JPH0342448B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electromagnetic clutch mechanism for a camera that switches and connects clutch gears of a camera drive system and a lens drive system.

In a camera with a built-in motor drive, the drive motor installed inside the mirror box operates the camera drive system, that is, when it rotates in the forward direction, it lifts the mirror and performs the focusing operation, and when it rotates in the reverse direction, it restores the mirror, feeds the film, charges the shutter, etc. is going on.

If such a camera is further provided with an automatic focus adjustment function, the lens drive system must be operated, that is, the lens must be moved toward close range or toward infinity.

In order to operate this lens drive system using the motor inside the camera, the drive system must be switched.

However, in order to switch between the two operations, the switching operation must be performed in a short period of time, and the operation must be reliable. Furthermore, since it is placed in the limited space of the camera body, restrictions are imposed on its shape.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an electromagnetic clutch mechanism for a camera that is suitable for switching drive systems as described above, can be placed in a relatively thin space, and can be switched quickly and reliably.

In order to achieve the above object, the electromagnetic clutch mechanism for a camera according to the present invention connects the driving force from the motor built in the camera body to the gear of the first or second drive system by switching the clutch gear. In an electromagnetic clutch mechanism, a drive pulse generation circuit that generates a pulse signal in accordance with a switching command signal and a coil disposed in a magnetic field of a permanent magnet are energized by the drive pulse generation circuit and its output to swing. an oscillating coil mechanism; a stepping mechanism that converts the oscillating motion of the oscillating coil mechanism into a stepping motion that rotates intermittently in one direction; and detecting a moving end of the oscillating motion of the oscillating coil mechanism. a locking mechanism that performs accurate step positioning by locking the stepping mechanism; and a locking mechanism that converts rotation of the stepping mechanism into linear motion to move the clutch gear to the first or second drive system. and a position detection mechanism that detects that the switching mechanism has switched to the first or second drive system and stops the pulse signal of the drive pulse generation circuit. .

According to the above structure, the object of the present invention can be completely achieved.

Hereinafter, the present invention will be explained in more detail with reference to the drawings and the like.

FIG. 1 is a perspective view showing an embodiment of the electromagnetic clutch mechanism for a camera according to the present invention, FIG. 2 is a rear view, and FIG.
The figure shows the main parts of the mechanism.

The gear 1 meshes with a gear train connected to a camera drive system (not shown), and a gear 2 is provided coaxially with the gear 1. The gear 2 can mesh with the clutch gear 5. The gear 3 is a gear to which rotation from a drive motor (not shown) is transmitted, and meshes with a clutch gear 5. The clutch gear 5 is integrally fixed to the clutch shaft 4, and is connected to the clutch shaft 4 via a coupling 7. A clutch gear 8 is provided. A spring 6 is inserted between the clutch gears 5 and 8, and biases the clutch gears 5 and 8 in a direction to separate them. The spring 6 and the coupling ring 7 are such that when the clutch shaft 4 is switched upward or downward, the clutch gear 5 and the gear 2 or the clutch gear 8 and the gear 9 are in contact with each other, so that the ridges of the teeth of the clutch gear 5 and the gear 2 or the clutch gear 8 and the gear 9 come into contact with each other. When you can't mesh right away,
Once the movement of the clutch shaft 4 is absorbed by the spring 6 and the coupling 7, and when the clutch gear 5 and the clutch gear 8 rotate due to the rotation of the gear 3, the phase of the clutch gear 5 and the gear 2 or the clutch gear 8 and the gear 9 changes. These gears are provided so that the respective gears mesh with each other due to the biasing force of the spring 6 when the gears are aligned.

The gear 9 meshes with a gear train connected to a lens drive system (not shown).

The hollow coil 32 is a flat coil,
Electricity is applied through the coil terminals 16 and 17. The hollow coil 32 is held by a coil holding member 31. The coil holding member 31 is pivotally supported by a fixed portion, and is biased counterclockwise in FIG. 1 by a spring 26. The hollow coil 32 is placed in a strong magnetic field created by permanent magnets 33 and 35 arranged side by side on the back side and a yoke 34 arranged on the front side, and when energized by the coil terminals 16 and 17, it becomes a spring. A rotational force is applied in the clockwise direction against 26.

