Camera mounting device

A camera-mounting device is provided that is inexpensive and resistive to vibration, and can generate a large coupling force with a small operation force. The camera-mounting device includes a ball shaft, a case main body provided with a ball-shaft receiver, a press plate that allows the ball shaft to be pressed onto the ball-shaft receiver and a cam that presses the press plate in a direction toward the ball shaft by a rotation of a lever, and in this structure, the rotation of the lever is made to have a multiplied force through the principle of the lever to push the press plate down so that the cam and a cam contact face are made in contact with each other on a flat face. With this arrangement, a large coupling force is generated by a small force so that the device is made resistive to vibration.

BACKGROUND OF THE INVENTION

(1) Field of the Invention

The present invention relates to a camera-mounting device that is used for attaching, for example, a monitor camera or the like to a ceiling above a front glass of a mobile body such as a car in a suspended state.

(2) Description of the Related Art

In a conventional camera-mounting device, securing and releasing mechanisms (mainly, screws) are placed near a rotation ball shaft so as to firmly secure a camera mounted on a—(for example, see Japanese Unexamined Patent Publication 10-288811).FIGS. 9 and 10show a conventional camera-mounting device described in the Patent Publication.

FIG. 9is an exploded perspective view showing one portion of a case main body, andFIG. 10is a longitudinal cross-sectional view. This camera-mounting device has a structure in which a mount base121having a truncated cone shape with a cone face122being formed on its upper portion is installed on the bottom of a cylindrical case main body101, and a belt-shaped tightening mechanism131having a handle141is placed on the upper portion of this mount base121. Moreover, a ball shaft111having a spherical shape is mounted on the upper portion of the tightening mechanism131. Cone faces132and133are formed on the upper and lower inner faces of the ring portion of the tightening mechanism131, and the cone face133on the lower side and the cone face122of the mount base121are made in contact with each other, with the ball shaft111having a spherical shape being mounted on the cone face132on the upper side. Here, the upper portion of the ball shaft111is made in contact with the inner face of the upper portion of the case main body101.

In the above-mentioned structure, when the handle141is rotated in a securing direction, the tightening mechanism131is tightened inward by functions of the handle141and the screw shaft142so that the ring portion of the tightening mechanism131is allowed to intrude between the ball shaft111and the mount base121. Since the ball shaft111, the tightening mechanism131and the mount base121are placed in the case main body101without any gap, the ball shaft111is raised by tilt vectors exerted on the cone faces132and133formed on the upper and lower ends of the tightening mechanism, the cone face122of the mount base121and the ball shaft111, so as to be firmly pressed onto the inner face of the upper portion of the case main body101so that the ball shaft111is secured onto the case main body101.

In the above-mentioned conventional structure, however, in the case of poor machining precision of parts, the ball shaft111fails to obtain a sufficient holding strength to the case main body101. For this reason, a special machining process is required for manufacturing the tilt face to cause the parts to become expensive. Moreover, since the securing and releasing operations for the ball shaft111are carried out by the screw shaft142of the handle141, the screw tends to become loose due to vibration when installed in a mobile body such as a vehicle, resulting in a problem of degradation in the securing force.

In order to solve these problems, the objective of the present invention is to provide a camera-mounting device that exerts a firm securing force, and is resistive to vibration.

SUMMARY OF THE INVENTION

In order to solve the above-mentioned conventional problems, the camera-mounting device of the present invention is provided with a ball shaft having a ball portion and a shaft portion, a case main body provided with a ball-shaft receiver that holds the ball portion of the ball shaft, a press plate that allows the ball shaft to be pressed onto the ball-shaft receiver and a cam that presses the press plate in a direction toward the ball shaft by a rotation of a lever, and in this structure, the cam has a first flat portion and a second flat portion that has a distance longer from the rotation center of the cam in comparison with the first flat portion, and when the first flat portion of the cam is allowed to press the press plate through the rotation of the lever, the press plate is not allowed to press the ball shaft, while, when the second flat portion of the cam is allowed to press the press plate through the rotation of the lever, the press plate is allowed to press the ball shaft so that the ball shaft is sandwiched between the ball-shaft receiver and the press plate to be secured between them.

