WO2002091604A2

WO2002091604A2 - Hinge device

Info

Publication number: WO2002091604A2
Application number: PCT/KR2002/000811
Authority: WO
Inventors: Young-Soo Han
Original assignee: Phoenix Korea Co., Ltd.
Priority date: 2001-05-03
Filing date: 2002-04-30
Publication date: 2002-11-14
Also published as: WO2002091604A3; AU2002251591A1; KR100473825B1; KR20020084689A; AU2002251591A8

Abstract

A radiotelephone includes a first unit, second unit and third unit with a camera. A hinge device couples the third unit to the first unit to rotate about an axis with respect to the first unit. The hinge device includes a case, a first rotary member, a linear movable member, a resilient member, a second rotary member and a support member. The case has a stopping wall. The first rotary member rotates about the axis with respect to the case and is coupled to the second unit. The linear movable member moves linearly along the axis by interaction with the first rotary member. The resilient member pushes the linear movable member toward the first rotary member. The second rotary member rotates about the axis with respect to the case and is coupled to the third unit. The second rotary member is pushed toward the wall.

Description

HINGE DEVICE

Technical Field

The present invention relates to a hinge device, and more particularly, to a hinge device capable of coupling one unit to another unit, for use in an apparatus in which the one unit is selectively rotatable with respect to the another unit, e.g. a potable radiotelephone having two case units and a camera.

Background Art

A portable apparatus, such as a portable folder-type radiotelephone, includes a keypad having a plurality of keys and a liquid crystal display. In the folder-type radiotelephone, the keypad is generally provided in one case unit while the liquid crystal display is provided in another case unit. When the radiotelephone is not in use, the radiotelephone is folded in a state where the keypad and the liquid crystal display face each other. When the radiotelephone is in use, it is unfolded. It is a hinge device that connects the two case units and allows smooth folding and unfolding of the radiotelephone. Meanwhile, functions of the radiotelephone are diversified. Particularly, such diversification of the functions is markedly increased in a radiotelephone meeting next- generation standards. For example, in a case of the radiotelephone meeting next- generation standards such as IMT 2000, a camera for video communication can be installed in the radiotelephone. In this regard, the portable apparatus such as the radiotelephone is required to perform the various functions. Such various functions are provided by various kinds of units.

However, although a conventional hinge device generally couples two units and allows relative rotation therebetween, it cannot provide organic connections of various devices for the units through which the various devices can sufficiently perform their functions. Summary of the Invention

The present invention is conceived to solve the problems in the prior art. It is an object of the present invention to provide a hinge device capable of coupling a plurality of units in an organic manner, and more specifically, a hinge device capable of coupling three units so that the units can rotate relatively to one another.

It is another object of the present invention to provide a hinge device wherein hinge shafts operable independently are provided at both sides of the device so that two units (e.g., one of case units of a radiotelephone and a camera unit) can rotate with respect to one unit (e.g., the other of the case units of the radiotelephone).

According to one aspect of the present invention, there is provided a hinge device for use in an apparatus having first, second and third units, for coupling the three units with one another such that the second and third units can independently rotate relatively to the first unit about an axis, comprising a case that is coupled to the first unit and has a stopping wall with a hole formed therein; a first rotary member that is rotatable about the axis with respect to the case and coupled to the second unit; a linear movable member that moves linearly within the case along the axis by interaction with the first rotary member; a resilient member for urging the linear movable member toward the first rotary member; a second rotary member that is rotatable about the axis with respect to the case, urged toward the stopping wall of the case to come into contact with the stopping wall, and coupled to the third unit through the hole of the stopping wall; and a support member that is interposed between the second rotary member and the resilient member and urged by the resilient member. Preferably, the hinge device further comprises a central shaft. The central shaft includes a head caught by the stopping wall, and a column extending from the head along the axis to pass through the hole of the stopping wall and to be coupled with the first rotary member through the- second rotary member, the support member, the resilient member and the linear movable member in such a manner that the column is coupled with the second rotary member to rotate together therewith but is coupled with the first rotary member to rotate relatively to each other. Further, a tip of the column of the central shaft is provided with a locking portion having an enlarged outer diameter and a tapered portion of which diameter is reduced forward, and the first rotary member is provided with a coupling wall that is formed in a hole of the first rotary member extending the axis, extends from an inner surface of the hole toward the axis and has an end hole having a diameter smaller than the enlarged outer diameter of the locking portion. Preferably, the coupling wall substantially takes the shape of a truncated cone. The support member may include a support plate that comes into contact with the resilient member, and a support rim depending from the support plate. The support plate is preferably urged by the resilient member and then deformed so that the support rim comes into contact with the stopping wall of the case.

A wave washer having alternating convex and concave portions along a circumference thereof may be interposed between the support member and the second rotary member. In a preferred embodiment, one of the rotary member and the linear movable member is provided with a cam, and the other is provided with a cam follower cooperating with the cam. The cam includes two peaks, which are symmetric to each other with respect to the axis, and valleys disposed between the peaks, a cam surface is formed by connecting the peaks and the valleys, and the cam follower may include projections that move along the cam surface and are positioned diametrically with respect to the axis.

