Lever displacement enlarging mechanism

The invention provides a lever displacement enlarging mechanism which is applicable for a positioning apparatus of an optical stage, is provided with bisymmetrical levers enlarging and transmitting a displacing force of an actuator element, and in which the distance between the leading end sides of boundary grooves and outer edges of coupling posts is smaller than that between the trailing end sides thereof and the outer edges and action point hinges are located closer to the axis of symmetry so that the fulcrum hinges and the force point hinges are closer to the outer edges of the coupling posts.

TECHNICAL FIELD 
The present invention relates to a lever displacement enlarging mechanism 
applicable in an optical stage positioning apparatus, a micro-flow rate 
control valve (mass flow controller) and so on. More particularly, the 
present invention relates to a lever displacement enlarging mechanism 
which is applicable to an apparatus in which it is difficult to provide 
enough space for housing a displacement enlarging mechanism from design 
considerations, and is still required to give a prescribed enlarging ratio 
of displacement, or of which straight forwarding property or 
straightforward displacement of the output displacement section is 
required. 
BACKGROUND ART 
In a conventional micro-flow rate control valve, it has been a common 
practice to generate a micron-order displacement by piling up a number of 
piezo-electric elements. These many piled-up piezo-electric elements are 
housed in a small space, for example, of 20 mm.times.50 mm.times.50 mm. 
However, because the piezo-electric element is expensive in cost, this 
conventional practice poses economic problems. 
It is therefore conceivable to use a lever displacement enlarging mechanism 
based on a single piezo-electric element (see Japanese Provisional Patent 
Publication No. H4-218,981). 
Conventional cases have however the following problems: 
(1) In the design of this displacement enlarging mechanism, components must 
be housed in a limited space as described above. However, a size capable 
of being housed in this limited space makes it impossible to achieve a 
desired ratio of enlargement particularly because of a limited lever 
ratio. Increasing a size of a lever is naturally conceivable, but an 
increased lever ratio leads to a larger shape, resulting in a larger-sized 
apparatus as a whole, and also in a lower transmitting efficiency of the 
amount of displacement and of the generated force to the output end. 
(2) As it is the usual practice to apply a preliminary pressure by directly 
pressing the piezo-electric elements by means of bolts, the piezo-electric 
elements may sometimes be broken. 
(3) Since the lever of the lever displacement enlarging mechanism is not 
provided bisymmetrically, a rotating component is added to a displacement. 
So, the enlarged amount of displacement of the piezo-electric elements 
cannot be transmitted as it is. 
(4) Because the force point, the fulcrum and the action point are not 
arranged on a straight line, the direction of displacement would contain a 
rotating component, this resulting in displacement of the output 
displacement section of the mechanism while curving. It is therefore 
difficult to keep straight forwarding property, and furthermore 
transmission efficiency of the amount of displacement and the generating 
force decreases. 
In view of the circumstances described above, the present invention has an 
object to provide a large displacement enlarging ratio while achieving 
downsizing of the apparatus. 
Another object of the invention is to realize prevention of breakage of an 
actuator element, and easy adjustment of the preliminary pressure. 
A further object of the invention is to ensure straight forwarding property 
of the output displacement section. 
SUMMARY OF THE INVENTION 
The lever displacement enlarging mechanism of the invention comprises a 
fixed portion and a movable portion holding both ends of an actuator 
element in between in a direction of displacement; bisymmetrical coupling 
posts connectively disposed on both sides of the fixed portion, and having 
respectively a leading end part thereof facing the movable portion via a 
boundary groove; bisymmetrical fulcrum hinges respectively connecting a 
leading end of the respective coupling posts and a lever; bisymmetrical 
force point hinges respectively connecting a leading end of the movable 
portion and the lever; and bisymmetrical action point hinges respectively 
connecting the lever and an output displacement section; wherein the 
distance between a leading end side of the boundary groove and an outer 
edge of the coupling post is made smaller than the distance between the 
trailing end side thereof and the outer edge so that the fulcrum hinge and 
the force point hinge are closer to the outer edge of the coupling post; 
and the action point hinge is located at a position closer to an axis of 
symmetry. It is thus possible to achieve downsizing of the apparatus and 
improve the displacement enlarging ratio. 
The lever displacement enlarging mechanism of the invention comprises a 
fixed portion and a movable portion holding both ends of an actuator 
element in between in a direction of displacement; bisymmetrical coupling 
posts connectively disposed on both ends of the fixed portion, and having 
respectively a leading end part thereof facing the movable portion via a 
boundary groove; bisymmetrical fulcrum hinges connecting respectively a 
leading end of the coupling post and a lever; bisymmetrical force point 
hinges connecting respectively a leading end of the movable portion and 
the lever; and bisymmetrical action point hinges connecting respectively 
the lever and an output displacement section; wherein the distance between 
a leading end side of the boundary groove and an outer edge of the 
coupling post is made smaller than the distance between a trailing end 
side thereof and the outer edge so that the fulcrum hinge and the force 
point hinge are closer to the outer edge of the coupling post; and the 
action point is located at a position closer to an axis of symmetry, and 
wherein a wedge for adjusting a preliminary pressure is provided between 
the fixed portion and the actuator element. It is therefore possible to 
downsize the apparatus, improve the displacement enlarging ratio, and 
prevent breakage of the actuator element. 
The lever displacement enlarging mechanism of the invention comprises an 
upper fixed portion and a push plate holding both ends of an actuator 
element in between in a direction of displacement; bisymmetrical first 
force point hinges connecting the push plate and first levers; 
bisymmetrical first fulcrum hinges connecting the first levers and a lower 
fixed portion; bisymmetrical coupling posts connectively disposed on both 
sides of the first levers via first action point hinges, and having 
leading ends facing the upper fixed portion via boundary grooves; 
bisymmetrical second force point hinges connecting leading ends of the 
coupling posts and second levers; bisymmetrical second fulcrum hinges 
connecting leading ends of the upper fixed portion and the second levers; 
and bisymmetrical second action point hinges connecting the second levers 
and an output displacement section; wherein action points, force points 
and fulcrums of the first levers are positioned on a straight line; and 
the distance between leading end sides of the boundary grooves and outer 
edges of the coupling posts is made smaller than the distance between 
trailing end sides thereof and the outer edges so that the second fulcrum 
hinges and the second force point hinges are closer to the outer edges of 
the coupling posts, and the second action point hinges are located at 
positions closer to an axis of symmetry; and wherein a wedge for adjusting 
a preliminary pressure is provided between the fixed portion and the 
actuator element. It is thus possible to downsize the apparatus, improve 
the displacement enlarging ratio, and prevent breakage of the actuator 
element. 
