`P813-7009
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`
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`THE COMMISSIONER OF PATENTS AND TRADEMARKS——November_—__ate81997
`Washington, D.C. 20231
`
`Sir;
`
`Transmitted herewith forfiling is the patent application of
`Inventor(s): Satoshi NAKAYAMA; Yoshie WATARI: Takahiro KURIHARA
`
`For;
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`FLOW CONTROLVALVE
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`Specification (24 pages)
`XX
`XX=13. sheets of drawings
`-
`Declaration and Powerof Attorney
`_
`An assignment of the invention to
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`(Col. 2)
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`
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`Other Than A
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`with accompanying PTO-1595 Form.
`XX_Information Disclosure Statement; PTO-1449 Form: References (3)
`=XX
`A filing fee, calculated as shownbelow:
`
`aa
` (Col. 1)
`
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`4 FOR:
`No.Filed
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`fromctams[isos[0_|
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`Small Entity
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`Hi
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`XX
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`NO FEE ENCLOSED.Thefilingfee will be submittedlater.
`
`Metropolitan Square
`655 15th Street, N. W.
`Suite 330 - G Street Lobby
`Washington, D. C. 20005-5701
`Tel: (202) 638-5000
`Fax: (202) 638-4810
`GEO/hk
`Enclosures:
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`Respectfully submitted,
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`-
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`NIKAIDO, MARMELSTEIN, MURRAY & ORAM LLP
`
`By: George E. Oram,Jr.
`Reg. No. 27,931
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`Specification and Claims/Drawings (13 sheets)
`Information Disclosure Statement/PTO-1449 Form/References(3)
`
`20 ‘d
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`‘ON XY
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`Wd L€:€0
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`CHM 86-81-@a4
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`FLOW CONTROL VALVE
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`SPECIFICATION
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`BACKGROUNDOF THE INVENTION
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`1. Fields of the Invention
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`The present invention is directed to a flow control valve, and more
`particularly to such a valve utilizing a shape memory alloy wire for
`varying a valve opening for regulation of a fluid flow.
`
`2. Description of the Prior Art
`U.S. Pat. No. 4, 973, 024 and Japanese Laid-Open Publication
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`(KOKAI) No. 2-8573 disclose prior art flow control valves using a shape
`memory alloy wire for regulating a fluid flow. The valve comprises a
`barrel with an axial bore, a valve seat in the axial bore, and a valve body
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`axially movable within the bore relative to the valve seat to vary a valve
`opening formed between the valve body and the valve seat.
`Formed
`within the barrel is an internal flow path extending from an inlet to an
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`outlet through the valve opening. The shape memory alloy wire
`bridges between the valve body andthe barrel and is connected to an
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`electrical source in order to be heated in a controlled manner,
`undergoing thermal deformation along its length. The deformation or
`varying length of the wire causes the valve body to move against a
`spring bias in a direction of increasing or decreasing the valve opening
`for regulation of the fluid flow..
`In this known valve, the wire extends
`within the axial bore of the barrel with its opposite ends connected
`respectively to the valve body and the barrel and therefore must be
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`20
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`connected to the electric source by way of the valve body as well as the
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`barrel. Thus, the valve body and the barrel are required to be made of
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`an electrically conductive material, which reduces design flexibility.
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`In
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`addition, the valve body and the barrel might form an additional
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`electrical path other than through wire or might fail to establish a
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`constant electrical path only through the wire not influenced by the
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`movementof the valve body.
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`In this event, the wire could be heated in
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`an uncontrolled manner so as to result in a failure of reliably regulating
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`the fluid flow.
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`Further, since the wire extends through the internal
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`fluid path, the wire will be thermally affected by the fluid passing
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`through the path so that the wire suffers from unintended thermal
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`deformation, which eventually leads to unreliable regulation of the fluid
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`flow.
