US3343459A

US3343459A - Control system

Info

Publication number: US3343459A
Application number: US414608A
Authority: US
Inventors: Paul W Jacobsen
Original assignee: HG Weber and Co Inc
Current assignee: HG Weber and Co Inc
Priority date: 1964-11-30
Filing date: 1964-11-30
Publication date: 1967-09-26
Anticipated expiration: 1984-09-26

Description

Sept. 26, 1967 Filed Nov. 30, 1964 P. W. JACOBSEN CONTROL SYSTEM 513 so 78 45W w w 5 3 54 55 4 Sheets-Sheet l INVENTOR. 404 W JICOfif v M M W, a VMTTORNEY p 1967 P. w. JACOBSEN 3,343,459

CONTROL SYSTEM Filed Nov. 30, 1964 4 Sheets-Sheet 2 E D65- COKECTION DE VICE INVENTOR.

IDAUL W JAIL 0555M ZM y ATTORNEYS P 1967 P. w. JACOBSEN 3,343,459

CONTROL SYSTEM Filed Nov. 30, 1964 4 Sheets-Sheet 5 QQQQQQLJ AJQQQQQ cl N INVENTOR P404 M/J4CO55 V ATTORNEY Sept. 26, 1967 3,343,459

P. W. JACOBSEN CONTROL SYSTEM Filed Nov. 50, 1964 4 Sheets-Sheet 4 INVENTOR 544% h/ M46655! AT ORNEYS United States Patent 3,343,459 CONTROL SYSTEM Paul W. Jacobsen, Kiel, Wis., assignor to H. G. Weber and Company, Inc., Kiel, Wis., a corporation of Wisconsin Filed Nov. 30, 1964, Ser. No. 414,608 3 Claims. (Cl. 91-3) This is a continuation-in-part of my co-pending application Ser. No. 400,506, filed Sept. 30, 1964.

This invention relates generally to a web position control system and particularly to an edge alignment control system having an improved fluid actuated force amplifier for driving an edge position correcting device and more particularly to an improvement on the edge alignment control system illustrated in said co-pending application.

It is an object of the present invention to provide an improved fluid actuated force amplifier capable of controlling a web position correcting device in response to a mechanical input signal from a web position sensing head.

It is also an object of the present invention to provide an improved fluid actuated force amplifier having a gradual acceleration and/or deceleration characteristic as compared to existing devices.

It is another object of the present invention to provide an edge alignment control system which will control the edge of a web while at the same time having a minimum number of components and a high degree of reliability.

It is another object of the present invention to provide an edge alignment control system which will avoid electrical components so as to be particularly advantageous for use in areas where there is danger of explosion and the like.

It is another object of the present invention to provide an edge alignment control system with fluid pressure actuating means having uniform acceleration and deceleration control to eliminate jerking and hunting during the control of a web.

Another object of the present invention is to provide an improved fluid actuated force amplifier which can be operated using a city water supply as the hydraulic medi- A further object of the present invention is to provide a novel force amplifier having a vibration or dithering effect in the output thereof to overcome the static frictional forces of a web roll stand or the like to be actuated by said amplifier.

Still another object of this invention is to provide a simple and highly accurate means to control the acceleration and deceleration of a fluid actuated force amplifier so that such amplifier can be used to control or maintain the desired position of a large mass such as a web roll stand assembly.

Still another object of the present invention is to provide a jog control which will actuate a force amplifier for movement over a large distance.

A still further object of the present invention is to provide fine and coarse adjustment of a force amplifier, the fine adjustment being used to actuate the force amplifier for movement over a short distance and the coarse adjustment being used to actuate the force amplifier for movement over a long distance.

