DESK

Abstract: A desk capable of changing the height of a top board (3) through a height adjusting mechanism (5) within a specified range so as to simplify the desk by integrally realizing the top board height adjusting function and top board level adjusting function, wherein the top board (3) is supported by a plurality of telescoping leg columns (1), and the height adjusting mechanism (5) is formed so that the telescoping amount (L) of these leg columns (1) can be adjusted individually within a specified or a slightly larger adjusting range of the top board (3) by utilizing these leg columns (1).

Description: FIELD OF THE ART This invention relates to a height-adjustable desk according to the preamble of claim 1, cf. EP-A-0 743 033. BACKGROUND ART Desks are generally standardized at a height of a top plate to a certain degree. However, if several different standards exist or the standard varies in countries, a desk having a different specification has to be made according to the standard. In addition, a learning desk for children has to be changed in a height of a top plate in accordance with a growth degree of a child. However, it is a waste if the desk is traded for a new one every time the child grows. Under these circumstances, a desk wherein a height of a top plate can be changed by means of a height adjust mechanism has been developed and is in use presently. Generally, in an ordinary desk, adjusters are provided at a plurality of positions where each of a bottom end of the legs is supported and level adjustment by means of the adjusters makes it possible to cooperate with an uneven floor on which the desk is placed. In the above-mentioned desk, an adjuster adjust mechanism and a height adjust mechanism are separately incorporated into the desk. This increases a number of components and processing steps and it would become a factor which hinders a promotion of lowering cost and weight or of simplifying an arrangement of the desk. DISCLOSURE OF THE INVENTION In order to solve the above-mentioned problems, attention is paid to a point that both an adjuster adjust mechanism and a top plate height adjust mechanism are done by an operation of up and down. From the above viewpoint, these functions are carried out by a common mechanism in the desk of the invention. The desk in accordance with the invention is defined by claim 1. The leg support post may comprise a height adjust mechanism provided with a fixing member which fixes the grounding member to the support post member at a predetermined position. It is effective if the screw means comprises a nut member which is mounted on the support post member unrotatably and a screw shaft which projects upward over the grounding member and the projecting side is helically connected with the nut member. As described above, the desk in accordance with the invention has an arrangement in which the top plate is supported by a plurality of expansible leg support posts and the height adjust mechanism makes use of the leg support posts and can adjust an expansile amount of the leg support posts individually within the predetermined range through a little larger than the predetermined range. In accordance with the arrangement, when each of the leg support posts is adjusted to change substantially the same amount by operating the height adjust mechanism, the height of the top plate is also changed within the predetermined range in accordance with the adjusted amount. When several of the leg support posts are adjusted to change just a little, the level of the adjusted leg support posts only is changed, thereby to be able to cope with an uneven floor. As mentioned above, the height adjust mechanism carries out a function to adjust not only the height of the top plate but also the level of each leg support posts. Therefore, the cost and the weight of the desk can be reduced due to a common component used for different objects, and appearance of the desk can also be kept in a good looking condition. In addition, with the adjustment applied, it becomes possible to effectively adjust the top plate so as to be horizontal when placed on a steeply inclined floor. As a result, it becomes possible for the height adjust mechanism to carry out a function not only to adjust the height of the top plate but also to adjust a level of every leg support post individually and it can effectively conduct adjustment to an inclined floor. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is an overall perspective view showing one embodiment of the invention. Fig. 2 is a partially cut out perspective view of the embodiment. Fig. 3 is an exploded perspective view of a leg support post of the embodiment. Fig. 4 is an elevational cross sectional view of the leg support post. Fig. 5 is an explanatory view corresponding to Fig. 4. BEST MODES OF EMBODYING THE INVENTION The invention will be described in detail with reference to an embodiment thereof shown in the accompanying drawings. The desk has an arrangement, as shown in Figs. 1 through 4, in which each of four leg support posts 1 is connected at the upper end thereof through a frame 2 and a top plate 3 is supported by the frame 2. Each of the leg support posts 1 is of a square pipe and arranged at four corners or near the corners of the rectangular top plate 3 with an upper end of the leg support post 1 facing to an underside of the top plate 3. The frame 2 comprises a pair of right and left frame members 21 which connect the front and back leg support posts 1 along a direction of depth at adjacent the top end of the inner surfaces which face each other, a front frame member 22 which connects the right and left leg support posts 1 arranged front side along a direction of width at adjacent the top end of the inner surfaces which face each other, and reinforcing frame member 23 which connects the right and left frame members 21 at a little front of the center of the inner surfaces which face each other. This frame 2 constitutes a self standing structure together with each of the leg support posts 1 by prohibiting each other from being apart. Each of the right and left frame members 21 and the front frame member 22 is made of a common extruded form of a material having rigidity such as aluminum which is cut in a required length and is provided with a rail groove 21a, 22a which opens at one side facing inward of the frame members 21, 22. The reinforcing frame member 23 also is made of substantially the same extruded form of a material having rigidity such as aluminum which is cut in a required length and is