EP1073815A1

EP1073815A1 - Key operated latch with combined rotational and translational latching action

Info

Publication number: EP1073815A1
Application number: EP00907304A
Authority: EP
Inventors: Michael Anthony Rumsey; Thomas D. Goham; Corey Perkins
Original assignee: Southco Inc
Current assignee: Southco Inc
Priority date: 1999-02-18
Filing date: 2000-02-18
Publication date: 2001-02-07
Anticipated expiration: 2020-02-18
Also published as: EP1073815B1; CA2329425A1; JP2002537506A; DE60040579D1; WO2000049251A1; BR0004887A; AU2882600A; EP1073815A4; KR20010042812A; KR100656096B1

Abstract

A key operated latch (10) includes a housing which supports a lock plug (111), a motion control sleeve (40), and a sleeve-like cam (20) therein. The cam (20) rotates with the lock plug (111), while the motion control sleeve (40) is stationary. The cam (20) has at least one cam slot, and the motion control sleeve (40) has at least one motion control slot. A shaft (50) extends outward from the housing and has at least one projection which is engaged with both the cam slot and the motion control slot. The cam slot and the motion control slot are configured such that rotation of the lock plug imparts a sequence of rotational and axial movements to the shaft (50). A latching member (70) attached to the shaft, moves between a latched position and an unlatched position in a sequence of axial and rotational motions in order to selectively secure a door, panel, or the like in the closed position.

Description

KEY OPERATED LATCH WITH COMBINED ROTATIONAL AND TRANSLATIONAL LATCHING ACTION

TECHNICAL FIELD

The present invention relates generally to latching devices and more particularly to latching devices for securing a first member such as a door, panel or the like in a closed position relative to a second member such as a corresponding door, panel or frame.

BACKGROUND ART

Various types of latching devices for use in securing a first closure member such as a door, panel or the like in a closed position relative to a corresponding second closure member such as a door, panel or frame are known. Some types incorporate a pawl or similar latching member that is actuated to engage a closure member for latching. In particular, latches have been proposed which operate to move the latching member both rotationally and translationally to engage a closure member for latching. For example, U.S. Patent Number 5,165,738, issued to Edward McCormack on November 24, 1992, U.S. Patent Number 4,878,367, issued to Robert H. Bisbing on November 7, 1989, U.S. Patent Number 4,583,775, issued to Robert H. Bisbing on April 22, 1986, and U.S. Patent Number 4,556,244, issued to Robert H. Bisbing on December 3, 1985, all show latching mechanisms with a combined rotational and translational latching action. However, none of the references cited previously teach or suggest the unique structural features of the key operated latch of the present invention.

DISCLOSURE OF INVENTION

The present invention is generally directed to a key operated latch for use with a door, panel or the like. The latch includes a housing having a bore, a first end, and a second end. A lock plug, a lock plug sleeve, a motion control sleeve, and a sleeve-like cam are received within the bore of the housing. The lock plug sleeve and the motion control sleeve are supported within the housing such that they are stationary relative to the housing. The lock plug is positioned coaxially with the lock plug sleeve and is selectively rotationally movable relative to the lock plug sleeve by using a key. The sleeve-like cam is coupled to the lock plug such that it rotates with the lock plug. The sleeve-like cam has at least one cam slot, and the motion control sleeve has at least one motion control slot. The latch further includes a shaft which is positioned at least in part within the housing, with a portion of the shaft extending outward from the second end of the housing. The shaft has at least one projection which is engaged with both the cam slot and the motion control slot. The cam slot and the motion control slot are configured such that rotation of the lock plug imparts movement to the shaft which is a sequence of movements including a rotational movement and an axial movement. A latching member is supported by the shaft outside the housing such that the latching member and the shaft move as a unit. Thus, the latching member moves between a latched position and an unlatched position in a sequence of axial and rotational motions in order to selectively, releasably secure the door, panel, or the like in the closed position.

Accordingly, it is an object of the present invention is to provide a novel key operated latch.

