Patent Publication Number: US-7712695-B2

Title: Spool braking device for fishing reel

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a spool braking device for a double bearing reel. 
     A typical double bearing reel includes a reel body, which is attached to a fishing rod, and a line winding spool, which is attached to the reel body in a rotatable manner. When used by a person, such as a beginner, who is not accustomed to a double bearing reel (hereinafter referred to as “reel”), a backlash may be produced when casting the fishing line. 
     Normally, backlash is produced when the spool rotates at a speed that is higher than the speed at which the fishing line is drawn out of the spool (hereinafter referred to as “line speed”). More specifically, when the spool rotation speed exceeds the line speed, the spool overly continues to rotate even after the fishing line hits water. This entangles the fishing line in the spool. 
     To prevent such backlash, for example, U.S. Pat. No. 5,833,156 discloses an automatic brake system controlled by a microcomputer. The automatic brake system includes a rotation detector, which detects the rotation speed of the spool, an acceleration sensor, which detects the line speed, and a brake mechanism, which uses magnetic force to control the rotation speed of the spool. When the spool rotation speed exceeds the line speed, the microcomputer drives the brake mechanism and increases the spool braking force. The microcomputer also determines when the fishing line will hit water from a detection value of the line speed to apply full braking on the spool. 
     However, in the above-described prior art that controls the braking of the spool just by detecting the line speed and the spool rotation speed, there is a limit to the braking capability. Particularly, in the prior art, the acceleration sensor is connected to the fishing line. Accordingly, the acceleration sensor detects the line speed only when the fishing line is being cast. Further, there is another example in the prior art in which a height sensor is used in lieu of the acceleration sensor. However, the height sensor also detects only the line speed. Thus, in each prior art example, spool braking is performed only when the spool rotation speed exceeds the line speed or when the fishing line hits water (i.e., line speed becomes zero). Further, in the prior art, the braking timing for when the fishing line hits water is determined from the detection of the line speed. Therefore, backlash prevention control is performed after the fishing line actually hits water. This slightly delays the timing in which backlash prevention control is actually performed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention, together with objects and advantages thereof, may best be understood by reference to the following description of the presently preferred embodiments together with the accompanying drawings in which: 
         FIG. 1  is a schematic diagram entirely showing a preferred embodiment of a fishing device according to the present invention; 
         FIG. 2  is a schematic block diagram of a spool braking device for the fishing device of  FIG. 1 ; 
         FIG. 3  is a schematic flowchart illustrating a spool brake control executed in the preferred embodiment; 
         FIG. 4  is a flowchart illustrating in detail a swing monitoring process (step  200 ) of  FIG. 3 ; 
         FIG. 5  is a flowchart illustrating in detail a control parameter calculating process (step  300 ) of  FIG. 3 ; and 
         FIG. 6  is a flowchart illustrating in detail a spool braking process (step  400 ) of  FIG. 3 . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     In the drawings, like numerals are used for like elements throughout. 
     The present invention provides a spool braking device and a spool braking method that increases spool braking capability. 
     One aspect of the present invention is a spool braking device for a fishing reel attached to a fishing rod in a detachable manner for use with a fishing line. The spool braking device includes a rotatable spool arrangeable in the reel for winding with the fishing line. A brake mechanism electronically brakes rotation of the spool. An acceleration sensor detects swing acceleration produced when the fishing rod is swung and generates an acceleration signal. A brake control unit drives the brake mechanism. The brake control unit determines whether or not to brake the spool based on the acceleration signal. 
     A further aspect of the present invention is a fishing device for use with a fishing line. The fishing device includes a fishing rod and a fishing reel attached to the fishing rod in a detachable manner. The fishing rod includes an acceleration sensor for detecting swing acceleration produced when the fishing rod is swung and generating an acceleration signal. The reel includes a spool for winding the fishing line, a brake mechanism for electronically braking rotation of the spool, and a brake control unit for driving the brake mechanism. The brake control unit determines whether or not the spool needs to be braked based on the acceleration signal. 
