STUD INSTALLER

Abstract: A stud insertion and mounting device with a threaded bore formed axially through a tubular body. The bore has an open end and a closed end in which an abutting and locking means is positioned at the closed end to abut the stud for rotatably threading said stud into a suitably tapped receiving hole. A means for releasing the abutting and locking means from the mounted stud is provided, upon which when the device is rotated, the device is unthreaded from the mounted stud. The abutting and locking means may be a cylinder with a chamfered end or other shape. The device may be rotatably driven by a conventional pneumatic source or by hand through a conventional socket or open-ended wrench.

Description: The present invention relates generally to a device for inserting and mounting of headless bolts or studs and the like in mechanical devices. Many engines, transmissions and other mechanical devices use headless bolts or studs for assembly of related components. As used herein, the term "stud" or "headless bolt" refers generally to a shaft having screw threads formed along part or all of its entire length. When assembling components of an engine during production or after repair, studs must be installed without damaging the threads. The insertion of these studs is often a difficult, tedious and very expensive task. One makeshift method commonly used is to "double nut" a stud by threading two nuts onto the stud to be inserted, and tightening each nut against the other in opposite directions until they abut and fixedly lock onto the stud. The assembled double nut and stud combination then is inserted into the required mechanical device using the double nuts as a means for driving the assembled combination. After the stud is mounted, the nuts must be loosened by rotating each in opposite directions and then backed off from the mounted stud. This cumbersome and time consuming method is eliminated by forms of stud insertion tools. However, in the past many stud driving and insertion tools were complex, either requiring many individual pieces, or were of a design which required considerable amount of effort and physical manipulation in mounting the headless bolt or stud into the associated mechanical device. Many of these tools were very expensive to manufacture because of the large number of intricacy of the individual components. Previous stud installing tools required use of an independent locking device such as a pin or set screw to first lock the stud into the tool before installation of the stud into the associated member. When these forms of prior devices are utilized, the stud, after being driven and mounted into the desired location, must then be unlocked and the tool backed off from the stud while taking care not to loosen the stud from its mounted location. Other prior stud-mounting tools utilize locking rings or collars with threaded pitches different than the pitch of the stud. This difference would cause the ring or collar to "jam" onto the stud and thereby, catch and engage the stud. After insertion, the device must be reversed to "un-jam" and remove the device from the mounted stud, and, because of the difference in thread pitch, excessive wear of the stud threads was created. For example, U. S. Patent No. l,438,269 utilizes a sleeve threaded at one end to receive a stud, and the sleeve also is threaded at the other end to receive a cap screw. The cap screw has a greater pitch than the stud. A pin is driven radially through the shaft of the cap screw. Lugs are mounted to the top of the sleeve to enable the sleeve to be rotated when the cap screw is turned to bring the pins into contact with the lugs. U. S. Patent No. 3,292,463 utilizes a bushing having external multiple threads which are threaded to receive the bushing in a blind hole, and an internal thread to receive the stud. Resilient O-rings are used to bind and help resist binding upon release of the stud during removal of the stud from the tool once the stud is mounted. U.S. Patent No. 2,521,910 utilizes a sleeve with an internally threaded bore formed with three arcuate evenly spaced corroborating die cutting teeth, the same being separated by slots or notches extending the full length of the tool, whereby a headless bot1t or screw is threaded by hand into the threaded bore. A pin is radially inserted through selected holes in the sleeve to contact the stud. After the stud is driven, the pin is removed, thus releasing the stud. U.S. Patent No. 2,746,328 utilizes a locking pin that is threaded through the cylindrical wall of the tool to lock a jaw set against the stud. Document FR-A-346,351 shows in figures 3 and 4 a stud installer in which an elongate nut has opposing coaxial threaded bores. One bore is used to receive the stud to be installed while the other bore, which may be smaller, receives a screw. The screw is locked against rotation by a pin. The end of the screw projects into the bore for receiving the stud and in use abuts the end of the stud. With the installer of FR-A-346,351 there is a danger that an installed stud wil not be as tight as indicated on a torque wrench use to turn the stud installer. It has been found that this is due to a sideways skewing of the screw when under load. Moreover the resilence in the screw tends to inhibit detachment of the screw from the top of the stud as the stud installer is unscrewed from an installed stud. Easy detachment is important at that time to prevent loosening of an installed stud. The object of the present invention is to provide a stud installing tool to install studs reliably and then release itself with a minimal amount of additional motion and effort and without the risk of loosening the stud. The present invention provides a device for inserting and mounting a stud, said device comprising an elongate tubular member having a first end and a second end; said first end having a coupling means for driving said device; said second end having a threaded hole bored within said tubular member; a projection extending from the end of said threaded hole to meet and abut said stud, said projection being of lesser abutting surface area than the abutting end of said stud; characterized by said threaded hole extending within said tubular member only partially the length of said tubular member; said projection abutting the stud being formed as part of the tubular member at the end of the threaded hole. Optional features of the invention are set out in claims 2 to 4 below. The present invention provides many advantages over previous stud installation tools in that it allows for easy insertion of a stud into the tool, then easily mounts the stud into the stud receiving member, after which, upon a single action of reverse rotation, allows the mounted stud to be loosened from the tool without appreciably loosening the already mounted stud from the stud receiving member, thus allowing the tool to be very quickly backed off from the mounted stud. An additional advantage is that the present