Expandable chair assembly   

Abstract: A chair assembly has a seat, a backrest and an expandable leg supporting device. The seat has a front end and a rear end. The backrest is connected to the rear end of the seat. The expandable leg supporting device is mounted on the front end of the seat and has a base, at least one extension frame and a frame driving device. The base is mounted securely on the front end of the seat. The least one extension frame is connected to the base. The frame driving device is mounted on the base and is connected to the at least one extension frame to pivot the at least one extension frame relative to the base. Accordingly, the chair assembly can be expanded to support legs of a user in an expanded condition.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a chair, and more particularly to an expandable chair assembly to support legs of a user in an expanded condition.

2. Description of Related Art

Chairs enable person sitting thereon to support the weights of the sitter. A chair substantially comprises a seat and a backrest for support the back of a sitter. The backrest may be adjustable in angle relative to the seat to fit with different needs of different sitters.

However, when a person sits on a chair for a long time, for example in a long vehicle traveling, the legs of the sitter on the convention chair will become tired, numb or pained due to long term of bending. Accordingly, the conventional chair should be further improved to provide an enhanced comforting effect.

To overcome the shortcomings, the present invention tends to provide an extendable chair assembly to mitigate or obviate the aforementioned problems.

SUMMARY

The main objective of the invention is to provide an expandable chair assembly to support legs of a user in an expanded condition. The chair assembly has a seat, a backrest and an expandable leg supporting device. The seat has a front end and a rear end. The backrest is connected to the rear end of the seat. The expandable leg supporting device is mounted on the front end of the seat and has a base, at least one extension frame and a frame driving device. The base is mounted securely on the front end of the seat. The least one extension frame is connected to the base. The frame driving device is mounted on the base and is connected to the at least one extension frame to pivot the at least one extension frame relative to the base.

Other objects, advantages and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an extendable chair assembly in accordance with the present invention;

FIG. 2 is a perspective view of the expandable leg supporting device of the chair assembly in FIG. 1 in an expanded condition;

FIG. 3 is an enlarged perspective view of the frame driving device of the chair assembly in FIG. 1;

FIG. 4 is a partial perspective view of the expandable leg supporting device in FIG. 1;

FIG. 5 is an enlarged perspective view of the panel driving device of the chair assembly in FIG. 1;

FIG. 6 is an enlarged perspective view of the detecting device of the chair assembly in FIG. 1;

FIG. 7 is an operational side view of the expandable leg supporting device of the chair assembly in FIG. 1; and

FIG. 8 is a side view of the expandable leg supporting device of the chair assembly in FIG. 1 in an expanded condition.

DETAILED DESCRIPTION

With reference to FIGS. 1 and 2, an extendable chair assembly in accordance with the present invention comprises a seat 10, a backrest 20 and an expandable leg supporting device 30. The seat 10 has a front end and a rear end. The backrest 20 is connected to the rear end of the seat 10.

The expandable leg supporting device 30 is mounted on the front end of the seat 10 and comprises a base 31, at least one extension frame 33,33A,33B and a frame driving device 32. The base 31 is mounted securely on the front end of the seat 10. The at least one extension frame 33,33A,33B is connected to the base 31. Preferably, three extension frames 33,33A,33B are implemented, are telescopically connected with each other and include an outer extension frame 33, a middle extension frame 33A and an inner extension frame 33B arranged from outside to inside in sequence. Each extension frame 33,33A,33B has a volume gradually increasing from the inner extension frame 33B to the outer extension frame 33, such that a smaller extension frame 33A,33B is mounted in a large extension frame 33,33A. In addition, each extension frame 33,33A,33B has two side panels 332,332A,332B, a rear panel 331,331A,331B and an opened front panel. Each side panel 332,332A,332B has an inner surface facing to each other and an outer surface opposite to each other. The rear panel 331 of the outer extension frame 33 is connected pivotally to the base 31.

The frame driving device 32 is mounted on the base 31 and is connected to the at least one extension frame 33,33A,33B to pivot the at least one extension frame 33,33A,33B relative to the base 31. With further reference to FIG. 3, the frame driving device 32 comprises a driving motor 321, a worn rod 322, a worn gear 323, a pinion 324, a driving gear 325 and a pivotal rod 326. The driving motor 321 is mounted securely on the base 31. The worn rod 322 is connected to and driven by the driving motor 321. The worn gear 323 engages and is driven by the worn rod 322. The pinion 324 is co-axially mounted on the worn gear 323. The driving gear 325 engages the pinion 324. The pivotal rod 326 is co-axially mounted on and protrudes from the driving gear 325, is connected securely to the at least one extension frame 33,33A,33B and is preferably connected securely with the rear panel 331 of the outer extension frame 33.

With further reference to FIG. 4, the outer extension frame 33 has a middle extension driving device 333 comprising a middle motor 334, a middle threaded rod 335 and a middle nut 336. The middle motor 334 is mounted securely on the rear panel 331 of the outer extension frame 33. The middle threaded rod 335 is connected to and driven by the middle motor 334. The middle nut 336 is mounted rotatably around the middle threaded rod 335 and is connected securely to the rear panel 331A of the middle extension frame 33A.

The middle extension frame 33A has an inner extension driving device 333A comprises an inner motor 334A, an inner threaded rod 335A and an inner nut 336A. The inner motor 334A is mounted securely on the rear panel 331A of the middle extension frame 33A. The inner threaded rod 335A is connected to and driven by the inner motor 334A. The inner nut 336A is mounted rotatably around the inner threaded rod 335A and is connected securely to the rear panel 331B of the inner extension frame 33B.

