Information
-
Patent Grant
-
6263713
-
Patent Number
6,263,713
-
Date Filed
Wednesday, March 3, 199925 years ago
-
Date Issued
Tuesday, July 24, 200123 years ago
-
Inventors
-
Original Assignees
-
Examiners
Agents
- Calfee Halter & Griswold LLP
-
CPC
-
US Classifications
Field of Search
US
- 070 358
- 070 360
- 070 361
- 070 492
- 070 493
- 070 422
- 070 375
- 070 378
- 070 392
- 070 421
- 070 387
- 070 DIG 75
- 070 31
- 029 4264
- 029 434
- 225 2
- 225 93
-
International Classifications
-
Abstract
A lock and a method for manufacturing the lock. The lock comprises a shell having an interior cavity, a plug received in the interior cavity rotatably and axially slidably therein and defining a keyway configured to receive a preselected key, and a tumbler insertable in the plug. The tumbler has a plug portion disposed at a first axial location within the plug and resiliently biased outwardly toward a locked radial position and associated with the keyway such that the preselected key inserted in the keyway locates the tumbler in an unlock position and a shell portion disposed at a second axial location in the shell wherein the second axial location is axially spaced from the first axial location. The shell, the plug and the tumblers are configured such that the tumblers are sheared between the plug and the shell when the plug and the shell are forced axially toward each other.
Description
BACKGROUND OF THE INVENTION
The present invention relates generally to cylinder locks having key operable tumblers. Cylinder locks have been widely used to secure doors and padlocks and in other applications. In certain applications, it is desirable that a single key fits a plurality of locks. For example in automotive applications, users may desire to have a single key that opens the doors, glove compartment and trunk that also operates the ignition. If one of the locks requires replacement at a later time, the replacement lock may require a new key for operation if the replacement lock is unable to be fitted to the original key.
U.S. Pat. No. 1,979,939 discloses a device and method for shearing projections of tumbler ends to fit a lock to a particular key. Spring loaded, wafer-like tumblers, having a length greater than the diameter of the plug of a lock, are inserted into the plug with the tumbler ends projecting axially beyond the plug. When a key is inserted in the keyway of the lock, the notches and cams on the blade of the key displace the tumblers and springs, projecting certain portions of the tumbler beyond the ends of the plug. A tool having two complementary cutters is used to shear the projected ends off the tumblers. When the key is removed and the plug is inserted in the shell, the springs are allowed to expand, forcing the tumblers to protrude into slots in the shell of the lock and preventing the rotation of the plug within the shell. As all of the tumblers are sheared together, a significant shearing force is required.
U.S. Pat. Nos. 5,697,239 and 5,735,153 disclose a method and apparatus for the manufacture of a pin tumbler cylinder lock with shearable assembly pins. The pins have a plurality of selectively weakened locations for an initial configuration of the lock corresponding to the shape of a notched key. The pins are biased radially into the plug of the lock by springs located in the lock shell. The pins can be sheared by the manufacturer or a locksmith, with the sheared portions of the pins functioning as the driver and the tumbler pins.
The disclosed methods and apparatus require the use of cutting tools or a significant shear force to fit the lock to a particular key. There is a need for a method of manufacture of a lock that provides greater case in keying or rekeying locks without comprising the security of the lock.
SUMMARY OF THE INVENTION
The present invention is related to a lock having a shell, a plug mounted in the shell and a plurality of tumblers that extend into the shell. The tumblers have a plurality of grooves notched on both ends such that when a key is inserted in the lock, the key lifts the tumblers according to the notches on the key, aligning the grooves on the tumblers. The shell and plug are forced axially toward each other shearing the tumblers along the aligned grooves to fit the lock to the key. The present invention is further directed to a shell and plug configuration that reduces the total shearing force required for shearing the tumblers and to a method of manufacturing a lock having shearable tumblers for a preselected key.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1
is a cross-sectional view of the lock constructed according to the present invention prior to the shearing of the tumblers;
FIG. 2
is a cross-sectional view of the lock in
FIG. 1
along lines
2
—
2
;
FIG. 3
is a cross-sectional view of the lock in
FIG. 1
along lines
3
—
3
;
FIG. 4
is a side view of a two-sided notched key;
FIG. 5
is a front view of a tumbler of an embodiment of the present invention;
FIG. 6
is a side view of the tumbler of
FIG. 5
;
FIG. 7
is a front view of a retention tumbler of an embodiment of the present invention;
FIG. 8
is a side view of the retention tumbler of
FIG. 7
;
FIG. 9
is a top view of a retention sleeve constructed according to the present invention;
FIG. 10
is a cross-sectional view of the retention sleeve in
FIG. 9
along plane
10
—
10
;
FIG. 11
is a flowchart showing the steps of assembling the lock according to the present invention
FIG. 12
is a cross-sectional view similar to the lock in
FIG. 1
in which the tumblers have been sheared by relative axial movement between the shell and the plug;
FIG. 13
is a cross-sectional view of the lock in
FIG. 12
along plane
13
—
13
;
FIG. 14
is a cross-sectional view of the lock in
FIG. 12
along plane
14
—
14
;
FIG. 15
is a cross-sectional view of the lock in
FIG. 12
along line
15
—
15
;
FIG. 16
is a cross-sectional view of
FIG. 14
in an unlocked position;
FIG. 17
is the lock in
FIG. 16
in the locked position;
FIG. 18
is a front view of a tumbler of another embodiment;
FIG. 19
is a side view of the tumbler in
FIG. 18
;
FIG. 20
is an enlarged cross-sectional end view of an embodiment of the present invention with the tumbler of
FIG. 18
;
FIG. 21
is a side view of the lock of
FIG. 20
;
FIG. 22
is a cross-sectional view of a third embodiment of the present invention;
FIG. 23
is top view of a fourth embodiment of the present invention shown illustratively without a retention sleeve;
FIG. 24
is a cross-sectional view of the tumbler in
FIG. 23
shown with a retention sleeve;
FIG. 25
is a side-elevational view of an apparatus for holding the lock assembly when shearing tumblers; and
FIG. 26
is a cross-sectional view of the apparatus of
FIG. 25
along plane
26
—
26
.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to
FIG. 1
, lock
100
, as shown in a loading position, comprises a substantially cylindrical shell
102
having a shell interior cavity
104
. Shell
100
has seven shell passageways
106
extending radially between the exterior of the shell
102
and the shell interior cavity
104
. The shell
102
is preferably made of zinc, brass, plastic or other suitable materials.
