JPS612139A - Electromagnetic driving shutter - Google Patents

Abstract

PURPOSE:To save the current consumption of an electromagnetic driving shutter and to stabilize the accuracy of the shutter by forming a blade holding means for mechanically holding a shutter blade at a travelling completing position and stopping power supply to an electromagnetic driving source. CONSTITUTION:A front blade driving pin 6 is abutted upon a bending part 36a of a front blade holding spring 36 projected to its rotation course immediately before the travelling completing position, completed at its travelling after getting over the bending part 36a against its elasticity and held by the holding pin 36. Since a front blade travelling completion switch 50 is pressed by the pin 6 and turned on simultaneously, current supply to a driving source coil is stopped. In a back blade driving part, its driving pin 4 is abutted upon its holding spring 34 immediately before the travelling completing position, and after getting over its bending part 34a, held at the travelling completing position by the spring 34 and a back blade travelling completion switch 51 is turned on to interrupt the current supply to the driving source. Thus, the power consumption is saved and the shutter accuracy is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Application) The present invention relates to a mechanism for holding shutter blades in an electromagnetically driven shutter at a position where the shutter blades have completed their travel.

(Prior art) Generally, in an electromagnetically driven shutter, when the shutter blades are traveling for exposure, the blades are driven by an electromagnetic drive source, and when returning to the travel starting position, the blades are driven by a spring. There are many things. With this type of shutter, it is necessary to hold the shutter blade in the travel completion position against a return spring until the exposure is completed. Conventionally, this was done by continuously passing current through an electromagnetic drive source after the shutter blade struck. I was going. In other words, the movable coil of the shutter leading blade continues to be energized until the shutter trailing blade completes its travel, and when the shutter trailing blade completes its travel, both coils are de-energized, and the force of the return spring automatically returns the movable coil to the travel starting position. It is something to return.

However, compared to conventional mechanical shutters, this method requires an electromagnetic drive shutter that consumes much more current, which means that the battery built into the camera must be replaced frequently or replaced with a larger capacity one. I needed to.

Furthermore, the temperature of the moving coil of the shutter leading blade increases because the current is always passed through it in a locked state for a longer period of time than the moving coil of the trailing blade.

Therefore, the temperature-dependent resistance value of the coil increases, and the flowing current decreases.

Since the electromagnetic force that drives the shutter is proportional to the product of the current flowing through the moving coil and the number of turns of the moving coil, the curtain speed of the shutter leading blade gradually decreases.

For this reason, in conventional electromagnetically driven shutters, shutter accuracy deteriorates as the number of releases increases, and this tendency is particularly noticeable when a motor drive is used.

(Summary of the Invention) The present invention aims to solve the above-mentioned conventional drawbacks and to obtain an electromagnetic drive shutter that consumes less current and provides stable shutter accuracy, and aims to provide an electromagnetic drive shutter that can reduce current consumption and provide stable shutter accuracy. All stages of the shutter blade holding members are placed at the end of the path, and the shutter blades are mechanically held at the position where the shutter blades have completely traveled.

(Example〕 Embodiments of the present invention will be described below with reference to the drawings.

Fig. 1 is a perspective view showing the basic structure of an electromagnetically driven focal plane shutter to which the present invention is applied, in which 1a is a slit forming blade of the rear blade, 1b to 1e are auxiliary blades, and the main plate is as shown in Fig. 2. They are attached to arms 2 and 3 that are rotatable around shafts 8 and 9, respectively, to form parallel links using connecting pins 2a to 2e, 3a to 3e, and the rear blades are folded at the running start position shown in the figure. It is folded and stored on one side of the opening. 1'1 is the slit forming blade of the leading blade, 1'b
~1' is an auxiliary blade, which is connected to arms 2' and 3' that can rotate around shafts 10 and 110 in the same way as the rear blade.
r, 3r &~3'6 are attached to form a parallel link, and the leading blade covers the opening before the start of travel. 12 is an electromagnetic drive source for the rear blade attached to the main plate via a mounting member (not shown); 20 is a permanent magnet;
6 is a yoke, 23 is a movable coil that rotates within the magnetic field of a permanent magnet, and 14 is a rear blade drive shaft fixed to the coil, which is provided concentrically with the shaft 5 of the arm 3. 18 is a commutator for the coil 23, and 19 is a power feeding brush.

