US 3310942 A
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Description (OCR text may contain errors)
March 28, i9? w. 'a'. STANFORD AIR PUMP DEVICE 3 Sheets-Sheet l Filed July 26, 1965 MalCh 28, 1967 w. T. sTANFoRD 3,310,942
AIR PUMP DEVICE Filed July 26, 1965 3 Sheets-Sheet 2 /75- f3.9 4:76 4Q [Qa wrap/ve ys,
Mwch 28, E967 w. T. STANFORD AIR PUMP DEVI CE 3 Sheets-Sheet 5 Filed July 26, 1965 FVGA `Fuss United States Patent Q 3,310,942 Am PUMP DEVICE William T. Stanford, Salem, lll., assigner to Wood Newspaper Machinery Corporation, Plainfield, NJ., a corporation of Virginia Filed July 26, 1965, Ser. No. 474,707 6 Claims. (Cl. 60-52) T his invention relates to an improved air pump device, and more particularly, to an air pump web guide for controlling the winding of paper on a roll. The device may also be used for positioning, holding, lifting, or otherwise moving objects in the web guide, machine tool, and other fields.
This invention was made initially for use in the web guide field, although it has numerous other applications. Therefore, 4the following description will be for its use in the web gui-de field, it being understood that it has application in other iields.
In the past, web guides for guiding a web of material have used a hydraulic system having a sensing device for sensing the edge position of a web, a valve for translating the signal from the sensing device into direction and magnitude of any lateral deviation of the web, a hydraulic cylinder connected to the valve for receiving oil to cause the cylinder to move, and a hydraulic power source including pump, motor and reservoir. This prior system had disadvantages in that there was a constant circulation of oil that had to be pumped under high pressure. This moving or recirculating of oil required work output from an electric motor. The oil needed a large reservoir with suitable cooling means, such as fins, since the oil would get hot in the system. The heat was detrimental and created sealing problems. Further, this prior system required an electrical source for the motor, starters, and/ or main disconnects, and these had to be explosion proof since the atmosphere in which the web guide is used frequently contains volatile fumes. The explosion proof apparatus was costly.
One of the principal objects of the present invention is to provide a web guide system having a hydraulic circuit in which t-he oil moves only when a correction of the workpiece is needed. Another object is to provide an air pump on a web guide, thereby eliminating the electrical motor and the constant recirculation of oil with the resulting disadvantages. Another object is to provide a system in which the user needs only a source of compressed air to operate the unit, there being no requirement for any .electrical connections. Another object is to provide a versatile system which can supply a wide range of operating forces on the roll or workpiece to be moved by simply varying the air pressure from the air sources.
Still another object is to provide a system of sensing which gives immediate response because of a by-pass located as close to the pilot valve as possible. Another object is to provide a simple and inexpensive device and system which are actuated solely by air pressure and which can be use-d to position, hold, lift, or otherwise move another member.
These and other objects and `advantages will become apparent hereinafter.
T-he present invention comprises a system having an air power unit for pumping oil in a hydraulic system, a pilot valve, which receives signals from a sensing device-and transmits `them into direction and magnitude to a hydraulic cylinder which is connected to a member to be moved. rl`he invention is also embodied in the pilot valve itself, and in the assembly of said units in a casing, and in the air pressure system whereby a by-pass is located close to the pilot Valve.
The invention also consists in `the parts and in the arrangements and combinations of parts hereinafter de- ICC scribed and claimed. In the accompanying drawings which form part of this specification and wherein like numerals and symbols refer to like parts wherever they occur:
FIG. 1 is a diagrammatic view or flow diagram of a system embodying the present invention, said system shown guiding a web,
FIG. 2 is a vertical cross-sectional View of an air pump embodying the present invention, parts being shown diagrammatically,
FIG. 3 is a fragmentary side elevational view of said air pump showing the surge tank,
FIG. 4 is a fragmentary side elevational View of said air pump showing the air connections,
FIG. 5 is a view showing the sensing device or pressure head assembly, and
FIG. 6 is a top plan View of the lower head of said sensing device.
Referring now to the drawings in detail, it will be seen that the particular embodiment of the invention which has been illustrated is shown in a web guide system. This system comprises a power unit 1, a pilot valve 2, a hydraulic cylinder 3, and a sensing device 4. The purpose of this system is to use the edge 5 of a web 6 coming from a roll and moving toward a rewind roll 7 to transmit a signal to the pilot valve 2 which directs oil received from the power unit 1 to one side or the other side of a piston 8 in the hydraulic cylinder 3 for moving the rewind roll 7 so that -the web material 6 rolls up with its edge 5 aligned. The system includes a pneumatic circuit P and `a hydraulic circuit H.
