US 5,520,424 AGranted

Tamper-proof door switch and latch device

AssigneeU.S. Controls Copr.

InventorsKenyon A. Hapke, Spencer C. Schantz

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Abstract

In a door latching and switch contact controlling device, an actuator having first and second radially extending angularly spaced apart members is mounted on a common shaft in a housing with a latching member for the member and actuator to rotate together. A striker fastened to a door strikes the first radially extending member when the door closes to turn the actuator so the second member rotates into an opening in the striker to thereby conceal the first member. An electroresponsive device positions a latching element into the path of a stop on the latching member when the device is energized, thereby preventing the actuator from turning reversely if an attempt is made to open the door. The device locks the door if it is closed, if the actuator is rotated by the striker and the electroresponsive device is energized, whereupon a pair of contacts are compelled to make contact to complete a circuit for signalling a controller that it can initiate existence of a hazardous condition that is prevented from being accessed by the locked door.

Claims27

Dependent claims

A switch and latching device adapted for latching a closure member, such as the lid, cover or door of an enclosure, including:

a housing,
an actuator mounted in the housing for rotating about an axis in forward and reverse directions, the actuator having first and second members extending radially outwardly of the axis and angularly spaced apart about the axis,
a striker member for being mounted to the closure member and constructed and arranged for striking the first radially extending member and entering the space between the radially extending members of the actuator when the closure member closes to thereby rotate the actuator in the forward direction,
a latching member coupled to said actuator for rotating in said housing in forward and reverse directions through angles corresponding to the angles of rotation of the actuator caused by the striker member acting on the actuator,
return spring means for biasing said latching member and actuator toward rotating in said reverse direction in opposition to the force of said striker that causes the latching member and actuator to rotate in the forward direction,
a latching element and a restoring spring urging said element into an inactive position and the element is mounted for being moved into an active position wherein it can interfere with the latching member rotating in the reverse direction after having been rotated in the forward direction by the striker member when the closure member is closed, and
a force generator that responds to a signal by moving the latching element into the active position for interfering with the latching member to thereby keep the closure member latched, discontinuance of the signal allowing said restoring spring to restore said latching element to the inactive position so the closure member can be opened.

4 more elements

A device for automatically locking a door on an enclosure comprising:

a striker member mounted to the door and constructed and arranged for passing through an opening with which the door cooperates when the door is closing,
a housing for mounting in the enclosure, the housing having an aperture for the striker member to enter the housing when the door is closed,
an actuator body in the housing mounted for rotating about an axis in forward and reverse directions, the actuator body having an open slot extending generally radially-outwardly of the axis for the striker member to enter and rotate the actuator body in said forward direction when the door closes,
a cam member coupled to said actuator body for rotating coaxially in the housing in forward and reverse directions correspondingly with the actuator body, the cam member having a peripheral surface constituting a segment of a circle that terminates in the circumferential direction to thereby define a radially extending stop element,
a restoring spring operative to urge the actuator body in said reverse direction to an initial rotational position wherein the opening of said slot in the body is presented toward the opening of the door for said striker member to enter the slot and rotate the actuator and said cam member in said forward direction when the door is closing,
an electromagnet assembly including a coil and a core that is magnetized when current flows in the coil,
a magnetically attractable latching element mounted for pivoting proximate to said core and a spring arranged for urging said latching element in a direction away from the core and when current flows through said coil the resulting magnetic force attracts said latching element member toward the core and into a cam member interfering position, the latching element having one end portion that extends over said peripheral surface of the cam member and when the cam member is rotated in said first direction and the said stop element on the cam member rotates past said end portion of the latching element if the coil is energized the latching element moves into interfering position relative to the stop element, whereby said cam member and actuator cannot rotate in the reverse direction under the influence of said restoring spring so the door cannot be opened.

4 more elements

Dependencies are inferred from the claim text.

Facts

Application: 08/380,308Filed 30 Jan 1995
Granted: 28 May 1996
Term ends: Not estimatedThe source records don’t support an estimate.

Classification21 codes

E05B 47/0607
Controlling mechanically-operated bolts by electro-magnetically-operated detents: the detent moving pivotally or rotatively
D06F 37/42
Details specific to washing machines covered by groups D06F21/00 - D06F25/00: safety arrangements, e.g. for stopping rotation of the receptacle…
E05B 47/0002
With electric actuators; Constructional features thereof: with electromagnets
E05C 3/24
The bolt being spring controlled: in the form of a bifurcated member