US 3289967 A
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Description (OCR text may contain errors)
Dec. 6, 1966 A. I. ROBINSON 3,289,957
TENSION REGULATOR Filed June 1, 1964 4 Sheets-Sheet 2 -Jill 34 30 2s ummiiii n. liiiummiiiiin-- Ii 13 if e w 70 y M V 62 3M 72 u as: 63
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HIS AGENT Dec. 6, 1966 A. ROBINSON TENS ION REGULATOR 4 Sheets-Sheet Filed June 1, 1964 @Q ow lwv y mm 3N mmm ART 1. ROBINSON INVENTOR.
9" Hi5 AGENT! Dec. 6, 1966 A. ROBINSON TENSION REGULATOR 4 Sheets-Sheet 4 Filed June 1, 1964 ART I. ROBINSQN INVENTOR.
24/ HIS AGENT Now United States Patent 3,289,967 TENSION REGULATOR Art I. Robinson, P.0. Box 606, Wichita Falls, Tex. Filed June 1, 1964, Ser. No. 371,605 5 Claims. (Cl. 242-7543) This invention relates to control means for the operation of a pneumatic circuit to regulate the tension in a moving web of sheet material, by controlling the brake friction on the unwinding roll of material.
The present invention is so designed as to furnish a simplified, yet sensitive and dependable pneumatic regulator which utilizes a fluid actuated motor, preferably an air brake, on an unwind roll to automatically vary the resistance to rotation of the unwind roll, in response to the tension of the sheet material being unwound from the roll.
In this device pneumatic valve means controls fluid communication between a source of fluid under pressure and a fluid operated motor. The first pneumatic valve means is controlled by a second pneumatic valve means, whereby output pressure is controlled by, and is proportional to, the tension of the sheet material which the fluid operated motor may control.
An object of this invention is to furnish a simplified, sensitive, and dependable pneumatically operated regulator for the tension of a moving web, which utilizes a fluid actuated motor and an air brake on a roll of sheet material to be unwound, to automatically vary the re-' sistance of the unwind roll to rotation in response to the tension on the sheet material being unwound from the roll.
An important object of this invention is to provide a second pneumatic valve means of a non-constant air bleed type, the output signal of which is automatically proportioned, at all times, to the tension of the sheet material.
Another object of the invention is to provide a first pneumatic valve means, of simplified construction, the output signal of which is multiplied and inverted from the change in the signal pressure received from the second pneumatic valve means, said output pressure of said first pneumatic valve means serving to operate the fluid motor to cause a change in resistance of rotation of the unwind roll, so as to restore the tension in the sheet material to the desired control point.
A further object of the invention is to additionally provide for manual control of the fluid operated motor, when such control is desirable, or is a matter of convenience to the operator.
Yet another object of the invention is to provide a second pneumatic valve means which is capable of continuously indicating, quantitatively, the amount of tension in the sheet material.
Another object of this invention is to provide control means for controlling the total tension in a moving web, which means is responsive to tension variations at either or both sides of the moving web.
Yet another object of the invention is to provide an improved means for controlling the tension of a moving web, where tension in the web may vary from one side to the other, by providing a mechanism which is operated by a compressed fluid, such as air.
Still another object of the invention is to provide a web tension control means whereby the total tension in themoving web is sensed through tension responsive roll means, which will maintain the tension responsive member in a predetermined plane at all times, regardless of the change in ambient temperature at either or both sides of the sensing roll, and regardless of the change of force "ice at either side of the roll, which results from a shift of tension in the web from one side to the other.
Yet another object of the invention is to provide a web tension control means, including measuring means, which will indicate the total tension existing in the moving web, even though thetension in the moving web varies continually from one side to the other.
Another object of the invention is to provide a pneumatic strain gauge which is operable with a minimum of friction and the stability of which has been established by prevention of the propagation of harmonic acoustical vibration caused by the overdriving of the valving mechanism.
'A further object of the invention is to provide a pneumatic strain gauge which is simple in construction, accurate in operation, and which is relatively low in the cost of manufacture.
A still further object of the invention is to provide a strain gauge with a flexible, resilient, frictionless strip hinge between a bearing support and a base to movably support a bearing.
A final object of the invention is to provide a pneumatic control to regulate the tension of a moving web winding onto a roll.
Other objects and advantages of this invention will become apparent to those skilled in the art, as the description proceeds, with the teachings of the principles of this invention in relation to the disclosure, claims and drawlngs.
Reference is now had to the accompanying drawings, in which like reference characters designate like parts in the several views thereof, in which:
FIG. 1 is essentially a diagrammatic view of a web tension regulator embodying the invention;
FIG. 2 is a detailed, enlarged, vertical sectional view taken on the line 2 2 of FIG. 3, looking in the direction indicated by the arrows;
FIG. 3 is a top plan view of the second valve means shown in FIG. 2 with portions broken away to show details of construction;
FIG.'3A is a sectional view taken on the line 3A3A I form of web tension regulator embodying the invention;
FIG. 5 is a perspective, schematic, fragmentary view, showing a web tensioning regulator and a motor driven, clutch controlled winding roll.
With more detailed reference to the drawing, particularly to FIG. 1 thereof, the numeral 10 designates a traveling web of material, such as sheet paper, fabric,
metal sheet, wire screen, plastic sheet, or the like, which web of material is traveling in the direction indicated by the arrow in FIG.) 1. The traveling web is unwound from unwind roll 12, which roll is supported by a shaft 13 which is controlled by braking vmechanism 14. The unwind roll 12 moves under'the periphery of first idler roll 16, over a second idler and tension responsive roller member 18, and finally under a last idler roll or first process roll 20.