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`These problems could be eliminated in a flow control valve
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`proposed in Japanese Laid-Open Publication (KOKAIT) No. 61-103081.
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`The valve comprises a barrel with an axial bore, a valve seat fixed in the
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`axial bore, and a valve body axially movable within the barrel to vary a
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`valve opening defined between the valve body and the valve seat. The
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`barrel is formed with an inlet and an outlet which are communicated
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`through the valve opening to establish an internal flow path within the
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`barrel. A like shape memory alloy wire is provided for connection of
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`the valve bodyto the barrel in order to vary the valve opening in
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`response to a controlled heating of the wire.
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`In this valve, the wire is
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`20
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`wound round a portion of the valve body andis physically fixed atits
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`opposite ends to the barrel, while the wire is electrically connected to an
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`electrical source through terminals at the opposite ends of the wire.
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`Thus, the wire can be directly connected to the electrical source without
`passing through the valve body andthe barrel, thereby assuring reliable
`control of regulating the fluid flow by the use of the wire. However,
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`25
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`there still remains a problem that the wire winding round the valve body
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`within the axial bore adds an extra axial length to a structure of the valve
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`body and the valve seat arranged axially along the barrel, which is a
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`
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`hindrance to give a fully-compacted design to the flow control valve
`using the shape memoryalloy wire. This size problem becomes more
`critical as the length of the wire is required to be greater for obtaining an
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`increased amount of linear deformation of the wire available for the
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`control of the valve opening.
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`SUMMARYOF THE INVENTION
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`In view of the above problems, the present invention has been
`
`achieved to provide an improved fluid control valve which could be
`made compact, while retaining a reliable fluid flow regulation by the use
`of a shape memoryalloy wire. The fluid control valve in accordance
`with the present invention comprises a barrel having an axial bore within
`which an internal flow path for a fluid is formed to extend from aninlet
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`to an outlet. A base memberis disposed at one-axial end of the barrel,
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`while a valve body is held in the other axial end of the barrel. The
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`valve body is cooperative with the base memberto define therebetween a
`valve opening in the course of the internal flow path. The valve body
`is axially movable towards and away from the base memberto vary the
`valve opening for regulating the flow ofthe fluid throughthe internal
`flow path. A bias spring is provided to urge the valve body for varying
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`the valve opening in one direction. At least one shape memory alloy
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`wire connects the valve bodyto the barrel to exert, in response to
`thermal deformation of the wire, a force of moving the valve body
`against the bias spring to vary the valve opening. The wire is formed
`on its opposite ends with terminals by which the wire is connected to an
`electrical source for heating the wire to give the thermal deformation.
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`The barrel is provided with at least one anchor member for engaging
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`with one end of the wire and the valve bodyis provided with at least one
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`catch memberfor engaging with other end of the wire. The anchor
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`member is disposed on the exterior of the barrel and at such a portion
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`that the wire stretches between the barrel and the valve body exteriorly
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`of the barrel in an overlapping relation with a major portion ofthe barrel
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`along the axial length thereof. Because of the abovespatial
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`arrangement of the anchor member, the wire can be kept substantially
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`away from the internal flow path formed within the barrel. Whereby,
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`the wire has a less chance of being exposedto the fluid flow and
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`consequently a less chance of being thermally affected by the fluid flow
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`10
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`so as to give a reliable regulation of the fluid flow based upon a
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`controlled thermal linear deformation of the wire.
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`Further, since the
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`wire overlaps with the major portion of the barrel along the axial length
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`thereof, the entire valve can have a reduced axial dimension and be
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`15
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`therefore made compact enoughto be installed in a limited space.
`Accordingly, it is a primary object of the present invention to
`provide a flow control valve which is capable ofrealizing a reliable
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`regulation of the fluid flow and at the same time of being made compact.
