Hinge mechanism for foldable electronic apparatus

Abstract: A hinge mechanism for a foldable electronic apparatus having a first and a second casing. A first and a second cylindrical hinge are provided on the first and second casings, respectively. The second hinge is formed with lugs each having two contact faces having angles α and β (smaller than α). A locking member is received in the first hinge and provided with recesses each contacting one of the lugs at either of the angles α and β, depending on the direction of rotation, i.e., the folding direction or the unfolding direction.

Description: The present invention relates to the structure of a foldable electronic apparatus and, more particularly, to a hinge mechanism for a hand-held radio communication apparatus. A hand-held radio communication apparatus, e.g., a hand-held mobile telephone is one of portable electronic apparatuses extensively used today. For miniaturization, it is a common practice with such a hand-held radio communication apparatus to divide the casing thereof into two and connect the two casing parts by a hinge mechanism. In this configuration, the casing parts are rotatable about the hinge mechanism toward and away from each other, i.e., the apparatus is foldable. The casing parts are locked in a position where they are spaced apart by a predetermined angle by lugs and recesses included in the hinge mechanism. To unlock the casing parts, a force greater than the bias of a spring also included in the hinge mechanism is exerted on the casing parts. The prerequisite with such a mechanism is that the bias of the spring be greater than the predetermined force associated with the predetermined angle, so that the mechanism may rotate beyond the predetermined angle only when a force greater than the predetermined force acts thereon. This brings about a problem that the apparatus cannot be folded or unfolded from or to the predetermined angle unless a force overcoming the bias of the spring is exerted. Should use be made of a spring exerting a relatively small bias to eliminate the above problem, the casing parts locked at the predetermined angle would be easily unlocked by a small effort. In the specification of European patent application number 89311370.4 which was published under number 367610 on May 9 1990, there was described a hinge mechanism for a foldable telephone apparatus having a flip element which was held in the closed and open positions by a single enclosed cam which followed recesses in a single shaft which secured two hinge elements. The hook-switch of the telephone was activated by another enclosed cam, which followed a recess in a second shaft. In the specification of United States patent number 4,822,965, which was published on April 18 1989, there was disclosed a locking mechanism for the lid of an automobile switch panel arranged in a case. Pivotal shafts were provided in the case, and clutch members were provided in a pair of holes in the lid. The lid, which was maintained in a locked condition at a predetermined opening angle, could be closed upon the exertion of a force stronger than a predetermined level. Features of a hinge mechanism for a foldable electronic apparatus to be described below, by way of example in illustration of the invention, are that it is easy to operate, and protects the apparatus from damage. A hinge mechanism for rotatably connecting a first and a second casing of a foldable electronic apparatus to be described below by way of example in illustration of the present invention includes a first hinge provided on the first casing and having a first engaging portion, and a second hinge provided on the second casing and having a second engaging portion mating with the first engaging portion of the first hinge such that the first and second casings are locked in positions spaced apart by a predetermined angle from each other. The second engaging portion mates with the first engaging portion in a condition which differs from one direction of rotation to the other direction of rotation of the first and second casings. The following description and drawings disclose a previously proposed arrangement, together with, by means of an example, the invention which is characterised in the appended claims, whose terms determine the extent of the protection conferred hereby. In the claims:- Claim 1 seeks protection for a hinge mechanism for rotatably connecting a first and a second casing of a foldable electronic apparatus, including first hinge means provided on the first casing and having first engaging means, and second hinge means provided on the second casing and having second engaging means for mating with the first engaging means of the first hinge means such that the first and second casings may be locked in positions spaced apart by a predetermined angle from each other, characterised in that the condition of mating of the second engaging means mating with the first engaging means differs from one direction of rotation to the other direction of rotation of the first and second casings, that the first hinge means have a cylindrical hinge member and a locking member received in the cylindrical hinge member, that the second hinge means is a cylindrical hinge member, that the locking member is movable in the direction of the length of and within the first hinge means and is coupled to the first hinge means for rotation therewith, that the locking member is urged towards the second hinge means by a spring, that the first engaging means includes recesses formed in one end of the locking member which faces the cylindrical hinge member of the second hinge means, the second engaging means includes lugs formed on one end of the cylindrical hinge member which faces the one end of the locking member, each mating with one of the recesses of the locking member, and in that the lugs of the second engaging means each contacts one of the recesses of the first engaging means at a contact angle which differs from one direction of rotation to the other direction of rotation of the first and second casings. In the drawings:- FIG. 1 is a perspective view of a foldable electronic apparatus to which the present invention is applicable; FIG. 2 is a sectional side elevation showing a previously proposed hinge mechanism; FIG. 3 is an exploded perspective view of a hinge mechanism embodying the present invention; FIG. 4A is a front view showing a second hinge included in the embodiment in detail; FIGS. 4B and 4C are side elevations showing the second hinge as viewed from opposite sides; FIG. 5A is a front view of a locking member included in the embodiment; FIGS. 5B and 5C are side elevations of the locking member as viewed from opposite sides; FIG. 6 is a sectional side elevation showing a first hinge and the second hinge in a locking position; FIG. 7 is a fragmentary enlarged view showing the locking position of the hinge mechanism in more detail. DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1 of the drawings, a foldable electronic apparatus to which the present invention is applicable is shown and implemented as a hand-held mobile telephone by way of example. As shown, the telephone has a first casing 10 and a second casing 12 which are rotatably connected together by a pair of hinge mechanisms 14 having an identical configuration. The hinge mechanisms 14 each has a cylindrical first hinge 14a connected to the casing 10, and a cylindrical second hinge 14b connected to the casing 12. The hinges 14a and 14b are configured such that the casings 10 and 12 are locked in a position where they are spaced apart by a predetermined angle . FIG. 2 shows a conventional arrangement of the first and second hinges 14a and 14b. The hinge 14a is provided with semispherical recesses 16 on the end thereof which faces the hinge 14b. On the other hand, the hinge 14b is provided with semispherical lugs 18 on the end thereof which faces the hinge 14a, the lugs 18 mating with the recesses 16. More specifically, a cylindrical locking member 20 is received in the cylindrical hinge 14b and formed with the recesses 16 on the end thereof which faces the hinge 14b. A coil spring 22 is accommodated in the locking member 20 to constantly urge the member 20 against the hinge 14b via a screw 24. The problem with this kind of arrangement is that the bias of the spring 22 is difficult to set, as stated earlier. A preferred embodiment of the hinge mechanism in accordance with the present invention which eliminates the above problem will be described hereinafter. In the embodiment, the same or similar constituents to the constituents of the mechanism shown in FIGS. 1 and 2 are designated by like reference numerals. Referring to FIG. 3, the hinge mechanism embodying the present invention has a cylindrical first hinge 14a and a cylindrical second hinge 14b. A pair of guide ribs 26 (only one is visible) are provided on the inner periphery of the first hinge 14a and extend in the axial direction of the hinge 14a. Trapezoidal lugs 28 are provided on the end of the second hinge 14b that faces the first hinge 14a. A cylindrical locking member 20 has guide grooves 30 each mating with one of the guide ribs 26 on the outer periphery thereof. Also, the locking member 20 has recesses 32 on the end thereof which faces the hinge 14b when the member 20 is inserted into the hinge 14a via a screw 24 and a spring 22. The recesses 32 each mates with one of the lugs 28 of the hinge 14b. FIG. 4A is a front view showing the configuration of the lugs 28 of the hinge 14b in detail. The lugs 28 appear as shown in FIGS. 4B and 4C when seen from opposite sides. FIG. 5A shows the configurations of the recesses 32 and guide grooves 30 of the locking member 20 in detail. FIGS. 5B and 5C are side elevations of the recesses 32 and guide grooves 30 as viewed from opposite sides. As shown in FIG. 6, when the recesses 32 of the first hinge 14a and the lugs 28 of the second hinge 14b mate with each other, the hinges 14a and 14b are locked in position. Specifically, the hinges 14a and 14b are locked to each other when the apparatus is unfolded to the angle , as shown in FIG. 1. As shown in FIG. 7, in the locked state, each of the recesses 32 of the locking member 20 and the associated lug 28 of the second hinge 14b make contact angles α and β which are different from each other. For example, assume that when the two casings 10 and 12 are rotated toward each other, i.e., in the folding direction, the contact angle α holds. Then, if the contact angle α is selected to be greater than or equal to 45 degrees, the casings 10 and 12 can be rotated by a relatively small effort. Assume that the contact angle β holds when the casings 10 and 12 are urged further from the ordinary position for use in the unfolding direction. Then, if the contact angle β is selected to be smaller than 45 degrees (β being smaller than α), the casings 10 and 12 will be prevented from being unfolded more than the angle . In summary, it will be seen that the present invention provides a hinge mechanism which allows each of the force for folding an electronic apparatus and the force for unfolding it to have a different value. Hence, the apparatus is easy to fold and is not unfoldable beyond the ordinary position for use unless an excessive force is inadvertently exerted thereon. This is successful in promoting easy operation of the apparatus and protecting the apparatus against damage. It will be understood that, although the invention has been illustrated, by way of example, with reference to a particular embodiment, variations and modifications thereof, as well as other embodiments may be made within the scope of the appended claims.

