U.S. patent number 3,602,537 [Application Number 04/793,282] was granted by the patent office on 1971-08-31 for seat system with a backrest.
Invention is credited to Fritz Kerstholt, Gerdi Kerstholt.
United States Patent |
3,602,537 |
Kerstholt , et al. |
August 31, 1971 |
SEAT SYSTEM WITH A BACKREST
Abstract
A seat system comprising a backrest, a seat, means adapted to
pivot said seat about a horizontal axis positioned in a base, means
to attach said backrest to the supporting element for said seat by
means of a hinged connection, a base, a spring means, said backrest
being connected with said base by at least one said spring means,
and means to arrange said seat system so that, when a load acts
upon said seat system, said means simultaneously produces in a
stabilizing manner a forwardly directed compressive force on said
backrest being adapted to the user, and a supporting force against
the supporting element of said seat.
Inventors: |
Kerstholt; Gerdi (6291
Philippstein, DT), Kerstholt; Fritz (6291
Philippstein, DT) |
Family
ID: |
41668894 |
Appl.
No.: |
04/793,282 |
Filed: |
January 23, 1969 |
Foreign Application Priority Data
|
|
|
|
|
Feb 1, 1968 [DT] |
|
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K 60 154/34 |
|
Current U.S.
Class: |
297/300.5;
297/316; 297/300.7; 297/303.4; 297/300.8 |
Current CPC
Class: |
A47C
1/03272 (20130101); E04H 6/06 (20130101); A47C
1/03294 (20130101); A47C 1/03238 (20130101); A47C
1/03277 (20130101); F16C 11/10 (20130101) |
Current International
Class: |
A47C
7/44 (20060101); A47C 7/40 (20060101); A47C
1/026 (20060101); A47C 1/022 (20060101); A47C
1/024 (20060101); F16C 11/10 (20060101); F16C
11/04 (20060101); E04H 6/06 (20060101); A47c
003/00 () |
Field of
Search: |
;297/316,304,305,337 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Machado; Reinaldo P.
Claims
We claim:
1. A seat system such as for school children to enforce a good
sitting posture comprising a seat member;
a backrest member;
a base;
a spring means;
means connecting said backrest with said seat member;
said spring means mounted to engage said backrest at the point of
connection spaced from the point of contact between said seat
member with said backrest;
means to move said seat member and said backrest relative to each
other independently from each other;
said spring member connected with said base to provide a bearing
force for the said seat and a forwardly directed stabilizing
pressure upon the said backrest, when the seat is occupied;
means to limit the movements of said seat member;
means to adjust the spring tension of said spring means to the
weight of the user;
means to lock at least one point of support of said spring means at
varying positions;
means to lock the seat in varying positions;
means to lock the backrest in varying positions;
means to displace the seat member in a horizontal direction;
means to displace the seat member in the vertical direction;
a depository means laterally secured to the said seat member
exposed for use independently of the respective angle of incidence
of said seat member;
and
means to enable the occupier of the seat to maintain his back at
all times in contact with the said backrest, independently of the
position of said seat member, whereby an improper sitting posture
will cause discomfort to the sitter and force him to adopt a
correct sitting position.
2. A seat system comprising a backrest member;
a seat member;
a base;
a horizontal axis mounted in said base;
means to pivot said seat member forwardly and rearwardly abut said
axis;
means connecting said backrest with said seat member; at least one
spring means;
said spring means mounted to engage the said backrest at a point of
connection spaced from the point of contact between said seat
member and said backrest;
said means to pivot and said spring means arranged to move said
seat member and said backrest relative to each other;
said backrest being connected with said base by said spring
means;
said means connecting said base with said seat member in such a
manner that, when a load acts upon said seat member, said spring
means simultaneously produces a stabilizing forwardly directed
compressive force on said backrest to adapt it to the position of
the user and a bearing force against the said seat member.
3. Seat system according to claim 1, characterized in that said
spring means includes a telescopic shock absorber arrangement.
4. Seat system according to claim 1, characterized in that said
spring means comprises at least one flat spring.
5. Seat system according to claim 1, characterized in that means
are provided for varying the height of said seat and further means
for adapting the action of said spring means to the different
heights of said seat.