invention is very compact in design, allowing the tool to be used in tight places where many other tools would require greater clearance to operate. Numerous other advantages of the invention will become readily apparent from the following detailed description of a preferred embodiment of the invention taken together with the accompanying drawings wherein: Figure l is a perspective view of the stud insertion device of the present invention; Figure 2 is a lateral view of the present invention in partial cross-section of the stud insertion tool with a stud engaged within the tool and being partially mounted into an associated stud receiving member; Figure 3 is a lateral view in full cross-section of the stud insertion tool shown in Fig. l but with no stud in position; Figure 4 is a top plan view of the stud insertion tool showing its female socket driving end; and Figure 5 is a bottom plan view of the stud driving end of the stud insertion tool showing the chamfered cylindrical end projecting from the end of stud insertion hole. While this invention is susceptible of embodiment in many different forms, there is shown in the drawings and will herein be described in detail a preferred embodiment of the invention. Referring now to Figures l and 2, the numeral 20 refers generally to a stud insertion tool constructed in accordance with the present invention. A stud l5 is depicted in Figure 2, in which stud driving end l6 is engaged and locked into cylindrical stud holder 2l, and with the stud mounted end l7 beung partially mounted into an associated stud receiving member 30. The holder 2l comprises an elongated tubular member having a closed end 22 and an open end 25. The closed end 22 is provided with a driving hexagonally-shaped head 23. The open end 25 is formed to provide an axially threaded internal bore 26.A chamfered end projection 28 projects centrally from the closed end of threaded bore 26 toward open end 25. The protrusion 28 is provided to meet and abut the stud l5 and to releasably lock thereto in a manner described hereinbelow. This protrusion 28 may be configured in many different shapes, but preferably may be an arcuate projection or cylindrically shaped projection with a chamfered end. Alternatively, a conical as well as an angularly cylindrical protrusion may be employed. Figure 3 is a cross-sectional side view of the cylindrical stud holder 2l showing first end 22, second end 25, threaded bore 26, head 23, and additionally depicting female drive socket means 24. Figure 4 is a top view of cylindrical stud holder 2l showing first end 22, head 23 and female socket means 24. Figure 5 is an end view of second end 25 into which a stud l5 (shown in Figure 2) may be inserted into the threaded bore 26 and abut projection 28. The operation of the present invention is simply and effectively described as follows. A stud l5 is selected for mounting into a required location such as depicted in Figure l as stud receiving member 30. Stud l5 is threaded into the second end 25 of cylindrical stud holder 2l via the threaded bore 26. Stud l5 is threaded until stud driving end l6 of stud l5 meets and abuts chamfered end projection 28. Stud l5 is threaded until reaching finger tightness or the required torque level to keep stud l5 frictionally and fixedly held against projection 28. Cylindrical stud holder 2l is thereby driven by means of applying a rotatable force at the first end 22 either via head 23 or female drive socket means 24, to firmly seat stud l5 into the stud receiving member 30 as depicted in Figure l. After cylindrical stud holder 2l has completely mounted stud l5 into the stud receiving member 30, holder 2l is rotated in a reverse direction either via hexagonally-shaped head 23 or female drive socket means 24 leaving stud l5 held fixedly in place in the stud receiving member 30 while holder 2l releasably unthreads itself from the threaded bore 26 and is no longer in contact with stud l5 at projection 28. The reverse rotational motion is continued until holder 2l is removed from stud l5 and is no longer in contact with the threaded bore 26. Cylindrical stud holder 2l allows studs to be mounted in a simple manner by threading and fixedly locking a stud l5 into holder 2l within the threaded bore 26 and abutting against chamfered end projection 28 which is configured in such a way as to hold and frictionally affix stud l5 for driving but readily releases the stud l5 after the stud l5 is mounted in the stud receiving member 30 without loosening the mounted stud l5. The present invention allows studs to be mounted in the above described fashion because of the following principles. The stud is firmly locked and abutted into the tool by the frictional force created between the projection and the tool abutting end of the stud. When the stud is mounted into the desired location by the use of the tool embodying the present invention, the stud mounting end "bottoms out" or frictionally binds itself against the bottom or end of the threaded receiving hole. Whereby, when removing the tool from the mounted stud, by rotating the tool in a reverse direction, a lesser frictional force is required to loosen the stud from the tool than the stud from the receiving hole. The force needed to release the stud from the tool is less because the abutting surface area between the projection and the stud is less than the abutting surface area between the stud and the bottom of the receiving hole. The surface area between the projection and the stud must be less than the entire surface area of the tool abutting end of the stud for the tool to release the mounted stud without loosening the stud from the receiving hole.

Claims: A device for inserting and mounting a stud, said device comprising an elongate tubular member (21) having a first end (22) and a second end (25); said first end (22) having a coupling means (23) for driving said device; said second end (25) having a threaded hold (26) bored within said tubular member; a projection (28) extending from the said threaded hole to meet and abut said stud, said projetion being of lesser abutting surface area than the abutting end of said stud; characterized by said threaded hole (26) extending within said tubular member (21) only partially the length of said tubular member; said projection (28) abutting the stud being formed as part of the tubular member (21) at the end of the threaded hole (26). A device of claim 1 characterized in that the projection (28) is a cylinder with chamfered end. The device of claim 1 or 2, characterized in that the projection (28) has a lower generally flat faced portion directed toward the open end of said bore. The device of claim 1, 2 or 3, characterized by means of driving said elongated tubular member of a conventional pneumatic or other rotatably driven power source.

Inventors: RACHANSKI, EDWARD J, JR., RACHANSKI, MICHAEL A.
Applicants: EEM RACHANSKI ENTERPRISES, INC.
Application year: 1986
Main classification: B25B23
IPC codes: B25B13, B25B27, B25B21, B25B23