JP2006145235A - Fall sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fall sensor that is capable of maintaining stable operation for a long period as a movable electrode and suitable for practical use. <P>SOLUTION: In the fall sensor 1, the movable electrode 5 is sealed in an electrically conductive container 2. The movable electrode 5 is provided with a coil spring 9 and, for example, with a plurality of spherical bodies 10. In the coil spring 9, a base end part 9a is connected to by an electrically conductive adhesive and fixed at the inner end part of an electrically conductive pin 4 introduced into the container 2 and supported at one end. The plurality of spherical bodies 10 are movably provided in the inside of the coil spring 9 in a state of being prevented from coming off and function as weights. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a drop sensor that detects a fall state.

  Conventionally, in order to protect a hard disk built in a device such as a portable computer from damage caused by a drop impact, a fall sensor for detecting a fall state is incorporated in the device, and the head of the hard disk is moved to a retracted position based on the detection signal. It is dealt with by moving it. Therefore, this type of drop sensor is required to be miniaturized so as to be incorporated inside the device, and connected to one end of a conductive pin with the other end facing outside in a conductive cylindrical container that functions as a fixed electrode. In addition, a single bar-like spring member cantilevered in the horizontal direction is provided, and a steel ball as a weight is provided on the free end side of the spring member so as to function as a so-called movable electrode that contacts and separates from the container. (For example, refer to Patent Document 1).

  Therefore, in a normal stationary state, the spring member is mainly bent by the gravity of the steel ball, and the steel ball contacts the inner surface of the container to form an electric circuit. On the other hand, when the steel ball is dropped, the apparent gravitational acceleration decreases and the steel ball becomes almost weightless, so that the spring member is elastically returned to the horizontal free state by the elastic restoring force as the spring force of the spring member. As a result, the falling state can be detected based on the fact that the steel ball is separated from the inner surface of the container and the electric circuit is cut off.

In addition, a drop sensor having a similar function has been devised by using a compression coil spring as the spring member, and in particular, a cylindrical weight is inserted into the outer peripheral portion of the coil spring and overlapped. In addition, a device that can be reduced in size by further shortening the length has been devised (for example, see Patent Document 2).
JP 2000-195206 A (page 3 and FIG. 3) JP 2001-185012 (Page 3 and FIG. 1)

  However, when the spring member as in Patent Document 1 is a single bar spring, when the cantilevered free end side is bent and deformed by a weight during a drop impact, bending stress or the like is concentrated on the bar spring. It is easy to be partly plastically deformed or buckled. Therefore, the normal position cannot be maintained during long-term use, and there is a problem in durability such as causing an unstable switching operation as a movable electrode. In addition, when the size of the drop sensor is further reduced, the weight of the steel ball and the spring force of the spring member are reduced because of unstable factors (for example, poor contact) due to the contact pressure between the steel ball as the electrode and the container becoming minute. ), The flexibility of the spring member, the durability mentioned above, and the fact that the weight is spherical, it is not easy to design and manufacture them in a well-balanced manner. It is not suitable for thinning.

  On the other hand, in the configuration using the compression coil spring as the spring member as in Patent Document 2, the spring force can be reduced, and it can effectively act to reliably return to the free state when dropped, and the design of the coil spring and the weight is designed. The degree of freedom is broadened. In addition, since the coil spring is rich in flexibility, it is effective in preventing local buckling phenomenon such as the above rod-shaped spring member, and the length dimension is shortened compared to this rod-shaped spring member. Has the advantage that necessary and sufficient bending deformation can be obtained.

  However, the configuration in which a cylindrical weight is provided on the circumferential side of the coil spring is effective in reducing the length dimension, but there is a limit in reducing the thickness direction (height). For example, a drop sensor The total thickness (which is also the diameter) is limited to about 5 mm, and in addition, it is not always easy to make a small size with high precision by applying gold plating with a specially shaped weight as an electrode, and assembly is also not possible There was also a problem that became complicated. Furthermore, the coil spring is superior to the rod-shaped spring member in that it does not easily cause plastic deformation due to buckling. However, when dropped, the weight of the weight is impacted on the coil spring and the direction of impact is also strange. For this reason, there is a concern that plastic deformation is caused in a part of the coil spring, which causes unstable operation or is difficult in terms of durability.

  In any of the above conventional configurations, the weight strikes the container vigorously and generates an abnormal sound during a drop impact, and the contact point is concentrated at almost one point. There is a possibility that a stable electric circuit may not be formed, such as when an oxide film is formed during use, and this is a disadvantage in practical use, especially when the size is reduced and the spring force is reduced and the contact pressure is also reduced. Also had.

