DETAILED DESCRIPTION

[0030] FIGS. 1-9 illustrate a locking mechanism 10 according to an embodiment of the invention. With reference to FIGS. 1-3 , the locking mechanism 10 includes an outer housing 14 , a lock cylinder 18 received within the housing 10 , and a sleeve 22 also received with the housing 10 and surrounding at least a portion of the lock cylinder 18 . The embodiment illustrated in FIGS. 1-9 also includes an intermediate engagement member in the form of a clutch disk 26 , and an actuator element 30 .

[0031] The housing 14 provides a generally cylindrical, open-ended cavity 32 and defines a central axis 34 . In this regard, the housing 14 can take any shape within which the lock cylinder 18 can be received, and in some embodiments (such as that shown in the figures) is generally round. The housing 14 can enclose any amount of the lock cylinder 18 desired, such as by surrounding the length of the lock cylinder as shown in the figures.

[0032] The housing 14 can include outwardly extending mounting protrusions 36 that are securable to, among other things, a vehicle door or vehicle steering column that is to be lockably secured by the locking mechanism 10 . The mounting protrusions 36 can take a variety of different forms and are generally determined by the device or mechanism (e.g. a vehicle part or assembly) to which the locking mechanism 10 is to be secured.

[0033] A cylinder-receiving end 38 of the housing 14 includes an internal lip 42 in the housing 14 for limiting travel of the sleeve 22 toward the cylinder-receiving end 38 of the housing 14 . In other embodiments, sleeve travel in this direction can be limited in any other manner desired, such as by one or more bosses, pins, neck portions, and other features of the housing 14 (as well as element attached to the housing 14 ), each of which falls within the spirit and scope of the present invention.

[0034] For purposes that will be described in greater detail below, the housing 14 also includes a cam surface 46 extending radially into the cavity 32 and facing axially away from the receiving end 38 . The cam surface 46 defines one or more axially extending cam projections 50 within the cavity 32 . In some embodiments of the invention, the cylinder-receiving end 38 further includes an outer groove 51 that is configured to engage an end cap 52 of the locking mechanism 10 . The end cap 52 can be shaped to generally overlie and surround the cylinder-receiving end 38 of the housing 14 when engaged with the outer groove 51 . Alternatively, the end cap 52 (where used) can be directly or indirectly attached to the housing 14 in any other conventional manner.

[0035] Opposite the cylinder-receiving end 38 of the housing 14 is a retaining end 54 . The retaining end 54 of the housing 14 can be the same size as the cylinder-receiving end 38 or can have any other size desired, and in some embodiments (such as that illustrated in the figures) is somewhat diametrically enlarged with respect to the receiving end 38 of the housing 14 .

[0036] For purposes that will be described below, the retaining end 54 of the housing 14 illustrated in the figures includes a radially outwardly extending boss 58 that surrounds a through hole 62 communicating with the cavity 32 . The through hole 62 receives a pin 64 that extends radially into the cavity 32 . Although the boss 58 is not required, the boss 58 provides strength for the housing 14 adjacent to the pin 64 . The retaining end 54 can also include one or more axially and circumferentially extending notches or cutouts 66 that define a return-spring reaction tab 68 on the housing 14 .

[0037] The lock cylinder 18 is received within the cavity 32 and can take any conventional lock cylinder form. By way of example, the lock cylinder 18 in the illustrated embodiment includes a barrel portion 78 that houses a plurality of lock tumblers 82 . Other types of tumbler or pin-type lock cylinders can be employed in conjunction with the present invention as desired. Although the lock cylinder 18 can have any shape, the lock cylinder 18 illustrated in the figures includes an end flange 86 that seats against the internal lip 42 in the housing 14 when the lock cylinder 18 is inserted into the cavity 32 . The internal lip 42 assists in properly positioning the lock cylinder 18 with respect to the housing 14 , and can be replaced with any number of other elements and structure capable of performing the same function (including those described above with reference to the internal lip 42 ).

[0038] At one end of the lock cylinder 18 is a key slot 90 that receives a key (not shown). When an appropriate key is inserted into the lock cylinder 18 , the lock tumblers 82 engage the key and move within the barrel portion 78 to predetermined positions such that the lock cylinder 18 is placed in an unlocked state. If no key or an incorrect key is inserted into the lock cylinder 18 , one or more of the lock tumblers 82 will be improperly positioned, and the lock cylinder 18 will remain in a locked state.

[0039] In some embodiments of the present invention, the lock cylinder 18 also includes a sidebar 94 that radially extends from the barrel portion 78 when the lock cylinder 18 is in the locked state. In such embodiments, the sidebar 94 can be operatively coupled to the lock tumblers 82 such that when the appropriate key is inserted and the lock tumblers 82 move to their predetermined positions, the sidebar 94 moves radially inwardly with respect to the barrel portion 78 to a retracted position corresponding to the unlocked state of the lock cylinder 18 . In alternate embodiments of the present invention, such a sidebar is not employed. Instead, when the lock cylinder 18 is in the locked state, one or more of the tumblers 82 extend radially outwardly from the lock cylinder 18 to engage a housing or other adjacent element and to thereby prevent rotation of the lock cylinder 18 . When an appropriate key is inserted into the lock cylinder 18 , all of the tumblers are retracted into the barrel portion 78 to permit rotation of the lock cylinder 18 . The specific operation of and interaction between the key and the lock tumblers 82 (as well as between the lock tumblers 82 and the sidebar 94 , where employed) are well known in the art and are therefore not discussed further herein. While one specific type of lock cylinder 18 is illustrated in the drawings, substantially any type of rotatable lock cylinder is suitable for use with the present invention.

