Abstract:
A clutch having high engaging force and featuring of smooth operation, wherein clutch weights that are biased by return elements are subject to thrusting force caused by constraint sections of a main driving plate that receive and convert torque from an engine into the pressing action against engaging slots defined in the clutch weights so as to gain enhanced engaging force even when the minor difference or error existing on the response time of the clutch weight or the strength of the return elements and also provides anti-reversal function to reduced the oscillation and let the power output more smooth and more stable. Accordingly, slippage of clutch and wear of the clutch wear pad are both reduced and temperature rise of the wear pad is also reduced.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    (a) Technical Field of the Invention 
         [0002]    The present invention relates to a clutch that enhances engaging power, and in particular to a clutch of high engaging power and featuring stable engagement, which increases the engaging power of each clutch shoe to smoothen and stabilize power transmission. 
         [0003]    (b) Description of the Prior Art 
         [0004]    A centrifugal clutch is widely used in an automatic transmission mechanism of a motorcycle. The centrifugal clutch functions to reflect the rotational speed of a driven pulley to cause clutch weights that are in pivotal connection with a base to expand the clutch weights, in response to the increasing of rotational speed, for causing the wear pads to engage a rim of a driven disk and thus transmitting power to a driven shaft for driving wheels of motorcycles forward. When the rotational speed is reduced, the clutch weights are moved inward and closed to each other, and the transmission of power to the driven shaft is cut off. To allow the clutch weights to reflect the variation of rotational speed and to induce effective engagement, each clutch weight is provided with tension spring (return element) on opposite sides of the pivotal point and connecting between adjacent clutch weights. Timing of expansion/closing of the clutch weights is determined by the tension of the spring. 
         [0005]    Theoretically, every two adjacent clutch weights are constrained by the inter-connecting spring. The response characteristics of each clutch weight in action and angle of expansion/closing operation due to outward movement caused by rotation can be made the identical if the tension of all the springs are the same. However, in practice, the base is often in a non-constant speed rotation due to the fact that the rotational speed of the driven pulley is subject to variation by different operations of the acceleration pedal in response to different driving conditions. This makes the centrifugal force of each clutch weight exhibiting difference in response timing. Thus, during the outward expansion and inward closing process, the clutch weight is subject to unstable expansion, leading to oscillatory phenomena of engaging, which causes the transmission of power unstable. 
       SUMMARY OF THE INVENTION 
       [0006]    The primary purpose of the present invention is to provide a clutch that has a high engaging force and realizes stable engagement. 
         [0007]    In view of this, the present invention provides a clutch comprising a base plate assembly comprising a plurality of clutch weights and return elements provided to the clutch weights, wherein the base plate assembly comprises at least one main driving plate and an associated driven plate, the main driving plate forming a plurality of constraint sections corresponding to the clutch weights respectively, the main driving plate being allowed to drive the associated driven plate to corotate in an angularly-offsetting manner, the associated driven plate carrying the clutch weights, each clutch weight installed with an engaging slot for being engaged by the respective constraint section. 
         [0008]    As such, with the practice of the above discussed techniques, the base plate assembly in accordance with the present invention, when put in a gradually increasing speed condition, enhances the engaging force of each clutch weight against a rim of a driven disk by means of a pressing effect induced by the variation of displacement that the respective constraint section takes to engage an inner abutting face of the engaging slot of the clutch weight when the constraint section receives torque from an engine and the solid engaging process ensures an anti-reversal function, which facilitates smoothness and stability of power transmission so as to increase added value of a clutch product and to enhance market competitively and economic value. 
         [0009]    The foregoing object and summary provide only a brief introduction to the present invention. To fully appreciate these and other objects of the present invention as well as the invention itself, all of which will become apparent to those skilled in the art, the following detailed description of the invention and the claims should be read in conjunction with the accompanying drawings. Throughout the specification and drawings identical reference numerals refer to identical or similar parts. 