A rear blade drive lever 5 is fixed to the lower end of the rear blade drive shaft 14, and a pin 4 planted on the lower surface of the lever 5 fits into a hole provided in the lever 3 to transmit rotation of the coil 23 to the lever 3. It has become.

13 is an electromagnetic drive source for the leading blade, and an electromagnetic drive source 12 for the trailing blade.
The drive shaft 15 is connected to the leading blade arm 2' via a leading blade drive lever 7 and a pin 6.

FIG. 2 shows an embodiment of the present invention, in which the leading and trailing blades of the shutter are held between the base plate 38 and the cover plate 39, and the clockwise rotation of the coil 23 of the electromagnetic drive source is caused by the base plate 38. A circular arc groove 38b is provided.

As described above, the driving pins 38ai are transmitted to the arms 2' and 3 through the drive beams 6 and 4t, respectively, so that they travel in the directions of the arrows to open and close the opening 38ai.

Reference numeral 32 denotes a leading blade protrusion prevention lever which is pivotally supported by a shaft 33 on the base plate and rotated counterclockwise by a spring 47, and when the leading blade is at the travel start position, the tip 32 m is used to drive the leading blade. It faces one arm 7b of the lever 7 to prevent its rotation, thereby preventing the opening from opening due to movement of the slit forming blade.

Reference numeral 31 denotes a rear blade protrusion prevention lever which is pivotally supported on the same shaft 33 and rotated counterclockwise by a spring 46, and the tip 31m engages with one arm 5b of the rear blade drive lever 5 in the same way as 7 above. This also prevents the rear curtain from rotating and prevents the rear curtain from jumping out due to the internal pressure of the opening.

Reference numeral 30 denotes an actuating lever that is pivotally supported on a shaft 42 and acts on the blocking lever, and the - arm is provided with a bent portion 30m that engages with the narrow arms 32b and 31b of the blocking levers 32 and 31, and the other end is A bin 30b is fixedly attached to the bin 30b.

Reference numeral 24 is a galvanized stone fixed to the main plate via a mounting member 25, and when the coil 26 is energized, it attracts the armature 27 and rotates it around the shaft 25a.
7 a to press the pin 30 b i to release the actuating lever 30.
It is designed to rotate counterclockwise.

28 is a charge lever for pushing the leading blade drive lever and the trailing blade drive lever back towards the travel start position in conjunction with film winding, and its elongated hole fits into @29 and 42 and is slidably guided in the longitudinal direction. There is.

48 is a winding interlocking shaft that is linked to a winding mechanism (not shown) and rotates once every time a film frame is rolled up, and is a disc 48 a provided at the lower end.
The bottle 48 b i is fixedly planted at an eccentric position. Reference numeral 40 denotes a return lever that is pivotally supported on the main plate 49 by a shaft 49a, and the bent portion 40a at the upper end abuts on the aforementioned bottle 48h, and rotates around the shaft 4011 in accordance with the rotation of the shaft 48. By doing so, the lower end 40b (as shown in Figure 3) of the charge lever 28't is moved to the right in the figure.

44 and 45 are leading blade drive members 7. a return spring for rotating and biasing the drive lever 5 toward the travel start position on the rear wing;
Reference numerals 36 and 34 indicate retaining springs that hold the drive bins 6 and 4 at the travel completion positions, respectively, and their bases are fixed to the main plate 38 with studs 35 and 37, and the locking bent portions 36a and 34a at the ends are the drive springs. It protrudes near the end of the rotation path of the bins 6 and 4.

50 is a leading blade travel completion switch that is turned on by being pushed by the leading blade drive pin 6, and 51 is a trailing blade travel completion switch that is turned on by the leading blade drive pin 4.