  In order to solve the above-mentioned problems, the present invention provides a practical drop sensor suitable for practical use, which can be downsized while suppressing buckling and plastic deformation of a coil spring at the time of dropping, and can be expected to be a long-term stable operation as a movable electrode. With the goal.

  In order to solve the above problems, the drop sensor of the present invention is a drop sensor in which a movable electrode is sealed in a conductive container, and the movable electrode has an end of a conductive pin whose base end is inserted into the container. The main feature is a structure comprising a coil spring connected and fixed to a portion and cantilevered, and a weight that is movable inward of the coil spring and is housed in a retaining state.

  According to the above means, since the weight is movably provided in the coil spring, it functions effectively as a movable electrode without hindering the bending deformation of the coil spring, and the weight serves as a core member of the coil spring. It is possible to suppress a large deformation that leads to buckling deformation or plastic deformation of the coil spring when dropped. Moreover, since the weight is housed, there is no portion projecting in the radial direction from the coil spring, which is more advantageous for reducing the thickness and reducing the size of the electrode configuration. In addition, a damping action that swings in the vertical direction is generated at an intermediate portion of the coil spring, which is effective for buffering a sudden collision with the container and reducing durability and collision noise.

  Furthermore, each time the free end of the coil spring comes into contact with the container, the coil spring expands and contracts in the length direction and slides on the contact surface. So-called wiping effect removes dirt and oxide film on the contact surface. Even if there is a tendency that the contact pressure of the electrode is reduced due to miniaturization, a long-term stable switching operation can be expected.

(First embodiment)
A first embodiment of the present invention will be described below with reference to FIGS.
FIG. 1 is a sectional view showing the entire configuration of the drop sensor 1 and shows a normal use state (stationary state). FIG. 2 is a diagram corresponding to FIG. FIG. 2 is a cross-sectional view taken along the line AA in FIG. 2, and the configuration will first be described based on these drawings.

The drop sensor 1 is housed in a horizontally arranged state as shown in FIG. 1, for example, in a portable computer (not shown) such as a notebook computer.
The drop sensor 1 generally includes an elongated cylindrical container 2, a sealing member 3 that electrically and airtightly closes an opening at one end of the container 2, and the container 2 that penetrates the sealing member 3 in an airtight manner. The conductive pin 4 led in and out of the inside of the container and the movable electrode 5 connected and fixed to one end of the conductive pin 4 inside the container 2 are provided.

More specifically, the container 2 is made of a conductive metal and has an elongated cylindrical shape that is open at only one end (the left end in the drawing), and functions as a fixed electrode as will be described later.
The sealing member 3 is composed of a cylindrical frame 6 and an electrically insulating sealing material 7 such as glass filled inside, and the conductive pin 4 is hermetically sealed at the horizontal center. It penetrates. However, the frame body 6 is mounted and fixed inside the opening of the container 2 by press fitting. Before the press fit, the inner surface of the container 2 and the outer peripheral surface of the frame body 6 are plated with nickel, gold or gold alloy in advance. The two plating layers are integrated by press fitting, and the airtightness can be further improved (or the frame 6 and the container 2 may be welded by laser welding). Accordingly, the container 2 is configured as a sealed container, and the conductive pins 4 are electrically disconnected from the container 2, and the inside of the container 2 is evacuated, or nitrogen gas, helium gas, etc. The anti-oxidation gas is sealed so that the inner surface of the container 2 as a fixed electrode is not oxidized for a long time.

  The structure of the movable electrode 5 will be described below. The movable electrode 5 is disposed in the sealed container 2 as described above, and can be electrically connected to and separated from the container 2 upon receiving a drop or impact. A conductive disc-shaped spring seat 8 and a horizontally long coil spring 9 are sequentially connected to the inner end where the conductive pin 4 is introduced, and a spherical body 10 as a weight is accommodated in the coil spring 9. Consists of configuration. The coil spring 9 is a cylindrical compression coil spring made of a conductive metal such as phosphor bronze or stainless steel, and the weight of the sphere 10 is added to the free end side which is cantilevered so that the coil spring 9 is reliably bent. The container 2 is in electrical contact with the container 2 and is maintained in a conductive state as shown in a normal use state.

  In the present embodiment, the sphere 10 is composed of a plurality of, for example, five steel balls, and is movably accommodated in a cylindrical coil spring 9. That is, as shown in FIG. 2, the diameter D1 of the sphere 10 is smaller than the inner diameter D2 of the coil spring 9 (D1 <D2), and the total length L1 of the five spheres 10 housed is The configuration is substantially shorter than the effective free length L2 (L1 <L2), so that the sphere 10 is housed in a freely moving state in the coil spring 9, and protects the coil spring 9 as a core member as will be described later. It also has a function to do. Therefore, the free length L2 corresponds to the free length dimension of the coil spring 9 in the range in which the sphere 10 can move. The diameter D1 of the sphere 10 is set to be 1/2 or more of the inner diameter D2 of the coil spring 9 (D1> D2 · / 2). This prevents the individual steel balls of the sphere 10 from overlapping in the vertical direction. It is always aligned next to each other in the horizontal direction to ensure smooth movement.

