JPH0447700Y2 - - Google Patents

Description

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

In the conventional focal plane shutter time control mechanism, it is difficult to control the shutter speed at high speeds when electric control is used, and it is possible to control the shutter speed within the normal range even when the battery is exhausted. Because it is necessary to reduce battery consumption, some shutter speeds are mechanically controlled from high to medium speeds using a delay governor, and the low speed side is electrically controlled using an electric timer circuit. However, in the case of such a time control mechanism, there is a position where the cam surface of the speed change cam, which is directly connected to the speed change dial, has the steepest slope in the area where mechanical control and electrical control switch. When this happens, the cam surface does not slide smoothly against the end surface of the lever that contacts the cam surface at that position, causing the speed change dial to become stuck. Therefore, in order to prevent this, if the cam surface of the speed change cam and the end surface of the lever that contacts the cam surface are polished to reduce the roughness, the manufacturing cost increases accordingly. It was hot.

In view of the above-mentioned problems, the present invention aims to provide a seconds control mechanism that can prevent the speed change dial from getting stuck when switching between mechanical control and electric control without increasing manufacturing costs. It is.

The second time control mechanism according to the present invention has two cam surfaces of the speed change cam that correspond to the switching stage between mechanical control and electric control, which are in contact with the speed change lever and the high speed change lever, respectively, from the regular cam surface. By modifying the cam surface so that it is formed gently and the difference in height between the two cam surfaces is small, the fan-shaped gear and roller move into the movement locus of the control cam during electrical control, and the cam surface of the speed change cam is can slide smoothly on the lever end surface that comes into contact with the cam surface.

