GB2259447A

GB2259447A - Caster support structure for movable table

Info

Publication number: GB2259447A
Application number: GB9219287A
Authority: GB
Inventors: Ryokichi Yamazaki
Original assignee: Kotobuki and Co Ltd
Current assignee: Kotobuki and Co Ltd
Priority date: 1991-09-13
Filing date: 1992-09-11
Publication date: 1993-03-17
Also published as: GB9219287D0; DE4230381A1

Abstract

A caster support structure is used in a movable table (10) having a foldable top plate (12) at its upper end and front and rear paired casters (16a, 16b) at its lower end. At least rear paired casters (16b) are vertically movably provided to the lower end, and are interconnected with the top plate by a link (58) and levers (32, 40, 46) so that they project downwardly and retract upwardly upon the location of the plate at its vertically folded position and horizontal position, respectively. At the retracted position, antiskid members (18) attached to the rear ends stand on a floor in place of the retracted casters. <IMAGE>

Description

1 - "CASTER SUPPORT STRUCTURE AND MOVABLE TABLE HAVING THE SAME'R The

present invention relates to a caster support structure and a movable table having the same and, more particularly, to a movable table having a foldable top plate.

Movable tables of this type are mainly used at an assembly hall, a hall, a conference room, and the like and can be easily arranged and moved to allow quick set- ting in accordance with the number of participants and a purpose of a conference or meeting or assembly or gathering, etc. when a movable table is not needed, its top plate can be folded to minimize the space required for storing the movable table.

When a conventional movable table is arranged at a desired place, wheel rotation stoppers provided to its several casters are operated to prevent it from moving out of the desired place. However, such a conventional wheel rotation stopper is small and does not have suffi- cient performance. When a large force is applied to the movable table with the wheel rotation stoppers being operated, wheels of the casters are rotated against the resistance of the wheel rotation stoppers to move the movable table. In some cases, the wheel rotation stoppers are released to cause an abrupt large movement of the movable table.

A movable table which solves the above described 2 drawbacks of the conventional wheel rotation stoppers is also recently used. In the recent movable table, no wheel rotation stoppers are provided to the casters, the casters are mounted to a lower end portion of a plate support structure member of the movable table to be retractable, and caster operating lever means is provided to the plate support structure member to selectively move the casters between retracted positions and projecting positions. When the caster operating lever means is operated to move the casters to the retracted positions, the lower portion of the plate support structure member directly contact a floor to cause a large friction with the floor in order to prohibit the movable table from moving. When the caster operating lever means is operated to move the casters to the projecting positions, the wheels of the casters are arranged between the lower end portion of the support structure member and the floor in order to facilitate movement of the movable table.

In the conventional movable table of this type, however, a large force is undesirably needed to operate the caster operating lever means. This is because the weight of the movable table incorporating the retractable casters and the caster operating lever means is large, and because, when the casters are moved from the retracted positions to the projecting positions, the movable table must be moved upward by a distance corresponding to the projecting height of each caster against substantially the total weight of the movable table. In addition, a comparatively large force is required to start movement of the casters from the stable projecting positions to the retracted positions. For these reasons, it is difficult for a female, a child, and an aged person to operate the caster operating lever means.

when the movable table is moved again from a predetermined position immediately after it is temporarily stopped at the predetermined position by setting the casters at the retracted positions, if the moving distance is small, people tend to avoid the cumbersome operation of the caster operating lever means and move the movable table by manually lifting it. This manually is moving operation also requires a large force.

The present invention has been derived from the above situations, and an object of the present invention is to provide a caster support structure which can reliably stop a movable table against a large force applied thereto and requires a small force for an operation to move casters between retracted and projecting positions, and a movable table having such a caster support structure.

In order to achieve the object described above, according to the present invention, there is provided a caster support structure, which is provided to a movable table comprising a support structure member extending substantially vertically, a top plate coupled to an upper end portion of the support structure member to be pivotal between a substantially horizontal position and a substantially vertical folded position, and caster means, disposed at positions near front and rear ends of a lower end portion of the support structure member, for supporting the support structure member, and which supports the caster means at positions near the front and rear ends of the support structure member, the caster support structure comprising: caster movably supporting means for supporting one of the caster means at the positions near the front and rear ends to move the above described one of the caster means between a projecting position at which the above described one of the caster means projects from a corresponding one of positions near the front and rear ends and a retracted position at which the above described one of the caster means is retracted and stored in the corresponding one of the positions near the front and rear ends; and interconnecting means, interconnecting the top plate with the caster movably supporting means, for moving the above described one of the caster means from the projecting position to the retracted position when the top plate pivots from the folded position to the horizontal position, and for movina the above described one of the caster means from the retrac-Led position to the projecting position when the top plate - 5 pivots from the horizontal position to the folded position.

is According to the present invention, there is also provided a movable table comprising: a support structure member extending substantially vertically; a top plate coupled to an upper end portion of the support structure member to be pivotal between a substantially horizontal position and a substantially vertical folded position; caster means, disposed at positions near front and rear ends of a lower end portion of the support structure member, for supporting the support structure member; caster movably supporting means for supporting one of the caster means at the corresponding one of the positions near the front and rear ends to move the above described one of the caster means between a projecting position, at which the above described one of the caster means projects from the corresponding one of the positions near the front and rear ends, and a retracted position, at which the above described one of the caster means is retracted and stored in the corresponding one of the positions near the front and rear ends; and interconnecting means, interconnecting the top plate with the caster movably supporting means, for moving the above described one of the caster means from the pro- jecting position to the retracted position when the top plate pivots from the folded position to the horizontal position, and for moving the above described one of the 6 caster means from the retracted position to the projecting position when the top plate pivots from the horizontal position to the folded position.

In the caster support structure and the movable table according to the present invention which are char acterized by being constructed as described above, by setting the caster means at the retracted position, the movable table can reliably stop against a large force applied thereto. In addition, since the caster means on the caster movably supporting means can be moved between the retracted position and the projecting position by utilizing, through the interconnecting means, the pivotal movement of the top plate between the horizontal position and the folded position, the force needed to operate the caster means to move between the retracted position and the projecting position can be small.

Assume that only one caster means can be movable between the projecting position and the retracted position. In this case, when the movable table is moved again from a predetermined position immediately after it is temporarily stopped at the predetermined position by setting this one caster means at the retracted position, the movable table can be easily moved with a small force and without pivoting the top plate from the horizontal position to the folded position to move the caster means from the retracted position to the projecting position, 1 if the moving distance is small.

That is, while only a portion of the support structure member corresponding to the above described one caster means set at the retracted position is manually lifted, a portion of the support structure member corre sponding to the other non-retractable caster means is supported on a floor with the wheel of the other caster means, and the wheel of the other caster means is rotated on the floor.

According to the present invention, the caster movably supporting means can further support the other caster means at the corresponding other one of the positions near the front and rear ends of the lower end portion of the support structure member to move the other caster means between a projecting position, at which the other caster means projects downward from the corresponding other one of the positions near the front and rear ends of the lower end portion of the support structure member, and the retracted position, at which the other caster means is retracted and stored in the corresponding other one of the positions near the front and rear ends of the lower end portion of the support structure member. And the interconnecting means can also move the other caster means from the projecting position to the retracted position in response to the pivotal movement of the top plate from the folded Dos-'L."-,Lcn to the.horizontal position, and move the other caster 8 - means from the retracted position to the projecting position in response to the pivotal movement of the top plate from the horizontal position to the folded position.