According to another aspect of the present invention, there is provided a hinge device for use in an apparatus having first, second and third units, for coupling the three units with one another such that the second and third units can independently rotate relatively to the first unit about an axis, comprising a case that is coupled to the first unit and has a stopping wall; a first rotary member that is rotatable about the axis with respect to the case and coupled to the second unit; a second rotary member that is rotatable about the axis with respect to the case, urged toward the stopping wall of the case to come into contact with the stopping wall, and coupled to the third unit; and an urging member for urging the second rotary member toward the stopping wall. In a preferred embodiment, the case further includes a second stopping wall disposed on a side opposite to the stopping wall, the second stopping wall is in contact with the first rotary member, and the urging member urges the first rotary member.

According to a further aspect of the present invention, there is provided a hinge device for use in an apparatus having first, second and third units, for coupling the three units with one another such that the first and third units can independently rotate relatively to the second unit, comprising a case coupled to the first unit; a first rotary member that is rotatable with respect to the case and coupled to the second unit; and a second rotary member that is rotatable with respect to the case and coupled to the third unit.

According to a still further aspect of the present invention, there is provided a radiotelephone including a fist unit, a rotatable second unit coupled to the first unit, and a third unit mounted with a camera and coupled with the first unit. The radiotelephone further comprises any one of the aforementioned hinge devices for coupling the first, second and third units to one another.

Brief Description of the Drawings

FIG. 1 A is a perspective view showing a folder-type radiotelephone having two case units and a camera device connected with one another according to an embodiment of the present invention.

FIG. IB is a partial sectional front view of a connection portion of the folder- type radiotelephone of FIG. 1A, specifically showing a portion in which a hinge device according to one embodiment of the present invention is installed. FIG. 2 is a sectional view of the hinge device of FIG. IB, showing a case of the hinge device in section.

FIG. 3 is a view showing the case of the hinge device of FIG. IB. FIG. 4 is a view showing a rotary friction member of the hinge device of FIG. IB. FIG. 5 is a view showing a support member of the hinge device of FIG. IB. FIG. 6 is a view showing a support member according to another embodiment applicable to the hinge device of FIG. IB.

FIG. 7 is a view showing a cam member of the hinge device of FIG. IB.

FIG. 8 is a view showing a cam follower member of the hinge device of FIG. IB.

FIG. 9 is a view showing a fixing cap of FIG. IB.

FIG. 10 is a perspective view showing a hinge device according to another embodiment applicable to the folder-type radiotelephone of FIG. 1A.

FIG. 11 is an exploded perspective view of the hinge device of FIG. 10. FIG. 12 is a partial cut-away view of the hinge device of FIG. 10, showing the interior of the hinge device.

FIG. 13 is a sectional view showing a state of the rotary friction member and the support member before assembly of the hinge device of FIG. 10.

FIGS. 14 (a), (b) and (c) are views sequentially showing an operation of the hinge device of FIG. 10.

FIG. 15 is a sectional view showing a positional relationship between the cam member and the cam follower member of the hinge device of FIG. 10.

FIG. 16 is a sectional view of a hinge device according to a further embodiment of the present invention. FIG. 17 is a perspective view of a wave washer for use in the hinge device of

FIG. 16.

Detailed Description of the Embodiments

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Referring to FIGS. 1A and IB, a folder-type portable radiotelephone 10 having a camera mounted therein includes a first case unit 11 and a second case unit 12. A speaker and a liquid crystal display are housed in the first case unit 11. Generally, a keypad, a microphone, radio signal processing circuits and the like are housed in the second case unit 12. A camera unit 13 is rotatably coupled to the first case unit 11.

The camera 13 is positioned on a rotational axis of the two case units. A hinge device

14 couples the first and second case units 11, 12 and the camera.

Referring again to FIGS. 1A and IB, a mounting bore for the hinge device 14 is formed in an extension at a side of the first case unit 11. The hinge device 14 is fitted into and secured in the mounting bore. The mounting bore is shaped to correspond to the shape of a case 24 of the hinge device to be explained later. Thus, the hinge device

14 is fixed not to rotate with respect to the first case unit 11. The second case unit 12 is also provided with an installation hole. The installation hole is made slightly larger than the case 24 of the hinge device 14 to ensure easy insertion of the hinge device 14.

When the hinge device 14 is assembled with the case units 11, 12 and the camera 13, the hinge device can pass through the installation hole of the second case unit 12.

The hinge device 14 is inserted through the installation hole of the second case unit 12 and then secured in the first case unit 11. Subsequently, a fixing cap 15 is fitted into the installation hole so that the hinge device 14 is not exposed to the outside.

