Apparatus for fixing pressure vessel

1. An apparatus for fixing pressure vessels, which fixes the pressure vessels to a subject, the apparatus comprising:

a frame part disposed to be separable from the subject and configured to support the pressure vessels; and

a foothold disposed on the frame part,

wherein the frame part comprises:

a first frame member; and

a second frame member disposed to be movable via a connector between a first position at which the second frame member is stacked on an upper portion of the first frame member and a second position at which the second frame member is disposed on a same layer as the first frame member, and

wherein the pressure vessels are respectively disposed on the first and second frame members, and the foothold is disposed on the second frame member.

2. The apparatus of claim 1 , wherein the second frame member is disposed at a same height as the first frame member at the second position.

3. The apparatus of claim 1 , comprising:

wherein said connector is a hinge part configured to connect the first and second frame members to each other so that the first and second frame members are rotatable with respect to each other,

wherein the second frame member rotates about the hinge part from the first position to the second position.

4. The apparatus of claim 1 , comprising:

a locking part configured to selectively lock the second frame member to the first frame member when the second frame member is positioned at the first position.

5. The apparatus of claim 4 , wherein the locking part comprises:

a locking pin disposed on the second frame member; and

a locking module disposed on the first frame member and configured to selectively lock the locking pin.

6. The apparatus of claim 5 , wherein the locking module comprises:

a first locking member rotatably disposed on the first frame member and having a first locking protrusion disposed at one end thereof;

a second locking member rotatably disposed on the first frame member so as to intersect the first locking member and having a second locking protrusion disposed at one end thereof such that the first and second locking protrusions collectively define a locking hole for locking the locking pin; and

an elastic member configured to elastically support rotations of the first and second locking members relative to the first frame member.

7. The apparatus of claim 6 , comprising:

a first inclined guide portion included in the first locking protrusion and configured to guide the locking pin to the locking hole; and

a second inclined guide portion included in the second locking protrusion and configured to guide the locking pin to the locking hole.

8. The apparatus of claim 6 , comprising:

a locking bracket protruding from a bottom surface of the second frame member facing a top surface of the first frame member at the second position,

wherein the locking pin is supported by the locking bracket.

9. The apparatus of claim 8 , wherein the first frame member has an accommodation portion that accommodates the locking bracket therein.

10. The apparatus of claim 9 , comprising:

a base block accommodated in the accommodation portion,

wherein the first and second locking members are rotatably coupled to the base block.

11. The apparatus of claim 10 , wherein the accommodation portion of the first frame member includes a locking groove configured to lock the base block.

12. The apparatus of claim 1 , wherein the frame part further comprises a third frame member disposed at one side of the first frame member such that the third frame member is disposed on the same layer as the first frame member, and a foothold disposed on the third frame member is disposed to have a level difference from the foothold disposed on the second frame member.

13. The apparatus of claim 1 , wherein the subject comprises a construction machine.