Abstract:
The backrest for motorcyclists includes a base plate with a pivoting and telescoping strut extending from its forward end. The upper end of the strut has a cushioned seatback pivotally attached thereto. The strut is adjustable to optimize the seatback height. The fore and aft angle of the strut, and thus the angular position of the seatback, is adjusted by an adjustable stop at the base of the strut. The stop limits the rearward angular motion of the strut, but allows the strut to pivot forward against the seating surface to facilitate mounting and dismounting of the motorcycle. The base plate is removably secured to the seat by lateral straps that hook beneath the edges of the seat. The span of the straps may be adjusted by laterally telescoping strap brackets extending from the plate. The bottom of the plate is coated with a non-slip material for greater security.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the benefit of U.S. Provisional Patent Application Ser. No. 61/272,903, filed Nov. 17, 2009. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates generally to seating for motor vehicles, and particularly to a backrest for motorcycles, which provides an adjustable backrest that may be removably secured to a conventional motorcycle seat without modification of the seat to provide additional support and comfort to the cyclist. 
         [0004]    2. Description of the Related Art 
         [0005]    The conventional motorcycle has an elongate and relatively narrow seat that is straddled by the cyclist during operation, and also by the passenger if a passenger happens to accompany the cyclist. Conventional motorcycle seats are not provided with any form of back support, as the need for back support is not considered critical by most motorcycle manufacturers. While some exceptions occur, particularly in higher end motorcycles, the above is generally true with motorcycles built primarily for the transport of a single operator and for speed and handling qualities. 
         [0006]    As a result, many customized motorcycles have been constructed with seat back support, particularly in the form of so-called “sissy bars” for the rear passenger. Such bars are often more of a style statement than a practical support for the passenger, but other seat backrests have also been developed for the operator of the motorcycle as well. These various motorcycle operator backrests are generally permanently installed, and even those that are removable generally require some permanent modification to the motorcycle in the form of drilled holes, weldments, added brackets, etc. Moreover, even when installed, such backrests do not provide the range of adjustment in terms of fore and aft positioning, height adjustment, and angular rake adjustment that would be desired to suit a wide range of different riders and/or conditions. 
         [0007]    The present inventor is aware of various motorcycle seat backrests that have been developed in the past. An example of such is found in Canadian Patent Publication No. 2,304,455 published on Nov. 1, 2001 to Mario Leblanc et al. According to the drawings (no English abstract or translation was provided), the device of the &#39;455 Canadian Patent Publication comprises a backrest supported on an arm, the arm being adjustably mounted atop a bracket. The base of the bracket appears to have a plurality of attachment holes therein, but no attachment or environmental view is illustrated. 
         [0008]    Thus, a backrest for motorcyclists solving the aforementioned problems is desired. 
       SUMMARY OF THE INVENTION 
       [0009]    The backrest for motorcyclists provides support for the lower or mid-back of the cycle operator, and thus greater comfort and security for the operator. The backrest extends from a base plate that is removably secured to the seat immediately behind the operator by a pair of adjustable lateral straps that hook beneath the lower edges of the seat structure. The bottom surface of the base plate is preferably coated or provided with a material having a high coefficient of friction, e.g., a soft plastic, Neoprene®, etc., to reduce or prevent slippage. This attachment system does not require any modification to the motorcycle, and thus does not reduce the value of the motorcycle due to alterations or modifications. Laterally extending support for the straps is provided by laterally telescoping brackets that extend from the plate as required for different seat widths. 
         [0010]    A telescoping seatback support strut is pivotally attached to the forward edge or end of the base plate. The strut extension may be adjusted as desired by the cyclist to position the seatback at the height desired. An adjustable stop is provided immediately behind the strut, allowing the fore and aft angle or rake of the strut, and therefore the seatback as well, to be adjusted as desired. The strut is free to fold forward to facilitate mounting and dismounting of the operator from the motorcycle. The seatback is pivotally attached to the upper or distal end of the strut, and automatically adjusts to provide optimum contact and support for the lower back of the cyclist. 
         [0011]    These and other features of the present invention will become readily apparent upon further review of the following specification and drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]      FIG. 1  is an environmental, perspective view of a backrest for motorcyclists according to the present invention, showing its removable attachment to a motorcycle seat. 
           [0013]      FIG. 2  is a left side elevation view of an alternative embodiment of a backrest for motorcyclists according to the present invention, showing the various angular and height adjustments provided by the backrest. 