6. Seat system according to claim 1, characterized in that disposed
ahead of said seat is a support being displaceable with respect to
height and/or depth of said seat, and in that means are provided
for locking said support in different positions.
7. Seat system according to claim 2, characterized in that the
portion of said backrest coming into contact with the back of the
user is variable in the relative position thereof with respect to
said seat, in that means are provided for locking the same in the
various positions, and in that said locking means are adapted to be
rendered operative and/or inoperative by means of a handle.
8. Seat system according to claim 2, characterized in that a pair
of rosette-type cover members with lateral serrations is
coordinated to at least one of said butt straps and in that said
butt strap is guided in a recess of one of said rosettes.
9. Seat system according to claim 2, characterized in that at least
one of the points of application of said spring means is
displaceable when a corresponding locking means is disengaged.
10. A seat system as claimed in claim 1, said point of connection
of said spring means with said backrest being spaced below said
point of contact of said seat member with said backrest.
11. A seat system as claimed in claim 1, said point of connection
of said spring means with said backrest being spaced above said
point of contact of said seat member with said backrest.
12. A seat system as claimed in claim 1, said means to connect said
backrest with said seat member being hinge means.
13. A seat system as claimed in claim 1, said backrest member
including an extension thereof with which said spring means
engage.
14. Seat system according to claim 1, characterized in that means
are provided for locking said seat and/or said backrest in
different positions.
15. Seat system according to claim 7, characterized in that said
means are butt straps being provided with apertures.
16. Seat system according to claim 15, characterized in that at
least one of said butt straps additionally comprises a tooth
construction into which a toothed locking member is adapted to
engage.
17. Seat system according to claim 7, characterized in that at
least two such means are simultaneously provided which are adapted
to be rendered operative and inoperative by means of a common
handle.
18. Seat system according to claim 9, characterized in that elastic
means act upon said handle in such a manner that the locking means
can be rendered inoperative only against the action of a spring
force.
19. Seat system according to claim 7, characterized in that several
of said means are simultaneously provide and are adapted to be
rendered operative and inoperative by means of at least two handles
preferably acting independently of each other.
20. Seat system according to claim 1, characterized in that said
seat is positioned displaceably in the horizontal direction.
21. Seat system according to claim 13, characterized in that the
supporting element for said seat is displaceably positioned.
Description
DESCRIPTION OF THE PRIOR ART
Known in the prior art are seat systems in which the backrest is
rigidly secured to the supporting element of the seat. This is the
case, for example, in the well-known chairs.
The seat is defined as, and also hereinafter understood to be, the
geometrical surface which comes into contact with the user; in
other words, the surface of the upholstered seat in an armchair,
the surface of the seat board in a chair, etc.
Also known in the art are seat systems in which the backrest is
variable in its angular position with respect to the seat. When
such a seat system is used for an armchair, the backrest is secured
by means of hinges to the rear edge of the frame supporting the
upholstered seat superstructure. This frame is displaceably
positioned in the base. Depending upon the direction of
displacement, the backrest adjusts to a flatter or steeper
position. Another seat system of this type is the well-known office
chair whose backrest consists of a flat spring with a pivotally
mounted wooden backrest. The backrest wood is provided so as to be
displaceable in height, and the flat spring, engaging with its
lower end to a greater or lesser degree under the seat, may be
clamped thereto.
Moreover it is no longer new is seat systems to provide the
supporting element for the seat and the backrest as a rigid unit
which is secured to a base with the aid of a spring means acting
upon the supporting element. By virtue of this means, the user can
recline the seat more or less markedly. In so doing, he must brace
himself against the floor and exert a certain compressive force
during the reclined spatial condition so that the seat remains in
that position. The application of this force becomes tiresome after
already a relatively short period of time. Very soon the user will
therefore return the seat system to the normal position in which
the seat is almost horizontal and the application of pressure is no
longer necessary. Such seat systems are thus not suited to allow
the user a prolonged stay in a position of rest in which the
backrest is strongly reclined from its normal position.
