US3405552A - Air detector for webs - Google Patents

Description

Oct. 15, 1968 J LUCKETT 3,405,552

AIR DETECTOR FOR WEBS 'Filed March 29, 1966 II. III!!! INVENTOR THOMAS J. LUCKETT w i fiw, a

T'TORNEYS United States Patent 3,405,552 7 AIR DETECTOR FOR WEBS Thomas J. Luckett, Suitland, Md. (7901 Pennsylvania Ave. SE, Washington, 11C. 20028) Filed Mar. 29, 1966, Ser. No. 538,367 7 Claims. (Cl. 7337.7)

ABSTRACT OF THE DISCLOSURE This disclosure has to do with a detector particularly adapted for use in an atmosphere laden with dust and other minute foreign matter, including printing material mist and wherein the detector is particularly adapted for detecting ruptures and voids in a moving web. The detector includes a bracket having means for mounting the same on a web supporting apparatus and includes a fluid nozzle to be disposed on one side of a web and a direct action control member hingedly carried by the bracket on the opposite side of a web and having a reaction portion in opposite alignment with the fluid nozzle for direct actuation of the control member by fluid from the fluid nozzle only in the absence of an intermediate web portion.

This invention relates in general to new and useful improvements in detectors for webs, and more particularly to an air detector for paper webs.

This invention particularly relates to detectors to be utilized in conjunction with machinery having webs travelling at high speeds therethrough. Such machinery includes printing presses. In the past both mechanical and electronic detectors have been utilized. The electronic detectors have been in the form of electric eyes and while electric eyes are known to perform satisfactory in many environments, the dust passing off of the fast travelling paper webs, as well as ink mist, frequently coated the light lens so as to render the electric eyes ineffective. While the paper dust and ink mist did not present a material problem with respect to conventional mechanical detectors of the type which ride on the web, the mechanical detectors in use prior to this invention had a more material deficiency. When the paper web had a defect therein, such as a slime hole or a slight rip, the mechanical detectors would drop into the opening in the paper while detecting the defect and tear the paper out of the mechanism while shutting the mechanism down.

In accordance with this invention, a detector which is suitable for use in conjunction with a paper web and under conditions of paper dust and ink mist has been provided, the detector being of the mechanical type but being of a construction wherein direct contact with the web is eliminated at all times.

Another object of this invention is to provide a novel detector which utilizes an air stream which is directed against the moving web and which has associated therewith a lever which is normally unaffected by the air stream, but which is tripped should the web have an opening therein through which the air stream may pass.

Another object of this invention is to provide a novel detector which utilizes an air stream, the detector being particularly advantageous for use in conjunction with a moving paper web in that it is self-cleaning.

Another object of this invention is to provide a novel detector which may be readily incorporated in a printing press apparatus for detecting the defects in webs, the detector being of a simple construction so as to be inexpensive and being readily mountable on existing press structure.

Another object of this invention is to provide a novel air detector for moving paper webs of a printing press, the detector being of a construction wherein the opera- 3,405,552 Patented Oct. 15, 1968 tion thereof is positive and at the same time contact with the web is completely eliminated.

A further object of this invention is to provide an air detector for detecting defects in a rapidly moving paper web moving through a printing press and wherein the detector is of a construction so as to be protected when unintentionally engaged by the moving web should rupture of the web occur in the vicinity of the detector.

With the above and other objects in view that will hereinafter appear, the nature of the invention will be more clearly understood by reference to the following detailed description, the appended claims and the several views illustrated in the accompanying drawing.

In the drawing:

FIGURE 1 is a schematic perspective view of a detector formed in accordance with this invention and shows the relationship thereof with respect to a moving web;

FIGURE 2 is a schematic perspective view similar to FIGURE 1 and shows the detector detecting a rupture in the web.

FIGURE 3 is a perspective view of the detector mounted on a support bar of a printing press;

FIGURE 4 is a transverse vertical sectional view taken along the line 44 of FIGURE 3 and shows a web positioned within the detector;

FIGURE 5 is a vertical sectional view taken along the line 5-5 of FIGURE 4.

FIGURE 6 is a horizontal sectional view taken along the line 6-6 of FIGURE 5.

FIGURE 7 is a fragmentary perspective view of the detector having a modified form of air control.

