Door lock mechanism

Abstract

A door lock mechanism includes a rotatable latch engageable with a striker, first and second pawls engageable with the latch so as to thereby maintain the latch at its locking position, exterior and interior door opening means for releasing the engaging components of the first and second pawls and the latch, and means responsive to the rotation of the second pawl upon closing of the door to thereby limit the door opening movement of the interior door opening means.

Description

BACKGROUND OF THE INVENTION

The present invention relates generally to door lock mechanisms and more particularly to a door lock mechanism for a motor vehicle which includes means for preventing an interiorly located door opening mechanism from being operated, especially by a child, when the door is closed.

SUMMARY OF THE INVENTION

One object of the present invention is to provide an improved door lock mechanism which serves to prevent, or at least minimize the possibility of accidents involving a child or children in the vehicle, the door lock mechanism including a child-proof means responsive to the closing movement of a vehicle door so as to thereby limit or prevent the operation of the interior door opening means as long as the door is closed, such closed position hereinafter referred to as the "child-proof condition, characteristic, or position." In this manner, the door cannot be opened even when the children act mischievously and attempt to operate the interior opening means, and consequently accidents involving children falling from the vehicle while the vehicle is travelling, or when the children will run out of the vehicle while the same is not moving and possibly be injured by another vehicle, will be prevented.

Another object of the present invention is to provide an improved door lock mechanism wherein the door can be opened by the door opening operation of an exterior opening means when the door lock mechanism is in its child-proof condition, so that the children which have suffered accidents within the vehicle can be released from the vehicle by persons outside the vehicle.

Still another object of the present invention is to provide an improved door lock mechanism wherein the door lock mechanism exhibits the child proof characteristic involving a cancelling operation and wherein a keyless locking operation of the door lock mechanism may be obtained.

The foregoing objectives are achieved according to the present invention through the provision of a lock mechanism which includes a latch which engages with two pawls in the full locking position, a locking means which is displaced in an intermediate or third position between locking and unlocking positions by the movement of the second pawl in response to the door closing movement and a child-proof means which is displaced by the movement of the second pawl in a position in which the operation of the interior door opening means is prevented or limited and the child-proof condition is obtained. The latch engages the two pawls in the full locking position so that the strength at the engaging points between the latch and the pawls will be increased, substantially two times, such that even when an abnormal force, which intends to open the door, such as when due to collisions, will be characteristic of the engaging means.

BRIEF DESCRIPTION OF THE DRAWINGS

Various other objects, features and attendant advantages of the present invention will be more fully appreciated as the same becomes better understood from the following detailed description when considered in connection with the accompanying drawings, in which like reference characters designate like or corresponding parts throughout the several views, and wherein:

FIG. 1 is a front view of the door locking mechanism constructed according to the present invention and showing its cooperative engaging parts when the door is open, the cover plate being omitted;

FIG. 2 is a view similar to that of FIG. 1, showing however the closed condition of the door;

FIG. 3 is a rear view of an operating mechanism of the door lock mechanism constructed according to the present invention when the operating mechanism is in its unlocked position;

FIG. 4 is a schematic view of an interior opening lever;

FIG. 5 is a view similar to that of FIG. 4 showing however an exterior opening lever;

FIG. 6 is a cross-sectional view of the operating mechanism shown in FIG. 3 taken along the line VI--VI of FIG. 3;

FIG. 7 is a side view of the door lock mechanism constructed according to the present invention when the door lock mechanism is in its unlocked position;

FIGS. 8 and 9 are partial views of the operating mechanism showing means which prevents or limits the operation of the interior lever;

FIG. 10 is a view similar to that of FIG. 3 showing however the operating mechanism in its inoperative and child-proof condition;

FIG. 11 is a view similar to that of FIG. 3 showing however the operating mechanism in its locked condition; and

