Inventors:
Kleefeld, Frank (Heiligenhaus, DT)
Gmeiner, Gunter (Sindelfingen, DT)
Assignee:
Arn, Kiekert Sohne (Heiligenhaus, DT)
Daimler-Benz Aktiengesellschaft (Stuttgart-Unterturkheim, DT)
Field of Search:
292/216,280,DIG.38,DIG.26 70/464
Claims:
We claim
1. A door latch comprising;
2. The latch defined in claim 1 wherein said locking means includes mechanism having a pivot on said housing for displacing said arm.
3. The latch defined in claim 2 wherein said actuating member is a lever having a pivot on said housing independent of said pivot of said mechanism.
4. The latch defined in claim 1 wherein said pin has a low-friction surface composed of polytetrafluorethylene.
Description:
FIELD OF THE INVENTION
The present invention relates to a latch and, more particularly to a lockable motor-vehicle door latch.
BACKGROUND OF THE INVENTION
In a conventional motor-vehicle door latch a coupling body on the doorpost is engageable with a locking pawl carried on the door edge. An operating lever or other similar element cooperating with such a lever is formed as a keeper and is engageable with the locking pawl to prevent its displacement unless the inner or outer door handle is operated. As a general rule an actuating lever or member is provided which is directly coupled to the two door handles, and a link is provided between this member and the keeper lever. A locking mechanism can act on this link to decouple the keeper from the door handles so that the door is locked. The link is usually a bent-over tab projecting from one of the levers, and one of the levers has a pivot displaceable by the locking mechanism into a position wherein the tab does not grasp the other lever. This, of course, ensures that the handles will be ineffective until the movable lever is displaced back to its position in which the tab is effective.
With such locks, displacement of the actuating member with the locking mechanism in an actuated state brings the various elements out of line with each other so that, even if the locking mechanism is operated to unlock the door, the handle must be released and then actuated again to open the door. This is often a bother when a person trying to open the door for another operates the outer handle before the person inside has unlocked the door. More important, in cases in which an accident has occurred is it often the situation that the inner or outer door handle is jammed in the actuated position (pressed in or drawn out) so that, with the door locked, it is impossible to open the door. For instance should something become wedged under the outer door handle while the door is locked, the passenger cannot unlock the door from the inside since even if the locking mechanism is operated, the outer handle has to be returned to its unactuated position before the various elements of the mechanism allow the handles to function to open the door. A similar problem faces the rescuer.
OBJECTS OF THE INVENTION
It is therefore an object of the present invention to provide an improved door latch of economical construction and reliable operation effectual to permit in a vehicle lock construction of the character described, convenient escape of a passenger should an accident befall the vehicle.
Another object is the provision of a motor-vehicle door latch which overcomes the aforementioned disadvantages.
SUMMARY OF THE INVENTION
These objects are attained according to the present invention in a latch wherein the actuating member (that element which is operated directly by the door handles and can even be a guide on the operating lever, which is that element that blocks or unblocks the locking pawl. The link is displaceable along one of the guides between two locations, in the first of which it couples the actuating member to the operating lever, and in the second of which it permits displacement of the actuating member without displacement of the operating lever. This second position corresponds to the locked position of the door. Locking mechanism is provided for displacing this link back to the first-described position when the actuating member is in the actuated position so as to engage this link against the other guide and cam the operating lever over and free the pawl. Thus if one of the door handles is for some reason retained in the actuated position with the locking mechanism in the locked position, simple operation of the locking mechanism will unlock and open the door.
According to another feature of this invention the locking mechanism is formed of a chain of levers pivoted on the latch housing, one of the levers having an arm carrying a pin which constitutes the link.
More specifically, the link is made of a synthetic resin having a low coefficient of friction polytetraflourethylene (Teflon) being found advantageous, and rides in a groove or slot on the actuating member and is engageable with a guide surface on the operating lever.
DESCRIPTION OF THE DRAWING
The above and other objects, features and advantages will become apparent from the following with reference to the accompanying drawing in which:
FIG. 1 is a perspective view of the latch according to the present invention;
FIG. 2 is a perspective view of the latch seen in the direction of arrow II of FIG. 1; and
FIGS. 3 and 4 are diagrammatic views illustrating operation of the latch in the unlocked and locked positions, respectively.
