Patent Publication Number: US-7713162-B2

Title: Multi-speed transmission

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application No. 60/867,683, filed Nov. 29, 2006, and is a divisional application of U.S. patent application Ser. No. 11/771,393, filed Jun. 29, 2007, both of which are hereby incorporated by reference in their entireties. 
    
    
     TECHNICAL FIELD 
     This invention relates to a multi-speed transmission for a vehicle providing a plurality of forward speed ratios and at least one reverse speed ratio through selective engagement of six torque-transmitting mechanisms located in a selected zone or zones of the transmission. 
     BACKGROUND OF THE INVENTION 
     Multi-speed transmissions in automotive vehicles allow for operating efficiency and smooth feel. Multiple planetary gear sets have been utilized to provide eight or more forward speed ratios with relatively efficient packaging due to the compact nature of planetary gear sets. A number of selectively engagable torque-transmitting mechanisms are controlled to interconnect different members of the planetary gear sets with one another, with the transmission casing, or sometimes with the transmission input or output member to achieve the various speed ratios. Efficient packaging of the torque-transmitting mechanisms helps to minimize the overall dimensions of the transmission, potentially allowing its use in more vehicle platforms, reducing weight, and minimizing manufacturing complexity. 
     SUMMARY OF THE INVENTION 
     A multi-speed transmission is provided with three planetary gear sets, each having a ring gear member, a sun gear member and a carrier member that rotatably supports a plurality of pinion gears that intermesh with both the sun gear member and the ring gear member. Certain members of the gear sets are continuously connected for common rotation. Specifically, an interconnecting member continuously interconnects for common rotation the carrier member of the first planetary gear set, the sun gear member of the second planetary gear set and the ring gear member of the third planetary gear set. Additionally, the sun gear member of the first planetary gear set is continuously grounded to the transmission casing. 
     Preferably, an input member is continuously interconnected for common rotation with the sun gear member of the third planetary gear set, and an output member is continuously interconnected for common rotation with the ring gear member of the second planetary gear set. 
     Six torque-transmitting mechanisms are selectively engagable to connect selected members of the planetary gear sets for common rotation. The six torque-transmitting mechanisms are engagable in different combinations to achieve eight forward speed ratios and a reverse speed ratio between the input member and the output member. 
     A transmission casing surrounds the planetary gear sets and torque-transmitting mechanisms and defines a cavity having five different zones. The transmission casing includes opposing first and second end walls and a housing portion therebetween. As used herein, a “zone” is a portion of the cavity. A first zone extends axially from the first end wall to one of the planetary gear sets. A second and a third zone each extends between different adjacent pairs of the planetary gear sets. A fourth zone extends from another one of the planetary gear sets to the second end wall. Each of the first, second, third, and fourth zones extends radially to an outer surface of a radially-outermost one of the members. A fifth zone borders the first, second, third, and fourth zones, extends radially outward to the housing portion and extends axially between the first and second end walls. 
     Each torque-transmitting mechanism may be located in selected ones of the zones that further desirability of (i) minimizing the overall size of the transmission, (ii) reducing weight, (iii) providing a convenient location for hydraulic feed to the torque-transmitting mechanism, such as by locating the torque-transmitting mechanism close to the transmission casing or to a centrally-located shaft, both of which typically define at least part of a feed path to supply hydraulic fluid to torque-transmitting mechanisms, and (iv) reducing the overall complexity (e.g., the number, shape and size of hub members and other interconnecting members used to connect members of the planetary gear sets with one another or with the transmission casing). Different embodiments of the transmission are possible by arranging the planetary gear sets in a different order (e.g., the order moving axially from the first end wall to the second end wall) in the transmission. The six torque-transmitting mechanisms are located in at least one of the five zones in each such embodiment within the scope of the invention. 
     Preferably, the sun gear member of the first planetary gear set is continuously grounded to the transmission casing via a radially-extending structural member. At least one of the torque-transmitting mechanisms selectively grounds one of the members of one of the planetary gear sets to the transmission casing via the radially-extending structural member. 
     The above features and advantages and other features and advantages of the present invention are readily apparent from the following detailed description of the best modes for carrying out the invention when taken in connection with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  is a schematic, cross-sectional, partially fragmentary illustration of a first embodiment of a multi-speed transmission within the scope of the invention; 
         FIG. 1B  is a chart listing the selected zones of the transmission casing of the transmission of  FIG. 1A  in which various torque-transmitting mechanisms may be located; 
         FIG. 2A  is a schematic, cross-sectional, partially fragmentary illustration of a second embodiment of a multi-speed transmission within the scope of the invention; 
         FIG. 2B  is a chart listing the selected zones of the transmission casing of the transmission of  FIG. 2A  in which various torque-transmitting mechanisms may be located; 
         FIG. 3A  is a schematic, cross-sectional, partially fragmentary illustration of a third embodiment of a multi-speed transmission within the scope of the invention; 
         FIG. 3B  is a chart listing the selected zones of the transmission casing of the transmission of  FIG. 3A  in which various torque-transmitting mechanisms may be located; 
         FIG. 4A  is a schematic, cross-sectional, partially fragmentary illustration of a fourth embodiment of a multi-speed transmission within the scope of the invention; 
         FIG. 4B  is a chart listing the selected zones of the transmission casing of the transmission of  FIG. 4A  in which various torque-transmitting mechanisms may be located; 
         FIG. 5A  is a schematic, cross-sectional, partially fragmentary illustration of a fifth embodiment of a multi-speed transmission within the scope of the invention; 
         FIG. 5B  is a chart listing the selected zones of the transmission casing of the transmission of  FIG. 5A  in which various torque-transmitting mechanisms may be located; 
         FIG. 6A  is a schematic, cross-sectional, partially fragmentary illustration of a sixth embodiment of a multi-speed transmission within the scope of the invention; 
         FIG. 6B  is a chart listing the selected zones of the transmission casing of the transmission of  FIG. 6A  in which various torque-transmitting mechanisms may be located; 
         FIG. 7A  is a schematic, cross-sectional, partially fragmentary illustration of a seventh embodiment of a multi-speed transmission within the scope of the invention; 
         FIG. 7B  is a chart listing the selected zones of the transmission casing of the transmission of  FIG. 7A  in which various torque-transmitting mechanisms may be located; 
         FIG. 8A  is a schematic, cross-sectional, partially fragmentary illustration of an eighth embodiment of a multi-speed transmission within the scope of the invention; 
         FIG. 8B  is a chart listing the selected zones of the transmission casing of the transmission of  FIG. 8A  in which various torque-transmitting mechanisms may be located; 
         FIG. 9A  is a schematic, cross-sectional, partially fragmentary illustration of a ninth embodiment of a multi-speed transmission within the scope of the invention; and 
         FIG. 9B  is a chart listing the selected zones of the transmission casing of the transmission of  FIG. 9A  in which various torque-transmitting mechanisms may be located. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to the drawings, wherein like reference numbers refer to like components,  FIG. 1A  shows a transmission  10  having an input member  12  for receiving power from a power source such as an internal combustion engine and output member  14  for delivering power to a final drive mechanism such as the wheels of a vehicle. 
     The transmission  10  includes a gearing arrangement  16  having three planetary gear sets  20 ,  30  and  40  and six selectively engagable torque-transmitting mechanisms  50 ,  52 ,  54 ,  56 ,  57  and  58 . Each planetary gear set  20 ,  30  and  40  includes rotatable components concentric with a centerline  60  of the transmission  10 . Specifically, planetary gear set  20  includes a sun gear member  22 , a ring gear member  24  and a carrier member  26  that rotatably supports a plurality of pinion gears  27  that intermesh with both the sun gear member  22  and the ring gear member  24 . Planetary gear set  30  includes a sun gear member  32 , a ring gear member  34  and a carrier member  36  that rotatably supports a plurality of pinion gears  37  that intermesh with both the sun gear member  32  and the ring gear member  34 . Planetary gear set  40  includes a sun gear member  42 , a ring gear member  44  and a carrier member  46  that rotatably supports a plurality of pinion gears  47  that intermesh with both the sun gear member  42  and the ring gear member  44 . 
     In referring to the first, second and third gear planetary gear sets in this description and in the claims, these sets may be counted “first” to “third” in any order in the drawings (i.e., left to right, right to left, etc.). In the embodiment of  FIG. 1A , planetary gear set  30  is the first planetary gear set, planetary gear set  40  is the second planetary gear set, and planetary gear set  20  is the third planetary gear set. 
     The input member  12  is continuously connected for common rotation with sun gear member  22 . The output member  14  is continuously connected for common rotation with ring gear member  44 . An interconnecting member  70  continuously interconnects ring gear member  24  with carrier member  36  and sun gear member  42 . The interconnecting member  70  may be one component or multiple components. The sun gear member  32  is continuously grounded to a housing  80  (also referred to herein as a housing portion) of the transmission  10  via a radially-extending structural member  81 . The housing  80  circumferentially surrounds the gear sets  20 ,  30  and  40  as well as the torque-transmitting mechanisms  50 ,  52 ,  54 ,  56 ,  57  and  58 . The transmission  10  further includes a first end wall  82  generally at one end of the transmission  10  and a second end wall  84  generally at an opposing end of the transmission  10 . The housing  80  joins the first and second end walls  82 ,  84 . It should be appreciated that the housing  80  and the first and second end walls  82 ,  84  form a transmission casing, and may be integrated, or may each be a separate component or components of the casing. The transmission casing may be referred to herein as  80 ,  82 ,  84 . The transmission casing  80 ,  82 ,  84  defines a cavity  85 . The end walls  82  and  84  enclose the cavity  85  axially, but are likely a conical or irregular shape rather than a planar shape as schematically depicted. 
