Patent Application
20070095641
The present invention is generally related to safety switches. More particularly, the present invention is related to locking mechanisms for safety switches. The invention is also related to use of locking holes on the axis of cam pins to lock safety switches.
Industrial limit switches, such as global limit switches, safety interlocks, safety solenoid interlocks and cable pull limit switches, are used in a wide variety of industrial applications. Limit switches contain switches that are manufactured to suit the particular application.
U.S. Pat. No. 5,703,339 issue to Rapp et al describes a modern safety switch. The safety switch described by Rapp et al uses a key which, when inserted into and removed from a key channel, forcibly rotates a cam plate and thereby switches the position of the switch.
The prior safety switch further has an interlocking device for the cam plate which is disposed adjacent the latter, and can be forcibly released by the key when it is introduced into the key channel and has at least one locking member which can be displaced in translation and, in its locked position, engages in an interlocking manner with a housing disposed adjacent the cam plate. The locking member can be displaced into the released position by the key by means of an actuating which is moveable together with the locking member and is integral therewith. The part of the actuating member which projects into the key channel in the locked position is connected to the locking member by means of a material section which is laterally guided past the axis of rotation.
Despite interlocking in the prior art, it has been determined that more effective locking associated with safety switches is required where it is desirable that the locking mechanism prevent a key from being extracted outside of switch.
The following summary is provided to facilitate an understanding of some of the innovative features unique to the embodiments disclosed and is not intended to be a full description. A full appreciation of the various aspects of the embodiments can be gained by taking the entire specification, claims, drawings, and abstract as a whole.
It is one feature of this invention to provide a configurable switch that can be configured and locked.
It is another object of this invention to provide a configurable switch that contains a configurable locking plunger accommodating multiple moveable arrangements.
In accordance with features of the present invention, an indexing wheel mounted in the head assembly of a safety switch has an axis of rotation extending at right angles to the longitudinal axis of the plunger, and against whose lateral surface the plunger bears. A key channel in the head assembly is adapted for receiving a key and into which the indexing wheel projects. A key, upon being inserted into and upon being withdrawn from the key channel, positively rotates a cam plate about its axis of rotation and in so doing switches over the switch. The switch and key is maintained in locked status by action of the locking hole on the cam pin and by action of the plunger when a key is inserted into the head assembly where the plunger becomes inserted in the locking hole of the indexing wheel and/or the flank on the cam pin after rotation by the key causing the key and switch to become locked.
The accompanying figures, in which like reference numerals refer to identical or functionally-similar elements throughout the separate views and which are incorporated in and form a part of the specification, further illustrate the embodiments and, together with the detailed description, serve to explain the embodiments disclosed herein.
The particular values and configurations discussed in these non-limiting examples can be varied and are cited merely to illustrate at least one embodiment and are not intended to limit the scope thereof.
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During use, a key, upon being inserted in and upon being withdrawn from the key channel, positively rotates the indexing wheel about its axis of rotation and in so doing switches over the switch. The switch and key is maintained in locked status by action of the locking hole on the cam pin and by action of the plunger when a key is inserted into the head assembly where the plunger becomes inserted in the locking hole of the indexing wheel and the flank on the cam pin after rotation by the key causing the key to become locked and wherein removal of the key disengages the switch. Locking prevents the key from being extracted outside of switch until the plunger is released from its position within the indexing wheel. A self-closed locked device, arranged next to the cam plate and capable of being positively released by means of the key upon insertion into the key channel, for the cam plate, having at least one locking member which can be displaced in a translatory fashion and which engages in a self-closed fashion in its locked position with a receptacle arranged next to the cam plate and can be displaced by the key into the release position.
An actuating member constructed in one piece with the locking member and projects into the key channel in the locked position, wherein the part of the actuating member which projects into the key channel in the locked position is connected to the locking member via a material part guided laterally past the axis of rotation. The actuating member can be formed by a sliding member which lies in a plane parallel to the cam plate and is provided with a cutout for passage of the axis of rotation. Both the cam plate as well as the actuating member can be formed from plastic.
It will be appreciated that variations of the above-disclosed and other features and functions, or alternatives thereof, may be desirably combined into many other different systems or applications. Also that various presently unforeseen or unanticipated alternatives, modifications, variations or improvements therein may be subsequently made by those skilled in the art which are also intended to be encompassed by the following claims.