The lever displacement enlarging mechanism of the invention comprises a 
fixed portion and a movable portion holding both ends of an actuator 
element in between in a direction of displacement; bisymmetrical coupling 
posts connectively disposed on both sides of the fixed portion, and having 
respectively a leading end part thereof facing the movable portion via a 
boundary groove; bisymmetrical fulcrum hinges connecting respectively a 
leading end of the coupling post and a lever; bisymmetrical force point 
hinges connecting respectively a leading end of the movable portion and 
the lever; and bisymmetrical action point hinges connecting respectively 
the lever and an output displacement section. There is provided straight 
forward correcting means for imparting a displacement direction correcting 
force to the hinges of the levers. It is therefore possible to ensure the 
straight forwarding property of the output displacement section.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
An embodiment of the invention will now be described with reference to 
FIGS. 1 and 2. This embodiment covers a two-stage lever displacement 
enlarging mechanism provided with a first and a second lever displacement 
mechanisms A and B. 
A cut groove H is formed through electric discharge fabrication, laser 
fabrication, etc. of a rectangular plate such as a stainless steel plate 
P, and there are formed a housing portion 2, an upper fixed portion 5, 
bisymmetrical first levers 8a and 8b, a lower fixed portion 10, 
bisymmetrical coupling posts 12a and 12b, bisymmetrical second levers 14a 
and 14b, and an output displacement section 17. 
In the housing portion 2, an actuator element 1 is arranged, and a lower 
end 1a thereof is pressed into contact with a push plate 6 via a lower 
protecting plate 3b. The actuator element 1 is an upright actuator element 
displacing in the direction of an axis of symmetry 1C of the plate P, such 
as a piezo-electric, electrostrictive, or magnetostrictive element. 
A push plate 6 is connected to the bisymmetrical first levers 8a and 8b via 
force point hinges 7a and 7b of the first lever displacement enlarging 
mechanism A arranged bisymmetrically. 
The first levers 8a and 8b are connected to lower ends of the 
bisymmetrically arranged coupling posts 12a and 12b via bisymmetrical 
action point hinges 11a and 11b. These action point hinges 11a and 11b are 
located at positions closer to outer edges 12c and 12d of the coupling 
posts 12a and 12b. 
The first levers 8a and 8b are connected to the lower fixed portion 10 via 
bisymmetrical fulcrum hinges 9a and 9b. These fulcrum hinges 9a and 9b are 
located closer to an axis of symmetry 1C, and connected sideways to the 
lower fixed portion 10, effectuating a small distance between fulcrums and 
force points. As a result, it is possible to increase the lever ratio of 
the first levers 8a and 8b and downsize the apparatus as a whole. Because 
the fulcrums, the force points and the action points of the first levers 
8a and 8b are on a straight line L1, the direction of displacement is 
along the direction of the axis of symmetry 1C, producing almost no 
rotation component. 
A top end 1b of the aforesaid actuator element 1 is pressure-connected to 
the upper fixed portion 5 via an upper protecting plate 3a and a wedge 
plate 4. The wedge plate 4 imparts a preliminary pressure to a 
piezo-electric element and prevents a damage to the piezo-electric element 
upon imparting the preliminary pressure. An appropriate preliminary 
pressure is imparted by adjusting the thickness and the amount of pressing 
of the wedge plate 4. 
The upper fixed portion 5 is formed into an inverted trapezoid, and has 
bisymmetrical upper fulcrum hinges 15a and 15b at top corners thereof. The 
upper fulcrum hinges 15a and 15b are connected to second levers 14a and 
14b of a second lever displacement enlarging mechanism B, arranged 
bisymmetrically. The second levers 14a and 14b are bisymmetrically 
arranged and are connected to a central projection 17c of the output 
displacement section 17 via bisymmetrical action point hinges 16a and 16b. 
The output displacement section 17 is connected to a valve rod or the like 
of a micro-fow rate control valve not shown. 
The second levers 14a and 14b are connected to top ends of the coupling 
posts 12a and 12b via second force point hinges 13a and 13b. Top end parts 
12e and 12f of the coupling posts 12a and 12b face the upper fixed portion 
5 via boundary grooves 21a and 21b. The top end parts 12e and 12f are 
tapering to the ends, and the boundary grooves 21a and 21b incline 
diagonally upward to outside. 
This geometry of the boundary grooves 21a and 21b gives the following 
advantages: 
(1) The distance between the second force point hinges 13a and 13b, on the 
one hand, and the second fulcrum hinges 15a and 15b, on the other hand, 
can be reduced, thus achieving increasing the lever ratio of the second 
levers 14a and 14b. 
(2) Elongation caused by deformation of the coupling posts 21a and 12b can 
be reduced. 
(3) The second force point hinges 13a and 13b and the second fulcrum hinges 
15a and 15b are positioned closer to the outer edges 12c and 12d of the 
coupling posts 12a and 12b, and largely apart from the action point hinges 
16a and 16b in the proximity of the axis of symmetry 1C, so that the lever 
ratio can be improved. 
Because the lower fixed portion 10 is separated from the upper fixed 
portion 5, coupling plates 18a and 18b are arranged on the surface side 
and the back side of the foregoing plate P, as shown in FIG. 2, and a 
fixing bolt and nut 20 is inserted into an upper fixing hole 5a and a 
lower fixing hole 10a to tighten for integration of these components. 
To avoid contact with a movable component such as a lever to be displaced 
by the actuator element 1, the coupling plates 18a and 18b are tightened 
by holding spacers 19a and 19b identical with the contours of the upper 
fixed portion 5 and the lower fixed portion 10 in between. 
Now, operations of this embodiment of the invention will be described 
below. When applying a voltage to the actuator element such as a 
piezo-electric element 1, the piezo-electric element 1 elongates in the 
direction of the axis of symmetry 1C in response to the applied voltage, 
and moves the push plate 6 in the arrow A2 direction against the 
preliminary pressure. 
When the push plate 6 moves in the arrow A2 direction, a force acts in the 
arrow A2 direction on the first levers 8a and 8b via the force point 
hinges 7a and 7b of the first lever displacement enlarging mechanism A. As 
a result, the levers 8a and 8b cause the coupling posts 12a and 12b to 
move in the arrow A2 direction via the action point hinges 11a and 11b. 
Since the second force point hinges 13a and 13b of the second levers 14a 
and 14b are pulled in the arrow A2 direction by the displacement of the 
coupling posts 12a and 12b, the output displacement section 17 moves in 
the arrow A1 direction via the second action point hinges 16a and 16b. 
The amount of displacement of the piezo-electric element 1 is largely 
enlarged by the law of lever and transmitted to the output displacement 
section 17. Because the lever displacement enlarging mechanisms A and B 
are bisymmetrically arranged, the displacement is free from a rotating 
component, having only a component in the direction of the axis of 
symmetry 1C. 
The second action point hinges 16a and 16b and the second force point 
hinges 13a and 13b of the second lever displacement enlarging mechanism B 
move in accordance with the law of lever, the former and the latter moving 
in a counter direction with each other. It is therefore available to 
largely enlarge the amount of displacement. 