     The planetary gear sets  20 ,  30 , and  40  and torque-transmitting mechanisms  50 ,  52 ,  54 ,  56 ,  57 , and  58  are located in the cavity  85 . The housing  80 , end walls  82  and  84  and the planetary gear sets  20 ,  30  and  40  cooperate to define five spaces or zones within the cavity  85 . A first zone I is defined between an outer surface  86  of the first end wall  82  and a plane  88  running generally parallel with a side of the planetary gear set  20  adjacent the first end wall  82 , and runs radially outward to a circumferential boundary  90  running along a radially-outermost periphery of each of the ring gear members  24 ,  34  and  44 . A second zone II is defined between a plane  92  running generally parallel along a side of the planetary gear set  20  facing the planetary gear set  30 , a plane  94  running generally parallel along a side of the planetary gear set  30  facing the planetary gear set  20  and the circumferential boundary  90 . A third zone III is defined between a plane  95  running generally parallel along a side of the planetary gear set  30  facing the planetary gear set  40 , a plane  96  running generally parallel along a side of the planetary gear set  40  facing the planetary gear set  30  and the circumferential boundary  90 . A fourth zone IV is defined between a plane  97  running generally parallel along a side of the planetary gear set  40  facing the second end wall  84 , an outer surface  98  of the second end wall  84  and the circumferential boundary  90 . A fifth zone V is defined between the circumferential boundary  90 , an outer surface  99  of the housing  80 , and the outer surfaces  86  and  98  of the first and second end walls  82  and  84 , respectively. The structural member  81  traverses zones III and V. 
     Torque-transmitting mechanisms  50 ,  52 ,  54 , and  56  are rotating-type clutches and torque-transmitting mechanisms  57  and  58  are brakes, also referred to as reaction clutches or stationary clutches. Torque-transmitting mechanism  50  is selectively engagable to connect the carrier member  26  for common rotation with the ring gear member  34 . The torque-transmitting mechanism  52  is selectively engagable to connect the input member  12  and the sun gear member  22  for common rotation with the ring gear member  34 . The torque-transmitting mechanism  54  is selectively engagable to connect the carrier member  26  for common rotation with the carrier member  46 . The torque-transmitting mechanism  56  is selectively engagable to connect the input member  12  and the sun gear member  22  for common rotation with the carrier member  46 . The torque-transmitting mechanism  57  is selectively engagable to ground the carrier member  36  (as well as the ring gear member  24  and sun gear member  42 ) to the transmission housing  80  via the structural member  81 . The torque-transmitting mechanism  58  is selectively engagable to ground the carrier member  46  to the transmission housing  80  via the structural member  81 . 
     The transmission  10  provides eight forward speed ratios and one reverse speed ratio between the input member  12  and the output member  14 . Specifically, a reverse speed ratio is established by engaging torque-transmitting mechanisms  52  and  58 ; a first forward speed ratio is established by engaging torque-transmitting mechanisms  54  and  58 ; a second forward speed ratio is established by engaging torque-transmitting mechanisms  54  and  57 ; a third forward speed ratio is established by engaging torque-transmitting mechanisms  50  and  54 ; a fourth forward speed ratio is established by engaging torque-transmitting mechanisms  52  and  54 ; a fifth forward speed ratio is established by engaging torque-transmitting mechanisms  54  and  56 ; a sixth forward speed ratio is established by engaging torque-transmitting mechanisms  52  and  56 ; a seventh forward speed ratio is established by engaging torque-transmitting mechanisms  50  and  56 ; and an eighth forward speed ratio is established by engaging torque-transmitting mechanisms  56  and  57 . Preferably, in all embodiments of the invention, at least three of the speed ratios are overdrive ratios. 
     As shown in  FIG. 1A , torque-transmitting mechanisms  54  and  56  are located in zone II; torque-transmitting mechanisms  57  and  58  are disposed in zone III; and torque-transmitting mechanisms  50  and  52  are disposed in zone V. Alternatively, the interconnections between the various gear members, the input member  12 , the output member  14  and the housing  80  obtained by selective engagement of the various torque-transmitting mechanism as described above are possible with the torque-transmitting mechanisms  50 ,  52 ,  54 ,  56 ,  57  and  58  disposed in other zones as shown in the chart of  FIG. 1B . An “X” in the chart of  FIG. 1B  shown below indicates that the particular torque-transmitting mechanism is positionable in the referenced zone and an “O” indicates that the particular torque-transmitting mechanisms are not to be located in the referenced zone. It should be appreciated that the selection of location for the torque-transmitting mechanism of each row in the chart of  FIG. 1B  is feasible independently of the other rows. Accordingly, torque-transmitting mechanism  50  is locatable in any of four possible zones; torque-transmitting mechanism  52  is locatable in any of four possible zones; torque-transmitting mechanism  54  is locatable in any of three possible zones; torque transmitting mechanism  56  is locatable in any of three possible zones; torque-transmitting mechanism  57  is locatable in any of two possible zones; and torque-transmitting mechanism  58  is locatable in any of three possible zones. 
     A second embodiment of a transmission  100  within the scope of the invention is shown in  FIG. 2A . Transmission  100  has an input member  112  for receiving power from a power source such as an internal combustion engine and output member  114  for delivering power to a final drive mechanism such as the wheels of a vehicle. Both the input member  112  and the output member  114  extend through a first end wall  182  of the transmission  100 . 
     The transmission  100  includes a gearing arrangement  116  having three planetary gear sets  120 ,  130  and  140  and six selectively engagable torque-transmitting mechanisms  150 ,  152 ,  154 ,  156 ,  157  and  158 . In the embodiment of  FIG. 2A , planetary gear set  140  is the first planetary gear set, planetary gear set  120  is the second planetary gear set, and planetary gear set  130  is the third planetary gear set. 
     Each planetary gear set  120 ,  130  and  140  includes rotatable components concentric with a centerline  160  of the transmission  100 . Specifically, planetary gear set  120  includes a sun gear member  122 , a ring gear member  124  and a carrier member  126  that rotatably supports a plurality of pinion gears  127  that intermesh with both the sun gear member  122  and the ring gear member  124 . Planetary gear set  130  includes a sun gear member  132 , a ring gear member  134  and a carrier member  136  that rotatably supports a plurality of pinion gears  137  that intermesh with both the sun gear member  132  and the ring gear member  134 . Planetary gear set  140  includes a sun gear member  142 , a ring gear member  144  and a carrier member  146  that rotatably supports a plurality of pinion gears  147  that intermesh with both the sun gear member  142  and the ring gear member  144 . 
     The input member  112  is continuously connected for common rotation with sun gear member  132 . The output member  114  is continuously connected for common rotation with ring gear member  124 . An interconnecting member  170  continuously interconnects ring gear member  134  with carrier member  146  and sun gear member  122 . The interconnecting member  170  may be one component or multiple components. The sun gear member  142  is continuously grounded to a housing  180  of the transmission  100  via a radially-extending structural member  181 . The housing  180  circumferentially surrounds the gear sets  120 ,  130  and  140  as well as the torque-transmitting mechanisms  150 ,  152 ,  154 ,  156 ,  157  and  158 . The transmission  100  further includes a first end wall  182  generally at one end of the transmission  100  and a second end wall  184  generally at an opposing end of the transmission  100 . The housing  180  joins the first and second end walls  182 ,  184 . It should be appreciated that the housing  180  and the first and second end walls  182 ,  184  form a transmission casing, and may be integrated, or may each be a separate component or components of the casing. The transmission casing may be referred to herein as  180 ,  182 ,  184 . The transmission casing  180 ,  182 ,  184  defines a cavity  185 . The end walls  182  and  184  enclose the cavity  185  axially, but are likely a conical or irregular shape rather than a planar shape as schematically depicted. 
     The planetary gear sets  120 ,  130 , and  140  and torque-transmitting mechanisms  150 ,  152 ,  154 ,  156 ,  157 , and  158  are located in the cavity  185 . The housing  180 , end walls  182  and  184  and the planetary gear sets  120 ,  130  and  140  cooperate to define five spaces or zones within the cavity  185 . A first zone I is defined between an outer surface  186  of the first end wall  182  and a plane  188  running generally parallel with a side of the planetary gear set  120  adjacent the first end wall  182 , and runs radially outward to a circumferential boundary  190  running along a radially-outermost periphery of each of the ring gear members  124 ,  134  and  144 . A second zone II is defined between a plane  192  running generally parallel along a side of the planetary gear set  120  facing the planetary gear set  130 , a plane  194  running generally parallel along a side of the planetary gear set  130  facing the planetary gear set  120  and the circumferential boundary  190 . A third zone III is defined between a plane  195  running generally parallel along a side of the planetary gear set  130  facing the planetary gear set  140 , a plane  196  running generally parallel along a side of the planetary gear set  140  facing the planetary gear set  130  and the circumferential boundary  190 . A fourth zone IV is defined between a plane  197  running generally parallel along a side of the planetary gear set  140  facing the second end wall  184 , an outer surface  198  of the second end wall  184  and the circumferential boundary  190 . A fifth zone V is defined between the circumferential boundary  190 , an outer surface  199  of the housing  180 , and the outer surfaces  186  and  198  of the first and second end walls  182  and  184 , respectively. The structural member  181  traverses zones III and V. 
