US3260435A - Fluid pressure operated sensing system - Google Patents

Description

July 12, 1966 P. w. JAcoBsEN FLUID PRESSURE OPERATED SENSING SYSTEM Filed June 4, 1964 United States Patent O 3,260,435 FLUID PRESSURE OPERATED SENSlNG SYSTEM Paul W. Jacobsen, Kiel, Wis., assignor to H. G. Weber and Company, Inc., Kiel, Wis., a corporation of Wisconsin Filed June 4, 1964, Ser. No. 372,650 3 Claims. (Cl. 226-15) This invention relates to an edge alignment control system and particularly to such a system which establishes a neutral range of edge positions and which responds to errors in web position in each of two opposite lateral directions from the neutral range of positions.

It is an object of the present invention to provide edge alignment control systems utilizing mechanically ac-tuated switching means responsive to relatively slight mechanical output movements from fluid pressure error sensing means associated with the web position sensing head.

It is another object of the present invention to provide a system for indicating the position of the edge of a web or the like which has increased sensitivity to changes in web position.

A further object of the invention is to provide an edge alignment sensing system utilizing commercially available miniature switches but providing for a relatively rapid response time to errors in web position as compared to prior systems utilizing such switches.

Other objects, features and advantages of the present invention will be apparent from the following detailed description, taken in connection with the `accompanying drawing, in which the single figure is a diagrammatic illustration of an edge alignment control system in accordance with the present invention.

The presen-t invention relates particularly to improvements over the edge alignment control systems illustrated in my copending applications Serial No. 280,600 filed May 15, 1963, and Serial No. 328,652 filed December 6, `1963. As disclosed in detail in said copending applications, a sensing head in accordance with the present invention may be provided with a plurality of sets of multiple cooperating fluid jets, each set of fluid jets being responsive to the presence or absence of a material. In one embodiment, there are only two opposed jets in each set, but in the preferred embodiment, there are three jets in each cooperating group, one on one side of a receiving space and two on the opposite side. Two sets of such cooperating jets may be provided for defining a neutral zone of web positions therebetween. Thus, referring to the drawing Ithere are diagrammatically indicated jet defining means 31, 32 and 33 and 41, 42 and 43. The fluid jet means 31-33 and 41-43 may comprise suitable fluid nozzles or conduits having fluid passages terminating in iluid orifices for delivering fluid in a stream or jet into respective material receiving spaces 34 and 44. The axes of the fluid jet means 32, 33 and 42, 43 may be directed toward the fluid jet means 31 and 41, respectively, so tha-t in the absence of a material in the receiving spaces 34 and 44, respectively, the fluid jets converge adjacent the orifices of fluid jet means 31 and 41, respectively, so as to create fluid -barriers across the orifices of fluid jet means 31 and 41 which inhibit discharge of fluid from fluid jet means 31 and 41. In an actual physical embodiment, the jet means 32, 33 and 42, 43 may preferably lie in respective offset planes directed longitudinally of the direction of web movement. This actual arrangement is preferred Patented July 12, '13136 rice ysince it enables the jets to be very closely spaced in the lateral direction (which is indicated by the double headed arrow 50). A portion of the web is indicated at 51 having an edge 51a which is located in `the neutral zone between the two sets of fluid jets 3133 and 41-43.

As illustrated, where a gas such as air is applied to the jet means, a plant air source 60 of abou-t 80 lto 100 pounds per square inch above atmospheric pressure may be used as a source of fluid under pressure. The plant air is suitably filtered and delivered to a conduit 61 which branches into a pair of conduits 62 and 63. The conduit 62 is provided with a 0 to 5 pound per square inch pressure regulator component 67. The component 67 provides pressures in lines 75, 76, 77 and 73 between 0 and 5 pounds per square inch. A series of metering orifices 81-85 are provided for regulating the iiow rates in lines 91, 92, 93, 101 and 102 (the reference characters designating the respective lines corresponding to the reference characters designating similar lines in said copending application Serial No. 280,600). Static pressure lines 95, 96, 105 and 106 preferably tap lines 91, 92, 101, 102 so as to provide a measure of the static pressure in these lines which lead to the fluid jet means 31, 32, 41, 42, respectively.

