JP2557476B2 - Electromagnetically driven shutter - Google Patents

Description

The present invention relates to an electromagnetically driven shutter that opens and closes a shutter blade of a camera by electromagnetically driving.

[Prior Art] Conventionally, a large amount of mechanical force has been used as a drive source for driving a shutter of a camera. That is, the shutter driving spring is charged at the same time by film winding or the like, and the shutter is driven by the force of this spring in conjunction with the shutter release. Such a mechanical shutter releases the force of the charged spring. A member for locking was provided in front, and a mechanism for releasing this by a release operation was provided. Therefore, in such a camera, there is no accident such that the shutter is opened unintentionally during normal carrying, and there is no risk of such an accident unless the shutter button is pressed with some force. Met.

Further, in the conventional electromagnetically driven shutter, an electromagnetic driving source converts electrical energy into mechanical energy, and the shutter member is driven by this force. Generally, a spring driving force is unnecessary, and a shutter release operation is performed. A driving force is generated by energizing the electromagnetic drive source, and the shutter blade is operated by this. Therefore, it has been considered that a lock member such as a mechanical shutter is unnecessary. However, even in the electromagnetically driven shutter, if gravity, vibration, shock, or the like acts on the shutter blade during carrying or storage, depending on the configuration of the shutter blade, the shutter may be naturally opened, resulting in erroneous exposure of the film. There are accidents that cause accidents, and some measures are required to prevent them. Also, when shooting with an electromagnetically driven shutter camera, it is desirable to cut off the power supply to the electromagnetically driven source to save power during the period from the completion of exposure travel to the start of the next shooting. Since it is held only by frictional force, the above accidents were likely to occur. Further, there is a large variation in the blade start position at the start of exposure, which adversely affects the exposure time accuracy.

Therefore, as described in Japanese Patent Application Laid-Open No. 56-50318, an electromagnetic force is provided separately from the electromagnetic drive source for holding the blade at the start position, and holding and releasing are performed by the adsorption and release operations of the electromagnet. Is proposed.

Further, as described in Japanese Patent Application Laid-Open No. 56-72423, there has been proposed a mechanism in which a blade is held at a start position and a lock member is provided to actuate the lock claw member by a magnetic force.

[Problems to be Solved by the Invention] However, in the one disclosed in JP-A-56-50318, a dedicated electromagnet and a holding member must be provided, which complicates the structure and causes a cost increase. There is a problem that

Further, in the one disclosed in JP-A-56-72423, in order to operate the lock claw member from the engaged state of holding the blade to the released state, it is necessary to provide an electromagnet portion different from that for operating the blade. However, this also causes a cost increase, and it is difficult to balance the magnetic force for operating the lock claw properly.

The present invention is intended to solve the above problems. That is, the present invention has a simple configuration,
It is an object of the present invention to provide an electromagnetically driven shutter that can avoid an increase in cost, can increase the curtain speed, and can shorten the traveling time of the blade.

[Means for Solving the Problems] In order to achieve the above object, the present invention relates to a drive lever that is connected to a shutter blade and that rotates from a start preparation position to allow the shutter blade to travel for exposure. Has a protrusion that allows the pin provided on the drive lever to project into the travel area and retract from the travel area, and the drive lever is provided in a state in which the projection protrudes into the travel area. A brake lever that is pressed down and held in the start preparation position, a spring that applies a biasing force to the brake lever in a direction in which the protrusion of the brake lever projects into the travel area of the pin, and a rotation angle of a predetermined angle from the start preparation position. Motion causes the protrusion of the brake lever to resist the urging force of the spring and to be retracted out of the travel area of the pin of the drive lever. A connecting member for rotating the brake lever and transmitting the turning force to the drive lever after rotating by the predetermined angle, and an electromagnetic drive source for rotating the connecting member connected to the output shaft by energizing the coil. The electromagnetically driven shutter has a feature.

[Operation] According to the above-described configuration, when the connecting member is rotated by energizing the coil of the electromagnetic drive source, the brake lever is rotated, and after the pressing and holding state at the start preparation position with respect to the drive lever is released. Rotational force is transmitted to the drive lever, and the exposure travel of the shutter blade is performed. Therefore, the curtain speed can be increased, and the traveling time of the shutter blade can be shortened.

