Note: Descriptions are shown in the official language in which they were submitted.
A TELESCOPIC STAY
The present invention relates to a telescopic stay for
supporting two objects which are capable of being folded
relative to one another, and particularl`y, although not
exclusively, for supporting a work surface which can be
folded relative to a frame structure.
In the case of foldable w~rk surfaces which are supported
in their raised positions by means of some suitable form
of stay, it is desirable that the stay will enable the
work surface to be locked readily and reliably in its
raised position, and to be readily released from said
locked position prior to lowering the work surface. The
stay must also be capable of locking the raised work
surface reliably and to form a firm support for the work
surface in the desired working position thereof.
A telescopic stay which fulfils these desiderata to a
large extent is known from the British Patent Specifica-
- tion No. 1 524 281 and comprises two tubes which can be
displaced telescopically in relation to one another and
the mutually opposite ends of which are each pivotally
connected to a respective one of said two objects, and
further comprises an inner guide tube arranged within the
telescopic tubes, a tension spring which extends axially
through all tubes, and locking means for releasably
locking the telescopic tubes in a given working position
relative to one another.
This known stay, however, is encumbered, inter alia,
with a number of disadvantages. When the telescopic
tubes are retracted one within the other, the inner guide
tube projects beyond the ends of the telescopic tubes,
thereby preventing the stay from being fitted directly
to a complete surface, e.g. a wall. Instead it is
necessary to fit the stay to a surface which is lateral-
ly of~set, so that the inner guide tube can be permitted
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to project out fxom the telescopic tube.
When stays of this parti'cular kind are intended, inter
alia, to support tables or work 'surfaces in watercraft,
caravans and in other connections where relative movement
of the aforesaid two objects can occur, it is essential
that the stay is capable of preventin~ the work surface
from swinging, or of damping 'such swinging movement,
when the work surface occupies its collapsed or lowered
positionO Since, when the known stay is retracted, the
aforesaid inner guide tube projects from the outer tele-
scopic tube, the tension spring has no damping effect
whatsoever on the swinging movement of the foldable work
surface, unless the work surface swings to such an extent
as to cause a stop provided on the inner guide tube to
engage the outer telescopic tube. Consequently, small
swinging movements are not damped at all.
The main object of the inve~tion is to provide an impro-
ved stay of the aforedescribed kind in which, inter alia,
the aforesaid drawbacks are no longer found. In order to
enable the stay to be fitted directly to a wall or
correspondin~ surface it is essential that the inner
guide tube will not project from the telescopic tubes
in any position of the tubes. Furthermore, the tension
spring shall constantly draw the telescopic tubes to-
gether, so as to dampen the swinging motion of, for
example, a work 'surface in its downwardly folded position.
Accordingly, a stay according to the invention is charac-
terized in that the innex guide tube is fixed axially
in relation to one of the telescopic tubes and accompa-
nies the tube in its axial movement relative to the
other of said tubes, and in that each end of the tension
spring is fixed in relation to its respective telescopic
tube, the length of the tension spring being such that
the spring will constantly exert on the telescopic tubes
a force which strives to draw said tubes together.
3 ~ ~r~
With a stay of this construction the inner guide tube
will not protrude beyond the telescopic tubes, and the
stay is effective for damping even small relative swing-
ing movements between the mutually hinged objects to
which the stay is fitted, the extent to which damping is
achieved being dependent on the force exerted by the
tension spring.
In order to permit different reltive working positions
between the two objects the outer surface of the outer
one of the two telescopic tubes is preferably provided
with circumferential shoulders adapted to cooperate with
a pivotally mounted locking arm. To this end the outer
telescopic tube is preferably made up of several coaxial
tubes placed one within the other, each of which tubes
protrudes from the immediate outer tube such that the
end surface of each tube forms one engagement shoulder
for the locking arm.
Preferably, the locking arm is pivotally mounted at one
end of the arm which end may have the form of a sleeve
which embraces the inner telescopic tube. A spring can
therewith be mounted between the inner telescopic tube and
the sleeve-shaped part of the arm to constantly bias the
arm towards its locking position.
In a preferred embodiment of the stay, each of the outer
ends of respective telescopic tubes is secured to a
respective mounting means by ineans of a pivot having the
form of a peg which extends diametrically through respec-
tive tubes. The inner guide tube can therewith be fixed
axially in relation to the outer telescopic tube with the
aid of the peg passing through said tube, and the pivotal-
ly mounted locking arm can be pivoted around the peg
passing diametrically through the inner telescopic tube.
In order to facilitate fitting of the stay to the afore-
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. .
said objects, each of the said mounting means preEerablyincludes a pair of angle pieces the respective one legs
of which are located opposite one another on mutually
different sides of respective telescopic tubes and are
provided with holes for receiving an associated peg.