A turnable cylindrical plug
108
is axially mountable for rotatable movement within the shell interior cavity
104
of the shell
102
. The plug
108
has a plug collar
110
located at one end of the plug
108
and a plug tail
112
disposed axially from the plug collar
110
on the other end of the plug
108
. The plug tail
112
is connectable to a latch that drives a bolt or other locking devices to lock or open a door or other movable member as disclosed in the art. The plug
108
has a keyhole
113
leading to a keyway
114
configured for receiving the blade
128
of a key
116
. Plug
108
has seven plug passageways
118
extending radially from the keyway
114
through the plug
108
and opening into the shell
102
. The plug
108
has an outer diameter
109
that is less than the inner diameter
111
of the interior cavity
104
of the shell
102
, creating a shearing zone
120
between the shell
102
and the plug
108
. In the loading position of the lock as shown in
FIG. 1
, plug passageways
118
extend across the keyway
114
and are initially aligned with shell passageways
106
for receiving shearable, wafer-like, tumblers
122
. The plug
108
is preferably made of a zinc, brass, plastic or other suitable materials.
FIG. 1
shows the preferred embodiment according to the present invention in a loading position in which the tumblers
122
are loaded in the plug and shell passageways
118
and
106
respectively of the plug
108
and shell
102
before being sheared therebetween. In
FIG. 1
, the shell
102
and the plug collar
110
define a gap
150
for allowing axial movement of the plug
108
relative to the shell
102
along the shearing zone
120
. The dimension of the gap
150
is selected to allow sufficient penetration of the plug
108
into the shell
102
when shearing the tumblers
122
. Preferably the gap is between 0.04 inches and 0.06 inches, and most preferably, the gap is about 0.05 inches.
A tubular retention sleeve
152
is manufactured to fit over the exterior of the shell
102
and is securable to the shell
102
by a retention sleeve crimp
154
engaging the exterior of the shell
102
, as shown in FIG.
1
. Preferably the retention sleeve crimp
154
is in one of the shell passageways
106
, but the sleeve may alternatively engage with another recessed portion of the shell
102
. Referring to
FIGS. 2
,
3
,
9
and
10
, the retention sleeve
152
has a set of first slots
156
and a set of second slots
158
extending therethrough that are alignable with the shell and plug passageways
106
and
118
. Preferably the first set of slots
156
and the second set of slots
158
are interposed axially in sequence and are angularly displaced from each other around the sleeve by a sleeve displacement angle
160
. Angularly displacing slots
156
and
158
allows the insertion of the tumblers
122
into the plug and shell passageways
106
and
118
in two groups such that the tumblers
122
are radially and resiliently biased from the plug in radially opposite directions, as described in greater details hereinafter. The slots
156
and
158
have a rectangular portion
159
shaped to receive the tumblers
122
and a circular portion
161
shaped to receive the springs
178
. Sleeve angle
160
is measured from the center of the rectangular portion
159
of the sleeve slot
156
to the center of the rectangular portion
159
of the sleeve slot
158
. Preferably, sleeve angle
160
is less than 180° such that the one set of slots
156
and
158
allows the insertion of the tumblers
122
into alternative plug and shell passageways
106
and
118
while the other passageways are closed by the sleeve
152
. Most preferably, sleeve angle
160
is about 135°. Preferably, the sleeve angle
160
is between 5° and 180°, or more preferably 90° to 150°.
Referring to
FIGS. 2 and 3
, the lock is shown in the loading position with the shell passageways
106
and plug passageways
118
aligned, and shearable tumblers
122
extending radially from one side of the plug
108
to the other and into the shell passageways
106
. Each shell passageway
106
has a first shell opening
162
that is preferably wider than a second shell opening
164
. Similarly, each plug passageway
118
has a first plug opening
166
that is wider than a second plug opening
168
. The first plug opening
166
meets the second opening
168
forming a spring seat
170
within the plug
108
.
In
FIG. 2
, the sleeve
152
openings
156
are aligned with alternate shell and plug passageways
106
and
118
marked as A for loading with tumblers
122
. In
FIG. 3
, on the other hand, sleeve
152
has been rotated to align openings
158
with alternate plug and shell passageways B for loading tumblers
122
.
Keys adaptable for cylinder locks are either one or two sided, i.e., having notches on one side or both sides of the blade of the key, respectively. A one-sided key usually has about five notch locations with about eight different depths of cuts associated with each notch location. In contrast, a two-sided key is notched on both sides and may use as many as ten notch locations with about five different cut depths associated with each notch location. An example of a use for a two-sided key is in automotive cylinder locks. The two-sided key, having greater number of notch locations, can accommodate the various applications associated with the car, such as the ignition, doors, trunk, and glove compartment. In addition, automotive cylinder locks provide multiple levels of security through the use of secondary keys that only allow access to selected applications, such as the valet key. Moreover, a lock cylinder for use with two-sided keys allows removal of the key from the cylinder in either locked or unlocked positions.
A key
116
, adaptable for use with the present invention, is shown in
FIG. 4
as having a plurality of notch locations
124
with each having various different cut depths
126
on opposite edges of the blade
128
of the key
116
. Key
116
, has ten notch locations
124
and five different cut depths
126
on opposite edges of the blade
128
of the key
116
, creating 9,765,623 usable keying combinations.
Each tumbler
122
has a key blade abutting portion
138
located in a center opening
136
, as shown in FIG.
