Abstract:
A tilt hinge for office equipment such as a compact personal computer, has a mounting plate and a bearing plate that is at right angles to the mounting plate. A torque generating part of a shaft is press fit into one part of an elastic fastening curl member. The curl part is at the tip of the bearing plate. Another torque part of the shaft is also press fit into a modified curl part of the curl member. The curl part is moved circumferentially by an adjustment screw so that torque generated by the torque generating part of the shaft can be adjusted and is stable. The modified engaging curl part also has a flat part pressed against a portion of the shaft on an inner surface of the curl member.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention concerns a curl type tilt hinge for office automation equipment, which is mounted between a keyboard unit and a display unit of an office automation equipment, in particular, a compact personal computer, etc. and is favorable for opening and closing the keyboard unit, which is a first member, and the display unit, which is a second member, in a relative manner and stopping and maintaining these members at an arbitrary opening angle. 
     2. Description of the Prior Art 
     As a prior art, a tilt hinge for office automation equipment is known with which a fastening curl part, having a fastening curl member, is formed on a bearing plate part of a mounted member to be mounted to the main device unit, which is a first member, such as a keyboard unit, and upon inserting a rotating shaft, which supports a display unit, which is a second member and serves as an opening and closing member, into the fastening curl part, the fastening curl member is moved towards the bearing plate side by means of a fastening screw to fasten the outer circumference of the rotating shaft and generate frictional torque. 
     Japanese Un-examined Patent Publication No. Hei-10-47337 also discloses such a curl type tilt hinge, which is comprised of a mounting member, having a curl part provided with elasticity, a shaft that is press fitted into the abovementioned curl part of the mounting member, and a bracket that is mounted to this shaft, and with which the cross-sectional shape of inner side of the curl part is made a circular shape that is matched as much as possible to the outer shape of the shaft. 
     With the former of the above-described prior-art tilt hinges, though the frictional torque that the fastening curl part creates by fastening the outer circumference of the rotating shaft can be adjusted in each product by means of the fastening screw, the frictional torque, though changing slightly with time, is substantially fixed and the frictional torque cannot be made to vary in the process of opening and closing the display unit. 
     The latter of the above-described prior art (Japanese Un-examined Patent Publication No. Hei-10-47337), is called a stage-less tilt hinge since the keyboard unit and the display unit, which are the first member and second member, respectively, that are opened and closed in a relative manner, can be stopped and maintained at an arbitrary opening position in a stage-less manner. However, as shown in FIGS. 12 and 13, since the shape of the hole part  20   a  of curl part  20  will not be completely the same in each part but will vary no matter how high the precision is made, the points (indicated by filled circles) at which the outer circumference of a shaft  21 , which is press fitted into curl part  20 , contacts the inner side of the hole part  20   a  of curl part  20  will differ with each part and since the spring characteristics of the curl part will thus vary, the rotational torque created by each tilt hinge will not be the same. 
     Also, since the gap between the inner side of curl part  20  and the outer circumference of shaft  21 , which is press fitted into this curl part  20 , will obviously be extremely minute, lubrication effects will not be exhibited effectively. Though a collar, having a plurality of small holes, grooves, or indented parts, is thus press fitted between shaft  21  and the inner side of curl part  20 , the number of parts is made large and this has been an obstacle in lowering the manufacturing cost. 
     3. Object(s) of the Invention 
     An object of this invention is to provide a tilt hinge for office automation equipment, with which, by means of a simple arrangement, the frictional torque can be made to vary in the process of the opening and closing operation of a keyboard unit, which is a first member that serves as the main device unit, and a display unit, which is a second member. 
     Another object of this invention is to provide a tilt hinge, with which the dispersion of the rotational torque that is generated is made as small as possible and yet with which component parts are eliminated to make the manufacturing cost low. 
     In order to achieve the above objects, this invention provides a tilt hinge for office automation equipment, comprised of a mounting member, having a mounting plate part and a bearing plate part that is bent at a right angle with respect to the mounting plate part, an engaging curl part, which is provided with elasticity and is disposed at the tip of the abovementioned bearing plate part of the mounting member, and a shaft, having a torque generating part that is press fitted into the engaging curl part, a tilt hinge for office automation equipment characterized in that the abovementioned engaging curl part is comprised of a fastening curl part, having a fastening curl member, and a modified engaging curl part, having the axial center in common with the fastening curl part, the torque generating part of the abovementioned shaft is comprised of a main torque generating part, which is press fitted into the abovementioned fastening curl part, and a sub torque generating part, which is press fitted into the abovementioned modified engaging curl part, and the relative rotational torque between the abovementioned shaft and engaging curl part is adjusted by moving the fastening curl member of the abovementioned fastening curl part in the circumferential direction by means of an adjustment screw and thereby adjusting the fastening force applied to the main torque generating part. 
