Patent Publication Number: US-6702506-B2

Title: Belt clip for portable electronic equipment

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a clip for attaching electronic equipment such as a portable transceiver and the like to a belt, and particularly to improvement for simplifying a detachment preventing mechanism of shaft center (guide rod) of a torsion coil spring from being detached in a case where supporting power is obtained by use of rewinding force of the torsion coil spring. 
     2. Description of the Related Art 
     In accordance with the rapid progress of semiconductor manufacturing technology, miniaturization of portable radio apparatus such as a transceiver and the like and various kinds of measuring instruments have been remarkably done in recent years. A belt clip is attached to such electronic equipment beforehand, and a user often carries the electronic equipment in a state that the electronic equipment is hung on the belt by the clip at a nonuse time. 
     In other words, the size or weight is too large in order to put it into the pocket. Or, in the case where the electronic equipment is put in a bag and the like, it is inconvenient to take out the electronic equipment from the bag every time it is need. For this reason, attachment of electronic equipment to a waist portion or a belly portion is the simplest and easiest way. 
     For example, in a conventional small-sized portable transceiver, a clip mechanism is attached to a back face of a housing as shown in FIGS. 4 and 5. 
     In FIG. 4, numeric symbol  50  denotes a transceiver main body, and a hang stopper plate  1  is fixed to a back face  50   a  through a rotational mechanism  2 . 
     As shown in FIG. 5, the rotational mechanism  2  is composed of a torsion coil spring  3 , a bracket  4 , and a pressure rod  5 . Both side plates  13   a  and  14   a  of the rectangular U-shaped bracket  4  are combined at the inner side of shaft support portions  11   a  and  12   a , which are formed to be protruded to both side portions of the hang stopper plate  1 . The torsion coil spring  3  is placed in a space formed therebetween in the combined state. The pressure rod  5  is passed through holes  11   b  and  12   b , which are formed on the shaft support portions  11   a  and  12   a , holes  13   b  and  14   b  of both side plates  13   a  and  14   a  of the bracket  4  and the interior of the torsion coil spring  3  so as to achieve an assembly. 
     Here, the hang stopper plate  1  is configured as shown in FIG.  6 . The shaft support portions  11   a  and  12   a  are formed as mentioned above, and a groove  15 , into which an arm  3   a  of the torsion coil spring  3  is fitted, is formed on the surface of the combination side with the bracket  4 . Further, holes  17   a  and  17   b  are formed at positions corresponding to holes  16   a  and  16   b  (FIG.  5 ), which are formed on an attaching plate  16  of the bracket plate  4  in a state of combination with the bracket  4 . 
     Then, the pressure rod  5  is passed therethrough and the rotational mechanism (torsion coil spring  3  and bracket  4 ) is combined with the hang stopper plate  1 . In this state, as shown in FIG. 5, screws  18   a  and  18   b  for attachment are passed through the holes  17   a  and  17   b  of the hang stopper plate  1 , so that the bracket  4  is fastened to the back face  50   a  of the transceiver main body  50 . A state after the attachment is illustrated by FIG.  7 . 
     As shown in the figure, on the back face  50   a  of the transceiver main body  50 , screw holes  51   a  and  51   b  are formed at positions corresponding to the holes  16   a  and  16   b  of the attaching plate  16  of the bracket  4 . There is also formed a concave portion  52  into which an angle portion  4   c , which is formed at an upper end of the attaching plate  16  of the bracket  4 , is fitted. The hang stopper plate  1  and the rotational mechanism  2  are tightened with screws  18   a  and  18   b  for attachment in a state that the angle portion  4   c  of the bracket  4  is fitted into the concave portion  52  of the transceiver main body  50 . 
     In this case, both side plates  13   a  and  14   a  of the bracket  4  in the rotational mechanism  2  are engaged with the hang stopper plate  1  to be opened within the fixed limit when rotating around the axis of the pressure rod  5 . For this reason, the torsion coil spring  3  is loaded in a state that the torsion coil spring  3  is twisted from a natural state (state that the arm  3   a  is rotated in a direction of arrow). 
     Therefore, in the rotational mechanism  2 , the rewinding force of the torsion coil spring  3  is used as a restoration urging force. As shown in FIG. 7, when the upper side of the hang stopper plate is pressed to the back face  50   a  of the transceiver main body  50 , the lower end of the hang stopper plate  1  is rotated in a direction of an open angle, so that a belt  60  can be received. When the pressing force is removed, the hang stopping plate  1  is returned to the original state, and the belt  60  is in a state that it is supported. 