         [0010]    Many other advantages and features of the present invention will become manifest to those versed in the art upon making reference to the detailed description and the accompanying sheets of drawings in which a preferred structural embodiment incorporating the principles of the present invention is shown by way of illustrative example. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]      FIG. 1  is a perspective view of a clutch constructed in accordance with a first embodiment of the present invention; 
           [0012]      FIG. 2  is another perspective view of the clutch in accordance with the first embodiment of the present invention; 
           [0013]      FIG. 3  is an exploded view of the clutch in accordance with the first embodiment of the present invention; 
           [0014]      FIG. 4  is another exploded view of the clutch in accordance with the first embodiment of the present invention; 
           [0015]      FIG. 5  is a cross-sectional view of the clutch in accordance with the first embodiment of the present invention in an assembled condition; 
           [0016]      FIG. 6  is a plan view of the clutch in accordance with the first embodiment of the present invention in a condition before operation; [clutch weight in closing status] 
           [0017]      FIG. 7  is a plan view of the clutch in accordance with the first embodiment of the present invention illustrating the clutch in operation; [clutch weight slippery engaging with the driven disk] 
           [0018]      FIG. 8  is another plan view of the clutch in accordance with the first embodiment of the present invention illustrating the clutch in operation; [the constraint sections are actuated to press against the engaging slots of clutch wights] 
           [0019]      FIG. 9  is a perspective view of a clutch constructed in accordance with a second embodiment of the present invention; 
           [0020]      FIG. 10  is another perspective view of the clutch in accordance with the second embodiment of the present invention; 
           [0021]      FIG. 11  is an exploded view of the clutch in accordance with the second embodiment of the present invention; 
           [0022]      FIG. 12  is another exploded view of the clutch in accordance with the second embodiment of the present invention; 
           [0023]      FIG. 13  is a cross-sectional view of the clutch in accordance with the second embodiment of the present invention in an assembled condition; 
           [0024]      FIG. 14  is a plan view of the clutch in accordance with the second embodiment of the present invention in a condition before operation [cluth weight in closing status]; 
           [0025]      FIG. 15  is a plan view of the clutch in accordance with the second embodiment of the present invention illustrating the clutch in operation; 
           [0026]      FIG. 16  is a perspective view of a clutch constructed in accordance with a third embodiment of the present invention; 
           [0027]      FIG. 17  is an exploded view of the cutch in accordance with the third embodiment of the present invention; 
           [0028]      FIG. 18  is a plan view of the clutch in accordance with the third embodiment of the present invention in a condition before operation [clutch weight in closing status]; 
           [0029]      FIG. 19  is a plan view of the clutch in accordance with the third embodiment of the present invention illustrating the clutch in operation [clutch weights in slippery engaging with driven disk but the constraint sections are not actuated]; 
           [0030]      FIG. 20  is another plan view of the clutch in accordance with the third embodiment of the present invention illustrating the clutch in operation [the constraint sections are actuated to press against the engaging slots of clutch weights]; 
           [0031]      FIG. 21  is a table showing the result of static engaging torque of the present invention; and 
           [0032]      FIG. 22  is a table showing the road text or field test of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0033]    The following descriptions are of exemplary embodiments only, and are not intended to limit the scope, applicability or configuration of the invention in any way. Rather, the following description provides a convenient illustration for implementing exemplary embodiments of the invention. Various changes to the described embodiments may be made in the function and arrangement of the elements described without departing from the scope of the invention as set forth in the appended claims. 
         [0034]    A clutch that has a high engaging force and smooth engagement is illustrated in  FIGS. 1-6 . The clutch comprises a base plate assembly  10  that rotatably carries a plurality of clutch weights  20  and a tension spring based return element  30  is connected between adjacent clutch weights  20 , see  FIG. 6 . The base plate assembly  10  comprises a main driving plate  11  and an associated driven plate  12 , wherein the main driving plate  11  is provided with a plurality of constraint sections  13  corresponding to the clutch weights  20  respectively and extending through the associated driven plate  12  and the main driving plate  11  is allowed to drive the associated driven plate  12  in an angularly offsetting manner. The associated driven plate  12  is provided with pivot pins  14  pivoting the clutch weights  20  respectively. Each clutch weight  20  has an inside surface, which forms, at a location corresponding to the respective constraint section  13 , an engaging slot  21  that has an inner abutting face  210  for engaging the constraint section  13 , as shown in  FIGS. 5 and 6 . 
         [0035]    As shown in  FIGS. 5-8 , when the installed clutch is rotated and the speed is gradually increased to a certain speed, then the constraint section  13  of each clutch weight  20  will proceed displacement to press into the inner abutting face  210  of respective clutch weight  20 , this pressing action enhances the engaging force of each clutch weight and makes the engagement is anti-reversal, thereby the transmission of power is more smooth and more stable. 
