JPH0740980Y2 - Shock buffer mechanism - Google Patents

Description

[Detailed description of the device] [Industrial applications]

The present invention relates to a shock absorbing mechanism that absorbs a shock generated when a side edge of a movable member collides with a stopper disposed at a movement end position of a reciprocating thin plate-shaped movable member, and for example, at a high speed like a focal plane shutter. The present invention relates to an optimum shock absorbing mechanism for absorbing a shock of a thin plate-shaped movable member that has a large number of required guarantees of durability and has a low torsional strength, in which a large shock is generated at the time of collision with a stopper during traveling.

2. Description of the Related Art A conventional shock absorbing mechanism for stopping a blade driving arm for driving a focal plane shutter, which is an example of a thin plate-like movable member, at its advance end will be described with reference to FIG. In FIG. 6, a blade driving arm 1 which is a thin plate-shaped movable member for driving the leading blade is shown as a shaft 2a on the shutter base plate 2.
Is swingably supported by the shaft of the blade drive arm 1.
Each of the blades 1a, 1b, 1c, 1d, and 1e supports a blade (not shown) that constitutes a leading blade. The shapes of these blades are well known in the art. Next, 3 is a buffer member fixed to the shutter base plate 1 by a shaft 4, and the buffer member 3 is an advance end of the blade drive arm 1 (the advance direction of the blade drive arm 1 is indicated by an arrow A
Direction. ), The blade drive arm 1 comes into contact with the cushioning member 3 and stops when the leading blade travels.

[Problems to be solved by the device]

In the case of the shock absorbing mechanism having the above structure, since the blade driving arm 1 which is a thin plate-shaped movable member always collides with the same position of the buffering member 3, the traveling speed of the blade driving arm 1 is particularly increased. In such a case, there is a problem that the shock-absorbing member is likely to be permanently deformed and its durability is lowered. Further, due to permanent deformation and wear of the cushioning member, the vane may overrun a predetermined stopping position, resulting in deterioration of accuracy of the stop point, and in some cases, the vane may collide with the camera body. There is also the possibility of failure. Further, a thin plate-shaped movable member such as a blade drive arm has a low twist strength, and depending on the structure of the shock absorbing mechanism, the twist of the movable member may cause light leakage of the aperture. Of course, if a material with high impact resilience is used for the cushioning member 3,
Although the durability of the cushioning member 3 is improved, in that case, there is a problem that the shock absorbing performance is deteriorated and the movable member bounces at the advanced end.

[Means for solving problems]

The present invention has been made in order to solve such a problem. A shock absorbing member is provided which improves the durability of the shock absorbing member while using a shock absorbing member made of a material having low impact resilience and high shock absorbing power. The purpose is to provide a mechanism. In summary, the shock absorbing mechanism of the present invention comprises: a reciprocating thin plate-like movable member having an elastic cushioning member arranged at one end of one direction of movement, and a side edge of the movable member finally forming the cushioning member. Assuming a shock-cushioning mechanism that absorbs the shock generated at the time of collision by elastic deformation of the shock-absorbing member: the outer peripheral surface of the shock-absorbing member is formed into a circular shape, and
The cushioning member is rotatably supported about the circular center of the outer peripheral surface as a rotation axis: a final contact surface that finally collides with the cushioning member at the end of the operation, and a final contact surface on the side edge of the movable member. Before the surface collides with the buffer member, it contacts the outer peripheral surface of the buffer member to apply a rotational force to the buffer member and also contacts the outer peripheral surface of the buffer member during the returning process of the movable member. A front abutment surface for applying a rotational force in the opposite direction to the member: the final abutment surface is formed before the rotation of the cushioning member naturally stops when the front abutment surface comes into contact with the cushioning member. It is characterized in that the positions of the front-stage contact surface and the final contact surface are associated with each other so as to contact the buffer member and stop the rotation of the buffer member.