Another object of the present invention is to provide a novel latch of the type incorporating a pawl or similar member and which is actuated through operation of a key. Yet another object of the present invention is to provide a novel key operated latch where the pawl moves both rotationally and axially.

Still another object of the present invention is to provide a novel latch which applies a compressive force between first and second closure members.

These and other objects of the present invention will become more readily apparent when taken into consideration with the following description and the attached drawings.

BRIEF DESCRIPTION OF DRAWINGS

Figs. 1 -7 are views of a latch assembly in accordance with an embodiment of the present invention. Fig. 8 is an exploded view of the latch assembly of figs. 1-7.

Figs. 9-16 are views of a bushing, slightly enlarged, of the latch assembly of fig. 8.

Figs. 17-24 are views of a lock plug sleeve, slightly enlarged, of the latch assembly of fig. 8. Figs. 25-31 are views of a motion control sleeve, slightly enlarged, of the latch assembly of fig. 8.

Figs. 32 and 33 are views of a housing, slightly enlarged, of the latch assembly of fig- 8.

Fig. 34 is a side elevational view of a cam, slightly enlarged, of the latch assembly of fig. 8.

Fig. 35 is a top plan view of a retainer, slightly enlarged, of the latch assembly of fig. 8.

Fig. 36 is a cross sectional view of the latch assembly of figs. 1-7 taken along the line 36-36 of fig. 2. Figs. 37-39 are side elevational views of the latch assembly of figs. 1-7, slightly enlarged, with the housing and sleeve portions in section and the latch assembly being shown in a closed or latched position in fig. 37, in an open or unlatched position in fig. 39 and in a transitional position between the closed and open positions in fig. 38.

BEST MODE FOR CARRYING OUT THE INVENTION

The present invention is directed to a key operated latch that has broad application and may be used with a wide variety of closure members, such as a door or the like, for releasably securing a closure member in the closed position.

Illustrated in the figures is one embodiment of a latch in accordance with the present invention. The particular latch illustrated in the present embodiment is similar in many aspects to a latch shown, described and claimed in U.S. Patent No. 4,583,775('755 Patent) entitled "Latch Assembly Having Pull-Up Action", which is incorporated by reference herein. For the sake of brevity, emphasis will be made in the following description to the features in the present embodiment which differ from that set forth in the '775 Patent.

As illustrated in the figures, the latch assembly 10 in accordance with the present embodiment includes, as portions thereof, a housing 30, a shaft 50 having an end 54, fastening means comprising in this embodiment a latching pawl 70 mounted on the threaded end of the shaft 50 as by mounting nuts 71, and actuating means comprising in this embodiment a sleeve-like cam 20, a motion control sleeve 40, a cross-pin 60, a lock plug 111, a lock plug sleeve 113, a bushing 115, a retaining ring 117 and a key 119, the details of which will be described below. In the present embodiment, the latching pawl 70 is movable rotationally by shaft

50 and is also moveable by shaft 50 axially in the longitudinal direction of the shaft. In operation, the latch assembly 10 is mounted in an opening through one member, such as a closure member, and the pawl is moved to engage a second member, such as a corresponding frame. To latch the closure member to the frame, the latching pawl 70 is first rotated to a position such that it is in line with the frame member. The latch pawl 70 is then moved longitudinally so that it engages the edge of the frame. The shaft 50 is moved rotationally and also longitudinally by means of the actuating means.

The lock plug 111 is generally cylindrical and in the nature of a conventional lock plug including a key access opening and an array of wafers that retract upon insertion of the key 119. The lock plug sleeve 113 is also generally cylindrical and includes a bore 18 generally cylindrical in configuration and which receives the lock plug 111. The bushing 115 comprises a generally annular member in this embodiment including an opening 130 therethrough and operates to retain the internal components, including the lock plug 111, lock plug sleeve 113, sleeve-like cam 20, motion control sleeve 40 and cross-pin 60. The retaining ring 117 is also a generally annular member and operates to hold the foregoing components of the actuating means within the housing 30.

