Foldable leg rest

• US 8,870,289 B2
• Filed: 03/12/2013
• Issued: 10/28/2014
• Est. Priority Date: 05/25/2012
• Status: Expired due to Fees

• Current Assignee: Wan-Yu Li
• Original Assignee: Wan-Yu Li
• Inventors: Yin, Qing-Kun, Chang, Chin-Chen
• Primary Examiner(s): GABLER, PHILIP F
• Application Number:
  US13/795,869
• Publication Number:
  US 20130313882A1
• Time in Patent Office: 595 Days
• Field of Search: 297/69, 297/70, 297/75, 297/76, 297/423.19, 297/423.26, 297/423.28, 297/423.3
• US Class Current: 297/423.22
• CPC Class Codes: A47C 7/506 of adjustable type
• CPC Class Codes: A47C 7/5066 by rotation
• CPC Class Codes: A47C 7/5068 actuated by linkages
• CPC Class Codes: B60N 2/02253 characterised by the transmission between the electric motor and the seat or seat parts
• CPC Class Codes: B60N 2/995 Lower-leg-rests, e.g. calf-rests

Abstract

A foldable leg rest has a slide base, a first folding assembly, a second folding assembly, a first stage drive mechanism and a second stage drive mechanism. The slide base has a slide frame. The first folding assembly has a first frame pivotally connected to the slide frame. The second folding assembly has a second frame pivotally connected to the first frame. In use, the first stage drive mechanism is operated to drive the first frame to pivot relative to the slide frame and the second stage drive mechanism is operated to drive the second frame to pivot relative to the first frame. Therefore, the legs of a sitter can be stretched and placed on the folding assemblies so as to enhance comfort and minimize fatigue.

Claims

1. A foldable leg rest comprising:

a slide base including;

a slide frame having two sides and a front end; and

two supporting arms respectively slidably mounted on the sides of the slide frame and each supporting arm having;

a front end;

a projection extending from the front end of the supporting arm; and

a rolling bearing and a roller mounted on the projection;

a first folding assembly including;

a first frame having;

a front end;

a rear end pivotally connected to the front end of the slide frame; and

a bottom surface having two side portions; and

two guide pieces respectively secured to the side portions of the bottom surface of the first frame and each guide piece having a guide slot for allowing the projection of a corresponding supporting arm to extend therethrough and to move therealong;

a second folding assembly including a second frame having a rear end pivotally connected to the front end of the first frame;

a first stage drive mechanism mounted on the slide base and operated to drive the supporting arms to slide relative to the slide frame and to make the projections of the supporting arms move along the guide slots of the guide pieces so that the first frame is pivoted relative to the slide base; and

a second stage drive mechanism mounted on the first frame and operated to drive the second frame to pivot relative to the first frame.

2. The foldable leg rest as claimed in claim 1, wherein

the slide base includes

a driven board having its opposite ends respectively secured to rear portions of the supporting arms;

and

a first mounting board having its opposite ends respectively secured to rear portions of the slide frame; and

the first stage drive mechanism includes

a first stage DC motor secured to the first mounting board of the slide base;

a first stage threaded rod driven by the first stage DC motor through a first stage gearing; and

a first stage nut screwed onto the first stage threaded rod and secured to the driven board of the slide base so that the first stage nut is longitudinally movable along the threaded rod.

3. The foldable leg rest as claimed in claim 2, wherein the second stage drive mechanism includes

a second stage DC motor secured to a rear portion of the first frame;

and

two second stage driving rods and two second stage gearings driven by the second stage DC motor.

4. The foldable leg rest as claimed in claim 3, wherein

the first stage gearing has

a first stage pivot shaft driven by the DC motor and having a gear formed on one end thereof;

a first stage first gear meshing with the gear of the pivot shaft; and

a first stage second gear coaxially mounted on the first stage first gear; and

the first stage threaded rod has a gear formed on one end thereof and meshing with the first stage second gear.