The fixing cap 15 is fixed to a first hinge shaft 16 disposed at a first hinge portion of the hinge device 14 as well as to the second case unit. As a result, the first hinge shaft 16 can be allowed to rotate together with the second case unit 12.

Meanwhile, the camera 13 having a lens 13d is fixed to a second hinge shaft 20a disposed at a second hinge portion of the hinge device 14. The camera 13 has an adjusting knob 13a for facilitating adjustment of an orientation of the camera 13. The adjusting knob 13a is fixed to the second hinge shaft.

Referring to FIG. 2, the hinge device according to an embodiment of the present invention comprises a case 24, a rotary friction member 20 and a friction support member 22 accommodated in the case 24, a resilient member 30, a cam follower member 26, and a cam member 28. The rotary friction member 20 and the friction support member 22 form the second hinge portion, and the cam follower member 26 and the cam member 28 form the first hinge portion.

FIG. 3 (a) is a side view of a main body of the case 24, FIG. 3 (b) is a side view of a cover 24a of the case, and FIG. 3 (c) is a front view of the main body of the case, showing an open face of the main body. Referring to FIGS. 1A to 3, the case 24 is comprised of a generally rectangular elongated barrel with four chamfered corners. Three faces of the case 24 are formed of flat walls 24b. The flat walls 24b function to prevent rotation of the case when the case is fitted and assembled into the first case unit 11 of the radiotelephone. Moreover, as will be described later, the flat walls also serve to prevent the support member 22 and the cam member 28 accommodated in the case from rotating. The remaining face of the case 24 is open. Various members are inserted and assembled into the case through the open face. The case 24 includes the cover 24a. After the various members are inserted into the case 24, the cover 24a covers the open face of the case and then is fixed thereto. Although not shown in detail in the figure, it will be understood by those skilled in the art that the cover 24a can be fastened to the main body of the case by means of various fastening methods such as snap-fit. There are end walls 36a, 36b with shaft holes 34a, 34b formed therein at both ends of the case 24. The case 24 is made of metal (e.g., brass plate). Alternatively, it may be formed by injection molding plastic resin.

FIG. 4 (a) is a left side view of the rotary friction member 20, FIG. 4 (b) is a front view thereof, and FIG. 4 (c) is a right side view thereof. Referring to FIGS. 1A and IB, and FIGS. 2 and 4, the rotary friction member 20 includes a disk 20a. A rectangular pillar type hinge shaft 20b protrudes from one side of the disk 20a. The hinge shaft 20b extends through a shaft hole 34a of the case 24. Two friction protrusions 20c protrude from the other side of the disk 20a. The friction protrusions 20c are generally hemispherical protrusions and disposed at positions symmetric with respect to a central axis. A cylinder 20d is formed at the center of the disk along the central axis. The cylinder 20d is fitted into a central hole 22a of the support member 22 to be explained later. The rotary friction member 20 can be made by injection molding the plastic resin.

FIG. 5 (a) is a side view of the support member 22, and FIG. 5 (b) is a longitudinal sectional view of the support member 22. Referring to FIGS. 1A and IB, and FIGS. 2 and 5, the support member 22 takes the shape of a generally rectangular plate with chamfered corners so as not to rotate within the case. The central hole 22a is formed in the center of the support member 22. The support member 22 can be made of a sheet of metal or plastic resin.

As well shown in FIG. 2, the resilient member 30 is a compression coil spring and urges the support member 22 toward the rotary friction member 20. Friction force is generated between the friction protrusions 20c and the support member 22. At this time, if a force having a magnitude larger than a predetermined value is applied to the knob 13a of the camera 13 to rotate the camera, the camera 13 is rotated. When the camera remains stationary, the camera 13 can be kept stationary by means of the friction force between the friction protrusions 20c and the support member 22 even though a certain degree of external force is applied thereto.

FIG. 6 (a) is a side view of a support member 22' according to another embodiment of the present invention, and FIG. 6 (b) is a longitudinal sectional view of the support member 22'. The support member 22' of FIG. 6 is substantially identical with that of FIG. 5 in their constitutions except that the support member 22' is provided with recesses 22b' into which the friction protrusions 20c are inserted. If the support member 22' is used, the friction protrusions are inserted into the recesses 22b' at a predetermined position. Therefore, the camera 13 can be kept in a more stable stationary state at this position rather than the other positions.

FIG. 7 (a) is a front view of the cam member 28, and FIG. 7 (b) is a side view of the cam member 28. Referring to FIGS. 1A and IB, and FIGS. 2 and 7, the cam member 28 is fitted into the case so that it can be linearly moved along the central axis therein but cannot be rotated, as shown in FIG. 2. To this end, the cam member 28 has flat walls 28a to correspond to the shape of the case. A cam 64 is formed on a side of the cam member opposite to the cam follower member 26. The cam 64 has a cam surface 66 provided on a side thereof facing the cam follower member. The cam 64 includes two peaks 68, 69 opposing diametrically with respect to a rotation axis 99, and two valleys 70, 71 separated by the peaks 68, 69 and opposing diametrically with respect to the rotation axis 99. The cam surface 66 consists of the peaks 68, 69, the valleys 70, 71 and a smooth curved surface connecting the peaks 68, 69 and the valleys 70, 71. The cam member 28 preferably has a cylindrical boss 76 extending the central rotation axis. The cam member 28 is provided with a through-hole 77 extending along the rotation axis. A central guide rod 55 formed on the cam follower member 26 is fitted into the through-hole 77 to cause a relative movement between the cam follower member 26 and cam member 28 to be guided. When the cam member 28 is assembled into the case 24, the cam surface is directed toward wings 56 of the cam follower member 26.

