JPH11303492A - Hinge device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hinge device capable of stopping at an arbitrary position, at that time, the size of the torque for stopping can be easily adjustable, keeping in a closed state is possible without providing a special lock mechanism, and the opening member can close automatically toward closing position near the closed position. SOLUTION: This hinge device is equipped with a second cam 5 fixed to a first member 23, a first cam 4 attached to the second member 21, exerting means 6 for holding a cam surface 4a of the first cam 4 in a pressured state to a cam surface 5a of the second cam 5, and positioning means 4b, 5b keeping both members 21, 23 in positioning state provided on both cam surfaces 4a, (5a) and mutually linked at a predetermined relative angle position. Also provided are a columnar shaft portion 3 fixed along one of oscillating axis lines of both the members 21, 23 and a plurality of flat plate-shaped, overlapped friction plates 11 made of spring members which are pressured and contacted to the outer peripheral surface of the shaft portion 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hinge device and, more particularly, to a hinge device used for portable equipment such as a portable telephone, an electronic organizer, and a compact cosmetic.

[0002]

2. Description of the Related Art With the development of electronic technology in recent years, various portable devices, such as cellular phones and electronic organizers, equipped with a key panel, a liquid crystal screen, and the like have been developed and widely used. These devices have a size that is easy to use when used, have a compact shape when carried, and accidentally press the key panel or damage the LCD screen in a bag or pocket. To open and close the two members so that there is no
The folding format is adopted.

For example, in a portable telephone, a main body member having operation keys arranged on one surface and a main body member swingably connected to a position where the operation keys are covered when carrying the portable telephone (hereinafter referred to as a closed position). A two-fold type that includes an opening / closing member such as a transmission unit that is folded and arranged at an open position for use (hereinafter referred to as an open position) to enable key operation and to function as a sound collecting member. There is.

[0004] Conventionally, in such a folding type portable article, a hinge type hinge device having a function of merely opening and closing a main body member and an opening / closing member has been used. In a portable article using this type of hinge device, if the user releases the lock mechanism between the main body member and the opening / closing member in the closed position, the user can freely swing the opening / closing member relative to the main body member. It has become.

[0005] A hinge in which a spring for urging an opening / closing member to always open with respect to a main body member is combined with a hinge type hinge device is also employed. In this hinge device, when the user releases the locking mechanism between the main body member and the opening / closing member in the closed position, the opening / closing member is opened by itself with respect to the main body member by the resilient force of the spring, and when closed, the spring is opened. The opening / closing member is pressed in the direction of the main body member against the elastic force to be locked by the lock mechanism.

[0006]

However, the hinge type hinge device which merely swingably connects the opening / closing member and the main body member has the following problems. First
In order to keep the opening / closing member closed with respect to the main body member, an appropriate locking mechanism must be provided, and a projection protruding from the opening / closing member or the main body member is provided. Therefore, there is an inconvenience of being restricted in design and use. Also, by using in combination with any spring member, it is possible to hold the opening and closing member closed in the body member,
In the case of a form product that is opened and used, if the urging force of the spring member is constantly acting during use, the usability is poor.
In addition, providing a special lock member increases the number of parts, and has a disadvantage of increasing the product cost.

Secondly, there is a case where it is desired to adjust the opening / closing angle of the opening / closing member with respect to the main body member to an arbitrary position. In such a case, for example, the position of the transmitting section of the portable telephone is set to an optimum position for the user. It would be convenient if it could be adjusted or the LCD screen of the electronic organizer could be set to the position where the user would most easily see it. However, in the hinge type hinge device, the opening / closing member can only swing freely with respect to the main body member, and the opening / closing member is completely closed with respect to the main body position and the open position where the opening / closing member is completely opened. In order to fix at an arbitrary position between them, there is a disadvantage that a separate fixing means is required.

In order to realize such a function, the opening / closing member is formed of a spring member, is formed in a cylindrical portion having a smaller diameter than the hinge shaft portion, and has a hinge structure in which the cylindrical portion is brought into frictional contact with the shaft portion. However, it is difficult to uniformly apply a frictional force in the length direction of the shaft portion when the molding of the cylindrical portion has a variation.