This invention can be more fully understood from the following detailed description when taken in conjunction with the accompanying drawings, in which:

Fig. 1 is a schematic front view of a movable table according to a first embodiment of the present invention while its top plate is set at a horizontal position; Fig. 2A is a schematic side view of the movable table shown in Fig. 1 in a state in which antiskid members stably support rear end portions of a pair of legs of the table on a floor in place of retracted casters at the rear end portions of the paired legs while the top plate is set at the horizontal position; Fig. 2B is a schematic side view of the movable table shown in Fig. 1 in a state in which the paired casters set at lower projecting positions at the rear end portions of the paired legs support the rear end portions on the floor in place of the antiskid members, so that the moval table is easily movable on the floor while the top plate is set at a folded position, and a plurality of movable tables with their top plates be4Lng folded are arranged adjacent to each other on the for the purpose of storage; Fig. 3 is a side view showing a structure of 9 - movable table of the first embodiment in detail while its top plate is set at the horizontal position; Fig. 4 is a schematic perspective view of a caster support structure for the casters located at the front and rear end portions of one of the legs of the movable table of the first embodiment; Fig. 5 is a schematic perspective view showing support structures for the top plate and a modesty panel of the movable table of the first embodiment; Fig. 6 is a schematic front view showing support structures for the top plate, the modesty panel, and luggage racks of the movable table of the first embodiment; Fig. 7 is a side view showing the structure of the movable table of the first embodiment in detail when its top plate is set at the folded position; Fig. 8 is a schematic side view showing support structures for casters at front and rear end portions of one of a pair of legs of a movable table according to a second embodiment of the present invention, in a state that an antiskid member is set at a lower projecting position in place of the caster located at a retracted position in the rear end portion; Fig. 9 is a schematic perspective view showing support structures for the casters at the front and rear end portions of the above described one leg of the second embodiment; A - is Fig. 10 is a schematic side view showing the support structures for the casters at the front and rear end portions of the above described one leg of the movable table according to the second embodiment of the present invention, in a state that the caster at the rear end portion is set at a lower projecting position in place of the retracted antiskid member at the rear end portion; Fig. 11 is a side view showing a structure of a movable table according to a third embodiment of the present invention in detail when its top plate is set at a horizontal position; Fig. 12 is a schematic perspective view showing support structures for casters at front and rear end portions of one of a pair of leg of the third embodiment; and Fig. 13 is a side view showing the structure of the movable table of the third embodiment in detail when its top plate is set at the folded position.

[outline of First Embodiment and Detailed Description of Its Construction]

Figs. 1 and 2A show front and side views of a movable table 10 according to a first embodiment of the present invention.

The movable table 10 has a pair of legs 14 extending downward from both longitudinal end portions off a lower surface of a rectangular top plate 12. The pair of legs 14 have vertically extending columns 14a extending substantially vertically, and are coupled to each other to be in parallel with each other by a horizontal coupling member 14b horizontally extending between vertically intermediate positions of the vertically extending columns 14a, thereby constituting the support is structure member for the top plate 12.

A pair of top plate brackets 12a are fixed to the both longitudinal end portions of the lower surface of the top plate 12 to extend in a front-to-rear direction of the top plate 12 at positions located in inner sides of and adjacent to upper end portions of the vertically extending columns 14a of the paired legs 14. The paired top plate brackets 12a are coupled to the upper end portions of the vertically extending columns 14a of the paired legs 14 so as to make the top plate 12 being pivotable between a substantially horizontal position shown in Figs. 1 and 2A and a substantially vertical folded position shown in Fig. 2B.

Front-to-rear extending members 14C that extend in the front-to-rear direction are fixed to lower end por tions of the paired vertically extending columns 14a.

Downwardly projecting casters 16a and 16b are supported at front and rear end portions of each front-to-rear extending member 14c. A downwardly projecting antiskid member 18 is supported at the rear end por-.--'on of each front-to-rear extending member 14c.

12 - In this embodiment, the caster 16b at the rear end portion is vertically movable between a downward projecting position and a retracted position in response to the pivotal movement of the top plate 12 between the horizontal and folded positions by an interconnecting means (to be described later in detail) housed in each leg 14. The caster 16b at the downward projecting position projects downward from the rear end portion of the corresponding front-to-rea.r extending member 14c, and at the retracted position is retracted and stored in the corresponding rear end portion.

More specifically, the casters 16a at the rear end portions are set at the retracted positions when the top plate 12 is set at the horizontal position as shown in is Figs. 1 and 2A, and accordingly the casters 16b are located above the antiskid members 18. That is, when the top plate 12 is set at the horizontal position as shown in Figs. 1 and 2A, the movable table 10 of the first embodiment is supported on a floor 20 by the casters 16a and the antiskid members 18 at the front and rear end portions of the front-to-rear extending members 14c of the paired legs 14.

The casters 16b at the rear end portions are set at the downward projecting positions when the top plate 12 is set at the folded position as shown in Fig. 2B, and accordingly the casters 16b project downward below the antiskid members 18. That is, when the top plate 12 is 13 - set at the folded position as shown in Fig. 2B, the movable table 10 of the first embodiment is supported on the floor 20 by the casters 16a and 16b at the front and end portions of the front-to-rear extending members 14c of the paired legs 14.

In this embodiment, a laterally elongated modesty panel 22 is disposed in front of the vertically extending columns 14a of the paired legs 14 to horizontally extend between the legs 14. The modesty panel 22 is coupled to the paired vertically extending columns 14a and the top plate 12 so as to move between a forward moving position (Fig. 2A) and a retracted position (Fig. 2B) in a state that it is in parallel to the paired vertically extending columns 14a. The parallel movement of the modesty panel 22 is caused by the Divotal movement of the top plate 12 between the horizontal and folded positions. The modesty panel 22 at the forward moving position projects forward from the paired vertically extending columns 14a, and at the retracted position 22 is retracted to close to front surfaces of the paired vertically extending columns 14a.

Furthermore, in this embodiment, three luggage racks 24 are disposed under the top plate 12 between the paired legs 14 and are coupled to the lower surface of the top plate 12. These luggage racks 24 are movable between downward moving positions (Fig. 2A) and retracted positions (Fig. 2B) in a state that they are - 14 in parallel to the lower surface. The parallel movement of the luggage racks 24 are also caused by the pivotal movement of the top plate 12. The luggage racks 24 at their downward moving positions are separated from the lower surface of the top plate 12 by a predetermined distance, and at their retracted positions close to the lower surface of the top plate 12.

Since the casters 16b at the rear ends are set at the retracted positions and accordingly located above the antiskid members 18 when the top plate 12 is set at the horizontal position as shown in Figs. 1 and 2A (i.e., when the movable table 10 of the first embodiment is used), an unexpected movement of the movable table 10 by an accidental external force applied thereto while it is is used is reliably prevented.

While the movable table 10 is used, however, if a rear end portion of the top plate 12 is lifted and the movable table 10 is supported on the floor 20 by only the paired casters 16a at the front end portions, the movable table 10 can be moved on the floor 20 by a comparatively small force in a state that the wheels of the paired casters 16a are rotated on the floor 20.

