EP2499934A1

EP2499934A1 - Piece of furniture with top plate

Info

Publication number: EP2499934A1
Application number: EP10830017A
Authority: EP
Inventors: Hidetaka Sekikawa
Original assignee: Okamura Corp
Current assignee: Okamura Corp
Priority date: 2009-11-12
Filing date: 2010-11-12
Publication date: 2012-09-19
Also published as: WO2011059058A1; KR20120096485A; CN102711556A; US20120227642A1; EP2499934A4; CA2780684A1

Abstract

In order to provide a piece of furniture with a top plate, configured in such a manner that gas springs are provided to both left and right leg bodies to enable the top plate to be easily raised and lowered even if the top plate is heavy and that the top plate is prevented from tilting when being raised and lowered, the piece of furniture with a top plate is provided with the top plate 2 and a pair of left and right leg bodies for supporting left and right side sections of the top plate 2 and is configured so that the height position of the top plate 2 can be changed by raising and lowering the top plate. The leg bodies are each provided with: a fixed leg column installed on the floor surface; a movable leg column supported by the fixed leg column and capable of being lifted and lowered, a gas spring extended and retracted in the vertical direction to assist the lifting and lowering of and fixation of the height position of the movable leg column; a switching means 19 for switching a state of the gas spring between an extendable state and a fixed state. The top plate 2 is provided with an operation means 9 for operating the switching means 19 to be operated simultaneously when the operation means 9 is operated.

Description

TECHNICAL FIELD

The present invention relates to a piece of furniture with a top plate and a height of which can be changed by raising or lowering the top plate.

BACKGROUND ART

An over-bed table (a piece of furniture with a top plate) according to the related art has a gas spring in one of a pair of left and right extendable and retractable legs (leg bodies), so that when the top plate is raised, a push rod of the gas spring is pushed by an operating lever (operation means) provided at a top side of the extendable and retractable leg to assist raising and/or lowering of the top plate by a pressing force of the gas spring. An operating lever is provided at a top side of an extendable and retractable leg without the gas spring, so that even when an operator is situated at either the left or right side of the over-bed table, raising and lowering of the top plate can be operated (for example, see Patent Document 1).
For example, as disclosed in Patent Document 2, in a piece of furniture with a top plate according to the related art, leg bodies are configured by a pair of left and right guide rods (outer leg columns), and elevation rods (inner leg columns) which can smoothly move vertically along the guide rods. Further, a gas spring is provided in one leg body to assist raising and/or lowering of the top plate and fix a height of the top plate, and an adjusting means (elevation synchronizing means) is configured by a plurality of pulleys (synchronizing pulley members) and a wire (synchronizing wire member) hung on the pulleys, so that it makes difficult to generate an elevation error in the left and right elevation rods, and the left and right sides of the top plate can be synchronously raised with good balance. Further, various synchronizing means and extension synchronizing means (elevation synchronizing means) of the same type are disclosed in Patent Documents 1 and 3.

PRIOR ART REFERENCE

PATENT DOCUMENT

[Patent Document 1]: Japanese Patent No. 2761706 (page 3, page 4, FIG. 2, and FIG. 5)
[Patent Document 2]: Japanese Patent Application Laid-Open Publication No. 1998-179266 A (page 3 and FIG. 7)
[Patent Document 3]: Japanese Patent No. 3681001 (page 4 and FIG. 3)

SUMMARY OF THE INVENTION

PROBLEM TO BE SOLVED BY THE INVENTION

In the over-bed table (a piece of furniture with a top plate) described in Patent Document 1, since a gas spring is provided only in one extendable and retractable leg (leg body), such a configuration cannot be applied to a table with a large-sized heavy top plate, requiring the gas spring to be provided in both left and right extendable and retractable legs. However, when the gas springs are provided in both the left and right extendable and retractable legs, if the pressing timings of push rods for the gas springs become different, one of the gas springs is extended or retracted first, causing the top plate to be tilted.
In the height adjusting means (elevation synchronizing means) of a top plate of a desk described in Patent Document 2, it is required to fix an end of a wire (synchronizing wire member) of the adjusting means or a pulley (synchronizing pulley member) to a guide rod (outer leg column). Further, the wire or pulley is accommodated within a cover member provided at a side of a leg body to be prevented from being interfered with a gas spring. Accordingly, a width of the leg body or the like including the cover member increases and a weight thereof also increases. Patent Documents 1 and 3 also have a similar problem.
The present invention has been made in an effort to provide a piece of furniture with a top plate, which is configured such that gas springs are provided in both left and right leg bodies to enable the top plate to be easily raised even if the top plate is heavy and the top plate can be prevented from being tilted when the top plate is being raised or lowered.
Further, the present invention has been made in an effort to provide a piece of furniture with a top plate, which is configured such that elevation synchronizing means for synchronously raising and/or lowering left and right side sections of the top plate and gas springs are accommodated in the leg bodies compactly to be able to reduce weights of leg bodies.

