Note: Descriptions are shown in the official language in which they were submitted.
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Load-rel~ arrang _ent
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The present invention relates to a load-relieving arrangement for
use in connect;on with seated or standing work of a kind which
comprises a support element intended to act upon the forearm area
of the user, which support element is capabLe on the one hand of
movement in essentially horizontal directions~ and on the other
hand of movement downwards against the effect of a spring which
fully or partly relieves the weight of the user's arm.
Arrangements of the aforementioned kind are used to reduce the
stress on the musculature, especially in the neck and the
shoulders, due, inter alia, to the weight of the arms, in
conjunction with work involving long periods without movement or
work which requires only small movements of the body, for example
certain types of assembly work or work at a cash reg~ster or a
computer terminal. A previously disclosed arrangement of the
aforementioned kind consists of a sling suspended by means of a
line in a so-called balance block, in which sling at least a part
~0 of the forearm, possibly including an adjacent part of the wrist or
elbow, is supported to a degree which can be determined by
adjustment of the balance block. This previously disclosed
arrangement requires the availability of considerable height and is
rather noticeable~ for which reason its use is found to be
embarrassing by certain individuals, as a result of which there is
a risk of it being used only once damage due to wear and tear~
which it is actually intended to prevent, has already occurred. The
previously disclosed arrangements make use of mechanical springs,
which means that the load-relieving forces exerted by them will
vary depending on the level at which the supported parts of the
user's arm are present at any given time.
One object of the present invention is to propose a novel and
improved load-relieving arrangement of the kind described by way of
introduction "~hich takes up little space and can be executed very
discreetly, so that it can be readily accepted by everybody, and
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which provides a supporting effect which is essentially unaffected
by the arm movements of the user~
For the aforementioned purpose the arrangement in accordance with
the invention is characterized essentially in that the spring is a
pneumatic spring of a kind already familiar from the prior art, in
that the pneumatic spring has a piston~ the maximum stroke volume
of which is neglig;ble in relation to the space containing the gas
providing the spring action, which means that the pneumatic spring
will exert essentially the same spring force irrespective of the
vertical position of the support element, and in that the pressure
of the gas providing the spring action is adjustable by means of an
adjustment device capable of operation by the user.
Further characterizing features and advantages of the invention are
indicated in the subsidiary Claims and can be appreciated from the
following description of an embodiment of the invention shown in
the accompanying drawing, but selected only as an illustrative
example.
Fig. 1 is a partial front view of a chair fitted with a load-
-relieving arrangement in accordance with the invention.
Fig. 2 is a side view on an enlarged scale of the load-relieving
arrangement in accordance with Fig. 1.5 Fig. 3 is a view from the rear of the load-relieving arrangement in
accordance with Fig. 1.
Fig. 4 is an axial sectional view on an enlarged scale through a
lower part of the load-relieving arrangement in accordance
with Figs. 1-3.0 Fig. S is an axial sectional view on an enlarged scale through an
upper part of the load relieving arrangement in accordance
with Figs. 1-3.
Fig. 1 shows a chair with a seat 1, illustrated here in part only,
a leg structure 2 and a backrest 3. Arranged on one side of the
seat is a load-relievino arrangement indicated generally by the
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designation 4~ comprising a support element 5 carried by an upright
assembly consisting of the parts 6 and 7.
The upright assembLy 6, 7 is connected at a considerable distance
beneath the support element S via a universally articulated device
8 to a bracket 9 mounted on the chair at the side of the seat. The
bracket 9 can thus be executed in such a way that the universally
articulated device 8 is capable of being attached to it in
different pos;tions, viewed in the sense of the depth of the seat 1
of the chair. The universally articulated device 8 permits pivoting
of the upright assembly 6, 7 both about a horizontal axis 10, that
is to say forwards and backwards in Fig. 1, and about axes running
essentially perpendicularly to it, that is to say to one side and
the other, as shown by the arrows 11 in Fig. 1~ The universally
articulated device 8 is preferably spring-loaded towards a neutral
position indicated in Fig. 1.
An upright assembly 6, 7 with its associated support element 5 ;s
shown in more detail in Figs. 2-5. The parts 6 and 7 of the upright
assembly are supported in such a way as to be capable of
longitudinal displacement or of telescop;ng relat;ve to one
another, ;n conjunction with which one part 6 exhibits a fastening
lug 12 via which it is secured in a detachable fashion to the
universally articulated device 8 by means of a screw 13. This screw
13 passes through an essentially vertical slot 14 arrranged in the
fastening lug 12, which slot permits the part 6 to be secured to
the universally articulated device 8 at different posit;ons of
height and inclination relative to the chair seat 1.
