Pressing input device

A spring piece is formed integrally as part of a drive arm that presses an operational body. The spring piece is disposed between a pressing part at which the drive arm presses the operational body and a linkage part that acts a swinging fulcrum. A contact part between the spring piece and a case is positioned closer to the linkage part than the bend bottom end is. When the drive arm swings from an initial orientation to a completely swung orientation, the spring piece can generate an elastic return force. The elastic return force does not largely increase even when the drive arm swings.

CLAIM OF PRIORITY

This application claims benefit of priority to Japanese Patent Application No. 2016-173992 filed on Sep. 6, 2016, which is hereby incorporated by reference in its entirety.

BACKGROUND

1. Field of the Disclosure

The present disclosure relates to a pressing input device that operates an operational body by swinging a drive arm to change the state of an electrically variable part such as a switch.

2. Description of the Related Art

Japanese Unexamined Patent Application Publication No. 2006-92996 describes an arrangement related to a pressing input device (lever driven electrical component). This pressing input device includes, in a case, an operational body that can advance and retreat, a sliding member that is driven by being pushed by the operational body, and a detecting member to which an electric signal is output due to the operation of a sliding member. A drive lever is swingably supported by the case. When an external force is applied to the drive lever and it swings, the operational body is pressed into the interior of the case by the drive lever.

The drive lever of the pressing input device described in Japanese Unexamined Patent Application Publication No. 2006-92996 has a restricting part for preventing an inclination. The driving lever and inclination prevention restricting part abut the contact part of the operational body at an angle. This restricts the inclined operation of the operational body when the operational body is pushed by the drive lever.

The pressing input device described in Japanese Unexamined Patent Application Publication No. 2006-92996 is structured so that when the drive lever is rotated, the operational body is pressed, so an operation force is more easily transmitted to the operational body when compared with a structure in which the operational body is directly pressed. A position at which the operational body is pressed to switch the ON state of a switch mechanism, which is the detecting means provided in the case, to the OFF state or to switch the OFF state to the ON state can be set with respect to the swing angle of the drive lever. This enables a timing to switch the switch mechanism to be easily designed.

However, the structure described in Japanese Unexamined Patent Application Publication No. 2006-92996 lacks a return mechanism that returns the drive lever to its initial orientation as a single component. This is problematic in that the drive lever causes a rattle and rattle noise is likely to occur. Another problem with the structure is that the elastic force of a return spring that protrudes the operational body from the case is used to rotate the drive lever to return it toward its initial orientation, so if a load exerted on the rotational fulcrum of the drive lever is increased, a load used to protrude the operational body from the case becomes excessive, lowering reliability in the operation of the operational body.

A possible solution to the above problems is a structure in which a leaf spring is provided so that the base of the leaf spring is fixed to the case, instead of the drive lever. The leaf spring is warped to press the operational body. In this structure, when the operation force exerted on the leaf string is removed, the leaf spring can return to its initial orientation due to its elastic force.

In this structure, however, the longer a distance by which the leaf string is pressed is, the more the leaf spring is warped and the larger elastic reaction force becomes. This increases the operation load. To reduce the operation load, it is necessary to elongate the leaf string to lower its spring constant. To use the leaf spring in an elastic region for a long time, it is also necessary to elongate the leaf spring to lower internal stress generated when the leaf string is warped. As a result, it becomes difficult to downsize the pressing input device.

SUMMARY

A pressing input device that includes: a fixed part; an operational body supported by the fixed part so as to be capable of advancing and retreating; an electrically variable part, the state of the electrically variable part being changed by the operation of the operational body; and a driving arm that swings around a linkage part linked to the fixed part, the linkage part acting as a fulcrum, in a direction in which the drive arm presses the operational body; the pressing input device according to the present invention is characterized in that a spring piece is attached to the drive arm, the bottom end of the spring piece is positioned between the linkage part and a pressing part at which the drive arm presses the operational body, the spring piece is in contact with the fixing part, and when the drive arm swings in the direction in which the drive arm presses the operational body, the spring piece is deformed so as to warp.

DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

As illustrated inFIG. 1, a pressing input device1in a first embodiment of the present invention has a base2and a case3. As illustrated inFIGS. 2A to 2D, the case3is fixed onto the base2. The base2and case3form a fixed part.