     Torque-transmitting mechanisms  150 ,  152 ,  154 , and  156  are rotating-type clutches and torque-transmitting mechanisms  157  and  158  are brakes, also referred to as reaction clutches. Torque-transmitting mechanism  150  is selectively engagable to connect the carrier member  136  for common rotation with the ring gear member  144 . The torque-transmitting mechanism  152  is selectively engagable to connect the input member  112  and the sun gear member  132  for common rotation with the ring gear member  144 . The torque-transmitting mechanism  154  is selectively engagable to connect the carrier member  126  for common rotation with the carrier member  136 . The torque-transmitting mechanism  156  is selectively engagable to connect the input member  112  and the sun gear member  132  for common rotation with the carrier member  126 . The torque-transmitting mechanism  157  is selectively engagable to ground the carrier member  146  (as well as the sun gear member  122  and ring gear member  134 ) to the transmission housing  180  via the structural member  181 . The torque-transmitting mechanism  158  is selectively engagable to ground the carrier member  126  to the transmission housing  180  via the structural member  181 . 
     The transmission  100  provides eight forward speed ratios and one reverse speed ratio between the input member  112  and the output member  114 . Specifically, a reverse speed ratio is established by engaging torque-transmitting mechanisms  152  and  158 ; a first forward speed ratio is established by engaging torque-transmitting mechanisms  154  and  158 ; a second forward speed ratio is established by engaging torque-transmitting mechanisms  154  and  157 ; a third forward speed ratio is established by engaging torque-transmitting mechanisms  150  and  154 ; a fourth forward speed ratio is established by engaging torque-transmitting mechanisms  152  and  154 ; a fifth forward speed ratio is established by engaging torque-transmitting mechanisms  154  and  156 ; a sixth forward speed ratio is established by engaging torque-transmitting mechanisms  152  and  156 ; a seventh forward speed ratio is established by engaging torque-transmitting mechanisms  150  and  156 ; and an eighth forward speed ratio is established by engaging torque-transmitting mechanisms  156  and  157 . 
     As shown in  FIG. 2A , torque-transmitting mechanism  156  is located in zone I; torque-transmitting mechanisms  154  and  158  are located in zone II; torque-transmitting mechanisms  150  and  152  are disposed in zone III; and torque-transmitting mechanism  157  is disposed in zone V. Alternatively, the interconnections between the various gear members, the input member  112 , the output member  114  and the housing  180  obtained by selective engagement of the various torque-transmitting mechanism as described above are possible with the torque-transmitting mechanisms  150 ,  152 ,  154 ,  156 ,  157  and  158  disposed in other zones as shown in the chart II of  FIG. 2B . An “X” in the chart of  FIG. 2B  indicates that the particular torque-transmitting mechanism is positionable in the referenced zone and an “O” indicates that the particular torque-transmitting mechanisms are not to be located in the referenced zone. It should be appreciated that the selection of location for the torque-transmitting mechanism of each row in the chart of  FIG. 2B  is feasible independently of the other rows. Accordingly, torque-transmitting mechanism  150  is locatable in any of three possible zones; torque-transmitting mechanism  152  is locatable in any of four possible zones; torque-transmitting mechanism  154  is locatable in any of three possible zones; torque transmitting mechanism  156  is locatable in any of three possible zones; torque-transmitting mechanism  157  is locatable in any of three possible zones; and torque-transmitting mechanism  158  is locatable in any of four possible zones. 
     A third embodiment of a transmission  200  within the scope of the invention is shown in  FIG. 3A . Transmission  200  has an input member  212  for receiving power from a power source such as an internal combustion engine and output member  214  for delivering power to a final drive mechanism such as the wheels of a vehicle. Both the input member  212  and the output member  214  extend through a first end wall  282  of the transmission  200 . 
     The transmission  200  includes a gearing arrangement  216  having three planetary gear sets  220 ,  230  and  240  and six selectively engagable torque-transmitting mechanisms  250 ,  252 ,  254 ,  256 ,  257  and  258 . In the embodiment of  FIG. 3A , planetary gear set  240  is the first planetary gear set, planetary gear set  220  is the second planetary gear set, and planetary gear set  230  is the third planetary gear set. 
     Each planetary gear set  220 ,  230  and  240  includes rotatable components concentric with a centerline  260  of the transmission  200 . Specifically, planetary gear set  220  includes a sun gear member  222 , a ring gear member  224  and a carrier member  226  that rotatably supports a plurality of pinion gears  227  that intermesh with both the sun gear member  222  and the ring gear member  224 . Planetary gear set  230  includes a sun gear member  232 , a ring gear member  234  and a carrier member  236  that rotatably supports a plurality of pinion gears  237  that intermesh with both the sun gear member  232  and the ring gear member  234 . Planetary gear set  240  includes a sun gear member  242 , a ring gear member  244  and a carrier member  246  that rotatably supports a plurality of pinion gears  247  that intermesh with both the sun gear member  242  and the ring gear member  244 . 
     The input member  212  is continuously connected for common rotation with sun gear member  232 . The output member  214  is continuously connected for common rotation with ring gear member  224 . An interconnecting member  270  continuously interconnects ring gear member  234  with carrier member  246  and sun gear member  222 . The interconnecting member  270  may be one component or multiple components. The sun gear member  242  is continuously grounded to a housing  280  of the transmission  200  via a radially-extending structural member  281 . The housing  280  circumferentially surrounds the gear sets  220 ,  230  and  240  as well as the torque-transmitting mechanisms  250 ,  252 ,  254 ,  256 ,  257  and  258 . The transmission  200  further includes a first end wall  282  generally at one end of the transmission  200  and a second end wall  284  generally at an opposing end of the transmission  200 . The housing  280  joins the first and second end walls  282 ,  284 . It should be appreciated that the housing  280  and the first and second end walls  282 ,  284  form a transmission casing, and may be integrated, or may each be a separate component or components of the casing. The transmission casing may be referred to herein as  280 ,  282 ,  284 . The transmission casing  280 ,  282 ,  284  defines a cavity  285 . The end walls  282  and  284  enclose the cavity  285  axially, but are likely a conical or irregular shape rather than a planar shape as schematically depicted. 
     The planetary gear sets  220 ,  230 , and  240  and torque-transmitting mechanisms  250 ,  252 ,  254 ,  256 ,  257 , and  258  are located in the cavity  285 . The housing  280 , end walls  282  and  284  and the planetary gear sets  220 ,  230  and  240  cooperate to define five spaces or zones within the cavity  285 . A first zone I is defined between an outer surface  286  of the first end wall  282  and a plane  288  running generally parallel with a side of the planetary gear set  220  adjacent the first end wall  282 , and runs radially outward to a circumferential boundary  290  running along a radially-outermost periphery of each of the ring gear members  224 ,  234  and  244 . A second zone II is defined between a plane  292  running generally parallel along a side of the planetary gear set  220  facing the planetary gear set  230 , a plane  294  running generally parallel along a side of the planetary gear set  230  facing the planetary gear set  220  and the circumferential boundary  290 . A third zone III is defined between a plane  295  running generally parallel along a side of the planetary gear set  230  facing the planetary gear set  240 , a plane  296  running generally parallel along a side of the planetary gear set  240  facing the planetary gear set  230  and the circumferential boundary  290 . A fourth zone IV is defined between a plane  297  running generally parallel along a side of the planetary gear set  240  facing the second end wall  284 , an outer surface  298  of the second end wall  284  and the circumferential boundary  290 . A fifth zone V is defined between the circumferential boundary  290 , an outer surface  299  of the housing  280 , and the outer surfaces  286  and  298  of the first and second end walls  282  and  284 , respectively. The structural member  281  traverses zones IV and V. 
     Torque-transmitting mechanisms  250 ,  252 ,  254 , and  2156  are rotating-type clutches and torque-transmitting mechanisms  257  and  258  are brakes, also referred to as reaction clutches. Torque-transmitting mechanism  250  is selectively engagable to connect the carrier member  236  for common rotation with the ring gear member  244 . The torque-transmitting mechanism  252  is selectively engagable to connect the input member  212  and the sun gear member  232  for common rotation with the ring gear member  244 . The torque-transmitting mechanism  254  is selectively engagable to connect the carrier member  226  for common rotation with the carrier member  236 . The torque-transmitting mechanism  256  is selectively engagable to connect the input member  212  and the sun gear member  232  for common rotation with the carrier member  226 . The torque-transmitting mechanism  257  is selectively engagable to ground the carrier member  246  (as well as the sun gear member  222  and ring gear member  234 ) to the transmission housing  280  via the structural member  281 . The torque-transmitting mechanism  258  is selectively engagable to ground the carrier member  226  to the transmission housing  280  via the structural member  281 . 
     The transmission  200  provides eight forward speed ratios and one reverse speed ratio between the input member  212  and the output member  214 . Specifically, a reverse speed ratio is established by engaging torque-transmitting mechanisms  252  and  258 ; a first forward speed ratio is established by engaging torque-transmitting mechanisms  254  and  258 ; a second forward speed ratio is established by engaging torque-transmitting mechanisms  254  and  257 ; a third forward speed ratio is established by engaging torque-transmitting mechanisms  250  and  254 ; a fourth forward speed ratio is established by engaging torque-transmitting mechanisms  252  and  254 ; a fifth forward speed ratio is established by engaging torque-transmitting mechanisms  254  and  256 ; a sixth forward speed ratio is established by engaging torque-transmitting mechanisms  252  and  256 ; a seventh forward speed ratio is established by engaging torque-transmitting mechanisms  250  and  256 ; and an eighth forward speed ratio is established by engaging torque-transmitting mechanisms  256  and  257 . 