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`In a preferred embodimentof the present invention, the barrel is
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`provided with a pair of the anchor membersfor securing the opposite
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`20
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`ends of the wire, and the valve body is provided with a pair of the catch
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`members. The wire is wound round the catch members with the
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`opposite ends of the wire fixed to the anchor members. Thus, the wire
`can stretch over the valve body in an elongated length to give a
`correspondingly increased amount of linear deformation within a limited
`axial length of the barrel, thereby giving an increased range of
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`25
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`movementof the valve body pera limited temperature variation range.
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`It is therefore another object of the present invention to provide a
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`flow control valve which is capable of giving a wide range of controlling
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`the valve openingin relation to a limited temperature variation range.
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`The catch members is formed of a different material from the valve
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`body andis selected to have a thermal conductivity less than that of the
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`valve body. The catch membersproject from the valve body so that the
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`wire wound around the catch members is kept spaced from the valve
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`body. Thus, the wire is prevented from the leakage of the heat
`developed in the wire to the valve body, assuring a consistent control of
`thermally deforming the wire for reliable regulation of the fluid flow.
`Preferably, the base memberis threadedly engaged with the barrel
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`10
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`in order to vary an axial position of the base memberrelative to the
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`valve body for adjusting the valve opening.
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`A seal ring is attached to the valve body and comesinto tight
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`contact with the base memberto close the valve opening when the valve
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`body movesclose to the base member, thereby closing the valve opening
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`15
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`successfully.
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`In a preferred embodiment, the barrel is formed with a pair of wire
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`guides in addition to the anchor membersso that the wire is wound
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`round the guides as well as the catch members to extend around the
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`barrel and the valve body by one complete turn. Thus, the wire can
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`20
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`stretch in an elongated length for increasing the range of linear
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`deformation of the wire and therefore the range of varying the valve
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`opening even with the valve of the limited axial length.
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`A plurality of turnaround members may be formed on the valve
`body in addition to the anchor memberso that the wire passes round the
`turnaround members between the opposite ends thereof. The
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`25
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`turnaround membersare spaced circumferentially around the barrel.
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`With this result, the wire can be folded plural times in such manneras to
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`stretch axially and circumferentially of the barrel for elongating the
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`length of the wire to give a maximum range oflinear deformation to the
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`wire.
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`Further, the barrel may be formed with a retainer extension which
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`receives therearound the coil spring embodying the bias spring in such a
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`mannerasto isolate the coil spring from the base member threadedly
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`engaged with the barrel. The coil spring thus isolated from the base
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`memberis therefore kept intact from the axial movementof the base
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`member, thereby ensuring an easy adjustment of the valve opening
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`without varying a biasing force of spring.
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`The barrel may be formed in its outer surface with a groove for
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`passing therethrough the wire in order to protect the wire within the
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`barrel for reliable regulation of the fluid flow by the wire.
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`Further, the barrel may include a protective extension which
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`extends axially outwardly beyond the valve body for avoiding the valve
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`body from interfering with surroundings.
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`The valve may include a stopper for limiting a rotation of the valve
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`bodyrelative to the barrel about an axis of the barrel in order to prevent
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`the wire from being twisted or warped during the repeated movementof
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`the valve body, therefore ensuring a consistent flow control over a long
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` 10
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`20
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`period of use.
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`In addition, the valve may also include a restrictor which restricts
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`the axial movement of the valve body relative to the base member within
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`a predetermined range in order to prevent unduly high stress applied to
`the wire which would otherwise occur when the valve body is moved
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`25
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`away from the base member beyonda certain limit under the urgence of
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`the bias spring. Thus, the wire is protected from undergoing permanent
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`deformation due to such high stress applied in the absence of the
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`restrictor.
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`Preferably, the outlet is formed in the valve body and opensto the
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`exterior of the valve body at a portion staggered with the wire passing
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`over the valve body. The outlet communicates with the valve opening
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`through an axial path formed between the valve body and the barrel.
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`Thus, the wire can be intact from the fluid being discharged outward
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`through the outlet and can be therefore prevented from thermally
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`affected by the fluid flow.