         [0036]    In the practice of the present invention, as shown in  FIGS. 3-6 , the main driving plate  11  of the base plate assembly  10  is provided, at locations corresponding to the inside surfaces of the clutch weights  20 , with the plurality of pin-like constraint sections  13 , respectively, which extend through elongated curved slots  120  defined in the associated driven plate  12 . The plate surface of the main driving plate  11  forms a plurality of intermediate corotating element mounting slots  110 . The associated driven plate  12  is formed a plurality of receiving slots  121  corresponding to the mounting slots  110 . An intermediate corotating element  40 , which is compressible and resilient, is arranged in the paired mounting slot  110  and receiving slot  121 . Thus, as shown in  FIGS. 5-8 , when the base plate assembly  10  is in a condition of gradually increasing rotational speed, an increased centrifugal force is induced to drive each clutch weight  20  outward for engagement, and when the associated driven plate  12  is subject to a resistance force, which is greater than predetermined deformation strength of the intermediate corotating element  40 , the intermediate corotating element  40  will be deformed to effect angularly offsetting driving coupling between the main driving plate  11  and the associated driven plate  12 , thereby allowing the pin-like constraint sections  13  of the main driving plate  11  to receive the torque transmitted from an engine and abut against the inclined abutting face  210  of the V-shaped engaging slot  21  of the clutch weight  20  to induce a pressing effect that enhances the engaging force of the clutch weight  20  applies to a rim  51  of a driven disk  50  and also effecting anti-reversal function to reduce oscillation frequency during the engaging process that the clutch weight  20  displaces outward to engage the rim  51  of the driven disk  50  so as to enhance smoothness and stability of power transmission. Such enhancement of engaging force and anti-reversal function shortens the period of slippage during which the wear pad  22  of the clutch weight  20  is in slippage with the rim of the driven disk  50  so that the abrasion/wear of the wear pad is reduced and the rise of temperature of the wear pad is also reduced, which together lead to an increase of life span of the wear pad. 
         [0037]    The above described first embodiment of the present invention can be practiced with excellent result with the following structure, wherein the main driving plate  11  of the base plate assembly  10  is formed with a constraint flange  111  along each mounting slot  110 . The constraint flange  111  functions to constrain the intermediate corotating element  40  from separation. The intermediate corotating element  40  is a rubber or plastic bar that is resistant to chemicals and is of high flexibility and compressibility, so that as shown in  FIGS. 5-8 , when the main driving plate  11  rotates, the intermediate corotating element  40  serves as a medium will be deformed to effect a small angle shifting between the associated driven plate  12  and the main driving plate  11  to thereby enhance the engaging force that the clutch weight  20  applies to the driven disk  50 ; and when the rotational speed of the base plate assembly  10  is apparently slowed down, the intermediate corotating element  40  efficiently releases the compression thereof to generate a recoiling force to immediately return the constraint section  13  back to home position, which releases the pressing effect of the constraint section  13  applies to the clutch weight  20  to allow the clutch weight  20  to easily swing back and close. 
         [0038]    Based on the previously discussed first embodiment, the intermediate corotating element  40  that is arranged in the mounting slot  110  of the main driving plate  11  and the receiving slot  121  of the associated driven plate  12  can be substituted by a compression spring, which can serve for the same function and purposes of the rubber/plastic bar mentioned above. 
         [0039]    Further, based on the practice of the present invention as discussed above, the present invention can achieve the same effect and function with the following second embodiment thereof, which is shown in  FIGS. 9-14 . The main driving plate  11  of the base plate assembly  10  is provided, on an inside plate surface thereof in an axial direction, with an operation-assisting frame  15  that extends through the associated driven plate  12 . The operation-assisting frame  15  is formed, on an inner edge thereof, with a plurality of radially projecting constraint sections  13 A at locations corresponding to the clutch weights  20  respectively, and a plurality of hook sections  150 . Each hook section  150  is formed with a connecting hole  151 . The associated driven plate  12  is formed with a plurality of retention holes  122  corresponding to the connecting holes  151 . The paired connecting hole  151  and the retention hole  122 , which are respectively formed on the operation-assisting frame  15  of the main driving plate  11  and the associated driven plate  12 , are engaged with opposite ends of coil spring based intermediate corotating element  41  that is capable only of limited offsetting shifting. The associated driven plate  12  is pivotally installed with clutch weights  20  through pivot pins  14  with the constraint sections  13 A located in and in abutting engagement with the V-shaped engaging slot  21 . Thus, when the base plate assembly  10  is accelerated to increase the speed to certain rev high enough, the clutch weights  20  fly centrifugally outward to proceed the engagement and the associated driven plate  12  is subject to a rotation resistance that exceeding a predetermined deformation torque of the coil spring based intermediate corotating element  41 , the coil spring based intermediate corotating element  41  will be deformed and an angularly offsetting driving coupling is effected between the main driving plate  11  and the associated driven plate  12 , that is the main driving plate will drive the associated driven plate to corotate in an angularly offsetting driving whereby the main driving plate  