EP0721538B1

EP0721538B1 - Liftgate latch

Info

Publication number: EP0721538B1
Application number: EP94928664A
Authority: EP
Inventors: Nigel Spurr
Original assignee: Rockwell International Corp
Current assignee: Boeing North American Inc
Priority date: 1993-09-30
Filing date: 1994-09-26
Publication date: 2001-05-23
Anticipated expiration: 2014-09-26
Also published as: EP0721538A1; DE69427302T2; DE69427302D1; WO1995009289A1

Description

This invention relates to latches for securing the position of a door according to the preamble of claim 1.

A typical vehicle door includes a latch which defines three modes of operation. A first mode is a latched mode in which a striker forkbolt is engaged to a striker. A second mode of operation is an open mode of operation in which the striker forkbolt and striker are released and function independently to provide access to a vehicle. A third mode of operation is one in which the striker forkbolt and striker are partially engaged allowing limited motion of a door which has been partially closed or which has been released incompletely from a latched condition to a mode of operation referred to as safety or secondary mode. The sequence of opening a vehicle door in which the door is rotatable about a horizontally oriented axis such as a deck lid includes a first step of releasing the vehicle door from a latched mode of operation, whereupon a weatherstrip imparts a force against the door causing an upwardly directing motion thereof. Upon reaching the limit of such displacement, the door returns to a position resting against the weatherstrip, and in some situations, engaging the striker forkbolt and striker sufficiently to reach a safety mode of operation. A vehicle operator inside such a vehicle attempting to open the door will find the door in a safety mode of operation, and consequently impossible to open.

GB-A-2 155 535 discloses a latch according to the preamble of claim 1 for a vehicle door which offers a sequence of operations in which the door is first released from a latched condition to an ajar condition in which no safety mode of operation is available. Subsequent to the ajar condition the vehicle door may then pass to an open position in which the safety mode of operation is reset and may be utilized upon subsequent attempts to close the door. The latch comprises several levers which may contact each other to swivel latches in order to change the mode of operation.

From their swivelled position the levers have to pivot back in their initial position due to the force of gravity. If. the door is, however, slammed, it has the tendency to spring back in an open position. The levers, however, are due to their inertia mass not able to lock the door in a latched condition so that the door is allowed to rebound in the open position. Therefore, the door equipped with the known latch must always be closed slowly.

Object of the present invention is to provide for a latch which ensures a safe closure of the door.

This object is achieved by the features of claim 1.

The present invention includes a device which establishes a sequence for the modes of operation of a door. The sequence is latched, ajar, open and safety. The modes of operation are achieved by the interaction of a striker and a striker forkbolt. The striker forkbolt is secured to the liftgate and the striker is secured to the fixed structure. The striker forkbolt is rotatable about a first axis to various predetermined angular positions. The striker forkbolt may be restricted to various rotational positions to accomplish one of the four modes of operation. A first angular restriction of the striker forkbolt in which the striker forkbolt is engaged with a striker defines the latched mode of operation. A second angular restriction allows unrestricted rotation of the striker catch between the first limit of rotation and a maximum limit of rotation in which the striker forkbolt and the striker may be disengaged upon application of a force attempting to displace the liftgate to an ajar position. A third range of angular positions of the striker catch occurs upon rotation of the striker forkbolt to the maximum limit of rotation whereupon the striker forkbolt and the striker are completely disengaged permitting the door to be positioned in an open mode of operation. The fourth range of angular positions occurs in which the striker forkbolt is restricted to a second limit of rotation in which the striker forkbolt engages the striker defining a safety mode of operation. The invention includes a pawl which is selectively rotatable about a second axis and may be engaged with cooperating abutment surfaces defined on the striker forkbolt to provide various rotational restrictions thereof. The pawl is maintained in a first position engaging a first radially extending abutment surface to define the latched condition. The pawl is maintained in a second angularly displaced position which prevents the pawl from engaging the striker forkbolt to define an ajar mode of operation in which the striker forkbolt is free to rotate from the latched condition to a maximum limit of rotation. The pawl is maintained in a third condition in which the pawl is compliantly urged into contact with the rotatable striker forkbolt to define an open mode of operation. Finally, the pawl is maintained in a fourth condition engaged with a second cooperating radially extending abutment surface of the striker forkbolt to define a safety mode of operation. The preferred embodiment of the present invention includes a first rotatable member engaged with the pawl drivingly engaged to a second member. The second member may be selectively restricted in rotation by an engagement with a third member. Such a restriction of rotation of the second member thereby restricts rotation of the first member defining a displaced position of the pawl which permits the vehicle door to be operated in an ajar condition in which the door will not enter the safety mode of operation until it has been displaced into the position defined by the open mode of operation.