The known seat systems further have the disadvantage that they do
not adjust automatically to the respective sitting position of the
user. As a result thereof, the known seat system is not adapted in
the best possible manner to the user's respective sitting position
since, as is well known, the user changes his position while using
the seat system. This is found to be uncomfortable, when sitting,
in the long run.
BACKGROUND OF THE INVENTION
Field Of The Invention
The present invention relates to a seat system with a backrest
which does not have the disadvantages and drawbacks outlined
hereinabove.
SUMMARY OF THE INVENTION
Among the objects of the present invention are the following: The
seat system proposed by the present invention is intended to adapt
automatically to the respective sitting position of the user.
Furthermore, a relative position of the seat system which is in
conformity with the body of the user and a good support for the
back of the user are to be assured at all times. This applies
particularly to the three known essential sitting positions, namely
the writing position in which the upper part of the body leans
forwardly, the upright sitting position, and the rearwardly
reclined listening position.
The aforementioned objects are obtained with a set with a backrest,
wherein the seat is pivotable about a horizontal axis positioned in
a base and wherein the backrest is secured to the supporting
element for the seat preferably by means of a hinged connection.
The seat system proposed by the present invention is characterized
in that the backrest is in operative connection with the base or
the floor by way of at least one spring means, this means and the
points of application thereof being so chosen that, under a load,
this means simultaneously produces in a stabilizing manner a
forwardly directed compressive force on said backrest, which force
is adapted to the user, and a supporting force against the
supporting element of the seat. The novel seat system may also be
so constructed that the upper part of the system including the
supporting element for the set and the backrest being rigidly
secured to the latter is in operative connection with the base or
the floor by way of at least one spring means, this means and the
points of application thereof being so chosen that, under a load,
this means simultaneously produces in a stabilizing manner a
forwardly directed compressive force on said backrest, which force
is adapted to the user, and a supporting force against the
supporting element of the seat. Means may be provided for
delimiting the movements of the seat. Means for adjusting the
spring tension, or elastic force, to the weight of the user may
also be provided. It is further possible to provide means for
locking the seat and/or the back rest in different positions
thereof. These means may be butt straps being equipped with
apertures. When several of such means are present simultaneously,
they may be adapted to be rendered operative and inoperative by
means of at least one common handle. Elastic means may be provided
which act upon the handle and allow for rendering the locking means
inoperative only against the action of a elastic force. The seat
may be disposed displaceably in the horizontal direction. A support
may be positioned there ahead which is displaceable with regard to
height and/or depth of the seat, means being provided for locking
the support in variable positions. Moreover, one of the points of
application of the spring means may be displaceably positioned.
The advantage of the novel seat system according to the present
invention resides in that the user can lie or lean against the
backrest at all times and independently of the respective angle of
incidence of the seat. It has been found that the user is supported
in his respective sitting position independently of whether the
seat is inclined forwardly, horizontal, or reclined toward the
rear. Damages to the posture of the user, which can occur easily
particularly in the case of persons having a sedentary occupation,
are thereby effectively eliminated. A sitting only on the front
edge of the seat, as it is observed oftentimes in the case of
typing personnel, is no longer readily possible since the seat will
in that case adjust to its extreme inclined position and
additionally become so steep and sloping toward the front that this
sitting position is found to be definitely uncomfortable. For the
reasons set forth above, the novel seat system is particularly
suitable also for children because they will be made to sit
properly at all times by virtue of the peculiar construction of the
seat system. For school children it is advantageous to provide an
attachment or deposit which is laterally secured to the supporting
element for the seat and allows for having, for example, a book bag
handy at all times, independently of the respective angle of
incidence of the seat itself.
BRIEF DESCRIPTION OF THE DRAWINGS
Other objects and many of the attendant advantages of this
invention will be readily appreciated as the same becomes better
understood by reference to the following detailed drawings in which
like reference numerals designate like of equivalent parts
throughout the figures thereof and wherein
FIGS. 1 to 10 inclusive depict embodiments and details thereof,
which provide a linkage connection for the backrest and the seat
support;
FIG. 1 is a cross-sectional view of an embodiment of the
invention;
FIGS. 2a and 2b are variations of details of FIG. 1;
FIGS. 3, 4 and 5 are cross-sectional views of other variations of
details of FIG. 1;
FIG. 6 depicts a principle of the invention common to the above
variations as applied to seats in engine-operated vehicles and the
like;
FIG. 7 is a cross-sectional view of a variation of a detail of FIG.
