MULTI-ROD SUPPORT DEVICE WITH AN ENLARGED CARRYING SURFACE

Abstract

A multi-rod support device includes a pivot seat unit, a support unit and a carrying unit. The pivot seat unit defines a central axis. The support unit is pivotably connected with the pivot seat unit, and includes a first rod and two second rods turnable relative to the pivot seat unit between a folded state and an unfolded state. The carrying unit includes a central plate, two lateral plates and two extension plates. Each extension plate is movable relative to the corresponding lateral plate between a retreat state and an extend state. In the extend state of the extension plates, upper end portions of the second rods abut against a bottom portion of the carrying unit to form an enlarged carrying surface on the carrying unit.

Description

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to Taiwanese Patent Application No. 114104036, filed on February 4, 2025, and incorporated by reference herein in its entirety.

FIELD

The disclosure relates to a moving seat device, and more particularly to a multi-rod support device with an enlarged carrying surface.

BACKGROUND

A conventional folding crutch chair disclosed in TWM613818 includes a stem unit, a seat unit and a support unit. The seat unit and the support unit are respectively and pivotably disposed on two opposite sides of the stem unit. The stem unit has a base shaft and a slide shaft disposed on an upper end of the base shaft. The base shaft has an elongated slot extending therealong. The seat unit includes a seat plate pivotably connected with the base shaft, and a slide sleeve pivotably connected with the seat plate and slidably sleeved on the slide shaft. The support unit includes a first leg and a second leg which are foldable and unfoldable relative to the stem unit and are received in the elongated slot of the base shaft when folded.

The folding crutch chair is shiftable between a crutch using state and a chair using state. However, with the seat plate of a single piece which is not foldable, the seat plate takes a larger space and hinders the user from walking when the folding crutch chair is in the crutch using state. On the other hand, the carrying surface of the seat plate is not sufficient to provide the user with a comfortable seat.

SUMMARY

Therefore, an object of the disclosure is to provide a multi-rod support device with an enlarged carrying surface that can alleviate at least one of the drawbacks of the prior art.

According to the disclosure, the multi-rod support device with an enlarged carrying surface includes a pivot seat unit, a support unit and a carrying unit. The pivot seat unit has a through hole which defines a central axis. The support unit is pivotably connected with the pivot seat unit, and includes a first rod and two second rods. Each of the first rod and the second rods has an upper end portion and a lower end portion opposite to the upper end portion. The upper end portions and the lower end portions are turnable relative to the pivot seat unit between a folded state, where the upper end portions and the lower end portions are close to the central axis, and an unfolded state where the upper end portions and the lower end portions are remote from the central axis. The carrying unit includes a central plate which is pivotably connected with the first rod, two lateral plates which are respectively and pivotably connected with two lateral edges of the central plate, and two extension plates which are respectively and movably connected with the two lateral plates. Each of the extension plates is movable relative to a corresponding one of the lateral plates between a retreat state and an extend state. During turning of the upper end portions and the lower end portions from the folded state to the unfolded state, the extension plates are moved relative to the lateral plates and are shifted from the retreat state to the extend state, where the upper end portions of the two second rods abut against a bottom portion of the carrying unit.

With each extension plate extending relative to the corresponding lateral plate in the extend state, an enlarged carrying surface is formed by the carrying unit for a comfortable sitting experience. The extension plates are shiftable relative to the lateral plates to the retreat state so that the carrying unit may be folded into a smaller volume to facilitate carriage and storage of the device.

BRIEF DESCRIPTION OF THE DRAWINGS

Other features and advantages of the disclosure will become apparent in the following detailed description of the embodiments with reference to the accompanying drawings. It is noted that various features may not be drawn to scale.

FIGS. 1 and 2 are perspective views illustrating a first embodiment of a multi-rod support device according to the disclosure.

FIG. 3 is an exploded perspective view of the first embodiment.

FIG. 4 is a sectional view taken along line IV-IV of FIG. 1.

FIGS. 5(A), 5(B), 5(C), 5(D) and 5(E) are schematic views illustrating the operation of the first embodiment.

FIG. 6 is a sectional view of the first embodiment in a modified form.

FIG. 7 is a perspective view illustrating a second embodiment of a multi-rod support device according to the disclosure.

FIG. 8 is a fragmentary, exploded perspective view of the second embodiment.