A diagrammatic view of the system embodying this invention is shown in FIG. l. For its operation, the system needs only a source of compressed air at 10 to 70 p.s.i. capable of supplying about 1.5 cubic feet per minute. Of course, this will vary within limits in some exceptional situations.
The factory air supply 9 is regulated by a regulator 10 and is directed into a tube .11 and a conduit 12 having a needle valve 13 therein to throttle the pressure down. The tube 11 leads to the power unit 1 having an air switch 14 and air piston 15 therein for placing oil in the hydraulic system H under pressure and pumping it at predetermined times upon signal. The air piston 15 is connected to a single piston pump 16 in the power unit 1, said pump 16 having an oil line 17 leading into it and an oil line 18 leaving it. The out oil line 18 has a surge tank 19 and a lter 20 connected thereto and leads to the inlet 2,1 of a pilot valve 2 for supplying oil at about 150 p.s.i. thereto. Oil is exhausted from -the exhaust port 22 of the pilot valve 2 through the oil line 17 having a filter 70 and a regulator 24 therein and leading back to the power unit 1. Two tubes 25 and 26 with filters 27 and 28 therein lead from the' pilot valve 2 to opposite ends 29 and 30 of a hydraulic cylinder 3 having the piston 8 with a rod 31 thereon which leads to the mandrel holding a roll of' material or workpiece 7, either directly as shown or through a linkage.
The pneumatic system P contains the conduit 12 which leads to a sensing device 4 having a lower head 32 positioned below the web 6 at the edge 5 thereof. An upper head 33 is positioned above the web 6, there being a gap 34 between the lower head 32 and the upper head 33. Each head 32 and 33 has an opening or slot 35 therein, and is mounted on a support 36. The upper head 33 is connected to a line 37 extending to the pilot valve 2. Within or in close proximity to the pilot valve 2 is a by-pass 38 connecting the conduit 12 and the line 37 at a point remote from the sensing device 4. The pilot valve 2 has a diaphragm or air piston 39 thereon which receives signals from the sensing device 4 for moving a 3 four way valve 40 ytherein in the proper direction and amount for directing the proper amount of oil from the hydraulic system H to one side of the piston 8 in the hydraulic cylinder 3.
The sensing device 4, best shown in FIGS. and 6, comprising the registering sensing heads 32 and 33, each having a slot 3S or holes therein, adjustably secured to the support 36. The sensing device 4 may be one of several different types, but as shown herein, the lower sensing head 32 receives air from the conduit 12, which has a source of regulated air pressure therein, and blows it up through the gap 34 to the spaced upper sensing head 33. The edge 5 of the web 6 passes through the gap 34. The upper sensing head 33 is connected to the line 37 extending Ito the pilot valve 2. The by-pass 38 connecting the conduit 12 and the line 37 is positioned as close as possible to the pilot valve 2. Its purpose will be explained later. The conduit 12 and line 37 may be of any suitable length. In practice, each is frequently to 20 feet long. As the web 6 moves laterally between the upper and lower heads 32 and 33 it changes the air pressure in the line 37. Because of the by-pass 38 located in or adjacent to the pilot valve 2, this change is sensed immediately at the pilot valve 2 and eliminates the time that would otherwise be required for the pressure differential to move through the long length of the line 37 from the upper head 33 to the pilot valve 2.
The by-pass 38 blows a slight pressure through the line 37 to the upper head 33 purging it of foreign material and creating an air column in line 37 so that when the web edge 5 moves over the slot 35 in the sensing device 4, the difference in air pressure is instantly transmitted to the by-pass 38 which is located in or near the pilot valve 2. Thus, the length of the line 37 becomes immaterial when the by-pass 38 is provided. The by-pass 38 also gives increased sensitivity. The pressure in the conduit 12 is preferably about 4 p.s.i. in a typical installation, with about .25 p.s.i. through the by pass 38. The purpose of this is to obtain an instantaneous reaction at the p-ilot valve 2, instead of waiting for the pressure to move through the long line 37 to the pilot valve 2. When the web edge S moves laterally, thepressure in the line 37 is increased or decreased.
