U.S. patent application number 10/092727 was filed with the patent office on 2002-09-12 for reclining mechanism for vehicle seat.
This patent application is currently assigned to Araco Kabushiki Kaisha. Invention is credited to Asano, Makoto.
Application Number | 20020125756 10/092727 |
Document ID | / |
Family ID | 26422907 |
Filed Date | 2002-09-12 |
United States Patent
Application |
20020125756 |
Kind Code |
A1 |
Asano, Makoto |
September 12, 2002 |
Reclining mechanism for vehicle seat
Abstract
A reclining mechanism for a vehicle seat composed of a first arm
member for attachment to a frame structure of a seat cushion or a
back rest of the vehicle seat; a second arm member for attachment
to a frame structure of the other of the back rest or the seat
cushion, the second arm member being connected with the first arm
member by means of a hinge pin for relative rotation about the
hinge pin and having a pair of diametrically opposed semi-circular
ratchet portions concentric with the hinge pin; a pair of
diametrically opposed slide pawls slidably coupled with the first
arm member in a radial direction with respect to the hinge pin to
be moved toward and away from the ratchet portions of the second
arm member; and a cam element slidably coupled with the first arm
member in a lateral direction perpendicular to the slide pawls and
disposed between the slide pawls, the cam element being operatively
connected with the hinge pin to be moved by rotation of the hinge
pin in the lateral direction for engaging the slide pawls with the
ratchet portions of the second arm member and for disengaging the
slide pawls from the ratchet portions of the second arm member,
wherein the hinge pin is loaded by a torsion spring assembled
thereon to bias the cam element in the lateral direction for
maintaining the slide pawls in engagement with the ratchet portions
of the second arm member.
Inventors: |
Asano, Makoto; (Toyota-shi,
JP) |
Correspondence
Address: |
REED SMITH LLP
Suite 1400
3110 Fairview Park Drive
Falls Church
VA
22042
US
|
Assignee: |
Araco Kabushiki Kaisha
|
Family ID: |
26422907 |
Appl. No.: |
10/092727 |
Filed: |
March 8, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10092727 |
Mar 8, 2002 |
|
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09337126 |
Jun 21, 1999 |
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6390557 |
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Current U.S.
Class: |
297/367R |
Current CPC
Class: |
B60N 2/236 20150401 |
Class at
Publication: |
297/367 |
International
Class: |
B60N 002/48 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 22, 1998 |
JP |
10(1998)-175068 |
Mar 25, 1999 |
JP |
11(1999)-81926 |
Claims
What is claimed is:
1. A reclining mechanism for a vehicle seat, comprising: a first
arm member for attachment to a frame structure of a seat cushion or
a back rest of the vehicle seat; a second arm member for attachment
to a frame structure of the other of the back rest or the seat
cushion, the second arm member being connected with the first arm
member by means of a hinge pin for relative rotation about the
hinge pin and having a semi-circular ratchet portion concentric
with the hinge pin; a slide pawl slidably coupled with the first
arm member in a radial direction with respect to the hinge pin to
be moved toward and away from the ratchet portion of the second arm
member; and a cam element slidably coupled with the first arm
member in a lateral direction perpendicular to the slide pawl and
operatively connected with the hinge pin to be moved by rotation of
the hinge pin in the lateral direction for engaging the slide pawl
with the ratchet portion of the first arm member and for
disengaging the slide pawl from the ratchet portion of the first
arm member; wherein the hinge pin is loaded by a torsion spring
assembled thereon to bias the cam element in the lateral direction
for maintaining the slide pawl in engagement with the ratchet
portion of the second arm member, wherein the slide pawl is formed
at its outer end with a semi-circular toothed portion to be engaged
with the ratchet portion of the first arm member and its inner end
with a pair of laterally spaced projections for engagement with a
flat end surface of the cam element, and wherein the cam element is
formed at the flat end surface thereof with a pair of laterally
spaced recesses to be engaged with the spaced projections of the
slide pawl for permitting disengagement of the slide pawl from the
ratchet portion of the first arm member.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a reclining mechanism for a
vehicle seat for adjusting an inclined angle of a back rest of the
seat relative to a seat cushion.
[0003] 2. Description of the Prior Art
[0004] Disclosed in Japanese Patent Laid-open Publication No.