FIGS. 12, 13 and 14 are views showing another embodiment of the present invention which includes the means which prevent or limit the operation of the interior lever.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to the drawings, and more particularly to FIGS. 1-11 thereof, a striker 11 is of a conventional U-shaped configuration and is, at both end or leg portions, secured to a door pillar of the vehicle. A head portion of the striker 11 which is disposed parallel to the door pillar cooperates with a door lock mechanism, generally indicated by the reference character 10 so as to maintain the engagement therebetween even when the vehicle body is jolted or shocked in a longitudinal direction. A door lock body 12, which may be made of a synthetic resin, has a plurality of recessed portions 12a, 12b and 12c, a fork-type latch 14, disposed within the recessed portion 12a, being pivotably supported about an axle 13, while a first pawl 16 is disposed within the recessed portion 12b and is pivotably supported about an axle 15, and a second pawl 18 is pivotably supported within the recessed portion 12c about the axle 17.

The latch 14 includes a striker-receiving recess 14a which is adapted for engagingly receiving an engaging portion 11a of the striker 11, first and second ratchet teeth 14b and 14c which are adapted to engage with an engaging pawl portion 16a in a safety locking position and a full locking position, respectively, and a third ratchet tooth 14d which is also adapted to engage with an engaging pawl portion 18a of the pawl 18 in the full locking position, the second and third ratchet teeth 14c and 14d being substantially symmetrically positioned relative to the axis 13 upon diametrically opposite sides thereof. The latch 14 is integrally connected with the axle 13 so that both components are adapted to be rotated as a single unit, the axle-latch mechanism being normally urged in a counter-clockwise direction, as seen in FIG. 1, by means of a spring, not shown, interposed between the axle 13 and the door lock body 12.

A spring 19 is similarly interposed between an arm portion 16b of the first pawl 16 and the body 12 so as to normally bias the first pawl 16 in a clockwise direction, as seen in FIG. 1, while another spring 20 is likewise interposed between an arm portion 18b of the second pawl 18 and the body 12 so as to also normally bias the second pawl 18 in a clockwise direction as seen in FIG. 1. A pin 21 is rigidly mounted, at one end thereof, upon the first pawl 16 and extends or projects toward the rear side of the body 12 so as to be accommodated within an elongated groove 12d of the body 12, and another pin 22 is similarly mounted upon an arm portion 18c of the second pawl 18 so as to extend and project, toward the other side of the body 12, through an elongated groove 12e provided within the body 12. The second pawl 18 also has a rightwardly extending arm 18d which is adapted for engagingly contacting an arm portion 45a of a first blocking lever 45 whereby the arm 45a of the blocking lever 45 may be shifted upwardly as seen in FIG. 1 upon rotation of the second pawl 18 in a counterclockwise direction, as will be more apparent hereinafter.

Referring more particularly to FIG. 3, a base plate 25 is secured to the other or rear side of the body 12 and includes a primary base plate 25a and a secondary base plate 25b which extends vertically as may also be seen in FIG. 6. A substantially L-shaped opening lift lever 26 is pivotally supported upon the other end of the axle 15 which extends through the body 12, a right arm 26a of the opening lift lever 26 having the other end of the pin 21 secured thereto, while a flanged portion 26b of the arm 26a extends vertically. Another arm portion 26c of the opening lift lever 26 also extends vertically so as to complete the L-shaped configuration of lever 26 in conjunction with arm 26a and is seen to include a surface which extends parallel to that of the arm 26a, a flanged portion 26d of the arm 26c extending horizontally. Both of the arm flanges 26b and 26d are arranged and designed so as to selectively and respectively engage first and second engaging portions 28a and 28b of an opening link 28, as will be more apparent hereinafter.

Pivotally mounted upon the primary base plate 25a, through the axle 17, is an interior opening lever 30 which has arm portions 30a and 30d, the arm portion 30a being provided with elongated apertures 30b and 30c, as shown in FIG. 4. An exterior opening lever 31 is disposed upon the interior opening lever, as seen in FIGS. 3 and 6, and is also pivotally mounted upon the axle 17, the exterior opening lever 31 being similarly provided with an elongated aperture 31a and a substantially circular aperture 31b within which a pin 33 is secured, as shown in FIG. 6. Thus, these levers 30 and 31 are arranged coaxially with the second pawl 18.