The coil holding member 31 is integrally provided with a fan-shaped gear 29 having teeth on a part of its circumference, and the gear 29 meshes with the pinion gear 28 to increase the rotational speed.

A gear 25 is pivotally supported on a shaft 28a of the pinion gear 28, and a ratchet gear 36 is attached to the gear 25.
are integrated. A pawl 27 is engaged with the ratchet gear 36 and urged counterclockwise in FIG. 1 by a spring 37. Further, as shown in FIG. 2 when FIG. 1 is viewed from the back side, a ratchet gear 40 is integrally fixed to the shaft 28a. A pawl 38 is pivotally supported on the gear 25, and the pawl 38 is biased by a spring 39, and the pawl 38 and the tip thereof are connected to the ratchet gear 4.
It is designed to mesh with 0. Therefore, when the pinion gear 28 rotates in the direction a in FIG.
The ratchet gear 40 rotates the gear 25 in the direction a in FIG. 2 via the pawl 38. Conversely, when rotating in the direction b in FIG.
escape and do not mesh, and the ratchet gear 36 on the front side is locked by the pawl 27, so the gear 25 does not rotate in the direction of FIG. 2b.

The gear 25 meshes with the pinion gear 19,
Furthermore, the rotation speed is increased. In FIG. 1, gear 25 and pinion gear 19 are shown separated for ease of understanding. The speed increasing ratio by the gear 25 and the pinion gear 19 is such that the pinion gear 19 rotates half a turn each time the hollow coil 32 swings.
It is set to rotate 180 degrees. Therefore, when the hollow coil 32 reciprocates twice, the pinion gear 19 rotates once.

A roller 18 is installed at an eccentric position on the back side of the pinion gear 19, and the roller 18 is inserted into the notch 14 of the slide plate 12. Therefore,
On the slide plate 12, a pinion gear 19 moves upward or downward every half turn.
A shaft 4 is connected to the slide plate 12, and the clutch mechanism is switched by vertically moving the clutch gears 5 and 8 together by vertically moving the slide plate 12.

Next, the locking lever 22 will be explained. The locking lever 22 is pivotally supported by a shaft 21, and is biased counterclockwise in FIG. 3 by a spring 20. Therefore, the locking portion 23 at the tip of the locking lever 22 can mesh with the locking gear 24 provided integrally with the gear 25. The locking lever 22 falls clockwise in FIG. 3 due to the tensile force of the spring 20 when the coil holding member 31 swings, but this position is exactly when the eccentric roller 18 of the pinion gear 19 is at the top or bottom dead center position. Therefore, even when the hollow coil 32 swings at high speed, the inertia of the pinion gears 28, 25, 19, etc. that are connected to the hollow coil 32 prevents the slide plate 12 from moving too far, resulting in a so-called overrun. This allows for accurate switching and extremely stable operation.

Position switches 13 and 15 are mounted on slide plate 12
This is a switch that turns on and off by coming into contact with a pin 11 planted in the switch. When the slide plate 12 moves upward and the clutch gear 5 meshes with the gear 2, the switch 13 turns on and the slide plate 12 moves downward. When the clutch gear 8 engages with the gear 9, the switch 15 is turned on, confirming that the clutch has been switched. As a result, by inputting intermittent pulses to the logic circuit described later, the
Which drive system is being switched to can be electrically detected.

FIG. 4 is a circuit diagram showing an embodiment of a circuit for operating an electromagnetic clutch of a camera according to the present invention.

In the circuit shown in FIG. 4, 41 is an input terminal into which a signal for switching the electromagnetic clutch in the direction shown in FIG. 2 is input, 42 is an input terminal into which a signal for switching the electromagnetic clutch in the direction shown in FIG. is a NAND gate, and 46 is a power transistor. 13 and 15 are the aforementioned position switches, and 32 is the aforementioned hollow coil.

First, assume that the switch is in the direction shown by the broken line in FIG. At this time, the position switch 13 is off and the position switch 15 is on. Second
When switching the clutch in the direction shown in the figure, a high level signal is input to the input terminal 41. At this time, since both terminals of the NAND gate 43 are at high level, its output becomes low level. Further, both the terminal and the terminal of the NAND gate 44 become low level, and the output thereof becomes high level. Therefore, Nand Gate 45
The terminal of will be at low level, the terminal will be at high level, and its output will be at high level. For this reason,
Transistor 46 turns on and hollow coil 32
is energized.