The base2is made of a synthetic resin. A first fixed contact4aand a second fixed contact4bare buried in the base2. The first fixed contact4aand second fixed contact4bare made of a conductive metal plate. The first fixed contact4ais positioned on the X2 side, and the second fixed contact4bis positioned on the X1 side. The first fixed contact4ais exposed from a resin protrusion2aformed on the base2and extends in the Z1 direction. Similarly, the second fixed contact4bis exposed from a resin protrusion2bformed on the base2and extends in the Z1 direction. However, an insulative sliding part2cis formed on the top of the second fixed contact4bon the Z1 side so as to be continued to the top; the insulative sliding part2cis integrally formed from the synthetic resin forming the base2.

An operational body5is accommodated in the case3. The operational body5integrally has an operational protrusion5aextending in the Z1 direction and two sliding parts5bextending in the Z1-Z2 direction, one of which is formed on the X1 side and the other of which is formed on the X2 side. An operation hole3ais formed in the upper surface3bof the case3in the Z1 direction. The operational protrusion5aof the operational body5is inserted into the operation hole3a, and the sliding parts5bare guided in the Z1-Z2 direction by a guiding part formed in the case3so that the operational body5is supported in the case3so as to be movable in the Z1-Z2 direction.

A movable contact6is fixed to the bottom part5cof the operational body5. The movable contact6is formed from a conductive metallic leaf spring. The movable contact6has a first holding part6aand a second holding part6b. The first holding part6aholds the first fixed contact4a, and the second holding part6bholds the insulative sliding part2cand second fixed contact4b.

A return spring7, which is a compressing spring, is provided between the base2and the movable contact6. The return spring7constantly urges the operational body5in the Z1 direction.

In this description, the first fixed contact4a, second fixed contact4b, insulative sliding part2c, and movable contact6constitute an electrically variable part. This electrically variable part is a switch mechanism that is switched between an OFF state, in which the first fixed contact4aand second fixed contact4bare insulated from each other, and an ON state, in which the first fixed contact4aand second fixed contact4bare electrically connected, according to the position of the movable contact6, which moves together with the operational body5. The electrically variable part may be any device if its electric state and the state of an electronic signal can be switched or can change. An example of the electrically variable part is a multi-contact switch mechanism in which a plurality of contacts can make a switchover between an insulated state and an electrically connected state, according to the movement of the operational body5. Another example is a variable resistor the resistance of which changes according to the movement of the operational body5.

A waterproof cap8is attached to the top of the case3in the Z1 direction. As illustrated inFIGS. 2A to 2D, the waterproof cap8covers a clearance between the operation hole3aand the base of the operational protrusion5a, which protrudes from the operation hole3a.

A drive arm10is attached to the case3. The drive arm10is formed from an elastically deformable metallic plate. The drive arm10integrally has a pair of support pieces11at the base with a space left between them in the Y1-Y2 direction. The support pieces11are bent toward the X2 direction. A linkage hole11ais made in each support piece11. A pair of linkage protrusions3care integrally formed on the X1 side of the case3, one of which protrudes in the Y1 direction, and the other of which is protrudes in the Y2 direction. Each linkage hole11ais swingably (rotatably) supported by the corresponding linkage protrusion3c. The linkage hole11aand linkage protrusion3cform a linkage part (seeFIGS. 2A to 2D), which is a swinging fulcrum of the drive arm10. The pair of support pieces11may be disposed so as to slightly press both side of the case3to the extent that the swinging of the drive arm10is not impeded.

Alternatively, the pair of support pieces11may be disposed so as to leave the minimum space between each support piece11and the case3.

The drive arm10has a stopper piece13below the support pieces11(on the Z2 side), which is formed so as to be bent. As illustrated inFIG. 2A, when stopper piece13abuts the side surface3dof the case3, the drive arm10cannot rotate further counterclockwise.

The drive arm10has an operational piece14, which extends from the support pieces11at angle toward the Z1 direction and X2 direction. As illustrated inFIGS. 2B to 2D, a portion at which the lower surface of the operational piece14touches the upper end of the operational protrusion5ais a pressing part15. The position of the pressing part15on the drive arm10slightly differs inFIGS. 2B to 2D. The position of the pressing part15shifts on the drive arm10toward the linkage part12, starting from in the position inFIG. 2Band leading to the positions inFIGS. 2C and 2Din that order.