FIG. 9 is a sectional view taken along line IX-IX of FIG. 7.

FIGS. 10(A), 10(B), 10(C), 10(D), 10(E) and 10(F) are schematic views illustrating the operation of the second embodiment.

FIG. 11 is a perspective view illustrating a third embodiment of a multi-rod support device according to the disclosure.

FIG. 12 is a fragmentary, exploded perspective view of the third embodiment.

FIG. 13 is a sectional view taken along line XIII-XIII of FIG. 11.

FIGS. 14(A), 14(B), 14(C), 14(D), 14(E) and 14(F) are schematic views illustrating the operation of the third embodiment.

FIG. 15 is a perspective view illustrating a fourth embodiment of a multi-rod support device according to the disclosure.

FIG. 16 is an exploded perspective view of the fourth embodiment.

FIG. 17 is a sectional view taken along line XVII-XVII of FIG. 15.

FIGS. 18(A), 18(B), 18(C), 18(D), 18(E) and 18(F) are schematic views illustrating the operation of the fourth embodiment.

FIG. 19 is a schematic view illustrating a fifth embodiment of a carrying unit of a multi-rod support device according to the disclosure.

FIG. 20 is a schematic view illustrating the carrying unit in an extend state.

FIG. 21 is a schematic view illustrating a sixth embodiment of a carrying unit of a multi-rod support device according to the disclosure.

FIG. 22 is a schematic view illustrating the carrying unit in an extend state.

DETAILED DESCRIPTION

Before the disclosure is described in greater detail, it should be noted that where considered appropriate, reference numerals or terminal portions of reference numerals have been repeated among the figures to indicate corresponding or analogous elements, which may optionally have similar characteristics.

It should be noted herein that for clarity of description, spatially relative terms such as “top,” “bottom,” “upper,” “lower,” “on,” “above,” “over,” “downwardly,” “upwardly” and the like may be used throughout the disclosure while making reference to the features as illustrated in the drawings. The features may be oriented differently (e.g., rotated 90 degrees or at other orientations) and the spatially relative terms used herein may be interpreted accordingly.

Referring to FIGS. 1 to 4, a first embodiment of a multi-rod support device according to the disclosure includes a pivot seat unit 10, a support unit 20 and a carrying unit 30.

The pivot seat unit 10 includes a pivot ring 11 having a through hole 110 which defines a central axis (L), and three pivot axles 12 disposed on the pivot ring 11 and angularly spaced apart from one another about the central axis (L).

The support unit 20 is pivotably connected with the pivot seat unit 10, and includes a first rod 21 and two second rods 22 respectively and pivotably connected with the pivot axles 12. Each of the first rod 21 and the second rods 22 has an upper end portion 201 and a lower end portion 202 opposite to the upper end portion 201. The upper end portions 201 and the lower end portions 202 of the first rod 21 and the second rods 22 are turnable relative to the pivot seat unit 10 between a folded state (as shown in FIG. 5(A)), where the upper end portions 201 and the lower end portions 202 are close to the central axis (L), and an unfolded state (as shown in FIG. 1 and FIG. 5(E)), where the upper end portions 201 and the lower end portions 202 are remote from the central axis (L).

The carrying unit 30 includes a slide seat 31 which is slidably sleeved around the first rod 21, a central plate 32 which is pivotably connected with the slide seat 31, two lateral plates 33 which are respectively and pivotably connected with two lateral edges 323 of the central plate 32, and two extension plates 34 which are respectively and slidably connected with the lateral plates 33. The slide seat 31 has a sleeve 311 sleeved around the first rod 21, and a pair of first lugs 312 extending radially from the sleeve 311. The central plate 32 has a central plate body 321 and a second lug 322 extending downwardly from the central plate body 321 and pivotably connected with the first lugs 312. The central plate body 321 has the two lateral edges 323 and two inner pivot assemblies 324 respectively disposed on the lateral edges 323. Each lateral plate 33 has a lateral plate body 331 and two rack plate bodies 332 disposed below a bottom portion of the lateral plate body 331 and cooperating with the lateral plate body 331 to define a slide rail 333 therebetween. The lateral plate body 331 has an inner side edge 334 which is pivotably connected with the corresponding lateral edge 323 of the central plate 32, an outer side edge 335 which is opposite to the inner side edge 334, an outer stop portion 336 which protrudes from the outer side edge 335, an outer pivot assembly 337 which is disposed on the inner side edge 334, and a pair of keys 338 which are disposed adjacent to the outer side edge 335 and extend transverse to the slide rail 333. The keys 338 are rivets in this embodiment. The outer stop portion 336 is in the form of a rib protruding toward the corresponding extension plate 34. The outer pivot assembly 337 is in pivotable engagement with the corresponding inner pivot assembly 324 of the central plate 32. The slide rail 333 extends from the inner side edge 334 toward the outer side edge 335.

