CA1209418A - Servo valve - Google Patents
Servo valveInfo
- Publication number
- CA1209418A CA1209418A CA000436518A CA436518A CA1209418A CA 1209418 A CA1209418 A CA 1209418A CA 000436518 A CA000436518 A CA 000436518A CA 436518 A CA436518 A CA 436518A CA 1209418 A CA1209418 A CA 1209418A
- Authority
- CA
- Canada
- Prior art keywords
- inlet
- control member
- outlet ports
- recesses
- housing
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
- B65H23/00—Registering, tensioning, smoothing or guiding webs
- B65H23/02—Registering, tensioning, smoothing or guiding webs transversely
- B65H23/0204—Sensing transverse register of web
- B65H23/0212—Sensing transverse register of web with an element utilising fluid flow
Landscapes
- Physics & Mathematics (AREA)
- Fluid Mechanics (AREA)
- Multiple-Way Valves (AREA)
- Servomotors (AREA)
- Fluid-Pressure Circuits (AREA)
- Fluid-Driven Valves (AREA)
Abstract
Abstract of the Disclosure The housing has an inner area defined by end walls, side walls, a top wall, and a bottom wall having a flat inner surface. Inlet and outlet ports open through the flat inner surface. The inlet port is arranged to be connec-ted to a supply source of pneumatic pressure and the outlet ports are arranged to be connected to an actuator. A control member in the housing has a pair of recesses facing the inner surface in association with the inlet and outlet ports. The control member is suspended by a pair of leaf springs. A
diaphragm is controlled by a pneumatic correction signal force from a low pressure sensor circuit and is arranged under the influence of such signal force to selectively position the control member relative to the inlet and outlet ports for controlling power to the actuator.
diaphragm is controlled by a pneumatic correction signal force from a low pressure sensor circuit and is arranged under the influence of such signal force to selectively position the control member relative to the inlet and outlet ports for controlling power to the actuator.
Description
~2~ 8 SERVo VALVE
Background of the Invention This invention relates to new and useful improve-ments in pneumatic servo valves used with automatic web guiding systems.
Automatic web guiding systems are used to control the lateral position of moving webs of material, such as paper, plastics, textiles and other flexible materials being processed in continuous or roll form. A signal is generated by the position of the web edge relative to a sensor, and the signal output either directly con-trols an actuator connected to positioning means or in-directly controls an actuator through a servo valve which is connected to a web positioner.
Various types of servo valves have been incorporated into automatic web guiding systems to control the opera-tion of actuator means, such as a spool type servo valve.
The primary problem of the spool type pneumatic valve is the sticking due to friction and contamination from the air. In comparison to hydraulic valves, the pneumatic valve lacks the flushing and lubrication provided by the hydraulic fluid of a hydraulic valve.
~50st all-pneumatic automatic web guiding systems have not used servo valves, but have operated their actuators directly with "feeler" type sensors that ride i"'~"~ ' ~2~
on the web edge, or an open vacuum type sensor which has one or more "intake" orifices supporting the web edge. Both systems are used in conjunction with spring-opposed single acting actua-tors.
A low pressure, non-contact pneumatic web sensor is highly desirable for sensing thin, delicate webs~
Such a sensor requires a servo valve to provide the air pressure and flow necessary to operate an actuator for web controlling means.
The idea of a suspension valve is not new or unique.
For example, FLUID POWER CONTROL, (Blackburn, Reethof, and Shearer, ~I.I.T. Press, 1960, p. 241.) describes a small suspension valve in which the flexure hinges, the stationary support block, and the moving block are all machined from a single block. Due to its flexure limi-tations and portage configuration, this valve would be limited and essentially unsuited as an automatic guiding system servo valve. Furthermore~ the single block con-stxuction and portage configuration make this valve costly to manufacture and assemble.
Summary of the ~nvention According to the invention and forming a primary objective thereof, a friction free servo valve is provided with increased flexure and improved flow. Such increased flexure and improved flow makes a low-pressure air system applicable.
'~q~4'~8 Another object of the invention is to provide a valve o~ the type described that is capable of precise and accurate manufacture and is easily assembled and disassembled.
Another object of the invention is to provide a valve of t~e type described that is not affected in its operation ~y the usual type contaminants that may be present in air systems such as dust.
In carrying out the objectives of the invention, a housing has inlet and outlet ports opening into an inner surface thereof, and a control member is enclosed in the housing and has a pair of recesses facing such inner surface in association with inlet and outlet ports. Resilient suspension means suspend the control member from the top wall of the housing and hold it operatively in close spaced relation to the inner surface. The housing includes movable pressure responsive means controlled by pneumatic correction signals from a sensor. The pressure responsive means operatively engages the control member laterally relative to the resilient suspension means and is arranged under the influence of the pneumatic correction signal force from the sensor to selectively position the control member relative to the inlet and outlet ports for controlling power to actuator means. A preferred form of suspension comprises a pair of leaf springs. The control member and the inner surface of the housing have a novel cooperating reIationship which provides an efficient operation of the --4~
actuator means in response to a sensor signal as well as an efficient and accurate construction and assembly.