1;
FIGS. 8a and 8b depict details of variations of FIG. 1;
FIGS. 9 and 10 are schematic showings of elements of the invention
in cross section;
FIGS. 11 and 12 depict details in cross section and in perspective,
respectively, which can be incorporated into or substituted for the
elements of the previous figures to provide a fixed connection
between the seat support and the backrest.
In the seat system illustrated in FIG. 1, the frame 10 serving as
supporting element for the seat board or support 10' is pivotally
positioned about an axle 11 in a base. This base consists
essentially of two U-shaped tubes 12 which are reinforced by means
of struts or crossbars 15 and connected with each other by means of
rods 13, 14 and 16. The backrest is secured to the frame 10 by
means of a hinged or linkage connection 17. This backrest consists
of a frame 18 and of a backrest leaf 19 being secured to the latter
by means of a hinge or link 20. The frame 18 includes a crossbar
21. Accommodated between this crossbar 21 and the rod 16 is a
telescopic shock absorber means. It consists of the rod-shaped and,
respectively, sleeve-shaped structural elements 22, 23 which are
rotatably positioned at the rods, adapted to be slid into each
other and supported against each other by means of a spring 24. The
rod 23 is provided, at the lower end thereof, with a thread with
which a nut 23' is guided. The latter serves for making it possible
to vary the tension of the spring. At the height of the hinged
connection 17, a butt strap 25 is rotatably mounted at the frame
10. This strap is guided in an eye 26 which has been shown in cross
section in the drawing and which is secured to the sleeve 22. The
butt strap 25 includes apertures 28 as well as two stops 27. The
latter delimit the possible movements of the frame 10. The
apertures 28 in connection with corresponding apertures in the
sleeve 22 as well as the rod 23 allow for locking the seat in a
desired position by means of a pin 29 which is inserted into one of
these apertures.
The seat system according to the invention operates in such a
manner that, when the pin 29 is pulled out, the back of the user is
at all times in contact with the backrest independently of the
position of the seat or seat support. This applies also when the
user has shifted his sitting position on the seat forwardly. When
only the front edge of the seat is actually weighted or loaded, the
latter will set itself to such a markedly forwardly inclined
position that this particular setting feels uncomfortable to the
user. He will therefore improve his sitting position by shifting
his weight on to the entire seat.
According to a modified embodiment, the seat plate 10' proper can
be provided with eyes enclosing the axle 11 and, at the rear edge
thereof, with the hinged connection to the backrest so that the
frame 10 can be omitted. In this case, the plate 10' itself is the
supporting element for the seat support.
FIG. 2a shows the same arrangement of the frame 10, the seat plate
10', the backrest 18 and the spring means 22, 23, 24, 23'. The axle
11, however, is secured in this instance to an upright-type base
and the spring means is supported against one of the transverse
brackets of this base. In addition thereto, a deposit or attachment
30 which is made of round iron, for example, may be mounted at the
frame 10. Since this deposit or attachment is rigidly secured to
the frame 10, it will concomitantly execute the movements thereof.
As a result, any material placed thereon, such as a book bag for
example, has at all times the same position with respect to the
user, which the latter will find to be of great help. The
perspective detail shown on the left-hand side illustrates the
configuration of such a deposit or attachment.
FIG. 2b illustrates the arrangement of the frame 10, the seat plate
10', the back rest 18 an the spring means 22, 23, 24, 23' in
connection with an upright-type base in which the upper part of the
seat system is rotatable and the height of the seat, or seat
support, is variable. The axle 11 is secured to a sleeve 74 which
is slipped or put over a center support 75 resting upon a cross
base. Rigidly mounted at the sleeve 74 is an angular member 76 and
the spring means engages at the free-standing angle thereof. During
a displacement of the sleeve 74 along the center support 75 with
the use of well-known means which have therefore not been further
illustrated herein, the coordinated spring tension or elastic force
is maintained in the same manner as when the upper portion of the
seat system is pivoted about the center support.