Other objects, features and advantages of the present invention will be apparent from the following detailed description taken in conjunction with the accompanying drawings, in which:

FIGURE 1 is a sectional view of a fluid actuated force amplifier and shows the acceleration and deceleration control means in accordance with the present invention;

FIGURE 2 is a somewhat diagrammatic view of an edge alignment control system and incorporates the im- 3,343,459 Patented Sept. 26, 1967 "ice provements of the fluid actuated force amplifier shown in FIGURE 1;

FIGURE 3 shows an alternate means for controlling the fluid actuated force amplifier shown in FIGURE 1;

FIGURE 4 is a detailed view showing internal parts of a preferred hydraulically actuated force amplifier in accordance with the present invention; and

FIGURE 5 is a somewhat diagrammatic illustration of an actuating arm which has movable diaphragms connected thereto to provide fine and coarse adjustment to the fluid actuated force amplifier of FIGURE 1.

The force amplifier shown in FIGURE 1 is designated by reference numeral 10, and has a body portion designated generally by reference numeral 11 and a piston generally designated by a reference numeral 12, which is axially movable in the body 11. The piston 12 has a piston head 15 circumferentially engaged by a seal 16, thereby preventing leakage of fluid between the piston head 15 and the cylinder wall 18 of the body '11. The piston 12 also has a piston rod portion 20 extending through the end wall 21 of the body 11. A seal 25, fixedly positioned by a recessed portion 26, is circumferentially engaged with the piston rod portion 20, thereby preventing the leakage of fluid between the piston rod portion 20 and the end wall 21.

The piston face 29 of the piston 12, the end wall 30 of the body 11 and the cylinder wall 18 define a control chamber 32 which will cause the position of the piston 12 to vary in response to changes in fluid pressure in the control chamber 32. The piston face 33 of the piston 12, the end wall 21, the cylinder wall '18 of the body 11 and peripheral surface 34 of the piston rod 20 define a high pressure chamber 37. By way of example, the piston face 29 may have twice the surface area 0 fthe piston face 33 so that equilibrium of the piston 12 is obtained when the fluid pressure in the chamber 37 is twice that of the fluid pressure in the chamber 32.

The term fluid pressure is used as generic to gases under pressure and liquids under pressure.

Passing through the end wall 30 is a movable control rod 40 having circumferentially engaged therewith a seal 41 fixedly positioned by a recessed portion 42 in the body 11. A valve member 43, which has a circumferential seat portion 44 and an extended tapered portion 45, is connected to the control rod 40 and movable therewith.

As the valve member 43 is moved in the outward direction (with spring maintaining outer shoulder 78 substantially engaged with seat 79) the seat portion 44 will disengage from the inner seat member 47 of the valve member 48 and the extended tapered portion 45 together with the inner seat member 47 will determine the cross-sectional area of the orifice 50. The area of orifice 50 is increased in proportion to the distance the valve member 43 is moved away from the valve member 48. As the valve member 43 is moved in the outward direction, the orifice 50 will continue to increase in cross section area allowing the fluid in the chamber 32 to pass through the orifice 50 with the rate of increasing flow being determined by the angle of taper of the tapered portion 45. The acceleration of the piston 12, in the direction of the arrow 51, will continue as the cross section area of the orifice 51 increases. As the pressure in the chamber 32 continues to decrease by bleeding oil through the orifice 5i) and therefrom through the bore 53 and a plurality of vents 5457 into a secondary relief chamber 60, the piston 12 and the valve member 48 will move in the direction of the arrow 61 until the inner seat 47 of the valve member 48 and the seat portion 44 of the valve member 43 are substantially engaged and the equilibrium condition of the pressures in the chambers 32 and 37 is again established.

As the piston 12 moves in the direction of arrow 6 the valve member 48 therein also moves in the direction 61 thereby gradually decreasing the cross-section area of the orifice 50 at a predetermined rate until the orifice 50 is substantially completely closed, preventing further decrease in pressure in the chamber 32. This feature of controlled deceleration is of prime importance in moving a large mass toward a desired end point. The mass, upon approaching the desired end point, begins to decelerate, thereby decreasing the momentum thereof so that overrun is substantially completely eliminated.