     Another aspect of the present invention is a method for controlling braking of a rotatable spool arranged in a fishing reel. The reel is attached to a fishing rod in a detachable manner, and the reel includes a brake mechanism for electronically braking rotation of the spool. The method includes generating an acceleration signal using an acceleration sensor to detect swing acceleration produced when the fishing line is swung, and driving the brake mechanism by determining whether or not to brake the spool based on the acceleration signal. 
     Other aspects and advantages of the present invention will become apparent from the following description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the invention. 
     A fishing device  10  equipped with a preferred embodiment of a spool braking device according to the present invention will hereinafter be discussed with reference to the drawings.  FIG. 1  is a schematic diagram entirely showing the fishing device  10 , which includes a fishing rod (hereinafter referred to as “rod”)  12  and a double bearing reel (hereinafter referred to as “reel”)  14 . The reel is attached to the rod  12  in a detachable manner. 
     Referring to  FIG. 1 , the reel  14  is attached to a basal portion  22  of the rod  12 . A power supply terminal and a communication terminal (not shown) are incorporated in the basal portion  22  of the rod  12 . 
     An acceleration sensor  32  is arranged at a distal portion  24  of the rod  12 . When the reel  14  is attached to the rod  12 , a power supply device (not shown), which is arranged in the reel  14 , supplies power to the acceleration sensor  32  via the power supply terminal. The acceleration sensor  32  is preferably a tri-axial capacitance type acceleration sensor, which detects acceleration in the directions of an x-axis, y-axis, and z-axis. The acceleration sensor  32  is connected to the control system in the reel  14  by a signal wire (not shown), which extends through a rod body  26 . 
     The reel  14  includes a reel body  42 , a rotatable spool  44  arranged on the reel body  42 , a microcomputer  46  ( FIG. 2 ) incorporated in the reel body  42 , a rotation sensor  48  ( FIG. 2 ) for detecting rotation of the spool  44 , and a brake mechanism  50  ( FIG. 2 ) for electronically braking rotation of the spool  44 . The reel  14  also includes a user interface  52  ( FIG. 2 ) for setting the operation of the microcomputer  46 . Although not shown, the reel  14  also includes a handle for manually rotating the spool  44 , a clutch lever for selectively switching the spool  44  between a free state and a locked state  4 , and a mechanical brake for adjusting the rotation degree of the spool  44 . 
     A fishing line  16  is wound around the spool  44 . The fishing line  16  has a basal end fixed to the spool  44  and a distal end (free end) drawn out of the spool  44 , and guided to the distal end of the rod  12  through a group of guides  18  arranged on the rod  12 . As shown in  FIG. 1 , a weight  20  such as lure is attached to the distal end of the fishing line  16  drawn out of the rod  12 . 
       FIG. 2  is a schematic block diagram showing a spool braking device  60  in the preferred embodiment. The microcomputer  46  includes a memory  62  and a timer  64 . The memory  62  stores a spool braking program, which contains a group of commands executable by the microcomputer  46 , and a group of initial parameters used by the microcomputer  46  when executing the program. The memory  62  also stores a group of control parameters obtained by the microcomputer  46  when executing the program. The microcomputer  46  executes the spool braking program and uses acceleration information from the acceleration sensor  32  to drive the brake mechanism  50 . In addition to the acceleration information from the acceleration sensor  32 , the microcomputer  46  may use rotation information from the rotation sensor  48  when driving the brake mechanism  50 . Accordingly, the microcomputer  46  functions as a brake control unit. The microcomputer  46  also uses the acceleration information to calculate an estimated casting distance Xd, which is the distance from a casting point where the user casts the fishing line  16  (including the weight  20 ) to a landing point where the fishing line  16  lands on water (hereinafter referred to as “landing point”). Based on the estimated casting distance Xd, the microcomputer  46  drives the brake mechanism  50 . 
     The rotation sensor  48  detects rotation of the spool  44  and generates a rotation signal Sr. A magnetic sensor, an optical sensor, or the like may be used as the rotation sensor  48 . The microcomputer  46  determines the rotation speed Vs of the spool  44  based on the rotation signal Sr from the rotation sensor  48 . The spool rotation speed Vs relates to the actual cast amount of the fishing line  16  drawn out of the spool  44 . 