  By the way, the base end portion 9a of the coil spring 9 is connected and fixed to the cylindrical portion 8a of the spring seat 8 with a conductive adhesive and is cantilevered. The spring seat 8 is made of metal, and the conductive pin 4 is connected and fixed to the center of the left end surface shown in the figure. The cylindrical portion 8a formed on the right end surface has an outer diameter that is the inner diameter of the coil spring 9. It is substantially equal to D2, and thus the base end portion 9a of the coil spring 9 is fitted as a tightly wound portion and connected and fixed with a conductive adhesive.

  On the other hand, the free end portion, which is the other end of the coil spring 9, cannot hold the sphere 10 in the accommodated state in the cylindrical opening state having the inner diameter D2 described above. In order to obtain a small-diameter sealing port shape, a tapered winding portion 9b having a conical shape is formed by close winding, and means for preventing the spherical body 10 as a so-called weight is provided. Therefore, when the coil spring 9 is connected to the spring seat 8, the spherical body 10 is stored in advance from the opening on the base end portion 9a side, and then connected and fixed.

  Thus, the drop sensor 1 is assembled and configured, and the coil spring 9 is arranged in a beam shape by cantilever support, and the sphere 10 made of a plurality of steel balls movably provided inward is formed of a coil. It functions effectively as a weight that elastically bends and deforms the spring 9 and tilts downward from the horizontal axis in the container 2 in the installed state shown in FIG. The contacted displacement state is maintained. However, the drop sensor 1 having such a configuration is arranged on a conductive pattern (not shown) of the printed board 11 indicated by a two-dot chain line in the drawing, and one end of the conductive pin 4 led to the outside has, for example, a lead The wire 12 is electrically connected by soldering, and an L-shaped metal contact 13 is connected to the cylindrical bottom of the container 2 on the other end side by welding, so that it is electrically connected to the printed board 11 respectively. An electric circuit is formed.

Accordingly, an electric circuit that is normally conducted is formed by contact between the coil spring 9 and the container 2, and the spherical body 10 that is movably accommodated does not hinder the bending deformation of the coil spring 9, and thus is one piece. The coil spring 9 that is held and accommodates the spherical body 10 functions as a so-called movable electrode 5, while the container 2 fixedly provided on the printed circuit board 11 functions as a fixed electrode, which constitutes a so-called switching mechanism. ing.
The printed circuit board 11 is fixed inside the portable computer device and is electrically connected to a CPU (not shown). When the lead wire 12 and the contact 13 are electrically connected, a conduction signal is output from the printed circuit board 11 to the CPU. The

Next, the operation of the drop sensor 1 having the above configuration will be described.
The operation state of the drop sensor 1 incorporated in the portable computer is in a stationary state where the central axis is substantially horizontal as shown in FIG. 1, and the gravity of the sphere 10 is cantilevered. The beam-like coil spring 9 is elastically bent and its free end is in contact with the inner surface of the container 2. Accordingly, the lead wire 12, the conductive pin 4, and the coil spring 9 containing the sphere 10 as the movable electrode 5, the container 2 as the fixed electrode, and the contact 13 are electrically connected, and function as a so-called normally closed switch. Then, an electrical path to the printed circuit board 11 is formed and a conduction signal is output to the CPU.

  On the other hand, in the drop sensor 1 when the portable computer is in the fall state, the contact between the coil spring 9 and the container 2 is dissociated as shown in FIG. That is, when entering the fall state, the gravity applied to the sphere 10 apparently decreases, so that it is displaced so as to be returned to the center side of the container 2 by the elastic restoring force that is the spring force of the coil spring 9. Therefore, when the gravity acting on the sphere 10 is reduced to a predetermined value, the free end side of the coil spring 9 is completely dissociated from the inner surface of the container 2, and the lead wire 12 and the contact 13 are electrically completely separated. And the conduction signal from the printed circuit board 11 is turned “OFF”.

  Then, when the CPU detects “OFF” of the conduction signal, the CPU outputs an abnormal signal to an internal drive circuit (not shown). This drive circuit, for example, drives the head of an internal hard disk, moves the head to the retracted position based on detecting an abnormal signal, and stops reading or writing data and programs from the hard disk. In addition, avoidance processing is performed to minimize the risk of damage to the magnetic data and the head.