MEANS FOR SOLVING THE PROBLEM

In order to solve the problem, a piece of furniture with a top plate of the present invention includes a top plate and a pair of left and right leg bodies which supports left and right sides of the top plate, wherein a height position is changeable by raising or lowering the top plate, the piece of furniture is characterized in that each of the leg bodies includes a fixed leg column installed on a floor surface, a movable leg column supported by the fixed leg column to be raised and lowered, a gas spring which is extendable and retractable vertically to assist raising and lowering of the movable leg column and fixation of a height position of the movable leg column, and a switching means which switches an extendable state and a fixed state of the gas spring, and an operation means which operates the switching means is provided in the top plate, and a switching synchronizing means is provided to simultaneously operate each of the switching means when the operation means is operated.
According to this feature, a vertical location of the top plate can be adjusted by an operation of the gas spring. Even a heavy top plate can be easily raised and lowered by two gas springs of both the left and right leg bodies. Since extendable states and fixed states of the left and right gas springs can be simultaneously switched by the switching synchronizing means for operating the switching means at the same time, the top plate is prevented from being tilted due to asynchronous switching of the gas springs.
The piece of furniture of the present invention is characterized in that the switching means serves as an operating member which operates an operating part of the gas spring and is provided with a flexible operating wire member which connects each of the operating member, and the switching synchronizing means is configured by providing a movable member which moves a substantially central portion of the operating wire member in a direction other than a direction in which the flexible operating wire member extends.
According to this feature, when the flexible operating wire member is moved in a direction other than a direction in which the operating wire member extends by the movable member when the operation means is operated, left and right ends of the operating wire member connected to the operating members is moved equally in a direction in which the operating wire member extends, so that the operating parts of the gas springs can be operated simultaneously. Accordingly, the switching synchronizing means can be constituted with a simple structure including the operating member, the operating wire member, and the movable member.
The piece of furniture of the present invention is characterized in that the movable member is adapted to pull the substantially central portion of the operating wire member, and the substantially central portion of the operating wire member smoothly moves on a contact surface of the movable member.
According to this feature, if the operation means is operated, both left and right ends of the operating wire member is moved toward a substantially central portion so that both the left and right ends of the operating wire member can be moved equally. Further, even when there is an error between lengths of the operating wire member from the movable member to the operating members, the error can be offset by smoothly moving the operating wire member on the contacting surface with the movable member.
The piece of furniture of the present invention is characterized in that the substantially central portion of the operating wire member is coupled to an operating pulley member of the movable member, and a vicinity of a portion of the operating wire member coupled to the operating pulley member is maintained to smoothly move on a maintaining part fixed to the top plate.
According to this feature, even when an error occurs between the lengths of the operating wire member from the movable member to the operating members, the operating wire member is moved in a direction in which the operating wire member extends through rotation of the operating pulley member, so that the error can be offset. A vicinity of a portion of the operating wire member coupled to the operating pulley member is maintained by the maintaining part fixed to the top plate, so that the operating wire member is prevented from being deviated from the operating pulley member.
A piece of furniture with a top plate of the present invention , in which: a pair of left and right leg bodies which supports left and right sides of the top plate is configured such that an inner leg column is inserted into and fitted with an outer leg column to allow each leg body to be freely extended and retracted vertically; a height position is configured to be changed by extending and retracting the leg bodies to raise and lower the top plate; and an elevation synchronizing means that synchronizes extending and retracting operations of the leg bodies, the piece of furniture is characterized in that the elevation synchronizing means is constituted with a synchronizing pulley member pivotally attached to a leg column configured to be raised and lowered from among the inner and outer leg columns, and a flexible synchronizing wire member hung on the synchronizing pulley member, the synchronizing wire member is connected to a connecting member fixed to a leg column extending in a vertical direction and installed on a floor surface from among the inner and outer leg columns, and the inner leg column is configured such that a first accommodating portion accommodating a gas spring, which is extended and retracted vertically to assist an extension and retraction of the leg body and fixation of a height position of the leg body, and a second accommodating portion accommodating the connecting member are provided to be spaced apart from each other.
According to this feature, the gas spring accommodated in the first accommodating portion, and the connecting member accommodated in the second accommodating portion, the synchronizing wire member connected to the connecting member, or the synchronizing pulley member hung on the synchronizing wire member are operated without being interfered with each other. Even when the leg column installed on the bottom surface is any one of the inner and outer leg columns, the leg column can be connected to the synchronizing wire member by means of the connecting member extending vertically. Further, the first and second accommodating portions are formed in the inner leg column, the elevation synchronizing means for synchronously raising and/or lowering both left and right side sections of the top plate and the gas spring can be compactly accommodated in the leg body, thereby reducing a weight of the leg body.
The piece of furniture of the present invention is characterized in that a third accommodating portion formed between the first accommodating portion and the second accommodating portion and having a width narrower than those of the first and second accommodating portions is provided in the inner leg column, and the synchronizing pulley member is accommodated in the third accommodating portion.
According to this feature, the gas spring accommodated in the first accommodating portion, the synchronizing pulley member accommodated in the third accommodating portion and the synchronizing wire member hung on the synchronizing pulley member are operated without being interfered with each other. Further, since the third accommodating portion has a narrow width, the first accommodating portion and the second accommodating portion can be spaced apart from each other by the third accommodating portion.
The piece of furniture of the present invention is characterized in that a recessed groove extending vertically is formed at an outer surface of the inner leg column corresponding to the third accommodation portion, and a guide roller is provided at the recessed groove, and
a slide surface extending vertically is formed at an inside of the outer leg column in order for the guide roller to be smoothly contacted.
According to this feature, the guide roller disposed in the recessed groove of the inner leg column smoothly contacts the slide surface in the outer leg column, so that an extending/retracting operation of the leg body can be smoothly performed. The recessed groove can be formed in the inner leg column using a portion where the third accommodating portion having a narrow width is provided, so that the guide roller can be compactly accommodated between the inner leg column and the outer leg column.
The piece of furniture of the present invention is characterized in that a pair of upper and lower guide rollers having axes of rotation orienting the same direction and rotated independently are provided in the recessed groove so that each of the guide rollers smoothly contacts with the slide surface arranged to be opposed.
According to this feature, the pair of guide rollers are disposed between the slide surfaces disposed to be opposed to each other and extending vertically, so that the guide rollers can smoothly contact with the slide surfaces respectively, thereby preventing the leg columns adapted to be raised and/or lowered from being shaken horizontally.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view illustrating a table according to a first embodiment of the present invention.
FIG. 2 is a front view illustrating the table.
FIG. 3 is a left side view illustrating the table.
FIG. 4 is a perspective view illustrating wiring of wire members and disposition of operating parts.
FIG. 5 is a longitudinal cross sectional view illustrating inner structures of a right arm and a leg body, taken along line A-A of FIG. 4.
FIG. 6 is a longitudinal cross sectional view illustrating an inner structure of the leg body, taken along line B-B of FIG. 5.
FIG. 7 is a transversal cross sectional view illustrating the inner structure of the leg body, taken along line C-C of FIG. 5.
FIG. 8 is a partially enlarged view of FIG 5 illustrating a top part of the leg body.
FIG. 9A is a longitudinal sectional view taken along line D-D of FIG. 8.
FIG. 9B is a longitudinal sectional view illustrating a state where a gas spring is being pushed by a pressing member.
FIG. 10 is a perspective view illustrating a lower end portion of an elevation rod.
FIG. 11 is a concept view illustrating a state where a guide roller smoothly contacts a slide surface of a support rod.
FIG. 12A is a plan view illustrating an operating part.
FIG. 12B is a plan view illustrating a state where an operating lever is pulled toward the front side.
FIG. 13A is a longitudinal sectional view taken along line E-E of FIG. 12A.
FIG. 13B is a longitudinal sectional view illustrating a state where the operating lever is pulled to the front side.
FIG. 14 is a concept view illustrating an operating wire member hung on a pulley and a pressing member.
FIG. 15 is a concept view illustrating an elevation synchronizing means.
FIG. 16A is a plan view illustrating an operating part according to a second embodiment of the present invention.
FIG. 16B is a plan view illustrating a state where an operating lever is pulled toward the front side.
FIG. 17A is a longitudinal sectional view taken along line F-F of FIG. 15.
FIG. 17B is a longitudinal sectional view illustrating a state where the operating lever is pulled toward the front side.

MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of a piece of furniture with a top plate according to the present invention will be described.

FIRST EMBODIMENT

A piece of furniture with a top plate according to a first embodiment will be described with reference to FIGS. 1 to 17B. Hereinafter, lower right sides of FIGS. 1 and 4 will be described as a front side (forward) of a table, upper right sides of FIGS. 1 and 4 will be described as a right side of the table 1, right sides of FIGS. 3, 5, 7, 8, 12A, 12B, 13A, 13B, 16A, 16B, 17A, and 17B will be described as a front side (forward) of the table, and a lower side of FIG. 14 will be described as a front side (forward) of the table.
Reference numeral 1 of FIG. 1 denotes a table which is a piece of furniture with a top plate to which the present invention is applied. The table 1 includes one sheet of top plate 2 which is laterally long, and one pair of left and right leg bodies 3 supporting left and right sides of the top plate 2, respectively, and configured to change a height of the top plate 2 by raising and/or lowering the top plate 2.
As shown in FIGS. 2 and 3, each leg body 3 includes a base leg 4 installed on the floor surface to be extended forward and rearward, a support rod 5 (fixed leg column, outer leg column) provided to be erected from a center of the base leg 4, and an elevation rod 6 (movable leg column, inner leg column) inserted into the support rod 5. A top portion of the support rod 5 is opened, and the elevation rod 6 is inserted into the support rod 5 to be raised or lowered freely with respect to the support rod 5.
As shown FIG. 4, arms 7 extending forward and rearward are provided at the top portions of the leg bodies 3, respectively, and attached to the top portions of the elevation rods 6. The left and right arms 7 are connected to each other by two connecting rods 8 provided in parallel in forward and rearward direction. The connecting rods 8 constitute leg columns, and extend substantially linearly between the left and right leg bodies 3. The top plate 2 is attached to top portions of the arms 7 and the connecting rods 8 such that the top plate 2 can be raised as the elevation rods 6 are raised.
Operating parts 9 (operating means) operated by an operator when raising and/or lowering the top plate 2 are attached to a central portion of a lower surface of the top plate 2 (see FIG. 2). The operating parts 9 are spaced apart from each other and attached to two front and rear locations of the top plate 2 which are situated around a front end and a rear end of the top plate 2, so that the operator can operate elevation of the top plate 2 at any place either the front side or the rear side of the table 1 (see FIG. 4).
As will be described below, the operator lifts or lowers the top plate 2 while maintaining a state where an operating lever 10 provided in the operating part 9 is moved horizontally in a direction far away from the top plate 2 to freely change a height of the top plate 2.
Next, internal structures of the left and right leg bodies 3 will be described. Since the internal structures of both of the leg bodies 3 have substantially the same structure where the front and rear sides thereof are formed in a reverse state, the right leg body 3 will be described as an example. FIG. 5 is a cross sectional view taken along line A-A of FIG. 4 and is a longitudinal sectional view viewed from the inner side of the table 1.
As shown in FIG. 5, a connecting member 11 fixed to a base leg 4 is provided to extend vertically on the front side (the right side of the drawing) in an inner part of the elevation rod 6, a gas spring 12 which is extended and retracted vertically is provided on the rear side (the left side of the drawing) in the inner part of the elevation rod 6. Meanwhile, a lower end of the gas spring 12 is fixed to the base leg 4, and a top end thereof is fixed to a lower surface of the arm 7.
A pulley member 13 (synchronizing pulley member) and a synchronizing wire member 14 constituting an elevation synchronizing means to be described below are provided between the connecting member 11 and the gas spring 12. The pulley member 13 is rotated about a rotation axis 61 extending laterally, and is moved vertically by the synchronizing wire member 14.
Next, the gas spring 12 will be described with reference to FIGS. 5 and 8. As shown in FIG. 5, the gas spring 12 has a cylinder 15 encapsulating gas, and a piston rod 16 disposed within the cylinder 15 to repeatedly enter into and exit from the cylinder 15. The gas spring 12 is extended and retracted vertically according to entering and exiting of the piston rod 16, a vertical length of the gas spring 12 may be changed arbitrarily.
As shown in FIG. 8, the piston rod 16 is operated as a push rod 17 provided at a top end of the gas spring 12 is pressed, thus arbitrarily changing the vertical length of the gas spring 12. A nut 18 attached to a location lower than the arm 7 in the piston rod 16 is secured to a lower surface of the arm 7 in a threaded fashion.
Meanwhile, the elevation rod 6 is raised and/or lowered vertically as the vertical length of the gas spring 12 is changed, and a height of the elevation rod 6 is fixed as the vertical length of the gas spring 12 is fixed. Hereinafter, a state where the push rod 17 is pressed and thus the piston rod 16 can be extended and/or retracted will be referred to as an extendable state, and a state where the push rod 17 is released from the pressed state and thus the piston rod 16 is locked (fixed) will be referred to as a fixed state.
Next, a switching means for switching a state of the gas spring 12 between the extendable state and the fixed state will be described with reference to FIGS. 8, 9A, and 9B. FIG. 9A is a cross sectional view taken along line D-D of FIG. 8, and is a longitudinal rear cross sectional view where the leg body 3 is viewed from a rear side of the table 1.
As shown in FIGS. 8 and 9A, a pressing member 19 (switching means, operating member) for pressing the push rod 17 (an operating part) of the gas spring 12 is provided within the arm 7.
The pressing member 19 is pivotally attached to a pivot member 20 attached to the arm 7, and the pressing member 19 fluctuates vertically while taking a pivot shaft 21 extending forward and rearward on a lower side thereof as an axis thereof.
As shown in FIG. 9A, a top end of the pressing member 19 is formed as a wire coupling part 23 to which an operating wire member 22 for fluctuating the pressing member 19 is coupled, and a pressing part 24 for pressing the push rod 17 is formed at a part of a lower end of the pressing member 19 corresponding to the gas spring 12.
The operating wire member 22 has an operating wire 25 (operating wire member, the switching synchronizing means) and a resin tubular member 26, and the operating wire 25 is inserted into and passes through the tubular member 26 to be smoothly moved in a direction where the operating wire 25 extends within the tubular member 26. The operating wire member 22 is fixed to the arm 7 by a fixing part 27 formed at an end of the tubular member 26.
