摘要 |
A height adjustable mechanism for supporting a work surface for vertical movement relative to a base includes a counterbalance mechanism for providing a force opposing a downward force tending to lower the work surface; a brake mechanism for releasably retaining the work surface in a desired vertical position; a user operated release mechanism for selectively releasing the brake mechanism to permit vertical movement of the work surface; and an interlock mechanism for preventing release of the brake mechanism if the force and the downward force are out of balance by some given extent. In the preferred construction, the interlock mechanism includes an interlock plate supported by the base for pivotal movement between first and second blocking positions when the force is less than and greater than the downward force, respectively, through a neutral position when the force essentially corresponds to the downward force, and the release mechanism engages with the interlock plate when in the blocking positions thereof to prevent release of the brake mechanism by a user.
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