US 3426165 A
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Description (OCR text may contain errors)
Feb. 4,1969 N. v. BEAMAN ELECTRIC SWITCH OPERATING AND MOUNTING MEANS Filed Dec. 6, 1966 CONVEVQQ I $7 co/vVEs ae 41 J95 INVENTOR. A/oe/maw 554/174 BY United States Patent 4 Claims The present invention relates generally to operating means for an electric switch, and more particularly to an electric switch actuator operated by relative movement of the surface of an object being sensed which inhibits movement of the actuator by false surfaces which it encounters. The invention includes switch mounting means to reference the actuator relative to the object surface to be sensed.
While the electric switch actuator and mounting are disclosed and described herein in connection with the spraying of an oil film in the cavity in a baking pan or the like, it is to be understood that the present invention is not limited thereto but will have other uses where electric switch operation is desired by a positioned or indexed element, device, or part which causes switch operation to initiated a control function. In the specific environment in which the electric switch actuator and mounting of the present invention has been illustrated, the positioning or indexing of a baking pan cavity relative to a spray device operates an electric switch to actuate the spray device to coat the pan cavity with an oil film.
Baking pans are customarily made with groups of cavities, as illustrated, and are provided with peripheral braces, such as rolled edges, and with strengthening ribs and the like which may extend down to the same plane as the cavity bottom which is used to sense the cavitys position. Such strengthening ribs, braces, or the like would, in ordinary limit switch operators, such as simple rollers or brushes, cause a switch operation for each surface thus extending to the cavity bottom level, thereby effecting undesired and improper operation of the cavity spraying device.
According to the present invention, a switch actuator, specifically shown as a pivoted arm, is moved by a lobed rotor like a star wheel mounted thereon and free to rotate relative thereto. The lobed rotor or star wheel is constructed to rotate freely about the braces, strengthening ribs, rolled edges, etc., of the baking pans'which it receives in the depressions between its lobes so that no movement of the switch actuator is caused by passage of these parts therepast. However, when a flat surface of sufficient extent engages the rotor so that two lobes thereof are engaged by that fiat surface at the same time, as by the bottom surface beneath a pan cavity, the actuator of the switch will be moved downwardly to effect a switch operation. Ordinarily, the two engaged lobes slide over the smooth bottom surface defining the pan cavity, but if dents or other surface irregularities should cause the rotor or star wheel to rotate, this causes no problem since further downward movement or overtravel of the switch actuator is provided for.
Since the baking pans and other items which are to be sensed by the electric switch according to the present invention may become distorted by warping, bending, and
the like, the distortion may become so great as to prevent effective operation of the electric switch if it is fixably mounted. That is, the ordinarily operating surface may be so far removed from the switch that it does not cause sufficient movement of the actuator to operate the switch. To take care of this, the switch is desirably resiliently mounted so that it is constantly urged toward the pan or other operating device and regardless of the degree of distortion, the switch and the actuator are maintained at the same reference point or plane relative to the sensed operating surface.
It is, therefore, an object of the present invention to provide a new and improved electric switch actuator and mounting construction.
Another object of this invention is the provision of an improved electric switch actuator operated by relative movement of a surface to be sensed which will not be falsely operated by surfaces of a width less than a predetermined minimum.
Another object of this invention is the provision of an improved electric switch in accordance with the immediately preceding object in which the electric switch is resiliently mounted to maintain its relationship to an operating surface whose absolute position may vary.
A still further object of the present invention is the provision of an improved electric switch actuator having a lobed rotor mounted thereon for full rotation and in which the actuator is not moved sufiiciently to operate the switch until two lobes of the rotor are engaged by a surface to be sensed so that surfaces of lesser width than the space between the rotor lobes will not operate the switch.
