| 摘要 |
An apparatus comprises a frame assembly comprising a first side member and a second side member, and at least one spreader member. The spreader member comprises a first triangular member, a coupling member and a second triangular member. The first and second triangular members each comprise a vertex end and a base end. The coupling member comprises first and second end portions. The first triangle member is coupled to the first side member along the base end of the first triangular member. The second triangle member is coupled to the second side member along the base end of the second triangular member. The vertex end of the first triangular member and the vertex end of the second triangular member are respectively coupled to the first and second end portions of the coupling member.
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