The pilot valve 2 comprises a cylindrical casing 41 having a large diametered portion 42 with movable means 39, such as a diaphragm or piston, movably mounted therein and sealed at the edge by sealing means. The casing 41 has an inlet 43 for receiving air in the main pressure chamber 44 above the diaphragm 39, there being a bleeder port 45 on the exhaust side 46 of said diaphragm 39. A four way valve or spool 40 is secured to the diaphragm 39 and 'contains lands 47 and grooves 48 which cooperate with the oil inlet 21 and exhaust 22 to form the four Way valve, which has a port 49 connected to the tube 25 extending to one end 29 of the hydraulic cylinder 3 and another port 50 connected to the tube 26 extending to the opposite end 30 of said hydraulic cylinder 3. A spring 51 is mounted within a housing 52 on said pilot valve 2 for normally biasing the spool 40 and diaphragm 39 toward the main pressure chamber 44. Actu- Vation of the spool 40 can connect the oil inlet 21 with one side of the hydraulic cylinder 3 While exhausting from the other of said tubes, or the spool 40 can disconnect the inlet 21 and exhaust 22 from the tubes 25 and 26.
The power unit 1 comprises a cylindrical casing 53 having an inlet 54 for receiving compressed air. The power unit 1 is mounted on a pedestal and has an air switch 14 therein connected by a shaft 55 to movable means 15, such as a diaphragm or air piston, whose outer edge is sealed by suitable means, such as the O ring 56. The piston is of relatively large diameter and is provided with a hydraulic piston 16 of much smaller diameter, which is free to slide within the hydraulic bore 57 forming an oil pressure chamber 58. Suitable seals, such as O rings 59, are provided in the power unit 1. A passage 6i) connects the chamber 61 on the hydraulic piston side of the piston 15 With the air switch 14, there being a chamber 62 on the -air switch side of the piston 15. The air switch 14 is operated when the pressure within the chamber 61 of the air piston 15 reaches a predetermined low. The pressure chamber 58 has an oil inlet port 63 and an oil outlet port 64, each port having a check valve 65 so that oil can ow in only one direction. A tube 18 connects the outlet port 64 with the inlet port 21 oi the pilot valve 2. An oil reservoir 67 is provided within the shell or casing 68 above the power unit 1 and below the pilot valve 2 to make certain that a suicient supply of oil is available at all times. A pipe 69 connected to the tube 66 leads to a surge tank 19. The compressed air which is directed into the power unit 1 exerts a pressure on the air piston 15, which forces the hydraulic piston 16 against the oil with much greater pressure, thereby exerting a high pressure on the oil in the system at all times. Suitable in-line oil lters 70 are provided at various places within the system to lter out any impurities in the oil.
The hydraulic cylinder 3 comprises a casing 71, having a hydraulic piston 8 therein with a rod 31 thereon. The rod 31 is connected to the shaft of a roll 7 for receiv-4 ing the web of material 6. Hydraulic chambers 72 and 73 are provided on opposite sides of the piston 8 in the hydraulic cylinder 3. The chambers 72 and 73 are cou-j nected to the oil lines 25 and 26, respectively, so that oil under pressure from the power unit 1pis directed through the pilot valve 2 into one of the chambers 72 or 73 thereby moving the piston 8 and exhausting the other of said chambers'. This causes the rod 31 to move the roll of web material 6 a predetermined amount ir one direction or another.
As best shown in FIG. 2, the entire air pump device A may be included in a single cylindrical casing 74 so that the by-pass 38, the pilot valve 2, and the power unit 1 are all assembled into one unit, which also forms an oil reservoir 67 therein. As shown, the pilot valve 2 forms the top 75 of the device, and the by-pass 38 is adjacent to and connects the two ports which receive line 37 and Iconduit 12 leading to the sensing device 4. The power unit 1 is positioned in and forms the lower portion of said casing 74, its air switch 14 being in a lower position. The lair piston 15 is mounted thereabove and moves the smaller hydraulic piston 16 thereabove which is within a smaller diametered portion 57 having an oil inlet 63 and an oil outlet 64 therein, each with a check valve 65 connected ,thereto. The annular space 76 around the upstanding portion 77 and the space thereabove within the casing 68 form the oil reservoir 67. The tube 66 extends through this oil reservoir 67 from the oil outlet 64 to the oil inlet 21 of the pilot valve 2. The tube 66 has an loil filter 70 therein and is connected to the pipe 69 leading into the surge tank 19, which is positioned outside of said casing 74.
The operation of this invention is believed to be apparent from the foregoing description, but a further explanation follows. The power unit 1 provides a constant head of oil at the pilot valve 2 which, upon any movement of the pilot valve spool 40, causes a flow of oil to one end of the hydraulic cylinder 3 which is connected to the mechanism for shifting the roll 7 of the web of material. The pilot valve 2 receives its signal from the sensing device 4.
