Claims
- 1. A generally vertically extending chute terminating at an open end bounded by a frame mounted to a support surface and a chute door having a front surface, side surfaces extending from the front surface and a door pivot at the bottom of the front surface journalled at the frame whereby door opening, assisted by door gravity, results by rotation of the door front surface about the door pivot from a closed position, whereat the front surface is generally adjacent and closes the chute's open end while the side surfaces extend into the chute, to an open position, whereat the front surface is at least 45° displaced from its closed position and the side surfaces are out of the chute, the improvement comprising:a first linkage arrangement adjacent one of the door side surfaces including a door pivot link extending from the door pivot, a pivotable variable length electric actuator link, and a plurality of interconnecting links pivotably connected to the door pivot and actuator link; an electric motor for varying the length of the electric actuator link which causes the chute door to rotate from an open to a closed position; a second linkage arrangement adjacent said one of the door side surfaces resisting door opening and for assisting door closing, the second linkage arrangement including a variable length spring actuator link and an intermediate link pivotably secured to one end of the spring actuator link and the door pivot link, the other end of the spring actuator link being fixed to a front panel for permitting expansion and contraction of the spring actuator link in one direction, the spring actuator link having an increased length when the chute door is opened and a decreased length when the chute door is closed and an air spring controlling the length of the spring actuator link by exerting a force tending to keep the spring actuation link at a decreased length; a manually operated switch for actuating the motor to open and close the chute door; and, an axially retractable lock between the frame and the chute door, a third linkage mechanism including a pivotable lock link for moving the lock between a locked and an unlocked condition, an intermediate pivotable door lock link pivotably connected to the lock link and the interconnecting link of the first linkage arrangement and the pivotable connection between the door pivot link and the interconnecting link in the first linkage arrangement being slotted whereby a lost motion connection assures unlocking the lock prior to door opening and locking the lock after door closing.
- 2. A door closure for a chute door which without said closure pivotably rotates by gravity from a closed to an open position and which has an axially movable lock, the chute door closure comprising:an electric motor; a pivoted, linearly variable actuator link having a variable length determined by operation of the motor, a rotatable door pivot link for rotating the chute door; a plurality of interconnecting links pivotably connecting the door pivot link with the linear actuator link, one end of one of said interconnecting links that forms the pivotal connection having a slotted connection whereby movement of the linear actuator link in one direction rotates the door pivot link after the interconnecting links have moved the distance of the slotted connection; an intermediate lock link pinned at one end thereof to the interconnecting links; a rotatable latch crank pivotably pinned at one end thereof to the intermediate lock link, the latch crank having a lock releasing free end and a fixed pivot between its free end and its pinned end about which the latch crank rotates, whereby the lock releasing free end rotates upon actuation of the linear actuator in one direction before the door pivot link is caused to rotate; and, a switch for actuation of the electric motor.
- 3. The door closure of claim 2, further including an air spring, a variable length spring actuator link extending from the air spring and an intermediate link pivotably connected at one of its ends to the spring actuator link and at its other end to the door pivot link whereby the air spring assists movement of the linear actuator link when the pivot door link rotates in one direction.
- 4. The door closure of claim 2, further including open and close limit switches actuated by movement of the intermediate link and a time actuation circuit causing the electric motor to cease operating at a set time after switch actuation.
Parent Case Info
This is a continuation of application Ser. No. 09/476,552 filed Jan. 3, 2000, now U.S. Pat. No. 6,186,306, which has claimed priority under 35 U.S.C. § 120 from application Ser. No. 09/081,641 filed May 20, 1998, which issued as U.S. Pat. No. 6,062,368 on May 16, 2000; and application Ser. No. 08/549,264, Oct. 27, 1995 now abandoned, each of which is incorporated herein by reference.
US Referenced Citations (34)
Continuations (3)
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Number |
Date |
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09/476552 |
Jan 2000 |
US |
Child |
09/693162 |
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US |
Parent |
09/081641 |
May 1998 |
US |
Child |
09/476552 |
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Parent |
08/549264 |
Oct 1995 |
US |
Child |
09/081641 |
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