The elongated holes 30b and 31a have the same configuration and size and are positioned at equal distances from the pivotal axis of levers 30 and 31, and therefore, these holes 30b and 31a are completely overlapped under assembled conditions. The pin 22 is consequently adapted to be slidably mounted within the holes 30b and 31a, and as will be clear from FIG. 6, the pin 33, which is secured within the hole 31b of the exterior opening lever 31 and the upper end of aperture 30c of lever 30, has a flanged end for rotatably supporting and retaining opening link 28 as well as an exterior opening rod 34 which is operatively connected to an exterior opening handle, not shown. The arm 30d of the interior opening lever 30 extends through an elongated hole 25c provided within the secondary base plate 25b, as shown in FIG. 7, the rotation of the arm 30d about the axle 17 thus being limited by the length of the aperture 25c.

Still referring to FIGS. 3 and 7, a longitudinally extending locking plate 35 and a laterally extending locking stopper plate 36 are pivotally mounted upon the primary base plate 25a through means of a pin 37, the upper head portion 35a of the locking plate 35 being flanged so as to be slidably disposed and secured within an elongated hole 28c formed within the opening link 28. A turn-over spring 38 is interposed between the lower end of the locking plate 35 and the primary base plate 25a and serves to bias the locking plate 35 toward a location at which the rotatable movement of the locking plate 35 is limited by means of a stopper 25d secured upon the primary base plate 25a.

The upper edge of the locking stopper plate 36 is provided with a pair of motion transmitting portions or members 36a and 36b which are horizontally extending flanges which serve to retain the locking plate 35 therebetween. The left arm 36c of the locking stopper plate 36 has a pin 39 secured thereto which is selectively engaged with one of three concaved portions 40a, 40b and 40c of a spring 40 whereby the position of the locking stopper plate 36 may be determined, the other end of the spring 40 being engaged with a pin 41 secured upon the primary base plate 25a. The lower end of a blocking rod 42 is pivotally mounted upon the arm 36c by means of a pin, not numbered, and the lower end of a key rod 43 is pivotally mounted upon the right arm 36d of the locking stopper plate 36, key rod 43 being operatively connected to a key cylinder, not shown.

As seen in FIG. 7, first and second blocking levers 45 and 46 are pivotally mounted upon the secondary base plate 25b through means of a pin 44, the first blocking lever 45 being arranged upon the side of the secondary base plate 25b, as shown in FIG. 6, such that the head 45a of the first blocking lever 45 passes through the door lock body 12 so as to extend over the second pawl 18 and be engaged with the arm 18d of the second pawl 18, as seen in FIGS. 1 and 6. Interposed between the levers 45 and 46 is a spring 47 for biasing the first blocking lever 45 in a counterclockwise direction and for biasing the second blocking lever 46 in a clockwise direction. As a result of such biasing forces, an engaging portion 46a of the second blocking lever 46 is forced to engage the upper surface of the right arm 45b of the first blocking lever 45, and consequently, whenever the second blocking lever 46 is rotated about the pin 44 in the clockwise direction, the first blocking lever 45 is compelled to rotate in the same direction.

Furthermore, when the first blocking lever 45 is rotated about the pin 44 in the clockwise direction, the spring 47 provides the biasing force by which the second blocking lever 46 will also be rotated in the clockwise direction, and under these conditions, should the second blocking lever 46 be compelled to maintain its position, only the first blocking lever 45 will be displaced while the spring 47 will be bent. The blocking rod 42 and a locking rod 48 are pivotally mounted upon lever 46 through means of a pin 49, the locking rod 48 being mechanically connected to a locking button, not shown. In FIG. 6, there is also disclosed a thrust washer 50 and a spring 51 which are provided so as to prevent the occurrence of clatter between the pin 49 and the second blocking lever 46, the locking rod 48, and the blocking rod 42.

