Note: Descriptions are shown in the official language in which they were submitted.
2056461
Cylinder Lock
Field of the Invention
The present invention relates, in general, to lock devices, and more
particularly, to a cylinder lock that provides significant resistance to
damage or tampering.
Prior Art
In a conventional cylinder lock, a key cylinder is rotatably mounted
within a casing of the lock and a proper key may be inserted into and rotated
with the key cylinder from locked to unlocked position. Tumblers are slida-
bly disposed within slits formed in the key cylinder to engage with or disen-
gage from a groove formed in a casing of the lock. In prior art cylinder
locks, the tumblers engage with the groove in the casing to prevent unauthor-
ized rotation of the key cylinder. Therefore, these locks might involve a
risk of unallowed attempts to unlock or tamper by damaging the tumblers.
For example, as disclosed in U. S. Patent No. 4,903,512, a free-turn
type cylinder lock has been proposed wherein the key cylinder is designed to
freely rotate against unallowed attempt to unlock when rotational force is
applied to the key cylinder. Such a cylinder lock includes a sleeve ro-
tatably arranged in the casing; and a key cylinder supported within the sleeve
for rotation. When a correct key is inserted into the key cylinder, the
tumblers within the key cylinder are moved for disengagement from the groove
formed in the sleeve, and thereby the key cylinder may be rotated independent-
ly of the sleeve so that a sliding ring engages with a lock-piece operating
member to actuate the lock. If an incorrect key is inserted into the key
*
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cylinder, the sleeve is kept in engaged condition by the tumblers with the key
cylinder to rotate them together. This prevents rotation of the lock-piece
operating member to inhibit unauthorized actuation of the lock.
If an incorrect key is inserted into the key cylinder of such free-turn
type cylinder lock and then rotated, the key cylinder freely rotates with the
incorrect key, and there will not be produced excessive force that might
damage the tumblers and therefore significant resistance of the locks to
damage is obtained. However, the lock disclosed in U. S. Patent No.
4,903,512 has the disadvantage that the key cylinder cannot be turned smoothly
once an unauthorized key is inserted and rotated. A torsion coil spring is
provided between the front plate and the key cylinder within the lock in order
to automatically return the rotated key cylinder to its initial position. If
an incorrect key is inserted into the key cylinder and rotated, the sleeve and
the key cylinder are freely turned together, then the torsion coil spring
produces a resisting force. However, if they are rotated over a predeter-
mined angle, the torsion coil spring restricts rotation of the key cylinder.
This might pose a possibility that the torsion coil spring may be broken or
damaged. However, without the torsion coil spring, the key cylinder will
not be automatically returned to its initial position when the key cylinder is
rotated with the correct key. Accordingly, the prior art lock has another
disadvantage as it is difficult to apply same to remote locking de~ices uti-
lizing radio wave or infrared ray. Furthermore, due to axial movement of
the sliding ring of the lock of the above U. S. Patent along the key cylinder,
another shortcoming is that the lock is large in size and become complex in
structure.
Accordingly, an object of the present ir.vention is to provide a novel
cylinder lock with a key cylinder capable of freely rotating against an unau-
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thorized attempt to unlock it.
It is another object of the present invention to provide a compact-sized
free-turn type cylinder lock.
Summary of the Invention
The cylinder lock according to the present invention includes a casing;
a sleeve rotatably disposed in the casing; a key cylinder disposed rotatably
within the sleeve; tumblers slidably disposed within each slit formed in the
key cylinder for engagement with the sleeve; and a connector which is driving-
ly connected to a lock device. The cylinder lock also comprises a cam pro-
vided on the key cylinder; and at least a pin disposed radially slidably in an
opening provided in the sleeve. The pin is moved within the opening of the
sleeve by the cam on the key cylinder when the key cylinder is turned by a
proper key relative to the sleeve to a predetermined angle so that the pin
comes into engagement with the connector to rotate the connector together with
the key cylinder and to unlock the lock device.
The cylinder lock may comprise a return spring disposed between the
sleeve and the cylinder; a first return spring disposed between the sleeve and
the cylinder; and a second return spring disposed between the casing and the
connector.