The fluid pressure which has escaped from the chamber 32, through the orifice 50, bore 53, and vents 5457 and into the secondary relief chamber 60 is released into a suitable drain or reservoir (not shown) through the port 64 in the piston rod portion 20 of the piston 12. However, should the power amplifier 10 be used in a high pressure air system a suitable port in the secondary relief chamber 60 is used to vent the chamber to atmosphere. The bracket 67 is used to secure the piston rod 20 to the edge correction device 66, and the mounting flanges 68 and 69 (FIGURE 2) are used to secure the body portion 11 in a fixed position relative to the movable mass. When the control rod 40 is moved inward, in the direction 51, the seat 44 and the inner seat 47 will remain engaged and no pressure in the chamber 32 will escape through the orifice 50. However, the valve member 48, which is urged in the direction 61 by a spring 70, is moved in the direction 51. The valve member 48 operates in a chamber 73 and is circumferentially engaged by a seal 74 fixedly located in the piston 12 by the recess portion 75. The fluid pressure in the chamber 73 is prevented from escaping to the chamber 60 by the seal 74. When the valve member 48 is moved in the direction 51 a shoulder 78 of the valve member 48 disengages from the seat portion 79 of the piston 12 and the cross sectional area of an orifice 80 is progressively increased at a rate determined by the tapered portion 83 of the valve member 48. The high pressure in the chamber 37 will pass through the lateral port 85 into the chamber 73 and therefrom through the orifice 80 into the controlled pressure chamber 32, thereby allowing the piston 12 to be moved in the direction 51 until the seat portion 79 of the piston 12 and the shoulder 78 of the valve member 48 are circumferentially engaged and equilibrium between the pressures in chambers'32 and 37 is once again established. Thus the acceleration and decleration of the piston 12 is proportional to the distance the valve member 48 is moved away from the seat 79 and to the angle of the tapered portion 83, which by way of example may be about two degrees. The portion 45 may also have a taper of about two degrees.

An inlet 86 in the body 11 is functionally arranged to receive a supply of water from a city water supply which by way of example and not by way of limitation provide a water pressure of 40 pounds per square inch to maintain the high pressure chamber 37 at a constant pressure of 40 psi. (gauge). An adjusting screw 88 having a recess 89 to receive a portion of the spring 70 is used to adjust the tension of the spring 70 thereby increasing or decreasing the force applied to the poppet valve 48 which urges it in the direction 61. Also, the adjusting screw 88 can be considered a sensitivity control for the control rod 40 as it is moved in the direction 51.

In FIGURE 2 the force amplifier 10 is shown having a water supply line 92 and a control diaphragm assembly 93 connected thereto. The control diaphragm assembly 93' is mounted on a bracket 94 by a fastener 95. A support 100, which has a slot 101 therein to guide a lever arm 102, and a support 103, which has a pivot point 105 for the lever arm 102, are used to maintain the diaphragm assembly 93 in a fixed position relative to the control rod 40. A diaphragm output rod 107 is coupled to diaphragm 93a and is pivotally connected to the lever arm the lever arm.

The water supply line 92 is connected to the water supply 110 to maintain a constant predetermined pressure in the high pressure chamber 37, FIGURE 1. A high pressure air supply from the line 111 is applied to a pressure regulator 112 through a line 113 and to a pressure regulator 114 through a line 115. The metering orifices 118 and 119 are so proportioned that the output static pressure thereof is maintained at a predetermined level in the

lines

121 and 122. The pressure in the line 122 is applied to ,a plurality of orifices 125 in the sensing head 126. The edge of a movable Web, shown as 128, 'is spaci-ally positioned in the opening of the sensing head 126, thereby blocking a portion of the orifices 125. A plurality of orifices 131 is geometrically opposed to the plurality of orifices 125 to receive a stream of moderately high pressure air from the orifice 125. The static pressure in the line 121 is therefore proportional to the number of orifices 125 and 131 which are unobstructed by the edge of the movable web 128, and therefore the pilot control rod 107 of the control diaphragm 93 is moved by the change in static pressure in the line 121.