FIG. 8 (a) is a side view of the rotatable cam follower member 26 and FIG. 8 (b) is a front view thereof. Referring to FIGS. IB, 2 and 8, the cam follower member 26 includes a disk-shaped support 52, and the hinge shaft 16 extending along the rotation axis from a central portion of the support 52. The hinge shaft 16 is generally rectangular.

The central guide rod 55 protrudes from a side opposite to the side on which the hinge shaft 16 is formed. Two cam follower wings 56 are provided beside the central guide rod 55. The cam follower wings 56 extend together with the central guide rod

55 along the rotation axis to such a height that is shorter than that of the central guide rod 55. The two cam follower wings 56 are disposed to be symmetric to each other with respect to the rotation axis of the hinge device 14. The two wings 56 form a cam follower. The cam follower means a part for interacting with the aforementioned cam. Each cam follower wing 56 has a thickness reducing toward a tip end thereof and the tip end is rounded. It is apparent that the shape of the cam follower is not limited to that of the wing 56 and may be a post separate from the central guide rod.

The cam follower member 26 is inserted into the case 24 through the open face of the case. The cam follower member 26 can rotate about the rotation axis 99 within the case 24. As described above, the hinge shaft 16 of the cam follower member 26 protrudes through the shaft hole 34b of the case 24.

Referring to FIGS. IB and 2, the resilient member 30 urges the support member 22 toward the rotary friction member 20 and the cam member 28 toward the cam follower member 26, respectively. Referring still to FIGS. IB and 2, upon assembly of the hinge device, the rotary friction member 20 and the cam follower member 26 are first put into the case through the open face of the case 24. At this time, the hinge shafts 20b, 16 protrude through the shaft holes 34a, 34b, respectively. Subsequently, the support member 22 and the cam member 28 are put into the case so that they are positioned to face the rotary friction member 20 and the cam follower member 26, respectively. Finally, the resilient member 30 is inserted into the case in a maximally compressed state and then placed between the support member 22 and the cam member 28. Then, the restoring force of the resilient member 30 pushes the support member 22 toward the rotary friction member 20 and the cam member 28 toward the cam follower member 26, respectively. By covering the open face of the case with the cover 24a after the components are put into the case, the assembly is completed.

FIG. 9 (a) shows a side view of the fixing cap 15. The fixing cap 15 includes a head 15a and a body 15b. The body 15b extending from the head 15a takes the shape of a cylinder with both opposing sides thereof flattened. With flat surfaces 15c of the body formed in such a way, the fixing cap 15 is secured in the second case unit 12.

As can be seen from FIGS. 1A and IB, the installation hole of the second case unit 12 is formed to correspond to the body and head of the fixing cap. A coupling recess 15 d is formed at an end of the body 15b. The hinge shaft 16 is fixedly fitted into the coupling recess 15d. Therefore, the cam follower member 26, the fixing cap 15 and the second case unit 12 are coupled to one another and can be rotated as a unit.

The cam member, the cam follower member and the fixing cap are manufactured by injection molding plastic resin, preferably engineering plastic resin. Alternatively, they may be manufactured by means of powder metallurgy, forging, die casting or the like of metal. Hereinafter, the operation of the hinge device 14 of FIG. 2 will be described with reference to FIGS. IB and 2. FIG. IB shows an unfolded state where the first and second case units 11, 12 are moved away from each other, i.e. to an unfolded position of the radiotelephone. In the unfolded state, the cam follower wings 56 of the cam follower member 26 are placed in the valleys 70, 71 of the cam member 28. This state corresponds to a usable state. The camera 13 is activated for sending an image during telephonic communication in the unfolded state. If the orientation of the camera 13 is not proper, the rotatable knob 13a is turned. Then, the rotary friction member 20 is rotated. As described above, when the turning of the knob 13a is stopped, the camera is kept in the stationary state by means of the friction forces between the projections 20c and the support member 22 and between the rotary friction member and the case.

If the second case unit 12 is moved from the unfolded position to a folded position of the radiotelephone, the cam follower wings 56 of the cam follower member 26 move along the cam surface 66 and face the peaks 68, 69. At this time, the cam member 28 is pushed rearward and thus the spring is compressed. When the cam follower wings 56 pass over the peaks 68, 69, the cam follower wings 56 move down along the cam surface by means of the restoring force of the resilient member 30 so that the second case unit can be automatically moved to the folded position. In such a folded state, the cam follower wings 56 are finally positioned on slope portions of the cam surface.