The invention will be better understood and addi-tional objects and advantages will become apparent from the following description taken in connection with the accompany-ing drawings.
Brief Description of the Drawings Figure 1 is a perspective view of a servo valve incorporating features of the present invention;
Figure 2 is a longitudinal vertical sectional view of the valve taken on the line 2-2 of Figure l; and Figures 3, 4 and 5 are sectional views taken on the lines 3-3, 4-4, and 5-5 of Figure 2, respectively.
' De*a'i'led De's'crip'tion of' a' Preferred Embodiment The valve of the invention comprises an assembly of a subbase 10 having a base 12 secured thereto~ as by screws 14, Figure 5, in turn supporting front and rear walls 16 and 18, respectively, fastened thereto by screws 20.
Walls 16 and 18 ha~e inturned top portions 22 which clamp a top wall 24 therebetween by means of elongated screws 26. Side walls 28 are secured to the front and rear walls by screws 30. The top surface 12a of base 12 comprises a machined surface.
A first rear upright plate 36 is secured to the exterior of rear wall 18, by screws 38! and a second up-right plate 40 is secured to the rear of plate 36, as by screws 42. These plates seat on a notched portion 44 of --s--the base 10 and have cooperating recesses to form a diaphragm chamber 46 enclosing a thin, flexible diaphragm 48,securely clamped between the upright plates 36 and 40.
Diaphragm 48 has a reinforcing body portion 50 integral therewith.
A control member or block 54 is suspended from the top of the housing by a pair of leaf springs 56 and has clearances at its ends for control movement in the housing.
These leaf springs are clamped between the inturned portions 10 22 of the walls 16 and 18 and the top wall 24. The bottom portions of the leaf springs are clamped between end plates 58 of the control member secured, as by screws 60, to such'control member. The end plates 58 have an upright extension 62, and one of these end extensions is secured 15 to the body portion 50 of the diaphragm by a horizontal rod 64 passing freely through a bore 66 in wall 18 and plate 36. The upright extension 62 at the other end of the housing is engaged by a biasing spring 70 made variable in its force by an adjusting screw 72 in the front wall.
The bottom surface 54a of con-trol member 54 comprises a machined surfac~ and has a pair of enlarged inverted cup-shaped circular recesses 76 and 78 spaced a short distance apart and also spaced inwardly from the respective ends of the control member 54. These recesses are associated 25 with inserts 80 and 82, respectively, fitted in bores 84 in the base 12. Insert 80 has an upriyht bore or passage-way 86 associated with recess 76 and insert 82 has an up-11~
right bore or passageway 88 associated with recess 78.
Cutting of the recesses 76 and 78 comprises an extension of the cutting step of bores 84 for the plugs, as will be more apparent hereinafter.
With particular reference to Figures 2 and 4, inserts 80 and 82 project inwardly into a recess 92 cut in the top surface 12a of base 12. This recess has a central portion 92a between the inserts 80 and 82 and extends beyond the ends of the inserts 80 and 82 to form end portions 92b. Recess 92 has a contoured fitted association with the sides of the inserts.
The present valve is arranged to be associated with an air pressure system 100, Figure 5, for adjusting a piston operated actuator means 102 by suitable connecting air lines conduits 104 and 106 under the control of a sensor 108 associated with a traveling web 110. Sensor 108 has an air input line 112 and a pressure signal line 114 the pressure in which is altered by the lateral position of the web 110 whereby response of the actuator means 102 through the valve under the influence of the sensor 108 will adjust a mechanism according to lateral movement of the web as is well known in the art.
Porting of the valve to accomplish operation of the actuator means 102 in response to the sensor 108 comprises a pressure inlet passageway 120 which leads from a suitable connection, not shown, with the air pressure system 100 through the subbase 10 and base 12 to the recess area 92a between the inserts 80 and 82. Recess areas 92b at the ends of the recess 92 are in communication with exhaust passageways 122 for the respective inserts which ~c~
. -7-lead from these respective recess portions through the base 12 and subbase 10 to atmosphere. Lines 104 and i06 from the actuator means 102 are connected, by suitable fittings, not shown, to passageways 124 and 126, respectively, leading inwardly through the subbase 10 into the lower end of re-spective bores 86 and 88~ Pressure existing in the passageway 120 is stopped at the control member 54 when it is centered over the inserts 80 and 82 but upon lateral movement of the control member, it will allow pressure therefrom to flow through one or the other of the bores 86 and 88 for adjusting the actuator means 102, the exhaust from the actuator means flowing through the other bore 86 or 88 into its exhaust passageway 122.
.Pressure inlet passageway 120 also-communicates with a passageway 130 having a flow restricting valve 132 project-ing into it for reducing the flow in the passageway 130.
Passageway 130 has two branch passageways 134 and 136. Passage-way 134 is connected to one side of the sensor 10~ by the line 112 and passa~eway 136 is connected to the other.side of the sensor by the line 114. A flow restricting valve 138 is mounted~in the branch passageway 136 and provides a low flow to prevent the entry of cont~m;n~nts from the air surrounding sensor 108 from entering line 114. A branch passageway 140 in the subbase 10 has an upward extension 142 in the rear wall portion 36, 40 in communication with the diaphragm cham~ber 46.
