WO2007119975A1

WO2007119975A1 - Height adjustable furniture

Info

Publication number: WO2007119975A1
Application number: PCT/KR2007/001803
Authority: WO
Inventors: Sun Koo Hong
Original assignee: Sun Koo Hong
Priority date: 2006-04-14
Filing date: 2007-04-13
Publication date: 2007-10-25
Also published as: KR200423262Y1

Abstract

A height adjustable furniture such as a desk, chair, and table is provided. The height adjustable furniture transfers an elevation rotational force which is produced in a forward or backward direction through an elevation drive portion to a pair of worm gears which are spaced from each other and are engaged with a rack gear which is formed in the inner frame of the furniture. Accordingly, the height of the furniture can be conveniently- adjusted to match the physical structure of a user.

Description

HEIGHT ADJUSTABLE FURNITURE

Technical Field The present invention relates to a height adjustable furniture such as a desk, chair, and table, or more particularly, to- a height adjustable furniture such as a desk, chair, or table which transfers an elevation rotational force which is produced in a forward or backward direction through an elevation drive portion to a pair of worm gears which are spaced from each other and are engaged with a rack gear which is formed in the inner frame of the furniture, to thereby conveniently adjust the height of the furniture to match the physical structure of a user.

Background Art

Height adjustable furnitures such as desks, chairs, and tables (hereinafter, referred to as desks) have been developed in various forms, because they are of advantages capable of adjusting their heights to be fit with figures of users unlike conventional desks.

The height adjustable desks are formed of the most typical structure capable of adjusting heights thereof by connecting and disconnecting a fixing pins or fixing screws into and from penetrating holes of a fixing rod, respectively. Thus, the height adjustable desks need tools such as drivers and a lot of difficulties occur in use due to frequent troubles of a height adjuster.

Korean Utility-model Registration No. 20-0411817 discloses a desk height adjuster to solve shortcomings of the conventional method of using fixing pins or fixing screws. However, the height adjusters should be separately installed in the respective legs of desks using the height adjusters. Thus, in order to adjust height of a desk, workers of at least two persons should adjust the height of the desk jointly and cooperatively.

Also, Korean Utility-model Registration No. 20-0409712 discloses a desk equipped with desk height adjusters using helical gears. However, since this kind of the desk structure has very complex gear engagement, it is disadvantageous in view of a production cost. It also becomes an important factor of preventing maintenance or repair of the adjuster of the height adjustable desk from being easily performed. Further, the conventional height adjustable desk has a shortcoming of consuming a considerable force in order to circumvolve rotational knobs which protrude outwards.

Disclosure of the Invention

To overcome the conventional shortcomings, it is an object of the present invention to provide a height adjustable furniture such as a desk, chair, and table having a simple and strong structure to thus perform easy maintenance as well as freely adjust height of furniture even with a small force. To accomplish the above object of the present invention, there is provided a height adjustable furniture such as a desk, chair, and table comprising: a pair of support frames respectively formed of an outer frame combined with a bottom member and an inner frame combined with an upper plate member, in which the inner frame which is fitted into the inside of the upper portion of the outer frame is selectively elevated up and down, wherein an elevation drive portion is installed in either end of the pair of the support frames, wherein the elevation drive portion is combined mutually symmetrically with the left and right sides of the outer frame and comprises: a pair of worm gear housings having a worm gear therein, respectively; a power connection member which connects the worm gears in the worm gear housings in a mutually spaced structure; and a ratchet gear which is installed in one side of the power connection member, to thus provide a rotational force of a forward or backward direction, wherein rack gears are formed in one side of the inner frame, and wherein the worm gears are combined along the axial line of the power connection member and are engaged with the respective rack gears to thereby transfer power which is generated from the elevation drive portion to the rack gears by the worm gears so that the height of the height adjustable furniture can be adjusted while the inner frames ascend or descend. Preferably but not necessarily, each worm gear and each rack gear are formed of a symmetrical gear line.

Preferably but not necessarily, each of the worm gears comprises a worm and a worm wheel, in which a gear ratio between the worm and the worm wheel is 30:1 through 38:1.

