US3032691A - Sensitive contact switch for material guiding device - Google Patents

Description

y 1962 G. CUBELLIS 3,032,691

SENSITIVE CONTACT swncn FOR MATERIAL GUIDING DEVICE Filed March 15, 1957 2 Sheets-Sheet 1 iii -34 m i l I i i I 20 FIG. I

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GUIDO CUBELLIS ATTORNEY G. CUBELLIS May 1, 1962 SENSITIVE CONTACT SWITCH FOR MATERIAL GUIDING DEVICE Filed March 15, 1957 2 Sheets-Sheet 2 INVIZNTOR. GUIDO CUBELLIS ATTORN FIG. 7

United States Patent 3,032,691 SENSITIVE CONTACT SWITCH FOR MATERIAL GUIDING DEVICE Guido Cubellis, 2 Anderson Ave., West Warwick, RI. Filed Mar. 15, 1957, Ser. No. 646,387 1 Claim. (Cl. 317-124) My present invention relates to devices for guiding the edge of materials and more particularly to a sensitive switch for controlling such devices.

, The principal object of the present invention is to provide a sensitive switch for contacting the edge of light and flimsy materials.

Another object of the present invention is to provide a sensitive switch which will be unelfected by lint, dust or other foreign matter.

A further object of the present invention is to provide a sensitive switch for guiding material which is adjustable for position or swing.

Another object of the present invention is to provide a sensitive switch in which the electrical portions are remotely positioned from the work to minimize the danger of explosion in the presence of explosive fumes.

Another object of the present invention is to provide a sensitive material guiding switch which is simple in construction and easy and economical to manufacture and assemble.

With the above and other objects and advantageous features in view, my invention consists of a novel arrangement of parts, more fully disclosed in the detailed description following, in conjunction with the accompanying drawings, and more particularly defined in the appended claim.

In the drawings,

FIG. 1 is a front elevation of a switch embodying my invention.

FIG. 2 is a transverse section taken on line 2-2 on FIG. 1. Y

FIG. 3 is a bottom view of the left photo-cellmember.

FIG. 4 is a longitudinal section of the device in FIG. 1, with the switch in displaced position.

FIG. 5 is a vertical section through the photo-cell member shown in FIG. 3.

FIG. 6 is a section taken on line 6-6 on FIG. 3.

FIG. 7 is a diagram of the electrical hookup.

When material is fed from a roll or coil to a machine, it is often important that the feed be accurate and straight. For example, cloth must be fed with straight edges into a tenter frame, paper into a press, or strip metal into a stamping press. The method of keeping the material properly aligned is to provide a device, either mechanical, hydraulic or pneumatic, for shifting the material from one side to the other in response to a contact switch having a sensitive finger at the edge of the material. In my Patent No. 2,801,308, entitled, Contact Switch for Material Guiding Device, issued July 30, 1957, I provide a novel mechanical switch having many advantages over the conventional types in use. However, in many instances the material is extremely light and flimsy. For example, cheese-cloth, tissue paper or fine silk or nylon net. It will be found that these materials will tend to curl and bend against the pressure of the switchfinger making the guide mechanism inaccurate.

To overcome the very light pressure of the flimsy material highly sensitive switches must be used. Attempts have been made to use photo-electric cells at the edge of the material so that if there is a movement of the material in one direction it will cut off light to the cell and in the opposite direction will allow the light to hit the cell. In

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use however, it has been found that lint, threads, and other foreign substances gathered on the lense and interfered with the proper operation of the switch. This has been partially avoided by adding a source of compressed air for blowing the switch clean. But the material is often moist and the lint clings to the cell.

The present invention is designed to provide a highly sensitive switch using a photo-electric cell in combination with a mechanical finger in such manner that the cell will be kept virtually clean at all times. The arrangement of the present invention also permits easy adjustment for sensitivity and swing. Furthermore, many materials are soaked in solvents giving off explosive fumes and the present invention permits the electrical portions of the device to be positioned remotely from the material and thus minimize the danger of explosions.

Referring more in detail to the drawings, the device is normally mounted in a rectangular housing 10 having a front cover 11 and an open slot 12 in the bottom wall through which the sensitive finger extends. Referring to FIG. 2, a rigid inverted U-shaped bar 13 is mounted centrally of the rear wall of the housing by providing a pair of spaced transversed strap members 14 bolted to the rear Wall of the housing. The vertical leg 15 of the member 13 is frictionally engaged by the straps 14 but permitting vertical sliding movement. The horizontal leg 16 extends forwardly in the housing and then terminates in the second vertical leg 17 which is shorter than the leg 15. An adjustable screw 18 extends through the top of the housing and is locked therein by the washer 19 extending'into the upper unthreaded portion of the screw. The screw 18 threadedly engages the horizontal arm 16 of the member 13. With this arrangement turning moveintent of the screw 18 will cause the U-shaped member 13 to slide upwardly or downwardly in the straps 14 to provide vertical adjustment for a purpose hereinafter to be described.