[0040] The lock cylinder 18 in the illustrated embodiment also has an axially extending boss 98 (substantially aligned with the central axis 34 when the lock cylinder 18 is received within the cavity 32 ) that helps to maintain the position of the lock cylinder 18 in the locking mechanism 10 . The boss 98 can have any shape desired, such as the generally cylindrical shape shown in the figures. With continued reference to the illustrated embodiment, one or more dogs 102 extend axially away from the barrel portion 78 and radially outwardly from the boss 98 . As illustrated, two dogs 102 a , 102 b are provided at substantially diametrically opposed positions, one of which ( 102 a ) is substantially radially aligned with the sidebar 94 . The dog 102 a is configured to extend radially beyond the barrel portion 78 such that the dog 102 a and the sidebar 94 extend from the barrel portion (substantially the same distance in the illustrated embodiment) when the lock cylinder 18 is in the locked condition and the sidebar 94 is extended. In some embodiments, the boss 98 includes a circumferential groove 100 extending around its distal end for receiving a clip 170 that retains the elements of the locking mechanism 10 in their proper relative positions.

[0041] The sleeve 22 in the illustrated embodiment is generally tubular and is received within the annular space formed between the housing 14 and the lock cylinder 18 when the lock cylinder 18 is inserted into the cavity 32 . An outer surface 110 of the sleeve 22 faces the housing 14 , and an inner surface 114 of the sleeve 22 faces the barrel portion 78 of the lock cylinder 18 . The sleeve 22 has at least one aperture or recess 118 within which tumblers 82 of the lock cylinder 18 can be received. The sleeve 22 can have a single aperture or recess 118 in those embodiments of the present invention having one set of tumblers 82 located in one circumferential position in the lock cylinder 18 . Alternatively, the sleeve 22 can have multiple apertures or recesses 118 , such as where multiple sets of tumblers 82 are located in different circumferential locations in the lock cylinder 18 . For example, the sleeve 22 in the illustrated embodiment has two diametrically opposed elongated slots 118 corresponding to two sets of tumblers 82 .

[0042] The apertures or recesses 118 in the sleeve 22 can have substantially any shape and can be positioned substantially anywhere along the sleeve 22 . In some embodiments of the invention, the apertures or recesses 118 may be excluded altogether. The shape and positioning of the apertures or recesses 118 is largely dependent upon the configuration of the lock cylinder 18 . By way of example only, the sleeve 22 in the illustrated embodiment has two axially elongated slots 118 for receiving the lock tumblers 82 that extend beyond the barrel portion 78 when the lock cylinder 18 is in the locked state. When the tumblers 82 are extended into the elongated slots 118 , the tumblers 82 prevent rotation of the lock cylinder 18 with respect to the sleeve 22 . The axially elongated slots 118 can also perform drainage functions for the locking mechanism 10 .

[0043] One end of the sleeve 22 includes a generally annular cam surface 122 that engages the cam surface 46 of the housing 14 . The cam surface 122 provides one or more axial cam recesses 126 that are configured to receive one or more cam projections 50 of the housing 14 . The other end of the sleeve 22 includes a generally annular clutch-engaging surface 128 that slidingly engages the clutch disk 26 , depending upon the state (e.g. locked or unlocked) of the lock cylinder 18 . As will be described further below, the “clutch” portion of the lock mechanism is provided by the sleeve 22 and the disk 26 , which selectively drivingly or slidingly engage one another.

[0044] For those embodiments of the preset invention employing a sidebar 94 as described above, the sleeve 22 can also include an aperture or recess 130 for receiving the sidebar 94 . As with the apertures or recesses 118 of the sleeve 22 , the aperture or recess 130 for the sidebar 94 can have any shape and location suitable for receiving the sidebar 94 . In the illustrated embodiment for example, the aperture or recess 130 is an axially extending groove 130 recessed with respect to the inner surface 114 for receiving the sidebar 94 when the sidebar 94 is extended. In some embodiments of the invention, the engagement between the sidebar 94 and the aperture or recess 130 alleviates the need for engagement between the tumblers 82 and the apertures or recesses 118 . In this respect, some embodiments of the invention can include tumblers 82 that do not extend from the lock cylinder 18 regardless of the condition (e.g. locked or unlocked) of the lock cylinder 18 .

[0045] With continued reference to the illustrated embodiment of the present invention, the overall length of the sleeve 22 is selected such that when the end flange 86 of the lock cylinder 18 is engaged with the internal lip 42 of the housing 14 , the cam projections 50 are aligned with and received by the cam recesses 126 , and the dogs 102 a , 102 b of the lock cylinder 18 extend axially beyond the clutch-engaging surface 128 toward the retaining end 54 of the housing 14 (see FIG. 4 ).