The second blocking lever 46 also has an engaging portion 46b which extends below the pin 44 and which is positioned adjacent the elongated hole 25c within which the arm 30d of the interior opening lever 30 is displaceable when the door is in its open condition as shown in FIG. 7. Upon rotation of the second blocking lever 46 in the clockwise direction, the engaging portion 46b is shifted over across the aperture 25c so as to thereby limit the vertical displacement of the arm 30d, as may be more apparent upon reference to FIGS. 8 and 9. An L-shaped lever 53 is also pivotally provided upon the right side of the secondary base plate 25b by means of a pin 52 as seen in FIG. 6, lever 53 having two arms 53a and 53b. Arm 53a extends below the arm 30d of the interior opening lever 30 so as to be engagable therewith while the other arm 53b is provided with a circular aperture 53c through which an interior opening handle, not shown, is connected to the arm 53b, all as shown in FIG. 7.

In operation, when the door is closed from the open condition, as shown in FIGS. 1, 3 and 7, the door lock body 12 associated with the door is moved toward the striker 11. Thus, the lower portion of the latch 14 defining the recess 14a will contact the striker 11 whereby the latch 14 will be rotated in the clockwise direction, such movement resulting in the engagement between the recess 14a and the striker 11. Simultaneously, the first tooth 14b of the latch 14 causes the first pawl 16 to rotate in the counterclockwise direction and thereafter the first tooth 14b will engage with the engaging portion 16a of the first pawl 16 so as to establish the safety locking position of the door lock mechanism.

As a result of further rotation of the latch 14, the second tooth 14c thereof will engage with the engaging portion 16a of pawl 16 and the third tooth 14d will engage with the engaging portion 18a of the second pawl 18. Thus, the full locking posiion of the door lock mechanism, as shown in FIG. 2, is obtained. During this operation, the second pawl 18 is rotated about the axle 17 in the counterclockwise direction from the position shown in FIG. 1 and is, thereafter, returned to the position of FIG. 2. As a result of such movement, the head 45a of the first blocking lever 45 will be engaged with and repelled upwardly by means of the arm 18d of the second pawl 18, the first blocking lever 45 therefore being rotated about the pin 44 in the clockwise direction, as seen in FIG. 7, whereby the second blocking lever 46 is rotated by means of the biasing force of the spring 47 in the same direction.

This action results in the arm 46b of the second blocking lever 46 being displaced over the arm 30d of the interior opening lever 30, as shown in FIG. 8, and under these conditions, the door opening movement or force transmitted to the interior opening lever 30 through means of the interior lever 53 upon operation of the interior opening handle is limited by means of the arm 46b of the second blocking lever 46, the door opening operation through means of the interior opening handle thus being impossible. Concomitantly the locking rod 48 and the blocking rod 42 will be moved downwardly by means of the clockwise rotation of the second blocking lever 46, as seen in FIGS. 3 and 7, and such action causes the locking stopper plate 36 to rotate about the pin 37 in the counter-clockwise direction as seen in FIG. 3 whereupon the pin 39 now becomes engaged with the concaved portion 40b of the spring 40.

The movement range of the first blocking lever 45, due to the movement of the arm 18d, is designed and arranged by the suitable selection of the lever ratio of the corresponding parts such that it is sufficient for the pin 39 upon the locking stopper plate 36 to disengage from the concaved portion 40d and engage with the concaved portion 40b. In addition, a gap is provided between the locking plate 35 and the transmitting member 36b of the locking stopper plate 36, as will be apparent from FIG. 3, so that the movement of the locking stopper plate 36 is not transmitted to the locking plate 35.

As will be clear from the description noted hereinbefore, each part of the door lock mechanism will be displaced from the positions shown in FIGS. 1, 3 and 7 to the positions shown in FIGS. 2, 8 and 10 when the door is closed. In FIG. 10, the transmitting portion 36b of the locking stopper plate 36 will be substantially in contact with the locking plate 35, and at such time, the locking plate 35 is maintained at its position, as shown in FIG. 10, by means of the biasing force of the spring 38.

