Latch Assembly

Abstract

A compartment door latch mechanism comprising a housing with a cylindrical bore and a keeper engageable latch bolt externally, pivotally, mounted on the housing for swinging movement between latched and unlatched positions. A pawl and a key cylinder device are separately rotatably mounted within the housing bore. The latch bolt has a cam portion in communication with the rotary pawl through a slot in the housing. The rotary pawl also has a slot in its cylindrical surface which slot is adapted to be brought into alignment with the housing slot by appropriate rotation of the pawl by the key cylinder device. When the two slots are aligned, the latch bolt cam portion moves into the pawl slot and the latch bolt achieves unlatched position. The cam portion otherwise abuts the cylindrical surface of the pawl and the latch bolt is in latched position. The key cylinder device has a lost motion connection with the rotary pawl. The pawl is non-responsive to rotation of the key cylinder device from a first or locked position of the latter to a second or non-locked position but then becomes responsive upon rotation beyond the second position permitting alignment of the slots and unlatching movement of the latch bolt, thereby unlatching the door latch mechanism. Upon subsequent relatching of the latch mechanism, a spring drives only the rotary pawl to a position in which its slot is out of alignment with the housing slot and the latch bolt then again becomes blocked against swinging movement.

Description

BACKGROUND OF THE INVENTION

For many years compartment door latch mechanisms, particularly those used on vehicles glove box doors, have been of the type having a pivotally mounted fork or bifurcated bolt which is actuated to a door releasing or unlatching position upon depression of a push button. Such a latch mechanism is disclosed in U.S. Pat. No. 3,003,348 issued Oct. 10, 1961 to E. N. Jacobi. The push button is locked against movement by a key operated lock cylinder device housed in a bore in the push button.

This arrangement has at least several inherent disadvantages. One of these disadvantages relates to the difficulty of locking the push button against inward latch bolt releasing movement. The act of insertion of the key in the lock cylinder frequently results in the push button being depressed enough to trigger release of the latch bolt and caused undesired unlatching of the glove box door, particularly if the glove box is overstuffed with its contents exerting an opening force on the door. Also, frequently if the glove box door is slammed shut, the mass of the lock cylinder will carry the push button inwardly causing immediately unlatching release of the latch bolt, much to the frustration of the person trying to close the door. And, on a panic or impact stop of the vehicle, the mass of the lock cylinder if in unlocked condition could result in forward movement of the push button and undesired release of the latch bolt causing the door to fly opened on rebound of the vehicle.

The push button type latch mechanisms for glove box doors or the like are now being displaced by a new generation of glove box latch mechanisms. The latch bolt in this type of mechanism is held in latched condition by a rotary pawl or detent coupled to the key cylinder mechanism, the latter also being rotatable in the latch mechanism housing. When a key is inserted in the lock cylinder, the rotary pawl is disengageable from the latch bolt by a twist motion rather than by a push motion. The mass of the lock cylinder is effectively constrained against for and aft movement and cannot cause release of the latch bolt under any of the conditions noted above. Reference is made to U.S. Pat. No. 3,429,153 issued Feb. 25, 1969 to Joseph J. Magyar for the details of such a latch mechanism.

In the Magyar latch mechanism, the entire lock cylinder and its knob is used as a pivoted latch bolt constraining component. Also the locking cylinder and knob are always returned by a spring to a neutral or locked position so that withdrawal of the key from the locking cylinder can occur only when the glove box door is latched and locked.

It is an object of the present invention to provide a rotary glove box latch mechanism in which the pivotal latch bolt restraining component is a separate rotary pawl, i.e., the pawl is separate from the locking cylinder. The reduced mass of the separate pawl insures positive latching of the latch bolt during the over-slam of closing the door. A secondary benefit derived from this concept is a lower rotary operating effort since the spring used to return the pawl to a predetermined locking position can be designed with lower output forces. The smaller rotary pawl does not require the spring force required in any concept that utilized the complete lock cylinder and knob as a rotary pawl.

It is a further object to provide a rotary latch mechanism in which the key can be actuated and removed with the latch mechanism in a locked or unlocked condition. This is achieved by a free or lost motion connection between the lock cylinder and the pawl.