The restricting valve 132 provides a low pressure system for the sensor 108 and the restricting orifice 138 in turn provides ~small purge flow in the low pressure sensor circuit as will now be more fully described.
Suspension of the valve member 54 in the initial setting of the valve is made so that the recesses 76 and 78 precisely are in alignment over the inserts 80 and 82, respectively.
~uch precision suspension is accomplished by adjustment of the adjustment screw 72 to position the member 54 in lateral balanced relation with the pressure in the diaphragm chamber 46. In such balanced position of the valve member 54, no air flows between inlet passageway 120 and either of the bores 80 or 82. However, as the web 110 shits laterally, the influence of the line 114 in the sensor will change and the diaphragm will shift the member 54 one way or the other for producing a following movement of the actuator means 102. For example, an inward movement of the web 110 into the sensor will decrease the influence of the high pressure side 112 on the lower pressure side 114 whereby the diaphragm will be moved to the right under the action of the biasing spring 70 so as *o shift the member 54 to the right. This will put pressure from passageway 120 through recess 76, bore 80 and-passageway 124 to the one side of the actuator means 102. In such movement, the actuator exhausts through line 106, passageway 126, bore 82, and its passage-way 122. If the web should shi~t in a direction away from the sensor, the recess 78 and associated structure comes into play for opposite movement.
The present valve is considered to have several important features. One such feature comprises the leaf spring suspension of the valve member 54. The member 54 is suspended a minute clearance above the surface 12a so that while providing a fairly good seal for air flow at the same time provides free movement of the block from ~Z~ 3 g the diaphragm. Since the member 54 does not bear against the surface 12a, there is no wear and also small dust particles will not affect efficient operation of the valve.
Another feature of the valve is that the cup-shaped recesses 76 and 78 as well as the inserts 80 and 82 are enlarged and provide a maximum flow of driving power to the actuator means 102 with a minimum movement of the valve block 54. That is, as seen in Fiyure 4 and designated by the numerals 76a and 78a which designate an ad~usted position of the recesses 76 and 78, respectively, a substantially large segment of recess is opened up for power flow ana exhaust. The valve is thus highly responsive in its function by minimum movement of member 54. ~lso, the valve is highly responsive to the low pressure signal of the sensor, such low pressure allowing use of the valve with thin or fragile webs 110.
Still another feature of the valve is the relationship that the hbllow inserts 80 and 82 have with the recesses 76 and 78, respectively. By such arrangement, the valve can be precisely constructed during manufacture in that with suitable anchoring of the block 54 within the valve, the bores for insertion of the inserts and for cutting of the recesses can be accomplished in one step. Thus, misalignment of the valve parts in manufacture is remote. However, the bores 84 for the plugs 80 and 82 can be reamed larger than the recesses 76 and 78 after the control block assembly 54 ha`s been removed. In such case, the plugs will be slightly larger than their respective recesses which will tend to re-duce leakage.
The valve can be disassembled and reasse~bled without having to use a fragile shim in the final assembly, as required in previous designs. In the subject valve, the shim for determining the clearance between the moving and stationary parts is used to space the parts while the ports are being drilled and reamed, with the parts firmly clamped together. The suspension springs are permanently clamped to their supports and their fasteners are sealed.
The shims are then discarded after the ports are machined.
Another feature of the invention is that all the portage is enclosed within the housing and therefore is not sub]ect to external damage.
It is to be understood that the form of my invention herein shown and described is to be taken as a preferred example cf the same and that various changes in the shape, size and arrangement of parts ma~ be resorted to without departing from the spirit of my invention, or the scope of the subjoined claims. For example, the above description associates the valve with a double acting actuator 102 whereas the valve can as well be associated with a single ` 20 acting actuator. Such is illustrated in phantom lines in Figure`5 wherein one of the lines, such as line 106, can lead to one side of a single acting piston type actuator 102' having spriny return.
Having thus described my invention, I claim:
Background of the Invention This invention relates to new and useful improve-ments in pneumatic servo valves used with automatic web guiding systems.
Automatic web guiding systems are used to control the lateral position of moving webs of material, such as paper, plastics, textiles and other flexible materials being processed in continuous or roll form. A signal is generated by the position of the web edge relative to a sensor, and the signal output either directly con-trols an actuator connected to positioning means or in-directly controls an actuator through a servo valve which is connected to a web positioner.
Various types of servo valves have been incorporated into automatic web guiding systems to control the opera-tion of actuator means, such as a spool type servo valve.
The primary problem of the spool type pneumatic valve is the sticking due to friction and contamination from the air. In comparison to hydraulic valves, the pneumatic valve lacks the flushing and lubrication provided by the hydraulic fluid of a hydraulic valve.
~50st all-pneumatic automatic web guiding systems have not used servo valves, but have operated their actuators directly with "feeler" type sensors that ride i"'~"~ ' ~2~
on the web edge, or an open vacuum type sensor which has one or more "intake" orifices supporting the web edge. Both systems are used in conjunction with spring-opposed single acting actua-tors.
A low pressure, non-contact pneumatic web sensor is highly desirable for sensing thin, delicate webs~
Such a sensor requires a servo valve to provide the air pressure and flow necessary to operate an actuator for web controlling means.