8-52040 is a reclining mechanism for a vehicle seat which is
composed of a pair of arm members for attachment to a frame
structure of a seat cushion and to a frame structure of a back
rest, the arm members being connected by means of a hinge pin for
relative rotation about the hinge pin, a slide pawl slidably
coupled with one of the arm members to be moved in a radial
direction with respect to the hinge pin, and a cam element mounted
on the hinge pin for rotation therewith and engaged with the slide
pawl for maintaining the slide pawl in engagement with a ratchet
portion of the other of the arm members and for disengaging the
slide pawl from the ratchet portion when it is rotated with the
hinge pin. In the reclining mechanism, the relative rotation of the
arm members is restricted by engagement of the slide pawl with the
ratchet portion to lock the back rest at an inclined angle and is
permitted by disengagement of the slide pawl from the ratchet
portion for adjustment of the inclined angle of the back rest.
[0005] In the reclining mechanism, the engagement of the slide pawl
with the ratchet portion of the arm member is maintained in a
condition where the slide pawl is pressed by engagement with a
portion of the cam element. When the cam element is rotated with
the hinge pin to disengage the slide pawl from the ratchet portion
of the arm member, the slide pawl is retracted by engagement with a
portion of the cam element. If the reclining mechanism is applied
with a load, the slide pawl is slightly rotated due to an error in
assembly of the component parts of the reclining mechanism. This
results in looseness in engagement of the slide pawl with the
ratchet portion of the arm member.
SUMMARY OF THE INVENTION
[0006] It is therefore a primary object of the present invention to
provide a reclining mechanism for a vehicle seat wherein rotation
of the slide pawl is prevented to firmly maintain the engagement of
the slide pawl with the ratchet portion even if the reclining
mechanism is applied with a load.
[0007] According to the present invention, the object is
accomplished by providing a reclining mechanism for a vehicle seat,
which comprises a first arm member for attachment to a frame
structure of a seat cushion or a back rest of the vehicle seat, a
second arm member for attachment to a frame structure of the other
of the back rest or the seat cushion, the second arm member being
connected with the first arm member by means of a hinge pin for
relative rotation about the hinge pin and having a semi-circular
ratchet portion concentric with the hinge pin, a slide pawl
slidably coupled with the first arm member in a radial direction
with respect to the hinge pin to be moved toward and away from the
ratchet portion of the second arm member, and a cam element
slidably coupled with the first arm member in a lateral direction
perpendicular to the slide pawl and operatively connected with the
hinge pin to be moved by rotation of the hinge pin in the lateral
direction for engaging the slide pawl with the ratchet portion of
the first arm member and for disengaging the slide pawl from the
ratchet portion of the first arm member, wherein the hinge pin is
loaded by a torsion spring assembled thereon to bias the cam
element in the lateral direction for maintaining the slide pawl in
engagement with the ratchet portion of the second arm member,
wherein the slide pawl is formed at its outer end with a
semi-circular toothed portion to be engaged with the ratchet
portion of the first arm member and its inner end with a pair of
laterally spaced projections for engagement with a flat end surface
of the cam element, and wherein the cam element is formed at the
flat end surface thereof with a pair of laterally spaced recesses
to be engaged with the spaced projectios of the slide pawl for
permitting disengagement of the slide pawl from the ratchet portion
of the first arm member.
[0008] In a practical embodiment of the present invention, the
first arm member is formed with a first guide groove in a radial
direction with respect to the hinge pin and a second guide groove
perpendicular to the first guide groove, and the slide pawl is
slidably coupled within the first guide groove while the cam
element is slidably coupled within the second guide groove. For
operative connection of the cam element with the hinge pin, the cam
element is formed with an elongated lateral hole in the lateral
direction perpendicular to the slide pawl, and the hinge pin is
inserted across the lateral hole of the cam element for connection
to the first and second arm members and being engaged with a
portion of the lateral hole of the cam element.