Preferably but not necessarily, the height adjustable furniture further comprises a first bushing member having a first stopper which is seated in the outer frame and a first hollow accommodation portion which is accommodated in the upper space of the outer frame, in which the first stopper comprises an outer frame seating groove to which the upper end of the outer frame is fixed, and the first hollow accommodation portion comprises a worm gear catch prevention recess for preventing the worm gears from catching. Preferably but not necessarily, the first bushing member further comprises a rack gear catch prevention recess which is formed with a predetermined depth along the inner circumferential surface toward the side where the worm gear catch prevention recess is formed, t thereby prevent the rack gears from catching, and an insertion auxiliary recess which is formed with a predetermined depth along the outer circumferential surface toward the side where the worm gear catch prevention recess is formed, to facilitate insertion of the rack gears.

Preferably but not necessarily, the height adjustable furniture further comprises a second bushing member having a second stopper which is seated in the inner frame and a second hollow accommodation portion which is accommodated in the inner frame, in which a friction prevention groove for reduction of friction during moving in the inner frame is formed on the outer circumferential surface of the second stopper.

Preferably but not necessarily, the second stopper has an outer diameter which is same as that of the first accommodation portion.

Preferably but not necessarily, the height adjustable furniture further comprises a level adjuster for adjusting a level of the bottom member, wherein the level adjuster comprises: an upper adjuster having a body portion which is screw-coupled with the bottom member, a handle portion which is formed in the upper end of the body portion, and a semi-circular protrusion which is formed in the lower end of the body portion; and a lower base having a mortar-shaped body portion and a semi-circular groove in which the semi-circular protrusion of the upper adjuster is inserted and fixed.

Preferably but not necessarily, the height adjustable furniture further comprises a sealer for measuring height and a height indicator having a measuring weight.

Brief Description of the Drawings.

FIG. 1 is a perspective view showing a height adjustable desk according to an exemplary embodiment of the present invention; FIG. 2 shows views for explaining an assembly process of an elevation drive portion of FIG. 1;

FIG. 3 shows views for explaining a symmetry of a rack gear formed in one side of an inner frame of FIG. 1; FIG. 4 shows views showing a first bushing member of FIG. 1;

FIG. 5 shows views showing a second bushing member of FIG. 1;

FIG. 6 shows cross-sectional views for explaining an assembly process of a level adjuster of FIG. 1; and FIGS. 7 and 8 show use states of height adjustable desk according to the exemplary embodiment of the present invention.

Best Mode for Carrying out the Invention Hereinbelow, a height adjustable furniture such as a desk, chair, and table (hereinafter referred to as a desk) according to an exemplary embodiment of the present invention will be described with reference to the accompanying drawings. Like reference numerals are assigned for like member in the drawings. Referring to FIG. 1, a height adjustable desk according to an exemplary embodiment includes a bottom member 10 such as a support bar or support plate which is put on a floor, a plate-shaped member 20 such as the upper plate of a desk or a seat plate of a chair, a pair of support frames 30 and 40 which connect the bottom member 10 and the plate-shaped member 20 with each other, and an elevation drive portion 50.

The pair of support frames 30 and 40 include outer frames 31 and 41 whose lower ends are fixedly coupled with both sides of the bottom member 10, and inner frames 33 and 43 which are fixedly coupled with the lower ends of both sides of the plate-shaped member 20, respectively. The lower ends of the inner frames 33 and 43 are inserted into the hollow inner portions of the outer frames 31 and 41 through the upper ends of the outer frames 31 and 41. In this state, the inner frames 33 and 43 are selectively ascend or descend up and down by the elevation drive portion 50. Accordingly, height of the desk or chair can be adjusted. Here, the cross-sectional shapes of the pair of support frames 30 and 40 may be ordinarily circular or rectangular. Besides, the cross-sectional shapes of the pair of support frames 30 and 40 may be triangular or other shapes .

The elevation drive portion 50 is transversely installed on both ends of the pair of support frames 30 and 40. The elevation drive portion 50 includes a pair of worm gear housings 51 and 53 having a worm gear therein, respectively; a power connection member 55 which connects the worm gears in the worm gear housings in a mutually spaced structure; and a ratchet gear 57 which is installed in one side of the power connection member, to thus provide a rotational force of a forward or backward direction.

The pair of worm gear housings 51 and 53 are mutually symmetrically combined with both left and right side surfaces of the outer frames 31 and 41, and have a worm gear which converts a rotational motion into a rectilinear motion in their inside thereof.