[0046] The engagement member or clutch disk 26 can have any shape desired, dependent at least partially upon the shape and position of the boss 98 and the sleeve 22 . With reference to FIGS. 2 and 3 for example, the engagement member or clutch disk 26 is generally round, is received by the retaining end 54 of the housing 14 and includes a central aperture 134 that receives the boss 98 of the lock cylinder 18 . The clutch disk 26 can include two or more (e.g. four as illustrated) radially extending protrusions 138 that define substantially equally angularly spaced apart cutouts or notches 142 therebetween. In some embodiments, one side of the clutch disk 26 includes a substantially annular protrusion 146 that surrounds the central aperture 134 , while the other side of the clutch disk 26 includes one or more axial recesses 150 that extend radially outwardly from the central aperture 134 . In the illustrated embodiment for example, the clutch disk 26 includes two recesses 150 that are substantially diametrically opposed to each other (although other numbers and arrangements of such recesses 150 are possible depending at least in part upon the number and arrangement of the dogs 102 a , 102 b on the lock cylinder 18 ). The recesses 150 are adapted and configured to receive the dogs 102 a , 102 b of the lock cylinder 18 , such that rotational movement of the lock cylinder 18 is transmitted to the clutch disk 26 due to driving engagement between the dogs 102 a , 102 b , and the recesses 150 .

[0047] The actuator element 30 can perform a single function or can perform two or more functions. For example, the actuator element 30 can be employed to retain elements of the locking mechanism 10 in place, can be employed to connect the locking mechanism 10 to the device controlled thereby, and/or can be employed to assist in properly positioning the lock cylinder 18 within the locking mechanism 10 . In the illustrated embodiment, the actuator element 30 has at least some portion that is received by the retaining end 54 of the housing 14 and includes a central aperture 154 that receives the boss 98 of the lock cylinder 18 . The actuator element 30 can include an end wall 158 that defines the end of the locking mechanism 10 .

[0048] The actuator element 30 can also include one or more (e.g. three as illustrated) angularly spaced-apart dogs or projections 162 that extend axially inwardly with respect to the cavity 32 , as well as a protrusion 164 (e.g., an annular projection as shown in the figures) that also extends axially inwardly with respect to the cavity 32 . The axial dogs or projections 162 can take any shape desired, including rod-shaped or bar-shaped elements extending from the actuator element 30 . However, in some embodiment such as that shown in the figures, the axial dogs or projections 162 are shaped to match features of the clutch disk 26 with which they mate.

[0049] If employed, the protrusion 164 can surround any part or all of the aperture 154 . Also if employed, the projections 162 can be shaped and arranged to extend into the notches 142 formed in the clutch disk 26 such that rotational movement of the clutch disk 26 (e.g. in response to rotational movement of the lock cylinder 18 and driving engagement of the dogs 102 a , 102 b and the recesses 150 ) imparts rotational movement to the actuator element 30 due to driving engagement between the projections 162 and the clutch protrusions 138 . For reasons that will become apparent below, at least one of the notches 142 in the clutch disk 26 is not engaged or otherwise occupied by the projections 162 .

[0050] The lock mechanism 10 can be connected to a latch or other mechanism to be locked by a number of different elements and structure on the lock mechanism 10 . By way of example only, the lock mechanism 10 in the illustrated embodiment has a lock output tab 166 extending from the actuator element 30 . More specifically, the actuator element 30 in this embodiment includes a lock output tab 166 extending axially and radially away from the end wall 158 . The lock output tab 166 can be connected to, among other things, a latching device or an ignition switch for a vehicle such that rotational movement of the actuator element 30 moves the lock output tab 166 and locks/unlocks a connected device. As an alternative to a lock output tab 166 , the actuator element 30 can have an actuator shaft extending axially from the actuator element 30 , substantially aligned with the central axis 34 of the locking mechanism 10 and coupled to a vehicle ignition, door latch, or other mechanism for locking and unlocking the mechanism by rotation of the actuator shaft. In still other embodiments, the actuator element 30 can have one or more apertures, bosses, flanges, fingers, or other connecting points to which one or more cables, rods, levers, or other elements can be connected for transmitting motion from the locking mechanism 10 to a device connected thereto.

[0051] The above-described lock output tab 166 , axially extending shaft, and alternative connecting points of the actuator element 30 are only a small number of examples of lock output mechanisms. Many elements and mechanisms for transmitting rotational movement of the lock mechanism to rotational, translational, and other types of movement for actuation of various devices (e.g. door latches and vehicle ignitions) are well known to those skilled in the art. Each of these actuating elements and devices can be used in combination with the teachings of the present invention and fall within the spirit and scope of the present invention. The use of the locking mechanism 10 in a vehicle and/or for locking and unlocking a door latch is merely exemplary. Many other uses and applications for the locking mechanism 10 according to the present invention would be contemplated by those of skill in the art.

[0052] As mentioned above, the end of the boss 98 extending away from the barrel portion 78 of the lock cylinder 18 has a circumferential groove 100 for receiving a clip 170 . In this regard, when the locking mechanism illustrated in the figures is assembled (see FIGS. 4 and 5 ), a portion of the lock cylinder boss 98 extends beyond the end wall 158 of the actuator element 30 such that the circumferential groove 100 in the end of the boss 98 is exposed. The retaining element 170 (e.g., a C or E-clip, a retaining ring, and the like) is positioned in the circumferential groove 100 to secure the components of the locking mechanism 10 within the housing 14 . In other embodiments of the present invention, the boss 98 (or at least the end thereof) can be threaded so that a nut or other conventional fastener can used in place of or in addition to the retaining element 170 . In still other embodiments, the actuator element 30 is retained in place with respect to the housing 14 and the other elements of the locking mechanism 10 by one or more inter-engaging lips and grooves (e.g., a circumferential groove in the housing 14 within which a flange, lip, rib, or other circumferential protrusion of the actuator element 30 extends, and the like). Still other manners of connection between the actuator element 30 and the lock cylinder 18 are possible, each permitting relative rotation between the actuator element 30 and the housing 14 and each falling within the spirit and scope of the present invention.

