Abstract:
There is provided an engagement device allowing two members to readily engage with each other at a position as desired by the user. A bracket has a left end provided with a fixed protrusion, and a right end provided with a vertically movable lever having a groove obliquely traversing both of the vertical and horizontal directions. When the lever is pushed downward, a Z-letter piece moves leftward relative to the bracket&#39;s lower portion. While the lever is pushed with a member desired to be attached to the bracket engaging with a left end of the bracket, a right engaging feature of the member is engaged with a right protrusion of the Z-letter piece.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to engagement devices engaging two members and particularly to such compact engagement devices. 
     2. Description of the Related Art 
     FIGS. 6A and 6B show a structure of an engagement device engaging two members relating to the present invention. FIG. 6A is a perspective view of an interface unit  40  to which an information terminal  41  corresponding to one member is to be mounted, although an information terminal  41  corresponding to the other member has not yet been mounted thereto. FIG. 6B shows interface unit  40  with information terminal  41  mounted thereto. Information terminal  41  and interface unit  40  are interconnected via a connection terminal  42 . 
     FIGS. 7A-7C are cross sections more specifically showing how interface unit  40  and information terminal  41  are interconnected. FIG. 7A is a cross section of a main portion of information terminal  41 . FIG. 7B is a cross section of a main portion of interface unit  40 . FIG. 7C is a cross section showing that information terminal  41  is mounted to interface unit  40 . 
     Referring to FIG. 7A, information terminal  41 , not yet mounted to interface unit  40 , has a movable contact  52  biased by a spring  54  and thus out of contact with an electrical contact  51  provided internal to information terminal  41 . 
     Referring to FIGS. 6A and 6B and  7 A- 7 C, to mount information terminal  41  to interface unit  40 , a set button  43  as shown in FIG. 6A is initially pressed. Thus, as shown in FIG. 7B, the interface unit&#39;s connecting terminal  42  moves in a direction indicated by the arrow. With connecting terminal  42  moving as described above, information terminal  41  is positioned in interface unit  40  on a bottom surface  44 . When set button  43  is released with the terminal thus positioned, as shown in FIG. 7C the interface unit&#39;s connecting terminal  42  moves in the direction indicated by the arrow to push and thus bring movable contact  52  of information terminal  41  into contact with an electrical contact  51  of the body of information terminal  41  to allow signal communication therebetween. 
     There is a heart rate meter worn by joggers and swimmers conventionally on their arms and transmitting the user&#39;s heart rate signal from a sensor to the heart rate meter wirelessly. 
     If the user desires to use the heart rate meter when riding a bicycle as well as jogging and swimming, the heart rate meter is attached to the bicycle&#39;s handle or the like. This would not particularly be problematic if the bicycle&#39;s speed signal, the crank shaft&#39;s rotation signal and the like as well as the user&#39;s heart rate signal are transmitted to and received from the heart rate meter wirelessly. If any signal generated from the bicycle is transmitted and received via a wire, however, their interface contacts electrically conduct due to the user&#39;s skin, water and the like, resulting in erroneous operation. 
     To avoid this, it is preferable that normally an external contact and an internal interconnection be disconnected from each other and only as required the external contact and the internal interconnection be connected with each other by the above-described structure connecting interface unit  40  and information terminal  41  together. With such structure, however, interface unit  40  serving as a base is too large in size and it can thus not be mounted on a small space such as a bicycle&#39;s handle. 
     SUMMARY OF THE INVENTION 
     The present invention therefore contemplates an engagement device capable of readily engaging two members, such as a base unit and a measuring instrument, at a position as desired by the user. 
     In accordance with the present invention, an engagement device overlaps and thus engages first and second members with each other. The first member has one end provided with a fixed, first engaging feature, and the other end provided with a second engaging feature movable in a first direction corresponding to a direction towards one end of the first member. The second member has third and fourth engaging features engaging with the first and second engaging features, respectively. The first member has a lever moving the second engaging feature in the first direction when the second engaging feature engages with the fourth engaging feature. With the first member overlapping the second member, in a portion other than the lever the first member has a region smaller than the second member. 
     With the engagement device of the present invention, when the first and second members overlap, in a portion other than the lever for moving the second engaging feature in the first direction the first member occupies an area smaller than the second member. This allows the engagement device to be compact. As a result, there can be provided a device capable of readily connecting together two members, such as a base unit and a measuring instrument, at a position as desired by the user. 