[Examples] The drawings show an example of the present invention. And the first
8 to 9 show an electromagnetic shutter that performs exposure on both the forward and backward paths, and FIG. 9 shows its electrical configuration.
Figure 10 shows the timing chart.

More specifically, FIG. 1 is a perspective view showing the entire electromagnetically driven shutter, showing a state before the start of forward travel or the completion of return travel, and FIG. 2 is the front view of the shutter in the same state as FIG. It is a figure. FIG. 3 is a front view showing a state in which the electromagnetic drive source portion for controlling the operation of the shutter blade group is removed in the state of FIG.
Brake mechanism, signal contacts, etc. are visible. 4 to 6 are front views showing the movements of the blade drive lever and the brake mechanism, and the electromagnetic drive source portion is omitted.
Of these, FIG. 4 shows immediately after the start of slit exposure, and FIG.
Similarly, FIG. 6 shows the latter half of the slit exposure, and FIG. 6 shows the fully open exposure state. FIG. 7 is a front view of the shutter showing the state before the completion of the outward travel or the start of the backward travel, and FIG. 8 is a front view showing the shutter shown in FIG. 7 from which the electromagnetic drive source portion is removed.

In FIGS. 1 to 8, reference numeral 1 is a shutter base plate, and an opening 1a is provided in the substantial center of the plane. Two
Is a cover plate that is attached so as to face the shutter base plate 1 so as to maintain a constant gap, and has a similar opening (not shown) at a position corresponding to the opening 1a. A blade group 3 and a blade group 4 are provided between the shutter base plate 1 and the cover plate 2 with a partition plate 5 (having an opening 5a at a position corresponding to the opening 1a) interposed therebetween. And each has two blade arms 6 and 7 (the blade arm of the blade group 3 is not shown)
The opening and closing of the opening is performed by the operation of a known link mechanism.

Reference numeral 8 denotes a blade dowel for rotatably connecting the blade and the blade arm, and both blade groups 3 and 4 have the same structure as a blade unit.

Here, since the structure related to the driving of the blade group 3 and the structure related to the driving of the blade group 4 have substantially the same structure and operation, the reference numerals of the parts related to the driving of the blade group 4 are as follows.
It is represented by a numeral obtained by adding 100 to the reference numeral of the drive of the corresponding blade group 3, and is represented by the description of the drive of the blade group 3.

Reference numeral 9 is a drive lever, which is connected by a blade arm pin 9a, and rotates around the axis P to open and close the blade group 3. In addition, a hole 9b for receiving the driving force is provided near the center of the lever, and a pin on the transmission side (planted on the lower surface of the connecting lever 10 and, in the figure, a pin 10c planted on the upper surface of the connecting lever). And the same diameter at the same position) with a predetermined play in the rotation direction around the axis P.

Reference numeral 10 denotes a connecting lever as a connecting member, which is directly connected to the output shaft (coaxial with the shaft P) of the electromagnetic drive source M, and applies the rotational force around the shaft P of the electromagnetic drive source to the lower surface transmission side pin of the pin 10c. Is transmitted to the drive lever 9 and the lower standing bent portions 10a, 10
b has a spring property on the brake lever 11 (3rd
In the drawing, the brake lever 11 is rotated around the axis R in a predetermined direction and a predetermined angle by engaging with the arm portions 11a and 11b which have a spring property in the direction of the arrow A and are hard to bend in the direction perpendicular to the arrow A. Then, the stopper is released at the start of traveling of the blade group 3 and the braking effect is generated at the completion of traveling.

In addition to the above-described structure, the brake lever 11 acts on the side surface of the pin 9a of the drive lever 9, and the projections 11c and 11d that serve as stoppers and brakes, and the spring 15 that is given a turning habit about the axis R. And an arm portion 11e that receives the force of.

Reference numeral 12 is a pin that abuts the side surface of the brake lever 11 and restricts clockwise rotation of the brake lever 11, 13 is a stopper pin that restricts counterclockwise rotation of the brake lever 11, and 14 is a swing lever. Is rotatably supported around an axis T, and a spring 15 is provided at the tip of the lever to give the brake levers 11 and 111 rotational habits around the axes R and S, respectively. Due to the balance, rotation about the axis T is performed.