The metering orifices 81-85 are so proportioned that when the pilot jets 33, 43 are obstructed output lines 91 and 101 have a lesser static pressure as sensed at lines 95 and 105 than the static pressures of lines 92 and 102 as sensed at lines 96 and 106. These static pressures are with respect to the condition where the receiving spaces 34 and 44 are completely obstructed. Output line 93 is shown as connected with jet means 33 and 43 and Ihas a sucient ow velocity to cause the static pressure in lines 9S and 105 to greatly exceed the static pressure in lines 96 and 106 when the - pilot jets 33 and 43 are present adjacent the orifices of jet means 31 and 41.

With the pilot jet means obstructed as illustrated for the pilot jet means 43, the static pressure associated with the sensing jet means such as 41 is reduced relative to the static pressure associated with the reference jet means such as 42. Thus, in the condition of the system as illustrated in the drawing the pressure in chamber of diaphragm actuator 111 exceeds the pressure in chamber 112 of diaphragm actuator 113. Similarly because of the unobstructed condition of pilot jet means 33, the pressure in sensing line 95 exceeds the pressure in reference line 96, and the pressure in chamber 115 of diaphragm actuating means 116 exceeds the pressure in chamber 117 of diaphragm actuating means 118. In the illustrated embodiment, the diaphragms 121-124 may be considered to be of a resilient material to accommodate axial shifting of the rods 131, 132 and 133, 134 connected therewith in the axial direction for a required distance in each direction from a central position. The opposite chambers 141- 144 of the devices 111, 113, 116 and 113 may be considered as being vented to atmosphere Iby means of apertures in the walls thereof through which the respective -rods 131-134 extend and as indicated at 146 for rod 131.

The rods 131 and 132 may be considered as extending into opposite ends of a cylindrical bore 151 of a block 152. Set screws are indicated at 153 and 154 for adjusting the overall length of the mechanical output means associated with diaphragm actuating means 111 and 113. Similarly, the rods 133 and 134 extend into a cylindrical bore 156 of a block 157 and are locked at selected positions by means of set screws 158 and 159 to determine the overall length of the mechanical output means assocoated with diaphragm actuating means 116, 118. The blocks 152 and 157 carry actuator members 152a and 157a for operating levers 161 and 162 which cooperate with respective switches approximately 3/32 inch of a mechanical input device. The system is so arranged that switch 163 is actuated when the edge 51a of the web 51 moves to the right of its correct position so as to obstruct the pilot jet from pilot jet means 33, while the switch 164 is actuated when the edge 51a of web 51 moves to the left from the correct position and moves out of obstructing relation to the pilot jet associated with pilot jet means 43.

An edge alignment control 180 is rendered operative in one direction by switch 163 through lines 171 and 172, and the edge alignment control 180 is rendered operative in the opposite direction by switch 164 through lines 173 and 174. The switches 163 and 164 could also be used to actuate suitable indicating means (not shown) which is independent of the alignment control system; however, the indicating means could be incorporated directly in the alignment control 180. The edge alignment control 180 may comprise appropriate solenoid operated valves as shown in the fifth figure of my copending application Serial No. 328,652. Also included in the edge alignment control 180 is a power source to energize the solenoid devices when switches 163 and 164 are actuated at respective different times.

Switches 163 and 164 are of the miniature type requiring little actuating force and a minimum of actuator travel. Therefore, the edge alignment control 180 will make the necessary correction immediately after the sensing head senses a deviation of the edge 51a from its normal position.

A stroke limiting bar bar portion 155a for receiving movement thereof.