In a system where a roll of material needs to be accurately re-wound to square up the edges, it is obvious that the system is in equilibrium and the oil is at rest but under pressure in the entire system so long as the web edge 5 does not deviate laterally from its proper position over the opening 35 in the sensing head 4. If the web edge 5 does not deviate, no oil is being pumped within the power unit 1 or in the pilot valve 2. When the web edge moves, the pressure in the line 37 exerted by the air pressure in the conduit 12 changes thereby instantly moving the diaphragm 39 in the pilot valve 2 and causing the spool 4t) to change its position to allow oil to flow under pressure from one of the oil lines 25 or 26 into the proper side of the hydraulic cylinder 3 to move the roll 7 laterally to cause the Web edge 5 to move to its proper position over the holes 35 in the sensing head 4.
The present system eliminates the necessity of a rotary pump which must be large enough to give a maximum rate of correction when called upon even though the normal flow of oil is very slight. This means that the excess oil in the prior system had to be discharged through a by-pass relief valve at the pump resulting in the generation of heat, which is highly undesirable, and resulting in a very ineicient system. Further, the electric motor and other parts of the prior system had to be explosion proof in design because of the volatility of inks, compounds and thinners used in the vicinity of the web guiding operation. The present system eliminates the need of an electric motor, the constant flow of oil, the explosion-proof construction, and the electrical systern. The present pump 16 is of the single piston type which is actuated by a reversing air piston operated from an air source and requiring no electrical connections. The balanced system causes the air piston 1S to pump oil only when required to do so and maintains 150 pounds of pressure at the pilot valve 2 at all times, but pumps oil only when needed. Thus, all of the heat of a by-pass system has been eliminated. Further, since oil is pumped only when needed, no large reservoir of oil is needed to dissipate the heat generated by constant circulation. The present system requires about one quart of oil as against two or three gallons of oil in the prior System.
As best shown in FIG. 2, because of the small reservoir 67 and small size of the power unit 1 and pilot valve 2, the units may be assembled within a single casing 74 which forms a compact unit which can be mounted to the frame of the process equipment and which requires for operation only a low pressure air line that makes available 1.5 cubic feet of air per minute. This air line 9 may have a regulator 1Q in it to change the effective pressure being supplied, so that the present equipment can be used with heavier work loads by simply increasing the incoming pressure. v
This invention can be used not only in the web guiding held, as illustrated, but also in machine tool positioning systems and may also be used on small portable powered lifting devices, such as for lifting large rolls of paper and holding them in an elevated position. All that is required is a source of compressed air to the power unit 1 and this is effectively transmitted into much higher oil pressures due to the novel arrangements shown herein. In normal practice, the piston 15 in the power unit 1 is about 35 times as big as the hydraulic piston 16 so that the pressure is magnified 35 times. Thus, a relatively low air pressure is transformed into a high oil pressure.
This invention is intended to cover all changes and modifications of the example of the invention herein chosen for purposes of the disclosure, which do not constitute departures from the spirit and scope of the invention.
What I claim is:
1. A system for moving a workpiece comprising a source of air, a conduit connecting said source of air to a sensing device for sensing the proper position of said workpiece, a pilot valve and operating means there-for, a line from said sensing device to said operating means of said pilot valve, a by-pass between said conduit and said line, said pilot valve and its operating means translating the signal from said sensing device into direction and magnitude of the movement of said workpiece, a hydraulic cylinder connected to said pilot valve for receiving oil to cause said workpiece to move, and a hydraulic power source for supplying oil under pressure to said pilot valve, the oil in said system being non-circulating and 6 being pumped only when said workpiece is required to lbe moved by said hydraulic cylinder, said oil being pumped by pneumatic means.