The housing 30 in the present embodiment is a generally elongate component having a first end, a second end, a bore extending longitudinally through the housing 30 and an outer surface. The second end 32 of housing 30 has a central opening, contiguous with the bore of the housing 30, through which the shaft 50 passes. As used herein, the distal end of a component part refers to that end of the component part which is located farthest from the first end of the housing 30, when the latch 10 is fully assembled, while the proximal end of a component part is the end closest to the first end of the housing 30, again when the latch 10 is fully assembled. In the present embodiment, the distal ends of the motion-control sleeve 40 and sleeve-cam 20 abut against the end wall surrounding the central opening in the second end 32 of the housing 30. The lock plug 111 and lock plug sleeve 113 are positioned within the bore of the housing 30 adjacent to the first end 33 of the housing 30. The outer surface of the housing 30 includes a flanged first portion 35 adjacent to the first end 33. The outer surface of the housing 30 also includes a second portion 37. The second portion 37 of housing 30 is provided with interrupted screw threads along a portion of the outer surface thereof. The screw threads on the outer surface of the second portion 37 of the housing 30 are interrupted by four flats formed on the outer surface of the housing 30. The flats formed on the outer surface of the housing 30 prevent the rotation of the housing 30 when the key 119 is used to turn the lock plug 111, once the latch 10 is installed in a closure member such as a door or the door's frame. The interrupted threads on the outer surface of the housing 30 are engaged by a nut to secure the latch 10 in place, once the latch 10 is installed in a closure member such as a door or the door's frame.

In the present embodiment, the lock plug 11 1 is rotatable within the housing 30 and is prevented from movement in the axial direction, i.e. along the longitudinal axis of the housing 30, by the retaining ring 117. The retaining ring 117 is received within grooves 13 and 161, which are located in the bushing 115 and the housing 30, respectively, and are in registry with one another. As a result, the bushing 1 15 and retaining ring 117 rotate on rotation of lock plug 111. In addition, means are provided between the lock plug 111 and cam 20 for providing for the rotation of the cam 20 on rotation of the lock plug 111. In the illustrated embodiment, the distal end of the lock plug

111 is provided with a pair of notches 16 which receive ears 21 projecting axially from the proximal end of the cam 20. Thus, when lock plug 111 is rotated, as by the key 119, the sleeve-like cam 20 is also rotated. The sleeve-like cam 20 is provided with at least one and, in the present embodiment, a pair of cam slots 25 spaced 180° apart circumferencially. Each of the slots 25 run in a direction which has both circumferencial and axial components. The lock plug sleeve 113 in this embodiment is received in housing 30 in a substantially fixed rotational position. As illustrated, the lock plug 111 is substantially surrounded by lock plug sleeve 113, which operates to substantially center the lock plug 113 within the opening in the housing 30. In addition, means are provided between lock plug sleeve 113 and lock plug 111 to provide locked and unlocked conditions of the latch assembly 10. In this embodiment, the lock plug sleeve 113 includes a groove 150 on its inner surface that cooperates with the wafers of lock plug 111 in order to provide the locked and unlocked conditions of the latch assembly 10. In particular, in this embodiment, the wafers of lock plug 111 are extended when key 119 is removed, and in this manner, rotation of lock plug 111 is prevented when the wafers are received in the groove 150 of sleeve 113. The wafers of lock plug 111 are retracted away from the groove 150 in lock plug sleeve 113 by insertion of key 119, which allows for subsequent rotation of lock plug 111 relative to lock plug sleeve 113.