5
. The opening
136
is cut out from the tumbler
122
and is shaped to receive the blade
128
of the key to interface with the key notches
124
. Finally, each tumbler
122
has a protuberance
139
protruding laterally therefrom to define a ledge
140
and an outer tumbler seat
141
. The tumblers
122
are made of a suitable material, such as brass. Multiple grooves
130
are preferably coined or stamped on the surface of the tumblers
122
, as shown in
FIGS. 5 and 6
. Each tumbler
122
is wafer shaped and has a thickness
129
and five weakened zones defined by notches or grooves
130
on each side of the tumbler to facilitate and localize their shearing. Also, the grooves are arcuate in this embodiment with a shape corresponding to the shape of the shearing zone
120
defined between the plug and the shells. The groove widths
132
and depths
134
are selected to reduce the axial shear force necessary for shearing the tumblers
122
when configuring the lock with a preselected key. During this configuring operation, an axial shearing force is applied to shear the tumblers
122
by axially shifting the plug
108
and shell
102
relative to each other.
The grooves
130
have a radius of curvature
135
, preferably between the radius of the interior cavity
104
and the outer radius of the plug
108
. Each of the grooves
130
has a groove width
132
, preferably ranging from about 0.0060-0.010 inches. The grooves are spaced at a radial distance
133
from each other. The radial distance
133
preferably corresponds to the distance between the available notch depths
126
at each notch location of the key
116
. Preferably, the radial distance
133
is between about 0.015-0.030 inches. Most preferably, the radial distance
133
is about 0.025 inches. However, distance
133
can be modified to accommodate different keying systems. The grooves have a depth
134
, as shown in
FIG. 6
, and the preferred groove depth
134
is about 0.012 inches. The series of grooves
130
is positioned on the tumblers
122
such that the grooves
130
are alignable with the shearing zone
120
between the shell
102
and the plug
108
by preselected keys with the appropriate combination of notch locations
124
and cut depths
126
, as shown in
FIGS. 1-3
. The number and placement of the grooves
130
preferably correspond to the available cut depths
126
of the key notches
124
, although additional grooves
130
can be employed.
The tumblers
122
have a relative torque strength which corresponds to the amount of rotative torque the tumbler
122
can resist when the plug
108
is forced rotationally in the shell
102
with the tumblers
122
in the locked position against the walls of the passageways. It is desirable to maximize the rotative torque strength of the tumblers
122
while minimizing the axial shearing force required for shearing the tumblers
122
in manufacturing a lock. Accordingly, the tumbler groove
130
portions of the tumblers
122
arc not so weakened such that another insertable key, one having the same keyway configuration as the preselected key but with a different notch cut, could be torqued by hand or by a tool to further shear the tumblers
122
prior to key or tool failure. In other words, the weakest part of the grooves
130
, or the center
131
, is preferably strong enough to resist a torque force to the tumblers
122
equal to the maximum rotative force that can be applied through the keyhole
113
by any key or key-like tool that can be inserted into the keyhole
113
. This minimizes compromise in security while the lock is in service.
Referring to
FIGS. 1-3
and
15
, the shell
102
defines a retention groove
142
with a rearwardly facing retention wall
144
adjacent to the interior cavity
104
. The retention groove
142
circumferentially abuts the interior cavity forming stops
171
at either end of the groove, best shown in FIG.
15
. The plug
108
defines a retention slot
146
extending radially from the keyway
114
into the plug
108
and opens into the interior cavity
104
. A retention tumbler
148
, as shown in
FIGS. 7 and 8
, and a retention spring
147
, as shown in
FIG. 15
, are insertable within the retention slot
146
. In
FIG. 1
, the retention tumbler
148
is in an inactive position and out of engagement with the retention groove
142
of the shell
102
. When moved to its active position upon axial shifting of the plug
104
toward the shell
102
from the loading position of
FIG. 1
to the operative position of
FIG. 12
, the retention tumbler
148
is axially biased by the spring
147
within the plug
108
to extend outwardly toward the shell retention groove
142
and is allowed to rotate freely against the retention wall
144
. In this position, the retention tumbler
148
prevents the extraction of the plug
104
from the shell
102
.
The retention tumbler
148
preferably has a greater thickness
149
and a greater strength than the shearable tumblers
122
. Instead of a separate retention tumbler
148
, a plurality of retention grooves
142
may be disposed in the shell passageways
106
to engage the outwardly biased tumblers
122
for retaining the plug
108
within the interior cavity
104
.
The shell
102
further defines shell locking channels
172
, shown in
FIGS. 16 and 17
, that extend radially from the interior cavity
104
of the shell
102
for receiving the tumblers
122
when the lock
100
is in its operative position of FIG.
12
. Locking channels
172
engages the plug portions
200
of the tumblers
122
to prevent rotation of the plug
108
in the interior cavity
104
of the shell
102
. The locking channels
172
are shown as diametrically opposed, or located at 180°, with respect to each other. In this arrangement, the plug
108
can be rotated 180° between the lock and unlock positions so that the key
116
may be removed. However, locking channels
172
may be disposed in the shell at an angle less than 180° with respect to each other, where less rotation of the plug
108
in the interior cavity
104
is desired. In addition, the shell may comprise only one locking channel
172
, which will allow the key
116
to be removed from the lock
100
only when it is in the locked position. This is desirable for high security uses where the lock is to remain locked unless an intended user is present with the key
116
.
In the assembly of the lock
100
, as described in the flow chart in
FIG. 11
, the retention tumbler
148
and retention spring
147
are inserted into retention slot
146
, at axial location X in
FIG. 1
, of plug
108
. The retention tumbler
148
is depressed against the retention spring
147
when the plug
108
is inserted within the interior cavity
104
of the shell
102
and remains depressed within the plug
108
by the inner wall of the shell inner cavity
104
during the loading of the tumblers
122
. The plug
108
is thereafter inserted into the interior cavity
104
of the shell
102
along a center axis
174
such that the shell passageways
106
and plug passageways
118
are aligned, and the gap
150
is created between the shell
102
and the collar
110
of the plug
108
. The shell passageways
106
are aligned with plug passageways
118
such that the first shell openings
162
are aligned with first plug opening
166
and the second shell opening
164
are aligned with second plug opening
168
at axial locations A, as shown in
FIGS. 2 and 3
.
