Electric to fluid signal valve unit

A low-powered electric to fluid valve unit includes a housing having a supply port connected to a pneumatic source and an output port connected to a pneumatic operator. A disc spring is clamped about the periphery within the housing. The peripheral portion is connected by a plurality of spring arms to a sealing disc located between the inner end of the supply port and an exhaust port. The disc spring is formed of a suitable spring material which may be of a magnetic or non-magnetic material. The disc is coated with a silicone rubber sealant. The housing is closed by an electromagnetic assembly threaded into the housing and having an E-shaped iron core having a coil wound about the central leg and connected to a signal source. The central core leg is formed with an exhaust opening and aligned with the spring disc. An iron pad is provided on the backside of the spring disc and is spaced slightly from the E-shaped iron core to define a working air gap. The pad provides a relatively large cross-sectional flux path for the magnetic field. The housing is formed of plastic components for ease of production. When the magnetic field starts movement of the spring, the air gap shortens and the spring snaps to close the exhaust port and open the supply port. When the magnetic field and holding force drops, the spring initiates return movement. The gap lengthens and creates a reverse snap action closing of the valve.

BACKGROUND OF THE INVENTION 
This invention relates to an electric to fluid signal valve unit for 
generating of a fluid signal related to an electrical signal and 
particularly to such a unit for forming a digital fluid signal. 
In many control systems, various conditions are conveniently sensed with 
electrical sensing devices. Control operators may advantageously, in many 
cases, be hydraulic and/or pneumatic devices, with suitable transducers 
employed to interface the electrical sensors to the control operators. 
Such operator devices may include a mechanical valve coupled to an 
operating solenoid. They are, generally, relatively large and require 
significant power for operation and there is a significant demands for 
miniaturization in valve structures in which a small electrical signal may 
control signal flow. 
For example, with the development of fluidic systems, low level, digital 
fluid signals may be employed. In such systems, a low level on-off fluidic 
signal may signal and control a relatively large flow control device. 
Thus, the fluidic system replaces the usual power consuming electrical 
amplifying systems. 
Generally, in a fluid system, in addition to being rapid acting, the signal 
transducer should produce a very positive on-off characteristic with 
essentially no leakage. A substantial number of interfacing devices may 
also be required in any one system and the unit should have a minimum 
cost, operate at relatively low pressures and flow rates and with 
reliable, accurate outputs. The electrical operating system should also be 
designed for low power consumption and a minimum size in order to minimize 
the size of the overall structure. 
SUMMARY OF THE PRESENT INVENTION 
The present invention is particularly directed to a small, low-powered, 
electric to fluid signal valve means particularly adapted for 
incorporation into a fluid control system. Generally, in the present 
invention, a flat spring means having a minimal spring rate is secured in 
overlying relation to a port means. An electromagnetic means is secured to 
the backside of the spring means and is operable to attract the spring 
means and rapidly open the port means to produce a binary or on-off type 
signal. The spring means preferably is a flat, disc-like element such as 
disclosed in U.S. Pat. No. 3,662,779 to U. Weber et al. Such a flat spring 
includes a plurality of spring arms joining an outer mounting portion with 
a central sealing portion, formed with a sealing means and biased by the 
spring arms to a predetermined closing engagement with the port means. In 
a practical and unique embodiment of this invention, the web spring is 
clamped about the periphery with the sealing disc located between a power 
or supply orifice and an exhaust orifice and located in engagement with 
one of the orifices. A rigid magnetic member is secured to the backside of 
the spring disc to form a functioning part of the electromagnetic unit. 
The electromagnetic coil may be wound about the exhaust port and is 
operable when energized to create a magnetic field which magnetically 
attracts the spring and particularly the central disc portion and magnetic 
member. This reverses the position of the disc and the connection of the 
output port, such as to open the supply port while closing the exhaust 
port, and permitting a relatively high pressure flow through the valve 
unit. A very slight deflection is required while establishing the desired 
return spring force. Further, the web-like disc or spider spring creates a 
relatively small mass which, in combination with the small deflection, 
provides relatively rapid response with low power consumption to provide a 
true snap-action response. This, of course, adapts the unit to low voltage 
application and to solid state control systems. For example, when the 
magnetic force applied by the electromagnet reaches a selected level, a 
magnetic field of sufficient strength to move the web spring is created. 