The cam and cam follower of the first hinge portion can be constructed to have the same constitutions as cams and cam followers of cam members and cam follower members disclosed in Korean Patent No. 266516, Korean Laid-Open Patent Publication No. 1998-72158 and U.S. Patent No. 6,085,387 which were filed in the name of and/or issued to the present applicant. The descriptions in the specifications of the patent application or the patents are considered as being parts of the description of the present invention.

Meanwhile, it has been described in connection with the above embodiment that the second hinge portion is provided with the rotary friction member 20 and the support member 22, and the first hinge portion is provided with the cam member 28 and the cam follower member 26. However, both the first and second hinge portions may be otherwise provided only with a structure comprised of the rotary friction member and the support member. Alternatively, both the first and second hinge portions may be provided only with a structure comprised of the cam member and the cam follower member. Referring to FIGS. 10 to 12, a hinge device 110 according to another embodiment of the present invention has hinge shafts at both ends thereof, which are rotatable independently from each other. The hinge device 110 includes a rotary member 120, a linear movable member 150, a resilient member 180 comprised of a coil spring, a central shaft 170, a rotary friction member 220, and a friction support member

230. The rotary member 120, the linear movable member 150, the coil spring 180, the rotary friction member 220 and the stationary friction support member 230 are housed in case 190 of the hinge device 110 and coupled to one another by the central shaft 170. Referring still to FIGS. 10 to 12, the case 190 is comprised of a generally rectangular elongated barrel. A longitudinal centerline of the case 190 becomes a rotation axis 100 of the hinge device 110. The case 190 has an end wall or stopping wall 192 formed at one end thereof, and side walls 198 lengthily extending from the end wall 192. The other end of the case, which is opposite to the one end with the end wall 192 formed therein, is open. A central portion of the end wall 192 through which the rotation axis 100 passes is provided with a through-hole 190a (see FIG. 5). The central shaft 170 to be described later is inserted into the case 190 through the through-hole 190a. Corners where the four respective side walls 198 meet one another are chamfered. The four flat side walls serve as a key for preventing the case from rotating after the case is fitted and assembled into the case unit of the portable radiotelephone. Further, as will be described later, the flat side walls also serve to prevent the linear movable member 150 received in the case from rotating therein. The case 190 may be manufactured by injection molding plastic resin material or drawing sheet metal.

Referring to FIGS. 10 to 12, the rotary member 120 includes a disk-shaped base 121, a hinge shaft 122, and two cam follower protrusions 140 protruding from the base toward a side opposite to the hinge shaft 122. The rectangular pillar-type hinge shaft 122 has four side walls 125. The rotary member 120 is provided with a recess 127 formed by hollowing an end of the hinge shaft 122, and a coupling through-hole 129 connected with the recess 127 and formed along the rotation axis 100. As well shown in FIG. 12, a coupling portion 128 taking the shape of a truncated cone-type barrel around the rotation axis 100 is provided within the recess 127. The coupling portion 128 protrudes from the bottom of the recess 127 (or an inner surface of the through-hole 129). The coupling portion 128 has an inner diameter which is similar to that of the through-hole 129 at the bottom of the recess 127 but is reduced toward a tip end of the coupling portion. Although not shown in the figures, according to a further embodiment, a wall for forming the coupling portion 128 may be divided into forked wall segments with a plurality of radially extending gaps therebetween. The division of the wall into the forked wall segments is to facilitate insertion of the central shaft into the coupling portion. Referring again to FIGS. 11 and 12, the two identical cam follower protrusions

140 are disposed to be symmetric with respect to the rotation axis 100. Peaks 144 of the cam follower protrusions 140 mainly come into contact with a cam surface to be explained later. The through-hole 129 formed in the rotary member 120 is a circular hole into which the central shaft 170 to be explained in detail later is inserted to guide a rotational motion of the rotary member 120.

Referring still to FIGS. 11 and 12, the linear movable member 150 includes side walls 152, a cam 160 formed on a side of the linear movable member facing the rotary member 120, and a cylindrical boss 169 formed on a side of the linear movable member opposite to the cam 160. The linear movable member 150 is provided with a through-hole 151 penetrating from the cam 160 to the boss 169 along the rotation axis

100. The central shaft 170 to be described later is fitted into the through-hole 151 to guide a linear motion of the linear movable member 150. Corners where the side walls 152 for defining a rectangular pillar meet one another are chamfered. When the linear movable member is inserted into the case 190, the side walls 152 are snugly fitted into the case 190 so that the linear movable member can linearly move along but cannot rotate about the rotation axis 100 due to the interaction of the side walls 152 with the side walls of the case 190.