5. The foldable leg rest as claimed in claim 4, wherein

the first frame has

a front wall having two sides;

and

two bores respectively formed through the sides of the front wall of the first frame;

the first folding assembly includes

two limit blocks respectively secured to the side portions of the bottom surface of the first frame and each limit block having a hole, the holes of the two limit blocks respectively aligning with the bores of the front wall of the first frame; and

two insertion rods respectively movably inserted in the holes of the limit blocks;

the second frame has

a rear wall having two sides; and

two bores respectively formed through the sides of the rear wall of the second frame and respectively aligning with the bores of the first frame; and

wherein the foldable leg rest further comprises a third stage drive mechanism mounted on the first frame and operated to drive the insertion rods to move in the holes of the limit blocks and to pass through the bores of the first frame and the bores of the second frame so that front ends and rear ends of the insertion rods are respectively disposed in the first frame and the second frame.

6. The foldable leg rest as claimed in claim 5, wherein the third stage drive mechanism includes

a third stage DC motor secured to a middle portion of the first frame;

a third stage threaded rod driven by the third stage DC motor and having a front end rotatably mounted on the front wall of the first frame;

a third stage nut screwed onto the third stage threaded rod and being longitudinally movable thereon; and

a wing having;

a central portion secured to the third stage nut; and

opposite ends respectively secured to the insertion rods.

7. The foldable leg rest as claimed in claim 6, wherein

the first folding assembly includes a second front contact switch and a second rear contact switch respectively secured to front and rear portions of one of the limit blocks;

and

the wing of the third stage drive mechanism has

a bottom surface; and

a contacting rod extending from one side of the bottom surface of the wing and being contactable with the second front or rear contact switch.

8. The foldable leg rest as claimed in claim 4, wherein

each second stage driving rod has a worm formed on one end thereof;

the second stage gearings are each respectively mounted between one side of the first frame and one side of the second frame, and each second stage gearing has a housing secured to the first frame and receiving;

a worm gear meshing with the worm of a corresponding second stage driving rod;

a second stage first gear coaxially mounted on the worm gear; and

a second stage second gear meshing with the second stage first gear; and

each second stage gearing further has

a second stage third gear meshing with the second stage second gear;

a second stage pivot shaft coaxially and securely mounted through the second stage third gear; and

a connecting element secured to the second stage pivot shaft and having a connecting piece extending therefrom and secured to a corresponding side of the second frame.

9. The foldable leg rest as claimed in claim 8, wherein

the first frame has

a front wall having two sides;

and

two bores respectively formed through the sides of the front wall of the first frame;

the first folding assembly includes

two limit blocks respectively secured to the side portions of the bottom surface of the first frame and each limit block having a hole, the holes of the two limit blocks respectively aligning with the bores of the front wall of the first frame; and

two insertion rods respectively movably inserted in the holes of the limit blocks;

the second frame has

a rear wall having two sides; and

two bores respectively formed through the sides of the rear wall of the second frame and respectively aligning with the bores of the first frame; and

wherein the foldable leg rest further comprises a third stage drive mechanism mounted on the first frame and operated to drive the insertion rods to move in the holes of the limit blocks and to pass through the bores of the first frame and the bores of the second frame so that front ends and rear ends of the insertion rods are respectively disposed in the first frame and the second frame.

10. The foldable leg rest as claimed in claim 9, wherein the third stage drive mechanism includes

a third stage DC motor secured to a middle portion of the first frame;

a third stage threaded rod driven by the third stage DC motor and having a front end rotatably mounted on the front wall of the first frame;

a third stage nut screwed onto the third stage threaded rod and being longitudinally movable thereon; and

a wing having;

a central portion secured to the third stage nut; and

opposite ends respectively secured to the insertion rods.

11. The foldable leg rest as claimed in claim 10, wherein

the first folding assembly includes a second front contact switch and a second rear contact switch respectively secured to front and rear portions of one of the limit blocks;

and

the wing of the third stage drive mechanism has

a bottom surface; and

a contacting rod extending from one side of the bottom surface of the wing and being contactable with the second front or rear contact switch.