Claims: A hinge mechanism for rotatably connecting a first and a second casing (10, 12) of a foldable electronic apparatus, including first hinge means (14a) provided on the first casing (10) and having first engaging means (32), and second hinge means (14b) provided on the second casing (12) and having second engaging means (28) for mating with the first engaging means (32) of the first hinge means (14a) such that the first and second casings (10, 12) may be locked in positions spaced apart by a predetermined angle from each other, characterised in that the condition of mating of the second engaging means (28) mating with the first engaging means (32) differs from one direction of rotation to the other direction of rotation of the first and second casings (10 12), that the first hinge means (14a) have a cylindrical hinge member and a locking member (20) received in the cylindrical hinge member, that the second hinge means (14b) is a cylindrical hinge member, that the locking member (20) is movable in the direction of the length of and within the first hinge means (14a) and is coupled to the first hinge means (14a) for rotation therewith, that the locking member (20) is urged towards the second hinge means (14b) by a spring (22), that the first engaging means (32) includes recesses (32) formed in one end of the locking member (20) which faces the cylindrical hinge member of the second hinge means (14b), the second engaging means (28) includes lugs (28) formed on one end of the cylindrical hinge member which faces the one end of the locking member (20), each mating with one of the recesses (32) of the locking member (20), and in that the lugs (28) of the second engaging means (28) each contacts one of the recesses (32) of the first engaging means at a contact angle which differs from one direction of rotation to the other direction of rotation of the first and second casings. A hinge mechanism as claimed in claim 1, wherein assuming that the contact angle is α when the first and second casings (10, 12) are rotated in a folding direction, α is selected to be greater than or equal to 45 degrees while, assuming that the contact angle is β when said first and second casings (10, 12) are rotated in an unfolding direction, β is selected to be smaller than 45 degrees.

Inventors: KOBAYASHI FUMIYUKI, KOBAYASHI, FUMIYUKI, KOBAYASHI, FUMIYUKI, C/O NEC CORPORATION
Applicants: NIPPON ELECTRIC CO, NEC CORPORATION
Application year: 1992
Main classification: H04M1
IPC codes: E05D11, H04M1