A worm gear according to an exemplary embodiment of the present invention is a kind of an electric power transmission apparatus. As will be explained later in detail, a screw-shaped gear formed of several spiral lines is called a worm, in which the shape of the worm is cylindrical. A gear which is engaged with the worm is called a worm wheel. A pair of a worm and a worm wheel is called a worm gear. The worm wheel is similar to a helical gear and has a pointed gear line slantingly to thus rotate along the spiral lines of the worm. The axes of the worm and the worm wheel form a right angle, and the worm and the worm wheel are preferably designed so that the rotational force is not transferred from the worm wheel to the worm.

Referring to FIG. 2, first and second space portions 51Al and 53Al; 51Bl and 53Bl having built-in worm gears formed of worm wheel 51A and 53A and worm gears 51N and 53B are provided in the inside of the worm gear housings 51 and 53. The first space portions 51Al and 53Al and the second space portions 51Bl and 53Bl are formed perpendicularly with each other.

The worm wheels 51A and 53A fixed by fixed axes 51A2 and 53A2 and engaged with the worms 51B and 53B, are rotatably inserted in the first space portions 51Al and 53Al, respectively. Here, the worm wheels 51A and 53A are engaged with the rack gear 33A which is formed on either one side of the inner frames 33 and 43 via a throughhole 3IA which is vertically lengthily formed is on the sides of the outer frames 31 and 41, respectively (see FIG. 7) .

The second space portions 51Bl and 53Bl are penetratively formed in the axial direction of the power connection member 55, and the worms 51B and 53B combined with the power connection member 55 are rotatably inserted into the second space portions 51B1 and 53Bl, respectively. Here, assistance axes 51C and 53C for reinforcing a rotational force of the worms are provided at the end of the worms 51B and 53B, and are fitted into a groove formed in each outer frame, for example, a groove 31B.

In particular, the worm gear of this invention is designed so that a gear line is mutually symmetrically arranged to provide an identical direction of rotation. For example, a gear ratio between the worm and the worm wheel is 30:1 through 38:1, and preferably 36:1.

As illustrated in FIG. 3, the rack gears 33A and 43A are formed in one side of the inner frames 33 and 43, but the gear line of the rack gears 33A and 43A are mutually symmetrically formed. Therefore, the worm gears provided in one pair of the worm gear housings are combined on the axial line of the power connection member 55, respectively and are engaged with the rack gears 33A and 43A, respectively. Accordingly, power which is generated from the elevation drive portion 50 is transferred to the rack gears by the worm gears. As a result, the height of the height adjustable desk can be adjusted while the inner frames 33 and 43 ascend or descend.

A ratchet gear 57 is installed in one side of the power connection member 55. Concretely, the power connection member 55 is inserted and fixed into the central hole of a head portion 57A of the ratchet gear 57 and receives a rotational force of a forward or backward direction directly from the ratchet gear 57. Here, power conversion of the forward or backward direction is achieved by manipulating a power converter 57C. Since composition of the ratchet gear has already been known, the detailed description thereof will be omitted.

Meanwhile, the inner frames which are respectively fitted into the inside of the upper portions of the outer frames are made to operate to ascend or descend to adjust the height of a desk or chair. In this case, one to consider is to make the inner frame smoothly slide in the outer frame, and prevent the inner frame from shaking. For this purpose, the height adjustable desk according to this invention includes a first bushing member 60 which is provided in each of the outer frame 31 and 42, and a second bushing member 70 which is provided in each of the inner frames 33 and 43.

Referring to separate views (a) through (e) of FIG. 4, the first bushing member 60 includes a first stopper 61 which is seated in the outer frame and a first hollow accommodation portion 63 which is accommodated in the upper space of the outer frame. The first stopper 61 includes an outer frame seating groove 61A to which the upper end of each of the outer frames 31 and 41 is inserted and fixedly seated.

The first hollow accommodation portion 63 includes an insertion auxiliary groove 63A of a given depth in the outer circumferential surface thereof in order to enable a smooth insertion even in the case there is a welding portion in the outer frame. The insertion auxiliary groove 63A can be formed extensively up to a part of the first stopper 61.

In addition, the first hollow accommodation portion 63 includes a rack gear catch prevention groove 63B and a worm gear catch prevention recess 63C.