Now referring to FIGS. 1, 2 and 4, I provide a plate 20 broad in the center and narrowing to two wing like portions at each side. The plate 20 is provided at the top and bottom edges in the center with complementary arcuate portions 21 and 22. From the arcuate portions the wings on each side taper to straight shoulders or edges 23 and 24 to the left and right, the edges 23 and 24 being horizontal and at right angles to the vertical axis of the plate as shown in FIG. 1. Extending through the plate 26 is a bearing 25 in the form of a small rod extending through the plane of the plate and having conical openings at each end. The location of the bearing 25 is governed by the center of gravity of the plate 20 and it should be positioned in the exact point of the center of gravity so that the plate will be perfectly balanced. The member 13 is provided with adjustable needle- pointed screws 26 and 27 extending towards each other from the vertical arms 15 and 17. The needle points 26 and 27 enter the ends of the bearing member 25 to provide a needle bearing support for the plate 20. With the plate perfectly balanced and the friction reduced to a minimum the plate 26 will move at the slightest touch.

The contacting finger constitutes a thin strip of metal 28 twisted at its lower end 29 so that the plane of the strip will be at right angles to its movement. The strip 28 ends upwardly behind the plate 20 and its upper end is bent over at 30 to grasp the upper arcuate portion 22 of the plate. At the lower edge of the plate 20 the strip 28 is provided with a tab 31 which is mounted on the strip by a screw 32, the tab extending over the bottom edge 21 of the plate. With this arrangement the screw 32 can be loosened and the strip 28 swung arcuately to the right or Patented May 1, 1362 left on the plate. This provides an adjustment for position as will hereinafter be described. At a point where the strip 28 passes the bearing member 25 an opening must be provided for the bearing through the strip as shown in FIG. 2.

The mechanical arrangement heretofore described comprises the mechanical contact portion of the switch. The electrical impulse for operating the edge guiding device is obtained by means of a pair of photo-cell elements mounted in the housing it), the element 33 at the left and the element 34 at the right as shown in FIGS. 1 and 4. Each photo-cell member is constructed as shown in FIGS. 3 to 6 inclusive. Each member comprises a rectangular block or base 35 made of Bakelite or similar dielectric material having a slot 36 extending inwardly from one long edge approximately two thirds of the way through the block. As shown in FIGS. 5 and 6 a recess opening 37 extends into one edge of the block and terminates in a smaller opening 38 communicating with the slot 36. V Opposite the opening 38 a small opening 39 extends through in alignment therewith. A small pencil flash light blub 40 preferably of low voltage is mounted in the opening 37 against the action of a spring 41 and held in place by a cotter pin 42 which extends through the block as shown in FIG. 6. The pin 42 also servs as one of the electrical connections to the bulb. The spring 41 permits easy removal of the bulb after the pin has been drawn out. The bulb 4t is designed to throw a beam of light through the opening 38 across the slot 36 into the opening 39. Mounted in the opening 39 is a photo-electric cell 43 designed to operate in response to the light from the bulb 40. An inverted U-shaped plate 44 is mounted over the opening 39 with the sides of the U-shaped portion strad dling the block 35. The plate 44 is provided with a thin slot 45 as shown in FIG. 4 through which the light from the bulb 40 must travel to energize the cell 43. To keep the face of the photo-cell 43 clean and free from dirt the plate 44 is slightly raised from the surface of the block as shown in FIG. 5 and a translucent strip of material 46 is slipped under the plate. The strip 46 may be glass or plastic or any other similar material. The strip 46 serves to seal the opening 39 against dust and dirt but permits light from the bulb 4t entering the slot 45 to pass through it to the cell 43. The strip 46 may be pulled out at any time for cleaning.

The photo- cell members 33 and 34 are mounted as shown in FIGS. 1 and 4 so that pivotal movement of the plate 20 will swing the wing sections to the plate through the slots 36. In initially adjusting the plate 20 it must first be determined whether it is to be with shielded or unshielded light. If the operation is to be with unshielded lights then the set screw 18 is adjusted to pull the plate 2t) upwardly or downwardly until the flat horizontal edges 23 and 24 at the wing ends are just below the slots 45 in the plates 44. The closer they are to the slots, the finer the adjustment; the further they are from the slots the more play in the finger 2.9 before the adjustment is made.

