Electromagnetically actuated fluidic valves and switches

Abstract

The absence of high efficiency, compact fluidic pumps has until recently blocked the consideration of using hydraulic devices within portable and/or alkaline battery powered consumer and non-consumer products. The higher the functionality and programmability desired for a consumer and/or non-consumer product exploiting a fluidic pump then the more complex the overall fluidic system in terms of the number of actuators, valves, switches etc. within the fluidic system coupled to the one or more fluidic pumps. Accordingly, there exists a requirement to provide compact fluidic valves and switches to support configurability, programmability, and operation of these portable battery-operated consumer and non-consumer devices in conjunction with these newly available high efficiency, compact fluidic pumps. Such fluidic valves and switches should offer high efficiency, have a small footprint, be low complexity for high reliability and ease of manufacture, and low cost.

What is claimed is: 
     
         1 . A fluidic device comprising:
 a piston comprising at least a core formed from a first magnetic material having a first length and a first predetermined lateral dimension;   a piston sleeve formed from a first predetermined non-magnetic material having an inner bore having a predetermined tolerance with respect to the first predetermined lateral dimension of the piston, an outer profile of a second predetermined lateral dimension, and a second length;   at least an electrical coil of a plurality of electrical coils, each electrical coil with an inner bore having a predetermined tolerance with respect to the second predetermined lateral dimension, a fourth length, and disposed at a predetermined position relative to the piston sleeve in dependence upon at least the lengths of the piston sleeve and piston;   a pair of magnetic washers formed from a second predetermined magnetic material each having a second thickness and having a central opening, wherein each magnetic washer is disposed at one end of the piston sleeve; and   a pair of non-magnetic washers formed from at least a third predetermined non-magnetic material having an outer portion, an inner portion, and comprising a pair of openings through at least the outer portion of the non-magnetic washer, wherein the pair of openings are disposed either side of a radial axis of the non-magnetic washer and each non-magnetic washer is disposed externally to one of the magnetic washers such that a surface of the outer portion is in contact with the magnetic washer and the inner portion projects through the magnetic washer towards the middle of the piston sleeve and limits motion of the piston within the piston sleeve;   wherein   in a first configuration the piston is retained against the inner portion of the non-magnetic washer at one end of the piston sleeve by magnetic attraction to the magnetic washer at that end of the piston sleeve thereby blocking fluid flow through the pair of openings at that end of the piston sleeve but allowing fluid flow through the pair of openings at the other distal end of the piston sleeve;   in a second configuration the piston is retained against the inner portion of the non-magnetic washer at the other distal end of the piston sleeve by magnetic attraction to the magnetic washer at that distal end of the piston sleeve thereby blocking fluid flow through the pair of openings at that distal end of the piston sleeve but allowing fluid flow through the pair of openings via at the other end of the piston sleeve; and   the piston is moved to establish either of the first configuration and the second configuration by selective electrical excitation of the at least one electrical coil of the plurality of electrical coils.   
     
     
         2 . The fluidic device according to  claim 1 , wherein
 the retention force between a magnetic washer and the piston in either of the first and second configurations is determined in dependence upon the distance that the inner portion projects through the magnetic washer towards the middle of the piston sleeve.   
     
     
         3 . The fluidic device according to  claim 1 , wherein
 the inner portion comprises an outer ring and a central divider thereby providing that portion of the pair of openings through the inner portion;   the remainder of the pair of openings are through the outer portion; and   the piston engages at least the central divider of the inner portion.   
     
     
         4 . The fluidic device according to  claim 3 , wherein
 either:
 the outer ring and central divider both project the same distance into the bore of the fluidic device; 
   or
 the central divider projects further into the bore of the fluidic device than the outer ring. 
   
     
     
         5 . The fluidic device according to  claim 1 , wherein
 the inner portion comprises a central divider thereby dividing the bore of the piston sleeve into two regions which are each fluidically coupled to one opening of the pair of openings;   the pair of openings are through the outer portion; and   the piston engages the central divider of the inner portion.   
     
     
         6 . The fluidic device according to  claim 1 , wherein
 the core forms the entire piston;   the first magnetic material has a first elastic modulus;   the third predetermined non-magnetic material has a second elastic modulus lower than the first elastic modulus.   
     