While the movable table 10 is not in use, if the top plate 12 is set at the folded position as shown in Fig. 2B, the casters 16b at the rear end portions can be easily projected downward below the antiskid members 18 by utilizing the weight-of the top plate 12, against the is - is weight of the movable table 10. More specifically, even a physically weak person, e.g., a female, a child, and an aged person, can easily change the movable table 10 against its weight from a stably stopped use state as shown in Fig. 2A to a movable state as shown in Fig. 2B. The movable table 10 in the movable state is supported on the floor 20 by the two paired front and rear casters 16a and 16b. Therefore, the movable table 10 in the movable state can be easily moved to a desired position on the floor 20 with a small force.

Furthermore, the modesty panel 22 and the luggage racks 24, set at the retracted positions as shown in Fig. 2B by setting the top plate 12 at the folded position, minimize a distance between a front surface of the modesty panel 22 at the retracted position and an outer flat surface of the top plate 12 at the folded position. More specifically, when a large number of movable tables 10 are gathered close to each other in the frontto-rear direction in a state that the front- torear extending members 14c of the legs 14 of one movable table 10 and the other movable table 10 behind the above described one are located side by side until the outer flat surface of the folded top plate 12 of one movable table 10 contacts the front surface of the modesty panel 22 of the movable table 10 behind the above described one, an area on the floor 20 requLred for storing the large number of movable tables 10 can be - 16 minimized.

With reference to Figs. 3 to 6, the caster support structures for the two pairs of front and rear casters 16a and 16b, the caster movably supporting means for the vertical movement of the casters 16b at the rear end portions, the caster interconnecting means for verti cally moving the casters 16b at the rear end portions in response to the pivotal movement of the top plate 12 between the horizontal and folded positions, the modesty panel interconnecting means for moving the modesty panel 22 in the front-to-rear direction in a parallel state in response to the pivotal movement of the top plate 12 between the horizontal and folded positions, and the luggage rack interconnecting means for moving the luggage racks 24 in a parallel state in response to the pivotal movement of the top plate 12 between the hori zontal and folded positions will be described in detail.

Functions of the above described structures and means have been schematically described with reference to Figs. 1 to 2B.

Each of the front-to-rear extending members 14c of the paired legs 14 is made of, e.g., a steel to have a substantially inverted U-shaped crosssection, and its front and rear ends are closed. As shown in Fig. 3, a connecting opening 30 for connecting with the lower end of the vertically extending column -14-a -4s fon-red in the front end portion of each frontto-rear extending - 17 is member 14c.

The antiskid member 18 arranged to rear end portion of lower surface of each front-to-rear extending member 14c is fixed to a lower end portion of a screw threadably engaged with the rear end portion of the lower surface of the front-to-rear extending member 14c. Thus, a downward projecting height of the antiskid member 18 from the lower surface of the rear end portion can be adjusted.

A front-to-rear extending beam 32 is disposed in an inner space of each frontto-rear extending member 14c to extend from its front end to the vicinity of the antiskid member 18 at its rear end portion. The fronttorear extending beam 32 is formed by a press work from a steel plate to have a substantially U-shaped angular cross section as shown in Fig. 4. An upper end portion of a vertical rotational center shaft 34 of the front caster 16a is fixed to a front end portion of a flat lower surface of the front-to-rear extending beam 32, and an upper end portion of a vertical rotational ceniter shaft 38 of the rear caster 16b is fixed to a rear end portion of the flat lower surface of the frontto-rear extending beam 32 through a vertical guide member 36.

A lever member 40 is housed in an upper opening of the front-to-rear extending beam 32 to extend in the front-to-rear direction between the upper end portions of the vertical rotational center shaft-s 34 and 38 of 18 the paired front and rear casters 16a and 16b. The lever member 40 is formed by a press work from a steel plate to have a substantially inverted U-shaped angular cross section, as shown in Fig. 4. Rear end portions of both side walls of the lever member 40 are rotatably attached by a rotational center shaft 42 to both side walls of the front-to-rear extending beam 32.

Front end portions of the both side walls of the front-to-rear extending beam 32 are rotatably attached by a rotational center shaft 44 to front end portions of both side walls of the front-to-rear extending member 14c of the corresponding leg 14. when the front-to-rear extending beam 32 vertically pivots around the rotational center shaft 44 at its front end portion, the caster 16b at its rear end portion is vertically moved between the retracted position (Figs. 2A and 3) at which the caster 16b retracts above the antiskid member 18 into the front-to-rear extending beam 32, and the downward projecting position (Fig. 2B) at which the caster 16b projects downward below the antiskid member 18.

The vertical guide member 36 at the rear end portion of the front-to-rear extending beam 32 contacts the inner surfaces of both of the side walls of the frontto-rear extending member 14c and slides on them when the front-to-rear extending beam 32 vertically pivots. Thus, the rear end portion of the front-to-rear extending beam 32 can vertically moves without side shifting.

is If the vertical guide member 36 is formed of, e.g., a synthetic resin having both wearing-resistant property and low frictional property, the front-torear extending beam 32 can smoothly vertically pivot without producing noise.

A fulcrum projection 46 is formed on an upper surface of the inner space of the front-to-rear extending member 14c of the leg 14, and contacts an upper surface of the lever member 40 at a position immediately in front of the rotational center shaft 42 of the rear end portion, as shown in Fig. 3.

Each of the vertically extending columns 14a of 'L-.he paired legs 14 is formed by a hollow aluminum-alloy pipe having a substantially square cross section, and its lower end portion is connected and fixed to the connecting opening 30 in a front end portion of an upper surface of the corresponding front-to-rear extending member 14c.

End caps 48 formed separately from the vertically extending columns 14a are fixed to upper end openings of the corresponding vertically extending columns 14a, as shown in Figs. 3 and 5. Upper end surfaces of the end caps 48 are flattended and stably support the top plate 12 in the horizontal position when they abut against the lower surface of the top plate 12 set in the horizontal position, as shown in Figs. 2A a-'d 3.

An opening is formed in an inner side surface of is the end cap 48, and fixing screw holes 50a and 50b are formed at an upper- rear end portion and at a lower-front end portion, respectively, in a periphery of the opening, as shown in Fig. 5.

Each of the paired top plate brackets 12a at the both longitudinal end portions of the lower surface of the top plate 12 has a substantially Ushaped cross section. Upper ends of both side walls of each top plate bracket 12a are bent to the right and left, respectively, in the horizontal direction to form horizontal flanges to be overlapped with the lower surface of the top plate 12. The horizontal flanges are fixed to the lower surface of the top plate 12 by a known fixing means, e.g., a screw.

A reinforcing plate 52 having a substantially Ushaped cross section covers a region of an outer surface of each of the paired top plate brackets 12, the region extending from a longitudinal central portion of the outer surface by a small distance. A bolt 54 serving as a rotational center shaft for the top plate 12 horizontally passes through rear end portions of both side walls of the reinforcing plate 52 and the both side walls of the corresponding top plate bracket 12 from the inner side thereof to the outer side thereof, and is threadably engaged in the corresponding fixing screw hole 50a at the upper-rear end portion of the end cap 48 on the upper end of the.vertically extending column 14a 21 - of the corresponding leg 14.

An engaging pin 56 projects from an outer side surface of the reinforcing plate 52 at a position in front of the rotational center bolt 54 and is inserted into the opening in the inner side surface of the end cap 48 at the upper end of the vertically extending column 14a of the corresponding leg 14.

