Note: Descriptions are shown in the official language in which they were submitted.
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The present invention relates to a body-weight ad~usting
device suitably employed for a seat suspension of a vehicle such as
an automobile etc
A conventional body-weight adjusting device is quite poor
in its operation. In fact, adjusting the height of the seat may be
impossible when the door is closedO
With respect to a seat for an automobile etc., particularly,
a driver's seat, it is, of course, necessary to adjust the position of
the seat back and forth in proportion to the physical make-up of a
driver and it is further necessary to adjust the height of the seat.
Devices capable of making these adjustments to a seat are known.
Hcwever, according to a conventional device, it is impossible to make
the distance between a pair of springs wider and furthermore one must
rotate an adjusting shaft about 16 times by hand for an adjustment
thereof frcm a 50 kg setting to a 100 kg setting. This makes
operation of the device quite difficult. Furthermore, the operational
force becomes greater in proportion to the adjustments up to 100 kg.
As a matter of practice, an adjusting operation thereof is impossible
when the door is closed.
The present invention provides a body-weight adjusting
device for a seat suspension of a vehicle which permits adjustments to
be made easily by means of a control lever similar to a hand brake
usually employed for automobiles.
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According to a first aspect of the invention, a body-weight
adjusting device for a seat suspension comprises a pair of X-shaped
links constituting said seat suspension; a rotary shaft extending in a
transverse direction of said pair of X-shaped links; an operation
lever connected to one end of said rotary shaft in such manner that it
is disposed in a direction substantially perpendicularly to the axis
of said rotary shaft; at least one pinion gear fixed on said rotary
shaft for integral rotation therewith; at least one rack gear,
rotatably fixed to mesh with said pinion gear; at least one tension
spring operatively connected to one end of said X-shaped links and
latched at the other end of said at least one rack qear whereby said
rotary shaft rotated by operation of said operation lever drives said
rack gear and, consequently, said tension spring, to adjust said
X-shaped link.
According to another aspect of the present invention, a
body-weight adjusting device for a seat suspension comprises a
rotation shaft extended in a lateral direction of the seat suspension,
a pair of pinions being fixed to said rotation shaft with a prescribed
distance so as to rotate integrally therewith, a pair of qears
pivotally supported by a fixing portion rotatably free being engaged
with said pinions, one ends of a pair of tension sprinqs being latched
to said gears, the other ends of which being fixed to X-shaped or
parallel links constituting said seat suspension, said latching points
being arranged to be at a position not passing through the dead point
of said springs within the region of a rotating adjustment of the
rotation shaft, a control lever being connected to said rotation shaft
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in a direction perpendicular thereto and a locking means for always
locking the rotation of said rotation shaft and also for unlocking
the locking state of said rotation by the same hand controlling
said control lever depending upon the controlling state of said
control lever.
In the figures,
Figure 1 is a diagrammatic perspective view showing one
emhodiment according to a conventional seat suspension,
Figure 2 is a plan view of one part thereof,
Fi~ure 3 is a perspective view of a main part of a seat
suspension constructed accordinq to the present invention, and
Figure 4 is a sectional view of one part thereof.
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First of all, a convent;onal seat suspenslon will be
described with reference to Figures 1 and 2 -in order to
understand the present invention.
In Figure 1, (1) is an upper frame and (2) is a lower
frame. The lower frame is constructed substantially in the
shape of a square in plan view and each side thereof is composed
of a frame member made of a metal etc. bent substantially in the
shape of a channel. The open side of each channel-shaped frame
is directed inwardly. With respect to the lower frame (2), it
is, of course, posslble to construct same -independently, but it
is also possible to construct same in such a manner that it can
move back and forth by putting it on a slide rail before and
behind a seat.
The upper frame (1) is composed of, as a main
constitutional element thereof, a flat plate portion made of a
metal etc. substantially corresponding to the above-mentioned
shape of the lower frame (2) and the left and right end portions
thereof or the necessary portions of the other ends thereof are
bent downward. As the upper frame (1), the so-called cushion
pan is employed and a seat body (not illustrated) is fixed
thereto.
Furthermore, a pair of X-shaped links (3) at the left
and right sides of the lower frame (2) are mounted thereon. In
each X-shaped link, there are two link bodies (4) and (5)
pivotally connected together by means of a spindle (6) at a
substantially middle portion thereof. An upper end (5a) at the
back side (or the front side thereof) of each X-shaped link (3)
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is rotatably connected to the upper frame ~1) by means of a
spindle (7), and a lower end (4b) thereof is rotatably connected
to the lower frame (2) by means of a shaft (8). A lower end
(5b) at the front side (or the back side) of each X-shaped link
(3) slidably engages the lower frame (2) by means of a roller
(9) etc. so that it is free to move back and forth.