In accordance with the camera-mounting device of the present invention, the rotation of the lever is made to have a multiplied force through the principle of the lever to push the press plate down so that the cam and a cam contact face are made in contact with each other on a flat portion; thus, a large coupling force is generated by a small force so that it becomes possible to achieve a firm securing operation that is resistive to vibration by using inexpensive parts, through one-hand operations.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to Figures, the following description will discuss preferred embodiments of the present invention. In these embodiments, explanations will be given by exemplifying a camera-mounting device used for securing a monitor camera for vehicles into a vehicle; however, the camera-mounting device of the present invention is not intended to be limited only by those devices used for vehicles, and may be used for trains, airplanes, ships and the like, as well as for such an application as to securing a camera to a pillar, a wall or the like in a building, and the application is not intended to be specifically limited to a narrow range.

First Embodiment

FIG. 1is a structural drawing (exploded perspective view) that shows parts of a camera-mounting device in accordance with a first embodiment of the present invention.

A casing of the main body portion of this camera-mounting device is constituted by a case main body211having a virtually elliptical shape and a lid member251that covers the upper portion of this case main body211so that the case main body211is covered with the lid member251, with a shallow housing space being prepared therein. The lid member215is secured to the case main body211with securing screws291. A ball shaft receiver212having a bowl shape is formed on the front portion of the case main body211so as to support the ball shaft201.

The ball shaft201is constituted by a ball portion203having a shape in which the top portion of a spherical body is cut off and a shaft portion204that extends downward from the bottom of the ball portion203. The ball shaft201is supported onto a ball shaft receiver212formed on the case main body211to be allowed to pivot thereon, with the ball portion203being pressed by a ball shaft pressing portion222located on the periphery of a round hole225of a press plate221from above, so that it is secured in the case main body211. Here, the top portion of the ball portion203is cut off so as to make the thickness of the casing thinner.

In the press plate221, the ring-shaped ball shaft pressing portion222having the round hole225as described above and a slanting portion226that extends rearward from the rear end edge of the ball shaft pressing portion222are allowed to protrude in a manner so as to tilt downward, with a cam-contact face223further sticking out from the slanting portion226horizontally. The cam-contact face223at the rear end of the press plate221is placed at a position to be made in contact with a cam231formed on a lever shaft241(hereinafter, referred to simply as a cam, and the cam will be described later in detail), and this cam-contact face223is pressed downward by the cam231. Moreover, a screw contact point224is formed at the tip portion of the press plate221, that is, at a position on the side opposing to the cam-contact face223with the ball shaft pressing portion222located in between. This contact point224is formed by a triangular member sticking out forward from the ball shaft pressing portion222, and this member serves as the contact point224. Moreover, reinforcing ribs227are formed on the two sides of the press plate221. In the present embodiment, the press plate221is formed through a single squeezing technique by using a stainless steel plate for springs.

The lever242is coupled to one end of the lever shaft241in which the cam231is formed with screws (not shown). The rotation of the lever242is transmitted to the cam231through the lever shaft241so that the cam231is allowed to rotate. The lever shaft241is sandwiched and supported by bearings213and253that are respectively formed by cutting the side edges of the case main body211and the lid member251into a semi-circular shape so as to be allowed to rotate thereon.

The lid member251is provided with an adjusting screw hole252at a position facing the screw contact point224, and an adjusting screw261is screwed therein. By the rotation of the adjusting screw261, the screw contact point224is pressed downward or slackened so that it is placed in a manner capable of shifting upward as well as downward.

An attaching member271is bent into a spoon shape with an attaching hole272being formed in the center of a round portion on the rear end portion. By using this attaching hole272, the member is secured to a car body by being co-fastened onto a sun visor hook (not shown). Moreover, the entire camera-mounting device is designed to be suspended by a securing screw281through a supporting pillar282having a truncated cone shape. Referring toFIG. 2, the following description will discuss functions of the camera-mounting device having the above-mentioned structure in the embodiment of the present invention.

