lobed cam, a four-lobed cam, five-lobed cam, etc. The number of lobes and configuration of each lobe will depend on the particular application.
Referring to
The top end 24 also has a shaft thickness greater than middle section 23 shaft thickness. The top end 24 includes a top surface having an orifice defined by internal sidewall 29 that extends throughout the top end 24 portion. The interior sidewall 29 extends from the top surface 26 to a lip (not shown). The interior sidewall 29 includes a plurality of cam inner surfaces 30a, 30b and 30c along the interior sidewall 29 of the top end 24.
By way of example and not of limitation, the housing 20 is constructed of heat treated S7 steel that measures 52-54 on the Rockwell C scale, as measured with a Hardness Tester, such as that described in U.S. Pat. No. 1,294,171, “HARDNESS TESTER,” Hugh M. Rockwell and Stanley P. Rockwell, issued Feb. 11, 1919. S7 steel is a shock-resistant, air-hardening steel used for tools, and which is designed for high impact resistance at relatively high hardness in order to withstand chipping and breaking. Other alloys may also be used. Steels used are not plated or coated, other than surface treatment to produce a black oxide finish for corrosion resistance.
A canted coil spring 36 rests within a groove in the top end 24 section.
As shown in
In the illustrative embodiment, the bottom end is configured to receive an impact rotary tool. The bottom end may further include a slot 120 configured to receive a pin 122 that is inserted within the slot 120 when the housing 20 is configured to interface with a rotary tool. The pin 122 holds the rotary tool in place.
More generally, the stud removal tool 10 includes a fastening component with a biasing element that is configured to allow the cage 40 and the housing 20 to rotate freely in a counterclockwise or clockwise direction, and also enables the cage 40 to stay within the housing 20 during stud removal operations. The illustrative fastening component with the biasing element presented herein includes a seal preload device such as a canted coil spring. An alternative biasing element may include a clip.
The illustrative embodiment may include one of two types of canted coil springs, as shown in
Referring now to
As described in further detail below, the canted coil spring 36 is installed within grooves in both the housing 20 and the cage 40. The canted coil spring design may be designed according to the following illustrative parameters, namely, the wire material, the wire diameter, the cant amplitude, the coils per inch, the size controlled by spring width, and eccentricity. The cant amplitude is the axial distance the top coil is shifted compared to a helical spring. The eccentricity is a parameter that indicates a circular cross section; as the eccentricity increases the spring becomes more elliptical. Some manufacturers use other parameters to design a canted coil spring such as the front angle and the back angle instead of coils per inch and cant amplitude.
When a canted coil spring is deformed, the top of the coils slide against the contact surface and the bottom coils rotate about their axis. For example, the bottom of the spring is constrained axially so the coefficient of friction is greater at the contact between the spring and the bottom surface than the spring and the top surface. This process enables the cage to “float” on the canted coil spring.
Another illustrative seal preload device is a knitted spring tube shown in
Other parameters to consider for designing canted coil springs and knitted spring tubes are provided in the thesis entitled MODELING OF CANTED COIL SPRINGS AND KNITTED SPRING TUBES AS HIGH TEMPERATURE SEAL PRELOAD DEVICES by Jay J. Oswald submitted in May 2005.
Referring now to
By way of example and not of limitation, the cam inner surfaces 30a, 30b and 30c are equidistant from each other so the arcs occupied by the cams are each approximately 120°. The three-lobed cam inner surfaces 30a, 30b and 30c are configured to interface with a cage, which interfaces with a stud. Each lobe has a lobe centerline such as lobe centerline 31. Additionally, each lobe has a counterclockwise cam inner surface 32 on one side of the lobe centerline, and a clockwise cam inner surface 33 on the opposite side of the lobe centerline.
The illustrative lobe centerlines are 120° apart from each other. The illustrative counterclockwise cam inner surface 32 has a 60° arc, and the clockwise cam inner surface 33 also has a 60° arc. The illustrative counterclockwise cam inner surface 32 has a clockwise cam inner surface 33a and 33b on each side. Additionally, each clockwise cam inner surface 33 has a counterclockwise cam inner face 32 adjacent to the clockwise cam inner surface 33. Each lobe has a distal portion 35 along the lobe centerline that is furthest from the center of the housing.
