Self-setting switch-actuating assembly and method

In a position sensing apparatus, the combination comprising:

• (a) a mounting base;
• (b) a pair of switches mounted in spaced apart relation on said mounting base and in offset relation such that one switch is disposed closer to said mounting base than the other switch so as to define open space above said one switch and below said other switch;
• (c) a pair of self-setting switch-actuating cam members for actuating said switches when placed in predetermined actuating positions relative thereto;
• (d) a rotational motion transmitting shaft rotatably mounted on said mounting base generally between said switches thereon and being connectible to a rotatable device whose rotational movement will cause rotation of said motion transmitting shaft and will stop in response to reaching angularly-displaced limits of such rotational movement;
• and
• (e) means mounting said cam members on said motion transmitting shaft with one cam member above the other cam member such that said one cam member is aligned with only said other switch and open space above said one switch whereas said other cam member is aligned with only said one switch and open space below said other switch, said mounting means for permitting self-setting of each of said cam members relative to said motion transmitting shaft by allowing movement of said cam member along a rotational path toward and away from one of said actuating positions relative to its aligned switch and into and from the open spaces above and below its nonaligned switch in response to corresponding rotation of said motion transmitting shaft and stopping of movement of said cam member in response to reaching its actuating position and relative to continuing rotation of said motion transmitting shaft thereby permitting a predetermined degree of overtravel of said motion transmitting shaft relative to each of said cam members at their respective actuating positions for accomplishing said self-setting of said cam members.

A method of self-setting an assembly for actuating a pair of switches spaced apart on a mounting base, said method comprising the steps of:

• (a) coupling a rotational motion transmitting shaft being rotatably mounted on the mounting base between the switches to a rotatably device whose rotational movement will cause rotation of the shaft and will stop in response to reaching one or the other of a pair of angularly-displaced limits;
• (b) imposing upon each of a pair of cam members mounted one above the other on the motion transmitting shaft an amount of frictional force being sufficient to cause the cam member to move along a rotational path with rotation of the shaft toward and away from an actuating position adjacent one of the switches and also insufficient to prevent relative rotation between the cam member and the shaft for permitting stopping of movement of the cam member relative to continuing rotation of the shaft upon the cam member reaching its actuating position adjacent one of the switches;
• (c) as the shaft is maintained stationary, manually rotating each of the cam members about the shaft to its respective actuating position;
• (d) rotating the rotatable device until it reaches one of its angularly-displaced limits to cause rotation of the motion transmitting shaft and thereby one of the cam elements away from its actuating position and toward the other cam element as the other cam element remains at its actuating position;
• and
• (e) rotating the rotatable device until it reaches the other of its angularly-displaced limits to cause rotation of the motion transmitting shaft and thereby the other of the cam elements away from its actuating position and toward and into alignment with the one cam element as the one cam element remains at its actuating position, such that each of the cam elements are now self-set for actuating its respective one of the switches at said respective actuating positions for sensing the positioning of the rotatable device at either of the opposite limit positions thereof upon rotation of the rotatable device therebetween.