SPECIFIC DESCRIPTION
As shown in FIGS. 1 and 2 the latch comprises an L-shaped housing 2 adapted to be mounted at the edge of a motor vehicle door with its longer side 2' extending tangentially of the door's pivot axis and its shorter side 2" lying in a plane parallel to the plane of the door. A coupling element 3 is engageable in a cutout 4 formed in the housing 2. This heavy steel element 3 is secured to the vehicle doorpost. A second steel plate 36 is riveted to the inside of housing 2 to close the inside of cutout 4.
Provided within the cutout 4 is an outwardly directed pin 19 having a frustoconical end 19' receivable within a correspondingly shaped socket or hole 20 in the coupling element 3 which is formed with a pair of ledges 21 which engage under the edges of cutout 4 to secure the element 3 tightly within the housing 2 and insure an exact positioning of the door relative to the doorpost in the closed position of the door.
The element 3 is provided between its ledge 21 and main body with two parallel steel pins 5 which coact with teeth 22 of a locking pawl 1 pivoted at 23 on the housing side 2' and the plate 36 below the cutout 4. The pawl 1 is shown in FIG. 1 in solid lines in the position it assumes with the door closed and in dot-dash lines in the door-open position. The pins 5 act as the teeth of a rack which mesh with the teeth 22 of the pawl 1.
This pawl 1, as shown in FIG. 2, is normally biased by a spring 24 into the dot-dash line position of FIG. 1, but can be stepped in either the solid-line position of FIG. 1 or an angular position intermediate the two by engagement of an element 6 with either of two teeth 25 formed on the pawl. The element 6 is a two-arm lever pivoted at 7 on the side 2' and having an arm 9 by which it is operated and an arm 26 having an end 27 acting as a keeper and engageable with the teeth 25 to block the pawl 1. A spring 28 is provided to urge the end 27 against the pawl 1.
The door is opened by actuation of an inside or outside door handle 29 which pivots a lever 8 about its axis 30 on the side 2' in the direction shown by arrow 14. This is shown in FIG. 3 where a coupling bolt 15 of polytetrafluorethylene is shown engaged in a slot 16 formed in the lever 8. Displacement of the lever in direction 14 pushes the bolt 15 against the actuating arm 9 of the operating element 6 to pivot this element back and free the pawl. In FIG. 3 the actuated position is shown in solid lines and the unactuated position in dot-dash lines.
A locking lever 11 is pivoted at 10 on the side 2" of the housing 2. When a locking button 31 on the vehicle door is depressed or when a lock cylinder 32 is rotated this element 11 pivots a lever 12 pivoted on the housing 2 on a pin 37 at the base of the cutout 4 in the direction by arrows 13. Another element 33 is pivoted on this lever 12 and engageable with the pawl 1 to prevent the vehicle door from being shut with the button 31 depressed so as to make it impossible for the operator to lock his keys in the car. Pivotal on a pin 34 on the end of lever 12 is an operating arm 35 on whose end the Teflon pin 15 is mounted.
When the button 31 is depressed or the lock cylinder 32 rotated with the door closed the lever 11 will pivot to slide the pin 15 down in the slot 16 toward the axis 30. FIG. 3 makes it clear that if the pin 15 is in this position pivoting of the lever 8 from the dot-dash position to the solid-line position will not operate the arm 9 of lever 6 since the pin 15 will not couple the two together. The pin 15 will not engage this arm 9 at all.
Should for some reason the door handle outside the car be actuated or the handle inside the car be similarly actuated with the door locked so that a person on the other side of the door is unable to open the door from his side, all that person need do is operate his unlocking mechanism 31 or 32. This unlocking will pivot the lever 12 to slide the pin 15 up in the slot 16. As shown in FIG. 4, when the unlocking lever 8 is in the actuated, solid-line position and the pin 15 is down in the locked position, operation of the locking mechanism will slide this pin 15 up in the direction of arrow 18 along the curved inside surface 17 of the operating arm 9 to force the lever 6 back and free the pawl 1. Thus in an accident or the like the door can be opened, even though locked, from the inside or outside even though the handle on the other side is for some reason blocked in the actuated position.