           [0014]      FIG. 3  is a perspective view of a single attachment strap bracket assembly for a backrest for motorcyclists according to the present invention, with a single adjustable strap installed thereon. 
           [0015]      FIG. 4  is a perspective view of an alternative embodiment of a single attachment strap bracket assembly or a backrest for motorcyclists according to the present invention, having a separate adjustable attachment strap at each end thereof. 
           [0016]      FIG. 5  is an exploded rear perspective view of an alternative embodiment of a backrest for motorcyclists according to the present invention, illustrating its components and their relationship. 
           [0017]      FIG. 6  is a rear perspective view of the backrest of  FIG. 5 , illustrating the assembly of the components and the lateral adjustability of the strap support members. 
           [0018]      FIG. 7  is a rear perspective view of the backrest of  FIGS. 5 and 6 , illustrating two alternative attachment strap configurations. 
           [0019]      FIG. 8  is an exploded partial perspective view of the backrest of  FIG. 5 , showing the lower end of the seatback support strut and the latch assembly therefor. 
           [0020]      FIG. 9  is a right side elevation view in section through the base plate of the backrest of  FIGS. 5 through 8 , showing operation of the seatback support strut latch mechanism. 
       
    
    
       [0021]    Similar reference characters denote corresponding features consistently throughout the attached drawings. 
       DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0022]    The backrest for motorcyclists provides a backrest removably attachable to the seat structure of the motorcycle and extending behind the cyclist or operator. The backrest requires no modification of the motorcycle, and may be installed or removed in only a minute or two. 
         [0023]      FIG. 1  of the drawings provides an environmental perspective view of a first embodiment of the backrest  10 , shown installed upon the seat S of a motorcycle. The backrest  10  includes a rigid, elongate base plate  12  of metal or a strong and dense plastic material, with the plate  12  having a left edge  14 , an opposite right edge  16 , a forward edge or end  18 , and a rearward edge or end  20 . An alternative embodiment of the backrest  110  having a thicker base plate  112  is illustrated in the left side elevation view of  FIG. 2  and discussed further below, with the primary difference between the two embodiments being the construction and thickness of the base plate. 
         [0024]    A seatback support strut extends from the forward edge  18  of the base plate  12 . The attachment end  22  of the strut is pivotally attached to the forward edge  18  of the base plate  12  by a hinge pintle  24  extending laterally across the forward edge  18  of the base plate  12 . The seatback support strut actually comprises a base plate attachment portion  26 . The attachment end  22  of the strut is pivotally attached to the pintle  24 , and a seatback attachment portion  28  telescopically extends from the base plate attachment portion  26 . The two telescoping portions  26  and  28  may comprise mating channels, tubular members, or other configurations, wherein the smaller diameter member is retained by and telescopes from the larger diameter member. The two telescoping portions  26  and  28  allow the backrest  30  to be adjusted in height to provide optimum support for the cyclist C, as shown in broken lines in  FIG. 1 . A manually adjustable lock screw  32  extends through a slot in the rearward wall of the outermost of the two telescoping strut portions  26  and  28 , and threads into a passage in the rearward wall of the other strut member. The screw  32  may be threadably locked in place to secure the positions of the two strut portions  26  and  28  relative to one another, thereby locking the height of the backrest  30 . 
         [0025]    The backrest  30  preferably includes a forward cushion or pad. The backrest  30  is pivotally secured to the distal end  34  of the seatback attachment portion  28  of the strut by a bracket having a laterally disposed pivot pin or bolt  36  therethrough. The backrest  30  is free to pivot upwardly and downwardly about the pin or bolt  36  to the limits of the structure to which it is attached, automatically conforming to an optimal fit against the back of the cyclist using the backrest assembly  10 . 
         [0026]    The seatback support strut is free to hinge, pivot, or fold forward by its attachment to the support strut hinge pintle  24  to rest upon the forward portion of the motorcycle seat S when not in use, or to allow the cyclist to more readily swing his or her leg over the seat when mounting or dismounting from the motorcycle. However, a stop  38  extends upwardly from the forward portion of the base plate  12  to limit the rearward pivotal travel of the support strut. Adjustment to this rearward limit is provided by a manually adjustable screw  40  extending through the stop. The forward end of the screw  40  bears against the back of the base plate attachment portion  26  of the seatback support strut. The screw  40  may be threadably advanced or retracted through the stop  38  to adjust the position of its forward end, thereby adjusting the rearward limit of travel for the strut assembly and its backrest  30 . 