Positioned coaxially between the hosing 30 and the sleeve-like cam 20 is a motion control sleeve 40 having a pair of motion control slots. Each motion control slot has an axial slot portion 41 and a circumferencial slot portion 42. Each of the axial portions 41 extends in a direction parallel to the longitudinal axis of the housing 30, and each of the circumferencial slot portions 42 extends along a length of arc of a circle formed in a plane perpendicular to the longitudinal axis of the housing 30, with the latch assembly 10 in the fully assembled configuration. In the present embodiment, the motion control slots are spaced 180° from one another. The end of each axial slot portion 41, located distally from the first end of the housing 30, connects with one end of a respective one of the circumferencial slots 42. The latch assembly 10 further includes means for substantially preventing rotation of the motion control sleeve 40 relative to housing 30. In this embodiment, the sleeve 40 includes two notches 152 at its lower end and which rest on two tabs 160 on the bottom interior of housing 30. The latch assembly 10 further includes means between the motion control sleeve 40 and lock plug sleeve 113 for substantially preventing rotation of lock plug sleeve 113 relative to housing 30. In this embodiment, the sleeve 40 includes a pair of notches 44 at its upper end and which receive ears 140 which project axially from the distal end of lock plug sleeve 113. The fixed motion control sleeve 40 may also be provided integral with the housing 30 being formed directly within or extending from an inner surface of the housing 30. The slot portions 41 and 42 in the motion-control sleeve 40 function respectively as rotational motion-control slots and as axial motion-control slots.

Shaft 50 is elongated and projects outward from the second end of the housing 30 by passing through the central hole at the second end 32 of housing 30. The shaft 50 is supported such that the longitudinal axis of the shaft 50 coincides with the longitudinal axes of the housing 30, the motion-control sleeve 40, and the cam 20. At least the majority of the portion of the shaft 50 which lies outside the housing 30, is provided with interrupted screw threads. The screw threads of the shaft 50 are interrupted by a pair of flats machined on either side of at least the threaded portion of the shaft 50. The threaded portion of the shaft 50 fits through a hole in one end of the pawl 70. The hole in the end of the pawl 70 has flat sides which match the flats on either side of the shaft 50. Thus, relative rotation between the pawl 70 and the shaft 50 is prevented, and the pawl 70 and the shaft 50 rotate about the longitudinal axis of the shaft 50 as a unit. The interrupted screw threads on the shaft 50 are engaged by the mounting nuts 71 in order to secure the pawl 70 in place at a desired location along the length of the threaded portion of the shaft 50.

The relative positions of the motion-control sleeve 40 and cam 20 could be reversed. That is, motion-control sleeve 40 could be inside of cam 20 rather than outside as shown. Mounted on the shaft 50 is the cross-pin 60 which projects laterally from opposite sides of the shaft 50 and functions as both a cam follower and as a motion- control pin. Cross-pin 60 cooperates with the cam 20 and the motion control sleeve 40 to control whether, in response to rotation of the lock plug 111, the shaft 50 and pawl 70 will move only axially or only rotationally. This is determined by whether the opposite ends of pin 60 are positioned through the axial slot portions 41 or through the circumferencial slot portions 42.

The housing 30 is mounted on the closure member by retaining means which, in the present embodiment, is comprised of a washer and a mounting nut engaging the threads on the outer surface of housing 30. In the present embodiment, the housing 30 is installed in a closure member by positioning the latch assembly 10 such that the housing

30 extends through an aperture passing through the closure member. The latch assembly 10 is installed such that the first end of the housing 30 is accessible by a user for insertion of the key 119. The installation of the latch assembly 10 is most easily accomplished when the pawl 70 is not mounted on the shaft 50, so that the shaft 50 can be inserted first through the aperture in the closure member. The pawl 70 can then be mounted to the shaft 50 after the housing 30 is positioned to extend through the aperture formed in the closure member, however, this sequence of steps for the installation of the latch assembly 10 is not a requirement. The housing 30 is then secured within the aperture of the closure member by the mounting nut and, if desired, also the washer.

In the present embodiment, the components of the latch assembly 10 are preferably comprised of metal and metal alloy materials, however, other suitable materials can also be used where desired. In addition, in the present embodiment, the closure member can be comprised of any suitable materials, such as wood or metal, and can be of varying thickness.