Referring to FIGS. 11, 14 and 15, the cam 160 includes a cam surface 162 on a side thereof facing the rotary member 120. The cam 160 is provided with two opposing peaks 164a, 164b symmetric to each other with respect to the rotation axis 100, and two opposing valleys 166a, 166b symmetric to each other with respect to the rotation axis 100. A relatively gentle slope surface 165 and a steep slope surface 651 are provided between the peak 164a and the valleys 166b, 166a, respectively. Further, a steep slope surface 641 is provided between the peak 164a and the valley 166b. A relatively gentle slope surface 642 is also provided between the peak 164b and the valley 166a.

Referring to FIGS. 10 to 12, the central shaft 170 includes a head 179 serving as the hinge shaft at the exterior of the case, and a column connected with the head. The column comprises an enlarged-diameter portion 171, an intermediate-diameter portion 173 connected with and lengthily extending from the enlarged-diameter portion

171, and a reduced-diameter portion 175 connected with an end of the intermediate- diameter portion 173. The enlarged-diameter portion 171 is provided with two flat portions 172 at positions symmetric to each other with respect to the rotation axis 100. An outer diameter of the cylindrical intermediate-diameter portion 173 is sized to be slidably fitted into the through-hole 129 of the rotary member 120 and the through-hole

151 of the linear movable member 150. A locking portion 751 is provided with the reduced-diameter portion 175 at the end thereof. An outer diameter of the reduced- diameter portion 175 is sized to be inserted into a hole at the tip end of the coupling portion 128 of the rotary member 120. Preferably, a maximum outer diameter of a locking portion 751 is larger than the outer diameter of the reduced-diameter portion

175, it is larger than an inner diameter of the hole at the tip end of the coupling portion

128 and it is slightly larger than an outer diameter of the tip end of the coupling portion

128. The locking portion 751 takes the shape of a truncated cone having a tapered tip.

Referring to FIGS. 11 and 12, the rotary friction member 220 is disk-shaped and one side thereof comes into contact with an inner surface of the end wall 192 of the case 190. The other side of the rotary friction member is provided with hemispherical protrusions 222 at axially symmetric opposing positions (see FIG. 12). A hole 224 is formed in the center of the rotary friction member. The hole 224 has arc portions 224a and linear portions 224b which are opposite to each other, respectively, to conform to the enlarged-diameter portion 171 of the central shaft 170. Therefore, the enlarged- diameter portion 171 is tightly fitted into the hole 224 so that the rotary friction member 220 rotates together with the central shaft 170.

The support member 230 has a support plate 232 for providing the friction force and pressing force. The support plate 232 generally takes the shape of a rectangle and is shaped to substantially conform to the cross section of the case 190 by chamfering corners of the rectangle. Thus, the support plate is prevented from rotating within the case 190. The support plate 232 is provided with a through-hole 233 having an inner diameter enough to allow the enlarged-diameter portion 171 of the central shaft 170 to freely rotate therein. The protrusions 222 come into contact with the support plate 232. A support rim 234 depends from the support plate 232. As well shown in FIG. 13, a height hi of the support rim 234 is lower than an overall height h2 of the rotary friction member 220. Therefore, the support rim 234 does not come into contact with the end wall 192 of the case 190 in a state where the force of the resilient member 180 is not exerted on the support member, as shown in FIG. 13. However, since the force of the spring 180 is exerted on an outer peripheral portion of the support plate 232 in an assembled state shown in FIG. 12, the support plate 232 is deformed so that the support rim 234 comes into contact with the end wall 192 of the case 190. In the assembled state, the support rim 234 is always kept to be in contact with the end wall 192 of the case 190. With such a constitution, even though the displacement of the spring 180 is changed by the operations of the rotary member 120 and the linear movable member

150, only a force resulting from the deformation of the support plate 232 is exerted on the rotary friction member 220. Accordingly, a rotational force capable of rotating the rotary friction member 220 always has a predetermined magnitude.

Referring still to FIGS. 11 and 12, upon assembly of the hinge device, the central shaft 170 is fitted into the case 190 through the central through-hole in the end wall 192 of the case 190 in such a manner that the locking portion 751 is inserted into the case 190. The head 179 of the central shaft 170 is caught by the end wall 192 of the case 190 and thus disposed at the exterior of the case. The head 179 also serves as the hinge shaft and subsequently is connected with the camera (see FIG. IB). First, the rotary friction member 220 is inserted into the case 190 so that the central hole 224 is fitted around the enlarged-diameter portion 171 of the central shaft 170 in a proper orientation. Then, the support member 230 is inserted into the case. Subsequently, the coil spring 180 is inserted into the case 190. At this time, the state shown in FIG. 13 is maintained. Then, the linear movable member 150 is inserted into the case 190 in such a manner that the boss 169 is directed toward the end wall 192 of the case 190 and fitted into and in contact with the coil spring 180. Here, the central shaft 170 penetrates through the through-hole 151 of the linear movable member 150. Finally, the rotary member is put into the case 190 and coupled to the central shaft 170. At this time, the rotary member is inserted into the case such that the cam follower protrusions 140 are directed toward the interior of the case 190 and come into contact with the linear movable member 150. When the rotary member 120 is inserted into the case, the tip of the central shaft 170 passes through the through-hole 129 of the rotary member 120. The locking portion 751 at the end of the central shaft 170 passes through the interior of the frustoconical coupling portion 128 of the rotary member 120 and is finally caught by the tip end of the coupling portion 128. This coupling is established in such a manner that the coupling portion 128 is slightly flared when the locking portion 751 of the central shaft 170 passes through the interior of the coupling portion 128 and restored when the locking portion 751 completely passes through the coupling portion beyond the tip end thereof. Consequently, the rotary member 120 is coupled to the central shaft 170 so as not to escape therefrom. The hinge device 110 can be easily assembled by forcibly pushing the rotary member 120 toward the central shaft 170 or the central shaft 170 toward the rotary member 120 in such a way. In the assembled state, the coil spring 180 is compressed and urges the linear movable member 150 toward the rotary member 120 and thence the support member 230 toward the rotary friction member 220.