The door opening operation attained by means of movement of the interior opening handle from the above-mentioned condition is limited by the contact between the arm 30d of the interior opening lever 30 and the engaging portion 46b of the second blocking lever 46, as seen in FIG. 8, the interior lever 53 being prevented from rotating in the clockwise direction. When the exterior opening handle is displaced in the door opening direction, however, the exterior opening rod 34 is moved downwardly as seen in FIG. 10, so that the exterior opening lever 31 is rotated about the axle 17 in the clockwise direction through means of the pin 33. The pin 22 disposed within the hole 31a and rigidly mounted upon the second pawl 18 is also displaced about axle 17 in the clockwise direction whereby the engaging portion 18a of the second pawl 18 is disengaged from the third tooth 14d of the latch 14.

Simultaneously therewith, the pin 33 is displaced within the elongated hole 30c of the interior opening lever 30 without displacing the interior opening lever 30 and the opening link 28 is thus guided and moved downwardly through interengagement between the elongated hole 28c and the head 35a of the locking plate 35. As a result of such downward movement, the first engaging portion 28a of link 28 will engage with the head 26b of the arm 26a of the opening lift lever 26 so that the latter is rotated about the axle 15 in the clockwise direction. The pin 21, which is rigidly mounted upon the opening lift lever 26, is also rotated about axle 15 in the same direction, and consequently, the first pawl 16 is rotated about the axle 15 in the counter clockwise direction, as seen in FIG. 2, so as to disengage the engaging portion 16a of the first pawl 16 from the second tooth 14c of the latch 14.

As will be clear from the description hereinbefore noted, the door opening operation of the exterior opening handle will simultaneously release the engagements between the first pawl 16 and the latch 14, as well as between the second pawl 18 and the latch 14, however the door opening operation of the interior opening handle will not release the above-mentioned engagements, thus providing "child-proof conditions." In addition, the second pawl 18 engages with the third tooth 14d of the latch only when the door is fully closed. In other words, the second pawl 18 does not engage with the third tooth 14d when the first pawl 16 engages with the first tooth 14b, namely, when the door lock mechanism is in its safety locking position. THerefore, the door can be openedj by either of the door opening operations by means of the interior or exterior opening handles under such safety locking conditions.

The door locking operations from the exterior or interior positions of the vehicle will now be explained. In order to lock the door from the conditions shown in FIGS. 3 or 10, the key rod 43 may be moved upwardly, as shown in FIG. 11, by means of the key operation from the exterior of the vehicle. As a result of such key operation, the locking stopper plate 36 is rotated counterclockwise, as shown in FIG. 11, and the pin 39 now engages with the concaved portion 40c of the spring 40. Alternatively, the locking rod 48 may be moved downwardly by means of the locking button from the interior of the vehicle whereby the locking stopper plate 36 may be similarly rotated or displaced through means of the pin 49 and the blocking rod 42 to the position shown in FIG. 11.

As a result of either operation, the transmitting portion 36b of the locking stopper plate 36 causes the locking plate 35 to rotate counter-clockwise about the pin 37. At such time after the locking plate 35 has rotated beyond the neutral point of the turn-over spring 38 from the position of the locking plate 35 shown in FIG. 10, the locking plate 35 is biased and rotated by means of the biasing force of the spring 38. The opening link 28 is thus displaced through means of the head 35a of the locking plate 35 to a position at which the second engaging portion 28b of the opening link 28 is engaged with and stopped by means of the head 26d of the arm 26c of the opening lift lever 26, as shown in FIG. 11.

Under these conditions, the downward movement of the opening link 28 through the exterior opening handle and the exterior opening rod 34 will not come into contact with the head 26b of the opening left lever 26. The operation of the exterior opening handle will thus result in only idle movements of the exterior opening rod 34 and the opening link 28 so that the door cannot be opened.