[0009] According to an aspect of the present invention, there is
provided a reclining mechanism for a vehicle seat, which comprises
a first arm member for attachment to a frame structure of a seat
cushion or a back rest of the vehicle seat, a second arm member for
attachment to a frame structure of the other of the back rest or
the seat cushion, the second arm member being connected with the
first arm member by means of a hinge pin for relative rotation
about the hinge pin and having a pair of diametrically opposed
semi-circular ratchet portions concentric with the hinge pin, a
pair of diametrically opposed slide pawls slidably coupled with the
first arm member in a radial direction with respect to the hinge
pin to be moved toward and away from the ratchet portions of the
second arm member, and a cam element slidably coupled with the
first arm member in a lateral direction perpendicular to the slide
pawls and disposed between the slide pawls, the cam element being
operatively connected with the hinge pin to be moved by rotation of
the hinge pin in the lateral direction for engaging the slide pawls
with the ratchet portions of the second arm member and for
disengaging the slide pawls from the ratchet portions of the second
arm member, wherein the hinge pin is loaded by a torsion spring
assembled thereon to bias the cam element in the lateral direction
for maintaining the slide pawls in engagement with the ratchet
portions of the second arm member.
[0010] In a practical embodiment of the reclining mechanism
described above, the slide pawls each are formed at their outer
ends with a semi-circular toothed portion for engagement with each
ratchet portion of the second arm members and at their inner ends
with a pair of laterally spaced projections to be engaged with
opposite flat surfaces of the cam element for maintaining the slide
pawls in engagement with the ratchet portions of the second arm
member, and wherein the cam element is formed with the opposite
flat surfaces thereof with a pair of laterally spaced recesses to
be engaged with the spaced projections of the slide pawls for
permitting disengagement of the slide pawls from the ratchet
portions of the second arm member.
[0011] In such an embodiment described above, it is preferable that
a cam plate is assembled with the cam element to disengage the
slide pawls from the ratchet portions of the second arm member by
engagement therewith when the hinge pin is rotated against the load
of the torsion spring to cause lateral movement of the cam element.
The cam plate is formed with a pair of diametrically opposed cam
slots which are engaged with a pair of cam pins provided on the
slide pawls to disengage the slide pawls from the ratchet portions
of the second arm member when the hinge pin is rotated against the
load of the torsion spring to cause lateral movement of the cam
element. In the embodiment, a movable cam plate may be assembled
with the hinge pin to be rotated with the hinge pin and rotatably
connected with the cam element to cause lateral movement of the cam
element when rotated with the hinge pin, wherein the movable cam
plate is formed with a pair of diametrically opposed cam slots
which are engaged with a pair of cam pins provided on the slide
pawls to disengage the slide pawls from the ratchet portions of the
second arm member when the hinge pin is rotated against the load of
the torsion spring.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] Other objects, features and advantages of the present
invention will be more readily appreciated from the following
detailed description of preferred embodiments thereof when taken
together with the accompanying drawings, in which:
[0013] FIG. 1 is a partly broken front view of a reclining
mechanism in accordance with the present invention;
[0014] FIG. 2 is a vertical sectional view of the reclining
mechanism taken along line 2-2 in FIG. 1;
[0015] FIG. 3 is a cross-sectional view of the reclining mechanism
taken along line 3-3 in FIG. 1;
[0016] FIG. 4 is a front view of a first arm member shown in FIG.
1;
[0017] FIG. 5 is a front view of a second arm member shown in FIG.
1;
[0018] FIGS. 6(a) to 6(c) illustrate a mode of operation of a cam
element in the reclining mechanism shown in FIG. 1;
[0019] FIG. 7 is a vertical sectional view of a first modification
of the reclining mechanism shown in FIGS. 1 to 3;
[0020] FIGS. 8(a) to 8(c) illustrate a mode of operation of a cam
element in the first modification;
[0021] FIGS. 9(a) to 9(c) illustrate a mode of operation of a cam
element in a second modification of the reclining mechanism shown
in FIGS. 1 to 3;
[0022] FIG. 10(a) is a front view of the cam element shown in FIGS.
