JPH10115848A - Shutter for camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a shutter for a camera constituted so that the releasing action of a shutter device is driven by a motor without using electromagnetic parts and optimally designed in order to be miniaturized and driven by the motor. SOLUTION: A driving member for a first blade 2 and a driving member for a second blade 3 are actuated toward a set position by rotating a set member 19 clockwise. Then, the set member 19 is locked at the set position by a lock member 10. Besides, wirelike shape memory alloys 12 and 21 are respectively arranged in grooves 1g and 1h formed on a shutter bottom board 1. Then, one ends thereof are respectively fitted to the lock member 10 and the set member 19 and the other ends are fitted to the board 1. The alloys 12 and 21 are formed so that the length thereof is shortened when a voltage is impressed on both ends thereof. By the alloy 21, the set member 19 is actuated toward the set position. By the alloy 12, the lock of the set member 19 is released by actuating the lock member 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a camera shutter provided with a motorized device suitable for downsizing a camera.

[0002]

2. Description of the Related Art Recently, demands for downsizing and motorization of cameras have been further increased, and various proposals have been made and implemented in order to meet the demands. Among them, regarding motorization, the film winding operation has been automatically performed by a motor, and the lens has also been moved by a motor to automatically perform focus adjustment. In addition, as for the shutter device, the electrification has been advanced, and not only the set operation but also the release operation have been performed electrically. As a result, by electrifying the release operation, the shutter device can be released immediately after the automatic focus adjustment is performed, and advantages such as less missed shutter chances can be obtained. ,
The merit that the setting operation is not required to be performed at all by using the motorized setting operation has come to be obtained.

[0003]

On the other hand, there is an extremely strong demand for miniaturization, especially with the advent of the IX240 cartridge film (Advanced Photo System Film), which has been further spurred. However, if the shutter device is electrified as described above, the size of the camera is inevitably increased, which is contrary to the demand for downsizing. That is, it is common to use an electromagnet or a plunger for the release operation of the shutter device. However, even if these components are small, they are considerably large as camera components, and have a three-dimensional shape. Therefore, it is very difficult to pack them together with other parts. In addition, when the shutter device is set electrically, the motor is driven in conjunction with the film winding. Therefore, even if the motor can be used in common, an interlocking mechanism is required. Is greatly restricted.

The present invention has been made to solve such a problem, and an object of the present invention is to use a shape memory alloy as a driving source without using the above-described electromagnet or plunger, and to provide a shutter device. An object of the present invention is to provide a shutter for a camera which is optimal for miniaturization and motorization for performing a release. Further, another object of the present invention is to provide a camera suitable for miniaturization and motorization in which the shutter device is set and released by using two shape memory alloys as driving sources without using the above-described electromagnetic components. To provide a shutter for use.

[0005]

In order to achieve the above object, a camera shutter according to the present invention comprises a base plate having an opening for exposure, a driving spring for reciprocating operation, and a driving spring for leading blades at the time of exposure operation. A driving member for the front blade that is operated from the set position to open the opening for exposure to the front blade, and the driving member for the front blade is held at the set position, and the holding force is controlled according to a signal from the exposure time control circuit. Holding means for the front blade to be released, a driving member for the rear blade capable of reciprocating operation and being operated from a set position by a driving spring for the rear blade at the time of the exposure operation to close the exposure opening to the rear blade, and A rear blade holding means for holding the blade driving member at the set position and releasing the holding force in response to a signal from the exposure time control circuit, and capable of reciprocating operation and resisting its own operation behavior from the initial position. A set member that is actuated to move the leading blade drive member and the trailing blade drive member to a set position against the respective drive springs; a locking member that locks the set member at the set position; A shape memory alloy that is attached to the locking member and the other end is attached to the base plate, and that when the voltage is applied to both ends, activates the locking member to release the locking of the set member. ing.