A thin, elongated vertically movable member 58 extends in an inner space of each of the vertically extending columns 14a of the paired legs 14 froman inner space of the end cap 48 at the upper end of the corresponding vertically extending column 14a to a front end portion of the inner space of the corresponding front-to-rear extending member 14c at the lower end.

The vertically movable member 58 has a tension coil spring 58a at its intermediate portion. In this embodiment, the vertically movable member 58, together with the tension coil spring 58a, is formed of one steel wire. In the inner spaces of the end caps 48 at the upper ends of the vertically extending columns 14a of the paired legs 14, upper end portions of the vertically movable members 58 engage with the corresponding engaging pins 56 of the reinforcing plates 52 of the paired top plate brackets 12a, and lower end portions of the vertically movable members 58 engage with front end portions of the corresponding lever members 40 in the front end portions of the inner spaces of the 22 - front-to-rear extending members 14c at the lower ends of the vertically extending columns 14a of the paired legs 14, as shown in Figs. 3 and 4.

A rotational center shaft 60a of a lock lever 60 for selectively holding the top plate 12 at the horizontal position is inserted through the both side surfaces of the reinforcing plate 52 of each of the paired top plate brackets 12a and the both side surfaces of the corresponding top plate bracket 12a at a position in front of the engaging pin 56. A horizontally outwardly spreading finger hook 60b projects forward from an outer end of each lock lever 60 to a position near a rear surface of the modesty panel 22, and an engaging piece 60c spreading in the fronttorear direction projects downward from the outer end of each lock lever 60.

An engaging recess 60d is formed in an outer side surface of the engaging piece 60c to extend substantially horizontally from a rear edge thereof toward a front edge thereof, and a head portion of a lock bolt 64, the lock bolt 64 being inserted through a spacer 62 and screwed into the fixing screw hole 50b at the lower-front end portion of the end cap 48 at the upper end of the corresponding vertically extending column 14a, together with the spacer 62, is engaged in the engaging recess 60d.

An inner end portion of.the rotational center shaft 60a projects inwardly from an inner side surface of the - 23 reinforcing plate 52 of each of the paired top plate brackets 12a, and a torsion coil spring 66 is wound around the inner end portion of the rotational center shaft 60a. one end of the torsion coil spring 66 is engages with the inner side surface of the corresponding reinforcing plate 52, and its other end engages with an engaging pin 68 fixed to an outer surface of the inner end portion of the rotational center shaft 60a of the lock lever 60. The torsion coil spring 66 urges the lock lever 60 to move backward its engaging piece 60c.

Thus, the lock lever 60 is urged by the urging force of the torsion coil spring 66 to maintain the engagement of the engaging recess 60d of the engaging piece 60c with the lock bolt 64.

The inner end portions of the rotational center shafts 60a of the paired lock levers 60 are coupled to each other by a horizontally extending common shaft 70, so that any one of the paired lock levers 60 can be operated by the other.

While the top plate 12 is set in the horizontal position, as shown in Fig. 3, the engaging recesses 60d of the engaging pieces 60c of the lock levers 60 of the top plate brackets 12a engage with the lock bolts 64 at the end caps 48 at the upper ends of the vertically extending columns 14a of the paired legs 14. These engagement reliably prevent the pivotal movement of the top plate 12 from the horizontal position against a pivoting force applied to the top plate 12.

These engagement can be released by pivoting either lock lever 60 against the urging force of the corre sponding torsion coil spring 66 to move forward the engaging piece 60c.

Side covers 22a are attached to right and left ends of the modesty panel 22 and extend in the front-to-rear direction to close to outer side surfaces of the verti cally extending columns 14a of the paired legs 14. A pair of modesty panel link connecting angle members 72a and 72b are located at vertically separate positions on each of right and left end portions of a back surface of the modesty panel 22. one end of each of the angle mem bers 72a and 72b is fixed to the corresponding position is on the back surface of the modesty panel 22.

The other end of each of the modesty panel link connecting angle members 72a and 72b projects backward, and is connected to a corresponding one end portion of each of a pair of upper and lower link members 74a and 74b to allow the corresponding one of the link members 74a and 74b to be vertically pivotal. The other end portion of the upper link member 74a is vertically pivotally coupled to a tongue piece 76 extending down ward from a position of a lower surface of the reinforc ing plate 52 of the corresponding top plate bracket 12a, the position being located in front of the rotational center bolt 54. The other end portion of the lower link - is member 74b is vertically pivotally coupled to an inner side surface of the vertically extending column 14a of the corresponding leg 14.

The paired upper and lower link members 74a and 74b constitute a parallel link mechanism for approaching and separating the modesty panel 22 to and from front surfaces of the vertically extending columns 14a of the paired legs 14 in a substantially parallel manner in response to with the pivotal movement of the top plate 12 between the horizontal position shown in Figs. 2A and 3 and the folded position shown in Fig. 2B.

While the top plate 12 is set at the horizontal position shown in Figs. 2A and 3, upper edges of the lower link members 74b abut against stoppers 78 of the corresponding modesty panel link connecting angle members 72b, as shown in Figs. 3 and 5, to restrict the downward movement of the lower link member 74b. Hence, the paired link members 74a and 74b are held to extend horizontally in the front-to-rear direction. As a result, the modesty panel 22 is held at the forward projecting position away from the front surfaces of the vertically extending columns 14a of the paired legs 14 in the forward direction against its own weight.

Three pairs of rack shelf brackets 80 are fixed to the lower surface of the top plate 12 between the pair of top plate brackets 12a to extend in the frc.------to-rear - 26 direction and to be parallel to the paired top plate brackets 12a, as shown in Figs. 3 and 6. Upper end portions of a pair of downward extending parallel link mem- bers 82a and 82b are coupled to front and rear end portions of each rack shelf bracket 80 to be vertically pivotal. The pair of parallel link members 82a and 82b are stopped at inclined positions by stoppers 84 formed on the corresponding rack shelf bracket 80 so that their lower end portions are located behind the upper end portions.

Front and rear end portions of one of right-and left end surfaces of the luggage rack 24 are vertically pivotably coupled to the lower end portions of the paired corresponding parallel link members 82a and 82b.

Hence, in response to the pivotal movement of the top plate 12 between the horizontal and folded positions, each luggage rack 24 can be moved between a lower moving position and a retracted position. The luggage rack 24 at the lower moving position is located below and parallel to the horizontal top plate 12 to be spaced apart from it by a predetermined distance, as shown in Figs. 2A and 3, and at the retracted position is located adjacent to the lower surface of the folded top plate 12 to be substantially parallel to it, as shown in Fig. 2B.

[Operation of the First Embodiment] The operation of the movable table 10 acco.-d-.ng to - 27 the first embodiment of the present invention will be described below.

