JPH0628631U - Electrical conduction mechanism - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide an electrical conduction mechanism capable of saving space and increasing the number of bits or the number of switching contacts without expanding the occupied space. An electrical connection including an electrically conductive member that moves relatively and a plurality of electrical contact pieces, wherein each of the electrical contact pieces forms a conductive / non-conductive state with the electrical conductive member according to the relative position. A mechanism, wherein the electric contact piece is provided at two or more locations separated in the relative movement direction.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an electrical conduction mechanism such as a switch and an encoder using a cord plate and an electrical contact piece slidably contacting the cord plate.

[0002]

[Prior art and its problems]

 In recent cameras, as a means for detecting the focal length of a zoom lens or the subject distance, an electric code plate having conductive / non-conductive lands on the surface and an electric brush is slidably contacted with the conductive / non-conductive lands on the code plate. A conduction means is used. As the focal length detecting means of the zoom lens utilizing this electrical connection means, for example, between a cam ring 20 which is rotationally driven and changes the focal length, and a fixed lens barrel (not shown) facing the cam ring 20. There is one in which a cord plate 66 and a brush group 67 which is in sliding contact with the cord plate 66 are provided (see FIGS. 4 and 5).

In this conventional example, in order to detect the focal length with 4-bit data, a code plate having four conducting / non-conducting lands 67 extending in the rotation direction on the outer peripheral surface of the cam ring 20. A brush group 68, to which 66 is fixed and which includes four contact pieces that independently slide in contact with each pattern, is fixed to a support member 69 that is not constrained by the rotation of the cam ring 20. Each contact piece of the brush group 68 is independently input to the focal length detection circuit 71. The focal point distance detection circuit 71 detects the position of the cam ring 20, that is, the focal length, based on the combination of the ON and OFF states of each contact piece.

The above-mentioned conventional example is an example in which the level of each contact piece of the brush group 68 is independently detected, but in the conventional example shown in FIG. 7, each contact piece of the brush group 88 is electrically connected to each other. In this example, the conductive land 87 of the code plate 86 is independent. In the case of the second conventional example, one of the patterns and the other three conductive lands 87 are electrically connected in different combinations depending on the position of the brush group 88. As described above, in the conventional configuration in which the pattern and the contact piece are provided in parallel in the direction orthogonal to the relative movement direction, there is a problem that the width of the code plate and the brush group in the orthogonal direction becomes wide. Therefore, there is also a problem that when the space in the orthogonal direction is limited, the number thereof, and thus the number of bits, is limited.

[0005]

[The purpose of the device]

 The present invention has been made in view of the above-mentioned problems of switches and encoders using the conventional code plate, which enables space saving and increases the number of bits or the number of switching contacts without expanding the occupied space. The purpose is to provide an electrical conduction mechanism.

[0006]

[Outline of the device]

 The present invention that achieves this object includes an electrically conductive member that moves relatively and a plurality of electrical contact pieces, and each of the electrical contact pieces is in a conductive / non-conductive state with the electrical conductive member according to the relative position. The electrical connection mechanism for forming the electric contact piece is characterized in that the electric contact piece is provided at two or more locations apart from each other in the relative movement direction. Further, the present invention according to claim 2 is provided with a plurality of electrically conductive members and a group of electrical contact pieces that move relative to each other, and the plurality of electrically conductive members are the electrical contact pieces depending on the relative position. An electric conduction mechanism for forming a conduction / non-conduction state with a group, characterized in that the plurality of electric conduction members are provided at two or more locations separated from each other in the relative movement direction.

[0007]

【Example】

 The present invention will be described below with reference to illustrated embodiments. First, an interchangeable lens (zoom lens) 10 of a single lens reflex camera to which the present invention is applied will be described with reference to FIG. An outer fixed cylinder 12 is fixed to the detachable mount 11, and a straight guide cylinder 13 is fixed to the outer fixed cylinder 12. These are fixed members of the zoom lens 10.

The linear guide tube 13 is formed with linear guide grooves 14 and 15 for the front lens group L1 and the rear lens group L2 in the optical axis direction. The rear group frame 17 that holds the rear group lens L2 is provided with a cam roller 19 that projects radially outward, and the cam roller 19 is fitted in the straight guide groove 15.

A cam ring 20 is rotatably fitted on the outer periphery of the linear guide cylinder 13. The cam ring 20 is formed with front group and rear group cam grooves 21 and 22, and the cam roller 19 of the rear group frame 17 fitted in the rectilinear guide groove 15 is simultaneously formed in the cam groove 22. It is fitted. On the other hand, on the outer periphery of the front part of the cam ring 20, a front group moving barrel 24 is relatively rotatably fitted, and a cam roller 25 projecting inward from the front group moving barrel 24 inward in the radial direction of the cam ring 20. The cam groove 21 and the linear guide groove 14 penetrating the cam groove 21 are fitted. A focusing ring 26, which can be rotated from the outside, is further screwed onto the outer periphery of the front group moving barrel 24 by a screw 27, and the front group frame 16 described above is attached to the focusing ring 26 via a pressing ring 28. It is fixed.