In the camera shutter according to the present invention, preferably, both ends of the shape memory alloy are attached to the base plate, and the both ends are hung on the locking member. In the camera shutter of the present invention, preferably, one end is attached to the set member, and the other end is attached to the base plate, and when a voltage is applied to both ends, the set member is moved to the set position. A second shape memory alloy to be provided. Further, in the camera shutter of the present invention, preferably, both ends of the second shape memory alloy are attached to the base plate, and the both ends are hung on the set member.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described with reference to a first embodiment shown in FIGS. 1 to 4 and a second embodiment shown in FIGS. FIG. 1 is a plan view showing a state before setting immediately after the photographing of the first embodiment, and FIG. 2 is a sectional view taken along line AA of FIG. FIG. 3 is a plan view showing a state of the first embodiment after setting, and FIG. 4 is a timing chart for explaining the operation of the first embodiment. FIG. 5 is a plan view showing a state immediately before the end of shooting in the second embodiment before setting, and FIG. 6 is a sectional view taken along line BB of FIG. FIG. 7 is a partial side view of a main part of the second embodiment, and FIG. 8 is a plan view showing a state after setting of the second embodiment.

First, the structure of the first embodiment will be described.
In this embodiment, the present invention is applied to a focal plane shutter. As is well known, the shutter base plate 1 made of synthetic resin is formed with an exposure opening 1a at a substantially central portion, but only the left part thereof is shown in the drawing. On the back side of the shutter base plate 1, as is well known,
At predetermined intervals, an intermediate plate and a cover plate (not shown) are sequentially attached. An opening having a shape similar to that of the opening 1a is also formed in the intermediate plate and the cover plate, and an exposure opening as a shutter unit is determined by combining these three openings. In the case of the present embodiment, the leading blade is arranged between the shutter base plate 1 and the intermediate plate, and the trailing blade is arranged between the intermediate plate and the cover plate.

A shaft 1 is provided on the front side of the shutter base plate 1.
b, 1c, and 1d are erected, and the shafts 1b, 1
c also protrudes to the back side of the shutter base plate 1, and the portion is formed thin. Although not shown because it is well known, the front blade and the rear blade in the present embodiment each have a configuration in which a plurality of divided blades are pivotally supported on two arms pivotally mounted on the rear side of the shutter base plate 1. Each of the arms (hereinafter, referred to as a main arm) is pivotally connected to the shafts 1b and 1c. The shutter base plate 1 has penetrated arc-shaped holes 1e and 1f formed thereon, and further has a linear groove 1g and an L-shaped groove 1h formed on the surface. And, at the bottom of this groove 1g, two guide portions 1 each having a kamaboko-shaped cross section are provided.
i are formed, and two guides 1j of the same shape are also formed at the bottom of the groove 1h. Further, a shaft-shaped guide portion 1k having an arc surface is formed at the bent portion of the groove 1h so as to increase the radius of curvature. As can be seen from FIG.
An overhang 1m on the front side so as to cover the guide 1k
Is formed, and a hole 1n is formed on the back side. Further, in the vicinity of the overhang portion 1m, a part of the groove 1h is covered from the opposite side in FIG.
p is formed.

On the front side of the shutter base plate 1, the shaft 1
A driving member 2 for the front blade and a driving member 3 for the rear blade made of synthetic resin are rotatably attached to b and 1c. These driving members 2 and 3 are provided with operating pins 2a and 3a and mounting portions 2b and 3b, respectively, and rollers 2c and 3c are rotatably mounted. Of these, the operating pins 2a,
3a penetrates through the arc-shaped holes 1e and 1f, and is fitted into holes formed in each main arm of the leading blade and the trailing blade. Therefore, when the leading blade drive member 2 rotates counterclockwise, the operating pin 2a operates the main arm in the counterclockwise direction to deploy the divided blades, and when rotated in the clockwise direction, the operating pin 2a Is operated clockwise to overlap the divided blades. On the other hand, when the rear blade driving member 3 rotates counterclockwise, the operating pin 3a operates the main arm in the counterclockwise direction to overlap the divided blades, and the operating pin 3a operates the main arm in the clockwise direction. Sometimes the split blades are deployed.