9(a) to 9(c);
[0023] FIG. 10(b) is a vertical sectional view of the cam element
shown in FIG. 10(a);
[0024] FIG. 11(a) is a front view of a movable cam plate shown in
FIGS. 9(a) to 9(c);
[0025] FIG. 11(b) is a vertical sectional view of the movable cam
plate shown in FIG. 11(a);
[0026] FIGS. 12(a) and 12(b) illustrate a mode of operation of a
cam element in a third modification of the reclining mechanism;
[0027] FIG. 13 is a vertical sectional view of the reclining
mechanism taken along line 4-4 in FIG. 12(a);
[0028] FIG. 14 is a cross-sectional view of the reclining mechanism
taken along line 5-5 in FIG. 12(a); and
[0029] FIG. 15 is a vertical sectional view of a modification of
the reclining mechanism shown in FIG. 13.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0030] Illustrated in FIGS. 1 to 3 is a reclining mechanism for a
vehicle seat in accordance with the present invention, which
reclining mechanism is composed of a first arm member 11 for
attachment to a frame structure of a seat cushion (not shown) of
the vehicle seat, a second arm member 12 for attachment to a frame
structure of a back rest (not shown) of the vehicle seat, a pair of
slide pawls 13 and 14, a cam element 15, a torsion spring 16, a
binge pin 17 and an operation lever 18. The first and second arm
members 11 and 12 are coupled to contain the slide pawls 13, 14 and
cam element 15 therein. The second arm member 12 is connected to
the first arm member 11 by means of the hinge pin 17 for relative
rotation about the hinge pin 17. The reclining mechanism is
assembled with the vehicle seat in such a manner that the second
arm member 12 is locked to the first arm member 11 at a selected
position to retain the back rest at an inclined angle and that the
second arm member is released from the first arm member to permit
adjustment of the inclined angle of the back rest.
[0031] As shown in FIGS. 1 to 4, the first arm member 11 has an
upper portion 11a formed to contain the slide pawls 13, 14 and cam
element 15 and a lower portion 11b for attachment to the frame
structure of the seat cushion. As shown in FIG. 4, the upper
portion 11a of first arm member 11 is formed therein with a
vertical guide groove 11d across a central hole 11c and a lateral
guide groove 11e perpendicular to the vertical groove 11d. The
vertical guide groove 11d is slightly extended outward from the
inner periphery of a circular recess 11f formed in the upper
portion 11a, while the lateral groove 11e is extended to the inner
periphery of the circular recess 11f.
[0032] As shown in FIGS. 1 to 3 and 5, the second arm member 12 has
a lower portion 12a formed to contain the slide pawls 13, 14 and
cam element and an upper portion 12b for attachment to the frame
structure of the back rest. The lower portion 12a of second arm
member 12 is formed with a circular recess 12d concentric with a
central hole 12c. The circular recess 12d and central hole 12c are
formed in the lower portion 12a of second arm member 12 to
correspond with the circular recess 11f and central hole 11c formed
in the upper portion 11a of first arm member 11. The circular
recess 12d of second arm member 12 is formed at its inner periphery
with a pair of diametrically opposed semi-circular ratchet portions
12e.
[0033] The slide pawls 13 and 14 are formed in the same width and
thickness. As shown in FIG. 6, the slide pawls 13 and 14 are formed
at their outer ends with semi-circular toothed portions 13a and 14a
and at their inner ends with flat surfaces 13b and 14b and each
pair of tapered projections 13c and 14c. The thickness of each of
the slide pawls 13, 14 is determined to correspond with a space
defined by the vertical guide groove 11d of first arm member 11 and
the circular recess 12d of second arm member 12, and the width of
each of the slide pawls 13, 14 is determined to correspond with the
width of the vertical guide groove 11d of first arm member 11. The
semi-circular toothed portions 13a, 14a of slide pawls 13, 14 are
positioned to be engaged with and disengaged from the ratchet
portions 12e of second arm member 12. The tapered projections 13c,
14c of slide pawls 13, 14 are formed to be located in the lateral
guide groove 11e of first arm member 11 in a condition where the
slide pawls 13, 14 are maintained in engagement with the ratchet
portions 12e of second arm member 12.
[0034] As shown in FIGS. 6(a)-6(c), the cam element 15 is in the
form of a rectangular plate which is formed at its central portion
with an elongated lateral hole 15a and at its opposite flat
surfaces with each pair of laterally spaced recesses 15b, 15c. The
lateral hole 15a is formed at one side thereof with a radial recess
15d. The thickness of the cam element 15 is determined to
correspond with a space defined by the lateral guide groove 11e of
first arm member 11 and the circular recess 12d of second arm
member 12. The width of cam element 15 is determined to correspond
with the width of lateral groove 11e of first arm member 11, and
the elongated lateral hole. 15a of cam element 15 is formed to
allow rotation and lateral movement of cam element 15 relative to
the hinge pin 17. The laterally spaced recesses 15b, 15c of cam
element 15 each are formed to be brought into engagement with and
disengaged from the laterally spaced projections 13c, 14c of slide
pawls 13, 14. The radial recess 15d of cam element 15 is maintained
in engagement with a radial projection 17a of hinge pin 17.