FIG. 2is a cross-sectional view that shows a camera-mounting device in accordance with the first embodiment of the present invention, from which securing screws291and screw holes are omitted for convenience of explanation. InFIG. 2, two flat portions, that is, a first flat portion232and a second flat portion233, are formed on a cam231in a manner so as to form a blunt angle. The distance between the second flat portion233and the rotation center of the lever shaft241is made longer than the distance between the first flat portion232and the rotation center of the lever shaft241.

InFIG. 2, the cam231is located at a slackening position, with the cam231being made in contact with the cam contact face223at the first flat portion232. At this time, the press plate221is in a state in which it does not press the ball shaft201, that is, the pressing force is set to 0. For this reason, the ball shaft201, supported by the ball shaft receiver212, is not restrained in movements of the ball portion203by the ball shaft pressing portion222of the press plate221so that it is allowed to move with a predetermined angle. For this reason, it is possible to change the image-pickup angle of a camera301attached to the shaft portion204of the ball shaft201.

Next, when the lever242is made to pivot from the slackening position shown inFIG. 2to a tightening position in an arrow direction, the cam231is made in contact with the cam contact face223at the second flat portion233. Since the second flat portion233is farther from the rotation center of the lever shaft241in comparison with the first flat portion232, the cam231is allowed to have a doubled force through the principle of the lever, and presses the cam-contact face223of the press plate221downward.

The cam231has its cam-contact face223made in contact with any one of the flat portions, that is, the first flat portion232and the second flat portion233; therefore, upon contacting at a position other than the slackening position and the tightening position, the cam231is pushed back to any one of the positions by a repulsive force of the press plate221. For this reason, the lever242is allowed to be positioned only at the two positions, that is, the slackening position and the tightening position. Moreover, the repulsive force is applied to the cam231, with the cam contact face223being made in contact with the flat portion of the cam231, so that the layer242is restrained from its rotation, and prevented from being slackened by vibrations or the like of the car, which makes this structure different from a simple screw securing. The deformation and shifts of the contact member caused by the cam231, as well as the multiplied force by the lever function, are prior art techniques; therefore, the description thereof is omitted.

The press plate221, thus pushed down, has its contact point224at which it is made in contact with the adjusting screw261as a fulcrum, its cam-contact face223as a force application point and its ball shaft pressing portion222as an action point, and simultaneously as the ball shaft pressing portion222presses the ball portion203of the ball shaft201through the lever function, the ball shaft201is pressed onto the ball shaft receiver212so that the ball shaft201is firmly secured to the case main body211. In this first embodiment, by using a multiplied force of 1.8 times in the press plate221as well as by using a multiplied force of 9.3 times in the lever242and the cam231, a multiplied force of 16.7 times in total is used to carry out a securing process; thus, by using a light operation of the lever242, it becomes possible to achieve a firm securing operation. In this manner, the camera-mounting device of the present invention makes it possible to carry out slackening and tightening operations of the ball shaft201by switching the slackening position and the tightening position of the lever.

Here, by adjusting the up and down position of the adjusting screw261, as well as by changing the position at which the adjusting screw261is made in contact with the screw contact point224, the position of the fulcrum is changed so that the securing force to be applied when the lever242is placed at the tightening position can be adjusted.

Next, referring toFIG. 2, the following description will discuss that the present invention makes it possible to eliminate the necessity of high precision machining with respect to the parts. Even in the case when a deviation occurs in any of the diameter of the ball portion203of the ball shaft201, the diameter of the spherical face of the ball shaft receiver212and the diameter of the round hole225of the ball shaft pressing portion222, since the contact portion between the individual parts is formed by a spherical shape and a circle, by shifting the fulcrum with the adjusting screw261rotated, the cam contact face223and the position of the cam231can be easily corrected. Moreover, although the two positions of the slackening position and the tightening position are prepared in the present invention, it is possible to apply a pre-pressure to the press plate221by the adjusting screw261so that the ball shaft201may be made to have a slight frictional load at the slackening position. Moreover, in an attempt to prevent degradation in the holding force due to abrasion and deformation of parts caused by a long time use, the adjusting screw261may be slackened, and this may be returned to a firmly secured state by simply rotating the adjusting screw261.