When the applied voltage is brought to null, the apparatus is reset to zero 
by the restoring force of the fulcrum, force point and action point hinges 
of the first levers 8a and 8b and the second levers 14a and 14b. Opening 
of the valve is adjusted by driving the output displacement section 17 
while repeating a change in voltage. 
As is evident from the above description, the lever displacement enlarging 
mechanism of the invention provides the following remarkable advantages: 
(1) Because the lever displacement enlarging mechanisms are bisymmetrically 
arranged, the displacement is free from a rotation component, consisting 
only of the component in the direction of the axis of symmetry, so that 
the enlarged amount of displacement of the piezo-electric element can be 
transmitted correctly. 
(2) The distance between the leading end sides of the boundary grooves and 
the outer edges of the coupling posts is made smaller than the distance 
between the trailing end sides thereof and the outer edges so that the 
fulcrum hinges and the force point hinges are closer to the outer edges of 
the coupling posts, and the action point hinges are arranged closer to the 
axis of symmetry. A lever ratio larger than that available in the 
conventional art can therefore be obtained. A compact apparatus giving a 
large amount of enlarged displacement is thus available. 
(3) By using the coupling posts, the fulcrums, the force points and the 
action points can be arranged on a straight line. A rotating component is 
consequently eliminated in the direction of displacement, and displacement 
component becomes a straight forwarding displacement. 
(4) The wedge provided permits imparting a preliminary pressure to the 
actuator element and preventing breakage. Because of the nature of a 
wedge, it is possible to easily impart a desired preliminary pressure to 
that element by adjusting the thickness and the extent of hammering. 
A second embodiment of the invention will now be described below with 
reference to FIG. 3. This embodiment covers a three-stage lever 
displacement enlarging mechanism provided with a first, a second and a 
third lever displacement enlarging mechanisms C, D and E. 
A plate such as a stainless steel plate P is provided with a cut groove H 
formed through discharge fabrication, laser fabrication, etc., and there 
are formed a housing portion 22, a fixed portion 25, bisymmetrical first 
levers 28a and 28b, coupling posts 32a and 32b, second levers 34a and 34b, 
third levers 40a and 40b, tops 50a and 50b, a block 60, coupling tops 70a 
and 70b, and an output displacement section 37. 
An actuator element 21 is arranged in the housing portion 22, and a lower 
end 21c thereof is pressure-connected to a push plate 26 via a lower 
protecting plate 23b. The actuator element 21 is an upright actuator 
element displacing in the direction of the axis of symmetry 2C of the 
plate P, such as a piezo-electric, electrostrictive or magnetostrictive 
element. 
The push plate 26 is connected to the bisymmetrical first levers 28a and 
28b via first force point hinges 27a and 27b of a first lever displacement 
enlarging mechanism C. 
The first levers 28a and 28b are connected to lower ends of coupling posts 
32a and 32b arranged bisymmetrically via bisymmetrical action point hinges 
31a and 31b. 
The first levers 28a and 28b are connected to side posts 25n and 25m of the 
fixed portion via bisymmetrical fulcrum hinges 29a and 29b. As the 
fulcrums, the force points and the action points of the first levers 28a 
and 28b are located on a straight line L2, the direction of displacement 
is in the direction of the axis of symmetry 2C, and there is produced 
almost no rotating component. 
The top end 21d of the actuator element 21 is pressure-connected to the 
fixed portion 25 via an upper protecting plate 23a and a wedge plate 24. 
The wedge plate 24 imparts a preliminary pressure to the piezo-electric 
element, and prevents a damage to the piezo-electric element. An 
appropriate preliminary pressure can be imparted to the piezo-electric 
element by adjusting the thickness and the amount of pressing the wedge 
plate 24. 
The fixed plate 25 is fixed by a fixing screw 25a, and bisymmetrical second 
fulcrum hinges 39a and 39b are provided at top corners thereof. The second 
fulcrum hinges 39a and 39b are connected to second levers 34a and 34b of 
the second lever displacement enlarging mechanism D arranged 
bisymmetrically. 
The second levers 34a and 34b are bisymmetrically arranged, and connected 
to bisymmetrical tops 50a and 50b via bisymmetrical second action point 
hinges 36a and 36b. The tops 50a and 50b are formed into trapezoids. 
The second levers 34a and 34b are connected to top ends of the coupling 
posts 32a and 32b via second force point hinges 33a and 33b. The coupling 
posts 32a and 32b face side posts 25n and 25m of the fixed portion 25 via 
boundary grooves 42a and 42b. The coupling posts 32a and 32b are 
convergent toward the tips, i.e., tapered. As a result, the boundary 
grooves 42a and 42b between the fixed portion 25 and the coupling posts 
32a and 32b diagonally incline upward to outside. 
When the boundary grooves 42a and 42b are formed as described above, the 
following advantages are available: 
(1) The distance between the second force point hinges 33a and 33b, on the 
one hand, on the second fulcrum hinges 39a and 39b, on the other hand, can 
be reduced, thus achieving increasing the lever ratio of the second levers 
34a and 34b. 
(2) Elongation caused by deformation of the coupling posts 32a and 32b can 
be reduced. 
(3) The second force point hinges 33a and 33b and the second fulcrum hinges 
39a and 39b are positioned closer to outer edges 32c and 32d of the 
coupling posts 32a and 32b, and largely apart from the action point hinges 
36a and 36b in the proximity of the axis of symmetry C2, so that the lever 
ratio can be improved. 
The bisymmetrical second levers 34a and 34b are connected to the third 
levers 40a and 40b via the bisymmetrical tops 50a and 50b. The tops 50a 
and 50b are formed into trapezoid, have ends on one side connected to the 
second levers 34a and 34b via the bisymmetrical second action point hinges 
36a and 36b, and the other ends connected to the third levers 40a and 40b 
of the third lever displacement enlarging mechanism E via bisymmetrical 
third force point hinges 57a and 57b. 
In the third lever displacement enlarging mechanism E, the force points and 
the fulcrums are closer to each other and located closer to the axis of 
symmetry 2C, and the action points are located on the side of outer edges 
40c and 40d of the third levers, thus achieving increasing the lever 
ratio. The third levers 40a and 40b are connected to a block 60 via 
bisymmetrical third fulcrum hinges 49a and 49b connected to the fixed 
portion 25 via a fulcrum 61. 
The third levers 40a and 40b are connected to ends on one side of 
bisymmetrical coupling tops 70a and 70b via bisymmetrical third action 
point hinges 46a and 46b. The other ends of the tops 70a and 70b are 
connected to an output displacement section 37 which is in turn connected 
to a valve rod or the like of the micro-flow rate control valve not shown. 