Hereinafter, the present invention will be explained in detail based on one embodiment shown in the drawings.The first, A speed change cam 6 is formed by integrally forming the second, third and fourth cams 2, 3, 4 and 5 on the top and bottom, and is disposed close to the lower end surface of the speed change cam, as shown in FIG. A guide plate 7 having guide grooves 6a, 6b, 6c, and 6d for respectively guiding the upper end of each switching lever, which will be described later.
is a leading blade drive which is pivotally connected to a substrate (not shown) by a shaft 8, is given right-handed rotation by a spring 9, and has an engaging portion 7a and a pin 7b (not shown) at the tip for driving the leading blade. The lever 10 is pivotally connected to a substrate (not shown) by a shaft 11 and is supported by a spring 1.
2, the bending part 10a is given a dextrorotary behavior and can be engaged with the engaging part 7a and can come into contact with a restraining edge 10' provided on a substrate (not shown), electric time control and maximum speed time control. A leading blade locking lever 13, which has a bending part 10b used for this purpose and an arm part 10c used for other high-speed time control, is pivotally connected to a substrate (not shown) by a shaft 14, and is rotated by a spring 15. A high-speed switching lever 16 has an upper end portion 13a (FIG. 2) whose neck is guided by a guide groove 6b and whose tip surface abuts the cam surface of the second cam 3, which has a left-handed rotation behavior; A high-speed actuation lever 17 is pivotally attached to the lower end of the lever 13, and the high-speed actuation lever 17 is pivotally attached to the other end of the high-speed actuation lever 16, and its shaft portion contacts the upper edge of the arm portion 10c, and its outer peripheral portion is connected to a substrate (not shown). A roller 19, which is guided by a guide edge 18 provided at the top and moves into and out of the locus of movement of a release cam portion of a control cam, which will be described later, by turning the high-speed switching lever 13 left and right, is pivotally connected to a substrate (not shown) by a shaft 20. In addition, a spring 21 imparts left-handed rotation behavior to the protrusion 19a that can push the bending portion 10b during electric time control and maximum speed time control, and a protrusion 19a that can push the roller 17 during other high speed time control. A control cam 22 has a movable release cam portion 19b and an arcuate cam portion 19c that can push a sector-shaped gear to be described later, and is restrained by a release lever (not shown) when the shutter is set. a fan-shaped gear which is pivotally mounted, has a left-handed rotational behavior by a spring 24, and has a pin 22a at its upper end;
25 is a gear 25a pivotally mounted on a board (not shown)
and an escape wheel 25b.
a is a delay governor (third
), 26 is an upper end portion 26 which is pivotally connected to a substrate (not shown) by a shaft 27, whose neck portion is guided to the guide groove 6a, and whose tip surface abuts the cam surface of the first cam 2.
a (FIG. 2) and a lower end portion 26b that abuts the pin 22a from the left, and its right-left rotation causes the fan-shaped gear 22 to be moved by the arc-shaped cam portion 19 of the control cam 19.
The gear change lever 28, which is moved into and out of the movement locus of c, is pivotally connected to a substrate (not shown) by a shaft 29, and has an upper end whose neck is guided by the guide groove 6c and whose tip surface abuts the cam surface of the third cam 4. Part 28a
An ankle switching lever having (Fig. 2);
Reference numeral 30 denotes an ankle lever (Fig. 3) which is pivotally connected to a base plate (not shown) by a shaft 31, is given left-handed rotation by a spring 32, and has one end connected to the lower end of the pallet switching lever 28, and 33 is an ankle lever. A pin 33a pivotally attached to the other end of the ankle lever 30 and implanted on its lower surface is guided by an ankle steadying groove 34 provided on a base plate (not shown), and the ankle lever 30 is rotated left and right by the ankle switching lever 28. This is an ankle that is engaged with and disengaged from the escape wheel 25b via the escape wheel 25b (Fig. 3). Reference numeral 35 denotes a rear blade which is pivotally connected to a base plate (not shown) by a shaft 36, is given right-handed rotation by a spring 37, and has an engaging portion 35a and a pin 35b (not shown) at its tip for driving the rear blade. The drive lever 38 is pivotally connected to a base plate (not shown) by a shaft 39, and has a bent portion 38a which is given left-handed rotation by a spring 40 and can be engaged with the engaging portion 35a.
A rear blade locking lever 41 having a bent portion 38b that can be engaged with one arm portion of the iron piece lever described later, is pivotally connected to a substrate (not shown) by a shaft 29, and is given left-handed rotation by a spring 42. bent part 38
One arm portion 41a and iron piece 43 that can be engaged with and pushed by b.
An iron piece lever 44 is fixed on a substrate (not shown) and is connected to an electric timer circuit (not shown). An electromagnet 45 is configured to attract the iron piece 43 when the shutter is set and to lose its attraction force when the electrical seconds counting end signal is inputted from the seconds circuit. upper end portion 45a (FIG. 2), which is provided with left-handed rotation by a spring 47, whose neck portion is guided by the guide groove 6d, and whose tip surface abuts the cam surface of the fourth cam 5.
This is a time exposure lever having a hook portion 45b capable of locking the other arm portion 41b of the iron piece lever 41. The cam surface 2a of the first cam 2, which corresponds to the switching area between mechanical control and electrical control, is formed so that it is gentler and has a smaller difference in height than the regular cam surface 2a' (shown by the dashed line). There is. or,
The cam surface 3a of the second cam 3 corresponding to the switching area between mechanical control and electrical control is the regular cam surface 3.
It is formed so that it is gentler and has a smaller height difference than a' (shown by a dashed-dotted line). Also, when the upper end 26a of the speed change lever 26 comes into contact with the highest part of the cam surface of the first cam 2, the fan-shaped gear 22
is retracted to a position where it is not affected by the control cam 19, that is, the delay governor 25 becomes inactive, and the fan-shaped gear 22 begins to be affected by the control cam 19 in accordance with the height of the cam surface of the first cam 2. It is configured such that the position changes, that is, the amount of action of the delay governor 25 changes. Further, when the upper end 13a of the high-speed switching lever 13 comes into contact with the lowest part of the cam surface of the second cam 3, the roller 17 moves toward the control cam 1.
The roller 17 is retracted to a position where it is not affected by the action of the roller 17, and the roller 17 is moved in accordance with the change in the height of the cam surface of the second cam 3.
The structure is such that the position at which the leading blade begins to receive the action of the control cam 19, that is, the starting position of the leading blade changes. In addition, in the case of mechanical control, the electric seconds circuit is
It is configured to emit a seconds count signal in synchronization with the maximum speed seconds.

Since the seconds control mechanism according to the present invention is constructed as described above, the speed change cam 1 can be rotated to, for example,
When set to the mechanical control position for 15 seconds, the upper end 26a of the gear change lever 26 comes into contact with the lowest part of the cam surface of the first cam 2, so it rotates to the right by the maximum angle and the lower end 26b turns to the right. move to the left,
As a result, the fan-shaped gear 22 rotates to the left and enters the deepest position within the motion locus of the arcuate cam portion 19c of the control cam 19. Also, the high-speed switching lever 13 comes into contact with the highest part of the cam surface of the second cam 3, so that the high-speed switching lever 13 rotates to the right by the maximum angle, and as a result, the roller 17 is rotated to the left via the high-speed operation lever 16. The release cam portion 19 of the control cam 19 is moved diagonally upward.
It penetrates the deepest into the locus of motion. Therefore, the leading blade locking lever 10 is in a state where it can be rotated to the left via the roller 17 at the earliest possible time.
Further, the ankle switching lever 28 has its upper end 28
Since a comes into contact with the lower part of the cam surface of the third cam 4, it rotates to the right, and as a result, the ankle lever 3
0 rotates to the left and the pallet wheel 33 comes to engage the delay governor 25. Also, since the upper end 45a of the time exposure lever 45 is in contact with the high part of the cam surface of the fourth cam 5, the hook portion 45b locks the other arm portion 41b of the iron piece lever 41 as shown in FIG. As a result, the time exposure mechanism is no longer working.