The hinge device of FIG. 10 couples the first and second case units and the camera in the same manner as the hinge device shown in FIG. 2. The case 190 is fitted into and coupled to the second case unit. The hinge shaft 122 of the rotary member 120 is coupled to the first case unit. The generally rectangular head 179 of the central shaft 170 is coupled to the camera. Now, the operation of the hinge device 110 according to this embodiment will be described with reference to FIGS. 14 and 15. FIG. 14 (a) shows a state of the hinge device in the completely folded state of the radiotelephone where the second case unit is in contact with the first case unit. The position of the cam follower protrusion 140 on the cam surface 162 in this state of the hinge device corresponds to a position A shown in FIG. 15. In this state, the cam follower protrusion 140 is placed on the slope surface 651 between the peak 164a and the valley 166a on the cam surface 162. In this position A, the force of the coil spring 180 causes the cam member 150 to push the rotary member 120. At this time, the rotary member 120 is subjected to the rotational force by the coil spring 180 of the hinge device 110 and the slope surface 651. The rotational force causes the second case unit to come into close contact with the first case unit. As a result, the radiotelephone is stably maintained in the folded state.

When the case units are moved away from each other in order to unfold the radiotelephone from the folded state so as to utilize the radiotelephone, the cam follower protrusion 140 reaches the peak 164a of the cam surface 162. This state corresponds to FIG. 14 (b) and the position of the cam follower protrusion is a position B shown in FIG. 15. If the case units are further moved away from each other, the cam follower protrusion 140 passes over the peak 164a of the cam surface 162. When the cam follower protrusion 140 passes over the peak 164a of the cam surface 162, the cam follower protrusion 140 moves down along the slope surface 641 of the cam surface 162 without any external force since the coil spring 180 urges the cam member 150 toward the rotary member 120, and then, is inserted into and secured in the valley 166b. This state corresponds to FIG. 14 (c) and the position of the cam follower protrusion is a position C shown in FIG. 15. That is, the second case unit is in a state where the radiotelephone is completely unfolded. The process of switching the radiotelephone from the unfolded position to the folded position is made in reverse order of the above process. This can be easily understood by those skilled in the art with reference with the above description.

Meanwhile, since the spring 180 presses the outer peripheral portion of the support plate 232 of the support member 230, the support plate 232 is deformed. With the deformation of the support plate 232, the rotary friction member 220 is strongly pressed. If a rotational force having a magnitude larger than a predetermined value is exerted on the rotary friction member 220 in such a state, the rotary friction member 220 can be rotated. Therefore, if the orientation of the camera is intended to be adjusted in the unfolded (or folded) state of the radiotelephone, a force having a magnitude larger than the predetermined value should be exerted on the knob connected with the camera in order to rotate the camera. When the knob is rotated, the central shaft 170 of the hinge device 110 coupled to the knob is also rotated. The rotation of the central shaft 170 causes the rotation of the rotary friction member 220. If any force and thence rotational force is not exerted on the knob or an inadvertent small rotational force is exerted on the knob, the rotary friction member 220 is kept in the stationary state by means of the friction force.

FIGS. 16 and 17 show a hinge device 310 according to a further embodiment of the present invention. The hinge device 310 is identical with the hinge device 110 shown in IGS. 10 to 15 in their constitutions except for the constitutions of a rotary friction member 312, a support member 314 and a wave washer 316. The rotary friction member 312 takes the shape of a disk. The rotary friction member 312 is identical with that of the embodiment shown in FIGS. 10 to 15 in their constitutions except that the rotary friction member 312 does not have any protrusions. The support member 314 is identical with that of the embodiment shown in

FIGS. 10 to 15 in their shapes. However, the support plate 318 is not deformed contrary to that of the previous embodiment. The ring-type wave washer 316 is interposed between the support plate 318 and the rotary friction member 312. As well shown in FIG. 17, the wave washer 316 has alternating convex and concave portions formed along a circumference thereof. The wave washer 316 is interposed in a compressed state when it is inserted between the support plate 318 and the rotary friction member 312. Therefore, the wave washer 316 is in contact with the rotary friction member 312 and urges the rotary friction member 312 toward the end wall of the case 190. Although one wave washer is used in FIG. 17, two or more wave washers may be used in an overlapped state. When the hinge device according to the present invention is employed, three components (e.g., two case units and a camera) can be coupled to one another by using a single hinge device such that each of them can rotate relatively to the other components. If hinge members having different characteristics are disposed at both sides of the hinge device in the same way as the present invention, it is possible to ensure unique rotation functions of various units that require different rotation characteristics.