The idea of a suspension valve is not new or unique.
For example, FLUID POWER CONTROL, (Blackburn, Reethof, and Shearer, ~I.I.T. Press, 1960, p. 241.) describes a small suspension valve in which the flexure hinges, the stationary support block, and the moving block are all machined from a single block. Due to its flexure limi-tations and portage configuration, this valve would be limited and essentially unsuited as an automatic guiding system servo valve. Furthermore~ the single block con-stxuction and portage configuration make this valve costly to manufacture and assemble.
Summary of the ~nvention According to the invention and forming a primary objective thereof, a friction free servo valve is provided with increased flexure and improved flow. Such increased flexure and improved flow makes a low-pressure air system applicable.
'~q~4'~8 Another object of the invention is to provide a valve o~ the type described that is capable of precise and accurate manufacture and is easily assembled and disassembled.
Another object of the invention is to provide a valve of t~e type described that is not affected in its operation ~y the usual type contaminants that may be present in air systems such as dust.
In carrying out the objectives of the invention, a housing has inlet and outlet ports opening into an inner surface thereof, and a control member is enclosed in the housing and has a pair of recesses facing such inner surface in association with inlet and outlet ports. Resilient suspension means suspend the control member from the top wall of the housing and hold it operatively in close spaced relation to the inner surface. The housing includes movable pressure responsive means controlled by pneumatic correction signals from a sensor. The pressure responsive means operatively engages the control member laterally relative to the resilient suspension means and is arranged under the influence of the pneumatic correction signal force from the sensor to selectively position the control member relative to the inlet and outlet ports for controlling power to actuator means. A preferred form of suspension comprises a pair of leaf springs. The control member and the inner surface of the housing have a novel cooperating reIationship which provides an efficient operation of the --4~
actuator means in response to a sensor signal as well as an efficient and accurate construction and assembly.
The invention will be better understood and addi-tional objects and advantages will become apparent from the following description taken in connection with the accompany-ing drawings.
Brief Description of the Drawings Figure 1 is a perspective view of a servo valve incorporating features of the present invention;
Figure 2 is a longitudinal vertical sectional view of the valve taken on the line 2-2 of Figure l; and Figures 3, 4 and 5 are sectional views taken on the lines 3-3, 4-4, and 5-5 of Figure 2, respectively.
' De*a'i'led De's'crip'tion of' a' Preferred Embodiment The valve of the invention comprises an assembly of a subbase 10 having a base 12 secured thereto~ as by screws 14, Figure 5, in turn supporting front and rear walls 16 and 18, respectively, fastened thereto by screws 20.
Walls 16 and 18 ha~e inturned top portions 22 which clamp a top wall 24 therebetween by means of elongated screws 26. Side walls 28 are secured to the front and rear walls by screws 30. The top surface 12a of base 12 comprises a machined surface.
A first rear upright plate 36 is secured to the exterior of rear wall 18, by screws 38! and a second up-right plate 40 is secured to the rear of plate 36, as by screws 42. These plates seat on a notched portion 44 of --s--the base 10 and have cooperating recesses to form a diaphragm chamber 46 enclosing a thin, flexible diaphragm 48,securely clamped between the upright plates 36 and 40.
Diaphragm 48 has a reinforcing body portion 50 integral therewith.
A control member or block 54 is suspended from the top of the housing by a pair of leaf springs 56 and has clearances at its ends for control movement in the housing.
These leaf springs are clamped between the inturned portions 10 22 of the walls 16 and 18 and the top wall 24. The bottom portions of the leaf springs are clamped between end plates 58 of the control member secured, as by screws 60, to such'control member. The end plates 58 have an upright extension 62, and one of these end extensions is secured 15 to the body portion 50 of the diaphragm by a horizontal rod 64 passing freely through a bore 66 in wall 18 and plate 36. The upright extension 62 at the other end of the housing is engaged by a biasing spring 70 made variable in its force by an adjusting screw 72 in the front wall.
The bottom surface 54a of con-trol member 54 comprises a machined surfac~ and has a pair of enlarged inverted cup-shaped circular recesses 76 and 78 spaced a short distance apart and also spaced inwardly from the respective ends of the control member 54. These recesses are associated 25 with inserts 80 and 82, respectively, fitted in bores 84 in the base 12. Insert 80 has an upriyht bore or passage-way 86 associated with recess 76 and insert 82 has an up-11~
right bore or passageway 88 associated with recess 78.
Cutting of the recesses 76 and 78 comprises an extension of the cutting step of bores 84 for the plugs, as will be more apparent hereinafter.
With particular reference to Figures 2 and 4, inserts 80 and 82 project inwardly into a recess 92 cut in the top surface 12a of base 12. This recess has a central portion 92a between the inserts 80 and 82 and extends beyond the ends of the inserts 80 and 82 to form end portions 92b. Recess 92 has a contoured fitted association with the sides of the inserts.