Further, the characteristic features of the above-configured and operating drop sensor 1, particularly the movable electrode 5, will be described with particular reference to FIGS. 4 and 5.
In the present embodiment, the sphere 10 made of five steel balls obtains the necessary gravity as a weight. In particular, the spherical body 10 is accommodated so as to be sufficiently movable in the free length direction and has a spherical shape, and thus does not have a resistance that inhibits the bending deformation of the coil spring 9. In addition, the spherical body 10 functions as a core member loaded in the coil spring 9 and acts as a resistor that effectively suppresses large buckling or plastic bending of the coil spring 9 when it is dropped. .

Furthermore, the damping action as shown in FIG. 4 is achieved. 4 (a) and 4 (b) show the schematic configuration of the main part of this embodiment, and FIG. 4 (c) shows the schematic configuration of the main part of the conventional example.
First, the above-described damping action will be described with reference to FIG. 4 (a). The cantilever-supported cylindrical horizontally long coil spring 9 in this embodiment is in a form that is elastically deformed downward toward the free end side. The sphere 10 consisting of five components is accommodated from the top to ensure a reliable contact state with the container 2 to ensure the necessary weight. However, the base end portion 9a of the coil spring 9 is connected and fixed, and its free end abruptly contacts (collises) with the container 2. At this time, the intermediate portion of the coil spring 9 is elastically deformed in the vertical direction. Thus, by swinging up and down as indicated by an arrow Y in the figure, the impact caused by the collision can be received in a buffering manner, and a so-called damping effect by a damping action can be obtained. Moreover, in this case, the free end portion of the coil spring 9 is maintained in contact with the inner surface of the container 2, and frequent bounce (repetitive collision operation) is avoided and vibration is greatly reduced.

  Furthermore, the movable electrode 5 is connected and fixed by tightly winding the base end portion 9a of the coil spring 9 in the present embodiment as shown in FIGS. Because of the structure, not only the mechanical strength increases, but also it can be appropriately diffused without concentrating the bending stress at the time of dropping impact and ensure flexibility, thus making it more difficult to cause plastic deformation and buckling deformation. Yes.

  On the other hand, it is effective to prevent the oxidation by enclosing, for example, nitrogen gas or the like in the airtight container 2, but the inner surface of the container 2 or the coil spring 9 may be deteriorated due to oxidation or contamination of the contact portion before the enclosure or long-term use. There is a possibility that the surface of the electrode such as a contact portion may be oxidized or soiled and stable conduction may not be obtained. On the other hand, in this embodiment, as shown in FIG. 4 (b), the coil spring 9 in which the spherical body 10 is movably accommodated collides with the container 2, and as a feature of the coil spring 9 along with the damping action, the length direction Since the elastic expansion and contraction action (indicated by the arrow X direction in the figure) is exerted in the (left-right direction), a so-called wiping effect is obtained in which the contact portion slides left and right when subjected to vibration and a drop impact. Dirt and oxide films can be removed, and therefore a long-term stable switching operation is performed even when the electrode contact pressure tends to decrease due to miniaturization.

  In contrast to the above-described embodiment, in the conventional example shown in FIG. 4 (c), a steel ball weight rod is provided on one rod-like spring member a that is cantilevered. Contact with the container C is performed at one point below the center of gravity position G. Accordingly, as already described in the prior art, a single spring member a is easily buckled and the tendency becomes more prominent as the spring force is reduced by reducing the diameter of the rod member. Since it is unsuitable and unreasonable to reduce the weight, naturally the weights are also restricted by downsizing. In addition, since contact is made at one point below the center of gravity position G of the weight B, there is a concern that a stable conduction state may not be obtained if these contact surfaces become dirty or oxidized after long-term use. It is extremely disadvantageous for conversion.

  Further, in this embodiment, when the coil spring 9 is arranged in a beam shape by cantilever support, the conductive pin 4 is connected to one end via the spring seat 8 and the coil spring 9 is connected to the other end. In constructing this type of drop sensor 1, it is desirable that the conductive pin 4, the spring seat 8 and the coil spring 9 be linearly connected on the horizontal central axis, and in particular, as the thickness and size become smaller, the coil The gap between the spring 9 and the container 2 is very small, and the axial center accuracy of the incorporated coil spring 9 is important in order to obtain a stable switching operation as the movable electrode 5 regardless of the mounting angle (360 degrees). It is. Moreover, since the coil spring 9 is in its coil form, the coil spring 9 is flexible and easily bent, and it is not always easy to match the central axes when connecting and fixing via the spring seat 8.