The rack gear catch prevention groove 63B is formed to a given depth in the lengthy direction of the first hollow accommodation portion 63 from the first stopper 61 along the inner circumferential surface of the side where the worm gear catch prevention recess 63C is formed, and thus plays a role of preventing the rack gears 33A and 43A from being caught during moving of the inner frames 33 and 43. Here, the width of the rack gear catch prevention groove 63B is same as or greater than that of the rack gear. The worm gear catch prevention groove 63C is provided to consider a problem that the worm wheels 5IA and 53A of the worm gear are caught by the lower end of the first bushing member 60 and thus do not operate, when the worm gear housings 51 and 53 are combined with the outer frames 31 and 41, respectively, and.then the first bushing member 60 is combined with the upper end of the outer frames 31 and 41.

Referring to separate views (a) through (c) of FIG. 5, the second bushing member 70 includes a second stopper 71 which is seated in each of the inner frames 33 and 43 and a second hollow accommodation portion 73 which is accommodated in the inner frame. A friction prevention groove 71A for reduction of friction due to a welding portion in the outer frame during moving of the inner frame is formed on the outer circumferential surface of the second stopper 71. The second hollow accommodation portion 73 has a groove 73A of a cross form which makes it easy to accommodate the second hollow accommodation portion 73 into the inner frame.

Preferably, the second stopper 71 has an outer diameter which is same as that of the first accommodation portion 61 of the first bushing member 60 (L1=L2) . As shown as separate views (a) and (b) in FIG. 6, four level adjusters 80 for adjusting the level of the bottom member are provided on the bottom member 10.

Each of the level adjuster 80 includes an upper adjuster 81 and a lower base 83. The upper adjuster 81 includes a body portion 81B which is screw-coupled with the bottom member 10, a handle portion 8IA which is formed in the upper end of the body portion 81B, and a semi-circular protrusion 81C which is formed in the lower end of the body portion. The lower base has a mortar-shaped body portion 83A and a semi-circular groove 83B in which the semi-circular protrusion 81C of the upper adjuster is inserted and fixed.

A spring 85 mounts in the body portion 81B. The spring 85 is formed of a pyramid form as an exclusive coil spring (which is called a snail spring) , and when the spring 85 has been pressed down, it is elastic and attached closely on a floor in a narrow space, to thereby prevent unnecessary motions of the handle.

A helix 11 is formed in the bottom member 10 so that the upper adjuster 81 can be screw-combined with the bottom member 10. A space portion 13 in which the lower base 83 can be inserted is formed in the bottom member 10.

When the upper adjuster 81 and the lower base 83 are combined with each other, the semi-circular protrusion 81C of the upper adjuster 81 is combined into the semi-circular groove 83B of the lower base 83. Accordingly, the level is not only maintained but also a buffering effect is provided. Particularly, unlike the existing methods, the upper adjuster 81 is combined from the

■ up-direction to the down-direction to thereby achieve a level adjustment. As a result, the height adjustable desk according to the present invention has an advantage capable of using it very conveniently.

In addition, the height adjustable desk further includes a height indicator 90 including a sealer 91 and a measuring weight

93, to thereby enable a user to measure height of the height adjustable desk. For example, sealer 91 can be attached in the form of a sticker on the outer side of one 31 of the outer frames. The measuring weight 93 is fixedly combined with the upper plate member 20 or the inner frame 33.

Hereinbelow, the height adjustment actions of the height adjustable desk according to the present invention will be sequentially described (see FIGS. 7 and 8).

First, to ascend or descend the plate-shaped member 20 to a predetermined height, a user manipulates the power converter 57C of the ratchet gear 57. Accordingly, power conversion of a forward or backward direction is determined and the handle portion 57B is repeatedly made to operate.

The power connection member 55 receives a rotational force of a forward or backward direction directly from the ratchet gear 55 by manipulation of the ratchet gear 57, to then rotate in a forward or backward direction. Accordingly, the worm gears in the worm gear housings 51 and 53 which are combined on the axial line of the power connection member 55 rotates in a one-direction.

The worm gear has a structure that the worm wheel 51A is tooth-engaged with the worm 51B to then rotate, in which the worm wheel 51A is engaged with the rack gear 33A which is formed on the one side surface of the inner frame 33. Accordingly, the worm wheel 51A is tooth-engaged with the rack gear 33A to then rotate so that the inner frame 33 ascends toward the upper portion or descends toward the lower portion. As a result, height of the plate-shaped member 20 combined with the inner frame ascends or descends together. If the level of a desk or chair is not uniform, the four level adjusters 80 provided in the bottom member 10 are properly- controlled to adjust the level of the desk or chair.