In the embodiment presented in
In the illustrative embodiment of
Generally, a counterclockwise force (to loosen stud) is applied to the housing 20 for stud removal, this counterclockwise force is transferred to the cage 40, when the cage interfaces with the counterclockwise cam inner surface 32. There may be instances when stud removal requires the application of a clockwise force (tightening the stud) so the housing 20 is turned in a clockwise direction and this force is then transferred to the cage 40 with the clockwise cam inner surface 33. An illustrative impact wrench may be employed that has an operator controlled switch that can switch the direction of the force applied to the stud removal tool from counterclockwise, to clockwise, and back to counterclockwise. By performing this operation of oscillating between the counterclockwise and clockwise directions, additional torque may be transferred to more effectively remove the stud.
The illustrative three-lobed cam inner surface 30 is symmetrical and is presented for illustrative purposes only. Alternatively, other symmetrical lobed cam assemblies may also be used such as a two-lobed cam, a four-lobed cam, five-lobed cam, etc. The number of lobes and configuration of each lobe will depend on the particular application.
Additionally, each lobe may have more than just two symmetrical cam surfaces (i.e. clockwise inner cam surface and counterclockwise inner cam surface). For example, each lobe may have three, four, five or six different cam inner surfaces that can interface with different cages or cartridges.
Furthermore, asymmetrical cam inner surfaces may also be employed. Thus, the lobed cam inner surface may have additional surfaces beyond just the symmetrical three-lobed cam surface presented herein. The inner cam surface may be asymmetrical and include a plurality of surfaces that can interface with a plurality of different cages.
Referring now to
The illustrative rotary power tool may be an impact wrench (not shown) having an anvil (not shown) configured to be received by a polygon shaped opening 92 at the bottom end 22 of the stud tool 10. Although the opening is shown as being square shaped, a circular or elliptical shaped opening may also be configured to match the shape of the rotary power tool.
An impact wrench is a power tool that delivers a high torque output by storing energy in a rotating mass and then delivering the energy to the output shaft. The power source for an impact wrench is generally compressed air. When a hammer, i.e. rotating mass, is accelerated by the power source and then connected to an anvil, i.e. output shaft, this creates the high-torque impact. When the hammer spins, the hammer's momentum is used to store kinetic energy that is then delivered to the anvil in a theoretically elastic collision having a very short impact force.
With an impact wrench, the only reaction force applied to the body of the tool is the motor accelerating the hammer, and thus the operator feels very little torque, even though a very high peak torque is delivered to the anvil. The impact wrench delivers rotational forces that can be switched between counterclockwise rotation and clockwise rotation. Additionally, impact wrenches deliver oscillating compressive forces along the axis of the anvil of the impact wrench. Thus, when removing a stud, the anvil of the impact wrench is along a vertical axis and the impact wrench delivers oscillating compressive forces along the axis of the anvil, i.e. axial load, and rotational forces.
For the embodiments described herein, very large impact wrenches are used. These very large impact wrenches can deliver several hundred thousand foot-pounds of torque and are usually suspended from a crane or lift, since the impact wrenches are too heavy for a person to lift. Alternatively, other power tools besides impact wrenches are used to deliver high impact torque for stud removal, such as a regular drill or other such power tool.
Referring to
The illustrative canted coil spring 36 may have the coils canted in either a clockwise or counterclockwise depending on the particular application and design constraints.
Referring to
The illustrative elastic webbing 112 holds the jaws 106 symmetrically apart, retaining the jaws 106 firmly against the cam inner surface 30. The illustrative webbing 112a joins jaws 106a and 106b. Also, elastic webbing 112b joins jaws 106b and 106c. Additionally, webbing 112c joins jaws 106a and 106c. The webbing may also be embodied as an injection molded elastomeric cartridge or cage. By way of example and not of limitation, the bottom portion 107 of the cartridge is a steel ring that is fixedly coupled to the webbing 112.
