| 摘要 |
Hydraulic door closer apparatus includes means for counter-balancing the bias of a return spring, to either assist in opening the door by reducing the force needed to open, or, in an alternative embodiment and mode of operation, to open the door by over-balancing the bias of the return spring. In the latter mode, a remotely manually operable switch, such as, for example, a so-called palm button, may initiate opening the door.
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