Note: Descriptions are shown in the official language in which they were submitted.
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POWER DOOR LATCH ASSEMBLY
Field of Invention
This present invention relates to a latch assembly for latching and unlatching
a member
to and from a pillar. In particular, the present invention relates to a power
door latch assembly
for securing and unsecuring a vehicle door.
Background of the Invention
A typical motor vehicle door is mounted in a door frame on the vehicle and is
movable
between open and closed positions. Usually the door is held in a closed
position by the latching
engagement between a spring-biased ratchet pivotally mounted inside the door
latch and a U-
shaped striker secured to the door frame. The ratchet is most often spring-
biased toward the
unlatched position to release the striker and is maintained in the latched
position to hold the
striker by a spring-biased pawl or other mechanical structure. The ratchet
cannot pivot to release
the striker until the pawl is moved.
The majority of these door latches are exclusively manually operated both to
unlatch the
door and to relatch the door. Typically, manual release handles are provided
on the inside and
outside of the door to release the ratchet from the striker by moving the pawl
so that the door can
be opened. The door is closed and relatched by manually pivoting the door so
that the ratchet
impacts the striker with sufficient force to pivot the ratchet to the latched
position against the
spring force exerted by the ratchet spring.
It is often difficult, however, to completely close and latch manually
latching vehicle
doors on current model vehicles because the desire to reduce vehicle weight
and to improve fuel
economy has led engineers to design vehicles with relatively thin and
lightweight doors. Often
relatively hard door seals are used with these thin, lightweight doors to
improve sealing around
the door, particularly at high driving speeds. Because many vehicle doors are
relatively
lightweight and have relatively hard door seals, many vehicle doors often have
insufficient
inertial energy when pushed closed to compress these hard door seals and fully
pivot the ratchet
to the latched position to latch the door.
Power assisted door latch assemblies have been developed to overcome the
problems
associated with latching doors with lightweight construction and hard door
seals. Power assisted
door latch assemblies allow low inertial energy or "soft" closure of the
lightweight doors without
the need to slam the door even with the increased seal pressure that results
from relatively hard
door seals. Existing power assisted door latch assemblies typically function
to latch a vehicle
door in one of two ways: 1) by forcing the ratchet to pivot in the closing
direction after
engagement with the striker or 2) by forcing the striker to move in a door-
closing direction after
the striker is fully engaged with the ratchet.
Use of either type of power assisted door latch assembly decreases the noise
associated
with door closing and decreases the manual effort needed to completely close
the door. Power
assisted door latch assemblies are disclosed by Ishikawa (US 4,986,579),
Kobayashi (US
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5,273,324) and Dowling (US 5,520,425). In Ishikawa, the door latch assembly
includes an
electric motor for rotating the spring-biased ratchet from the partially
closed to the fully closed
position, and an electric switch for activating and deactivating the electric
motor. In Kobayashi,
the door latch assembly includes a rotatable lever for rotating the ratchet
plate into the fully
closed position, an electric motor for manipulating the lever, and a
mechanical linkage extending
between the lever and the ratchet plate for rotating the ratchet plate into
the fully closed position.
In Dowling, the door latch assembly includes a motor driven gear, and a
flexible wire extending
between the driven gear and the ratchet for rotating the ratchet from the
partially closed to the
fully closed position. However, Ishikawa requires a complex rotary actuator
for operating the
switch, whereas the mechanical link and the flexible wire used respectively in
Kobayshia and
Dowling inefficiently transfers mechanical torque between the electric motor
and the ratchet
plate.
Latch assemblies which provide both power assisted opening and power assisted
closing
are also in use. In these power assisted latch assemblies, the same source of
power, typically an
electric motor mounted within the vehicle door, is used both to open the latch
and to close the
latch. The mechanical locking mechanism and some door opening handles can be
eliminated
from the vehicle door when these latch assemblies are used.
Power assisted opening and closing latch assemblies are taught by Bernard (US
4,664,430), Kleefeldt (US 4,518,180) and Tamiya (US 5,232,253). These types of
latching
assembly are often advantageously used with powered sliding vehicle doors in
which the latch
must be released before the power door opening mechanism can be actuated to
open the door.