FIG. 3 illustrates an embodiment of the novel seat system in which
the frame 32 of the backrest projects downwardly beyond the frame
10 and comprises two bends. It is rotatably attached to the frame
10 by means of butt straps 32'. The lower end of the frame 32
extends between the base 12, 13, 14 and is supported thereagainst
by means of a telescopic shock absorber means 33. In place of this
means or in connection therewith, a tension spring 34 may be
employed. For purposes of delimiting the movements of the frame 10
and hence of the seat support, a butt strap 35 is rotatably
positioned at the frame 10 and encloses with the slot thereof a
guide pin 36 being secured to the base. By changing the means 33
and, respectively, the spring 34 to another one of the slots 38,
the elastic force acting upon the back rest may be varied. A buffer
37 serves for delimiting the movements of the backrest.
The seat system shown in FIG. 4 also comprises an upright-type base
with the axle 11 being mounted at the upper end thereof. The frame
40 of the backrest is extended here again to under the seat support
and guided by means of a slot 40' by a bolt attached to the base.
At the lower end thereof, a tension spring 41 engages which is
secured to the upright or stand of the base. The movements of the
frame 10 are delimited by two ropes 42, 43 being attached to the
stand.
FIG. 5 illustrates a seat system in which the backrest is supported
at the base by means of a leaf spring 45. The frame 18 of the
backrest comprises in proximity to the hinged connection 17 a
support 46 which acts as a delimiting means against the frame 10.
The spring 45 is provided at the two ends thereof with one eye or
lug portion each. One lug portion encloses the rod 13 of the base,
the other one encloses the crossbar 21 of the backrest A rod 47
which may be placed into different recesses of the crossbars 48
serves for supporting the spring 45. The action of the spring 45
becomes stronger or weaker depending upon the pair of recesses into
which the rod 47 is placed. It may thus be coordinated to the
weight of the user. Shoulder portions 47' secure the rod 47 in
position in a direction at right angle to the plane of the drawing.
The same means as in the embodiment of FIG. 3 are present for
delimiting the movements of the frame 10. The adjustment of the
elastic force by the different placement of the rod 47 may be
complemented in that the seat support of the seat plate 10' is
displaceably positioned against the supporting element thereof
within the shape of the frame 10, and sliding tubes 10" serve for
this purpose. By varying the seat depth, i.e. by displacing or
shifting the seat proper rearwardly or forwardly, the force of the
spring may be finely matched to the weight of the user. The
respective position of the seat may be fixed by means of a screw,
for example. It is understood that the displacement of the seat
either forwardly or rearwardly may also be carried out in that the
frame 10 is positioned in sliding tubes which are pivotally
positioned on the axle 11. In this case the seat board 10' is
rigidly secured to the frame 10. Such a position of the frame 10 is
schematically illustrated in FIG. 8b.
FIG. 6 illustrates the principle common to all of the embodiments
described hereinbefore used for a seat system for motor vehicles.
Attached to the frame 50 of the seat, which is in this case the
supporting element for the seat support, is the frame 51 of the
backrest via a hinged connection 17. The frame 50 is pivotable
about an axle 11 being mounted in a box-shaped base 52. A leaf
spring 53 supports the back rest. This spring 53 is secured with
one end thereof in the base 52. The other end is provided as
elongated lug portion and encloses a crossbar 54 in the frame 51.
For varying the force of the spring serves a block 56 which is
guided in a slide or rail 57 and which may be manually shifted by
means of a spindle 55. This block 56 comprises a recess through
which the spring 53 extends. The backrest of a motor vehicle seat
should be adapted to be folded forwardly within wide limits. For
this reason the spring 53 comprises a joint being locked in the
clockwise direction which, in connection with the elongated lug
portion at the upper end of the spring, allows for folding the
backrest forwardly. The movements of the frame 50 are delimited by
the specific configuration of the base. Locking means (not shown)
may be provided for retaining the seat system in the adjusted
position once it has been chosen.