Now, operations of this embodiment of the invention will be described 
below. When applying a voltage to the actuator element such as a 
piezo-electric element 21, the piezo-electric element 21 elongates in the 
direction of the axis of symmetry 2C in response to the applied voltage, 
and moves the push plate 26 in the arrow A2 direction against the 
preliminary pressure. 
When the push plate 26 moves in the arrow A2 direction, a force acts in the 
arrow A2 direction on the first levers 28a and 28b via the force point 
hinges 27a and 27b of the first lever displacement enlarging mechanism C. 
As a result, the levers 28a and 28b cause the coupling posts 32a and 32b 
to move in the arrow 1 direction via the action point hinges 31a and 31b. 
Since the second force point hinges 33a and 33b of the second levers 34a 
and 34b are pushed in the arrow A1 direction by the displacement of the 
coupling posts 32a and 32b, the action point hinges 36a and 36b of the 
second levers 34a and 34b move in the arrow A2 direction. As a result, the 
tops 50a and 50b are caused to move in the arrow A2 direction. At this 
point, the force points and the fulcrums of the second lever displacement 
enlarging mechanism D are close to each other and located on the side of 
the outer edges 32c and 32d of the coupling posts 32a and 32b, and the 
action points are located closer to the axis of symmetry 2C. All these 
points are bisymmetrical, resulting in a larger lever ratio and also a 
large amount of displacement in the direction of the axis of symmetry 2C, 
i.e., the arrow A1 direction. 
Presence of the tops 50a and 50b leads to a smaller resistance of the 
hinges, and hence to a higher transmitting efficiency. 
Since the third force point hinges 57a and 57b of the third levers 40a and 
40b are pulled in the arrow A2 direction by the displacement of the tops 
50a and 50b in the arrow A2 direction, the third action point hinges 46a 
and 46b of the third lever displacement enlarging mechanism E cause the 
output displacement section 37 to move in the arrow A1 direction via the 
coupling tops 70a and 70b. The coupling tops 70a and 70b serve to reduce 
resistance of the hinges and improve the transmitting efficiency. 
The amount of displacement of the piezo-electric element 21 is largely 
enlarged by the law of lever and transmitted to the output displacement 
section 37. Because the lever displacement enlarging mechanisms C, D and E 
are bisymmetrically arranged respectively, the displacement is free from a 
rotating component, having only a component in the direction of the axis 
of symmetry 2C. 
When the applied voltage is brought to null, the apparatus is reset to zero 
by the restoring force of the fulcrums, the force points and the action 
points of the first levers 28a and 28b, the second levers 34a and 34b, and 
the third levers 40a and 40b. Opening of the valve is adjusted by driving 
the output displacement section 37 while repeating a change in voltage. 
A third embodiment of the invention will now be described below with 
reference to FIG. 4. This embodiment relates to a one-stage lever 
displacement enlarging mechanism having a lever displacement enlarging 
mechanism F. 
A plate such as a stainless steel plate P is provided with a cut groove H 
formed through discharge fabrication, laser fabrication, or the like, and 
there are formed a housing portion 102, a fixed portion 105 fixed with a 
screw N, bisymmetrical levers 108a and 108b, a movable portion 110, 
bisymmetrical coupling posts 112a and 112b, and an output displacement 
section 117. 
An actuator element 101 is arranged in the housing portion 102, and a lower 
end 101a thereof is pressure-connected to the fixed portion 105 via a 
lower protecting plate 103b, and a wedge plate 104. 
The actuator element 101 is an upright actuator element displacing in the 
direction of the axis of symmetry 3C of the plate P, such as a 
piezo-electric, electrostrictive or magnetostrictive element. 
The wedge plate 104 imparts a preliminary pressure to the piezo-electric 
element and prevents a damage to the piezo-electric element. An 
appropriate preliminary pressure can be imparted to the piezo-electric 
element by adjusting the thickness and the amount of pressing of the wedge 
plate 104. 
A top end 101b of the actuator element 101 is pressure-connected to the 
movable portion 110 via an upper protecting plate 103a. 
The movable portion 110 is formed into an inverted trapezoid, and has 
bisymmetrical force point hinges 113a and 113b formed at top corners 
thereof. The force point hinges 113a and 113b are connected to 
bisymmetrically arranged levers 108a and 108b of the lever displacement 
enlarging mechanism F. 
The levers 108a and 108b are bisymmetrically provided, and connected to the 
output displacement section 117 via bisymmetrical action point hinges 106a 
and 106b. The output displacement section 117 is connected to a valve rod 
of a micro-flow rate control valve not shown. 
The levers 108a and 108b are connected to top ends of the coupling posts 
112a via fulcrum hinges 115a and 115b. Leading end parts 112e and 112f of 
the coupling posts 112a and 112b face the movable portion 110 via boundary 
grooves 121a and 121b. The leading end parts 112e and 112f taper to the 
ends, and the boundary grooves 121a and 121b diagonally incline upward to 
outside. 
When forming the boundary grooves 121a and 121b as described above, the 
following advantages are available: 
(1) The distance between the force point hinges 113a and 113b, on the one 
hand, and the fulcrum hinges 115a and 115b, on the other hand, can be 
reduced, thus achieving increasing the lever ratio of the levers 108a and 
108b. 
(2) Elongation caused by the deformation of the coupling posts 112a and 
112b can be reduced. 
(3) The force point hinges 113a and 113b and the fulcrum hinges 115a and 
115b can be positined closer to outer edges 112c and 112d of the coupling 
posts 112a and 112b, and largely apart from the action point hinges 106a 
and 106b in the proximity of the axis of symmetry 3C, so that the lever 
ratio can be improved. 
Now, operations of this embodiment of the invention will be described 
below. When applying a voltage to the actuator element such as a 
piezo-electric element 101, the piezo-electric element 101 elongates in 
the direction of the axis of symmetry 3C in response to the applied 
voltage, and moves the movable portion 110 in the arrow A1 direction 
against the preliminary pressure. 
When the movable portion 110 moves in the arrow A1 direction, a force acts 
in the arrow A1 direction on the action point hinges 106a and 106b of the 
levers 108a and 108b via the force point hinges 113a and 113b of the lever 
displacement enlarging mechanism F. As a result, the output displacement 
section 117 moves in the arrow A1 direction. At this point, the fulcrum 
hinges 115a and 115b and the force point hinges 113a and 113b are closer 
to each other and are positioned on the side of the outer edges 112c and 
112d of the coupling posts 112a and 112b. The action point hinges 106a and 
106b are located on the side of the axis of symmetry 3C, and all the 
hinges are bisymmetrical respectively. This results in a larger lever 
ratio, and also results in the direction of displacement in the arrow A1 
direction, parallel with the axis of symmetry 3C. 