155 is provided with a recess the block 152 to limit the The preferred distance center position; therefore, the length of the recess portion 155:1 in the bar 155 should be 1/32 inch greater than the length of the block 152. As shown in the drawing, the lever 161 pivots about a fixed pivot point 161a. As viewed on the drawing, the lower portion of the lever 161 below the pivot 161:1 has a dimension of 'Vs inch and the upper portion above the pivot point 161a has a dimension of 2% inches. The switch 163 includes an actuating arm 209 pivotally mounted at 209a and arranged to engage a switch operating stem 163a. Compression spring 170 may urge the switch contact 163b toward its closed position. The lever 161 may engage the switch arm 209 at a point 1/8 inch from the free end indicated at 161b. The point at which the lever 161 engages the switch lever 209 is thus 25/3 inches above the It can be seen, therefore, that the the block 152 will factor of three at the point 161b to provide a maximum actuating travel of point 161b of 1%2 inch. The groove 155a limits movement of the block 152 to prevent exertion of undue force on the switch lever 209 and to substantially eliminate overtravel in the switch 163.

Switches 163 and 164 are arranged in such a manner that actuation thereof is obtained by the total amplified stroke of the levers 161 and 162 without using the inherent overtravel in the switches 163 and 164. Also, the switch 164 may have the operating stem 171 held in the open position by spring means 172 as shown.

The actuator 162 has the same configuration as the actuator 161, and the stroke limiting bar 160 has the same configuration as the bar 155.

When the web 51 moves out of obstructing relation to the pilot jet means 43, the pressure in chamber 112 will exceed the pressure in chamber 110, and actuating rods 131 and 132 together with block 152 and the lower end of the member 161 will move to the right from a central position, thereby allowing the switch 163 to close. When the web 51 returns to the position indicated, again obstructing the pilot jet means 43, the actuating rods 131, 132 associated with diaphragms 121 and 122 will at least return to a central neutral position corresponding to the case where the pressures in chambers and 112 are equal, for example. Alternatively and as required for the specific example herein disclosed, the pressures or areas of the respective diaphragms may be such that the diaphragms 121 and 122 are displaced to the left from their Central vertical disposition when the edge of the web is in the correct position. In any event, it is preferred that with the web 51 out of obstructing relation to jet means 43, the actuating rods 131 and 132 together with block 152 will assume a position with the lever 161 substantially in abutting contact with the arm 209 of the switch 163 with the switch closed. With this arrangement and with the switch specified, the switch will be actuated during the first 1/32 inch of travel of the stems 131 and 132 and block 152 and there will be substantially no overtravel of the switch stem 16311 either in moving to its switch-closed position or in moving to its switchopen position.

Summary of operation of the illustrated embodiment In the embodiment shown, when the web 51 moves to the right from its obstruct the pilot Jet means 33,

shift the members coupled with the diaphragms 123 and 124 to the left allowing the switch 164 to 134 and block 157 may return to an extreme right hand position. In closed position of switch 164, the lever 162 is still substantially in abutting contact with the switch arm 210 and the switch arm is still substantially contacting the actuating stem 164a of the switch 164 so that there is substantially no overtravel of the stern 164a in moving between its switchopen and switch-closed positions.

If the web deviates to the left from the correct position indicated in the drawing, the pilot jet means 43 becomes unobstructed and causes the internal pressure in the line 105 to increase, increasing the pressure in actuating chamber 112 of the diaphragm actuating means 113 so as t0 shift the block 152 to the right and allow the switch 163 to close.

In this event, a slight shifting of the blocks 152 and 157 will actuate the respective switches 163 and 164 with a minimum time delay.

The system s poised for fast action at all times while in operation since the sensing head 10 constantly maintains air pressure in the actuating chambers 110, 112, and 117. The relative pressures in the opposing chambers are such that there is substantially no wasted travel of the diaphragms 121-124 as the diaphragms are actuated between their 'respective operating positions. This condition' contributes to the fast reaction time as a prime factor.

When the illustrated system is used with a liquid actuating medium, such as a city water supply, it is preferred to omit the pilot jets 33 and 43 and to connect only the sensing jet water lines 91 and 101 to the diaphragm actuators. Thus with a water system, jets 31 and 32 and 41 and 42 would be used and water lines 91 and 1M would be coupled to the diaphragm chambers 115 and 112 by water lines 95 and 105, respectively, as shown in the drawing. It is preferred, however, with a liquid actuating system to introduce air at a predetermined adjustable pressure in the chambers 110 and 117 rather than connecting these chambers to water lines 92 and 102 as with an air system. The pockets of air under pressure in chambers 110 and 117 serve to rapidly shift the diaphragms to the left when the water jets 32 and 42 are obstructed. Spring means could be placed in chambers 110 and 117 instead of using air pressure biasing.

