U.S. patent application number 11/112517 was filed with the patent office on 2006-07-27 for synchronizing mechanism.
This patent application is currently assigned to Bock 1 GmbH & Co. KG. Invention is credited to Hermann Bock.
Application Number | 20060163925 11/112517 |
Document ID | / |
Family ID | 42269986 |
Filed Date | 2006-07-27 |
United States Patent
Application |
20060163925 |
Kind Code |
A1 |
Bock; Hermann |
July 27, 2006 |
Synchronizing mechanism
Abstract
A synchronizing mechanism for the correlated movement of the
seat and backrest assembly of an office chair has a basic carrier
capable of being positioned on the chair upright, a seat carrier
and a backrest carrier. The backrest carrier is capable of pivoting
about a transverse shaft and is connected directly in an
articulated fashion both to the basic carrier and to the rear end
area of the seat carrier such that a pivoting movement of the
backrest in a rearward direction induces a lowering movement in the
rearward area of the seat carrier. The seat carrier is connected in
an articulated fashion to the basic carrier such that a horizontal
sliding movement towards the rear is superimposed on the lowering
movement of the seat carrier. Through the direct linking of the
backrest carrier to the basic carrier and the seat carrier, it is
possible to simplify the construction.
Inventors: |
Bock; Hermann; (Pyrbaum,
DE) |
Correspondence
Address: |
LERNER GREENBERG STEMER LLP
P O BOX 2480
HOLLYWOOD
FL
33022-2480
US
|
Assignee: |
Bock 1 GmbH & Co. KG
|
Family ID: |
42269986 |
Appl. No.: |
11/112517 |
Filed: |
April 22, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60646279 |
Jan 24, 2005 |
|
|
|
Current U.S.
Class: |
297/340 |
Current CPC
Class: |
A47C 1/03255 20130101;
A47C 1/03277 20130101; A47C 1/03238 20130101; A47C 1/03266
20130101; A47C 1/03294 20130101; A47C 1/03272 20130101; A47C
1/03274 20180801 |
Class at
Publication: |
297/340 |
International
Class: |
A47C 1/02 20060101
A47C001/02 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 24, 2005 |
DE |
10 2005 003 383.0 |
Claims
1. A synchronizing mechanism for correlating a movement of a seat
and a backrest assembly of an office chair, the synchronizing
mechanism comprising: a seat carrier having a rear end area; a
first transverse shaft; a basic carrier capable of being positioned
on the office chair upright; a backrest carrier capable of pivoting
about said transverse shaft and connected directly in an
articulated fashion to said basic carrier and to said rear end area
of said seat carrier such that a pivoting movement of said backrest
carrier in a rearward direction will induce a lowering movement in
said rear end area of said seat carrier; and a second transverse
shaft; said seat carrier capable of pivoting about said second
transverse shaft and connected directly to said basic carrier in an
articulated fashion such that a horizontal sliding movement towards
a rear being superimposed during the lowering movement of said seat
carrier.
2. The synchronizing mechanism according to claim 1, wherein in a
basic position of the synchronizing mechanism, a ratio of a
horizontal component of an articulation distance to a vertical
component of the articulation distance lies between 0.6 and
1.7.
3. The synchronizing mechanism according to claim 1, wherein in a
maximum rearward-pivoted position of the synchronizing mechanism, a
ratio of a horizontal component of an articulation distance to a
vertical component of the articulation distance lies between 2.8
and 5.8.
4. The synchronizing mechanism according to claim 3, wherein in the
maximum rearward-pivoted position, a ratio of a lowering angle of
said seat carrier to a pivoting angle of said backrest carrier lies
between 1:2.1 and 1:3.0.
5. The synchronizing mechanism according to claim 1, further
comprising a rotary sliding articulation, said seat carrier having
a front end area connected to said basic carrier through said
rotary sliding articulation.
6. The synchronizing mechanism according to claim 1: wherein said
seat carrier has a front end area; and further comprising a locking
mechanism provided in said front end area of said seat carrier for
locking a position of said seat carrier in relation to said basic
carrier.
7. The synchronizing mechanism according to claim 1, wherein said
seat carrier has a spring counterpart; and further comprising a
spring configuration for pre-tensioning the synchronizing
mechanism, said spring configuration containing a leg spring with a
leg abutting against said spring counterpart disposed on said seat
carrier such that a position of an articulation point, and thus a
spring characteristic of said leg spring, being varied in
conjunction with the pivoting of said backrest carrier.