[0035] During the assembly process of the reclining mechanism, the
slide pawls 13, 14 are slidably engaged with the vertical guide
groove 11d of first arm member 11, and the cam element 15 is
slidably engaged with the lateral guide groove 11e of first arm
member 11 and disposed between the slide pawls 13 and 14.
Thereafter, the second arm member 12 is coupled at its lower
portion 12a with the upper portion 11a of first arm member 11 for
relative rotation and united with the first arm member 11 by
engagement with upper and lower retainer plates 19a and 19b welded
to the upper and lower portions 12a and 11a of second and first arm
members 12 and 11. The retainer plate 19a is slidably engaged at
its lower end portion with a semi-circular upper end of first arm
member 11, while the retainer plate 19b is slidably engaged at its
upper end portion with a semi-circular lower end of second arm
member 12. When the second arm member 12 has been coupled at its
lower portion 12a with the upper portion 11a of first arm member 11
as shown in FIGS. 1 and 2, the slide pawls 13, 14 and cam element
15 are contained in the circular recess 12d of second arm member
12. In such a condition, the hinge pin 17 is inserted into the
central hole 12c of second arm member 12 across the central hole
11c of first arm member 11 and the elongated lateral hole 15a of
cam element 15. In this instance, the radial projection 17a of
hinge pin 17 is engaged with the recess 15d of cam element 15.
[0036] As shown in FIG. 3, a support plate 19c is riveted to the
upper portion 11a of first arm member 11 and engaged with a stepped
portion of hinge pin 17 to retain the hinge pin 17 in position. As
shown in FIG. 1, the support plate 19c is formed with a pair of
hooks 19d. The torsion spring 16 is engaged at its inner end with
an outer end portion of hinge pin 17 and at its other end with one
of the hooks 19d to bias the hinge pin 17 in a counterclockwise
direction so that the cam element 15 is retained at a central
portion of lateral guide groove 11e as shown in FIG. 6(a). The
operation lever 18 is fixed to the outer end of hinge pin 17.
[0037] In a condition where the cam element 15 is retained at the
central portion of lateral guide groove 11e under the load of
torsion spring 16 as shown in FIG. 6(a), the tapered projections
13c, 14c of slide pawls 13, 14 are maintained in engagement with
the opposite flat surfaces of cam element 15 such that the slide
pawls 13 and 14 are maintained in engagement with the semi-circular
ratchet portions 12e of second arm member 12 to restrict relative
rotation of the second arm member 12 with respect to the first arm
member 11. Thus, the back rest of the vehicle seat is retained at
an inclined angle. When the operation level 18 is operated to
rotate the hinge pin 17 against the load of torsion spring 16 in a
clockwise direction, the cam element 15 is moved rightward as shown
by an arrow in FIG. 6(a). The rightward movement of cam element 15
is restricted by abutment of the cam element 15 against the hinge
pin 17 at the left-hand end of lateral hole 15a.
[0038] As a result, the tapered projections 13c, 14c of slide pawls
13, 14 are brought into engagement with the recesses 15b, 15c of
cam element 15 to disengage the slide pawls 13, 14 from the ratchet
portions 12e of second arm member 12 as shown in FIG. 6(c). While
the operation lever 18 is retained in its operated position, the
slide pawls 13, 14 are retained in their disengaged positions from
the ratchet portions 12e of second arm member 12 to permit
adjustment of the inclined angle of the back rest.