Also, the mounting portions 2b, 3 of the driving members 2, 3
b is formed so as to protrude to the near side in FIG. 1, and the iron piece members 4 and 5 are attached thereto, respectively.
In order to clarify the specific mounting configuration, FIG. 1 and FIG. 3 show the portion in cross section. The iron piece members 4 and 5 are composed of iron pieces 4a and 5a to be attracted to an electromagnet, shafts 4b and 5b loosely fitted into holes formed in the mounting portions 2b and 3b, and a flange 4c. 5c, and can move in the axial direction of the shafts 4b and 5b. Then, the iron pieces 4a, 5a and the mounting portion 2
Compression springs 6 and 7 are interposed between b and 3b, and urge the flanges 4c and 5c to come into contact with the mounting portions 2b and 3b. The front blade drive member 2 and the rear blade drive member 3 are urged to rotate clockwise by a front blade drive spring 8 and a rear blade drive spring 9, respectively. , 9 are connected to the mounting portions 2b, 3 described above.
The other end is hung on the spring hooks 1q and 1r of the shutter base plate 1.

A locking member 10 is further rotatably mounted on the shaft 1c of the shutter base plate 1. The locking member 10 has a thick portion 10a and a hook portion 10b, and the thick portion 10 faces the groove 1g. The locking member 10 is urged by a spring 11 to rotate in a counterclockwise direction, and the rotation is prevented by a stopper 1s. A wire-shaped shape memory alloy 12 is arranged in the groove 1g, and one end of the wire is stored in the groove 1g.
g, and the other end is attached to the thick portion 10a. The respective mounting methods are the same, and each end is swaged so as to be wound around the stoppers 13 and 14, and the stoppers 13 and 14 are fixed by screws 15 and 16. As is well known, when a voltage is applied to both ends of this type of shape memory alloy, its length shrinks,
It has the property of returning to its original state when cooled. Therefore, in this embodiment, the lead wires 17 and 18 are also
Together with the stoppers 13 and 14.

A set member 19 made of a synthetic resin is rotatably attached to the shaft 1d of the shutter base plate 1, and is urged by a spring 20 to rotate counterclockwise. The spring 20 has one end connected to the set member 19.
And the other end is hooked on a spring hook 1t provided on the shutter base plate 1. Also, the set member 19 has two cam-shaped pushing portions 19b, 19b.
c is formed, and the engagement portion 19d is formed by further increasing the thickness of the end of the pushing portion 19b. A thick portion 19e is formed on the back side of the set member 19, and faces the groove 1h. A wire-shaped shape memory alloy 21 is disposed in the groove 1h, one end of which is attached to the groove 1h and the other end is attached to the thick portion 19e. The respective mounting methods are the same as in the case of the shape memory alloy 12 described above, and the ends are wound around the stoppers 24 and 25 together with the lead wires 22 and 23, and the crimping is performed. , 25 with screw 26,
27.

Although not shown because it is well known, a mounting plate (sometimes referred to as an upper base plate) is mounted on the front side of the shutter base plate 1 so as to be parallel to the shutter base plate 1. . The electromagnet 28 for the front blade and the electromagnet 29 for the rear blade are provided on the lower surface, that is, the surface on the shutter base plate 1 side.
And are attached. Therefore, in FIGS. 1 and 3, those electromagnets 28 and 29 are indicated by dashed lines. The electromagnets 28 and 29 in the present embodiment are
8a and 29a are U-shaped so that the iron pieces 4 and 5 are attracted by the two magnetic pole portions, respectively, and each of the magnetic pole portions has a configuration in which coils 28b and 29b are wound around one of the magnetic pole portions. . However, since the two magnetic pole portions of the iron core members 28a and 29a are arranged so as to be perpendicular to the shutter base plate 1, only one of the magnetic pole portions is visible in the drawing.

Next, the operation of this embodiment will be described with reference to FIG. FIG. 1 shows a state immediately after the end of shooting. Therefore, the front blade drive member 2 and the rear blade drive member 3
Means that the exposure operation has been completed by the respective drive springs 8 and 9, and the photographer is still holding down the release button of the camera. In this state, the divided blades of the leading blade (not shown) overlap with each other to expose the opening 1a for exposure.
The split blade of the rear blade is expanded to cover the exposure opening 1a, and the set member 19
Is returned to the initial position by the spring 20. The initial position of the set member 19 may be regulated by a stopper, but in the present embodiment, is regulated by the length of the shape memory alloy 21.