The amount of displacement of the piezo-electric element 101 is largely 
enlarged by the law of lever and transmitted to the output displacement 
section 117. Because the lever displacement enlarging mechanism F is 
bisymmetrically arranged, the displacement is free from a rotating 
component, having only a component in the direction of the axis of 
symmetry 3C. 
When the applied voltage is brought to null, the apparatus is reset to zero 
by the restoring force of the fulcrum, force point and action point hinges 
of the levers 108a and 108b. Opening of the valve is adjusted by driving 
the output displacement section 117 while repeating a change in voltage. 
Application of the invention is not limited to the embodiments presented 
above, but covers various others, for example, the fourth embodiment shown 
in FIG. 5 and the fifth embodiment shown in FIG. 6, wherein a boundary 
groove is configurated otherwise than the inclined boundary groove. Both 
the FIGS. 5 and 6 correspond to FIG. 1 illustrating the first embodiment: 
FIG. 5 illustrates a boundary groove 200 formed into an L shape, and FIG. 
6, a boundary groove 300 formed into steps. In any of these cases, leading 
end parts 202 and 302 of coupling posts 201 and 301 are thinner than 
trailing end parts 205 and 305 thereof, and force point hinges 206 and 306 
and fulcrum hinge 15a are located on the side of outer edges 201c and 301c 
of the coupling posts 201 and 301. 
By arranging fulcrums and force points close to each other and on the side 
of outer edges 201c and 301c of the coupling posts, and action points on 
the side of the axis of symmetry 4C, the distance between the fulcrums and 
the force points, on the other hand, and the action points, on the other 
hand, can be increased, and the lever ratio can be improved even without 
increasing the width of the apparatus. As a result, a large amount of 
displacement is available with a compact apparatus. 
Now, a sixth embodiment of the invention will be described below with 
reference to FIG. 7. This embodiment has a configuration in which a 
straight forwarding means S is added to the three-stage lever displacement 
enlarging mechanism of the second embodiment (FIG. 3). A plate such as a 
stainless steel plate P is provided with a cut groove H formed through 
discharge fabrication, laser fabrication, or the like, and there are 
formed a housing portion 22, a fixed portion 25, bisymmetrical first 
levers 28a and 28b, coupling posts 32a and 32b, second levers 34a and 34b, 
third levers 40a and 40b, tops 50a and 50b, a block 60, coupling tops 70a 
and 70b, and an output displacement section 37. 
An actuator element 21 is arranged in the housing portion 22, and a lower 
end 21c thereof is pressure-connected to a push plate 26 via a lower 
protecting plate 23b. The actuator element 21 is an upright actuator 
element displacing in the direction of the axis of symmetry 2C of the 
plate P, such as a piezo-electric, electrostrictive or magnetostrictive 
element. 
The push plate 26 is connected to the bisymmetrical first levers 28a and 
28b via bisymmetrical first force point hinges 27a and 27b of a first 
lever displacement enlarging mechanism C. 
The first levers 28a and 28b are connected to lower ends of the coupling 
posts 32a and 32b arranged bisymmetrically via bisymmetrical action point 
hinges 31a and 31b. 
The first levers 28a and 28b are connected to side posts 25n and 25m of the 
fixed portion via bisymmetrical fulcrum hinges 29a and 29b. As the 
fulcrums, the force points and the action points of the first levers 28a 
and 28b are located on a straight line L2, the direction of displacement 
is in the direction of the axis of symmetry 2C, and there is produced 
almost no rotating component. 
A hemisphere 21B is fixed to a top end 21d of the actuator element 21, and 
the hemisphere 21B is pressure-connected to the fixed portion 25 via an 
upper protecting plate 23a having a receiving recess 23P with a V-shape 
cross-section, a wedge plate 24, and a wedge receiving plate 24A. 
The wedge plate 24 imparts a preliminary pressure to the piezo-electric 
element and prevents a damage to the piezo-electric element. An 
appropriate preliminary pressure can be imparted to the piezo-electric 
element by adjusting the thickness and the amount of pressing of the wedge 
plate 24. The actuator element 21 is pressure-connected to the fixed 
portion 25 via a ball joint comprising the hemisphere 21B and the upper 
protecting plate 23a having the receiving recess 23P with a V-shaped 
cross-section. Therefore, even when a force is applied to the 
piezo-electric element in a direction different from the direction of 
displacement of the piezo-electric element, the applied force is absorbed 
under the effect of the ball joint. 
An unreasonably large force therefore does not act on the piezo-electric 
element, thus effectuating avoidance of a breakage of the piezo-electric 
element. 
The fixed portion 25 is fixed by a fixing screw 25a, and bisymmetrical 
second fulcrum hinges 39a and 39b are provided at top corners. The second 
fulcrum hinges 39a and 39b are connected to the second levers 34a and 34b 
of a bisymmetrical arranged second lever displacement enlarging mechanism 
D. 
The second levers 34a and 34b are bisymmetrically arranged and connected to 
the bisymmetrical tops 50a and 50b via second action point hinges 36a and 
36b. The tops 50a and 50b are formed into trapezoids. 
The second levers 34a and 34b are connected to top ends of the coupling 
posts 32a and 32b via second force point hinges 33a and 33b. The coupling 
posts 32a and 32b face the side posts 25n and 25m of the fixed portion 25 
via boundary grooves 42a and 42b. The coupling posts 32a and 32b are 
divergent toward the leading ends thereof, i.e., spreading out toward the 
ends. As a result, the boundary grooves 42a and 42b between the fixed 
portion 25 and the coupling posts 32a and 32b diagonally incline upward to 
inside. 
The bisymmetrical second levers 34a and 34b are connected to the third 
levers 40a and 40b via the bisymmetrical tops 50a and 50b. The tops 50a 
and 50b are formed into trapezoids. One-side ends thereof are connected to 
the second levers 34a and 34b via the bisymmetrical action point hinges 
36a and 36b, and the other ends, to the third levers 40a and 40b of a 
third lever displacement enlarging mechanism E via the bisymmetrical third 
force point hinges 57a and 57b. 
In this third lever displacement enlarging mechanism E, the force points 
and the fulcrums are close to each other and are located on the side of 
the axis of symmetry 2C, and the action points are located on the side of 
outer edges 40c and 40d of the third levers, thus achieving improving 
lever ratio. The third levers 40a and 40b are connected to a block 60 via 
third fulcrum hinges 49a and 49b. The block 60 is connected to the fixed 
portion 25 via a post 61. 
The third levers 40a and 40b are connected to one-side ends of 
bisymmetrical tops 70a and 70b via bisymmetrical third point hinges 46a 
and 46b. The other ends of the tops 70a and 70b are connected to the 
output displacement section 37 via the straight forwarding means S. The 
center axis of the output displacement section 37 is located on the axis 
of symmetry 2C, and the output displacement section 37 is connected to a 
valve rod or the like of a micro-flow rate control valve not shown. 