[0053] In some embodiments of the present invention such as that shown in the figures, it is desirable to bias the clutch disk 26 toward the sleeve 22 . A number of different spring elements in a number of different locations can be employed for this purpose. In the illustrated embodiment for example, the locking mechanism 10 includes a biasing element in the form of a helical compression spring 174 located between the clutch disk 26 and the actuator element 30 . In other embodiments, other types of spring elements can be employed, such as leaf springs, resilient bushings, Belleville washers, and the like. The spring 174 in the illustrated embodiment surrounds and receives the annular protrusions 146 , 164 , although such protrusions are not required to bias the clutch disk 26 as described above. The spring 174 is compressed between the clutch disk 26 and the actuator element 30 such that a biasing force is applied to the clutch disk 26 , thereby biasing the clutch disk recesses 150 into engagement with the lock cylinder dogs 102 a , 102 b . In addition to biasing the clutch disk 26 into engagement with the lock cylinder 18 , the spring 174 can also provide a biasing force between the lock cylinder 18 and the actuator element 30 , thereby reducing the amount of rattling that occurs between various lock components of the locking mechanism 10 .

[0054] In addition to the compression spring 174 , another biasing element can also be provided to bias the lock cylinder 18 and/or the actuator element 30 toward a predetermined angular orientation with respect to the housing 14 . For example, a torsion spring 178 can be connected to the housing 14 and to the actuator element 30 or clutch disk 26 to bias the actuator element 30 , clutch disk 26 , and lock cylinder 18 toward an unactuated position. In the illustrated embodiment, the torsion spring 178 engages the reaction tab 68 on the housing 14 and at least one of the projections 162 of the actuator element 30 in such a way that rotation of the actuator element 30 with respect to the housing 14 creates an angular biasing force in the torsional spring 178 . The biasing force acts against rotation of the actuator element 30 and urges the actuator element 30 back toward its original angular position. One having ordinary skill in the art will appreciate that other types of springs and spring elements can be employed to urge the actuator element 30 and/or lock cylinder 18 to an unactuated position with respect to the housing 14 , and that such springs and spring elements can be connected to provide this biasing force in a number of different manners, each one of which falls within the spirit and scope of the present invention. For example, some embodiments of the invention can include a single spring that functions as the compression spring 174 and the torsion spring 178 .

[0055] In some embodiments, it is desirable to limit movement of the actuator element 30 in the unlocked state of the locking mechanism 10 and/or to limit movement of the clutch disk 26 in the locked state after the dogs 102 a , 102 b of the lock cylinder 18 are disengaged from the clutch disk 26 . In the embodiment shown in FIGS. 1-9 , the pin 64 of the locking mechanism 10 provides this limit. The through hole 62 (see FIGS. 4 and 5 ) in the housing, and therefore the pin 64 , is positioned such that when the lock cylinder 18 has not been rotated, the pin 64 is substantially angularly aligned with one of the notches 142 in the clutch disk 26 (see FIG. 6 ). Specifically, the pin 64 is radially aligned with the notch 142 that is not engaged or occupied by the axial projections 162 of the actuator element 30 . In addition, the pin 64 is axially offset from the clutch disk 26 toward the retaining end 54 of the housing 14 .

[0056] If the lock cylinder 18 is rotated with the proper key inserted, the actuator element 30 will rotate until one of the actuator element projections 162 engages the pin 64 , thereby preventing further rotation of the actuator element 30 and lock cylinder 18 (see FIG. 9 ). The pin 64 and projection 162 are configured to allow sufficient rotation of the actuator element 30 (e.g. through the angle Omega) such that the device to which the actuator element 30 is coupled (e.g. a door latch, a vehicle ignition switch, and the like) can be effectively actuated. As will be described in greater detail below, if the lock cylinder 18 is rotated without the proper key inserted, the clutch disk 26 is axially moved until the pin 64 is received within a notch 142 of the clutch disk to prevent frictional engagement of the sleeve 22 and clutch disk 26 from turning the clutch disk 26 (or at least to limit the rotation of the clutch disk 26 ).

[0057] Given the arrangement and configuration of the various components described above, the locking mechanism 10 provides free rotation of the lock cylinder 18 within the housing 14 when an attempt to rotate the lock cylinder 18 is made using substantially any item other than the appropriate key (e.g. the wrong key, a screwdriver, or the like). As used herein, “free rotation” of the lock cylinder 18 is means that rotation of the lock cylinder 18 does not impart significant rotational movement to the actuator element 30 or otherwise imparts insufficient rotational movement to the actuator element 30 to fully actuate the device connected to the locking mechanism 10 . By restricting the amount of rotational movement transmitted from the lock cylinder 18 to the actuator element 30 to a relatively small angle (e.g. the angle alpha of FIG. 7 , which is significantly smaller than the angle Omega of FIG. 9 ), operation of the device or mechanism to which the actuator element 30 is coupled is precluded. Of course, if the appropriate key is inserted into the lock cylinder 18 , rotation of the lock cylinder 18 results in less restricted rotation (and in some embodiments, unrestricted rotation) of the actuator element until such time as the actuator element projection 162 engages the pin 64 . Accordingly, by using the appropriate key, the locking mechanism 10 is fully operational to lock/unlock or activate/deactivate the associated device or mechanism to which the actuator element 30 is coupled.

