JP2008292928A - Imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve such a problem that although a camera 1 to which an external strobe 2 can be attached is provided with a backlash preventing leaf spring 4, for suppressing the attaching backlash of the external strobe 2, when an external force is applied to the external strobe 2, in such a state that the external strobe is attached, the backlash preventing spring 4 is plastically deformed and loses an upward energizing force, so that a detecting means erroneously detects that the external strobe 2 is in an attached state, even when the external strobe 2 is not attached. <P>SOLUTION: A plurality of switch leaf springs 7 provided in the detecting means are stacked one over another to have a reaction force capable of counteracting the plastic deformation of the backlash preventing leaf spring 4, so that the erroneous detection of the attachment of the external strobe can be prevented without increasing the size of the camera 1. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an imaging apparatus to which an external strobe can be attached.

Some conventional imaging devices that can be equipped with an external strobe use a detection lever as detection means for detecting the attachment of the external strobe. In such an imaging device, when the external strobe mounting portion is inserted into the guide groove of the accessory shoe, the external strobe mounting portion pushes down the pin portion via the play preventing leaf spring, and the extension portion of the detection lever is the normally closed switch. Open the contact. In this way, the imaging apparatus can detect the mounting of the external strobe. (For example, see Patent Document 1)
Japanese Patent Laid-Open No. 10-186471

  In the above conventional example, the backlash prevention leaf spring is provided to suppress the mounting looseness of the external strobe, but the clearance between the accessory shoe guide groove and the external strobe mounting portion is very narrow in order to withstand a static pressure load. Therefore, if an external force is applied to the external strobe with the external strobe mounting portion inserted in the guide groove of the accessory shoe, the rattle prevention spring may be plastically deformed, and the upward biasing force may be lost. The extended portion of the deformed backlash prevention leaf spring pushes down the pin portion and the detection lever against the reaction force generated in the leaf spring of the normally closed switch even when the external strobe is not attached. Therefore, there is a problem of erroneously detecting that an external strobe is attached.

  An imaging device according to the present invention includes an accessory shoe to which an external accessory can be attached, a first spring member that is disposed on the accessory shoe and is charged when the external accessory is attached to the accessory shoe, and the accessory shoe. A pin member that is disposed and pushed in when the first spring member is charged; and a second spring member that urges the pin member in a direction in which the pin member protrudes with a stronger urging force than the first spring member. And detecting means for detecting that the external accessory is attached to the accessory shoe when the pin member is pushed.

  Even when the first spring member undergoes plastic deformation, the pin member can be pushed back by the biasing force of the second spring member. Therefore, even if the first spring member is plastically deformed, no erroneous detection is performed by the detection means.

  FIG. 1 is a perspective view of an accessory shoe of an imaging apparatus according to an embodiment of the present invention with an external strobe attached thereto, and FIG. 2 is an external perspective view of the accessory shoe to which the external strobe can be attached. FIG. 3 is an internal perspective view of the external strobe and the detection unit that detects the mounting of the external strobe, and FIG. 4 is a yz cross-sectional view of the pin portion of FIG.

  1 is a camera body, 3 is an accessory shoe disposed on the upper part of the camera body, 4 is a backlash preventing leaf spring (first spring member) for preventing backlash when the external strobe is mounted, and 5 is a pin ( Pin member). The backlash prevention leaf spring 4 has an extending portion 4a having a biasing force in the y direction. The external strobe mounting portion 2a is inserted between the bent portion 3a of the accessory shoe and the extended portion 4a of the backlash prevention leaf spring, and is pressed against the bent portion 3a of the accessory shoe by the urging force of the extended portion 4a. Further, when the extension 4a is charged in the -y direction, the pin 5 is pushed in the -y direction.

  6 is an exterior cover, 7 is a switch leaf spring A (second spring member), 8 is a switch leaf spring B (second spring member), and 10 is a flexible substrate on which an electric circuit is formed. The switch leaf spring A7 and the switch leaf spring B8 are fixed to the exterior cover 6 with screws 9. The root portion 7a of the switch leaf spring A is electrically connected to the conductor exposed portion C10a of the flexible substrate by soldering, the tip portion 7b has a biasing force in the y direction, and the pin 5 protrudes in the y direction, It contacts the conductor exposed portion D10b. That is, when the external strobe 2 is not attached, the conductor exposed portion C10a and the conductor exposed portion D10b of the flexible substrate are electrically connected by the switch leaf spring A7, and function as a normally closed switch.

  The switch leaf spring A7 is also pushed in the -y direction by the pin 5 pushed in the -y direction when the external strobe 2 is attached, and the tip portion 7b of the switch leaf spring A is separated from the conductor exposed portion D10b. For this reason, the normally closed switch that has been made conductive by the switch leaf spring A7 is opened, and the attachment of the external strobe 2 can be detected.