Retention sleeve
152
is placed around the shell
102
in a first loading position in which the first slots
156
are aligned with first shell openings
162
and first plug openings
166
at location A and the second shell openings
164
and second plug openings
168
are covered. The first loading position exposes alternating shell passageways
106
and plug passageways
118
at axial locations A in FIG.
1
. Springs
178
are inserted into the exposed shell and plug passageways
106
and
118
through circular portions
161
of the first slots
156
with the springs
178
abutting the spring seats
170
, as shown in FIG.
2
. Tumblers
122
are then inserted into the exposed shell and plug passageways
106
and
118
through the rectangular portions
159
of the first slots
156
such that springs
178
are held between ledges
140
of the tumblers
122
and the spring seats
170
, for biasing the tumblers
122
radially outward from the plug
108
toward the shell
102
.
The retention sleeve
152
is then rotated about the center axis
174
by an angle
182
to a second loading position. In the second loading position, second slots
158
of the retention sleeve
152
are aligned with the remaining shell and plug passageways
106
and
118
, at locations B in FIG.
1
. In the second loading position, the sleeve
152
closes off the shell and plug passageways
106
and
118
at locations A. The rotational angle
182
is correlated to sleeve angle
160
such that rotating the sleeve
152
with the first slots
156
aligned with shell and plug passageways
106
and
118
at axial locations A about the center axis
174
by rotational angle
182
aligns the second slots
158
with shell and plug passageways
106
and
118
, as shown in FIG.
2
. Springs
178
and tumblers
122
are disposed within the exposed shell and plug passageways
106
and
118
at location B with springs
178
held between ledges
140
and spring seats
170
, for biasing the tumblers
122
radially outwardly from the plug
108
toward the shell
102
in a direction opposite the tumblers
122
at location A, as shown in FIG.
3
.
FIG. 1
shows the lock
100
in its loading position and
FIGS. 2 and 3
show the tumblers
122
in a pre-shearing position. The tumblers
122
in the shell and plug passageways
106
and
118
in the first locations A are interposed axially with tumblers
122
in the second locations B such that the tumblers are resiliently biased upwardly and downwardly by the springs
178
in a sequentially alternating fashion along the direction of the axis
174
.
The retention sleeve
152
is rotated a second rotational angle
190
, preferably about 45°, about the center axis
174
to a closed position in which both the slots
156
and
158
are out of alignment with all shell and plug passageways
106
and
118
. The retention sleeve
152
is then secured by the retention sleeve crimp
154
on the exterior of the shell
102
by crimping a portion of the sleeve material therein for retaining the tumblers
122
in the shell
102
, as shown in
FIG. 1
, or in one of the shell passageways
106
, as shown in FIG.
12
. In the closed position, the retention sleeve
152
closes off the shell passageways
106
from the exterior of the lock
100
.
In this loaded position, the lock is now ready to be fitted to the preselected key
116
. A key adaptable for use with the present invention is the two-sided key
116
, as shown in FIG.
4
. Key
116
is inserted within the keyway
114
of the lock
100
through key hole
113
. The sloped positions
193
, shown in
FIG. 4
, of the key blade
128
cam the tumblers
122
, through abutment with the upper edges
138
of the tumbler openings
136
in contact with the notches
124
. The tumblers
122
are resiliently biased in opposite directions against the key
116
by the springs
178
. The insertion of the key
116
retracts the tumblers
122
inwardly into the plug
108
to an unlocked position in which certain grooves
130
are aligned along the shearing zone
120
. Shell
102
and the plug
108
are then forced axially toward each other along the center axis
174
to complete the assembly of the lock
100
into the operative operation, as shown in FIG.
12
. As the plug
108
is forced toward the shell
102
, tumblers
122
are sheared along the aligned grooves
130
, and the gap
150
between the shell
102
and plug collar
110
is closed. The size of gap
150
is selected such that penetration of the plug
108
into the shell
102
is halted at the assembled operative position shown in
FIG. 12
, when the collar
110
contacts the proximal or front side
137
of the shell
102
. In the operative position, as shown in
FIG. 12
, the axial travel of the plug
108
into the shell
102
is restricted such that the shell passageways
106
are no longer aligned with plug passageways
118
. Forcing the plug
108
into the shell
102
completely shears the tumblers
122
into releasable or shell portions
198
and plug portions
200
. The shell portions
198
remain in the shell passageways
106
inside the retention sleeve
152
, and the plug portions
200
remain in the plug passageways
118
.
In the operative position of
FIG. 12
, the plug portions
200
of the tumblers
122
are out of alignment with the shell passageways
106
by a distance
197
, which is preferably greater than the thickness
129
of the tumblers
122
. Accordingly, when the plug
108
is rotated within the interior cavity
104
, the plug portions
200
of the tumblers
122
abut the interior cavity wall
231
between the passageways
106
preventing the tumblers
122
from catching the shell passageways
106
when the plug
108
is rotated within the interior cavity
114
, as shown in
FIGS. 13 and 14
. Preferably, the distance
197
is between 0.036 and 0.076 inches. Most preferably, the distance
197
is 0.056 inches.
As explained above, once the lock
100
is in the operative position, the retention tumbler
148
is biased radially outward into the retention groove
142
abutting the retention wall
144
to prevent extraction of the plug
108
from the shell
102
, as shown in FIG.
15
. The retention tumbler
148
is extended into the retention groove
142
, and the plug
108
is rotatable within the shell
102
with the retention tumbler
148
abutting the retention groove
142
preferably in contact with the retention wall
144
. Since the rotation of the retention tumbler
148
is restricted about the center axis
174
when the retention tumbler contacts either one of the two stops
171
, the rotation of the plug
108
within the interior cavity
104
is likewise restricted. Preferably the stops
171
in the retention groove
142
sufficiently restrict the rotation of the plug
108
within the interior cavity
104
such that the plug portion
200
is retained in an unlocked position by the interior cavity wall
231
of the interior cavity
104
and allow the lock
100
to rotate from the locked position to the unlock position, as described below with reference to the locking channels
172
. Preferably, the retention tumbler
148
and the retention groove
142
allow at least 90° of rotation of the plug
108
with respect to the shell
102
, and most preferably up to about 270°.