The connector has a cylindrical portion extending outwardly of the
sleeve and rotatable relative to and separately of the sleeve. The cylin-
drical portion has a resilient member provided thereon for resiliently urging
the pin inwardly.
When an correct key is inserted into the key cylinder, the tumblers in
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the cylinder are moved away from the sleeve for disengagement to cause the key
cylinder to turn independently of the sleeve. Then, when the key cylinder
is manually rotated, the cam in the key cylinder is rotated. As the pin
is in abutting engagement with the cam, the pin slides radially outwardly in
the opening in the stationary sleeve and is brought into engagement with the
connector. Thus, the key cylinder is rotated within an angular range for
sliding of the pin against elastic force of the first return spring. Within
the angular range for sliding of the pin, the pin radially slides with rota-
tion of the key cylinder against elastic force of the resilient member at-
tached to the connector, but neither the sleeve nor the connector will turn at
this time. When the key cylinder is rotated further over the angular range
for sliding of the pin, the connector is started to rotate during which the
pin is rotated together with the key cylinder, sleeve and connector against
elastic force of the second return spring, thereby rendering the connector to
rotate into a locking or unlocking position. If manually rotational force
is released from the correct key, the connector, sleeve and key cylinder are
returned to their original position within the rotating range for the connec-
tor by resilient force of the second return spring between the casing and the
connector. Subsequently, the key cylinder is returned to its original
position within the angular range for sliding of the pin by elastic force of
the first return spring, whereby the pin is moved radially inwardly to the
original position by elastic force of the resilient member.
When the key cylinder is rotated with an incorrect key, the key cylinder
is retained in the engaged condition with the sleeve by means of the tumblers
so that it turns together with the sleeve. Thus, since the key cylinder
will not rotate relative to the sleeve, the pin will not radially move within
the opening in the sleeve. Therefore, the key cylinder will not be connect-
20~6461
ed to the connector via the pin, thus preventing rotation of the connector.
The above-mentioned as well as other objects of the present invention
will become apparent during the course of the following detailed description
and appended claims.
Brief Description of the Drawings
Fig. 1 is a cross-sectional view of a cylinder lock according to the
present invention.
Fig. 2 is a cross-sectional view taken along line 2-2 of Fig. 1.
Fig. 3 is a cross-sectional view taken along line 3-3 of Fig. 1.
Fig. 4 is a cross-sectional view taken along line 4-4 of Fig. 1.
Fig. 5 is cross-sectional view taken along line 5-5 of Fig. 1.
Fig. 6 is cross-sectional view taken along line 6-6 of Fig. 1.
Fig. 7 is a rear view of the cylinder lock.
Fig. 8 is a cross-sectional view taken along line 8-8 of Fig. 7.
Fig. 9 is a cross-sectional view taken along line 9-9 of Fig. 7.
Fig. 10 is a plan view illustrating an end of the cylinder lock.
Fig. 11 is a partial cross-sectional view indicating the key cylinder
and sleeve.
Fig. 12 is a cross-sectional view with the key cylinder turned with a
proper key to the maximum angular position within the angular range for slid-
ing of a pin.
Fig. 13 is a cross-sectional view with the key cylinder turned within
the angular range of rotation of the connector.
Fig. 14 is a cross-sectional view with the key cylinder returned within
the angular range for sliding of the pin.
Fig. 15 is a cross-sectional view with the key cylinder returned to a
20~1i461
position for removing the key.
Fig. 16 is a cross-sectional view with the key cylinder turned to an
angle of about 20~ with an unacceptable key.
Fig. 17 is a cross-sectional view with the key cylinder turned to an
angle of about 90~.
Fig. 18 is a cross-sectional view with the key cylinder turned to an
angle of about 120~.
Fig. 19 is a cross-sectional view with the key cylinder turned at an
angle of about 360~.
Fig. 20 is a cross-sectional view illustrating the relationship between
the sleeve and key cylinder which has been turned by a proper key to an angle
of about 20~ from the position of Fig. 3.