When the lock levers 60 on the front end portions of the outer side surfaces of the paired top plate brackets 12a pivot against the urging forces of the torsion coil springs 66 (see Figs. 5 and 6), the engaging recesses 60d of the engaging pieces 60c of the lock levers 60 are disengaged from the lock bolts 64 at the lower-front end portions of the inner side surfaces of the end caps 48 at the upper ends of the vertically extending columns 14a of the paired legs 14, and hence the pivotal movement of the top plate 12 from the horizontal position is enabled.

when the top plate 12 pivots around the rotational is center bolts 54 at the upper-rear end portions of the inner side surfaces of the end caps 48 at the upper ends of the vertically extending columns 14a of the paired legs 14 to move downward the rear end of the top plate 12, the engaging pins 56 of the reinforcing plates 52 of the paired top plate brackets 12a of the to-P plate 12 are moved upward. Hence, the vertically movable members 58 are moved upward in the inner spaces of the verti cally extending columns 14a of the paired legs 14 to lift the front end portions of the lever members 40 in the front end portions of the inner spaces of the frontto-rear extending members 14P of the paired, legs 14. At this time, the lever members 40 pivot around the fulcrum - 28 is projections 46 at the upper portions of the inner surfaces of the fronttorear extending members 14c to move downward the rear end portions of the lever members 40.

The rear end portions of the lever members 40 push downward the rear end portions of the corresponding front-to-rear extending beams 32 to pivot them around the front rotational center shafts 44 so that the rear end portions of the front-to-rear extending beams 32 are moved downward. when the top plate 12 reaches the folded position at which the top plate 12 is substantially vertical and is adjacent to the rear surfaces of the vertically extending columns 14a of the paired legs 14, as shown in Fig. 2B, the casters 16b at the rear end portions of the front-to-rear extending beams 32 project downward until the distances from the lower surfaces of the rear end portions of the front-torear extending members 14c to the casters 16b become larger than the distances from the same to the antiskid members 18.

As a result, in the movable table 10, the rear end portions of the frontto-rear extending members 14c are moved upward around the wheels of the front paired casters 16a, and the rear end portions of the front-torear extending members 14c are supported on Che floor 20 by the rear paired casters 16a projecting downward below the antiskid members 18.

29 - is The upward movement described above against the weight of the movable table 10 is performed by utilizing a force which is obtained by multiplying a rotating force, generated by the weight of the top plate 12 when the top plate 12 pivots from the horizontal position to the folded position, by the lever members 40 in the front-to-rear extending members 14c. Thus, a large force is not required for this upward movement (i.e., shift of the movable table 10 from the still state to the movable state).

The movable table 10 in which the front and rear end portions of the front-to-rear extending members 14c of the paired legs 14 are supported on the floor 20 by the two pairs of casters 16a and 16b can be easily moved to a desired position on the floor 20 with a small force.

Fig. 7 shows the various construction elements of the movable table 10 whose top plate 12 is set at the folded position in detail.

when the top plate 12 pivots from the horizontal position shown in Fig. 3 to the folded position shown in Fig. 7, the tongue pieces 76 of the paired top plate brackets 12a are moved upward. Thus, the rear end portions of the paired upper link members 74a for the modesty panel 22, which are coupled to the tongue pieces 76, are lifted upward from the hor- izo,-11al positions shown in Fig. 3. These lifted rear end portions of the paired upper link members 74a lift, together with the modesty panel 22, the front end portions of the paired lower link members 74b for the modesty panel 22.

owing to the function of the parallel link mecha nism constituted by the paired upper link members 74a and the paired lower link members 74b, the modesty panel 22 is moved upward from the forward moving position shown in Fig. 3 to the retracted position shown in Fig. 7 defined in the vicinity of the vertically extend ing columns 14a of the paired legs 14 in the parallel manner to the front surfaces of the vertically extending columns 14a.

When the top plate 12 pivots from the horizontal position shown in Fig. 3 to the folded position shown in Fig. 7, the three luggage racks 24 on the lower surface of the top plate 12 are moved downward by their own weight such that their rear end portions are directed downward. During the pivotal movement of the luggage racks 24, the two pairs of parallel link members 82a and 82b for the respective luggage racks 24 are moved from the downward moving positions shown in Fig. 3 to the retracted positions defined in the vicinity of t-he lower surface of the top plate 12 in the parallel manner to the lower surface of the top plate 12.

The respective luggage racks 24 set at the retracted positions are housed within the height of the paired top plate brackets 12a, as shown in Fig. 7, and i- 31 - do not interfere with the movement of the top plate 12 and the modesty panel 22 toward the front and rear surfaces of the vertically extending columns 14a of the paired legs 14. [Second Embodiment] The second embodiment of the present invention will be described with reference to Figs. 8 to 10.

In the second embodiment, the casters 16b at the rear end portions of the frontto-rear extending members 14c of the paired legs 14 pivots vertically in response to the pivotal movement of the top plate 12 between the horizontal position and the folded position, so that they pivot between the downward projecting positions and the retracted positions. The rear casters 16b at the downward projecting positions project downward from the rear end portions of the front-to-rear extending members 14c, and at the retracted positions retract in the rear end portions. Antiskid members 110 are integrally formed with caster support members 102 for the rear casters 16b and pivot together with the casters 16b. when the casters 16b are set at the downward projecting positions, the antiskid members 110 are set at retracted positions at which the antiskid members 110 are retracted in the rear end portions. When the rear casters 16b are set at the retracted positions, the antiskid members 110 are set at the downward projecting pos-J-'---ions to project downward from the rear end portions o'E' the 32 front-to-rear extending members 14c.

The second embodiment is substantially the same as the first embodiment, except for interconnecting means for pivoting the rear casters 16b in response to the pivotal movement of the top plate 12 and a support structure for the antiskid members 110 and the casters 16b. Thus, only the members of the second embodiment that are different from those of the first embodiment will be described.

In this embodiment, the vertical rotational canter shafts of the front casters 16a are supported by front caster brackets 90 fixed in the inner spaces of the front end portions of the front-to-rear extending members 14c, as shown in Fig. 8.

The vertically extending members 58 vertically extending in the inner spaces of vertically extending columns 14a of the paired legs 14 are constituted by rods or the like. The upper ends of the vertically extending members 58 are vertically pivotably coupled to the engaging pins 56 of the corresponding top plate brackets 12a in the same manner as in the first embodiment described above.

Substantially triangular link members 92 are disposed behind the front casters 16a in the front end portions of the inner spaces of the front-to-rear extending members 14c of the paired legs 14, as shown in Figs. 8 and 9. Rotational center shafts 94 fixed at 33 upper vertices of the triangular link members 92 are supported by bearings 96 fixed in the inner spaces of the front-to-rear extending members 14c, so that the link members 92 can pivot vertically around the shafts 94.

The lower end portions of the vertically extending members 58 are coupled to rotational center shafts 97 fixed to front vertices of the triangular link members 92 so as to be vertically pivotal around the rotational center shafts 97.

Front end portions of front-to-rear extending beams extending in the inner spaces of the front-to-rear extending members 14c toward their rear end portions are coupled to rotational center shafts 98 fixed to rear is vertices of the triangular link members 92 so as to be vertically pivotal around the rotational center shafts 98.

The caster support members 102 supporting the vertical rotational center shafts of the rear centers 16b are disposed in the rear end portions of the inner spaces of the front-to-rear extending members 14c. The caster support members 102 are supported at their rotational.center shafts 104 by bearings 106 fixed to the inner spaces of the front-to-rear extending members 14c so as to be vertically pivotal around the shafts 104.

when the caster support members 102 vertically pivot around the rotational center shafts 104, the rear - 34 casters 16b on the caster support members 102 pivot between the retracted positions, as shown in Figs. 8 and 9, and the downward projecting positions, as shown in Fig. 10.