The operational piece14of the drive arm10has a spring piece16between the pair of support pieces11and the pressing part15. The spring piece16is preferably formed integrally as part of the drive arm10by cutting part of the metallic plate, from which the drive arm10is formed, and raising the cut portion. The spring piece16is bent from its bend bottom end16adownwardly at an angle. The spring piece16is formed to such a dimension that the spring piece16is elastically warped. In an embodiment in which the drive arm10and a spring piece are integrally formed, the bend bottom end16ais the bottom end of the spring piece.

As illustrated inFIG. 1, an angular part3eis formed between the upper surface3band side surface3dof the case3. As illustrated inFIGS. 2A to 2D, the spring piece16slidably is in contact with the angular part3e. This contact portion is a contact part17.

Next, the operation of the pressing input device1will be described.

FIG. 2Aillustrates an initial state in which no external force is exerted on the drive arm10. In this initial state, the spring piece16is in contact with the angular part3eof the case3at the contact part17, in a state in which the spring piece16is warped. Due to the elastic return force of the spring piece16, an initial rotational urging force f0is exerted counterclockwise on the drive arm10. Therefore, the stopper piece13remains in contact with the side surface3dof the case3, stabilizing the orientation of the drive arm10. In this state, the operational piece14of the drive arm10is separated from the operational protrusion5aof the operational body5. Since the initial rotational urging force f0is exerted, it is possible to prevent the drive arm10from rattling in the initial state illustrated inFIG. 2A.

In the initial state illustrated inFIG. 2A, the operational body5has been moved in the Z1 direction due to the elastic force of the return spring7illustrated inFIG. 1, so the first holding part6aof the movable contact6fixed to the bottom part5cof the operational body5holds the first fixed contact4a, and the second holding part6bholds the insulative sliding part2c. Therefore, the operational state of the electrically variable part is the OFF state, in which an electrical connection between the first fixed contact4aand the second fixed contact4bis broken.

In an apparatus in which the pressing input device1is installed, when a to-be-detected part, such as a cam or slider, which is moved by a mechanism, moves and abuts the surface of the operational piece14of the drive arm10on the Z1 side, an operational force F is exerted on the drive arm10so as to swing it toward the case3.

The operational force F causes the drive arm10to swing clockwise with the linkage part12acting as a swinging fulcrum. In the process in which the drive arm10is swung clockwise, the operational piece14abuts the operational protrusion5aat the pressing part15, as illustrated inFIG. 2B. When the drive arm10is further swung as illustrated inFIGS. 2C and 2Din succession in that order, the operational piece14presses the operational body5in the interior of the case3in the Z2 direction.

When the operational body5is pressed in the interior of the case3in the Z2 direction, the second holding part6bmoves from the position at which it has been holding the insulative sliding part2cto the position at which the second holding part6bholds the second fixed contact4b, while the first holding part6aof the movable contact6, which moves together with the operational body5, holds the first fixed contact4a. Then, the first fixed contact4aand second fixed contact4bare electrically interconnected through the movable contact6, switching the state of the electrically variable part to ON.

While the drive arm10is swinging clockwise with the linkage part12acting as a swinging fulcrum, the spring piece16in contact with the angular part3eof the case3at the contact part17is deformed so as to warp with the bend bottom end16aacting as a fulcrum. Due to the elastic return force generated by the warp of the spring piece16, a rotational return force f in the counterclockwise direction continues to act on the drive arm10. Therefore, when the operational force F is removed, the drive arm10swings counterclockwise due to the rotational return force f and returns to the initial orientation as illustrated inFIG. 2A. As a result of the drive arm10returning to the initial orientation, the operational body5also moves in the Z1 direction due to the elastic return force of the return spring7and returns to the initial position.

With the pressing input device1in the first embodiment, the rotational return force f generated by the warp of the spring piece16does not become excessive even when the drive arm10swings clockwise and the drive arm10does not give an excessive operational reaction force even when the drive arm10swings as illustrated inFIGS. 2B to 2Din succession in that order. An amount by which the spring piece16warps when the drive arm10swings clockwise is small, so even if the free length of the spring piece16is short, excessive stress is not exerted on the spring piece16and the fatigue of the spring piece16can be reduced. Even if the spring piece16is short, an appropriate rotational return force f can be given to the spring piece16and its fatigue can be reduced, so the drive arm10can be downsized and the pressing input device1can thereby be downsized.

How the spring piece16is warped will be described below in details.