In the table 1 according to the present embodiment, two operating wire members 22 are provided on the front and rear sides. The pressing members 19 are provided in the left and right arms 7 respectively, and one operating wire member 22 connects the pressing members 19 to each other (see FIGS. 4 and 14). The front and rear operating wire members 22 are connected to the same pressing member 19, and the front and rear operating wire members 22 are disposed substantially in parallel to each other near the pressing member 19.
The operating wire 25 is provided to be longer than a length of the tubular member 26, and the operating wire 25 is exposed to an end of the operating wire member 22. Tips of the operating wires 25 are stopped by coupling clasps 28 respectively, and the coupling clasps 28 are coupled to wire coupling parts 23 of the pressing members 19. The wire coupling parts 23 are formed on the front and rear sides of the pressing member 19, and the front and rear operating wires 25 and 25 are coupled to the front and rear wire coupling parts 23, respectively (see FIG. 8). In the pressing member 19, the front and rear wire coupling parts 24 (connecting portions) are spaced apart from each other on the front and rear sides, and the pulley member 43 to be described below can be disposed between the front and rear wire coupling parts 23, that is, between the two operating wire members 22.
As shown in FIG. 9B, if the operating wire 25 is pulled inward, the pressing member 19 fluctuates and the pressing part 24 lowers. Then, the push rod 17 of the gas spring 12 is pressed so that the piston rod 16 turns into an extendable state where the gas spring 12 can be extended and retracted.
Meanwhile, if the gas spring 12 turns into an extendable state, the piston rod 16 is lifted by a pressing force of the gas in the gas spring 12 so that the arm 7 and the top plate 2 are pushed upward to allow even a heavy top plate 2 to be easily lifted by the operator.
If a state where the operating wire 25 is pulled is released, the pressing part 24 is pushed upward by the push rod 17 and thus the pressing 19 fluctuates and returns. The piston rod 16 is locked to be in a fixed state. Accordingly, the extendable state and the fixed state are switched therebetween. In order to allow the pressing member 19 to easily return, a pressing means such as a spring may be provided at a portion of the pivot shaft 21 of the pivot member 20.
Next, the operating part 9 will be described with reference to FIGS. 12A to 13B. Since the operating parts 9 provided two locations at the front and rear sides of the top plate 2 have the same structure, the operating part 9 provided on the front side will be described as an example. As shown in FIG. 12A, a fixed member 29 which is fixed to the top plate 2 and a movable member 30 which is movable horizontally are provided in the operating part 9. The operating lever 10 for moving the movable member 30 by the operator is provided on the front side of the movable member 30.
The fixed member 29 has a rectangular shape in a plan view, and four corner portions of the fixed member 29 are secured to the top plate 2 in a threaded fashion. Two maintaining parts 31 for maintaining the operating wire member 22 are formed at a rear end of the fixed member 29. The movable member 30 combined with the top side of the fixed member 29 has a front portion whose a left and right width is smaller than that of a rear portion thereof.
Two long holes 32 extending forward and rearward are formed on the front side and rear side of the movable member 30. Bolts 33 inserted into and passing through the long holes 32 from the top side thereof are fixed to the fixed member 29, and when the movable member 30 is situated at a normal location shown in FIG. 12A, the bolts 33 are situated at front ends of the long holes 32 respectively.
A substantially semicircular pulley disposing part 34 is formed at a rear side of the movable member 30. A pulley 35 (a movable member, a switching synchronizing means, and an operating pulley member) to which a substantially central portion of the operating wire member 22 is coupled is attached to the pulley disposing part 34.
As shown in FIG. 13A, a hole portion 36 formed in the pulley disposing part 34 of the movable member 30, a central hole 37 of the pulley 35, and a hole portion 39 of a pulley pivoting member 38 attached to the movable member 30 are formed at locations corresponding to one another. The pulley 35 is configured to be rotated about a rotation axis 62 thereof extending vertically between the pulley pivoting member 38 and the pulley disposing part 34.
In the maintaining part 31 of the fixed member 29, a fixed part 40 provided at an end of the tubular member 26 of the operating wire member 22 is maintained and the operating wire 25 exposed from the fixed part 450 is coupled to the pulley 35. A circumferential surface on the front side of the pulley 35 serves as a contact surface 41 on which the operating wire 25 of a substantially central portion of the operating wire member 22 is smoothly moved.
A vicinity of a portion of the operating wire member 22 coupled to the pulley 35 is maintained by the maintaining part 31, so that the operating wire 25 remains hung on the pulley 35 to be able to be prevented from being deviated from the pulley 35.
As shown in FIGS. 12B and 13B, if the operating lever 10 is pulled forward and thus the movable member 30 is moved to a front location, the operating wire 25 is smoothly moved in the tubular member 26 so that the operating wire 25 coupled to the pulley 35 is pulled forward.
Next, an operation during operation of the operating part 9 will be described with reference to the concept view of FIG. 14. Since the pressing members 19 of the left and right leg bodies 3 are connected to each other though the operating wire member 22 and the operating parts 9 are provided at substantially central portions of the front and rear ends of the top plate 2, a substantially central portion of the operating wire member 22 is smoothly moved on the contact surfaces of the pulleys 35 of the operating parts 9 to be pulled.
Accordingly, even when there is an error in lengths of the operating wire members 22 from the movable member 30 to the left and right pressing members 19, the error is offset as the operating wire members 22 are smoothly moved through the contact surface 41 of the pulleys 35 in conjunction with rotation of the pulleys 35. The operating wire members 22 may be spaced part from the contact surfaces 41 of the pulleys 35. That is, the operating wire members 22 may be moved relative to the pulleys 35 and the movable members 30.
