Door interlock for electrical apparatus
AssigneeS&C Electric Company
InventorsEdmund S. Dizon, Joseph P. Moninski, Jr.
Life of this patent
Estimating the term…
Abstract
A door interlock for electrical apparatus, which may include a switch, within an enclosure, permits the door of the enclosure to be opened only if the electrical apparatus is in a predetermined condition, such as switch-closed. Once the switch has been opened, the door may be opened. The interlock prevents the switch from being reclosed as long as the door is open. A latch holds the door closed if the switch is closed, if the door is locked closed by a door lock, or if both conditions obtain. If the switch is opened while the door is locked closed by the door lock, the latch continues to latch the door closed. If the door lock is unlocked while the switch remains closed, the door latch likewise latches the door closed.
Claims14
An improved interlock for electrical apparatus located in a walled enclosure, the interlock being of the type which prevents opening a door of the enclosure if the apparatus is in a first condition and permits opening the door to provide access to the apparatus only if the apparatus is in a second condition, the interlock preventing the apparatus from assuming the first condition when the door is open, wherein the improvement comprises:
- latching means movable between a first position, for latching the closed door against opening, and a second position, for unlatching the closed door for opening;
- cam follower means movable between a first position, for holding the latching means in its first position, and a second position, for holding the latching means in its second position;
- means for biasing the cam follower toward its second position;
- locking means operable from the exterior of the enclosure and movable between a first position, for locking the closed door against opening and for holding the cam follower means in its first position, and a second position, for unlocking the closed door for opening and for freeing the cam follower means for movement to its second position by the biasing means, the closed door being openable only if the locking means and the latching means are both in their second positions;
- control means movable between a first and a second position, the control means being unable to move out of its first position if the apparatus is not in its second condition and being movable to its second position only if the apparatus is in its second condition;
- means for preventing the apparatus from assuming its first condition if the control means is in its second position;
- and
- means interconnecting the control means and the cam follower means for
- (a) holding the control means in its first position when the cam follower means is held in its first position,
- (b) moving the control means to its second position when the cam follower means moves to its second position and the apparatus is in its second condition, and
- (c) preventing the cam follower means from moving to its second position if the control means is unable to move to its second position.
An improved interlock for electrical apparatus located in a walled enclosure, the interlock being of the type which prevents opening a door of the enclosure if the apparatus is in a first condition and permits opening the door to provide access to the apparatus only if the apparatus is in a second condition, the interlock preventing the apparatus from assuming the first condition when the door is open, wherein the improvement comprises:
- locking means on the door and operable from the exterior of the enclosure for movement between a first position, whereat the closed door is locked against opeing, and a second position, whereat the door is unlocked for opening;
- latching means on the enclosure for movement between a first position, whereat the closed door is latched against opening, and a second position, whereat the door is unlatched for opening, the closed door being openable only if the locking means and the latching means are both in their second positions;
- cam follower means on the enclosure for movement between a first position, whereat the latching means is held in the first position, and a second position, whereat the latching means is held in its second position;
- means for biasing the cam follower toward the second position;
- cam means on the locking means for holding the cam follower means in its first position when the locking means is in its first position and for freeing the cam follower means for movement to its second position by the biasing means when the locking means is in its second position;
- movable control means on the apparatus for movement between a first and a second position, the control means being unable to move out of its first position if the apparatus is not in its second condition and being movable to its second position only if the apparatus is in its second condition;
- means for preventing the apparatus from assuming its first condition if the control means is in its second position;
- and
- means interconnecting the control means and the cam follower means for
- (a) holding the control means in its first position when the cam follower means is held in its first position,
- (b) moving the control means to its second position when the cam follower means moves to its second position and the apparatus is in its second condition, and
- (c) preventing the cam follower means from moving to its second position if the control means is unable to move to its second position.
Dependencies are inferred from the claim text.