     As shown in  FIG. 3A , torque-transmitting mechanism  256  is located in zone I; torque-transmitting mechanism  254  is located in zone II; torque-transmitting mechanisms  250  and  252  are disposed in zone III; torque-transmitting mechanism  257  is disposed in zone IV; and torque-transmitting mechanism  258  is disposed in zone V. Alternatively, the interconnections between the various gear members, the input member  212 , the output member  214  and the housing  280  obtained by selective engagement of the various torque-transmitting mechanism as described above are possible with the torque-transmitting mechanisms  250 ,  252 ,  254 ,  256 ,  257  and  258  disposed in other zones as shown in the chart of  FIG. 3B . An “X” in the chart of  FIG. 3B  indicates that the particular torque-transmitting mechanism is positionable in the referenced zone and an “O” indicates that the particular torque-transmitting mechanisms are not to be located in the referenced zone. It should be appreciated that the selection of location for the torque-transmitting mechanism of each row in the chart of  FIG. 3B  is feasible independently of the other rows. Accordingly, torque-transmitting mechanism  250  is locatable in any of three possible zones; torque-transmitting mechanism  252  is locatable if any of two possible zones; torque-transmitting mechanism  254  is locatable in any of three possible zones; torque transmitting mechanism  256  is locatable in any of three possible zones; torque-transmitting mechanism  257  is locatable in any of four possible zones; and torque-transmitting mechanism  258  is locatable in any of four possible zones. 
     A fourth embodiment of a transmission  300  within the scope of the invention is shown in  FIG. 4A . Transmission  300  has an input member  312  for receiving power from a power source such as an internal combustion engine and output member  314  for delivering power to a final drive mechanism such as the wheels of a vehicle. 
     The transmission  300  includes a gearing arrangement  316  having three planetary gear sets  320 ,  330  and  340  and six selectively engagable torque-transmitting mechanisms  350 ,  352 ,  354 ,  356 ,  357  and  358 . In the embodiment of  FIG. 4A , planetary gear set  320  is the first planetary gear set, planetary gear set  340  is the second planetary gear set, and planetary gear set  330  is the third planetary gear set. 
     Each planetary gear set  320 ,  330  and  340  includes rotatable components concentric with a centerline  360  of the transmission  300 . Specifically, planetary gear set  320  includes a sun gear member  322 , a ring gear member  324  and a carrier member  326  that rotatably supports a plurality of pinion gears  327  that intermesh with both the sun gear member  322  and the ring gear member  324 . Planetary gear set  330  includes a sun gear member  332 , a ring gear member  334  and a carrier member  336  that rotatably supports a plurality of pinion gears  337  that intermesh with both the sun gear member  332  and the ring gear member  334 . Planetary gear set  340  includes a sun gear member  342 , a ring gear member  344  and a carrier member  346  that rotatably supports a plurality of pinion gears  347  that intermesh with both the sun gear member  342  and the ring gear member  344 . 
     The input member  312  is continuously connected for common rotation with sun gear member  332 . The output member  314  is continuously connected for common rotation with ring gear member  344 . An interconnecting member  370  continuously interconnects ring gear member  334  with carrier member  326  and sun gear member  342 . The interconnecting member  370  may be one component or multiple components. The sun gear member  322  is continuously grounded to a housing  380  of the transmission  300  via a radially-extending structural member  381 . The housing  380  circumferentially surrounds the gear sets  320 ,  330  and  340  as well as the torque-transmitting mechanisms  350 ,  352 ,  354 ,  356 ,  357  and  358 . The transmission  300  further includes a first end wall  382  generally at one end of the transmission  300  and a second end wall  384  generally at an opposing end of the transmission  300 . The housing  380  joins the first and second end walls  382 ,  384 . It should be appreciated that the housing  380  and the first and second end walls  382 ,  384  form a transmission casing, and may be integrated, or may each be a separate component or components of the casing. The transmission casing may be referred to herein as  380 ,  382 ,  384 . The transmission casing  380 ,  382 ,  384  defines a cavity  385 . The end walls  382  and  384  enclose the cavity  385  axially, but are likely a conical or irregular shape rather than a planar shape as schematically depicted. 
     The planetary gear sets  320 ,  330 , and  340  and torque-transmitting mechanisms  350 ,  352 ,  354 ,  356 ,  357 , and  358  are located in the cavity  385 . The housing  380 , end walls  382  and  384  and the planetary gear sets  320 ,  330  and  340  cooperate to define five spaces or zones within the cavity  385 . A first zone I is defined between an outer surface  386  of the first end wall  382  and a plane  388  running generally parallel with a side of the planetary gear set  320  adjacent the first end wall  382 , and runs radially outward to a circumferential boundary  390  running along a radially-outermost surface of each of the ring gear members  324 ,  334  and  344 . A second zone II is defined between a plane  392  running generally parallel along a side of the planetary gear set  320  facing the planetary gear set  330 , a plane  394  running generally parallel along a side of the planetary gear set  330  facing the planetary gear set  320  and the circumferential boundary  390 . A third zone III is defined between a plane  395  running generally parallel along a side of the planetary gear set  330  facing the planetary gear set  340 , a plane  396  running generally parallel along a side of the planetary gear set  340  facing the planetary gear set  330  and the circumferential boundary  390 . A fourth zone IV is defined between a plane  397  running generally parallel along a side of the planetary gear set  340  facing the second end wall  384 , an outer surface  398  of the second end wall  384  and the circumferential boundary  390 . A fifth zone V is defined between the circumferential boundary  390 , an outer surface  399  of the housing  380 , and the outer surfaces  386  and  398  of the first and second end walls  382  and  384 , respectively. The structural member  381  traverses zones I and V. 
     Torque-transmitting mechanisms  350 ,  352 ,  354 , and  356  are rotating-type clutches and torque-transmitting mechanisms  357  and  358  are brakes, also referred to as reaction clutches. Torque-transmitting mechanism  350  is selectively engagable to connect the carrier member  336  for common rotation with the ring gear member  324 . The torque-transmitting mechanism  352  is selectively engagable to connect the input member  312  and the sun gear member  332  for common rotation with the ring gear member  324 . The torque-transmitting mechanism  354  is selectively engagable to connect the carrier member  336  for common rotation with the carrier member  346 . The torque-transmitting mechanism  356  is selectively engagable to connect the input member  312  and the sun gear member  332  for common rotation with the carrier member  346 . The torque-transmitting mechanism  357  is selectively engagable to ground the carrier member  326  (as well as the sun gear member  342  and ring gear member  334 ) to the transmission housing  380  via the structural member  381 . The torque-transmitting mechanism  358  is selectively engagable to ground the carrier member  346  to the transmission housing  380  via the structural member  381 . 
     The transmission  300  provides eight forward speed ratios and one reverse speed ratio between the input member  312  and the output member  314 . Specifically, a reverse speed ratio is established by engaging torque-transmitting mechanisms  352  and  358 ; a first forward speed ratio is established by engaging torque-transmitting mechanisms  354  and  358 ; a second forward speed ratio is established by engaging torque-transmitting mechanisms  354  and  357 ; a third forward speed ratio is established by engaging torque-transmitting mechanisms  350  and  354 ; a fourth forward speed ratio is established by engaging torque-transmitting mechanisms  352  and  354 ; a fifth forward speed ratio is established by engaging torque-transmitting mechanisms  354  and  356 ; a sixth forward speed ratio is established by engaging torque-transmitting mechanisms  352  and  356 ; a seventh forward speed ratio is established by engaging torque-transmitting mechanisms  350  and  356 ; and an eighth forward speed ratio is established by engaging torque-transmitting mechanisms  356  and  357 . 
     As shown in  FIG. 4A , torque-transmitting mechanism  357  is located in zone I; torque-transmitting mechanism  352  is located in zone II; torque-transmitting mechanism  354  is disposed in zone III; torque-transmitting mechanism  356  is disposed in zone IV; and torque-transmitting mechanisms  350  and  358  are disposed in zone V. Alternatively, the interconnections between the various gear members, the input member  312 , the output member  314  and the housing  380  obtained by selective engagement of the various torque-transmitting mechanism as described above are possible with the torque-transmitting mechanisms  350 ,  352 ,  354 ,  356 ,  357  and  358  disposed in other zones as shown in the chart of  FIG. 4B . An “X” in the chart of  FIG. 4B  indicates that the particular torque-transmitting mechanism is positionable in the referenced zone and an “O” indicates that the particular torque-transmitting mechanisms are not to be located in the referenced zone. It should be appreciated that the selection of location for the torque-transmitting mechanism of each row in the chart of  FIG. 4B  is feasible independently of the other rows. Accordingly, torque-transmitting mechanism  350  is locatable in any of three possible zones; torque-transmitting mechanism  352  is locatable if any of three possible zones; torque-transmitting mechanism  354  is locatable in any of two possible zones; torque transmitting mechanism  356  is locatable in any of two possible zones; torque-transmitting mechanism  357  is locatable in any of four possible zones; and torque-transmitting mechanism  358  is locatable in any of the five possible zones. 
     A fifth embodiment of a transmission  400  within the scope of the invention is shown in  FIG. 5A . Transmission  400  has an input member  412  for receiving power from a power source such as an internal combustion engine and output member  414  for delivering power to a final drive mechanism such as the wheels of a vehicle. 
