Abstract:
A magnetic hinge apparatus is applicable to a foldable product (such as folding cellular phone) for connecting the cover and the base. A practical application is provided by aligning two magnetic cams on a shaft. One magnetic cam is connected to the base, and the other is connected to the cover. Also, an attractive force is formed between the opposite surfaces of the two opposite magnetic cams. Before applying any external force on the foldable product, the convex portion of one magnetic cam completely engages the concave portion of the other magnetic cam. When the cover is opened, both magnetic cams are rotated relatively and then separated from the engaged position. When the cover keeps in opening, the convex portions of both magnetic cams are going to touch and then across each other; meanwhile, the magnetic force can attract two magnetic cams back to the engaged position. Accordingly, the foldable product secured by the magnetic hinge apparatus possesses the snap characteristic.

Description:
This application incorporates by reference of Taiwan application Serial No. 90205276, filed Apr. 4, 2001. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates in general to a hinge apparatus, and more particularly to a magnetic hinge apparatus. 
     2. Description of the Related Art 
     The trend of the portable device such as cellular phone is leaded towards the lighter, the thinner, and the smaller. Each component of the portable device has to be miniaturized. For example, cellular phone, the most popular portable product, has been through the great revolution in appearance design. Conventionally, the button portion of cellular phone is uncovered, and then a cover is added to protect the buttons from careless touch. The present cellular phone is further designed to be folded up for easy to carry. The exterior of cellular phone is lighter and handier. As a folding cellular phone presents, the display and the buttons are respectively equipped on the lid and body portion, and connected by a hinge apparatus. Hence, the folding cellular phone has an open position in the communication, and a close position at rest. The volume of cellular phone is greatly reduced due to its foldability. In the present cellular phone, a spring is mostly adopted of the hinge apparatus for providing a torsion force. 
     Referring to FIG. 1A, which shows the components of a conventional spring type hinge apparatus. The spring type hinge apparatus  100  includes a flanged shaft  102 , a first cam  104 , a second cam  106 , and a spring  108 . The first cam  104  has a convex portion  114  and a concave portion (not shown) in the profile. Also, the second cam  106  has a convex portion  116  and a concave portion  126  in the profile. 
     FIG. 1B is a perspective view of the assembled spring type hinge apparatus according to  1 A. When assembling the spring type hinge apparatus, the flanged shaft  102  is inserted through the first cam  104 , the second cam  106 , and the spring  108 . The convex portion  114  and the concave portion (not shown) of the first cam  104  are engaged with the concave portion  126  and the convex portion  116  of the second cam  106 , respectively. It is noted that the elastic force from the compressed spring  108  pushes the second cam  106  towards the first cam  104  since the spring  108  coupled to the flanged shaft  102  resists one end of the second cam  106 . Therefore, the first cam  104  and the second cam  106  are tightly engaged. 
     In the practical application, the spring type hinge apparatus  100  can be installed in any device having a cover (lid) and a base, to make the device semi-automatically open and close. For example, the spring type hinge apparatus  100 , situated in the cellular phone for connecting the cover and the base, allows the pivoting of the cover on the base. In one practical case, the first cam  104  is fixed to the base while the second cam  106  is fixed to the cover. When the cellular phone is closed, the convex portion  114  and the concave portion of the first cam  104  are engaged with the concave portion  126  and the convex portion  116  of the second cam  106 , respectively. When the cover of cellular phone is opened, the second cam  106  is simultaneously rotated with the cover so as to separate from the first cam  104 . 
     It is noted that the second cam  106  is movably engaged on the flanged shaft  102 . When the second cam  106  is rotated with the cover, the convex portion  116  is apart from the concave portion of the first cam  104 , and then moves along the profile of the first cam  104  towards the convex portion  114 ; therefore, the second cam  106  is moved outward along the flanged shaft  102 , and the spring  108  is compressed consequently. When the cover is opened to a specific angle that the convex portion  116  of the second cam  106  is against the convex portion  114  of the first cam  104 , the maximum compression of the spring  108  is achieved. If the cover keeps on opening, the convex portion  116  of the second cam  106  is going to move across the convex portion  114  of the first cam  104 , and the recovery force released from the spring  108  will push the second cam  106 ; thus, the second cam  106  moved inward along the flanged shaft  102  until the convex portion  116  of the second cam  106  engaged with another concave portion of the first cam. After both cams engage tightly again, the cellular phone is in full-opened condition. Similarly, the hinge action during the close condition is performed in reverse order. 