While the downward movement of the locking rod 48 causes the second blocking lever 46 to rotate about the pin 44 in the clockwise direction in FIG. 7, the first blocking lever 45 will also rotate in the same direction because of the engagement between the engaging portion 46a of the second blocking lever 46 and the upper edge of the arm 45b of the first blocking lever 45. More particularly, the second blocking lever 46 is displaced from the position of FIG. 8 to the position shown in FIG. 9, at which the arm 46b of the second blocking lever 46 is moved or displaced so as to be over the arm 30d of the interior opening lever 30. The door opening movement of Therefore, interior opening lever 30 opened from the interior opening handle to the inside lever is thus limited by means of the arm 46b so that the door cannot be opened.

When each part of the door lock mechanism is in the locking position, as shown in FIG. 11, the door opening movement of the interior opening handle will be limited while the door opening movement of the exterior opening handle will be idled, and accordingly, the door cannot be opened by either of the door opening operations initiated by either of the interior or exterior handles. In order to release this door locking condition the key rod 43 may be pushed downwardly by means of the vehicle door key from a position exterior of the vehicle, or alternatively the locking rod 48 may be raised up by means of lifting the locking button from a position interiorly of the vehicle. In consequence, the locking plate 35 and the locking stopper plate 36 may be returned to their respective positions as shown in FIG. 3 and the first and second blocking levers 45 and 46 may be returned to their respective positions, as shown in FIG. 7.

The cancelling or unlocking operation, that is, the operation whereupon the door is closed and not capable of being opened from the inside although openable from the outside, of the door lock mechanism will not be explained. It will be recalled that during the closing movement of the door, the first pawl 16 is rotated about the axle 15 in the counter-clockwise direction, as seen in FIG. 1, by means of engagement between the first tooth 14b of the latch 14 and the tooth 16a of the pawl 16, and thus the pin 21 is rotated about the axle 15 in the same direction. This results in the clockwise rotation of the opening lift lever 26 as seen in FIG. 11 whereupon the head 26d of the arm 26c of the opening lift lever 26 will engage with the second engaging portion 28b of the opening link 28 so that the latter is rotated about the pin 33 in the counter-clockwise direction.

The movement of the opening link 28 is of course transmitted to the locking plate 35 through means of the head 35a of the locking plate 35 and the portion of link 28 defining slot 28c whereby the locking plate 35 is displaced to the position shown in FIG. 10. The locking stopper plate 36 is also displaced as a result of the engagement between the transmitting member 36b and the locking plate 35, to the position at which the pin 39 is engaged with the second concaved portion 40b of the spring 40 as seen in FIG. 10. The second pawl 18 will of course be maintained at its position as shown in FIG. 1 due to the fact that the latch 14 does not have any teeth which are engaged with the second pawl 18 in the safety locking position.

As a result of the further door closing movement, both of the first and second pawls are rotated by means of the latch 14 in the counter-clockwise directions as seen in FIG. 1, however rotation of the first pawl 16 merely causes the idle motion of the opening lift lever 26 through means of the pin 21 while rotation of the second pawl 18 merely causes the rotation of the pin 22 within the elongated holes 30b and 31a of the interior and exterior opening levers 30 and 31, both opening levers 30 and 31 being maintained at their positions as shown in FIG. 10. Thus, the cancelling operation will be obtained whereupon the "child-proof conditions" will exist whereupon the door can be opened by the operation of the exterior opening handle, although the door cannot be opened by the operation of the interior opening handle.