     In addition, as shown in FIG. 6, a hook portion  19  is formed at the lower end of the hang stopping plate  1 . Unless the hang stopping plate  1  is rotated in the direction of the open angle, the hang stopping plate  1  is designed not to be detached. 
     By the way, seeing the rotational mechanism  2  shown in FIG. 7 in a plane, the result is shown in FIG. 8 (the portion of hang stopping plate  1  is shown by the cross-section). The detachment preventing mechanism of pressure rod  5  is implemented by fitting a top end portion  5   a  into the hole  12   b  formed on the shaft support portion  12   a  of the hang stopping plate  1  and by pressing a knurled portion  5   b  of the other end to the hole  11   b  formed on the shaft support portion  12   b.    
     Therefore, the relationship of a loose fining is established between the hole  12   b  of the other shaft support portion  12   a  and the shaft portion of the pressure rod  5 . However, the hole  11   b  of the shaft support portion  11   a  has an inner diameter, which is slightly smaller than the shaft diameter of the knurled portion  5   b . A crack is easily generated on the shaft support portion  11   b  when the knurled portion  5   b  is pressed, with the result that there occurs a case in which the shaft support portion  11   b  is broken at a clip using time. 
     Moreover, the pressing process is completed in such a manner that the knurled portion  5   b  is protruded a little. For this reason, there is a problem, for example, in which the protruded portion is caught on a dress at the time of detaching the transceiver main body  50  from the belt  60 . 
     In contrast, as shown in FIG. 9, there is adopted a system in which a round rod  6  having grooves  6   a  and  6   b  on an outer peripheral surface of both end portions is used in place of the pressure rod  5  and E-rings  7   a  and  7   b  are fitted into the grooves  6   a  and  6   b  after attaching the rotation mechanism  2  to the hang stopping plate  1 , thereby constituting the detachment preventing mechanism. 
     In this system, there can be considered a structure in which E-ring fitting means is used in only one end, and the other end is used as a thin head portion. 
     In these systems, it is enough that the round rod  6  is loosely fitted into the holes  11   b  and  12   b  of the respective shaft support portions  11   a  and  12   a , and there is no possibility that the crack will be generated unlike the above-mentioned case. However, the E-rings  7   a  and  7   b  are needed separately as an assembly part, and the protruded portion is also formed on the side face. For this reason, similar to the above-mentioned case, the problem occurs at the time of detaching the transceiver main body  50  from the belt  60 . 
     It is an object of the present invention to implement a detachment preventing mechanism of a shaft (corresponding to the aforementioned pressure rod  5 , round rod  6 , and corresponding to a guide rod with respect to the torsion coil spring  3 ) with an extremely simple structure, to manufacture a belt clip of portable electronic equipment with a good yield at reasonable cost in general, and to prevent occurrence of a problem, for example, in which a part of the equipment is caught on a dress at the time of detaching the portable electronic equipment. 
     SUMMARY OF THE INVENTION 
     The present invention relates a belt clip for portable electronic equipment in which a pair of shaft support portions, each having a fixed distance with respect to each opposite face of portable electronic equipment and a hang stopper plate, is structured to be protruded, and a guide rod is passed through holes formed on each of shaft support portions and an interior of a torsion coil spring mounted in a space formed between the pair of the respective shaft support portions in a state that the respective shaft support portions of portable electronic equipment and those of the hang stopper plate are combined with each, and the torsion coil spring is mounted to urge the respective opposite faces of the portable electronic equipment and the hang stopper plate where the respective arms are placed on the same side with respect to the guide rod in a state that the torsion coil spring is twisted from a natural state, the belt clip for portable electronic equipment comprises a constraint mechanism, which is formed on the faces of the portable electronic equipment side and the hang stopper plate where the respective arms of the torsion coil spring contact, for restraining movement of the guide rod of the torsion coil spring to an axial direction and a change in a coil length of the torsion coil spring generated by its mounting, wherein an outer diameter of the guide rod is set to a size such that a coil axis of the torsion coil spring mounted under the constraint conditions is inclined and at least an end portion of the torsion coil spring presses an outer peripheral surface of the guide rod, and a concave portion is formed at a position corresponding to the end portion of the torsion coil spring in the guide rod, so that the end portion is engaged with the concave portion. 
     According to the present invention, movement of the torsion coil spring to the axial direction of the guide rod is restrained by the restraint mechanism formed on the face of the portable electronic equipment and that of the hang stopping plate (constraint condition  1 ) and the change in the coil length is restrained (constraint condition  2 ), and the torsion coil spring is mounted in a state that it is twisted from the natural state under these conditions. 