When the operator pulls the front operating lever 10 forward, the operating wire 25 coupled to the pulley 25 is pulled forward and left and right ends of the operating wire 25 are moved inward. The pressing members 19 within the left and right leg bodies 3 are operated at the same time, and thus the extendable state and the fixed state of the gas springs 12 can be switched into each other at the same time (see FIGS. 9A and 9B)
Next, the elevation synchronizing means for synchronizing extendable and retractable operations of the left and right leg bodies 3 will be described with reference to FIGS. 5 to 8 and 15. The elevation synchronizing means for synchronizing vertical movement of the elevation rod 6 is provided in the table 1 according to the present embodiment. FIG. 6 is a cross sectional view taken along line B-B of FIG. 5 and is a longitudinal rear cross sectional view when the right leg body 3 is viewed from the rear side of the table 1.
The elevation rods 6 disposed on the left and right sides can be moved vertically by the same distance respectively by means of the elevation synchronizing means. Thus, a horizontal state of the top plate 2 can be maintained when the height of the top plate 2 is changed.
As shown in FIGS. 5 and 6, the pulley member 13 provided between the gas spring 12 and the connecting member 11 inside the elevation rod 6 is rotated about the rotation axis 61 extending leftward and rightward to be moved vertically by the synchronizing wire member 14.
A pulley member 43 (a synchronizing pulley member) where two front and rear pulleys 42 and 42' are connected is provided in the arm 7, and the pulley member 43 is rotated about a rotation axis 63 extending forward and rearward and the front pulley 42 and the rear pulley 42' can be rotated independently.
A 'U' shaped bracket 44 when viewed from a side is provided outside the pulley member 43 (see FIG. 8), and the pulley member 43 is secured to the arm 7 through the bracket 44 (see FIG. 6). The pulley member 43 is disposed more inside than the pressing member 19, so that the pressing member 19 does not collide with the pulley member 43 even when the pressing member 19 fluctuates (see FIGS. 9A and 9B).
The synchronizing wire member 14 is coupled to the pulley members 13 and 43 to be hung on lower sides of the left and right leg bodies 3 and the top plate 2. As shown in FIG. 8, a connecting clasp 45 is provided in the vicinity of the connecting member 11 of the synchronizing wire member 14, and the synchronizing wire member 14 is connected to a top end of the connecting member 11 through the connecting clasp 45.
As shown in FIG. 5, a stopper 46 is provided at a substantially intermediate portion of the connecting member 11. A stopper contact member 47 is provided on a lower surface of the elevation rod 6, and lifting of the elevation rod 6 stops at a location where the stopper contact member 47 contacts the stopper 46 (see FIG. 10).
The synchronizing wire member 14 is hung in a U-shaped form from the front pulley 42 of the pulley member 43 toward the rear pulley 42' through the pulley member 13. The synchronizing wire member 14 extending from the pulley member 43 of the right arm 7 extends toward the left arm 7, and is integrally formed hung on the left arm 7 and the leg body 3.
An operation during elevation of the top plate 2 will be described with reference to a concept view of FIG. 15. The elevation synchronizing means includes pulley members 13 and 43 and a synchronizing wire member 14 connected to the connecting member 11. As mentioned above, the pulley members 13 and 43 are pivotally attached to the elevation rod 6 to be raised and/or lowered together with the elevation rod 6.
As shown in FIG. 15, the synchronizing wire member 14 hung on one pulley 42 of the upper pulleys 42 and 42' will be described as a synchronizing wire member 14a and the synchronizing wire member 14 hung on the other pulley 42' will be described as a synchronizing wire member 14b in the following.
For example, when the elevation rod 6 on the right side of the drawing is lifted, the right pulley member 43 is lifted. Since the synchronizing wire member 14a is fixed to the connecting member 11 through the connecting clasp 45, the right pulley 42 is pulled and lifted so that the left pulley member 13 is moved in conjunction with the synchronizing wire member 14a and is lifted by the same distance as the movement distance of the right pulley 42.
Similarly, when the elevation rod 6 on the left side of the drawing is lifted, the left pulley member 43 is also lifted. Since the synchronizing wire member 14b is fixed to the connecting member 11 through the connecting clasp 45, the left pulley 42' is pulled and lifted so that the right pulley member 13 is moved in conjunction with the synchronizing wire member 14b and is lifted by the same distance as the movement distance of the left pulley 42'.
In this way, since the synchronizing wire member 14a and the synchronizing wire member 14b are operated at the same time to influence each other, there is no possibility of lifting of only one of the left and right elevation rods 6, 6 in advance occurs. That is, the left and right elevation rods 6 and 6 can be synchronized with certainty to be lifted.
Even when the left and right elevation rods 6 and 6 drop, the left elevation rod 6 and the right elevation rod 6 are operated to lower in conjunction with each other at the same time by the same distance. In this way, since the extensions and retractions of the left and right elevation rods 6 and 6 are synchronized, the left and right elevation rods 6 and 6 and the top plate 2 can be raised and/or lowered integrally.
That is, when the height of the top plate 2 is changed in a synchronized extensions and retractions of both of the leg bodies 3 by the elevation synchronizing means, the top plate 2 can be raised and/or lowered while maintaining the horizontal state thereof without distorting the height of the top plate 2 on the left and right sides.
Next, disposition of the gas spring 12, the connecting member 11, and the pulley member 13 in the leg body 3 will be described with reference to FIGS. 7 and 10. The right side of FIG. 7 will be described as the front side.
As shown in FIG. 7, a first accommodating portion 48 in which the gas spring 12 is accommodated is formed at a rear side of the elevation rod 6 inserted into the support rod 5, and a second accommodating portion 49 in which the connecting member 11 is accommodated is formed at a front side of the elevation rod 6. A third accommodating portion 50 in which the pulley member 13 is accommodated is formed between the first accommodating portion 48 and the second accommodating portion 49.
In this way, the gas spring 12 accommodated in the first accommodating portion 48, the pulley member 13 accommodated in the third accommodating portion 50, and the synchronizing wire member are adapted to be operated without being interfered with each other.
