Locking device

A locking device includes a lock and a key. The lock includes a housing, a cylindrical core inserted into and rotatable relative to the housing, and a limiting member that is mounted movably between the housing and the cylindrical core to permit or prevent the relative rotation between the housing and the cylindrical core and that extends into a helical keyway formed in the cylindrical core. The key has a helical blade capable of being inserted into the helical keyway to access the limiting member, so as to move the limiting member to permit the relative rotation between the cylindrical core and the housing.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority of Taiwanese Application No. 103117128, filed on May 15, 2014.

FIELD OF THE INVENTION

The invention relates to a locking device, more particularly to a lock and a key.

BACKGROUND OF THE INVENTION

A conventional lock includes a housing, a central cylinder and a plurality of tumbler members. The central cylinder is inserted into the housing, is rotatable relative to the housing, and has a straight keyway that is formed through an insertion end thereof. Each of the tumbler members is mounted movably between the housing and the central cylinder, extends into the keyway, and is operable to move between a holding position, where the tumbler member is inserted into both of the housing and the central cylinder to prevent the relative rotation between the housing and the central cylinder, and a released position, where the tumbler member is retracted into one of the housing and the central cylinder to permit the relative rotation between the housing and the central cylinder.

Each of the tumbler members can be accessed by a straight key blade that is inserted into the keyway, so as to be driven to move to the released position to permit the relative rotation between the housing and the central cylinder. However, the conventional lock is easily picked since a picking tool may be easily inserted into the straight keyway to access the tumbler members.

SUMMARY OF THE INVENTION

Therefore, an object of the present invention is to provide a pick-resistant locking device.

Accordingly, a locking device of the present invention includes a lock and a key. The lock includes a housing, a cylindrical core and a tumbler unit. The housing includes a housing body having an inner surrounding surface that defines an inner space, and a limiting groove that is formed in the inner surrounding surface, and that communicates spatially with the inner space. The cylindrical core extends along a core axis into the housing, is rotatable relative to the housing about the core axis, and has an insertion end, a helical keyway and a retaining groove. The insertion end is retained in the inner space of the housing body. The helical keyway is formed in an outer surrounding surface of the cylindrical core, and extends through the insertion end to form an opening of the insertion end. The retaining groove is formed in the outer surrounding surface of the cylindrical core, and communicates spatially with the helical keyway. The tumbler unit includes a limiting member and a resilient member. The limiting member is mounted to the cylindrical core, is movable relative to the cylindrical core along a limiting axis of the cylindrical core, and has a main body, a limiting projection and a driven section. The main body extends into the retaining groove. The limiting projection projects away from the cylindrical core, and is aligned with the limiting groove in the direction of the limiting axis when the cylindrical core is at a locked position. The limiting projection engages fittingly the limiting groove to prevent the relative rotation between the cylindrical core and the housing when the limiting member is at an engaged position. The limiting projection is disengaged from the limiting groove to permit the relative rotation between the cylindrical core and the housing when the limiting member is at a disengaged position. The driven section extends into the helical keyway. The resilient member is connected to the limiting member for biasing resiliently the limiting member to the engaged position when the cylindrical core is at the locked position, so as to prevent the relative rotation between the cylindrical core and the housing. The key has a grip section for being held, and a blade section that is connected to the grip section. The blade section includes a helical blade capable of being inserted fittingly into the helical keyway via the opening of the insertion end of the cylindrical core to access the driven section of the limiting member when the cylindrical core is at the locked position, so as to drive movement of the limiting member to the disengaged position to permit the relative rotation between the cylindrical core and the housing.

Another object of the present invention is to provide a pick-resistant lock.

Accordingly, a lock of the present invention includes a housing, a cylindrical core and a tumbler unit. The housing includes a housing body that has an inner surrounding surface defining an inner space, and a limiting groove formed in the inner surrounding surface and communicating spatially with the inner space. The cylindrical core extends along a core axis into the housing, is rotatable relative to the housing about the core axis, and has an insertion end, a helical keyway and a retaining groove. The insertion end is retained in the inner space of the housing body. The helical keyway is formed in an outer surrounding surface of the cylindrical core, and extends through the insertion end to form an opening of the insertion end. The retaining groove is formed in the outer surrounding surface of the cylindrical core, and communicates spatially with the helical keyway. The tumbler unit includes a limiting member and a resilient member. The limiting member is mounted to the cylindrical core, is movable relative to the cylindrical core along a limiting axis of the cylindrical core, and has a main body, a limiting projection and a driven section. The main body extends into the retaining groove. The limiting projection projects away from the cylindrical core, and is aligned with the limiting groove in the direction of the limiting axis when the cylindrical core is at a locked position. The limiting projection engages fittingly the limiting groove to prevent the relative rotation between the cylindrical core and the housing when the limiting member is at an engaged position. The limiting projection is disengaged from the limiting groove to permit the relative rotation between the cylindrical core and the housing when the limiting member is at a disengaged position. The driven section extends into the helical keyway. The resilient member is connected to the limiting member for biasing resiliently the limiting member to the engaged position when the cylindrical core is at the locked position, so as to prevent the relative rotation between the cylindrical core and the housing. A blade member is capable of being inserted into the helical keyway via the opening of the insertion end of the cylindrical core to access the driven section of the limiting member when the cylindrical core is at the locked position, so as to drive movement of the limiting member to the disengaged position to permit the relative rotation between the cylindrical core and the housing.

