Abstract:
A vehicle spring assembly includes a cylindrical hollow cover defining an opening at each end. A spring is disposed within the cover, and fittings disposed at each end of the cover are configured to contain the spring within the cover. Each fitting defines an aperture. An elongated damper extends in part within the spring along a direction of elongation. The damper includes a pair of opposing end sections each extending through and projecting from the aperture of one of the fittings. Each end section defines a groove. One end section is connectable to a vehicle tailgate, and the other end section is connectable to a vehicle body. Fasteners securing the fittings to the cover are disposed adjacent the grooves defined in the damper end sections.

Description:
BACKGROUND 
       [0001]    The disclosed subject matter is directed to a vehicle door strut apparatus, and methods of use and manufacture thereof. More particularly, the disclosed subject matter is directed to methods and apparatus for enhancing failsafe capabilities in vehicle assembly, and facilitating controlled failure and breaking of vehicle door strut apparatuses within vehicles. 
         [0002]    Door and panel struts can be provided for connecting doors and panels to a vehicle body to facilitate opening and closing of the doors and panels, such as struts connecting passengers doors, tailgates and trunks, hoods/bonnets, storage compartments, aerodynamic panels, etc. Some related art struts include springs that serve to counteract weight of the doors and/or panels to which the struts are connected to reduce an amount of effort needed to move and reposition the doors and panels. Reducing the amount of effort needed to move doors and panels may be beneficial for various reasons, such as to facilitate easier movement of the doors and panels which would otherwise subject vehicle operators to unnecessary physical strains or require enhanced door and panel motors having increased cost, size, complexity, etc. 
       SUMMARY 
       [0003]    Some types of vehicles, such as passenger vehicles, include strut assemblies having springs positioned between ends of a damper, and thus it may be beneficial to provide a tube between the damper ends for containing the spring therein. For example, these containment tubes can include caps fastened to both ends of the tubes to enclose the spring within the tube. 
         [0004]    In some such structures, the spring assembly may be configured such that excessive transverse and lateral forces on the assembly can cause structural failures at various portions of the assembly. Thus, portions of the assembly within which the spring is contained may be caused to break by the excessive forces. This structure may be subject to the disadvantage that containment of the spring within the assembly may be compromised should the assembly break at a portion containing the spring. In other words, the spring may be released from the assembly during structural failure, which poses both a safety risk and can lead to scattering of assembly parts, among other things. 
         [0005]    It may therefore be beneficial to provide methods and apparatus that facilitate controlled failure of the struts at predetermined locations along the spring assembly. For example, it may be beneficial to provide a spring assembly having a spring surrounding a damper, the spring and a portion of the damper being contained within an outer tube, and the damper having grooves at portions outside the outer tube. The spring can be contained within the outer tube by end caps fastened to the damper on either side of the spring, the end caps positioned adjacent the respective grooves. The strut assembly can also include connection fittings positioned at opposing ends of the damper and spaced from the outer tube such that the grooves are located between the connection fittings and outer tube. This structure enables controlled failure of the spring assembly at predetermined locations outside the tube containing the spring and thereby impedes or prevents release of the spring from the assembly during instances of excessive forces applied to the assembly. 
         [0006]    Some of the embodiments are therefore directed to a vehicle spring assembly for use with a spindle motor that causes the vehicle spring assembly to actuate a vehicle tailgate relative to a vehicle body. The vehicle spring assembly can include a cylindrical hollow cover that extends along a direction of elongation and that defines an opening at each opposing end. A spring disposed within the cover can extend along the direction of elongation. A pair of fittings can each be disposed at one of the ends of the cover and configured to contain the spring within the cover. Each of the fittings can define an aperture. An elongated damper can extend in part within the spring along the direction of elongation. The damper can include a pair of opposing end sections that each extend through and project from the aperture of one of the fittings. Each of the end sections can define a groove. One of the end sections can be connectable to the vehicle tailgate, and the other of the end sections can be connectable to the vehicle body. Each of a pair of fasteners can secure one of the fittings to the cover, and can be disposed adjacent one of the grooves defined in the end sections of the damper. 
         [0007]    Some other embodiments are directed to spindle drive system for use with a vehicle tailgate and a vehicle body. The spindle drive system can include a vehicle spring assembly that includes a cylindrical hollow cover that extends along a direction of elongation and that defines an opening at each opposing end. A spring disposed within the cover can extend along the direction of elongation. A pair of fittings can each be disposed at one of the ends of the cover and configured to contain the spring within the cover. Each of the fittings can define an aperture. An elongated damper can extend in part within the spring along the direction of elongation. The damper can include a pair of opposing end sections that each extend through and project from the aperture of one of the fittings. Each of the end sections can define a groove. One of the end sections can be connectable to the vehicle tailgate, and the other of the end sections can be connectable to the vehicle body. Each of a pair of fasteners can secure one of the fittings to the cover, and can be disposed adjacent one of the grooves defined in the end sections of the damper. The spindle drive system can also include a spindle motor that is connected to the vehicle spring assembly and controllable to cause the vehicle spring assembly to actuate the vehicle tailgate relative to the vehicle body. 
