Abstract:
A stud bolt tool and method for using the stud bolt tool to install or remove a threaded stud bolt from a threaded blind bore. The stud bolt tool has a cylindrical housing having a first and second surface and an internally threaded bore communicating with the first and second surfaces. The housing includes a plurality of circumferentially spaced ports surrounding the internally threaded bore. The ports communicate with the first and second surfaces of the cylindrical housing and each port has a threaded portion extending to the second surface. A plurality of balls are slidably stacked in each port. The ball nearest the first surface is capable of partially protruding beyond the first surface and is also capable of retracting within the port below the first housing surface. A screw threadably engages each threaded portion of each port. Advancement of the screw into the port forces the ball to partially protrude beyond the first surface.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a tool for use in installing or removing stud bolts. 
     2. Description of the Prior Art 
     Threaded stud bolts are used in a variety of applications. Typically, the stud bolts, designated generally as B, are installed in an internally threaded counter bore or blind bore A as shown in FIGS. 1 and 2. The stud bolts B are threaded along their entire length and have no surfaces for utilizing a wrench to rotate the stud bolt B and thereby threadably engage the stud bolt B with the threaded blind bore A. 
     FIGS. 1 and 2 disclose two known methods for screwing a stud bolt B into the threaded blind bore A. FIG. 1 illustrates one method in which a box nut  10  is screwed on top of the stud bolt B and a torque wrench (not shown) engages the box nut  10  to rotate it together with the stud bolt B. In FIG. 2, two nuts  12  and  14  are screwed onto the stud bolt B and the nut  14  is rotated so as to tighten the nut  14  against the nut  12  which interlocks the two nuts  12 ,  14 . The nut  14  is then rotated with a torque wrench which also rotates the stud bolt B. In either of the methods shown in FIGS. 1 and 2, it is necessary to apply a force substantially equal to the force required to tighten the box nut  10  to the stud bolt B or the nuts  12 ,  14  to the stud bolt B in order to loosen and remove the nuts. Removing the cap nut  10  requires use of a torque wrench to loosen the cap nut  10  from the end of the stud bolt B without loosening the stud bolt B from the blind bore A. The stud bolt B cannot be gripped by the threads for fear of damaging the threads. In FIG. 2, the flat side surfaces  16  of the two nuts  12 ,  14  must be aligned at high torque to enable use of an impact wrench and socket. If an impact wrench and socket is used to loosen the nut  14 , the operator&#39;s safety will be jeopardized. Thus, this second method typically requires a two tool operation in which the lower nut  12  is held with a wrench while the upper nut  14  is reversibly rotated to free the interlocked nuts. Oftentimes, it is extremely difficult to free the interlocked nuts  12 ,  14  and it is required to be performed in dangerous environments, as for example, from catwalks, scaffolding, etc. In such circumstances, the sudden breaking loose of one nut under high torque could throw the operator off balance causing the operator to fall from scaffolding, etc. 
     The second method of using two nuts  12 ,  14  may also be used to remove the stud bolt B. In the removal operation, a torque wrench is applied to the lower nut  12  and torque is applied in the appropriate direction. Typically, the flat surfaces  16  of the nuts  12  and  14  are not aligned with the nuts are interlocked. Thus, since this is generally the case, in impact wrench with socket cannot be used to rotate the lower nut  12  when removing the stud bolt B. Once the stud bolt B has been removed, a two tool operation is again required to remove the interlocked nuts  12 ,  14 . The stud bolt B is not anchored at this point and removing the nuts  12 ,  14  is a dangerous operation. One alternative is to take the removed stud bolt B with the interlocked nuts  12 ,  14  to the machine shop and place one nut in a vise to hold that nut stationary while the second nut may be reversibly rotated with a wrench. However, oftentimes a vise is not available in the field to break loose or free the interlocked nuts  12 ,  14 . 
     U.S. Pat. No. 4,977,799 discloses a clamping tool for use with a stud bolt. The clamping tool includes a torque transmission mechanism such that the torque necessary to loosen the clamping tool to detach it from the stud bolt tightened in position is much smaller than the torque necessary to tighten the stud bolt. This clamping tool is a complex tool which is expensive to fabricate and which cannot be used to remove a tightened stud bolt from a blind bore. 
     It is highly desirable to have a tool for stud bolt removal and installation operations which is of simple construction, low cost manufacture, and which is readily mountable to the stud bolt for operation or dismountable from the stud bolt after operation by a single operator in the field with safety. 