The upright component 7 and with it the support element 5 are
capable of being displaced downwards against the effect of a
pneumatic spring consisting of a piston 15, which is mounted in a
guide 16 in such a way as to be capable of pivoting and of axial
displacement~ so as to permit movement into a space 17 filled with
the gas providing the spr;ng action, for example air, under
positive pressure. The maximum stroke volume of the piston 15 is
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selected for this purpose so as to be so insignificant in relation
to the space 17 containing the gas providing the spring action that
the pneumatic spring exerts essentially the same spring force
irrespective of the vertical position of the support ele~ent 5.
In the example shown the pneumatic spring piston 15 consists of a
cylindrical, essentially vertical rod, the lower end of which is
rigidly connected via a socket 18 to the lower end of the upright
component 6 executed as a straight tube. The p;ston 15 projects
upwards through the upr;ght component 6 and is mounted in a
gas-tight fashion in the guide 16, which is rigidly attached inside
a lower, straight part of the similarly tubular upright component
7. On pushing down the support element 5~ and with it the upr;ght
component 7, the guide 16 and the lower part of the upright
component 7 surrounding it thus slide downwards on the piston 15
and into the upright component 6. The piston 15 is fitted at a
point close to the socket 18 with a radially projecting pin 19, in
conjunction with which the downward movement of the support element
5 is restricted through the engagement between that pin 19 and the
lower end of the guide 16. Also executed in the lower end of the
guide 10 is an angled groove 20, in which the pin 19 can be
accommodated by pushing down and turning the guide 16, so that it
retains the guide 16, and with it the upright component 7 and the
support element 5, in a detachable fashion in a lower ineffective
position.
There extends diametrically through the upper end of the piston 15
a further pin 21, and a 'U'-shaped recess 22 is executed in the
upper end of the guide. Through its engagement with the upper end
of the guide 16, the pin 21 restricts the extent to which the
upr;ght components 6, 7 can be moved apart by the effect of the
pneumatic spring 15-17, and in so doing determines the uppermost
position of the support element 5~ In this pos;tion the pin 21 has
been displaced to the bottom of the recesss through interaction
with the walls of the 'U'~shaped recess 22. By initially selecting
the rotated position of the p;ston 15 in relat;on to the upr;ght
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component 6, and the rotated position of the guide 16 in relation
to the upright component 7, ;t is accordingly possible to ensure
that the support element 5, when in its initial upper pos;t;on in
which ;t ;s not under any load, ;s always fac;ng ;n the desired
sense, usually parallel with the side edge of the seat 1.
In order to permit working at a certain distance in front of the
edge of a table, the upright component 7 exhibits, as may be
appreciated from Fig. 2, an essentially 'C'-shaped rearward-curved
1~ part 23 ;n the area ;mmed;ately beneath the support element 5. The
support element 5 ;n the embodiment illustrated here is essentially
of 'U'-shaped cross-sect;on and ;s p;vota(ly mounted about a shaft
24 passing across same. The support element 5 benefits from its
small thickness measured in the vertical sense. It ;s s;tuated on
the side of the 'C'-shaped part 23 of the upright component 7
facing towards the user, and its underside is situated level with
or below the top part of the part 23. The element 5 exhibits at its
rear end an upward-inclined base 25 (Fig. 2), such that, by
engaging with the user's elbow, unintent;onal sl;d;ng of the
forearm towards the rear ;s prevented.
In order to achieve the necessary large volume of the space 17 for
~he gas providing the spring action, without this hav;ng a
detr;mental ;nfluence on the appearance of the arrangement, use is
made ;n the illustrat;ve example shown here of the ;nside of the
tubular upright component 7 as the space for the gas provid;ng the
spring effect, which is sealed for this purpose at its oppos;te
ends. For the purpose of sett;ng any desired spring pressure, an
adjuster device is provided in the form of a pump bu;lt into the
upper end of the 'C'-shaped part 23 and a valve 26, 27 (Fig. 5).
The valve comprises a screw 26 capable of being operated by the
user, which screw is installed in a valve pipe 27 running between
the space 17 and the surrounding atmosphere, with a valve orif;ce
capable of being opened and closed by means of the screw 26. The
pump compr;ses a pump p;ston 28 with a handle 29 capable of
operation by the user~ The pump piston 28 is mounted ;n such a way
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as to be capable of axial displacement inside a pump cylinder 20,
nhich communicates w;th the space 17 via a non-return valve 31. The
scope of the invention nevertheless permits the alternative
arrangement of a pressur;zed gas cartridge, for example, in place
of the pump 2&-31.
The invention is thus not restricted to the embodiment described
above and illustrated in the drawing, but can be realized in any
manner within the scope of the idea of invention described in the
Claims. For e~ample, the universally articulated device need not
necessarily spring back into position, but may exhibit a small
amount of inherent friction, so that the upright component 6 will,
in the absence of lateral forces acting on same~ maintain its
direction relative to the chair 1-3, ~hilst the support element 5
and the upright component 7 will change their position relative to
the upright component 6. The load-relieving arrangement can also be
applied to a work table or a work bench~