     The brake mechanism  50  electronically brakes rotation of the spool  44  in response to a drive control signal Sd from the microcomputer  46 . The magnet brake mechanism  50  may be formed by a plurality of magnets that apply magnetic torque to the spool  44  to adjust the rotation speed. 
     When the user swings the rod  12 , the acceleration sensor  32 , which is arranged at the distal portion  24 , detects the swing acceleration and generates an acceleration signal Sa. When the fishing line  16  is cast, the microcomputer  46  monitors the user&#39;s swing motion based on the acceleration signal Sa from the acceleration sensor  32 . During the casting, the microcomputer  46  calculates a plurality of control parameters, which include an initial speed V 0 , projection angle θ, spool rotation initiation period Ts, estimated line speed V L , estimated cast line amount D L , and estimated casting distance Xd of the fishing line  16  (including the weight  20  such as lure) based on the monitor result. The initial speed V 0  is the speed the fishing line  16  (weight  20 ) is cast from the rod  12  when the rod is located at a casting swing termination position. The projection angle θ is the angle at which the fishing line  16  (weight  20 ) is cast from the rod  12  at the casting swing termination position. The spool rotation initiation period Ts is the expected period from when the casting swing of the rod  12  is terminated to when the spool  44  starts to rotate. The estimated line speed V L  is the estimated speed of the fishing line  16  that is being cast. The estimated cast line amount D L  is the estimated cast amount of the fishing line  16  drawn out of the spool  44  at the estimated line speed V L . The estimated casting distance Xd is the casting distance of the fishing line  16  from the casting point to the landing point. 
     The user interface (hereinafter referred to as “UI”)  52  includes a reset button  54  for initializing the operation of the microcomputer  46 . When the user pushes the reset button  54 , the microcomputer  46  resets output information (Sa, Sr) of the acceleration sensor  32  and the rotation sensor  48 . Further, when the reset button  54  is pushed, the microcomputer  46  stores in the memory  62  the height level of the rod  12  as water surface level Yw (e.g., “0”). 
     The UI  52  further includes a plurality of parameter switches  56  manually operated by the user to input and set the group of initial parameters. The user may change the casting conditions (i.e., initial parameter group) by operating the parameter switches  56 . Accordingly, the UI  52  serves as a parameter setting unit. In the preferred embodiment, the UI  52  includes three parameter switches  56  for setting a height parameter C 1 , a mass parameter C 2 , and a weather parameter C 3 , respectively. Although not shown in the drawings, the UI  52  also includes a start button. 
     The height parameter C 1  indicates the height (hereinafter referred to as “initial height”) of the distal portion  24  of the rod  12  from the water surface level Yw when the rod  12  is located at the casting swing termination position. That is, the initial height is the height level of the rod  12  when the fishing line  16  is cast from the rod  12 . The parameter switch  56  for setting the height parameter C 1  may be configured so as to enable the initial height to be set at any value or to enable adjustment of the initial height in fixed steps. 
     The mass parameter C 2  indicates the mass of the weight  20  attached to the fishing line  16 . The parameter switch  56  for setting the mass parameter C 2  may be configured so as to enable the mass of the weight  20  to be set at any value or to enable adjustment of the mass in fixed steps. 
     The weather parameter C 3  indicates weather conditions such as the wind direction, wind speed, weather, and the like. In the preferred embodiment, the microcomputer  46  recognizes the weather parameter C 3  as an air resistance coefficient. The parameter switch  56  for setting the weather parameter C 3  includes a plurality of preset buttons. When the user pushes a predetermined preset button that corresponds to the weather condition (sunny, rain, wind speed, wind direction, or the like), an air resistance coefficient corresponding to the pushed preset button is stored in the memory  62 . 
     The operation of the spool braking device  60  will now be discussed with reference to  FIGS. 3 to 6 .  FIG. 3  is a flowchart summarizing the spool brake control. 
     Before starting step  100 , the user initializes the spool braking device  60  as described below. 
     (A) The rod  12  is held at a position (e.g., ground surface) that is substantially the same height as the water surface, and the reset button  54  is pushed to set the water surface level Yw (“0”) in the microcomputer  46 . 
     (B) The parameter switches  56  are operated to set the initial parameters (i.e., height parameter C 1 , mass parameter C 2 , and weather parameter C 3 ) in the microcomputer  46 . 
     (C) The start button of the microcomputer  46  is pushed (this operation may be omitted). 
     In step  100 , the microcomputer  46  reads the initial parameters C 1 , C 2 , and C 3  from the memory  62  when the user pushes the start button. 