8. The synchronizing mechanism according to claim 7, wherein: said
basic carrier has an adjustment mechanism with a worm gear for
actuating said adjustment mechanism; and said leg spring having a
further leg supported on said adjustment mechanism in said basic
carrier.
9. The synchronizing mechanism according to claim 1, wherein said
seat carrier is a seat.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims the benefit under 35 U.S.C.
.sctn.119 (e), of copending U.S. Provisional Application No.
60/646,279, filed Jan. 24, 2005; this application also claims the
priority, under 35 U.S.C. .sctn.119, of German patent application
No. 10 2005 003 383.0, filed Jan. 24, 2005; the prior applications
are herewith incorporated by reference in their entirety.
BACKGROUND OF THE INVENTION
Field of the Invention
[0002] The invention relates to a synchronizing mechanism for the
correlated movement of a seat and backrest assembly of an office
chair. The synchronizing mechanism has a basic carrier capable of
being positioned on a chair upright, a seat or seat carrier and a
backrest carrier.
[0003] The designation "synchronizing mechanism" is understood to
denote assemblies in the substructure of the seat of an office
chair, which assemblies ensure an interconnected kinematic effect
with an associated specific relative movement of the seat and the
backrest in relation to one another. Positioned for this purpose on
a chair upright is a basic carrier, on which are mounted on the one
hand a seat carrier, capable of pivoting about a transverse shaft
and attached to the basic carrier in an articulated fashion, and on
the other hand a backrest carrier, similarly capable of pivoting
about a transverse shaft and attached to the basic carrier in an
articulated fashion. The seat of the office chair, which is
provided as a general rule with an upholstered seat surface, is
mounted on the seat carrier. The backrest carrier, which usually
extends rearwards from the actual synchronizing mechanism, carries
the backrest of the office chair on an upward-extending
bracket.
[0004] The seat carrier and the backrest carrier are connected
together in an articulated fashion in such a way that a pivoting
movement of the backrest in a rearward direction as may be brought
about, for example, by the action of the user of the chair leaning
against the backrest will induce a lowering movement of the rear
edge of the seat in a downward direction. This correlated movement
of the seat and backrest assembly is associated with a significant
comfort-related benefit and is desirable for orthopedic
reasons.
[0005] A synchronizing mechanism of this kind was previously
disclosed in published, non-prosecuted German patent application DE
101 25 994 A1 (corresponding to U.S. Pat. No. 6,675,774). The seat
carrier in this case is connected to the basic carrier via a
linkage arrangement having a complicated configuration in the form
of a four-bar chain. A comparatively large pivoting angle for the
backrest is achieved in this way. Furthermore, a comparatively
large lowering movement of the seat surface is also achieved
through this solution, including at a relatively large pivoting
angle of the backrest, as the seat carrier and the backrest carrier
are pivotally mounted at several points on the basic carrier.
SUMMARY OF THE INVENTION
[0006] It is accordingly an object of the invention to provide a
synchronizing mechanism that overcomes the above-mentioned
disadvantages of the prior art devices of this general type, which
is simple to construct.
[0007] With the foregoing and other objects in view there is
provided, in accordance with the invention, a synchronizing
mechanism for correlating a movement of a seat and a backrest
assembly of an office chair. The synchronizing mechanism contains a
seat carrier having a rear end area, a first transverse shaft, a
basic carrier capable of being positioned on the office chair
upright, and a backrest carrier capable of pivoting about the
transverse shaft and is connected directly in an articulated
fashion to the basic carrier and to the rear end area of the seat
carrier such that a pivoting movement of the backrest carrier in a
rearward direction will induce a lowering movement in the rear end
area of the seat carrier. The seat carrier is capable of pivoting
about a second transverse shaft and is connected directly to the
basic carrier in an articulated fashion such that a horizontal
sliding movement towards a rear is superimposed during the lowering
movement of the seat carrier.
[0008] According to the invention, the backrest carrier, which is
pivotally mounted about a transverse shaft, is connected directly
in an articulated fashion both to the basic carrier and to the rear
end area of the seat or the seat carrier, so that a pivoting
movement of the backrest towards the rear induces a lowering
movement of the rearward areas of the seat carrier. In addition,
the seat or the seat carrier, which is similarly pivotally mounted
about a transverse shaft, is also connected to the basic carrier in
an articulated fashion, so that a horizontal sliding movement
towards the rear is superimposed on the lowering movement of the
seat carrier. Through the direct linking of the backrest carrier to
the basic carrier and the seat or the seat carrier, it is possible
to simplify the construction of the synchronizing mechanism
significantly. A complicated linkage configuration, for example in
the form of a four-bar chain, can now be dispensed with.