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`These andstill other objects and advantageous features of the
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`present invention will become more apparent from the following
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`10
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`description of the preferred embodiments when taken in conjunction
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`with the attached drawings.
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`BRIEF DESCRIPTION OF THE DRAWINGS
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`FIG. 1 is an exploded perspective view of a flow control valve in
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`15
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`accordance with a first embodiment of the present invention;
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`FIG. 2 is a sectional view of the valve of FIG. 1;
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`FIG. 3 is a perspective view of a flow control valve in accordance with a
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`second embodiment of the present invention;
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`FIG. 4 is a perspective view of a flow control valve in accordance with a
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`20
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`third embodimentof the present invention;
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`FIG. 5 is an exploded perspective view of the valve of FIG.4;
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`FIG.6 is a perspective view of a flow control valve in accordance with a
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`fourth embodimentof the present invention;
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`FIG. 7 is an exploded perspective view of a flow control valve in
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`25
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`accordance with a fifth embodimentof the present invention;
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`FIG. 8 is a sectional view of the valve of FIG. 7;
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`FIG. 9 is a sectional view illustrating a modification of the above fluid
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`control valve;
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`FIG. 10 is an exploded perspective view of a flow control valve in
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`accordance with a sixth embodimentof the present invention;
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`FIG. 11 is a sectional view of the valve of FIG. 10;
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`FIG. 12 is a perspective view of the valve of FIG. 10; and
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`FIG. 13 is a sectional view of a fluid control valve in accordance with a
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`seventh embodimentof the present invention.
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`DETAILED DESCRIPTION OF THE EMBODIMENTS
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`A fluid control valve of the present invention is utilized in a device,
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`10
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`for example, a blood pressure monitoring device to discharge an air from
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`an occluding cuff at a controlled rate for determination of a systolic and
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`diastolic pressure.
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`First Embodiment <FIGS. 1 and 2>
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`Referring to FIGS. 1 and 2, there is shown a flow control valve in
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`15
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`accordance with a first embodiment of the present invention. The valve
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`comprises a barrel 10 of an electrical insulative plastic material having
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`an axial bore 11, a base member 20 in one end of an axial bore 11, and a
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`valve body 30 slidably fitted in the other end of the axial bore. The
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`base member20 is threadedly engaged with the interior of the barrel 10
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`20
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`to be capable of adjusting its axial position within the barrel 10, and is
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`formed integrally with a conduit 21 and a retainer extension 26
`extending axially in opposite directions with each other.
`Anorifice 22
`is formed centrally in the base member 20 and communicates with an
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`inlet 23 formed at the outer end of the conduit 21. The conduit 21 is
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`25
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`formed at its outer end with a slit 25 which is adapted in use to receive a
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`tool, i.e. a tip of a screwdriver for the axial adjustment of the base
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`member20.
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`The valve body 30 is in the form ofa shaft slidably received within
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`
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`a retainer extension 26 and is formed on its inner axial end with a stem
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`31 which projects into the orifice 22 of the base member20 to define,
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`between the stem and the base member, a valve opening which varies in
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`response to the axial movementof the valve body 30 relative to the base
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`member 20. The valve body 30 is formedin its outer surface with a set
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`of circumferentially spaced and axially elongated slits 32 which extend
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`from the valve opening to an outlet 34 formed between an end plate 33
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`and the adjacent end of the barrel 10. Thus, an internal flow path is
`formed to extend from theinlet 23 at the outer axial end of the base
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`10
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`member 20 through the valve opening to the outlet 34. The valve
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`member 30 is molded from anelectrically insulative plastic material to
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`integrally include the end plate 33 having a diameter greater than the
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`axial bore 11. A seal ring 46 is fitted around a foot of the stem 31 so as
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`to comesinto a tight contact with a valve seat formed on an inner axial
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`15
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`end of the base member 20 around the periphery of the orifice 22, when
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`the valve body 30 movesclose to the base member 20, thereby providing
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`a completely valve closed condition.