[0039] When the operation lever 18 is released after adjustment of
the back rest, the hinge pin 17 is rotated under the load of
torsion spring 16 in the counterclockwise direction to move the cam
element 15 leftward as shown by an arrow in FIG. 6(c). During
leftward movement of the cam element 15, the tapered projections
13c, 14c of slide pawls 13, 14 are disengaged from the recesses
15b, 15c of cam element 15 and brought into engagement with the
opposite flat surfaces of cam element 15 to engage the slide pawls
13, 14 with the ratchet portions 12e of second arm member 12 and to
maintain the slide pawls 13, 14 in engagement with the ratchet
portions 12e of second arm member 12. In such a condition, each
pair of spaced projections 13c, 14c of slide pawls 13, 14 engaged
with the opposite flat surfaces of cam element 15 is useful to
firmly maintain the slide pawls 13, 14 in engagement with the
ratchet portions 12e of second arm member 12 even if the reclining
mechanism is applied with a load. As in the reclining mechanism,
the hinge pin 17 is assembled across the elongated lateral hole 15a
of cam element 15 and engaged at its radial projection 17a with the
recess 15d of the elongated lateral hole 15a, the lateral movement
of cam element 15 is smoothly effected by rotation of the hinge pin
17.
[0040] Illustrated in FIGS. 7 and 8(a)-8(c) is a first modification
of the reclining mechanism shown in FIGS. 1 to 3. In this
modification, a cam plate 21 is assembled with the cam element 15
to move the slide pawls 13, 14 toward and away from the ratchet
portions 12e of second arm member 12 in accordance with lateral
movement of the cam element 15. As shown in FIG. 8(b), the cam
plate 21 is in the form of a rectangular plate 21a formed at its
opposite sides with a pair of arm portions 21b and formed with a
pair of vertically spaced cam slots 21c. The cam plate 21 is fixed
to the cam element 15 at its both arm portions 21b for movement
therewith. The cam slots 21c each are formed with an inclined
portion and a horizontal portion. The slide pawls 13, 14 are
provided thereon with cam pins 13d, 14d which are slidably engaged
with the cam slots 21c of cam plate 21.
[0041] In a condition where the spaced projections 13c, 14c of
slide pawls 13, 14 are maintained in engagement with the opposite
flat surfaces of cam element 15 as shown in FIG. 8(a), the slide
pawls 13, 14 are maintained in engagement with the ratchet portions
12e of second arm member 12, and the cam pins 13d, 14d are located
in the horizontal portions of cam slots 21c. When the operation
level 18 is operated by the user to move the cam element 15
rightward as shown by an arrow in FIG. 8(a), the spaced projections
13c, 14c of slide pawls 13, 14 are brought into engagement with the
recesses 15b, 15c of cam element 15, and the cam plate 21 is moved
rightward with the cam element 15. As a result, the cam pins 13d,
14d are moved toward the cam element 15 by engagement with the
inclined portions of cam slots 21c to disengage the slide pawls 13,
14 from the ratchet portions 12e of second arm member 12. When the
operation lever 18 is released to move the cam element 15 leftward
under the load of torsion spring 16 as shown by an arrow in FIG.
8(c), the spaced projections 13c, 14c of slide pawls 13, 14 are
disengaged from the recesses 15b, 15c of cam element 15 and brought
into engagement with the opposite flat surfaces of cam element 15
to engage the slide pawls 13, 14 with the ratchet portions 12e of
second arm member 12, while the cam plate 21 is moved leftward with
the cam element 15 so that the cam pins 13d, 14d are located in the
horizontal portions of cam slots 21c.
[0042] Illustrated in FIGS. 9(a)-9(c) is a second modification of
the reclining mechanism shown FIGS. 1 to 3. In this modification, a
movable cam plate 22 is assembled with the cam element 15 to move
the slide pawls 13, 14 toward and away from the the ratchet
portions 12e of second arm member 12 in accordance with lateral
movement of the cam element 15. As shown in FIGS. 10(a) and 10(b),
the cam element 15 is provided thereon with a pair of diametrically
opposed support pins 15e, 15f for engagement with the cam plate 22.
As shown in FIGS. 11(a) and 11(b), the cam plate 22 is formed at
its central portion with a square hole 22a and formed with a pair
of diametrically opposed semi-circular cam slots 22b and 22c. The
cam plate 22 is further formed with a circular hole 22d for
engagement with the support pin 15e of cam element 15 and a
semi-circular elongated hole 22e which is slidably coupled with the
support pin 15f of cam element 15 to permit rotation of the cam
plate 22 relative to the cam plate 15. The cam plate 22 is
assembled with the hinge pin 17 at its square hole 22a for rotation
therewith and coupled with the support pins 15e, 15f of cam element
15 at its circular hole 22d and semi-circular elongated hole 22e.
