Switch Assembly Feeler

Abstract

The present invention provides a feeler device for a switch assembly which has a nonhelical workpiece-engaging end portion and a switch-engaging portion with a helically formed spring portion intermediate the work-engaging portion and the switch-engaging portion.

Description

BACKGROUND OF THE INVENTION

This invention relates generally to feelers for switch assemblies and more particularly to feelers for engaging moving work, especially paper sheets, on a path of travel and operating a microswitch or the like responsive to movement of the work. For example, the switch finds application in certain copying machines wherein various operations must be actuated at predetermined positions of paper moving therethrough.

One of the principal prior art configurations of such feelers is merely an elongated flexible wire disposed in the path of travel. This type of feeler has many advantages in that it is flexible to resist distortion over a limited range of flexure. However, there are certain disadvantages to this type of prior art feeler. Principal among these disadvantages is the susceptibility of the feeler to become bent or distorted due to accidental bending beyond a limited range. For example during cleaning of a machine, a switch may be accidentally snagged and bent to such a degree that it is distorted to the bent condition. If such distortion is not recognized the timing of the operation of the machine may be affected. Thus the ability of this type of feeler to be distorted can cause detrimental results.

In order to overcome the propensity of these prior art switches to accidental distortion by bending, there has been proposed the use of a coil spring in place of the straight resilient wire. The use of such a spring does in fact eliminate or at least minimize the detrimental aspect of the straight wire feeler in that the spring can be severely distorted and still return to its original preset position. However, the use of a spring per se has presented additional problems and drawbacks not found in the straight wire-type feeler. One of these problems is that the edge of the paper, as it comes into contact with the coils of a spring may be caught. This impedes the smooth flow of the paper often with very serious jamming.

Another limitation of the spring feeler device is that it is difficult to make minor adjustments to the spring for exact alignment of the spring in the path because of its great inherent resistance to distortion by bending. Such adjustment can be accomplished only by deforming the spring, which deformation detracts from the inherently beneficial spring characteristics and in fact may defeat the purpose of the spring by allowing this area to deform upon accidental contact.

The present invention incorporates the beneficial characteristics of both the straight rod and coil spring feelers and eliminates the detrimental aspects of both.

DESCRIPTION OF THE DRAWING

The single FIGURE shows a feeler device for actuating a switch mechanism according to this invention and depicts the feeler and switch device schematically installed on a machine which has a path of travel for a workpiece, and shows a distorted reverse bend in phantom.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to the drawing, a switch assembly designated generally as 10 is shown incorporating feeler arm 12 of this invention. The feeler arm 12 is formed of a resilient wire which has a work-engaging portion 14 at one end thereof and a switch-engaging portion 16 at the other end thereof. The wire is wound with helical spring convolutions 18 intermediate the end portions 14 and 16. The switch-engaging portion 16 is connected to actuator 20 of the switch assembly 10. The switch assembly 10 is shown positioned so that the work-engaging portion 14 of the feeler arm 12 is disposed in the path of travel of an article which is to actuate the switch. In the drawing, the path of travel is designated by the broken line P and article A representing a piece of paper traveling along the path of travel P in the direction indicated by the arrow. As the article A moves along the path of travel, the end thereof strikes the work-engaging portion 14 of the feeler arm. Since the work-engaging portion is free of helical convolutions there is no danger that the article could become caught in such convolutions. The article will push the feeler arm to the left as seen in the FIGURE, actuating the switch for whatever purpose is desired. The article A will pass over the end of the feeler arm as it continues on its path of travel. As can be seen in the drawing, the end of the switch-engaging portion 14 is bent to a loop as shown at 22. This is to provide a smooth surface free of jagged edges over which the article will pass so that the switch will not rip the article nor catch or impede the progress of the article as it passes thereover. Once the article has passed over the feeler arm 12, the arm will return to its upright position due to a return spring connected to actuator 20 contained in the switch assembly 10.

If the article A were to become jammed in the path P and become crumpled or bunched in the area of the feeler 12, the normal practice to remove the crumpled article would be to pull it backwards in the opposite direction of normal path travel. The phantom outline of feeler 12 illustrates how the spring convolutions 18 will yield as the article is removed, and once removed will return to their normal position without permanent distortion.

This construction of the feeler arm combines the advantages of the prior art feeler devices without incorporating their disadvantages. The helical spring convolutions 18 allow the feeler 12 to be bent to a very substantial degree and still return to its original position. The amount of such bending is far greater than can be tolerated by a straight rod (i.e., nonhelical rod) of the same size and material. Thus distortion of the feeler arm due to unintended bending is minimized. Hence, the advantages of the helical spring configuration for a feeler arm are retained.

The work-engaging portion 14 and the switch-engaging portion 16 are formed of straight (i.e., nonhelical) wire. Thus if it is desired to adjust the position of the feeler this can be done by intentionally bending either of these straight portions 14 or 16 to provide for minor adjustments of the position of the work-engaging portion 14 of the path of travel. The spring convolutions 18 need not be distorted so they can function as a spring. Also as indicated above, the work-engaging portion 14 does not have a helically coil configuration to catch and impede the progress of the article. Thus the desirable features of a straight wire feeler arm are retained in that minor position adjustments can be made by bending in the nonhelical formed sections and there is no danger of helices catching and impeding the progress of the article.

Claims

What we claim is:

1. In a device wherein an article is conveyed along a predetermined path of travel, the combination of a feeler lever having adjustable means and a switch mechanism comprising:

a wire having first and second ends;

said wire having a work-engaging portion adjacent said first end positioned to intersect said path of travel, said work-engaging portion having means to prevent article obstruction at the location of engagement of the work-engaging portion with the article, and,

said second end connected to said switch mechanism; said switch mechanism being actuatable by the angular movement of the lever as a unit,

a helically coiled portion intermediate said work-engaging portion and said second end, both said work-engaging portion and a portion adjacent said second end being free of helical convolutions and having accessible separated straight portions being of sufficient size and substantially equal length and cross section, whereby adjustment of position of said feeler lever can be accomplished by bending either or both of the separated straight portions.