Each extension plate 34 is shiftable relative to the corresponding lateral plate 33 between a retreat state and an extend state. Each extension plate 34 is in slidable engagement with the corresponding slide rail 333, and has a proximal side edge 341, a remote side edge 342 opposite to the proximal side edge 341, a bottom surface 343 extending from the proximal side edge 341 to the remote side edge 342, a top surface 344 opposite to the bottom surface 343, an inner stop portion 345 formed adjacent to the proximal side edge 341 and protruding from the top surface 344, a pair of key slots 346 formed through the extension plate 34 and extending from the proximal side edge 341 toward the remote side edge 342 such that the keys 338 are in slidable engagement with the key slots 346, respectively, and an abutting portion 347 protruding from the bottom surface 343. The inner stop portion 345 is stopped by the outer stop portion 336 to prevent removal of the extension plate 34 from the corresponding lateral plate 33. In the embodiment, the abutting portion 347 of one extension plate 34 is disposed on the bottom surface 343 adjacent to the proximal side edge 341 while the abutting portion 347 of the other extension plate 34 is disposed on a middle portion of the bottom surface 343.

In operation, referring to FIG. 5(A) which illustrates that the extension plates 34 are in the retreat state relative to the corresponding lateral plates 33, the lateral plates 33 are inclined relative to the central plate 32 such that the lateral plates 33 and the central plate 32 cooperatively form an inverted U-shaped profile. Additionally, the upper end portions 201 and the lower end portions 202 of the first rod 21 and the second rods 22 are in the folded state to be close to the central axis (L), and the support unit 20 is surrounded by the lateral plates 33 and the central plate 32 of the carrying unit 30.

With reference to FIGS. 5(A) to 5(E) and FIG. 1, when the user operates to move the slide seat 31 from the upper end portion 201 of the first rod 21 toward the lower end portion 202, and bring the upper end portions 201 of the second rods 22 to gradually move away from the central axis (L), the upper end portions 201 of the second rods 22 are in slidable and abutting engagement with bottom or side portions of the extension plates 34 such that the upper end portions 201 of the second rods 22 are in abutting engagement with the abutting portions 347 and press the abutting portions 347 of the extension plates 34. That is to say, when the extension plates 34 are in the extend state, the upper end portions 201 of the second rods 22 are in the unfolded state and abut against the abutting portions 347 of the extension plates 34. As shown in FIG. 5(E), FIG. 1 and FIG. 4, in this state, the extension plates 34, the lateral plates 33 and the central plate 32 cooperatively define a maximum carrying surface that provides a comfortable sitting surface.

When the user operates to move the slide seat 31 toward the upper end portion 201 of the first rod 21, and bring the upper end portions 201 of the second rods 22 to gradually move close to the central axis (L), the extension plates 34, the lateral plates 33 and the central plate 32 are gradually folded.

Thus, in this embodiment, the extension plates 34 extend relative to the lateral plates 33 in the extend state to form a larger carrying surface and provide a comfortable sitting surface. Moreover, with the extension plates 34 retreated relative to the lateral plates 33 in the retreat state, and the lateral plates 33 and the central plate 32 cooperatively forming an inverted U-shaped profile, the carrying unit 30 may be folded into a smaller volume to facilitate carriage and storage of the device.

With reference to FIG. 6, in a modified form of the embodiment, the abutting portion 347 of each extension plate 34 is disposed on a middle portion of the bottom surface 343 such that the abutting portions 347 are symmetrical to each other.

With reference to FIGS. 7 to 9, in a second embodiment, the multi-rod support device includes a pivot seat unit 10, a support unit 20 and a carrying unit 30.