In this state, when the pressing force of the release button is released, the power switch SW is turned off. However, even if the power switch SW is turned off, the film winding motor Mo and the shape memory alloy 21 (FIG.
Since the power can be supplied to SMA2), the film is wound by the OFF signal of the power switch SW, and at the same time, the voltage is applied to the shape memory alloy 21. Therefore, the shape memory alloy 21 contracts rapidly and becomes short, and rotates the setting member 19 in the clockwise direction against the spring 20. By this rotation, first, the pressing member 19b of the setting member 19 presses the roller 2c, which is the pressed member. Therefore, the leading blade driving member 2 rotates counterclockwise against the leading blade driving spring 8, and the main arm of the leading blade (not shown) is rotated counterclockwise about the shaft 1b by the operating pin 2a. Let it. As a result, the split blade (not shown) starts to operate upward while being deployed, but when a part of the slit forming blade overlaps the slit forming blade of the rear blade by a predetermined amount, the other of the set member 19 is set. The pushing portion 19c is provided with the roller 3 of the driving member 3 for the rear blade.
Start pressing c.

In this manner, the roller 3c is moved
When the rear blade drive member 3 is pressed counterclockwise against the drive spring 9, the operating pin 3a causes the main arm of the rear blade (not shown) to rotate counterclockwise with the shaft 1c. Rotate. As a result, the split blades of the rear blade operate upward while overlapping. When the setting member 19 further rotates, the engaging portion 19d pushes the back of the hook portion 10b of the locking member 10, and rotates the locking member 10 clockwise against the spring 11. Immediately thereafter, the shingle part 4 of the shingle members 4 and 5
a, 5a successively contact the iron core members 28a, 29a. Then, at the stage where the back of the engaging portion 19d of the set member 19 and the hook portion 10b of the locking member 10 is released,
When the contraction of the shape memory alloy 21 ends (a stopper may be provided for the clockwise rotation of the set member 19), the set member 19 stops. Therefore, the hook portion 10b of the locking member 10 returns to the operating locus of the engaging portion 19d by the spring 11. The state at that time is shown in FIG.

At this time, the iron piece portions 4a,
5a is in close contact with the iron core members 28a, 29a, and the compression springs 6, 7 are compressed.
c, 5c and the mounting portions 2b, 3b are in a non-contact state. In addition, the leading blade is in a developed state, and the exposure opening 1a is formed.
And the rear blades are stored in a superimposed state at a position above the exposure opening 1a. After the shutter has been set in this way, the application of the voltage to the shape memory alloy 21 is stopped, and when the film winding operation is completed, the camera is ready for the next photographing.

When the application of the voltage is stopped, the shape memory alloy 21 is stretched, but the set member 19 is
So that it does not rotate counterclockwise. In addition, the shape memory alloy 21 is thereby loosened by an amount corresponding to the extension, but since the overhang portions 1m and 1p are formed at the close positions from the opposite side, the shape memory alloy 21 is detached from the guide portion 1k. There is nothing. In order to prevent the shape memory alloy 21 from going out of the groove 1h, the number of such overhangs 1m and 1p may be increased as necessary.

Next, the release operation will be described. When the release button of the camera is pressed, the power switch SW is closed in the initial stage, the photometry circuit and the distance measurement circuit operate, and both the coils 28 of the electromagnet 28 for the front blade and the electromagnet 29 for the rear blade
b, 29b are energized, and the iron core members 28a, 29a are excited. Therefore, the iron piece portions 4a,
5a is magnetically attracted to the iron core members 28a and 29a.
At this stage, the photographer can confirm the suitability of the photographing conditions and the like using a known display device. Thereafter, when the release button is further pressed, the lens is extended based on the distance measurement result, and substantially simultaneously with the stop thereof, the shape memory alloy 12 is released.
The voltage is applied to (symbol SMA1 in FIG. 4).
As a result, the shape memory alloy 12 contracts and the locking member 10
Is rotated clockwise against the spring 11. As a result, the hook portion 10b of the locking member 10 is disengaged from the engaging portion 19d, and the set member 19 is returned to the initial position shown in FIG. The exposure time control circuit is triggered in conjunction with the returning operation of the setting member 19.