Before describing the operation of the switch it must be properly hooked up as shown in FIG. 7. It should be noted that the light 4% and photo-cell 43 are the only parts shown in the diagram which are actually located in the housing llti. It is contemplated that the other operative electrical parts be positioned in a separate housing remote from the. work and connected to the housing 10 by the necessary wiring. This will minimize the danger of explosion from explosive fumes. A source of 11 V. AC. current 47 is connected to a DC. rectifier 48. The bulbs 4 are connected in series, a resistance 49 cutting the voltage to the proper value. The DC. current is shunted by a resistance and condenser 51 and supplies the photo-cells 43. The photo-cells 43 are connected to terial to compensate for lateral shifts in response to the switch of the present invention.

The operation of the switch is fairly simple. The housing it is mounted above the edge of the material being guided with the finger portion 29 touching the edge of the material. It should be noted that two thick screws 56 are mounted in the upper portion of the plate 20 to counterbalance the plate. If the screw on the left is removed, the one on the right will cause the finger 29 to swing to the left with an extremely light pressure. If the screw on the right is removed then the screw will cause a slight swing to the right. It will be found that the device is extremely sensitive to very light pressures. Since the plate does not actually contact a switch it is free to swing at the slightest touch. The adjustable screw 18 is set so that the flat portions of the plate 23 and 24 are positioned just below the slots 45 in the photo-cell member 44. If the material should swing to the right as shown in FIG. 4 the right wing of the plate 20 will shield the slot 45 and deenergize the photo-cell and one of the relays 52 or 53 to throw the right hand switch and cause the material to be shifted back to the left. The finger 29 will follow the material until both slots 45 are unshielded. The same operation takes place if the swing is in the opposite direction. The portions 23 and 24 of the plate control the amount of permissable swing before the photo-cell is deenergized. If they are drawn up close to the slots 45 very little swing is permitted. If they are dropped away from the slots 45 more swing is permitted. Where the device is operated with the photo-cells initially shielded, then the swing of the plate will unshield one cell and energize the relay. The operation is the same whichever method is used.

The construction of the machine sometimes does not permit the housing it) to be positioned exactly over theedge of the material. In such cases the screw 32 on the strip 28 is loosened and the strip rotated along the edges 21 and 22 at an angle to the vertical axis of the plate. This will permit the strip to be positioned at an angle touching the edge of the material, such as the position shown in FIG. 4, while the plate is in horizontal position such as shown in FIG. 1. It should also be noted that the light bulb 44) in each cell unit is so close to the photocell 43 that sufficient current variations are set up to operate the relays 52 and 53 and switches 54 and 55 Without the need of an amplifier circuit. This makes the device simpler and more economical to install. It should also be noted that the device can be adapted for a shielded operation where the wing portions 23 and 24- of the plate normally cover the slots 45 and will uncover them when they swing into the position shown in FIG. 4.

With the electrical circuit shown the device is balanced and will become inoperative if either of the lights or cells should fail. Other advantages of the present invention will be readily apparent to a person skilled in the art.

I claim:

A control device for operating a material guiding mechanism comprising a pair of switches for energizing said material guiding mechanism, a vertically mounted housing, a pair of photo-electric cell and light units in said housing for energizing said switches, a flat elongated tongue pivotally depending from said housing for engaging the edge of the material to be guided, and a plate mounted on. said tongue for shielding and unshielding said lights in response to pivotal movement of said tongue, each of said units comprising a rectangular dielectric block, said block havinga transverse slot extending inwardly from one side edge, said block having longitudinal openings in alignment communicating with said slot, a photo-electric a pair of relays 52 and 53, the relay 52 operating the switch 54 the relay 53 operating the switch 55. The

switches 54 and 55 are connected by suitable wiring to the mechanism (not shown) 'used for moving the macell mounted in one opening, a light bulb mounted in the opposite opening facing said cell, and a shield covering said li t bulb opening, said shield having a narrow slot.

(References on foliowing page) References Cited in the file of this patent UNITED STATES PATENTS 6 Gulliksen Mar. 30, 1937 Gale Apr. 30, 1940 Cockrell Apr. 8, 1941 Dutter May 27, 1941 Haskins Aug. 16, 1955 Cubellis July 30, 1957

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