In operation, if the edge of the web 128 is located in the opening 130 of the sensing head 126 so as to obstruct a predetermined number of orifices 125 and 131, the control rod 40 will be maintained substantially in the equilibrium position illustrated in FIGURE 4. In this condition the entire control system is said to be in a state of equilibrium. If the edge of the web 128 is moved in the opening 130 relative to the position of the sensing head 126 in the direction of arrow 136 so as to decrease the number of orifices which are obstructed by the Web 128, more of the orifices 125 will have the jets therefrom impinging on the corresponding aligned orifices 131 and the resulting increase in the static pressure in the line 121 will move the pilot control rod 107 to the right as viewed in FIGURE 2. The control rod 40 also moves to the right but the distance it moves is proportional to the ratio of the lever arm 102. As the control rod 40 moves to the right the valve member 43, FIGURE 1, will move the valve element 48 in the direction of arrow 51 thereby allowing the fluid pressure in chamber 37 to pass through the port 85, the primary relief chamber 73 and the orifice 80' into the control chamber 32 and move the piston rod 20 in the direction of arrow 51. This action will move a suitable web alignment roller or roll stand assembly represented by component 66 in FIGURE 2 so as to tend to return the edge of the web 128 to the desired neutral position in the opening 130.

If the edge of the web 128 is moved in the direction of arrow 135 in FIGURE 2 so as to increase the number of orifices 125 and 131 which are obstructed, the static pressure in the line 121 is decreased. This decreased pressure in the line 121 will cause the pilot control rod 107 to move to the left moving the control rod 40 in the same direction. This action will cause the valve member 43 to move in the direction of arrow 61, FIGURE 1, thereby progressively opening the orifice 50 and allowing the fluid pressure in the control chamber 32 to escape therethrough into the relief chamber 60 and therefrom to a drain or reservoir through the relief port 64. The pressure in the chamber 37 will then move the piston 12 in the direction of arrow 61 at a predetermined rate, thereby moving device 66 so as to tend to return the edge of the web 128 to the predetermined neutral position in the opening 130 of the sensing head 126.

By incorporating the features of the present invention, the gradual acceleration and deceleration of movement of a large mass such as a web roll stand or the like can be accomplished. 7

FIGURE 3 shows a modified arrangement of the force amplifier 10 shown in FIGURE 2. The control diaphragm assembly 93 is so positioned as to directly couple the control rod 40 to the output thereof, thereby obtaining a proportional movement of the control rod 40 with the movement of the output of the control diaphragm 93.

An alternate means of biasing the valve member 48 in the direction of the seat 79 is shown in the detailed view of FIGURE 4. The biasing means in FIGURE 4 is located between the collar portion 138 and the seal 75, in the relief chamber 73, and comprises a compression spring 140. The spring 140 maintains the outer seat 78 of the valve member 48 engaged with the seat portion 79. However, when the valve member 43 is moved in the direction of arrow 51 the force of the biasing spring 140 is overcome and the seat 78 is disengaged from the seat 79, thereby opening the orifice 80. When the valve member 43 is moved in the direction of arrow 61 the seat 44 is disengaged from the inner seat 47, thereby opening orifice 50.

Joining the control rod 40 to the valve member 43 is a shaft 141. The shaft 141 is secured to rod 40 and member 43 by

set screws

142 and 143. Three equally spaced guide members such as diagrammatically indicated at 145, 146 and 147 maintain the control rod 40 in axial alignment in the opening of the piston 12.

Control of acceleration and deceleration can be obtained by selecting the angle of the taper of surfaces 45 and 83. By way of example, and not by limitation, the present invention utilizes a taper of two degrees on both the tapered portions 45 and 83.

With a system such as specifically illustrated in FIG- URE 4 and wtih a forty pound per square inch (gauge) water supply, it was found that the unit showed excellent acceleration and deceleration characteristics with no measurable jumpiness when actuating an edge alignment roller. It appears that static friction in the load is being overcome by a high frequency very small amplitude oscillation of the piston 12 in the equilibrium condition. It is believed that this dithering action is caused by minute leakages at the orifices 50 and 80. The water, being noncompressible apparently is alternately opening and closing orifices 50 and 80 at high frequency. At the same time the load of the force amplifier is effectively locked in the desired position so that liquid operation provides a much more desirable actuator for large masses than a comparable actuator utilizing a gas actuating medium.

