Caster with brake unit and direction unit

1. A caster (A) comprising:

a casing ( 1 ) having a shank ( 11 ) which is radially connected to the casing ( 1 ) and a locking unit ( 12 ) is located at a lower end of the shank ( 11 );

two wheels ( 2 ) connected to two sides of the casing ( 1 ) and a shaft ( 21 ) extending through the two wheels ( 2 ) and the casing ( 1 ), an inner gear ( 22 ) connected to each of the two wheels ( 2 );

a direction unit ( 3 ) located in the casing ( 1 ) and including a first lever ( 31 ) and an opening ( 311 ), the first lever ( 31 ) connecting the direction unit ( 3 ) to the locking unit ( 12 ); and

a brake unit located in the casing ( 1 ) and including a second lever ( 41 ), the second lever ( 41 ) connecting the brake unit to the locking unit ( 12 ) and the inner gears ( 22 ), the second lever ( 41 ) being engaged with the opening ( 311 ) of the first lever ( 31 ) and sharing a common pivot ( 411 ) with the first lever ( 31 ) to respectively brake the caster and control direction of the caster, the brake unit further including a second plate ( 42 ), a second piece ( 43 ), a second spring ( 44 ), a return spring ( 46 ) and a guide plate ( 45 ).

2. The caster as claimed in claim 1 , wherein the locking unit ( 12 ) includes a gear ( 121 ) and a direction plate ( 122 ).

3. The caster as claimed in claim 2 , wherein the direction plate ( 122 ) includes multiple radial recesses ( 123 ).

4. The caster as claimed in claim 1 , wherein the direction unit ( 3 ) includes a first plate ( 32 ), a first piece ( 33 ) and a first spring ( 34 ).

5. The caster as claimed in claim 4 , wherein the first plate ( 32 ) includes a pivot ( 321 ) at a mediate portion thereof and the first plate ( 32 ) is pivotably connected to the casing ( 1 ) by the pivot ( 321 ), the first plate ( 32 ) has one end contacting an extension ( 312 ) on an underside of the first lever ( 31 ), the other end of the first plate ( 32 ) is inserted into a side notch ( 331 ) of the first piece ( 33 ).

6. The caster as claimed in claim 5 , wherein the first piece ( 33 ) is horizontally engaged with a slot ( 13 ) in the casing ( 1 ) and a first protrusion ( 332 ) extends from an underside of the first piece ( 33 ), a first spring ( 34 ) biases the first protrusion ( 332 ).

7. The caster as claimed in claim 6 , wherein the first plate ( 32 ) is a flexible plate.

8. The caster as claimed in claim 6 , wherein the first spring ( 34 ) is a cone-shaped spring.

9. The caster as claimed in claim 1 , wherein the second plate ( 42 ) includes a pivotal point ( 421 ) at a mediate portion thereof and is pivotably connected to the casing ( 1 ) by the pivotal point ( 421 ), the second plate ( 42 ) has one end contacting an underside of the guide plate ( 45 ) and the other end of the second plate ( 42 ) is inserted into a side hole ( 431 ) of the second piece ( 43 ).

10. The caster as claimed in claim 9 , wherein the second piece ( 43 ) is horizontally engaged with a slot ( 13 ) in the casing ( 1 ) and has a second protrusion ( 432 ) extending from one end thereof, the second protrusion ( 432 ) is biased by the second spring ( 44 ).

11. The caster as claimed in claim 10 , wherein the guide plate ( 45 ) includes multiple grooves ( 451 ) and includes a curved surface composed of a high point ( 452 ), a concaved and inclined surface ( 453 ) and a low point ( 454 ), the second lever ( 41 ) has a leg ( 412 ) contacting the curved surface.

12. The caster as claimed in claim 1 , wherein the casing ( 1 ) includes a passage ( 15 ) and the guide plate ( 45 ) is guided within the passage ( 15 ) and the return spring ( 46 ) is located at an underside of the guide plate ( 45 ).

13. The caster as claimed in claim 12 , wherein the passage ( 15 ) has a concavity ( 151 ) and the guide plate ( 45 ) has a reception recess ( 455 ), two ends of the return spring ( 46 ) are engaged with the concavity ( 151 ) and the reception recess ( 455 ).

14. The caster as claimed in claim 1 , wherein a cushion pad ( 14 ) is connected to the casing ( 1 ) and located outside of the locking unit ( 12 ).

15. The caster as claimed in claim 14 , wherein the cushion pad ( 14 ) is connected to a frame ( 141 ) fixed to the casing ( 1 ).

16. A caster comprising:

a casing having a shank radially connected to the casing and a locking unit located at a lower end of the shank;

two wheels respectively connected to two sides of the casing and a shaft extending through the two wheels and the casing, each of the two wheels having an inner gear connected thereto;

a direction unit being located in the casing and including a first lever having an opening therein, the first lever connecting the direction unit to the locking unit, the direction unit further including a first plate, a first piece and a first spring, the first plate including a pivot at a mediate portion thereof and being pivotally connected to the casing by the pivot, the first plate having one end thereof contacting an extension on an underside of the first lever, an other end of the first plate being inserted into a side notch of the first piece; and

a brake unit being located in the casing and including a second lever, the second lever connecting the brake unit to the locking unit and the inner gears, the second lever being engaged with the opening of the first lever and sharing a common pivot with the first lever to respectively brake the caster and control direction of the caster.