     SUMMARY OF THE PRESENT INVENTION 
     The present invention is a tool for stud bolt removal and installation operations which is simple to use, convenient, easy to manufacture, and extremely safe to use. 
     The stud bolt tool has a cylindrical body or housing having a first and second surface and an internally threaded bore communicating with the first and second surfaces. A plurality of circumferentially spaced ports surround the internally threaded bore in the housing. The ports communicate with the first and second surfaces of the housing. Each of the ports has a threaded portion which extends towards the second surface. A plurality of ball bearings are slidably stacked in each port. The ball bearing nearest the first surface is capable of partially protruding beyond the first surface to bear against a nut positioned on the stud bolt and is also capable of retracting within the port below the first surface. A screw threadably engages the threaded portion of the port. As the screw is advanced into the port, it forces the opposite ball bearing to partially protrude beyond the first surface. When the screw is partially unthreaded from the port, the ball bearing is allowed to fully retract within the port below the first surface. 
     In use, the stud bolt tool and a nut are threaded onto a stud bolt. The first surface of the stud bolt tool is brought into contact with the nut. The screws have been positioned such that the ball bearings are not forced to protrude beyond the first surface of the tool body but are fully retractable within the port. With the first surface of the stud bolt tool contacting the nut on the stud bolt, the screws are threadably advanced in each of the ports to force the ball bearing to partially protrude beyond the first surface until it is in firm engagement with the nut. A torque wrench is applied to the nut and torque is applied in the direction to rotate the nut towards the stud bolt tool which is now interlocked with the nut. As the nut rotates, the stud bolt tool and the stud bolt also rotates. After the stud bolt has been positioned as desired (installed or removed) the screws of the stud bolt tool are threadably reversed in each of the ports to allow the ball bearing to retract therein to disengage them from contact with the nut, and the stud bolt tool and nut may readily be removed from the stud bolt by hand torquing. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In order to more fully understand the drawings referred to in the detailed description of the present invention, a brief description of each drawing is presented, in which: 
     FIG. 1 is an elevation view of partial cross-section of a stud bolt partially installed in a blind bore with a closed end box nut; 
     FIG. 2 is an elevation view in partial cross-section of a stud bolt partially installed in a blind bore with interlocking double nuts; 
     FIG. 3 is an elevation view in partial cross-section of a stud bolt being installed in a bore with a nut and the stud bolt tool of the present invention; 
     FIG. 4 is a view taken along line  4 — 4  of FIG. 3; 
     FIG. 5 is an exploded view of the stud bolt tool; 
     FIG. 6 is a cross-sectional view taken along line  6 — 6  of FIG. 4; 
     FIG. 7A,  7 B, and  7 C are top views of alternate embodiments of the stud bolt tool having varying numbers of circumferentially spaced ports for locking the stud bolt tool; and 
     FIG. 8 is an elevation view in partial cross-section of a stud bolt being removed from a blind bore with a nut and the stud bolt tool of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to FIG. 2, it can be seen that when the two nuts  12  and  14  are tightened against one another on the stud bolt B, a small gap, designated generally as G, exists between a portion of the opposing surfaces  13  and  15  of the nuts  12  and  14 , respectively. Because of the stud bolt threads, the top and bottom surfaces of a nut are not perfectly square to the axis of the stud bolt B. However, when the nuts  12 ,  14  are interlocked on the stud bolt B, commonly referred to as “double-nutted,” the interlocked nuts contact and frictionally engage one another and the nuts&#39; threads and the stud bolt threads are frictionally engaged which results in frictionally locking the two nuts against rotation relative to the stud bolt. 
     Referring to FIG. 5, the stud bolt tool, designated generally as  100 , is shown in exploded view. The tool  100  includes a tool housing or body  20  having a substantially planar second surface  22  and a substantially planar second surface  24  in opposing relationship to the first surface  22 . The tool body  20  includes an internally threaded through bore  26  communicating with the first and second body surfaces  22  and  24  respectively. The diameter and threading of the internally threaded bore  26  corresponds with the diameter of the threaded stud bolt B onto which it will be screwed. The tool body  20  further includes a plurality of ports  28  which are circumferentially spaced around the internally threaded bore  26 . The ports  28  communicate with the first and second surfaces  22 ,  24 , respectively, of the tool body  20 . As shown in FIGS. 3 and 6, the ports  28  includes a first portion  30  having a smooth, cylindrical bore and a second portion  32  which includes a threaded cylindrical bore. In the preferred embodiment, a plurality of ball bearings  34  sized to fit in the port  28  are assembled in the port  28 . As shown in FIGS. 3,  5  and  6 , three ball bearings  34  are stacked in each port  28 , although it is possible to use more or fewer ball bearings  34  in each port  28 . Preferably, each port  28  contains two or three ball bearings  34 . However, even a single ball bearing  34  may be used. 