The front-torear extending beams 100 extending backward from the corresponding link members 92 are coupled at their rear end portions to rotational center shafts 108 fixed to upper end portions of the caster support members 102 so that the beams 100 are vertically pivotal around the rotational center shafts 108.

The antiskid members 110 are integrally formed with rear end portions of the caster support members 102. When the rear casters 16b pivot between the retracted positions and the downward projecting positions by the vertical pivotal movement of the caster support members 102, the antiskid members 110 pivot between the downward projecting positions and the retracted positions in the opposite manner to the casICers 16b. More specifically, when the rear casters 16b are set at the retracted positions, the antiskid members 110 are set at the downward projecting positions below the retracted rear casters 16b, as shown in Figs. 8 and 9. when the rear casters 16b are set at the downward projecting positions, the antiskid members 110 are set at the retracted positions above the downward projecting rear casters 16b, as shown in Fig, 10.

When the antiskid members 110 are se-IC aL- the is downward projecting positions, they stably support the corresponding rear end portions of the front-to-rear extending members 14c of the paired legs 14 on the floor 20, in place of the retracted rear casters 16b. when the antiskid members 110 are set at the retracted positions, they enable the corresponding rear end por tions of the frontto-rear extending members 14c of the paired legs 14 to be freely movably supported on the floor 20 by the downward projecting rear casters 16b.

In the second embodiment constructed as described above, while the top plate 12 is set at the horizontal position, the vertically extending members 58 in the inner spaces of the vertically extending columns 14a of the paired legs 14 are pushed downward. Hence, the front-to-rear extending beams 100 in the inner spaces of the front-to-rear extending members 14c of the paired legs 14 are pushed backward by the action of the link members 92. Eventually, the antiskid members 110 at the rear end portions of the front-torear extending members 14c are set at the downward projecting positions, and the rear casters 16b are set at the retracted positions, as shown in Fig. 8.

When the top plate 12 pivots from the horizontal position to the folded position, the vertically extending members 58 in the inner spaces of the vertically extending columns 14a of the paired le-s 14 are l-Lf--ed. Hence, the front-to-rear extending bears 100 in the i is inner spaces of the front-to-rear extending members 14c of the paired legs 14 are pulled forward by the action of the link members 92. Eventually, the antiskid mem bers 110 at the rear end portions of the front-to-rear extending members 14c are lifted to the retracted positions, and the rear casters 16b are moved downward to the downward projecting positions, as shown in Fig. 10.

[Third Embodiment] The third embodiment of the present invention will be described with reference to Figs. 11 to 13.

In the third embodiment, the casters 16a and 16b at the front and rear end portions of each of the front-to rear extending members 14c of the paired legs 14 pivot in the vertical direction in response to the pivotal movement of the top plate 12 between the horizontal position and the folded position. Hence, the casters 16a and 16b simultaneously pivot between the downward projecting positions at which both of the casters 16a and 16b project downward from the front and rear end portions of the front-to-rear extending members 14c, and the retracted positions at which both of the casters 16a and 16b retract into the front and rear end portions of the front-to-rear extending members 14c. Antiskid mem bers 120a and 120b are integrally formed with caster.

support members 122a and 122b for the front and rear casters 16a and 16b, and pivot together with the 1 - 3 corresponding casters 16a and 16b. when both of the casters 16a and 16b are set at the downward projecting positions, both of the antiskid members 120a and 120b are set at retracted positions to be retracted into the front and rear end portions of the front-to-rear extend ing members 14c. When the casters 16a and 16b are set at the retracted positions, the antiskid members 120a and 120b are set at downward projecting positions to project downward from the front and rear portions of the front-to-rear extending members 14c.

The third embodiment is substantially the same as that of the first embodiment, except for an intercon necting means for pivoting the front and rear casters 16a and 16b in response to the pivotal movement of the top plate 12, and a support structure for the front and rear antiskid members 120 and 120b and the front and rear casters 16a and 16b. Thus, only the members of the third embodiment that are different from those of the first embodiment will be described.

In this embodiment, the vertically extending mem bers 58 vertically extending in the inner spaces of the vertically extending columns 14a of the paired legs 14 are constituted by rods or the like. Upper ends of the vertically extending members 58 are coupled to the engaging pins 56 of the corresponding top plate brackets 12a to be vertically movable in the samne manner as in the.first embodiment described above.

38 - Substantially triangular link members 124 are disposed behind the front casters 16a in the front end portions of the inner spaces of the fronttorear extending members 14c of the paired legs 14, as shown in Figs. 11 and 12. The link members 124 are vertically pivotably supported at their rotational center shafts 126, fixed to their central portions, by bearings 128 (Fig. 11) fixed in the inner spaces of the front-to-rear extending members 14c.

The lower end portions of the vertically extending members 58 are coupled to rotational center shafts 130 fixed to front summits of the triangular link members 124 to be vertically pivotal around the rotational center shafts 130.

Rear end portions of first front-to-rear extending beams 134a extending in the inner spaces of the frontto-rear extending members 14c toward the corresponding front casters 16a are coupled to rotational center shafts 132 (Fig. 12) fixed to upper summits of the triangular link members 124 to be vertically pivotal around the rotational center shafts 132.

The caster support members 122a supporting the vertical rotational center shafts of the front casters 16a are disposed at the front end portions of the inner spaces of the front-to-rear extending members 14c. The caster support members 122a are supported a-IC. -t'--heir rotational center shafts 136a by bearings 138a fixed to the 1 1 39 - inner spaces of the front-to-rear extending members 14c.

When the front caster support members 122a verti cally pivot around the rotational center shafts 136a, the front casters 16a on the caster support members 122a pivot between retracted positions and downward project ing positions. The front casters 16a at the retracted positions retract into the rear end portions, as shown in Fig. 11, and at the downward projecting positions project downward from the rear end portions, as shown in Fig. 13.

Front end portions of the first front-to-rear extending beams 134a extending forward from the corre sponding link members 124 are coupled to rotational center shafts 140a (Figs. 11 and 12) fixed to upper end is portions of the front caster support members 122a to be vertically pivotal around the rotational center shafts 140a.

The antiskid members 120a are integrally formed with front end portions of the caster support members 122a. when the front casters 16a pivot between the retracted positions and the downward projecting posi tions by the vertical pivotal movement of the caster support members 122a, the antiskid members 120a pivot between the downward projecting positions and the retracting positions in the opposite manner to the cas ters 16a. More specifically, when the front casters 16a are set at the retracted positions, the front antiskid members 120a are set at the downward projecting posi tions below the retracted front casters 16a, as shown in Fig. 11. When the front casters 16a are set at the downward projecting positions, the front antiskid mem bers 120a are set at the retracted positions above the downward projecting front casters 16a, as shown in Figs. 12 and 13.

When the front antiskid members 120a are set at the downward projecting positions, they stably support the corresponding front end portions of the front-to-rear extending members 14c of the paired legs 14, in place of the retracted front casters 16a. when the front ant iskid members 120a are set at the retracted positions, they enable the corresponding front end portions of is the frontto-rear extending members 14c of the paired legs 14 to be freely movably supported on the floor 20 by the downward projecting front casters 16a.

Front end portions of second front-to-rear extend ing beams 134b extending in the inner spaces of the front-to-rear extending members 14c toward the corre sponding rear end portions are coupled to rotational center shafts 142 (Figs. 11 and 12) fixed to lower sum mits of the substantially triangular link members 124 to be vertically pivotal around the rotational center shafts 142.