11  will transfers the torque received from the engine to the constraint sections  13 A and thus makes each constraint section  13 A abutting against the inclined abutting face  210  of the V-shaped engaging slot  21  of the clutch weigh  20  to enhance the engaging force that each clutch wear pad  22  of the clutch weight  20  applies to the rim  51  of a driven disk  50  and also effect an irreversible engagement of the clutch weight  20  with the rim  51  by means of the pressing effect that constraint section  13 A applies to the V-shaped engaging slot  21  of the clutch weight  20  to thereby provide the anti-reversal function to reduce the oscillation frequency, leading to enhancement of smoothness and stability of power transmission and to reduce abrasion and wear of the wear pad  22  of the clutch weight  20 . Further, in such a structure, as shown in  FIGS. 10-15 , the main driving plate  11  is formed a circular bore  130  in the radially projecting constraint sections  13 A of the operation-assisting frame  15  and a roller  131  is rotatably mounted in the bore  130  with a rolling surface of the roller  131  engaging with the V-shaped engaging slot  21  of the clutch weight  20  for effecting displacement by rolling so that the inclined abutting face  210  of the V-shaped engaging slot  21  is protected from wear and abrasion. 
         [0040]    Further, the structure of the second embodiment has been tested for static engaging torque of which the result is shown in  FIG. 21  and road test or field test of which the result is shown in  FIG. 22 . The test results indicate the improvement of the present invention in the performance of clutch. In the engaging torque test shown in  FIG. 21 , the pressing force, that is induced by the centrifugal force of the clutch weights, against the rim  51  of the driven disk  50  [clutch bell], is simulatively performed with pneumatic force of an air compressor to generate a pressing force substantially identical to the centrifugal force of the clutch weights. After several runs of test, as indicated in the table of  FIG. 21 , under different settings of pneumatic force, the engaging torque that the clutch of the present invention applies to the clutch bell is increased more than 30%. 
         [0041]    The on road test or field test of  FIG. 22  is carried out with motorcycle of model Kymco Grand Dink 250, with two persons riding on the motorcycle and the text is performed on roads of different slopes. The vehicle is put in a standstill condition and the engine is accelerated to one engine revolution speed for vehicle just starting to move. The result is put in comparison with a conventional clutch in the table of  FIG. 22 , and as indicated in the table, the clutch in accordance with the second embodiment of the present invention for containing with intermediate corotating element (Structure A) and containing without intermediate corotating element (Structure B) realize the effect of enhancing engaging force of clutch weights and provide a sufficient engaging torque to the clutch bell whereby the clutch weights of the clutch in accordance with the present invention are capable to drive the clutch bell to rotate with reduced period of time in which the clutch weights are in slippage condition inside the clutch bell. Thus, the rise of temperature at the interface of the clutch weight of the clutch in accordance with the present invention can be reduced and clutch wear pad of the clutch weight is not readily burn and generate odors and the service life is extended. The test also indicates that the presence of the intermediate corotating element and the deformation setting thereof determine the actuation timing of offsetting driving coupling. 
         [0042]    The test also indicates that the conventional clutch, due to the small engaging force provided by the clutch weight, cannot drive the clutch bell to rotate until the engine reaches high revolution whereby the clutch wear pad of the clutch is put in slippage with the clutch bell for a very long period of time so that the interface of the clutch wear pad is subject to a significant rise of temperature and is thus burnt, leading to accelerated wear thereof. 
         [0043]    Further, based on the practice of the present invention as discussed above, the present invention can achieve the same effect and function with the following third embodiment thereof, which is shown in  FIGS. 16-18 . The main driving plate  11  of the base plate assembly  10  is provided with an extended operation-assisting frame  15 A and a plurality of intermediate corotating element  40 A is arranged between the operation assisting frame  15 A and the associated driven plate  12 . Thus, the main driving plate  11  that is in rotation can drive the associated driven plate  12  to corotate by means of the operation-assisting frame  15 A and the intermediate corotating element  40 A. The operation-assisting frame  15 A forms a plurality of projecting constraint sections  13 A at locations corresponding to clutch weights  20 A respectively. The associated driven plate  12  is installed with the clutch weights  20 A and each clutch weight formed an engaging slot  21  for being engaged by the projecting constraint section  13 A. As shown in  FIGS. 18-20 , when the base plate assembly  10  that is of variable rotational speed continuously rotates to a predetermined speed, the clutch weights  20 A fly outward by centrifugal forces to carry out engagement when the rotation resistance, subjected by the associated driven plate  12 , is higher than the predetermined deformation setting of the intermediate corotating element  40 A, an angularly offsetting driving coupling is effected between the main driving plate  11  and the associated driven plate  12 , whereby the constraint sections  13 A of the main driving plate  11  will receive the torque transmitted from the engine and applies a pressing force against the engaging slots  21  of the clutch weights  20  respectively, so that the engaging force of each clutch weight  20 A is enhanced with the pressing effect realized by the displacement that each constraint section  13 A takes to abut into an inner abutting face  210  of the engaging slot  21  of the respective clutch weight  20 . 
