Combination lock with key opening mechanism

A combination lock comprises a first shackle, dials, a spring loaded member biased against the innermost dial, a second shackle comprising an inner arm, a moveable block pivotably coupled to the inner arm and including a spring and an opposite T-shaped slot, and a key opening mechanism aligned with the moveable block and comprising a shaft and a cross member. Inserting a key into the mechanism and turning the key will rotate the shaft and the cross member until the cross member is aligned with an opening of the slot such that pressing the second shackle will cause the inner arm to counterclockwise pivot about the member, move the moveable block outwards to compress the spring and dispose the cross member in the opening, and disengage the second shackle from the first shackle.

FIELD OF THE INVENTION

The present invention relates to combination locks and more particularly to such a combination lock with a key opening mechanism so that a person may use a key to work the key opening mechanism that opens the lock if such is required due to, for example, forgetting of the correct combination.

BACKGROUND OF THE INVENTION

There have been numerous suggestions in prior patents about combination lock with a key opening mechanism so that a person may use a key to work the key opening mechanism that opens the lock if such is required due to, for example, forgetting of the correct combination. Such prior mechanisms, however, are relatively complex in constructions, costly to manufacture, trouble-prone, and unreliable in use. Thus, the need for improvement still exists.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a combination lock with a key opening mechanism so that a person may use a key to work the key opening mechanism that opens the lock if such is required due to, for example, forgetting of the correct combination.

To achieve the above and other objects, the present invention provides a combination lock comprising a housing comprising a cover having a plurality of first openings, and a base matingly coupled to the cover, the base including a recess, a first cavity besides the recess, a second cavity aligned with and being in communication with the first cavity, and an extended first shackle; a dial assembly provided in the recess and comprising a plurality of parallel dials partially projected from the first openings of the cover, each dial having a plurality of distinct indicia formed on its outer surface, and a spring loaded member biased against the innermost dial, the spring loaded member being moveable in response to a correct combination of the dials; a second shackle comprising an outer arm matingly engaged with an end of the first shackle when the lock is locked, an inner, intermediate convex portion biased against the spring loaded member, an inner arm extended above the second cavity, a hole formed at one end of the inner arm, and an outer, intermediate trigger portion; a moveable block provided in the second cavity and comprising a top pin inserted into the hole for forming a pivotal coupling to the second shackle, an aperture having a blind end, a resilient member received in the aperture and resiliently confined by the second cavity, and a T-shaped slot opposite the aperture, the slot having a second opening; and a key opening mechanism provided in the first cavity and comprising a keyhole, a protruded, rotatable shaft opposite the keyhole, the shaft being disposed across the second opening when the lock is locked, and a cross member formed at an end of the shaft, the cross member being disposed in the slot when the lock is locked, whereby in response to a correct combination of the dials pressing the trigger portion will cause the convex portion to compress the spring loaded member, counterclockwise pivot the outer arm about the pin, and disengage the outer arm from the first shackle; and inserting a key into the keyhole and turning the key will rotate both the shaft and the cross member until the cross member is aligned with the second opening such that subsequently pressing the trigger portion will cause the inner arm to counterclockwise pivot about the spring loaded member, move the moveable block outwards to compress the resilient member and move the second opening until the cross member disposes therein, and disengage the outer arm from the first shackle.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring toFIGS. 1 and 2, there is shown a combination lock constructed in accordance with a preferred embodiment of the invention comprising a housing10, a dial assembly20provided in the housing10, a second shackle30extended from the housing10, a moveable block40provided in the housing10, and a key opening mechanism50provided in the housing10. Each component will be described in detailed below.

The housing11comprises a cover11having a plurality of (three as shown) rectangular openings111, and a base12matingly coupled to the cover11, the base12including a seat with the dial assembly20anchored therein, two opposite first walls121besides the dial assembly20, two opposite second walls122perpendicular to the first walls121to define a first cavity125and a second cavity126therein in which the first cavity125is aligned with and is in communication with the second cavity126, and a first shackle123extended from the base12, the first shackle123having an open end124.

The dial assembly20comprises a plurality of (three are shown) parallel dials partially projected from the openings111, each dial having ten distinct indicia formed on its outer surface, and a coil spring21compressed between the innermost dial and a plate22which may move in response to a correct combination of the dial assembly20.

The second shackle30comprises an outer arm31shaped to matingly engage with the open end124when the lock is locked, an inner, intermediate convex portion32biased against the plate22, an inner arm33extended over the second wall122by a small distance as to be able to freely move above, a hole34in one end of the inner arm33, and an outer, intermediate trigger portion35.

The parallelepiped moveable block40is provided in the second cavity126and comprises a top pin42inserted into the hole34such that the second shackle30is able to pivot about the pin42, a cylindrical aperture41having a blind end, a coil spring411received in the aperture41and resiliently confined by the second wall122, and a T-shaped slot43opposite the aperture41, the slot43having an opening44.

The cylindrical key opening mechanism50is provided in the first cavity125and comprises a keyhole51having an opening511, a protruded, rotatable shaft512opposite the opening511, the shaft512being disposed across the opening44in a locked position of the lock, and a cross member513formed at an end of the shaft512, the cross member513being disposed in the slot43in the locked position of the lock.

Opening operations of the combination lock will be described in detailed below.

Referring toFIG. 3, there is shown a locked position of the combination lock in which the spring21is expanded to push the second shackle30outwards with the outer arm31matingly engaged with the open end124. That is, pressing the trigger portion35will not compress the spring21to open the combination lock since the combination is not correct.

Referring toFIG. 4, in response to a correct combination of the dial assembly20pressing the trigger portion35will cause the convex portion32to compress the spring21due to a counterclockwise pivotal operation of the outer arm31(i.e., the second shackle30) about the pin42. As a result, the outer arm31is disengaged from the open end124for opening the combination lock.

Referring toFIG. 5, there is shown the locked combination lock in which the cross member513is confined in the slot43(i.e., the moveable block40is immoveable). As such, pressing the trigger portion35still cannot compress the spring21to open the combination lock since the combination is not correct.

Referring toFIG. 6, in a case of forgetting of the correct combination a user may insert a key60into the keyhole51. Next, turn the key60to work the key opening mechanism50to cause the shaft512and thus the cross member513to rotate. Once the cross member513is aligned with the opening44, pressing the trigger portion35will cause the inner arm33to counterclockwise pivot about the spring21(i.e., the convex portion32). And in turn, the pin42(i.e., the moveable block40) moves toward the second wall122to compress the spring411due to the pivotal coupling of the pin42and the inner arm33at the hole34. At the same time, the opening44moves outwardly for permitting the cross member513to dispose therein. As an end, the outer arm31is disengaged from the open end124for opening the combination lock.