provided with an opening as a rail groove 23a which opens at both sides of the reinforcing frame member 23. In this embodiment, brackets 4 each having a face 4a to support the top plate 3 are mounted on the right and left frame members 21 at two positions thereof, namely back and front of the right and left frame members 21 by making use of the above mentioned rail groove 21a and another bracket 4 having a face 4a to support the top plate 3 is mounted on the reinforcing frame member 23 at the center thereof by making use of the rail groove 23a. Then the top plate 3 is placed on the faces 4a of the above-mentioned five brackets 4 and fixed thereto by means of a screw from underside of the top plate 3. The top late 3 has an arrangement in which a plurality of materials for a top plate are overlapped along a direction of depth so as to show a grain of wood along a direction of width. With this arrangement, the top plate 3 produces a high strength against a load which is applied by placing something even if the top plate 3 is supported by the brackets 4 at only four corners and the center thereof. With the above arrangement, in this embodiment, the top plate 3 is so arranged that the height can be varied, for example, within a predetermined range of approximately 80 mm through the height adjust mechanism 5. In the height adjust mechanism 5, for making use of the leg support posts 1 as a construction element, the leg support posts 1 have an arrangement in which a support post member 11 and a grounding member 12 are expansibly connected to each other and an expansile amount of each leg support posts 1 can be adjusted individually within the above-mentioned predetermined range through a little larger than the range by means of a screw means 6. More specifically, the support post member 11 is made of a material having rigidity such as aluminum which is extruded into a square pipe. On the bottom end of the leg support posts 11 a nut member 61 having a threaded hole 61a at the center thereof is mounted with a part of the nut member 61 inserted thereinto so as to restrict the nut member 61 from being rotated. In the grounding member 12, a bottom end thereof forms a grounding area 12a and a side area 12b serves as a handling portion which has a shape of a nut with which a wrench is to be engaged from a side direction. And a screw shaft 62 projects upward from the upper face of the handling portion 12b. The screw means 6 comprises the threaded hole 61a and the screw shaft 62 and has an arrangement in which a projecting side of the screw shaft 62 is helically connected to the threaded hole 61a of the nut member 61. An effective range of the screw means 6 in which the screw shaft 62 is prevented from being out of joint of the threaded hole 61a is set at least a little larger than the above-mentioned 80 mm. Further, in this embodiment, a rectangle pipe cover 14 which is a little larger than the support post member 11 made of resin or something like that is arranged so that the upper end of the cover 14 fits over the support post member 11. On the inner face of the upper end of the cover 14 mounted is a close member 14a which closes a clearance between the support post member 11 and the cover 14. The cover 14 is arranged with an inner face 14b thereof affixed to an outer face 61b of the nut member 61. Then the cover 14 is affixed to two points, namely the outer face 11a of the support post member 11 and the outer face 61b of the nut member 61 through the close member 14a so as to make a sliding movement up and down without being loosened. The cover 14 is kept in a condition so as not to be apart from the support post member 11 because the close member 14a is kept in a tight contact with the cover 14 and the support post member 11 if no force is applied thereto. The cover 14 is so arranged that a lower end thereof covers the grounding member 12. A movable member 15 which alternatively exposes the handling portion 12b to a side of the cover 14 is mounted on the lower end of the cover 14 through a limit member 16. The movable member 15 is provided with an engaging claw 15a which faces outward at the upper end thereof and a hollow portion 15b which covers the grounding member 12 at the lower end thereof. The limit member 16 is provided with a clearance 16a which engages the engaging claw 15a with the lower end thereof so as to allow the engaging claw 15a to make an up and down movement and which restrains the up and down movement of the engaging claw 15 within a given range. The movable member 15 can be moved within the given range so as to alternatively expose or cover the side of the handling portion 12b. In the limit member 16, the upper face 16c serves as a role to set a limit on the lowest position of the nut member 61 and a through hole 16b through which the screw shaft 62 is to be passed is provided at the center of the limit member 16. Next a method to deal with this embodiment will be explained. First, lift up the movable member 15 as shown in Fig. 5 from a condition shown in Fig. 4 so as to expose a side of the handling portion 12b. Next, engage a wrench which is not shown in drawings with the handling portion 12b and rotate the screw shaft 62 to a predetermined direction so as to move the nut member 61 along an axial direction of the screw shaft 62. Then an amount of the grounding member 12 projecting from the support post member 11, namely, an expansile amount L of the leg support post 1 as a whole can be adjusted within a range as far as the nut member 61 engages with the screw shaft 62. With the same manner applied to all of the other leg support posts 1, the height of the top plate 3 can be changed within a range, for example, 680 mm to 760 mm. It is a matter of course the above operation can be done with the desk placed upside down and lower end of the leg support posts 1 protruded upwardly. In case the top plate 3 is not stably placed horizontally due to an error of adjustment or unevenness of the floor F even if the desk is placed on a floor F with the grounding area 12a of the leg support post 1 being grounded after the height of the top plate 3 is adjusted, adjust only the required leg support post 1 in the same manner as in the case of the above so as to move the grounding member 12 a very slight amount with a wrench applied to the handling portion 12b of the required leg support post 1. Then the height of each leg support posts 1 can be adjusted individually. As mentioned above, in this embodiment, the height adjust mechanism 5 which makes use of expansion and contraction of