         [0044]    The present invention can be practiced in a more detailed construction in accordance with the third embodiment discussed above as shown in  FIGS. 16-18 , wherein the operation-assisting frame  15 A of the main driving plate  11  of the base plate assembly  10  is formed with a plurality of first hooking sections  152 . The associated driven plate  12  is formed with a plurality of retention sections  123  corresponding tot he first hooking sections  152 . The opposite ends of each spring based intermediate corotating element  40 A are respectively mounted to the respective retention section  123  and the associated first hooking section  152 . As shown in  FIGS. 18 ,  19 , and  20 , when the base plate assembly  10  is gradually increased with the rotational speed thereof to induce the engagement operation of the clutch weights  20  by means of action of centrifugal force, with the associated driven plate  12  being subjected to a rotational resistance that exceeding the predetermined setting of deformation strength of the spring based intermediate corotating element  40 A, an angularly offsetting driving coupling is established between the main driving plate  11  and the associated driven plate  12  to let the projecting constraint sections  13 A of the main driving plate  11  convert the torque received from the engine into pressing against the inclined abutting face  210  of the V-shaped engaging slot  21  of the clutch weight thereby inducing a pressing effect. 
         [0045]    A more detailed structure of the third embodiment of the present invention will be further described, as shown in  FIGS. 16-18 , wherein the operation-assisting frame  15 A of the main driving plate  11  of the base plate assembly  10  is provided with a plurality of second hooking sections  153 . The associated driven plate  12  is formed with a plurality of guide frame  124  for mounting the clutch weights  20 A. Each clutch weight  20 A has a return element  30  that connects the respective second hooking section  153  of the operation-assisting frame  15 . Each clutch weight  20 A is formed with, at an inside surface thereof, an engaging slot  21  at each location corresponding to the projecting constraint sections  13 A so that the projecting constraint sections  13 A can be put in abutting engagement with the engaging slots  21  respectively. As such, the engaging force of each clutch weight  20 A applies to the rim  51  of the driven disk  50  can be enhanced, while due to the pressing effect provided by the projecting constraint section  13 A, the action of displacement and engagement taken by the clutch weight  20 A under the guidance of the guide frame  124  is irreversible thereby ensure smoothness and stability of power transmission. 
         [0046]    According to the first, second, and third embodiments described above, the present invention can be made more enhanced with the following structure, wherein, as shown in  FIGS. 10-14 , each clutch weight  20  is formed with a fixing port  23  corresponding to each constraint section  13 A and a wear-resistant pillow block  24  is fixed inside the fixing port  23 . The wear-resistant pillow block  24  is formed with an engaging slot  21  and each engaging slot  21  is engaged by each respective constraint section  13 A. And the engaging slot  21  can be made to be wear resistant and hard to deform. This also includes the benefit of getting different weights of clutch weights and various slope of abutting face  210  of engaging slot  21  by only replacing the wear-resistant pillow block  24 . In other words replacing the material or specific gravity of wear-resistant pillow block  24  and the slope of abutting face  210  can achieve the best engaging force in different requirements. 
         [0047]    Although the present invention has been described with reference to the preferred embodiments thereof, it is apparent to those skilled in the art that a variety of modifications and changes may be made without departing from the scope of the present invention which is intended to be defined by the appended claims. 
         [0048]    It will be understood that each of the elements described above, or two or more together may also find a useful application in other types of methods differing from the type described above. 
         [0049]    While certain novel features of this invention have been shown and described and are pointed out in the annexed claim, it is not intended to be limited to the details above, since it will be understood that various omissions, modifications, substitutions and changes in the forms and details of the device illustrated and in its operation can be made by those skilled in the art without departing in any way from the spirit of the present invention.