2. A system for moving a workpiece comprising a source of compressed air, a conduit connecting said source of compressed air to a sensing device for sensing the proper position of said workpiece, a pilot valve and operating means therefor, a line from said sensing device to said operating means of said pilot valve, a by-pass between said conduit and said line for creating a limited How of compressed air in said line from said by-pass to said sensing device to effect instantaneous transmission of signals from said sensing device to said pilot valve and its operating means, said pilot valve translating the signal lfrom said sensing device into direction and magnitude of the movement of said workpiece, said by-pass positioned adjacent to said pilot valve, a hydraulic cylinder connected to said pilot valve for receiving oil to cause said workpiece to move, and a hydraulic power source for supplying oil under pressure to said pilot valve, the oil in said system being pumped only to maintain pressure and when said workpiece is required to be moved by said hydraulic cylinder, said oil being pumped by pneumatic means in said power unit. i
3. A system for moving a workpiece in a predetermined direction and proper magnitude, said system having a pneumatic circuit and a hydraulic circuit, said system requiring solely a source of compressed air for its operation, a conduit connecting `said source of compressed air to a sensing device which responds to the position of an edge of a web of material going to said workpiece, a pilot valve and operating means therefor, a line from said sensing device to said operating means of said pilot valve, a by-pass between said conduit and said line adjacent to said pilot valve, said pilot valve and its operating means translating the signal from said sensing device into direction and magnitude of said web of material, a power unit for maintaining said hydraulic circuit under pressure, said power unit connected to said source of compressed air, said compressed air adapted to pump oil under pressure upon actuation of an air switch therein, a hydraulic cylinder connected to said pilot valve, said hydraulic cylinder having a piston therein adapted to move said workpiece, said hydraulic cylinder having means for receiving oil on opposite sides of said piston in a direction and amount determined by said pilot valve, said hydraulic system having non-circulating oil therein which is pumped only when the workpiece is required to be moved.
4. A system for moving a workpiece in a predetermined direction and proper magnitude, said system having a pneumatic circuit and a hydraulic circuit, said system adapted to be connected to a source of compressed air, a conduit connecting said source of compressed air to a sensing device which responds to the position of an edge of a web of material going to said workpiece, a pilot valve and operating means therefor, a line from said sensing device to said operating means of said pilot valve, a by-pass between said conduit and said line adjacent to said pilot valve for conducting a limited amount of air through said line from said by-pass to said sensing device, said pilot valve and its operating means translating the signal from said sensing device instantaneously into direction and magnitude of said web of material, a power unit for maintaining said hydraulic circuit under pressure, said power unit connected to said source of compressed air, said compressed air adapted to pump oil under pressure upon actuation of an air switch therein, a hydraulic cylinder connected to said pilot valve, said hydraulic cylinder having a piston therein adapted to move said workpiece, said hydraulic cylinder having means fo-r receiving oil on opposite sides of said piston in a direction and amount determined by said pilot valve, said hydraulic system hav- Iing non-circulating oil therein which is pumped only when the workpiece is required to be moved.
5. An air pump device for 4causing a workpiece to be moved in a predetermined direction and proper magnitude, said device having a cylindrical casing with portions of a pneumatic circuit and a hydraulic circuit therein, said device having an inlet for receiving a source of compressed air, said device having ports therein receiving a line and a conduit vconnected to a sensing device, a bypass in said device connecting said ports, a pilot valve in said device forming the top portion thereof, said pilot valve having a diaphragm therein movable upon a signal from said line connected to said sensing device, said diaphragm connected to move a four way valve in said hydraulic circuit for directing oil to yone of two outlets,
' a power unit in said device for maintaining said hydraulic circuit under pressure, said power unit connected to said inlet and actuated by compressed air, said power unit having an air switch and a pist-on therein which pumps oil under pressure upon actuation of said air switch, a tube connecting said power unit to said pilot valve, an oil reservoir formed in said casing between said pilot valve and said power unit, and a surge tank connected to said tube.
6. A unitary air pump device having an upstanding cylindrical casing, said casing having a pedestal portion adapted to rest on a supporting surface, a power unit supported by said pedestal portion and having an outer periphery forming a portion of said cylindrical casing, said power unit having an air switch in the lower portion thereof and a hydraulic piston in the upper portion thereof for pumping oil, a shell supported by the outer upper portion of said power unit, said shell forming a portion of said cylindrical casing and a reservoir therein above said power unit, a pilot valve supported by said shell and forming a portion of said cylindrical casing and the top thereof, said pilot valve having a diaphragm in the upper portion thereof connected to hydraulic valve means in the lower portion thereof, said hydraulic valve means connected to said power unit, said power unit having an inlet in said reservoir for receiving oil, and an inlet in the upper portion of said device for receiving air from a sensing device, an air inlet in said device for said power unit, and two hydraulic outlets adapted to be connected to a hydraulic cylinder.
References Cited by the Examiner UNITED STATES PATENTS 2,365,536 12/1944 Fischer et al 60-52 X 2,938,347 5/ 1960 Sturgis 60--52 3,159,170 12/1964 Callan' 242-57.1 X
EDGAR W. GEOGHEGAN, Primary Examiner.