FIG. 3illustrates an operation of the drive arm10when it swings clockwise. InFIG. 3, the drive arm10in the initial orientation “a” illustrated inFIG. 2Ais indicated by solid lines, and the drive arm10in a completely swung orientation “d” illustrated inFIG. 2Dis indicated by broken lines. A swing angle formed between the initial orientation “a” of the drive arm10and its completely swung orientation “d” is indicated by α. In an embodiment, the swing angle α is slightly larger than 30 degrees.

As illustrated inFIG. 3, when the drive arm10swings clockwise from the initial orientation “a” to the completely swung orientation “d”, the bend bottom end16aof the spring piece16moves along an arc path Φ that has a fixed radius r and also has a center O at the linkage part12.

The bend bottom end16aof the spring piece16is positioned between the pressing part15, which presses the operational protrusion5a, and the linkage part12, which acts as the swinging fulcrum. The contact part17between the spring piece16and the angular part3eof the case3is preferably positioned closer to the linkage part12than the bend bottom end16ais. That is, the contact part17is preferably positioned closer to the swinging fulcrum of the drive arm10than the bend bottom end16ais. Therefore, when the drive arm10swings clockwise from the initial orientation “a” to the completely swung orientation “d”, the bend bottom end16arotates in a direction oriented so as to reduce the amount of warp of the spring piece16.

InFIG. 5, the orientation of the spring piece16of the drive arm10in the initial orientation “a” is indicated by solid lines, and the orientation of the spring piece16of the drive arm10in the completely swung orientation “d” is indicated by broken lines. An angle by which the spring piece16warps while the drive arm10swings from the initial orientation “a” to the completely swung orientation “d” is indicated by β. Preferably, this warp angle β is adequately smaller that the swing angle α, illustrated inFIG. 3, of the drive arm10. Therefore, the drive arm10rotates, starting from the initial orientation “a” inFIG. 2A, as illustrated inFIGS. 2B to 2Din succession in that order, the elastic return force generated due to the warp of the spring piece16only slightly increases and the rotational return force f exerted on the drive arm10also only slightly increases.

As illustrated inFIG. 3, with the pressing input device1in the first embodiment, a relative position between the linkage part12acting as the swinging fulcrum and the contact part17formed between the spring piece16and the case3preferably does not change but remains constant while the drive arm10swings. The bend bottom end16aof the spring piece16moves along the arc path Φ that has the radius r and also has the center O at the linkage part12. The contact part17is preferably positioned between the center O and the drive arm10.

Therefore, when the drive arm10swings clockwise, the spring piece16preferably slides on the angular part3eof the case3at the contact part17. As a result, a length Ld from the bend bottom end16aof the spring piece16to the contact part17in the completely swung orientation “d” illustrated inFIG. 2Dis preferably longer than a length La from the bend bottom end16aof the spring piece16to the contact part17in the initial orientation “a” illustrated inFIG. 2A. That is, as the drive arm10swings clockwise, the spring length contributing to the elastic return force of the spring piece16is elongated, and thereby as the drive arm10swings clockwise, the spring constant is reduced.

While the drive arm10swings from the initial orientation “a” to the completely swung orientation “d”, the spring piece16causes a warp with an angle of β as illustrated inFIG. 5, generating an elastic return force. At the same time, the spring length of the spring piece16is increased from La to Ld, lowering the spring constant. Therefore, while the drive arm10swings from the initial orientation “a” to the completely swung orientation “d”, the rotational return force f is not greatly increased from the initial rotational urging force f0.

FIG. 4Aillustrates a positional relationship between the spring piece16and the contact part17in the initial orientation “a”, andFIG. 4Billustrates a positional relationship between the spring piece16and the contact part17in the completely swung orientation “d”, which is reached when the drive arm10has completely swung clockwise. InFIGS. 4A and 4B, a virtual circle C that passes the contact part17is illustrated, the center of the virtual circle C being the center O of the linkage part12, that is, the center around which the drive arm10swings.

InFIGS. 4A and 4B, the elastic return force, of the spring piece16, which is exerted on a contact point between the spring piece16and the contact part17is indicated as an elastic reaction force fr. The elastic reaction force fr is exerted perpendicularly on the plate surface of the spring piece16. Between the initial orientation “a” and the completely swung orientation “d”, there is a change in the amount of warp of the spring piece16and there is also a change in the spring length. Therefore, the elastic reaction force fr is supposed to change. For convenience of explanation, however, both the elastic reaction force in the initial orientation “a” and the elastic reaction force in the completely swung orientation “d” will be denoted here as fr. In each orientation of the drive arm10, the component force of the elastic reaction force fr in the direction of the tangent of the virtual circle C, the tangent passing the contact part17, is the rotational return force f that causes the drive arm10to rotate counterclockwise.