Although the present invention has been described in connection with the preferred embodiments, it is not limited thereto. It can be understood by those skilled in the art that modifications and changes can be made thereto without departing from the scope and spirit of the present invention, and that the present invention is intended to include these modifications and changes.

Claims

1. A hinge device for use in an apparatus having first, second and third units, said hinge device coupling the three units with one another such that the second and third units can independently rotate relatively to the first unit about an axis, comprising: a case that is coupled to the first unit and has a stopping wall with a hole formed therein; a first rotary member that is rotatable about the axis with respect to the case and coupled to the second unit; a linear movable member that moves linearly within the case along the axis by interaction with the first rotary member; a resilient member for urging the linear movable member toward the first rotary member; a second rotary member that is rotatable about the axis with respect to the case, urged toward the stopping wall of the case to come into contact with the stopping wall, and coupled to the third unit through the hole of the stopping wall; and a support member that is interposed between the second rotary member and the resilient member and urged by the resilient member.

2. The hinge device as claimed in claim 1, further comprising a central shaft, said central shaft including a head caught by the stopping wall, and a column extending from the head along the axis to pass through the hole of the stopping wall and to be coupled with the first rotary member through the second rotary member, the support member, the resilient member and the linear movable member in such a manner that the column is coupled with the second rotary member to rotate together therewith but is coupled with the first rotary member to rotate relatively to each other.

3. The hinge device as claimed in claim 2, wherein a tip of the column is provided with a locking portion having an enlarged outer diameter, and the first rotary member is provided with a coupling wall that is formed in a hole of the first rotary member extending along the axis, extends from an inner surface of the hole toward the axis and has an end hole having a diameter smaller than the enlarged outer diameter of the locking portion.

4. The hinge device as claimed in claim 3, wherein the coupling wall substantially takes the shape of a truncated cone.

5. The hinge device as claimed in claim 1 or 2, wherein the support member includes a support plate that comes into contact with the resilient member, and a support rim depending from the support plate.

6. The hinge device as claimed in claim 5, wherein the support plate is urged by the resilient member and then deformed so that the support rim comes into contact with the stopping wall of the case.

7. The hinge device as claimed in claim 5, wherein a wave washer having alternating convex and concave portions along a circumference thereof is interposed between the support member and the second rotary member.

8. The hinge device as claimed in claim 1, wherein the second rotary member has at least one protrusion protruding therefrom toward the support member to be in contact with the support member at a position spaced apart radially from the axis.

9. The hinge device as claimed in claim 1, wherein one of the rotary member and the linear movable member is provided with a cam, and the other is provided with a cam follower cooperating with the cam.

10. The hinge device as claimed in claim 8, wherein the cam includes two peaks, which are symmetric to each other with respect to the axis, and valleys disposed between the peaks, a cam surface is formed by connecting the peaks and the valleys, and the cam follower includes projections that move along the cam surface and are positioned diametrically with respect to the axis.

11. A hinge device for use in an apparatus having first, second and third units, said hinge device coupling the three units with one another such that the second and third units can independently rotate relatively to the first unit about an axis, comprising: a case that is coupled to the first unit and has a stopping wall; a first rotary member that is rotatable about the axis with respect to the case and coupled to the second unit; . a second rotary member that is rotatable about the axis with respect to the case, urged toward the stopping wall of the case to come into contact with the stopping wall, and coupled to the third unit; and an urging member for urging the second rotary member toward the stopping wall.

12. The hinge device as claimed in claim 10, wherein the case further includes a second stopping wall disposed on a side opposite to the stopping wall, the second stopping wall is in contact with the first rotary member, and the urging member urges the first rotary member.

13. A hinge device for use in an apparatus having first, second and third units, said hinge device coupling the three units with one another such that the first and third units can independently rotate relatively to the second unit, comprising: a case coupled to the first unit; a first rotary member that is rotatable with respect to the case and coupled to the second unit; and a second rotary member that is rotatable with respect to the case and coupled to the third unit.

14. An improved radiotelephone including a fist unit, a rotatable second unit coupled to the first unit, and a third unit mounted with a camera and coupled with the first unit, the improvement comprising: a hinge device for coupling the first, second and third units to one another claimed in any one of claims 1 to 12.