         [0027]    The removable backrest attaches to the seat S by means of its forward and rearward attachment strap assemblies  42  and  44 , respectively. These two attachment strap assemblies  42  and  44  are preferably identical to one another. One such strap assembly is shown in detail in  FIG. 3  of the drawings. An alternative embodiment of the attachment strap assembly is shown in  FIG. 4  and discussed further below. 
         [0028]    Each of the identical forward and rearward attachment strap assemblies  42 ,  44 , shown particularly in  FIG. 3  of the drawings, includes a strap bracket assembly comprising two substantially identical, rigid, laterally opposed overlapping strap support members, including a left member  46   a  and a right member  46   b , as shown in  FIG. 3 . These two strap support members are adjustably extendible relative to the base plate  12  and motorcycle seat S to adjust the spacing of the attachment straps (discussed further below) for different widths of motorcycle seats. 
         [0029]    Each strap support member  46   a ,  46   b  is provided with opposite outwardly and upwardly angled flanges along their elongate edges. One of the support members, e.g., left member  46   a , nests within the other support member, e.g.,  46   b , by means of their mating flanges. Each of the two strap support members  46   a ,  46   b  is provided with an elongate, longitudinal (relative to the elongate major dimensions of the support members) adjustment slot  48  extending along the center thereof, allowing the strap support members  46   a ,  46   b  to slide laterally relative to one another and to be adjusted laterally relative to the base plate  12  about a threaded member  50  extending upwardly from the base plate  12 . The threaded members  50  may comprise bolts threaded into cooperating passages into or through the base plate, as shown with the alternative base plate  112  of  FIG. 2 , or may comprise a threaded stud rigidly extending from the base plate, the slots of the strap bracket members  46   a  and  46   b  passing thereover and being clamped immovably to the underlying base plate by a cooperating nut or the like. 
         [0030]    Various attachment strap configurations may be provided, as noted further above.  FIGS. 1 and 2  generally illustrate a single strap configuration, with  FIG. 3  illustrating such a single strap configuration in detail for each of the two attachment strap assemblies  42  and  44 . The single strap  52  shown in  FIG. 3  has a first end  54  permanently attached to an adjustment buckle  56 , and an opposite second end  58 . The strap  52  extends from the buckle  56 , downwardly to a seat base attachment portion, passing through the eye or slot of a first seat base hook  58   a . The strap  52  then extends upwardly to pass through a slot  60   a  across the outboard end of the first strap bracket member  46   a , thence over the tops of the two strap bracket members  46   a  and  46   b , and downwardly through the slot  60   b  in the second strap bracket member  46   b . The strap  52  then passes through the eye of a second seat base hook  58   b , and then continues upwardly over the underlying strap portion to pass through the buckle  56 . The upper surface of this portion of the strap  52 , i.e., the top portion, may be provided with some form of attachment means  62   a , e.g., either the hook or the loop portion of hook and loop fabric fastener material. The surface of the second end  58  extending from the buckle  56  is provided with mating fastening material  62   b . Thus, the strap  52  may be secured tightly across the two strap bracket members  46   a  and  46   b  once the two seat base hooks  58   a  and  58   b  have been hooked to the seat base structure underlying the motorcycle seat S. The two hooks  58   a ,  58   b  are preferably coated with a relatively soft and/or resilient material to avoid marring the underlying seat support structure of the motorcycle. 
         [0031]      FIG. 4  illustrates an alternative embodiment of the bracket  46   a ,  46   b  and strap attachment assembly. The two strap bracket members  46   a  and  46   b  of the seat attachment embodiment of  FIG. 4  are identical to the members  46   a  and  46   b  shown in other drawings discussed further above. However, each strap bracket member  46   a  and  46   b  has a separate strap  64   a  and  64   b , respectively, in the embodiment of  FIG. 4 . Each strap  64   a  and  64   b  has a first end  66   a  and  66   b  having a buckle  56   a  and  56   b  permanently attached thereto. The two buckles  56   a ,  56   b  are substantially identical to the single buckle  56  of the single strap attachment embodiment of  FIG. 3 . Each of the straps extends from its buckle through the slot  60   a  or  60   b  of its respective strap bracket member  46   a  or  46   b , thence downward to pass through the slot or eye of its respective seat base hook  58   a  or  58   b , and back through the respective buckle  56   a  or  56   b . The second end  68   a  and  68   b  of each strap doubles back to attach to the adjacent strap portion by means of mating hook and loop fastener material  62   a  and  62   b  in the manner used to secure the single strap  52  to itself, as shown in  FIG. 3 . 