     
         7 . The fluidic device according to  claim 1 , wherein
 the piston comprises a pair of end caps at either end of the piston with the core between them;   the pair of end caps are formed from a material having a first elastic modulus;   the third predetermined non-magnetic material has a second elastic modulus either lower than or higher than the first elastic modulus.   
     
     
         8 . The fluidic device according to  claim 1 , wherein
 the core forms the entire piston;   the first magnetic material has a first elastic modulus;   each non-magnetic washer comprises the outer portion and a first predetermined portion of the inner portion formed from the predetermined non-magnetic material;   the remainder of the inner portion of each non-magnetic washer forms the surface against which the piston abuts and is formed from another predetermined non-magnetic material having a second elastic modulus lower than the first elastic modulus.   
     
     
         9 . The fluidic device according to  claim 1 , wherein
 the piston comprises a pair of end caps at either end of the piston with the core between them;   the pair of end caps are formed from a material having a first elastic modulus;   each non-magnetic washer comprises the outer portion and a first predetermined portion of the inner portion formed from the predetermined non-magnetic material;   the remainder of the inner portion of each non-magnetic washer forms the surface against which the piston abuts and is formed from another predetermined non-magnetic material having a second elastic modulus either lower than or higher than the first elastic modulus.   
     
     
         10 . The fluidic device according to  claim 1 , wherein
 the piston further comprises N projections along its outer surface along its length;   the piston sleeve further comprises N grooves along its inner surface along its length; and   the piston is inserted into the piston sleeve such that N projections are engaged within the N grooves thereby restricting rotation of the piston within the piston sleeve and defining an orientation of the piston to the piston sleeve.   
     
     
         11 . The fluidic device according to  claim 10 , wherein
 either an end of the piston comprises or both ends of the piston comprise a pair of projections which are aligned with the pair of openings; and   the pair of projections engage and disengage with the pair of openings when the piston is driven into contact with and out of contact with the non-magnetic washer.   
     
     
         12 . A fluidic device comprising:
 a piston having a first length and a first predetermined lateral dimension comprising a core formed from a first magnetic material and a pair of end caps formed from a first predetermined non-magnetic material;   a piston sleeve formed from a first predetermined non-magnetic material having an inner bore having a predetermined tolerance with respect to the first predetermined lateral dimension of the piston, an outer profile of a second predetermined lateral dimension, and a second length;   at least an electrical coil of a plurality of electrical coils, each electrical coil with an inner bore having a predetermined tolerance with respect to the second predetermined lateral dimension, a fourth length, and disposed at a predetermined position relative to the piston sleeve in dependence upon at least the lengths of the piston sleeve and piston;   a pair of magnetic washers formed from a second predetermined magnetic material each having a second thickness and having a central opening, wherein each magnetic washer is disposed at one end of the piston sleeve; and   a pair of non-magnetic washers formed from at least a second predetermined non-magnetic material having an outer portion, an inner portion, and comprising a pair of openings through at least the outer portion of the non-magnetic washer, wherein the pair of openings are disposed either side of a radial axis of the non-magnetic washer and each non-magnetic washer is disposed externally to one of the magnetic washers such that a surface of the outer portion is in contact with the magnetic washer and the inner portion projects through the magnetic washer towards the middle of the piston sleeve and limits motion of the piston within the piston sleeve;   wherein   in a first configuration the piston is retained against the inner portion of the non-magnetic washer at one end of the piston sleeve by magnetic attraction to the magnetic washer at that end of the piston sleeve thereby blocking fluid flow through the pair of openings at that end of the piston sleeve but allowing fluid flow through the pair of openings at the other distal end of the piston sleeve;   in a second configuration the piston is retained against the inner portion of the non-magnetic washer at the other distal end of the piston sleeve by magnetic attraction to the magnetic washer at that distal end of the piston sleeve thereby blocking fluid flow through the pair of openings at that distal end of the piston sleeve but allowing fluid flow through the pair of openings via at the other end of the piston sleeve; and   the piston is moved to establish either of the first configuration and the second configuration by selective electrical excitation of the at least one electrical coil of the plurality of electrical coils.   
     