[Action]

That is, according to the shock absorbing mechanism of the present invention, in the advance stroke of the thin plate-shaped movable member, the final contact surface formed on the side edge of the movable member comes into contact with the buffer member to stop the movable member. Before the abutment surface abuts the cushioning member, the front abutment surface also formed on the side edge of the movable member abuts the cushioning member to rotate the cushioning member. Then, before the rotation of the cushioning member naturally stops, the final contact surface comes into contact with the cushioning member to stop the rotation of the cushioning member. On the other hand, even in the return stroke of the movable member, the cushioning member rotates due to the contact between the front contact surface and the cushioning member. This rotation is caused by the frictional resistance generated between the bearing portion of the cushioning member and the cushioning member. Since the operation continues until the stop, the rotation amount of the cushioning member in the advance stroke of the movable member and the rotation amount of the cushioning member in the return stroke of the movable member differ.
Therefore, since the entire circumference of the rotatable cushioning member is evenly used for absorbing the shock, even if a material having a large shock absorbing capacity is used as the cushioning member, the conventional cushioning member is partially used. The durability of the cushioning member is significantly improved as compared with the above case. Further, since the front contact surface and the final contact surface are formed on the side edges of the thin plate-shaped movable member and are not offset from the operation line of the movable member at all, the front contact surface and the final contact surface are buffered. The force in the twisting direction is not applied to the movable member when it collides with the member, and it is not necessary to secure a space for securing the traveling path of the front contact surface and the final contact surface.