The present valve is arranged to be associated with an air pressure system 100, Figure 5, for adjusting a piston operated actuator means 102 by suitable connecting air lines conduits 104 and 106 under the control of a sensor 108 associated with a traveling web 110. Sensor 108 has an air input line 112 and a pressure signal line 114 the pressure in which is altered by the lateral position of the web 110 whereby response of the actuator means 102 through the valve under the influence of the sensor 108 will adjust a mechanism according to lateral movement of the web as is well known in the art.
Porting of the valve to accomplish operation of the actuator means 102 in response to the sensor 108 comprises a pressure inlet passageway 120 which leads from a suitable connection, not shown, with the air pressure system 100 through the subbase 10 and base 12 to the recess area 92a between the inserts 80 and 82. Recess areas 92b at the ends of the recess 92 are in communication with exhaust passageways 122 for the respective inserts which ~c~
. -7-lead from these respective recess portions through the base 12 and subbase 10 to atmosphere. Lines 104 and i06 from the actuator means 102 are connected, by suitable fittings, not shown, to passageways 124 and 126, respectively, leading inwardly through the subbase 10 into the lower end of re-spective bores 86 and 88~ Pressure existing in the passageway 120 is stopped at the control member 54 when it is centered over the inserts 80 and 82 but upon lateral movement of the control member, it will allow pressure therefrom to flow through one or the other of the bores 86 and 88 for adjusting the actuator means 102, the exhaust from the actuator means flowing through the other bore 86 or 88 into its exhaust passageway 122.
.Pressure inlet passageway 120 also-communicates with a passageway 130 having a flow restricting valve 132 project-ing into it for reducing the flow in the passageway 130.
Passageway 130 has two branch passageways 134 and 136. Passage-way 134 is connected to one side of the sensor 10~ by the line 112 and passa~eway 136 is connected to the other.side of the sensor by the line 114. A flow restricting valve 138 is mounted~in the branch passageway 136 and provides a low flow to prevent the entry of cont~m;n~nts from the air surrounding sensor 108 from entering line 114. A branch passageway 140 in the subbase 10 has an upward extension 142 in the rear wall portion 36, 40 in communication with the diaphragm cham~ber 46.
The restricting valve 132 provides a low pressure system for the sensor 108 and the restricting orifice 138 in turn provides ~small purge flow in the low pressure sensor circuit as will now be more fully described.
Suspension of the valve member 54 in the initial setting of the valve is made so that the recesses 76 and 78 precisely are in alignment over the inserts 80 and 82, respectively.
~uch precision suspension is accomplished by adjustment of the adjustment screw 72 to position the member 54 in lateral balanced relation with the pressure in the diaphragm chamber 46. In such balanced position of the valve member 54, no air flows between inlet passageway 120 and either of the bores 80 or 82. However, as the web 110 shits laterally, the influence of the line 114 in the sensor will change and the diaphragm will shift the member 54 one way or the other for producing a following movement of the actuator means 102. For example, an inward movement of the web 110 into the sensor will decrease the influence of the high pressure side 112 on the lower pressure side 114 whereby the diaphragm will be moved to the right under the action of the biasing spring 70 so as *o shift the member 54 to the right. This will put pressure from passageway 120 through recess 76, bore 80 and-passageway 124 to the one side of the actuator means 102. In such movement, the actuator exhausts through line 106, passageway 126, bore 82, and its passage-way 122. If the web should shi~t in a direction away from the sensor, the recess 78 and associated structure comes into play for opposite movement.
The present valve is considered to have several important features. One such feature comprises the leaf spring suspension of the valve member 54. The member 54 is suspended a minute clearance above the surface 12a so that while providing a fairly good seal for air flow at the same time provides free movement of the block from ~Z~ 3 g the diaphragm. Since the member 54 does not bear against the surface 12a, there is no wear and also small dust particles will not affect efficient operation of the valve.
Another feature of the valve is that the cup-shaped recesses 76 and 78 as well as the inserts 80 and 82 are enlarged and provide a maximum flow of driving power to the actuator means 102 with a minimum movement of the valve block 54. That is, as seen in Fiyure 4 and designated by the numerals 76a and 78a which designate an ad~usted position of the recesses 76 and 78, respectively, a substantially large segment of recess is opened up for power flow ana exhaust. The valve is thus highly responsive in its function by minimum movement of member 54. ~lso, the valve is highly responsive to the low pressure signal of the sensor, such low pressure allowing use of the valve with thin or fragile webs 110.
Still another feature of the valve is the relationship that the hbllow inserts 80 and 82 have with the recesses 76 and 78, respectively. By such arrangement, the valve can be precisely constructed during manufacture in that with suitable anchoring of the block 54 within the valve, the bores for insertion of the inserts and for cutting of the recesses can be accomplished in one step. Thus, misalignment of the valve parts in manufacture is remote. However, the bores 84 for the plugs 80 and 82 can be reamed larger than the recesses 76 and 78 after the control block assembly 54 ha`s been removed. In such case, the plugs will be slightly larger than their respective recesses which will tend to re-duce leakage.
The valve can be disassembled and reasse~bled without having to use a fragile shim in the final assembly, as required in previous designs. In the subject valve, the shim for determining the clearance between the moving and stationary parts is used to space the parts while the ports are being drilled and reamed, with the parts firmly clamped together. The suspension springs are permanently clamped to their supports and their fasteners are sealed.