     With this arrangement by this invention, oil grooves or oil holes for lubricating oil may be provided on the outer circumference of the main torque generating part of the abovementioned shaft that is fastened by the abovementioned fastening curl part. 
     Furthermore with this invention, the bearing hole of the abovementioned engaging curl part may be made to have a D-like cross-sectional shape and the outer shape of the sub torque generating part of the rotating shaft that is press fitted into the bearing hole may likewise be made to have a D-like cross-sectional shape. 
     Also with this invention, an expanding slot may be provided between the fastening curl part and modified engaging curl part of the abovementioned mounting member and a flange part, provided on the abovementioned shaft, may be engaged with this expanding slot. 
     Also with this invention, a flat part, which is press contacted against a portion of the abovementioned shaft in the axial direction, may be provided on at least a part of the inner side of the abovementioned engaging curl part. 
     With the above arrangement by this invention, the abovementioned engaging curl part may be comprised of independent members and be fixed to a separately provided mounting member. 
     Furthermore with this invention, the abovementioned engaging curl part may be comprised of at least two engaging curl parts that are made opposite in the direction of engagement. 
     Furthermore with this invention, the abovementioned shaft may be a rotating shaft. 
     Furthermore with this invention, the abovementioned shaft may be fixed and the abovementioned mounting member may be arranged to rotate about the axis of this shaft. 
     Furthermore with this invention, one or more oil grooves or indented parts for keeping lubricating oil may be provided on the outer circumference of the abovementioned shaft. 
     Also with this invention, the engaging curl part may be comprised of both a fastening curl part, which has a fastening curl member, and a modified engaging curl part. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a front view of a tilt hinge for office automation equipment by this invention. 
     FIG. 2 is a right side view of the tilt hinge for office automation equipment by this invention. 
     FIG. 3 is an exploded perspective view of the tilt hinge for office automation equipment by this invention. 
     FIG. 4 is a sectional view along line A—A of FIG.  1 . 
     FIG. 5 is an explanatory diagram for explaining the operation of the tilt hinge for office automation equipment by this invention. 
     FIG. 6 is an explanatory diagram for explaining the operation of the tilt hinge for office automation equipment by this invention. 
     FIG. 7 is a front view, which shows another embodiment of a tilt hinge for office automation equipment by this invention. 
     FIG. 8 is an exploded perspective view of the tilt hinge for office automation equipment shown in FIG.  7 . 
     FIG. 9 is a sectional view along line A—A of FIG.  7 . 
     FIG. 10 is a right side view of the tilt hinge for office automation equipment shown in FIG.  7 . 
     FIG. 11 is an explanatory diagram for explaining the principal parts of the tilt hinge for office automation equipment shown in FIGS. 7 to  10 . 
     FIG. 12 is an explanatory diagram, which illustrates the problems of a prior art in somewhat exaggerated manner. 
     FIG. 13 is an explanatory diagram, which illustrates the problems of the prior art in somewhat exaggerated manner. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The drawings show an embodiment of this invention, and in FIGS. 1 through 6, reference numeral  1  indicates a mounting member, comprised of a mounting plate part  1   a , which is mounted to a keyboard unit A (first member), which functions as the main device unit of an office automation equipment, such as a compact personal computer, etc., and a bearing plate lb, which is formed so as to bend upwards at a right angle with respect to the mounting plate part  1   a . An engaging curl part  10  is provided at one side of bearing plate part  1   b  of mounting member  1 . This engaging curl part  10  is partitioned by an expanding slot  2  and thereby provided with a fastening curl part  3 , having a fastening curl member  3   a , and a modified fastening part  4 , with the axial center thereof being in common with the fastening curl part. SK-5 is used as the material for this mounting member  1  and elasticity is added by quenching and tempering. A fastening screw  6  is engaged via a washer  5  to fastening curl member  3   a  and this fastening screw  6  is screwed onto the female thread part  1   c  provided in bearing part lb. The modified-bearing hole  4   a  of modified engaging curl part  4  is formed to have a substantially D-like cross-sectional shape having a flat part  4   b  in part. 