When the exposure time control circuit is triggered and a predetermined delay time has elapsed, the coil 2 of the electromagnet 28
8b is cut off. As a result, the leading blade drive member 2 rotates clockwise by the force of the leading blade drive spring 8, and operates the main arm of the leading blade clockwise by the operating pin 2a. Therefore, the plurality of divided blades constituting the leading blade are superimposed and open the exposure opening 1a. Then, immediately after the opening, the operating pin 2a
Collides with the lower edge of the hole 1e, is prevented from bouncing by means not shown, is stored at a position below the exposure opening 1a, and stops.

After a predetermined time corresponding to the photometric result after the energization of the coil 28a of the electromagnet 28 for the front blade is cut off, the energization of the coil 29b of the electromagnet 29 for the rear blade is cut off. Therefore, the biasing force of the rear blade drive spring 9 rotates the rear blade drive member 3 clockwise, and the operating pin 3a operates the main arm of the rear blade clockwise.
As a result, the plurality of divided blades constituting the rear blade group are developed and close the exposure opening 1a. Immediately after the closing, the operating pin 3a collides with the lower end edge of the hole 1f, the bouncing is prevented by means not shown, and the operation pin 3a stops while covering the exposure opening 1a. The state at this time is the state shown in FIG.

Next, a second embodiment of the present invention shown in FIGS. 5 to 8 will be described. Since the configuration of the present embodiment is almost the same as the configuration of the first embodiment, in the drawings, parts or portions that are completely the same or substantially the same are denoted by the same reference numerals as those used in the first embodiment. They have the same reference numerals. Therefore, in the description of the present embodiment, points different from the first embodiment will be described, and description of the same points will be omitted.

First, in this embodiment, the grooves 1g, 1h
Is different from that of the first embodiment. In particular, the groove 1h is configured to be divided into two parts in the middle, and two bent parts are provided. Therefore, two axial guides 1k, overhangs 1m, holes 1n, and overhangs 1p are provided, and two guides 1j are formed at the bottom of the groove 1h. One is provided.

In this embodiment, as can be seen from FIG. 6, a shaft portion 10c and a flange portion 10d are formed on a thick portion 10a of the locking member 10. Both ends of the shape memory alloy 12 are mounted in the groove 1g, and a substantially middle portion thereof is hung on the shaft portion 10c. Further, the set member 19 of this embodiment has the pin 1 facing the groove 1h.
9f is erected. As can be seen from the side view of FIG. 7, this pin 19f is formed with a hole 19g penetrating in the radial direction, and both outlets are formed with chamfers. Both ends of the shape memory alloy 21 are mounted in the groove 1h, and a substantially middle portion thereof is inserted into the hole 19g.

As described above, in this embodiment, the shape memory alloy 1
The only difference from the first embodiment is that one ends of the members 2 and 21 are slidably hung on the locking member 10 and the set member 19. Therefore, the operation of the shutter device is substantially the same as that of the first embodiment.
5 and 8 show states corresponding to FIG. 3 and FIG. 3, respectively, and a description thereof will be omitted.

In this embodiment, if the shrinkage ratios of the shape memory alloys 12 and 21 are the same as in the first embodiment, the first
The length of the shape memory alloys 12 and 21 is required to be about twice as long as the configuration of the embodiment. However, even if it is long, it can be arranged in the grooves 1g and 1h, and even if it is not arranged in the grooves 1g and 1h, it should be arranged along the shutter base plate 1 so as not to hinder the operation. Is possible. Further, in the case of the second embodiment, since all the connecting portions to the lead wires 17, 18, 22, and 23 are fixed to the shutter base plate 1, the connection is performed by operating as in the case of the first embodiment. There is no worry that the part will break or break.

As described above, according to each of the above embodiments,
A conventional three-dimensional electromagnet or plunger is not used to release the shutter. Also, when setting, there is no mechanical interlocking with the film winding mechanism as in the related art, and no unique motor is used. Therefore, the space in the camera can be used freely,
The configuration is suitable for downsizing the camera. Further, the shape memory alloys 12 and 21 are provided with the grooves 1g and 1h
, Which has little effect on the arrangement and operation of the conventional shutter configuration. Furthermore, since the shape memory alloys 12, 21 expand and contract under the conditions of low resistance due to the guide portions 1i, 1j formed in the grooves 1g, 1h, the power consumption can be reduced.

