| 摘要 |
The access assembly, for use with a manhole, grating, ventilation cover assembly etc., comprises a frame 11 that defines an aperture within which one or more seatings are located for receiving one or more cover plates 18. A movable shaft 12a is located on one or more supports and includes one or more shaft formations 28 designed to engage cover and/or frame formations 29 when the shaft is in a first position so as to retain at least a first cover plate relative to the frame and to disengage the cover and/or frame formations when the shaft is in a second position so as to permit removal of at least a first cover plate from the frame. The shaft is supported on journal bearings 22 that extend though opposite walls of the frame so as to be rotatable relative to the frame between first and second positions. Alternatively the shaft may move longitudinally between first and second positions. The shaft formations preferably comprise one or more hooks or recesses with the other of the hooks or recesses being located on the cover and/or frame formations such that the formations are mutually engageable when the shaft is in the first position. One end of the shaft preferably protrudes externally of the wall of the frame and includes an actuator for effecting movement of the shaft which is located in a housing secured to the assembly and adapted to enable the shaft to be locked in at least the first position. The assembly may include more than one shaft. |