It should be noted that the relative positions of the backrests
shown in FIGS. 2a to 6 presuppose already a loaded or weighted
position of the seat system. In he unloaded position thereof, the
back rests are positioned more forwardly, as indicated in FIG.
1.
Variations regarding these illustrations are possible. For example,
in the place of the one spring means respectively shown, two or
more springs may be utilized. The fixing means illustrated have
been chosen as examples since they can be represented in a simple
manner. This manner of representation does not represent, however,
a restriction to the means shown.
It may be advantageous to vary the relative height of the seat
against the floor and hence to adapt it to the height of the user.
An example for such a seat is illustrated in FIG. 7. The seat shown
therein is similar to that of FIG. 1. In this case, however, the
axle 11 comprises one rod-shaped downwardly directed projection 80
each being attached at both ends thereof at right angle. These
projections are slidingly positioned in guide sleeves 81 which are
secured to the base. Different heights of the axle 11 may be
adjusted by means of pins 82. In order to be able to adapt the
spring means to such a height adjustment, the spring means
consisting of telescopically provided rod-shaped and, respectively,
sleeve-shaped structural elements 88, 89 as well as of a supporting
spring 90 includes at the upper end of the sleeve 89 a bore into
which extends a rod 91. This rod 91 encloses with a lug portion
disposed at the upper en thereof the crossbar 21 of the frame parts
83 of the backrest. This frame 83 is connected via a hinged
connection 17 with the frame 10. The rod 91 comprises cross or
transverse bores at different heights, and a holding pin 92 engages
thereinto, securing the relative position between the rod 91 and
the sleeve 89. The elastic force remaining the same, it becomes
possible with the aid of this displaceable rod 91 to adapt the
length of the spring means to a height adjustment of the axle 11
and therewith to a height adjustment of the seat. It may also be
used, however, for varying the tension of the spring 90 and for
adapting it to the weight of the user, the height of the seat
support remaining the same.
While the preceding figures described above disclose embodiments
which allow for a variation of the relative positions of the
different parts of a seat system, the disclosure of FIG. 8a will
now be described hereinafter. In this case, only one handle is used
for locking different parts of the seat system. The axle 11 is
secured to the base and pivotally supports the frame 10 which
represents the supporting element for the seat plate 10' and hence
for the seat support. The backrest is secured to the frame 10 by
means of a hinged connection 17. The backrest consists of upwardly
open bent or formed frame portions 83 and a frame 84 which is
introduced thereinto. Disposed at the latter by means of a joint 20
is a backrest leaf 85. The bent or formed frame portions 83 are
connected with a crossbar 21. Attached to this crossbar is a
telescopic spring means, or telescopic shock absorber means, which
is secured with its lower end to the rod 16 of the base. In
contrast to the preceding figures, this spring arrangement
comprises a second sleeve 88' into which extends the rod 91. A
clamp 95 which is adapted to act upon the sleeve 88' thus fixing
the relative position between the sleeves 88' and 89 is disposed at
the sleeve 89. This clamp may be rendered operative or inoperative
by means of an eccentric mechanism which acts in the longitudinal
direction of a clamping bolt 96; i.e. at right angle to the plane
of the drawing. The handle or means acting on the eccentric
mechanism is here shown to be a lever 97. A hand wheel may also be
used instead. Rigidly secured to the sleeve or bearing of the frame
10 enclosing the axle 11 is a lever 100 and a butt strap 101 is
hingedly connected to the free end thereof. The strap comprises a
slot which is identified with reference numeral 101' and through
which extends the clamping bolt 96 including a pressure plate 96'
When the bolt is tightened, also the butt strap 101 is secured in
position in addition to the actuation of the clamp 95, the frame 10
thus being fixed in its relative position. In an analogous manner,
a butt strap 102 comprising a slot 102' is connected to the hinged
connection 17 and a butt strap 103 with a slot 103' is connected to
the frame 84. The former serves for supporting the action of the
butt strap 101 and effects a division of the load to be absorbed
thereby. The butt strap 103 holds the backrest leaf at the desired
height. All the butt straps are in contact with the one clamping
bolt and may be secured in the respective position by means of the
latter with the aid of only one handle or means 97. Further
possibilities of movement of the seat may be determined, if
desired. Reference is made in this context, for example, to the
movement of the backrest leaf 85 relative to the frame 84, and to
the adjustment relative to the depth of the seat support, as
described hereinabove. For the sake of clarity, the butt straps
necessary therefore have not been shown here but only indicated by
arrows L. The frame 84 may be provided with transverse slots which,
together with pins, allow for the setting of the basic height of
the backrest leaf.