Fig. 21 is a cross-sectional view illustrating the relationship between
the sleeve and key cylinder which has been turned by the proper key to an
lS angle of about 65~ from the position of Fig. 3.
Fig. 22 is a cross-sectional view illustrating the relationship between
the connector and the casing when thè key cylinder has been turned by the
proper key to an angle of about 65~ from the position of Fig. 4.
Detailed Description of the Invention
Referring to Figs. 1 to 22, an embodiment of the present invention will
be described.
As illustrated in Fig. 1, the cylinder lock 10 according to the present
invention comprises a casing 11, a sleeve 12 rotatably disposed within the
casing 11, and a key cylinder 14 rotatably positioned in sleeve 12. As
illustrated in Fig. 8 and Fig. 11, the key cylinder 14 has a plurality of tum-
blers 13 slidably disposed within slits 14d formed in the key cylinder 14 so
2056~61
that the tumblers 13 may protrude into and be engaged with groove 12a of
sleeve 12, and the key cylinder 14 is retained in an engaged condition with
sleeve 12 by means of tumblers 13 in a well known manner. As will be appar-
ent from Fig. 2, which shows a cross-sectional view along line 2-2 of Fig. 1,
formed on the key cylinder 14 is a cam 15 to which each inner end of a pair of
pins 16 is abutted. The outer end of each pin 16 is radially slidably
positioned in a corresponding opening 12b radially formed in the sleeve 12.
As shown in Figs. 1, 7 and 8, a connector 18 is rotatably attached to an inner
end 14c of the key cylinder 14 for example by an E-ring 23. The connector
18 has a cylindrical portion 19 positioned outside the sleeve 12 and may
rotate relative to and independently of sleeve 12. Formed in the cylindri-
cal portion 19 is a radial hole 19a in which a pin 20 and a spring 21 are
positioned to resiliently urge each pin 16 inwardly toward the cam 15. A
plate 22 is fixed to the cylindrical portion 19 to prevent detachment of the
spring 21. The pin 20 has its outer diameter approximately equal to that of
pin 16. When a correct key is removed from key cylinder 14, the outer end
of the pin 16 does not protrude outside the opening 12b of sleeve 12, but may
be positioned at the boundary between sleeve 12 and cylindrical section 19.
As illustrated in Fig. 3 showing a cross-sectional view taken along line 3-3
of Fig. 1, a first return spring 17 is disposed within a space defined by an
arcuate groove 14a of key cylinder 14 and arcuate groove 12c of sleeve 12.
Fig. 4 shows a cross-sectional view along line 4-4 of Fig. 1 in which the
sleeve 12 is rotatably positioned inside the casing 11. Fig. 5 shows a
cross-sectional view along line 5-5 of Fig. 1 in which a latch member 30 and a
spring 31 are positioned in an opening lla formed in casing 11. The latch
member 30 has a claw 30a which is resiliently urged toward the outer surface
of the sleeve by the spring 31. A plate 32 is fixed to the casing 11 to
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prevent detachment of the sp-ing 31. The claw 30a of latch member 30 en-
gages with a notch 12d formed in sleeve 12. Fig. 6 shows a cross-sectional
view along line 6-6 in which a notch 14b is formed in key cylinder 14 to
receive a latch member 33 and a spring 34 to elastically urge the latch member
33 outwardly. A claw 33a is formed with the latch member 33 to engage with a
notch llb formed in the casing 11. As shown in Figs. 8 and 9, a second
spring 34 is wound around the cylindrical portion 19 of the connector 18.
The cylindrical portion 19 has a notch defined by edges l9b and l9c, and the
casing 11 has a notch defined by edges llc and lld. Ends 34a and 34b of
the second spring 34 are respectively engaged with edges l9b and l9c of the
cylindrical portion 19, and edges llc and lld of the casing 11. The casing
is formed with a flange lle. Not shown, but the connector 18 is drivingly
connected to a locking mechanism such as a door lock device by a rod in a
known manner.