When the hollow coil 32 is energized, the hollow coil 3
2 rotates clockwise in FIG. 1 around the coil holding member 31, the pinion gear 28 rotates counterclockwise around the shaft 28a, and the
The rotation in the direction a in FIG. 2 causes the gear 25 to rotate in the direction of the arrow. As the gear 25 rotates in the direction of the arrow, the pinion gear 19 rotates counterclockwise, moving the slide plate 12 in the direction of the roller 18. Therefore, the clutch gear 5 meshes with the gear 2, turns off the position switch 15, and turns on the position switch 13. Therefore, the terminal of the NAND gate 43 in FIG. 4 becomes low level,
Its output becomes high level, and the NAND gate 44
Since the terminal becomes high level and its output becomes high level, both input terminals of NAND gate 45 become high level and its output becomes low level. Therefore, the transistor 46 is turned off and the hollow coil 32 is de-energized.

To switch the clutch in the direction shown in Figure 2,
A similar operation is performed when a high level signal is input to the input terminal 42.

FIG. 5 is a circuit diagram showing another embodiment of the circuit for operating the electromagnetic clutch mechanism of the camera according to the present invention.

In the circuit shown in FIG. 5, 47 and 48 are input terminals, and 49 and 50 are NAND gates. A switching signal from a CPU (not shown) is connected to the input terminal 47, and a reference pulse signal is connected to the input terminal 48. The reference pulse signal is a repetitive pulse consisting of an on time of t ₁ required for the clutch to actuate and an off time of t ₂ required for the hollow coil 32 to return. Input terminal 47
When a high-level signal commanding switching is input, the transistor 46 is intermittently turned on by the reference pulse during that time, energizing the hollow coil 32,
Move the clutch in the direction and direction repeatedly. At this time, when the position switches 13 and 15 reach the desired switching signal, the signal at the input terminal 47 is set to low level, the NAND gate 49 is closed, and switching at the required position is completed.

As explained in detail above, according to the present invention,
Since it uses an oscillating coil mechanism, it can operate in a short time, and the clutch mechanism can be placed in a relatively thin space.Furthermore, the stepping mechanism and locking mechanism ensure reliable operation. be.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing an embodiment of the electromagnetic clutch mechanism for a camera according to the present invention, FIG. 2 is a rear view, and FIG.
The figure shows the main parts of the mechanism. 4 and 5 are circuit diagrams each showing an embodiment of a circuit for operating the electromagnetic clutch mechanism of a camera according to the present invention. 1, 2, 3...Gear, 4...Clutch shaft, 5,
18...Clutch gear, 6...Spring, 7...Coupling, 9...Gear, 10...Bend portion, 11
...Pin, 12...Slide plate, 13,15...
Position detection switch, 14...notch, 16, 17
... Coil terminal, 18 ... Roller, 19 ... Pinyon gear, 20 ... Spring, 21 ... Shaft, 22 ...
Locking lever, 23...Latching portion, 24...Latching gear, 25...Gear, 26...Spring, 27...Claw,
28... Pinyon gear, 29... Gear, 31...
Coil holding member, 32...Hollow coil, 33,3
5...Permanent magnet, 34...Yoke, 36...Ratchet gear, 37...Spring, 38...Claw, 39...
...Spring, 40...Ratchet gear, 41, 42,
47, 48...Input terminal, 43, 44, 45, 4
9,50...Nand Gate.

Claims (1)

[Claims] 1. A pulse signal is generated in accordance with a switching command signal in the camera's electromagnetic clutch mechanism, which switches and connects the driving force from the motor built into the camera body to the first or second drive system gear by switching the clutch gear. a drive pulse generation circuit that causes a swinging motion of the swinging coil mechanism; A stepping mechanism that unilaterally converts into a stepping motion that rotates intermittently, and a moving end of the swinging motion of the swinging coil mechanism are detected and the stepping mechanism is locked to ensure accurate stepping. a locking mechanism for positioning; a switching mechanism for converting the rotation of the stepping mechanism into linear motion to switch the clutch gear to the gear of the first or second drive system; An electromagnetic clutch mechanism for a camera, comprising a position detection mechanism that detects switching to a second drive system and stops the pulse signal of the drive pulse generation circuit.