Further, from the viewpoint of operability, the opening / closing member is automatically closed toward the closed position at a position slightly opened with respect to the main body member, or is opened near the open position. It is convenient if it is configured to automatically move toward. That is, if the opening / closing member can be automatically moved to a position where the opening / closing member is completely closed by closing the opening / closing member with respect to the main body member to a certain extent after the user finishes use, the usability for the user is improved. be able to.

The present invention has been made in view of the above circumstances, and has an opening / closing member that stops at an arbitrary position between a completely closed position and a completely open position with respect to the position of the main body member. In this case, the magnitude of the torque to be stopped can be easily adjusted, the variation in the position where the torque acts in the longitudinal direction of the shaft portion is small, and the opening / closing member is not provided with a special locking mechanism, and the opening / closing member is a main body member. To provide a hinge device that can be held in a closed state with respect to the open / close member, and when the open / close member approaches the closed position, the open / close member automatically closes toward the closed position. .

[0011]

SUMMARY OF THE INVENTION To achieve the above object, the present invention is a hinge device for connecting a first member and a second member so as to be able to swing relative to each other. And the second
A columnar shaft fixed to one of the first member and the second member and fixed to the other of the first member and the second member, A plurality of flat friction plates are provided, and the shaft portion penetrates these friction plates, and each of the friction plates has a hole through which the shaft portion is formed with a smaller diameter than the shaft portion. The spring member has a diameter which is expanded when the portion is press-fitted, and which generates a frictional force with the shaft portion by its restoring force.

In this case, the first member and the second member stop at an arbitrary relative swing angle by a frictional force acting between the outer peripheral surface of the shaft portion and the inner peripheral surface of the hole of the friction plate. Not only is it possible, but by changing the number of friction plates, the magnitude of the overall frictional force can be easily adjusted.

That is, for example, when the number of friction plates is increased, the total contact area between the friction plates and the shaft portion increases, so that the maximum value of the frictional force that can be generated increases, and even if the opening / closing member has a large weight, It is possible to accurately stop at any position. At this time, higher stability of the swing of the opening / closing member is also guaranteed.

Further, by increasing the number of friction plates, the thickness of the entire friction plate is increased, and the supporting portion of the load acting between the main body member and the opening / closing member is increased. Leads to stability. Further, since the processing of the friction plate can be easily performed by punching, the variation in the processing of the cylindrical portion is small. When a slit is formed in the hole,
Elastic deformation of the peripheral portion of the hole is facilitated, and a frictional force can be effectively applied.

Further, a first cam fixed to the first member, a second cam attached to the second member and having a cam surface brought into contact with a cam surface of the first cam,
A rotation locking means for locking the relative rotation of the second cam with respect to the second member, and a state in which both cam surfaces are pressed against each other by urging the cam surface of the second cam toward the cam surface of the first cam. And the first cam and the second cam are provided on cam surfaces of the first cam and the second cam, and are engaged with each other when the first member and the second member are arranged at a predetermined relative angular position. In the case where there is provided at least one pair of concave and convex positioning means for holding both members in the positioning state, the first member is swung relatively to the second member. Then, the first cam attached to the first member is relatively moved with respect to the second cam fixed to the second member. Since the cam surface of the first cam is urged toward the cam surface of the second cam by the operation of the urging means, the cam surface of the first cam is always kept pressed against the cam surface of the second cam. In this case, since the hinge device according to the present invention is provided with the positioning means including the concave portion and the convex portion, the convex portion provided on the other cam surface is provided in the concave portion provided on one of the cam surfaces. Are matched, the concave portion and the convex portion are engaged with each other, so that the second member is relatively positioned with respect to the first member.

That is, when the concave portion and the convex portion are engaged with each other, the first member and the second member are held in a positioning state. The two members can be stopped at the stepless relative swing position by the friction force between the friction plate and the friction plate.

Further, if at least one side of the concave portion in the direction of relative movement with respect to the convex portion is provided with an inclined portion for guiding the convex portion to the engagement position with the concave portion, both cams are relatively moved, When the convex portion approaches the inclined portion immediately before it coincides with the concave portion, the urging force of the urging means guides the convex portion along the slope so as to engage the concave portion.