         [0032]    The backrest for motorcyclists  10  or  110  is used by initially placing the device atop the seat S of the motorcycle and positioning it as desired, e.g., as shown in  FIG. 1  of the drawings. The forward and rearward pairs of strap bracket members  46   a  and  46   b  are adjusted to the desired width in accordance with the width of the motorcycle seat S by loosening the threaded fastener or member  50  passing through the two bracket members  46   a ,  46   b , and sliding the two members inwardly or outwardly relative to one another until the desired span is achieved. The fastener  50  is then tightened to lock this span adjustment. 
         [0033]    The strap  52  ( FIGS. 1 through 3 ) or straps  64   a  and  64   b  ( FIG. 4 ) may then be adjusted as desired. The strap or straps is/are cinched up to some degree in order to remove excessive slack, and the seat base hooks  58   a ,  58   b  are hooked under the edges of the seat support pan or structure. The strap or straps  52  or  64   a  and  64   b  are then tightened and secured as explained further above to complete the installation of the backrest  10  or  100  atop the motorcycle seat S. Additional security for the backrest  10  or  100  may be provided by applying a coating  70  having a high coefficient of friction, e.g., Neoprene® or other suitable material, to the underlying seat contact surface  72  of the base plate  12  or  112 , as shown on the underside of the base plate  112  of  FIG. 2 . At this point, the height and angle of the seatback  30  may be adjusted as desired, and the backrest is ready for use. 
         [0034]    The adjustable strut is folded forwardly to place the seatback  30  against the forward portion of the motorcycle seat S to facilitate mounting the motorcycle, and then extended back to its operational position to allow the motorcyclist to place his or her back against the seatback  30  for support while riding. Removal of the device is accomplished essentially by reversing the steps described above. The motorcycle remains unmodified and undamaged throughout the installation, use, and removal of the backrest  10  or  110 . 
         [0035]      FIGS. 5 through 9  of the drawings illustrate an additional embodiment of the backrest for motorcyclists, designated as backrest  210 . The backrest  210  includes a rigid, elongate base plate  212  of metal or a strong and dense plastic material, with the plate  212  having a left edge  214 , an opposite right edge  216 , a forward edge or end  218 , and a rearward edge or end  220 . 
         [0036]    A seatback support strut extends from the forward edge  218  of the base plate  212 . The attachment end  222  of the strut is pivotally attached to the forward edge  218  of the base plate  212  by a pair of lugs or bosses  224  extending laterally along the forward edge  218  of the base plate  212 , with a lateral bolt, pin or pintle  225  extending through the lugs or bosses  224  and through passages in the attachment end  222  of the strut. The seatback support strut actually comprises a base plate attachment portion  226 . A seatback attachment portion  228  telescopically extends from the base plate attachment portion  226 . The two telescoping portions  226  and  228  may comprise mating channels, tubular members, or other configurations, wherein the smaller diameter member is retained by and telescopes from the larger diameter member. The two telescoping portions  226  and  228  allow the backrest  230  to be adjusted in height to provide optimum support for the cyclist C. A manually adjustable lock screw  232  extends through a slot in the rearward wall of the outermost of the two telescoping strut portions  226  and  228 , and threads into a passage in the rearward wall of the other strut member. The screw  232  may be threadably locked in place to secure the positions of the two strut portions  226  and  228  relative to one another, thereby locking the height of the backrest  230 . 
         [0037]    The backrest  230  preferably includes a forward cushion or pad. The backrest  230  is pivotally secured to the distal end  234  of the seatback attachment portion  228  of the strut by a bracket having a laterally disposed pivot pin or bolt  236  therethrough. The backrest  230  is free to pivot upwardly and downwardly about the pin or bolt  236  to the limits of the structure to which it is attached, automatically conforming to an optimal fit against the back of the cyclist using the backrest assembly  210 . 
         [0038]    The seatback support strut is free to hinge, pivot, or fold forward by its attachment to the support strut hinge pintle  224  to rest upon the forward portion of the motorcycle seat when not in use, or to allow the cyclist to more readily swing his or her leg over the seat when mounting or dismounting from the motorcycle. However, a stop  238  extends upwardly from the forward portion of the base plate  212  to limit the rearward pivotal travel of the support strut. Adjustment to this rearward limit is provided by a manually adjustable screw  240  extending through the stop. The forward end of the screw  240  bears against the back of the base plate attachment portion  226  of the seatback support strut. The screw  240  may be threadably advanced or retracted through the stop  238  to adjust the position of its forward end, thereby adjusting the rearward limit of travel for the strut assembly and its backrest  230 . 