12. The foldable leg rest as claimed in claim 11 further comprising a mounting bracket and a fourth stage drive mechanism, wherein

the mounting bracket includes

a mounting frame having two sides;

and

two tracks respectively secured to the two sides of the mounting frame;

the slide base includes two first slide blocks respectively secured to the sides of the slide frame and respectively slidably engaging the tracks of the mounting bracket; and

the fourth stage drive mechanism is mounted on the slide base and operated to drive the slide base to move relative to the mounting bracket.

13. The foldable leg rest as claimed in claim 12, wherein the fourth stage drive mechanism includes

a fourth stage DC motor secured to the slide frame of the slide base;

two fourth stage threaded rods driven by the fourth stage DC motor; and

two fourth stage nuts respectively screwed onto the fourth stage threaded rods and respectively secured to the tracks of the mounting bracket so that the fourth stage threaded rods are longitudinally movable relative to the fourth stage nuts.

14. The foldable leg rest as claimed in claim 8, wherein

the first folding assembly includes two first contact switches respectively secured to the sides of the first frame;

and

each second stage gearing has a contacting element secured to the second stage pivot shaft and having a contacting projection extending therefrom and being contactable with a corresponding first contact switch.

15. The foldable leg rest as claimed in claim 14, wherein

the first frame has

a front wall having two sides;

and

two bores respectively formed through the sides of the front wall of the first frame;

the first folding assembly includes

two limit blocks respectively secured to the side portions of the bottom surface of the first frame and each limit block having a hole, the holes of the two limit blocks respectively aligning with the bores of the front wall of the first frame; and

two insertion rods respectively movably inserted in the holes of the limit blocks;

the second frame has

a rear wall having two sides; and

two bores respectively formed through the sides of the rear wall of the second frame and respectively aligning with the bores of the first frame; and

wherein the foldable leg rest further comprises a third stage drive mechanism mounted on the first frame and operated to drive the insertion rods to move in the holes of the limit blocks and to pass through the bores of the first frame and the bores of the second frame so that front ends and rear ends of the insertion rods are respectively disposed in the first frame and the second frame.

16. The foldable leg rest as claimed in claim 15, wherein the third stage drive mechanism includes

a third stage DC motor secured to a middle portion of the first frame;

a third stage threaded rod driven by the third stage DC motor and having a front end rotatably mounted on the front wall of the first frame;

a third stage nut screwed onto the third stage threaded rod and being longitudinally movable thereon; and

a wing having;

a central portion secured to the third stage nut; and

opposite ends respectively secured to the insertion rods.

17. The foldable leg rest as claimed in claim 16, wherein

the first folding assembly includes a second front contact switch and a second rear contact switch respectively secured to front and rear portions of one of the limit blocks;

and

the wing of the third stage drive mechanism has

a bottom surface; and

a contacting rod extending from one side of the bottom surface of the wing and being contactable with the second front or rear contact switch.

18. The foldable leg rest as claimed in claim 17 further comprising a mounting bracket and a fourth stage drive mechanism, wherein

the mounting bracket includes

a mounting frame having two sides;

and

two tracks respectively secured to the two sides of the mounting frame;

the slide base includes two first slide blocks respectively secured to the sides of the slide frame and respectively slidably engaging the tracks of the mounting bracket; and

the fourth stage drive mechanism is mounted on the slide base and operated to drive the slide base to move relative to the mounting bracket.

19. The foldable leg rest as claimed in claim 18, wherein the fourth stage drive mechanism includes

a fourth stage DC motor secured to the slide frame of the slide base;

two fourth stage threaded rods driven by the fourth stage DC motor; and

two fourth stage nuts respectively screwed onto the fourth stage threaded rods and respectively secured to the tracks of the mounting bracket so that the fourth stage threaded rods are longitudinally movable relative to the fourth stage nuts.

20. The foldable leg rest as claimed in claim 1, wherein the second stage drive mechanism includes

a second stage DC motor secured to a rear portion of the first frame;

and

two second stage driving rods and two second stage gearings driven by the second stage DC motor.