Further, if a friction plate is used for friction with the shaft portion, it can be easily formed into an arbitrary shape by a punching method, so that a part of the hole fitted into the shaft portion of the friction plate is opened. A notch can be provided at the inner peripheral position of the slit portion to be formed and the hole portion facing the slit portion. In this case, when the convex portion is disposed at the position of the inclined portion, a part of the outer peripheral portion of the shaft portion corresponds to the slit portion of the hole of the friction plate, and another portion corresponds to the notch. Like the friction plate, the shaft,
When the relative position between the first cam and the second cam is set,
The pressure contact state between the friction plate and the shaft is reduced. In particular, when the size and shape of the slit portion and the notch are processed so that the press-contact state is completely released, the configuration is made such that the urging force of the urging means acts in the closing direction. The closing force acting in the direction of relatively closing the first and second members can be applied without a brake by frictional force. That is, in this case, if the first or second member is closed to some extent after the user finishes using the device, the user automatically moves to the completely closed position.

Further, since there is no brake for the closing force by the urging means in the vicinity of the closing position, the closing force can be reduced, and the additional means for generating the closing force can be reduced. In addition, the size of the hinge device can be reduced.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a hinge device according to the present invention will be described below with reference to the drawings. In addition,
In the present embodiment, a hinge device used for an electronic organizer is described as an example.

The hinge device according to the present embodiment is shown in FIG.
As shown in (a) and (b), for example, a fixed-side bracket 2 fixed to a keyboard portion 21 (hereinafter, referred to as a main body member (second member)) of an electronic organizer, and a liquid crystal screen of the electronic organizer A movable bracket 1 fixed to a portion 23 (hereinafter, referred to as an opening / closing member (first member)); a straight rod-shaped shaft 3 fixed to the fixed bracket 2; and a longitudinal direction of the shaft 3 The fixed side cam (second
A fixed cam 5, a movable cam (first cam) 4 fitted to the shaft portion 3 so as to be rotatable around its axis and fixed to the movable bracket 1. An urging means 6 composed of a coil spring that constantly urges the movable portion 4 in the direction of the movable side cam 4 along the axial direction of the shaft portion 3, and is fixed to the movable side bracket 1. A plurality of stacked friction plates 1 for applying a frictional force when rotating
1 is provided.

The fixed cam 5 and the movable cam 4 are
This is a side cam having cam surfaces 5a and 4a that face each other in the axial direction, and is made of, for example, plastic or metal. The fixed side cam 5 is provided with a cam surface 5a on one end surface formed in a substantially cylindrical shape, and a concave portion 5b formed by cutting out a substantially semicircular portion on the cam surface 5a.
And a friction surface 5c adjacent to the recess 5b and formed of a flat surface perpendicular to the axial direction. At the boundary between the concave portion 5b and the friction surface 5c, an inclined surface 5d (inclined portion) is formed so as to smoothly fall from the friction surface 5c toward the concave portion 5b. The cam surface 4a of the movable cam 4 is
It has a convex portion 4b that engages with the concave portion 5b, and is formed in a shape substantially complementary to the cam surface 5a of the fixed side cam 5.
Further, the movable cam 4 is provided with a projection 4c for fixing to the movable bracket 1 described later.

The fixed-side bracket 2 and the movable-side bracket 1 are both formed by bending a thin metal plate by pressing or the like, and the shaft portion 3 is, for example, swaged to the fixed-side bracket 2. Has been fixed by that. A portion of the shaft portion 3 where the fixed side cam 5 is externally fitted is provided with a two-sided portion (rotation locking means) whose side surface is cut out in parallel with the longitudinal direction. The fixed side cam 5 has a center hole having a cross-sectional shape substantially equal to the cross-sectional shape of the shaft portion 3 provided with the two surface portions. Accordingly, the fixed cam 5 externally fitted to the shaft portion 3 is allowed to move in the axial direction with respect to the shaft portion 3, while being relatively rotated around the axis with respect to the shaft portion 3 by the two surface portions. It is held so that it does not rotate.

The portion of the shaft 3 to which the movable cam 4 is fitted has a circular cross section, and the center hole of the movable cam 4 also has a circular cross section. as a result,
The movable cam 4 can rotate around the axis with respect to the shaft portion 3.

