| 摘要 |
The invention relates to a supporting member comprising at least two relatively turnable parts, said two parts accommodating a biassed, helically wound tensile spring fixed at least at two spots, whereby the supporting member comprises several curved or sharply bent parts which can be turned with respect to one another, while in the spring such a torsional tension is produced that the parts will remain in any desired, normal position of use relative to one another under the influence of said torsional stress and the friction prevailing between the relatively turnable parts.
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