In addition, in the case that the plate-shaped member 20 ascends or descends, a user measures the height of the desk or chair with the eye, through the height indicator 90 to thus set the height of the desk or chair at his or her desired height.

As described above, the present invention has been described with respect to particularly preferred embodiments. However, the present invention is not limited to the above embodiments, and it is possible for one who has an ordinary skill in the art to make various modifications and variations, without departing off the spirit of the present invention. Thus, the protective scope of the present invention is not defined within the detailed description thereof but is defined by the claims to be described later and the technical spirit of the present invention.

As described above, the present invention provides a height adjustable desk which transfers an elevation rotational force which is produced in a forward or backward direction through an elevation drive portion to a pair of worm gears which are spaced from each other and are engaged with a rack gear which is formed in the inner frame of the desk, to thereby conveniently adjust the height of the desk or chair to easily match the physical structure of even a user such as children, the old, and the disabled. Further, the height adjustable desk or chair according to the present invention having a structure of adjusting the height by a gear ratio, is semi-permanent . Even in the case that an excessive force is applied to the upper plate member, the fixed state of the height adjustable desk or chair can be stably maintained.

Industrial Applicability

As described above, the present invention provides a height adjustable desk or chair having a simple and strong structure to thus perform easy maintenance as well as freely adjust height of desk even with a small force.

Claims

What is claimed is:

1. A height adjustable furniture such as a desk, chair, and table comprising: a pair of support frames respectively formed of an outer frame combined with a bottom member and an inner frame combined with an upper plate member, in which the inner frame which is fitted into the inside of the upper portion of the outer frame is selectively elevated up and down, wherein an elevation drive portion is installed in either end of the pair of the support frames, wherein the elevation drive portion is combined mutually symmetrically with the left and right sides of the outer frame and comprises: a pair of worm gear housings having a worm gear therein, respectively; a power connection member which connects the worm gears in the worm gear housings in a mutually spaced structure; and a ratchet gear which is installed in one side of the power connection member, to thus provide a rotational force of a forward or backward direction, wherein rack gears are formed in one side of the inner frame, and wherein the worm gears are combined along the axial line of the power connection member and are engaged with the respective rack gears to thereby transfer power which is generated from the elevation drive portion to the rack gears by the worm gears so that the height of the height adjustable furniture can be adjusted while the inner frames ascend or descend.

2. The height adjustable furniture according to claim 1, wherein each worm gear and each rack gear are formed of a symmetrical gear line.

3. The height adjustable furniture according to claim 2, wherein each of the worm gears comprises a worm and a worm wheel, in which a gear ratio between the worm and the worm wheel is 30:1 through 38:1.

4. The height adjustable furniture according to claim 1, further comprising a first bushing member having a first stopper which is seated in the outer frame and a first hollow accommodation portion which is accommodated in the upper space of the outer frame, in which the first stopper comprises an outer frame seating groove to which the upper end of the outer frame is fixed, and the first hollow accommodation portion comprises a worm gear catch prevention recess for preventing the worm gears from catching.

5. The height adjustable furniture according to claim 4, wherein the first bushing member further comprises a rack gear catch prevention recess which is formed with a predetermined depth along the inner circumferential surface toward the side where the worm gear catch prevention recess is formed, t thereby prevent the rack gears from catching, and an insertion auxiliary recess which is formed with a predetermined depth along the outer circumferential surface toward the side where the worm gear catch prevention recess is formed, to facilitate insertion of the rack gears.

6. The height adjustable furniture according to claim 4, further comprising a second bushing member having a second stopper which is seated in the inner frame and a second hollow accommodation portion which is accommodated in the inner frame, in which a friction prevention groove for reduction of friction during moving in the inner frame is formed on the outer circumferential surface of the second stopper.

7. The height adjustable furniture according to claim 6, wherein the second stopper has an outer diameter which is same as that of the first accommodation portion.

8. The height adjustable furniture according to claim 1, further comprising a level adjuster for adjusting a level of the bottom member, wherein the level adjuster comprises: an upper adjuster having a body portion which is screw-coupled with the bottom member, a handle portion which is formed in the upper end of the body portion, and a semi-circular protrusion which is formed in the lower end of the body portion; and a lower base having a mortar-shaped body portion and a semi-circular groove in which the semi-circular protrusion of the upper adjuster is inserted and fixed.

9. The height adjustable furniture according to claim 1, further comprising a sealer for measuring height and a height indicator having a measuring weight.