Before a key is inserted into the cylinder lock 10, the sleeve 12, key
cylinder 14 and connector 18 are in the locked condition as shown in Figs. 1
through 9. When an correct key is inserted into the key cylinder 14, the
tumblers 13 are moved in the key cylinder 14 for disengagement from the sleeve
12, thus permitting key cylinder 14 to rotate independently of the sleeve 12.
,o Then, when the key cylinder 14 is rotated, the sleeve 12 is held in a static
condition due to its engagement with the latch member 30, while the pin 16
slides outwardly within the opening 12b of sleeve 12 from the inner position
of Fig. 2 to the outer position of Fig. 12 by means of the rotating cam 15 of
the key cylinder 14. Accordingly, the outer end of the pin 16 comes into
engagement with the hole l9a formed in the cylindrical portion 19 of the
connector 18.
Therefore, when the key cylinder 14 is turned within the angular range
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for sliding of the pin 16 against elastic force of the first return spring 17
from the initial position of Fig. 2 to the position shown in Figs. 12, the
first return spring 17 is compressed as shown in Figs. 3 and 20. As the
key cylinder 14 turns within the angular range for sliding of the pin 16, the
pin 16 radially slides against elastic force of spring 21 within the cylindri-
cal portion 19 without rotation of the sleeve 12 by the latch member 30 and
connector 18 due to the only radial movement of the pin 16. When key cylin-
der 14 is further rotated beyond the angular range for sliding of the pin 16,
the key cylinder 14, sleeve 12, pin 16 and connector 18 are together rotated
from the position shown in Fig. 12 to that in Fig. 13 against elastic force of
the second return spring 34 in the rotating range of the connector 18 which
thus can be turned to a locked or unlocked position. The first return spring
17 is then forced from the condition of Fig. 20 to the state of Fig. 21 while
the cyllndrical portion 19 is moved from the locked position of Fig. 4 to the
rotated condition of Fig. 22.
When manual operation force is released from the rotated key, the second
return spring 34 positioned between casing 11 and connector 18 forcibly and
elastically pushes the connector 18, sleeve 12 and key cylinder 14 to return
from the rotated position of Fig. 13 to the initial position of Fig. 14 in the
angular range of rotation of connector 18. Subsequently, the key cylinder
14 is forced to return from the position of Fig. 14 to the initial position of
Fig. 15 by virtue of elastic force of the first return spring 17 within the
angular range for sliding of the pin 16 which is then radially and inwardly
moved by elastic force of the spring 21 to the initial position.
On the other hand, if the key cylinder 14 is rotated by an incorrect
key, it is moved from the locked condition of Fig. 2 to the condition of Fig.
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16, while the key cylinder 14 is retained in engaged condition with the sleeve
12 by tumblers 13 to rotate the key cylinder 14 and the sleeve 12 together.
Thus, without production of relative rotation of the key cylinder 14 to the
sleeve 12, the pin 16 will not radially move within opening 12b of sleeve 12.
In other words, the key cylinder 14 will not engage with connector 18 via pin
16, thus preventing rotation of the connector 18. Therefore, the sleeve 12
and key cylinder 14 are freely rotated as Figs. 17, 18 and 19 respectively
indicate rotation thereof to about 90~, 120~ and 360~.
As above-mentioned, the cylinder lock 10 according to the present inven-
tion allows the key cylinder 14 to turn together with sleeve 12 when an incor-
rect key is used to unlock, thus preventing rotation of connector 18. There-
fore, no excessive external forces will be exerted on the tumblers 13, thus
providing significant resistance to damage. Moreover, since the pin 16 may
move radially, the key cylinder 14 may be made in reduced length for reduced
size of the cylinder lock 10.
The present invention is not limited to the aforedescribed embodiment
but may be modified in various ways. For example, a single pin 16 is
utilized to connect the key cylinder 14 and the connector 18. In addition,
pin tumblers may be used in lieu of tumblers 13 of disk type in the above
embodiment. The cam 15 may be formed in an additional member which can
rotate together with key cylinder 14.
As described above, the cylinder lock according to the present invention
provides significant resistance to damage, thus effectively preventing unau-
thorized intrusion or theft.