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`A coil spring 50 is fitted around the retainer extension 26 as being
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`compressed between the base member 20 and the end plate 33 of the
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`20
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`valve body 30 in order to bias the valve body 30 away from the base
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`member20, i.c., in a direction of increasing the valve opening for an
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`increased fluid flow through the flow path.
`In this sense, the valve is of
`anormally opentype. The valve body 30 is connectedto the barrel 10
`by means of wires 60 tightly stretched therebetween. The wire is made
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`25
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`of a shape memory alloy which has an original length and is deformed to
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`have a greater length so that it recovers to the original length when
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`heated. That is, the wire 60 will shrink when heated to thereby move
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`the valve body 30 inward against the bias of the spring 50 in a direction
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`of closing the valve opening. The shape memoryalloy is made of, for
`example, Ti-Ni, Ti-Ni-Cu, or Ti-Ni-Co. As best shown in FIG.2, each
`of the wires 60 is secured at its opposite ends to a pair of anchor
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`members 12 mounted onthe barrel 10 at one axial end adjacent the base
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`member 20 and spaced circumferentially by 180°, and is wound round a
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`pair of diametrically opposed catch members 35 formed at the periphery
`of the end plate 33 of the valve body 30. The anchor member 12 is in
`the form of a stud with a slit 14 in which the end of the wire 60 is fitted
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`and is staked therein.
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`In addition, the wire 60 is formedat its opposite
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`10
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`ends with terminals 61 for connection to an electrical source through a
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`control unit 70. The two wires 60 are connected in series by way ofa
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`conductor 62 across the electrical source to flow a current in a controlled
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`amount bythe control unit 70.
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`The control unit 70 includes a PWM controller to vary a duty ratio
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`15
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`of an electric current being fed to the wire 60 in order to control an
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`amount of Joule heat evolved in the wire and therefore a corresponding
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`amount of linear deformation of the wire for varying the valve opening,
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`i.e., the flow amountof the fluid through the valve.
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`In this embodiment,
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`the valve is controlled to decrease the flow amount continuously to the
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`20
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`entirely closed condition.
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`Each of the catch members35 is in the form of a pin extending
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`between a pair of brackets 36 integrally formed with the end plate 33 and
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`is made of a material having less thermal conductivity than the valve
`body 30 as well as having low coefficient of friction, for minimizing the
`heat transfer from the wire to the valve body as well as achieving smooth
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`25
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`engagement of the wire with the valve body. The end plate 33 is
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`formedin its outer surface with grooves 37 each communicatingat its
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`-11-
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`opposite ends to a concavity in which the pins 35 extend between the
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`brackets 36, so that each wire 60 passes through the grooves 37 in such a
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`manneras to be protected from contacting the surroundings, in addition
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`to being out of contact relation with the end plate 33.
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`It is noted here that the base member 20 may be moldedintegrally
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`with the barrel 10 to be a fixed member with respectto the barrel.
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`Second Embodiment <FIG. 3>
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`FIG. 3 illustrates a fluid control valve in accordance with a second
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`10
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`embodiment of the present invention whichis similar in construction and
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`operation to the first embodiment except that a single wire 60A is
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`employed to movethe valve body 30A. Like parts are designated by
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`like numerals with a suffix letter of “A”. The barrel 10A is formedat
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`its one axial end with a pair of diametrically spaced anchor members
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`15
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`12A each having twoslits, one being an anchorslit 14A for securing the
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`end of the wire and the other being a guide slit 15 for passing the wire
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`therethrough. The end plate 33A of the valve body is formed with a
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`corresponding set of diametrically spaced catch members 35A in the
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`form of pins. The single wire 60A winds round the pins 35A and also
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`20
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`the guide slits 15 so as to stretch around the barrel 10A and the valve
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`body by one complete turn. Thus, the wire can stretch in an elongated
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`length over the valve to give a corresponding increase amount of thermal
`deformation available for movement of the valve body.