【Example】

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. 1 and 2 are front views showing a front curtain drive mechanism of a focal plane shutter which is one application example of the shock absorbing mechanism according to the present invention, and FIG. 1 shows a shutter closed state,
FIG. 2 shows the shutter opening state. A blade drive arm 11, 12, which is an example of a thin plate-shaped movable member pivotally supported by shafts 10a, 10b on the shutter base plate 10 so as to be swingable.
Shafts 11a, 11b, 11c, 11d, 11e and shafts 12a, 12b, 1 respectively
2c · 12d · 12e are provided, these shafts 11a · 11b · 11c · 1
The blades 13a, 13b, 13c, 13d, and 13e forming the front curtain are rotationally swaged on the shafts 1d and 11e and the shafts 12a, 12b, 12c, 12d, and 12e. A guide groove 10c in an arc centered on the shaft 10a is formed on the shutter base plate 10, and an output pin of an actuator (not shown) protruding from the guide groove 10c engages with a long hole 11f formed on the blade drive arm 11. I am fit. When the output pin is moved along the guide groove 10c, the blade drive arm 1
1/12 swings clockwise in the drawing, and blades 13a / 13b / 1
3c, 13d, and 13e open the aperture 10d. (State shown in FIG. 2) The cushioning member 14, which is a feature of the present invention, is arranged so as to regulate the advance end of the blade drive arm 11 which is an example of a movable member. A description will be given with reference to FIG. 4, FIG. 4 and FIG. The buffer member 14 formed in a circular shape is used for the shaft 10 on the shutter base plate 10.
It is rotatably supported by e. Also, the blade drive arm 11
At the side edge of the blade, a final contact surface for finally contacting and stopping the cushioning member 14 during the advance stroke of the blade drive arm 11.
11g is formed, and a front contact surface 11h that contacts the shock absorbing member 14 before the final contact surface 11g contacts the shock absorbing member 14 when the blade drive arm 11 advances is formed. As a feature of the present invention, the central axis of the cushioning member 14 is arranged at a position offset by a radius corresponding to the radius of the cushioning member 14 with respect to the passing locus L of the front contact surface 11h, and when the blade drive arm 11 advances ( When the front contact surface 11h comes into contact during the clockwise rotation), the cushioning member 14 rotates counterclockwise, and when the blade drive arm 11 returns (when counterclockwise swings), the front contact is stopped. The relative position of the cushioning member 14 with respect to the passage of the front contact surface 11h is determined so that the cushioning member 14 rotates clockwise when the contact surface 11h contacts. Further, as a feature of the present invention, the final contact surface 11g before the counterclockwise rotation of the buffer member 14 caused by the contact of the front contact surface 11h with the buffer member 14 during the advance of the blade drive arm 11 is stopped. Contact the cushioning member 14 and the cushioning member 1
Cushioning member against the final contact surface 11g so that the rotation of 4 stops
Fourteen relative positions have been determined. Next, the operation of this embodiment will be described with reference to the above matters. First, in the initial state, the shutter mechanism is in the state shown in FIG. 1. In this state, when a front curtain release signal is applied from a control unit (not shown), an actuator (not shown) operates to move the blade drive arm 11 to the shaft 10a. Is oscillated in a clockwise direction about the center, and the oscillating motion of the blade drive arm 11 is stopped at the position where the final contact surface 11g of the blade drive arm contacts the buffer member 14. At this time, the blade drive arm 12 also swings following the blade drive arm 11, and the blades 13a, 13b, 13c, 13d, and 13e move in parallel downward to open the aperture 10d. (State shown in FIG. 2) Now, when the blade drive arm 11 advances, the final contact surface 11
A state in which the front contact surface 11h of the blade drive arm 11 contacts the buffer member 14 and the front contact surface 11h starts contact with the buffer member 14 in the process of g contacting the buffer member 14 (shown in FIG. 3). From the (state) to the state (the state shown in FIG. 4) in which the front-stage contact surface 11h has finished contacting the cushioning member 14, the front-stage contact surface 11h and the cushioning member 14 are in contact with each other. The buffer member 14 is rotated counterclockwise by the movement of the contact surface 11h. The counterclockwise rotation of the cushioning member 14 is maintained by the inertial force even after the front contact surface 11h is separated from the cushioning member 14, and before the rotation is naturally stopped, as shown in FIG.
11g comes into contact with the buffer member 14 and the rotation of the buffer member 14 stops. At this time, needless to say, the shock generated by the impingement of the blade drive arm 11 on the buffer member 14 is absorbed by the buffer member 14, and the state in which the blade drive arm 11 is stopped at the advance end is shown in FIG. The state shown is as described above. Now, in the return operation after the exposure operation is completed in the state shown in FIG. 2, the blade drive arm 11 is oscillated counterclockwise about the shaft 11a by a mechanism not shown in the figure, and finally, in FIG. Return to the initial state shown in. Referring to the blade drive arm 11 and the buffer member 14, the blade drive arm 11 and the buffer member 14 are in the state shown in FIG. 5 at the start of the return operation, and the blade drive arm 11 has a trajectory opposite to that at the advance. Return to the initial position with. When the blade drive arm 11 swings counterclockwise from the state shown in FIG. 5, the final contact surface 11g separates from the buffer member 14 and then the front contact surface 11h contacts the buffer member, and the front contact surface 11h.
When the front contact surface 11h has stopped contacting the buffer member 14 (state shown in FIG. 4) to the front contact surface 11h (state shown in FIG. 3), 11
h and the cushioning member 14 are in contact with each other.
The movement of 1 h gives the cushioning member 14 a clockwise rotation. The clockwise rotation of the buffer member 14 is maintained by the inertial force even after the front contact surface 11h is separated from the buffer member 14. Then, when the blade drive arm 11 returns, there is no element that forcibly stops the rotation of the cushioning member 14 unlike the advance, so that the cushioning member 14 is automatically stopped by the frictional resistance with the rotating shaft 10e. It will continue to rotate around. As described above, in the present invention, the cushioning member 14 is provided at the time of advancement and return of the blade drive arm 11 which is an example of a movable member.
The amount of rotation of the circular cushioning member 14 is different, and the amount of rotation during each operation varies depending on the camera posture, etc., so that the entire circumference of the circular buffer member 14 is used evenly during long-time use. If the kinetic energy of the drive arm 11 and the material of the buffer member 14 are considered to be common, the durability of the buffer member 14 will be greatly improved. In the above description, the blade drive arm of the focal plane shutter is described as an example of the movable member, but the present invention can be widely applied as long as it is a buffer member of the movable member that passes the same trajectory during advance and return. Of course, the operation locus is not limited to the arcuate shape as described above, and can be applied to, for example, a case of reciprocating linearly.