     In step  200 , the microcomputer  46  monitors the user&#39;s swing motion with the acceleration sensor  32 . 
     In step  300 , based on the monitoring result of the swing motion, the microcomputer  46  calculates the control parameters (i.e., initial speed V 0 , projection angle θ, spool rotation initiation period Ts, estimated line speed V L , estimated cast line amount D L , estimated casting distance Xd) used for executing brake control on the spool  44 . 
     In step  400 , the microcomputer  46  performs a spool braking process, which includes backlash prevention control, based on the calculated control parameters. Step  400  is continuously performed until the spool rotation speed Vs becomes zero. When step  400  is completed, the spool brake control ends, and the user starts fishing. 
       FIG. 4  is a flowchart showing the swing monitoring process of step  200  in detail. In step  210 , the microcomputer  46  determines a casting swing initiation position P 1  of the rod  12  from the acceleration signal Sa and stores the position P 1  in the memory  62 . For example, when the direction of the user facing the casting point is the positive direction, acceleration in the negative direction shifts from a positive value to zero at the position where the user stops the casting swing of the rod  12 . Therefore, the microcomputer  46  recognizes the position P 1  when detecting a change in acceleration in the negative direction. 
     In step  220 , the microcomputer determines a casting swing termination position P 2  of the rod  12  from the acceleration detection signal Sa and stores the position P 2  in the memory  62 . Specifically, when the rod  12  reaches the casting swing termination position P 2 , acceleration in the positive direction shifts from a positive value to zero. Therefore, the microcomputer  46  recognizes the position P 2  by detecting a change in acceleration in the positive direction. 
     In step  230 , the microcomputer  46  stores in the memory  62  swing accelerations (Sa) for the X, Y, and Z directions sampled during a swing period in which the rod  12  was swung from position P 1  to position P 2 . Specifically, the microcomputer  46  samples accelerations for the X, Y, and Z directions in extremely short time cycles (e.g., several milliseconds) during the swing period and stores in the memory  62  the accelerations sampled in each cycle. Accordingly, the memory  62  stores each of the sampled accelerations for the X, Y, and Z directions during the swing period in which the rod  12  is swung from position P 1  to position P 2 . 
       FIG. 5  is a flowchart showing the control parameter calculation process of step  300  in detail. In step  310 , the microcomputer  46  uses all of the sampled accelerations stored in the memory  62  to calculate the initial speed V 0  and the projection angle θ. As known in the art, speed is obtained by integrating acceleration. In the preferred embodiment, the microcomputer  46  calculates the speed for each cycle from the corresponding sampled accelerations and the speed of the previous cycle. The same calculation is repeated for each cycle until obtaining the speed at the position P 2  (i.e., initial speed V 0 ). The microcomputer  46  then calculates the projection angle θ based on the calculated initial speed V 0  in the X, Y, and Z directions. Calculations are not limited in such a manner, and the microcomputer  46  may obtain the initial speed V 0  by calculating the speed in real time for every sampling cycle. 
     In step  320 , the microcomputer  46  calculates the spool rotation initiation period Ts based on the initial speed V 0  and the spool rotation speed Vs. Specifically, the microcomputer  46  sets as a reference time (“0”) the time when the casting swing termination position P 2  is detected. Then, the microcomputer  46  estimates the period from the reference time until when the spool  44  starts to rotate (i.e., Vs&gt;0) based on the initial speed V 0 . When the weight  20  is connected to the fishing line  16  at a distance of about 15 to 20 cm from the distal end of the rod  12 , and the initial speed V 0  is 50 km/h (1.3 mm/mS), the microcomputer  46  calculates the spool rotation initiation period Ts as being about 115 to 154 mS. That is, the microcomputer  46  predicts that the spool  44  will start to rotate after about 115 to 154 mS from the reference time. Accordingly, although not shown in the drawings, the microcomputer  46  determines that a casting error has occurred if rotation of the spool  44  (Vs&gt;0) is not detected after time Ts elapses. In such a case, the microcomputer  46  performs spool braking. The spool rotation initiation period Ts may include a margin. 
     In step  330 , the microcomputer  46  uses the two control parameters calculated in step  310  (initial speed V 0  and projection angle θ) and three initial parameters (height parameter C 1 , mass parameter C 2 , and weather parameter C 3 ) to calculate the estimated casting distance Xd from equations 1 and 2. 
     