  However, according to this embodiment, the axis can be easily adjusted, and the required assembly accuracy can be ensured. Hereinafter, a means for adjusting the movable electrode 5 to be linearly connected to the central axis will be described with reference to FIG. FIG. 5 shows an assembly structure comprising a conductive pin 4 hermetically inserted into the sealing member 3 and a coil spring 9 having a spring seat 8 and a spherical body 10 constituting the movable electrode 5. A structure before being assembled into the container 2 by press fitting is shown. 2A shows the assembly structure before adjustment, FIG. 2B shows the assembly structure after adjustment, and FIGS. 1A-1 and 1B-1 show the structure in a natural state. For example, FIGS. 2 (a) -2 and 2 (b) -2 are views of the component viewed from the direction of the arrow B as viewed from the free end side of the coil spring 9. FIG. .

  In such an assembly stage as a component, the axis of the component (indicated by the center line R0) is slightly shifted to the right as indicated by the reference symbol R1, as shown in FIG. As shown in FIG. 2A-2, the circular outer diameter portion of the coil spring 9 is in an eccentric position with respect to the circular sealing member 3, so Is easily visible. Therefore, as shown in FIG. 1B, an appropriate portion of the spring seat 8 is sandwiched by tweezers, for example, and is slightly bent in the direction of arrow E or F in the drawing in a direction to correct the inclination.

Then, confirming that the coil spring 9 has been adjusted to the center position as shown in FIG. 2B-2, it is possible to obtain the proper axial center arrangement of the movable electrode 5 by extending the axial center arrangement of the coil spring 9. it can. Although the spring seat 8 is welded to the conductive pin 4 as described above, the coil spring 9 connected and fixed to the tubular portion 8a of the spring seat 8 in a fitted state is a little of the spring seat 8. The above-mentioned axial center adjustment is sufficiently possible with the angular displacement of.
Such a fall sensor 1 finally assembled and assembled by press-fitting the adjusted structure into the container 2 has been limited to a total thickness of about 5 mm in the past. For example, the thickness can be reduced to about 1 mm and, of course, it can be put to practical use.

As described above, according to the above embodiment, the following effects can be obtained.
As the drop sensor 1, the container 2 as the fixed electrode and the coil spring 9 as the movable electrode 5 have a circular configuration, so that they can be easily installed in devices such as portable computers without being restricted by the mounting angle of 360 degrees. In addition to the original function of the drop sensor 1 that can be incorporated in a compact manner and can detect a falling state by a normal switching operation and take quick countermeasures, it has the following excellent features.

  First, since the spherical body 10 constituting the weight of the movable electrode 5 is provided inward of the coil spring 9, when the coil spring 9 undergoes extreme refraction deformation, the spherical body 10 has a resistance action to prevent the deformation, so-called coil. It acts effectively as a core member of the spring 9 and effectively functions to suppress large deformations such as buckling deformation and plastic deformation of the coil spring 9 at the time of a drop impact. Further, since the outer diameter portion of the coil spring 9 can be a substantially maximum outer diameter of the movable electrode 5, it is extremely advantageous for reducing the diameter and reducing the thickness. However, the spherical body 10 has a smaller diameter than the inner diameter of the cylindrical coil spring 9 and further shortens the entire length L1 of the spherical body 10 in the free length direction so that the inside of the coil spring 9 is mainly free length. Since it is provided so as to be easily movable with respect to the direction, the coil spring 9 does not obstruct the elastic deformation as the movable electrode 5 at all.

  Further, in this embodiment, since the weight is configured as a sphere 10 made of a plurality of steel balls, the sphere 10 can be easily spheroidized by forging and can be provided at a low manufacturing cost. By adopting the sphere, the necessary number of spheres 10 as weights corresponding to the design specifications of the coil spring 9 can be prepared, which is advantageous for adjusting and setting an appropriate weight that requires accuracy.

  Moreover, as a means for preventing the spherical body 10 housed in the coil spring 9 from being removed, the free end portion of the coil spring 9 is used as a tapered winding portion 9b to completely block the opening or to reduce the diameter, and so on. By doing so, it can be securely stored and held in a retaining state. In this way, the coil spring 9 itself can be used to prevent it from coming off, so that no other parts or fixing means are required, and the movable electrode 5 can be simply operated by simply joining the base end portion 9a of the coil spring 9. Therefore, it is excellent in assembling property with high accuracy and more advantageous in cost. In addition, since the base end portion 9a is a tightly wound portion, sufficient bonding strength by an adhesive can be obtained, and it can withstand strength even when subjected to a large impact such as dropping, and the coil spring 9 can be easily seated. It is also effective in preventing bending deformation.