The straight forwarding means S gives a displacement direction correcting 
force to the hinges of the levers. It adjusts the displacement force of 
the actuator element 21 enlarged via the lever displacement enlarging 
mechanisms C, D and E to a displacing force in a direction in parallel 
with the axis of symmetry 2C, and causes the output displacement section 
37 to go straight ahead, i.e., to move while always positioning the center 
axis of the output displacement section 37 on the axis of symmetry 2C. 
For example, a ball plunger 300 is used as the straight forwarding means S. 
The straight forwarding means S comprises a ball 301 pressure-connected to 
a side wall 60W of the block 60 and a screw 303 having a built-in spring 
302 for pressing the ball 301. 
Now, operations of this embodiment will be described below. 
First, the straight forwarding means S is adjusted. A mirror not shown is 
placed at the center portion M of the output displacement section 37, and 
while irradiating a light beam in a direction perpendicular to the axis of 
symmetry 2C onto the mirror, the mirror angle is adjusted so that the 
reflected beam is in parallel with the axis of symmetry 2C. 
Thereafter, the actuator element 21 is made to drive while continuing 
irradiation, adjusting of right and left pressing force is done by 
rotating the right and left ball plungers so as to always keep the 
reflected beam to be in pararell with the axis of symmetry, to effectuate 
applying a displacing direction correcting force of the levers of the 
lever displacement enlarging mechanisms C, D and E. 
When a voltage is applied to the actuator element such as a piezo-electric 
element 21, the piezoelectric element 21 elongates in the direction of the 
axis of symmetry 2C in response to the applied voltage against the 
preliminary pressure, thus causing the push plate 26 to move in the A2 
direction. 
When the push plate 26 moves in the arrow A2 direction, a force in the 
arrow A2 direction acts on the first levers 28a and 28b via the force 
point hinges 27a and 27b of the first lever displacement enlarging 
mechanism C. As a result, the levers 28a and 28b cause the coupling posts 
32a and 32b to move in the arrow A1 direction via the action point hinges 
31a and 31b. 
Since movement of the coupling posts 32a and 32b pushes the second force 
point hinges 33a and 33b of the second levers 34a and 34b in the arrow A1 
direction, the action point hinges 36a and 36b of the second levers 34a 
and 34b move in the arrow A2 direction. As a result, the tops 50a and 50b 
move in the arrow A2 direction. 
At this point, the force points and the fulcrums of the second lever 
displacement enlarging mechanism D are close to each other and are located 
closer to the side of the outer edges 32c and 32d of the coupling posts 
32a and 32b. The action points are located closer to the axis of symmetry 
2C. Because all these points are bisymmetrical, there is available a large 
lever ratio, and a large amount of displacement can be obtained in the 
direction of the axis of symmetry 2C, i.e., in the arrow A2 direction. 
Presence of the tops 50a and 50b reduces the resistance of the hinges, 
enabling higher transmitting efficiency. 
Because the displacement of the tops 50a and 50b in the arrow A2 direction 
pulls the third force point hinges 57a and 57b of the third levers 40a and 
40b in the arrow A2 direction, the third action point hinges 46a and 46b 
of the third lever displacement enlarging mechanism E cause the output 
displacement section 37 to move in the arrow A1 direction via the coupling 
tops 70a and 70b. 
At this point, the output displacement section 37, being previously 
adjusted so as to go straight ahead by the straight forwarding means S, 
moves so that the center axis of the output displacement section 37 is 
always on the axis of symmetry 2C. 
The coupling tops 70a and 70b serve to reduce the resistance of the hinges 
and improve the transmitting efficiency. 
The amount of displacement of the piezo-electric element 21 is largely 
enlarged by the law of lever and transmitted to the output displacement 
section 37. Because the lever displacement enlarging mechanisms C, D and E 
are bisymmetrically arranged, the displacement is free from a rotating 
component, having only a component in the direction of the axis of 
symmetry 2C. 
When the applied voltage is brought to null, the apparatus is reset to zero 
by restoring force of the fulcrum, force point and action point hinges of 
the first levers 28a and 28b, the second levers 34a and 34b, and the third 
levers 40a and 40b. 
Opening of the valve is adjusted by driving the output displacement section 
37 while repeating a change in voltage. 
Now, a seventh embodiment of the invention will be described below with 
reference to FIG. 8. This embodiment differs from the sixth embodiment 
(FIG. 7) in that a smooth flat plate 310 is secured to the side wall 60W 
of the block 60, and the ball 301 of the ball plunger 300 is brought into 
contact with the flat plate 310. By so doing, even when irregularities 
occur on the side wall 60W as a result of discharge fabrication or the 
like, the surface in contact with the ball 301 is smooth, and no adverse 
effect is exerted on the rotation of the ball 301. 
There is no particular limitation on the material for the flat plate 301. 
By way of example, a metal plate or a resin plate is also applicable. 
An eighth embodiment will now be described below with reference to FIGS. 9 
and 10. This embodiment has a configuration in which a straight forwarding 
correcting means S is added to the one-stage lever displacement enlarging 
mechanism of the third embodiment (FIG. 4). 
A rectangular plate such as a stainless steel plate P is provided with a 
cut groove H formed through discharge fabrication, laser fabrication, or 
the like, and there are formed a housing portion 102, a screw-tightened 
fixed portion 105, bisymmetrical levers 108a and 108b, a movable portion 
110, bisymmetrical coupling posts 112a and 112b, and an output 
displacement section 117. 
An actuator element 101 is arranged in the housing portion 102, and a lower 
end 101a thereof is pressure-connected to the fixed portion 105 via a 
lower protecting plate 103b. 
The actuator element 101 is an upright actuator element displacing in the 
direction of the axis of symmetry 3C of the plate P, such as a 
piezo-electric, electrostrictive or magnetostrictive element. 
A top end 101b of the actuator element 101 is pressure-connected to the 
movable portion 110 via an upper protecting plate 103a and a wedge plate 
104. 
The wedge plate 104 imparts a preliminary pressure to the piezo-electric 
element and prevents a damage to the piezo-electric element. An 
appropriate preliminary pressure is imparted to the piezo-electric element 
by adjusting the thickness and the amount of pressing of the wedge plate 
104. 
The movable portion 110 is formed into an inverted trapezoid, and 
bisymmetrical force point hinges 113a and 113b are provided at the top 
corners thereof. The force point hinges 113a and 113b are connected to 
bisymmetrically arranged levers 108a and 108b of a lever displacement 
enlarging mechanism F. 
The levers 108a and 108b are bisymmetrically arranged, and connected to an 
output displacement section 117 via bisymmetrical action point hinges 106a 
and 106b and straight forward correcting means S. The center axis of the 
output displacement section is located on the axis of symmetry 3C, and 
output displacement section 117 is connected to a valve rod or the like of 
a micro-flow rate control valve not shown. 