Shown in FIGURE 5 is a preferred embodiment of a control system having fine and coarse adjustment controls which are used to actuate the control rod 40 for movement of the piston rod over a relatively short distance and for movement of the piston rod 20 over a longer distance. The force amplifier 10 is provided with a rear housing 150 having an extended portion 151. A lever arm 154 is pivotally connected to the extended portion 151 of housing 150 by a pin 155. The control rod 40 has a hooked end portion 156 which is carried in an elongated slot 157, and which slot is in a lower portion 158 of lever arm 154 below pin 155. Also connected to the extended portion 151 of housing 150 is an L-shaped mounting bracket 160. Secured to the mounting bracket 160, by bolts 161 and 162, is a diaphragm actuating means 164 to provide fine actuating movement of lever arm 154 which, in turn, will move the control rod 40 to actuate the force amplifier 10. Another diaphragm actuating means 165 is secured to a bracket 160 by

bolts

166 and 167 to provide coarse or jog actuating movement of lever arm 154.

Located in the diaphragm actuating means 164 is a resilient diaphragm 168. The periphery of the diaphragm 168 is secured between body members 169 and 170, while the center of diaphragm 168 is secured between washers 173 and 174. A push rod 175, which extends through an opening 176 in bracket 160, is connected to the center portion of the washers 173, 174 and diaphragm 168 and is held in place by a nut 176. A spring 177 is placed about a portion of a push rod 175 within diaphragm actuating means 164 to bias the diaphragm 168 toward the body member 170.

Push rod is connected to the lever arm 154 by means of a pair of pre-loaded springs 178 and 179. Spring 178 is compressed between retaining

washers

180 and 181, which

washers

180 and 181 are held in place by retaining

collars

182 and 183, respectively. Spring 179 is compressed between retaining Washers 185 and 186, which washers 185 and 186 are held in place by retaining collars 187 and 188, respectively. Push rod 175 passes through an aperture 189 in the lever arm 154 and is resiliently held relative to lever 154 by the opposing forces of springs 178 and 179. The opposing forces applied to the lever arm by springs 178 and 179 are greater than the force required to actuate the control rod 40. Therefore, the lever arm 154 will not move relative to the push rod 175 when a corrective movement is applied to the push rod by diaphragm 168. This corrective movement will be transmitted directly to a major length portion 190 of lever arm 154 above pin 155. The resultant movement about pivot point 155 of the minor length portion 158 of lever arm 154 causes movement of the control rod 40.

The diaphragm actuating means 165 has a diaphragm 192 connected to the major length portion 190 of lever arm 154 by means of a push rod 193. An elongated slot 194 in the arm 154 is provided to carry a hook portion 195 of the push rod 193. The push rod 193 passes through an aperture 196 and a seal 197 and is connected to the center of diaphragm 192 by washers 198, 199 and

nuts

200, 201. By way of example and not by Way of limitation, the seal 197 may be relatively loose about push rod 193 thereby affording only a slight frictional resistance to the movement of the push rod. The periphery of diaphragm 192 is secured between body members 202 and 203.

The force applied to lever arm 154 by push rod 193 is substantially greater than the opposing forces applied to the lever arm by springs 178 and 179. This will cause relative movement between the lever arm 154 and push rod 175. Therefore, the movement of push rod 193 is transmitted to the control rod 40 and onlya slight amount of the force due to the jog movement of diaphragm 192 is applied to diaphragm 168, thereby effecting only a slight change of position of diaphragm 168. The forces exerted on diaphragm 168 by the static pressure and by spring 177 are greater than the forces applied thereto by the push rod 175 when either the spring 178 or the spring 179 is depressed, thereby maintaining the diaphragm 168 substantially stationary as the lever arm 154 is moved by diaphragm 192.