A zoom ring 30, which can be rotated from the outside, is fitted around the outer fixed barrel 12. The zoom ring 30 and the cam ring 20 are connected by a connecting pin 31 in the radial direction, and the cam ring 20 always rotates equally to the zoom ring 30. The coupling pin 31 passes through the circumferential elongated hole 32 of the outer fixed barrel 12, and the circumferential elongated hole 32 has a width in the optical axis direction that allows a certain amount of movement of the coupling pin 31 in the optical axis direction. There is. As a result, when the zoom ring 30 is rotated, the cam ring 20 is integrally rotated via the coupling pin 31, and as a result, the rear group frame 17 (rear group frame) (rear The group lens L2) and the front group moving barrel 24 (that is, the focusing ring 26, the front group frame 16, the front group lens L1) move in the optical axis direction for zooming. Further, when the focusing ring 26 is rotated, the front group frame 16 (front group lens L1) moves in the optical axis direction according to the screw 27, and focus adjustment is performed.

In the zoom lens 10 described above, when the position of the cam ring 20 in the optical axis direction is adjusted, the entire front lens group L1 and the rear lens group L2 move in the optical axis direction. Therefore, by adjusting the position of the cam ring 20 in the optical axis direction, the back focus can be adjusted during assembly. In this embodiment, a focus adjusting piece (optical axis moving member) 35 is provided as the back focus adjusting means. The focus adjustment piece 35 is supported on the outer fixed barrel 12 so as to be able to move straight in a direction parallel to the optical axis, and a long hole 36 formed in the peripheral surface in the direction parallel to the optical axis. Has been done. The focus adjusting piece 35 is fixed to the outer fixed cylinder 12 by a fixing screw 39 which penetrates the elongated hole 36 and has a tip screwed into the outer fixed cylinder 12. Therefore, the focus adjustment piece 35 can be adjusted in position in the direction parallel to the optical axis by loosening the fixing screw 39 within the effective length of the elongated hole 36. An inner flange 38 is formed at the front end of the focus adjustment piece 35 so as to pass through the notch 37 of the outer fixed barrel 12 and face the outer fixed barrel 12. A circumferential groove 40 is formed on the inner flange 38, and the circumferential groove 40 is fitted into the circumferential projection 41 formed on the cam ring 20 so as to be rotatable relative to each other. In this embodiment, two focus adjusting pieces 35 (35a, 35b) are provided at opposite positions with the optical axis interposed (see FIG. 2).

The focal length detecting means for detecting the rotational position of the cam ring 20, that is, the focal length that changes due to zooming, is composed of a code plate 60 and two brush groups 51 and 52. These configurations will be described in more detail with reference to FIGS. 1 and 2. The code plate 60 is fixed to the outer circumference of the cam ring 20, and the brush groups 51 and 52 are fixed to the focus adjusting pieces 35a and 35b, respectively. The code plate 60 is extended in the circumferential direction of the cam ring 20 and has two sets of conductive / non-conductive lands (patterns) 61 and 62 in the circumferential direction, which are in contact with the conductive / non-conductive patterns. The ON / OFF information of the brush groups 51 and 52 is sent to the focal length detection circuit 71, and the rotational position of the cam ring 20, that is, the focal length of the zoom lens 10 is detected. The detected focal length is sent to the control circuit of the camera body and used for calculation of the open F value, display of focal length information, and the like. The brush groups 51 and 52 face the cord plate 60 through the through holes 12 a formed in the outer fixed cylinder 12.

The main body of the code plate 60 is formed of an insulating flexible substrate, and two sets of land portions 61 and 62 extending in the circumferential direction are formed on the surface at a predetermined interval. The first and second land portions 61 and 62 are provided at a predetermined interval in the rotation direction of the cam ring, and each of the two land portions 61a, 61b, 62a and 62b outputs 2-bit data of a total of 4 bits. I am configuring. The land portions 61 and 62 are electrically connected to each other via the conductive portion 63.

The brush groups 51, 52 are provided with contact pieces 51a, 51b, 52a, 52b that individually and slidably contact the land portions 61a, 61b, 62a, 62b, respectively. The contact pieces 51a, 51b, 52a, 52b are independently connected to the focal length detection circuit 71. The focal length detection circuit 71 checks the voltages of the four contact pieces 51a, 51b, 52a, 52b, and detects the position of the cam ring 20, that is, the focal length, by the combination of these voltages. In the present embodiment, the contact piece 51a is grounded and is always in conduction with the land portion 61a.