Simple and reliable mounting of the tension spring is
achieved by securing one end of the spring to the peg
passing through the inner telescopic tube and by hooking
the other end of the spring firmly to the end of the inner
guide tube connected to the other peg.
The invention will now be described in more detail with
reference to the accompanying drawings.
Figure 1 illustrates a stay according to the invention in
the supporting position of said stay.
Figure 2 is a bottom plan view of part of the stay illu-
strated in Figure 1.
Figure 3 illustrates the stay of Figure 1 in its retrac-
ted state.
Figure 4 illustrates a modified stay according to Figure
1 designed to permit three different working positions.
Figure 5~ illustrates the operation of the stay of Figure 4.
In Figure 1 the reference numeral 1 identifies a work sur-
face which is hinged to a stationary or fixed surface 2
by means of a hinge 3. In order to hold the work surface 1
in a horizontal work position flush with the fixed sur-
face 2, a stay 4 according to the invention is mounted
between the work surface 1 and a support frame structure 5,
which may consist, for example, of a table frame, a wall
or some corresponding structure.
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The stay 4 includes an outer telescopic tube 6 and an
inner telescopic tube 7, which are arranged to slide
axially one within the other. Arranged within the outer
telescopic tube 6 is an inner reinforcing guide tube 8,
which also extends into the inner telescopic tuhe 7. The
reference numeral 9 identifies a locking arm, one end 10
of ~hich is sleeve-shaped and embraces the inner tube 7,
and the other end of which is cupped or half-cylindrical
in shape and presents a bevelled end surface which in its
locking position engages beneath a correspondingly bevel~
led end surface on the outer tube 6 for locking co-action
therewith.
The inner telescopic tube 7 is pivotally connected to the
work surface 1 by means of a pivot ha~ing the form of a
hollow, tubular peg 11 which passes diametrically through
the tube 7 and the sleeve-like end 10 of the locking arm 9,
between two mutually opposing flanges 12 on a mounting
arrangment which includes an angle piece located on each
side of the sleeve-shaped end 10. The outer telescopic
tube 6 i similarly pivo-tally mounted by means of a pivot
in the form of a peg l3 which is fitted in two mutually
opposing flanges 14 and extends diametrically through the
tube 6 and the guide tube 8. The angle pieces with the
flanges 12 are screwed to the undersurface of the work
surface 1.
A tension spring 15, which for the sake of simplicity
have been shown in full lines, extends axially through
all of the tubes and is attached at one end to the peg 11
and at the other end is firmly hooked over one end of the
inner guide tube 8. In the active supporting state of
the stay illustrated in Figure 1, the spring 15 is
extended and strives therefor to draw the two telescopic
tubes 6 and 7 together. In the illustrated state of the
stay, however, the tubes are prevented from being re-
tracted one within the other by the locking arm 9, which
i5 in locking engagement (full lines) with the outer
telescopic tube 6. The locking arm is biased towards
its locking position by means of a bias spring 16, which
acts between the inner telescopic tube 7 and the sleeve-
shaped part 10 of the locking arm.
Unintentional release of the locking arm 9 is also pre-
vented through the engagement of the free, bevelled end
of the locking arm with the undersurface of the corre-
spondingly bevelled edge of the outer tube 6, this locking
1Q engagement being maintained in the illustrated position
also through the weight of the work surface 1 acting on
the arm.
Figure 2 is a bottom plan view of the right-hand end o~
the stay 4 illustrated in Figure 1 and the associated
mounting means.
It will be seen from Figure 2 that, among other things,
the free end of the Iocking arm 9 has the form of a slot-
ted tube or sleeve of the same diameter as the sleeve-
shaped end 10. The end o the part 9 is also bevelled so
that its outer surface coincides substantially with the
outer surface of the outer tube 6 with which the locking
arm is intended to cooperate. This means that engagement
of the bevelled end surface of the locking arm 9 with the
end surface of the telescopic tube 6 takes place over a
relatively large peripheral arcuate surface, thereby
avoiding the drawback of the puncti~orm contact between
the mutually engaging surfaces and also the subsequent
elevated wear thereon which would result from such contact.
In order to enable the locking arm 9 to swing freely,
to some slight extent, to the position shown in chain
lines in Figure 1, the diameter of the sleeve-shaped part
10 of the arm must be greater than that of the telescopic
tube 7, so as to provide sufficient space for such move-
ment to take place.
The through-passing peg 11 is firmly riveted or swaged
in holes provided in the outwardly projecting legs 12
of the angle pieces 17, vide Figure 2. The same applies
to the tubular peg 13 at the other end of the stay. The
open ends of the tubular pegs are clc~sed with hc~ogenous
plastic plugs.