These and other objects and features of the invention will be apparent to those skilled in the art from the following specification and the appended drawing, in which:
FIGURE 1 is a vertical sectional view showing a switch actuator and mounting means according to the present invention associated with a baking pan and an oil spray applicator;
FIGURE 2 is an enlarged sectional view showing the passage of a rolled edge pan reinforcement past the switch actuator without operating the switch;
FIGURE 3 is a view similar to FIGURE 2 but showing the switch operated by engagement of two lobes of the rotor by the bottom of the pan;
FIGURE 4 is a view showing the rotor of the switch actuator positioned at a dividing space between pan cavities wherein the spray device is reset by the switch actuator returning to non-operating position. i
In the diagrammatic representation of FIGURE 1, the framework for the pan spraying machine 11 includes a bottom horizontal plate 12 and a conveyor 13. Above the pan 14 is mounted a solenoid operated oil spray applicator 15 controlled by an electric circuit 16 which passes through an electric switch 17 of the normally-open type. This switch may be of the form commonly known as a microswitch, enclosed in an insulating housing with a plunger pin operator extending therefrom.
The switch 17 is mounted within a cavity in a housing 19 in which is rotatably mounted a transverse pin 2'1. Rigidly mounted on the pin 21 is an inverted-L-shaped spring operator 22 having one arm 23 engageable with the pin operator to operate the switch 17 and its other arm 24 engaging a wall of the housing cavity to rotate the 3 pin 21 into its non-operating position of FIGURES l, 2, and 4.
At the exterior of the housing 19, an actuating arm 25 is rigidly but adjustably mounted on the pin 21, as by a slotted end 26 and a stud 27. On the extended end of the actuating arm 25 is mounted a six-lobed rotor or star wheel 28 having lobes 29 therearound with depressions 31 therebetween. The star wheel 28 is mounted to be freely rotatable on the end of the actuating arm 25, as by a stud pivot 32.
The switch housing 19 is carried by a leaf spring arm 33 having one end rigidly mounted to the top of the housing at 34 and its other end mounted on the plate 12 by a stud 35 which may also carry a clamp 36 for a cable 37 enclosing the circuit wiring 16, cable 37 extending to the housing 19 to connect the circuit to the switch '17. The housing 19 extends through a slot 38 in the plate 12 and a finger 39 rigidly secured to the bottom of the housing limits upward movement thereof by engagement with the under surface of the plate 12.
The pan 14 which has been selected to illustrate .one application of the invention is conveniently for the baking of hot dog buns and has a plurality of cavities 41 therein separated longitudinally by spaces 46 and spacing portions 42. The pan is provided with a strengthening and bracing peripheral rolled edge 43 spaced at 44 from the adjacent pan cavity 41 by a pan portion 45.
The operation of the invention will now be described with relation to the figures of the drawing. Before a pan 14 encounters the switch mounting and biasing arm 33, the switch housing .19 will be in its uppermost position with the finger 39 engaging the undersurface of the plate 12. As a pan '14 moves toward the right, as shown in FIG- URE 1, on the conveyor 13, its forward rolled edge 43 engages the arm 33 and moves the switch housing 19 downwardly into the position shown in the drawing figures where it has a fixed reference with the bottom of the cavity 41, the under surface of the pan cavities being used to operate the switch in the specific embodiment illustrated.
FIGURE 2 shows the position of the switch housing 19, and the switch actuating arm 25 and, in dotted line, the star wheel 28 and the end of the pan after it has forced the switch housing downwardly and as its rolled edge 43 approaches the lobe 29Aof the star wheel 28. In full lines in FIGURE 2 and in FIGURE 1, the parts are shown with the rolled edge 13 having rotated the lobe 29A and the star wheel 28 clockwise and positioned itself in the depression 31A, this being effected without rotation of the switch actuating arm 25 relative to the housing 19.