SUMMARY OF THE INVENTION

The present invention relates to a compartment door latch mechanism comprising a housing having a cylindrical bore therein. A keeper device engageable latch bolt is pivotally mounted on the housing externally thereof for swinging movement between latched and unlatched positions in a plane parallel to the longitudinal axis of the cylindrical bore. A rotary pawl is mounted in the cylindrical bore for rotation about the longitudinal axis of the bore. The rotary pawl has a longitudinally extending slot therein. The latch bolt has a cam portion adapted to communicate with the rotary pawl through a slot in the housing. The cam portion in latched position of the latch bolt abuts a surface of the rotary pawl to block unlatching movement of the latch bolt. The rotary pawl has a slot adapted to be positioned in alignment with the housing slot. A key cylinder means is rotatably seated in the cylindrical bore and is key rotatable between a first or locked and a second or unlocked position. The key cylinder means and the rotary pawl have a lost motion connection therebetween with the rotary pawl being non-responsive to movement of the key cylinder means between the first and second positions of the latter. The key cylinder means is operable, however, when moved beyond the second or unlocked position to rotate the rotary pawl from latched bolt blocking position to a position in which the cam portion and the rotary pawl slot are aligned whereby the cam portion is movable into and is received within the pawl slot as the latch bolt moves to unlatched position. A first and a second spring means respectively bias the rotary pawl toward slot and cam portion nonalignment relationship and the key cylinder means to unlocked position after movement beyond the unlocked position.

Except for the lost motion connection therebetween, the rotary pawl and the key cylinder means are longitudinally spaced from each other within the housing bore. The first spring means for biasing the rotary pawl toward latch bolt blocking position is located between the base of the bore and the contiguous end of the rotary pawl. The second spring means is located between the rotary pawl and the key cylinder means.

DESCRIPTION OF THE DRAWINGS

Further features and advantages of the present invention will be explained in greater detail making reference to the description which now follows, reference being had to the drawings in which:

FIG. 1 is a vertical cross section view of a portion of a vehicle instrument panel and the glove compartment door mounted therein;

FIG. 2 is an end view of FIG. 1 looking from the inside of the compartment outwardly or in the direction of the arrow 2;

FIG. 3 is a section view on the line 3--3 of FIG. 2;

FIG. 4 is a section view on the line 4--4 of FIG. 3;

FIG. 5 is a section view on the line 5--5 of FIG. 3;

FIG. 6 is a section view on the line 6--6 of FIG. 4;

FIG. 7 is a section view on the line 7--7 of FIG. 3; and

FIG. 8 is a section view on the line 8--8 of FIG. 4.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to FIG. 1, the compartment door latch mechanism, generally designated 10, embodying the present invention is illustrated as being mounted on a glove box door 11 forming a closure for an opening in a vehicle instrument panel 12. The door 11 is hingedly supported at its lower edge on hinge devices 13 attached to structural member 14 of the instrument panel 12.

The glove box door preferably is of double wall construction having an inner wall 15 and an outer wall 16. The inner and outer walls are provided with aligned apertures 17 and 18 through which parts of the latch mechanism 10 are adapted to project.

The latch mechanism 10 comprises an elongated generally cylindrical housing 19 having a longitudinally extending internal bore 21. Projecting laterally from the housing exterior, in a plane normal to the longitudinal axis of the bore 21, are flanges 22 apertured at 23 to receive bolts 24 for attaching the housing to the inner wall 15 of the glove box door 11.

A keeper engageable latch bolt 25 is externally mounted on the housing 19. The housing 19 has on its upper surface a pair of spaced upstanding ears 26 (see FIG. 7) that support a pivot shaft 27 on which the latch bolt 25 is secured. The latch bolt 25 is a bifurcated or forked stamping that is cooperable with the base 28 of a generally U-shaped bar striker or keeper 29. The keeper 29 is attached by bolts 31 and nuts 32 to a support flange 33 internally of the instrument panel 12. The latch bolt 25 has a cam portion 34 in communication with the housing bore 21 through a longitudinally extending slot 35, for a purpose to become apparent. A coil torsion spring 36 winds about the pivot shaft 27 on both sides of the latch bolt 25 and has a connecting looped portion 37 hooked over a tang 38 on the bolt. The free ends 39 of each coil bears against the housing and bias the latch bolt 25 toward unlatched position, i.e., the solid line position to the dotted line position shown in FIG. 3. The latch bolt 25 is partially encased in a protective U-shaped housing 41 with the "U" lying on its side and the upper leg 42 extending beyond a vertical line through the axis of pivotal movement of the latch bolt 25.

It will be noted that the looped portions of the spring 37 intrude between the tines of the forked latch bolt. This provides an anti-rattle device between the latch bolt 25 and the base bar 28 of the keeper 29.

Contained within the bore 21 of the housing 19 is a relatively short cylindrical member which hereinafter will be referred to s a rotary pawl 43. The cam portion 34 of the latch bolt 25 is in communication with the rotary pawl 43 through the housing slot 35. As shown in solid outline in FIG. 3, the lower corner 34a of the cam portion 35 is in abutting engagement with the cylindrical surface of the rotary pawl 43. In this relationship, the latch bolt 25 is held in latched position, as shown in FIG. 1.