The variation of braking forces in mechanism 14 will control the amount of tension on the web 10 as it is being pulled oil the unwind roll 12. Brake mechanism 14 is a commercial air brake, and is actuated by application of varying fluid pressure in conduit 22 to change the braking forces, by means of brake shoes forced against brake disc by fluid pressure, which pressure is confined in resilient chambers. Variations of fluid pressure in conduit 22 is determined by the first valve means, indicated generally at 24, and including valves 24m and 24k and diaphragms 35, 37 as will be described in detail hereinafter. The first valve means 24 is, in turn, controlled by tension responsive second valve means, designated generally at 26, as will be described in detail hereinafter. I
The second valve means 26 is operated by a tension responsive member 18, preferably in the form of a roll, over which roll the web passes in tension, thereby imparting a loading component to the roll, which is proportional to the tension in web 10. One end of the shaft of the tension responsive member 18 is mounted in a pillow block bearing, shown at 27, which is bolted to the platform 28 of the second valve means 26. Platform 28 is free to make significant vertical movement, by virtue of being hinged by the frictionless metal strip 30 which is clamped to the platform 28 and to the housing 32 by clamps 34 which are secured by a plurality of screws 36. Platform 28, while free to be directed vertically, is very rigid and resistant to horizontal force components, thereby forming a very satisfactory mount for the bearing 27 on one end of the tension responsive member 18. Vertical movement of platform 28, in actual operation, is minute, so that the actual flexing of the elastic strip 30 is such as to be well within the elastic and practical fatigue limits of the material.
The housing 32, preferably a casting, is constructed of two upright partitions 38, each of which is flanged at either end to form mounting feet, in which feet holes 40 are drilled (FIG. 2), for securing the housing, by bolts, to a suitable foundation. The partitions 38 are connected to a rectangular bed 42, in which bed a circular concavity 44 is formed, in which concavity is centered an adjustable valve and seat assembly, comprising a valve seat 46 which is threadably engaged with bed 42 so as to be in communication with concavity 44. The valve seat 46 is internally machined to form a bore of conical shape, which bore receives the large diameter end of a valve plug 48, which plug constitutes two parti-spheres which are fixed to a connecting pin to form a single, unitary member. Spring 50 supports the valve plug 48 upwardly in its normal position and rests on plug 52, which is threadably engaged to the bottom of the bore of the valve seat 46 to form a pressure tight seal. The valve seat 46 is provided with a locking ring 54, which locking ring is secured with a set screw 56, after the valve seat 46 is adjusted to the desired position. O-rings 58 provide a pressure seal around valve seat 46 on either side of a communicating port, which port is cross drilled through the tubular wall of valve seat 46 to receive a supply of compressed air from inlet conductor tube 60-. It is thus seen that compressed air, which enters the conductor tube 60 will be channeled to the bore of valve seat 46 and will act on valve plug 48 to force it into sealing engagement with the valve seat 46.
The concavity 44, above mentioned, is volume chamber 62, which is formed by a resilient diaphragm 64, which is closed at the outer periphery thereof by diaphragm ring 66 and at the inner periphery thereof by valve seat 68 which is screw threaded into'a circular diaphragm plate 70. The diaphragm ring 66 clamps the outer periphery of diaphragm 64 to form a pressure tight seal with the rectangular bed 42 by means of bolts 72 and nuts 74. Volume chamber 62 is connected to conductor tube 76. through drilled passageway 78; An inlet valve 61 and an outlet valve 63 are so positioned that any change in force applied to platform 28 will cause movement ofdiaphragm plate 70, and the unseating of inlet valve 61 or of outlet valve 63, either to admit air under pressure into volume chamber 62, from a source of air pressure, or to discharge air from volume chamber 62 through diaphragm plate 70 to atmosphere.
A volume bottle 75 is connected in fluid communication with conductor tube 76, which, together with adjustable orifice 77, maintains a substantially uniform change of pressure in conductor tube 76 by eliminating pressure surges.
Valve seat 68 has a conical bore therein, which receives the small diameter end of valve plug 48, said conical bore being connected with a drilled vent passageway which extends concentrically through the valve seat 68 and is in communication with cross drilled venting passageway 80 in the diaphragm plate 70.
Platform 28, which is secured at one end by the elastic strip 30, is free to move vertically between two safety limit stops at opposite ends thereof, the downward limit stop being that portion of the housing seen above the partition 38 and the upward limit stop being the head of safety screw 82 which is anchored in the same portion of the'housing above partition 38 that forms the before mentioned downward limit stop and extends through a drilled clearance hole in platform 28. In actual operation, movement of the platform 28 is not suflicient to contact either of the safety limit stops, the movement being minute and resulting in the platform 28 being returned to a neutral plane of force-pressure balance system, comprising the downward force due to the tension component, and the upward balancing force equal to the compressible fluid pressure in volume chamber 62 acting on the effective area of diaphragm 64. The free end of platform 28 is fastened to a pulsation dampening fluid piston dash pot, which constitutes a cylinder 84 which is secured to the feet of housing 32 by means of screw 86. A piston 88, which is within cylinder 84, which cylinder submerged in fluid, is sealed by flexible, resilient diaphragm 92 which is clamped by ring means 94 and screws 96. The connecting rod of piston 88 extends through diaphragm 92 and engages threaded adapter 98 to form a pressure seal. Adapter 98 is fastened in aligned relation with connecting rod 100, a nut 102 surrounds rod and threadably engages adapter 98 to pivotally mount a sphere 103 therein, which sphere is on the lower end of rod 100. The connecting rod 100 is fastened, through threaded engagement, to platform 28 and is locked into position by nut 104.
