Slide rail assembly

1. A slide rail assembly comprising:

an inner rail;

a middle rail slidably coupled to the inner rail; and

an outer rail slidably coupled to the middle rail; wherein:

the inner rail comprises a first body and a latching member, the latching member extending from the first body toward the middle rail;

the middle rail comprises a second body and a locking device, the locking device fixedly coupled to the second body; and

the locking device defines a latching hole configured to receive the latching member so that the middle rail moves together with the inner rail relative to the outer rail to extend to a designated position and length of the slide rail assembly;

the locking device comprises a locking head; and

the outer rail defines a locking hole configured to receive a portion of the locking head passing through the second body to limit a movement of the middle rail and to remove the latching member from the latching hole.

2. The slide rail assembly of claim 1 , wherein:

the second body comprises a first surface and a second surface;

the first surface and the second surface of the second body are opposite surfaces of the second body;

the first surface of the second body faces the inner rail;

the second surface of the second body faces the outer rail;

the second body defines a through hole passing through the first surface and the second surface;

the locking device is fixedly coupled to the first surface of the second body; and

the locking hole is configured to receive the portion of the locking head passing through the through hole.

3. The slide rail assembly of claim 2 , wherein:

the locking device is made of an elastic material;

a first end portion of the locking device is fixedly coupled to the second body;

the locking head is located on a second end portion of the locking device; and

the locking head resisting against the outer rail deforms the second end portion of the locking device until the locking head is received in the locking hole.

4. The slide rail assembly of claim 1 , wherein:

the locking device is made of an elastic material;

the inner rail further comprises a hook;

the locking device further comprises a base plate and a locking member;

a first end of the base plate is fixedly coupled to the second body;

the locking head is located on a second end of the base plate;

the locking member extends from a side of the base plate in a direction away from the base plate;

the locking head resisting against the outer rail deforms the second end of the base plate until the locking head is received in the locking hole; and

the locking member is configured to engage with the hook to remove the locking head from the locking hole.

5. The slide rail assembly of claim 4 , wherein:

the base plate defines the latching hole between the first end and the locking head of the base plate.

6. The slide rail assembly of claim 4 , wherein:

the first body defines a receiving hole;

the latching member extends from a first side of the receiving hole toward the middle rail;

the hook extends from a second side of the receiving hole toward the first side; and

the second side is opposite to the first side.

7. The slide rail assembly of claim 6 , wherein:

the receiving hole comprises a first hole portion and a second hole portion in communication with the first hole portion;

the latching member is located in the first hole portion;

the hook is located in the second hole portion; and

an edge of the first body on the first side of the second hole portion is opposite an edge of the first body on the second side of the second hole portion.

8. The slide rail assembly of claim 4 , wherein:

the hook comprises a perpendicular plate and a parallel plate;

the perpendicular plate extends from the first body toward the middle rail; and

the parallel plate extends from the perpendicular plate toward the latching member.

9. The slide rail assembly of claim 8 , wherein:

the parallel plate comprises a first surface and a second surface;

the first surface and the second surface of the parallel plate are opposite surfaces of the parallel plate;

an end of the parallel plate adjacent to the latching member forms an inclined surface between the first surface and the second surface of the parallel plate;

a side of the locking member adjacent to the locking head comprises an inclined plate extending, away from the second body; and

the inclined plate is configured to engage with the inclined surface to guide the locking member onto the parallel plate.