The caster support members 122b supporting the ver tical rotational center shafts of the rear casters 16b are disposed at the rear end portions of the inner spaces of the front-to-rear extending members 14C.

caster support members 122b are vertically pivotably supported at their rotational center shafts 136b fixed to them by bearings 138b fixed to the inner spaces of the front-torear extending members 14c.

When the caster support members 122b vertically pivot around the rotational center shafts 136b, the rear casters 16b on the caster support members 122b pivot between the retracted positions to retract the casters 16b into the rear end portions, as shown in Fig. 11, and the downward projecting positions to project the casters 16b downward from the rear end portions, as shown in Fig. 12.

Rear end portions of the front-to-rear extending beams 134b extending backward from the corresponding link members 124 are coupled to rotational center shafts 140b (Figs. 11 and 12) fixed to upper end portions of the rear caster support members 122b to be vertically pivotal around the rotational center shafts 140b.

The antiskid members 120b are integrally formed with rear end portions of the rear casters support mem bers 122b. when the rear casters 16b pivotbetween the retracted positions and the downward projecting posi tions by the vertical pivotal movement of the rear cas ter support members 122b, the rear antiskid members 120b pivot between the downward projecting positions and the retracted positions in the opposite manner to the casters 16b. More specifically, when the rear casters 16b are set at the retracted positions, the rear antiskid members 120b are set at the downward projecting positions below the retracted casters 16b, as shown in Fig. 11. When the rear casters 16b are set at the downward projecting positions, the rear antiskid members 120b are set at the retracted positions above the downward projecting rear casters 16b, as shown in Figs. 12 and 13.

When the rear antiskid members 120b are set at the downward projecting positions, they stably support the corresponding rear end portions of the frontto-rear extending members 14c of the paired legs 14, in place of the retracted rear casters 16b. when the antiskid members 120b are set at the retracted positions, they enable the corresponding rear end portions of the frontto-rear extending members 14c of the paired legs 14 to be freely movably supported on the floor 20 by the downward projecting rear casters 16b.

In the third embodiment constructed as described above, while the top plate 12 is set at the horizontal position, the vertically extending members 58 in the inner spaces of the vertically extending columns 14a of the paired legs 14 are pushed downward. Hence, the first and second front-to-rear extending beams 134a and 134b in the inner spaces of the front-to-rear extending 43 member 14c at the lower ends of the paired legs 14 are pushed forward and backward, respectively, by the action of the link members 124. Eventually, the antiskid members 120a and 120b at the front and rear end portions of the front-to-rear extending members 14c are simultaneously set at the downward projecting positions, and the front and rear casters 16a and 16b are simultaneously set at the retracted positions, as shown in Fig. 10.

When the top plate 12 pivots from the horizontal position to the folded position, the vertically extending members 58 in the inner spaces of the vertically extending columns 14a of the paired legs 14 are lifted. Hence, the first and second front-to-rear extending beams 134a and 134b in the inner spaces of the front-torear extending members 14c at the lower ends of the paired legs 14 are pulled forward and backward, respectively, by the action of the link members 124. Eventually, the front and rear antiskid members 120a and 120b at the front and rear end portions of the front-torear extending members 14c are lifted to the retracted positions, and the front and rear casters 16a and 16b are moved downward to the downward projecting positions, as shown in Fig. 12.

Claims

Claims:

A caster support structure, which is provided to a movable table comprising a support structure member extending substantially vertically, a top plate coupled to an upper end portion of the support structure member to be pivotal between a substantially horizontal position and a substantially vertical folded position, and caster means, disposed at positions near front and rear ends of a lower end portion of the support structure member, for supporting the support structure member, and which supports the caster means at the positions near the front and rear ends of the support structure member, the caster support structure comprising: caster movably supporting means for supporting one of the caster means at the positions near the front and rear ends to move the above described one of the caster means between a projecting position, at which the above described one of the caster means projects from a corresponding one of the positions near the front and rear ends, and a retracted position, at which the above described one of the caster means is retracted and stored in the corresponding one of the positions near the front and rear ends; and interconnecting means, interconnecting the top plate with said caster movably supporting means, for moving the above described one of the caster means from the projecting position.to the retracted position when - 45 the top plate pivots from the J1--1ded position to the horizontal position, and for moving the above described one of the caster means from the retracted position to the projecting position when the top plate pivots from the horizontal position to the folded position.
2. A structure according to claim 1, wherein said caster movably supporting means includes a front-to-rear extending beam extending in the lower end portion of the support structure member in its front-to-rear direction, said front-to-rear extending beam supports the above described one of the caster means at the corresponding one of front and rear end portions thereof, and the other one of the front and rear end portions of said front-to-rear extending beam is is coupled to a corresponding one of the positions near the front and rear ends of the lower end portion of the support structure member to be vertically pivotal to vertically move the above described one of the caster means, and said interconnecting means comprises a thin elongated vertically movable member, verti cally extending in the support structure member, and coupled to the top plate with an upper end portion thereof to be vertically movable in response to the pivotal movement of the top plate between the horizontal position and the folded position, and lever action --.J--.3led to a lower end portion of said vertically movable membeL, for vertically moving said front-torear extending beam of said caster movably supporting means by a lever action upon a vertical movement of said vertically movable member, thereby vertically moving the above described one of the caster means between the retracted position and the projecting position.
3. A structure according to claim 2, wherein the other caster means is supported on the other corresponding one of the front and rear end portions of said front-to-rear extending beam of said caster movably supporting member to project downward.
4. A structure according to claim 2, wherein the above described one of the caster means is sup- ported on the rear end portion of said front-torear extending beam of said caster movably supporting means, and the front end portion of said front-to-rear extending beam is coupled to the position near the front end of the lower end portion of the support structure member to be vertically pivotal around the position near the front end.
5. A structure according to claim 4, wherein the other caster means is supported on the front end portion of said front-to-rear extending beam of said caster movably supporting means to project downward.