     
         13 . The fluidic device according to  claim 12 , wherein
 the retention force between a magnetic washer and the piston in either of the first and second configurations is determined in dependence upon the thickness of the end cap at the respective end of the piston.   
     
     
         14 . The fluidic device according to  claim 12 , wherein
 the inner portion comprises an outer ring and a central divider thereby providing that portion of the pair of openings through the inner portion;   the remainder of the pair of openings are through the outer portion; and   the piston engages at least the central divider of the inner portion.   
     
     
         15 . The fluidic device according to  claim 14 , wherein
 either:
 the outer ring and central divider both project the same distance into the bore of the fluidic device; 
   or
 the central divider projects further into the bore of the fluidic device than the outer ring. 
   
     
     
         16 . The fluidic device according to  claim 12 , wherein
 the inner portion comprises a central divider thereby dividing the bore of the piston sleeve into two regions which are each fluidically coupled to one opening of the pair of openings;   the pair of openings are through the outer portion; and   the piston engages the central divider of the inner portion.   
     
     
         17 . The fluidic device according to  claim 12 , wherein
 the pair of end caps are formed from a material having a first elastic modulus; and   the second predetermined non-magnetic material has a second elastic modulus either lower than or higher than the first elastic modulus.   
     
     
         18 . The fluidic device according to  claim 12 , wherein
 the pair of end caps are formed from a material having a first elastic modulus;   each non-magnetic washer comprises the outer portion and a first predetermined portion of the inner portion formed from the second predetermined non-magnetic material;   the remainder of the inner portion of each non-magnetic washer forms the surface against which the piston abuts and is formed from another predetermined non-magnetic material having a second elastic modulus either lower than or higher than the first elastic modulus.   
     
     
         19 . The fluidic device according to  claim 12 , wherein
 each end cap further comprises N projections along its outer surface along its length;   the piston sleeve further comprises N grooves along its inner surface along its length; and   the piston is inserted into the piston sleeve such that N projections are engaged within the N grooves thereby restricting rotation of the piston within the piston sleeve and defining an orientation of the piston to the piston sleeve.   
     
     
         20 . The fluidic device according to  claim 19 , wherein
 either an end cap of the piston comprises or both end caps of the piston comprise a pair of projections which are aligned with the pair of openings; and   the pair of projections engage and disengage with the pair of openings when the piston is driven into contact with and out of contact with the non-magnetic washer.   
     
     
         21 . A fluidic device comprising:
 a piston comprising at least a core formed from a first magnetic material having a first length and a first predetermined lateral dimension;   a piston sleeve formed from a first predetermined non-magnetic material having an inner bore having a predetermined tolerance with respect to the first predetermined lateral dimension of the piston, an outer profile of a second predetermined lateral dimension, and a second length;   at least an electrical coil of a plurality of electrical coils, each electrical coil with an inner bore having a predetermined tolerance with respect to the second predetermined lateral dimension, a fourth length, and disposed at a predetermined position relative to the piston sleeve in dependence upon at least the lengths of the piston sleeve and piston;   a pair of magnetic washers formed from a second predetermined magnetic material each having a second thickness and having a central opening, wherein each magnetic washer is disposed at one end of the piston sleeve;   a first body disposed at one end of the piston sleeve formed from at least a third predetermined non-magnetic material having an outer portion, an inner portion, and defining a pair of openings through at least the outer portion of the non-magnetic washer, wherein the pair of openings are disposed either side of a radial axis of the piston sleeve, the outer portion has a first surface disposed towards the external surface of the magnetic washer at that end of the piston sleeve, and the inner portion projects through the magnetic washer towards the middle of the piston sleeve and limits motion of the piston within the piston sleeve; and   a second body disposed at the other end of the piston sleeve formed from at least a fourth predetermined non-magnetic material having an outer portion, an inner portion, and defining a pair of openings through at least the outer portion of the non-magnetic washer, wherein the pair of openings are disposed either side of a radial axis of the piston sleeve, the outer portion has a first surface disposed towards the external surface of the magnetic washer at that end of the piston sleeve, and the inner portion projects through the magnetic washer towards the middle of the piston sleeve and limits motion of the piston within the piston sleeve;   wherein   in a first configuration the piston is retained against the inner portion of the non-magnetic washer at one end of the piston sleeve by magnetic attraction to the magnetic washer at that end of the piston sleeve thereby blocking fluid flow through the pair of openings at that end of the piston sleeve but allowing fluid flow through the pair of openings at the other distal end of the piston sleeve;   in a second configuration the piston is retained against the inner portion of the non-magnetic washer at the other distal end of the piston sleeve by magnetic attraction to the magnetic washer at that distal end of the piston sleeve thereby blocking fluid flow through the pair of openings at that distal end of the piston sleeve but allowing fluid flow through the pair of openings via at the other end of the piston sleeve;   the piston is moved to establish either of the first configuration and the second configuration by selective electrical excitation of the at least one electrical coil of the plurality of electrical coils; and   the first body and second body provide at least one of fluidic channels through which fluid flows to and from the openings at either end of the fluidic device and part of at least one of a scaffold and casing of a device of which the fluidic device forms part.   
     