     Therefore, the torsion coil spring is mounted in a state that the respective round line portions of the torsion coil spring are skewed by stress generated in a spring element wire based on constraint condition  2 , and the coil axis is inclined. 
     On the other hand, the outer diameter of the guide rod is set to a size such that at least the end portion of the torsion coil spring presses the outer peripheral surface of the guide rod. 
     Then, in this embodiment, the concave portion is formed at a position corresponding to the end portion of the torsion coil spring in the guide rod. For this reason, the end portion of the torsion coil spring is pressed to the concave portion, so that the end portion is fitted into the concave portion. However, movement of the torsion coil spring to the axial direction of the guide rod is also restrained by (constraint condition  1 ). 
     As a result, the guide rod is stopped by the torsion coil spring whose movement is restrained, and the detachment preventing mechanism of the guide rod can be formed. 
     In this invention, “the pair of shaft support portions formed on the portable electronic equipment side” does not always have to form on the electronic equipment main body directly, and the shaft support portions, which have holes on both side plates of the rectangular U-shaped bracket fixed to the face of the electronic equipment, may be used. 
     Moreover, as a “restraint mechanism”, any structure may be used if the mechanism implements the restraint conditions  1  and  2 . However, more rational and simple mechanism can be implemented by forming the constraint mechanism of a wall surface of a space for mounting the torsion coil spring at the shaft support portions on the portable electronic equipment side or the hang stopper plate side, and a fitting groove of the arm, which is formed on the surface of the portable electronic equipment side with which the arm of the torsion coil spring comes in contact or the surface of the hang stopper plate side. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The above and other objects and features of the invention will appear more fully hereinafter from a consideration of the following description taken in connection with the accompanying drawing wherein one example is illustrated by way of example, in which; 
     FIG. 1 is a plane view showing a rotational mechanism portion according to a clip of the present embodiment; 
     FIG. 2 is a view showing a relationship between an inner diameter of a torsion coil spring and an outer diameter of a guide rod in a natural state; 
     FIG. 3 is a schematic perspective view showing a state in which the torsion coil spring is mounted with torsion from the natural state and movement to an axial direction and a change in a coil length are constrained; 
     FIG. 4 is an external perspective view of a small-sized portable transceiver to which a clip mechanism relating to prior art is attached, seeing from a back face; 
     FIG. 5 is an exploded perspective view of the clip mechanism of FIG. 4; 
     FIG. 6 is a front view (A) of a hang stopping plate and a side view (B) thereof; 
     FIG. 7 is an enlarged side view showing a state in which a rotational mechanism is added to the hang stopping plate and attached to a transceiver main body; 
     FIG. 8 is a plane view of a rotational mechanism (detachment prevention is a pressing system of a knurled portion) in prior art; and 
     FIG. 9 is a plane view of a rotational mechanism (detachment prevention is an E-ring fitting system) in prior art. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     A preferred embodiment of the present invention will now be described specifically with reference to FIGS. 1 through 3. 
     First, FIG. 1 is a plane view showing a rotational mechanism portion according to a clip of a small-sized portable transceiver, and corresponds to FIGS. 8 and 9 relating to the prior art. 
     In addition, FIG. 1 also illustrates a portion of the torsion coil spring  31  by a cross-section. 
     In this embodiment, the basic structure of the hang stopping plate  1  and the bracket  4  is the same as that of the prior art. However, this embodiment has the features in the following points. 
     Namely, as a rod, which corresponds to the pressure rod  5  or round rod  6  of the prior art, there is used a guide rod  21  having a concave groove  21   a  formed on the outer peripheral surface corresponding to the position of round line  31   c , which is continued from an arm  31   a  of a torsion coil spring  31 . Moreover, the length of the guide rod  21  is set to a width of the hang stopping plate  1 . 
     Then, as shown in FIG. 2, an inner diameter D of the torsion coil spring  31  is naturally set to be larger than an outer diameter d of the guide rod  21  in a natural state. However, if the torsion coil spring  31  is mounted between the hang stopping plate  1  and the bracket  4  by the guide rod  21  as shown in FIG. 1, the arm  31   a  of the torsion coil spring  31  is twisted by an angle φ and is fitted into a groove  15  formed on the hang stopping plate  1  as shown in FIG.  3 . 