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`25
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`Third Embodiment <FIGS. 4 and 5>
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`FIGS. 4 and 5 illustrate a fluid control valve in accordance with a
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`third embodiment of the present invention whichis similar to the second
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`embodiment exceptthat the single wire 60B is folded several times to
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`
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`-12-
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`extend circumferentially around the barrel 10B while stretching between
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`the barrel 10B and the valve body 30B. Like parts are designated by
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`like numerals with a suffix letter of “B”. The anchor member 12B
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`having twoslits 14B is provided on the barrel 10B at one axial end
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`adjacent to the end plate 33B of the valve body 30B for securing the
`opposite ends of the wire 60B at the respective slits 14B.
`In addition,
`the barrel 10B is formed with four main turnaround pins 17 at the axial
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`end away from the end plate 33B and with one auxiliary turnaround pin
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`18 at the other axial end adjacent the end plate 33B and diametrically
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`opposite of the anchor member 12B. The end plate 33B is formed with
`a pair of catch members in the form of pins 35B which are diametrically
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`opposed to each other and are angularly spaced by 90° aboutthe axis of
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`the barrel from the anchor member 12B and the pin 18. Thus, the wire
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`60B winds round the pins 35B of the end plate 33B as well as the
`turnaround pins 17 and 18 with the opposite ends fixed to the anchor
`member 12B. With this result, the wire can stretch between the barrel
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`and the valve body in an elongated length to thereby give a
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`correspondingly increased amount of linear deformation of the wire
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`available for controlling the valve opening.
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` 10
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`15
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`20
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`Fourth Embodiment <FIG. 6>
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`FIG.6 illustrates a fluid control valve in accordance with a fourth
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`embodimentof the present invention whichis similar to the third
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`embodiment exceptthat the single wire 60C extends doubly around the
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`25
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`barrel 10C. Like parts are designated by like numerals with a suffix
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`letter of “C”. The barrel 10C is formed with four main turnaround pins
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`17C projecting at one axial end away from the end plate 33C of the
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`-13-
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`valve body 30C and evenly spaced circumferentially around the barrel
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`10C and also with four auxiliary turnaround pins 18C projecting at the
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`other axial end adjacent the end plate 33C and evenly spaced
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`circumferentially around the barrel. All of the main turnaroundpins
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`17C and one auxiliary turnaround pin 18C are formed respectively with
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`double-channels each passing the wire 60C therethrough. The
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`remaining three of the auxiliary turnaround pin 18C is formed only with
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`a single channel andare referred to as single-channel pins. Thus, the
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`wire 60C starting from the anchor member 12C passes through in the
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`10
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`order of the inner channel of a first main pin 17C1, the first single-
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`channel auxiliary pin 18C1, inner channel of the second main pin 17C2,
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`inner channel of the second auxiliary pin 18C2, inner channel of the
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`third main pin 17C3, the third single-channel auxiliary pin 18C3, inner
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`channel of the fourth main pin 17C4, the fourth single-channel auxiliary
`pin 18C4, then the outer channel of the first main pin 17C1, the catch
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`15
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`member 35C of the end plate 33C, outer channel of the second main pin
`17C2, outer channel of the second auxiliary pin 18C2, outer channel of
`the third main pin 17C3, catch member 35C of the end plate 33C, and
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`the outer channel of the fourth main pin 17C4, and returns to the anchor
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`20
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`member 12C. With this elongated route, the wire 60C is given a
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`further increased amount of the linear expansion available for moving
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`the valve body 30C, thereby enhancing response sensitivity of the valve
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`opening relative to a limited range of the controlled temperature range
`for heating the wire.