The third accommodating portion 50 has a left and right width narrower than those of the first and second accommodating portions 48 and 49, and a recessed groove 51 extending vertically is formed at a portion on the outer surface of the elevation rod 6 corresponding to the third accommodating portion 50.
As shown in FIG. 7, a plurality of guide rollers 52 rotated about a rotation axis 64 extending leftward and rightward are attached to four surfaces including the outer surfaces on the front and rear sides of the elevation rod 6 and the left and right recessed grooves 52. A pair of upper and lower guide rollers 52, 52, of the guide rollers 52, is rotated independently, and the pair of upper and lower guide rollers 52, 52 constitutes one roller part 53.
As shown in FIG. 10, the respective guide rollers 52, 52 of the roller part 53 are disposed to be displaced horizontally to some degree, and in the present embodiment, roller parts 53 are provided at two upper and lower locations of each of the front, rear, left and right surfaces of the elevation rod 6 (see FIGS. 5 and 6).
As shown in FIG. 7, grooves 54 are formed at portions of the support rod 5 corresponding to the guide rollers 52, and the opposing surfaces of the grooves 54 are formed as slide surfaces 55 which the guide rollers 52 contact smoothly. Each pair of upper and lower guide rollers 52 smoothly contact one slide surface 55 and another slide surface 55 respectively.
As shown in the concept view of FIG. 11, the guide roller 52 on the right side of the drawing smoothly contacts the right slide surface 55, and the guide roller 52 on the left side of the drawing smoothly contacts the left slide surface 55. Accordingly, the elevation rod 6 can be raised and/or lowered without being shaken horizontally.
When the elevation rod 6 is lifted, the right guide roller 52 is rotated clockwise and the left guide roller 52 is rotated counterclockwise. Accordingly, an elevation operation of the elevation rod 6 can be smoothly performed.
When the elevation rod 6 is lowered, the right guide roller 52 is rotated counter-clockwise, and the left guide roller 52 is rotated clockwise (not shown).
Since the recessed groove 51 is formed using a portion of the elevation rod 6 where the third accommodating portion 50 is provided, the guide roller 52 can be compactly accommodated between the elevation rod 6 and the support rod 5.
Next, an operation of the operating part 9 by the operator to raise and/or lower the top plate 2 will be described. If the operator pulls the operating lever 10 of the operating part 9 in a forward direction to move the movable member 30 to a front location, a substantially central portion of the operating wire 25 coupled to the pulley 35 is moved forward (see FIG. 12B), and both ends of the operating wire member 22 are moved to a central side equally (see FIG. 14).
The left and right pressing members 19, 19 to which the operating wire 25 at an end of the operating wire member 22 is coupled are fluctuated, and the pressing part 24 is lowered to press the push rod 17 of the gas spring 12 simultaneously (see FIG. 9B). Then, the left and right gas springs 12, 12 can be extended and retracted at the same time to make the top plate 2 elevatable.
In this way, since the left and right gas springs 12, 12 are switched into an extendable state at the same time, one of the gas springs 12 is prevented from being switched in advance and thus the top plate 2 is prevented from being tilted, due to unevenness of the pressing forces of the gas springs 12, 12.
When the operator lifts the top plate 2, the top plate 2 is pushed upward to be lifted while the gas spring 12 remains extended, that is, the operating lever 10 is being pulled. In this case, since an upward force is applied to the piston rod 16 by the gas in the gas spring 12, even a heavy top plate 2 can lifted easily.
Since the elevation synchronizing means constituted with the pulley members 13 and 43 and the synchronizing wire member 14 is provided, a height of the top plate 2 can be prevented from being distorted in the left and right sides. Since the operating part 9 is provided at a substantially central portion of the top plate 2, the force applied to the top plate 2 by the operator can be equally applied to the left and right leg bodies.
When the top plate 2 is moved to an arbitrary location and the operator releases a hand from the operating lever 10 to return the movable member 30 to a normal location, a substantially central portion of the operating wire 25 coupled to the pulley 35 is moved rearward and thus an end of the operating wire member 22 is equally moved outward.
The left and right pressing members 19, 19 to which the operating wire 25 at the end of the operating wire member 22 is coupled are fluctuated and the pressing part 24 is lifted, thereby releasing the pressings of the push rods 17 of the gas springs 12 simultaneously. The left and right gas springs 12, 12 simultaneously become a fixed state to fix a location of the top plate 2.
Meanwhile, when the operator lowers the top plate 2, the top plate 2 is pushed downward to be lifted while the gas spring 12 remains extended state, that is, the operating lever 10 is being pulled.
When the top plate 2 is moved to an arbitrary location and the operator releases a hand from the operating lever 10 to return the movable member 30 to a normal location, the operating wire 25 coupled to the pulley 35 is moved rearward and thus an end of the operating wire member 22 is moved outward at the same time.
When the left and right pressing members 19, 19 are fluctuated simultaneously and the pressing part 24 is lifted, the pressings of the push rods 17 of the gas springs 12 are released simultaneously. The left and right gas springs 12, 12 simultaneously becomes a fixed state to fix a location of the top plate 2.
As mentioned above, in the table 1 according to the present embodiment, each leg body 3 has a support rod 5 installed on the floor surface, an elevation rod 6 supported by the support rod 5 to be raised and/or lowered, a gas spring 12 for assisting elevation of an elevation rod 6 and fixing a height of the elevation rod 6 while being extended and retracted vertically, and a pressing member 19 for switching an extendable state and a fixed state of the gas spring 12, and a switching synchronizing means for simultaneously operating the pressing members 19 when a operating part 9 provided in a top plate 2 to operate the pressing member 19 is operated is provided. Therefore, a vertical location of the top plate 2 can be adjusted by an operation of the gas spring 12, while even a heavy top plate 2 can be easily raised and/or lowered by two gas springs 12 of the left and right leg bodies 3. Further, since the extendable state or fixed state of the the left and right gas springs 12 are simultaneously switched by the switching synchronizing means for simultaneously operating the pressing members 19, one of the gas springs 12 is prevented from being switched in advance and to prevent the tilting of the top plate 2.