Yet another object of the present invention is to provide a key for use with a pick-resistant lock.

Accordingly, a key of the present invention is adapted for use with a lock. The lock includes a housing, a cylindrical core that extends rotatably into the housing and that has a helical keyway, and a limiting member that is mounted movably between the housing and the cylindrical core. The limiting member has a driven section that extends into the helical keyway, and is movable between an engaged position where the relative rotation between the housing and the cylindrical core is prevented, and a disengaged position where the relative rotation between the housing and the cylindrical core is permitted. The key includes a grip section for being held, and a blade section connected to the grip section and including a helical blade. The helical blade is adapted to be inserted into the helical keyway to access the driven section of the limiting member, so as to drive movement of the limiting member to the disengaged position to permit the relative rotation between the housing and the cylindrical core.

DETAILED DESCRIPTION OF THE EMBODIMENT

As shown inFIG. 1, an embodiment of a locking device according to the present invention includes a lock100and a key600.

Referring further toFIG. 2, the lock100includes a housing1, a cylindrical core2and three tumbler units3. The housing1includes a tubular housing body10and a pair of positioning rings13. The housing body10has an inner surrounding surface11that defines an inner space111, and three limiting grooves12(only two are visible inFIG. 1) that are formed in the inner surrounding surface11, and that communicate spatially with the inner space111. The positioning rings13are mounted in the housing body10, and are disposed respectively at opposite ends of the inner space111.

The cylindrical core2extends along a core axis (A), and is inserted into both of the positioning rings13for being positioned relative to the housing body10of the housing1. The cylindrical core2is rotatable relative to the housing1about the core axis (A), and has an insertion end22, a mount end25, two helical keyways21, three retaining grooves23and three installation grooves24.

The insertion end22is retained in one of the positioning rings13, and cooperates with the one of the positioning rings13to define an insertion groove4. The mount end25is opposite to the insertion end22along the core axis (A), and is disposed outwardly of the housing1for being mounted with a latch piece (not shown).

The helical keyways21are formed in an outer surrounding surface of the cylindrical core2, and are angularly spaced apart from each other about the core axis (A). Each of the helical keyways21extends through the insertion end22of the cylindrical core2to form an opening of the insertion end22(i.e., the insertion end22is formed with two openings corresponding respectively to the helical keyways21).

The retaining grooves23are formed in the outer surrounding surface of the cylindrical core2, and are spaced apart from each other along the core axis (A). Each of the retaining grooves23extends in the circumferential direction of the cylindrical core2, and communicates spatially with both of the helical keyways21.

The installation grooves24are formed in the outer surrounding surface of the cylindrical core2, and correspond respectively to the retaining grooves23. Each of the installation grooves24extends in the radial direction of the cylindrical core2, and communicates spatially with the corresponding one of the retaining grooves23.

The tumbler units3are mounted to the cylindrical core2, and correspond respectively to the retaining grooves23. For simplification, one of the tumbler units3will be described in the following.

The tumbler unit3includes a limiting member31and a resilient member32. The limiting member31is movable relative to the cylindrical core2along a limiting axis (L) of the cylindrical core2, and has a main body311, a limiting projection312and two guide blocks313. In this embodiment, the limiting axis (L) extends in the radial direction of the cylindrical core2. The main body311extends into the correspond one of the retaining grooves23such that the limiting member31is prevented from moving along the core axis (A) relative to the cylindrical core2. The limiting projection312projects away from the cylindrical core2from the main body311, and is aligned with a respective one of the limiting grooves12of the housing1in the radial direction of the cylindrical core2when the cylindrical core2is at a locked position relative to the housing1(seeFIGS. 3 and 6). The main body311is C-shaped, and has two driven sections314extending respectively into the helical keyways21, and cooperatively defining an extending space310therebetween. Each of the guide blocks313projects from a respective one of the driven sections314and into the extending space310.

When the cylindrical core2is at the locked position, the limiting member31is movable in the radial direction of the cylindrical core2between an engaged position (seeFIG. 3), where the limiting projection312engages fittingly the respective one of the limiting grooves12to prevent the relative rotation between the cylindrical core2and the housing1, and a disengaged position (seeFIG. 6), where the limiting projection312is disengaged from the respective one of the limiting grooves12to permit the relative rotation between the cylindrical core2and the housing1. In this embodiment, the positioning rings13define an annular gap between the housing body10and the cylindrical core2for permitting the radial movement of the limiting member31of each of the tumbler units3.