     The transmission  400  includes a gearing arrangement  416  having three planetary gear sets  420 ,  430  and  440  and six selectively engagable torque-transmitting mechanisms  450 ,  452 ,  454 ,  456 ,  457  and  458 . In the embodiment of  FIG. 5A , planetary gear set  420  is the first planetary gear set, planetary gear set  440  is the second planetary gear set, and planetary gear set  430  is the third planetary gear set. 
     Each planetary gear set  420 ,  430  and  440  includes rotatable components concentric with a centerline  460  of the transmission  400 . Specifically, planetary gear set  420  includes a sun gear member  422 , a ring gear member  424  and a carrier member  426  that rotatably supports a plurality of pinion gears  427  that intermesh with both the sun gear member  422  and the ring gear member  424 . Planetary gear set  430  includes a sun gear member  432 , a ring gear member  434  and a carrier member  436  that rotatably supports a plurality of pinion gears  437  that intermesh with both the sun gear member  432  and the ring gear member  434 . Planetary gear set  440  includes a sun gear member  442 , a ring gear member  444  and a carrier member  446  that rotatably supports a plurality of pinion gears  447  that intermesh with both the sun gear member  442  and the ring gear member  444 . 
     The input member  412  is continuously connected for common rotation with sun gear member  432 . The output member  414  is continuously connected for common rotation with ring gear member  444 . An interconnecting member  470  continuously interconnects ring gear member  434  with carrier member  426  and sun gear member  442 . The interconnecting member  470  may be one component or multiple components. The sun gear member  422  is continuously grounded to a housing  480  of the transmission  400  via a radially-extending structural member  481 . The housing  480  circumferentially surrounds the gear sets  420 ,  430  and  440  as well as the torque-transmitting mechanisms  450 ,  452 ,  454 ,  456 ,  457  and  458 . The transmission  400  further includes a first end wall  482  generally at one end of the transmission  400  and a second end wall  484  generally at an opposing end of the transmission  400 . The housing  480  joins the first and second end walls  482 ,  484 . It should be appreciated that the housing  480  and the first and second end walls  482 ,  484  form a transmission casing, and may be integrated, or may each be a separate component or components of the casing. The transmission casing may be referred to herein as  480 ,  482 ,  484 . The transmission casing  480 ,  482 ,  484  defines a cavity  485 . The end walls  482  and  484  enclose the cavity  485  axially, but are likely a conical or irregular shape rather than a planar shape as schematically depicted. 
     The planetary gear sets  420 ,  430 , and  440  and torque-transmitting mechanisms  450 ,  452 ,  454 ,  456 ,  457 , and  458  are located in the cavity  485 . The housing  480 , end walls  482  and  484  and the planetary gear sets  420 ,  430  and  440  cooperate to define five spaces or zones within the cavity  485 . A first zone I is defined between an outer surface  486  of the first end wall  482  and a plane  488  running generally parallel with a side of the planetary gear set  420  adjacent the first end wall  482 , and runs radially outward to a circumferential boundary  490  running along a radially-outermost periphery of each of the ring gear members  424 ,  434  and  444 . A second zone II is defined between a plane  492  running generally parallel along a side of the planetary gear set  420  facing the planetary gear set  430 , a plane  494  running generally parallel along a side of the planetary gear set  430  facing the planetary gear set  420  and the circumferential boundary  490 . A third zone III is defined between a plane  495  running generally parallel along a side of the planetary gear set  430  facing the planetary gear set  440 , a plane  496  running generally parallel along a side of the planetary gear set  440  facing the planetary gear set  430  and the circumferential boundary  490 . A fourth zone IV is defined between a plane  497  running generally parallel along a side of the planetary gear set  440  facing the second end wall  484 , an outer surface  498  of the second end wall  484  and the circumferential boundary  490 . A fifth zone V is defined between the circumferential boundary  490 , an outer surface  499  of the housing  480 , and the outer surfaces  486  and  498  of the first and second end walls  482  and  484 , respectively. The structural member  481  traverses zones II and V. 
     Torque-transmitting mechanisms  450 ,  452 ,  454 , and  456  are rotating-type clutches and torque-transmitting mechanisms  457  and  458  are brakes, also referred to as reaction clutches. Torque-transmitting mechanism  450  is selectively engagable to connect the carrier member  436  for common rotation with the ring gear member  424 . The torque-transmitting mechanism  452  is selectively engagable to connect the input member  412  and the sun gear member  432  for common rotation with the ring gear member  424 . The torque-transmitting mechanism  454  is selectively engagable to connect the carrier member  436  for common rotation with the carrier member  446 . The torque-transmitting mechanism  456  is selectively engagable to connect the input member  412  and the sun gear member  432  for common rotation with the carrier member  446 . The torque-transmitting mechanism  457  is selectively engagable to ground the carrier member  426  (as well as the sun gear member  442  and ring gear member  434 ) to the transmission housing  480  via the structural member  481 . The torque-transmitting mechanism  458  is selectively engagable to ground the carrier member  446  to the transmission housing  480  via the structural member  481 . 
     The transmission  400  provides eight forward speed ratios and one reverse speed ratio between the input member  412  and the output member  414 . Specifically, a reverse speed ratio is established by engaging torque-transmitting mechanisms  452  and  458 ; a first forward speed ratio is established by engaging torque-transmitting mechanisms  454  and  458 ; a second forward speed ratio is established by engaging torque-transmitting mechanisms  454  and  457 ; a third forward speed ratio is established by engaging torque-transmitting mechanisms  450  and  454 ; a fourth forward speed ratio is established by engaging torque-transmitting mechanisms  452  and  454 ; a fifth forward speed ratio is established by engaging torque-transmitting mechanisms  454  and  456 ; a sixth forward speed ratio is established by engaging torque-transmitting mechanisms  452  and  456 ; a seventh forward speed ratio is established by engaging torque-transmitting mechanisms  450  and  456 ; and an eighth forward speed ratio is established by engaging torque-transmitting mechanisms  456  and  457 . 
     As shown in  FIG. 5A , torque-transmitting mechanism  452  is located in zone I; torque-transmitting mechanisms  450  and  457  are located in zone II; torque-transmitting mechanism  454  is disposed in zone III; torque-transmitting mechanism  456  is disposed in zone IV; and torque-transmitting mechanism  458  is disposed in zone V. Alternatively, the interconnections between the various gear members, the input member  412 , the output member  414  and the housing  480  obtained by selective engagement of the various torque-transmitting mechanism as described above are possible with the torque-transmitting mechanisms  450 ,  452 ,  454 ,  456 ,  457  and  458  disposed in other zones as shown in the chart of  FIG. 5B . An “X” in the chart of  FIG. 5B  indicates that the particular torque-transmitting mechanism is positionable in the referenced zone and an “O” indicates that the particular torque-transmitting mechanisms are not to be located in the referenced zone. It should be appreciated that the selection of location for the torque-transmitting mechanism of each row in the chart of  FIG. 5B  is feasible independently of the other rows. Accordingly, torque-transmitting mechanism  450  is locatable in any of three possible zones; torque-transmitting mechanism  452  is locatable in any of three possible zones; torque-transmitting mechanism  454  is locatable in any of two possible zones; torque transmitting mechanism  456  is locatable in any of two possible zones; torque-transmitting mechanism  457  is locatable in any of the five possible zones; and torque-transmitting mechanism  458  is locatable in any of four possible zones. 
     A sixth embodiment of a transmission  500  within the scope of the invention is shown in  FIG. 6A . Transmission  500  has an input member  512  for receiving power from a power source such as an internal combustion engine and output member  514  for delivering power to a final drive mechanism such as the wheels of a vehicle. Both the input member  512  and the output member  514  extend through a first end wall  582  of the transmission  500 . 
     The transmission  500  includes a gearing arrangement  516  having three planetary gear sets  520 ,  530  and  540  and six selectively engagable torque-transmitting mechanisms  550 ,  552 ,  554 ,  556 ,  557  and  558 . In the embodiment of  FIG. 6A , planetary gear set  530  is the first planetary gear set, planetary gear set  520  is the second planetary gear set, and planetary gear set  540  is the third planetary gear set. 
     Each planetary gear set  520 ,  530  and  540  includes rotatable components concentric with a centerline  560  of the transmission  500 . Specifically, planetary gear set  520  includes a sun gear member  522 , a ring gear member  524  and a carrier member  526  that rotatably supports a plurality of pinion gears  527  that intermesh with both the sun gear member  522  and the ring gear member  524 . Planetary gear set  530  includes a sun gear member  532 , a ring gear member  534  and a carrier member  536  that rotatably supports a plurality of pinion gears  537  that intermesh with both the sun gear member  532  and the ring gear member  534 . Planetary gear set  540  includes a sun gear member  542 , a ring gear member  544  and a carrier member  546  that rotatably supports a plurality of pinion gears  547  that intermesh with both the sun gear member  542  and the ring gear member  544 . 