Rubber stoppers 16 and 17 act on the side surface of the pin 9a of the drive lever 9 to reduce the shock of the blade at the end of traveling of the blade.

Reference numeral 18 denotes a base plate for an electromagnetic drive source, which is made of an insulating and non-magnetic material such as plastic and has an electromagnetic drive source M for driving and controlling the blade group on the upper side and a signal for detecting the traveling state of the blade group on the lower side. With contacts 19,20 and 119,120, screw 21
Thus, the shutter base plate 1 is fixed to the pillar 22. Here, the signal contact pieces 19, 20 have their bases supported by the electromagnetic drive source base plate 18, and their ends are abutted against the pins 23 planted on the lower side of the base plate 18 with pre-tension to determine their positions. There is. Then, the position is within the rotation area around the axis P of the pin 10c, and the contact state is turned ON / OFF in response to the opening / closing operation of the blade group 3 to detect the traveling state of the blade group.

Reference numeral 24 is a yoke of the electromagnetic drive source M, and 25 is a permanent magnet, which is magnetized in the vertical direction in the figure. Reference numeral 26 denotes a movable coil, which is rotatably supported about an axis P and forms a so-called meter-type electromagnetic drive source M that generates a rotating force by generating an electromagnetic force by passing an electric current. There is. Then, by detecting ON / OFF of the above-mentioned contact, the direction of the current to the coil is reversed to reciprocate.

Reference numeral 27 is a pressing plate for fixing the electromagnetic drive source M to the ground plane 18, and is connected to the ground plane 18 by screws 28.

In FIG. 9, PRS is a control circuit, for example, a one-chip microcomputer in which a CPU (central processing unit), RAM, ROM, an input port, a timer circuit, etc. are arranged, and in the ROM, Software such as shutter control and parameters are stored. The boat inputs a switch for detecting the state of the shutter and outputs a shutter communication signal. The timer counts the set time and measures the time of shutter control. SHT is a shutter control circuit, and control signals SSHT1 and SSHT2 from the control circuit PRS
The shutter magnets MG1 and MG2 are energized by and the traveling direction signal SDIR. Shutter magnet MG1
When electricity is applied to the blade group 3, the blade group 3 travels in the direction designated by the traveling direction signal SDIR. After a lapse of time from the start of energization to the completion of traveling of the blade group 3, the energization is stopped.

The same applies to the blade group 4, and when the shutter magnet MG2 is energized by the SSHT2 signal, the blade group 4 is driven.

The shutter state is transmitted from the shutter control circuit SHT to the control circuit PRS by the state signals SSW1 and SSW2.

When the signal contacts 19 and 20 are conductive, SSW1 outputs "H", and when the signal contacts 119 and 120 are conductive, SSW2 outputs "H". Outputs "L" when the wires are disconnected. When SSW1 = "H" and SSW2 = "L", it is before the start of the outbound trip (Fig. 3), and conversely, when SSW1 = "L" and SSW2 = "H", before the inbound trip (before the outbound trip). After completion) (Fig. 8). When the shutter is fully open (Fig. 6), SSW1 = "L"
SSW2 becomes "L".

Next, the operation of the embodiment of the present invention thus constructed will be described.

With FIG. 1 to FIG. 3 as the forward traveling start state, first, so-called battery check is performed to confirm whether or not the battery has enough energy for the camera to operate accurately. At that time, the coils 26 and 126 of the electromagnetic drive source M for controlling the driving of the blade group 3 and the blade group 4 respectively are connected to the rotary shafts P and Q.
A counterclockwise direction, that is, the blades are made to travel around, and a predetermined current is applied for a predetermined time so as to apply a rotational force in a direction (locking direction) opposite to the exposure direction. In this case, both coils 26 and 126 are energized at the same time to check the battery, so that both coils can be operated at high speed.
It reproduces the state of energizing 26 and 126 at the same time (the most severe power supply condition), guarantees the exposure time accuracy, and also checks the disconnection of both coils 26 and 126. However, the battery can be checked even if only one of the coils is energized. If the battery check shows NG (no), the camera stops the sequence and becomes inoperable. Battery check is OK
If (good), the coil 26 of the electromagnetic drive source M for controlling the drive of the blade group 3 (which becomes the front blade when traveling in the forward path) is supplied with a predetermined current so that the coil rotates clockwise about the axis P. Energization is started, and the shutter enters the exposure operation. The rotation of the coil 26 is directly transmitted to the connecting lever 10, and the lever 10 starts rotating around the axis P in the clockwise direction.