The keyless locking operation of the mechanism will now be explained. When the mechanism is in the door locking condition, each part of the mechanism is in its position as seen in FIG. 11, and the exterior opening rod 34 and the opening link 28 may be displaced downwardly by means of the door opening movement of the exterior opening handle. Under these conditions however, when the door is closed and the latch 14 is moved by means of the striker 11 to the fully locked position, as shown in FIG. 2, displacement of the first and second pawls 16 and 18 merely cause idle movements of the pin 21, the opening lift lever 26, and the pin 22, and the head 26d of the arm 26c of the opening left lever 26 will not engage with the second engaging portion 28b of the opening link 28. The door can be closed without the displacement of the locking plate 35 and thus the keyless locking operation will be obtained. Thereafter, the door opening movement of the exterior opening handle results in only the idle motions of the outside opening rod 34 and the opening link 28 and the door cannot be opened.

Referring now to FIGS. 12-14, another embodiment constructed according to the present invention is disclosed wherein the first blocking lever 45 is disposed upon the second blocking lever 46 and both of the blocking levers 45 and 46 are pivotally mounted, by means of the pin 44, upon the secondary base plate 25b. The spring 47 interposed between the levers 45 and 46 biases the first blocking lever 45 in the counter-clockwise direction and biases the second blocking lever 46 in the clockwise direction. As a result of such biasing forces, both of the levers 45 and 46 are normally maintained at their illustrated positions, as seen in FIG. 12, at which the right arm 45b of the first blocking lever 45 engages the stopper portion 46a of the second blocking lever 46.

The lower arm 46b of the second blocking lever 46 is formed with a arcuate-shaped elongated hole 46c the center of which is located at the pivot pin 52 associated with the inside opening lever 53. The opening lever 30 includes the arm 30d the end portion of which is flanged so as to extend vertically and an arm 30e which extends parallel to the lower portion of the arm 46b. The arm 30e is provided with an arcuate-shaped elongated hole 30f the center of which is located at the pin 44 pivotally supporting the first and second blocking levers 45 and 46. The right end portion of the aperture 30f and the lower end portion of the aperture 46c are normally overlapped when the door is opened, and under these conditions, the pin 55 is slidably disposed within both of the apertures 30f and 46c, pin 55 being adapted to engage with the arm 53a of the interior lever 53 when each part is in the illustrated position shown in FIG. 12.

The normal door opening condition in which the interior and exterior opening handles are in their non-operated positions or a door closing condition in which the lock mechanism is released by means of the locking button or the key is shown in FIG. 12, and from such conditions, when the interior opening handle is operated, the interior lever 53 is rotated from its position shown in solid line to the position shown by the chain-line in FIG. 12, whereby the arm 30e of the interior opening lever 30 is displaced upwardly due to the fact that the pin 55 is located within the rotational locus of the arm 53a. The interior opening lever 30 is thus rotated about the axle 17 in the clockwise direction, as well as the pin 22 and the opening link 28 being moved accordingly, such movements resulting in the rotation of the first and second pawls 16 and 18, whereupon the door can now be opened. At this time, the second blocking lever 46 is maintained at the position illustrated in FIG. 12 while the first blocking lever 45 is rotated about the pin 44 in the clockwise direction by means of the arm 18d of the second pawl 18, the movement of the first blocking lever 45 being permitted by means of the spring 47 whereby the second blocking lever 46 is not forced to be rotated therewith.

When the door is closed from the open door condition as shown in FIG. 12, the second pawl 18 is rotated about the axle 17 so that the arm 18d of the second pawl 18 is displaced upwardly as seen in FIG. 12. Therefore, the first blocking lever 45 is rotated about the pin 44 in the clockwise direction and the second blocking lever 46 is similarly rotated by means of the spring 47. The pin 55, which is slidably disposed within the aperture 46c of the second blocking lever 46 is now moved toward the left within the aperture 30f to the position shown in FIG. 13. This motion is transmitted to the blocking rod 42 and the locking stopper plate 36 through means of pin 49, such component parts being maintained at their positions illustrated in FIG. 13 by means of the engagement between the pin 39 and the spring 40.