Here, when the shutter release is performed, the control cam 19 starts to rotate counterclockwise, and the release cam portion 19b first pushes the roller 17 to rotate the leading blade locking lever 10 to the left, thereby locking the leading blade drive lever 7. Release the button and start the leading blade. Next, the arcuate cam part 1
9c pushes the fan-shaped gear 22, the delay governor 25 acts, and after the arc-shaped cam part 19c is disengaged from the sector-shaped gear 22, the roller 41c falls into the lower part of the circumferential surface of the arc-shaped cam part 19c (when the set time elapses) time) The iron piece lever 41 rotates to the left. Therefore, the trailing blade locking lever 38 is turned to the right, the locking of the trailing blade drive lever 35 is released, and the trailing blade starts.

Next, a case will be described in which the speed change cam 1 is rotated and set to the 1/8 second electric control position. First, if the first cam 2 and the second cam 3 are of a regular cam shape (shown by the dashed line in FIG. Since it comes into contact with the highest part, it rotates to the left by the maximum angle and the lower end portion 26b moves to the right, and as a result, the fan-shaped gear 22 is rotated to the left and retreats out of the motion trajectory of the arc-shaped cam portion 19c of the control cam 19. do. Therefore, the delay governor 25 has no effect. In addition, the high-speed switching lever 13 comes into contact with the lowest part of the cam surface of the second cam 3, so that the high-speed switching lever 13 rotates to the left by the maximum angle, and as a result, the roller 17 is rotated diagonally to the right via the high-speed operation lever 16. The release cam portion 19b of the control cam 19 is moved downward and retreated out of the movement trajectory. Therefore, the leading blade locking lever 10 can be directly pressed and rotated by the protrusion 19a of the control cam 19.
Further, the ankle switching lever 28 has its upper end 28
Since a comes into contact with the high part of the cam surface of the third cam 4, it rotates to the left, and as a result, the ankle lever 3
0 rotates to the right and the pallet wheel 33 comes off the delay governor 25. Also, since the time exposure lever 45 is in the same state as the 1/15 second mechanical control, the time exposure mechanism does not work.

When the shutter is released, the control cam 19 starts rotating to the left, and a trigger switch of an electric seconds circuit (not shown) is turned off to start counting electric seconds. Subsequently, the protrusion 19a directly pushes and rotates the leading blade locking lever 10 to the left, and starts the leading blade in the same manner as in mechanical time control. Next, set the time in seconds (1/8 seconds) from the trigger switch OFF.
After the elapse of time, the electromagnet 44 is turned off by the counting end signal and loses its adsorption force, and as a result, the iron piece lever 41 starts turning left and the rear blade locking lever 38 turns right. Therefore, the trailing blade starts in the same way as in mechanical time control. The movements of the control cam 19 and the iron piece lever 41 in the above case are shown in curves a' and b in FIG. 4, respectively. And the time from trigger switch OFF to leading blade start t ₁
Since the structure is configured so that the time t ₂ from the loss of the attraction force of the electromagnet 44 to the start of the trailing blade is equal, the shutter opening time is the set second (1/8 second).
become a street.

On the other hand, if the first cam 2 has a cam shape according to the present invention (the cam surface has a gentle inclination and a small height difference as shown by the solid line in FIG. 2), the shift change lever 26 Since it comes into contact with a lower part than in the normal case, it rotates to the right and the lower end part 26b returns to the left, so that the fan-shaped gear 22 enters the motion locus of the arc-shaped cam part 19c of the control cam 19. become. Therefore, when the shutter is released, the control cam 19 pushes the fan-shaped gear 22 after turning off the trigger switch, that is, it is subjected to a certain action of the delay governor 25. Therefore, the movement of the control cam 19 slows down as shown by curve a in FIG. 4, and if this continues, the timing of starting the leading blade will be delayed. However, in the case of the present invention, the cam shape of the second cam 3 is
As shown by the broken line in the figure, the cam surface is configured to have a gentle inclination and a small height difference, and since the high-speed switching lever 13 comes into contact with a higher part than in the normal case, it rotates to the right and reaches the lower end. portion returns to the left, and as a result, the roller 17 enters into the locus of movement of the release cam portion 19b of the control cam 19. Therefore, as shown in Fig. 4, the leading blade start position is advanced compared to the normal case, so the time from the trigger switch OFF to the leading blade start can be made almost equal to the time _t1 in the normal case. As a result, the shutter opening time will almost match the set time (1/8 second).

