NZ737936B2 - A safety cabinet and an associated door controlling mechanism - Google Patents

Abstract

Provided is a safety cabinet having at least two doors, a first of said doors being a slave door and a second of said doors being a master door. The cabinet is configured to perform ‘door selection’, which means that when the doors are free to close, the slave door must close first and the master door second. The slave door and the master door each being subject to the action of at least one door closing mechanism (4, 5). A slave cam (6) is operative with the slave door so as to displace a connector member (8) to a first position in response to closure of the slave door, and to displace the connector member (8) to a second position in response to opening of the slave door. A master cam (7) is operative with the master door and includes a locking arrangement to which the connector member (8) is connected. The locking arrangement being configured so as to retain the master door at one of a plurality of possible opening positions when the connector member (8) is in the second position, and to release the master door when the connector member (8) is in the first position. The locking arrangement includes a pivotally mounted rod (20) that is engageable with the master cam, by a meshing of teeth, at one of a plurality of possible engagement positions. The plurality of possible engagement positions corresponds to the plurality of possible opening positions. The door closure mechanism of the present invention functions as not only a door selector, but also as a door stay.

Claims (12)

The claims defining the invention are as follows

1. A safety cabinet having at least two doors, a first of said doors being a slave door and a second of said doors being a master door; the cabinet including the following: the slave door and the master door each being subject to the action of at least one door closing mechanism; a slave cam operative with the slave door so as to displace a connector member to a first position in response to closure of the slave door and so as to displace the connector member to a second position in response to opening of the slave door; and a master cam operative with the master door and including a locking arrangement to which the connector member is connected, the locking arrangement being configured so as to retain the master door at one of a plurality of possible opening positions when the connector member is in the second position and so as to release the master door when the connector member is in the first position, the locking arrangement including a pivotally mounted rod that is engageable with the master cam, by a meshing of teeth, at one of a plurality of possible engagement positions, wherein the plurality of possible engagement positions corresponds to the plurality of possible opening positions.

2. A safety cabinet according to claim 1, wherein the master cam includes a plurality of teeth, each of the plurality of teeth corresponding to one of said plurality of possible engagement positions, and wherein the rod has at least one tooth shaped so as to mesh with the plurality of teeth on the master cam.

3. A safety cabinet according to claim 2, wherein the connector member is connected to the rod so as to position the at least one tooth within a meshing proximity relative to the plurality of teeth on the master cam when the connector member is in the second position and so as to position the at least one tooth outside the meshing proximity relative to the plurality of teeth on the master cam when the connector member is in the first position.

4. A safety cabinet according to claim 1, wherein the rod is resiliently biased towards engagement with the master cam.

5. A safety cabinet according to claim 2, wherein the engagement between the rod and the master cam is configured so as to ratchet the meshing of the teeth in response to opening of the master door.

6. A safety cabinet according to claim 5, wherein the master cam is resiliently biased towards a rotational direction that advances ratcheting of the meshing of teeth.

7. A safety cabinet according to claim 5 or 6, wherein, in use, a line of force results from the meshing of the teeth and wherein a pivot point at which the rod pivots is disposed on the same side of the line of force as the master cam.

8. A safety cabinet according to any one of the preceding claims, wherein the master cam defines a seat shaped so as to releasably receive an element that is mechanically coupled to the master door so as to move in response to movement of the master door, the element being moveable along a first track in which the element is seated within the seat and wherein the element is constrained from being released from the seat by a defined boundary, the element also being moveable along a second track in which the element is remote from the defined boundary and is therefore free to be displaced out of the seat.

9. A safety cabinet according to claim 8, wherein the element is a circular bearing and wherein the seat is an open notch having a curvature substantially matching, or being slightly greater than, a curvature of the circular bearing.

10. A safety cabinet according to claim 8 or 9, wherein the first track corresponds to an opening range of the master door that encompasses said plurality of possible opening positions and wherein the second track corresponds to an opening range of the master door that extends beyond said plurality of possible opening positions.

11. A safety cabinet according to claim 4, wherein the slave cam is pivotally mounted adjacent to the slave door, wherein the connector member is pivotally connected at a first end to the slave cam and at a second end to the rod, wherein the slave door, or a projection disposed on the slave door, displaces the slave cam in response to closing of the slave door to thereby displace the connector member to the first position and wherein opening of the slave door provides clearance for the slave cam to move, thereby allowing movement of the connector member to the second position due to the resilient biasing of the rod.

12. A door controlling mechanism for a safety cabinet having at least two doors, the first of said doors being a slave door and the second of said doors being a master door, wherein the slave door and the master door are each subject to the action of at least one door closing mechanism; the door controlling mechanism including the following: a slave cam operative with the slave door so as to displace a connector member to a first position in response to closure of the slave door and so as to displace the connector member to a second position in response to opening of the slave door; and a master cam operative with the master door and including a locking arrangement to which the connector member is connected, the locking arrangement being configured so as to retain the master door at one of a plurality of possible opening positions when the connector member is in the second position and so as to release the master door when the connector member is in the first position, the locking arrangement including a pivotally mounted rod that is engageable with the master cam, by a meshing of teeth, at one of a plurality of possible engagement positions, wherein the plurality of possible engagement positions corresponds to the plurality of possible opening positions. 1 / 27