     Preferably the lever is movable in a second direction traversing the first direction. 
     Still preferably the lever is biased in a direction opposite to the second direction. 
     Still preferably the second engaging feature has a portion obliquely traversing both of the first and second directions and the lever slides along the oblique portion to move in the first direction. 
     The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a heart rate meter with the present invention applied thereto. 
     FIG. 2 is a schematic view of a bicycle with an engagement device of the present invention applied thereto. 
     FIGS. 3A-3C show a configuration of a heart rate meter corresponding to one member with an engagement device of the present invention applied thereto. 
     FIGS. 4A-4E show a configuration of a bracket corresponding to the other member. 
     FIGS  5 A- 5 D show a process for connecting a heart rate meter and a bracket together. 
     FIGS. 6A and 6B show one example of a conventional engagement device. 
     FIGS. 7A-7C are cross section of a conventional engagement device. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Hereinafter one embodiment of the present invention will be described with reference to the drawings. 
     Referring to FIG. 1, a measuring instrument to which an engagement device of the present invention applied is shown exemplarily in the form of a heart rate meter  10 . Heart rate meter  10  is fit on a user&#39;s arm normally with a belt  18 . 
     FIG. 2 shows heart rate meter  10  connected to a bracket  20  attached to the handle of a bicycle  30 , rather than a user&#39;s arm. Bicycle  30  has a front wheel  36  provided with a speed-signal transmit unit  32  detecting the front wheel&#39;s rotation to transmit the bicycle&#39;s speed signal. 
     Bicycle  30  has a rear wheel  37  provided with a cadence signal transmit unit  33  transmitting information on the transmission gears of bicycle  30 . Speed-signal transmit unit  32  and cadence signal transmit unit  33  output their respective signals which are in turn transmitted via a cable to bracket  20  attached to the bicycle&#39;s handle. 
     The user wears a heart rate signal transmit unit  34  detecting the user&#39;s heart rate and transmitting a signal corresponding thereto. The heart rate signal from heart rate signal transmit unit  34  is transmitted wirelessly to heart rate meter  10 . 
     As has been described above, when a user does not ride bicycle  30  the user wears heart rate meter  10  on the user&#39;s arm, attached with belt  18 . When the user rides bicycle, heart rate meter  10  is attached to bracket  20  attached to the bicycle&#39;s handle. When heart rate meter  10  is attached to bracket  20 , heart rate meter  10  also receives the speed and cadence signals from bicycle  30  and displays signals other than a heart rate signal on a display unit (not shown). 
     Thus the user can refer to the display on heart rate meter  10  to adjust the bicycle&#39;s speed, gear-ratio and the like. 
     An engagement device of the present invention is implemented at a connection between heart rate meter  10  and bracket  20  and will now be described in greater detail. 
     FIGS. 3A-3C show a general configuration of heart rate meter  10 . FIG. 3A is a plan view of heart rate meter  10 , as seen at a back side thereof engaged with bracket  20 . FIG. 3B is a cross section thereof, taken along a line IIIB—IIIB of FIG.  3 A. FIG. 3C is a cross section thereof, taken along a line IIIC—IIIC of FIG.  3 A. 
     As shown in FIG. 3A-3C, heart rate meter  10  has a back side provided with two movable contacts  12  which allow bracket  20  and heart rate meter  10  to communicate an electrical signal. On the heart rate meter&#39;s back side, a receiving plate  16  is also attached having opposite ends provided with features  15   a  and  15   b  engaging with bracket  20 . Engaging features  15   a  and  15   b,  as shown in FIGS. 3A and 3B, expand on the back side of heart rate meter  10  along the belt thereof and have openings  17   a,    17   b  adjacent to their respective ends. 
     Referring to FIG. 3C, heart rate meter  10  includes a movable contact  12  biased by a spring  14  outwardly of heart rate meter  10 , a rubber conductor sit on movable contact  12 , and a printed circuit board  11  which is mounted, spaced from the rubber conductor, and corresponds to an internal circuit of heart rate meter  10 . Movable contact  12  receives a signal from printed circuit board  11  and that from the bracket  20  side. While the figures show two such movable contacts  12  provided, any number of movable contacts  12  may be used. 