The shims are then discarded after the ports are machined.
Another feature of the invention is that all the portage is enclosed within the housing and therefore is not sub]ect to external damage.
It is to be understood that the form of my invention herein shown and described is to be taken as a preferred example cf the same and that various changes in the shape, size and arrangement of parts ma~ be resorted to without departing from the spirit of my invention, or the scope of the subjoined claims. For example, the above description associates the valve with a double acting actuator 102 whereas the valve can as well be associated with a single ` 20 acting actuator. Such is illustrated in phantom lines in Figure`5 wherein one of the lines, such as line 106, can lead to one side of a single acting piston type actuator 102' having spriny return.
Having thus described my invention, I claim:
Claims
1.
A servo valve for controlling output pneumatic power to actuator means, said valve comprising (a) a housing having an inner area defined by end walls, side walls, a top wall, and a bottom wall having a flat inner surface, (b) an inlet port opening through said flat inner surface, (c) outlet ports also opening through said surface, (d) pressure inlet means leading to said inlet port, said outlet ports being arranged to be connected to actuator means, (e) a control member in said housing having a pair of recesses facing said inner surface in association with said inlet and outlet ports, (f) resilient suspension means secured between said control member and the top wall of said housing suspending said control member adjacent said surface, (g) and movable pressure responsive drive means in said housing arranged to be controlled in its movement by a pneumatic correction signal force from a sensor, (h) said drive means operatively engaging said control member laterally relative to said resilient suspension means and arranged under the influence of pneumatic correction signal force from a sensor to selectively position said control member relative to said inlet and outlet ports for controlling power to actuator means.
2.
The servo valve of claim 1 wherein said resilient suspension means comprises leaf springs.
3.
The servo valve of claim 1 wherein said resilient suspension means comprises a pair of leaf springs secured to said top wall of said housing and suspending said con-trol member in close but freely movable spaced relation from said flat inner surface.
4.
The servo valve of claim 1 wherein said housing has a body portion including said inner area with said end walls fastened thereto, said control member also having end walls fastened thereto, said resilient suspension means comprising a pair of leaf springs having one end clamped to said top wall in a position opposite from said flat inner surface and their other end clamped between the control member and its end walls.
5.
The servo valve of claim 1 wherein said movable pressure responsive means comprises a diaphragm mounted in one of said end walls.
6.
The servo valve of claim 1 wherein said housing has a body portion including said inner area with said end walls hastened thereto, said control member also having end walls fastened thereto, said resilient suspension means comprises a pair of leaf springs having one end clamped to said top wall in a position opposite from said flat inner surface and their other end clamped between the control member and its end walls.
7.
The servo valve of claim 1 wherein said movable pressure responsive means comprises a diaphragm mounted in one of said end walls, and adjustable biasing means in said other end wall engageable laterally with said control member for providing a balanced position of said control member relative to said inlet and outlet ports.
8.
The servo valve of claim 1 wherein said control member comprises a block and said resilient suspension means comprises leaf springs, said block having a flat surface on the side opposite the suspended spring cooperating in close relation with said flat inner surface of said housing and having said pair of recesses therein for association with said inlet and outlet ports.
9.
The servo valve of claim 8 wherein said housing includes a bottom wall fastened thereto and provided with said flat inner surface and said inlet and outlet ports, said recesses being substantially larger in cross section than said ports and said ports comprising bores in a plug which is fitted in openings through said bottom wall and which forms a seal between said inlet and outlet ports, the openings in said bottom wall for said plugs being of the same size and shape in cross section as said recesses so that in the formation of said valve, said recesses can be formed as a continuation of the openings through said bottom wall.
10.
The servo valve of claim 8 wherein said housing includes a bottom wall fastened thereto and provided with said flat inner surface and said inlet and outlet ports, said recesses being substantially larger in cross section than said ports and said ports comprising bores in a plug which is fitted in openings through said bottom wall and which forms a seal between said inlet and outlet ports, the diameter of the openings in said bottom wall and the diameter of said plugs being larger than the diameter of their respective recesses.
11.
The servo valve of claim 8 wherein said housing includes a bottom wall fastened thereto and provided with said flat inner surface and said inlet and outlet ports, said recesses being substantially larger in cross section than said ports and said ports comprising bores in a plug which is fitted in openings through said bottom wall and which forms a seal-between said inlet and outlet ports, the openings in said bottom wall for said plugs being of the same size and shape in cross section as said recesses so that in the formation of said valve, said recesses can be formed as a continuation of the openings through said bottom wall, said flat inner surface on said bottom wall having a recessed area at said inlet port extending substantially the width of said plug whereby a small movement of said control member opens a widened communicating area between said inlet port and one of said outlet ports.
12.