These and other details of the present invention will become more readily apparent by reference to the following detailed description of the embodiments as shown in the drawings.

Figure 1 is a perspective view of a structure including a door which is controlled by the apparatus of the present invention;

Figure 2 is a plan view of a first plane of the components of the present invention illustrating the latched mode of operation;

Figure 3 is a plan view of a first plane of the components of the present invention illustrating an ajar mode of operation;

Figure 4 is a plan view of the second plane of the components of the present invention illustrating the latched mode of operation;

Figure 5 is a plan view of the second plane of the components of the present invention illustrating the end of ajar mode of operation just before reaching the open position;

Figure 6 is an explosive view of the apparatus according to the present invention.

The present invention comprises an apparatus for establishing a mode of operation of a vehicle door 10 as shown in Figure 1, secured to the fixed structure of an automobile 14 having striker assembly 16 engageable with the apparatus of the present invention 18. The apparatus of the present invention is secured to the vehicle door 10 and is utilized to define and establish various modes of operation of vehicle door 10. The apparatus of the present invention constitutes an assembly of components which may be viewed in various perspectives and for purposes of simplified description will be discussed as viewed in two planes. A first plane of operation may be viewed in Figures 2 and 3 including a striker forkbolt 20 rotatable about a first axis 22. In addition, striker loop 24 is shown engaged to striker forkbolt 20. A pawl 26 rotatable about a second axis 28 includes a radially extending member 30 shown engaged with a cooperating abutment surface 32, thereby defining a restriction of rotation of striker forkbolt 20. This completes the description of the positional inter-relationship of pawl 26 and striker forkbolt 20, defining a latched mode of operation. Figure 3 illustrates the positional inter-relationship of striker forkbolt 20 and pawl 26 to define an ajar mode of operation. As is illustrated, the radially extending member 30 is rotatably displaced to a position which provides no restriction of rotation of striker forkbolt 20. Figures 2, 3, 4 and 5 provide views of the first and second planes of the present invention, illustrating the mechanism which establishes the position of pawl 26 including release lever 34 which is rotatably engaged with pawl 26. Release lever 34 is drivingly engaged with actuator lever 36 which is rotatably secured about third axis 38. A release lever holder 40 is rotatably fixed about fourth axis 42 and defines an abutment surface 44 engageable with cooperating surface 46 of actuator lever 36 to define the ajar mode of operation shown in Figure 3. As previously illustrated in Figure 3, in the ajar mode of operation, pawl 26 is maintained in a position of rotation free from any engagement with striker forkbolt 20 providing unrestricted rotation between a latched mode of operation as shown in Figures 2 and 4 and a maximum limit of rotation of striker forkbolt 20 almost reached in Figure 5. As shown in Figures 4 to 6, release lever holder 40 includes a cam-follower portion 50 which follows a cam profile 51 defined substantially by radius R1 and R2 defined on striker forkbolt 20. Upon rotation of striker forkbolt 20 to an open position cam-follower 50 is displaced laterally by a dimension equal to R2 minus R1 thereby releasing abutment surface 44 from cooperating abutment surface 46 permitting actuator lever 36, release lever 34, and pawl 26 to be compliantly urged by a spring into contact with cooperating abutment surface 32 of radially extending surface 54 of striker forkbolt 20, therein defining an open mode of operation. A final mode of operation is defined by the consequence of incomplete closure of door 10, whereupon striker forkbolt 20 engaged with striker loop 24 is partially rotated about first axis 22 such that radially extending member 30 engages with a cooperating abutment surface 32 defined on striker forkbolt 20. The angular restriction of rotation defined by engagement of the respective structures establishes a relative range of rotation of pawl 26 and striker forkbolt 20 which is referred to as the safety mode of operation. Further closing force imposed upon door 10 causes further rotation of striker forkbolt 20 to accomplish the latched mode of operation illustrated in Figures 2 and 4. It may be noted that actuator lever 36 can be rotatably displaced from a latched mode of operation to an ajar mode of operation by an actuator establishing a selected position by electromotive force or manually operated cable 60.