A water pressure sensing system is particularly advantageous in sensing the edge of a wire or other web in a paper making machine where there are large amounts of water present in any event. In either an air pressure or water pressure sensing system where such water is present at the sensing location, it is prefer-red that a raised boss surround each jet so that such water will tend to flow away from the jet orifices rather than accumulating at such orifices and interfering with the jets.

Where the illustrated triple jet nozzle is used without change in a water actuated system, source 60 could be a city water supply and components 67, and 81-85 would be of suitable construction for water, but the system would otherwise be substantially the same. Bosses would preferably be used around the jets in a triple jet water system under the conditions described above where substantial amounts of water are present in the vicinity of the sensing head.

It is found that with the specific parameters given herein by way of example, in the illustrated system, all of the jets are of the discharging type thus preventing the entry of foreign matter into the ducts associated with sensing head. A strong signal is obtained from the diaphragm actuators with an extremely rapid reaction time of the order of 35 milliseconds.

The specific dimensions given herein a-re, of course, by Way of preferred example and not of limitation. it will be apparent that many modifications and variations may be effected without departing from the scope of the novel concepts of the present invention.

I claim as my invention:

1. An edge alignment control system comprising (a) an edge alignment control means for controlling the position of a moving web of material and capable of actuation in respective opposite senses to tend to move the web laterally in respective opposite directions,

(b) an edge position sensing head having fluid pressure output means for sensing edge position and generating first, second, third and fourth pressure outputs indicative of the position of the edge of the moving web, the difference between the first pressure output and the second pressure output having one value when the web is in a cor-rect position and having a substantially different value when the web is offset from the correct position in one direction, the difference between the third pressure output and the fourth pressure output having one value when the web is in the correct position and having a substantially different value when the web is offset from the correct position in a direction opposite to said one direction,

(c) first and second fluid pressure responsive devices coupled to said fluid pressure output means of said head and responsive to said first and second pressure outputs, and to said third and fourth pressure outputs, respectively, to provi e respective first and second mechanical outputs,

(d) first and second mechanically actuated switching devices coupled respectively to said first and second fluid pressure responsive devices and actuated respectively by said first and second mechanical outputs therefrom,

(e) electrically actuated means comprising said first and second mechanically actuated switching devices coupled to said edge alignment control means for movement thereof in respective opposite directions in response to said first and second mechanical outputs to tend to maintain said web in said correct position as defined by said head,

(f) said first fiuid pressure responsive device comprising a first diaphragm actuating means having respective actuating chambers referenced to the first and second pressure outputs, respectively; said seco-nd fluid pressure responsive device comprising a second diaphragm actuating means having respective actuating chambers referenced to the third and fourth pressure outputs, respectively; said first and second uid pressure responsive devices having mechanical output means providing the respective first and second mechanical outputs; and said first and second mechanically actuated switching devices comprising electric switches actuated by output displacements of said mechanical output means of lapproximately 1&2 inch; and

(g) first and second mechanical amplifiers connecting said first and second fiuid pressure responsive devices `to respective ones of said first and second mechanically actuated switching devices and mechanically arranged to actuate said first and second switching devices between open and closed positions with substantially no overtravel.

2. An edge alignment control system including:

(a) an edge alignment cont-rol means for controlling the position of a moving web and capable of actuation in respective opposite senses to move the web laterally in respective opposite directions;

(b) a sensing head held in a fixed spaced relation with respect to the edge of the moving web to develop respective first, second, third and fourth pressure outputs indicative of the position of the edge of the moving web;

(c) a first fiuid pressure responsive device connected to said first and second pressure outputs to be actuated in response to pressure between said first and second pressure variations outputs;

(d) a second iiuid pressure responsive device connected to said third and fourth pressure outputs to be actuated in response to pressure variations between said third and fourth pressure outputs;

(e) first and second switches connected to said edge alignment control means for controlling the direction of movement of said control means in response to the actuation of one of said Switches; and

(f) first and second mechanical amplifiers connecting said first and second fiuid pressure -responsive devices to a respective one of said switches and mechanically arranged to actuate said first and second switches between open and closed positions with substantially no overtravel.