         [0039]    The backrest  210  of  FIGS. 5 through 9  includes an additional feature not found in the backrest  10  of  FIGS. 1 through 4 . The backrest  210  includes a latch mechanism to secure the backrest support strut assembly  226 ,  228  in its upright position until the latch is released. This latch mechanism is shown in detail in  FIGS. 8 and 9  of the drawings. The lower or attachment end  222  includes a rearwardly extending tab or catch  280  that selectively engages a spring-loaded latch plate  282 . The latch plate  282  is pivotally secured between the two strut attachment lugs or bosses  224  by a lateral bolt or pin  284 , installed through one of the walls of the backrest strut stop  238 . The latch plate  282  includes a lower edge  286  that selectively engages the tab or catch  280  of the lower end  222  of the base plate attachment portion  226  of the seatback support strut assembly. A spring  288  is captured between a downwardly depending end and tab  290  of the latch plate  282  and a spring seat  292  formed in the lower end of the backrest strut stop  238 , with the spring  288  urging the lower portion of the latch plate  282  and its lower edge  286  forwardly to engage the catch or tab  280  of the lower portion  286  of the seatback support strut. 
         [0040]    A thumb or finger actuation tab  294  extends forwardly from the latch plate  282 , for releasing the latch assembly to allow the seatback support strut to fold forwardly as shown in broken lines in  FIG. 9 . A user of the device may press downwardly and rearwardly on the actuation tab  294  to push the lower edge  286  of the latch plate  282  rearwardly against the pressure of the spring  288 , thereby allowing the lower edge  286  to clear the catch or tab  280  of the seatback support strut to allow the strut to fold forwardly. The rounded lower and rearward edge of the catch or tab  280  automatically pushes the latch plate  282  rearwardly when the seatback support strut is raised, with the latch plate  282  springing forward to capture the catch or tab  280  of the seatback support strut when the strut is raised completely. 
         [0041]    The removable backrest  210  attaches to the motorcycle seat by means of its first and second attachment strap assemblies  242   a  and  242   b , respectively, with the complete assemblies (with straps) being shown in  FIG. 7 . These two attachment strap assemblies  242   a ,  242   b  are preferably identical to one another, but are reversed to extend to the left or right side of the seat. 
         [0042]    Each of the identical first and second attachment strap assemblies  242   a ,  242   b  includes a strap bracket, respectively  244   a  and  244   b . Each of the strap brackets  244   a ,  244   b  comprises a strap support member, respectively  246   a  and  246   b , having a series of laterally extending (relative to the orientation of the base plate  212 ) bracket attachment arms, respectively  246   a ,  246   b , and  246   c  for each bracket. The three attachment arms  246   a  through  246   c  of each bracket define two elongate slots, respectively  249   a  and  249   b  for each bracket, therebetween. 
         [0043]    A plurality of raised guides may be provided on the top surface of the base plate  212 , with the bracket attachment arms  246   a  through  246   c  of each bracket  244   a ,  244   b  fitting between corresponding guides to secure the brackets longitudinally with respect to the base plate. A series of threaded members, e.g., bolts  250 , threaded studs, etc., are installed in corresponding threaded passages in certain of the guides, to extend upwardly from the base plate  212 . As the guides are located between the bracket arms  246   a  through  246   c , it will be seen that the bolts or fasteners  250  pass between the arms and through the corresponding slots  249   a ,  249   b  defined by the arms. Large washers  251  or the like are captured by the bolts or fasteners  250 , and extend over the arms  246   a  through  246   c  to secure the arms, and thus the strap brackets  244   a  and  244   b , immovably to the base plate  212  as desired. The motorcyclist need only loosen the fasteners  250  to loosen the grip of the washers  251  on the arms  246   a  through  246   c , thereby allowing the strap brackets  244   a  and  244   b  to be repositioned laterally (as shown by the broken line positions in  FIG. 6 ) to adjust for the width of the motorcycle seat to which the device is installed. 
         [0044]    Various attachment strap configurations may be provided, as noted further above.  FIG. 7  illustrates two such strap configurations, with it being understood that these two configurations are exemplary to show two alternative arrangements. Both would not likely be installed on the same attachment strap assemblies as illustrated, although such a strap arrangement is feasible and may be selected by the user of the mechanism if so desired. 