A servo valve for controlling output pneumatic power to actuator means, said valve comprising (a) a housing having an inner area defined by end walls, side walls, a top wall, and a bottom wall having a flat inner surface, (b) an inlet port opening through said flat inner surface, (c) outlet ports also opening through said surface, (d) pressure inlet means leading to said inlet port, said outlet ports being arranged to be connected to actuator means, (e) a control member in said housing having a pair of recesses facing said inner surface in association with said inlet and outlet ports, (f) means supporting said control member for lateral shifting movement, (g) movable pressure responsive drive means in said housing, (h) a pneumatic correction sensor and circuit also arranged to be connected to said pressure inlet means and operatively connected to said drive means, (i) pressure reducing means in said sensor circuit, (j) said drive means operatively engaging said control member laterally and arranged under the influence of the reduced pressure of the pneumatic correction sensor to selectively position said control member relative to said inlet and outlet ports for controlling power to actuator means.
13.
A servo valve for controlling output pneumatic power to actuator means, said valve comprising (a) a housing having an inner area defined by end walls, side walls, a top wall, and a bottom wall having a flat inner surface, (b) an inlet port opening through said flat inner surface, (c) outlet ports also opening through said surface, (d) pressure inlet means leading to said inlet port, said outlet ports being arranged to be connected to actuator means, (e) a control member in said housing having a pair of recesses facing said inner surface in association with said inlet and outlet ports, (f) means supporting said control member for lateral shifting movement, (g) said control member having a flat surface cooperating in close relation with said flat inner surface and having said pair of recesses in association with said inlet and outlet ports, (h) said recesses being substantially larger in cross section than said ports and said ports comprising bores in a plug which is fitted in openings through said bottom wall and which forms a seal between said inlet and outlet ports, the openings in said bottom wall for said plugs being of the same size and shape in cross section as said recesses so that in the formation of said valve, said recesses can be formed as a continuation of the openings through said bottom wall, (i) and movable pressure responsive drive means in said housing arranged to be controlled in its movement by a pneumatic correction signal force from a sensor, (j) said drive means operatively engaging said control member laterally and arranged under the influence of the pneumatic correction sensor to selectively position said control member relative to said inlet and outlet ports for controlling power to actuator means through said recesses.
A servo valve for controlling output pneumatic power to actuator means, said valve comprising (a) a housing having an inner area defined by end walls, side walls, a top wall, and a bottom wall having a flat inner surface, (b) an inlet port opening through said flat inner surface, (c) outlet ports also opening through said surface, (d) pressure inlet means leading to said inlet port, said outlet ports being arranged to be connected to actuator means, (e) a control member in said housing having a pair of recesses facing said inner surface in association with said inlet and outlet ports, (f) resilient suspension means secured between said control member and the top wall of said housing suspending said control member adjacent said surface, (g) and movable pressure responsive drive means in said housing arranged to be controlled in its movement by a pneumatic correction signal force from a sensor, (h) said drive means operatively engaging said control member laterally relative to said resilient suspension means and arranged under the influence of pneumatic correction signal force from a sensor to selectively position said control member relative to said inlet and outlet ports for controlling power to actuator means.
2.
The servo valve of claim 1 wherein said resilient suspension means comprises leaf springs.
3.
The servo valve of claim 1 wherein said resilient suspension means comprises a pair of leaf springs secured to said top wall of said housing and suspending said con-trol member in close but freely movable spaced relation from said flat inner surface.
4.
The servo valve of claim 1 wherein said housing has a body portion including said inner area with said end walls fastened thereto, said control member also having end walls fastened thereto, said resilient suspension means comprising a pair of leaf springs having one end clamped to said top wall in a position opposite from said flat inner surface and their other end clamped between the control member and its end walls.
5.
The servo valve of claim 1 wherein said movable pressure responsive means comprises a diaphragm mounted in one of said end walls.
6.
The servo valve of claim 1 wherein said housing has a body portion including said inner area with said end walls hastened thereto, said control member also having end walls fastened thereto, said resilient suspension means comprises a pair of leaf springs having one end clamped to said top wall in a position opposite from said flat inner surface and their other end clamped between the control member and its end walls.
7.
The servo valve of claim 1 wherein said movable pressure responsive means comprises a diaphragm mounted in one of said end walls, and adjustable biasing means in said other end wall engageable laterally with said control member for providing a balanced position of said control member relative to said inlet and outlet ports.
8.
The servo valve of claim 1 wherein said control member comprises a block and said resilient suspension means comprises leaf springs, said block having a flat surface on the side opposite the suspended spring cooperating in close relation with said flat inner surface of said housing and having said pair of recesses therein for association with said inlet and outlet ports.
9.
The servo valve of claim 8 wherein said housing includes a bottom wall fastened thereto and provided with said flat inner surface and said inlet and outlet ports, said recesses being substantially larger in cross section than said ports and said ports comprising bores in a plug which is fitted in openings through said bottom wall and which forms a seal between said inlet and outlet ports, the openings in said bottom wall for said plugs being of the same size and shape in cross section as said recesses so that in the formation of said valve, said recesses can be formed as a continuation of the openings through said bottom wall.
10.
The servo valve of claim 8 wherein said housing includes a bottom wall fastened thereto and provided with said flat inner surface and said inlet and outlet ports, said recesses being substantially larger in cross section than said ports and said ports comprising bores in a plug which is fitted in openings through said bottom wall and which forms a seal between said inlet and outlet ports, the diameter of the openings in said bottom wall and the diameter of said plugs being larger than the diameter of their respective recesses.
11.