Referring now to the drawing in detail, it will be seen that there is illustrated in FIGURE 3 a typical installation of the detector which is the subject of this invention, the detector being generally referred to by the numeral 10. The detector 10 includes a mounting bracket 11 which is formed of an elongated horizontal arm 12 and a depending vertical arm 13. The connection between the arms 12 and 13 is reinforced so as to retain the angular relationship of these arms. The horizontal arm 12 is provided with suitable hangers 14 for detachably suspending the detector 10 from a frame member of an apparatus through which a running web passes, the frame member 15 being a conventional member of such apparatus including printing presses.

A tubular housing 16 extends from the lower end of the vertical arm 13 in underlying relation to the horizontal arm 12. The housing 16 terminates remote from the vertical arm 13 in an upwardly opening extension 17.

Referring now to FIGURE 5 in particular, it will be seen that the horizontal arm 12 is of a two-piece construction and includes a lower portion 18 and an upper portion 19. The hangers 14 are preferably carried by the upper portion 19. Also, it is to be noted that the upper portion 19 has formed in the underside thereof a passage 20. The passage 20 terminates at one end in alignment with an inlet passage 21 formed in the lower portion 18 of the horizontal arm 12 at the connection thereof with the vertical arm 13. A discharge passage or nozzle 22 is formed in the lower portion 18 remote from the vertical arm 13. It is to 'be noted that the discharge passage or nozzle 22 is aligned with the housing extension 17.

The housing 16 has mounted therein adjacent the vertical arm 13 an electric control switch 23 which may be in the form of a conventional microswitch. The switch 23 has a control element 24 which is depressible to change the electrical connection of the switch 23. There is also mounted within the housing 16 a switch control member which is generally referred to by the numeral 25. The switch control member 25 includes an elongated arm or lever 26 which is hingedly mounted at the end thereof disposed adjacent the vertical arm 13 by means of a hinge 28. The opposite end of the arm or lever 26 carries a reaction member 27 which is seated within the housing extension 17 in alignment with the nozzle 22. It is to be noted that the reaction member 27 is of a concave construction so as to absorb a maximum of the force of the air stream passing out from the nozzle 22.

The vertical arm 13 has mounted thereon an air control valve 29 which may be of any conventional type. The air control valve 29 includes an inlet fitting 30 and a discharge fitting 31, the discharge fitting 31 being coupled into the vertical arm 13 in communication with the inlet passage 21. The preferred form of air control valve 29 is solenoid operated and includes a solenoid actuator 32 which is suitably connected to the valve element 33 thereof.

Referring now to FIGURES l and 2 in particular, it will be seen that the solenoid control element 32 may be connected in series with the electrical circuit for the particular apparatus through which a web is passing and which web is to be detected. The electrical control circuit will include the usual start-stop switch 43 and the switch 23 is connected in series with the switch 43 and the solenoid 32.

At this time it is pointed out that the movement of a web, such as the web 34, through an apparatus is controlled by a plurality of rolls 35. A majority of these rolls are driven so as to effect the movement of the web 34.

The web 34 will have numerous defects which are undesirable and which must be detected. When these defects are detected, it is desirable that the apparatus such as a printing press, be shut down and the detective section of the web removed. It is also highly desirable to immediately shut down the apparatus in the event there should be a complete rupture of the web.

In the normal operation of the detector 10, the rapidly moving web 13 passes between the horizontal arm 12 and the housing 16. The solenoid 32 is retained in a position holding the valve element 33 in the flow position of the valve 29 so that air passes through the arm 12 and out through the nozzle 22 in the form of a jet. The air jet is directed against the web 34 and is deflected thereby so as to have no effect whatsoever on the control member 25 or the normally closed switch 23. However, when there is an opening in the web 34, or the web 34 is suddenly ruptured, the web 34 will fail to deflect the air jet from the nozzle 32, and this air jet will impinge upon the reaction member 27, so as to move the control member 25 away from the horizontal arm 12 and to open the switch 23. When the switch 23 is opened, the apparatus is immediately shut down. At the same time, the circuit to the solenoid 32 will be opened and the valve element 33 will be returned to its closed position, thereby shutting off the supply of air to the nozzle 22.

The advantages of the detector as compared to mechanical detectors which engage the rapidly moving web and the more expensive photoelectric detectors will be apparent. A further advantage is that most web handling equipment has associated therewith a supply of compressed air, thereby eliminating the necessity of providing a separate air source for the detector. Inasmuch as the detector may be conveniently mounted on existing supports of the apparatus, the cost of installing the detectors is held to a minimum.