As shown in FIG. 2, the friction piece 11 is formed in a substantially C-shaped cross section having a slit portion 11a at a part of the inner peripheral portion, and the shaft portion 3 is not inserted. In the state, the inner diameter is formed to be smaller than the outer dimension of the shaft 3. When the shaft 3 is inserted, the inner diameter of the shaft 3 is increased by expanding the slit portion 11a. It is designed to be pressed against the outer peripheral surface. Further, a notch is formed at an inner peripheral position of the hole facing the slit. On the other hand, the shaft portion has contact portions 3b, 3b in contact with the inner periphery of the hole in the portion inserted through the hole of the friction plate.
And the non-contact portions 3a, 3a are provided in a pair symmetrically with respect to the center of rotation about the point.

In the hinge device according to the present embodiment,
For example, when the hinge device according to the present embodiment is mounted as a hinge device of an electronic organizer, the fixed bracket 2 is fixed to the main body member 21 and the movable bracket 1 is fixed to the opening / closing member 23. These fixings can be performed by any known method. In this case, when the opening / closing member is disposed at a closed position with respect to the main body member, FIG.
As shown in the figure, the convex portion 4b of the movable cam 4 is
Fixed side cam 5 so as to be disposed at an intermediate position on the inclined surface 5d of
The relative positional relationship between the movable cam 4 and the shaft portion 3 around the axis is set.

In the above-described relative positional relationship in which the convex portion 4b of the movable cam 4 approaches the intermediate position of the inclined surface 5d of the fixed cam 5, the shaft portion 3 is positioned at a solid line as shown in FIG. , One short side 3 of the cross section of the shaft 3
The phases thereof are set so that b is located at the notch 11b of the friction plate 11 and the other short side 3b is located at the opening 11a. At this time, the elastic deformation of the friction plate occurring at other positions is almost completely released, and the frictional force is hardly applied between the shaft portion 3 and the friction plate 11, so that a torque-free state is obtained. In this case, the main body member 2
The closing force for swinging 1 in the closing direction does not receive the brake due to the frictional force, and works almost as it is exerted by the urging means. Further, since the initial friction at the time of disengaging the engagement is large, it can be stably stopped at the closed position.

FIG. 4 shows a stopper plate 13 for restricting the rotation range of the shaft. The stopper plate has a projection 13a at a part of a hole through which the shaft is inserted. Further, the shaft portion has a semicircular cross section at a portion inserted into the stopper plate 13 so that the shaft portion can rotate between a position indicated by A in FIG. 4 and a position indicated by B in FIG. In addition, by using the stopper plate, it is impossible to completely rotate at a certain angle or more, and it is possible to prevent the hinge device from being damaged by an excessive opening force.

The operation of the thus constructed hinge device according to this embodiment will be described below. First, for example, when the opening / closing member 23 of the electronic organizer to which the hinge device of the present embodiment is attached is disposed at a position (position I in FIG. 5) closed with respect to the main body member 21, as described above, The convex portion 4b is disposed at an intermediate position on the inclined surface 5d of the cam surface 5a of the fixed cam 5 (see FIG. 3A). In this case, since the fixed cam 5 is constantly urged in the direction of the movable cam 4 by the urging force of the urging means 6, the convex portion 4b is engaged with the concave portion 5b along the inclined surface 5d. Will be guided to.
As a result, in this position I, the torque in the closing direction to the opening / closing member 23 is continuously applied to the opening / closing member 23, and the opening / closing member 23 is closed with respect to the body member 21 without a special lock mechanism. It will be kept in the state where it was.

Next, the opening / closing member 23 is
When the force exceeds the above-mentioned torque generated by the urging means 6, the convex portion 4 of the movable cam 4 is
b is rotated in the direction going up the inclined surface 6d. And
When rotated by a certain angle, the convex portion 4b is disengaged from the inclined surface 5d and rides on the friction surface 5c, so that torque is no longer applied in the direction to close the opening / closing member 23, and the opening / closing member 23 remains in the main body member unless an external force is applied. 21 is held in a stopped state (see position III in FIG. 5 and FIG. 3B).

In this case, in the hinge device according to the present embodiment, since the friction plate 11 is disposed in pressure contact with the outer peripheral surface of the shaft portion 3, a frictional force is generated between the two, and The relative swing operation of the opening / closing member 23 is limited. That is, the opening / closing member 23 is held in a stopped state by the frictional force generated between the shaft portion 3 and the friction plate 11 at an arbitrary relative swing angle position with respect to the main body member 21, and the user's desired (The position between the position II and the position III in FIG. 5) to stop the opening / closing member 23, that is, a so-called free stop mechanism is achieved.