Furthermore, the upper ends (4a) at the front side of the
X-shaped links are joined by means of a frame member (10)
extending therebetween, so as to provide support for the front
portion of the upper frame (1) from the bottom.
Moreover, the upper ends (5a) at the back side of the
X-shaped links (3) are joined to each other by means of a frame
(11) and one end of each of a pair of springs (12) is latched to
the frame 11.
With reference to Figure 2, a bell crank (14) is
rotatably attached to a suitably fixed portion (for example, an
under surface of the upper frame) by means of a spindle (13).
One end of the crank engages a regulating shaft (15) extending
in the lateral direction of the seat suspension and the other
end thereof is connected rotatably to one end of a tension frame
(16) by means of a spindle (17). Furthermore, the tension frame
(16) is rotatably connected to the centre of an equalizer frame
(18) by a spindle (19) and an end of each of a pair of springs
(12) is respectively latched at a respective end of the
equalizer frame (18).
The regulat-ing shaft (15) is constructed, according to
the present embodiment, as a rotating shaft having a thread
groove (20') on one portion thereof so as to engage a nut (21)
therewith. Thus the shaft engages one end of the above-
mentioned bell crank (14) with the nut (21~.
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Moreover, at a substantial middle portion of the
above-mentioned seat suspension, a shock absorder (22) is disposed and
one end thereof is rotatably attached at the back side of the lower
frame (2) and the other end thereof is rotatably connected to the
frame (10).
According to this conventional construction, at the time of
using the seat, i.e. at the time of bottoming thereof, the X-shaped
links (3) are compressed so that the height of the upper frame is
shortened accordingly. However, because the shock absorber (22) is
located at a substantially middle portion of the seat suspension and
the pair of springs (12) are also located in the vicinity of the
middle portion of the seat suspension at an upper part thereof, it is
impossible to make the seat suspension thin on the whole.
The present invention is conceived in order to over come the
above-mentioned defect. Hereinafter, a seat suspension according to
the present invention will be described with reference to Figure 3 and
Figure 4. The same numerical references are used for parts that
correspond to parts in Figure 1 and Fiqure 2.
A seat suspension according to the present invention, as
shown in Figure 3, has a shaft (15) rotatably mounted, a pair of
pinions or pinion gears (25) fixed to said rotary shaft (15) so as to
rotate therewith, a pair of sector gears or rack gears (26) which are
pivotally mounted on a fixed portion. For example, the gears (26) can
be mounted on the under surface of the upper frame (1) by means of
rotation shafts (29). A bearing member (27) can be provided to mount
each shaft (29). One end of each of a pair of tension springs (12) is
operatively connected to the X-shaped links (3) and the other
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end thereof is latched to a latching point (28) of a respective sector
gear or rack gear (26).
The latching points (28) are located so that they do not
pass through the dead point of the springs (12) within the range of
adjustment possible with the rotation shaft (15). Needless to say,
the points (28) could be located on the dead point at one end thereof
within the adjustment range.
Furthermore, a control lever or operation lever (30) is
connected to the rotation shaft (15) and extends in a direction
perpendicular to the shaft. Thus the shaft (15) can be rotated by
raising or lowering the control lever.
In this case, it is possible to arrange the control lever in
such a way that the tension in the springs (12) is a minimum when the
lever is raised somewhat above the horizontal (a slight angle in
relation to a horizontal direction) and so that the tension in the
springs (12) is a maximum when the lever is raised above the
aforementioned level. (For example, the lever is rotated 108
degrees).
According to the present invention, a braking mechanism, i.e.
a locking means (31), for the rotation shaft (15) is mounted as shown in
Figure 3. Since the locking means (31) is known, detailed description
thereof will be omitted. The locking means (31) can be unlocked by
pulling an unlocking lever (32) that extends substantially parallel to
the control lever (30). The lever (32) is drawn towards the lever
(30) by the same hand that is controlling the lever (30) and while
this hand is controlling the lever (30). However, the construction of
the locking means is not limited to the above described means.
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With this described arrangement, it is possible to
unlock the locking means (31) and to rotate the rotation shaft
(15) by contolling the control lever (30). Each of the pair of
pinions (25) rotates with the shaft and the tension of the
springs (12) changes in accordance with the rotation of the
sector gears (26) as is clear from Figure 4. Accordingly the
height of a seat may be adjusted in proportion to the body-
weight of a passenger sitting -in the seat.
When the adjustment is stopped at a selected point,
the rotation shaft (15) will not rotate further owing to
automatic locking by the locking means (31). Also, this may be
effected by merely raising or lowering the control lever (30),
which can give an excellent control thereof. Further the above
control operation may be effected while sitting on the seat even
when the door is closed. Moreover, adjustment can be carried
out even with a comparatively small force by employing a longer
control lever (30).