     
         22 . The fluidic device according to  claim 21 , wherein
 the retention force between a magnetic washer and the piston in either of the first and second configurations is determined in dependence upon the distance that the inner portion projects through the magnetic washer towards the middle of the piston sleeve.   
     
     
         23 . The fluidic device according to  claim 21 , wherein
 the inner portion comprises an outer ring and a central divider thereby providing that portion of the pair of openings through the inner portion;   the remainder of the pair of openings are through the outer portion; and   the piston engages at least the central divider of the inner portion.   
     
     
         24 . The fluidic device according to  claim 23 , wherein
 either:
 the outer ring and central divider both project the same distance into the bore of the fluidic device; 
   or
 the central divider projects further into the bore of the fluidic device than the outer ring. 
   
     
     
         25 . The fluidic device according to  claim 21 , wherein
 the inner portion comprises a central divider thereby dividing the bore of the piston sleeve into two regions which are each fluidically coupled to one opening of the pair of openings;   the pair of openings are through the outer portion; and   the piston engages the central divider of the inner portion.   
     
     
         26 . The fluidic device according to  claim 21 , wherein
 the core forms the entire piston;   the first magnetic material has a first elastic modulus;   the third predetermined non-magnetic material has a second elastic modulus lower than the first elastic modulus; and   the fourth predetermined non-magnetic material has a second elastic modulus lower than the first elastic modulus.   
     
     
         27 . The fluidic device according to  claim 21 , wherein
 the piston comprises a pair of end caps at either end of the piston with the core between them;   the pair of end caps are formed from a material having a first elastic modulus;   the third predetermined non-magnetic material has a second elastic modulus either lower than or higher than the first elastic modulus; and   the fourth predetermined non-magnetic material has a second elastic modulus lower than the first elastic modulus.   
     
     
         28 . The fluidic device according to  claim 21 , wherein
 the core forms the entire piston;   the first magnetic material has a first elastic modulus;   the outer portion and a first predetermined portion of the inner portion of the first body are formed from the third predetermined non-magnetic material;   the outer portion and a first predetermined portion of the inner portion of the second body are formed from the fourth predetermined non-magnetic material;   the remainder of the inner portion of the first body forms the surface against which the piston abuts and is formed from a fifth predetermined non-magnetic material having a second elastic modulus lower than the first elastic modulus; and   the remainder of the inner portion of the second body forms the surface against which the piston abuts and is formed from a sixth predetermined non-magnetic material having a third elastic modulus lower than the first elastic modulus.   
     
     
         29 . The fluidic device according to  claim 1 , wherein
 the piston comprises a pair of end caps at either end of the piston with the core between them;   the pair of end caps are formed from a material having a first elastic modulus;   the outer portion and a first predetermined portion of the inner portion of the first body are formed from the third predetermined non-magnetic material;   the outer portion and a first predetermined portion of the inner portion of the second body are formed from the fourth predetermined non-magnetic material;   the remainder of the inner portion of the first body forms the surface against which the piston abuts and is formed from a fifth predetermined non-magnetic material having a second elastic modulus lower than or higher than the first elastic modulus; and   the remainder of the inner portion of the second body forms the surface against which the piston abuts and is formed from a sixth predetermined non-magnetic material having a third elastic modulus lower than or higher than the first elastic modulus.   
     