As described above, according to the present embodiment, the 4-bit land portions 61a, 61b, 62a, 62b for detecting the rotational position of 20 are divided into two sets and are arranged in a row in the rotational direction. The width of 60 and the brush groups 51, 52 is narrowed, and the storage space in the optical axis direction is small. Further, in this embodiment, the brush groups 51 and 52 are fixed to the pair of focus adjustment pieces 35a and 52b, respectively. Therefore, since the code plate 60 and the cam ring 20 receive the elastic force of the brush groups 51 and 52 evenly toward the optical axis, the inclination with respect to the optical axis is eliminated.

As described above, in the present embodiment, the code plate and the brush are provided at positions shifted by 180 ° with respect to the rotation angle of the cam ring, but the present invention is not limited to this. Further, the member for fixing the brush is not limited to the focus adjusting piece 35.

Next, another embodiment of the present invention for obtaining an on / off signal from the code plate 80 will be described with reference to FIG. In this embodiment, two pairs of four land portions 81a, 81b, 81c and 81d arranged in parallel are provided in a column, and the contact pieces 83a, 83b, 83c and 83d of the brush 83 are provided on each land. It is characterized in that the portions 81a, 81b, 81c, and 81d are formed so as to be independently in sliding contact with each other. The contact pieces 83a, 83b, 83c, 83d of the brush 83 are electrically connected. The land portions 81a, 81b, 81c and 81d are independently connected to the focal length detection circuit 71.

In the conventional example shown in FIG. 7, the four land portions 87 and the contact pieces of the brush 88 are provided in parallel. As is apparent from comparison with this conventional example, in the second embodiment, two cord plates 80 and two brushes 83 arranged in parallel are provided in a column, so that the width is narrow and the device is mounted in a narrow and small space. It is possible to

Although the present invention has been described based on the illustrated embodiments, the present invention is not limited to these embodiments. For example, the embodiment has four land portions, but it is also possible to configure this with a total of six or more land portions or an odd number of land portions. In the first embodiment, for example, when three focus adjusting pieces 35 are provided at 120 ° intervals, it is possible to provide three sets of lands and brushes together with the focus adjusting pieces 35. In this embodiment, the land portion on the code plate is divided into two sets in the column direction, but one land portion is formed in the vertical direction, and the brush is also divided and arranged in the vertical direction. A configuration may be adopted in which each brush forms a conductive / non-conductive state according to the relative position of the land portion. Further, although the embodiment in which the present invention is applied to the focal length detection has been described, the present invention can also be used to detect a subject distance and can also be used as a switch for switching a plurality of circuits. is there.

[0020]

[Effect of device]

 As is apparent from the above description, in the electrical conduction mechanism of the present invention, the electrical conduction members that relatively move and form different conduction states according to their relative positions are provided separately in the relative movement direction. The width of the electrically conducting member, that is, the dimension in the direction orthogonal to the relative movement direction can be reduced, and the electrically conducting mechanism can be mounted even if the width of the relatively moving member is narrow. .

[Brief description of drawings]

FIG. 1 is a plan view showing an embodiment in which the present invention is applied to a focal length detecting means.

FIG. 2 is a front view of the embodiment.

FIG. 3 is a cross-sectional view showing an upper half of a zoom lens barrel of the single-lens reflex camera to which the embodiment is applied, the main part being longitudinally cut along the optical axis.

FIG. 4 is a plan view showing a conventional focal length detecting means.

FIG. 5 is a front view of the conventional example.

FIG. 6 is a plan view showing an essential part of another embodiment of the present invention.

FIG. 7 is a front view showing a main part of another conventional example of the position detecting means.

[Explanation of symbols]

 10 Zoom Lens 12 External Fixed Cylinder 13 Straight Guide Cylinder 20 Cam Ring 30 Zoom Ring 51, 52 Brush Group 60 Code Plate 61, 62 Land (land) 71 Focal Length Detection Circuit

Claims (3)

[Scope of utility model registration request] 1. An electric device comprising an electrically conductive member that moves relatively and a plurality of electrical contact pieces, wherein each of the electrical contact members forms a conductive / non-conductive state with the electrical conductive member according to the relative position. An electrical conduction mechanism, wherein the electrical contact piece is provided at two or more locations separated in the relative movement direction. 2. A plurality of electrically conducting members and a group of electrical contact pieces that move relative to each other, and the plurality of electrically conducting members are in a conductive / non-conductive state with the group of electrical contact pieces according to the relative position. An electrical conduction mechanism to be formed, wherein the plurality of electrical conduction members are provided at two or more locations separated from each other in the relative movement direction. 3. A cord plate having a land portion that forms a conductive / non-conductive state, and a brush member that slides in contact with the land portion and moves relative to each other.
An electrical conduction mechanism for forming a conduction state different from that of the land portion according to the relative position, wherein the land portion is formed in a column in the relative movement direction, and the electrical contact group is formed in each column. An electrical conduction mechanism characterized by being formed separately corresponding to the land portion.