As shown in FIG. 9(b), the slide pawls 13, 14 are provided thereon
with cam pins 13d, 14d which are slidably engaged with the cam
slots 22b, 22c of cam plate 22.
[0043] In the reclining mechanism, the cam plate 22 is rotated with
the hinge pin 17 to cause lateral movement of the cam element 15 in
a direction perpendicular to the slide pawls 13 and 14. In a
condition where the spaced projections 13c, 14c of slide pawls 13,
14 are maintained in engagement with the opposite flat surfaces of
cam element 15 as shown in FIG. 9(a), the slide pawls 13, 14a are
maintained in engagement with the ratchet portions 12e of second
arm member 12. When the operation lever 18 is operated by the user
against the load of torsion spring 16 to rotate the cam plate 22 in
a clockwise direction, the cam element 15 is moved rightward by
thrust force applied at its support pin 15e from the cam plate 22
as shown by an arrow in FIG. 9(a), while the spaced projections
13c, 14c of slide pawls 13, 14 are brought into engagement with the
recesses 15b, 15c of cam element 15. As a result, the cam pins 13d,
14d of slide pawls 13, 14 are moved toward the cam element 15 by
engagement with the cam slots 22b, 22c of cam plate 22 to disengage
the slide pawls 13, 14 from the ratchet portions 12e of second arm
member 12. When the operation lever 18 is released-to rotate the
hinge pin 17 under the load of torsion spring 36 in the
counterclockwise direction, the cam plate 22 is rotated with the
hinge pin 17 to move the cam element 15 leftward as shown an arrow
in FIG. 9(c). As a result, the spaced projections 13c, 14c of slide
pawls 13, 14 are disengaged from the recesses 15b, 15c of cam
element 15 and brought into engagement with the opposite flat
surfaces of cam element 15 to engage the slide pawls 13, 14 with
the ratchet portions 12e of second arm member 12.
[0044] Illustrated in FIGS. 12(a)-12(b) and 14 is a third
modification of the reclining mechanism shown in FIGS. 1 to 3,
wherein the first arm member 11 is replaced with a first disk
member 31 for attachment to the frame structure of the seat cushion
and a second disk member 32 for attachment to the frame structure
of the back rest. The first disk member 31 has a circular recess
31a and vertical and lateral guide grooves 31b, 31c formed in the
circular recess 31a. The second disk member 32 has a circular
recess 32a formed at its inner periphery with a pair of
diametrically opposed ratchet portions 32b.
[0045] The second disk member 32 is coupled within the circular
recess 31a of first disk member 31 for relative rotation in such a
manner that a radial projection 32c of second disk member 32 is
located in a semi-circular recess 31d formed in the inner periphery
of circular recess 31a of first disk member 31. The radial
projection 32c of second disk member 32 is provided to restrict
rotation of the second disk member 32 relative to the first disk
member 31 by engagement with a stepped end of the semi-circular
recess 31d. As shown in FIG. 13, the first and second disk members
31 and 32 are united with each other by means of an annular bracket
39a coupled therewith. The slide pawls 13, 14 and cam element 15 in
the reclining mechanism shown in FIGS. 1 to 3 are replaced with
slide pawls 33, 34 and cam element 35 which are contained in a
space defined by the circular recesses 31a and 32a of disk members
31 and 32. The slide pawls 33, 34 are slidably coupled within the
vertical guide groove 31b of first disk member 31, while the cam
element 35 is slidably coupled within the lateral guide groove 31c
and interposed between the slide pawls 33 and 34.
[0046] The slide pawl 33 is formed at its outer end with a
semi-circular toothed portion and at its inner end with a pair of
tapered projections 33a and a recessed portion 33b between the
tapered projections 33a. Similarly, the slide pawl 34 is formed at
its outer end with a semi-circular toothed portion and at its inner
end with a pair of tapered projections 34a and a recessed portion
34b between the tapered projections 34a. The cam element 35 is
formed at its opposite flat surfaces with each pair of laterally
spaced recesses 35a, 35b and a pair of radially spaced projections
35c, 35d each of which is located between the recesses 35a and
between the recesses 35b. In a condition where the slide pawls 33,
34 are engaged with the opposite flat surfaces of cam element 35 at
their tapered projections 33a, 34a and maintained in engagement
with the ratchet portions 32b of second disk member 32 as shown in
FIG. 12(a), the radial projections 35c, 35d of cam element 35 are
disengaged from the recesses 33b, 34b of slide pawls 33, 34. When
the cam element 35 is moved rightward, the radial projections 35c,
35d of cam element 35 are brought into engagement with the recesses
33b, 34b of slide pawls 33, 34 as shown in FIG. 12(b) to disengage
the slide pawls 33, 34 from the ratchet portions 32b of second disk
member 32.