[0058] With continued reference to the embodiment of the present invention illustrated in FIGS. 1-8 , when substantially any item other than the appropriate key is used to rotate the lock cylinder 18 , the lock cylinder 18 remains in the locked condition such that the sidebar 94 remains extended and projects into the groove 130 in the sleeve 22 (see FIGS. 4 and 5 ). As such, the lock cylinder 18 and the sleeve 22 are substantially rotatably fixed to each other. In alternative embodiments, the tumblers 82 may also or alternatively extend from the lock cylinder 18 and project into the slots 118 to rotatably fix the lock cylinder 18 to the sleeve 22 . In response to coupled rotation of the lock cylinder 18 and the sleeve 22 together, the cam projections 50 in the housing 14 and the cam recesses 126 in the sleeve 22 engage each other and urge the sleeve 22 axially toward the retaining end 54 of the housing 14 .

[0059] As the sleeve 22 moves axially along the housing 14 , the clutch-engaging surface 128 of the sleeve 22 engages the clutch disk 26 such that the clutch disk 26 is urged against the biasing force of the compression spring 174 axially toward the retaining end 54 of the housing 14 . As the clutch disk 26 moves axially in this manner, the clutch recesses 150 become disengaged from the dogs 102 a , 102 b . At this time, the lock cylinder 18 and the clutch disk 26 are no longer drivingly coupled for rotation together. In addition, movement of the sleeve 22 as described above brings the sleeve groove 130 over the radially extending drive dog 102 a , thereby bringing the sleeve groove 130 and drive dog 102 a into driving relationship. Substantially simultaneously, and also due to axial movement of the clutch disk 26 , the clutch disk notch 142 that is not occupied by one of the actuating element projections 162 receives the pin 64 .

[0060] The angle of rotation of the clutch disk 26 (and therefore, of the actuator element 30 in its locked state) can vary widely depending at least in part upon the size of the notch 142 and the radial clutch protrusions 138 . Similarly, the angle of rotation of the actuator element 30 in its unlocked state can vary widely depending at least in part upon the distance between the pin 64 and the axial projection 162 that limits movement of the actuator element 30 . In some embodiments, the angle of rotation of the clutch disk 26 in the locked state of the locking mechanism 10 is less than about 30 degrees. In other embodiments, this angle is about 15 degrees or less.

[0061] Once the clutch protrusion 138 engages the pin 64 in the locked state of the locking mechanism 10 , further rotation of the clutch disk 26 is prevented. During axial movement of the clutch disk 26 in some embodiments, the clutch notches 142 and the axial projections 162 of the actuator element 30 slide axially with respect to each other such that there is substantially no axial movement of the actuator element 30 with respect to the housing 14 . The locking mechanism 10 and the device to which the mechanism 10 is attached are configured such that the small amount of actuator element rotation that occurs as the clutch disk 26 is disengaged from the lock cylinder 18 does not fully operate, actuate, or otherwise influence the state (e.g., locked or unlocked) of the device.

[0062] With continued reference to the embodiment illustrated in FIGS. 1-9 , as the lock cylinder 18 and the sleeve 22 continue to rotate together, the cam recesses 126 disengage the cam projections 50 , and the clutch recesses 150 disengage the dogs 102 a , 102 b (see FIG. 5 ). Also, the clutch disk 26 and the actuator element 30 remain substantially stationary (both axially and rotationally) with respect to the housing 14 due to engagement between the clutch disk 26 and the pin 64 while the clutch-engaging surface 128 slidingly engages the clutch disk 26 . In the illustrated embodiment having two cam recesses 126 and two cam projections 50 , once the lock cylinder 18 and the sleeve 22 have been rotated approximately 180 degrees, the cam recesses 126 and cam projections 50 are once again aligned (albeit with an opposite cam recess 126 and cam projection 50 ) and the biasing force of the compression spring 174 urges the clutch disk 26 and the sleeve 22 axially toward the cylinder-receiving end 38 of the housing 14 , thereby re-engaging the cam recesses 126 with the cam projections 50 , and the clutch recesses 150 with the lock cylinder dogs 102 a , 102 b . Still further rotation of the lock cylinder 18 in a forceful manner repeats the disengagement/re-engagement cycle. Accordingly, the lock cylinder 18 can by continuously rotated by an improper key or other object without imparting significant rotational force to the actuator element 30 , tumblers 82 , or sidebar 94 , thereby preventing alteration of or damage to the locking mechanism 10 and preventing the device connected thereto from becoming unlocked. Regardless of whether the lock cylinder 18 is rotated in the locked or unlocked condition, the lock cylinder 18 remains substantially axially fixed with respect to the housing.

[0063] In other embodiments of the present invention in which fewer or more apertures or recesses 118 , 130 are provided in the sleeve 22 , the lock cylinder 18 can be rotated different amounts before being re-engaged with the housing 14 in a manner similar to that described above. For example, in embodiments having a single set of tumblers 82 and a single elongated aperture 118 in the sleeve 22 , the lock cylinder 18 can be rotated approximately 360 degrees to become re-engaged with the sleeve 22 .