Platform 28, preferably a casting, has two similarly for-med rectangular projections 106 designed to form a T-slot for receiving the bolt heads which secure the pillow block bearing 27 which journals the shaft of idler roll, tension responsive member 18.
The first valve means 24, although well known in the art, will be described briefly, in order to amplify the present disclosure. The first valve means is indicated generally by the numeral 24 and includes valves 24m and 24k and diaphragms 35, 37, as best seen in FIG. 1. The variable control signal, such as the pressure signal in conductor tube 76, is induced into the first valve means 24 between two diaphragms 35 and 37 of dissimilar area which forms a first chamber 240, the top diaphragm 35 being of greater area and being opposed by an adjustable spring force. The diaphragms 35 and 37 are centrally apertured and are held in spaced apart relation by a longitudinal spacer 24i. The spacer 24i is longitudinally apertured and has a valve seat 24 fitted in the lower end of the aperture, which valve seat forms a fluid tight seal between apertured diaphragm 37 and the spacer 24i. An apertured member 24p surrounds the spacer 241' and is fitted in sealed relation with the upper apertured diaphragm 35 so that the first chamber 24a of valve means 24 is sealed against leakage around the diaphragms 35 and 37. Therefore, if there is pressure between these diaphragms, there will be a net upward force acting against the springs, and if the spring force is adjusted in equilibrium for a particular pressure, any increase in this pressure between the diaphragms will result in an unbalanced force which will compress the spring upward and move thev diaphragm assembly in that direction. At the bottom of the diaphragm assembly is a seat and valve arrangement having upper and lower valves 24m and 24k, respectively, located therein which will cause the modulated, or output pressure, from the first valve means 24 through conductor tube 108 to be vented from chamber 24a below diaphragm 37 and thereby decreased. Conversely, any decrease in pressure between the diaphragms 35 and 37 through conductor tube 76, below the equilibrium point of spring force, will allow the spring to expand downwardly and move the diaphragm assembly in that direction. The valve arrangement 24k, at the bottom of the diaphragm assembly will be opened, will now admit compressed air to the modulating chamber 24a, and the output pressure from the first valve means 24 through conductor tube 108 will be increased. It is therefore clear that the output pressure from the first valve means 24 through conductor tube 108 is inversely proportional to the input pressure through conductor tube 76. The magnitude of the differences in these pressures will be dependent upon the differences in the areas of the two diaphragms 35 and 37 in the first valve means 24. A bleed orifice 109 may be added in conductor tube 108, if desired, in order to improve the sensitivity.
Multi-lateral conductor tube 60 which is a standard commercial item, furnishes a source of compressed air through regulator 110 to the first valve means 24, the second valve means 26, and to a standard commercial booster relay 112. The purpose of the booster relay 112 is to further amplify the volume and pressure output from the first valve means 24. Output from the booster relay 112 is delivered through conductor tube 114 to multi-port selector valve 116, which can communicate with conductor tube 118 to deliver the compressed air to operate the fluid motor of braking mechanism 14.
Provision is made for optional manual control of braking mechanism 14 by reducing the primary compressed air supply pressure source which arrives in the branched conductor tube 128 by means of adjustable pressure reducing regulator 122. The desired output pressure can be selected, as observed on indicating pressure gauge 124, and delivered to the braking mechanism 14 through conductor tube 118 by proper movement of the selector valve 116. Other pressure gauges can be provided in the system, such as pressure gauge 126, which indicates the output pressure from the tension-sensing second valve means 26, which pressure is always directly proportional to the tension in the moving web 11) of sheet material, and which may be calibrated directly in terms of tension forces in web 10. An additional pressure gauge 128 is provided for ascertaining the output pressure of regulator 110, and pressure gauge 130 is provided to indicate the automatically controlled pressure output from booster relay 112. The selector valve 116 is also provided with a venting position, so as to vent all fluid pressure from braking mechanism 14, when desired.
As an example of operation, when the tension in web 11 increases beyond the set control point, an additional force will be transmitted through the tension responsive member 18 onto the platform 28 of the second valve means 26. The plateform 28, having no resistance to vertical force components due to free pivoting permitted by elastic strip 30, will transmit the additional force to the diaphragm plate 70 with which it is in contact engagement. This causes downward movement of diaphragm plate 76), diaphragm 64 and valve seat 68, which is in sealing engagement with the small end of valve plug 48, whereby the valve plug 48 will be moved downward to force the lower spherical surface thereof from sealing engagement with valve seat 46, thereby admitting compressed fluid, at a higher pressure, to enter volume chamber 62 until the pressure in this chamber acting on diaphragm 64 is sufficient to overcome the additional force and return the components of the second valve means 26 to a neutral position, in which position both spherical elements of valve plug 48 are again seated in their respective valve seats 46 and 68. This increase in pressure in volume chamber 62 will be transmitted to chamber 24c in first valve means 24 through conductor tube 76. As heretofore explained, an increase in pressure in conductor tube 76 will result in a decrease in output pressure in conductor tube 108 from first valve means 24 and in conductor tube 114 from booster relay 112 and ultimately in conductor tube 118 to the fluid motor which actuates the braking mechanism. The resulting decrease in braking forces will decrease the tension in web 10 until the desired control point is reached. Conversely, should the tension in web 10 decrease below the set control point, a corresponding decrease in force acting on the tension responsive member 18 and on platform 28 will result. The force created by pressure in volume chamber 62 acting on the area of diaphragm 64 will now exceed the force acting on the diaphragm plate 70 transmitted through platform 28, and as a consequence, the diaphragm plate 70 will be moved upward to allow the valve seat 68 to disengage the upper sphere of valve plug 48. Compressed fluid in the volume chamber 62 will now escape through the bore of valve seat 68, and through the bore and passageway of diaphragm plate 70 to atmosphere, until the pressure in the volume chamber 62, acting on the diaphragm 64, is reduced to bring th force into equilibrium with the reduced tension forces. At this point, the venting of compressed fluid through valve seat 68 is stopped and the new lower pressure in volume chamber 62 is transmitted through conductor tube 76 to the first valve means 24. As heretofore explained, this reduction in pressure to the input of first valve means 24 will result in an increase in output pressure from first valve means 24 and eventually to fluid motor operated brake mechanism 14. The resulting increase in braking forces in mechanism 14 will cause tension in the web 10 to increase until the desired control point is again reached. The desired control point for tension in web 10 is obtained by varying the adjustable spring force in first valve means 24.