【effect】

As described above, according to the present invention, as a result of the amount of rotation of the cushioning member being different between the advance stroke and the return stroke of the movable member, the entire circumference of the circular cushioning member is evenly used for impact cushioning. Therefore, when the conditions such as the kinetic energy of the movable member and the material of the cushioning member are made common, the durability of the cushioning member is significantly improved as compared with the conventional one, and especially in recent years. It is possible to sufficiently deal with a case where a high traveling speed is strongly required such as the focal plane shutter. Moreover, since the permanent deformation and wear of the cushioning member are small, the stopping accuracy of the movable member is improved, and a larger obstacle such as the movable member such as a blade overruns the stop position and collides with the camera body. The risk of doing so also decreases. Further, according to the present invention, since the front contact surface and the final contact surface are formed on the side edges of the thin plate-shaped movable member and are not offset from the operation line of the movable member at all, the front contact surface and the final contact surface are not formed. When the contact surface comes into contact with the buffer member, no force is applied to the movable member in the direction of twisting the buffer member, so that the operation of the movable member does not become unstable when the movable member is stopped. Further, in the case of the present invention, since there are no protrusions on the left and right of the moving line of the movable member, it is not necessary to secure a passage path for these protrusions, and the inertia of the entire movable member depends on the mass of these protrusions. There is no increase in weight.

[Brief description of drawings]

FIG. 1 is a front view showing an initial setting state of a focal plane shutter according to one embodiment of the present invention, FIG. 2 is a front view showing an opening state of the focal plane shutter shown in FIG. 1, and FIGS. 5 and 5 are enlarged front views of the blade drive arm and the cushioning member in the focal plane shutter mechanism shown in FIGS. 1 and 2, and FIG. 6 shows the blades in the conventional focal plane shutter mechanism. The front view which expanded and showed the part of a drive arm and a buffer member. 11 ... Blade drive arm, 11g ... Final contact surface 11h ... Previous contact surface, 14 ... Buffer member 10e ... Shaft

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Akira Suzuki 2-16-20 Shimura, Itabashi-ku, Tokyo Copal Co., Ltd. (72) Toshihisa Saito 2-16-20 Shimura, Itabashi-ku, Tokyo Copal Co., Ltd. (56) References Actual Open Sho 56-88227 (JP, U) Actual Open Sho 54-47442 (JP, U) Actual Open Sho 54-10737 (JP, U)

Claims (1)

[Scope of utility model registration request] 1. A reciprocating thin plate-shaped movable member is provided with an elastic cushioning member at an end point in one direction of movement, and a shock generated when a side edge of the movable member finally collides with the cushioning member. In a shock absorbing mechanism that absorbs by elastic deformation of the cushioning member, the outer peripheral surface of the cushioning member is formed in a circular shape, and the cushioning member is rotatably supported with a circular center of the outer peripheral surface as a rotation axis, At the side edge of the movable member, a final contact surface that finally collides with the cushioning member at the operation end point, and a final contact surface that contacts the outer peripheral surface of the cushioning member before colliding with the cushioning member. A front contact surface that applies a rotational force to the buffer member and contacts the outer peripheral surface of the buffer member even in the process of returning the movable member to apply a rotational force in the opposite direction to the buffer member. The contact surface contacts the cushioning member Of the front contact surface and the final contact surface so that the final contact surface contacts the buffer member and stops the rotation of the buffer member before the rotation of the buffer member naturally stops. A shock absorbing mechanism characterized by associating positions.