Instead of one handle or actuating means, two such means, as shown
in dotted lines, or more may be provided. In the case of two such
means, it is possible to either subdivide the butt straps into
different groups, in which case one clamping means is coordinated
to each group, or to extend the clamping bolt 96 beyond the
pressure plate 96' and to attach a handle also at that end. This
has the advantage that the seat may be locked from both sides,
which is favorable particularly for wheel chairs.
In order to guarantee at all times a perfect locking action, it may
be advantageous to allow for the actuation of the handle or lever
from the locking position only against the action of a spring Such
a spring 97' thus supports the locking movement of the handle or
lever 97.
A different method for the horizontal displacement of the seat
support is illustrated in FIG. 8b. The frame 10 of the seat is
positioned in sliding sleeves or bearings 104. These sleeves are
rotatably positioned at the base by means of the axle 11, only a
part of the tubes 12 being shown in this figure. The sleeves 104
are interconnected by means of a sleeve enclosing the axle 11.
Rigidly attached to this sleeve is the lever 100. The seat support
10' is rigidly mounted on the frame 10. The respective position of
the seat support with regard to the base may be fixed by means of
the butt strap 102. The remaining parts of the seat system are the
same as shown in FIG. 8a so that they need not be illustrated
again.
When a seat system of the type described herein is installed, for
example, in a construction machine or in a motor vehicle, it must
be adapted to change its relative position to the ground-- viewed
in the sitting direction-- only by a maximum of about 30
centimeters. It may in this case be suitable to support the
telescopic shock absorber means on the ground rather than at the
base. Such a seat is schematically shown in FIG. 9. A base 120 is
displaceably positioned on the ground by means of slide rails 120'
and carries the pivot axle 11 for the supporting element 121 of the
seat support. Mounted to the element 121 by way of a hinged
connection 17 is the frame 122 of the backrest which carries via a
joint 20 a backrest leaf 125 serving as carrier for the backrest
upholstery as indicated. The frame 122 comprises a crossbar 21 on
which engages a telescopic shock absorber means 123. This shock
absorber means is supported against the ground and guided there in
a slide 129. In order to keep the supporting point stable, a butt
strap 128 is connected at the base 120 and engages with the other
end thereof at the spring means, but may be detached therefrom When
this connection is released or disengaged, the base or support of
the spring means can be made to glide forwardly under the seat
support. In this case, the backrest is set as extension of the seat
support so that a reclining seat will result which rests with the
rear end thereof on a support (not shown). The arrangement of the
other butt straps and of the handle or lever corresponds to the
foregoing description and is here indicated only by dotted
lines.
The requirements with regard to stability are particularly great
for seat systems used in this manner. In order to assure an
additional safety, the butt straps 101, 102 may further be provided
with a toothed system, as shown for the butt strap 201 in FIG. 10.
A locking member 130 which is provided with an analogous tooth
construction in as steep a fashion as possible is displaceably
positioned on another but strap 203 intersecting at an angle of
possibly 90.degree., or on a corresponding guide rail being secured
to the telescopic means. This locking member includes a guide bolt
132 engaging in the slot of a disc 133 being coupled with the
handle or lever. The slot consists of a spiral with attached
circular arc. When the locking connection is released, the locking
member 130 is lifted out of the tooth construction of the butt
strap 201 and releases the latter likewise for he longitudinal
displacement. During locking, the spring 97' guides the handle or
lever 97 and thus the disc 133 into a position such that the
serrations of butt strap and locking member already engage
mutually. The greatest portion of the spiral-shaped slot is thereby
traversed. During the retightening by hand, the bolt 132 then
engages in the circular arc-shaped part of the slot and thus
renders it possible that, with the pressure of the teeth within
each other remaining the same, the lateral clamping of the butt
straps by means of the clamping bolt 96 is accomplished.