     The diameter of the ball bearings  34  are sized approximately to the diameter of the first portion  30  of the port  28 . This ensures that the stack of ball bearings  34  remain in a linear relationship while in the port  28 . It is, however, important that the ball bearings  34  are free to slide longitudinally within the port  28 . Preferably, the diameter of the first portion  30  of the port  28  is approximately 0.002″ to 0.003″ greater than the diameter of the ball bearing  34 . 
     As shown in FIG. 6, a lip or stopping means  36  is provided at the interface of the port  28  with the first surface  22  of the tool body  20 . The stopping means  36  prevents the ball bearings  34  from exiting the port  28  at the first surface  22 . The stopping means  36  may consist of any of several known ways of restricting the travel of a ball bearing in a cylindrical port. By way of example, the lip or stopping means  36  could be a reduced diameter bore at the interface with the first surface  22  and could be formed by punching or deforming the circumference of the port  28  at the first surface  22 . 
     Referring to FIGS. 5 and 6, a screw  38  is threaded into the second portion  32  of each port  28 . The screw  38  is preferably an allen screw having a countersunk hexagonal head for which an allen wrench (not shown) is used to rotate the allen screw  38 . Other types of set screws may be used, but it has been found preferable to use an allen screw due to the space limitations and ease of manipulating the allen screws with an allen wrench. 
     As shown in FIG. 5, there are four ports  28  circumferentially spaced around the threaded bore  26 . Preferably, at a minimum there should be at least three ports  28  circumferentially spaced around the internal threaded bore  26  as shown in FIG.  7 A. However, it may be desirable to have five, or even six ports  28  spaced around the bore  26  as shown in FIGS. 7B and 7C, respectively. The number of bores  28  desired may vary depending on the diameter of the internal threaded bore  26 . 
     In the preferred embodiment, the tool body  20  has a cylindrical outer surface  40  as shown in FIGS. 4,  5 ,  7 A,  7 B, and  7 C. Preferably, the outer diameter D 1  of the tool body  20  is less than the distance D between opposing flat side surfaces  16  of a nut  50 , as shown in FIG. 4, for reasons which will be explained below. It is to be understood that the nut  50  is a standard hexagonal nut. The outer surface  40  may be knurled (See FIGS. 3,  5 , and  8 ) to provide a good gripping surface for handling the tool  100 . 
     It should be further understood that a separate stud bolt tool  100  is required for each diameter of stud bolt B. Additionally, it is necessary that the threads of the internally threaded bore  26  correspond with the threads of the stud bolt B. 
     The operation of using the stud bolt tool  100  of the present invention will now be described. Firstly, referring to FIG. 3, the operation of installing a stud bolt B with the tool  100  will be described in detail. The screws  38  are threadably adjusted in the ports  28  so that the ball bearing  34  nearest the first surface  22  and farthest from the screw  38  is positioned at or slightly below the plane of the first surface  22 , as shown by solid lines in FIG.  6 . The tool  100  is threaded onto the stud bolt B with the threads of the stud bolt B mating the internally threaded bore  26  of the tool body  20 . It is important that the tool  100  is threaded onto the stud bolt B in a manner such that the first surface  22  of the tool body  20  faces the regular nut  50  which is next threaded onto the end of the stud bolt B, as shown in FIG.  3 . The tool  100  is threaded onto the stud bolt B a distance sufficient to permit the regular nut  50  to also be threaded onto the end of the stud bolt B. 
     The nut  50  is threaded by hand onto the stud bolt B until the nut  50  contacts the first surface  22  of the tool  100 . The operator takes the allen wrench and screws the allen screws  38  further into the threaded portion  32  of the ports  28  until all the stacks of ball bearings  34  make firm contact with the nut  50 , thus interlocking the tool  100  with the nut  50 , as shown in FIG.  3 . The engagement of the ball bearings  34  against the nut  50  causes the threads of the tool  100  and the nut  50  to frictionally engage the threads of the stud bolt B. The circumferential spacing of the ports  28  permits frictional engagement of the threads uniformly around the periphery of the stud bolt B. Thus, for larger diameter stud bolts such as 1½″ to 2″ stud bolts, it may be desirable to include more ports  28 , as shown in FIGS. 7B and 7C, to ensure uniform frictional engagement with the stud bolt B. This is more important in the removal operation of a stud bolt B due to the higher forces required to free a stud bolt B from the bore A. The individual allen screws  38  in each port  28  allows independent engagement of each stack of ball bearings  34  with the nut  50  irrespective of the gap G existing between the first surface  22  of the tool  100  and the nut  50 . 