  Further, since the movable electrode 5 is composed of a coil spring 9 containing a movable sphere 10, the impact is applied when it collides with the container 2 as a fixed electrode as disclosed based on FIG. Damping effect can be expected to be received as a buffer. That is, the collision with the container 2 was conventionally a weight, but in the present embodiment, the coil spring 9 is interposed, so that a silencing effect can be expected inherently, and the tip of the coil spring 9 is the tip of the container 2. Even if the middle part remains in contact with the inner surface or is maintained in such a tendency, the intermediate part will swing, and even if the impact at the time of falling is buffered and bound, it can be suppressed to a small number of times and it will bounce at a minute distance Therefore, noise due to the collision sound can be effectively reduced. Therefore, the chattering phenomenon of the switching function due to the repeated contact / separation operation between the electrodes can be improved, and for example, the possibility of erroneous operation due to the “OFF” operation can be avoided.

  The collision sound between the coil spring 9 between the electrodes and the container 2 is not limited to being dropped, and may be generated as an unnatural noise even when being carried by a portable computer or the like that is a device incorporating the same. Therefore, also in this case, the effect of the damping action is effective and the commercial value can be increased. Further, in this embodiment, the taper winding portion 9b at the free end of the coil spring 9 is closely wound and is in contact with the container 2, so that it can sufficiently withstand even when repeatedly subjected to a collision action during a drop impact. Needless to say, the collision sound in this case is also extremely small due to the same buffering action as described above.

  Also, the coil spring 9 tends to concentrate bending stress in the vicinity of the joint portion of the base end portion 9a due to the dropping action or the above-described damping action as well as the stationary state. In addition to the rich characteristics, the tightly wound structure is connected and fixed to the conductive pin 4 via the spring seat 8, so that stress can be diffused without concentrating on one point, and buckling deformation is unlikely to occur. Therefore, the switching operation of contacting and separating the coil spring 9 and the inner surface of the container 2 as the movable electrode 5 can be maintained in a long-term stable state and the reliability can be improved.

  However, the damping effect is mainly the vertical expansion and contraction of the coil spring 9, whereas the wiping effect effectively utilizes the longitudinal expansion and contraction action as disclosed based on FIG. That is, since the free end portion of the coil spring 9 is in contact with the inner surface of the container 2 and slides to the left and right, dirt and oxide film on the contact surfaces can be removed. This is effective in that a stable switching operation can be obtained for a long period of time, and in particular, the concern about unstable operation due to the decrease in contact pressure between the electrodes can be eliminated in miniaturization.

  Further, in order to make the drop sensor 1 small and particularly thin, the gap around the coil spring 9 constituting the movable electrode 5 in the container 2 has a minimum design specification. For example, the thickness is 1.7 mm or less. 0. Since the gap is as small as several millimeters, the coupling and fixing of the coil spring 9 to the conductive pin 4 requires assembly accuracy for linear connection on a horizontal central axis. However, there is no functional problem even if the movable electrode is formed by connecting and fixing the coil spring 9 directly to the conductive pin 4. However, it is desirable that the axial center of the coil spring 9 after fixing can be easily adjusted because workability is reduced when a highly accurate assembly operation is forced when the coil spring 9 is connected and fixed. However, in the present embodiment, since the conductive pin 4 and the coil spring 9 are connected via the spring seat 8, as disclosed based on FIG. The shaft center can be adjusted by a slight displacement of the spring seat 8 that is fixedly supported.

  Thus, since the axial center arrangement of the coil spring 9 and the movable electrode 5 can be accurately arranged, the coil spring 9 can be arranged in a narrow space in the container 2 due to thinning, and any direction of 360 degrees. Even if it is installed in a computer, it is possible to detect an accurate fall state. In this respect as well, the possibility of realizing a thin shape can be greatly increased, and further downsizing of a portable computer etc. It is very effective inside.

  In the above embodiment, the taper winding portion 9b whose opening diameter is sequentially reduced is formed as a means for preventing the spherical body 10 from coming off from the free end portion of the coil spring 9, but the invention is not limited to this. 6 to 10 show modifications of the above-described retaining means, and substantially the same parts as those of the above-described embodiment are denoted by the same reference numerals, description thereof is omitted, and different parts will be described.

<First Modification>
First, FIGS. 6 to 8 are views corresponding to FIGS. 1 to 3 showing a first modification of the present invention, and are substantially the same as those in the above embodiment except for the means for preventing the spherical body 10 from coming off from the coil spring 9. It is a configuration.
That is, in place of the tapered winding portion 9b of the above embodiment, the bent end 9c is formed by tightly winding the free end portion in a cylindrical shape and bending the inner end opening the end. It is set as the structure provided. Accordingly, the bent terminal 9c is also extended to a substantially central position that bisects the opening, so that the cylindrical opening has a sealing port shape and the sphere 10 does not come out of contact with the bent terminal 9c. Needless to say, the function as the original drop sensor and other functions and effects are the same as those in the above embodiment.