The support unit 20 includes a first rod 21, two second rods 22 and a third rod 23. The third rod 23 has an upper end portion 201 and a lower end portion 202 opposite to the upper end portion 201. The upper end portion 201 of the third rod 23 is pivotably connected with the central plate 32. Additionally, the upper end portion 201 of each second rod 22 has a ball joint 221 which has a neck section 222 and an enlarged ball section 223.

The carrying unit 30 includes a slide seat 31, a central plate 32, two lateral plates 33 and two extension plates 34. The central plate 32 further has a pivot lug 325 disposed at one lateral edge 323 of the central plate body 321 such that the upper end portion 201 of the third rod 23 is pivotably connected with the pivot lug 325. Moreover, each lateral plate 332 has only one rack plate body 332 which extends along a lengthwise direction (X) of the lateral plate 332, and three keys 338 which are spaced apart from one another in the lengthwise direction (X). Each extension plate 34 has three key slots 346 spaced apart from one another in the lengthwise direction (X), and an abutting portion 347 extending from the remote side edge 342 and transverse to the lengthwise direction (X) to define a coupling slot 347’ for receiving the ball section 223 therein.

With reference to FIGS. 10(A) to 10(F) and FIG. 9, the extension plates 34 are operably and gradually moved relative to the lateral plates 33 from the retreat state to the extend state. During this movement of the extension plates 34, the upper end portions 201 of the second rods 22 are in abutting engagement with and press the abutting portions 347 of the extension plates 34. When the extension plates 34 are in the extend state, the extension plates 34, the lateral plates 33 and the central plate 32 cooperatively define a maximum carrying surface to provide a comfortable sitting surface. Also, the ball sections 223 of the second rods 22 are retainingly engaged in the coupling slots 347’ defined by the abutting portions 347.

Moreover, with the upper end portion 201 of the third rod 23 pivotably connected with the central plate 32, and the first rod 21 and the second rods 22 supporting the carrying unit 30 at different parts of the carrying unit 30, the support unit 20 may support the carrying unit 30 firmly.

With reference to FIGS. 11 to 13, in a third embodiment, the multi-rod support device also includes a pivot seat unit 10, a support unit 20 and a carrying unit 30.

Each extension plate 34 of the carrying unit 30 has a plate body 340. The plate body 340 has a proximal side edge 341, a remote side edge 342 opposite to the proximal side edge 341, a bottom surface 343 extending from the proximal side edge 341 to the remote side edge 342, a top surface 344 opposite to the bottom surface 343, an inner stop portion 345 formed adjacent to the proximal side edge 341 and protruding from the top surface 344, two sets of key slots 346 formed through the extension plate 34 and extending from the proximal side edge 341 toward the remote side edge 342 such that the keys 338 are in slidable engagement with the key slots 346, respectively, an abutting portion 347 formed on the bottom surface 343, and an anchoring piece 340” connected with the remote side edge 342. The abutting portion 347 is in the form of an elongated slot 347 which extends in and is inclined relative to the bottom surface 343. Additionally, each second rod 22 has an L-shaped seat 224 which is pivotably connected with the upper end portion 201 of the second rod 22, and a U-shaped seat 225 which is in slidable engagement with the elongated slot 347 and is pivotably connected with the L-shaped seat 224. Specifically, the L-shaped seat 224 has a seat connecting axle 226 and a rod connecting axle 227 transverse to each other. The U-shaped seat 225 is pivotably connected with the seat connecting axle 226. The upper end portion 201 of each second rod 22 is pivotably connected with the rod connecting axle 227.

With reference to FIGS. 14(A) to 14(F) and FIG. 13, the extension plates 34 are operably and gradually moved relative to the lateral plates 33 from the retreat state to the extend state. During this movement of the extension plates 34, the upper end portions 201 of the second rods 22 bring the L-shaped seats 224 to pivot relative to the U-shaped seats 225, and bring the U-shaped seats 225 to slide along the elongated slots 347 to synchronously bring the extension plates 34 to slide relative to the lateral plates 33. Hence, when the extension plates 34 are in the extend state, the extension plates 34, the lateral plates 33 and the central plate 32 cooperatively define a maximum carrying surface to provide a comfortable sitting surface. Also, as shown in FIG. 14(A), when the extension plates 34 are in the retreat state, the lateral plates 33 are inclined relative to the central plate 32, and the anchoring pieces 340” are engaged with each other so as to prevent undesired unfolding of the carrying unit 30.