     In other words, the arm  31   a  of the torsion coil spring  31  is stopped by the groove  15  of the hang stopping plate  1   a  portion of an arm  31   b  of the other end is stopped by an attaching plate portion  16  of the bracket  4  and is in contact with a side plate  13   a . As a result, movement of the torsion coil spring  31  to an axial direction and a change in a coil length are constrained, and the torsion coil spring  31  is twisted by an angle φ from the natural state. 
     Therefore, the respective round line portions of the torsion coil spring  31  are skewed and a coil axis is inclined, and the round line portions of both ends are in a state that they press the outer peripheral surface of the guide rod  21 . However, in this embodiment, since the concave groove  21   a  is formed on the guide rod  21  as mentioned above, the round line portion  31   c  continued to the arm  31   a  is fitted into the concave groove  21   a  as shown in FIG.  1  and the torsion coil spring  31  is set between the hang stopping plate  1  and the bracket  4  in this state. 
     As a result, movement of the torsion coil spring  31  to the axial direction is constrained, and the round line portion  31   c  is engaged with the concave groove  21   a  of the guide rod  21  to constrain movement to the axial direction of the guide rod  21 . For this reason, the detachment preventing mechanism of guide rod  21  can be rationally constituted. 
     Moreover, as shown in FIG. 7, when the hang stopper plate  1  is rotated in the direction of open angle to receive the belt  60  after being opened from the back face  50   a  of the transceiver main body  50 , the torsion coil spring  31  is much largely twisted and skewed. Namely, the round line portion  31   c  of the torsion coil spring  31  is prevented from being detached from the concave groove  21   a  of the guide rod  21  by the operation of the hang stopper plate  1 . 
     Generally, in the case of using the urging force of the torsion coil spring in the rewinding direction, the outer diameter d of the guide rod is designed to have about 90% of coil inner diameter (D− Δ D) at a maximum torsion time [where  Δ D=φ max D/27πN ((p max is a maximum torsion angle and N is the number of turns of coils)] such that a large load is not applied on the guide rod by the skew of the torsion coil spring. However, this embodiment makes a reverse use of this fact, and forms the detachment preventing mechanism of guide rod  21  by using the skew of the torsion coil spring  31  effectively. 
     Therefore, in consideration of the fact that the change in the coil length of the torsion coil spring  31  is constrained, d&gt;0.9(D− Δ D) may be set as a guide for designing the rotational mechanism of the clip relating to this embodiment. 
     Then, unlike the prior art, the rotational mechanism of this embodiment eliminates the need for pressing the guide rod  21  to the shaft support portions  11   a  or  12   a  and for using the E-rings. It is enough to form the concave groove  21   a  on the guide rod  21 , and the assembly of rotational mechanism is extremely easy. 
     Furthermore, since the protruded portion is not formed on the side portion of the hang stopper plate  1 , there is not generated the problem in which the protruded portion is caught on a dress at the time of detaching the transceiver main body  50  from the belt  60 . 
     Additionally, in this embodiment, though the arm  31   a  of the torsion coil spring  31  is stopped by the groove  15  of the hang stopper plate  1 , a projection for stopping may be formed on the hang stopper plate  1 . Moreover, in this embodiment, though the bracket  4  is used to form the rotational mechanism to be independent of the transceiver main body  50 , such shaft support portions that correspond to both side plates  13   a  and  14   a  of the bracket  4 , may be directly formed on the back face  50   a  of the transceiver main body  50 . 
     The “belt clip for portable electronic equipment” of the present invention provides the following effects by having the above structure. 
     More specifically, in the portable belt clip for electronic equipment, which constituting the rotational mechanism of the hang stopper plate by use of the rewind urging force of the torsion coil spring, the detachment preventing mechanism of the guide rod, which passes through the shaft support portions and the torsion coil spring, is implemented by use of a phenomenon in which the respective round line portions are skewed when the torsion coil spring is twisted from the natural state. Unlike the prior art, neither breakage of the shaft support portions nor an increase in the number of parts occurs, and the extremely simple structure and the easiness of assembly makes it possible to achieve a reduction in cost. 
     Furthermore, it is possible to eliminate the protruded portion from the side portion of the hang stopper plate, and this brings about an advantage in which there is not generated the problem in which the protruded portion is caught on the dress at the time of detaching the portable electronic equipment. 
     While several forms of the present invention have been illustrated and described, it will be apparent that various modifications may be made without departing from the spirit and scope of the invention. Therefore the scope of the invention is not to be limited to the specific embodiments disclosed herein but is to be accorded the scope and breadth of the appended claims.