         [0045]    The strap assembly shown attached to the forward portions of the two attachment strap assemblies  242   a ,  242   b  in  FIG. 7  comprises a first strap and a second strap, respectively  252  and  254 , joined at an adjustment buckle  256 . The first strap  252  has a first end permanently attached to an adjustment buckle  256 , and an opposite second end  258 . The strap  252  extends from the buckle  256 , across and downwardly over the outer side member of the first strap bracket  244   a  and through a slot in the first or left side seat base hook  258   a . The second end  258  of the first strap  252  terminates in a loop secured about the forward end of the side member of the first strap bracket  244   a.    
         [0046]    The second strap  254  is connected to the first strap  252  through the buckle  256 , with the two straps  252 ,  254  extending laterally across the two strap brackets  244   a  and  244   b . The second strap  254  extends downwardly over the outer member of the second strap bracket  244   b  and through the slot in the second or right side seat base hook  258   b , and back up to terminate in a second end portion  260  comprising a loop secured about the forward end of the side member of the second strap bracket  244   b . The two hooks  258   a ,  258   b  are preferably coated with a relatively soft and/or resilient material to avoid marring the underlying seat support structure of the motorcycle. 
         [0047]      FIG. 7  also illustrates another alternative strap embodiment comprising separate straps  264   a  and  264   b , respectively. Each strap  264   a  and  264   b  has a first end  266   a  and  266   b  having a buckle  256   a  and  256   b  permanently attached thereto. The two buckles  256   a ,  256   b  are substantially identical to the single buckle  256  of the embodiment of the two straps  252  and  254  shown attached to the forward portions of the two attachment strap assemblies  242   a  and  242   b . Each of the straps  264   a ,  264   b  extends from its buckle to pass over the outer member of its respective strap bracket  244   a ,  244   b , thence downward to pass through the slot or eye of its respective seat base hook  258   a  or  258   b , and back through the respective buckle  256   a  or  256   b . In this configuration, the separate and independent straps with their respective buckles allow each side to be adjusted independently of the other. 
         [0048]    The backrest for motorcyclists  210  is used in much the same manner as the backrest  10  and  110  of  FIGS. 1 through 4 , discussed further above. The backrest  210  is initially placed atop the seat of the motorcycle and positioned as desired, e.g., as shown in  FIG. 1  of the drawings. The forward and rearward pairs of strap bracket members  246   a  and  246   b  are adjusted to the desired width in accordance with the width of the motorcycle seat S by loosening the threaded fasteners or members  250  passing through the slots  249   a  and  249   b  between the arms  248   a  through  248   c  of the two bracket members  246   a ,  246   b , and sliding the two members inwardly or outwardly relative to one another until the desired span is achieved. The fasteners  250  are then tightened to lock this span adjustment. 
         [0049]    The straps  252  and  254  and/or straps  264   a  and  264   b  (shown in  FIG. 7 ) may then be adjusted as desired. The straps are cinched up to some degree in order to remove excessive slack, and the seat base hooks  258   a ,  258   b  are hooked under the edges of the seat support pan or structure. The straps  252 ,  254  or  264   a  and  264   b  are then tightened and secured as explained further above to complete the installation of the backrest  210  atop the motorcycle seat. Additional security for the backrest  210  may be provided by applying a coating  270  having a high coefficient of friction, e.g., Neoprene® or other suitable material, to the underlying seat contact surface  272  of the base plate  212 , as shown particularly in  FIGS. 8 and 9 . At this point, the height and angle of the seatback  230  may be adjusted as desired, and the backrest is ready for use. 
         [0050]    The adjustable strut is folded forwardly to place the seatback  230  against the forward portion of the motorcycle seat to facilitate mounting the motorcycle, and then extended back to its operational position to allow the motorcyclist to place his or her back against the seatback  230  for support while riding. The latch mechanism illustrated in  FIGS. 8 and 9  secures the strut and its seatback  230  in an upright orientation, once the strut and seatback have been raised. The relatively wide and rigid structure of the assembled strap brackets  244   a ,  244   b  enable the device to be used as a luggage carrier, as well. Removal of the device is accomplished essentially by reversing the steps described above. The motorcycle remains unmodified and undamaged throughout the installation, use, and removal of the backrest  210 . 
         [0051]    It is to be understood that the present invention is not limited to the embodiments described above, but encompasses any and all embodiments within the scope of the following claims.