By way of example and not of limitation the elastomeric component configured to join the jaws has a durometer ranging from 20-40. In a narrower embodiment, the elastomeric material has a durometer of 30. Generally, the webbing material is composed of an elastic material that can withstand operating conditions for stud removal. For example, the webbing matter may be composed of an elastic thermoplastic resin that is resistant to petroleum products. Also, other elastic or elastomeric materials such as rubber or neoprene may also be used.
In
Each jaw outer cam surface occupies a 60° arc. The jaw outer cam surface 108 or 138 is configured to interface with the cam inner surface 30 corresponding to the interior sidewall 29. The inner frictional surface 110 or 140 grips the stud. The inner frictional surface 110 or 140 may be ridge shaped or pyramid shaped, or any other such shape that can effectively grip the stud.
Referring to
Referring now to
When a counterclockwise force is applied to the housing that results in the housing shifting approximately 30° to the left and the jaws are biased radially inwards by the cam. The housing 20 is rotated by a rotary power source, such as the air impact wrench described above and the jaw outer cam surfaces 138a, 138b and 138c are configured to engage with the counterclockwise cam interface when a counterclockwise force is applied to the housing. When the jaws are biased radially inwards by the cam and the effective circumference of the cartridge is reduced, this causes the elastic webbing to flex (not shown). When the jaws are biased radially inwards, the inner frictional surface engages the stud.
More specifically, the stud removal tool is configured to turn in a counterclockwise manner. This rotation causes the cam inner surfaces 30a, 30b and 30c of the housing 20 to apply force to the cam outer surfaces 138 of the cartridge 40 containing the jaws 136a, 136b and 136c. The jaws 136a, 136b and 136c then rotate in a counterclockwise direction. In operation, the deformation of the elastomer upon the application of torque allows for the inner frictional gripping surface 140 of the jaws 136 to contact the stud 113 at multiple contact points.
Additionally, the jaw outer cam surface is configured to engage with the clockwise cam interface when a clockwise force is applied to the housing. During stud removal, the operator may increase the amount torque applied to the stud by toggling between applying a counterclockwise force and a clockwise force using the stud removal assembly described herein.
Referring now to
Referring to
The stud removal tool may have to remove very large studs, e.g. a stud weighing two hundred pounds, and so the retaining ring 60 may be used in conjunction with the canted coil spring 36 to rotatably couple the housing 20 to the cage 40. Although a properly designed canted coil spring can be used to rotatably engage the cage to the housing, the maintenance of the stud removal tool would be quite challenging. The maintenance challenge is removing a heavy-duty canted coil spring that can lift a heavy stud, e.g. 200 lbs., and a cage 40. For the illustrative 200 lb stud, the expected canted coil spring would need to support an axial load of 300 lbs. and a 300 lbs. spring would be difficult for an operator to remove. A retaining ring 60 can be used to reduce the axial load on the canted coil spring and so for very large studs, the operator that would be performing maintenance on the stud removal tool could, first, remove the retaining ring 60 that provides some axial support, second, remove the cage 40, and then remove the canted coil spring 36 that provides additional axial support.
Alternatively, the stud removal apparatus described above may not require a canted coil spring or other such seal preload device. Thus, the illustrative canted coil spring may simply be replaced with a retaining ring 60 described above. In addition to retaining ring 60 other fastening means may also be used.
For example, in
It is to be understood that the detailed description of illustrative embodiments provided for illustrative purposes. The scope of the claims is not limited to these specific embodiments or examples. Various structural limitations, elements, details, and uses can differ from those just described, or be expanded on or implemented using technologies not yet commercially viable, and yet still be within the inventive concepts of the present disclosure. The scope of the invention is determined by the following claims and their legal equivalents.