As the pan 14 continues to move to the right, the lobe 29A will move up into the space 44, the star wheel 28 continuing to rotate freely without rotating the switch actuating arm 25. As the edge of the bottom surface defining the first cavity 41 engages the lobe 29B, the star wheel 28 will rotate the lobe 29C into engagement with the surface beneath the cavity and the star wheel is then prevented from freely rotating further. As the surface beneath cavity engages both of the lobes 29B and 29C, the switch actuating arm 25 is rotated clockwise into the position shown in FIGURE 3. This rotates the pin 21 clockwise and the arm 23 of actuator 22 engages the pin 18 and operates the switch 17 to closed position. This energizes the solenoid in the spray device and causes a spray ejection of oil onto the surface of the end cavity 41, thereby greasing it for a baking operation.
As the pin 14 continues toward the right on the conveyor 13, the switch 17 remains operated until the lobe 29C on the star wheel 28 enters the space-46 between the cavities 41, whereupon the star wheel is moved upwardly and actuating arm is rotated back counterclockwise under the action of the spring arm 24, thus permitting switch 17 to return to its normally open position. Opening of circuit 16 resets the spraying device '15, and when the next surface beneath a cavity engages both lobes 29D and 29C of star wheel 28, the actuating arm 25 will again be rotated counterclockwise under the action of the spring arm 24, thus permitting switch 17 to return to its normally open position. Opening of circuit 16 resets the spraying device 15, and when the next surface beneath a cavity 41 engages both lobes 29D and 29C of star wheel 28, the actuating arm 25 will again be rotated clockwise to close switch 17 and effect a spray of oil from the spraying device 15 into the second cavity 41 in the pan 14. This operation continues until all cavities in the pan have been sprayed. The pan then leaves the switch mounting arm 33 whereupon the housing 19 again moves upwardly into its non-operating position with the finger 39 engaging the under surface of the plate 12.
It is therefore seen that braces, strengthening ribs, rolled edges such as 43, and the like on the bottom of the baking pan 14 will not operate the switch 17 to cause a false spray from the device 15. Switch 17 will not be operated until the star wheel 28 is engaged by a surface having a width at least as great as the spacing between two of the lobes 29. All surfaces at the operating level which are not that wide cause only impotent free rotation of the star wheel 28 without rotation of the switch actuating arm and without operation of the switch.
The resilient mounting arm 33 for the switch housing 19 insures that the switch will be placed at the desired reference with respect to the switch operating surface and that the position of the operating surface may therefore vary between relatively wide limits while still effecting proper operation of the switch. This compensates for distortion such as caused by warping and bending.
While a specific application of the electric switch actuator of the present invention has been ilustrated in one embodiment thereof, it is to be understood that the invention is not limited thereto as many variations will be apparent to those skilled in the art, and the invention is to be given its hroadcest interpretation within the terms of the following claims.
1. In an electric switch:
a housing having a cavity therein;
a self-contained electric switch mounted in said cavity and having an operating plunger also disposed in the cavity;
an actuator for said switch;
means mounting said actuator for movement to operate the switch, said actuator being adapted to be moved by the passage of a surface therepast;
a rotor mounted on said actuator to be freely rotatble and having a plurality of lobes thereon projecting into the level of the surface which is to effect movement of said actuator, said rotor receiving surfaces of a width less than the distance between its lobes in the depressions therebetween to rotate the rotor without substantially moving the actuator, engagement of a surface wider than the distance between the lobes of said rotor with two of the lobes thereof causing said actuator to move into switch operating position;
a pin pivotally mounted in said housing across said cavity, said actuator including an arm rigidly secured to said pin at the exterior of the housing;
means mounting said rotor on said arm at the exterior of said housing spaced from said pin and for free rotation relative to said arm; and
a double-armed spring member mounted on said pin within said cavity, one of the arms of said spring member being positioned to engage said switch plunger to operate the switch, the other arm of said spring member engaging an abutment within said housing and serving to bias the actuating arm into a non-operating position.
References Cited STATES PATENTS Cunningham.
Walters 2006l.41 Oppman ZOO-61.41 X Kui'f 200-61.41 X
Bergmann 200-6l.41 X
FOREIGN PATENTS UNITED Germany.
ROBERT K. SCHAEFER, Primary Examiner.
R. A. VANDERHYE, Assistant Examiner.