The operating principle of the second time control mechanism according to the present invention has been explained above.The second time control mechanism according to the present invention is based on the first cam 2 of the cam surface of the speed change cam 1 corresponding to the switching stage between mechanical control and electric control. and second cam 3
The cam surfaces 2a and 3a are the regular cam surfaces 2a' and 3.
Since the cam surfaces 2a and 3a are formed more gently than a', both cam surfaces 2a and 3a can slide smoothly on the respective end surfaces of the speed change lever 26 and the high speed change lever 13, respectively, without the need for polishing. . Therefore, it is possible to reliably prevent the speed change dial from getting stuck when switching between mechanical control and electric control without increasing manufacturing costs. Further, since the heights of both cam surfaces 2a and 3a are corrected in a direction that complements each other, the shutter open time can be maintained at the regular set seconds as described above.

In addition, as shutter speeds have recently become faster and more multi-functional, the number of switching stages on the speed dial has increased, and the switching angle for each stage is extremely limited, resulting in a very steep slope of the cam surface of the speed change cam that is directly connected to the speed change dial. If the axis of the gear shift cam and the axis of the shift lever are perpendicular to each other, the shift lever tends to tilt when changing the gear dial, causing the gear dial to become stuck, and the speed change at each second is more likely to occur. Since the stable area (flat area) of the corresponding shift cam is also limited, if there is play in the switching lever, the switching lever may move out of the stable area onto the slope, causing the problem of unstable shutter speed. Ta. However, in the second time control mechanism according to the present invention, as described above, each guide groove 6a, 6b, and 6
Since the gears are guided by the gears c and 6d, tilting and rattling of each switching lever are prevented, and as a result, the gear shift dial is prevented from getting stuck, and the shutter speed is also stabilized.

As mentioned above, the second time control mechanism according to the present invention can reliably prevent the speed change dial from getting stuck when switching between mechanical control and electric control without increasing manufacturing costs, and can also reduce the shutter opening time. It has an important practical advantage of being able to maintain the regular setting time.

[Brief explanation of the drawing]

FIG. 1 is a front view of an embodiment of the seconds control mechanism according to the present invention, FIG. 2 is a plan view of the speed change cam of the above embodiment, FIG. 3 is a front view of the area around the delay governor of the above embodiment, and FIG. The figure is a graph showing the movement of the control cam and iron lever. 1... Speed change cam, 6... Guide plate, 7... Leading blade drive lever, 10... Leading blade locking lever, 1
3...High speed switching lever, 16...High speed operation lever, 17...Roller, 19...Control cam, 22...
... Sector gear, 25 ... Delay governor, 26 ... Speed change lever, 28 ... Ankle change lever, 30 ... Ankle lever, 33 ... Ankle, 35 ... Rear blade drive lever, 38 ... Rear blade locking Lever, 40... Iron piece lever, 44... Electromagnet, 45... Time exposure lever.

Claims (1)

[Scope of utility model registration request] a leading blade driving member, a leading blade locking member capable of locking the leading blade driving member in a tensioned position, a trailing blade driving member, and a trailing blade locking member capable of locking the trailing blade driving member in a tensioned position; A control cam that can sequentially operate the leading blade locking member and the trailing blade driving member by shutter release and release the leading blade driving member and the trailing blade driving member in sequence, and a control cam that can engage with the control cam and delays the movement of the control cam. an electromagnet connected to an electric timing circuit; and an iron piece lever that can come into contact with the rear blade locking member and the control cam and that can actuate the rear blade locking member when released by the electromagnet. a speed change cam having a first cam and a second cam; a speed change switching member having one end in contact with the first cam and the other end in contact with a fan-shaped gear connected to a delay governor; and one end in contact with the second cam. and a high-speed switching member whose other end abuts the leading blade locking member and supports a roller member that can abut the control cam, and when the speed-changing cam is set in a range from high speed to medium speed. Depending on the set time, the roller member is brought to any position within the motion trajectory of the control cam via the high-speed switching member, and the sector gear is brought to any position within the motion trajectory of the control cam via the speed change switching member. When the set speed is mechanically controlled and the speed change cam is set in the low speed range, the roller member and sector gear are controlled via the high speed switching member and the speed change switching member. A focal plane shirt is brought out of the cam's motion orbit, and the adsorption time of the iron piece lever by an electromagnet is determined by an electric time circuit according to the set time, so that the set time is electrically controlled. In the second time control mechanism of the
In order to switch from mechanical control to electrical control, the cam surfaces of the first cam and second cam are formed with gentle slopes, and the steps of each cam are formed to be small, so that even during electrical control, the fan-shaped cam surface is formed. A second time control mechanism characterized in that a gear and a roller member advance into the motion trajectory of a control cam.