     The input member  512  is continuously connected for common rotation with sun gear member  542 . The output member  514  is continuously connected for common rotation with ring gear member  524 . An interconnecting member  570  continuously interconnects ring gear member  544  with carrier member  536  and sun gear member  522 . The interconnecting member  570  may be one component or multiple components. The sun gear member  532  is continuously grounded to a housing  580  of the transmission  500  via a radially-extending structural member  581 . The housing  580  circumferentially surrounds the gear sets  520 ,  530  and  540  as well as the torque-transmitting mechanisms  550 ,  552 ,  554 ,  556 ,  557  and  558 . The transmission  500  further includes a first end wall  582  generally at one end of the transmission  500  and a second end wall  584  generally at an opposing end of the transmission  500 . The housing  580  joins the first and second end walls  582 ,  584 . It should be appreciated that the housing  580  and the first and second end walls  582 ,  584  form a transmission casing, and may be integrated, or may each be a separate component or components of the casing. The transmission casing may be referred to herein as  580 ,  582 ,  584 . The transmission casing  580 ,  582 ,  584  defines a cavity  585 . The end walls  582  and  584  enclose the cavity  585  axially, but are likely a conical or irregular shape rather than a planar shape as schematically depicted. 
     The planetary gear sets  520 ,  530 , and  540  and torque-transmitting mechanisms  550 ,  552 ,  554 ,  556 ,  557 , and  558  are located in the cavity  585 . The housing  580 , end walls  582  and  584  and the planetary gear sets  520 ,  530  and  540  cooperate to define five spaces or zones within the cavity  585 . A first zone I is defined between an outer surface  586  of the first end wall  582  and a plane  588  running generally parallel with a side of the planetary gear set  520  adjacent the first end wall  582 , and runs radially outward to a circumferential boundary  590  running along a radially-outermost periphery of each of the ring gear members  524 ,  534  and  544 . A second zone II is defined between a plane  592  running generally parallel along a side of the planetary gear set  520  facing the planetary gear set  530 , a plane  594  running generally parallel along a side of the planetary gear set  530  facing the planetary gear set  520  and the circumferential boundary  590 . A third zone III is defined between a plane  595  running generally parallel along a side of the planetary gear set  530  facing the planetary gear set  540 , a plane  596  running generally parallel along a side of the planetary gear set  540  facing the planetary gear set  530  and the circumferential boundary  590 . A fourth zone IV is defined between a plane  597  running generally parallel along a side of the planetary gear set  540  facing the second end wall  584 , an outer surface  598  of the second end wall  584  and the circumferential boundary  590 . A fifth zone V is defined between the circumferential boundary  590 , an outer surface  599  of the housing  580 , and the outer surfaces  586  and  598  of the first and second end walls  582  and  584 , respectively. The structural member  581  traverses zones II and V. 
     Torque-transmitting mechanisms  550 ,  552 ,  554 , and  556  are rotating-type clutches and torque-transmitting mechanisms  557  and  558  are brakes, also referred to as reaction clutches. Torque-transmitting mechanism  550  is selectively engagable to connect the carrier member  546  for common rotation with the ring gear member  534 . The torque-transmitting mechanism  552  is selectively engagable to connect the input member  512  and the sun gear member  542  for common rotation with the ring gear member  534 . The torque-transmitting mechanism  554  is selectively engagable to connect the carrier member  526  for common rotation with the carrier member  546 . The torque-transmitting mechanism  556  is selectively engagable to connect the input member  512  and the sun gear member  542  for common rotation with the carrier member  526 . The torque-transmitting mechanism  557  is selectively engagable to ground the carrier member  536  (as well as the sun gear member  522  and ring gear member  544 ) to the transmission housing  580  via the structural member  581 . The torque-transmitting mechanism  558  is selectively engagable to ground the carrier member  526  to the transmission housing  580  via the structural member  581 . 
     The transmission  500  provides eight forward speed ratios and one reverse speed ratio between the input member  512  and the output member  514 . Specifically, a reverse speed ratio is established by engaging torque-transmitting mechanisms  552  and  558 ; a first forward speed ratio is established by engaging torque-transmitting mechanisms  554  and  558 ; a second forward speed ratio is established by engaging torque-transmitting mechanisms  554  and  557 ; a third forward speed ratio is established by engaging torque-transmitting mechanisms  550  and  554 ; a fourth forward speed ratio is established by engaging torque-transmitting mechanisms  552  and  554 ; a fifth forward speed ratio is established by engaging torque-transmitting mechanisms  554  and  556 ; a sixth forward speed ratio is established by engaging torque-transmitting mechanisms  552  and  556 ; a seventh forward speed ratio is established by engaging torque-transmitting mechanisms  550  and  556 ; and an eighth forward speed ratio is established by engaging torque-transmitting mechanisms  556  and  557 . 
     As shown in  FIG. 6A , torque-transmitting mechanisms  554  and  556  are located in zone I; torque-transmitting mechanisms  557  and  558  are located in zone II; and torque-transmitting mechanisms  550  and  552  are disposed in zone IV. Alternatively, the interconnections between the various gear members, the input member  512 , the output member  514  and the housing  580  obtained by selective engagement of the various torque-transmitting mechanism as described above are possible with the torque-transmitting mechanisms  550 ,  552 ,  554 ,  556 ,  557  and  558  disposed in other zones as shown in the chart of  FIG. 6B . An “X” in the chart of  FIG. 6B  below indicates that the particular torque-transmitting mechanism is positionable in the referenced zone and an “O” indicates that the particular torque-transmitting mechanisms are not to be located in the referenced zone. It should be appreciated that the selection of location for the torque-transmitting mechanism of each row in the chart of  FIG. 6B  is feasible independently of the other rows. Accordingly, torque-transmitting mechanism  550  is locatable in any of four possible zones; torque-transmitting mechanism  552  is locatable if any of four possible zones; torque-transmitting mechanism  554  is locatable in any of three possible zones; torque transmitting mechanism  556  is locatable in any of three possible zones; torque-transmitting mechanism  557  is locatable in any of four possible zones; and torque-transmitting mechanism  558  is locatable in any of three possible zones. 
     A seventh embodiment of a transmission  600  within the scope of the invention is shown in  FIG. 7A . Transmission  600  has an input member  612  for receiving power from a power source such as an internal combustion engine and output member  614  for delivering power to a final drive mechanism such as the wheels of a vehicle. 
     The transmission  600  includes a gearing arrangement  616  having three planetary gear sets  620 ,  630  and  640  and six selectively engagable torque-transmitting mechanisms  650 ,  652 ,  654 ,  656 ,  657  and  658 . In the embodiment of  FIG. 7A , planetary gear set  620  is the first planetary gear set, planetary gear set  630  is the second planetary gear set, and planetary gear set  640  is the third planetary gear set. 
     Each planetary gear set  620 ,  630  and  640  includes rotatable components concentric with a centerline  660  of the transmission  600 . Specifically, planetary gear set  620  includes a sun gear member  622 , a ring gear member  624  and a carrier member  626  that rotatably supports a plurality of pinion gears  627  that intermesh with both the sun gear member  622  and the ring gear member  624 . Planetary gear set  630  includes a sun gear member  632 , a ring gear member  634  and a carrier member  636  that rotatably supports a plurality of pinion gears  637  that intermesh with both the sun gear member  632  and the ring gear member  634 . Planetary gear set  640  includes a sun gear member  642 , a ring gear member  644  and a carrier member  646  that rotatably supports a plurality of pinion gears  647  that intermesh with both the sun gear member  642  and the ring gear member  644 . 
     The input member  612  is continuously connected for common rotation with sun gear member  642 . The output member  614  is continuously connected for common rotation with ring gear member  634 . An interconnecting member  670  continuously interconnects ring gear member  644  with carrier member  626  and sun gear member  632 . The interconnecting member  670  may be one component or multiple components. The sun gear member  622  is continuously grounded to a housing  680  of the transmission  600  via a radially-extending structural member  681 . The housing  680  circumferentially surrounds the gear sets  620 ,  630  and  640  as well as the torque-transmitting mechanisms  650 ,  652 ,  654 ,  656 ,  657  and  658 . The transmission  600  further includes a first end wall  682  generally at one end of the transmission  600  and a second end wall  684  generally at an opposing end of the transmission  600 . The housing  680  joins the first and second end walls  682 ,  684 . It should be appreciated that the housing  680  and the first and second end walls  682 ,  684  form a transmission casing, and may be integrated, or may each be a separate component or components of the casing. The transmission casing may be referred to herein as  680 ,  682 ,  684 . The transmission casing  680 ,  682 ,  684  defines a cavity  685 . The end walls  682  and  684  enclose the cavity  685  axially, but are likely a conical or irregular shape rather than a planar shape as schematically depicted. 
     The planetary gear sets  620 ,  630 , and  640  and torque-transmitting mechanisms  650 ,  652 ,  654 ,  656 ,  657 , and  658  are located in the cavity  685 . 
     The housing  680 , end walls  682  and  684  and the planetary gear sets  620 ,  630  and  640  cooperate to define five spaces or zones in the cavity  685 . A first zone I is defined between an outer surface  686  of the first end wall  682  and a plane  688  running generally parallel with a side of the planetary gear set  620  adjacent the first end wall  682 , and runs radially outward to a circumferential boundary  690  running along a radially-outermost periphery of each of the ring gear members  624 ,  634  and  644 . A second zone II is defined between a plane  692  running generally parallel along a side of the planetary gear set  620  facing the planetary gear set  630 , a plane  694  running generally parallel along a side of the planetary gear set  630  facing the planetary gear set  620  and the circumferential boundary  690 . A third zone III is defined between a plane  695  running generally parallel along a side of the planetary gear set  630  facing the planetary gear set  640 , a plane  696  running generally parallel along a side of the planetary gear set  640  facing the planetary gear set  630  and the circumferential boundary  690 . A fourth zone IV is defined between a plane  697  running generally parallel along a side of the planetary gear set  640  facing the second end wall  684 , an outer surface  698  of the second end wall  684  and the circumferential boundary  690 . A fifth zone V is defined between the circumferential boundary  690 , an outer surface  699  of the housing  680 , and the outer surfaces  686  and  698  of the first and second end walls  682  and  684 , respectively. The structural member  681  traverses zones I and V. 