Figure 3 illustrates the work sur~ace 1 with the stay 4
in a retracted state. The length of the tension spring
15 is such that the spring is still slightly stretched
when the work surface occupies its lowered position, so
that the spring will exert a damping effect on undesired
swinging movement of the downwardly folded work surface.
The desired damping effect can be obtained with the aid
of a spring of suitable spring rating.
It will be seen from Figures 2 and 3 that no parts project
fro~n the telescopic tubes 6 and 7 when collapsing the work
surface 1, which facilitates fitting of the stay to the
aforesaid two objects and allows the stay to be used in
connections in which, in many cases, the previously
known stays could not be used or could only be used with
great difficulty. The aforedescribed stay operates in
the following manner.
In th~ collapsed position of the work sur~ace 1, illustra-
ted in ~igure 3, the telescopic tubes 6 and 7 of the stay
are withdrawn one inside the other. In this position o~
the ~tay the locking arm 9 is biased towards the outer
surfa~e of the telescopic tube 6 by means of the spriny
16. As bcforementioned, the tension spring 15 ls also
uncler some tension in this position of the stay.
When the work surface is ~wung upwardly on the hlnge 3,
the telescoplc tube 7 wlll be progresslvely extended from
khe telescopic tube 6. When the position illustrated in
chain lines in E'igure 1 is reached, the free end of the
loc]~ing arm 9 will be urged by its own weight and the
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bias of the spring 16 downwardly in front of the end
of the outer telescopic tube 6 and, upon return of the
work surface 1 to the position illustrated in full lines,
locking engagement is achieved between the bevelled end
surfaces of the locking arm 9 and the tube 6.
In this position the load-absorbing stay 4 provides an
extremely stable support for the work surface 1 in the
absence of any risk of unintentional collapsing of the
work surface, since three mutually different hand manipu-
lations are required to collapse said surface. Thus, in
order to lower the work surface it must first be lifted
to the position shown in chain lines in Figure 1, in
order to free the locking arm 9 from the telescopic tube 6.
Pressure must then be applied to the sleeve-shaped part 10
in the direction of the arrow A, in order to swing the
locking arm 9 around the peg 11, against the action of the
spring 16, to bring the arm to the posi~tion shown in chain
lines in Figure 1. The work surface 1 must then be again
Z0 lowered to the position shown in full lines, while holding
the locking arm in the aforesaid position, whereafter the
locking arm can be released. When the locking arm is
released it slides over and along the telescopic tube 6
while lowering the work surface 1 to the position illustra-
ted in Figure 3.
If a particular application so requires, the work surfacema~ also be swung beyond the vertical position illustrated
in Figure 3, or may be stopped before said vertical posi-
tion is reached.
Because of its stable construction and the positive lock-
ing action afforded thereby, the stay can be fitted so
as to form onl~ a very small angle with the work surface 1
in the working position illustrated in Figure 1, this
feature being beneficial since a large part of the space
beneath the work surface is therewith made freely avail-
able.
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In addition to foldable work surfaces 1, a stay construc-
ted in accordance with the invention can be used with
other types of flaps or pivotable parts irrespective of
their orientation and pivotal directions. Because the
two ends of the stay can be mounted with the aid of
through-passing pegs, the stay can be fitted selectively
to any desired object. The stay can also be mounted
between two pivotable objects.
For certain applications it can be desireable to be able
to lock two relatively each other pivotable objects in
different relative positions, such as in case of writing
desks, drawing tables, ventilation flaps, etc. To this
end stay 4 can be modified as shown in Figures 4 and 5
in which like parts have the same reference numerals as
in ~igures 1 - 3.
The only difference between the modified stay and the
above described stay is that in the stay of Figures 4 and
5 the outer telescopic tube 6 is surrounded by two addi-
tional shorter tubes 18 and 19, respectively. The end
surface of each tube 6, 18 and 19 forms one engagement
shoulder for the locking arm. Hereby the stay of Figures
4 and 5 can be used to lock the work surface 1 in any of
three different positions relative to the other object 2,
as illustrated in Figure 5. To change the position of
the work surface between the different positions the same
manipulations have to be carried out as described above
in connection with Figures 1 - 3.
Instead of using three different tubes 6, 18 and 19 several
engagement shoulders can be provided on the outer surface
of the tube 6 in any suitable manner.
The aforedescribed embodiments of a stay according to the
invention are those at present preferred, although it will
be understood by those skilled in this art that various
1 0 ~,~'9~2~3
modifications can be made within the scope of the follow-
ing claims. This applies, for example, to the construc-
tion of the spring elements, the :Locking arm and the
mounting means. Although the tubes shown have a circular
cross section they can as well have a square or any other
cross section.