The straight forward correcting means S gives a displacement direction 
correcting force to the hinges of the levers. It adjusts the displacing 
force of the actuator element 101 enlarged via the lever displacement 
enlarging mechanism F to a displacing force in a direction in parallel 
with the axis of symmetry 3C, and cause the output displacement section 
117 to go straight ahead, i.e., to move while always positioning the 
center axis of the output displacement section 117 on the axis of symmetry 
3C. 
For example, a clamping screw 320 is used as the straight forward 
correcting means S. The straight forward correcting means S comprises a 
flat plate 321 of a central projection 110B of the movable portion 110, a 
sliding plate 322 provided slidably relative to the flat plate 321, a 
hemisphere 323 fixed to the sliding plate 322, and a screw 324 in surface 
contact with the hemisphere 323. The flat plate 321 may be omitted. 
The flat plate 321 and the sliding plate 322 are formed of smooth plates, 
and made of such a material as will allow each other's smooth sliding, for 
example, a metal plate, a resin plate, or the like. 
The levers 108a and 108b are connected to top ends of the coupling posts 
112a and 112b via fulcrum hinges 115a and 115b. Leading ends 112e and 112f 
of the coupling posts 112a and 112b face the movable portion 110 via 
boundary grooves 121a and 121b. The leading ends 112e and 112f taper 
toward the ends, and the boundary grooves 121a and 121b diagonally incline 
upward to outside. 
Forming the boundary grooves 121a and 121b as described above provides the 
following advantages: 
(1) The distance between the force point hinges 113a and 113b, on the one 
hand, and the fulcrum hinges 115a and 115b, on the other hand, can be 
reduced, thus leading to an increased lever ratio of the levers 108a and 
108b. 
(2) Elongation caused by deformation of the coupling posts 112a and 112b 
can be reduced. 
(3) The force point hinges 113a and 113b and the fulcrum hinges 115a and 
115b are located closer to outer edges 112c and 112d of the coupling posts 
112a and 112b, and largely apart from the action point hinges 106a and 
106b closer to the axis of symmetry 3C. It is thus available to increase 
the lever ratio. 
Operations of this embodiment will now be described below. 
First, the straight forward correcting means S is adjusted. A mirror is 
arranged at a center portion M of the output displacement section 117. 
While irradiating a light beam in an direction perpendicular to the axis 
of symmetry 3C onto the mirror, the mirror angle is adjusted so that the 
reflected beam is in parallel with the axis of symmetry 3C. Then, the 
actuator element 101 is driven while continuing irradiation, and the 
clamping screw 320 is turned so as to keep always the reflected beam in 
parallel with the axis of symmetry 3C, to apply a displacement direction 
correcting force to the lever hinges of the lever displacement enlarging 
mechanism F. 
When a voltage is applied to the actuator element, for example, the 
piezo-electric element 101, the piezo-electric element 101 elongates in 
the direction of the axis of symmetry 3C in response to the applied 
voltage, thus causing the movable portion 110 to move in the arrow A1 
direction against the preliminary pressure. 
When the movable portion 110 moves in the arrow A1 direction, a force in 
the arrow A1 direction acts on the action point hinges 106a and 106b of 
the levers 108a and 108b via the force point hinges 106a and 106b of the 
lever displacement enlarging mechanism F. As a result, the output 
displacement section 117 moves in the arrow A1 direction. At this point, 
the fulcrum hinges 115a and 115b and the force point hinges 113a and 113b 
are close to each other and are located on the side of the outer edges 
112c and 112d of the coupling posts 112a and 112b, and the action point 
hinges 106a and 106b are located on the side of the axis of symmetry 3C. 
Thus, because all the hinges are symmetrical, the lever ratio is improved, 
and the direction of displacement agrees with the arrow A1 direction in 
parallel with the axis of symmetry 3C. 
At this point, the sliding plate 322 slides on the surface of the flat 
plate 321 in parallel with the axis of symmetry 3C, thus causing the 
output displacement section 117 to go straight ahead. In other words, 
since the direction of displacement is regulated by the straight forward 
correcting means S, the output displacement section 117 goes straight 
ahead while always positioning the center axis thereof on the axis of 
symmetry 3C. 
The amount of displacement of the piezo-electric element 101 is largely 
enlarged by the law of lever, and transmitted to the output displacement 
section 117. Since the lever displacement enlarging mechanism F is 
bisymmetrically arranged with bisymmetrical hinges, the displacement 
contains no rotating component, containing only the component in the 
direction of the axis of symmetry 3C. 
Now, when the applied voltage is brought to null, the apparatus is reset to 
zero by the restoring force of the fulcrum, force point and action point 
hinges of the levers 108a and 108b. 
Opening of the valve is adjusted by driving the output displacement section 
117 while repeating a change in voltage. 
Now, a ninth embodiment will be described below with reference to FIG. 11. 
This embodiment has a configuration in which the straight forward 
correcting means S described in the eighth embodiment (FIGS. 9 and 10) is 
added to the two-stage lever displacement enlarging mechanism of the first 
embodiment (FIGS. 1 and 2). 
A rectangular plate such as a stainless steel plate P is provided with a 
cut groove H formed through discharge fabrication, laser fabrication, or 
the like, and there are formed a housing portion 2, an upper fixed portion 
5, bisymmetrical first levers 8a and 8b, a lower fixed portion 10, 
bisymmetrical coupling posts 12a and 12b, bisymmetrical second levers 14a 
and 14b, and an output displacement section 17. 
An actuator element 1 is arranged in the housing portion 2, and a lower end 
1a is pressure-connected to a push plate 6 via a lower protecting plate 
3b. The actuator element 1 is an upright actuator element displacing in 
the direction of the axis of symmetry 1C of the plate P, such as a 
piezo-electric, electrostrictive or magnetostrictive element. 
The push plate 6 is connected to the bisymmetrical first levers 8a and 8b 
via bisymmetrically arranged force point hinges 7a and 7b of a first lever 
displacement enlarging mechanism A. 
The first levers 8a and 8b are connected to lower ends of the coupling 
posts 12a and 12b bisymmetrically arranged via bisymmetrical action point 
hinges 11a and 11b. The action point hinges 11a and 11b are located closer 
to outer edges 12c and 12d of the coupling posts 12a and 12b. 
The first levers 8a and 8b are connected to the lower fixed portion 10 via 
bisymmetrical fulcrum hinges 9a and 9b. The fulcrum hinges 9a and 9b are 
located closer to the axis of symmetry 1C, and connected sideways to the 
lower fixed portion 10, leading to a small distance between fulcrums and 
force points. As a result, it is available to increase the lever ratio of 
the first levers 8a and 8b, and to downsize the apparatus as a whole. 
Because the fulcrums, the force points and the action points of the first 
levers 8a and 8b are on a straight line L1, the direction of displacement 
is in the direction of the axis of symmetry 1C, and almost no rotating 
component is produced. 