Diaphragm actuating means 165 has two

chambers

205 and 206 which are connected to an auxiliary correction control system 207 through

lines

208 and 209 respectively. The control system 207 will apply a greater fluid pressure to chamber 205 and a lesser fluid pressure to chamber 206 to shift the diaphragm 192 in the direction indicated by the dotted line. To shift the diaphragm 192 in the other direction the fluid pressure applied to chamber 2126 is greater than the fluid pressure applied to chamber 205. The diaphragm actuating means 164 has a chamber 210 which is vented through an opening 211 to atmospheric pressure. The actuating means 164 has a chamber 215 which has a static fluid pressure from a line 216 applied thereto. The fluid operated sensing nozzle 126 has one side connected to the line 216 by a line 219, and the other side of the nozle is connected between two

pressure regulators

220, 221 through a line 222 and a metering orifice 223. The regulator 220 is also connected to the line 216 through a metering orifice 225. The regulator 221 is connected to a source of air under pressure through a line 226. As mentioned hereinabove, the static pressure in line 216 will vary depending upon the position of the edge of the web 128 in the opening 130 of the sensing nozzle 126. The desired position of the edge of the moving web 128 may be midway in the opening 130 so as to obstruct half of the orifices 125 and 131 while allowing the other half of the orifices 125 to create a predetermined static pressure in line 216 corresponding to a neutral position of the moving web 128.

Summary of operation With the needle-like valve member 43 firmly seated against the inner seat portion 47 of the tubular valve member 48 and with the'valve member 48 firmly seated against the seat portion79 of the piston 12, and with the force on the piston face 29 in chamber 32 equal to the force on the piston face 33 in chamber 37, FIGURE 1, the force amplifier is in a state of equilibrium. When the valve member 43 is moved in the direction of arrow 61 and the seat portion 44 thereof is disengaged from the inner seat portion 47 of the valve member 48, the fluid pressure in the chamber 32 will escape through the orifice 50 and therefrom through the relief chamber 60 to a suitable drain or reservoir through the port 64, and the piston 12 will move in the direction 61. However, the portion 45 of the needle valve member 43 is tapered so as to control the rate of change of the cross-sectional area of the orifice 50 thereby providing controlled gradual acceleration of the movement of the piston 12. As the piston 12 approaches the desired end point, the orifice 50 gradually decreases in size at the same controlled rate, which is determined by the angle of the tapered portion 45. The deceleration of the piston 12 continues until the seat portion 47 of the valve member 48 and the seat portion 44 of the needle valve member 43 are circumferentially engaged and the force on the piston face 29 is substantially equal to the force on the piston face 33.

When the control rod 40 is moved in the direction 51 the needle valve member 43, which is abutted with the valve member 48, will move the valve member 48 in the direction 51 thereby disengaging the outer seat portion 78 of the valve member 48 from the seat portion 79 of the piston 12. This action will cause the high pressure in the chamber 37 to pass through the port 85, the chamber 73 and the orifice 80 into the control chamber 32 so that the piston 12 is moved in the direction 51. The portion 83 of the valve member 48 is tapered so as to gradually increase the cross section area of the orifice 80 thereby obtaining acceleration control of the piston 12 while moving in the direction 51. As the piston 12 approaches the desired end point, the seating portion 79 will approach the seat portion 78 of the valve member 48, and will gradually decelerate at a controlled rate until the Seat portion 79 and the seat portion 78 are circumferentially engaged and the force on the face 33 is substantially equal to the force on the face 29, again placing the force amplifier 10 in a condition of equilibrium. A sensitivity control for the control rod 40, when moving in the direction 51, is obtained by adjusting screw 88 which controls the tension of the spring 70.

In the edge alignment control system shown in FIG- URE 3, the force amplifier 10 is supplied with water, at city pressure, through line 92, which is the primary actu- "ating force of the force amplifier 10. As the control rod 40- is moved in either direction, by the control diaphragm 93a, the piston 12 of the force amplifier 10 will also move in the same direction but with an increased force. Therefore, the position of the piston 12 is determined by the location of the control rod 40 which in turn is positioned by the control diaphragm assembly 93 which senses the static pressure in the line 121. The static pressure in the line 121 will vary depending upon the position of the edge of the web 128 in the opening 130 of the sensing head 126. By way of example, the desired position of the edge of the web 128 may be midway in the opening 130 so as to obstruct half of the orifices 125 and 131 while allowing the other half of the orifices 125 to create a predetermined static pressure in the line 121 corresponding to a neutral position of control rod 40.