Further, in the hinge device according to the present embodiment, a force is applied in a direction to close the opening / closing member 23 with respect to the main body member 21, and the torque generated by the force is applied to the friction plate 11.
When the torque becomes larger than the torque generated by the frictional force between the shaft member 3 and the shaft member 3, the opening / closing member 23 is swung in a direction to be closed with respect to the main body member 21.

When the movable cam 4 is rotated integrally with the opening / closing member 23 and its convex portion 4b reaches the inclined surface 5d of the fixed cam 5 (position II in FIG. 5 and FIG. 3).
2 (b)), as shown by the solid line in FIG. 2, one short side 3b of the cross section of the shaft portion 3 is notched 11b of the friction plate 11.
And the phases thereof are set such that the other short side 3b is located at the opening 11a, and the pressure contact state between the shaft portion 3 and the friction plate 11 at other positions is almost completely achieved. The frictional force is released between the shaft portion 3 and the friction plate 11 and the torque-free state is established. In this case, the closing force for swinging the main body member in the closing direction acts substantially without being affected by the brake due to the frictional force, with the magnitude exerted by the urging means.

That is, when the convex portion 4b of the movable cam 4 is to be rotated along the inclined surface 5d to the position of engagement with the concave portion 5b, the frictional force that restrains the rotation is released. The rotating operation of the movable cam 4 with respect to the fixed cam 5, that is, the rotating operation of the opening / closing member 23 with respect to the main body member 21 is smoothly performed, and the opening / closing member 23 is moved by the urging force of the urging means 6 in FIG. ), As indicated by the arrow,
It is automatically moved to and held at the closed position (position I) with respect to the main body member 21.

Therefore, according to the hinge device according to the present embodiment, the opening / closing member 23 can be held in a closed state with respect to the main body member 21 without using a special lock mechanism. In addition, a projection which is an obstacle in use is not formed. Further, the opening / closing member 23
When closing the main body member 21 to a certain extent, a torque is generated so as to be automatically closed by the inclined surface 5d of the fixed cam 5 and the biasing means 6, so that the usability is very good. Further, the opening and closing member 23 is connected to the main body member 2.
1 and the shaft 3
The opening / closing member 23 can be held at an arbitrary angular position with respect to the main body member 21 by the frictional force generated between the opening and closing members. Further, since the friction plate 11 is formed of a leaf spring member, the radial dimension around the shaft portion 3 can be minimized, and a device having a small thickness, in particular, a portable device or a portable device which needs to be reduced in weight. Can be applied to supplies.

In addition, the fixed cam is urged toward the movable cam by the urging means, and the fixed cam is provided with a concave portion and the movable cam is provided with a convex portion. May be provided. Furthermore, although the case where the hinge device is used as a hinge device of an electronic organizer has been described as an example, it goes without saying that the hinge device can be incorporated in any other product such as a mobile phone.

Hereinafter, a second embodiment of the present invention will be described with reference to FIG. The hinge device according to the present embodiment includes a fixed-side bracket 15 that can be fixed to a member (not shown), a straight rod-shaped movable shaft 16 that is rotatably supported on the fixed-side bracket 15, and a fixed-side bracket. Fixed to 15,
A plurality of stacked flat friction plates 17 that are in pressure contact with the movable shaft 16 and impart a frictional force when the movable shaft 16 swings are provided.

The main differences from the embodiment of FIG. 1 are that, in FIG. 6, there is no side cam as a positioning means and there is no urging means for pressing the two side cams.

A portion of the movable shaft 16 to which a member (oscillating member) to be swung (not shown) is externally fitted is provided with two face portions (rotation locking means) whose side surfaces are cut out parallel to the longitudinal direction. Have been. Further, the swing member is provided with a center hole having a cross-sectional shape substantially equal to the cross-sectional shape of the movable shaft 16 provided with the two surface portions, which is fitted to the portion provided with the two surface portions of the movable shaft 16. Therefore, the swing member swings with the movable shaft 16 without swinging relative to the movable shaft 16.