Nevertheless, thanks to the configuration of the synchronizing
mechanism in accordance with the invention, the achievable seating
comfort is comparable with that of the synchronizing mechanism of a
more complicated construction. A configuration in which a ratio of
a horizontal component of an articulation distance to a vertical
component of the articulation distance lies between 0.6 and 1.7 has
been found to be advantageous. A ratio of between 1.0 and 1.2 is
particularly advantageous. It has been found to be advantageous, in
addition, if the ratio of the horizontal component of the
articulation distance to the vertical component of the articulation
distance lies between 2.8 and 5.8 in the maximum rearward-pivoted
position. A ratio of between 3.5 and 3.9 is particularly
advantageous. It is also of advantage, furthermore, if the ratio of
a lowering angle of the seat or the seat carrier to a pivoting
angle of the backrest carrier lies between 1:2.1 and 1:3.0 in the
maximum rearward-pivoted position. A ratio of between 2.5 and 2.7
is particularly advantageous. These embodiments permit the
particularly comfortable pivoting of the seat.
[0009] It is also particularly advantageous, furthermore, if the
connection of the seat or the seat carrier to the basic carrier is
effected via a rotary sliding articulation. The horizontal sliding
movement of the seat or the seat carrier towards the rear can thus
be achieved in a particularly easy and robust fashion.
[0010] In a further advantageous embodiment of the invention, a
stop mechanism disposed in the front area of the seat is provided
for locking the position of the seat carrier relative to the basic
carrier. The operating convenience of the synchronizing mechanism
is further increased in this way. Where intermediate stages are
provided for the locking function, the seat can be fixed in a
simple manner in various inclined positions.
[0011] Automatic variation of the "resistance to pivoting" of the
backrest is possible if a spring configuration is provided for
pre-tensioning the synchronizing mechanism, in conjunction with
which the spring configuration contains a leg spring, one leg of
which abuts against a counterpart disposed on the seat or the seat
carrier in such a way that the position of the articulation point,
and thus the spring characteristic of the leg spring, is varied in
conjunction with the pivoting of the backrest. Particularly light
setting of the pre-tensioning of the synchronizing mechanism is
possible, finally, if a worm gear is provided for actuation of an
adjustment mechanism for the leg spring.
[0012] Other features which are considered as characteristic for
the invention are set forth in the appended claims.
[0013] Although the invention is illustrated and described herein
as embodied in a synchronizing mechanism, it is nevertheless not
intended to be limited to the details shown, since various
modifications and structural changes may be made therein without
departing from the spirit of the invention and within the scope and
range of equivalents of the claims.
[0014] The construction and method of operation of the invention,
however, together with additional objects and advantages thereof
will be best understood from the following description of specific
embodiments when read in connection with the accompanying
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] FIG. 1 is a diagrammatic, side view of a synchronizing
mechanism in a basic position according to invention;
[0016] FIG. 2 is a diagrammatic, side view of the synchronizing
mechanism in a position pivoted rearwards to its maximum
extent;
[0017] FIG. 3 is a diagrammatic, front view of the synchronizing
mechanism;
[0018] FIG. 4 is a diagrammatic, sectional view taken along the
line IV-IV shown in FIG. 3;
[0019] FIG. 5 is a diagrammatic, sectional view taken along the
line V-V shown in FIG. 3;
[0020] FIG. 6 is a diagrammatic, sectional view taken along the
line VI-VI shown in FIG. 1; and
[0021] FIG. 7 is a diagrammatic, sectional view taken along the
line VII-VII shown in FIG. 1.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0022] Referring now to the figures of the drawing in detail and
first, particularly, to FIG. 1 thereof, there is shown a
synchronizing mechanism 1 having a basic carrier 2, which is
located at an upper end of a chair upright by use of a conical seat
3, as also represented in published, non-prosecuted German patent
application DE 101 25 944 A1 (corresponding to U.S. patent
publication No. 2002/0171276 A1). The synchronizing mechanism 1 is
formed of a frame-shaped seat carrier 4 and a backrest carrier 5
that is stirrup-shaped in plan view, the side pieces 6, 7 of which
are disposed to either side of the basic carrier 2.
