JPH0447701Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a time control mechanism for a focal plane shutter.

The time control mechanism of conventional mechanically controlled focal plane shutters uses an intermediate member that changes the position at which the cam part of the control cam starts acting on the control cam by changing the set time. It was configured to push the locking member in the unlocking direction, but for example, when the highest speed per second (1/4000 seconds) is set, the amount of pushing by the control cam of the leading blade locking member becomes too small. There was a problem in that the leading blade was not unlocked when the blade was turned. However, in order to solve this problem, if the amount of pushing by the control cam of the leading blade locking member at the highest speed is increased, the speed at other high speeds (1/500 seconds), which is relatively slow, will be increased.
In this case, there was a problem in that the amount of pushing of the leading blade locking member by the control cam became too large than necessary, and the control cam had to perform unnecessary work correspondingly. Furthermore, an increase in the amount of movement of each member is not desirable in terms of space for a camera that is required to be compact.

In view of the above-mentioned problems, the present invention aims to provide a time control mechanism that can reliably release the leading blade at the maximum speed per second without increasing the amount of operation of each member. .

The time control mechanism according to the present invention has a protrusion that directly pushes the leading blade locking member on the control cam for maximum time control, independently of the cam part, and rather than the cam part pushing the intermediate member. The leading blade locking member is provided at a position where it is pushed at a late stage, and the intermediate member is retracted out of the movement trajectory of the cam section during maximum speed control, so that the control cam of the leading blade locking member at that time This ensures a sufficient amount of pushing movement.

Hereinafter, the present invention will be explained in detail based on the illustrated embodiment. FIG. 1 shows the set state at the time of maximum speed control.
A leading blade drive lever 4 is pivotally connected to the (see figure), is given right-handed rotation by a spring 3, and is provided with an engaging portion 1a and a pin 1b (not shown) for driving the leading blade at its tip. As shown in FIG. 2, one end of the hole 5 is pivotally attached to the board A with some play, and the other end has a clearance in the direction perpendicular to the plane of the paper of the board B.
A support shaft 6 fitted into the support shaft 4 is pivotally connected to the support shaft 4, and is given a right-handed rotation by a spring 7, so that it can engage with the engaging portion 1a and engage with the restraining edge 8 provided on the base plate A. a leading blade locking lever having a bending part 6a that can be brought into contact, a bending part 6b used for maximum speed timing control, and an arm part 6c used for other high speed timing control;
Reference numeral 9 denotes an adjusting plate whose upper end is pivotally connected to the substrate B by a shaft 10, whose central part is fitted to one end of the support shaft 4, and whose lower end is formed with an oval hole 9a (see Fig. 2). , 11 is an adjustment screw which is pivotally attached to the board B and whose width center shaft portion 11a is fitted into the oval hole 9a, and 12 is an adjustment screw whose one end has a slight play in the board B as shown in FIG. A spindle 1 that is held and pivotally connected, the other end is pivotally connected to a substrate C, and an eccentric shaft portion 12a and a two-way chamfered portion 12b are provided in the middle.
3 is pivotally connected to the eccentric shaft portion 12a of the support shaft 12, and is given left-handed rotation by a spring 14, and the upper end portion 1
3a is a high-speed switching lever that is in contact with a cam surface 15 of a speed change cam (not shown), 16 is a high-speed operating lever whose one end is pivoted to the lower end of the high-speed switching lever 13, and 17 is the other end of the high-speed operating lever 16. The shaft portion is in contact with the upper edge of the arm portion 6c, and the outer peripheral portion is guided by a guide edge 18 provided on the board C. By turning the high-speed switching lever 13 left and right, the control cam, which will be described later, is rotated. A roller 19 moves into and out of the movement locus of the release cam portion, and a shaft 20 moves the roller 19 to the substrate C.
A protrusion 19a is pivotally attached to the holder and is given left-handed rotation by a spring 21, and can push the bending part 6b during maximum speed time control, and a protrusion 19a that can push the roller 17 during other high speed time control. This control cam has a release cam portion 19b that can be used to release the shutter, and an arcuate cam portion 19c that is subjected to the action of a delay governor (not shown) during high-speed time control. is the control cam 19
The release cam portion 19b is provided at a position to push the bending portion 6b at a later stage than the roller 17 is pushed when the release cam portion 19b is activated. Reference numeral 22 denotes a rear blade drive which is pivotally connected to the substrate A by a shaft 23, is given right-handed rotation by a spring 24, and has an engaging portion 22a at its tip and a pin 22b (not shown) for driving the rear blade. The lever 25 is pivotally connected to the base plate B by a shaft 26, and is given left-handed rotation by a spring 27, and has a bent portion 25a that can be engaged with an engaging portion 22a and an arm portion of a trailing blade actuating lever, which will be described later. Bending portion 2 that can be matched
2b, the rear blade locking lever 28 is an arm that is pivotally connected to the base plate C by a shaft 29, is given left-handed rotation by a spring 30, and can be pushed by engaging with the bent portion 25b. 28a and a roller 28b that slides on the circumferential surface of the arcuate cam portion 19c of the control cam 19. Note that when the upper end 13a of the high-speed switching lever 13 comes into contact with the lowest part of the cam surface 15, the roller 17 moves toward the control cam 19.
At the same time, the position where the roller 17 starts to receive the action of the release cam part 19b, that is, the starting position of the leading blade, changes according to the change in the height of the cam surface 15. It is composed of

Since the seconds control mechanism according to the present invention is constructed as described above, when the speed change cam is rotated and set to the highest speed seconds position, the high speed switching lever 13
Since its upper end 13a comes into contact with the lowest part of the cam surface 15, it rotates to the left by the maximum angle, and as a result, the roller 17 moves diagonally downward to the right via the high-speed operation lever 16, as shown in FIG. The release cam portion 19b of the control cam 19 is forced to move out of the movement trajectory. Therefore, the leading blade locking lever 6 can be directly pressed and rotated by the protrusion 19a of the control cam 19. Further, in this case, the arcuate cam portion 19c of the control cam 19 is not affected by the delay governor.