FIG. 3shows another embodiment of the above-mentioned the first embodiment. In this embodiment, a rib214is formed on the bottom plate of the case main body211near the rear of the ball shaft201, and an elastic member215, made of rubber, sponge or the like, is formed at the upper end of this rib214. This elastic member215is allowed to raise the press plate221upward so that the ball shaft pressing portion222of the press plate221is prevented from contacting the ball portion203of the ball shaft201. Here, instead of rubber and sponge, the elastic member215may be formed by using a spring.

As shown inFIG. 2, even in a state in which the press plate221is not allowed to press the ball shaft201, that is, the pressing force is set to 0, the ball shaft201can be moved. However, the opening edge of the ball shaft pressing portion222tends to be meshed with the ball portion203of the ball shaft201to make it sometimes unmovable smoothly. For this reason, by providing the above-mentioned state in which the press plate221is raised by the elastic member215, a gap is formed between the opening edge of the ball shaft pressing portion222and the ball portion203of the ball shaft201in the slackening position of the lever242so that the ball shaft201is allowed to move smoothly.

Here, in the case when the lever242is pressed downward against the elastic force of the elastic member215, the ball shaft pressing portion222is allowed to press the ball portion203of the ball shaft201so that the ball shaft201is secured in the case main body211.

FIG. 4is a drawing that shows an applied state in which the lever242is being operated, with a monitor camera301being attached to a camera screw202of the ball shaft201of a camera-mounting device in accordance with the first embodiment of the present invention. In general, there are switches for operations, such as zooming of an image and starting of an image recording process, on the back face of a camera used for vehicles. In accordance with the present invention, since the lever operation point can be placed at a position that allows the user to operate the lever242by using a second finger upon grabbing the back face of the camera, it becomes possible to achieve a series of operations for aiming at an object, for securing the camera-mounting device and for starting an image pickup only by using one hand.

InFIGS. 1 and 2, the press plate221is formed through the single squeezing technique by using a stainless steel plate; however, this may be prepared as a molded product made through an injection molding process such as aluminum die casting, with the same effects, and needless to say, the ball shaft pressing portion222may be formed into a cone face or a spherical face with the same effects.

Second Embodiment

Referring to Figures, the following description will discuss a second embodiment of the present invention. In the present embodiment also, the description will be given by exemplifying a camera-mounting device used for securing a monitor camera for vehicles into a vehicle.

FIG. 5is a structural drawing (exploded perspective view) that shows parts of a camera-mounting device in accordance with the embodiment of the present invention. In the camera-mounting device in accordance with the second embodiment, with respect to the casing constituted by a case main body211and a lid member251, the press plate221provided with a screw contact point224, a ball shaft pressing portion222and a cam contact face223, the lever shaft241provided with a cam231and the lever242, as well as the attaching member271, the adjusting screw261and the like, the same members as the aforementioned the first embodiment are used; therefore, the same reference numerals are used, and detailed description thereof is omitted.

The present the second embodiment is different from the aforementioned the first embodiment in the ball shaft201. The ball shaft201is constituted by a ball portion203and a shaft portion204, and the ball portion203is integrally formed by a lower ball203acentered on a point A and an upper ball203bcentered on a point B. Although the upper ball203band the lower ball203ahave virtually the same diameter, the center point A of the lower ball203aand the center point B of the upper ball203bare located on the center axis line of the ball shaft201, and the center point B is positioned below the center point A. Of course, the upper ball203band the lower ball203amay have mutually different diameters. Moreover, the distance between the center point A and the center point B may be made wider than that shown inFIG. 1, or may be made narrower than that. Furthermore, the upper and lower positions of the center point A and the center point B may be mutually exchanged.