[0064] In some embodiments, if the lock cylinder 18 is forcibly rotated when in the locked condition through a sufficient angle to result in axial translation of the sleeve 22 , but not so far as to allow the lock cylinder dogs 102 a , 102 b to re-engage with the clutch recesses 150 , engagement between the radially extending cylinder dog 102 a and the sidebar groove 130 of the sleeve 26 facilitates returning the lock to an operative mode using the appropriate key. Specifically, when the appropriate key is inserted into a partially rotated lock cylinder 18 , the sidebar 94 and/or the tumblers 82 (depending upon the configuration of the lock cylinder 18 ) are retracted from the groove 130 and/or the elongated apertures 118 , respectively, so that the sidebar 94 and/or the tumblers 82 no longer couple the sleeve 22 and the lock cylinder 18 for rotation together. With this in mind, the radially extending dog 102 a and the groove 130 are configured to couple the lock cylinder 18 and the sleeve 22 for rotation together when the sidebar 94 and/or the tumblers 82 are retracted. Thus, the lock cylinder 18 can be restored to a normal operating condition by rotating the lock cylinder 18 with the appropriate key fully inserted until such time as the cam projections 50 and the cam recesses 126 are again aligned, the sleeve 22 snaps axially toward the receiving end 38 of the housing 14 (under influence of the spring 174 ), and the clutch disk 26 snaps axially toward the receiving end 38 of the housing as the dogs 102 a , 102 b are one again received within the clutch recesses 150 .

[0065] During normal operation of the embodiment illustrated in FIGS. 1-9 , when the appropriate key is inserted into the lock cylinder 18 , the sidebar 94 (and/or the tumblers 82 if so configured) retracts into the barrel portion 78 of the lock cylinder 18 such that the lock cylinder 18 and the sleeve 22 are no longer coupled for rotation together. It will be appreciated that for locks that do not include a sidebar (e.g. “tumbler locks”), the tumblers fully retract within the barrel portion 78 of the lock cylinder 18 to decouple the lock cylinder 18 from the sleeve 22 .

[0066] When the lock cylinder 18 is subsequently rotated, the sleeve 22 remains substantially stationary with respect to the housing 14 . As such, there is substantially no axial movement of the sleeve 22 or the clutch disk 26 , and the clutch recesses 150 remain engaged with the lock cylinder dogs 102 a , 102 b . In addition, because the radial clutch disk protrusions 138 do not engage the pin 64 , the clutch disk 26 is free to rotate with respect to the housing 14 . Thus, as the lock cylinder 18 is rotated, the clutch disk 26 and the actuator element 30 are also rotated due to the engagement between the dogs 102 a , 102 b and the recesses 150 as well as the engagement between the clutch disk notches 142 and the actuator element projections 162 . Rotation of the actuator element 30 through a sufficient angle results in operation of the device to which the actuator element is coupled (e.g., actuation of the device to a locked or unlocked state). Once the lock cylinder 18 has been sufficiently rotated, the torsional spring 178 (if employed) returns the lock cylinder 18 to its original angular orientation with respect to the housing 14 . Regardless of whether the lock cylinder 18 is rotated with the appropriate key inserted or not, the lock cylinder 18 can remain substantially axially fixed with respect to the housing 14 .

[0067] In addition to preventing forceful turning of the lock cylinder 18 by inserting an object into the key slot 90 , the locking mechanism 10 also prevents substantial rotation of the actuator element 30 by grasping, pulling, or otherwise directly manipulating the actuator element 30 . For example, if the locking mechanism 10 is installed in a vehicle door, attempts to overcome the lock may be made by inserting a thin piece of metal including a small hook (often referred to as a “slim-jim”) between the outer door housing and the door glass. The hook is then engaged with the lock output tab 166 in an effort to move the lock output tab 166 sufficiently to unlock the vehicle door. If such an attempt to overcome the locking mechanism 10 is made, the lock output tab 166 will only be movable through the relatively small angle alpha such that unlocking of the door is substantially prevented. Specifically, as the actuator element 30 is rotated, the driving engagement between the projections 162 and the clutch protrusions 138 causes the clutch disk 26 to rotate with respect to the housing 14 . Also, the driving engagement between the clutch recesses 150 and the dogs 102 a , 102 b impart rotation to the lock cylinder 18 which in turn imparts rotation to the sleeve 22 due to the engagement between the sidebar 94 (which remains extended) and the groove 130 . As discussed above, rotation of the sleeve 22 with respect to the housing 14 causes the sleeve 22 and the clutch disk 26 to move axially toward the retaining end 54 . Such axial movement of the clutch disk 26 causes one of the radial clutch disk protrusions 138 to engage the pin 64 , thereby preventing further rotation of the clutch disk 26 . Because the clutch disk 26 and the actuator element 30 are substantially always coupled for rotation together, preventing further rotation of the clutch disk 26 prevents further rotation of the actuator element 30 . As such, once the actuator element 30 is rotated through the relatively small angle alpha, further rotation of the actuator element 30 (which would result in unlocking of the door) is substantially prevented.