It should be re-emphasized that, so long as the proper pressure of compressed fluid is furnished to the input of the second valve means 26, the output pressure in conductor tube 76 from this unit will automatically and inherently vary directly in proportion to the load on platform 28, which in turn, is directly proportional to the tension in web 10.
It should also be noted that the net displacement of platform 28, due to loading and unloading forces, is zero, that any displacements are minute and momentary until the reacting forces, caused by the resultant change in pressure in volume chamber 62 can be re-established to return the diaphragm 64 and valve system to their neutral position. Since the output pressure of compressed fluid from second valve means 26 in conductor tube 76 is always directly proportional to the tension in Web 10, those skilled in the art will immediately see the advantages thereof as a means of ascertaining the amount of tension in web 10 which in turn serves as a means of operating a mechanism such as first valve means 24 to actuate a braking mechanism 14 for controlling the tension in web 10. The novel use of an elastic metal strip 30, for obtaining a 'hinging motion between platform 28 and housing 32, eliminates any friction in this motion, as would otherwise result through the use of shafts and bearings. It has been found, in practice, that it is necessary to use a dash-pot fastened to the free end of platform 28 and housing 32 in order to prevent the propagation of harmonic oscillations in volume chamber 62, which are caused by the sudden loading and unloading through the valve system.
Modified form of invention This form of the invention relates to improved control means for the operation of a pneumatic circuit to regulate the tension in a moving web of sheet material by controlling brake friction on the unwinding roll of sheet material. It relates more specifically to such control when tension variations may predominate on one side or the other of the moving web, such as might be caused by warping or uneveness in a very thick web of moving sheet material. The present form of invention provides certain 7 improvements over the above disclosed form of invention.
The invention disclosed in the other form of the invention is well suited to controlling tension in a thin, pliant film or web, where the tension of the web is evenly distributed over the length of a tension sensing roll, However, in some cases the web material may be of such thickness or stiffness that the resultant forces from tension are not evenly distributed over the length of a tension sensing roll, and in such cases the force at one end or the other will vary considerably and erratically with the movement of the web thereover. It is therefore desirable, in such cases, that the effects of the total tension in the web be sensed for control purposes.
In this form of the invention a pneumatic valve means controls fluid communication between a source of fluid under pressure and a fluid operated motor. This first pneumatic valve means is controlled by the summation of the outputs from a plurality of identical second valve means the output pressure of which is controlled by, and is proportional to, the tension of the sheet material which the fluid operated motor may control. The provision of such pneumatic means eliminates the inconvenience and undesirable features of hydraulic systems or a combination hydraulic-pneumatic system.
With more detailed reference to the modified form of the invention, the numeral 10 designates a traveling web of material, such as paper sheet, metal sheet, wire screen, or the like, which is traveling in the direction indicated by the arrow, FIG. 4, from the unwind roll 12, which roll is supported by a shaft 13 controlled by braking mechanism 14, which web is eventually delivered over the periphery of tension responsive roller member 18.
The variations of braking forces in mechanism 14 will control the amount of tension in the web 10 as it is being pulled off the unwind roll 12. Braking mechanism 14 is a commercial air brake, and is actuated by application of a varying fluid pressure in conduit 22, to change the braking forces by means of brake shoes forced against brake discs by fluid pressure confined in resilient chambers in a manner well known in the art of brakes. Variations in the fluid pressure in conduit 22 is determined by a first valve means which is indicated generally at 23, and which will be subsequently described in further detail. The first valve means 23, in turn, is controlled by a plurality of tension responsive, identical second valve means, indicated generally at 26 and 26a, as will be described in detail and shown as illustrated in FIG. 4.
Both second valve means 26 and 2611 are operated by a tension responsive member 18, which is preferably in the form of a roll, over which roll the web 10 passes in tension, thereby imparting a loading component to the roll proportional, depending upon the fleet angle of the web with respect to the roll, to the tension of the web 10. Each end of the shaft 19 of the tension responsive member 18 is mounted in respective pillow block bearings 27 and 2711 which are bolted to the respective platforms 28 and 28a of the second valve means 26 and 26a. Platforms 28 and 28a are free to make significant vertical movements by virtue of being hinged by the frictionless metal elastic strips 30 and 30a which are clamped by means of bolts 36 to bearing support platforms 28 and 28a. A T-slot is formed in each of the platforms 28 and 28a to receive the bolt heads which secure the pillow block bearings 27 and 27a carrying the shaft 19 of tension responsive member 18 to the respective platforms.