3. A system for controlling the lateral position of the edge of a moving web including:

(a) a sensing head held in a fixed spaced relation with respect to the edge of the moving web to develop respective first, second, third and fourth pressure outputs indicative of the position of the edge of the moving web',

(b) a first fluid pressure responsive device connected to said first and second pressure outputs to develop a first mechanical output in response to pressure variations between said first and second pressure outputs;

7 (c) a second uid pressure responsive device connected of approximately 1/32 inch and with substantially no to said third and fourth pressure outputs to develop OVellaVeL a second mechanical output in response to pressure References Cited by the Examiner variations between said third and fourth pressure t t 5 UNITED STATES PATENTS ou pu s;

2,793,441 5/1957 Frenk 33-172 (d) rst and second switches; -and 2,794,444 6/1957 Markey- (e) first and second mechanical amphers engagmg 2,900,468 8/1959 Joy 20G-61.13 X

aid thrst arfid seicond swtitlcihtes respectively for atll- 10 FOREIGN PATENTS lon ereo an connec e o a respec ive one o e rst and second mechanical outputs of said first and 1'008106 5/1957 Germany' second Huid pressure responsive devices to actuate LOUIS R PRINCE, Primary Examneh said switches in response to a mechanical movement F. H. THOMSON, Assistant Examiner.

Claims (1)

1. AN EDGE ALIGNMENT CONTROL SYSTEM COMPRISING (A) AN EDGE ALIGNMENT CONTROL MEANS FOR CONTROLLING THE POSITION OF A MOVING WEB OF MATERIAL AND CAPABLE OF ACTUATION IN RESPECTIVE OPPOSITE SENSES TO TEND TO MOVE THE WEB LATERALLY IN RESPECTIVE OPPOSITE DIRECTIONS, (B) AN EDGE POSITION SENSING HEAD HAVING FLUID PRESSURE OUTPUT MEANS FOR SENSING EDGE POSITION AND GENERATING FIRST, SECOND, THIRD AND FOURTH PRESSURE OUTPUTS INDICATIVE OF THE POSITION OF THE EDGE OF THE MOVING WEB, THE DIFFERENCE BETWEEN THE FIRST PRESSURE OUTPUT AND THE SECOND PRESSURE OUTPUT HAVING ONE VALUE WHEN THE WEB IS IN A CORRECT POSITION AND HAVING A SUBSTANTIALLY DIFFERENT VALUE WHEN THE WEB IS OFFSET FROM THE CORRECT POSITION IN ONE DIRECTION, THE DIFFERENCE BETWEEN THE THIRD PRESSURE OUTPUT AND THE FOURTH PRESSURE OUTPUT HAVING ONE VALUE WHEN THE WEB IS IN THE CORRECT POSITION AND HAVING A SUBSTANTIALLY DIFFERENT VALUE WHEN THE WEB IS OFFSET FROM THE CORRECT POSITION IN A DIRECTION OPPOSITE TO SAID ONE DIRECTION, (C) FIRST AND SECOND FLUID PRESSURE RESPONSIVE DEVICES COUPLED TO SAID FLUID PRESSURE OUTPUT MEANS OF SAID HEAD AND RESPONSIVE TO SAID FIRST AND SECOND PRESSURE OUTPUTS, AND TO SAID THIRD AND FOURTH PRESSURE OUTPUTS, RESPECTIVELY, TO PROVIDE RESPECTIVE FIRST AND SECOND MECHANICAL OUTPUTS, (D) FIRST AND SECOND MECHANICALLY ACTUATED SWITCHING DEVICES COUPLED RESPECTIVELY TO SAID FIRST AND SECOND FLUID PRESSURE RESPONSIVE DEVICES AND ACTUATED RESPECTIVELY BY SAID FIRST AND SECOND MECHANICAL OUTPUTS THEREFROM,

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