At that time, the pin 10c on the lower surface of the connecting lever 10 and the hole 9b of the driving lever 9 have a play on the clockwise rotating side as shown in FIG. The blade group 3 has not yet been transmitted to the lever 9 and remains in the start preparation position. In addition, the brake lever 11 has a spring 15
The side of the lever is brought into contact with the stopper pin 12 while keeping the habit of clockwise rotation about the axis R by
11c is projected into the traveling area of the pin 9a of the drive lever 9 by a predetermined amount, and the pin 9a of the drive lever 9 is pressed into an area formed by the projecting portion 11c and the rubber stopper 17, so that the blade group 3
It regulates fluctuations in the start preparation position.

Immediately after the rotation of the connecting lever 10, the lower side bent portion of the lever 10
10a pushes the tip of the arm portion 11a of the brake lever 11 in a direction substantially perpendicular to the direction of arrow A to move the brake lever 11 to the axis R
Around the, against the habit of clockwise rotation by the spring 15,
Rotates counterclockwise. Then, due to the rotation of the connecting lever 10, the play between the pin 10c on the lower surface and the hole 9b of the drive lever 9 disappears, and when the contact is made, the brake lever 11 is released.
Rotates until the protrusion 11c is retracted to the outside of the traveling area of the pin 9a. For the first time, the rotational force of the electromagnetic drive source M is transmitted to the drive lever 9, the drive lever 9 starts to rotate in the clockwise direction around the axis P, and the blade group 3 starts the opening operation.
At this time, since the connecting lever 10 runs at a certain rotation angle to give momentum, the rising edge of the opening operation of the blade group 3 becomes sharp, which contributes to the improvement of the curtain speed.

Soon after, as shown in FIG. 4, immediately after the blade group 3 starts the opening operation, the connecting lever 10 further rotates the brake lever 11 counterclockwise to engage the lower standing bent portion 10a and the arm portion 11a. Leave. At this time, the brake lever 11 has already been given a turning tendency around the axis R in the counterclockwise direction. It has rocker lever 14 and each brake lever 1
This is because the arm 11e, 111e of 1,111 is rotated clockwise about the axis T to a position where the spring 15 can be spring balanced.

A predetermined exposure time T [seconds according to the number of exposure steps of the camera, for example, 1/2 ⁿ (n is an integer) so that proper exposure can be performed after the energization of the coil 26 for the blade group 3 is started. ) Seconds]
In addition, after adding a time ΔT ₁ (so-called getter tone) that must be adjusted according to the response characteristics of the drive and control system or the traveling characteristics of the blade system peculiar to the shutter unit, the coil 126 for the blade group 4 is added. Energization is started and the closing operation is performed.

Further, as time passes, as shown in FIG. 5, the blade group 3
Just before the end of running, the brake lever 11 already has the habit of counterclockwise rotation by the spring 15,
Place the side of the lever against the stopper pin 13 and
Is projected into the traveling area of the pin 9a of the drive lever 9 by a predetermined amount, and the traveling of the pin 9a is awaited.

When the pin 9a comes into contact with the protrusion 11a, the blade group 3
Therefore, the pin 9a tries to move to the final stop position by rotating the brake lever 11 in the clockwise direction against the tendency of the brake lever 11 to rotate in the counterclockwise direction by the spring 15. .

At the same time, the lower standing bent portion 10b of the connecting lever 10 comes into contact with the side surface of the arm portion 11b having the spring property of the brake lever 11,
While pushing the arm 11b away in the direction of the arrow A, the arm 11b also tries to move to the final stop position. Therefore, the blade group 3 is braked by the spring force of the brake lever 11 and the conversion of energy into rotational movement, and stable running with excellent durability becomes possible. Further, the bounce immediately after the blade group 3 reaches the traveling completion position is the protrusion 11 of the brake lever 11 to which the spring 15 is given the habit of turning counterclockwise.
d presses the pin 9a toward the area formed by the rubber stopper 16 and is removed. Also, the signal contact piece 1 that was in the contact (ON) state before the blade group 3 traveled (Fig. 3).
The blades 9 and 20 are in a non-contact (OFF) state when the traveling of the blade group 3 is completed (FIGS. 6 and 8).