At this time, the operation of the interior opening handle merely causes idle movement of the interior lever 53, that is, arm 53a will not be able to engage the pin 55. Thus, the interior opening lever 30 will not be moved and the child-proof condition will be obtained. The second blocking lever 46 is of course able to be displaced by means of the locking operation of the key or locking button into the position shown in FIG. 14 whereupon the pin 55 is moved toward the left within the aperture 30f, and consequently, the operation of the interior opening handle merely causes idle movement of the interior lever 53 all in the same manner as discussed heretofore in connection with the components illustrated in FIG. 13.

Obviously many modifications and variations of the present invention are possible in light of the above teachings. It is to be understood therefore that within the scope of the appended claims the invention may be practiced otherwise than as specifically described herein.

Claims

What is claimed as new and desired to be secured by Letters Patent of the United States is:

1. A door lock mechanism comprising:

a rotatable latch engageable with a striker;

a first pawl engageable with said latch for maintaining said latch in a locking position and biased by a first biasing means in one direction;

means in said lock mechanism responsive to the rotational movement of said latch when the door is closed;

an exterior door opening means for releasing said engagement between said first pawl and said latch;

an interior door opening means for releasing said engagement between said first pawl and said latch; and

means for preventing and limiting only said door opening operation of said interior door opening means in response to said means responsive to the rotational movement of said latch.

2. A door lock mechanism as set forth in claim 1, wherein:

said means responsive to said rotational movement of said latch is a second pawl which engages with said latch in said locking position; and

said door lock mechanism further comprises connecting means for connecting said interior and exterior door opening means for simultaneously disengaging both of said pawls from said latch upon operation of either one of said exterior and interior door opening means.

3. A door lock mechanism comprising:

a rotatable latch engageable with a striker;

first pawl means engageable with said latch for maintaining said latch at its full locking position and biased by a first biasing means in one direction;

second pawl means engageable with said latch for maintaining said latch at said full locking position and biased by a second biasing means in said one direction;

first connecting means including an exterior door opening means for releasing said engagement between said first pawl means and said latch;

second connecting means including an interior door opening means for releasing said engagement between said second pawl means and said latch;

third connecting means for connecting said first and second connecting means for simultaneously disengaging both of said first and second pawl means from said latch upon operation of either one of said exterior and interior door opening means;

said third connecting means comprising a first idle means which does not transmit the movement of said pawl means to said interior and exterior door opening means when said pawl means are engaged with said latch;

locking means associated with said first connecting means for displacing said first connecting means to an uncoupled position at which the door opening movement of said exterior door opening means is not transmitted to said first pawl means, or to a coupled position at which the door opening movement of said exterior door opening means is transmitted to said first pawl means;

a child-proof means associated with the rotation of said second pawl means for displacing said interior door opening means to an inoperative position in which the door opening movement of said interior door opening means is not transmitted to said pawl means;

fourth connecting means for connecting said locking means and said child proof means, said locking means comprising a second idle means which maintains said first connecting means at said coupled position when the movement of said second pawl means is transmitted to said locking means through said child-proof means and said fourth connecting means; and

fifth and sixth connecting means for displacing said locking means in its locking position to thereby displace said first and second connecting means to the uncoupled and the inoperative positions, respectively.

4. A door lock mechanism as set forth in claim 3, wherein said first connecting means comprises an opening lift lever which is adapted to be moved in conjunction with said first pawl means, whereby the movement of said opening lift lever with said locking means in its locking position is adapted to displace said locking means in its unlocking position when said first connecting means is in its inoperative position.

5. A door lock mechanism as set forth in claim 4, wherein said movement of said opening lift lever is adapted to be idled when said first connecting means is in its operative position.

6. A door lock mechanism as set forth in claim 3, wherein said child-proof means comprises:

blocking lever means displaced by the rotation of said second pawl means to thereby limit the door opening movement of said interior door opening means.

7. A door lock mechanism as set forth in claim 3, wherein said child-proof means comprises:

blocking lever means displaced by the rotation of said second pawl means and pin means associated with the displacement of said blocking lever and movable between a first position in which the door opening movement of said interior door opening means is transmitted to said third connecting means and a second position in which the door opening movement of said interior door opening means is idled.