The initial movement of the web spring shortens the air gap and thus 
provides snap action movement of the spring in the direction of the 
electromagnet. This establishes a free-flow path through the valve. As 
soon as the excitation decreases below a selected magnetic holding force, 
the spring initiates movement to the close position. The slight increase 
in the gap length accelerates and, of course, reduces, increasing the 
holding force and the net effect is a reverse snap action closing of the 
valve. 
Generally, in accordance with a preferred and unique feature and 
construction of the present invention, a web-like spring is formed from a 
suitable spring material which may be of a magnetic or non-magnetic 
material. The continuous central portion may be coated with a thin layer 
of sealant such as silicon rubber. The web spring is clamped about its 
periphery within a cup-shaped valve body having a centrally located port 
having a flat end face. The valve body is closed by an electromagnetic 
assembly sealed to the open end of the valve body or unit. The port end 
face is located with respect to the clamping means to stress the arms and 
create a firm seating of the spring disc on the end face to create seal 
with essentially zero leakage. A rigid magnetic member is secured to the 
back of the spring disc and creates a constant working air gap to the 
electromagnetic assembly. 
The electromagnetic assembly in a unique construction is formed with an 
E-shaped magnetic core having three legs of essentially equal length and 
with a slightly protruding central leg aligned with the center of the 
spring. The exhaust port is formed within the central leg. The magnetic 
pad is provided on the backside of the spring and is spaced slightly from 
the E-shaped core to define a short working gap between the core and the 
pad. The pad provides a relatively large cross-sectional flux path and 
contributes to the rapid snap action response of the system. This 
construction is particularly significant in producing a highly 
satisfactory binary logic signal particularly adapted for fluidic systems. 
Further, in accordance with a further significant aspect of the present 
invention, the housing elements are formed as extruded plastic, including 
the generally cup-shaped base member having a centrally located port and 
an outer annular plastic ring clamping the spring against a clamping ledge 
of the base member. The electromagnetic unit includes a plastic support 
housing adjustably mounted within the ring for locating of the core 
relative to the pad and spring. 
Applicants have found that the present invention in the optimum 
construction of flat spring and disc magnetic members provides an improved 
snap action response with the pressure essentially varying instantaneously 
between the supply pressure and zero or reference on the output side. 
The present invention provides a simple, reliable and effective electric to 
fluid signal transducer or valve unit which is particularly adapted to 
commercial production.

DESCRIPTION OF THE ILLUSTRATED EMBODIMENT 
Referring to the drawings and particularly to FIG. 1, a piston operator 1 
is shown coupled to position a load device 2. The piston operator 1 is 
connected to a suitable fluid source 3, shown as a pneumatic supply, by an 
electro-responsive fluid valve unit 4 constructed in accordance with the 
present invention. The valve unit 4 includes an electric actuator 5 
coupled to a 3-way valve 6 having an input port 7 connected to the supply 
3, an output port 8 connected to operator 1 and an exhaust port 9. A 
digital signal source or sensor means 10 of any suitable construction is 
connected to the actuator 5. The actuator 5 positions the valve 6 to 
connect the piston operator to full supply pressure of source 3 or to 
exhaust and thereby creates a full on or full off positioning of the load 
device 2. 
The present invention is particularly directed to the construction of a 
novel electric to fulid valve unit 4 which may be employed in any fulid 
signalling system and is particularly adapted in its preferred 
construction to incorporation into a binary logic fluidic control system. 