       
         
           
             
               
                 
                   Xd 
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                   Yw 
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     Here, g represents the gravitational acceleration and t represents the elapsed casting time. By using equations 1 and 2, the microcomputer  46  can calculate the estimated casting distance Xd between where the fishing line  16  (weight  20 ) is cast to where the fishing line  16  lands on water (i.e., the water surface level Yw is to be zero) irrespective of time t. In equations 1 and 2, the mass parameter C 2  and the weather parameter C 3  are used as air resistance parameters. If such air resistance parameters (C 2  and C 3 ) are not taken into consideration, the microcomputer  46  may simply calculate the estimated casting distance Xd from equations 3 and 4. 
     
       
         
           
             
               
                 
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     In step  340 , the microcomputer  46  measures the elapsed casting time t with the timer  64 . Further, the microcomputer  46  uses the initial speed V 0 , the projection angle θ, the initial parameters (C 2  and C 3 ), and the elapsed casting time t to obtain the estimated line speed V L  from the following equation 5. 
     
       
         
           
             
               
                 
                   
                     V 
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     The calculation of the estimated line speed V L  is continuously performed throughout the casting period. If the air resistances (C 2  and C 3 ) are not taken into consideration, the microcomputer  46  can simply calculate the estimated line speed V L  from the following equation 6.
 
 V   L = V   0  cos θ  [Equation 6]
 