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`25
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`Fifth Embodiment <FIGS. 7 and 8>
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`FIGS. 7 and 8 illustrate a fluid control valve in accordance with a
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`fourth embodimentof the present invention which is similar to the first
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`-14-
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`embodiment except that two wires 60D are utilized to connect the barrel
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`10D and the valve body 30D at the opposite ends of each wire. Like
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`parts are designated by like numerals with a suffix letter of “D”. To
`this end, the end plate 33D of the valve body 30D is formed with the
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`catch members 35D eachin the form of the stud with a slit 39 for
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`securing the one end of each wire 60D. Each wire 60D is formedatits
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`opposite ends with terminals 61D, one for connection with the electrical
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`source through the like control unit and the other for series connection
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`with the complementary wire 60D through a conductor 62D routed in a
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`10
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`like groove 37D in the outer surface of the end plate 33D.
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`In this
`
`embodiment and the other embodiments disclosed herein, the terminals
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`61D are configured to prevent the wire from disengaging from the
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`associated anchor members 12D when the wireis caused to shrink for
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`moving the valve body axially inward against the bias of the coil spring
`
`15
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`50.
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`Modification <FIG. 9>
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`FIG. 9 illustrates a modification of the first embodiment which is
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`similar to the first embodiment except that the orifice 22E is formed in
`
`20
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`the valve body 30E rather than in the base member 20E and the stem
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`31E projects on the base member 20Einto the orifice to define the gap
`
`opening therebetween. The orifice 22E communicates through the
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`conduit 21E in the valve body 30E with the inlet 23E at the outer end of
`the end plate 33E of the valve body 30E. Thus, the internal flow path
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`25
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`is formed from the inlet 23E through conduit 21E, orifice 22E, slit 32E
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`in the circumference of the valve body 30K,and to an outlet 34E
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`between the axial end of the barrel 10E and the end plate 33E. Like
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`parts are designated by like numerals with a suffix letter of “E”.
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`
`
`
`
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`-15-
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`Operation of the modified flow control vale is the sameasthat of the
`
`first embodiment and is deemed unnecessary to repeat herein.
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`Sixth Embodiment <FIGS. 10 to 12>
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`FIGS. 10 to 12 illustrate a fluid control valve in accordance with a
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`sixth embodiment of the present invention which is similar to the first
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`embodiment except that the single wire 60F is employed and concealed
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`in grooves 16 formed in the outer surface of the barrel 10F and that the
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`barrel 10F is integrally formed with a retainer extension 38 for receiving
`
`10
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`therearound the coil spring 50F and receiving therein the valve body 30F.
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`Like parts are designated by like numerals with a suffix letter of “F”.
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`The groove 16 extends substantially entire axial length of the barrel 10F
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`and communicates with the groove 37F in the end plate 33F so that the
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`wire 60F is received entirely within a concave notto interfere with
`
`15
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`external parts or components of a device in which the flow control valve
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`is installed. The wire 60F is wound round the like catch membersin
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`the form of pins 35F on the end plate 33F with the opposite ends of the
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`wire 60F secured to the like anchor members 12F on the barrel 10F.
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`The wire 60F is formed at its opposite ends with the like terminals 61F
`
`20
`
`for connection with the electric source through a like control unit 70F so
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`as to heat the wire in a controlled mannerfor regulation of the valve
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`opening.
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`Further, the barrel 10F includes a protective extension 19
`
`which extends axially beyond the end plate 33F of the valve body 30F
`for protecting the end plate 33F from interfering with the external parts
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`25
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`or components of the device.
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`In addition, the valve body 30F includes fingers 40 which extend
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`integrally from the end plate 33F into the groove 16 of the barrel 10F in
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`such a manneras to prevent the valve body 30F from rotating relative to
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`
`
`
`
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`-16 -
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`the barrel 10F about the axis thereof, thereby avoiding the otherwise
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`warping of the wire during the repeated movementof the valve body.