A switching synchronizing means has a configuration in which the pressing members 19 is allowed to operate a push rod 17 of each gas spring 12, a flexible operating wire member 22 connecting the pressing members 19 to each other is provided, and a movable member 30 for moving a substantially central portion of the operating wire member 22 in a direction other than a direction in which the operating wire member 22 extends is provided in a operating part 9. Accordingly, when the flexible operating wire member 22 is moved by the movable member 30 in the direction other than the direction in which the operating wire member 22 extends when the operating part 9 is operated, left and right ends of the operating wire member 22 connected to the pressing members 19 are equally moved in the direction in which the operating wire member 22 extends and thus the push rods 17 of the gas springs 12 can be operated simultaneously. As such, the switching synchronizing means can be provided in a simple configuration in which the pressing member 19, the operating wire member 22, and the movable member 30 are included.
The movable member 30 can pull a substantially central portion of the operating wire member 22 and the substantially central portion of the operating wire member 22 can smoothly move on a contact surface 41 of the movable member 30. Accordingly, when the operating part 9 is operated, both left and right ends of the operating wire member 22 are moved toward the substantially central portion of the operating wire member 22 so that both the left and right ends of the operating wire member 22 are moved equally. Even when there is an error in the lengths of the operating wire members 22 from the movable member 30 to the pressing members 19, the error can be offset by allowing the operating wire members 22 to smoothly move on the contact surfaces 41 of the movable members 30.
The substantially central portion of the operating wire member 22 is coupled to a pulley 35 of the movable member 30 so that the vicinity of a portion of the operating wire member 22 coupled to the pulley 35 is maintained in a maintaining part 31 fixed to the top plate 2 to be able to smoothly move. Accordingly, even when there is an error in the lengths of the operating wire members 22 from the movable member 30 to the pressing members 19, the error can be offset by allowing the operating wire member 22 to be moved due to rotation of the pulley 35 in a direction in which the operating wire member 22 extends. Further, the vicinity of a portion of the operating wire member 22 coupled to the pulley 35 is maintained by the maintaining part 31 fixed to the top plate 2, thereby preventing the operating wire member 22 from being deviated from the pulley 35.
In the table 1 according to the present exemplary embodiment, the elevation synchronizing means for synchronizing an elevation operation of both leg bodies 3 is constituted with pulley members 13, 43 pivotally attached to elevation rods 6 of one of inner and outer leg columns, which can be raised and/or lowered, and a flexible synchronizing wire member 14 hung on the pulley members 13, 43. The synchronizing wire member 14 is connected to a connecting member 11 fixed to a support rod 5 of one of the inner and outer leg columns, and is extended vertically. A first accommodating portion 48 accommodating a gas spring 12 extending and retracting vertically to assist extension and retraction of the leg body 3 and fix a height of the leg body 3, and a second accommodating portion 49 accommodating the connecting member 11 are provided in the elevation rod 6 to be spaced apart from each other. Accordingly, the gas spring 12 accommodated in the first accommodating portion 48, and the connecting member 11 accommodated in the second accommodating portion 49, the synchronizing wire member 14 connected to the connecting member 11, or the pulley members 13 and 43 on which the synchronizing wire member 14 is hung are operated without being interfered with each other, and the synchronizing wire member 14 can be connected to the support rod 5 by the connecting member 11 extending vertically even when the support rod 5 is any one of the inner and outer leg columns. Further, since the first and second accommodating portions 48, 49 are formed in the elevation rod 6, the elevation synchronizing means for synchronously raising and/or lowering left and right sides of the top plate and the gas spring 12 can be compactly accommodated in the leg body 3, achieving lightness of the leg body 3.
A third accommodating portion 50 whose width is narrower than those of the first and second accommodating portions 48 and 49 is formed between the first accommodating portion 48 and the second accommodating portion 49 of the elevation rod 6. The pulley member 13 is accommodated in the third accommodating portion 50, so that the gas spring 12 accommodated in the first accommodating portion 48, the pulley member 13 accommodated in the third accommodating portion 50, and the synchronizing wire member 14 hung on the pulley member 13 are operated without being interfered with each other. Further, since the third accommodating portion 50 has a narrow width, the first accommodating portion 48 and the second accommodating portion 49 can be spaced apart from each other by the third accommodating portion 50.
A recessed groove 51 extending vertically is formed at a portion corresponding to the third accommodating portion 50 on the outer surface of the elevation rod 6, while a guide roller 52 is provided in the recessed groove 51. Further, a slide surface 55 extending vertically for smooth contact of the guide roller 52 is formed in the support rod 5 and the guide roller 52 disposed in the recessed groove 51 of the elevation rod 6 smoothly contacts the slide surface 55 in the support rod 5. Accordingly, an extending/retracting operation of the leg body 3 can be smoothly performed and the recessed groove 51 can be formed in the elevation rod 6 using a portion where the third accommodating portion 50 having a narrow width is provided, so that the guide roller 52 can be compactly accommodated between the elevation rod 6 and the support rod 5.
Two pairs of upper and lower roller parts 53 independently rotated about rotation axes 64 oriented toward the same direction are provided in the recessed groove 51 to smoothly contact the slide surfaces 55 on which the guide rollers 52 are disposed to be opposed to each other, respectively. Accordingly, the pair of upper and lower roller parts 53 are disposed between the slide surfaces 55 disposed to be opposed to each other and extending vertically so that the guide rollers 52 smoothly contact the slide surfaces 55, the elevatable leg columns which can be raised and/or lowered without being shaken horizontally.