Referring particularly to FIG. 3, illustrated valve 6 of the present 
invention is generally a diaphragm type operator with the input port 7 
terminating within a chamber 11. The output port 8 provides an output 
connection from the load chamber 11. The port 7 is normally closed by a 
web disc spring unit 12. The electric actuator 5 is an electromagnetic 
type and is secured to the opposite side of the web spring unit 12. The 
actuator includes an operating coil 13 connected to signal sensor 10. When 
energized, a magnetic field 14 is created, attracts the web spring unit 12 
opening the port 7 and permitting transfer of fluid pressure to the output 
port 8 and, thus, to the piston operator 1. In the de-energized state, the 
web spring unit 12 closes the port 7. The exhaust port 9 serves to exhaust 
the fluid trapped between the piston operator 1 and the now closed port 7, 
which resets the standby position. 
Thus in the illustrated embodiment of the invention, the electromagnetic 
unit acts as a two-way valve for controlled alternate positioning of the 
piston operator 1. 
More particularly, in the illustrated embodiment of the invention, the 
valve unit 4 includes a generally cup-shaped base member 15 having the 
input port 7 in the form of a nozzle integrally located centrally of the 
base wall 15a. The port 7 includes an orifice 16 which terminates in a 
flat inner wall 17. 
The web spring unit 12 overlies the wall 17 and, in particular, includes a 
spring member 18 having an outer peripheral portion 19 fixed to the 
cup-shaped base member 15. An annular clamping member 20 is press-fitted 
or otherwise firmly secured within the cup-shaped member 14 and abuts the 
peripheral portion 18 of spring unit 12 to firmly clamp the unit within 
the housing. 
As more clearly shown in FIG. 4, the spring member 18 of spring unit 12 is 
a generally flat, circular metal spring having the outer peripheral 
portion 19 connected by a plurality of similar spider spring arms 21 to a 
central sealing disc 22. Each of the arms 21 is similarly constructed with 
a short, radial portion 23 connected to the clamping ring portion 19, an 
arm portion curving circumferentially and inwardly toward a central 
sealing disc 22 and being joined thereto by generally short, radial 
portion 24. The arms 21 are equicircumferentially spaced about the disc 
and each spans slightly less than one-third of the total circumferential 
dimension of the disc 22. 
As shown in FIG. 3, the web spring 18 is mounted under tension by 
offsetting of the plane of clamping ledge 25 in the base member 15 with 
respect to the flat end face or wall 17 of the port 7. Thus, the spring 
arms 21 are deflected and placed in tension. The central disc 22 firmly 
engages the flat face 17 of the nozzle 7 and establishes a firm, reliable, 
leakproof sealing of the source connection. 
A rigid pad 26 of suitable magnetic material, such as iron, is secured to 
the opposite side of the disc 22 and projects radially, outwardly 
therefrom. The magnetic pad 26 maintains a relative parallel positioning 
as a result of its self-supporting rigid condition and defines a flat 
plate-like member to the backside of spring unit 12 and forming a part of 
the electromagnetic unit 5. 
In the illustrated embodiment of the invention, the electromagnetic unit 5 
includes an inverted cup-shaped coil holder 27 which is adjustably mounted 
within the annular clamping member, as by a threaded connection 28. The 
threaded connection 28, while adjustable, provides a fluid-tight joint. An 
E-shaped iron core 29 is supported within the coil holder 27 with the 
three legs or arms projecting from a base portion to the open end of the 
coil holder. The central leg 30 protrudes slightly from holder 27 and the 
exhaust opening 9 extends through the leg and the base of the coil holder 
27. The exhaust opening is thus aligned centrally of the valve unit 4, and 
with the orifice 16 closed, provides for exhaust of fluid from the chamber 
11 and operator 1. The operating coil 13 is wound about the central leg 30 
of the E-shaped core 29. When the coil 13 is excited, the magnetic field 
14 is created within the central leg 30 and extends to the opposite sides, 
passing through the base position and each of the outer legs 31 and 
returning through the iron pad 26 and the air gaps 32 between the outer 
legs 31 and the iron pad 26. The magnetic field, shown by lines 14, 
attracts the iron pad 26 to the E-core 29. 