     Referring to FIG. 2, which shows operation of the conventional spring type hinge apparatus equipped in a folding cellular phone. The spring type hinge apparatus  100  pivotally connects the cover  200  and the base  202  of a folding cellular phone. The first cam  104  is connected to the base  202 , and the second cam  106  is connected to the cover  200 . In FIG. 2, the X-coordinate represents the rotating angle between the first cam  104  and the second cam  106 . The Y-coordinate represents the position of the second cam  106  on the flanged shaft  102 . When the opening angle of the folding cellular phone is 0°, the first cam  104  and the second cam  106  are tightly engaged to each other, and the second cam  106  is located on the flanged shaft  102  at position a. 
     When user keeps opening the cellular phone until the angle á, the convex portion  116  of the second cam  106  is apart from the concave portion of the first cam  104 , and consequently the second cam  106  moves outward (away from the first cam  104 ) along the flanged shaft  102  to position b. Meanwhile, as spring  108  is compressed, the elastic recovery force will push the second cam  106  to move the first cam  104  inward when the external force is removed. 
     When the cellular phone is opened to the angle â, the convex portion  116  of the second cam  106  touches the convex portion  114  of the first cam  104 . Meanwhile, the second cam  106  slides along the flanged shaft  102  to position c, and the compression of the spring  108  has reached its maximum. Consequently, an elastic recovery force is generated in converse direction. According to the foregoing illustration, it is required an external force to overcome the elastic recovery force while the opening angle has switched from 0° to â. 
     When the opening force to the cover  200  is continued and the opening angle is ã, the convex portion  116  of the second cam  106  is separated from the convex portion  114  of the first cam  104 , and moves towards the other concave portion of the first cam  104 . Simultaneously, the second cam  106  is propelled by the elastic recovery force generated from the compressed spring  108 , and moves close to the first cam  104 . Therefore, the cover is automatically flipped up without applying any external force. 
     When the cellular phone is full-opened (the opening angle is 180°), the convex portion  116  of the second cam  106  engages with the concave portion of the first cam  104 , and the second cam  106  on the flanged shaft  102  is back to position a. In the meanwhile, the elastic recovery force of the spring  108  is completely released and recovers to the original uncompressed state. 
     The foregoing paragraphs clearly describe the operation of spring type hinge apparatus  100 . Also, it is known that the open-close situation of cellular phone (180°˜0°) with the reference of FIG.  2 . 
     Generally, when the cellular phone is opened from the closed position to the angle â, an external force is required to open the cover  200 . In the meanwhile, the second cam  106  and the first cam  104  have approached the unstable state and attain the critical situation (which the convex portions are against to each other). Also, the spring  108  is compressed to the shortest condition. When the cellular phone keeps opening from the angle â to the full-opened position, the compressed spring  108  releases the elastic recovery force and pushes the second cam  106  to engage the first cam  104 . Accordingly, the cellular phone equipped with the spring type hinge apparatus  100  possesses snap characteristic, wherein the cover in a certain angle is snapped into the full-opened position (ranged from â to 180°) or snapped into the closed position (ranged from â to 0°), without applying any external force. 
     However, the conventional spring type hinge apparatus  100  will loss the property of returning to the initial state following deformation after frequent usage. Also, it requires more space to install the spring type hinge apparatus  100  since the spring  108  occupies certain room. This increases the overall size of applied product. 
     SUMMARY OF THE INVENTION 
     It is therefore an object of the invention to provide a magnetic hinge apparatus to substitute the elastic force of conventional spring by the principle of magnetism. Because the like poles repel each other and the unlike poles attract each other, the product secured by the magnetic hinge apparatus of the invention possesses the snapping characteristic. 
     The invention achieves the above-identified objects by providing a magnetic hinge apparatus for connecting the cover and the base of the foldable product. The magnetic hinge apparatus comprises a shaft, the first, second, and third magnetic cams. In the practical application, the first magnetic cam connected to the base can be arranged on one end of the shaft, while the other end of the shaft is installed with the third magnetic cam. The second magnetic cam connected to the cover can be aligned between the first and the third magnetic cams. Both the second and third cams are connected to the cover. What the point of the invention is either the attractive force existing in the opposite profiles of the first magnetic cam and the second magnetic cam, or the repulsion force existing in the opposite profiles of the second magnetic cam and the third magnetic cam, or a combination thereof. The principle of magnetism makes the first magnetic cam and the second magnetic cam engage spontaneously. 
     Moreover, both opposite profiles of the first magnetic cam and the second magnetic cam have a convex portion and a convex portion. When the foldable product is full-closed, the convex portion of the second magnetic cam engages the concave portion of the first magnetic cam. When the cover of applied product is opened by an external force, the convex portion of the second magnetic cam is separated from the concave portion of the first magnetic cam, and slides on the profile of the first magnetic cam; meanwhile, the second magnetic cam moves toward the third magnetic cam. When the cover keeps opening and both concave portions of the first magnetic cam and the second magnetic cam touch each other, both cams are in the unsteady state. If the cover keeps opening, both concave portions of the first magnetic cam and the second magnetic cam will be separated; meanwhile, the attractive force (between the first magnetic cam and the second magnetic cam) and repulsion force (between the second magnetic cam and the third magnetic cam) are going to push the second magnetic cam. Under this condition, even the applying external force disappears, the second magnetic cam will spontaneously move towards the first magnetic until complete engagement is achieved. As a result, the cover is automatically opened to the full-opened state. Similarly, the magnetic hinge apparatus works in reverse order while the cover is rotated from the full-opened position to full-closed position. Accordingly, the foldable product secured by the magnetic hinge apparatus possesses snap characteristic. 
     Other objects, features, and advantages of the invention will become apparent from the following detailed description of the preferred but non-limiting embodiments. The following description is made with reference to the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1A (Prior Art) shows the components of a conventional spring type hinge apparatus; 
     FIG. 1B (Prior Art) is a perspective view of the assembled spring type hinge apparatus according to  1 A; 
     FIG. 2 (Prior Art) shows operation of the conventional spring type hinge apparatus equipped in a folding cellular phone; 
     FIG. 3A is a side view of the magnetic hinge apparatus according to an embodiment of the invention; 
     FIG. 3B is a three-dimensional drawing of magnetic hinge apparatus of FIG. 3A; 
     FIG. 3C is the assembled magnetic hinge apparatus according to an embodiment of the invention; 
     FIG. 3D is a side view of magnetic hinge apparatus of FIG. 3C; 
     FIG. 4A is an explored drawing of the folding cellular phone secured by the magnetic hinge apparatus according to the embodiment of the invention; 
     FIG. 4B shows the folding actions of the cellular phone assembled with the magnetic hinge apparatus of FIG. 4A; 
     FIG. 5A is an enlarged, perspective view of the magnetic hinge apparatus resided in the full-closed cellular phone of FIG. 4B; and 
     FIG. 5B is an enlarged, perspective view of the magnetic hinge apparatus resided in the opened cellular phone of FIG.  4 B. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to FIG. 3A, which is a side view of the magnetic hinge apparatus according to an embodiment of the invention. The magnetic hinge apparatus  300  includes a flanged shaft  302 , a first magnetic cam  304 , a second magnetic cam  306 , and a third magnetic cam  308 . The first magnetic cam  304  has the profiles  334  and  344 , the second magnetic cam  306  has the profiles  336  and  346 , and the third magnetic cam  308  has a profile  338 . 
     Also, the profile  344  of the first magnetic cam  304  and the profile  336  of the second magnetic cam  306  possess the opposite polarities. On the contrary, the profile  346  of the second magnetic cam  306  and the profile  338  of the third magnetic cam  308  possess the like polarities. For example, if the profile  344  is determined to be a north (N) magnetic pole, the profiles  336 ,  346 , and  338  are respectively a south (S), a north (N), and a north (N) magnetic pole. Accordingly, the profile  344  attracts the profiles  336  while the profile  346  repels the profile  338 . 
     FIG. 3B is a three-dimensional drawing of magnetic hinge apparatus of FIG.  3 A. The profile  344  of the first magnetic cam  304  further comprises a couple of convex portion  314  and concave portion (concave portion not shown in FIG. 3B due to the view angle limitation). The profile  336  of the second magnetic cam  306  further comprises a convex portion  316  and concave portion  326 , wherein the concave portion  326  engages the convex portion  314  and the convex portion  316  engages the concave portion of the first magnetic cam  304 . 
     FIG. 3C is the assembled magnetic hinge apparatus according to an embodiment of the invention. The first magnetic cam  304 , the second magnetic cam  306 , and the third magnetic cam  308  are mounted on the flanged shaft  302  one by one. Then, one end of the flanged shaft  302  is embossed in order to hold the third magnetic cam  308  from dropping out. The first magnetic cam  304  and the third magnetic cam  308  are positioned at two ends of the flanged shaft  302 . Because the profiles  344  and  336  possess opposite polarities, the first magnetic cam  304  and the second magnetic cam  306  are attracted to each other and engaged together. The profiles  338  and  346  possess like polarities, so that the second magnetic cam  306  and the third magnetic cam  308  repel to each other in a certain distance. 
     FIG. 3D is a side view of magnetic hinge apparatus of FIG.  3 C. The broken lines represent the lines of magnetic force, wherein the repellent lines of magnetic force indicates that the profile  346  of the second magnetic cam  306  has the same polarity as the profile  338  of the third magnetic cam  308  (i.e. both are N magnetic poles or S magnetic poles). Because the profile  336  of the second magnetic cam  306  has completely engaged the profile  344  of the first magnetic cam  304 , the attractive lines of magnetic force between both profiles are not shown in FIG.  3 D. 
     The magnetic hinge apparatus  300  of the invention is applicable to different kinds of folding product. In this preferred embodiment, a folding cellular phone is taken to illustrate how the magnetic hinge apparatus  300  works. 
     FIG. 4A is an explored drawing of the folding cellular phone secured by the magnetic hinge apparatus according to the embodiment of the invention. The cellular phone comprises a cover  400  and a base  402 . A sleeve  404  resided behind the cover  400  is used for fitting the hinge. Hence, an aperture  414  is further formed in each end of the sleeve  404 , and has identical sectional area as the magnetic hinge apparatus  300  does. Also, there are a groove  424  formed in the aperture  414  and two knuckles  406  resided in two rear ends of the base  402 . A socket  416 , a female-type connector formed in a surface of knuckle  406 , is shaped to accept and secure a suitably shaped prong of magnetic hinge apparatus  300 . During assembly of the cover  400  and the base  402 , the magnetic hinge apparatus  300  is inserted into the aperture  414  of the sleeve  404 , and then engaged with the socket  416  of the knuckle  406 . 
     FIG. 4B shows the folding operations of the cellular phone assembled with the magnetic hinge apparatus of FIG.  4 A. After completely assembly, the magnetic hinge apparatus  300  allows the pivoting of the cover  400  on the base  402 , along  4 A— 4 A axis of rotation (shown in FIG.  4 A). In FIG. 4B, (i) and (iv) depict a full-closed and a full-opened positions of the cellular phone, respectively. e,acu  represents the maximum opening angle between the cover  400  and the base  402 . 
     FIG. 5A is an enlarged, perspective view of the magnetic hinge apparatus resided in the full-closed cellular phone of FIG.  4 B. In FIG. 5A, the socket  416  of the knuckle  406  accepts and secures the first magnetic cam  304 ; therefore, it doesn&#39;t allow the turning of the first magnetic cam  304  in the socket  416 . The bottom of the second magnetic cam  306  is jointed to the groove  424  of the sleeve  404 . By particular design in the shapes of the groove  424  and bottom of the second magnetic cam  306 , the second magnetic cam  306  is able to move transversely along the flanged shaft  302  only. Also, the bottom of the third magnetic cam  308  is jointed to the groove  424 . Because the opposite profiles of the first magnetic cam  304  and the second magnetic cam  306  possess the opposite polarities, they attract to each other naturally, wherein the concave portion  326  and the convex portion  316  of the second magnetic cam  306  engage the convex portion  314  and the concave portion of the first magnetic cam  304 . On the other hand, the opposite profiles of the second magnetic cam  306  and the third magnetic cam  308  possess the same polarity, so that magnetic repulsion keeps the third magnetic cam  308  and the movable second magnetic cam  306  in the shaft as far as they can. 
     FIG. 5B is an enlarged, perspective view of the magnetic hinge apparatus resided in the opened cellular phone of FIG.  4 B. When the cover  400  of the cellular phone is opened, the first magnetic cam  304  is not able to rotate in the socket  416  but the second magnetic cam  306  jointed to the groove  424  of the sleeve  404  rotates along with the cover  400 , as shown in FIG.  5 B. The convex portion  316  of the second magnetic cam  306  separates from the concave portion of the first magnetic cam  304 , and both cams cannot completely engage to each other. Consequently, the second magnetic cam  306  moves toward the third magnetic cam  308  along the flanged shaft  302 . In the meanwhile, an external force is required to overcome not only the attractive force between the first magnetic cam  304  and the second magnetic cam  306 , but also the magnetic repulsion between the second magnetic cam  306  and the third magnetic cam  308 . 