[0023] A seat is provided with a non-illustrated upholstered seat
surface and is mounted on the seat carrier 4. Guide elements 9 with
a T-shaped cross section, which are used for the longitudinal
displacement of the seat, are disposed for this purpose on an upper
side 8 of the seat carrier 4. It is also possible, of course, to
use a seat that is rigidly connected to the seat carrier 4. If a
seat that is capable of displacement relative to the seat carrier 4
is used, the position of the seat can be adjusted at the factory in
a simple fashion by changing the position of the guide elements 9
on the seat carrier 4, and in a particularly simple fashion, for
example, by screwing the guide elements in a different position on
the seat carrier 4. A number of locking projections 11 disposed one
after the other in the longitudinal direction L of the chair are
provided on a lateral frame elements 10 of the seat carrier 4,
which locking projections also serve for the positioning and
attachment of the seat on the seat carrier 4 in a previously
disclosed fashion that is not explained here in any greater
detail.
[0024] Attached to the backrest carrier 5 is a backrest, not
represented here in any greater detail, which is capable of
vertical adjustment in modern office chairs. The backrest can also
be attached to the backrest carrier 5 in a single piece.
[0025] As is shown particularly clearly in FIG. 3, the entire
synchronizing mechanism 1 is constructed with axial symmetry with
regard to a central longitudinal plane M, which affects the actual
kinematics. In this respect, it should be assumed that pairs of
structural elements present on both sides of the actual
synchronizing mechanism 1 are always intended in the following
description.
[0026] On the one hand, the backrest carrier 5 is attached in an
articulated fashion directly to the basic carrier 2 by the lower,
forward-facing end 12 of the side piece 6. In the illustrative
embodiment, the forward-facing or lower end 12 of the side piece 6
is mounted on a pivot bearing 13 on the basic carrier 2 in such a
way that the backrest carrier 5 is articulated directly via the
pivot bearing 13 more or less centrally on the basic carrier 2. In
this way, the backrest carrier 5 can be caused to pivot with the
backrest in the direction of pivoting S about a pivot shaft 14
running through the pivot bearing 13. An additional connecting
element, for example an intermediate articulation between the
backrest carrier 5 and the basic carrier 2, is not provided.
[0027] On the other hand, the backrest carrier 5 is attached to an
upper end 15 of the side piece 6 via an articulation 16 to the seat
carrier 4 in its rear end area 17. By causing the backrest to
pivot, the seat carrier 4 is also carried in the direction of
pivoting S and is lowered. In other words, pivoting takes place
about a pivot shaft 19 of the articulation 16.
[0028] With the backrest carrier 5 in the basic position shown in
FIG. 1, a longitudinal axis 18 of the pivoting mechanism passing
through the articulation points 13, 16 runs at a steeply
rearward-inclined angle. In the basic position, the ratio of a
horizontal component x of an articulation distance A to a vertical
component y of the articulation distance A is of the order of 1.1.
The longitudinal axis 18 in this case includes an angle W1 of
rather more than 40.degree. with a plane E of the seat carrier
lying substantially horizontally in the basic position.
[0029] In a maximum, rearward-pivoted position, the linkage is
inclined even further to the rear; see FIG. 2. The ratio of the
horizontal component x of the articulation distance A to the
vertical component y of the articulation distance A is then of the
order of 3.7. An angle W2 between the longitudinal axis 18 and the
plane E of the seat carrier is less than 26.degree..
[0030] Because of the geometry of the pivoting mechanism, which is
determined essentially by the articulation distance A and the angle
W between the longitudinal axis 18 and the plane E of the backrest,
a transmission ratio of approximately 1:2.6 is achieved in the
maximum, rearward-pivoted position.
[0031] Therefore, for a lowering angle of the seat carrier 4 of
approximately 10.degree., the backrest carrier 5 will be caused to
pivot rearwards thorough a pivot angle of approximately 26.degree.;
see FIG. 2. The geometry that is used has the advantage that a
large lowering angle of the seat carrier 4 can be achieved without
the pivot angle of the backrest having to be too large, which would
lead to a position resembling a reclining position. The so-called
"shirt-pulling-out effect" is also effectively avoided in this
way.
[0032] The front view represented in FIG. 3 illustrates
schematically the position of the sectioned views. Both a section
(FIG. 5) along the central plane M and a further section (FIG. 4)
along a laterally displaced plane running parallel with the plane M
are shown.