[0068] FIGS. 10-18 illustrate a locking mechanism 210 according to another embodiment of the present invention. The locking mechanism 210 illustrated in FIGS. 10-18 and described below shares much in common with the locking mechanism 10 described above and illustrated in FIGS. 1-9 . Accordingly, the description above regarding the various elements and features of the first illustrated embodiment (as well as the alternatives of such elements and features also described above) applies to corresponding elements and features in the second illustrated embodiment of FIGS. 10-18 , with the exception of mutually inconsistent elements and features between these embodiments.

[0069] With reference first to FIGS. 10-13 , the locking mechanism 210 includes an outer housing 214 , a lock cylinder 218 received within the housing 214 , a sleeve 222 also received with the housing 214 and surrounding at least a portion of the lock cylinder 218 , and a pair of sleeve guides 224 positioned between the lock cylinder 218 and the sleeve 222 . The locking mechanism 210 also includes an actuator element 230 that is adapted for connection to a cable for actuation thereof, and an endcap 231 that cooperates with the housing 214 to substantially encase the remaining lock components. It will be appreciated, however, that other types of actuator elements for actuating different types of mechanisms can be used as well.

[0070] The housing 214 provides a generally cylindrical, open-ended cavity 232 and defines a central axis 234 . In this regard, the housing 214 can take any shape within which the lock cylinder 218 can be received, and in some embodiments (such as that shown in the figures) has a generally round cross-sectional shape. The housing 214 can enclose any amount of the lock cylinder 218 desired, such as by surrounding the length of the lock cylinder as shown in the figures.

[0071] The housing 214 can include outwardly extending mounting protrusions 236 that are securable to, among other things, a vehicle door or vehicle steering column that is to be lockably secured by the locking mechanism 210 . The mounting protrusions 236 can take a variety of different forms and are generally determined by the device or mechanism (e.g. a vehicle part or assembly) to which the locking mechanism 210 is to be secured.

[0072] A cylinder-receiving end 238 of the housing 214 includes an internal lip 242 for limiting axial movement of the lock cylinder 218 and the sleeve guides 224 within the housing 214 . In other embodiments, lock cylinder and sleeve guide travel can be limited in any other manner desired, and by different structural features. For example, one or more bosses, pins, neck portions, and other features of the housing 214 (as well as element attached to the housing 214 ), can limit the travel of one or both of the lock cylinder and the sleeve guides, each of which falls within the spirit and scope of the present invention.

[0073] For purposes that will be described in greater detail below, the housing 214 also includes a cam surface 246 extending radially into the cavity 232 and facing axially away from the receiving end 238 . The cam surface 246 defines one or more axial cam recesses 250 within the cavity 232 .

[0074] Opposite the cylinder-receiving end 238 of the housing 214 is a retaining end 254 . The retaining end 254 of the housing 214 can be the same size as the cylinder-receiving 238 end or can have any other size desired, and in some embodiments (such as that illustrated in the figures) is somewhat diametrically enlarged with respect to the receiving end 238 of the housing 214 . The retaining end 254 includes a radially outwardly extending circumferential lip 256 that is engageable with the endcap 231 , and a radially outwardly positioned and axially extending return spring arm 258 .

[0075] The lock cylinder 218 is received within the cavity 232 and can take any conventional lock cylinder form. By way of example, the lock cylinder 218 in the illustrated embodiment includes a barrel portion 278 that houses a plurality of lock tumblers 282 . Other types of tumbler or pin-type lock cylinders can be employed in conjunction with the present invention as desired. Although the lock cylinder 218 can have any shape, the lock cylinder 218 illustrated in the figures includes an end flange 286 that seats against the internal lip 242 in the housing 214 when the lock cylinder 218 is inserted into the cavity 232 . The internal lip 242 assists in properly positioning the lock cylinder 218 with respect to the housing 214 , and can be replaced with any number of other elements and structure capable of performing the same function (including those described above with reference to the internal lip 42 ).

[0076] At one end of the lock cylinder 218 is a key slot 290 that receives a key (not shown). When an appropriate key is inserted into the lock cylinder 218 , the lock tumblers 282 engage the key and move within the barrel portion 278 to predetermined positions such that the lock cylinder 218 is placed in an unlocked state. If no key or an incorrect key is inserted into the lock cylinder 218 , one or more of the lock tumblers 282 will be improperly positioned, and the lock cylinder 218 will remain in a locked state.

[0077] In some embodiments of the present invention, when the lock cylinder 218 is in the locked state, one or more of the tumblers 282 extend radially outwardly from the barrel portion 278 to engage the sleeve guides 224 , the housing 214 , or another adjacent element or elements, and to thereby prevent rotation of the lock cylinder 218 . When an appropriate key is inserted into the lock cylinder 218 , the tumblers retract radially inwardly into the barrel portion 278 to a position corresponding to the unlocked state of the lock cylinder 218 . In alternate embodiments of the present invention (such as those described above with respect to FIGS. 1-9 ), the lock cylinder 218 can also include a sidebar that functions and operates substantially the same as the sidebar 94 described above. The specific operation of and interaction between the key and the lock tumblers 282 (as well as between the lock tumblers 282 and the sidebar, where employed) are well known in the art and are therefore not discussed further herein. While one specific type of lock cylinder 218 is illustrated in the drawings, substantially any type of rotatable lock cylinder is suitable for use with the present invention.