     Reference numeral  7  indicates a shaft. SCM415 is used as the material for this shaft  7  and carburization quenching is performed. A mounting part  7   a  of substantially rectangular cross-sectional shape is provided at one end part of shaft  7  and this mounting part  7   a  is inserted into a modified mounting hole  8   a  of substantially rectangular shape that is provided in a bracket  8 , which is mounted to the display unit (opening/closing unit), that is, the second member, and fixed so as not to fall off by a fixing pin  9  that is passed through in the radial direction. This shaft  7  has, in continuation with the mounting part  7   a , a torque generating part  7   g , which is comprised of a main torque generating part  7   b  and a sub torque generating part  7   c , and a flange part  7   f  is formed between main torque generating part  7   b  and sub torque generating part  7   c . Main torque generating part  7   b  is press fitted into fastening curl part  3  and sub torque generating part  7   c  is press fitted into modified engaging curl part  4 . Main torque generating part  7   b  is arranged so that by tightening the fastening screw  6  mounted to fastening curl member  3   a  of fastening curl part  3 , the fastening curl member  3   a  will move towards the bearing plate part  1   b  side and the inner diameter of bearing hole  3   b  thereof will be narrowed, thereby generating the main frictional torque. 
     Grease or other lubricant is applied to the outer circumference of main torque generating part  7   b  and an oil groove  7   d  is provided so as to enable lubrication by this lubricant over a long period of time. An oil groove may be provided on the sub torque generating part as well, and the oil groove  7   d  may be a plurality of oil holes. 
     The shaft&#39;s sub torque generating part  7   c , which is press fitted into modified bearing hole  4   a  of modified engaging curl part  4 , has a substantially D-like cross-sectional shape that is matched with the D-like cross-sectional shape of modified bearing hole  4   a  of modified engaging curl part  4 . The flange part  7   f  of shaft  7  engages with the expanding groove  2 , provided between fastening curl part  3  and modified engaging curl part  4 , to prevent the falling off of shaft  7  from fastening curl part  3  or modified engaging curl part  4  in the axial direction. The shape of sub torque generating part  7   c  and the cross-sectional shape of modified bearing hole  4   a  are not restricted to those of this embodiment. 
     The assembly of the tilt hinge by this invention is thus completed by mounting the mounting member  1  onto the keyboard unit A, which serves as the main device unit, that is, the first member of a compact office automation equipment, such as a compact personal computer, and mounting the mounting bracket  8  onto the display unit (opening/closing unit) B, which is the second member. And when display unit B is opened or closed with respect to keyboard unit A, shaft  7  is rotated via bracket  8 , and in this process, the main frictional torque is generated as mentioned above at main torque generating part  7   b  of shaft  7 , which is fastened by fastening curl part  3 , to enable display unit B to be stopped and maintained with stability at an arbitrary opening angle. 
     In this process, since the flat part  7   e  of the sub torque generating part  7   c  of shaft  7 , which has a D-like cross-sectional shape, generates a weak frictional torque in the opening angle range of 0° to 30° of display unit B due to the positional relationship with flat part  4   b  of modified bearing hole  4   a , which likewise has a D-like cross-sectional shape, the total frictional torque of the frictional torques generated at main torque generating part  7   b  and sub torque generating part  7   c  is made to differ in the opening angle range of 0° to 30° of display unit B and the opening angle range of 30° or more. Thus with the embodiment, display unit B can be opened with relative ease and yet can be closed securely in the closing process. 
     FIGS. 7 through 11 show another embodiment of the tilt hinge for office automation equipment by this invention, and in these drawings, reference numeral  11  indicates a mounting member, which is mounted for example to the keyboard unit C, which is the first member and is the main device unit of an office automation equipment. The mounting member  11  of this embodiment is a die cast member and is comprised of a mounting plate part  11   a  and a bearing plate part  11   b , which is raised perpendicularly from the end part of mounting plate part  11   a . Mounting grooves  11   c  and  11   d , which are shifted in position in the front/rear direction, are provided in the vertical direction of bearing plate part  11   b . This mounting member  11  may also be mounted to the display unit D (opening/closing unit), which is the second member. 
     Engaging curl parts  12  and  13  have their fixing members  12   a  and  13   a  inserted into the mounting grooves  11   c  and  11   d  of bearing plate part lib of mounting member  11  and are fixed by mounting screws  14  to bearing plate part  11   b . These engaging curl parts  12  and  13  are made opposite in the direction of engagement and the fixing members  12   a  and  13   a  are extended downwards at positions that are biased in mutually different directions with respect to the axial centers of the engaging curl parts  12  and  13 , and the directions of mounting of fixing members  12   a  and  13   a  onto mounting grooves  11   c  and lid are differed so that the axial centers of the engaging curl parts  12  and  13  will be mutually matched. 