[0033] As illustrated in FIG. 4, the seat carrier 4 is connected in
its front end area 21 to the basic carrier 2 via a rotary sliding
articulation 22. The sliding articulation contains a sliding
element 23 connected to the seat carrier 4, which sliding element
23 engages in a slideway formed by two sliding blocks 24, 25
disposed at a mutual distance from one another, which sliding
blocks 24, 25 securely attached to the basic carrier 2. In the
basic position illustrated here, the upper sliding block 25 makes
contact with a stop 26 on the seat carrier 4. The seat carrier 4 is
prevented in this way from executing a pivoting movement in a
forward direction extending beyond the substantially horizontal
basic position. Both of the sliding blocks 24, 25 exhibit globular
guide surfaces 27, which permit the sliding element 23, and with it
also the seat carrier 4 connected to the sliding element 23, to
accompany the pivoting movement rearwards and downwards. The
sliding element 23, which is executed in the form of a rail, in
other words travels with its upper side 28 and its under side 29
along the guide surfaces 27 of the upper and lower sliding blocks
24, 25, in conjunction with which the sliding element 23 is guided
reliably in any desired pivoting position between the upper and the
lower sliding blocks 24, 25. This form of articulation can, of
course, also be replaced by other types of articulation. The rotary
sliding articulation described in published, non-prosecuted German
patent application DE 101 25 994 A1 can be used, for example.
[0034] Because of the form of the backrest carrier 5 and its
arrangement on the basic carrier 2 and the seat carrier 4, and when
the backrest is subjected to loading, the backrest carrier 5
executes on the one hand a pivoting movement in the direction of
pivoting S towards the rear and downwards. However, the pivoting
movement also causes the seat carrier 4 both to be pivoted both
towards the rear and downwards, and to be displaced horizontally
rearwards in the area of the rotary sliding articulation 22. This
does not produce any relevant lifting movement at the front end of
the seat surface, as a result of which constrictions on the under
side of the upper leg are avoided.
[0035] Compared with the solutions previously familiar from the
state of the art, a pivoting mechanism of particularly simple
construction is proposed in accordance with the invention.
Manufacturing costs are reduced on the one hand in this way. On the
other hand, the so-called "shirt-pulling-out effect" is also
significantly reduced in this way, in spite of the simple
configuration. To put it another way, particularly high seating
comfort is achieved, but without having to resort to complicated
and costly solutions.
[0036] In addition, the position of the seat carrier 4 in relation
to the basic carrier 2 can be locked by a locking mechanism 30 in
the area of the front end 21 of the seat carrier 4. The locking
mechanism 30 contains, on the one hand, locking grooves 32 disposed
one after the other in the longitudinal direction L on the under
side 31 of the seat carrier 4, and, on the other hand, an
substantially cuboid-shaped locking key 33 disposed in the basic
carrier 2, which key is executed to engage in the locking grooves
32. The locking key 33 is guided in a guide channel 34 and is
attached at its lower end to a wire spring 35, which is capable of
being actuated via a pivot lever 36 in a manner not represented
here in any greater detail. In the locked position, the locking key
33 is pretensioned by the wire spring 35 in the direction of the
locking groove 32, so that secure engagement in the locking groove
32 is assured. By actuation of the pivot lever 36, the wire spring
35 is caused to move downwards, as a consequence of which the
active return of the locking key 33 from the locked position takes
place. A free end of the locking key exhibits a key end 37 with a
mushroom-shaped cross section, by which it engages in the locking
groove 32. The chamfered contact surfaces of the key end 37 also
ensure secure locking in the locking groove 32 when the seat
carrier 4 is caused to pivot.
[0037] A plurality of locking grooves 32 disposed one after the
other in the longitudinal direction L are provided. The
synchronizing mechanism can accordingly be secured in various
intermediate positions between the basic position and the maximum,
rearward-pivoted position. The operating lever 38 disposed opposite
the pivot lever 36 is used to release the vertical adjustment of
the chair upright.
[0038] The synchronizing mechanism 1 is pre-tensioned against the
direction of pivoting S that is to say towards the basic position
of the synchronizing mechanism 1. A spring configuration is
provided in the form of two leg springs 41 capable of alignment
with one another in a transverse direction; see FIG. 7. The leg
springs 41, 41' are positioned around the pivot shaft 14. An
upward-facing leg 42 is supported against a projection on the seat
carrier 4, whereas a second, forward-facing leg 43 is supported on
an adjuster mechanism in the basic carrier 2. The leg springs 41,
41' exert a spring force against the rearward-directed pivoting
movement of the backrest, which is variable through the adjuster
mechanism by actuation by a crank lever 44.