     Torque-transmitting mechanisms  650 ,  652 ,  654 , and  656  are rotating-type clutches and torque-transmitting mechanisms  657  and  658  are brakes, also referred to as reaction clutches. Torque-transmitting mechanism  650  is selectively engagable to connect the carrier member  646  for common rotation with the ring gear member  624 . The torque-transmitting mechanism  652  is selectively engagable to connect the input member  612  and sun gear member  642  for common rotation with the ring gear member  624 . The torque-transmitting mechanism  654  is selectively engagable to connect the carrier member  636  for common rotation with the carrier member  646 . The torque-transmitting mechanism  656  is selectively engagable to connect the input member  612  and the sun gear member  642  for common rotation with the carrier member  636 . The torque-transmitting mechanism  657  is selectively engagable to ground the carrier member  626  (as well as the sun gear member  632  and ring gear member  644 ) to the transmission housing  680  via the structural member  681 . The torque-transmitting mechanism  658  is selectively engagable to ground the carrier member  636  to the transmission housing  680  via the structural member  681 . 
     The transmission  600  provides eight forward speed ratios and one reverse speed ratio between the input member  612  and the output member  614 . Specifically, a reverse speed ratio is established by engaging torque-transmitting mechanisms  652  and  658 ; a first forward speed ratio is established by engaging torque-transmitting mechanisms  654  and  658 ; a second forward speed ratio is established by engaging torque-transmitting mechanisms  654  and  657 ; a third forward speed ratio is established by engaging torque-transmitting mechanisms  650  and  654 ; a fourth forward speed ratio is established by engaging torque-transmitting mechanisms  652  and  654 ; a fifth forward speed ratio is established by engaging torque-transmitting mechanisms  654  and  656 ; a sixth forward speed ratio is established by engaging torque-transmitting mechanisms  652  and  656 ; a seventh forward speed ratio is established by engaging torque-transmitting mechanisms  650  and  656 ; and an eighth forward speed ratio is established by engaging torque-transmitting mechanisms  656  and  657 . 
     As shown in  FIG. 7A , torque-transmitting mechanism  657  is located in zone I; torque-transmitting mechanism  652  is located in zone II; torque-transmitting mechanism  650  is disposed in zone III; torque-transmitting mechanisms  654  and  656  are disposed in zone IV; and torque-transmitting mechanism  658  is disposed in zone V. Alternatively, the interconnections between the various gear members, the input member  612 , the output member  614  and the housing  680  obtained by selective engagement of the various torque-transmitting mechanism as described above are possible with the torque-transmitting mechanisms  650 ,  652 ,  654 ,  656 ,  657  and  658  disposed in other zones as shown in the chart of  FIG. 7B . An “X” in the chart of  FIG. 7B  indicates that the particular torque-transmitting mechanism is positionable in the referenced zone and an “O” indicates that the particular torque-transmitting mechanisms are not to be located in the referenced zone. It should be appreciated that the selection of location for the torque-transmitting mechanism of each row in the chart of  FIG. 7B  is feasible independently of the other rows. Accordingly, torque-transmitting mechanism  650  is locatable in any of three possible zones; torque-transmitting mechanism  652  is locatable if any of three possible zones; torque-transmitting mechanism  654  is locatable in any of three possible zones; torque transmitting mechanism  656  is locatable in any of three possible zones; torque-transmitting mechanism  657  is locatable in any of the three possible zones; and torque-transmitting mechanism  658  is locatable in any of three possible zones. 
     An eighth embodiment of a transmission  700  within the scope of the invention is shown in  FIG. 8A . Transmission  700  has an input member  712  for receiving power from a power source such as an internal combustion engine and output member  714  for delivering power to a final drive mechanism such as the wheels of a vehicle. Both the input member  712  and the output member  714  extend through a first end wall  782  of the transmission  700 . 
     The transmission  700  includes a gearing arrangement  716  having three planetary gear sets  720 ,  730  and  740  and six selectively engagable torque-transmitting mechanisms  750 ,  752 ,  754 ,  756 ,  757  and  758 . In the embodiment of  FIG. 8A , planetary gear set  740  is the first planetary gear set, planetary gear set  730  is the second planetary gear set, and planetary gear set  720  is the third planetary gear set. 
     Each planetary gear set  720 ,  730  and  740  includes rotatable components concentric with a centerline  760  of the transmission  700 . Specifically, planetary gear set  720  includes a sun gear member  722 , a ring gear member  724  and a carrier member  726  that rotatably supports a plurality of pinion gears  727  that intermesh with both the sun gear member  722  and the ring gear member  724 . Planetary gear set  730  includes a sun gear member  732 , a ring gear member  734  and a carrier member  736  that rotatably supports a plurality of pinion gears  737  that intermesh with both the sun gear member  732  and the ring gear member  734 . Planetary gear set  740  includes a sun gear member  742 , a ring gear member  744  and a carrier member  746  that rotatably supports a plurality of pinion gears  747  that intermesh with both the sun gear member  742  and the ring gear member  744 . 
     The input member  712  is continuously connected for common rotation with sun gear member  722 . The output member  714  is continuously connected for common rotation with ring gear member  734 . An interconnecting member  770  continuously interconnects ring gear member  724  with carrier member  746  and sun gear member  732 . The interconnecting member  770  may be one component or multiple components. The sun gear member  742  is continuously grounded to a housing  780  of the transmission  700  via a radially-extending structural member  781 . The housing  780  circumferentially surrounds the gear sets  720 ,  730  and  740  as well as the torque-transmitting mechanisms  750 ,  752 ,  754 ,  756 ,  757  and  758 . The transmission  700  further includes a first end wall  782  generally at one end of the transmission  700  and a second end wall  784  generally at an opposing end of the transmission  700 . The housing  780  joins the first and second end walls  782 ,  784 . It should be appreciated that the housing  80  and the first and second end walls  782 ,  784  form a transmission casing, and may be integrated, or may each be a separate component or components of the casing. The transmission casing may be referred to herein as  780 ,  782 ,  784 . The transmission casing  780 ,  782 ,  784  defines a cavity  785 . The end walls  782  and  784  enclose the cavity  785  axially, but are likely a conical or irregular shape rather than a planar shape as schematically depicted. 
     The planetary gear sets  720 ,  730 , and  740  and torque-transmitting mechanisms  750 ,  752 ,  754 ,  756 ,  757 , and  758  are located in the cavity  785 . The housing  780 , end walls  782  and  784  and the planetary gear sets  720 ,  730  and  740  cooperate to define five spaces or zones in the cavity  785 . A first zone I is defined between an outer surface  786  of the first end wall  782  and a plane  788  running generally parallel with a side of the planetary gear set  720  adjacent the first end wall  782 , and runs radially outward to a circumferential boundary  790  running along a radially-outermost periphery of each of the ring gear members  724 ,  734  and  744 . A second zone II is defined between a plane  792  running generally parallel along a side of the planetary gear set  720  facing the planetary gear set  730 , a plane  794  running generally parallel along a side of the planetary gear set  730  facing the planetary gear set  720  and the circumferential boundary  790 . A third zone III is defined between a plane  795  running generally parallel along a side of the planetary gear set  730  facing the planetary gear set  740 , a plane  796  running generally parallel along a side of the planetary gear set  740  facing the planetary gear set  530  and the circumferential boundary  790 . A fourth zone IV is defined between a plane  797  running generally parallel along a side of the planetary gear set  740  facing the second end wall  784 , an outer surface  798  of the second end wall  784  and the circumferential boundary  790 . A fifth zone V is defined between the circumferential boundary  790 , an outer surface  799  of the housing  780 , and the outer surfaces  786  and  798  of the first and second end walls  782  and  784 , respectively. The structural member  781  traverses zones III and V. 
     Torque-transmitting mechanisms  750 ,  752 ,  754 , and  756  are rotating-type clutches and torque-transmitting mechanisms  757  and  758  are brakes, also referred to as reaction clutches. Torque-transmitting mechanism  750  is selectively engagable to connect the carrier member  726  for common rotation with the ring gear member  744 . The torque-transmitting mechanism  752  is selectively engagable to connect the input member  712  and the sun gear member  722  for common rotation with the ring gear member  744 . The torque-transmitting mechanism  754  is selectively engagable to connect the carrier member  726  for common rotation with the carrier member  736 . The torque-transmitting mechanism  756  is selectively engagable to connect the input member  712  and the sun gear member  722  for common rotation with the carrier member  736 . The torque-transmitting mechanism  757  is selectively engagable to ground the carrier member  746  (as well as the sun gear member  732  and ring gear member  724 ) to the transmission housing  780  via the structural member  781 . The torque-transmitting mechanism  758  is selectively engagable to ground the carrier member  736  to the transmission housing  780  via the structural member  781 . 
     The transmission  700  provides eight forward speed ratios and one reverse speed ratio between the input member  712  and the output member  714 . Specifically, a reverse speed ratio is established by engaging torque-transmitting mechanisms  752  and  758 ; a first forward speed ratio is established by engaging torque-transmitting mechanisms  754  and  758 ; a second forward speed ratio is established by engaging torque-transmitting mechanisms  754  and  757 ; a third forward speed ratio is established by engaging torque-transmitting mechanisms  750  and  754 ; a fourth forward speed ratio is established by engaging torque-transmitting mechanisms  752  and  754 ; a fifth forward speed ratio is established by engaging torque-transmitting mechanisms  754  and  756 ; a sixth forward speed ratio is established by engaging torque-transmitting mechanisms  752  and  756 ; a seventh forward speed ratio is established by engaging torque-transmitting mechanisms  750  and  756 ; and an eighth forward speed ratio is established by engaging torque-transmitting mechanisms  756  and  757 . 
     As shown in  FIG. 8A , torque-transmitting mechanisms  754  and  756  are located in zone I; and torque-transmitting mechanisms  750 ,  752 ,  757  and  758  are located in zone III. Alternatively, the interconnections between the various gear members, the input member  712 , the output member  714  and the housing  780  obtained by selective engagement of the various torque-transmitting mechanism as described above are possible with the torque-transmitting mechanisms  750 ,  752 ,  754 ,  756 ,  757  and  758  disposed in other zones as shown in the chart of  FIG. 8B  below. An “X” in the chart of  FIG. 8B  indicates that the particular torque-transmitting mechanism is positionable in the referenced zone and an “O” indicates that the particular torque-transmitting mechanisms are not to be located in the referenced zone. It should be appreciated that the selection of location for the torque-transmitting mechanism of each row in the chart of  FIG. 8B  is feasible independently of the other rows. Accordingly, torque-transmitting mechanism  750  is locatable in any of three possible zones; torque-transmitting mechanism  752  is locatable if any of three possible zones; torque-transmitting mechanism  754  is locatable in any of three possible zones; torque transmitting mechanism  756  is locatable in any of three possible zones; torque-transmitting mechanism  757  is locatable in any of four possible zones; and torque-transmitting mechanism  758  is locatable in any of three possible zones. 
     A ninth embodiment of a transmission  800  within the scope of the invention is shown in  FIG. 9A . Transmission  800  has an input member  812  for receiving power from a power source such as an internal combustion engine and output member  814  for delivering power to a final drive mechanism such as the wheels of a vehicle. 
     The transmission  800  includes a gearing arrangement  816  having three planetary gear sets  820 ,  830  and  840  and six selectively engagable torque-transmitting mechanisms  850 ,  852 ,  854 ,  856 ,  857  and  858 . In the embodiment of  FIG. 9A , planetary gear set  820  is the first planetary gear set, planetary gear set  830  is the second planetary gear set, and planetary gear set  840  is the third planetary gear set. 
     Each planetary gear set  820 ,  830  and  840  includes rotatable components concentric with a centerline  860  of the transmission  800 . Specifically, planetary gear set  820  includes a sun gear member  822 , a ring gear member  824  and a carrier member  826  that rotatably supports a plurality of pinion gears  827  that intermesh with both the sun gear member  822  and the ring gear member  824 . Planetary gear set  830  includes a sun gear member  832 , a ring gear member  834  and a carrier member  836  that rotatably supports a plurality of pinion gears  837  that intermesh with both the sun gear member  832  and the ring gear member  834 . Planetary gear set  840  includes a sun gear member  842 , a ring gear member  844  and a carrier member  846  that rotatably supports a plurality of pinion gears  847  that intermesh with both the sun gear member  842  and the ring gear member  844 . 
     The input member  812  is continuously connected for common rotation with sun gear member  842 . The output member  814  is continuously connected for common rotation with ring gear member  834 . An interconnecting member  870  continuously interconnects ring gear member  844  with carrier member  826  and sun gear member  832 . The interconnecting member  870  may be one component or multiple components. The sun gear member  822  is continuously grounded to a housing  880  of the transmission  800  via a radially-extending structural member  881 . The housing  880  circumferentially surrounds the gear sets  820 ,  830  and  840  as well as the torque-transmitting mechanisms  850 ,  852 ,  854 ,  856 ,  857  and  858 . The transmission  800  further includes a first end wall  882  generally at one end of the transmission  800  and a second end wall  884  generally at an opposing end of the transmission  800 . The housing  880  joins the first and second end walls  882 ,  884 . It should be appreciated that the housing  880  and the first and second end walls  882 ,  884  form a transmission casing, and may be integrated, or may each be a separate component or components of the casing. The transmission casing may be referred to herein as  880 ,  882 ,  884 . The transmission casing  880 ,  882 ,  884  defines a cavity  885 . The end walls  882  and  884  enclose the cavity  885  axially, but are likely a conical or irregular shape rather than a planar shape as schematically depicted. 
     The planetary gear sets  820 ,  830 , and  840  and torque-transmitting mechanisms  850 ,  852 ,  854 ,  856 ,  857 , and  858  are located in the cavity  885 . The housing  880 , end walls  882  and  884  and the planetary gear sets  820 ,  830  and  840  cooperate to define five spaces or zones in the cavity  885 . A first zone I is defined between an outer surface  886  of the first end wall  882  and a plane  888  running generally parallel with a side of the planetary gear set  820  adjacent the first end wall  882 , and runs radially outward to a circumferential boundary  890  running along a radially-outermost periphery of each of the ring gear members  824 ,  834  and  844 . A second zone II is defined between a plane  892  running generally parallel along a side of the planetary gear set  820  facing the planetary gear set  830 , a plane  894  running generally parallel along a side of the planetary gear set  830  facing the planetary gear set  820  and the circumferential boundary  890 . A third zone III is defined between a plane  895  running generally parallel along a side of the planetary gear set  830  facing the planetary gear set  840 , a plane  896  running generally parallel along a side of the planetary gear set  840  facing the planetary gear set  830  and the circumferential boundary  890 . A fourth zone IV is defined between a plane  897  running generally parallel along a side of the planetary gear set  840  facing the second end wall  884 , an outer surface  898  of the second end wall  884  and the circumferential boundary  890 . A fifth zone V is defined between the circumferential boundary  890 , an outer surface  899  of the housing  880 , and the outer surfaces  886  and  898  of the first and second end walls  882  and  884 , respectively. The structural member  881  traverses zones II and V. 
     Torque-transmitting mechanisms  850 ,  852 ,  854 , and  856  are rotating-type clutches and torque-transmitting mechanisms  857  and  858  are brakes, also referred to as reaction clutches. Torque-transmitting mechanism  850  is selectively engagable to connect the carrier member  846  for common rotation with the ring gear member  824 . The torque-transmitting mechanism  852  is selectively engagable to connect the input member  812  for common rotation with the ring gear member  824 . The torque-transmitting mechanism  854  is selectively engagable to connect the carrier member  846  for common rotation with the carrier member  836 . The torque-transmitting mechanism  856  is selectively engagable to connect the input member  812  and the sun gear member  842  for common rotation with the carrier member  836 . The torque-transmitting mechanism  857  is selectively engagable to ground the carrier member  826  (as well as the sun gear member  832  and ring gear member  844 ) to the transmission housing  880  via the structural member  881 . The torque-transmitting mechanism  858  is selectively engagable to ground the carrier member  836  to the transmission housing  880  via the structural member  881 . 
     The transmission  800  provides eight forward speed ratios and one reverse speed ratio between the input member  812  and the output member  814 . Specifically, a reverse speed ratio is established by engaging torque-transmitting mechanisms  852  and  858 ; a first forward speed ratio is established by engaging torque-transmitting mechanisms  854  and  858 ; a second forward speed ratio is established by engaging torque-transmitting mechanisms  854  and  857 ; a third forward speed ratio is established by engaging torque-transmitting mechanisms  850  and  854 ; a fourth forward speed ratio is established by engaging torque-transmitting mechanisms  852  and  854 ; a fifth forward speed ratio is established by engaging torque-transmitting mechanisms  854  and  856 ; a sixth forward speed ratio is established by engaging torque-transmitting mechanisms  852  and  856 ; a seventh forward speed ratio is established by engaging torque-transmitting mechanisms  850  and  856 ; and an eighth forward speed ratio is established by engaging torque-transmitting mechanisms  856  and  857 . 
     As shown in  FIG. 9A , torque-transmitting mechanism  852  is located in zone I; torque-transmitting mechanisms  857  and  858  are located in zone II; torque-transmitting mechanism  850  is disposed in zone III; and torque-transmitting mechanisms  854  and  856  are disposed in zone IV. Alternatively, the interconnections between the various gear members, the input member  812 , the output member  814  and the housing  880  obtained by selective engagement of the various torque-transmitting mechanism as described above are possible with the torque-transmitting mechanisms  850 ,  852 ,  854 ,  856 ,  857  and  858  disposed in other zones as shown in the chart of  FIG. 9B . An “X” in the chart of  FIG. 9B  indicates that the particular torque-transmitting mechanism is positionable in the referenced zone and an “O” indicates that the particular torque-transmitting mechanisms are not to be located in the referenced zone. It should be appreciated that the selection of location for the torque-transmitting mechanism of each row in the chart of  FIG. 9B  is feasible independently of the other rows. Accordingly, torque-transmitting mechanism  850  is locatable in any of four possible zones; torque-transmitting mechanism  852  is locatable if any of four possible zones; torque-transmitting mechanism  854  is locatable in any of three possible zones; torque transmitting mechanism  856  is locatable in any of three possible zones; torque-transmitting mechanism  857  is locatable in any of the three possible zones; and torque-transmitting mechanism  858  is locatable in any of two possible zones. 
     While the best modes for carrying out the invention have been described in detail, those familiar with the art to which this invention relates will recognize various alternative designs and embodiments for practicing the invention within the scope of the appended claims.