     With this embodiment, the die cast mounting member  11  may be eliminated, the engaging curl parts  12  and  13  may be made into a single integral body, and the fixing members may be extended and arranged to be fixed to the keyboard unit C, which is the first member. The positions at which the respective fixing members  12   a  and  13   a  extend downwards from modified engaging curl parts  12   d  and  13   d  may also be matched with the axial centers of modified engaging curl parts  12   d  and  13   d.    
     The cross-sectional shapes of modified engaging curl parts  12   d  and  13   d  of the respective engaging curl parts  12  and  13  are not circular holes but flat parts  12   b  and  13   b  are formed at the front end sides of the engaging curl parts so as to form modified bearing holes  12   c  and  13   c.    
     Reference numeral  15  indicates a shaft. This shaft is comprised of an axial part  15   a  of circular cross-sectional shape and a mounting part  15   b  of substantially rectangular shape. Mounting part  15   b  is inserted into the modified mounting hole  16   a , with a substantially rectangular shape, of bracket  16 , and these members are fixed together by a fixing pin  17  that passes through in the radial direction. 
     Especially as shown in FIG. 8, supporting portions  11   f ,  11   f  of the shaft  15  are formed on the top of the bearing plate part  11   b  of the mounting member  11  and part  11   c  and its extension  11   e.    
     Shaft  15  has a flange part  15   c  provided at substantially the central part of the axial part  15   a . Oil grooves  15   d , comprised of inclining circular grooves, are provided so as to differ mutually in the directions of inclination on the left and right torque generating parts  15   e  and  15   f  that are partitioned by flange part  15   c . The portions at which these oil grooves  15   d  are provided are press fitted into the modified bearing holes  12   c  and  13   c  of modified engaging curl parts  12   d  and  13   d  of the respective engaging curl parts  12  and  13 . Oil grooves  15   d  are filled with an unillustrated lubricant, such as grease. 
     Bracket  16  has a stopper part  16   b  protruded from the edge part of the modified mounting hole  16   a  thereof and this stopper part  16   b  is arranged to come in contact with a stopper member  11   e , provided on mounting member  11 , at a certain rotation angle. 
     Thus as shown in FIG. 11, since the points at which the outer circumferences of torque generating parts  15   e  and  15   f  of axial part  15   a  of the press-fitted shaft  15  contact the modified bearing holes  12   c  and  13   c  of modified engaging curl parts  12   d  and  13   d  of engaging curl parts  12  and  13  are limited to the points E and the opposite surfaces F, the spring characteristics are stabilized and the spring constant is therefore limited to a low value. As a result, even when the modified engaging curl parts  12   d  and  13   d  of engaging curl parts  12  and  13  are not made strict in precision in comparison to the prior arts, a fixed frictional torque without dispersion can be created. 
     Also as shown likewise in FIG. 11, since gaps G are formed between the modified bearing holes  12   c  and  13   c  of the respective engaging curl parts  12  and  13  and the torque generating parts  15   e  and  15   f  of axial part  15   a  of shaft  15 , oil basins for a lubricant are formed naturally at these gaps G, eliminating the necessity for using a collar as in the prior art. 
     Furthermore, further lubrication can be promoted by providing oil grooves  15   d  in the portions of torque generating parts  15   e  and  15   f  of axial part  15   a  as shown in FIG.  8 . The shape and arrangement of the oil grooves  15   d  to be provided in the torque generating parts  15   e  and  15   f  of axial part  15   a  of shaft  15  are not limited to those of this embodiment and may be a plurality of indented parts. 
     For assembly of the tilt hinge by this invention, first the axial part  15   a  of shaft  15  is press fitted into modified bearing holes  12   c  and  13   c  of the modified engaging curl parts  12   d  and  13   d  of the respective engaging curl parts  12  and  13  until contact is made with flange part  15   c  from both sides of shaft  15  and the fixing members  12   a  and  13   a  of the respective engaging curl parts  12  and  13  are then inserted into the mounting grooves  11   c  and  11   d  and fixed to mounting member  11  by means of mounting screws  14 . The mounting of bracket  16  onto shaft  15  may be performed before or after the mounting of engaging curl parts  12  and  13  onto mounting member  11 . In the case where there are a plurality of engaging curl parts  12  and  13  that are made integral in their fixing parts, the flange part  15   c  of shaft  15  is eliminated and an E-ring is used. 
     The modified engaging curl part may be provided at just one side of the engaging curl part. Also, one of the engaging curl parts  12  and  13  of the second embodiment may be used as the fastening curl part of the first embodiment. Shafts  7  and  15  may be used as rotating shafts, and in such cases, the mounting member  1  or  11  and bracket  8  or  16  of the first or second embodiment rotate in a relative manner with shaft  7  or  11  as the pivot.