[0039] The adjustment mechanism contains a worm 46 connected via a
shaft 45 to the crank lever 44, in conjunction with which the shaft
45 lies in bearing shells 47 in the basic carrier 2; see FIG. 6.
The crank lever 44 is disposed in the sleeve-shaped pivot lever 38
for the release of the gas spring and is pulled out for actuation
of the worm gear. The worm 46 engages with its teeth in a worm gear
48, which is connected to a threaded rod 49. The threaded rod 49 is
mounted at both of its ends 52, 53 so that it is capable of
rotating on the one hand in a cover 50 of the basic carrier 2 and
on the other hand in a basic body 51 of the basic carrier 2. By
actuation of the crank lever 44, the worm gear 48 is caused to
rotate by the worm 46, and a guide prism 54 serving as a bearing
for the spring leg is guided along the threaded rod 52 by the
movement of the threaded rod 52. If the guide prism 54 is moved
downwards, the forward-facing spring leg 43 of the leg spring 41 is
acted upon and is forced downwards, which leads to an increase in
the pre-tensioning of the leg spring 41. The consequence of this is
that the pivoting movement of the seat carrier 4 and the backrest
carrier 5 takes place in the direction of pivoting S against a
greater resistance.
[0040] The upward-facing second leg 42 of the leg spring 41 makes
contact with a second guide prism 55, which is disposed on the
under side 31 of the seat carrier 4. In other words, the leg spring
41 is supported in a floating fashion on both sides. In the event
of the pivoting of the seat carrier 4 rearwards and downwards, that
is to say in the direction of pivoting S, the point of articulation
of the upper spring leg 42 is displaced. The position of the point
of articulation accordingly changes when a load is placed on the
backrest in such a way that the point of articulation is displaced
in the direction of the mid point 56 of the spring. The result of
this is an automatic change in the spring behavior of the leg
spring 41 in the event of a movement in the direction of pivoting
S. To put it another way, in the event of pivoting of the seat, the
leg spring 41, and thus the seat as a whole, automatically become
harder.
[0041] The backrest carrier 5 is secured to the central pivot shaft
14 with fixing screws 57. During the pivoting movement, the pivot
shaft 14 in other words rotates together with the backrest carrier
5. The diameter of the pivot shaft 14 is selected so that the leg
springs 41, 41' do not lie on the pivot shaft 14 in the tensioned
position. The internal diameter of the leg springs 41, 41' is at
all times greater than the diameter of the pivot shaft 14.
Unobstructed rotation of the pivot shaft 14 is assured in this way
in conjunction with pivoting of the seat. In addition, disturbing
contact noises such as creaking are avoided. However, since both of
the leg springs 41, 41' applied to the pivot shaft 14 lie with
their periphery in a spring support 58 in the form of a prism, the
positioning of the leg springs 41, 41' in their operating position
is still reliably assured.
[0042] The use of leg springs 41, 41' permits the direct
transmission of the spring force to the synchronizing mechanism 1,
so that additional component parts are not required for the
transmission of the force. The total number of component parts
required is also smaller, when compared to the synchronizing
mechanisms that are already familiar from the state of the art,
since the adjusting mechanism is constructed from relatively few
component parts. The adjusting mechanism is particularly robust,
furthermore, due to the use of the worm drive, and because of its
very high transmission ratio, it permits the particularly light
adjustment of the crank lever.
[0043] An alternative embodiment (not shown here) provides for the
seat carrier 4 to be integrated into the seat shell of the seat. In
other words, the seat shell of the seat is executed in such a way
that it is connected directly to the basic carrier 2. A separate
seat carrier is then no longer necessary. The manufacturing costs
can be further reduced in this way. Alongside the reduction in the
required number of component parts, a reduction in the overall
height is also possible. A more delicate form is imparted to the
seat in this way. The backrest carrier 5 is attached in an
articulated fashion directly to the rear end of the seat shell, and
the basic carrier 2 is similarly connected to the front end of the
seat shell via a sliding bearing or the like. The seat shell
exhibits two pivot bearings to accommodate the pivot shaft 14. The
sliding element 23 is also a component part of the seat shell. The
pivot bearings and the sliding element 23 are preferably also an
integral part of the seat shell. The seat shell similarly exhibits
the locking grooves 32 necessary for the locking mechanism.
* * * * *