As best seen in FIG. 7, the rotary pawl 43 has a longitudinally extending slot 44 which is adapted under controlled conditions to be aligned with the housing slot 35 and therefore with the cam portion 34 of the latch bolt 25. Whenever this aligned condition is achieved, the coil torsion spring 36 becomes operative to drive the latch bolt 25 in an unlatching direction, i.e., counterclockwise from the solid outline position shown in FIG. 3 to the dot and dash outline position.

The mechanism for driving the rotary pawl 43 in counterclockwise or unlatching direction is a key cylinder device, generally designated 45. The key cylinder device 45 comprises an elongated cylindrical body or barrel 46 having intermediate its ends a plurality of spring-loaded (springs 47) plate-type locking elements 48. The locking elements 48 in the absence of a key 49 extend beyond the surface of the barrel 46 into a longitudinally extending recess 51 in the housing 19, see FIG. 5, thereby holding the barrel against rotation in the cylindrical bore of the housing. When the proper coded key 49 is inserted in the key slot 52 on the end 53 of the barrel 46 it projects outwardly from the housing 19, the locking elements retract into the barrel and the latter is rotatable by the key 49. A knurled assist knob 54 is provided to assist in turning the barrel 46 or for rotating the latter when the key 49 is withdrawn under certain conditions, as will be explained. The key barrel 46 is held within the bore 21 of the housing 19 by a staked retention plate 55.

An important feature of the present invention is that the rotary pawl 43 and the key cylinder device barrel 46 are mounted in the housing bore 21 as separate components which are drivingly coupled to each other through a lost motion connection. The pawl 43 has in its end face 56 contiguous the end face 57 of the key cylinder barrel 46 a semi-circular recess 58. The barrel 46 has two axially extending projections 59 and 61 that are substantially diametrically opposed to each other. The projection 59 is the longer of the two and projects into the pawl recess 58. The face 62 of the projection 59 is adapted to abut the flat wall 63 of the recess 58 upon rotation of the key barrel in a clockwise direction, as viewed in FIG. 6. At the same time, the face 64 of the shorter projection 61 is adapted to abut the face 65 of an axially extending tab 66 on the rotary pawl 43. It will be noted that about 90.degree. of lost motion rotation must occur before the projections 59 and 61 abut the pawl surfaces 62 and 64, respectively. Continued clockwise movement of the key barrel 46 beyond the point at which the projections 59 and 61 abut the pawl surfaces 63 and 65 causes the pawl 43 to be rotated in a direction to bring the slot 44 into alignment with the cam portion 34 of the latch bolt 25, as can be readily visualized with reference to FIG. 7.

The rotary pawl 43 and the key barrel 46 are under the biasing influence of separate springs 67 and 68, respectively. The pawl spring 67 is a coil spring interposed between the bottom wall 69 of the housing bore 21 and the adjacent end face 71 of the pawl 43. The spring 67 has a hook portion 72 at one free end hooked over an edge 73 of an aperture in the housing 19. At its inner end, the spring 67 has a straight end portion 74 fitted through a diametrical slot 75 and extending into a clearance slot 76 in the side wall of the housing 19.

When the rotary pawl 43 is rotated by the key device 45 in a clockwise direction, as viewed in FIGS. 7 and 8, to bring the slot 44 into alignment with the latch bolt 25, the spring 67 is wound up. Upon the latch bolt 25 being rotated in latching direction, as upon engagement with striker or keeper 29, the spring 67 becomes effective to bias the pawl back to the latch bolt locking position.

The spring 68 acts only on the key barrel 46. It also is a coil spring and is interposed coaxially between the opposed end faces 56 and 57 of the rotary pawl 43 and the key barrel 46. As best seen in FIG. 6, it has a hook 77 at one free end which is hooked over an aperture edge 78 in the wall of the housing 19.

The free end of the spring toward the key barrel face 57 is an elongated straight section 79 which may be considered as lying across the end of the pawl tab 76 and projecting upwardly into a slot 81 in the wall of the housing 19.

As will be explained more fully, the spring 68 offers no resistance to rotation of the key barrel 46 during approximately the first 90.degree. of movement of the latter or during the period in which rotation of the key barrel does not cause responsive rotation of the rotary pawl 43 because of the lost motion connection therebetween. It is only after the projection 59 on the end of the key barrel 46 abuts the face 63 of the rotary pawl 43 to cause the latter to rotate that the biasing force of the barrel spring 68 comes into play. The projection 59 on the key barrel 46 abuts the straight section 79 of the barrel spring 68 and causes the spring to become wound up.