     In step  350 , the microcomputer  46  obtains the estimated cast line amount D L  (D L =V L ×t) using the calculated estimated line speed V L  and the elapsed casting time t. The calculation of the estimated cast line amount D L  is also continuously performed over the casting period. 
       FIG. 6  is a flowchart showing the spool braking process of step  400  in detail. First, in step  410 , the microcomputer  46  determines whether or not the estimated casting distance Xd is greater than or equal to a minimum casting distance Xmin corresponding to the initial speed V 0  (current calculated value). For example, if the estimated casting distance Xd is extremely short even though the initial speed V 0  is high, the probability of a casting error occurring is high. Factors causing such a casting error include the projection angle θ being too small. Accordingly, the minimum casting distance Xmin corresponding to the initial speed V 0  is stored in the memory  62  of the microcomputer  46  as a first threshold value. A minimum casting distance Xmin may be set for each initial speed V 0 . Alternatively, minimum casting distances Xmin may be set in a stepped manner with each corresponding to a plurality of initial speeds within a predetermined range. In step  410 , if the estimated casting distance Xd is less than the minimum casting distance Xmin that corresponds to the initial speed V 0 , the microcomputer  46  executes brake control (step  470 ). Otherwise, the microcomputer  46  proceeds to step  420 . 
     In step  420 , the microcomputer  46  determines whether or not the projection angle θ is less than or equal to a maximum projection angle θmax corresponding to the initial speed V 0  (current calculated value). That is, if the projection angle θ is extremely large even though the initial speed V 0  is high, the probability of a casting error occurring is high. Accordingly, the maximum projection angle θmax corresponding to the initial speed V 0  is stored in the memory  62  of the microcomputer  46  as a second threshold value. A maximum projection angle θmax may be set so for each initial speed V 0 . Alternatively, maximum projection angles θmax may be set in a stepped manner with each corresponding to a plurality of initial speeds within a predetermined range. In step  420 , if the projection angle θ is greater than the maximum projection angle θmax that corresponds to the initial speed V 0 , the microcomputer  46  executes brake control (step  470 ). Otherwise, the microcomputer  46  proceeds to step  430 . 
     In step  430 , the microcomputer  46  determines the spool rotation speed Vs based on the rotation signal Sr from the rotation sensor  48 . 
     In step  440 , the microcomputer  46  determines whether or not the estimated cast line amount D L  has become equal to the estimated casting distance Xd. If the estimated cast line amount D L  has become equal to the estimated casting distance Xd, the microcomputer  46  determines that the fishing line  16  has landed on water and executes brake control on the spool  44  (step  470 ). That is, the microcomputer  46  executes backlash prevention control based on the estimated cast line amount D L  and the estimated casting distance Xd. The microcomputer  46  proceeds to step  450  if the estimated cast line amount D L  is less than the estimated casting distance Xd. 
     In step  450 , the microcomputer  46  determines whether or not the spool rotation speed Vs is greater than the estimated line speed V L . If the spool rotation speed Vs is greater than the estimated line speed V L , the microcomputer  46  performs the brake control (step  470 ). Otherwise, the microcomputer  46  proceeds to step  460 . 
     In step  460 , the microcomputer  46  determines whether or not the spool rotation speed Vs is zero. If the spool rotation speed Vs is zero, the microcomputer  46  terminates further processing (brake control). Otherwise, the microcomputer  46  returns to step  430 . The microcomputer  46  then repeats step  430  to step  460  until the spool rotation speed Vs becomes zero. 
     The spool braking device  60  of the preferred embodiment has the advantages described below. 
     The microcomputer  46  uses estimates based on the swing acceleration of the rod  12  to determine whether or not the spool  44  needs to be braked. This avoids delays in the brake timing. 
     The acceleration sensor  32  is arranged at the distal portion  24  of the rod  12 . This enables the swing acceleration of the rod  12  to be accurately detected. 
     The time until the fishing line  16  lands on water is predicted from the estimated casting distance Xd. This prevents delays in execution of the backlash prevention control. 
     The microcomputer  46  calculates from the swing acceleration of the rod  12  the plurality of control parameters (initial speed V 0 , projection angle θ, spool rotation initiation period Ts, estimated line speed V L , estimated cast line amount D L , estimated casting distance Xd) for performing spool braking. Accordingly, the spool braking capability is improved with the use of a single acceleration sensor  32 . 
     The microcomputer  46  drives the brake mechanism  50  when the estimated casting distance Xd is less than the minimum casting distance Xmin that corresponds to the initial speed V 0  or when the projection angle θ is greater than the maximum projection angle θmax that corresponds to the initial speed V 0 . Accordingly, the microcomputer  46  can perform spool braking while monitoring the casting of the fishing line  16 . 
     The height parameter C 1  indicating the initial height when the fishing line  16  is cast is set in the microcomputer  46 . This increases accuracy for calculation of the estimated casting distance Xd. 
     The mass parameter C 2  indicating the mass of the weight  20  and the weather parameter C 3  indicating the weather condition are also set in the microcomputer  46 . Thus, the air resistance that is taken into consideration increase accuracy for calculating the estimated casting distance Xd. 
     It should be apparent to those skilled in the art that the present invention may be embodied in many other specific forms without departing from the spirit or scope of the invention. Particularly, it should be understood that the invention may be embodied in the following forms. 
     The microcomputer  46  that executes the software is preferably employed as the brake control unit. However, hardware such as ASIC may be employed as the brake control unit. 
     The acceleration sensor  32  is most preferably arranged at the distal portion  24  of the rod  12  but may be arranged at the central part (rod body  26 ) of the rod  12 . Alternatively, the acceleration sensor  32  may be arranged at the basal portion  22  of the rod  12  or in the reel  14 . However, the detection accuracy of the swing acceleration increases when arranging the acceleration sensor  32  at positions closer to the distal portion of the rod  12 . 
     The initial parameters may include a shape parameter indicating the shape of the weight  20  (e.g., lure shape). The shape of the weight  20  affects the air resistance. Accordingly, use of the shape parameter would increase accuracy for calculating the estimated casting distance Xd. 
     Instead of using both of the mass parameter C 2  and the weather parameter C 3  as the air resistance parameter, only one may be used. 
     A separate acceleration sensor may be arranged in the weight  20  to detect the actual speed of the fishing line  16 . In this case, the microcomputer  46  can recognize the line speed that is more accurate than the estimated line speed V L . This would, however, require a power supply and the implementation of a wireless communication function and thereby increase the volume and mass of the weight  20 . 
     The present examples and embodiments are to be considered as illustrative and not restrictive, and the invention is not to be limited to the details given herein, but may be modified within the scope and equivalence of the appended claims.