The first valve means 23 utilizes certain arrangements which are well known in the art. The first valve means 23 is described to amplify this disclosure. The first valve means 23 encloses four pressure chambers; the lower chamber 23a being formed by the valve body and a small area diaphragm 23b, the pressure in which chamber reacts on the lower side of the diaphragm 23b to modulate the output valve pressure. The two variable control signal middle chambers 23c'and 23d are formed by a ring smaller diaphragm 23 and a large diaphragm 231 and the small sealing diaphragm 23b, which chambers 23c and 23:! are in communication only with their respective conduct-or tubes 76 and 76a. The fourth and last chamber 23g is formed at the top of the first valve means by the end body closure 23h and a diaphragm, this fourth chamber 23g being in communication with conductor tube 31 and the pressure gauge 33. All of the above mentioned diaphragms are clamped on either side by a diaphragm plate and are secured together, as an assembly by a shaft 23i which extends through the center of the assembly and is secured by a terminal valve seat nut 23 The shaft 23i forms a spacer for the various diaphragms secured therearound in fluid tight relation, however the shaft 23i is drilled and cross drilled so as to vent pressure from modulating chamber 23a when the pressure in chamber 230 moves the shaft 23i upward to unseat valve 23k from the seat in valve nut 23 The forces developed on all diaphragms are co-acting on the assembly as a whole. The first valve means 23 is arranged to accommodate two variable control signals, such as the pressure signals in conductor tubes 76 and 76a, which are induced between two diaphragms of dissimilar area, the top diaphragm being of greater area and opposed over-all by an adjustable force consisting of the predetermined pressure in the upper or fourth chamber 23g. Since the variable signal pressure in the respective conductor tubes 76 and 76a is each acting independently in its own pressure chamber in the first valve means 23, each will cause a net upward force on the diaphragm assembly to result by reason of the upper diaphragms being of larger area than the lower diaphragms of the respective chambers. The net upward force on the diaphragm assembly resulting from these two pressures is the summation of forces which results from each of the pressures arriving in conductor tubes 76 and 76a. The net upward force resulting from these two pressures in conductor tubes 76 and 76a is resisted by a predetermined pressure which is introduced into the upper pressure chamber to oppose them. Therefore, at equilibrium, or control point, the pressure in the upper, fourth cham her will, for all practical purposes, be equal to the sum of the two pressures in the middle two variable control pressure chambers. The pressure gauge 33 will then read directly the sum of the two variable pressures, when the first valve means 23 is in equilibrium, or on control point. Assuming the forces in the first valve means 23 to be in equilibrium and on control point, any increase in pressure in either chamber from conductor tube 76 or 7611 will result in a net upward force which will overbalance the resisting force of the pressure in the top chamber acting on the area of its diaphragm. The diaphragm assembly will thereby be moved upward, which will cause the valving system to vent, or decrease, the output modulated pressure in conductor tube 108 until this decreasing pressure, acting on the lower small diaphragm area, restores the equilibrium of forces. Conversely, with all forces in the first valve means 23 in equilibrium, any decrease in pressure in any chamber, from conductor tube 76 or 76a, will result in a net downward force which will be overbalanced by the resisting force of the pressure in the top chamber acting on the area of its diaphragm. The diaphragm assembly will now move downward, causing the valving system to admit fluid pressure to increase the output modulated pressure in the chamber connected to conductor tube 108 until this increasing pressure, acting on the lower diaphragm of smaller area, restores equilibrium of forces. It is therefore clear that the output pressure from the first valve means 23, through conductor tube 168, is inversely proportional to the sum of the input pressures through conductor tubes 76 and 76a. The magnitude of the differences in these pressures will be dependent upon the differences in areas of the larger and smaller diaphragms in the chambers connected to input conductor tubes 76 and 76a and the area of the diaphragm in the modulating chamber connected to conductor tube 108.
It is to be noted that the area of the modulating diaphragm in the chamber which is connected to conductor tube 108 is not pneumatically balanced in the sense that any change in pressure on this diaphragm will actually shift the control point slightly. However, from a praotical standpoint, the ratio of net areas of the diaphragms in the other chambers to the area of this diaphragm is large and the resultant shift in control point is not significant. Should it be desired to prevent even this small shift in the control point, this can be accomplished through the well known practice of re-set by means of adding another small resisting diaphragm of equal area.
As an example of operation, assume the control tension in web 10 is at the desired control point, and that, at a convenient point in the process, the web 10 is passing over the periphery of tension responsive member 18. If a total tension of 100 pounds force in the web and a fleet angle of 180 degrees over the tension responsive member 18 is assumed, then the member 18 will be supporting a total load of 200 pounds on its pillow block bearings 27 and 27a which are supported by platforms 28 and 28a. If it is assumed that an effective diaphragm area of 10 square inches is in each of the identical second valve means 26 and 26a and that the load is equally distributed between them, each second valve means will have to support 100 pounds force by building up 10 pounds pressure per. square inch in the chambers 62 and 62a acting on an effective diaphragm area of 10 square inches. However, should the moving web 10 buckle, warp, or otherwise react to cause uneven distribution of the tension load on the respective ends of the tension responsive member 18, -as for instance distributing the 200-pound load by 150 pounds to pillow block bearing 27 and 50 pounds to hearing 27a, then the second valve means 26 will develop and output pressure in the chamber thereof of. 15 pounds per square inch to act upon its diaphragm area of 10 square inches, and the second valve'means 260 will vent part of its pressure to establish pounds per square inch pressure to act on the diaphragm area thereof of square inches. Thus the sum of both output pressures from the second valve means 26 and 26a in both of the above conditions will be a constant 20 pounds per square inch to resist the 200-pound loading on the tension responsive member 18, which is caused by a tension in the web 10 of 100 pounds. It is thus clear that the shifting of the load from one side to the other of the tension responsive member 18, caused by tension in the web 10 moving from one edge to the other, will not vary the sum of the output pressure in second valve means 26 and 26a so long as the total tension in moving web 19 does not change.