The servo valve of claim 8 wherein said housing includes a bottom wall fastened thereto and provided with said flat inner surface and said inlet and outlet ports, said recesses being substantially larger in cross section than said ports and said ports comprising bores in a plug which is fitted in openings through said bottom wall and which forms a seal-between said inlet and outlet ports, the openings in said bottom wall for said plugs being of the same size and shape in cross section as said recesses so that in the formation of said valve, said recesses can be formed as a continuation of the openings through said bottom wall, said flat inner surface on said bottom wall having a recessed area at said inlet port extending substantially the width of said plug whereby a small movement of said control member opens a widened communicating area between said inlet port and one of said outlet ports.
12.
A servo valve for controlling output pneumatic power to actuator means, said valve comprising (a) a housing having an inner area defined by end walls, side walls, a top wall, and a bottom wall having a flat inner surface, (b) an inlet port opening through said flat inner surface, (c) outlet ports also opening through said surface, (d) pressure inlet means leading to said inlet port, said outlet ports being arranged to be connected to actuator means, (e) a control member in said housing having a pair of recesses facing said inner surface in association with said inlet and outlet ports, (f) means supporting said control member for lateral shifting movement, (g) movable pressure responsive drive means in said housing, (h) a pneumatic correction sensor and circuit also arranged to be connected to said pressure inlet means and operatively connected to said drive means, (i) pressure reducing means in said sensor circuit, (j) said drive means operatively engaging said control member laterally and arranged under the influence of the reduced pressure of the pneumatic correction sensor to selectively position said control member relative to said inlet and outlet ports for controlling power to actuator means.
13.
A servo valve for controlling output pneumatic power to actuator means, said valve comprising (a) a housing having an inner area defined by end walls, side walls, a top wall, and a bottom wall having a flat inner surface, (b) an inlet port opening through said flat inner surface, (c) outlet ports also opening through said surface, (d) pressure inlet means leading to said inlet port, said outlet ports being arranged to be connected to actuator means, (e) a control member in said housing having a pair of recesses facing said inner surface in association with said inlet and outlet ports, (f) means supporting said control member for lateral shifting movement, (g) said control member having a flat surface cooperating in close relation with said flat inner surface and having said pair of recesses in association with said inlet and outlet ports, (h) said recesses being substantially larger in cross section than said ports and said ports comprising bores in a plug which is fitted in openings through said bottom wall and which forms a seal between said inlet and outlet ports, the openings in said bottom wall for said plugs being of the same size and shape in cross section as said recesses so that in the formation of said valve, said recesses can be formed as a continuation of the openings through said bottom wall, (i) and movable pressure responsive drive means in said housing arranged to be controlled in its movement by a pneumatic correction signal force from a sensor, (j) said drive means operatively engaging said control member laterally and arranged under the influence of the pneumatic correction sensor to selectively position said control member relative to said inlet and outlet ports for controlling power to actuator means through said recesses.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US42866882A | 1982-09-30 | 1982-09-30 | |
| US428,668 | 1982-09-30 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1209418A true CA1209418A (en) | 1986-08-12 |
Family
ID=23699872
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000436518A Expired CA1209418A (en) | 1982-09-30 | 1983-09-12 | Servo valve |
Country Status (4)
| Country | Link |
|---|---|
| JP (1) | JPH0249409B2 (en) |
| CA (1) | CA1209418A (en) |
| DE (1) | DE3335124A1 (en) |
| GB (1) | GB2128373B (en) |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE1163103B (en) * | 1957-05-17 | 1964-02-13 | Oilgear Co | Servo-controlled flat valve with one control element |
| GB881655A (en) * | 1957-05-17 | 1961-11-08 | Oilgear Co | Improvements in or relating to fluid flow control valves |
| DE1119073B (en) * | 1958-05-03 | 1961-12-07 | Christian Buerkert | Valve with pneumatic or hydraulic drive |
| FR2031798A5 (en) * | 1969-02-07 | 1970-11-20 | Rhone Poulenc Sa | |
| CA970247A (en) * | 1972-08-31 | 1975-07-01 | Gerald W. Bernhoft | Air-oil amplifier |
| GB1406635A (en) * | 1972-10-30 | 1975-09-17 | Abdo J T | Control valve |
| DE2553250C3 (en) * | 1975-11-27 | 1981-10-29 | Festo-Maschinenfabrik Gottlieb Stoll, 7300 Esslingen | Diaphragm-operated 5/2 multi-way valve |
-
1983
- 1983-09-12 CA CA000436518A patent/CA1209418A/en not_active Expired
- 1983-09-22 JP JP17687983A patent/JPH0249409B2/en not_active Expired - Lifetime
- 1983-09-28 DE DE19833335124 patent/DE3335124A1/en active Granted
- 1983-09-29 GB GB08326038A patent/GB2128373B/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| DE3335124C2 (en) | 1990-08-09 |
| JPH0249409B2 (en) | 1990-10-30 |
| GB2128373B (en) | 1986-02-05 |
| DE3335124A1 (en) | 1984-04-05 |
| GB2128373A (en) | 1984-04-26 |
| JPS5977104A (en) | 1984-05-02 |
| GB8326038D0 (en) | 1983-11-02 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |