Opening/closing mechanism

Abstract: The invention relates to an opening/closing mechanism for being used in apparatus such as personal computers, word processors and liquid-crystal televisions. The opening/closing mechanism comprises a base (10) attached to a main body (20) of an apparatus; an arm (18) attached to an opening/closing portion (21) of the apparatus and axially supported on the base (10) so as to turn freely; a rotary plate (12, 13) which turnes together with the arm (18) and which has a projection (13d); a pop-up plate (14) having an engaging portion (14b, 14c), wherein when the opening/closing portion (21) is closed up to a prescribed position, the engaging portion (14c) engages with the projection (13d) of the rotary plate so that the pop-up plate turnes together with the rotary plate (13); and a resilient member (19) provided between the pop-up plate (14) and the base (10) and compressed by turning of the pop-up plate (14), wherein when the opening/closing portion (21) is released, the rotary plate (13) is turned together with the pop-up plate (14) by a compressive reaction force, thereby opening/closing portion (21) up to a prescribed position.

Description: Technical Field to which the Invention relates This invention relates to an opening/closing mechanism in an apparatus having a main body and an opening/closing portion. Background Art In apparatus such as personal computers, word processors and liquid-crystal televisions, some of these apparatus long available on the market have an opening/closing portion, such as a display panel folded onto a main body in order to make the apparatus portable. In order to make it easy to set upright the opening/closing portion, the arrangement is such that the opening/closing portion opens slightly when this portion is released. Further, it is so arranged that it is not possible to close the opening/closing portion completely unless this portion is pressed, when the opening/closing portion is closed. This arrangement prevents the opening/closing portion and the main body from striking. A conventional apparatus of this kind thus constructed employs an opening/closing mechanism shown in Fig. 11. A base 1 shown in Fig. 11 is attached to the main body of an apparatus. A shaft 2 is supported by the base 1 so as to turn freely. Further, the opening/closing portion of the apparatus, a cam 3, and a coil spring 4 are attached to the shaft 2. The shaft 2 and cam 3 rotate in the direction of arrow A when the opening/closing portion is opened, and in the direction of arrow B when the opening/closing portion is closed. When a projection 3a formed on the cam 3 is at a position where it abuts against an end portion 4a of the coil spring 4, as shown in Fig. 11, the opening/closing portion is in a slightly open state. If the opening/closing portion is now pushed to turn the shaft 2 and cam 3 further in the direction of arrow B, the coil spring 4 is urged. When the opening/closing portion is released under these conditions, the cam 3 is rotated in the direction of arrow A by the force of the coil spring 4 and comes to rest in the state shown in Fig. 11. In other words, the opening/closing portion pops up by opening slightly at this time. In general, a strong spring is necessary in order to raise an opening/closing portion such as the display portion of a personal computer. Consequently, the wire diameter of the coil spring 4 in the above-described opening/closing mechanism must be enlarged and the spring itself must be made large in size. In the prior art, therefore, a problem is that the overall opening/closing mechanism is large in size. In particular, when the opening/closing portion is opened in the example of the prior art, the coil spring 4 limits the turning of the shaft so that the position of the opening/closing portion is maintained. Thus, the coil spring 4 is used for maintaining the position of the opening/closing portion and getting pop-up action. For this reason, there is a limitation upon the placement of the spring and the wire diameter, and it is difficult to reduce the size of the mechanism. Further, it is not possible to fix the position of the opening/closing portion of the apparatus at any desired angle. Still, a holding device for a cover at an electrical apparatus has been described (CH-A-543 219). This cover is pivotally mounted on an axis parallel to the axis of a wall of the apparatus. Also, at least two pins are run on bearings of the friction type located on said cover. The disadvantage of this holding device lies in the fact that the friction type bearings consist of saucer springs the friction forces of which cannot be adjusted exactly. Technical problem The problem to be solved by the present invention is to provide an easily manufactured opening/closing mechanism of small size and with stable friction forces. Solution of the Technical Problem The above problem is solved by an opening/closing mechanism comprising a base attached to a main body of an apparatus; an arm attached to an opening/closing portion of the appratus and axially supported on the base so as to turn freely; a rotary plate which turnes together with the arm and which has a projection; a pop-up plate having an engaging portion, wherein when the opening/closing portion is closed up to a prescribed position, the engaging portion engages with the projection of the rotary plate so that at a further displacement of the opening/closing portion to its final closed position the pop-up plate turnes together with the rotary plate; and a resilient member provided between the pop-up plate and the base and compressed by turning of the pop-up plate, wherein the pop-up plate and the rotary plate are turned by this compressive force. When the opening/closing portion of the apparatus is closed up to a prescribed position, the projection formed on the rotary plate in the opening/closing mechanism of the invention engages the engaging portion of the pop-up plate. When the opening/closing portion is completely closed by being pressed, the pop-up plate turns together with the rotary plate and is stopped at a prescribed position. At this time the resilient member interposed between the pop-up plate and the base is compressed. When the opening/closing portion is released, the pop-up plate and the rotary plate are turned together by the compressive reaction force of the resilient member, thereby lifting the opening/closing portion. Advantageous effects of the invention In accordance with the invention, a coil spring is not used, and the leaf spring specifically for the pop-up plate is arranged at a location remote from the shaft. As a result, there is a large degree of freedom with regard to the shape of each part and the arrangement of the parts, and it is possible to reduce the size of the apparatus. In particular, a structure in which disks are piled is adopted as a tilt mechanism, and both the second rotary plate and pop-up plate are constituted by plate members. As a consequence, it is possible to reduce dimensions in the axial direction of the shaft. In addition, since the various parts are assembled merely by passing the shaft through them, manufacture is facilitated. Furthermore, the arrangement according to the first embodiment is such that a small force is applied to the pop-up plate by the leaf spring at all times, thereby making it possible to prevent the occurrence of gap among the parts. A further embodiment of the invention having a tilt-action only is disclosed in claim 7. Brief Description of the Drawings Fig. 1 is an exploded perspective view showing the construction of an opening/closing mechanism according to an embodiment of the present invention; Figs. 2 through 4 are diagrams showing the operation of the opening/closing mechanism illustrated in Fig. 1; Figs. 5 through 7 are diagrams showing the opening/closing operation of an apparatus, such as a personal computer, to which the opening/closing mechanism shown in Fig. 1 is attached; Fig. 8 is an exploded perspective view showing the construction of an opening/closing mechanism according to another embodiment of the present invention; Fig. 9 is a sectional view of the opening/closing mechanism shown in Fig. 8; Fig. 10 is a side view of the opening/closing mechanism shown in Fig. 8; and Fig. 11 is a perspective view showing an opening/closing mechanism according to the prior art. Detailed Description of the Drawings Referring now to Fig. 1, numeral 10 denotes a base attached to a main body 20 of an apparatus shown in Figs. 5 to 7. The base 10 has a mounting portion 10a attached to the main body 20, and a support portion 10b vertically upstanding form the mounting portion 10a and having a hole 10c at its center. Further, the support portion 10b has a stopper 10d which contacts a pop-up plate (described later) and is formed at the side face of the support portion 10b. Numeral 11 denotes a shaft comprising a small-diameter portion 11a which matches the hole 10c, a large-diameter portion 11b, and a rectangular mounting portion 11c projecting from the end face of the large-diameter portion 11b. A linear groove 11d is formed at the outer periphery of the small-diameter portion 11a of shaft 11 and in the axial direction of the shaft. Numerals 12, 13 denote first and second rotary plates each having the shape of a planar disk and holes 12a, 13a formed at the center thereof. Inwardly directed projections 12b, 13b matching the groove 11d of shaft 11 are provided at the inner peripheral portions of the holes 12a, 13a, respectively. Further, a projection 13d is provided at the outer peripheral portion of the second rotary plate 13 and bends to one side of the plate. Numeral 14 denotes a pop-up plate having a hole 14a which matches the small-diameter portion 11a, first and second engaging portions 14b, 14c provided on its outer peripheral portion with a predetermined spacing between them, and an urging portion 14d projecting in the direction of the mounting portion 10a of base 10. Numerals 15, 16 denote ring-shaped cup springs, and numeral 17 denotes a push nut attached to the tip of the small-diameter portion 11a of shaft 11. Numeral 18 denotes an arm attached to an opening/closing portion 21 such as the display portion of the apparatus shown in Figs. 5 to 7. The arm 18 has a hole 18a which matches the mounting portion 11c of shaft 11. Numeral 19 denotes a leaf spring serving as a resilient member. The leaf spring is fixed on the mounting portion 10a of base 10 and is disposed between the mounting portion 10a and the urging portion 14d of pop-up plate 14. As shown in Fig. 1, when the small-diameter portion 11a of shaft 11 has been passed through the hole 10c of base 10, the parts constituted by the first rotary plate 12, pop-up plate 14, second rotary plate 13, cup springs 15, 16 and push nut 17 are assembled on the small diameter portion 11a in the order mentioned. These parts are fixed by the push nut 17 so as to be held in pressured contact under the spring force of the cup springs 15, 16. The arm 18 is attached to the mounting portion 11c of shaft 11 before and after the aforementioned parts are assembled. The first and second rotary plates 12, 13 turn together with the shaft 11 since the projections 12b, 13b thereof are engaged with the groove 11d of shaft 11. The first and second rotary plates 12, 13, the pop-up plate 14 and the support portion 10b of base 10 are alternately disposed and held in pressured contact by the cup springs 15, 16. Consequently, a comparatively large force is required in order to turn the shaft 11 owing to the friction among these parts, and therefore it is possible to stop and fix the arm 18 at any angle. It should be noted that it is possible to change the rotary torque of the shaft 11 at will by increasing or decreasing the number of rotary plates 12, 13 and the number of disk-shaped members clamped between them. In addition, the projection 13d provided on the second rotary plate 13 is so arranged as to come into abutting contact with each of the engaging portions 14b, 14c of the pop-up plate 14 when the second rotary plate 13 is turned through a predetermined angle. Next, the operation of the opening/closing mechanism shown in Fig. 1 will be described with reference to Figs. 2 through 4 and Figs. 5 through 7. The arm 18 is attached to the shaft 11 in such a manner that the opening/closing portion 21 of the apparatus attains a widely open state, as shown in Fig. 5. In this state, the projection 13d of the second rotary plate 13 is in contact with the second engaging portion 14c of pop-up plate 14, as shown in Fig. 2. Since the arrangement is such that the outer face of the pop-up plate 14 comes into contact with the stopper 10d of base 10 under these conditions, rotation in the counter-clockwise direction in Fig. 2 is prevented. If the opening/closing portion 21 is reclined in the direction of the main body 20, the arm 18 rotates in the clockwise direction in the drawing, as illustrated in Fig. 3, and this is accompanied by rotation of the rotary plate 13 until its projection 13d abuts against the first engaging portion 14b of pop-up plate 14. With the projection 13d of the second rotary plate 13 and the first engaging portion 14b of the pop-up plate 14 brought into abutting contact, the opening/closing portion 21 assumes a slightly open state, as illustrated in Fig. 6. If the opening/closing portion 21 is now pressed to attain the state shown in Fig. 7, the second rotary plate 13 and the pop-up plate 14 engaging therewith will be rotated clock-wise in the drawing, as shown in Fig. 4, owing to the rotation of the arm 18 at this time. At this time the leaf spring 19 provided between the urging portion 14d of pop-up plate 14 and the mounting portion 10a of base 10 is compressed and adds a reaction force produced by the compression of the spring to the pop-up plate 14. If the opening/closing portion 21 is released under these conditions, the pop-up plate 14 is rotated counter-clockwise by the force of the leaf spring 19, and the second rotary plate 13, whose projection 13d is engaging with the first projection 14b of the pop-up plate, also rotates in the counter-clockwise direction. As a result, the arm 18 also rotates counter-clockwise and becomes the state shown in Fig. 3, and the opening/closing portion 21 becomes the state shown in Fig. 6. In this embodiment, the opening/closing mechanism has a pop-up mechanism for opening the opening/closing portion slightly from the completely closed state and a tilt mechanism for fixing the opening/closing portion at any angle. It is possible to divide the pop-up mechanism and tilt mechanism. For example, by omitting the cup springs 15, 16 and first rotary plate 12 from the opening/closing mechanism shown in Fig. 1, it is possible to provide the opening/closing mechanism having the pop-up action only. Then, the opening/closing mechanism having the tilt action only will be described with reference to Figs. 8 through 10. Numeral 30 denotes a base attached to the main body of an apparatus such as a personal computer. The base 30 has a mounting portion 30a attached to the main body of the apparatus, and a support portion 30b vertically upstanding from the mounting portion 30a and having a hole 30c at its center. Further, stoppers 30d, 30e are provided at the side face of the support portion 30b