Lock with clutching function

A lock includes a body, a wheel, an outside spindle, and a locking plug. The outside spindle includes a front end having an extension not in contact with a circumferential wall defining a through-hole of the wheel. When the locking plug is in an unblocking position allowing retraction operation of a latch bolt, the front end of the outside spindle is engaged with the wheel to allow joint rotation of the outside spindle and the wheel. When the locking plug is moved from the unblocking position to the blocking position not allowing retraction operation of the latch bolt, movement of a push member pushes the front end of the outside spindle away from the through-hole of the wheel such that the front end of the outside spindle is disengaged from the circumferential wall of the through-hole of the wheel, thereby disengaging the outside spindle from the wheel.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a lock. More particularly, the present invention relates to a lock with a clutch function, allowing free rotation of the outer handle when the lock is in a locked state.

2. Description of the Related Art

U.S. Pat. No. 4,583,382 to Hull discloses a door lock with an outside handle that cannot be turned when in a locked state. However, the internal parts of the door lock could be damaged if the outside handle is frequently depressed when the user is not aware of the locking state of the lock. Also, the internal parts of the door lock could be damaged if overtorque is applied to the outside handle.

U.S. Pat. No. 6,993,946 to Shen discloses a lock that allows free rotation of the outside handle when the lock is in a locked state. However, assembly of the lock is troublesome.

SUMMARY OF THE INVENTION

An objective of the present invention is to provide a lock with a clutching function to allow free rotation of the outside handle while providing a simplified structure to allow easy assembling procedures.

A lock in accordance with the present invention comprises a body, a latch bolt mounted in the body, a wheel pivotally mounted in the body and operable to retract the latch bolt from an extended position to a retracted position, an outside spindle adapted to be mounted to an outside handle, a spring, a locking plug, and a push member mounted on the locking plug.

The wheel includes a through-hole defined by a circumferential wall. The outside spindle includes a front end having an extension. The extension is not in contact with the circumferential wall of the through-hole of the wheel. The spring is mounted in the outside handle for biasing the front end of the outside spindle into the through-hole of the first wheel, allowing joint rotation of the wheel and the outside spindle. The locking plug is mounted in the body and movable between an unblocking position allowing retraction operation of the latch bolt and a blocking position not allowing retraction operation of the latch bolt.

When the locking plug is in the unblocking position, the front end of the outside spindle is engaged with the wheel to allow joint rotation of the outside spindle and the wheel. When the locking plug is moved from the unblocking position to the blocking position, movement of the push member pushes the front end of the outside spindle away from the through-hole of the wheel such that the front end of the outside spindle is disengaged from the circumferential wall of the through-hole of the wheel, thereby disengaging the outside spindle from the wheel.

Preferably, the lock further comprises another wheel pivotally mounted in the body and adapted for cooperating with an inside spindle. This wheel is operable to retract the latch bolt from the extended position to the retracted position. A spacer ring is mounted between the two wheels and includes an opening. The front end of the push member extends through the opening of the spacer ring to a position between the two wheels.

Preferably, the extension of the outside spindle is remained in and not in contact with the circumferential wall defining through-hole of the wheel when the locking plug is in the blocking position.

In an embodiment, the push member is a member releasably mounted to the locking plug. The locking plug includes a recess. The push member includes a rear end mounted in the recess and a front end having an inclined face for pressing against and thus moving the extension of the outside spindle.

Preferably, the front end of the push member is arrow-shaped.

Preferably, the push member extends in a direction transverse to the longitudinal direction of the outside spindle.

Preferably, the extension of the outside spindle is conic.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring toFIGS. 1 through 3, a lock in accordance with the present invention comprises an inside handle assembly5, an outside handle assembly6, and a body7between the inside and outside handle assemblies5and6.

The inside handle assembly5includes an inside handle51and an inside spindle53mounted to an end52of the inside handle51. The outside handle assembly6includes an outside handle61and an outside spindle63mounted to an end62of the outside handle61. The inside handle assembly5and the outside handle assembly6are assembled together and respectively fixed to two sides of the body7by bolts65and mounting rods55with screw holes551. The inside and outside spindles53and63are square in this embodiment.

