VERTICALLY ADJUSTABLE DESKTOP, PREFERABLY A SCHOOL DESK

Abstract: The present invention relates to a vertically adjustable desk (1), preferably a school desk, with cooperating gas spring means (7), wherein a movable underbody (6) for the desk is supported by a stand (2) including a parallel linkage (3), at which one end of one piston rod of at least a gas spring means (7) is articulated connected at a distance along one of the movable links forming part of the linkage (3) from the articulating point at the underbody (6) and where the other end of the gas spring means (7) is articulated connected at the underbody (6), whereby the piston rod of the gas spring means (7) is locked unless a valve means is actuated. The invention is characterized in that the valve means of the gas spring means (7) is actuable by a handle means (8) adjacent to the desktop (1).

Description: Vertically adjustable desktop, preferably a school desk The present invention relates to a vertically adjustable desktop, preferably a school desk, which can be adjusted in a required vertical position by a simple manipulation and by a small adjusting force, at the same time to a great extend eliminating the risk for unintended or not permitted adjust¬ ment. As early as 1887 an adjustable desk was patented - see the SE-A-937. The problem solved regarded a possiblity to a vertically adjustment of a desktop and a bench dependent upon the size and the age of a child. This is also the case in SE- A-90.219 disclosing av desk being vertically adjustable by a complex gabel mechanism. Also SE-A-110.686 discloses a combination of a seat and a desk, and wherein a complicated handling is involved in adjusting the bench and the desktop. SE-A-20.872, SE-A-117.294 and SE-A-184.113 all disclose more or less complex mechanisms and devices to adjust the combination desk/seat. SE-B-8107530-1 discloses a balancing device at a table, preferably a drawing table, where the object is to eliminate the difficulties in adjusting the table to equilibrate the load on the table, which load can be about 15 - 60 kp. The working position forced onto youngsters during school work in an ordinary desk is often of that kind that it - by the unconscious ability of the body to try to compensate for distorted afflictions - forms the basis to continouing defective working positions in the later grown up working life. Thus it is of an extreme importance that young people as long as possible are able to change their working positions, i.e. already during the year at school, and preferably to make a simple variation of the working position or the physical position possible without necessarily stopping actual work, and if so is the case just for a few seconds. The object according to the present invention is to obtain a desk, preferably a desk for use at school, wherein a vertical adjustment can be performed infinitely with a simple manipulation and with a small adjusing force, whereby the risk for unintended or not permitted adjustement, e.g. when a person is sitting upon the desk, is eliminated. This object is achieved by a desk having the characterizing clauses stated in the claims. By making the underbody including a parallell linkage to which the one end of a gas spring means is articulately connected to form a lever to the articulated connection point in the underbody of the desk, the gas spring means will carry the weight of the desk (accumulating the potential energy of the desktop) during all vertical adjustment positions of the desk, wherein the rod piston of the gas spring means will remain locked unless a valve means in the gas spring means is actuated in connection to the adjustment, which takes place by adjusting handles in close connection to the desktop. Preferably two adjusting handles are arranged in connection to each of the gas spring means at the underbody of the desk and at the parallell linkage, i.e. two hands have to be used to adjust the vertical position of the desk. This is according to the present invention obtained without that the mechanism at the desk allowing this to happen in itself is voluminous or is intruding on the space for the legs under the desk. The invention will now be described in connection to one embodiment shown in the appended drawings, wherein Fig. 1 is a schematic side view - with some portions omitted to make the functions clear - of a desk i a lowered working position. Fig. 2 illustrates the desk according to fig. 1 in a middle position, and Fig. 3 illustrates a desk according to fig. 1 i the highest position, wherein the desktop is shown in a first folded position. In fig. 1 the desk is shown with a desktop 1, a lower stationary stand 2, a linkage 3 (of which just one half is shown in the figures), attachement points 4 and 5 at the stand 2 and at the underbody 6 of the desk, respectively. Prefer¬ ably the desk has a square desktop 1. Preferably the stationary stand 2 has a cross bar (not shown) a distance up on its vertical portion. There is also a cross bar between the two parts of the parallell linkage 3, preferably between the two upper links in the linkage . Preferably the underbody 6 also includes a cross bar (not shown) . At the underbody 6 - at each half (just one shown in the figure) - the one end of the gas spring means 7 is articulated connetcted. The movable pistons in this gas spring means are lockable or blockable through a valve and actuable by a handle 8 actuating the valve when a vertical adjustment of the desk top 1 shall take place. At this stage the gas spring means 7 allows a change in the vertical position of the desktop 1, whereby in the lower position shown in fig. 1 the gas spring is "charged" with the energy corresponding to the potential energy between the highest adjusting position (fig. 3) and the lowest adjusting position (fig. 1) . Thus, when actuating the handle 1 the energy is released from the gas spring means 7 performing a lifting force via the piston rod and the lever being formed at the upper link in the linkage 3 during a vertical adjustment upwards, and which essentially corresponds to the weights of the desktop 1 and of the underbody 6. In fig. 2 a middle adjusting position is shown wherein the piston rod of the gas spring means 7 can be seen in a more protruding position. In fig. 3 the highest adjusting position is shown where the piston rod of the gas spring means can be seen in its outmost protruding position. This figure illustrates that the gas spring means 7 in itself has been articulated around its point of connection in the desktop 1 supporting the underbody 6. In fig. 3 also the possibility to adjust the desktop 1 in a horisontal plane by a simple retaining mechanim is shown. To be able to handle the proportionately great forces acting upon and through the gas spring, the latter is preferably connetced in a closed U-grider. Yet another advantage with the present invention is obatined if the desktop is so arranged that it cannot be adjusted in a vertical direction when a certain excessive pressure exists i the gas spring means. This is done to eliminate the risk that the desktop unatentionally is adjusted downwards when a person is sitting on the desktop, or when the desk by some other reason is overloaded. The risk for this to happen is imminent when the desks are used at school. The invention is not restricted to the illustrated embodiment. Modifications can be made within the scoop of the appended claims.

Claims: CLAIMS 1. A vertically adjustable desk (1), preferably a school desk, with cooperating gas spring means (7), wherein a mobile underbody (6) for the desk is supported by a stand (2) including a parallell linkage (3) , at which one end of one pison rod of at least a gas spring means (7) is articulated connected at a distance along one of the moveable links forming part of the linkage (3) from the articulating point at the underbody (6) and where the other end of the gas spring means (7) is articulated connected at the underbody (6),. whereby the piston rod of the gas spring means (7) is locked unless a valve means is actuated, c h a r a c t e r i z e d i n that the valve means of the gas spring means (7) is actuable by a handle means (8) adjacent to the desktop (1) . 2. Desk according to claim 1, c h a r a c t e r i z e d i n that the gas spring means (7) is arranged to be not actutable when exceeding a predetermined pressure. 3. Desk according to claim 1 or 2, c h a r a c t e r i z e d i n that the gas spring means (7) is placed in a reinforced U- girder forming part of the underbody (6) .

Inventors: HOLMQUIST ROLAND, HOLMQUIST, ROLAND
Applicants: JELTEC ERGONOMITEKNIK AB
Application year: 1991
Main classification: A47B9
IPC codes: A47B9