If the edge of the web 128 is moved in the direction 136 to decrease the number of orifices 125 and 131 obstructed, the static pressure in the line 12 1 will increase 7 and the control rod 40 will move in the direction 136,

which in turn will move the piston 12 in the direction 136 to position the edge correction device 66 to tend to move the edge of the web 128 in the direction 135.

If the edge of the web 128 is moved in the direction 135 from its neutral position thereby increasing the number of orifices 125 and 131 obstructed, the static pressure in the line 121 will decrease which in turn will move the control rod 40 in the direction 135. This action will cause the piston 12 of the force amplifier 10 to move in the direction 135, thereby actuating the edge correction device 66 to tend to reposition the edge of the web 128 1 in the direction 136.

A detailed view showing the construction of the relief chamber 73, the needle valve member 43 and the valve member 48 is shown in FIGURE 4. Also shown in FIG- URE 4 is an alternate arrangement for the biasing of the valve member 43. A spring 140 which is in the relief :chamber 73 and is under compression between the collar 138 and the seal 75, is used to urge the valve member-43 toward the seat 79. When the force amplifier is activated 7 by hydraulic liquid, an oscillatory condition is believed to the diaphragm 168 to be shifted accordingly. The shifting of diaphragm 168 is transmitted to the lever arm 154 by the movement of push rod 175, and which movement is indicative of the position of the edge of the web 128. The springs 178 and 179 are secured to the push rod 175 under compression thereby applying opposing forces from the push rod 175 to the lever arm 154' in such a manner as to effect a somewhat rigid connection between the lever arm and push rod. The force required to actuate the control rod 40 is substantially less than the opposing force applied to the lever arm by springs 178 and 179. Therefore, there will be no relative movement between the lever arm 154 and push rod 175 when the push rod is moved back and forth by diaphragm 168.

However, should it be come necessary to move the piston rod 20 faster or over a longer distance, a jog signal from the auxiliary correction control system 207 is supplied to diaphragm actuating means to move the push rod 193 which, in turn, will move the control rod 40 further into or out of the force amplifier 10. As the lever arm 154 is moved by push rod 193 there will be relative movement between the lever arm and push rod 175, and only a small amount of the movement of the arm will be transmitted to the diaphragm 168.

Referring to FIGURE 4, if it is assumed that maximum deflection of push rod leads to positions of control rod 40 indicated in dash outline at 40a and 40b in FIG- URE 4, then jog deflection of push rod 193 is arranged to produce a substantially greater displacement of control rod 40 to positions as indicated in dotted outline at 40c and 40d. Thus the acceleration of movement of the edge correction device 66, FIGURE 2, is of a substantially different order for jog operation than for normal edge alignment.

Jog operation may be desirable during start up of a new Web, for example, where there is a very substantial error in edge position which should be corrected rapidly. The jog operation may be initiated manually in the desired direction by means of momentary

electric switch

240 or 241. Manual actuation of switch 240 may energize a solenoid valve of component 207 in a direction to supply air pressure to line 209 while connecting line 208 to atmosphere. Conversely, manual actuation of switch 141.

may actuate the solenoid valve in a direction to apply pressure to line 208 and connect line 209 to atmosphere.

Switches

240 and 241 may be of the type which are continuously urged to open position and thus open the electric circuit whenever manual actuating pressure is removed therefrom to shift the solenoid valve to a neutral position where both

lines

208 and 209 are connected to atmosphere.

Referring to FIGURE 4, it will be observed that control rod 40 has a first relatively sharply angled seating face 44 and a second relatively gently sloping control face 45. Similarly, the valve member 48 has a first relatively sharply angled seating face 78 and a second relatively gently sloping control face 83.

It will be understood that modifications and variations may be efiected without departing from the spirit and scope of the novel concepts of this invention.