The magnetic field force must rise to some level dependent on the mass and 
on the spring characteristic of the spring arms 21 to initiate movement of 
the spring unit 12. When sufficient voltage is applied to the coil 13 to 
initiate such movement, the air gaps 32 will shorten slightly, thereby 
reducing the magnetic force required to further move the spring unit 12. 
Consequently, the web spring unit 12 moves with a snap action, rapidly 
opening the input port 7 and supplying full pressure to the piston 
operator 1. Simultaneously, pad 26 abuts and engages the inner end of leg 
30 to close the exhaust passageway or port 9. The supply pressure source 3 
rapidly builds within the chamber 11 and is transmitted to the operator 1. 
Chamber 11 may be relatively small such that a practical, instantaneous, 
full pressure is transmitted to operator 1. As the excitation level of the 
signal to the coil decreases, the web spring unit 12 holds the valve open 
as the zero or minimal air gap 32 between the iron pad 26 and the core 29 
requires a small holding force. When the intensity of the magnetic field 
drops to selected level, the spring force is such as to overcome the 
magnetic force. The iron pad 26 then moves slightly from the ends of the 
core legs 31. The air gap 32 increases the required magnetic force to 
maintain balance. As a result, the spring force dominates and the web 
spring unit 12 snaps to close the orifice 16, thereby cutting off the 
pressure supply and simultaneously opening the exhaust port 9 to establish 
a reference or zero pressure supply to the piston operator 1. 
The above characteristic of the valve unit 12 is diagrammatically 
represented in FIG. 5 in which the output pressure switches between 
reference or zero and supply pressure at a selected direct current signal 
voltage, of either polarity. 
Applicants have found that the structure can be made exceedingly small. For 
example, in a practical embodiment, the valve unit 4 had a diameter on the 
order of 0.875 inches and a total depth between the base of the cup-shaped 
valve body member 14 and the electro-coil holder 27 on the order of 1.187 
inches and a gap on the order of 0.06 inches. 
As illustrated in the preferred embodiment of the invention, the web spring 
18 is mounted under tension as shown in FIG. 3. Both the spring 18 and the 
iron pad 26 are preferably also provided with outer, exterior faces of a 
suitable sealant such as a silicone rubber 17. This establishes a highly 
reliable and positive sealing of the input orifice 16 of the input port 7, 
resulting in zero leakage while maintaining a rapid response to an 
electrical signal. The use of the central, parallel sealing portion or 
disc 22 with the rigid pad 26 creates a firm closure such that a highly 
effective fluid seal of the, respective, orifices or ports is created. 
The non-magnetic or magnetic spring 18, in combination with the auxiliary 
iron pad 26, provides a highly efficient spring and magnetic system. The 
thin spring 18 is selected of a material and thickness to create the 
desired spring characteristic and snap action response. 
In the preferred construction, the web spring is formed as a flat member of 
a thin, non-magnetic material, such as beryllium copper and which may be 
0.005 inches in thickness. This will provide the desired spring 
characteristics. A flat spring member is also readily adapted to suitable 
conventional manufacturing techniques. The pad 26 is selected of a 
material and thickness to create a highly efficient and desired magnetic 
path for producing accurate and positive response of the system. 
Further, by manufacturing the valve unit 4 with plastic body or housing 
portions, simple, reliable and inexpensive elements are formed which can 
be readily mass produced. The simplicity of the components and system also 
contributes to a minimal cost with mass production techniques and provides 
a device which is highly practical for commercial usage as an interface 
device in fluidic systems and the like. 
The present invention thus provides an improved, miniaturized electrical to 
pressure transducing valve unit which can operate with low power 
consumption, produce digital or on-off fluidic signals in response to a 
corresponding low-powered electrical digital signal. 
Various modes of carrying out the invention are contemplated as being 
within the scope of the following claims, particularly pointing out and 
distinctly claiming the subject matter which is regarded as the invention.