Bernard uses a cylindrical ratchet plate and a disc rotatably mounted on a
common shaft, a pawl
pivotally mounted on the disc for engagement with the ratchet plate, and an
electric screw drive
for rotating the disc between an open latch position and a close latch
position. Kleefeldt uses a
motor-driven gear and a sliding toggle linkage mechanically coupled to the
driven gear for
opening and closing the ratchet. Tamiya uses a rack-driven link for rotating
the ratchet from the
open position to the closed position, and a lever coupled to the link for
releasing the pawl from
the ratchet to allow the ratchet to be rotatably driven back to the open
position. However,
Bernard stresses the electric motor by using the motor as brake to retain the
ratchet plate in the
closed position, whereas the latching mechanisms taught by Kleefeldt and
Tamiya may not be
reliable in environments where the door is forcefully closed into the latch.
Also, the sliding
toggle linkage used by Kleefeldt limits the mechanical torque which is
ultimately applied to the
ratchet.
Accordingly, there remains a need for a simple., cost-effective power-assisted
door latch
assembly which efficiently transfers torque from the electric motor to the
ratchet. Further, there
remains a need for a power-assisted door latch assembly which limits the
stress applied to the
electric motor by the ratchet.
Summary of the Invention
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According to the present invention, there is provided a power door latch
assembly which
addresses some of the deficiencies of the prior art.
The power door latch assembly, according to the present invention, comprises a
ratchet
for engaging a door striker, a pawl for engaging a detent surface provided on
the ratchet for
selectively resisting rotation of the ratchet towards the open position, a
rotary actuator for
rotating the ratchet towards the closed position and for disengaging the pawl
from the detent
surface, and a drive actuator for driving the rotary actuator. The drive
actuator includes a prime
mover, an output member in engagement with the rotary actuator, and a
releasable coupling
coupled between the prime mover and the output member for selectively
transferring torque
between the prime mover and the rotary actuator. The power door latch assembly
also includes a
drive controller for controlling operation of the drive actuator. The drive
controller is coupled to
the releasable coupling and is configured for disengaging the prime mover from
the rotary
actuator when the ratchet is disposed in either the open or closed positions.
According to the preferred embodiment of the invention, the door latch
assembly
provides for the power assisted opening and closing of a vehicle door with
respect to a vehicle
door frame between a closed position wherein the door is latched to a striker
mounted on the
door frame and an opened position in which the door is unlatched from the
striker. The door
latch assembly has a ratchet which cooperates with a mouth of a housing to
releasably retain the
striker. The door latch assembly also includes a pivotal pawl mounted in
cooperating relation
with the ratchet for biased movement into a holding position wherein the
ratchet is held (1) in the
secondary latched position against movement toward the unlatched position and
(2) in the
primary latched position against movement toward the secondary latched
position. The pawl can
be moved out of the holding position into a releasing position to allow the
ratchet to move
toward and into the unlatched position. The door latch assembly further
includes a sector gear
constructed and arranged to be moved from a null position in one direction
through a closing
stroke into a closing position and from the closing position through a return
stroke to the null
position and from the null position in an opposite direction through an
opening stroke into an
opening position and from the opening position through a return stroke into
the null position. An
actuator assembly includes a reversible electric motor and a clutch assembly
for selectively
driving the sector gear. The electric motor is operable (1) when energized to
rotate in one
direction to drive the sector gear through the closing stroke thereof and (2)
when energized to
rotate in an opposite direction to drive the sector gear through the opening
stroke thereof. The
sector gear has a closing arm constructed and arranged to cause a movement of
the ratchet from
the secondary latched position thereof to the primary latched position
thereof. The sector gear
has an opening arm constructed and arranged to cause a movement of the pawl
from the holding
position thereof to the releasing position thereof to release the ratchet.
Preferably, the sector gear has a spring for urging the sector gear to move
through the
return strokes thereof from opening and closing positions thereof when the
actuator is de-
energized.
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Preferably the door latch assembly includes an energizing closing switch
constructed and
arranged to be actuated in response to the movement of the ratchet into the
secondary latched
position thereof to energize the electric motor to thereby move the sector
gear through a closing
stroke so that the closing arm causes the ratchet to move from the secondary
latched position
thereof into the primary latched position thereof and a closing de-energizing
switch constructed
and arranged to be actuated in response to the movement of the ratchet into
the primary latched
position thereof to de-energize the electric motor and allow the spring system
to effect a return
stroke of the sector gear. The power operated driving assembly further
includes a manually
operable opening energizing switch constructed and arranged to energize the
electric motor in
response to a manual actuation thereof to move the sector gear through an
opening stroke so that
the opening structure thereof causes the ratchet to move out of the primary
position thereof to
allow the door to be moved into an open position and a timer closing de-
energizing switch
constructed and arranged to be actuated in response to the movement of the
pawl into the
releasing position thereof to de-energize the electric motor after a
predetermined time and allow
the spring system to effect a return stroke of the sector gear.
Preferably, the ratchet and the sector gear are pivotally mounted about a
common axis
and the pawl is pivotally mounted about an axis that is parallel to the common
axis.
Preferably, the door latch assembly includes a housing having a striker
receiving opening
therein constructed and arranged to be mounted in the vehicle door so that the
opening receives
the striker during a door closing movement. The ratchet is pivotally mounted
on the housing
with the striker engaging structure facing outwardly within the opening when
the ratchet is in the
unlatched position. The latching structure extends within the opening when the
ratchet is in the
latched positions. The housing carries the pawl, the sector gear and the power
operated driving
assembly.
Brief Description of the Drawings
The present invention will now be described, by way of example only, with
reference to
the accompanying drawings, in which:
FIG. 1 is an elevational view of the left side of a conventional four-door
vehicle;
FIG. 2 is an isolated fragmentary perspective view of the interior of a front
door of the
vehicle shown in FIG. 1;
FIG. 3 is a perspective view at a first side of a power assisted door latch
assembly
embodying the principles of the present invention;
FIG. 4 is a perspective view of a second side of the power assisted door latch
assembly
shown in FIG. 3;
FIG. 5 is a perspective view similar to FIG. 3 of the door latch assembly with
a first
cover and a second cover removed;
FIG. 6 is a perspective view similar to FIG. 4 of the door latch assembly with
the second
cover removed;
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FIG. 7 is a schematic view showing a power operated driving assembly, a power
source,
a voltage source and controller for the door latch assembly;
FIG. 8 is an elevational view showing a plurality of parts of the door latch
assembly
including a ratchet, a pawl, a sector gear, a first switch member and a second
switch member in a
primary latched configuration with a conventional striker shown in sectional
view mounted on a
door frame shown in fragmentary view;
FIG. 9 is a view similar to FIG. 8 showing the pawl in a releasing position
and the sector
gear in an opening position;
FIG. 10 is a view similar to FIG. 8 showing the door latch assembly in an
unlatched
position;
FIG. 11 is a view similar to FIG. 8 showing the door latch assembly in a
secondary
latched position;
FIG. 12 is a view similar to FIG. 11 showing the door latch assembly in a
secondary
latched position and showing the sector gear partially rotated in a closing
direction; and
FIG. 13 is a view similar to FIG. 12 showing the ratchet in a primary latched
position and
showing the sector gear fully rotated in a closing direction.
Detailed Description of the Preferred Embodiment
FIG. 1 shows a left side elevational view of the exterior of a conventional
motor vehicle
10 that has a front door 12 and a back door 14. Each door 12, 14 has an
exterior handle 16 and a
door latch opening button 18. The front door 12 has a conventional key-
operated lock cylinder
20 to lock and unlock the door 12.
A power operated door latch assembly 22 constructed according to the
principles of the
present invention is mounted on each door of the vehicle 10 for the power
assisted latching and
unlatching of each door.
FIG. 2 shows an isolated view of the inside of the front door 12. Two hinges
24 are
secured to a first inner edge 28 of the door 12 to pivotally mount the door 12
to a door frame on
the vehicle 10 in a conventional manner so the door can be moved between open
and closed
positions. A power operated door latch assembly 22 is mounted on a second
outer edge 30 of the
door. The door 12 has an interior door release switch 32 to unlatch the door
latch assembly 22
with power assistance and an interior manual door release handle 34 to
manually unlatch the
door 12 using a manual override.
A conventional U-shaped striker is rigidly secured to the door frame of the
vehicle 10 in
a conventional manner. When the door 12 is moved to the closed position, the
door 12 pivots
into the door frame and the door latch assembly 22 impacts the striker to
latch the door 12.
Referring to FIGS. 3 and 4, the door latch assembly 22 includes a housing 36
and a first
cover 38 and a second cover 40 secured to the first cover 38. The covers 38,
40 are secured to
the housing 36 by conventional staking pins 42, 44 or other suitable
fasteners. The housing 36
engages threaded holes 46 to mount the door latch assembly 22 to a door 12
with conventional
bolts or other suitable means. Housing 36 has a mouth structure 31. Tab 93 on
the second cover
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40 extends through a slot 95 in the first cover 38 and two tabs 97, 99 on the
first cover 38 clip
over the edge of the second cover 40 at 101, 103 to close the door latch
assembly 22.
Referring to FIG. 5, the housing 36 has a conventional bushing 58 for
rotatably mounting
the ratchet 50 on pin 44 (FIG. 6) between an unlatched position and a primary
latched position.
Ratchet 50 has a conventional detent fork structure having a notch 110
presenting a primary .
detent surface 126. The ratchet 50 has a secondary detent 128 spaced
circumferentially from the
primary detent 126. The ratchet 50 has a contoured edge diametrically opposite
the notch 110
presenting a cinch drive area 132 and a release clearance area 114. Ratchet 50
cooperates with
the mouth 31 to engage and cinch the striker 106 (FIG. 8) to hold the door
closed.
A ratchet spring 118 (FIG. 8) is confined within an arcuate slot of the
ratchet 50. The
ratchet spring 118 extends between a wall portion 120 of the housing 36 and a
tab 122 secured to
the inside of the ratchet 50. The ratchet 50, therefore, is mounted for biased
pivotal movement
into the unlatched position.
Housing 36 has a conventional bushing 56 for rotatably mounting the pawl 52 on
pin 42
(FIG. 6). Arcuate slot 66 receives connecting arm 64 and allows travel of the
pawl 52 between a
latching position and a full release overtravel position. Pawl spring 68
extends between the
housing 36 and the pawl 52 to bias the pawl 52 against the ratchet 50 to
follow the contours of
the circumference thereof. Housing 36 has a channel for retaining the pawl
spring 68.
Referring to FIG. 6, a sector gear 54 is commonly mounted on pin 44 on a side
of the
housing opposite the ratchet 50. Sector gear 54 is mounted in such a manner
that the sector gear
54 is able to rotate relative to or independently of the ratchet 50. The
sector gear 54 has an
opening arm 70 which extends tangentially from a toothed portion 55. The
sector gear 54 also
has a closing arm 72 which extends axially from the teeth portion 55. Coil
springs 74 are
mounted around sector bearing cylinder 59 with a first end 77 engaging the
housing 36 and a
second end 79 engaging the sector gear 54. Springs 74 bias sector gear 54 into
a null position.
Housing 36 has an arcuate slot 57 through which closing arm 72 extends for
engagement
with cinch drive area 132 of ratchet 50. As sector gear 54 rotates, it will
rotate independently of
the ratchet 50 until it engages the cinch drive area 132. In the release
direction, the travel of
sector gear 54 is not obstructed by the ratchet 50 due to the release
clearance area 114. Thus,
sector gear 54 has a "lost motion" relative to the ratchet 50.
A release lever 62 is commonly mounted on housing bushing 56 on opposite sides
of the
housing 36 from the pawl. Housing 36 has an arcuate slot 66 through which
connecting arm 64
(FIG. 5) extends coupling the pawl 52 and the release lever 62 together for
pivotal movement as
a single unit. Release lever 62 has a hub from which arms 112, 117 (FIG. 8),
134, 136 and 137
radially extend.
Pin 42 provides pivotal support for the pawl 52 and release lever 62 and the
pin 44
provides pivotal support for the ratchet 50 and the sector gear 54. Therefore,
the pin 44 defines a
first pivot axis for both the ratchet 50 and the sector gear 54 and the pin 42
defines a second
pivot axis for the pawl 52 and release lever 62. These two axes are
essentially parallel.
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A first electrical switch 76 (FIG. 5) is mounted on the housing 36 and
positioned to
engage the outer cam surface of the release clearance area 114 as the ratchet
50 rotates. The
pivotal movement of the ratchet 50 will switch or toggle the switch 76 between
an "on" state and
an "off' state. A second electrical switch 78 is mounted on housing 36 and
positioned to engage
arm 112 of the release lever.62. The pivotal movement of the release lever 62
will switch or
toggle the switch 78 between an "on" state and an "off' state. Each switch 76,
78 has two
conventional electrical connectors 81 (FIG. 3) to connect the switches to a
controller 108 (FIG.
7).
Wire 80 and bowden wire 82 engage arm 137 of release lever 62. The outer
sheath of the
bowden wire 82 is mounted to the housing to effect actuation of the bowden
wires. Each end of
the wires 80, 82 has a cap 87, 89 which allows the wires 80, 82 to slide
relative to the release
lever 62. Thus, wires 80 and 82 do not interfere with the movement of the pawl
52 between the
holding and releasing positions during power assisted door opening and
closing.
Referring to FIG. 7, actuator 96 is mounted on the face of the plate 40.
Actuator 96
includes a motor 98 and a clutch assembly to selectively drive the sector gear
54. The second
cover 40 has an opening 48 (FIG. 4) through which a drive shaft 100 extends. A
drive gear 104 is
mounted on the drive shaft 100 and engages the sector gear 54 to provide
torque amplification
for movement of the sector gear 54 and the pawl 52. The motor 98 and clutch
assembly 102 are
energized by the vehicle's electrical system which is schematically
represented as a voltage
source 107. The motor 98, clutch assembly 102 and the drive shaft 100 are
mounted within the
door 12. A portion of the drive shaft 100 is carried in the door latch
assembly 22 to support the
drive gear 104 in the housing 36 and engage the sector gear 54 with the drive
gear 104.
A controller 108 controls the motor 98 and clutch assembly 102 by energizing
and de-
energizing the same in response to switching signals from the switches 18 and
32 on the door 12,
a remote control 199 and the switch members 76, 78 in the door latch assembly
22.
The covers 38, 40 are preferably made of steel or other appropriate material.
The ratchet
50 and first pawl member 52 are preferably made of steel or other suitable
metal, having a plastic
cover 94. The release lever 62 and the sector gear 54 can be made of any
suitable plastic or
metal. The conventional bushings 56, 58 are integral with the housing 36 and
are preferably a
composite material such as nylon.
The Primary Latched Position
FIG. 8 shows the neutral or equilibrium configuration of the door latch
assembly 22
when the door is closed and latched. The ratchet 50 is in a primary latched
position and the
striker 106 is held in a notch 110 in the ratchet 50 to hold the door closed.
The ratchet 50 is held
in the primary latched position by the pawl 52.
Arm 112 on the release lever 62 holds the switch 78 in a depressed position.
Release
clearance area 114 of the ratchet 50 maintains the first switch 76 in a
depressed position. The
sector gear 54 is in the null position.
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There is a small gap or design clearance 116 between the opening arm 70 on the
sector
gear 54 and arm 117 when the latch assembly 22 is in the primary latched
position and the sector
gear 54 is in the null position.