An angle γ is formed between the orientation of the elastic reaction force fr perpendicularly exerted on the spring piece16at the contact part17and the tangent of the virtual circle C, the tangent passing the contact part17. The angle γ is preferably increased as the drive arm10swings clockwise as illustrated inFIGS. 2B to 2Din succession in that order, and the ratio of the rotational return force f to the elastic reaction force fr is reduced as the drive arm10swings clockwise.

As described above, when the position of the bend bottom end16aand an angle at which the spring piece16of the drive arm10extends are set, it is possible to set the rotational return force f so that as the drive arm10swings clockwise, the rotational return force f is reduced. In addition, when the position of the bend bottom end16ais changed and the angle at which the spring piece16of the drive arm10extends is changed to an arbitrary angle, it is possible to set the rotational return force f so that an amount by which the rotational return force f changes can be changed in response to a change in the swing angle of the drive arm10.

FIG. 6illustrates changes in the rotational return force f generated by the spring piece16when the drive arm10is swung from the initial orientation “a” to the completely swung orientation “d” in a state in which the return spring7and operational body5are removed. That is,FIG. 6illustrates changes in the rotational return force f under a condition in which there is no influence by the return spring7. The horizontal axis inFIG. 6indicates an amount by which the pressing part15of the operational piece14moves in the Z2 direction, and the vertical axis indicates changes in the rotational return force f. With the pressing input device1in the first embodiment, while the drive arm10swings from the initial orientation “a” to the completely swung orientation “d”, the rotational return force f generated due to the warp of the spring piece16, if anything, tends to be lowered.

FIG. 7illustrates a load exerted on a forward path along which the drive arm10swings from the initial orientation “a” to the completely swung orientation “d” and a load exerted on a backward path along which the drive arm10returns from the completely swung orientation “d” to the initial orientation “a”, in a state in which all parts of the pressing input device1are incorporated in it. The horizontal axis indicates an amount by which the operational body5moves in the Z2 direction, and the vertical axis indicates the magnitude of the load exerted on the drive arm10. InFIG. 7, the solid-line curve indicates changes in the load on the forward path and the broken-line curve indicates changes in the load on the backward curve.

With the pressing input device1in the first embodiment, when the drive arm10is swung from the initial orientation “a” to the completely swung orientation “d”, the elastic return force given from the return spring7, which is a compression spring, to the operational body5is increased as illustrated inFIG. 7, but the rotational return force f generated by the spring piece16is gradually lowered as illustrated inFIG. 6. Therefore, an increase in the elastic force of the return spring7is substantially cancelled by the rotational return force f, and the operational reaction force generated when the drive arm10swings becomes substantially constant. If anything, the operational reaction force tends to be lowered as the drive arm10swings clockwise.

FIG. 8illustrates part of a pressing input device101in a second embodiment of the present invention.

With this pressing input device101, a deformed part is formed at the top end of a spring piece116that is bent from the operational piece14of the drive arm10and extends. The deformed part abuts the upper surface3bof the case3, forming a contact part117. When the drive arm10swings from the initial orientation “a” to the completely swung orientation “d”, the top end of the spring piece116preferably slides on the upper surface3bof the case3, shifting the position of the contact part117between the spring piece116and the upper surface3bin the X1-X2 direction.

With this pressing input device101as well, the contact part117is preferably positioned closer to the linkage part12than the bend bottom end116aof the spring piece116is, and the bend bottom end116amoves on an arc path Φ that has a radius R and also has the center O at the linkage part12. Therefore, when the drive arm10swings from the initial orientation “a” toward the completely swung orientation “d”, the warp angle of the spring piece116of the drive arm10is small, so the rotational return force f generated by the spring piece116can be reduced to a value lower than the initial rotational urging force f0in the initial orientation “a”.

With the pressing input device101in the second embodiment as well, therefore, it is possible to reduce the rotational load of the drive arm10.

Although the spring piece16in the first embodiment and the spring piece116in the second embodiment are formed integrally with the operational piece14of the drive arm10, the spring pieces16and116may be formed separately from the drive arm10and may be attached to the operational piece14. In an embodiment in which a spring piece is formed separately and is attached to a drive arm, a part at which the spring piece is combined with, connected to, or fixed to the drive arm10is the base of the spring piece.