<Second Modification>
Next, FIG. 9 is a view corresponding to FIG. 1 showing a second modification of the present invention. This is a structure formed by applying a conductive adhesive 14 while each of the above embodiments uses the coil spring 9 itself as a means for preventing the weight from being processed. That is, the free end portion of the coil spring 9 has a close winding configuration as in the above embodiment, but is open with its cylindrical opening. And the conductive adhesive 14 is apply | coated so that this open end part may be sealed, and it hardens | cures as it is.

  As a result, the opening at the free end of the coil spring 9 is sealed by the adhesive 14 solidified in a film shape, and functions as a retainer for the spherical body 10 that is stored thereafter. By the way, according to the present invention which can be reduced in thickness, the inner diameter D2 of the coil spring 9 becomes a minimum size of about 1.0 mm, and therefore the adhesive 14 may be applied little. However, since it is this extremely small size, when applying the adhesive 14, it is estimated that a part of the adhesive 14 protrudes outside the coil spring 9, for example. However, in this embodiment, since the adhesive 14 employs a conductive adhesive, the electrical conduction state with the container 2 is not hindered. However, although there is an advantage of using a conductive adhesive as described above, the conductivity is not necessarily required, and it is not necessary to completely seal the cylindrical opening of the coil spring 9 with the adhesive 14.

<Third Modification>
FIG. 10 is a view corresponding to FIG. 1 showing a third modification of the present invention. This means uses the spring seat 8 to which the base end portion 9a of the coil spring 9 is connected and fixed in common as a means for preventing the weight from coming off, that is, is connected and fixed to the free end side of the coil spring 9. is there. That is, first, the coil spring 9 has a full-length cylindrical shape as in the second modified example, and has a configuration in which the proximal end portion 9a and the free end side are also opened in close winding. As in the case of connecting and fixing the base end portion 9a to the conductive spring seat 8, the base end portion 9a is fitted and connected to the cylindrical portion 8a even on the free end side, and this is fixed with a conductive adhesive. However, this embodiment is the same as the above embodiment except for the means for preventing the internal sphere 10 from coming off. Here, the spherical body 10 as the weight employs two types of steel balls of different diameters. For example, a large-diameter large sphere 10a with two pieces on the free end side as a weight is accommodated, and the base end 9a side is accommodated. Three lighter diameter balls 10b that are lighter than this are housed.

  In this case as well, the common spring seat 8 is provided in addition to the function of the spherical body 10 as a shaft core structure of the coil spring 9 when the ball 10 is dropped and impacted, so that extreme refraction deformation of the coil spring 9 can be suppressed. It can be used as a means for preventing the sphere 10 from being removed simply by making the arrangement opposite to each other, and so-called new parts do not increase. In addition, since it is possible to unitize the spherical body 10 so as to prevent it from coming off, handling in storage or transfer work becomes easy. For example, the unitized one may be welded and connected to the conductive pin 4. This makes it possible to obtain a configuration that is versatile in assembly.

Further, the metal spring seat 8 provided on the free end side receives the gravity of the sphere 10 as a weight and directly contacts the container 2, but the contact by the elastic coil spring itself described in the above-described embodiments or the like, or Compared to a form such as contact via a conductive adhesive, the contact state by the rigid body is very good, and is excellent in that it functions stably as a movable contact of the so-called movable electrode 5 for a long period of time. In addition, in this embodiment, since the spherical sphere 10 serving as the weight is a large-diameter sphere 10a in which two of the five spheres 10 are heavy, and this is housed and arranged on the free end side of the coil spring 9, the container 2 is used as the movable electrode 5. The contact state with can be maintained more reliably.
The spheres 10 having different weight configurations are not limited to the size of the diameter. For example, the weight of the sphere 10 may be obtained by using the same diameter, and the number of the spheres 10 is naturally the design specification of the coil spring 9 or the like. Needless to say, it may be set appropriately according to the above, and can be widely deployed and implemented.

(Second Embodiment)
FIG. 11 is a view corresponding to FIG. 1 showing a second embodiment of the present invention. The same reference numerals are given to the substantially same parts as those of the first embodiment, and the description thereof will be omitted. Only different parts will be described.
In this embodiment, each of the above embodiments has a configuration including the sphere 10 as a weight, but the use of a sphere 15 made of a lightweight material such as plastic or aluminum, and another member also serving as a weight. The structure of the movable electrode 17 comprising the retaining member 16 made of is characterized.