With reference to FIGS. 15 to 17, in a fourth embodiment, the multi-rod support device includes a pivot seat unit 10, a support unit 20, a carrying unit 30, and an operation synchronizing unit 40 connected with the carrying unit 30 and the support unit 20.

The central plate 32 of the carrying unit 30 has an engaging slot 326, an abutting protrusion 327 formed adjacent to the engaging slot 326, a third lug 328 opposite to the second lug 322, a pivot tab 329, and a linkage assembly 320. The linkage assembly 320 has a first linking bar 320’ and a second linking bar 320”. The first linking bar 320’ has a lower end pivotably connected with the pivot seat unit 10, and an upper end formed with a slide slot 301. The second linking bar 320” has an end pivotably connected with the first linking bar 320’ and slidably engaged with the slide slot 301, and an opposite end pivotably connected with the third lug 328 of the central plate 32. Additionally, the carrying unit 30 further includes at least one second biasing member 35 which is connected between the extension plates 34. That is to say, two ends of the second biasing member 35 are respectively engaged with the extension plates 34 to bias the extension plates 34 to move closer to each other. Each extension plate 34 has an anchoring piece 340”.

The operation synchronizing unit 40 is operated to synchronously turn the upper end portions 201 and the lower end portions 202 of the first rod 21 and the second rods 22 from the folded state to the unfolded state, and includes a connecting stem 41, a plurality of lower linking bars 42 and a first biasing member 43. The connecting stem 41 extends along the central axis (L) through the through hole 110 of the pivot ring 11. Each lower linking bar 42 pivotably interconnects the connecting stem 41 and a respective one of the first rod 21 and the second rods 22. The first biasing member 43 is sleeved around the connecting stem 41 and has two ends abutting against the pivot seat unit 10 and a lower end of the connecting stem 41. The connecting stem 41 is pivotably connected with the pivot tab 329 of the central plate 32. The first biasing member 43 is in the form of a compression spring.

With reference to FIGS. 18(A) to 18(F) and FIG. 17, when the user operates to move the slide seat 31 from the upper end portion 201 of the first rod 21 toward the lower end portion 202, and bring the central plate 32 to be inclined relative to the first rod 21, the connecting stem 41 is moved along the central axis (L) to actuate the lower linking bars 42 from a close state to a spread state, which synchronously brings the upper end portions 201 and the lower end portions 202 of the first rod 21 and the second rods 22 to be turned from the folded state to the unfolded state. Also, when the anchoring members 340” are released, the lower linking bars 42 are shiftable from the close state to the spread state by the biasing action of the first biasing member 43. During turning of the upper end portions 201 and the lower end portions 202 from the folded state to the unfolded state, the extension plates 34 slide relative to the lateral plates 33 and are shifted from the retreat state to the extend state, where the upper end portions 201 of the second rods 22 abut against the bottom portion of the carrying unit 30.

Moreover, when the extension plates 34 are in the extend state, the upper end of the first linking bar 320’ is slidably engaged in the engaging slot 326 to abut against the abutting protrusion 327 so as to firmly support the carrying unit 30. It is noted that the linkage assembly 320 may be dispensed with.

With reference to FIGS. 19 and 20, in a fifth embodiment, each extension plate 34’ of the carrying unit 30’ is rotatably connected with the corresponding lateral plate 33’, and has a shape of a fan. Specifically, each lateral plate 33’ has a shape of a fan so as to have a pivoting portion 339’ at a narrow end thereof. The pivoting portion 339’ is in the form of a round hole. Each extension plate 34’ has a narrow end 349’ which is pivotably connected with the pivoting portion 339’. Thus, each extension plate 34’ is shiftable relative to the corresponding lateral plate 33’ between the retreat state (as shown in FIG. 19) and the extend state (as shown in FIG. 20).

With reference to FIGS. 21 and 22, in a sixth embodiment, each extension plate 34” of the carrying unit 30” is rotatably and slidably connected with the corresponding lateral plate 33”, and has a shape of a fan. Specifically, each lateral plates 33” has a shape of a fan so as to have a pivoting portion 339” at a narrow end thereof. The pivoting portion 339” is in the form of an elliptical hole. Each extension plate 34” has a narrow end 349” which is pivotably and slidably connected with the pivoting portion 339”. Thus, each extension plate 34” is shiftable relative to the corresponding lateral plate 33” between the retreat state (as shown in FIG. 21) and the extend state (as shown in FIG. 22).