In addition, the outer extension frame 33 has two rails 337 mounted respectively on the inner surfaces of the side panels 332. The middle extension frame 33A has two sliders 338A and two rails 337A. The sliders 338A are mounted respectively on the outer surfaces of the side panels 332A of the middle extension frame 33A and are slidably connected with the rails 337 on the outer extension frame 33. The rails 338A are mounted respectively on the inner surfaces of the side panels 332A of the middle extension frame 33A. The inner extension frame 33B has two sliders 338B mounted respectively on the outer surfaces of the side panels 332B of the inner extension frame 33B and slidably connected with the rails 337A on the middle extension frame 33A.

With further reference to FIG. 5, the expandable leg supporting device 30 further has a foot supporting panel 34 pivotally connected to the inner extension frame 33B. A panel driving device 333B is mounted on the inner extension frame 33B, is connected to the foot supporting panel 34 and has a panel driving motor 334B, a driving pulley 3341B, a driven pulley 335B, a belt 336B and a pivotal axle 3351B. The panel driving motor 334B is mounted on the rear panel 331B of the inner extension frame 33B. The driving pulley 3341B is connected to and driven by the panel driving motor 334B. The driven pulley 335B is mounted rotatably on the inner extension frame 33B. The belt 336B is mounted endlessly around the driving pulley 3341B and the driven pulley 335B. The pivotal axle 3351B is co-axially formed on and protrudes from the driven pulley 335B. In addition, the foot supporting panel 34 has two ends and two pivotal ears 341 formed respectively on the ends of the foot supporting panel 34. One of the pivotal ears 341 is connected securely with the pivotal axle 3341B of the panel driving device 333B, and the other pivotal ear 341 is connected pivotally to the rear panel 331B of the inner extension frame 33B with a pivot.

With reference to FIGS. 4 and 6, the expandable leg supporting device 30 further has a middle detecting device 40 mounted between the outer extension frame 33 and the middle extension frame 33A and comprises a potentiometer 41, a detecting gear 411, a rod mount 42, a rotatable rod 421, two end gears 422,422A and a rack 43. The potentiometer 41 is mounted on one of the side panels 332A of the middle extension frame 33A. The detecting gear 411 is mounted on and connected to the potentiometer 41. The rod mount 42 is mounted securely on the side panel 332A of the middle extension frame 33A. The rotatable rod 421 is mounted rotatably on the rod mount 42 and has two ends respectively protruding out from two sides of the rod mount 42. The end gears 422,422A include a first end gear 442 and a second end gear 422A and are mounted respectively on the ends of the rotatable rod 421. The first end gear 422 engages the detecting gear 411. The rack 43 is mounted securely on the outer extension frame 33 and engages the second end gear 422A.

In addition, an inner detecting device may be mounted between the middle extension frame 33A and the inner extension frame 33B and may have the same components as that of the middle detecting device 40.

To expand the leg supporting device 30, with reference to FIGS. 2 and 7, the driving motor 321 is switched on and drives the worn rod 322 to rotate, and the outer extension frame 33 can be pivoted relative to the base 31 with the transmission of the worn gear 323, the pinion 324, the driving gear 325 and the pivotal rod 326.

With reference to FIG. 4, when the middle motor 334 is switched on, the middle threaded rod 335 is rotated and the middle nut 336 is moved along the middle threaded rod 335 with the threaded engagement between the middle threaded rod 335 and the middle nut 336. Accordingly, the middle extension frame 33A will be moved to extend out of the outer extension frame 33. In addition, with the arrangement of the rails 337 and the sliders 338A between the outer and middle extension frames 33,33A, the movement of the middle extension frame 33A is smooth.

Similarly, with reference to FIG. 2, when the inner motor 334A is switched on, the inner threaded rod 335A is rotated and the inner nut 336A is moved along the inner threaded rod 335A with the threaded engagement between the inner threaded rod 335A and the inner nut 336A. Accordingly, the inner extension frame 33B will be moved to extend out of the middle extension frame 33A. With the arrangement of the rails 337A and the sliders 338B between the middle and inner extension frames 33A,33B, the movement of the inner extension frame 33B is smooth. Accordingly, the extension frames 33,33A,33B of the leg supporting device 30 can be expanded to support the legs of a sitter in an expanded condition.

With reference to FIG. 5, when the panel driving motor 334B is switched on, the foot supporting panel 34 can be pivoted relative to the inner extension frame 33B with the transmission of the driving pulley 3341B, the belt 336B, the driven pulley 335B and the pivotal axle 3351B. Accordingly, the feet of the sitter can step onto the foot supporting panel 34.

With reference to FIG. 6, when the middle extension frame 33A is moved to extend out of the outer extension frame 33, the rod mount 42 will move with the middle extension frame 33A. Consequently, the rotatable rod 421 with the end gears 422,422A will be rotated due to the engagement between the rack 43 and the second end gear 422A, and the detecting gear 411 is also rotated. Accordingly, the potentiometer 41 will be rotated to change the electric resistance of the potentiometer 41. With the change of the electric resistance of the potentiometer 41, the position of the middle extension frame 33A out of the outer extension frame 33 can be detected. The operation of the inner detecting device is the same as that of the middle detecting device 40 and is omitted.

With reference to FIGS. 7 and 8, when the outer extension frame 33 is pivoted relative to the base 31 to a horizontal level and the extension frames 33,33A,33B are expanded from each other, the legs of a sitter sitting on the chair assembly can be put and supported on the expanded extension frames 33,33A,33B and the feet of the sitter can step on the foot supporting panel 34. Accordingly, the legs of the sitter can be completely expanded and excellently supported, such that the comforting effect provided by the chair assembly is enhanced and can be kept for a long time. In addition, the space for arranging and storing the foldable leg supporting device 30 can be reduced while the leg supporting device 30 is not in use.

Even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and function of the invention, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.