The operation of the latch when installed as part of an assembly including a closure member, will now be described. When lock plug 111 is rotated, as by the key 119, the sleeve-like cam 20 will be driven to rotate in the same direction as the lock plug 111. When cam 20 is rotated, cross pin 60 is moved, but whether the movement is axial or rotational is dependent upon whether the ends of pin 60 are in the axial slot portions or in the circumferencial slot portions of the motion-control sleeve 40. When in the latched position, lock plug 111 is at its fully clockwise position, and the two opposite ends of cross pin 60 are positioned through the axial slot portions 41 of the motion-control sleeve 40, near the ends of the axial slot portions 41 which are closest to the first end of the housing 30. In addition, the portions of the cross pin 60 projecting from either side of the shaft 50, simultaneously engage the cam slots 25 of the cam 20. At the extreme of the clockwise rotation of the lock plug 111, the projecting portions of the cross pin 60 are positioned nearest to the ends of the cam slots 25 which are closest to the proximal end of the cam 20. The pitch of each of the cam slots 25 is such that the axial distance, i.e. the distance measured in a direction parallel to the longitudinal axis of the cam 20, between a location along the cam slot 25 and the proximal end of the cam 20 increases in the clockwise direction, beginning at the end of the cam slot nearest the proximal end of the cam 20. To unlatch the closure member from, for example, the cabinet frame, lock plug 111 is turned in a counterclockwise direction. When this is done, lock plug 111 and cam 20 rotate as a unit. The cross pin 60 cannot move rotationally because its opposite ends are within the axial slot portions 41 of the stationary motion-control sleeve 40. As a result, when cam 20 is rotated counterclockwise, the opposite ends of pin 60 follow the opposed cam slots 25, and as a result, pin 60, and hence also shaft 50 and latch pawl 70, will move away from the first end of the housing 30 in a direction parallel to the longitudinal axis of the shaft 50. The axial movement of the shaft 50 and the pawl 70, away from the first end of the housing 30 and away from the frame of the closure member, continues until the ends of the pin 60 reach the circumferencial slot portions 42.

After lock plug 111 and cam 20 have been rotated as a unit through approximately 120 degrees, cross pin 60 has moved axially away from the proximal end of the motion control sleeve 40, and is now aligned with the opposed circumferencial slot portions 42. Further rotation of lock plug 1 11 and cam 20 now causes rotational movement of cross pin 60, shaft 50 and pawl 70, as the ends of pin 60 move along the opposed circuferencial slot portions 42. In this manner, pawl 70 is moved out of alignment with the frame member, and after approximately 60 degrees of rotation, the closure member or door is fully unlatched. Lock plug 1 11 has now been rotated approximately 180° relative to its fully latched position. The latching action is simply the reverse of the unlatching action just described.

On latching, as lock plug 1 11 is turned clockwise, the opposite ends of cross pin 60 move in the clockwise direction along the circumferencial slot portions 42 and the shaft 50 rotates in the clockwise direction about its longitudinal axis. Then the cross pin 60 translates axially toward the proximal end of the motion control sleeve 40, when the cross pin 60 reaches the axial slot portions 41. These sequential motions are caused by the walls

22 of the cam slots 25, which urge the ends of the cross pin 60 along the circumferential slot portions 42 in the clockwise direction, until the ends of the cross pin 60 abut against the edge of the axial slot portions 41. Thereafter, walls 22 of the cam slots 25 urge the ends of the cross pin 60 axially toward the proximal end of the motion control sleeve 40 along the axial slot portions 41. Thus, cam 20 and the motion-control sleeve 40 cooperatively cause the rotational and axial motions of the shaft 50 to take place in sequence, in response to the rotational motion of the lock plug 111 in the latching or clockwise direction, in one continuous motion.

The new latch assembly has been described as mounted on a movable door. This is the preferred location. However, a latch embodying the basic concept of the present invention could be mounted on the fixed cabinet rather than on the door. In such case, the shaft and latch pawl would be moved rotationally to engage a keeper mounted on the inside of the door and then axially away from the first end of the housing 30 to push the door to the tightly closed position. This is the reverse of the axial motion used to pull the door tightly shut when the latch is mounted on the door. When the latch 10 is used in this mode, the closure member will be latched in the counter clockwise direction and unlatched in the clockwise direction. The latching and unlatching directions of the latch 10 can be reversed by simply reversing the pitch of the cam slots 25 and the direction in which the axial slot portions 41 extend relative to the circumferencial slot portions 42. Clockwise and counter clockwise directions as used herein refer to the direction of rotation as perceived by a viewer facing the key hole of the lock plug 111.