Referring to
FIG. 16
, when the lock is in use and the key
116
is inserted within the keyway of the lock
100
in the locked position, the notches
124
of the key
114
depresses the spring
178
to shift the plug portions
200
out of the locking channel
172
, shown at the left side of FIG.
16
. While the key
116
remains in keyway
114
, the plug
108
can rotate within the interior cavity
104
of the shell
102
, and at this state, the lock
100
is still unlocked. Once the key
116
is removed, as shown in
FIG. 17
, the spring
178
is relaxed thereby radially extending the plug portion
200
into the oppositely disposed locking channel
172
until the tumbler seats
141
abut the interior wall
231
, preventing rotation of plug
108
within the interior cavity
104
of the shell
102
, and at this state, the lock
100
is unlocked.
Once the lock
100
is in the operative position, the shell
102
, containing the tumbler shell portions
198
within the shell passageways
106
, and the sleeve
152
can be removed and replaced with another shell having only locking channels
172
without interfering with the operation of lock
100
. The removed shell maybe reused for fitting another key and plug. In order to replace the shell
102
with one having only locking channels
172
, the retention tumbler
148
can be pushed inwardly from the retention groove
142
, depressing the retention spring
147
and thus allowing extraction of the plug,
108
from the internal cavity
104
of the shell
102
. During extraction, the tumbler shell portions
198
will fall out of the shell passageways
106
. The retention sleeve
152
may then be removed, and the shell
102
can be reassembled with new tumblers
122
. Preferably, however the shell
102
and sleeve
152
are left in place.
FIGS. 18 and 19
, show a modified embodiment of the tumbler. Here, tumbler
300
has straight grooves
302
disposed on opposite ends of the tumbler
300
, forming weakened zones to facilitate and localize the shearing of the tumblers
300
. The multiple grooves
302
are preferably coined or stamped on the surface of the tumblers
300
. The entire tumbler
300
is preferably coined or stamped from a sheet of material in a single operation. The groove widths
306
and depths
308
are selected to reduce the shear force necessary for shearing the tumblers
300
while preserving sufficient strength in the unsheared groove portion of the tumblers
300
, as shown in FIG.
19
. Preferably, the bases
303
of the grooves
302
are sharp or have a small radius of about 0.002 inches. As shown in
FIGS. 20 and 21
, tumblers
300
are insertable into a lock
316
having a shearing zone
318
formed between shell
320
and plug
322
. The series of grooves
302
is positioned on the tumblers
300
such that the grooves
302
are alignable with the shearing zone
318
by a preselected key
116
. Preferably the plug
322
has plug passageways
324
with laterally straight edges
326
across the opening of the plug passageways
324
.
FIG. 22
shows a lock
400
that comprises a substantially cylindrical shell
402
that has a shell interior cavity
404
. As shown, shell
400
has seven shell passageways
406
extending radially from the exterior of the shell
402
to the interior cavity
404
. Plug
408
has seven plug passageways
418
extending radially from a keyway
414
across the plug
408
. The plug passageways
418
are alignable with shell passageways
406
for inserting shearable tumblers
422
.
Whereas the widths of the shell passageways in the previous embodiment were substantially equal to each other, the shell passageways
418
of lock
400
have different widths. The shell passageways
406
at axial locations C preferably have the smallest axial width
426
, which is preferably larger than the axial width of the preformed tumblers
422
by a width D
1
of about 0.001 inches. The shell passageways
406
at axial locations D preferably have a larger axial width
428
, which is larger than the axial width of the preformed tumblers
422
by a width D
2
of about 0.005 inches. The shell passageways
406
at axial locations E have a still larger axial width
430
, which is preferably larger than the axial width of the preformed tumblers
422
by a width D
3
of about 0.009 inches. Finally, the shell passageway
406
at axial locations F preferably has the largest axial width
432
, which is preferably larger than the axial width of the preformed tumblers
422
by a width D
4
of about 0.015 inches.
While the proximal wall
434
of the shell passageways
406
are generally aligned with the proximal wall
436
of the plug passageways
418
, the distal wall
438
of the shell passageways
406
are disposed further toward the plug tail
412
, or distally, than the distal walls
440
of the plug passageways
418
. Thus, a gap of axial widths D1-D4 remains ahead of the shearable tumbler portions
442
.
In the assembly of the lock
400
, the plug
408
is inserted into the interior cavity
404
of the shell
402
along a center axis
424
such that the shell passageways
406
and plug passageways
418
are aligned creating the gap
444
to produce a shear distance
446
between the shell
402
and the plug collar
410
of the plug
408
. The tumblers
422
are inserted in the aligned plug and passageways
406
and
418
as in the previous embodiment. The plug
408
is thereafter forced axially into the shell
402
over the shear distance
446
, shearing tumblers
422
and closing the gap
444
between the shell
402
and plug collar
410
. The shear distances required for shearing each of the tumblers
422
inserted in the shell and plug passageways
406
and
418
are different for the tumblers
422
located at different axial locations C-F. Thus, the plug must be moved by a distance greater than D1 to shear the tumblers
422
at locations C, by a distance greater than D2 to shear the tumblers at locations D, by a distance greater than D3 to shear the tumblers
422
at locations E, and by a distance greater than D4 to shear the tumbler
422
at location F. As a result, the two tumblers
422
at C are sheared first. Then the two tumblers
422
at locations D and then at locations E's are sheared, and finally the tumbler at location F is sheared. This configuration of the shell
402
thus reduces the force required for shearing of the tumblers
422
, as less than all of the tumblers
422
are being sheared at anyone time, or at least the tumblers at different locations are in different stages of shearing at any point in time. The shearing of the tumblers
422
is thus staggered. The maximum force required to shear the tumblers
422
is thus 2/7 of the maximum force that would be needed if all of the tumblers
422
were sheared simultaneously.