Another advantage of the detector 10 is that it is self-cleaning. It is quite apparent that the nozzle 22 cannot clog in that air constantly flows therethrough during the movement of the web 34. In a like manner, the paper dust and ink mist will have no direct effect on the operation of the detector 10. The slight amount of dust or ink mist which may settle on the reaction member 27 will not be sufiicient to trip the switch 23. Furthermore, the detector 10 is self-cleaning in that when a break or opening in the web 34 occurs, the air jet will impinge against the reaction member 27 and clean the same. Furthermore, certain of the air will pass around the reaction member 27 and enter into the housing extension 17 to effect the cleaning thereof. To facilitate cleaning of the housing extension 17, slots 36 are formed in the lower portions of the vertical walls adjacent the base of the tubular member 16.

Although a convenient source of compressed air is usually available, when it is desired to eliminate a central source of compressed air for one reason or another, including the desire to eliminate piping, the detector may be self-contained. "In FIGURE 7, the detector 10 is illustrated as having the valve 29 omitted and there being provided in lieu thereof a small blower 37 which is driven by a wheel 38 which is, in turn, driven from the roller 35. If desired, means may be provided for vertically adjusting the wheel 38 so as to disengage from the roller 35 and thus render the detector 10 ineffective.

Although the detectors have been shown in horizontal positions with the bracket 11 disposed uppermost, it is to be understood that the detectors may operate under varied conditions of orientation. Also, it is pointed out here that under certain circumstances the switch 23 may be desired to be of the normally opened type and is closed by the movement of the control member 25 so as to complete a circuit to a machinery controlling relay (not shown). In view of the fact that the orientation of the detector 10 may vary, various arrangements of mounting of the detector have not been illustrated.

Although only two preferred embodiments of the invention have been specifically illustrated and described herein, it is to be understood that minor variations may be made in the detector without departing from the spirit and scope of the invention, as defined in the appended claims.

I claim:

1. A detector particularly adapted for detecting ruptures and voids in a moving web, said detector comprising a bracket having means for mounting the same on a web supporting apparatus, a fluid nozzle carried by said bracket, a direct action control member hingedly carried by said bracket and having a reaction portion in opposed alignment with said nozzle for direct actuation of said control member by fluid from said nozzle only in the absence of an intermediate web portion, and a control element connected to said control member for actuation thereby, said detector being particularly adapted for use in an atmosphere laden with dust and other minute foreign matter and including a protective housing for said control member and said control element.

2. The detector of claim 1 wherein said detector is particularly adapted for use in conjunction with a paper web passing through a printing apparatus and wherein said laden atmosphere includes paper dust and printing material mist, said bracket having means for connecting said fluid nozzle to a pressurized air source, and control means operable in response to the operation of an associated printing apparatus for assuring a continuous supply of air through said fluid nozzle during the operation of an associated printing apparatus whereby said detector is self cleaning.

3. A detector particularly adapted for detecting ruptures and voids in a moving web, said detector comprising a bracket having means for mounting the same on a web supporting apparatus, a fluid nozzle carried by said bracket, a control member hingedly carried by said bracket and having a reaction portion in opposed alignment with said nozzle, and a control element connected to said control member for actuation thereby, said reaction portion being of a concave shape to assure a maximum reaction from fluid under pressure from said nozzle.

4. A detector particularly adapted for detecting ruptures and voids in a moving web, said detector comprising a bracket having means for mounting the same on a web supporting apparatus, a fluid nozzle carried by said bracket, 21 control member hingedly carried by said bracket and having a reaction portion in opposed alignment with said nozzle, and a control element connected to said control member for actuation thereby, said bracket having means for connecting said fluid nozzle to a pressurized air source including a self-contained air pump having means for driven engagement with a web supporting roll.

5. The detector of claim 1 wherein said bracket is generally L-shaped and includes first and second arms, said housing being carried by said second arm and extending in generally spaced parallel relation to said first arm, and said second arm having means for connecting said fluid nozzle to a pressurized fluid source.

6. The detector of claim 1 wherein said housing has an extension receiving said reaction portion, and said housing extension opens towards said fluid nozzle.

7. The detector of claim 6 wherein said housing extension is self-cleaning by fluid from said fluid nozzle and has fluid escape openings below said reaction portion.

References Cited UNITED STATES PATENTS 2,900,468 8/1959 Joy. 3,188,856 6/1965 Schneider 7337.7

FOREIGN PATENTS 442,365 2/ 1936 Great Britain.

DAVID SCHONBERG, Primary Examiner.

WILLIAM HENRY II, Assistant Examiner.

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