With the moving web 10 in tension, as above described, conductor tubes 76 and 76a will carry pressures proportional to the loading of the respective second valve means 26 and 26a and these pressures will be a sum of 20 p.s.i. Even though these pressures vary, their sum remains the same and since each pressure is coacting on an identical effective diaphragm area on the diaphragm assembly in first valve means 23, they combine to give a net upward force to the diaphragm assembly which can be resisted by a pressure of 20 p.s.i. in the upper chamber which acts downward on the diaphragm thereof on an area equivalent to one of the net diaphragm areas in either of the two middle chambers of first valve means 23. It can be seen that the pressure in the upper chamber of the first valve means 23, which is selectively predetermined by adjustment of the pressure reducing regulator 25, will determine what the sum of pressures in conductor tubes 76 and 76a must be to have the first valve means 23 in equilibrium. Also, by knowing the effective areas of the diaphragms in the second valve means 26 and 26a, and the force resultant in the angle formed by the moving web over the tension responsive member 18, it is possible to set the pressure from regulator 25 to maintain the desired tension in the web 10, by visually observing pressure gauge 33. Pressure gauge 33 can be calibrated directly in 10 terms of pounds tension in the web 10 if this convenience is desired.
Again, assuming the web 10 is moving with a tension of 100 pounds, should conditions in the process change to cause additional tension to take place in the moving web, such as a new total force of 101 pounds, then the sum of the output pressures from second valve means 26 and 260 will react to build up to 20.2 p.s.i. This increase in pressure is transmitted to the first valve means through the conductor tubes 76 and 76a to react in the middle diaphragm chambers of first valve means 23 which will cause the diaphragm assembly to move upward against the dome pressure of 20 p.s.i. in chamber 23g and will cause the lower valving mechanism 23k to vent some of the pressure in conductor tube 108. Venting of pressure from conductor tube 108 will result in decrease in pressure to braking mechanism 14 and thereby a decrease in resistance to rotation of unwind roll 12. Tension in the moving web 10 will be decreased until it returns to the desired set point at 100 pounds.
Pneumatic strain gauge The tension responsive valve means, designated generally at 26, has applications per se, other than controlling the tension on a web of sheet material. The apparatus, as best seen in FIGS. 2 and 3, is designated generally at 26, which apparatus is described in detail, for the most part, on pages 6 through 10.
It is to be pointed out that any change in force applied to the platform 28 will cause movement of diaphragm plate 70 and the unseating of inlet valve 61 or outlet valve 63, either to admit air under pressure into volume chamber 62 from a source of air pressure, or to discharge air from volume chamber 62 through diaphragm plate 70 to the atmosphere. Inlet valve 61 and outlet valve 62 are held together by a rod 48. When exact balanced pressure of both the inlet valve 61 and outlet valve 63 is had, the valve members will be seated so no air will be admitted into or no air will escape from volume chamber 62, and anything that will cause movement of the diaphragm plate 70 will cause the distance between the seats to vary until the admittance of or escape of air brings the seats back to the same spaced apart distance as the seating surfaces on inlet valve 61 and outlet valve 63, as the valves 61 and 63 are held together in fixed relation by the rod 43. Therefore, the present device can serve readily as a strain gauge for many uses, in fact to practically all uses to which the conventional electrical strain gauge is applicable and possibly to many uses to which the electrical strain gauge would not be readily applicable.
The present apparatus is so constructed as to be substantially frictionless, due to hinge strip 30 of resilient metal which is attached to the platform 28 and housing 32, which device is so designed as to give a plus or minus indication of any load placed on the platform 28. The present strain gauge may weigh accurately the change in force applied to platform 28 and will transmit an intelligible signal which is directly proportional to the load that is being opposed on the platform 28. More specifically, the present device eliminates substantially all friction and therefore gives, for the most part, a more stable pneumatic strain gauge than in use heretofore.
It is to be pointed out that the present strain gauge does not utilize frictional bushings or pin and hinge elements, but relies on the flexing of the metal elastic strip 30. within the range of the elastic limits thereof, and friction in this element is absent, from all practical standpoints. The diaphragm 64 also has a minimum of movement and has practically no friction loss, from all practical standpoints. The rapid movement of the strain gauge in either direction is stabilized by the movement of piston 88 within the body of fluid within cylinder 84, which fluid 90 is confined within the cylinder 84 by diaphragm 92. The piston 88 is in loose fitting relation with the cylinder 84 so that the fluid may flow by piston 88 when the piston is moved in either direction, however, the opening between the piston 88 and cylinder 84 will be of such closeness as to prevent rapid ingress and egress of fluid from one side of the piston 88 to the opposite side thereof. By the use of a diaphragm to confine the fluid in cylinder 84, the use of a stutfing gland is obviated and friction is minimized.
The tension responsive valve means may be used as a strain gauge for various controlling actions, such as weighing bodies of liquids in tanks, the force exerted on derricks, cranes and the like, the lifting of heavy loads, as the pressure guage 126 intermediate the tension responsive valve means 26, when used as a strain gauge and the signal amplifying and reversing pilot valve is such that the gauge 126 may be calibrated to read in the force being applied to the tension responsive valve means. If the entire load is not weighed, simple mathematical calculations may be made to determine the weight of the entire load. The gauge 126 may be so calibrated as to read in fractions of ounces, in many instances.