[0047] For connection of a hinge pin 37 with the cam element 35, a
hinge pin 37 is integrally formed with a connecting arm 37a which
is located in an aperture 35e formed in the cam element 35 and
engaged with an inner periphery of the aperture 35e. As shown in
FIGS. 13 and 34, the hinge pin 37 is assembled with the disk
members 31, 32 in such a manner as to permit rotation of the second
disk member 32 relative to the first disk member 31 and loaded by a
torsion spring 36 in a counterclockwise direction. When the hinge
pin 37 is rotated by an operation level (not shown) against the
load of torsion spring 36 in a clockwise direction, the cam element
35 is moved rightward by engagement with the connecting arm 37a of
hinge pin 37. When the operation level is released to rotate the
hinge pin 37 in the counterclockwise direction under the load of
torsion spring 36, the cam element 35 is moved leftward by
engagement with the connecting arm 37a of hinge pin 37. In FIG. 13,
the reference numeral 39b designates the frame structure of the
seat cushion, and the reference numeral 39c designates the from
structure of the back rest.
[0048] In a condition where the spaced projections 33a, 34a are
maintained in engagement with the opposite flat surfaces of cam
element 35, the slide pawls 33, 34 are maintained in engagement
with the ratchet portions 32b of second disk member 32 to retain
the back reset at an adjusted angle. When the operation lever is
operated to rotate the hinge pin 37 against the load of torsion
spring 36 in the clockwise direction, the cam element 35 is moved
rightward by engagement with the connecting arm 37a of hinge pin
37, while the spaced projections 33a, 34a of slide pawls 33, 34 are
brought into engagement with the spaced recesses 35a, 35b of cam
element 35. During rightward movement of the cam element 35, the
slide pawls 33, 34 are moved toward the cam element 35 by
engagement with the projections 35c, 35d of cam element 35 at their
recessed portions 33b, 34b and disengaged from the ratchet portions
32b of second disk member 32. When the operation leve is released
to rotate the hinge pin 37 in the counterclockwise direction under
the load of torsion spring 36, the cam element 35 is moved leftward
by engagement with the connecting arm 37a of hinge pin 37, and the
spaced projections 33a, 34a of slide pawls 33, 34 are disengaged
from the recesses 35a, 35b of cam element 35 and brought into
engagement with the opposite flat surfaces of cam element 35 to
engage the slide pawls 33, 34 with the ratchet portions 32b of
second disk member 32.
[0049] As in the reclining mechanism, the radial projection 32c of
second disk member 32 is provided to restrict relative rotation of
the second disk member 32 to the first disk member 31 by engagement
therewith, the adjustment of the inclined angle of the back rest
can be restricted in a predetermined extent in a simple
construction.
[0050] Illustrated in FIG. 15 is a modification of the reclining
mechanism shown in FIGS. 1 to 3. The modified reclining mechanism
is composed of the same component parts as the disk members 31, 32,
slide pawls 33, 34 and cam element 35 in the reclining mechanism
shown in FIGS. 13 and 14. In this modification, the hinge pin 37 is
in the form of a longitudinal connecting rod, and the connecting
arm 37a of cam element 37 is replaced with an arm portion 37b2
which is integrally formed with a sleeve 37b1 splined to the
connecting rod 37 for rotation therewith. The arm portion 37b2 of
sleeve 37b1 is engaged with the inner periphery of aperture 35e of
cam element 35 as shown in FIG. 12(a). The torsion spring 36 is
disposed between the first disk member 31 and the arm portion 37b2
of sleeve 37b1 and assembled with the sleeve 37b1 to bias the
connecting rod 37 in a counterclockwise direction. The connecting
rod 37 can be adapted to operatively connect a pair of laterally
spaced reclining mechanisms (not shown) mounted to opposite sides
of a vehicle seat in a simple construction.
* * * * *