The body7is mounted in a groove or compartment90in a door9and includes a case71and a lid719for covering the case71. The case71includes an outer end face711having three openings712,713, and714into which a latch bolt72, a dead bolt73, and an auxiliary bolt74are respectively mounted. The case71further includes a lateral side710having a hole715that is aligned with a hole716in the lid719that forms the other lateral side of the case71after assembly.

A wheel81is pivotably mounted in the hole715of the lateral side710of the case71and includes a square through-hole811through which the inside spindle53extends. Another wheel82is pivotably mounted in the hole716of the lid719and includes a square through-hole821through which the outside spindle63extends. Turning of either handle51,61causes pivotal movement of the associated wheel81,82. Each wheel81,82further includes a tooth812,822. Further, the wheels81and82are spaced from each other by a spacer ring87.

The latch bolt72includes a head722and a shank721extending from the head722through the opening712. The head722of the latch bolt72is normally biased by a spring (not labeled) to an extended, latching position outside the case71. A substantially U-shaped bracket724is mounted on the shank721of the latch bolt72and drivable by a lever link75or one of two drive members76.

The lever link75is mounted in the case71and pivotable about a pivot751. The lever link75includes an intermediate portion (not labeled) pivotally mounted around the pivot751, a first end752, and a second end753engaged with the bracket724of the latch bolt72. A lock core750is rotatably mounted in a hole717in the lateral side710of the case71and includes an actuating member754. In a case that the dead bolt73is in an extended, locking position, when the lock core750is turned by a key, the dead bolt73is firstly retracted. Further turning of the lock core750causes the actuating member754to engage with the first end752of the lever link75and to turn the lever link75. The bracket724is moved inward by the second end753of the lever link75, thereby retracting the latch bolt72.

The drive members76are mounted between the wheels81and82and spaced by the spacer ring87. Each drive member76includes a lug761for pushing the bracket724of the latch bolt72. A linking member78is also mounted in the case71and includes a first pin781on an end thereof and a second pin782on the other end thereof. The first pin781extends through a hole762in each lug761. A cam79is rotatably mounted to the lateral side710of the case71and engaged with the second pin782. The cam79includes a projection791.

When either wheel81,82is turned clockwise through operation of the associated handle51,61(seeFIG. 4), the tooth812,822of the wheel81,82pushes the first pin781clockwise, causing clockwise movement of the lug761, which, in turn, moves the bracket724inward, thereby retracting the latch bolt72.

On the other hand, when either wheel81,82is turned counterclockwise, the tooth812,822of the wheel81,82pushes against the projection791on the cam79, causing rotation of the cam79. The lug761of the drive member76is moved inward through transmission by the linking member78. Thus, the latch bolt72is retracted.

Also mounted in the case71and located adjacent to the wheel82is a locking plug77comprising two slots771and772in which two pivots773and774are slidably received. The locking plug77further includes a face770.

A pivotal member83is pivotally mounted to the lateral side710of the case71and includes an axle832and an actuating portion831. A thumb turn830is engaged with the pivotal member83to turn therewith. The actuating portion831is slidably received in a slot (not shown) in a shank731of the dead bolt73. When the pivotal member83is turned by turning the thumb turn830, the dead bolt73is moved between an extended, locking position and a retracted, unlocking position.

A cam86includes a longitudinal hole861for securely engaging with the axle832of the pivotal member83, allowing joint rotation of the cam86and the pivotal member83. A follower plate84is mounted in the case70and connected to the locking plug77so that upward/downward movement (as viewed fromFIG. 1) of the follower plate84causes leftward/rightward movement (as viewed fromFIG. 1) of the locking plug77. When the thumb turn830is turned while the dead bolt73remains in the retracted, locking position, the pivotal member83pivots, and the actuating portion831drives the follower plate84to move upward/downward, thereby moving the locking plug77leftward/rightward.

The second pin782of the linking member78extends through a slot851in a rocker arm85that is pivotally mounted in the case71at a first end852thereof. A second end853of the rocker arm85abuts against the cam86that turns jointly with the pivotal member83. When the dead bolt73is in the extended, locking position, turning of the inside handle51causes turning of the wheel81, which, in turn, causes the cam79to turn clockwise. The second end851of the rocker arm85presses against the cam86and thus turns the pivotal member83to retract the dead bolt73into the case71, achieving the unlocking function. Of course, turning of the inside handle51also unlatches the latch bolt72.