47 -
6. A structure according to claim 1, wherein an antiskid member is supported on one of the positions near the front and rear ends of the lower end portion of the support structure member that corresponds to the above described one of the caster means, and the above described one of the caster means pro- jects downward beyond said antiskid member when the above described one of the caster means is set at the projecting position, and is retracted above said antiskid member when the above described one of the caster means is set at the retracted position.
7. A structure according to claim 1, wherein said caster movably supporting means supports the above described one of the caster means at the corre sponding one of the positions near the front and rear ends of the lower end portion of the support structure member to make the above described one of the caster means pivot vertically between the projecting position and the retracted position, and said interconnecting means comprises a thin elongated vertically movable member, verti cally extending in the support structure member, and coupled to the top plate with an upper end portion thereof to be vertically movable in the support struc ture member in response to the pivotal moveme.-,t of the top plate between the horizontal position and the folded position, and is link means, having one end coupled to a lower end portion of said vertically movable member and the other end coupled to said caster movably supporting means, for making said caster movably supporting means pivot verti- cally by a vertical movement of said vertically movable member, thereby moving the above described one of the caster means between the projecting position and the retracted position.
8. A structure according to claim 7, wherein said caster movably supporting means has an antiskid member, said antiskid member being retracted above the above described one of the caster means when the above described one of the caster means is set at the projecting position, and being projecting downward beyond the above described one of the caster means when the above described one of the caster means is set at the retracted position.
9. A structure according to claim 7, wherein said caster movably supporting means supports the above described one of the caster means at the position near the rear end of the lower end portion of the support structure member to make the above described one of the caster means pivot vertically between the projecting position and the retracted position.
10. A structure according to claim 1, wherein said caster movably supporting means further suDports the other cas-i-.- - ,.e-3ns at the other one of the - 49 positions near the front and rear ends of the lower end portion of the support structure member to move the other caster means between a projecting position, at which the other caster means projects downward from the corresponding other one of the positions near the front and rear ends of the lower end portion of the support structure member, and a retracted position, at which the other caster means is retracted and stored in the corre sponding other one of the positions near the front and rear ends of the lower end portion of the support struc ture member, and said interconnecting means also interconnects the top plate with said caster movably supporting means to move the other caster means from the projecting position is to the retracted position when the top plate pivots from the folded position to the horizontal position, and to move the other caster means from the retracted position to the projecting position when the top plate pivots from the horizontal position to the folded position.
11. A structure according to claim 10, wherein said caster movably supporting means supports both of the caster means at both of the positions near the front and rear ends of the lower end portion of the sup port structure member to make both of the caster means pivot vertically between the projecting positions and the retracted positions, and said interconne:----..g -eans comprises - so is a thin elongated vertically movable member, vertically extending in the support structure member, and coupled to the top plate at an upper end portion thereof to be vertically movable in the support structure member in response to the pivotal movement of the top plate between the horizontal position and the folded position, and link member, coupled to a lower end portion of said vertically movable member and said caster movably sup- porting means, for making said caster movably supporting means pivot vertically by a vertical movement of said vertically movable member, thereby moving both of the caster means between the projecting positions and the retracted positions.
12. A structure according to claim 10, wherein said caster movably supporting means has antiskid members to correspond to both of the caster means, said antiskid members being retracted above both of the caster means when both of the caster means are set at the projecting positions, and being projecting downward beyond both of the caster means when both of the caster means are set at the retracted positions.
13. A movable table comprising: a support structure member extending substantially vertically; a top plate coupled to an upper e.n.d portion of said support structu----:-ember to be pivotal between 1 51 - a substantially horizontal position and a substantially vertical folded position; caster means, disposed at positions near front and rear ends of a lower end portion of said support structure member, for supporting said support structure member; caster movably supporting means for supporting one of said caster means at the corresponding one of the positions near the front and rear ends to move the above described one of said caster means between a projecting position, at which the above described one of said caster means projects from the corresponding one of the positions near the front and rear ends, and a retracted position, at which the above described one of said is caster means is retracted and stored in a corresponding one of the positions near the front and rear ends; and interconnecting means, interconnecting said top plate with said caster movably supporting means, for moving the above described one of said caster means from the projecting position to the retracted position when said top plate pivots from the folded position to the horizontal position, and for moving the above described one of said caster means from the retracted position to the projecting position when said top plate pivots from the horizontal position to the folded position.
14. A movable table according to claim 13, wherein said caster move,-',,, supporting means includes - 52 a front-to-rear extending beam extending in the lower end portion of said support structure member in the front-to-rear direction, said front-to- rear extending beam supports the above described one of said caster means at a corresponding one of front and rear end por tions thereof, and the other one of the front and rear end portions of said front-to-rear extending beam is vertically pivotally coupled to a corresponding one of the positions near the front and rear ends of the lower end portion of said support structure member to vert-i cally move the above described one of said caster means, and said interconnecting means comprises a thin elongated vertically movable member, verti is cally extending in said support structure member, and coupled to said top plate with an upper end portion thereof to be vertically movable in said support structure member in response to the pivotal movement of said top plate between the horizontal position and the folded position, and lever action means, coupled to a lower end portion of said vertically movable member, for vertically moving said fronttorear extending beam of said caster movably supporting means by a lever action upon a vertical move- ment of said vertically movable member, -'.-hereby vertically moving the above described one of said caster means between the re-'------ted position and the projecting 7 53 - position.
15. A movable table according to claim 13, wherein the other caster means is supported on the other corresponding one of said front and rear end portions of said frontto-rear extending beam of said caster movably supporting member to project downward.
16. A movable table according to claim 13, wherein an antiskid member is supported on one of the positions near the front and rear ends of the lower end por- tion of said support structure member that corresponds to the above described one of said caster means, and the above described one of the caster means T)ro jects downward beyond said antiskid member when the above described one of the caster means is set at the projecting position, and is retracted above said antiskid member when the above described one of said caster means is set at the retracted position.
17. A movable table according to claim 13, wherein said caster movably supporting means supports the above described one of said caster means at the corresponding one of the positions near the front and rear ends of the lower end portion of said support structure member to vertically pivot the above described one of said caster means between the projecting position and the retracted position, and said interconnecting means comprises a thin elongate' -;-rtically movable member, 54 - is vertically extending in said support structure member, and coupled to said top plate with an upper end portion thereof to be vertically movable in said support struc ture member in response to the pivotal movement of said top plate between the horizontal position and the fold ing position, and link means, having one end coupled to a lower end portion of said vertically movable member and the other end coupled to said caster movably supporting means, for making said caster movably supporting means pivot verti cally by a vertical movement of said vertically movable member, thereby moving the above described one of said caster means between the projecting position and the retracted position.
18. A movable table according to claim 17, wherein said caster movably supporting means has an antis kid member, said antiskid member being retracted above the above described one of said caster means when the above described one of the caster means is set at the projecting position and being projecting downward beyond the above described one of said caster means when the above described one of said caster means is set at the retracted position.
19. A movable table according to claim 13, wherein said caster movably supporting means further sup ports said other caster means at the other one of the positions near the front and rear ends of the lower. end portion of said support structure member to move said other caster means between a projecting position, at which said other caster means projects downward from the corresponding other one of the positions near the front and rear ends of the lower end portion of said support structure member, and a retracted position, at which said other caster means is retracted and stored in the corresponding other one of the positions near the front and rear ends of the lower end portion of said support structure member, and said interconnecting means also interconnects said top plate with said caster movably supporting means to move said other caster means from the projecting posi tion to the retracted position when said top plate pivots from the folded position to the horizontal position, and to move said other caster means from the retracted position to the projecting position when said top plate pivots from the horizontal position to the folded position.
20. A movable table according to claim 19, wherein said caster movably supporting means supports both of said caster means at both of the positions near the front and rear ends of the lower end portion of said support structure member to make both of said caster means pivot vertically between the projecting positions and the retracted positions, and said interconnect4ng means comprises - sc - is a thin elongated vertically movable member, vertically extending in said support structure member, and coupled to said top plate at an upper end portion thereof to be vertically movable in said support structure member in response to the pivotal movement of said top plate between the horizontal position and the folded position, and link means, coupled to a lower end portion of said vertically movable member and said caster movably sup porting means, for making said caster movably supporting means pivot vertically by a vertical movement of said vertically movable member, thereby moving both of said caster means between the projecting positions and the retracted positions.
21. A movable table according to claim 19, wherein said caster movably supporting means has antiskid members to correspond to both of said caster means, said antiskid members being retracted above both of said caster means when both of said caster means are set at the projecting positions, and being projecting downward beyond both of said caster means when both of said cas ter means are set at the retracted positions.
22. A caster support structure and movable table having the same, substantially as hereinbefore described with reference to the accompanying drawings.