Next, the operation of the shutter will be explained. As shown in FIG. 1, the current-carrying brush 19. When a current is applied to the leading blade drive coil 23 via the commi-data 18, a magnetomotive force known as the 6 Fleming's left-hand rule is generated in the coil, and the drive shaft 1
A rotational force is generated at 5. This rotation is caused by the leading blade drive lever 7,
Via the drive pin 6, the vane drive arm 2 is rotated about the axis 11.

As mentioned above, arms 2' and 3' and shutters 1'a to 1
'e has the entire parallel link mechanism, so arm 2'
As the blades rotate, the amount of overlap between each blade increases from left to right in the figure, and the blades move in parallel to open the aperture and begin exposure. Subsequently, when power is applied to the rear blade drive coil 23 in the same manner, the rear blade drive shaft 14 rotates, and the rear blades 18 to 1e gradually open from the mutually overlapping state shown in the figure and move to the right in Figure 3 to open. The exposure is completed when the area is completely covered.

When the preparation for the exposure run as described above is completed and the leading blade and trailing blade are in the running standby state as shown in the first figure, the leading blade drive pin 6
receives the force of the return spring 440 and hits a stopper (not shown), causing the drive lever 7 to stop.The leading blade protrusion prevention lever 32 receives the biasing force of the spring 47 and bends the release lever 30 at its left end. Press the part 30ai, and press the other lever 30J) f
il bottle 3gb by boot 1 chale lever arm 27a
i It is stopped in the pushed up position. At this time, the blocking lever 3
As shown in FIGS. 2 and 3, the tip 32a of the drive lever 7 faces the arm 7b of the lever 7 that moves toward the leading blade P1 with a small distance therebetween, and prevents the entire rotation of the drive lever 7 in the running direction. prevent,
Prevents shutter blades from flying out. Similarly, the rear blade protrusion prevention lever 31 receives the force of the spring 46 and moves to the left end 31.
b is stopped in a state where it is engaged with the operating lever 3o, and its tip 31a faces the arm 5b of the rear blade drive lever 5 with a slight distance therebetween.

Next, when a release operation is performed, the coil 26 of the electromagnet 24 is first energized, and the armature 27 is attracted by the yoke and rotates around the circumference 9 of the shaft 25 m in the direction J1. As a result, the other line 27a pushes the bottle 30b and rotates the operating lever 30 around the metal shaft 420 in the counterclockwise FN'' direction.
As shown in the figure, the bent portion 30a at the right end of the lever 30 is connected to the leading blade protrusion prevention lever 32 and the trailing blade protrusion prevention lever 3.
Push up the arm portions 32 b and 31 bi of No. 1 and rotate each lever clockwise against the respective springs 47 and 46 to retract the tip portions 32 a and 31 a from the travel blocking position of each drive lever, The shutter becomes ready to run.

Next, the leading blade drive source 13. Coil 2 of rear blade drive source 12
When power is supplied sequentially with a time lag according to the shutter speed set to 3, the drive lever 7 is activated as described above.
- 5 rotates clockwise, and the arms are fully operated via drive pins 6 and 4, causing the shutter blade to travel. Immediately before the travel completion position, the leading blade drive pin 6 comes into contact with the bent portion 36a of the leading blade holding spring 36 protruding into its rotation path, and resists the elasticity of the spring to rotate the bent portion 36a'i. When it has climbed over, the running distance is completed and it is held by the holding spring 36 as shown in FIG. At the same time, the leading blade running completion switch 50 is pressed by the bottle 6 and turned on, thereby stopping the power supply to the leading blade drive coil 23.

Similarly to the leading blade, the drive pin 4 rests on the holding spring 34 just before the travel completion position, and after bending the spring and overcoming the bending portion 34 m, the rear blade drive lever 5 is held at the travel completion position by the spring. Then, the power to the coil 23 is cut off by turning on the trailing blade travel completion switch.

