Door latch device for vehicles

Abstract

A door latch device includes a latching mechanism, an outer lever operatively connected to the latching mechanism, a locking lever operable by the locking push button to control the operation of the outer lever, a L-shaped lever normally connected to the outer lever, a pin mounted on the L-shaped lever, an inner lever operable by the inside door handle to transmit the door opening force to the outer lever through the pin and the L-shaped lever, and a "childproof" locking lever to move the pin in the "childproof" locking position wherein the inner lever is out of engagement of the pin and in the "childproof" unlocking position wherein the inner lever is engageable with the pin. Thus, an accidental opening of the door may be prevented by such a "childproof" operation of the "childproof" locking lever.

Description

BACKGROUND OF THE INVENTION

The present invention generally relates to a door latch device for the vehicle, and more particularly to a door latch device including a "childproof" locking mechanism which will prevent an accidental opening of the door of automotive vehicles.

It is well known in a door latch device for the automotive vehicle that when an inside lock button is usually pushed, an inside door handle for opening the vehicle door is made unactuated to thereby keep the door closed. That is to say, the door can not be opened as far as the locking button is being pushed. But, if the pushed condition of locking button is accidentally released, e.g., the push button happens to be lifted up by a child sitting on the rear seat of automotive vehicle the door can be opened by operation of the inside door handle. When such happenings are occurred during driving of the vehicle, there is a danger for passengers of being thrown out of the vehicle.

In order to obviate such a drawback, there has been proposed a door latch device having a "childproof" locking mechanism. According to this mechanism, the operation of door handle does not cause the door to be opened even when the locking of door latch device is released by accidental lifting of the locking button.

However, the conventional "childproof" mechanism still has a difficulty that when a considerable force is applied to the inside door handle the "childproof" mechanism is likely to be damaged due to the said force. The damage of "childproof" mechanism will result in ineffectiveness thereof, so that the safety of passengers is still in question.

SUMMARY OF THE INVENTION

Accordingly, one of the objects of this invention is to provide a door latch device for vehicle which is more improved in safety than the conventional door latch device by obviating the conventional drawback.

Another object of this invention is to provide a door latch device for vehicle wherein when a considerable force is applied to the door handle so as to open the door, the said force result in idle movement, as for as a "childproof" lever is positioned in its locked position.

A further object of this invention is to provide a door latch device for vehicle which is simple in structure and inexpensive in manufacture.

The other objects and advantages of this invention will be apparent from the following description of the preferred embodiment of this invention taken in connection with the appended drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is a front view of a door latch device according to the present invention in its door unlocked position;

FIG. 2 is a right side view of the door latch device of FIG. 1 wherein a "childproof" locking mechanism is in its unlocked postion;

FIG. 3 is a rear view of the door latch device in its door latched postion;

FIG. 4 is a sectional view of the door latch device taken along the line IV--IV of FIG. 1 or the line IV'--IV' of FIG. 3;

FIG. 5 is a sectional view of the door latch device taken along the line V--V of FIG. 2; and

FIG. 6 is a view similar to FIG. 2, but showing the "childproof" locking mechanism in its locked position.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to the drawings, especially FIGS. 1-4 thereof, a door latch body 10 made of synthetic resin is fixed to the vehicle door (not shown) by bolts 11. The body 10 includes an inner base plate 12 and an outer base plate 13 fixed to each other by screw means 14. Whithin the latch body 10 is mounted a fork-shaped latch member 15 made of metal and having its integral latch axis 16 pivotally mounted on the inner and outer base plates 12 and 13. The latch member 15 is normally urged to rotate in clockwise direction (FIG. 3) around the latch axis 16 by a coiled spring 17. A pawl 18 also made of metal is rotatably mounted on a pin 19 through the body 10 and is urged to rotate in the counter-clockwise direction (FIG. 3) by a coil spring 20 thereby to allow a tooth 21 of the pawl 18 to engage a tooth 22 of the latch member 15 as shown in FIG. 3.

A pin 23 is fixed to the pawl 18 at its one end and is fixed to a lift lever 24 at its other end which lever is in turn pivotally mounted on the pin 19. An outer lever 25 is also pivotally mounted on the pin 19 and urged to rotate in the counter-clockwise direction (FIG. 1) by a coiled spring 26 interposed between the outer lever 25 and the lift lever 24 (FIG. 4). The outer lever 25 is provided with an elongated slot 27 and an edge portion 28.

A locking lever 29 is rotatably mounted on a pin 30 fixed to the outer base plate 13 against the exerting force of a coil spring 31 and mechanically connected to a link member 32. The locking lever 29 is connected to an inside lock button (not shown). The link member 32 is in turn operatively connected to the outer lever 25 through a pin 33 secured to the end portion thereof and slidably fitted within the elongated slot 27 of the outer lever 25. The pin 33 is capable of engaging the lift lever 24 when in a position of FIG. 1, that is to say, in the door latch unlocking position.

A first and a second inner levers 34 and 35 are coaxially mounted on a shaft 36 which is fixed to the outer base plate 13. The first inner plate 34 formed into an inverted L-shape is provided at its one end with a fork end 37 with which the edge portion 28 of the outer lever 25 is engaged, and, at its other end with an elongated slot 38. The second inner plate 35 is urged to rotate in the clockwise direction (FIG. 2) by a coil spring 39 mounted on the shaft 36 and is provided with an edge surface 40. The second inner lever 35 is mechanically connected to an inside door handle (not shown) which is operated when the door is to open.