In this position, the clutch assembly 102 is de-energized to prevent any
torque from the
ratchet 50 or the sector gear. 50 from being applied to the motor 98.
Unlatching and Opening the Door with Power Assistance
To unlatch the door latch assembly 22 with power assistance, any one of the
switches 18
or 32 on the door 12 or a switch 119 on the remote control 199 is actuated.
Each switch 18, 32,
119 functions as an energizing switch and is independently operable to
energize the motor 98.
When the motor and clutch assembly 102 are energized, the motor 98 rotates the
drive gear 104
in a first rotational direction to drive the sector gear 54 out of the null
position in an opening
direction through an opening stroke to an opening position. The opening
direction of the sector
gear 54 is the counterclockwise direction in FIGS. 8-9.
As the sector gear 54 pivots from the null position to its opening position,
the releasing
arm 70 contacts the arm 117 of release lever to pivot the pawl 52 from its
latching position to its
releasing position. Ratchet 50 pivots from the primary latched position to an
unlatched position
to release the striker 106 so the door can be opened.
Although the ratchet spring 118 provides enough force to pivot the ratchet 50
from the
primary latched position to the unlatched position when the pawl 52 is moved
to the releasing
position, it can be understood that the seal pressure exerted by the door seal
on the door also
tends to move the door latch assembly 22 and the striker apart when the door
is unlatched which
tends to rotate the ratchet 50 to the unlatched position. However, it will
also be appreciated that
due to the torque amplification of the drive gear 104 acting upon the sector
gear 54, the potential
energy stored in the ratchet spring 118 will be greater than prior art
devices. Consequently, the
ratchet 50 will be able to pivot to the unlatched position with greater force
than prior art devices
and without increasing the size of the motor 98.
When the pawl 52 is in the releasing position, the arm 112 is moved away from
the
second switch 78 to toggle the second switch 78. When the ratchet 50 pivots
from the primary
latched position to the unlatched position, the cam surface of the release
clearance area 114 of
the ratchet 50 moves out of contact with the first switch 76 to toggle the
first switch 76. In
response to the toggling of the first switch 76, the control circuitry 108 de-
energizes the motor
98. The actuator 96 holds the sector gear 54 in its opening position until the
ratchet 50 has
pivoted to the unlatched position. When the clutch assembly 102 is disengaged,
the sector gear
54 pivots from the opening position through a return stroke back to its null
position under the
spring force provided by one of the sector springs 74. Consequently, any
torque from the ratchet
50 or the sector gear 50 is precluded from being applied to the motor 98.
Closing and Relatching the Door with Power Assistance
Referring to FIGS. 10 to 13, the door latch assembly 22 engages striker 106
which enters
the mouth 31 and engages the ratchet 50 which responsively pivots from the
unlatched position
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toward the primary latched position. Because of the door seal pressure and the
relatively
lightweight of the vehicle door, the door may not have sufficient momentum to
rotate the ratchet
50 all the way to the primary latched position.
Usually, the ratchet 50 is rotated to allow the pawl 52 to abut secondary stop
128. The
ratchet 50 is retained in the secondary latched position. When the door latch
assembly 22 is in
the secondary latched position, the striker 110 is captured in the notch 110
and the door is
partially closed and cannot be reopened without moving the pawl 52 to its
releasing position.
When the pawl 52 engages the secondary stop 128, the arm 112 depresses the
second
switch 78. In response, the controller 108 energizes the motor 98 and clutch
assembly 102. The
motor 98 rotates the drive gear 104 in a second direction to cause the sector
gear 54 to pivot in a
closing direction through a closing stroke in a closing direction. The
cinching arm 72 on the
sector gear 54 contacts cinching stop 132 of the ratchet 50 so that continued
movement of the
sector gear 54 in the closing direction pivots or cinches the ratchet 50 from
the secondary latched
position to the primary latched position. The pawl 52 engages primary detent
126 to retain the
ratchet 50 in the primary latched position.
When the ratchet 50 returns to the primary latched position, the releasing
stop 114 of the
ratchet 50 depresses and toggles the first switch 76. Both switches 76, 78 are
now depressed.