Although the wire-shaped shape memory alloys 12 and 21 are used in each of the above embodiments, a strip-shaped shape memory alloy may be used. In addition, locking member 1
Since the working stroke of 0 may be relatively small,
In some cases, the shape memory alloy 12 does not need to be in the form of a string. In addition, a shape memory alloy that expands when a voltage is applied is used, and the locking member 10 is pressed against the spring 11. It does not matter.

Each of the above embodiments is an embodiment in which the present invention is applied to a focal plane shutter.
Needless to say, the present invention can also be applied to a lens shutter of a type in which a front blade or opening blade and a rear blade or closing blade are separately provided. Further, in that case, each blade may be a single blade or a plurality of blades.

[0031]

As described above, according to the present invention, since the shape memory alloy is used as a drive source to release the shutter, a conventional three-dimensionally shaped electromagnet or plunger is used. As compared with the case, the space in the camera can be freely used, which is most suitable for downsizing the camera. Also,
If another shape memory alloy is used as the drive source when setting the shutter, it is not necessary to mechanically link the film winding mechanism as in the past, or use a unique motor. The use of the space in the camera is greatly freed, and the size is further reduced.

[Brief description of the drawings]

FIG. 1 is a plan view of a first embodiment of the present invention, showing a state before setting immediately after photographing is completed.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a plan view showing a state after setting in the first embodiment.

FIG. 4 is a timing chart for explaining the operation of the first embodiment.

FIG. 5 is a plan view of a second embodiment of the present invention, showing a state before setting immediately after the end of photographing.

FIG. 6 is a sectional view taken along line BB of FIG. 5;

FIG. 7 is a partial side view of a main part of the second embodiment.

FIG. 8 is a plan view showing a state after setting in the second embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Shutter base plate 1a Exposure opening 1b, 1c, 1d Axis 1e, 1f, 1n, 19g Hole 1g, 1h Groove 1i, 1j, 1k Guide 1m, 1p Overhang 1q, 1r, 1t, 19a Spring hook 1s Stopper 2 Front blade drive member 2a, 3a Operating pin 2b, 3b Attachment part 2c, 3c Roller 3 Rear blade drive member 4, 5 Iron piece member 4a, 5a Iron piece part 4b, 5b, 10c Shaft part 4c, 5c, 10d Flange part 6, 7 Compression spring 8 Drive spring for leading blade 9 Drive spring for trailing blade 10 Locking member 10a, 19e Thick portion 10b Hook portion 11, 20 Spring 12, 21, Shape memory alloy 13, 14, 24, 25 Stopper 15 , 16, 26, 27 Screw 17, 18, 22, 23 Lead wire 19 Set member 19b, 19c Pushing portion 19d Engaging portion 19f Pin 28 Electromagnet for leading blade 8a, 29a iron core member 28b, the magnetic bearing blade trailing 29b coil 29

Claims (4)

[Claims] 1. A base plate having an exposure opening, and a front blade drive that is reciprocally operable and is operated from a set position by a front blade driving spring during the exposure operation to open the exposure opening to the front blade. A holding member for holding the front blade driving member at a set position and releasing the holding force in response to a signal from an exposure time control circuit; and a rear blade capable of reciprocating operation during the exposure operation. A driving member for the rear blade, which is actuated from the set position by the driving spring for closing the opening for exposure to the rear blade, holding the driving member for the rear blade at the set position and responding to a signal from an exposure time control circuit. A rear blade holding means for releasing the holding force; and a reciprocating operation capable of operating the front blade driving member and the rear blade driving member from the initial position and being actuated against its own operation habit. Against the spring A set member that operates to the set position, a lock member that locks the set member at the set position, and one end attached to the lock member and the other end attached to the base plate, and a voltage is applied to both ends. And a shape memory alloy for operating the locking member to release the locking of the set member when the shutter is released. 2. The camera shutter according to claim 1, wherein both ends of the shape memory alloy are attached to the main plate, and the both ends are hung on the locking member. 3. A second shape memory alloy having one end attached to the set member and the other end attached to the base plate, the second shape memory alloy actuating the set member to a set position when a voltage is applied to both ends. The camera shutter according to claim 1, wherein: 4. The camera shutter according to claim 3, wherein both ends of the second shape memory alloy are attached to the base plate, and the both ends are hung on the set member.