     FIGS. 4A-4E show a configuration of bracket  20 . FIG. 4A is a plan and partially broken view of the bracket&#39;s lower portion  21  on a side to which heart rate meter  10  is to be mounted. FIG. 4B is a cross section taken along a line indicated by an arrow IVB—IVB of FIG.  4 A. FIG. 4C is a cross section taken along a line indicated by an arrow IVC—IVC of FIG.  4 A. FIG. 4D is a view, as compared with the FIG. 4A broken view, showing how the lower portion  21  movable portion can move when heart rate meter  10  engages with the bracket&#39;s lower portion  21 . FIG. 4E is a view corresponding to a right end of FIG. 4B, although in the position as shown in FIG.  4 D. It should be noted that a broken view shown in FIG. 4A is a view taken along line IVA of FIG.  4 B. 
     Bracket  20  is attached to the handle of bicycle  30  with a fixing member (not shown). 
     As shown in FIGS. 4A-4E, bracket  20  includes a lower portion  21  and an upper portion  22  provided at a front side of lower portion  21 . Upper portion  22  has a bracket contact  23  connected to movable contact  12  of heart rate meter  10 . Lower portion  21  has one end with an end  24   a  lifted higher than a flat portion  22   a  of upper portion  22 . End  24   a  has a protrusion  25   a  at the left-hand end  24   a  side of lower portion  21 . Protrusion  25   a  has a lower portion mating with engaging feature  15   a  of heart rate meter  10 . End  24   a  has a support  40  via which lower portion  21  supports end  24   a.    
     The bracket&#39;s lower portion  21  has a right end as described below: Bracket  20  has a right end provided with a lever  26  movable in the Y direction as shown in FIG.  4 A. Lever  26  has a lower end biased by a spring  27  to protrude from lower portion  21 . Lever  26  has a groove  28  oblique with respect to both of the X and Y directions in the figure. Engaging with groove  28 , a Z-letter piece  29  is fit. Z-letter piece  29  as shown in FIG. 4A has a Z-letter shape as seen in the Y direction. Along the lever&#39;s groove  23  moves a side of Z-letter piece  29  that is oblique with respect to the X and Y directions. More specifically, when lever  26  is pushed in the Y direction downward, Z-letter piece  29  moves relative to the bracket&#39;s lower portion  21  in the X direction to the left. 
     Referring to FIGS. 4B and 4E, Z-letter piece  29  has an end  24   b  similar to left end  24   a,  having a protrusion  25   b  in the X direction at the bracket&#39;s right side. When Z-letter piece  29  moves in the X direction to the left, protrusion  25   b  mates with engaging feature  15   b  through opening  17   b  of heart rate meter  10 . 
     FIGS. 5A-5D show how heart rate meter  10  is attached to bracket  20  step by step. FIG. 5A is a rear view of bracket  20  with heart rate meter  10  overlapping and thus mounted thereon, as seen at a back side thereof, and FIGS. 5B-5D are cross sections taken along line V—V of FIG.  5 A. 
     As shown in FIG. 5B, the heart rate meter&#39;s engaging feature  15   a  initially engages with protrusion  25   a  of one end  24   a  of the bracket&#39;s lower portion  21 . Then, by pushing lever  26 , Z-letter piece  29  corresponding to the right end of the bracket&#39;s lower portion  21  moves in the X direction, as shown in FIG.  4 D. In this condition, engaging feature  15   b  engages with the other end  24   b  of Z-letter piece  29  (FIG.  5 D). When lever  26  is released with such engagement achieved, spring  27  causes biased lever  26  to return upwards. This ensures the bracket&#39;s right end  25  mates with the heart rate meter&#39;s right engaging feature  15   b.    
     When such engagement is achieved, the bracket&#39;s bracket contact  23  pushes the heart rate meter&#39;s movable contact  12  and rubber conductor  13  placed thereon. Consequently, rubber conductor  13  can be brought into contact with printed circuit board  11  to allow signal communication therebetween. 
     Although the present invention has been described and illustrated in detail, it is clearly understood that the same is by way of illustration and example only and is not to be taken by way of limitation, the spirit and scope of the present invention being limited only by the terms of the appended claims.