     
         30 . The fluidic device according to  claim 21 , wherein
 the piston further comprises N projections along its outer surface along its length;   the piston sleeve further comprises N grooves along its inner surface along its length; and   the piston is inserted into the piston sleeve such that N projections are engaged within the N grooves thereby restricting rotation of the piston within the piston sleeve and defining an orientation of the piston to the piston sleeve.   
     
     
         31 . The fluidic device according to  claim 30 , wherein
 either an end of the piston comprises or both ends of the piston comprise a pair of projections which are aligned with the pair of openings; and   the pair of projections engage and disengage with the pair of openings when the piston is driven into contact with and out of contact with the non-magnetic washer.   
     
     
         32 . The fluidic device according to  claim 1 , wherein
 the piston has a cross-section which is non-circular;   the piston sleeve has the same non-circular cross-section; and   the non-circular cross-section of the piston and piston sleeve thereby restricts rotation of the piston within the piston sleeve and defines an orientation of the piston to the piston sleeve.   
     
     
         33 . The fluidic device according to  claim 12 , wherein
 the piston has a cross-section which is non-circular;   the piston sleeve has the same non-circular cross-section; and   the non-circular cross-section of the piston and piston sleeve thereby restricts rotation of the piston within the piston sleeve and defines an orientation of the piston to the piston sleeve.   
     
     
         34 . The fluidic device according to  claim 21 , wherein
 the piston has a cross-section which is non-circular;   the piston sleeve has the same non-circular cross-section; and   the non-circular cross-section of the piston and piston sleeve thereby restricts rotation of the piston within the piston sleeve and defines an orientation of the piston to the piston sleeve.   
     
     
         35 . The fluidic device according to  claim 1 , wherein
 the distance that the inner portion of each non-magnetic washer projects through the magnetic washer towards the middle of the piston sleeve is the same on each end of the fluidic device;   the latching force of the piston at one end of the fluidic device is established in dependence upon a first inner diameter of the magnetic washer and a first thickness of the magnetic washer at that end of the fluidic device; and   the latching force of the piston at the other end of the fluidic device is established in dependence upon at least one of a second inner diameter of the magnetic washer at the other end of the fluidic device, a second thickness of the magnetic washer at the other end of the fluidic device, and the magnetic washer at the other end of the fluidic device being formed from a third predetermined magnetic material providing a different magnetic field strength than the second predetermined magnetic material.   
     
     
         36 . The fluidic device according to  claim 12 , wherein
 the distance that the inner portion of each non-magnetic washer projects through the magnetic washer towards the middle of the piston sleeve is the same on each end of the fluidic device;   the latching force of the piston at one end of the fluidic device is established in dependence upon a first inner diameter of the magnetic washer and a first thickness of the magnetic washer at that end of the fluidic device; and   the latching force of the piston at the other end of the fluidic device is established in dependence upon at least one of a second inner diameter of the magnetic washer at the other end of the fluidic device, a second thickness of the magnetic washer at the other end of the fluidic device, and the magnetic washer at the other end of the fluidic device being formed from a third predetermined magnetic material providing a different magnetic field strength than the second predetermined magnetic material.   
     
     
         37 . The fluidic device according to  claim 21 , wherein
 the distance that the inner portion of each of the first body and the second body through each of the magnetic washers towards the middle of the piston sleeve is the same on each end of the fluidic device;   the latching force of the piston at the end of the fluidic device with the first body is established in dependence upon a first inner diameter of the magnetic washer and a first thickness of the magnetic washer at that end of the fluidic device; and   the latching force of the piston at the other end of the fluidic device is established in dependence upon at least one of a second inner diameter of the magnetic washer at the other end of the fluidic device, a second thickness of the magnetic washer at the other end of the fluidic device, and the magnetic washer at the other end of the fluidic device being formed from a third predetermined magnetic material providing a different magnetic field strength than the second predetermined magnetic material.