Upon release of the pressure causing the key barrel to rotate, the barrel spring 68 restores the key barrel 46 to the position in which it was just prior to causing responsive rotation of the rotary pawl 43.

Suitable stops (not shown) are provided between the key barrel 46 and the housing 19 that define the range of movement through which the key barrel may be rotated either by the key 49 or by turning of the knob 54.

OPERATION OF THE LATCH MECHANISM

Referring now to FIGS. 1 and 3, the latch bolt 25 of the latch mechanism 10 is shown in latched position relative to the striker or keeper 29. The lower edge 34a of the cam portion 34 of the latch bolt is in abutting relation to the cylindrical surface of the rotary pawl 43. The latch bolt is under a biasing force from the spring 36 which is urging the latch bolt in a counterclockwise direction as viewed in FIG. 3 which movement is blocked by the rotary pawl 43. Upon insertion of the key 49 in the key barrel 46, the plate-type locking elements 48 carried by the key barrel are retracted against the biasing forces of the respective springs 47 and the locking elements are retracted into the barrel. In other words, the locking elements 48 are withdrawn from the recess 51 in the housing 19 and the barrel then becomes rotatable within the housing, as may best be visualized with reference to FIG. 5.

During the first substantially 90.degree. movement in a clockwise direction, as viewed in FIG. 5, rotation of the key barrel 46 is not transmitted to any of the latch mechanism components. At the end of the 90.degree. rotation, the only thing that happens is that the locking elements 48 become aligned with a recess 82 in the side wall of the housing 19, see FIG. 5. At this point, if desired, the key may be withdrawn from the key slot 52 in the key barrel 46. The only thing that would happen is that the respective locking plates would move outwardly from the key barrel 46 until they abut the circular wall of the side recess 82. The latch mechanism 10 still would not be in a condition to permit unlatching movement of the latch bolt 25. The key barrel 46 must be rotated in the clockwise direction an additional 30.degree. to 45.degree.. Upon this further rotation of the key barrel 46, the face of the projection 59 abuts the face 63 of the recess 51 in the rotary pawl 43 causing the latter to rotate in a clockwise direction, as visualized in FIG. 7, to bring the slot 44 in alignment with the slot 35 in the housing and with the cam portion 34 of the latch bolt 25. As soon as the proper alignment is achieved, the spring 36 causes the latch bolt 25 to rotate in a counterclockwise direction as viewed in FIG. 3 through the dot and dash outline position. In this condition the latch mechanism is unlatched. As soon as the key 49 or the knob 54 is released, the key barrel 46 returns to substantially the 90.degree. position. The rotary pawl 43, however, because of the interlock that now exists between the rotary cam portion 34 of the latch bolt 25 and the walls of the slot 44 is held against being restored to its original or latch bolt locking position.

Upon the compartment door being slammed shut so that the latch bolt 25 engages the striker or keeper 29, the latch bolt is rotated in a direction to move its cam portion 34 out of the slot 44. Upon disengagement, the spring 67 becomes effective to rotate the rotary pawl 43 back to its original or latch bolt locking position. If the key 49 has been withdrawn from the key slot 52 in the key barrel 46, the latch mechanism is in a latched but unlocked condition. To unlatch the latch bolt it is only necessary to grasp the knurled knob 54 and rotate the same in the counterclockwise direction as viewed in FIG. 5 until it picks up the rotary pawl and causes the latter to rotate to unlatched position. It is impossible to rotate the key barrel 46 in a clockwise direction back to the zero position because the edges of the locking elements 48 are in abutting relation to the stepped wall of the recess 82. To get the key barrel 46 back to the 0.degree. or locked condition, it is necessary that the key 49 be in the key slot 52 or be reinserted in the slot 52 so that the locking elements 48 is retracted into the key barrel 46. It is necessary to manually rotate the key barrel 46 back to the zero position because the spring 68 exerts no biasing force on the key barrel 46 from the 90.degree. to the 0.degree. position.

It will be noted that the rotary pawl 43 of itself is of insignificant mass and is easily restored by a relatively light spring 67 from latch bolt unblocking position to latch bolt blocking position. The reduced mass of this pawl insures positive latching of latch bolt during the brief period of overslam of closing the door. A secondary benefit is that since the key barrel spring 68 offers no resistance to unlocking movement of the key barrel during the 90.degree. of movement of the latter, it too can be a relatively light spring. The resistance of both of the springs 67 and 68 to turning movement is less than would be required if the pawl 43 and the key barrel 46 were a single unit biased to latch bolt blocking position by a single heavier spring.