The same effect can be achieved by providing equally sized shell passageways, but spaced unequally from each other. The disposal of the distal walls
438
of the shell passageways
406
at different distances from the tumblers
422
will ensure that less than all of the material that constitutes the shearable portions
442
of the tumblers
422
is sheared at one time, reducing the shearing force required to form the plug portions
448
.
Another embodiment of the invention is shown in
FIGS. 23 and 24
. The retention sleeve has been removed for clarity. In
FIG. 23
, the lock
500
has a front portion
502
, a back portion
504
and a center axis
506
. Lock
500
further comprises a shell
510
and a plug
512
having shell and plug passageways
513
and
514
, respectively, axially positioned in a series. Shell passageways
513
extend through the shell
510
forming shell shearing walls
515
and plug passageways
514
extend through the plug
512
, forming shearing walls
516
at the interface therebetween. In addition, each shell passageway
513
has a shell front wall
516
located toward the front portion
502
of the lock
500
and a shell back wall
518
located toward the back portion
504
of the lock
500
. Similarly, each plug passageway
514
has a plug front wall
519
located toward the front portion
502
of the lock
500
and a plug back wall
521
located toward the back portion
504
of the lock
500
.
Tumblers
520
are inserted within the passageways
513
and
514
. Each tumbler
520
has a front lateral side or shearing surface
522
facing the front portion
502
of the lock
500
and a back lateral side or shearing surface
524
facing the back portion
504
. The front and back sides
522
and
524
define the shearing portion of the tumbler
520
. The walls of the plug and shell passageways of the previous embodiments were shown as parallel with respect to each other and substantially perpendicular to the longitudinal axis of the lock. In contrast, the back walls
518
of the shell passageways
513
form a shearing angle
526
with a line perpendicular to the longitudinal axis
506
of the lock
500
. Similarly, the back walls
521
of the plug passageways
514
form the same shearing angle
526
with a line perpendicular to the longitudinal axis
506
. The shear angle
526
is preferably less than 20° and more preferably less than about 15°. Most preferably, the shear angle
526
is about 5°.
Each tumbler
520
has a first lateral end
528
and a second lateral end
530
where the first lateral end
528
is located closer to the back walls
518
and
521
of the shell and plug passageways
513
and
514
than the second lateral end
530
.
The passageways
514
of the lock
500
are positioned such that when an axial shear force is applied to the plug
512
in a direction parallel to the center axis
506
from the back portion
504
to the front portion
502
of the lock
500
, the front walls
516
and
519
gradually begin contacting the first lateral side
522
of the tumblers
520
, and the tumblers
520
are pushed toward the back walls
518
and
521
as the tumblers
520
are sheared across the cross-section thereof from the first lateral end
528
to the second lateral end
530
. The angled back walls
518
and
521
substantially secure the first lateral ends
528
in place and allow gradual movement of the tumblers
520
such that only the second lateral ends
530
are allowed to pivot toward the back walls
518
and
521
. The shearing persists until the entire lateral surface of the tumbler
522
is sheared. Accordingly, shearing of the tumblers
522
occurs from the first lateral end
528
to the second lateral end
530
laterally across the tumblers
522
. As the contact of the front walls
516
and
519
with the tumbler
520
is not the entire lateral surface of the tumblers
520
at any point in time, less shearing force is required to shear the tumblers
522
than shearing tumblers in an embodiment having parallel front and back walls of shell and plug passageways.
Additionally, about half of the back walls
518
and
521
are angled in a first lateral direction, and about the other half of the back walls
518
and
521
are angled in the opposite lateral direction. The net effect of the angled passageways
513
and
514
is that the back walls
518
and
521
tend to twist the plug
512
in one direction, increasing the force of the tumblers
522
against the back walls
518
and
521
that are oriented in the opposite direction. Accordingly, the lateral orientations of the back walls
518
and
521
of the passageways
513
and
514
are preferably staggered axially to prevent the front portion
502
of the plug
512
from being twisted one way while the back portion
504
is twisted the opposite way, thereby stabilizing the lock
500
during the shearing process.
FIGS. 25 and 26
illustrate an apparatus that may be used for mounting the lock assembly in a loading position and for applying the shearing force required for shearing the tumblers. The shearing apparatus
600
includes a fixture
602
, which may be a wrench, with a lock holder
604
having a substantially semicircular holder recess
606
for receiving the lock
100
and a plunger
608
connected to the fixture for pivotal movement with respect to the holder
604
. Lock
100
, in its loading position with its shell
102
, plug
108
, key
116
and unsheared tumblers
122
placed within the shell
102
and plug
108
, is placeable in the holder recess
606
of the holder
604
. Lock
100
is placed within the holder
604
by inserting the holder
604
into and abutting the walls of a circumferential groove
610
on the shell
102
such that the walls of the groove
610
abuts the holder recess
606
with the plunger
608
abutting the external surface of the plug collar
110
.
To shear the tumblers
122
, lock
100
, including shell
102
, plug
108
, key
116
and tumblers
122
, in the loading position with the shearing gap
150
, is placed in the lock holder
604
with the shearing gap
150
between the circumferential groove
610
and the plug collar
110
. A force is applied to the lock
100
by pivoting the plunger
608
toward the holder recess
606
, and the plug collar
110
is forced axially toward the circumferential groove
610
, effectively closing the gap
150
and shearing the tumblers
122
. After the tumblers
122
are sheared, the plunger
608
is released and the lock
100
, now fitted for key
116
, is removed from the shearing apparatus
600
by sliding the holder
604
away from the groove
610
.