Web tension regulator for power driven roll The form of the invention as shown in FIG. may be used in connection with either the form of the invention as shown in FIG. 1 or that shown in FIG. 4, or it may be used independently to maintain a predetermined tension on a web to wind the Web onto a winding roll. The tension responsive member 18 is supported on the second valve assembly, designated generally at 26, which valve assembly forms a support means therefor. The web tension regulating device is designated generally at 26 and is of the same character as shown in FIG. 1, wherein the web 10 passes beneath roller 16 and over tension responsive roller 18, then beneath a roller 20 so that the tension applied by web 10 will exert a pressure on bearing 27 mounted on platform 28 in a manner set out above for the forms of the invention as shown in FIGS. 1 and 4. However, the winding roll 201 is journaled on supports 202, and has a fluid actuated clutch 204 intermediate the roll 201 and a drive pully 206. The drive pulley 206 is driven by an endless transmission member, such as a belt 208 which passes over a drive pulley 210 on drive shaft to the motor gear reduction drive unit 212.
The fluid actuated clutch 204 has a rotary fluid seal 214 I connected thereto and to a'oonduit 216 which leads into controller casing designated generally at C, which casing houses the various regulators, gauges, and valves, as shown within the dashed outline in FIG. 1. A fluid supply pipe 120 passes into controller casing C and conductor tubes 60 and 76 lead therefrom to the second valve means, which forms a regulating device or strain gauge 26 so as to control the tension on web 10 in the manner set out for the device is desclosed in FIG. 1.
A volume bottle or capacity chamber 75 is provided within casing C which is in fluid communication with conduit 76 which conduit leads from the first valve means 24 to a second valve means 26 so as to eliminate surges and eliminate vibration. The valve 77 is also provided in the conduit 76 so as to regulate the opening or orifice within conduit 76, thereby minimizing sudden changes of pressure in conduit 76.
By having the tension roll 201 maintained with a given pull thereon, the slack may be taken out of web 10 and the web wound onto the roll 201 under the desired tension. Furthermore, the regulator 26 prevents the web breaking because of excessive tension being exerted thereon.
As mentioned above, the tension on web 10 may be regulated both by the tension regulating arrangement shown in FIG. 1, by applying brake pressure to retard the unwinding of roll 12 and by applying the necessary torque on roll 201 to Wind the web 10 tightly on the roll without undue tension being applied thereto. However, a constant drag or retarding of roll 12 may be had without the use of the regulating system as shown in FIG. 1, and
12 the entire regulation of the tension may be carried out by the tension regulating arrangement as shown in FIG. 5 so as to cause fluid actuated clutch 204 to slip when a pull beyond a predetermined amount is exerted on web 10.
It is to be understood that the invention, while being shown as applied to several different modes of practice, may be changed in minor details of construction and adaptations made to different installations without departing from the spirit of the invention or the scope of the appended claims.
Having thus clearly shown and described the invention, what is claimed as new and desired to be secured by Letters Patent is:
1. A tension control means for a traveling web of sheet material comprising:
(a) a rotating roll from which the sheet material is being unwound,
(b) a fluid pressure responsive brake for said roll,
(c) a source of fluid under pressure,
((1) a first valve means having a movable valve member opposed by an adjustable force and connected between said fluid pressure source and said brake for controlling the operation of the brake,
(e) a tension responsive member in engagement with the web of sheet material to be movable in response to change in tension of the sheet material and connected to be completely supported by a plurality of identical second movable valve means which together send a cumulative pressure signal proportional to the total tension in the web of sheet material regardless of the variations in the tension in the web material from one side to the other,
(1) which said cumulative pressure signals control the first valve means solely as a fuction of the tension force of the sheet material,
(2) each said second movable valve means comprising a diaphragm having an opening formed therethrough, with a valve seat formed thereon and surrounding each said opening,
(3) a pair of valve assemblies, each comprising a top valve member and a lower valve member rigidly connected together, with each said top valve member being associated with the valve seat on each said diaphragm in operative relation,
(4) a lower stationary valve seat associated with each said second movable valve means and being a spaced distance below the valve seat of each said diaphragm,
(i) the lower valve member of each valve assembly being operatively associated with each said stationary valve seat to admit fluid under pressure into pressure relation with each diaphragm,
(5) each said top valve seat on the respective diaphragms being movable in response to the variation in the tension on the web and adapted to control the pressure under the diaphragm, which pressure becomes the modulated output signal which is accumulative in the first valve means to become proportional to the total tension of the web,
(i) each said top valve member adapted to bleed fluid from below the respective diaphragms upon upward movement of the respective diaphragms when the respective lower valve members are seated, and
(f) the first and second valve means co-acting to vary the pressure to the fluid pressure responsive brake to obtain the desired tension in the sheet material as predetermined by the force adjustment of the first valve means.
2. In an apparatus for controlling the tension on a traveling web of sheet material comprising:
(a) a roll supported in journaled relation,
.(l) a. further outlet within said support member connected to the fluid outlet means on said support member, p
(m) a unitary valve within said inlet conduit and valving said last mentioned outlet,
(n) unitary valve seating in the same direction to close said inlet of said conduit and said outlet of saidlast mentioned outlet,
() said outlet conduit connected with a first fluid responsive valve means,
(p) a second source of fluid supply connected to said first fluid responsive valve means,
(q) a unitary valve means in said first fluid valve responsive valve means, (r) a further unitary valve member within said first valve means having two valve members thereon, (s) a further fluid inlet and a fluid outlet Within said first valve means,
(t) a valve seat within said fluid inlet and a valve seat in said fluid outlet,
(u) a diaphragm responsive member mounting the seat of said fluid outlet,
(v) a member forming a seat for said fluid inlet,
(w) a further outlet to bleed air pressure from said fluid outlet line,
(x) a booster relay connected in fluid responsive relation to said air outlet line, and
(y) a further air supply line connected to said booster line to boost the pressure a predetermined amount to control the discharge of said air supply pressure into a conduit leading to said fluid actuated means to control the rotation of said roll in response to the load applied to said load support member by said tension responsive member.