[0078] The lock cylinder 218 in the illustrated embodiment also has an axially extending boss 298 (substantially aligned with the central axis 234 when the lock cylinder 218 is received within the cavity 232 ) that helps to maintain the position of the lock cylinder 218 in the locking mechanism 210 . The boss 298 can have any shape desired, such as the generally cylindrical shape shown in the figures. With continued reference to the illustrated embodiment, one or more dogs 302 extend radially outwardly from the boss 298 . The dogs 302 can have any shape desired suitable for establishing driving engagement with the actuator element 230 as will be described in greater detail below. In this regard, the lock cylinder 218 can have a single dog 302 or more than two dogs 302 for this purpose. The dogs 302 can be located in any position on the lock cylinder 218 facilitating releasable engagement with the actuator element 230 , and in the illustrated embodiment extend in diametrically opposite positions from the axially extending boss 298 .

[0079] In some embodiments of the present invention, the axially extending boss 298 includes a groove 300 extending fully or partially around its distal end for receiving a clip 370 or other fastener that retains the elements of the locking mechanism 210 in their proper relative positions. In other embodiments, the elements of the locking mechanism 210 can be retained in their proper relative positions in other ways, such as by tightening a nut on a threaded end of the axially extending boss 298 , by any conventional fastener secured to the end of the axially extending boss 298 , and the like.

[0080] The sleeve guides 224 in the illustrated embodiment of FIGS. 10-18 are substantially identical. Accordingly, only one of the illustrated sleeve guides 224 will be described below. However, it should be noted that a single sleeve guide 224 , or three or more sleeve guides 224 can instead be used. Furthermore, when a plurality of sleeve guides 224 are used, the sleeve guides 224 need not necessarily be identical to one another. Each sleeve guide 224 is contoured to lie adjacent a portion of the barrel portion 278 . With reference to FIGS. 14 and 15 , each illustrated sleeve guide 224 has an arcuate cross-sectional shape and includes an inner surface 304 that faces the barrel portion 278 between the diametrically opposed lock tumblers 282 . Each sleeve guide also has an outer surface 306 having a radial projection 307 extending radially away therefrom. In the illustrated embodiment, the radial projection 307 is generally rectangular. However, the radial projection 307 can have any other shape desired. Furthermore, more than one projection can be provided on each sleeve guide 224 , if desired.

[0081] Each sleeve guide 224 in the exemplary illustrated embodiment also includes two radially and axially extending bearing surfaces 308 extending between the inner and outer surfaces 304 , 306 . In the illustrated exemplary embodiment, the two sleeve guides 224 are positioned diametrically opposite one another and closely surround the barrel portion 278 . When the lock cylinder 218 is in the locked state, the tumblers 282 extend radially from the barrel portion 278 and between the bearing surfaces 308 of the two sleeve guides 224 . If the lock cylinder 218 is rotated with respect to the housing 210 while in the locked configuration, at least one of the tumblers 282 contacts at least one of the bearing surfaces 308 such that the sleeve guides 224 are substantially rotatably fixed with respect to the lock cylinder 218 , or otherwise limit the amount of rotation of the lock cylinder 218 with respect to the sleeve guides 224 .

[0082] In some embodiments, the pressure that may be applied to the bearing surfaces 308 by forced rotation of the lock cylinder 218 in the locked state (e.g., when forced by a thief or other unauthorized person) can be sufficient to cause one or more of the tumblers 282 to “bite into” either or both sleeve guides 224 . In this regard, the sleeve guides 224 can therefore be at least partially axially fixed with respect to the tumblers 282 when the lock cylinder 218 is forced to rotate in the locked state.

[0083] In those embodiments of the preset invention employing a sidebar as described above, the sleeve guides 224 can also include or can cooperate to define an aperture or recess configured to receive the sidebar. The aperture or recess for the sidebar can have any shape and location suitable for receiving the sidebar. In some embodiments, the aperture or recess is an axially extending groove that is recessed within or with respect to the inner surface 304 of the sleeve guide 224 for receiving the sidebar when the sidebar is extended (axially away from the lock cylinder 218 ). In some embodiments of the present invention, the engagement between the sidebar and the aperture or recess alleviates the need for engagement between the tumblers 282 and the bearing surfaces 309 . In this respect, some embodiments of the present invention can include tumblers 282 that do not extend from the lock cylinder 218 regardless of the condition (e.g. locked or unlocked) of the lock cylinder 218 .

[0084] Referring now to FIGS. 16 and 17 , the sleeve 222 in the illustrated exemplary embodiment is generally tubular and is received within the annular space formed between the housing 214 and the sleeve guides 224 when the lock cylinder 218 and sleeve guides 224 are inserted into the cavity 232 . An outer surface 310 of the sleeve 222 faces the housing 214 , and an inner surface 314 of the sleeve 222 faces the outer surfaces 306 of the sleeve guides 224 . In some embodiments (such as the illustrated exemplary embodiment of FIGS. 10-18 ), the sleeve 222 has at least one aperture or recess 318 within which the radial projections 307 of the sleeve guides 224 can be received, or has at least one bearing surface against which the radial projections 307 of either or both sleeve guides 224 can push when the sleeve guides 224 are rotated about the axis of the lock cylinder 218 (as will be described in greater detail below) in either or both directions.

[0085] By way of example only, in those embodiments of the present invention having one sleeve guide 324 , the sleeve 222 can have a single aperture or recess 318 . As another example, the sleeve 222