| Number | Name | Date | Kind |
|---|---|---|---|
| 1294171 | Rockwell | Feb 1919 | A |
| 1740377 | Snyder et al. | Dec 1929 | A |
| 2027534 | Ingersoll | Jan 1936 | A |
| 2069527 | Kirkland | Feb 1937 | A |
| 2550929 | Keiser | May 1951 | A |
| 4222688 | LeMay | Sep 1980 | A |
| 4235134 | McLendon | Nov 1980 | A |
| 4604917 | Polonsky | Aug 1986 | A |
| 4651596 | Rachanski | Mar 1987 | A |
| 4724730 | Mader et al. | Feb 1988 | A |
| 4972742 | Brown | Nov 1990 | A |
| 5251515 | Merrick | Oct 1993 | A |
| 5299473 | Weber et al. | Apr 1994 | A |
| 5315902 | Ragland et al. | May 1994 | A |
| 5349887 | Suwa | Sep 1994 | A |
| 5533426 | Morales | Jul 1996 | A |
| 5638909 | Henderson | Jun 1997 | A |
| 5690004 | Weber et al. | Nov 1997 | A |
| 5799560 | Meng | Sep 1998 | A |
| 5904076 | Siwy | May 1999 | A |
| 5906146 | Arlen | May 1999 | A |
| 6073520 | Bueno et al. | Jun 2000 | A |
| 6099311 | Wagner et al. | Aug 2000 | A |
| 6536309 | Pool | Mar 2003 | B1 |
| 6807880 | Brian et al. | Oct 2004 | B1 |
| 6877401 | Giltner | Apr 2005 | B1 |
| 6988431 | DiStasio | Jan 2006 | B2 |
| 7140087 | Giltner | Nov 2006 | B1 |
| 7437975 | De Anfrasio | Oct 2008 | B1 |
| 20040187646 | Whitehead et al. | Sep 2004 | A1 |
| 20060150778 | Hennessey et al. | Jul 2006 | A1 |
| 20080016987 | Schultz | Jan 2008 | A1 |
| Number | Date | Country |
|---|---|---|
| 0216354 | Apr 1987 | EP |
| 2011104707 | Jun 2011 | JP |
| Entry |
|---|
| Baconsdozen, “Removing rusted, damaged or worn nuts and bolts.” Accessed Oct. 23, 2012. http://www.baconsdozen.co.uk/Rustynuts.htm. |
| alltiresupply.com. Grey 1/2″ Drive Damaged Nut Remover (#6) (GP-2306NR). Accessed Oct. 23, 2012. http://www.alltiresupply.com/p-GP-2306NR.html. |
| USABlueBook,com. 10-Pc Damaged Bolt/Nut Remoner Set (Craftsman No. 9-52165). Accessed Oct. 23, 2012. http://www.usabluebook.com/p-289783-10-pc-damaged-boltbut-remover-set-craftsman-no-9-52165.aspx. |
| MechanicsToolSupply.com, “Damaged Lug Nut Removal Tool AP7401.” Accessed Oct. 23, 2012. http://mechanicstoolsupply.com/Damaged-Lug-Nut-Removal-Tool-AP7401—p—24114.html. |
| NorthernGunParts.com. AR15/M16 Barrel Extension Nut Removal Tool. Accessed Oct. 23, 2012. http://www.northerngunparts.com/ar15m16barrelextensionnutremovaltookaspx. |
| SearsPartsDirect.com. Bolt-out 5-Piece Damaged Bolt/Nut Remover Set. Accessed Oct. 23, 2012. http://www. searspartsdirect.com/partsdirectipart-number/52061/0009/009&pathTaken=partSearch&blt=14&prst=0&shdPart=52061. |
| OReillyAutoParts.com. Xtra Seal—Dual Sided Twist Socket Lug Nut Remover. Accessed Oct. 25, 2012. http://www.oreillyauto.com/site/c/detail/XTS0/14840.oap?ck=Search—lug+nut+remover—-1—-1&keyword=lug+nut+remover. |
| TheToolWarehouse.Net. Damaged Lug Nut Removal Tool. Accessed Oct. 26, 2012. http://www.thetoolwarehouse. net/p-18405-damaged-lug-nut-removal-tool-18mm-and-195mm-flip-socketaspx. |
| Oswald, Jay Joseph. “Modeling of Canted Coil Springs and Knitted Spring Tubes as High Temperature Seal Preload Devices,” Case Western Reserve University, May 2005. |
| International Search Report with Written Opinion issued in related PCT Application No. PCT/US2014/016459, dated May 20, 2014, 9 pages. |
| Number | Date | Country | |
|---|---|---|---|
| 20140224076 A1 | Aug 2014 | US |