The blade group 4 (which becomes the rear blade when traveling in the forward path) performs exactly the same operation as that of the blade group 3 with respect to driving and braking, except that the blade group 4 performs the closing operation. Then, before the blade group 4 travels (FIGS. 3 and 6), the signal contact pieces 119 and 120 that were in the non-contact (OFF) state are at the completion of traveling of the blade group 4 (FIG. 8). , Contact (ON) state.

The above-mentioned brake mechanism is used in both the slit exposure shown in FIG. 5 and the full-open exposure shown in FIG.
It can operate similarly as described above.

As shown in FIGS. 7 and 8, the outward travel is completed, and the blade group 4 closes the opening to complete the exposure. In this state, the ones involved in the blade group 3 and the ones involved in the blade group 4 are completely reversed, as compared with before the start of the outward travel. In other words, this state is the next homeward traveling start state. Therefore,
The control microcomputer of the camera is the contact piece 19, 20 and 11
Detects that the ON / OFF state of 9,120 is reverse to that before the start of outward travel, and controls the drive of each blade group 3 and 4 so that the traveling direction of blade groups 3 and 4 is opposite to that during outward travel. Coil 26,126
Reverse the energizing direction to.

Hereinafter, the function of each part is reversed in the backward traveling from the forward traveling described above (for example, the protrusion 11d of the brake lever 11 regulates the fluctuation of the start preparation position of the blade group 3, and the protrusion 11
c plays the role of braking and bounce prevention at the end of traveling of the blade group 3, etc.) Since the same operation is performed, only characteristic points will be described.

First, regarding the battery check, each coil is also energized so that a rotational force is applied in a direction (locking direction) opposite to the direction in which exposure is performed on the return trip. On the other hand, the only difference from the outward travel is the geta tone, and the roles of the leading blade and the trailing blade are interchanged in blade groups 3 and 4, so the order of energizing the coils of each electromagnetic drive source M must be changed. However, due to subtle differences in the characteristics of both electromagnetic drive sources M, differences in the same electromagnetic drive source itself due to the difference in rotation direction, differences in blade group operating load due to differences in the blade group traveling direction, etc. Δ
Since proper exposure time accuracy cannot be obtained with T ₁ , it is necessary to provide a separate getter tone ΔT ₂ for the return trip.
Also, the ON / OFF status of 119 and 120 is detected and switched. When the return trip is completed, the condition shown in Fig. 3 is reached and the contact piece 1
Since the ON and OFF states of 9,20 and 119,120 are reverse to those before the return trip start (that is, the same as before the outward trip start), this is detected by the camera control microcomputer and the coils 26,1
The energization direction to 26 is reversed, and the getter tone is switched to ΔT ₁ , and the outward travel start state described at the beginning of the operation description is entered.

Next, the electromagnetic shutter drive will be described based on the timing chart of FIG.

(Time a) Battery is checked by turning on SSHT1 and SSHT2 at the same time. Since the state of the shutter is after the return traveling, the shutter blade group 3 is closed and the shutter blade group 4 is open. Therefore, SSW1 = "H" and SSW2 = "L". In the battery check, the shutter blades are energized in the direction in which the blades do not travel, that is, the blade group 3 is opened → closed and the blade group 4 is closed → opened. Such energization direction is designated by SDIR = "H".

(Time b) Set SDIR = "L" to change the shutter traveling direction after the battery check. Thus, the shutter traveling direction on the outward path is set.

(Time c) When the magnets of the blade group 3 are energized, the blade group 3 travels from the closed direction to the open direction, and becomes the front curtain.

(Time d) When the blade group 3 is opened, SSW1 = "L".

(Time e) Energization of SSHT1 is stopped after a sufficient time for the shutter blades to travel from time C.

(Time f) After a predetermined exposure time T and a get tone ΔT ₁ have been added from time c, SSHT2 = “H” is set, and the blade group 4 runs. When SDIR = "L", the blade group 4 is energized in the open-to-close direction (running the rear curtain).

(Time g) When the blade group 4 is not in the open state, SSW2 = "H".