As illustrated, the multi-rod support device of the disclosure has a simple structure, and is easy to operate to form an enlarged carrying surface to provide a comfortable sitting surface. The extension plates are shiftable relative to the lateral plates to the retreat state so that the carrying unit may be folded into a smaller volume to facilitate carriage and storage of the device.

In the description above, for the purposes of explanation, numerous specific details have been set forth in order to provide a thorough understanding of the embodiments. It will be apparent, however, to one skilled in the art, that one or more other embodiments may be practiced without some of these specific details. It should also be appreciated that reference throughout this specification to “one embodiment,” “an embodiment,” an embodiment with an indication of an ordinal number and so forth means that a particular feature, structure, or characteristic may be included in the practice of the disclosure. It should be further appreciated that in the description, various features are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of various inventive aspects; such does not mean that every one of these features needs to be practiced with the presence of all the other features. In other words, in any described embodiment, when implementation of one or more features or specific details does not affect implementation of another one or more features or specific details, said one or more features may be singled out and practiced alone without said another one or more features or specific details. It should be further noted that one or more features or specific details from one embodiment may be practiced together with one or more features or specific details from another embodiment, where appropriate, in the practice of the disclosure.

While the disclosure has been described in connection with what are considered the exemplary embodiments, it is understood that this disclosure is not limited to the disclosed embodiments but is intended to cover various arrangements included within the spirit and scope of the broadest interpretation so as to encompass all such modifications and equivalent arrangements.

Claims

1. A multi-rod support device, comprising:

a pivot seat unit having a through hole which defines a central axis;

a support unit pivotably connected with said pivot seat unit, and including a first rod and two second rods, each of said first rod and said second rods having an upper end portion and a lower end portion opposite to said upper end portion, said upper end portions and said lower end portions being turnable relative to said pivot seat unit between a folded state, where said upper end portions and said lower end portions are close to the central axis, and an unfolded state where said upper end portions and said lower end portions are remote from the central axis; and

a carrying unit including a central plate which is pivotably connected with said first rod, two lateral plates which are respectively and pivotably connected with two lateral edges of said central plate, and two extension plates which are respectively and movably connected with said two lateral plates, each of said extension plates being movable relative to a corresponding one of said lateral plates between a retreat state and an extend state, wherein, during turning of said upper end portions and said lower end portions from the folded state to the unfolded state, said extension plates are moved relative to said lateral plates and are shifted from the retreat state to the extend state, where said upper end portions of said two second rods abut against a bottom portion of said carrying unit.

2. The multi-rod support device of claim 1, wherein each of said two lateral plates has an inner side edge which is pivotably connected with a corresponding one of said lateral edges of said central plate, an outer side edge which is opposite to said inner side edge, an outer stop portion which protrudes from said outer side edge, and a slide rail which extends from said inner side edge toward said outer side edge, each of said two extension plates being in slidable engagement with said slide rail and having an inner stop portion which is stopped by said outer stop portion.

3. The multi-rod support device of claim 2, wherein each of said two extension plates has a bottom surface and an abutting portion which is formed on said bottom surface such that said upper end portion of a corresponding one of said second rods is in abutting engagement with said abutting portion when said extension plates are in the extend state.

4. The multi-rod support device of claim 3, wherein each of said two lateral plates further has at least one pair of keys extending transverse to said slide rail, each of said two extension plates further having at least one pair of key slots which are formed therethrough such that said keys are in slidable engagement with said key slots, respectively.

5. The multi-rod support device of claim 1, wherein said upper end portions of said two second rods are in slidably abutting engagement with bottom portions of said extension plates, respectively.

6. The multi-rod support device of claim 3, wherein said support unit further includes a third rod, said third rod having an upper end portion and a lower end portion opposite to said upper end portion, said upper end portion of said third rod being pivotably connected with said central plate, said upper end portion of each of said two second rods having a ball joint which has a neck section and an enlarged ball section, said abutting portion of each of said two extension plates defining a coupling slot for receiving said ball section therein.