     It should be understood that the amount of the gap G that can be taken up by the ball bearings  34  is limited to less than ½ the diameter of the ball bearing  34  due to the stopping means  36  preventing the dislocation of the ball bearing  34  from the port  28 . The gap G that exists when the tool  100  and the nut  50  are brought into contact will vary depending on the size of the stud bolt B. The larger the stud bolt B, the larger the gap G that may exist. Thus, larger diameter ball bearings  34  will be required in the stud bolt tools  100  for the larger stud bolts. However, for the stud bolt tools  100  for the smaller diameter stud bolts B (for example, ½″ to 1″), smaller ball bearings  34  are required due to the space limitations imposed by distance D between the flat surfaces  16  of the nut  50  and the need to keep the outside diameter D 1  of the tool  100  less than the distance D. Thus, it has been found that ball bearings  34  having a diameter of ⅛″ to {fraction (5/32)}″ are suitable in stud bolt tools  100  in the range of ½″ to 1¼″ diameter stud bolts, whereas a {fraction (7/32)}″ diameter ball bearing may be required to accommodate 1½″ to 2″ diameter stud bolts. 
     The stud bolt B with the tool  100  and the nut  50  is now loosely threaded by hand into the blind bore A. A torque wrench (not shown) is applied to the nut  50  and the stud bolt B is tightened in the blind bore A. As can be seen in FIGS. 3 and 4, a socket (not shown) can be positioned over the nut  50  and extend over the stud bolt tool  100  without any interference by the stud bolt tool  100  due to its reduced diameter D 1 . Once the stud bolt B has been tightened, the operator removes the torque wrench and partially unthreads the allen screws  38  from the port  28  with the allen wrench so that the ball bearings  34  are once again slidably retractable in their initial position in the ports  28  and no longer in firm engagement with the nut  50 . The tool  100  and the nut  50  are no longer interlocked and the nut  50  and the tool  100  are removed with ease and may even be removed by hand. 
     Referring to FIG. 8, the operation of removing a stud bolt B with the tool  100  will now be described in detail. The nut  50  is installed on the stud bolt B. The stud bolt tool  100  is threaded onto the stud bolt B with the ball bearings  34  facing the nut  50 . The allen screws  38  are in their initial position such that the allen screws  38  are not forcing the ball bearings  34  beyond the first surface  22  of the tool body  20 . The tool body  20  is threaded onto the stud bolt B until the first surface  22  contacts the nut  50 . The operator then takes the allen wrench and screws the allen screws  38  further into the threaded portion  32  of the ports  28  until all the stacks of ball bearings  34  make firm contact with the nut  50 , thus interlocking the tool  100  with the nut  50 , as shown in FIG.  8 . 
     A torque wrench (not shown), such as an impact wrench and socket, is applied to the nut  50 . Due to the outer diameter D 1  of the stud bolt tool  100  being less than the distance between the flat surfaces  16  of the nut  50 , the socket can be positioned over the stud bolt tool  100  and then over the nut  50 . The operator then applies a torquing force to the nut  50  to unthread the stud bolt B from the blind bore A. Once the stud bolt B has been removed from the blind bore A, the operator removes the torque wrench and partially unthreads the allen screws  38  from the port  28  with the allen wrench so that the ball bearings  34  are no longer in firm engagement with the nut  50 . The stud bolt tool  100  and the nut  50  are no longer interlocked and the nut  50  and the stud bolt tool  100  are removed with ease from the stud bolt B. 
     In an alternative embodiment of the invention the means for interlocking the stud bolt tool  100  to a nut  50  may comprise a screw only wherein the screw is of a length greater than that of port  28 , and the tip of the screw preferably has a tapering point in the nature of a ball point. In this embodiment that ball point screw comprises a single element which forms the means for protruding beyond or retracting within the housing  20  of the tool  100  for interlocking or releasing from interlocking with a nut  50  for stud bolt B installation or removal from a blind bore A. 
     The foregoing disclosure and description of the invention is illustrative and explanatory thereof, and various changes in the size, shape, and materials, as well as in the details of illustrative construction and assembly, may be made without departing from the spirit of the invention.