At the same time, the energization of the electromagnet 24 is also stopped, the armature 27 is separated from the yoke, and the leading blade protrusion prevention lever 32, which had been moved to the travel-enabled position via the operating lever 30, is stopped.
and the rear blade protrusion l ~ hindrance [the fin per 31 has a return spring 47
- 46 returns each drive lever 7, 5 to its rotation blocking position.

When the travel of the shutter trailing blade is completed, film winding begins by known means. FIG. 6 is a diagram showing the state immediately after starting the film winding operation. The hoisting interlocking shaft 48 interlocked with the hoisting mechanism starts rotating, and the rotating plate 48
When the upper surface of the bent portion 40a of the return lever 40 is pushed by the movement of the pin 48b on the top a from the right to the left in the figure, the lever 40 rotates counterclockwise around the shaft 498 and 1i', il' 40h to push the left end of the charge lever 28 and move the charge lever in the direction of the arrow. At this time, the charge lever 28b pushes the pin 5ai on the rear blade drive lever 5.

For this reason, each of the drive levers 7 and 5 receives a rotational force in the counterclockwise direction opposite to the running direction, and the leading blade drive pin 6 and the trailing blade drive pin 4 are forcibly moved to the bent portions 3 of the holding springs 36 and 34.
m, 34 a f The hold at the travel completion position is released. By the subsequent rotation of the return lever 40, the drive levers 7 and 5 are pushed toward the travel start position at high speed, and then returned to the travel start position by the inertial force and the weak force of the return springs 44 and 45. The return lever 40 and the charge lever 28 return to their old positions by the force of a spring (not shown) when the hoisting interlocking shaft 48 makes one rotation and stops.

During this returning movement, the arm 7b of the leading blade drive lever 7 comes into contact with the side surface 32c of the leading blade protrusion prevention lever 32, as shown in FIG.
When the push lever 32 rotates and is disengaged from the lever just before the travel start position, the blocking lever 32 is rotated by the force of the return spring 47 and enters the travel blocking position again, and the drive lever 7 returns. Prevents it from bouncing back due to the recoil of time. [In addition, this reaction is converted into a vibration with a known period due to the minute distance between the two levers mentioned above and is rapidly damped, and the leading blade μ (drive lever 7 becomes stationary).Similarly, the trailing blade drive lever 5 is also prevented from rebounding by the blocking lever 31 and becomes stationary, returning to the shutter running standby state shown in FIG. 3, and the series of shutter operations is completed.

(Effects of the Invention) As described above, the present invention provides a mechanism for mechanically holding the shutter blade at the travel completion position, so there is no need to continue supplying current to the drive coil after travel is complete, as in the conventional case.
It is possible to obtain an electromagnetic drive shutter that can save electric power and provide stable precision without changing the shutter speed due to heat generation as described above.

[Brief explanation of the drawing]

Fig. 1 is a perspective view explaining the operating principle of an electromagnetic drive shutter, Fig. 2 is a perspective view showing an embodiment of the present invention, Figs.
, FIG. 5, FIG. 6, and FIG. 7 are plan views showing the operating state of the mechanism section in each stroke in the same embodiment. 1a-1e: Shasoter rear blade, 1'a-1'e rainbow,
? Twin tip blade, 2, 3, 2', 3': Shutter operating arm, 4: Rear blade drive pin, 5: Rear blade drive lever,
6: Leading blade drive bin, 7: Leading blade driving lever, 12.1
3: Electromagnetic drive source, 24: Electromagnet. 28: Charge lever, 30: Operation lever, 31: Rear blade protrusion prevention lever, 32: Lead blade protrusion prevention 1 lever, 34: Rear blade holding lever, 36: Leading blade holding I/bar, 40: Return lever, 44/45: Return spring.

Claims (1)

[Claims] In a shutter that moves the shutter blade for exposure by energizing the electromagnetic drive source, a holding spring that engages with the shutter drive member is provided at the end position of the shutter drive member, and the electromagnetic drive source simultaneously holds the shutter blade at the completion position of the shutter drive member. An electromagnetic drive shutter characterized by being equipped with a blade holding mechanism that stops power supply to the shutter.