SECOND EMBODIMENT

Next, a piece of furniture with a top plate according to a second embodiment of the present invention will be described with reference to FIGS. 16A to 17B. FIGS. 16A to 17B are views illustrating a operating part 9' according to the second embodiment of the present invention, and the configuration except for the operating part 9' is the same as that of the first embodiment and thus a description thereof will be omitted.
As shown in FIGS. 16A to 17B, a fixed member 29' fixed to the top plate 2 and a movable member 30' movable horizontally are provided in the operating part 2, and a operating lever 10' for moving the movable member 30' by an operator is provided on the front side of the movable member 30'.
The fixed member 29' having a rectangular shape when viewed from the top is secured to the top plate 2 in a threaded fashion, and the movable member 30' is disposed above the fixed member 29'. As in the first exemplary embodiment, a long hole 32' extending forward and rearward is formed at a front side of the movable member 30' so that a bolt 33' inserted into and passing through the long hole 32' from the top side is fixed to the fixed member 29'. An operating wire 25 is coupled to a pulley 35 provided in the movable member 30' on a rear side so that the movable member 30' is moved to a front side through operation of the operating lever 10'.
As shown in FIG. 17A, a front portion of the operating lever 10' is formed with a plate portion, and an pulling portion 57 for pulling the movable member 30' is provided at a rear portion thereof. The pulling portion 57 has a substantially triangular shape when viewed from a side, and a lever pivot portion 58 at a top end thereof is pivotally attached to a lever attaching portion 59 provided on a lower surface of the top plate 2.
A pivot shaft 60 is provided at a lower portion of the pulling portion 57 to be attached pivotally at a rear side of the movable member 30'. When the movable member 30' is situated at a normal location shown in FIG. 17A, an end of the plate portion 56 of the operating lever 10' orients downward.
As shown in FIG. 17B, when the operator pulls the plate portion 56 of the operating lever 10' upward, the operating lever 10' is fluctuated about the lever pivoting portion 58 and the pivot shaft 60 is moved forward to move the movable member 30' to a front location.
As a substantially central portion of the operating wire member 22 coupled to the pulley 35 is moved forward, as mentioned above, left and right pressing members 19, 19 connected by the operating wire member 22 are operated simultaneously and left and right gas springs 12, 12 are switched into an extendable state.
When the operator releases a hand from the manipulator lever 10' and the movable member 30' returns to a normal location, the operating wire 25 coupled to the pulley 35 is moved rearward and an end of the operating wire member 22 is equally moved outward so that the gas spring 12 is switched into a fixed state.
Meanwhile, since a fluctuating direction of the operating lever 10' and a direction of raising the top plate 2 are the same in the operating part 9' according to the second embodiment, when the operator operates the operating lever 10' to adjust a height of the top plate 2, the operator can raise the top plate 2 as it is while gripping a corner of the top plate 2 together with the operating lever 10', such that a height of the top plate 2 can be easily adjusted.
Although the embodiments of the present invention have been described with reference to the drawings, a detailed configuration of the present invention is not limited to the embodiments and may be modified or added without departing from the gist of the present invention.
For example, although a table has been exemplified as a piece of furniture with a top plate to which the present invention is applied in the embodiments, any piece of furniture with a top plate which can be raised and/or lowered may be a desk, and the present invention can be applied to a shelf or other items.
Although the gas spring 12 is operated by pressing the push rod 17 (operating part) in the exemplary embodiments, an operation type of the push rod (operation part) is not limited to the embodiments and a configuration where the gas spring 12 is operated by horizontally moving the push rod (operating part) may be adopted.
Although a pulley 35 having a contact surface 41 on which the operating wire member 22 is smoothly moved is used in the embodiments, it will be sufficient if a contact surface which is a circumferential surface on the front side is formed. Otherwise, the pulley 35 may be replaced by a member having a substantially semicircular shape when viewed from the top.
Although two operating parts are provided at both front and rear sides of the top plate 2 of the table 1 in the embodiments, one operating part 9 may be provided at one of the front and rear sides.
Although two operating parts are provided at both front and rear sides of the top plate 2 of the table 1 in the embodiments, one operating part 9 may be provided at one of the front and rear sides.
Although the elevation rod 6 is inserted into and fitted with the support rod 5 installed on the floor surface in the embodiments, the support rod 5 may be inserted into and fitted with the elevation rod 6 while the elevation rod 6 serves as an outer leg column and the support rod 5 serves as an inner leg column.

DESCRIPTION OF REFERENCE NUMERALS

1: table (furniture with a top plate)
2: top plate
3: leg body
5: support rod (fixed leg column, outer leg column)
6: elevation rod (movable leg column, inner leg column)
9, 9': operating part (operating means)
11: connecting member
12: gas spring
13: pulley member (synchronizing pulley member)
14: synchronizing wire member (synchronizing wire member)
17: push rod (operating part)
19: pressing member (switching means, operating member)
25: operating wire (operating wire member, switching synchronizing means)
30, 30': movable member
31: maintaining part
35: pulley (movable member, switching synchronizing means, operating pulley member)
41: contact surface
42, 42': pulley
43: pulley member
48: first accommodating portion
49: second accommodating portion
50: third accommodating portion
51: recessed groove
52: guide roller
55: slide surface
64: rotation axis

Claims

A piece of furniture with a top plate, the piece of furniture comprising:
a top plate; and

a pair of left and right leg bodies which supports left and right sides of the top plate,

wherein a height position is changeable by raising or lowering the top plate,

the piece of furniture is characterized in that

each of the leg bodies includes a fixed leg column installed on a floor surface, a movable leg column supported by the fixed leg column to be raised and lowered, a gas spring which is extendable and retractable vertically to assist raising and lowering of the movable leg column and fixation of a height position of the movable leg column, and a switching means which switches an extendable state and a fixed state of the gas spring, and

an operating means which operates the switching means is provided in the top plate, and a switching synchronizing means is provided to simultaneously operate each of the switching means when the operating means is operated.
The piece of furniture of claim 1, characterized in that
the switching means serves as an operating member which operates an operating part of the gas spring and is provided with a flexible operating wire member which connects each of the operating member, and
the switching synchronizing means is configured by providing a movable member which moves a substantially central portion of the operating wire member in a direction other than a direction in which the flexible operating wire member extends.
The piece of furniture of claim 2, characterized in that
the movable member is adapted to pull the substantially central portion of the operating wire member, and the substantially central portion of the operating wire member smoothly moves on a contact surface of the movable member.
The piece of furniture of claim 2 or 3, characterized in that
the substantially central portion of the operating wire member is coupled to an operating pulley member of the movable member, and a vicinity of a portion of the operating wire member coupled to the operating pulley member is maintained to smoothly move on a maintaining part fixed to the top plate.
A piece of furniture with a top plate, in which:
a pair of left and right leg bodies which supports left and right sides of the top plate is configured such that an inner leg column is inserted into and fitted with an outer leg column to allow each leg body to be freely extended and retracted vertically;

a height position is configured to be changed by extending and retracting the leg bodies to raise and lower the top plate; and

an elevation synchronizing means that synchronizes extending and retracting operations of the leg bodies,

the piece of furniture is characterized in that

the elevation synchronizing means is constituted with a synchronizing pulley member pivotally attached to a leg column configured to be raised and lowered from among the inner and outer leg columns, and a flexible synchronizing wire member hung on the synchronizing pulley member,

the synchronizing wire member is connected to a connecting member fixed to a leg column extending in a vertical direction and installed on a floor surface from among the inner and outer leg columns, and

the inner leg column is configured such that a first accommodating portion accommodating a gas spring, which is extended and retracted vertically to assist an extension and retraction of the leg body and fixation of a height position of the leg body, and a second accommodating portion accommodating the connecting member are provided to be spaced apart from each other.
The piece of furniture of claim 5, characterized in that
a third accommodating portion formed between the first accommodating portion and the second accommodating portion and having a width narrower than those of the first and second accommodating portions is provided in the inner leg column, and the synchronizing pulley member is accommodated in the third accommodating portion.
The piece of furniture of claim 6, characterized in that
a recessed groove extending vertically is formed at an outer surface of the inner leg column corresponding to the third accommodation portion, and a guide roller is provided at the recessed groove, and
a slide surface extending vertically is formed at an inside of the outer leg column in order for the guide roller to be smoothly contacted.
The piece of furniture of claim 7, characterized in that
a pair of upper and lower guide rollers having axes of rotation orienting the same direction and rotated independently are provided in the recessed groove so that each of the guide rollers smoothly contacts with the slide surface arranged to be opposed.