(Time h) The energization of SSHT2 is stopped after a certain time has passed from time f. In this way, the outward travel of the shutter is completed. At this time, the blade group 3 is opened and the blade group 4 is closed. When the traveling direction SDIR = "L", the blade group 3 is closed → opened, and the blade group 4 is opened.
Remains open → closed.

 Next, traveling on the return path will be described.

(Time i) Check the battery. Since the traveling direction is the same as that at time h, traveling is not performed. The battery is checked at time a and the power is supplied in the reverse direction.

(Time j) After checking the battery, set SDIR = "H" and set the traveling direction in the opposite direction.

(Time k) On the return path, the blade group 4 serves as the front curtain and runs first.

(Time l) When the blade group 4 is opened, SSW2 = "L".

(Time m) SSHT2 stops energization after a certain time from time k.

(Time n) After a lapse of a predetermined exposure time T from time k and the addition of the tone adjustment ΔT ₂ different from the time of the forward path, the traveling of the blade group 3 is started (SSHT1
= "H").

(Time o) When the blade group 3 is no longer in the open state, SSW1 = "H".

(Time p) After a lapse of a certain time from time n, SSHT1 = "L" is set and the energization is terminated.

 In this way, the traveling of the shutter on the return path is completed.

[Effects of the Invention] As described above, according to the present invention, when the connecting member rotates due to the energization of the coil of the electromagnetic drive source, the brake lever rotates, and the pressing and holding operation at the start preparation position with respect to the drive lever is performed. After the state is released, the rotational force is transmitted to the drive lever, and the exposure travel of the shutter blades is performed.Therefore, with a simple configuration that does not increase the cost, the shutter blades are inadvertently moved due to a shock while the camera is being carried. This has the effect of preventing erroneous exposure in which the exposure opening has been opened.

Further, since the shutter blade is accurately held at the start preparation position by the brake lever, it is possible to improve the stabilization of the exposure time accuracy.

Furthermore, since the shutter blade starts moving after the connecting member rotated by the electromagnetic drive source has rotated to some extent, the curtain speed is increased, and the shutter has high performance.

[Brief description of drawings]

The drawings show one embodiment of the present invention. FIG. 1 is a perspective view showing the entire electromagnetically driven shutter, FIG. 2 is a front view of FIG. 1, and FIG. 3 is a state of FIG. FIG. 4 is a front view showing the movement of the blade drive lever and the brake mechanism immediately after the start of slit exposure, and FIG. 5 is a blade drive in the middle of the second half of slit exposure. 6 is a front view showing the movements of the lever and the brake mechanism, FIG. 6 is a front view showing the movements of the blade drive lever and the brake mechanism for the full-open exposure, and FIG. FIG. 8 is a front view of the shutter shown, FIG. 8 is a front view showing the state in which the electromagnetic drive source portion is removed in the state of FIG. 7, and FIG. 9 is an explanatory view showing an electrical configuration in a block diagram. The figure shows the operation timing It is an explanatory diagram showing in bets. 1 ... Shutter base plate, 2 ... Cover plate, 3,4 ... Blade group, 6,7 ... Blade arm 9,109 ... Drive lever, 10,110 ... Connecting member (connecting lever), 11,111 ... Brake lever, 14 ...... Rotating lever, 15 ...... Spring, 18 ...... Main plate for electromagnetic drive source, 26,126 ...... Movable coil, M ...... Electromagnetic drive source.

Claims (1)

(57) [Claims] 1. A drive lever which is connected to a shutter blade and rotates from a start preparation position for exposing and traveling the shutter blade, and a pin provided on the drive lever protruding by rotation into a traveling area. And a brake lever that is retracted to the outside of the travel area, and a brake lever that presses and holds the drive lever in the start preparation position in a state in which the projection portion protrudes into the travel area, and the brake lever described above. A spring that applies an urging force to the brake lever in a direction in which the protrusion projects into the travel area of the pin, and a biasing force of the spring that causes the protrusion of the brake lever to rotate by a predetermined angle from the start preparation position. The brake lever so as to be retracted outside the traveling area of the pin of the drive lever, and after rotating by the predetermined angle, A coupling member transmitting the serial driving lever pivoting force, electromagnetically driven shutter, characterized in that it comprises an electromagnetic driving source for rotating said coupling member coupled to the output shaft by energizing the coil.