  That is, the sphere 15 functions as an axial core component of the coil spring 9 but does not function as a weight. Therefore, a separate retaining member 16 is attached to the free end of the coil spring 9 as a means for retaining the spherical body 15, and the retaining member 16 is formed of a conductive member that is heavy. However, the retaining member 16 has a cylindrical shape as a whole, a small diameter portion 16a is formed in a stepped shape at one end, and the closely wound free end portion where the coil spring 9 is opened is formed in the small diameter portion 16a. The configuration is such that they are fitted and connected and fixed with a conductive adhesive. The outer diameter of the retaining member 16 is slightly larger than the outer diameter of the coil spring 9, but the required weight is not limited to the diameter, and can be easily set by adjusting the length.

  According to such a configuration, the same effects as those of the first embodiment can be obtained, and the weight can be provided with a simple configuration because of the configuration that also serves as the retaining member 16. Further, since the weight of the weight can be adjusted by the single retaining member 16, the weight can be easily set as compared with the plurality of weighted spheres 10 as in the above embodiment. Further, the retaining member 16 also functions as a contact point of the movable electrode 17 that contacts the container 2, and provides a more reliable contact state than the first embodiment in which the coil spring 10 contacts, and functions stably for a long time. Excellent in terms.

  However, since the retaining member 16 is also used as a weight, it may be slightly larger and the length dimension may be increased. However, since the sphere 15 in this embodiment does not need a function as a weight, the number of parts can be reduced and the diameter dimension can be reduced. It can be suppressed by adjusting it together with the coil spring 9 such as reducing the length, and this length dimension can be sufficiently achieved without any particular hindrance to the compactness due to the thinning that is particularly required. In the present embodiment, the retaining member 16 also serves as a weight. However, the present invention is not limited to this. For example, a dedicated retaining member and a weight may be prepared and incorporated.

  The present invention is not limited to the embodiments described above and shown in the drawings. For example, the shape of a spring seat for connecting and fixing the proximal end of the coil spring, or the weight retaining means for the free end of the coil spring. Various shapes can be developed without being limited to the structure of the above-described embodiment, and it is advantageous in strength to make the base end portion and the free end portion a close winding configuration, but this is provided if necessary. That's fine. In addition, the number of spheres as weights is not limited to five, and one or two spheres are possible, and not only steel balls, but also weight adjustment with spheres made of materials with different masses or combinations thereof. For example, there are options by various combinations so that the gravity is increased toward the free end side, and fine adjustment is also possible. Furthermore, the spherical body can be variously modified without departing from the gist of the present invention in practice, such as various configurations in which a weight is provided as a separate member as a function of protecting the coil spring from impact as an axis of the coil spring. It can be implemented.

Sectional drawing of the whole structure which shows 1st Example of this invention 1 equivalent diagram showing different states Sectional drawing cut | disconnected and shown along the AA line in FIG. Schematic configuration diagram for explaining the operation of different modes (a), (b), and (c) Configuration diagram for explaining operation of modes (a) and (b) before and after assembly adjustment FIG. 1 equivalent view showing a first modification 2 equivalent diagram FIG. 3 is a cross-sectional view corresponding to FIG. 3, taken along line GG in FIG. 7. FIG. 1 equivalent view showing a second modification FIG. 1 equivalent view showing a third modification FIG. 1 equivalent view showing a second embodiment of the present invention.

Explanation of symbols

  In the drawings, 1 is a drop sensor, 2 is a container (fixed electrode), 3 is a sealing member, 4 is a conductive pin, 5 and 17 are movable electrodes, 8 is a spring seat, 9 is a coil spring, 9a is a base end, 9b Is a tapered winding part, 9c is a bending terminal, 10 is a sphere (weight), 14 is an adhesive, 15 is a sphere, and 16 is a retaining member (weight).

Claims (8)

In a drop sensor formed by sealing a movable electrode in a conductive container,
The movable electrode includes a coil spring whose base end is connected and fixed to the end of a conductive pin inserted into the container and is cantilevered, and is movable inward of the coil spring and stored in a retaining state. A drop sensor characterized by comprising a weight.   The fall sensor according to claim 1, wherein the weight is a sphere having a diameter smaller than that of the coil spring.   The fall sensor according to claim 1 or 2, wherein the weight has a plurality of spheres.   4. The drop sensor according to claim 1, wherein the weight is shorter than the free length of the coil spring. In a drop sensor formed by sealing a movable electrode in a conductive container,
The movable electrode includes a coil spring whose base end is connected and fixed to the end of a conductive pin inserted into the container and is cantilevered, and is movable inward of the coil spring and stored in a retaining state. A drop sensor characterized by comprising a spherical body and a weight provided at the free end of the coil spring.   6. The drop sensor according to claim 5, wherein the weight is configured to also serve as a spherical retaining member.   The drop sensor according to claim 5 or 6, wherein the sphere has a plurality of configurations. The drop sensor according to any one of claims 5 to 7, wherein the sphere is configured to be shorter than a free length of the coil spring.

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