In this embodiment, as in the case of the embodiment shown in FIG. 1, the magnitude of the torque is determined by the number of the friction plates and the like, so that the magnitude of the torque can be easily changed by changing the number of the friction plates. Can be adjusted.

[0041]

As described above in detail, the hinge device according to the present invention has the following effects.

(1) The first member and the second member stop at an arbitrary relative swing angle by the frictional force acting between the outer peripheral surface of the shaft portion and the inner peripheral portion of the hole of the friction plate. Not only is it possible, but by changing the number of friction plates, the magnitude of the overall frictional force can be easily adjusted. (2) As a result, it is possible to set the frictional force according to the member, and to have high stability of swinging and stopping of the member. (3) Further, since the friction plate is designed to have a required frictional force even if the friction plate is small, the size of the friction plate can be reduced, so that the entire hinge device can be reduced in size. (4) The opening / closing member can be kept closed with respect to the main body member without providing a special lock mechanism. (5) When the user closes the opening / closing member to a certain extent with respect to the main body member after use, the opening / closing member is automatically moved to a completely closed position, which is convenient.

[Brief description of the drawings]

FIG. 1A is a front view showing an embodiment of a hinge device according to the present invention. (B) It is a top view of FIG.1 (a).

FIG. 2 is an enlarged view showing a friction plate in a state where a shaft of the hinge device of FIG. 1 is press-fitted.

FIG. 3A is an enlarged view for explaining the operation of a cam of the hinge device of FIG. 1; FIG. 3B is an enlarged view similar to FIG. 3A, showing a state in which the movable cam rotates around the shaft.

FIG. 4 is an enlarged view of a stopper plate in the hinge device of FIG.

FIG. 5 is a side view for explaining the operation of the hinge device of FIG. 1;

FIG. 6 is a front view showing another embodiment of the hinge device according to the present invention.

[Explanation of symbols]

 Reference Signs List 1 movable side bracket 2 fixed side bracket 3 shaft 4 movable side cam (first cam) 5 fixed side cam (second cam) 6 biasing means 11 friction plate 11b notch 13 stopper plate 21 body member (second member) 23) Opening / closing member (first member)

Claims (5)

[Claims] 1. A hinge device for connecting a first member and a second member so as to be relatively swingable, wherein the hinge device is arranged along a swing center of the first member and the second member, A columnar shaft portion fixed to one of the first member and the second member, and a plurality of flat friction plates fixed to the other member are provided. The shaft portion penetrates through the friction plates, and each of the friction plates has a hole through which the shaft portion is formed to have a diameter smaller than that of the shaft portion. A hinge device, wherein the hinge device is a spring member that generates a frictional force between the shaft portion and the shaft portion by a force. 2. The hinge device according to claim 1, wherein the friction plate is provided with a slit that opens a part of the hole. 3. The hinge device is further attached to a first cam fixed to the first member and to the second member, and is brought into contact with a cam surface of the first cam. A second cam having a cam surface; rotation locking means for locking relative rotation of the second cam with respect to the second member; and a cam surface of the first cam, the cam surface of the second cam. Urging means for urging toward the surfaces to hold the two cam surfaces in a pressed state, and provided on the cam surfaces of the first and second cams, wherein the first member and the second member are provided in a predetermined manner. A positioning means comprising at least one pair of a concave portion and a convex portion, which are engaged with each other when they are arranged at the relative angular positions, and hold both members in a positioning state. The hinge device according to claim 2. 4. A method according to claim 1, further comprising an inclined portion on at least one side of the concave portion in a direction of relative movement with respect to the convex portion, the inclined portion being configured to guide the convex portion to an engagement position with the concave portion. The hinge device according to claim 3, wherein 5. A notch is formed in the friction plate at an inner circumferential position of the hole facing the slit, and a contact portion in contact with an inner circumference of the hole is formed on an outer circumferential portion of the shaft. And a pair of non-contact portions are provided symmetrically about the center of rotation with respect to a point of rotation, and when the convex portion is disposed at the position of the inclined portion, the contact portion of the shaft portion cuts off the slit portion of the friction plate. The hinge device according to claim 4, wherein relative positions of the friction plate, the shaft portion, the first cam, and the second cam are set so as to be arranged in the notch.