Fig. 5 shows the configuration at the end of the ajar mode just before reaching the open position. The release lever 34 holds the pawl 26 away from the radially extending abutment surfaces 32, which have just passed beyond the nose of radially extending member 30. Fig. 5 shows an artificial transition stage just after the pawl 26 has cleared the safety mode abutment surface and where further rotation of the forkbolt 20 has in the meantime caused the release lever holder 40 to withdraw from its "hold" position for the ajar mode (at cam distance R₂), permitting the pawl 26 to rest its radially extending member 30 on cooperating abutment surface 32 of forkbolt 20.

Claims

A lock apparatus for establishing different mode of operation when locking a door (10) by providing a range of positional interrelationships with respect to a fixed structure including a striker (24) secured to said fixed structure, which is selectively engageable with a striker forkbolt (20) secured to said door (10) and rotatable about a first axis (22), said apparatus comprising:

a striker forkbolt (20), which is selectively engageable with said striker, which is securable to said door (10) and which is rotatable about a first axis (22) to predetermined angular positions with respect to said striker (24);

means to selectively restrict the angle of rotation of said striker forkbolt (20) to accomplish four modes of operation;

a latched mode of operation in which said striker forkbolt (20) is engaged with said striker (24) and restricted from displacement;

an ajar mode of operation in which free rotation of the forkbolt from the latched position is allowed upon rotation of the forkbolt by the striker during unimpeded opening of the door to a maximum limit of rotation at which the striker loop has been liberated;

an open mode of operation which corresponds to said maximum limit of rotation of said striker-forkbolt (20); and

a safety mode of operation in which during subsequent closing upon passing a second limit of rotation reopening beyond said second limit is then blocked and in which a limited range of displacement between said door (10) and said fixed structure is allowed;

wherein said means to selectively restrict the angle of rotation of said striker forkbolt (20) comprises a pawl (26) selectably rotatable about a second axis (28) having a first radially extending portion (30) selectably engageable with first and second cooperating radially extending abutment surfaces defined on said striker forkbolt (20) to restrict rotation thereof;

wherein said pawl (26) is maintained in a first condition engaging said first radially extending abutment surface so as to retain said striker forkbolt (20) at a first limit of rotation thereby defining said latched mode of operation;

and wherein said pawl (26) is maintained in a second condition preventing said pawl (26) from engaging said striker forkbolt (20) to define said ajar mode of operation; said pawl (26) is maintained in a third condition to define said open mode of operation; and, said pawl (26) is maintained in a fourth condition engaged with said second cooperating radially extending abutment surface of said striker forkbolt (20) to define said safety mode of operation;

characterized by a first member (34) pivotally mounted on the second axis (28) in rotational engagement with said pawl (26) such that in the ajar mode of operation said first member (34) assumes a position rotated away from said striker forkbolt (20) so as to hold the pawl (26) in said second condition in which it is prevented from engagement with the striker forkbolt (20), whereas during said open mode of operation said pawl (26) is compliantly urged into engagement therewith.
The apparatus of claim 1 wherein said means to selectively restrict the angle of rotation of said striker-forkbolt (20) comprises:
means for selectively restricting rotation of said first member (34) thereby defining said second condition of said pawl (26) in which said pawl (26) is prevented from engaging with said striker-forkbolt (20) to define said ajar mode of operation.
The apparatus of claim 2 wherein said means for selectively restricting rotation of said first member (34) comprises:

a second member (36) drivingly engaged to said first member (34); and

means for selectively restricting rotation of said second member (36) thereby defining said second condition of said pawl (26) in which said pawl (26) is prevented from engaging said striker forkbolt (20) to define said ajar mode of operation.
The apparatus of claim 2 wherein said means to selectively restrict the angle of rotation of said first member (34) comprises:

a second member (36) drivingly engaged to said first member (34); and

a third member (40) selectively engageable with cooperating abutment surfaces (46) defined on said second member (36) restricting rotation of said second member (36) upon engagement therewith and thereby defining said second condition of said pawl (26) in which said pawl (26) is prevented from engaging said striker forkbolt (20) to define said ajar mode of operation.
The apparatus of claim 1 wherein said pawl (26) is rotatably connected to a force actuator (60) defining a rotary position thereof including a first rotary position defining said latched mode of operation and a second rotary position defining said ajar mode of operation.
The apparatus of claim 4 wherein said third member (40) is disengaged from said cooperating abutment surface (46) defined on said second member (36) in response to a force applied thereto by an abutting surface (51) defined on said striker forkbolt (20) to establish said safety mode of operation.