3. In an appartus for controlling the tension on a traveling web of sheet material comprising:
(a) a roll containing sheet material supported in journaled relation,
(b) fluid actuated means adapted to control the rotation of said roll,
(c) a tension responsive member operatively engaging said sheet material so as to sense the tension thereof and to move in response to changes of the tension in said sheet material,
(.d) a support means mounting said tension responsive member and including a chamber defined by a diaphragm and said support means,
(e) fluid outlet means connected to said chamber and associated with said support means,
(f) an inlet conduit connected to said chamber,
(g) a conductor tube leadingfrom said chamber,
(h) a unitary valve means located within said inlet conduit and valving said fluid outlet means,
(i) said unitary valve means seating in the same direction so as to close said inlet conduit and said fluid outlet means in response to the instantaneous tension on said tension responsive member,
(j) a fluid responsive first valve means having upper and lower diaphragms defining a first chamber therebetween,
(1) said first valve means having a body portion with a pressure inlet valve seat therein a spaced distance below said lower diaphragm and defining a modulating pressure chamber between said lower diaphragm and the body portion, 1
(2) said upper and lower diaphragms having a longitudinally apertured spacer, including a valve seat within said longitudinal aperture, interconnecting said diaphragms, which longitudinal aperture in said spacer forms an eX- haust passageway which is connected in fluid communication with said modulating chamber,
(k) a pressure supply conduit connected to said modulating chamber, with said pressure inlet valve seat located within said pressure supply conduit,
(1) a unitary valve within said pressure modulating chamber having two valve members thereon,
(m) one said valve member of said unitary valve coopearting with said pressure inlet'valve seat and the other valve member of said unitary valve cooperating with said seat in said exhaust passageway so that movement of said diaphragms controls the flow of fluid across said valve members,
(n) said conductor tube being connected to said first chamber of said fluid responsive means,
(0) a source of fluid pressure connected to said inlet conduit,
(p) an outlet conductor tube leading from said modulating chamber of said fluid pressure responsive valve and connected to said fluid actuated means for controlling the rotation of said roll in response to the tension of said web of sheet material.
4. In an apparatus for controlling the tension of a traveling web of sheet material comprising:
(a) a roll of sheet material supported in journaled relation,
(b) fluid actuated, means adapted to control the totation of said roll,
(c) a tension responsive member operatively engaging the traveling web of sheet material,
(d) a support member mounting said tension responsive member,
(e) a base,
(f) a hinge means hingeably connecting at least a portion of said support member with said said base,
(g) fluid outlet means associated with said support member,
(h) diaphragm means mounted on said base,
(i) said base having means forming a fluid chamber therein,
(j) an inlet conduit connected wth said chamber for supplying a source of fluid under pressure,
(k) an outlet conduit leading from said chamber,
(1) a further outlet within said support member and including said fluid outlet means,
(m) a unitary valve within said inlet conduit and valving said last mentioned outlet,
(n) said unitary valve seating in the same direction to close said inlet of said conduit and said outlet of said last mentioned outlet,
(0) said outlet conduit leading from said chamber connected with a first fluid responsive valve means,
(p) a unitary valve means in said first fluid responsive valve means and including a further unitary valve member having two valve members thereon,
(q) a further fluid inlet adapted to be connected to a pressure source and a fluid outlet within said first fluid responsive valve means,
(r) a valve seat within said further fluid inlet and a valve seat in said last mentioned fluid, outlet,
(s) a diaphragm responsive member mounting the seat of said last mentioned fluid outlet,
(t) a further outlet adapted to bleed air pressure from the upstream side of said fluid outlet and the downstream side of said further fluid inlet,
(u) the last mentioned fluid outlet having conduit means connected in fluid pressure responsive relation to said fluid actuated means that is connected 1 5 1 I5 downstream of said further outlet so as to control said piston to the opposite side thereof to pass fluid the rotation of said roll in response to the load apfrom one side of said, piston to the other side thereof plied to said load support member by said tension upon movement of the piston within said cylinder, responsive member. and v 5. An apparatus for controlling the tension of a travel- 5 (h) said cylinder being at least partially filled with a ing Web of sheet material as defined in claim 4; wherein fluid.
(a) a cylinder is mounted on said base,
(b) a connecting rod References Cited by the Examiner (c) a piston mounted on and secured to said connect- UNITED STATES PATENTS 7 ing rod and being fitted within said cylinder, 10 2,462,558 2/1949 Scheuermann 242 7 5 43 (d) an apertured diaphragm surrounding said con- 2,501,957 3/1950 M0ore 7 5 necting rod and being fitted in fluid tight relation 2,601,367 7/1952 Alyea 7 -g5 transversely Ofsaid cylinder, 2,974,894 3/1961 Aaron 242 75;43 (e) said. connecting rod being in sealed relation with 3,101,915 8/1963 Aaron et a1. 5
saiddiaphragm, 15 1 (f) said conecting rod connected to a portion of said FRANK I. COHEN, Primary Examiner.
support member to move said piston upon move- MERVIN STEIN Examiner ment of the portion of said support member, (g) said piston having a fluid passage from one side of N. L. MINTZ; Assistant Examiner.