         [0008]    Still other embodiments are directed to a method of manufacturing a vehicle spring assembly for use with a spindle motor that causes the vehicle spring assembly to actuate a vehicle tailgate relative to a vehicle body. The method can include: forming an opening at each opposing end of a cylindrical hollow cover that extends along a direction of elongation; disposing a spring within the cover so as to extend along the direction of elongation; disposing each of a pair of fittings at one of the ends of the cover so as to contain the spring within the cover; defining an aperture in each of the fittings; disposing an elongated damper so as to extend in part within the spring along the direction of elongation, the damper including a pair of opposing end sections that each extend through and project from the aperture of one of the fittings; forming a groove in each of the end sections of the damper; connecting one of the end sections of the damper to the vehicle tailgate; connecting the other of the end sections of the damper to the vehicle body; securing the pair of fittings to the cover with a pair of fasteners; and disposing each of the fasteners adjacent one of the grooves defined in the end sections of the damper. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    The disclosed subject matter of the present application will now be described in more detail with reference to exemplary embodiments of the apparatus and method, given by way of example, and with reference to the accompanying drawings, in which: 
           [0010]      FIG. 1  is a side view of an exemplary vehicle including a tailgate assembly in accordance with the disclosed subject matter. 
           [0011]      FIG. 2  is a partial perspective view of the exemplary tailgate assembly including strut assemblies in accordance with the disclosed subject matter. 
           [0012]      FIG. 3 . is a cross-section view of the strut assembly of  FIG. 2  including fuses at end portions of the strut assembly. 
           [0013]      FIG. 4  is an enlarged cross-section view of the fuse of  FIG. 3 . 
           [0014]      FIG. 5A  is a side view of the exemplary strut assembly as a result of a center force. 
           [0015]      FIG. 5B  is a side view of the exemplary strut assembly as a result of an end force. 
           [0016]      FIG. 5C  is a side view of the exemplary strut assembly as a result of another end force. 
       
    
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
       [0017]    A few inventive aspects of the disclosed embodiments are explained in detail below with reference to the various figures. Exemplary embodiments are described to illustrate the disclosed subject matter, not to limit its scope, which is defined by the claims. Those of ordinary skill in the art will recognize a number of equivalent variations of the various features provided in the description that follows. 
         [0018]    Various headings are provided below for convenience and clarity. However, these headings are not intended to limit the scope or content of the disclosure, and/or the scope of protection afforded the various inventive concepts disclosed herein. 
         [0019]    I. Overall Vehicle 
         [0020]      FIG. 1  is a side view of an exemplary vehicle  10  including a tailgate assembly  30  in accordance with the disclosed subject matter. The vehicle  10  shown in  FIG. 1  is primarily for use on paved roadways, and can be referred to as a passenger vehicle. The vehicle  10  may also be for use on unpaved roadways consisting of gravel, dirt, sand, etc. 
         [0021]    However, the disclosed tailgate assembly  30  can be used with any vehicle that is configured for travel along any one or combination of improved, unimproved, and unmarked roadways and paths consisting of gravel, dirt, sand, etc. For example, embodiments are intended to include or otherwise cover any type of automobile, including passenger car, minivan, truck, etc. In fact, embodiments are intended to include or otherwise cover configurations of the tailgate assembly  30  for use in any other type of vehicle, such as an aircraft, boat, ship, train, spacecraft, etc. Some other embodiments can be used in non-vehicular applications, such as for amusement park rides, elevators, or any other situation where access to an enclosed space can be provided through opening a door assembly. 
         [0022]    The vehicle  10  can include a body  12 , a pair of front wheels  14  (the right-side front wheel is obstructed from view), a pair of rear wheels  16  (the right-side rear wheel is obstructed from view), a pair of front door assemblies  24  (the right-side front door assembly is obstructed from view), a pair of rear door assemblies  26  (the right-side rear door assembly is obstructed from view), the tailgate assembly  30 , a frame assembly, and a powertrain. The frame assembly and the powertrain are omitted from  FIG. 1  for simplicity and clarity of the drawings. 
         [0023]    II. Tailgate Assembly 
         [0024]      FIG. 2  is a partial perspective view of the exemplary tailgate assembly  30  including strut assemblies  40  in accordance with the disclosed subject matter. The tailgate assembly  30  shown in  FIG. 2  can be hingedly connected to the body  12  proximate a roofline at a rear of the vehicle  10 . The tailgate assembly  30  may therefore move between opened and closed positions by rotating upward and downward via hinges. 