Here, when the shutter release is performed, the control cam 19 rotates to the left, and as shown in FIG. The leading blade drive lever 1 is unlocked to start the leading blade. Subsequently, the control cam 19 continues to rotate while the arcuate cam portion 19c is not affected by the delay governor, and the roller 28b
falls into the lower part of the circumferential surface of the arcuate cam portion 19c (at the time when the set time has elapsed), and the rear blade locking lever 28 rotates to the left. Therefore, the trailing blade locking lever 25 is turned to the right, the locking of the trailing blade drive lever 22 is released, and the trailing blade starts.

Next, when the speed change cam is rotated and set to another high speed position, the high speed change lever 13 rotates to the right as its upper end 13a comes into contact with the high part of the cam surface 15. As a result, as shown in FIG. 5, the roller 17 is moved diagonally upward to the left via the high-speed actuation lever 16, and the release cam portion 1 of the control cam 19 is moved.
It comes into the motion trajectory of 9b. Therefore, the leading blade locking lever 6 is in a state where it can be rotated to the left via the roller 17. Also, in this case, the arcuate cam portion 19c of the control cam 19 is acted upon by a delay governor.

Here, when the shutter release is performed, the control cam 19 rotates to the left, and as shown in FIG. Release the lock of the drive lever 1 and start the leading blade. continue,
The arcuate cam portion 19c continues to rotate under the action of the delay governor, and the roller 28b moves toward the arcuate cam portion 1.
The trailing blade actuating lever 28 is turned to the left when the trailing blade falls to a low part of the circumferential surface of the blade 9c (at the time when the set time has elapsed), and the trailing blade locking lever 25 is turned to the right in the same manner as described above to start the trailing blade.

The operating principle of the time control mechanism according to the present invention has been explained above.The time control mechanism according to the present invention has a protrusion 19a on the control cam 19 that directly pushes the leading blade locking member 6 in order to control the maximum time. It is provided at a position where the leading blade locking member 6 is pushed independently of the release cam part 19b and at a later stage than the release cam part 19b pushes the roller 17, and the intermediate member (roller 17) is retracted out of the movement trajectory of the release cam portion 19b, so the amount of pushing by the control cam of the leading blade locking lever is set for the maximum speed seconds control, regardless of other high speed seconds control. Moreover, since the speed of the control cam increases from the point at which the intermediate member is pushed by the control cam, and the operating angle can be increased, a sufficient amount of pushing can be ensured. Therefore, the leading blade can be reliably unlocked at the highest speed without increasing the amount of operation of each member.

As described above, the timing control mechanism according to the present invention has the practically important advantage of being able to reliably release the locking of the leading blade at the highest speed timing without increasing the amount of operation of each member.

[Brief explanation of the drawing]

FIG. 1 is a front view showing the set state of an embodiment of the second control mechanism according to the present invention, FIGS. 2A and B are a front view and longitudinal cross-sectional view of the high-speed switching lever and its surroundings in the above embodiment, and FIG. 3 A and B are a front view and a longitudinal cross-sectional view, respectively, of the leading blade locking lever of the above embodiment;
FIG. 4 is a front view showing the highest speed second control state of the above embodiment, and FIG. 5 is a front view showing another high speed second control state of the above embodiment. 1... Lead blade drive lever, 4... Support shaft, 6...
Lead blade locking lever, 9...Adjustment plate, 11...Adjustment screw, 12...Spin shaft, 13...High speed switching lever, 16...High speed operation lever, 17...Roller,
19... Control cam, 22... Rear blade drive lever,
25...Rear blade locking lever, 28...Rear blade operating lever.

Claims (1)

[Scope of utility model registration request] a leading blade locking member, a leading blade locking member capable of locking the leading blade driving member in the tensioned position, a trailing blade driving member, and a trailing blade locking member capable of locking the trailing blade driving member in the tensioned position. , a control cam capable of sequentially operating a leading blade locking member and a trailing blade locking member by a shutter release to sequentially release the leading blade driving member and the trailing blade driving member; and a high-speed switching member displaced by a speed change cam. , an intermediary member that can move forward and backward into the movement trajectory of the control cam by a high-speed switching member and is in contact with the leading blade locking member, and when the shutter is released, the leading blade is locked by the cam portion of the control cam via the intermediate member. In a focal plane shutter time control mechanism in which a member is actuated, when the highest speed is set, an intermediary member is moved out of the control cam's motion trajectory via a high-speed switching member that is displaced by a speed change cam. A second time control mechanism characterized in that a leading blade locking member is provided on a control cam and is directly operated by a protrusion independent of the cam portion.