It will be understood that the invention is not to be limited to the exact construction shown and described, but that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the appended claims.

Claims

We claim:

1. A compartment door latch mechanism comprising:

a housing having a cylindrical bore therein,

a keeper device engageable latch bolt,

pivot means externally mounting the latch bolt on the housing for swinging movement between latched and unlatched positions,

a rotary pawl mounted in the cylindrical bore,

a cam portion on the latch bolt in communication with the rotary pawl through a slot in the housing,

the cam portion in latched position of the latch bolt abutting a surface of the rotary pawl to block unlatching movement of the latch bolt,

the rotary pawl having a slot positioned for alignment with the housing slot,

key cylinder means rotatably seated in the cylindrical bore and key rotatable between first and second positions,

the key cylinder means and the rotary pawl having a lost motion connection therebetween with the rotary pawl being nonresponsive to movement of the key cylinder means between its first and second positions,

the key cylinder means being operable when moved beyond the second position to rotate the rotary pawl from latch bolt blocking position to a position in which the cam portion and rotary pawl slot are aligned whereby the cam portion is received within the pawl slot as the latch bolt moves to unlatched position,

a first spring means biasing the rotary pawl toward latch bolt blocking position,

and a second spring means restoring the key cylinder means to the second position after movement therebeyond.

2. A compartment door latch mechanism according to claim 1, in which:

the latch bolt is swingable in a plane parallel to the longitudinal axis of the cylindrical bore,

and the slot in the housing parallels the cylindrical bore longitudinal axis.

3. A compartment door latch mechanism according to claim 2, in which:

the first spring means is positioned between the base of the bore and the contiguous end of the rotary pawl,

and the second spring means is positioned between the rotary pawl and the key cylinder means.

4. A compartment door latch mechanism according to claim 3, in which:

the key cylinder means includes a key insertable or withdrawable in either the first or second positions.

5. A compartment door latch mechanism according to claim 1, in which:

the first spring means is positioned between the base of the bore and the contiguous end of the rotary pawl,

and the second spring means is positioned between the rotary pawl and the key cylinder means.

6. A compartment door latch mechanism according to claim 5, in which:

the key cylinder means includes a key insertable or withdrawable in either the first or second positions.

7. A compartment door latch mechanism according to claim 1, in which:

the key cylinder means is operable by a key which is insertable or withdrawable in both the first and second positions.

8. A compartment door latch mechanism according to claim 1, in which:

the latch bolt is urged by spring means toward unlatched position so that the cam portion thereof is biased into the rotary pawl slot upon the latter being aligned with the housing slot upon rotation of the rotary pawl by the key cylinder means.

9. A compartment door latch mechanism having:

a housing with an elongated cylindrical bore therein,

a keeper device engageable latch bolt pivotally mounted on the housing externally thereof for swinging movement between latched and unlatched positions in a plane parallel to the longitudinal axis of the cylindrical bore,

a rotary pawl mounted in the cylindrical bore for rotation about the longitudinal axis thereof and having a longitudinally extending slot therein,

the latch bolt having a cam portion thereon adapted to communicate with the rotary pawl through a slot in the housing,

the housing slot also paralleling the cylindrical bore longitudinal axis,

in unlatched position of the latch bolt the cam portion projecting through the housing slot into the rotary pawl slot and in latched position the cam portion projecting through the housing slot and abutting the peripheral surface of the rotary pawl,

key cylinder means for rotating the rotary pawl to align the pawl slot with the latch bolt cam portion,

and spring means urging the latch bolt toward unlatched position so that the cam portion will drop into the rotary pawl slot upon the latter being aligned with the housing slot,

wherein the improvement comprises:

the rotary pawl being independent of and longitudinally spaced from the key cylinder means,

the key cylinder means being key rotatable between a locked and an unlocked position,

the key cylinder means and the rotary pawl having a lost motion connection therebetween with the rotary pawl being nonresponsive to the key cylinder means between its locked and unlocked positions,

the key cylinder means being operable when rotated beyond the unlocked position to rotate the rotary pawl into alignment with the housing slot and latch bolt cam portion,

and first and second spring means respectively biasing the rotary pawl toward slot and cam portion non-alignment relationship and the key cylinder means to unlocked position after movement therebeyond.

10. A compartment door latch mechanism according to claim 2, in which:

the first spring means is positioned between the base of the bore and the contiguous end of the rotary pawl,

and the second spring means is positioned between the rotary pawl and the key cylinder means.