The resilient member32is installed in the installation groove24corresponding to the corresponding one of the retaining grooves23, and has opposite ends abutting respectively against the limiting member31and the cylindrical core2for biasing resiliently the limiting member31away from the cylindrical core2. That is, the resilient member32biases resiliently the limiting member31to the engaged position to prevent the relative rotation between the cylindrical core2and the housing1when the cylindrical core2is at the locked position. In this embodiment, the resilient member32is configured as a compression spring.

The key600has a blade section60, a grip section for being held, and a connecting section64interconnecting the blade section60and the grip section66.

The blade section60has a double-helix structure that includes two helical blades61corresponding respectively to the helical keyways21of the cylindrical core2. Each of the helical blades61has an outer helical surface63that extends in an extending direction of the helical blade61, and that faces radially and outwardly to serve as a guide surface, and a continuous guide groove65that is formed in the outer helical surface63.

Referring toFIG. 4, to clearly describe, one of the helical blades61is unrolled and stretched. The guide groove65of the helical blades61substantially extends along the outer helical surface63of the helical blade61. At least a portion of the guide groove65does not extend in the helically-extending direction of the outer helical surface63.

Each of the helical blades61is able to be inserted fittingly into the corresponding one of the helical keyways21via the corresponding opening to access the corresponding driven section314of the limiting member31of each of the tumbler units3extending into the corresponding helical keyway21. It is noted that the width (w1) (seeFIG. 4) of the guide groove65of each of the helical blades61is equal to or greater than the width (w2) (seeFIG. 3) of the corresponding guide block313of the limiting member31of each of the tumbler units3disposed in the corresponding helical keyway21.

Initially, the cylindrical core2is at the locked position, and the limiting member312of each of the tumbler unit3is at the engaged position to prevent the relative rotation between the cylindrical core2and the housing1. At this time, the latch piece is retained in a locking groove (not shown).

Referring toFIG. 2, to remove the latch piece from the locking groove, the blade section60of the key600is first inserted into the insertion groove4, and is therefore limited to rotate within the insertion groove4until distal ends of the helical blades61are respectively registered with the openings of the insertion end22of the cylindrical core2.

Then, the helical blades61are inserted respectively into the helical keyways21and through the extending space310of the limiting member31of each of the tumbler units3, and the guide grooves65of the helical blades61are engaged slidably and respectively with the guide blocks313of the limiting member31of each of the tumbler units3. Referring toFIG. 5, during the insertion movement of the blade section60, the limiting members31of the tumbler units3are in turn driven to move in the radial direction of the cylindrical core2between the engaged position and the disengaged position. Two groove-defining surfaces of the blade section60that respectively define the guide grooves65of the helical blades61are configured to drive all of the limiting members31to move to the disengaged position when the helical blades61are completely and respectively inserted into the keyways21. As a result, the latch piece can be removed from the locking groove by turning the grip section66of the key600to rotate the cylindrical core2relative to the housing1.

To drive the latch piece back to engage the locking groove, the grip section66of the key600is turned to drive rotation of the cylindrical core2relative to the housing1. It is noted that, the limiting projection312of each of the tumbler units3is misaligned with the corresponding limiting groove12when the cylindrical core2leaves the locked position, so that the limiting projection312of each of the tumbler units3abuts against the inner surrounding surface11of the housing body10to prevent the radial movement of the limiting member31of the tumbler units3, and to thereby limit the movement of the blade section60along the core axis (A) relative to the cylindrical core2until the cylindrical core2is rotated back to the locked position, where the latch piece engages the locking groove, and at least one of the limiting members31moves back to the engaged position. Then, the relative rotation between the cylindrical core2and the housing1is prevented, and the helical blades61of the blade segment60can be driven to disengage respectively from the helical keyways21.

It is noted that the lock100may include less than three or more than three tumbler units3, and the cylindrical core2correspondingly has the same number of the retaining grooves23and the same number of the installation grooves24for being mounted respectively with the tumbler units3. Therefore, the configuration of the guide groove65of each of the helical blades61needs to be modified according to the number of the tumbler units3. Moreover, the blade segment60of the key600may include only one or more than two helical blades61, and the cylindrical core2correspondingly has one or more than two helical keyways21. The limiting member31of each of the tumbler units3may therefore have at least one driven section314that extends into one of the helical keyways21to be driven when the helical blades61are inserted respectively into the helical keyways21.

It is further noted that each of the helical blades61is adjustable in geometry and shape, such as cross-sectional area, thickness, angle and extending direction, with the helical keyways21being correspondingly modified. The locations of the tumbler units3are also adjustable with the configuration of the guide groove65of each of the helical blades61being correspondingly modified.

To sum up, the lock100of the locking device of this invention has the helical keyways21and the limiting members31each extending into the helical keyways21to be driven. Since a picking tool must be inserted into at least one of the helical keyways21to access all of the limiting members31and to drive movements of all of the limiting members31, it is difficult to pick the lock100unless the picking tool is configured like the helical blade61of the key600of this invention.