Tools – Wrench – screwdriver – or driver therefor – Stud-removal and implacement
Reexamination Certificate
1992-09-14
2001-02-20
Smith, James G. (Department: 3723)
Tools
Wrench, screwdriver, or driver therefor
Stud-removal and implacement
C411S321000
Reexamination Certificate
active
06189416
ABSTRACT:
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'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.
REFERENCES:
patent: 692988 (1902-02-01), Davis
patent: 751345 (1904-02-01), Saunders
patent: 846593 (1907-03-01), Minne
patent: 1134596 (1915-04-01), Dillon
patent: 1183556 (1916-05-01), Green
patent: 1317332 (1919-09-01), Stark
patent: 1740377 (1929-12-01), Snyder et al.
patent: 2795159 (1957-06-01), Sine
patent: 3718058 (1973-02-01), Jones, Jr.
patent: 4619568 (1986-10-01), Carstensen
patent: 4620460 (1986-11-01), Gonzales, Jr.
patent: 4880343 (1989-11-01), Matsumoto
patent: 4977799 (1990-12-01), Yasutomi et al.
patent: 0835790 (1938-12-01), None
Pravel, Hewitt, Kimball & Krieger, P.C.
Smith James G.
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