and contact a fixed plate (described later). Numeral 31 denotes a shaft comprising a small-diameter portion 31a which matches the hole 30c, a disk-shaped large-diameter portion 31b having a diameter larger than that of portion 31a, and a mounting portion 31c attached to an opening/closing portion of the apparatus via an arm or the like. Further, a linear groove 31d is provided at the outer periphery of the small-diameter portion 31a and in the axial direction of the shaft. Numerals 32, 33 denote first and second rotary plates each having the shape of a planar disk and having holes 32a, 33a at the center thereof. Inwardly directed projections 32b, 33b matching the groove 31d of shaft 31 are respectively provided at the inner peripheral portions of the holes 32a, 33a. Numeral 34 denotes a fixed plate in the shape of a planar disk having a hole 5a which matches the small-diameter portion 31a, and engaging portions 34b, 34c provided on the outer peripheral portion for engaging with the stoppers 30d, 30e of the base 30. Numerals 35, 36 denote ring-shaped cup springs. Numeral 37 denotes a push nut comprising a ring-shaped rim portion 37a, and a plurality of locking pieces 37b projecting toward the center of the nut from the rim portion 37a. As illustrated, the small-diameter portion 31a of the shaft 31 is passed through the hole 30c of base 30, and the above mentioned parts are mounted on the small-diameter portion 31a in the order of the first rotary plate 32, fixed plate 34, second rotary plate 33, cup springs 35, 36 and push nut 37. The first and second rotary plates 32, 33 are mounted in such a manner that their projections 32b, 33b fit into the groove 31d of shaft 31, and therefore the rotary plates turn together with the shaft 31. The fixed plate 34 is mounted in such a manner that its engaging portions 34b, 34c abut against the respective stoppers 30d, 30e of the base 30. Further, the push nut 37 is fitted onto the outer Periphery of the small-diameter portion 31a by being pushed from the end portion of the small-diameter portion 31a of shaft 31. The cup spring 36 is urged by the rim portion 37a of the push nut, and the locking portion 37b of the push nut bites into the outer periphery of the small-diameter portion 31a, whereby the push nut is fixedly attached on the small-diameter portion 31a. In the mechanism thus assembled, the fixed plate 34 is arranged between the first and second rotary plates 32, 33, and these plates are sandwiched between the support portion 30b of base 30 and the push nut 37 to be brought into contact by a constant force. As a result, a prescribed amount of friction is produced among these parts, thereby making it possible to stop rotation of the shaft 31 at any position.

Claims: An opening/closing mechanism comprising: 1.1 a base (10) attached to a main body (20) of an apparatus; 1.2 a shaft (11) rotatably supported by said base (10) and 1.3 a rotary plate (12, 13) turning together with said shaft (11), characterized by: 1.4 an arm (18) attached to an opening/closing portion (21) of said apparatus and turning together with said shaft (11); 1.5 said rotary plate (12, 13) having a projection (13d); 1.6 a pop-up plate (14) rotatably supported by said shaft (11) and having an engaging portion (14b, 14c), wherein when said opening/closing portion (21) is closed up to a prescribed position, the engaging portion (14c) engages with the projection (13d) of the rotary plate (12, 13) so that said pop-up plate (14) turns together with said rotary plate (13); and 1.7 a resilient member (19) provided between said pop-up plate (14) and said base (10) and compressed by turning of said pop-up plate (14), wherein when said opening/closing portion (21) is released, said rotary plate (13) is turned together with said pop-up plate (14) by a compressive reaction force, thereby opening/closing portion (21) up to a prescribed position. An opening/closing mechanism according to claim 1, characterized in that said shaft (11) has a linear groove (11d) which is formed at an outer periphery thereof, and wherein said rotary plate (12, 13) has an inwardly directed projection (13b) engaged with said groove of said shaft (11). An opening/closing mechanism according to claim 1, characterized in that said resilient member (19) comprises a leaf spring. An opening/closing mechanism according to claim 1, characterized in that said base (10) has a stopper (10d) which contacts said pop-up plate (14). An opening/closing mechanism according to claim 1, characterized by further comprising cup springs (15, 16) supported by said shaft (11) and a push nut (17) attached to the tip of said shaft (11) to fixe said rotary plate (12, 13), pop-up plate (14) and base (10) by the pressure of said cup spring.

Inventors: FUJITA MASAMI C O TOFUJI E M I, OKADA SHIGERU C O TOFUJI E M I, FUJITA, MASAMI, C/O TOFUJI E.M.I. CO., LTD., OKADA, SHIGERU, C/O TOFUJI E.M.I. CO., LTD.
Applicants: MATSUSHITA ELECTRIC IND CO LTD, TOFUJI E M I CO LTD, MATSUSHITA ELECTRIC INDUSTRIAL CO., LTD., TOFUJI E.M.I. CO.,LTD.
Application year: 1991
Main classification: H05K5
IPC codes: E05D11, E05F1