With respect to the ball shaft201, the lower ball203ais supported by a ball shaft receiver212formed in the case main body211so as to pivot thereon, and the ball portion203is secured to the case main body211, with the upper ball203bbeing pressed from above by the ball shaft pressing portion222of the press plate221.

The following description will discuss the applied state of the above-mentioned structure.

InFIG. 6, the cam231is located at a slackening position, with the cam231being made in contact with the cam contact face223at the first flat portion232. At this time, the press plate221is maintained in such a state as not to press the upper ball203bof the ball shaft201, that is, a state in which the pressing force is zero. For this reason, since the upper ball203bis not restrained in its movements by the ball shaft pressing portion222of the press plate221, the ball shaft201can be moved. Thus, the camera301, attached to the shaft portion204of the ball shaft201, is allowed to change its image pickup angle.

Next, when the lever shaft241is allowed to pivot from the slackening position shown inFIG. 6to a tightening position in an arrow direction, the cam231is made in contact with the cam contact face223at the second flat portion233. Since the second flat portion233is farther from the rotation center of the lever shaft241in comparison with the first flat portion232, the cam231is allowed to have a doubled force through the principle of the lever, and presses the cam-contact face223of the pressing member221downward.

The cam231has its cam-contact face223made in contact with any one of the flat portions, that is, the first flat portion232and the second flat portion233; therefore, upon contacting at a position other than the slackening position and the tightening position, the cam231is pushed back to any one of the positions by a repulsive force of the press plate221. For this reason, the lever242is allowed to be positioned only at the two positions, that is, the slackening position and the tightening position. Moreover, the repulsive force is applied to the cam231, with the cam contact face223being made in contact with the flat portion of the cam231, so that the layer shaft241is restrained in its rotation, and prevented from being slackened by vibrations or the like of the car, which makes this structure different from a simple screw fastening. This feature is the same as that obtained in the aforementioned the first embodiment.

The press plate221thus pushed down has its contact point224at which it is made in contact with the adjusting screw261as a fulcrum, its cam-contact face223as a force application point and its ball shaft pressing portion222as an action point, and simultaneously as the ball shaft pressing portion222presses the upper ball203b, the lower ball203aof the ball shaft201is pressed onto the ball shaft receiver212so that the ball shaft201is firmly secured to the case main body211. In the present embodiment, by using a multiplied force of 1.8 times in the pressing member as well as by using a multiplied force of 9.3 times in the lever242and the cam231, so that a multiplied force of 16.7 times in total is used to carry out a securing process; thus, by using a light operation of the lever242, the ball shaft201is firmly secured to the case main body211. In this manner, the camera-mounting device of the present invention makes it possible to carry out slackening and tightening operations of the ball shaft by switching the slackening position and the tightening position of the lever.

Additionally, by adjusting the upward and downward positions of the adjusting screw261so that the position at which the adjusting screw261is made in contact with the screw contact point224is changed, the position of the fulcrum is changed, and the securing force to be exerted upon placing the lever242at the tightening position can be adjusted.

Referring toFIGS. 7A and 7B, the following description will discuss the functions and effects of the ball shaft201having the ball portion203constituted by the lower ball203aand the upper ball203bwith mutually different center positions as described above.FIGS. 7A and 7Bare explanatory drawings for stresses, which indicate comparisons between the securing methods of a conventional ball shaft and the ball shaft of the present invention. Since the ball portion of the conventional ball shaft111has a complete spherical shape, the contact points between the ball portion and a mount base121as well as between the ball portion and the case main body101(seeFIGS. 9 and 10, only contact lines are indicated by broken lines) are located on a circle having a diameter of φ1(which is actually a spherical face, but indicated as a circle shown inFIG. 7Afor convenience of explanation). In the same manner as other portions on the surface of the ball portion, this circle is positioned with a radius R1from the center of the ball portion. Therefore, in response to rotation of the ball portion of the ball shaft111, this point is always located on the circle. In contrast, supposing that the point is rotated around the center point of the ball portion, the point on the circle is moved along the circle of the ball shaft111, with the result that no mechanically restraining force is exerted thereon except for friction. Consequently, the rotation moment, applied onto a camera screw, has been restrained only by friction caused by materials at the two contact portions having the diameter of φ1.