It will be recognized by those skilled in the art that changes may be made by the above-described embodiments of the invention without departing from the broad inventive concept thereof. It is understood, therefore, that this invention is not limited to the particular embodiments disclosed, but it is intended to cover all modifications which are within the scope and spirit of the invention as defined by the appended claims.

INDUSTRIAL APPLICABILITY

The present invention is directed to a latch mechanism having wide ranging industrial applicability where ever there is a need to releasably secure a first closure member, such as a door, panel, or the like, relative to a second closure member such as a door, a panel, a compartment, a cabinet, a container, a frame, or the like.

Claims

CLAIMSWe claim:

1. A latch mechanism comprising: a housing having a first end and a second end, said second end of said housing having an opening; means defining at least one motion control slot within said housing in stationary relationship to said housing; a lock plug supported by said housing, said lock plug being selectively rotatable between a latched position and an unlatched position using a key; a cam having at least one cam slot, said cam being rotatably supported within said housing, said cam being coupled to said lock plug so as to rotate in response to rotation of said lock plug; a shaft positioned at least in part within said housing, said shaft extending through said opening in said second end of said housing, said shaft having at least one projection which is engaged at least to both said at least one motion control slot and said at least one cam slot, said at least one motion control slot and said at least one cam slot being configured such that said shaft moves in a sequential combination of substantially axial and substantially rotational motions as said lock plug rotationally moves between said latched and unlatched positions.

2. The latch mechanism according to claim 1, wherein the latch mechanism is for use with a closure member, the closure member is movable between a closed and an open position, and said shaft has a longitudinal axis, the latch mechanism further comprising: a latching member supported by said shaft outside said housing such that said latching member and said shaft move as a unit, said latching member moving between a latched position and an unlatched position in a predetermined sequence of translational and rotational motions in order to selectively, releasably secure the closure member in the closed position, said translational motions being in a direction parallel to said longitudinal axis of said shaft.

3. The latch mechanism according to claim 1, wherein said cam is substantially in the form of a cylindrical sleeve having a wall thickness, said cam slot extends through said wall thickness of said cam, said cam has a distal end and a proximal end relative to said first end of said housing, said cam has a pair of ears extending from said proximal end thereof, and said lock plug has a pair of notches which matingly receive said pair of ears of said cam to thereby allow said cam to move rotationally with said lock plug.

4. The latch mechanism according to claim 3, wherein said cam slot has a proximal end closest to said proximal end of said cam and a distal end farthest from said proximal end of said cam, said cam has a longitudinal axis, and said cam slot has a pitch such that the axial distance, measured in a direction parallel to said longitudinal axis of said cam, between said cam slot and said proximal end of said cam increases in the clockwise direction, beginning at said proximal end of said cam slot, as viewed by a viewer facing said proximal end of said cam.

5. The latch mechanism according to claim 1, wherein the closure member is a first closure member and cooperates with a second closure member, said housing has a flange at said first end thereof, said housing has an exterior surface having interrupted screw threads formed thereon for engagement by a mounting nut for securing said housing in place when said housing is mounted to one of the first closure member and the second closure member.

6. The latch mechanism according to claim 1, wherein said means defining at least one motion control slot is a substantially cylindrical motion control sleeve having said motion control slot formed therein.

7. The latch mechanism according to claim 6, wherein said motion control sleeve has a longitudinal axis, said motion control slot has an axial slot portion extending substantially parallel to said longitudinal axis and a circumferential slot portion, said circumferential slot portion being continuous with said axial slot portion and extending from an end of said axial slot portion in a direction along a length of arc of a circle formed in a plane perpendicular to said longitudinal axis of said motion control sleeve.

8. The latch mechanism according to claim 1, wherein said lock plug is of the type having a key access opening and an array of wafers that retract upon insertion of a key to thereby allow rotational motion of said lock plug under the control of a user.