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`The fingers 40 are further formed with latches 41 which fit loosely in an
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`axially elongated recesses 42 in the outer surface of the barrel 10F in
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`order to restrict the axial movement of the valve body 10F. With the
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`engagementof the latches 41 to the one axial end of the recess 42, the
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`valve body 30F is protected from moving further axially outwardly by
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`the urgence of the spring 50F, thereby protecting the wire from suffering
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`undue force from the spring which would otherwise cause undesired
`
`10
`
`permanent deformation to the wire.
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`It is noted in this connection that
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`the like fingers 40 or equivalent members may be alternately formed on
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`the side of the barrel and are cooperative associated grooves or recess to
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`realize the above effect of preventing the relative rotation of the valve
`
`15
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`bodyto the barrel and of restricting the axial movement of the valve
`body.
`|
`In the present embodiment, the coil spring 50F fits around the
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`retainer extension 38 in an out of contact relation with the base member
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`20F, the coil spring 50F receives any external force when adjusting the
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`axial position of the base memberrelative to the valve body, thereby
`
`20
`
`giving a consistent biasing force not influenced from the varying
`
`position of the base memberforreliable control of the valve.
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`Further,
`
`the end plate 33F is formed with the outlets 34F which extend through
`the end plate in fluid communication respectively with the slits 32F in
`the outer surface of the valve body 30F to discharge the fluid mainly out
`
`25
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`of the outlets 34F. The outlets 34F are staggered, i.e., angularly spaced
`
`from the wire 60F passing through the groove 37F of the end plate 33F,
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`thereby minimizing the chance of exposing the wire 60F to the fluid
`
`flow. With this result, the wire 60F is kept thermally unaffected
`
`
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`-17-
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`substantially by the fluid flow to give a reliable regulation of the fluid
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`based by the temperature control of the wire.
`
`Seventh Embodiment <FIG. 13>
`
`FIG. 13 illustrates a fluid control valve in accordance with a
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`seventh embodimentof the present invention whichis similar to the fifth
`
`embodiment exceptthat the wire 60G is selected to have a characteristic
`
`of expanding its length when heated andthat the coil spring 50G is
`
`arranged to exert a force of pulling the valve body 30G towardsthe base
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`member 20G. Like parts are designated by like numerals with a suffix
`
`letter of “G”. The wire 60G stretches between the barrel 10G and the
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`valve body 30G against the bias of the spring 50G so as to move the
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`valve body 30G when heated to increase the valve opening, in an
`
`opposite sense to the above embodiments and modification.
`
`To this
`
`end, the wire 60G is formed at opposite ends with tension stoppers 63 at
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`positions respectively inwardly of the anchor member 12G and the catch
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`member 35G. The shape memory alloy wire 60G is selected to have a
`
`large diameter sufficient to achieve the above characteristics of
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`expanding when heated. The two wires 60G are connected in series by
`
` 10
`
`15
`
`20
`
`the like conductor 62G.
`
`
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`-18 -
`
`Whatis claimedis:
`
`1. A flow control valve assembly comprising:
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`a barrel having an axial bore within which an internal flow path
`
`for a fluid is formed to extend from an inlet to an outlet;
`
`a base memberdisposed at one axial end ofsaid barrel;
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`a valve body held in the other axial end of said barrel, said valve
`
`body being cooperative with said base memberto define therebetween a
`
`valve opening in the course of said internal flow path, said valve body
`
`being axially movable towards and away from said base memberto vary
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`said valve opening for regulating the flow of the fluid through said
`
`internal flow path;
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`a bias spring which urgessaid valve body for varying said valve
`
`opening in one direction ;
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`at least one shape memory alloy wire which connects said valve body to
`
`said barrel to exert, in response to thermal deformation, a force of
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`moving said valve body against said bias spring to vary the valve
`
`opening, said wire formed on its opposite ends with terminals by which
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`the wire is connectedto an electrical source for heating said wi