The first switch 76 functions as the closing de-energizing switch which
signals the controller
108, in responsive to the movement of the ratchet 50 moving into the primary
latched position, to
de-energize the motor 98 and disengage the clutch assembly 102. When the
clutch assembly 102
is de-energized, springs 74 return the sector gear 54 from the closing
position through a return
stroke to the null position. The drive gear 104 and the drive shaft 100 freely
rotate with the
sector gear 54 as it returns to the null position. When the sector gear 54 is
back in the null
position, the door latch assembly 22 is again in the neutral or equilibrium
position with any
torque from the ratchet 50 or the sector gear 50 being precluded from being
applied to the motor
98.
Unlatching and Opening the Door with Manual Override
The opening button 18 functions as an electrical switch when it is partially
depressed
through its actuation stroke and functions as a mechanical release means when
it is fully
depressed through its actuation stoke. Therefore, the opening button 18 is
used to open the door
with power assistance by partially depressing the button 18 through its
actuation stroke and is
used to open the door 12 manually with a mechanical override by fully
depressing the button 18
through its full actuation stroke. The interior door release handle 34 on the
inside of the door 12
is used to unlatch the door 12 manually with mechanical override.
The interior door release handle 34 is operatively connected through Bowden
wire 80 to
the pawl 52. By actuating the interior door release handle 34, the Bowden wire
80 is pulled to
move the pawl 52 from its holding position to its releasing position to
disengage the pawl 52
from the ratchet 50. The ratchet 50 then moves to its unlatched position under
the spring force of
the ratchet spring 118 and the seal load on the door 12.
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, .,.
--*u esu 1:3W:J44465 ; # 5
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01-03-2001 CA 02362889 2001-08-20 CA 000000164
= The bntton 18 on the door 12 is atechanically iinked in a eonventtonal
manner to the rclaesc
wite 82. If the button 18 is fully deprsseed, it pulls the wire 82 in a
direction to move the pawl 52
from its hoiding position to its releasitg position to releasc the ratchet 50.
It ean be $ppreciated that the manual override provided by the button l 8 and
the interior handle
34 cm oelaso the ratchot 50 from either the prirnary latched position or
secondary latched position to
opcn thc door 12. Each manual mJeaac 18, 34 feanctlons independently and each
holds the pawl 52 in
the releasing posetion as long as the tuanual release 19 or 34 is held in an
actuated position by the
person opening the door 12.
It is contarnplateci to use many conventional manual neleaae handles to
uniatch the door lttch
assembly 22. It is also contemplated to tso the door latch as,stmbly 22 with
any convatytional interior
or exterior elsetrohic door handle. The door lateh atoembly 22 can also be
used with any oonventional
nnanual or power operated door locking and unlocking system.
It can be understaod that to close the open door and relatch the sama in the
primary latched
poaition without power assistance, for example, in the event of a power
fallume, the door 12 is simply
closed with greater force than is ordinarily used wben power assistance is
available. The manual
closing force applied to the door 12 must be suftientto rotate the ratchet 50
to the primary latched
position so the pawl 52 can move back into its holding position and engage the
first tooth portion 109
of the ratchet 50. T7te door 12 must be closed hard enough to sufficiantly
comprm the door seal on
the door framc to allow ralatchinR.
It is understaod that the illustrsted operation is exeanpluy only and rAt
intended to be litniting.
The door latch assembly 22 can be used in other applications. The door latch
asseotbly can be used,
for example, on a powared sliding door of a typo frequently foutul in van-typc
vehicles where tlu latch
Itas to be releasad before the power door opening mechanism can start. It is
contemplated to use the
door ]atch naembly in a vehicla door which inclucie* a power mschania:n to
move t!x door from the
open position to the aecondary latched position with power assistance.
The Ahovc-described embodimmt of the invention is iryunded to be an example of
ihe prasent
invention and alterations and modifications may be effected thcreto, by thox
of skill in the art, without
departing from tha scope of the inventlon, as dofined in the appended claims.
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