the leg support post 1 carries out a function to adjust not only the height of the top plate 3 but also the level of each leg support posts 1. Therefore, the number of components and the number of working steps required for manufacture and assembly is greatly reduced as compared with conventional desks in which these functions are carried out by different mechanisms, thereby to reduce the cost and the weight of the desk as a whole and to simplify the arrangement of the desk. In addition, with applying the adjustment, if, for example, one pair of the two pairs of the leg support posts 1 which support two sides of the top plate 3 facing each other are adjusted to have the same expansible amount and the other pair are adjusted differently, the top plate 3 can be adjusted so as to be horizontal when placed on a steeply inclined floor F . Further, since these functions accompany to the leg support post 1 alone, in other words, do not accompany to the top plate 3 or the like, an arrangement of the top plate 3 can be simplified and this makes it possible to prevent the space under the desk from being unreasonably reduced and to improve the appearance of the leg support post 1. Especially, in this embodiment, since the leg support post 1 comprises the support post member 11 and the grounding member 12 which is arranged at the lower end of the support post member 11 and which can protrude or recede, and the height adjust mechanism 5 comprises the screw means 6 which helically connects the support post member 11 to the grounding member 12 with allowing the support post member 12 to make an up and down movement, a stable and smooth movement can be obtained with an extremely easy operation and the grounding member 12 can be securely kept at a desired position by making use of the self-lock mechanism of the screw means 6 without any other fixing members. Since the screw means 6 basically comprises the nut member 61 which is mounted on the support post member 11 unrotatably and the screw shaft 2 which projects upward over the grounding member 12 and the projecting side is helically connected with the nut member 61, required function can effectively be obtained with the least required number of components. In this case, since the handling portion 12b for rotating the screw shaft 62 is formed in the side of the grounding member 12, a common component can be shared, and since the handling portion 12b can be operated just near the grounding member 12, it becomes easy to operate the handling portion 12b. Further, in this embodiment, the cover 14 is attached to the support post member 11 with an upper end thereof allowed to make a sliding movement up and down, and the lower end of the cover 14 always covers the grounding member 12, even if the leg support post 11 is expanded, for example, as shown in Figs, 4 and 5, resulting in keeping an appearance of the leg support post 1 in a good looking condition. In this case, since the movable member 15 which alternatively exposes the handling portion 14b to the outside of the cover 14 is provided at the lower end of the cover 14, there is no need of moving the cover 14 so as to slide every time the handling portion 14b is handled, thereby to simplify the operation of adjusting a level of the leg support post 1. The component parts are not limited to the illustrated constructions, but there may be various modifications and changes without departing from the scope of the invention. For example, this does not exclude an arrangement in which a fixing member such as a screw fixes the support post to the grounding member which constitutes the leg support post at a predetermined position. The above-mentioned position is just one embodiment of the invention, and it is needless to say that the adjustable amount of the top plate or the level can be set at any amount tailored to an object or a usage of the desk. Further, the desk described in this specification also includes a concept of, so to speak, a table. POSSIBLE APPLICATIONS IN INDUSTRY As mentioned above, the desk in accordance with the invention is used when it is needed that a height of the top plate be changed according to a user's requirement, especially preferably used for a learning desk for children which is required to change a height of the top plate according to a growing rate of the child. The desk is also preferably used in a case a floor on which the desk is to be placed is steeply inclined.

Claims: A desk in which a height of a top plate (3) can be varied within a predetermined range through a height adjust mechanism (5), said top plate (3) is supported by a plurality of expansible leg support posts (1), and said height adjust mechanism (5) makes use of said leg support posts (1) and can adjust an expansible amount of said leg support posts individually within said predetermined range through a little larger than said predetermined range; characterized in that said leg support post (1) comprises a support post member (11) and a grounding member (12) which is arranged at the lower end of the support post member (11) with allowing a movement to protrude or recede, and said grounding member (12) further comprises a handling portion (12b); the height adjust mechanism (5) comprises a screw means (6) which helically connects said support post member (11) and said grounding member (12), said screw means providing an up and down movement through an operation of said handling portion (12b); a cover (14) is mounted on said support post member (11) with the upper end thereof allowed to make sliding movement up and down and said cover (14) is so arranged that a lower end thereof covers said grounding member (12) and said handling portion (12b), and a movable member (15) which alternatively exposes said handling portion (12b) is provided at a part of an underside of the cover (14). The desk, described in claim 1 and characterized by that said height adjust mechanism (5) is provided with a fixing member which fixes said grounding member (12) to the support post member (11) at a predetermined position. The desk, described in claim 1 or 2 and characterized by that said screw means (6) comprises a nut member (61) which is mounted on the support post member (11) unrotatably and a screw shaft (62) which projects upward over the grounding member (12) and the projecting side is helically connected with said nut member (61).

Inventors: FRENKLER FRITZ, KOLBERG JUSTUS, FRENKLER, FRITZ, KOLBERG, JUSTUS
Applicants: KOKUYO KK, KOKUYO CO., LTD.
Application year: 1999
Main classification: A47B9
IPC codes: A47B9, A47B91