EXAMPLE
The above described aspects of the lock constructed according to the present invention will now be described with reference to the following non-limiting examples. These examples are merely illustrative of one of the preferred embodiments of the present invention and are not to be construed as limiting the invention, the scope of which is defined by the appended claims. These examples illustrate several of the above described manners in which the total shear force required to shear the tumblers is minimized while maximizing the total rotative torque strength of the tumblers to maintain the level of security desired for the lock.
Table 1 is a tabulation of the test results using a lock having tumbler with arcuate grooves, as shown in
FIGS. 5 and 6
, stamped across the lateral surface of the tumblers and a substantially cylindrical plug. Table 2 is a tabulation of the test results using a lock having tumbler with substantially straight grooves, as shown in
FIGS. 18 and 19
, stamped across the lateral surface of the tumblers and a plug having a correspondingly straight or flattened surface across the openings of the plug passageways, as shown in
FIGS. 20 and 21
. Other common parameters included the shell having an inside diameter of 0.686 inches at the inner cavity and a plug having an outside diameter of 0.680 inches, creating a shell and plug shearing zone of 0.006 inches. The tested tumblers were made from hardened brass having a groove thickness of 0.004 inches. The plug and shells were made from zinc plated metals. The varied parameters, in addition to the shape of the grooves stamped on the tumblers included the outside thickness of the tumblers
313
as shown in
FIG. 19
, shear contact angle
526
between the shearing surface of the back walls
518
and
521
and the back tumbler side
524
, as shown in FIG.
23
. Tumblers having outside thickness of 0.012 inches and 0.005 inches were tested. Shearing angle
526
of 0°, 4° or 8° as shown in FIG. were also tested.
The tests measured the required shearing force to shear the tumblers to a configuration in which the lock is operable with a particular key. These tests also measured the torque strength of the operable portions of the tumblers against the passageways, corresponding to the amount of torque the tumbler can resist when the plug is forced rotationally in the shell with the tumblers in the locked position. As stated earlier, it is desirable to maximize the rotative torque strength of the tumblers while minimizing the axial shearing force required for manufacturing a lock that is easily fitted with any insertable key.
TABLE 1
|
|
Arcuate/Curved Grooves
|
Shear Angle (°)
|
angle of contact
|
between the
|
passageways and
|
the tumblers
Tumbler
Shear
Torque
|
(as shown in
Thickness
Force
(lb-in)
|
Example
FIG. 23)
(in)
(lbs)
Strength
|
|
A1
0
0.005
200
31.75
|
A2
4
0.005
70.6
31.75
|
A3
4
0.012
100
51.75
|
A4
8
0.005
41
31.75
|
A5
8
0.012
71
51.75
|
|
TABLE 2
|
|
Straight Grooves
|
Shear Angle (°)
|
angle of contact
|
between the
|
passageways and
|
the tumblers
Tumbler
Shear
Torque
|
(as shown in
Thickness
Force
(lb-in)
|
Example
FIG. 23)
(in)
(lbs)
Strength
|
|
S1
0
0.005
230
45.25
|
S2
4
0.005
67.8
45.25
|
S3
4
0.012
100
47.5
|
S4
8
0.005
54.5
45.25
|
S5
8
0.012
91
47.5
|
|
These tests demonstrated generally that a tumbler having a thickness of 0.012 in. requires greater total shear force than a tumbler having a thickness of 0.005 in. The maximum torque strength of tumblers, or the maximum rotative torque applied between the shell and plug that the tumblers were able to withstand before failing, varied more significantly between the two thicknesses for tumblers having arcuate grooves than for tumblers having straight grooves. A lock having arcuately grooved tumblers and angled contact surfaces between the passageways and the tumblers required less total shear force to shear the tumblers than a lock without angled contact surfaces between the passageways and the tumblers. By reducing the contact surface between the passageways and the tumblers at any point in time during shearing, the total shear force required for shearing is significantly reduced. Similarly, a lock having straight grooved tumblers and angled contact surfaces require 43% of the total shear force required to shear the tumblers than a lock without angled contact surfaces. Most notably, a lock having 0.005 in. thick tumblers and an 8° shear contact angle between the passageways and the tumblers required only 24% of the shear force than a lock having the same tumblers but without the angled shear contact surfaces, while maintaining the same tumbler torque strength.
It will be appreciated that those skilled in the art may devise numerous modifications and embodiments. It is intended that the following claims cover all such modifications and embodiments as fall within the true spirit and scope of the present invention.
Claims
- 1. A lock, having a longitudinal axis and comprising:(a) a shell having an interior cavity; (b) a plug received in the interior cavity rotatable therein and defining a keyway configured to receive a preselected key; (c) at least one spring disposed within the plug; and (d) a plurality of tumblers, each having: (i) a plug portion disposed at one of a plurality of first axial locations along said axis and within the plug wherein the plug portion is resiliently biased by the at least one spring radially outwardly toward a locked radial position and associated with the keyway such that said preselected key inserted in the keyway locates the plug portion in an unlocked radial position; and (ii) a shell portion disposed at one of a plurality of second axial locations along said axis and within the shell wherein the second axial locations are axially spaced from the first axial locations.
- 2. The lock of claim 1, wherein said shell and plug portions of each one of the tumblers are portions of a single tumbler sheared from each other at a location between the plug and the shell such that:(a) when the plug portion is in said locked radial position, the plug portion is disposed in an interface position with the shell to restrict relative rotation of the plug within the shell; and (b) when the plug portion is in the unlocked radial position, the plug portion is disposed in a non-interface position with the shell to permit the rotation of the plug within the shell.
- 3. The lock of claim 2, wherein:(a) a plurality of said tumbler plug portions are disposed at axially spaced locations within said plug and biased outwardly from the plug; and (b) the shell further comprises an external surface and a plurality of passageways extending radially from said interior cavity toward the external surface for receiving a plurality of said tumbler shell portions.
- 4. The lock of claim 3, wherein the shell further comprises at least one first locking channel extending from said interior cavity toward said external surface for engaging said plug portion of the tumbler in said locked position.
- 5. The lock of claim 1, wherein said shell portion is out of alignment with said plug portion.
