Cutting by use of rotating axially moving tool – Processes – Bit detachable
Reexamination Certificate
2001-02-05
2003-05-06
Howell, Daniel W. (Department: 3722)
Cutting by use of rotating axially moving tool
Processes
Bit detachable
C408S07200R, C408S087000
Reexamination Certificate
active
06558088
ABSTRACT:
FIELD OF THE INVENTION
The present invention pertains to devices for gaining access to security containers, and more particularly to devices that can be used to cut a lock bolt of a security container.
BACKGROUND OF THE INVENTION
Various types of security containers are used for such purposes as storing confidential or sensitive documents, valuables, and the like. Typical of such security containers are secure filing cabinets having combination locks to prevent unauthorized access. Occasionally, it becomes necessary to gain access to such containers by use of force, such as by drilling the lock bolt, usually when the combination has been lost or when the lock mechanism has malfunctioned.
The use of a power drill to gain access to a locked security container is known in the art. U.S. Pat. No. 5,984,594 describes an apparatus and method for drilling a small hole near the lock mechanism to allow a locksmith to observe the inner workings of the lock. Drilling into the lock itself is generally undesirable due to the considerable expense involved in repairing or replacing the lock. Therefore, it is preferable to gain access to and cut the lock bolts of such a container. Typically, a carbide-tipped hole-saw is used to cut through a front surface of the container, such as the front surface of a drawer, and then through the lock bolts behind the front surface. Often these lock bolts are formed from one-inch diameter cylindrical rods of hardened steel. Because the lock bolts are generally supported only near their ends, they tend to bind against a hole-saw under the considerable pressure required to cut through them. This binding generates excessive heat and tool chatter which can damage the carbide tips of a hole-saw and makes cutting the bolts difficult.
Referring to
FIGS. 1 and 2
, the prior art method of cutting a lock bolt will now be described.
FIG. 1
shows a security container
10
, in the form of a secure filing cabinet, with access drawer
12
that can be secured in a closed position by a pair of lock bolts
14
and
16
. In a closed and locked state, ends
18
and
20
of lock bolts
14
and
16
engage apertures
19
and
21
in container
10
that are adapted to receive the lock bolts and prevent opening of the drawer. A combination dial
22
is used to actuate a locking mechanism
24
to provide an unlocked state, whereby lock bolts
14
and
16
may be retracted from the container apertures by actuation of a lever
26
, or alternatively by rotation of the dial
22
.
In the event that lock mechanism
24
has malfunctioned or the combination has been lost, entry into container
10
is often obtained by cutting lock bolts
14
and
16
using a carbide-tipped hole saw
28
. Typically, the hole-saw
28
is advanced through a front panel
29
of drawer
12
, creating panel hole
57
, and subsequently through lock bolt
14
by using a drill rig
30
. A typical drill rig used for such purposes is the MAG457100 Bullet Rig and L2021 Tower Assembly, available from Lockmasters, Inc. A drill plate
32
is fastened to drawer panel
29
in a location near lock bolt
14
using self-tapping screws
34
. Stand-offs
36
support a flanged mounting plate
38
secured by cap screws
40
. A first tube
42
has internal threads (not shown) and is slidably attached to the flanged mounting plate
38
by a quick-release locking collar
44
. Detents
46
on the first tube
42
engage the locking collar
44
to lock first tube
42
in place at various positions along the axial length of the tube.
A second tube
48
is fitted inside first tube
42
and has external threads (not shown) which operatively engage the internal threads of the first tube
42
such that the second tube can be advanced or retracted axially along first tube
42
by manual operation of a wheel
50
fixed to the end of second tube
48
. A freely rotating spindle
52
is positioned in the bore of second tube
48
and has a tool chuck
54
fixed to one end for holding hole saw
28
. The spindle
52
is fixed axially relative to the second tube
48
by thrust bearings (not shown) so that the spindle
52
moves with the second tube
48
as wheel
50
is manipulated. A driven end
56
of spindle
52
is adapted to receive a driver whereby spindle
52
may be rotated using a power drill (not shown).
According to the prior art method of cutting lock bolt
14
, drill plate
32
is attached to drawer panel
29
generally near lock bolt
14
and drill rig
30
is secured to drill plate
32
. Locking collar
44
is manipulated to allow first tube
42
to be adjusted such that hole-saw
28
is adjacent the surface of the drawer panel
29
. A power drill with an appropriate driver is fitted to the driven end
56
of spindle
52
and the drill is energized to rotate the spindle
52
and hole-saw
28
while being advanced through the surface of drawer panel
29
and subsequently through lock bolt
14
by hand manipulation of wheel
50
. A typical security container utilizes at least two lock bolts, operating in tandem, thus the prior art method stated above must generally be repeated on the second lock bolt
16
before access to the drawer can be gained.
FIG. 2
shows a partial section view of the prior art cutting method of
FIG. 1
taken along line
2
—
2
. Hole-saw
28
has penetrated the surface of drawer panel
29
and has advanced part way through lock bolt
14
. As depicted in
FIG. 2
, lock bolt
14
is substantially unsupported along its length and the cutting force applied by hole-saw
28
causes lock bolt
14
to bend in a direction away from the hole-saw
28
. The bending of lock bolt
14
in turn causes ends
58
of groove
60
, cut into lock bolt
14
, to pinch against hole-saw
28
, binding the hole-saw from rotation and damaging the carbide tips.
Accordingly, there is a need for an apparatus and methods for drilling through the lock bolt of a security container without the typical binding action which creates the various problems discussed above.
SUMMARY OF THE INVENTION
The present invention provides a method and apparatus for supporting a lock bolt of a security container while the lock bolt is being cut with a hole-saw to gain access to the container. The invention provides various advantages over previous methods and apparatus for cutting such lock bolts by constraining the lock bolt from bending and binding against the cutter. For example, the present invention reduces heat generation and tool chatter. The invention thus provides more efficient cutting and extends the service life of the cutter.
In one aspect of the present invention, a lock bolt support member has an engagement portion shaped to engage the surface of a lock bolt for a security container. The engagement portion of the support member may be inserted through an access hole that has been formed in a surface of the security container, near the lock bolt. A connecting portion of the support member remains outside the security container and mates with a locking mechanism such that the support member may be clamped between the lock bolt and the surface of the security container, thereby preventing the lock bolt from moving while it is being cut.
In another aspect of the invention, the engagement portion of the lock bolt support member is generally hook-shaped.
In another aspect of the invention, the connecting portion of the lock bolt support member includes screw threads. Accordingly the locking mechanism includes a first nut with screw threads that operatively engage the threads of the connecting portion. The locking mechanism thus can be adjusted with respect to the connecting portion so that the bolt support member can be clamped against the surface of the security container.
In yet another aspect of the invention, the locking mechanism includes a second nut with screw threads that operatively engage the threads on the connecting portion of the bolt support member such that the first nut is tightened to secure the lock bolt support member in position relative to the lock bolt and the second nut is tightened to retain the first nut from loosening.
In a furt
Day J. Wesley
Osborne Ernest M.
Howell Daniel W.
Lockmasters, Inc.
Wood Herron & Evans L.L.P.
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