7. The multi-rod support device of claim 3, wherein each of said two extension plates has a plate body having said bottom surface, said abutting portion being in form of an elongated slot which extends in and is inclined relative to said bottom surface, each of said two second rods further having an L-shaped seat which has a seat connecting axle and a rod connecting axle that are transverse to each other, and a U-shaped seat which is pivotably connected with said seat connecting axle and which is in slidable engagement with said elongated slot, said upper end portion of each of said two second rods being pivotably connected with said rod connecting axle.

8. The multi-rod support device of claim 1, further comprising an operation synchronizing unit connected with said carrying unit and said support unit, and operated to synchronously turn said upper end portions and said lower end portions of said first rod and said second rods from the folded state to the unfolded state.

9. The multi-rod support device of claim 8, wherein said carrying unit further includes a slide seat which is slidably sleeved around said first rod and is pivotably connected with said central plate, said operation synchronizing unit including a connecting stem which is pivotably connected with said central plate and which extends along the central axis, and a plurality of lower linking bars each of which pivotably interconnects said connecting stem and a respective one of said first rod and said second rods such that, when said slide seat is operably moved from said upper end portion of said first rod toward said lower end portion to bring said central plate to be inclined relative to said first rod, said connecting stem is moved along the central axis to actuate said lower linking bars from a close state to a spread state, which synchronously brings said upper end portions and said lower end portions of said first rod and said second rods to be turned from the folded state to the unfolded state.

10. The multi-rod support device of claim 9, wherein said central plate has an engaging slot and an abutting protrusion formed adjacent to said engaging slot, said carrying unit further including a linkage assembly, said linkage assembly having a first linking bar which has a lower end pivotably connected with said pivot seat unit, and an upper end formed with a slide slot, and a second linking bar which has an end pivotably connected with said first linking bar and slidably engaged with said slide slot, and an opposite end pivotably connected with said central plate, said upper end of said first linking bar being slidably engaged in said engaging slot to abut against said abutting protrusion.

11. The multi-rod support device of claim 9, wherein said operation synchronizing unit further includes a first biasing member which is sleeved around said connecting stem and which has two ends abutting against said pivot seat unit and said lower end of said connecting stem to bias said lower linking bars from the close state to the spread state.

12. The multi-rod support device of claim 1, wherein each of said two extension plates has a remote side edge and an anchoring piece connected with said remote side edge such that, when said extension plates are in the retreat state, said lateral plates are inclined relative to said central plate and said anchoring pieces are engaged with each other.

13. The multi-rod support device of claim 1, wherein each of said two extension plates has a proximal side edge, a remote side edge opposite to said proximal side edge, a bottom surface extending from said proximal side edge to said remote side edge, a top surface opposite to said bottom surface, and an abutting portion formed on said bottom surface, said abutting portion being in form of an elongated slot which extends in and is inclined relative to said bottom surface; each of said two second rods further having an L-shaped seat which has a seat connecting axle and a rod connecting axle that are transverse to each other, and a U-shaped seat which is pivotably connected with said seat connecting axle and which is in slidable engagement with said elongated slot, said upper end portion of each of said two second rods being pivotably connected with said rod connecting axle; wherein said extension plates is operably and gradually moved relative to said lateral plates from the retreat state to the extend state, and, during movement of said extension plates to the extend state, said upper end portions of said second rods bring said L-shaped seats to pivot relative to said U-shaped seats, and bring said U-shaped seats to slide along said abutting portions to synchronously bring said extension plates to slide relative to said lateral plates such that, when said extension plates are in the extend state, said extension plates, said lateral plates and said central plate cooperatively define a maximum carrying surface.

14. The multi-rod support device of claim 1, wherein said carrying unit further includes at least one second biasing member which is connected between said two extension plates to bias said two extension plates to move closer to each other.

15. The multi-rod support device of claim 1, wherein each of said two extension plates is rotatably connected with a corresponding one of said lateral plates, and has a shape of a fan, each of said lateral plates having a shape of a fan so as to have a pivoting portion at a narrow end thereof, said pivoting portion being in form of a round hole, each of said two extension plates having a narrow end which is pivotably connected with said pivoting portion.

16. The multi-rod support device of claim 1, wherein each of said two extension plates is rotatably and slidably connected with a corresponding one of said lateral plates, and has a shape of a fan, each of said lateral plates having a shape of a fan so as to have a pivoting portion at a narrow end thereof, said pivoting portion being in form of an elliptical hole, each of said two extension plates having a narrow end which is pivotably and slidably connected with said pivoting portion.