     Moreover, the curve in FIG. 2 can represent the operation of magnetic hinge apparatus while applied in the folding cellular phone. Simply saying, a magnetic cam substitutes the spring  108  of FIG.  2  and magnetic material are adopted in the invention. It is a great improvement that elastic recovery force of the conventional spring is replaced with magnetic repulsion of the cams having the same polarity. Also, the magnetic force between the opposite polarities makes the cams to be jointed easy to engage again. 
     In the present invention, the first cam  104 , the second cam  106  and the spring  108  of FIG. 2 are replaced by the first magnetic cam  304 , the second magnetic cam  306  and the third magnetic cam  308 , respectively. The diagram, that exhibits the relationship between the rotating angle é (between the first magnetic cam  304  and the second magnetic cam  306 ) and position of the second magnetic cam  306  on the flanged shaft  302 , is the same as FIG.  2 . Therefore, the folding cellular phone secured by the magnetic hinge apparatus  300 , like secured by the spring type hinge apparatus  100 , possesses the characteristic that: when the cover is opened to a certain angle and the external force is gone, the cover can automatically snap into the full-opened position or snap into the closed position. 
     Compared to the conventional spring type hinge apparatus  100 , the point of the magnetic hinge apparatus  300  is that the third magnetic cam  308  substitutes the spring  108 , and the first magnetic cam  304 , the second magnetic cam  306  substitute the first cam  104  and the second cam  106  made by traditional material. Furthermore, there are an attractive force between the first magnetic cam  304  and the second magnetic cam  306 , and a repulsion force between the second magnetic cam  306  and the third magnetic cam  308 . Correspondingly, the second magnetic cam  306  is able to move more steadily and rapidly towards the first magnetic cam  304 . 
     According to the aforementioned embodiment, three cams of the hinge apparatus are made by magnetic material. However, the invention is not limited hereto. The operation of magnetic hinge apparatus still works well under certain conditions. It is not a required restriction that all cams are magnetic. For example, if the first and the second cams are the only components made by magnetic material, the attractive force existing between the profiles  344  and  336  (which have the opposite polarities) is able to bring two cams back to the engaged position while the external forced disappears. In another case, if the second and the third cams are the only components made by magnetic material, the operation of the magnetic hinge apparatus  300  is achieved by the repulsion force between two cams. Therefore, the applied product such as folding cellular phone still possesses flip characteristic, and the problem of elastic deformation caused by the conventional spring is also solved. 
     Additionally, the third magnetic cam  308  could be omitted in the present invention. The operation of the hinge apparatus is achieved by using the mutual attractive force between the first magnetic cam  304  and the second magnetic cam  306 . 
     However, the one of ordinary skill in the art should know that the invention is not limited to the disclosed embodiment. The way of connecting each component of the magnetic hinge apparatus to the cover or the base can be modified on the premise that the first magnetic cam  304  and the second magnetic cam  306  are able to separate and engage smoothly. So, the cover and the base of applied product can snap into the full-opened or closed position, without continuously applying the external force. 
     In the preferred embodiments described herein, the advantages of the magnetic hinge apparatus  300  of the invention are summarized as follows: 
     1. all components of the magnetic hinge apparatus  300  are made by the magnetic material. Because the unlike poles (of the first magnetic cam  304  and the second magnetic cam  306 ) attract each other, and/or like poles (of the second cam  306  and the third cam  308 ) repel each other, the second magnetic cam  306  can move steadily and rapidly toward the first magnetic cam  304 . Thus, the product secured by the magnetic hinge apparatus  300  possesses snapping characteristic. 
     2. A conventional spring type hinge apparatus could face the problem of elasticity decay after frequent usage. This problem is solved by using magnetic cams of the invention. The repulsion force of two magnetic cams substitutes the elastic recovery force of spring, so that the utility life span of hinge apparatus is greatly prolonged. 
     3. in the practical application, a useful magnetic cam is smaller than a spring; hence, the overall size of applied product can be reduced. 
     While the invention has been described by way of example and in terms of a preferred embodiment, it is to be understood that the invention is not limited thereto. On the contrary, it is intended to cover various modifications and similar arrangements and procedures, and the scope of the appended claims therefore should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements and procedures.