In all of the embodiments described above, the backrest is
accommodated by means of a hinged connection at the supporting
element for the seat support. The concepts of the invention may
also be used, however, for set systems in which the supporting
element and the backrest are rigidly connected with each other. An
example for such a construction is shown in FIG. 11. In this
figure, the pivot axle 11 is again guided, by means of lateral
projections 80, in sleeves 81 being secured to the base and is
adjustable with respect to its height with the aid of pins 82. The
frame 10 is in operative engagement with the base by way of two
chains 42', 43' which delimit the possibilities of movement
thereof. For a height displacement, the chains are hung
correspondingly longer. The frame 83 of the backrest is rigidly
attached to the frame 10. Inserted in the open ends thereof is the
frame 84 to which the backrest leaf 85 is mounted via a joint 20 A
spring means is disposed between the crossbar 21 of the frame 83
and the rod 16 of the base; it has been shown to be pivoted out
toward the right for the sake of greater clarity of illustration.
It consists of sleeve-shaped elements 88', 89 which are supported
against each other by means of a spring 90. The sleeve 89 comprises
at the upper end thereof a bore through which extends a rod 91 into
the sleeve 88'. This rod encloses with an eye or lug portion the
crossbar 21. The rod 91 further comprises cross bores at different
heights into which meshes a supporting or retaining pin 92, fixing
the relative position between the rod 91 and the sleeve 89. The
lower end of the spring means is supported at the rod 16 of the
base. With the aid of the displaceable rod 91 it is possible to
vary the tension of the spring and to adapt it to the weight of the
user, the height of the axle 11 and hence of the seat support
remaining the same. It also serves, however, for coordinating the
length of the spring means to the height adjustment of the seat
support. The seat support 10' is displaceably positioned on the
frame 10 so that the location of the weight of the user may be
shifted either forwardly or rearwardly by a certain value, which
has the effect of a fine adjustment of the tension of the spring
90. Instead of the means shown, different means may also be used
for varying the elastic force. Reference is made in this connection
to a worm gear, for example, or to a toothed rack with locking
mechanism, or an over sleeve with locking pin. As indicated in
dotted lines, a support 110 may be positioned ahead of the seat
support. It serves with the upholstered surface thereof for
additionally supporting the thighs of the user, which may be of
advantage for instance for handicapped persons. The support 110 is
slidingly positioned at the frame 10. The linkage 115 thereof is
provided with a lockable joint 116 which allows for varying the
support additionally also in the height thereof. Locking of the
support with respect to the frame 10 is accomplished by means of a
butt strap 114 which encloses with the slot thereof the bolt 96 in
the same manner as the butt straps 111, 112 and 113 serving for
locking the seat support as well as of the back rest with regard to
height and angle of incidence. All of the butt straps are locked by
means of the common handle or lever 97 whose action has already
been described hereinabove.
In order to additionally secure the angular position of the butt
straps with respect to the longitudinal axis of the telescopic
spring means, toothed rosettes may be present, as shown as detail
in FIG. 12. A rosette 140 having a spur gearing or radial
serrations is secured to the clamp 95 in such a manner that it
encloses the clamping bolt 96. The counter rosette 141 being
equally provided with a spur gearing is displaceably positioned on
the bolt 96. It includes a recess in which is guided the butt strap
101 to be fixed. A compression spring 142 is added between the two
rosettes. When the lever 97 is actuated for purposes of locking,
the butt strap is moved toward the clamp 95 in the direction of the
bolt. The toothed rosettes intermesh with respect to each other and
fix the angle of incidence of the butt strap relative to the
telescopic shock absorber means. The spring 142 serves for the
purpose of separating the rosettes from each other when the
clamping connection is opened.
It should be understood, of course, that the foregoing disclosure
relates to only preferred embodiments of the invention, that
interchanges of the elements and features described in the several
figures of drawings may be obviously resorted to and that various
modifications are contemplated without departing from the spirit
and scope of the invention as hereinafter defined in the appended
claims.
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