- 6. A lock, comprising:(a) a plug defining a keyway for receiving a preselected key; (b) a plurality of tumblers receivable in the plug for radial movement therein; (c) a shell having an interior cavity and an exterior surface and defining a plurality of passageways radially connecting the interior cavity to the exterior surface for receiving the tumblers and further defining a locking space extending from said interior cavity toward said exterior surface to receive the tumblers in locking association therein for preventing rotation of the plug; and (d) at least one spring disposed within the plug for biasing the tumblers radially outwardly from the plug; wherein the plug is rotationally and axially receivable within the interior cavity about a rotational axis, and the tumblers are receivable through the passageways for insertion into the plug in a loading position and arc out of alignment with the locking space wherein said plug and interior cavity of said shell define a shearing zone such that when the plug and shell are biased axially with respect to each other with a preselected axial shearing force, the tumblers are sheared to an operative position having a plug portion and a shell portion, the plug portion of said tumblers in the operative position permitting rotation of the plug within the shell in an unlocked position and interfacing with the shell to restrict relative rotation of the plug in a locked position, wherein the at least one spring is disposed for biasing the tumblers toward the locked position.
- 7. The lock of claim 6, wherein each tumbler has a plurality of weakened zones having a weaker strength relative to the rest of the tumbler with one of said weaker zones disposed at said shearing zone in said loading position when said preselected key is inserted in said keyway.
- 8. The lock of claim 7, wherein:(a) the tumblers further comprise opposed sides connected by edges such that said weakened zone extends laterally across the sides in a predetermined shape; and (b) said plug has a shearing edge associated with said plug portion of said tumblers and defining an outer contour having generally said predetermined shape for supporting the plug portion upon the application of said axial shearing force.
- 9. The lock of claim 8, wherein said predetermined shape is arcuate.
- 10. The lock of claim 8, wherein said predetermined shape is substantially straight.
- 11. The lock of claim 6, wherein the tumblers are movable within the plug in different radial directions with respect to the plug.
- 12. The lock of claim 6, wherein said shell further defines a groove extending circumferentially about the exterior thereof for engaging a tool for applying said preselected force.
- 13. The lock of claim 6, further comprising a retention sleeve mountable around the exterior of the shell in a position covering the passageways for retaining the tumblers therein.
- 14. The lock of claim 13, wherein the retention sleeve defines sleeve slots alignable with the passageways for loading the tumblers into the plug therethrough.
- 15. The lock of claim 14, wherein:(a) first and second of the shell passageways arc axially spaced along said rotational axis; and (b) first and second sleeve slots are angularly displaced about the rotational axis by an angle such that the sleeve is positionable on the shell in: (i) a first loading position in which the first sleeve slots are radially aligned with the first shell passageways with the second sleeve slots out of alignment with the second shell passageways, and (ii) a second loading position in which the second sleeve slots are radially aligned with the second shell passageways with the first sleeve slots out of alignment with the first shell passageways, each sleeve slot and corresponding shell passageway when aligned permitting the insertion therein of one of said tumblers.
- 16. The lock of claim 6, wherein said locking space is angularly displaced about said rotational axis from said plurality of shell passageways.
- 17. The lock of claim 16, wherein said locking space is angularly displaced about said rotational axis from said plurality of shell passageways by an angle of about 90°.
- 18. The lock of claim 6, wherein said locking space comprises a locking channel extending substantially in parallel to said rotational axis.
- 19. The lock of claim 6, wherein said locking space is out of alignment with said shell portions.
- 20. A lock having a longitudinal axis, comprising:(a) a shell including an interior cavity and a plurality of shell passageways having opposed lateral shell walls extending laterally of said longitudinal axis; (b) a plug defining a keyway and being axially slidably receivable in the interior cavity and defining a plurality of plug passageways having opposed lateral plug walls radially aligned with said shell passageways; (c) a tumbler disposed in each of said aligned shell and plug passageways and associated with the keyway such that a preselected key inserted in the keyway locates the tumblers in an unlocked radial position, each tumbler having: (i) a plug portion with a first shearing surface facing one of the opposed lateral shell and plug walls, the first shearing surface of all of the plug portions collectively comprising collective first shearing surfaces, and (ii) a shell portion with a second shearing surface facing another opposed shell and plug walls, the second shearing surface of all of the shell portions collectively comprising collective second shearing surfaces; and (d) the shell portions of said tumblers being attached to the plug portions in a pre-formed configuration and shearable from the plug portions of the tumblers to a formed configuration upon axially biasing one wall of the plug toward the opposite wall of the shell with a predetermined axial shearing force; and (e) wherein the opposed walls of the shell and plug passageways are in association with the tumblers for progressively contacting the total collective first or second surfaces during the application of said preselected axial shearing force for shearing the tumblers.
- 21. The lock of claim 20, wherein the wall of each plug and shell passageways facing in a direction opposite the direction of the axial shearing force applied to said first collective shearing surfaces is oriented at an acute shearing angle with respect to the opposite wall of each plug and shell passageway.
- 22. The lock of claim 21, wherein the acute shearing angle is between about 2° and 15°.
- 23. The lock of claim 20, wherein the wall of each plug and shell passageways facing in a direction opposite the direction of the axial shearing force applied to said first collective shearing surfaces is oriented at an acute shearing angle with respect to the tumblers.
- 24. The lock combination of claim 20, wherein the opposed lateral shell walls of a first shell passageway are spaced axially from each other by a first distance and the opposed shell walls of a second shell passageway are spaced from each other by a second distance different than the first distance.
- 25. The lock combination of claim 24, wherein the plug portions of said tumblers in said formed configuration are disposed in:(a) an unlocked position permitting rotation of the plug within the shell; and (b) a locked position interfacing with the shell to restrict relative rotation of the plug within the shell.
US Referenced Citations (31)
Foreign Referenced Citations (3)
Number |
Date |
Country |
266379 |
Oct 1913 |
DE |
2624320 |
Jan 1977 |
DE |
1528882 |
Dec 1989 |
SU |