Locking mechanism

BACKGROUND OF THE INVENTON

1. Field of the Invention

The present invention pertains to a locking mechanism and more particularly to a locking mechanism that requires unlatching as well as unlocking prior to opening thereof.

2. Description of the Prior Art

Locking mechanisms requiring both unlocking and unlatching to permit movement of a panel away from a stationary wall are well known; however, in the past such locking mechanisms have been relatively complex and expensive to produce. More specifically, conventional locking mechanisms of the type above described normally have a relatively large number of parts pivotal or otherwise movable in response to axial displacement of a lock cylinder. The large number of movable parts is disadvantageous in that production expenses are increased and the locking mechanisms are subject to breakage and malfunction.

Another disadvantage with conventional locking mechanisms is that after unlocking an inwardly directed force is applied to the lock cylinder to unlatch the mechanism and thereafter the panel must be manually moved away from the wall. That is, a force which is normally opposite to the inwardly directed force is required to unlatch the locking mechanism, and this requirement is often quite burdensome and awkward.

SUMMARY OF THE INVENTION

The present invention is generally summarized in a locking mechanism for controlling the closure of a movable panel with a stationary wall including a mounting member secured to the panel and having a bore therethrough communicating with a housing, a key operable lock slidably disposed in the bore and coupled with a pawl rotatably disposed in the housing, and a latching arm secured to the stationary wall and having a portion engaging the housing to maintain the locking mechanism in a latched state, the pawl being movable when in an unlocked position to disengage the latching arm from the housing to place the locking mechanism in an unlatched state.

It is an object of the present invention to utilize a minimum number of moving parts in a locking mechanism requiring both unlocking and unlatching for opening thereof.

Another object of the present invention is to construct a locking mechanism that is maintained in a latched condition regardless of the position of a key operable lock.

A further object of the present invention is to provide a locking mechanism which automatically opens after being unlatched by an inwardly directed force on a key operable lock.

Some of the advantages of the locking mechanism of the present invention over the prior art are that the locking mechanism is inexpensively produced with a minimum number of moving parts and the locking mechanism opens automatically after unlatching.

Further objects and advantages of the present invention will become apparent from the following description of the preferred embodiment taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view partially in section of a locking mechanism in accordance with the present invention.

FIG. 2 is a section taken along line 2—2 of FIG. 1.

FIG. 3 is a view taken along line 3—3 of FIG. 1.

FIG. 4 is a plan view of the locking mechanism of FIG. 1 in an unlatched state.

DESCRIPTION OF THE PREFERRED EMBODIMENT

A locking mechanism 10 for controlling the closure of a movable panel 12 with a stationary wall 14 is illustrated in FIG. 1 through 4 and includes a mounting member 16 secured in a recess 18 in the inner surface of panel 12 by means of a mounting flange 20. Mounting member 16 has a bore 22 housing a lock cylinder 24 which is axially slidable therein and extends through a bore 26 in panel 12. Lock cylinder 24 has a 5 collar collar 28 therearound abutting an annular shoulder 30 in bore 26 under the force from a helical bias spring 22 mounted in compression between collar 28 and an annular shoulder 34 in mounting member 16.

A key plug 36 extends through lock cylinder 24 to an en^lu larged face 38 which is positioned flush with a counterbored escutcheon 40 in the outer surface of panel 12. Key plug 36 has a slot therein adapted to receive a key corresponding to tumblers carried by lock cylinder 24 to permit key plug 36 to 15 ^{turn w}’^tb*ⁿ 1°*-^ cylinder, as is conventional. An inner end 42 of key plug 36 is secured inside a cylindrical coupling member 44 by means of a roll pin 46. Coupling member 44 is journaled through mounting member 16 and is secured to an L-shaped pawl 48 by a bolt 50. Pawl 48 has a locking control 20 leg 52 extending transversely from a latching control leg 54 which has a beveled edge 56. A keeper plate 58 is mounted on wall 14 adjacent pawl 48 such that leg 52 is engageable therewith.