A top end 1b of the actuator element 1 is pressure-connected to the upper 
fixed portion 5 via an upper protecting plate 3a and a wedge plate 4. The 
wedge plate 4 imparts a preliminary pressure to the piezo-electric 
element, and prevents a damage to the piezo-electric element upon 
imparting the preliminary pressure. An appropriate preliminary pressure 
can be imparted to the piezo-electric element by adjusting the thickness 
and the amount of pressing of the wedge plate 4. 
The upper fixed plate 5 is formed into an inverted trapezoid, and 
bisymmetrical upper fulcrum hinges 15a and 15b are provided at top 
corners. The upper fulcrum hinges 15a and 15b are connected to the 
bisymmetrically arranged second levers 14a and 14b of a second lever 
displacement enlarging mechanism B. 
The second levers 14a and 14b are bisymmetrically arranged, and connected 
to the output displacement section 17 via bisymmetrical action point 
hinges 16a and 16b. The center axis of the output displacement section 17 
is located on the axis of symmetry 1C, and the output displacement section 
17 is connected to a valve rod or the like of a micro-flow rate control 
valve not shown. 
The straight forward correcting means S imparts a displacement direction 
correcting force to the hinges of the levers. It adjusts the displacing 
force of the actuator element 101 enlarged via the lever displacement 
enlarging mechanism to a displacing force in a direction in parallel with 
the axis of symmetry 3C, and causes the output displacement section 17 to 
go straight ahead, i.e., to move while always positioning the center axis 
of the output displacement 17 on the axis of symmetry 1C. 
For example, a clamping screw 320 is used as the straight forward 
correcting means S. The clamping screw 320 comprises a flat plate 321 of a 
center projection 17C, a sliding plate 322 provided slidably along the 
flat plate 321, a hemisphere 323 fixed to the sliding plate 322, and a 
screw 324 in surface contact with the hemisphere 323. 
The flat plate 321 and the sliding plate 322 are formed with smooth plates, 
and made of a material allowing smooth mutual sliding, for example, a 
metal plate, a resin plate and the like. 
The second levers 14a and 14b are connected to top ends of the coupling 
posts 12a and 12b via second force point hinges 13a and 13b. Leading end 
parts 12e and 12f of the coupling posts 12a and 12b face the upper fixed 
portion 5 via boundary grooves 21a and 21b. The leading end parts 12e and 
12f taper to the tips, and the boundary grooves 21a and 21b diagonally 
incline upward to outside. 
Forming the boundary grooves 21a and 21b as described above brings about 
the following advantages: 
(1) The distance between the second force point hinges 13a and 13b, on the 
one hand, and the second fulcrum hinges 15a and 15b, on the other hand, 
can be reduced, thus leading to a larger lever ratio of the second levers 
14a and 14b. 
(2) Elongation caused by deformation of the coupling posts 12a and 12b can 
be reduced. 
(3) The second force point hinges 13a and 13b, and the second fulcrum 
hinges 15a and 15b are located closer to the outer edges 12c and 12d of 
the coupling posts 12a and 12b, and largely apart from the action point 
hinges 16a and 16b close to the axis of symmetry C. It is therefore 
available to improve lever ratio. 
Now, operations of this embodiment will be described below. 
First, the straight forward correcting means S is adjusted. A mirror not 
shown is placed at a center portion M of the output displacement section 
17, and while irradiating a light beam in a direction perpendicular to the 
axis of symmetry 1C onto the mirror, the mirror angle is adjusted so that 
the reflected beam is in parallel with the axis of symmetry 1C. 
Then, the subsequent steps comprise driving the actuator element 1 while 
continuing irradiation, and applying a displacement direction correcting 
force to the lever hinges of the lever displacement enlarging mechanisms A 
and B by rotating the clamping screw 320 so as to keep parallelism of the 
reflected beam with the axis of symmetry 1C. 
When a voltage is applied to an actuator element such as a piezo-electric 
element 1, the piezo-electric element 1 elongates in the direction of the 
axis of symmetry 1C in response to the applied voltage, and cause the push 
plate 6 to move in the arrow A2 direction against the preliminary 
pressure. 
When the push plate 6 moves in the arrow A2 direction, a force acts in the 
arrow A2 direction on the first levers 8a and 8b via the force point 
hinges 7a and 7b of the first lever displacement enlarging mechanism A. As 
a result, the levers 8a and 8b cause the coupling posts 12a and 12b to 
move in the arrow A2 direction via the action point hinges 11a and 11b. 
Since movement of the coupling posts 12a and 12b pulls the second force 
point hinges 13a and 13b of the second levers 14a and 14b in the arrow A2 
direction, the output displacement section 17 displaces in the arrow A1 
direction via the second action point hinges 16a and 16b. 
At this point, because the output displacement section 17 has previously 
been adjusted by the straight forward correcting means S so at to go 
straight ahead, it goes straight ahead while always positioning the center 
axis thereof on the axis of symmetry 1C. 
The amount of displacement of the piezo-electric element 1 is largely 
enlarged by the law of lever and transmitted to the output displacement 
section 17. Because the lever displacement enlarging mechanisms A and B 
are bisymmetrically arranged, the displacement contains no rotating 
component, containing only the component in the direction of the axis of 
symmetry 1C. 
The law of lever is exerted while the second fulcrum hinges 15a and 15b and 
the second force point hinges 13a and 13b of the second lever displacement 
enlarging mechanism B move in directions counter to each other, thus 
attaining considerable enlarging of the amount of displacement. 
When the applied voltage is brought to null, the apparatus is reset to zero 
by the restoring force of the respective fulcrum, force point and action 
point hinges of the first levers 8a and 8b and the second levers 14a and 
14b. Opening of the valve is adjusted by driving the output displacement 
section 17 while repeating a change in voltage as described above. 
Now, a tenth embodiment of the invention is illustrated in FIG. 12. This 
embodiment covers a configuration in which, in the three-stage lever 
displacement enlarging mechanism of the sixth embodiment (FIG. 7), the 
ball plunger 300 as a straight forward correcting means S is replaced by a 
clamping screw 320 of the eighth embodiment (FIG. 9). This embodiment, 
corresponding to the sixth and eighth embodiments, will not be described 
here to avoid duplication. In FIG. 12, the same reference numerals as 
those in FIGS. 7 and 9 have the same names and the same functions. 
Industrial Applicability 
The lever displacement enlarging mechanism of the invention is applicable, 
for example, for a positioning apparatus of an optical stage and a 
micro-flow rate control valve (mass-flow controller). It is suitable 
particularly in an apparatus which cannot have a large space for a housing 
portion of the displacement enlarging mechanism in design, and yet is 
required to give a prescribed displacement enlarging ratio, or an 
apparatus required to provide a particularly strict straight forwarding 
property.