The thumb turn830is movable between an unblocking position (in which the follower plate84is in its upper position, the locking plug77is in its right, unblocking position not engaging with the tooth812,822of the associated wheel81,82, and the dead bolt73is in its retracted state, seeFIG. 1), a blocking position (in which the follower plate84is in its lower position, the locking plug77is in its left, blocking position engaging with the tooth812,822of the associated wheel81,82, and the dead bolt73is in its retracted state), and a locking position (in which the follower plate84is in its lower position, the locking plug77is in its left, blocking position engaging with the tooth812,822of the associated wheel81,82, and the dead bolt73is in its extended state).

Referring toFIG. 3, a spring64is mounted behind the outside spindle63for biasing a front end641of the outside spindle63into the through-hole821of the wheel82, allowing transmission of torque resulting from turning of the outside handle61for the purposes of retracting the latch bolt72.

Still referring toFIG. 3, a spring54is mounted behind the inside spindle54for biasing a front end (not labeled) of the inside spindle53into the through-hole811of the wheel81, allowing transmission of torque resulting from turning of the inside handle51for the purposes of retracting the latch bolt72.

The above structure and operations are conventional. Of more importance, the outside spindle63is disengaged from the wheel82when in a locked state. Further, engagement or disengagement of the outside spindle63with or from the wheel82is reliable.

Referring toFIGS. 2 and 3, a push member4is mounted to the face770of the locking plug77. In the illustrated embodiment, the push member4is a separate member fixed to the face770of the locking plug77and movable in the moving direction of the latch bolt72together with the locking plug77. Alternatively, the push member4may be an integral member projecting from the face770of the locking plug77.

The push member4includes a front end42and a rear end41. The rear end41of the push member5is engaged in a recess775in the face770of the locking plug77. The front end42of the push member4extends through an opening871of the spacer ring87to a position between the wheels81and82. The front end42of the push member4includes at least one inclined face421. In the illustrated embodiment, the front end42of the push member4is arrow-shaped having two opposed inclined faces421.

Further, the front end631of the outside spindle63includes an extension632extending along a longitudinal direction of the outside spindle63. The extension632has a reduced diameter and is thus not in contact with a circumferential wall defining the through-hole821of the wheel82. In the illustrated embodiment, the extension632and has a conic section with a conic face (not labeled) at a front end thereof. When the outside spindle63is biased by the spring64into the through-hole821of the wheel82, the conic face of the extension632is stopped and thus positioned by the inclined face421of the push member4.

Referring toFIGS. 3 and 4, when the lock is in an unlocked state, operation of either handle51,61causes rotation of the wheel81,82, resulting in retraction of the latch bolt72, as mentioned above.

Referring toFIGS. 5 and 6, when the locking plug77is moved leftward for blocking purposes, the push member4fixed on the face770of the locking plug77moves together with the locking plug77in the moving direction of the latch bolt72. At this time, since the push member4and the extension632of the outside spindle63are in contact with each other and extend in directions transverse to each other, inward movement of the push member4causes the outside spindle63to move away from the through-hole821of the wheel82in the longitudinal direction of the outside spindle63. Thus, the outside spindle63is disengaged from the wheel82, as the conic face of the extension632is not in contact with the circumferential wall defining the through-hole821of the wheel82.

Referring toFIGS. 6 and 7, after the front end631of the outside spindle63is disengaged from the wheel82, transmission of the torque from the outside spindle63to the wheel82is impossible. Thus, turning of the outside handle61is idle when the lock is in the locked state. In other words, the outside handle61pivots idly, preventing the internal elements of the lock from being damaged in a case that a relatively large force is applied to the outside handle61.

The lock in accordance with the present invention is simplified in structure and thus allows easier assembly. Operation of the push member4and the outside spindle63is reliable by the provision of the inclined face421of the push member4and the conic face of the extension632of the outside spindle63. Nevertheless, the present invention is not limited to the arrangement of the inclined face421of the push member4and the conic face633of the extension632of the outside spindle63shown in the figures. Namely, other equivalent arrangements with different shapes and/or different engaging orientations are allowed.

Although a specific embodiment has been illustrated and described, numerous modifications and variations are still possible without departing from the essence of the invention. The scope of the invention is limited by the accompanying claims.