9. The latch mechanism according to claim 8, further comprising: means defining at least one groove which is engaged by said array of wafers when said array of wafers are not retracted, to thereby prevent rotational motion of said lock plug when said lock plug is in a latched position.

10. The latch mechanism according to claim 9, wherein said means defining at least one groove is a lock plug sleeve having the form of a substantially cylindrical sleeve having an inner surface, said lock plug sleeve having said groove formed on said inner surface.

11. The latch mechanism according to claim 10, wherein the latch mechanism is for use with a closure member, the closure member is movable between a closed and an open position, and said shaft has a longitudinal axis, the latch mechanism further comprising: a latching member supported by said shaft outside said housing such that said latching member and said shaft move as a unit, said latching member moving between a latched position and an unlatched position in a predetermined sequence of translational and rotational motions in order to selectively, releasably secure the closure member in the closed position, said translational motions being in a direction parallel to said longitudinal axis of said shaft.

12. The latch mechanism according to claim 10, wherein said cam is substantially in the form of a cylindrical sleeve having a wall thickness, said cam slot extends through said wall thickness of said cam, said cam has a distal end and a proximal end relative to said first end of said housing, said cam has a pair of ears extending from said proximal end thereof, and said lock plug has a pair of notches which matingly receive said pair of ears of said cam to thereby allow said cam to move rotationally with said lock plug.

13. The latch mechanism according to claim 12, wherein said cam slot has a proximal end closest to said proximal end of said cam and a distal end farthest from said proximal end of said cam, said cam has a longitudinal axis, and said cam slot has a pitch such that the axial distance, measured in a direction parallel to said longitudinal axis of said cam, between said cam slot and said proximal end of said cam increases in the clockwise direction, beginning at said proximal end of said cam slot, as viewed by a viewer facing said proximal end of said cam.

14. The latch mechanism according to claim 10, wherein the closure member is a first closure member and cooperates with a second closure member, said housing has a flange at said first end thereof, said housing has an exterior surface having interrupted screw threads formed thereon for engagement by a mounting nut for securing said housing in place when said housing is mounted to one of the first closure member and the second closure member.

15. The latch mechanism according to claim 10, wherein said means defining at least one motion control slot is a substantially cylindrical motion control sleeve having said motion control slot formed therein.

16. The latch mechanism according to claim 15, wherein said motion control sleeve has a longitudinal axis, said motion control slot has an axial slot portion extending substantially parallel to said longitudinal axis and a circumferential slot portion, said circumferential slot portion being continuous with said axial slot portion and extending from an end of said axial slot portion in a direction along a length of arc of a circle formed in a plane perpendicular to said longitudinal axis of said motion control sleeve.

17. The latch mechanism according to claim 16, wherein said motion control sleeve has a proximal end and a distal end relative to said first end of said housing, said housing has a pair of tabs near said second end thereof and said motion control sleeve has a pair of notches, near said distal end of said motion control sleeve, which are engaged by said pair of tabs to thereby prevent rotation of said motion control sleeve relative to said housing.

18. The latch mechanism according to claim 17, wherein said lock plug sleeve has a proximal end and a distal end relative to said first end of said housing, said lock plug sleeve has a pair of projections extending from said distal end of said lock plug sleeve, said motion control sleeve has a second pair of notches, near said proximal end of said motion control sleeve, which are engaged by said pair of projections of said lock plug sleeve to thereby prevent rotation of said lock plug sleeve relative to said housing.

19. The latch mechanism according to claim 18, wherein said cam is substantially in the form of a cylindrical sleeve having a wall thickness, said cam slot extends through said wall thickness of said cam, said cam has a distal end and a proximal end relative to said first end of said housing, said cam has a pair of ears extending from said proximal end thereof, and said lock plug has a pair of notches which matingly receive said pair of ears of said cam to thereby allow said cam to move rotationally with said lock plug.

20. The latch mechanism according to claim 19, wherein said cam is substantially coaxial with said motion control sleeve.