A pin 41 is fitted slidably along the elongated slot 38 of the first inner lever 34 and is engageable with the edge surface 40 of the second inner lever 35 as is shown in FIG. 5.

A "childproof" lever 42 of the "childproof" locking mechanism is pivotally mounted on a rivet 43 secured to the outer base plate 13 and is provided with an elongated slot 44. The outer base plate 13 is also provided with an elongated slot 45. Therefore, the pin 41 is movable also within the elongated slots 44 and 45 of "childproof" lever 42 and outer base plate 13 as best shown in FIG. 5. A coiled spring 46 is interposed between the outer base plate 13 and the "childproof" lever 42 to thereby urge the "childproof" lever 42 to rotate around the rivet 43 in the clockwise direction (FIG. 2).

In operation, when the door is opened from the door closed position of FIG. 3, the second inner lever 35 is rotated in the counter-clockwise direction (FIG. 2) by the inside door handle to thereby engage the edge surface 40 with the pin 41. Thus, the first inner lever 34 is also rotated in the counter-clockwise direction (FIG. 2) around the shaft 36 to thereby transmit the rotational force of the first inner lever 34 to the outer lever 25 through connection between the fork end 37 and the edge portion 28. The outer lever 25 is, therefore, rotated in the counter-clockwise direction (FIG. 1) around the pin 19 so as to permit engagement of the pin 33 with the lift lever 24. The rotation of the lift lever 24 around the pin 19 causes the rotation of the pawl 18 in the clockwise direction (FIG. 3) due to connection between the lift lever 24 and the pawl 18 via pin 23. Thus, engagement of the tooth 21 of pawl 18 with the tooth 22 of latch member 15 is released and the latch member 15 is rotated in the clockwise direction (FIG. 3) by the spring 17, so that the door is in the opened position.

When the door latch device is to be locked from the door latch unlocked position of FIG. 1, the locking lever 29 is rotated in the counter-clockwise direction around pin 30 (FIG. 2) by the inside lock button. The link 32 is thus lifted up (FIG. 1) to thereby bring the pin 33 fixed to the link 32 into the unengaged position wherein the pin 33 is not capable of engaging the lift lever 24 even if the outer lever 25 is moved to rotate by the inside door handle. Accordingly the door is brought in the locked position.

Referring now to the "childproof" locking operation, the "childproof" lever 42 is in the unlocked position in FIG. 2. When the "childproof" lever 42 is rotated in the counter-clockwise direction against the spring 46 around the rivet 43, the pin 41 is lowered slidably along the elongated slot 38 to the position of FIG. 6. That is, the side edge of the elongated slot 44 forces the pin 41 to move downward. Therefore, even when the second inner lever 35 is moved to rotate by the inside handle, the edge surface 40 of the second inner lever 35 is not capable of engaging the pin 41, and so the first inner lever 34 is kept in the position illustrated in FIG. 6 to thereby keep the door latch locked position because no force is applied to the outer lever 25, the lift lever 24, and the pawl 18. The rotation of the second inner lever 35 results in idle movement without any engagement with the other members, as far as the "childproof" lever 42 is positioned in its locked position. Accordingly, there is no fear of damage of the various members when a considerable force is accidentaly applied to the second inner lever 35.

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 present invention may be practiced otherwise than as specifically described herein.

Claims

We claim:

1. A door latch device for a vehicle comprising in combination:

a latch body;

a latch member rotatably mounted on said latch body;

a pawl rotatably mounted on said latch body and engageable with said latch member;

an outer lever operatively connected to said pawl and movable for controlling the rotation thereof;

a locking lever mechanically connected to said outer lever for controlling the movement of said outer lever;

a first inner lever rotatably mounted on said latch body and mechanically connected to said outer lever for unitary movement therewith, said first inner lever being provided with an elongated slot;

a pin slidably fitted within said elongated slot and movable along said elongated slot;

a second inner lever pivotally mounted on said latch body and operatively connected to said pin; and

a "childproof" lever pivotally mounted on said latch body and operatively connected to said pin, said "childproof" lever being movable to an unlocked position wherein said second inner lever is engageable with said pin and to a locked position wherein said second inner lever is out of engagement with said pin.

2. A door latch device of claim 1, wherein said "childproof" lever is provided with an elongated slot, said pin is moved by engagement with said elongated slot of "childproof" lever.

3. A door latch device of claim 1, wherein said second inner lever includes an edge surface with which said pin is engageable when said "childproof" lever is in its unlocked position.

4. A door latch device of claim 3, wherein said first inner lever includes a forked end, said outer lever includes an edge portion normally engaged with said forked end for unitary movement therewith.

5. A door latch device of claim 1, wherein a link is provided between said locking lever and said outer lever so as to transmit the movement of said locking lever to said outer lever.

6. A door latch device of claim 5, wherein pin means is secured to one end of said link, said outer lever is provided with an elongated slot within which said pin means is slidably fitted.

7. A door latch device of claim 6, further comprising a lift lever rotatably mounted on said latch body, said lift lever being engageable with said pin means.

8. A door latch device of claim 7, wherein said lift lever includes a through pin secured to said pawl whereby a rotation of said outer lever causes a rotation of said pawl through said lift lever when said pin means is engageable with said lift lever.

9. A door latch device of claim 8, wherein said pawl, lift lever, and outer lever are mounted on said latch body coaxially with each other.

10. A door latch device of claim 1, wherein said second inner lever is movable from inside of the vehicle and mounted coaxially with said first inner lever.