In contrast, with respect to the ball shaft201of the present invention, supposing that the ball shaft201is rotated in a direction of an arrow R centered on the point A, the lower ball203acentered on the point A is restrained only by friction with respect to the arc portion of the ball shaft receiver212(not shown inFIG. 7B, only contact lines are indicated by broken lines) in the same manner as the conventional ball shaft111. On the other hand, the center point of the upper ball203bcorresponds to point B that is a position different from that of the point A so that, since the contact circle between the upper ball203band the ball shaft pressing portion222of the press plate221(not shown inFIG. 7B, only contact lines are indicated by broken lines) is not present on the spherical face centered on the point A, at the contact point ofFIG. 7B, a vector of a force is generated in a pressing direction on the ball shaft pressing portion222due to a rotation moment applied to the camera screw202.

As shown in the partially enlarged drawing ofFIG. 7B, a contact point C is moved in a direction of a vector c by the rotation of the upper ball203bin the direction of the arrow R. When the vector c is divided into two vectors in the contact face direction and in a direction perpendicular thereto at the point C, respective vectors ch and cv are formed. Since the vector ch is a vector in the contact face direction of the upper ball203b, no pressing force is generated onto the ball shaft pressing portion222. Moreover, since the vector cv is also a vector in a departing direction from the ball shaft pressing portion222, no pressing force is generated in the same manner. In other words, at the contact point C, the ball shaft pressing portion222does not intervene with the rotation of the upper ball203b.

On the other hand, a contact point D is moved in a direction of a vector d by the rotation of the upper ball203bin the direction of the arrow R. When the vector d is divided into two vectors in the contact face direction and in a direction perpendicular thereto at the point D, respective vectors dh and dv are formed. Since the vector dh is a vector in the contact face direction of the upper ball203b, no pressing force is generated onto the ball shaft pressing portion222. However, since the vector dv is a vector in an approaching direction toward the ball shaft pressing portion222, a pressing force is generated.

Since this vector dv is exerted in such a direction as to make the upper ball203bof the ball shaft201meshed with the ball shaft pressing portion222, the rotation moment, applied to the camera screw202, is mechanically restrained in its rotation by the contact circle between the upper ball203band the ball shaft pressing portion222of the press plate221so that a firm securing operation is achieved. This effect can be easily verified by the fact that, even when oil or the like is applied to the ball portion203of the ball shaft201to reduce a frictional force, the rotation of the ball shaft201is restrained.

Here, inFIG. 6, the spherical centers of the lower ball203aand the upper ball203bare formed at positions at which straight lines extending toward the circumferences of the upper ball203band the lower ball203afrom points A and B are made to mutually intersect with each other; however, not limited to this structure, it is only necessary for the mutual centers not to be located at the same position, and needless to say, for example, a ball shaft having two balls whose spherical centers are separated from each other may be used with the same effects.

FIG. 8shows another embodiment relating to the above-mentioned the second embodiment. In this embodiment also, a rib214is formed on the bottom of the case main body, and an elastic member215is attached to the upper end of the rib214. Here, in this case also, instead of rubber and sponge, a spring may be used for the elastic member215. In the same manner as the other embodiment relating to the aforementioned the first embodiment, the elastic member215also raises the press plate221upward so that the opening edge of the ball shaft pressing portion222of the press plate221is prevented from contacting with the upper ball203bof the ball shaft. Thus, the ball shaft201is allowed to move smoothly.

In accordance with the camera-mounting device of the present invention, it becomes possible to achieve a firm securing operation that is resistive to vibration by using inexpensive parts, and also to allow one-hand operations; thus, the resulting device is effectively used as a camera-mounting device to be attached to mobile objects such as vehicles, which is free from degradation in the securing force due to vibration.