  When a strong external force is applied to the external strobe 2 with the external strobe 2 attached, the extended portion 4a of the backlash prevention leaf spring may be plastically deformed in the -y direction. Further, when the mounting portion 2a of the external strobe that is thicker than the standard is inserted between the bent portion 3a of the accessory shoe and the extension portion 4a of the backlash prevention leaf spring, the extension portion 4a of the backlash prevention leaf spring is in the -y direction. May be plastically deformed. When the extended portion 4a of the backlash prevention leaf spring is plastically deformed in the -y direction, the extended portion 4a deformed even when the external strobe 2 is not attached pushes the pin 5 in the -y direction.

  However, in the present embodiment, the switch leaf spring A7 and the switch leaf spring B8 are pushed by the movement of the pin 5, and the total reaction force generated by the deflection is less than the reaction force generated by the backlash prevention leaf spring 4 with the same deflection amount. Is also set strongly. Therefore, the extension portion 4a of the backlash prevention leaf spring is not bent in the + y direction against the reaction force of the switch leaf spring A7, and the extension portion 4a of the backlash prevention leaf spring is not plastically deformed in the -y direction. With this configuration, the normally closed switch is kept in the normally closed state, and the external strobe 2 is correctly detected as being in the non-mounted state.

  Next, the reason why two switch leaf springs are stacked in order to increase the reaction force of the urging portion provided in the detecting means in this embodiment will be described. The switch leaf spring can be regarded as a cantilever with a screw stopper as a fixed end. A schematic diagram of the cantilever shown in FIG. 5 is shown, and the characteristic is expressed by (Equation 1).

δ：たわみ Ｗ：荷重 ｌ：はり長 Ｅ：ヤング率 Ｉ：断面二次モーメントであり、ヤング率は（式２）で表される。

δ: Deflection W: Load l: Beam length E: Young's modulus I: Second moment of section, Young's modulus is expressed by (Equation 2).

σ：応力 ε：ひずみ
たわみ（δ）は直動するピン５に押されてスイッチ板バネ７に発生するたわみ量であり、荷重（Ｗ）はピン５が当接する位置に発生するスイッチ板バネ７の反力である。はり長（ｌ）はビス止め部からピンが当接する位置までの距離である。

σ: Stress ε: Strain Deflection (δ) is the amount of deflection generated in the switch leaf spring 7 by being pushed by the linearly moving pin 5, and the load (W) is the switch leaf spring 7 generated at the position where the pin 5 abuts. The reaction force. Beam length (l) is the distance from the screw stop to the position where the pin abuts.

Since the amount of movement of the pin 5 is constant, the deflection (δ) = constant, and in order to increase the reaction force (W) of the switch leaf spring 7 under that condition, there is the following method.
a) Shorten the distance (l) from the screw stopper to the position where the pin abuts b) Change to a material with a large Young's modulus c) Increase the cross-sectional second moment (increase the plate thickness)
However, when the distance a) is shortened, the deflection is constant, so that the strain becomes too large, causing plastic deformation beyond the elastic deformation region, and the normally closed switch is normally opened. Similarly, the material having a large Young's modulus of b) and the material of c) having a large plate thickness also cause plastic deformation because the elastic deformation region is narrow. Further, when the above is combined so as not to cause plastic deformation, it is necessary to increase the length, but there is a problem that the camera becomes large. In addition, the reaction force generated in the switch leaf spring can be relatively increased by reducing the thickness of the backlash prevention leaf spring 4, but the attachment backlash of the external strobe, which is the purpose of the backlash prevention leaf spring 4, is suppressed. The effect will be reduced.

  Therefore, in the present embodiment, the reaction force can be doubled by stacking two switch leaf springs, which is stronger than the reaction force generated in the rattle prevention leaf spring 4. Therefore, even when the backlash prevention leaf spring 4 undergoes plastic deformation, the extended portion 4a of the backlash prevention leaf spring bends in the + y direction against the reaction force of the switch leaf spring, and the normally closed switch remains in the normally closed state. It can be correctly detected that the strobe 2 is not attached.

1 is an external perspective view of a camera equipped with an external strobe according to an embodiment of the present invention. Appearance perspective view around the accessory shoe to attach the external strobe External perspective view of the external strobe and the detection unit for detecting the attachment of the external strobe Yz sectional drawing in the pin part of FIG. Schematic of cantilever beam

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Camera 2 External strobe 2a External strobe mounting part 3 Accessory shoe 3a Bending part of accessory shoe 4 Backlash prevention leaf spring 4a Extension portion of backlash prevention leaf spring 5 Pin 6 Exterior cover 7 Switch leaf spring A
7a Root portion of switch leaf spring A 7b Tip portion of switch leaf spring A 8 Switch leaf spring B
9 Screw 10 Flexible substrate 10a Conductor exposed portion C of flexible substrate
10b Exposed conductor portion D of flexible substrate

Claims (2)

Accessory shoes that can be fitted with external accessories,
A first spring member disposed on the accessory shoe and charged when the external accessory is mounted on the accessory shoe;
A pin member that is disposed on the accessory shoe and is pushed in when the first spring member is charged;
A second spring member that urges the pin member in a protruding direction with a stronger urging force than the first spring member;
An image pickup apparatus comprising: a detecting unit that detects that the external accessory is attached to the accessory shoe when the pin member is pushed.   The imaging apparatus according to claim 1, wherein the second spring member is a plurality of stacked leaf spring members.

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