Mounting member 16 carries a latch housing 60 which in25 eludes an arcuate sidewall 62 having a skirt 64 at an end portion thereof and terminating in an annular head 66. Wall 62 is cut away around its base at 68 to receive pawl 48, and a longitudinal slot 70 having a width slightly greater than the width of leg 54 of pawl 48 is provided in wall 62 facing keeper plate 30 58. A longitudinal slot 72 in wall 62 is spaced 90° from slot 70 and has a width slightly greater than the width of leg 52 of pawl 48. Pawl 48 has an unlocked position in which leg 52 is positioned under slot 72 and leg 54 is positioned under slot 70 and a locked position in which leg 54 abuts a stop edge 74 of 35 wall 62 and leg 52 engages keeper plate 58.

A latching spring arm 76 is secured by means of a block 78 to wall 14 and has an angularly offset T-shaped end 80. Latching arm 76 is positioned such that the stem of end 80 is aligned in slot 70 and the transverse legs of end 80 engage the 40 protruding edge formed by the underside of skirt 64. A bias spring member 82 is mounted on wall 14 with block 78 and is bifurcated to provide spring arms 84 and 86 each of which has an offset end engaging head 66 at the end of housing 60.

The locking mechanism 10 of the present invention is illus⁴⁵ trated in its latched state in FIG. 1. The position of pawl 48 is controlled by a key inserted in key plug 36 such that pawl 48 is movable through a 90° arc. Thus, if it is desired to place the locking mechanism 10 in a locked state, the key is inserted in ₅₀ key plug 36 and rotated clockwise, looking at FIG. 2, until leg 54 abuts stop 74. Leg 52 is thus positioned to engage keeper plate 58, as illustrated in phantom in FIGS. 1 and 2; and, locking mechanism 10 prevents movement of panel 12 away from wall 14 due to the locked position of pawl 48 and the en55 gagement of latching arm 76 with the protruding edge of skirt 64.

To open the locking mechanism 10, the key is inserted in key plug 36 and rotated counterclockwise, looking at FIG. 2, to move pawl 48 to its unlocked position in which leg 52 is ¢0 aligned with slot 72 and leg 54 is aligned with slot 70 and latching arm 76. The panel 12 cannot as yet be moved away from wall 14 due to latching arm 76 being in its latched position; however, once pawl 48 is in its unlocked position, an inwardly directed force on face 38 acts to move lock cylinder 24 65 axially within bore 22 against the force of bias spring 32 to permit opening of the locking mechanism as follows. Axial movement of lock cylinder 24 moves pawl 48 towards top 66 of housing 60, with such movement being freely permitted since legs 52 and 54 of pawl 48 are aligned with slots 72 and 70 70, respectively. The movement of leg 54 of pawl 48 causes beveled edge 56 of leg 54 to engage offset, T-shaped end 80 of latching arm 76 to move end 80 laterally away from the protruding edge of skirt 64 to its unlatched position, as illustrated in FIG. 4. Once latching arm 76 is moved to its un75 latched position, the force from bias member 82 on the end of

3,602,017 housing 60 will automatically force the housing away from wall 14 to open panel 12.

Axial movement of lock cylinder 24 and pawl 48 is prevented when the pawl is in any position other than its unlocked position due to the abutment of pawl 48 with wall 62 of housing 60. That is, unless pawl 48 is positioned such that legs 50 and 52 are aligned with slots 72 and 70, respectively, pawl 48 cannot be axially displaced.

Upon closure of panel 12, head 66 of housing 60 first engages bias member 8; and, upon applying pressure on panel 12, housing 60 is moved up against the force of member 8 until latching arm 76 is placed in its latched position engaging the protruding edge of skirt 64. The offset end 80 of latching arm 76 permits the latching arm to engage skirt 64 and be moved laterally outwardly until panel 12 is closed and end 80 has moved past the protruding edge of skirt 64 such that latching arm 76 snaps into slot 70 to assume its latched position.

It may be seen that the only moving parts in the locking mechanism of the present invention are the conventional key operable lock and the pawl; and, accordingly, the components of the locking mechanism may be inexpensively formed and assembled. The alignment of latching arm 76 with slot 70 of housing 60 and the angular orientation of beveled edge 56 of leg 54 of pawl 48, end 80 of latching arm 76, and skirt 64 permit smooth cooperation to facilitate secure latching and unlatching of the locking mechanism and to obviate the necessity of moving latching parts.

Inasmuch as the present invention is subject to many variations, modifications and changes in detail, it is intended that all matter contained in the foregoing description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.