I claim as my invention:

1. An edge alignment control system comprising:

a sensing head having fluid pressure means for sensing edge position and for generating changes of static pressure in response to errors in the position of the edge,

first diaphragm means for actuation in response to said changes of static pressure from said sensing head,

second diaphragm means for actuation in response to a jog signal to move an edge alignment correction device over a relatively long distance,

a force amplifier actuated by said first and second diaphragm means and having an output element for controlling the edge alignment correction device,

valve means in said force amplifier for controlling the acceleration and deceleration of the movement of said output element,

said valve means comprising a pair of tapering elements each having a gradual taper to provide a gradual opening and closing of said valve means and each having a precipitous taper adjacent the larger diameter portion of said gradual taper to provide for closure of said valve means when said force amplifier is not actuated, and

means for supplying a liquid under pressure to said force amplifier for actuating said output element under the control of said valve means.

2. An edge alignment control system comprising:

diaphragm means for actuation in response to said changes of static pressure from said sensing head,

a force amplifier actuated by said diaphragm means and having an output element for controlling the edge alignment correction device,

said valve means comprising a pair of tapering elements each having a gradual taper to provide a gradual opening and closing of said valve means and each having a precipitous taper adjacent the larger diameter portion of said gradual taper to provide for closure of said valve means when said force amplifier is not actuated,

a jog control system consisting of an auxiliary diaphragm means for actuation in response to a jog signal,

lever means connecting said diaphragm means and said auxiliary diaphragm means to a control rod of said force amplifier, and

means connected between said diaphragm means and said lever means to provide a rigid connection from said diaphragm means to said lever means when said lever means is moved by said diaphragm means and to provide a flexible connection from said diaphragm means to said lever means when said lever means is moved by said auxiliary diaphragm means.

3. An edge alignment control system comprising:

a sensing head having fluid pressure means for sensing edge position and for generating changes of static pressure in response to errors in the position of the edge;

diaphragm means for actuation in response to said change of static pressure from said sensing head;

a force amplifier having an output element for controlling an edge alignment correction device;

valve means in said force amplifier for controlling the acceleration and deceleration of the movement of said output element, said valve means comprising a pair of tapering elements each having a gradual taper to provide a gradual opening and closing of said valve means and each having a precipitous taper adjacent the larger diameter portion of said gradual taper to provide for closure of said valve means when said force amplifier is not aceuated;

a lever arm having one end thereof connected to a control rod of said force amplifier and the other end thereof connected to a push rod of said diaphragm means;

jog control means connected to said lever arm intermediate its two ends;

spring means connected to said push rod on each side of said lever arm to provide a rigid connection between said push rod and said lever arm when said lever arm is actuated by said diaphragm means and to provide a flexible connection between said push rod and said lever arm when said lever arm is actuated by said jog control means; and

OTHER REFERENCES Addison, Herbert: Applied Hydraulics, London, Chapman and Hall Ltd., 1964, pages 40-41.

MARTIN P. SCHWADRON, Primary Examiner.

P. T. COBRIN, B. L. ADAMS, Assistant Examiners.

Claims

1. AN EDGE ALIGNMENT CONTROL SYSTEM COMPRISING: A SENSING HEAD HAVING FLUID PRESSURE MEANS FOR SENSING EDGE POSITION AND FOR GENERATING CHANGES OF STATIC PRESSURE IN RESPONSE TO ERRORS IN THE POSITION OF THE EDGE, FIRST DIAPHRAGM MEANS FOR ACTUATION IN RESPONSE TO SAID CHANGES OF STATIC PRESSURE FROM SAID SENSING HEAD, SECOND DIAPHRAGM MEANS FOR ACTUATION IN RESPONSE TO A JOG SIGNAL TO MOVE AN EDGE ALIGNMENT CORRECTION DEVICE OVER A RELATIVELY LONG DISTANCE, A FORCE AMPLIFIER ACTUATED BY SAID FIRST AND SECOND DIAPHRAGM MEANS AND HAVING AN OUTPUT ELEMENT FOR CONTROLLING THE EDGE ALIGNMENT CORRECTION DEVICE, VALVE MEANS IN SAID FORCE AMPLIFIER FOR CONTROLLING THE ACCELERATION AND DECELERATION OF THE MOVEMENT OF SAID OUTPUT ELEMENT,