Surgery – Controlled release therapeutic device or system – Implanted dynamic device or system
Reexamination Certificate
2000-09-29
2002-05-21
Shaver, Kevin (Department: 3754)
Surgery
Controlled release therapeutic device or system
Implanted dynamic device or system
C604S009000, C251S065000, C251S177000, C251S233000, C251S234000, C137S524000, C137S530000, C137S531000
Reexamination Certificate
active
06391019
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a valve apparatus, more particularly, to a valve apparatus suitable for being used as a shunt valve embedded in the body for adjusting the pressure of the cerebrospinal fluid or the like and a valve system comprising the valve apparatus and a control device for controlling set pressure of the valve apparatus.
2. Description of the Prior Art
Japanese Patent Laid-Open No. 40063/1985 discloses a constitution in which there is provided in a flow path of the cerebrospinal fluid or the like for adjusting the pressure of the cerebrospinal fluid or the like, a shunt valve provided with a leaf-like spring one end portion of which is brought into contact with a ball serving as a valve element, other end portion of which is engaged with a cam face in a shape of a spiral staircase integrally formed with a rotor of a multiple poles step motor element and which changes press force of a ball by the spring by changing a flexing amount of the spring by moving the engaged end portion of the spring in an axial direction of the rotor in accordance with rotation of the cam face in correspondence with rotation of the rotor for treatment of hydrocephalus or the like.
However, in the case of the shunt valve apparatus, the thickness of the shunt valve apparatus is difficult to increase so considerably since the flexing direction of the spring is aligned to the thickness direction of the valve apparatus and therefore, when a comparatively wide range of pressure adjustment is made feasible by one kind of the shunt valve apparatus, it is necessary to comparatively increase a variation in press force exerted on the ball-like valve element even with a very small flexing amount of the spring and accordingly, even a very small dispersion in the flexing state of the spring is liable to amount to a large dispersion in the press force and it is not necessarily easy to adjust the press force to a predetermined value. Further, in order to change the flexing amount of the spring to adjust set pressure of the shunt valve apparatus, it is necessary to arrange a pressure adjusting or controlling device (shunt valve adjusting element) having a plurality of pieces of electromagnets along a circumferential direction such that the center of the device coincides accurately with the center of the multiple poles step motor element embedded in the body and therefore, the pressure adjustment is difficult to carry out easily.
Further, there is also known in, for example, Japanese Patent Laid-Open No. 170749/1996, a valve apparatus in which one end portion of a leaf spring bent substantially in a semicircular shape is fixed to a rotor having a permanent magnet, a peripheral face of a middle portion of the leaf spring extended to bend in the semicircular shape from the fixed end portion to a free end, is made to be able to be brought into contact with a valve element in a ball-like shape and press force of the ball by the spring is changed in accordance with a change in a position of bringing the spring and the ball into contact with each other in accordance with rotation of the rotor.
However, according to the valve apparatus, in order to be able to accurately adjust the press force exerted to the ball, a leaf spring in a specific bent state in substantially a semicircular shape is indispensable and it is not necessarily easy to realize a two-dimensional shape of such a spring with the least dispersion.
The invention has been carried out in view of the above-described points and it is an object thereof to provide a valve apparatus which is easy to set the press force exerted on a valve element with high accuracy and a valve system including the valve apparatus.
SUMMARY OF THE INVENTION
In order to achieve the object, according to an aspect of the invention, there is provided a valve apparatus comprising a long-sized elastic member a base end portion of which is fixed and a front end portion of which is brought into contact with a valve element, and a movable member movable actually linearly along a longitudinal direction of the elastic member between both end portions of the elastic member and having a fulcrum portion for flexing the elastic member between the both end portions of the elastic member.
According to the valve apparatus of the invention, there is provided the movable member movable actually linearly along the longitudinal direction of the elastic member between the fixed base end portion of the long-sized elastic member and the front end portion brought into contact with the valve element and having the fulcrum portion for flexing the elastic member between the both end portions of the elastic member and accordingly, the press force exerted on the valve element by the elastic member can be adjusted by adjusting the position of the fulcrum portion by adjusting the position of the movable member in the longitudinal direction of the elastic member to thereby change the spring constant of the elastic member between a position of supporting and pressing the elastic member by the fulcrum portion and a position of supporting (contacting) the elastic member by the valve element. Further, the elastic member is long-sized and the position of the movable member is moved in the longitudinal direction of the elastic member in order to change the flexing state of the elastic member and accordingly, an amount of moving the movable member can be increased even for slightly changing the flexing state of the elastic member. Therefore, the flexing state is easy to adjust accurately. Further, the elastic member is fixed at the base end portion and is brought into contact with the valve element at the front end portion and supported by the valve element to thereby bring about a doubly supported state and accordingly, not only the elastic member can be held stably but also a flexing deformation is added at the middle portion in the longitudinal direction of the elastic member in the doubly supported state by the fulcrum portion and therefore, there is less concern of concentrating stress at one portion of the elastic member, the flexing state of the elastic member is easy to control accurately and there is less concern of variation or deterioration in the flexing characteristic of the elastic member even when the elastic member is used for a long period of time.
The elastic member is typically constituted by a leaf spring. However, when desired, the elastic member may be a structure of an elastic member material capable of setting the characteristic of the flexing deformation in a desired manner.
When the elastic member comprises a leaf spring, at least one of a thickness, a width, an inclination and a contour line of a face pressed by the fulcrum portion of the spring may be changed in accordance with a position of the spring in the longitudinal direction such that the press force of the valve element by the spring is varied in a desired pattern in accordance with moving the fulcrum portion in the longitudinal direction of the spring. In this case, the way of varying the press force may be constituted such that when the movable member is moved in a direction of approaching the valve element along the longitudinal direction of the spring, the press force of the valve element by the spring is increased actually linearly or increased sublinearly. Further, a degree of the increase (for example, inclination in the linear case) may be made comparatively large or small. With regard to the width of the spring, the width may be varied such that, for example, the more proximate to the front end portion, the larger the width, or conversely, the smaller the width, the width is varied along the longitudinal direction by other mode (for example, such that the more proximate to the front end portion, the larger the width in a range from a middle predetermined position to the front end portion or the width is large at a central portion in the longitudinal direction and is small at both end sides or the width is small at the central portion in the longitudinal direc
Adams & Wilks
Bonderer David A
Seiko Instruments Inc.
Shaver Kevin
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