         [0025]    The tailgate assembly  30  can include a door frame  32  defining a window opening  34 . The door frame  32  has a hinge side  36  at an upper portion and a latch side  38  at a lower portion, the hinge side  36  being configured to connect to the roofline of the body  12  such that the door frame  32  rotates about the hinge side  36  to move between the opened and closed positions. Furthermore, the latch side  38  rotates with the door frame  32  to latch and unlatch with a lower portion of the body  12  proximate a rear bumper as the door frame rotates between opened and closed positions. The tailgate assembly  30  can alternatively be configured such that the door frame  32  is hingedly connected to a side portion of the body  12  at a rear of the vehicle  10 . In such embodiments, the door frame  32  can rotate about the side portion of the body  12  and latch and unlatch with another side portion of the body  12 . In yet further embodiments, the tailgate assembly  30  can be configured such that the door frame  32  is hingedly connected to the lower portion of the body  12 . The door frame  32  can thereby rotate about the lower portion of the body  12  and latch and unlatch the portion of the body  12  proximate the roofline, or alternatively with another tailgate assembly in a clamshell manner. 
         [0026]    The tailgate assembly  30  can include a pair of strut assemblies  40  configured for actuation of the door frame  32  about the hinge side  36  between the opened and closed positions. The strut assemblies  40  are connected to the body  12  proximate the hinges at the roofline, and the door frame  32  at the hinge side  36 . 
         [0027]    III. Strut Assembly 
         [0028]    The pair of strut assemblies  40  can be configured to open and close the door frame  32  about the hinges at the hinge side  36 , and can each include a motor assembly  50  and a spring assembly  60 . The motor assemblies  50  can be configured to actuate the door frame  32  between the opened and closed positions via the respective spring assemblies  60 . In the present embodiment, the strut assemblies  40  can include spindle drive systems for powered extensions and retraction of the door frame  32 . The spindle drive systems can be disposed within the roof of the vehicle  10  to yield increased package space and utility over spindle drive systems positioned within gutters of the vehicle  10 . Specifically, the spindle drive systems may be partially positioned within and reinforced by roof rails of the vehicle  10 . However, other drive systems may be incorporated within the strut assemblies  40  to provide power opening and closing functionality for the tailgate assembly  30 . 
         [0029]      FIG. 3 . shows a cross-section view of the strut assembly  60  of  FIG. 2  including fuses  76  at end portions of the strut assembly  60 . In addition to fuses  76  at end portions, the strut assembly  60  can include a spring  62  configured to surround a damper  64  and disposed within a cover  72 . A spring guide  66  can be disposed between the damper  64  and the spring  62 , the spring guide  66  being configured approximately as a cylindrical shell around the damper  64 . The spring guide  66  may serve as a buffer and guide movement of the spring  62  both around the damper  64  and within the cover  72 . Particularly, the spring guide  66  can guard against buckling of the spring  62  inwards towards the damper  64 . As will be discussed in further detail below, the fuses  76  can be disposed at opposite ends of the damper  64  such that the spring  62  surrounds the damper  64  between the fuses  76 . The fuses  76  are configured as parts positioned between fasteners and mount points on either end portion of the spring assembly  60 . The spring  62  of the spring assembly  60  is configured to counteract weight of the tailgate assembly  30 , particularly the door frame  32 , during operation of the tailgate assembly  30  so that the respective motor assembly  50  may adequately power the tailgate assembly  30  to transition between the opened and closed positions. 
         [0030]    The damper  64  of the present embodiment can extend through a center of the spring  62  along a longitudinal direction so that ends of the damper  64  extend beyond corresponding ends of the spring  62 . Ends of the damper  64  can be threaded so as to be configured to receive a threaded base retainer  68  and a threaded tip retainer  70 , respectively, the base retainer  68  and the tip retainer  70  configured to abut and retain the spring  62  between the ends of the damper  64  and within the cover  72 . The base retainer  68  and the tip retainer  70  can be secured onto respective ends of the damper  64  by threaded nuts  74  screwed onto the threaded ends adjacent the base and tip retainers  68 ,  70 . The nuts  74  may be accompanied by respective washers inserted onto respective portions of the damper  64  so as to be disposed adjacent the nuts  74  to provide additional support for securing the base and tip retainers  68 ,  70 . Furthermore, the base retainer  68  and the tip retainer  70  maintain the spring  62  within the cover  72 , the cover  72  being configured as an outer tube to surround an exterior of the spring  62 . The base retainer  68  and the tip retainer  70  can alternatively be connected to the damper  64  to secure the spring  62  by locking or another appropriate method other than being screwed along threads, or by threaded nuts. 
         [0031]    As shown in more detail in  FIG. 4 , the spring assembly  60  can include fuses  76  disposed at the end portions of the damper  64 . The fuse  76  can be configured as a groove encircling a portion of the damper  64  adjacent the nut  74  such that the nut  74  is disposed between the fuse  76  and the tip retainer  70 . The fuse  76  can be a mechanical fuse configured as a breaking point of the damper  64  such that a certain amount of force acting on the damper  64  may cause breakage of the damper  64  at the fuse  76 . The configuration of the fuse  76  described above disposed proximate the tip retainer  70  may be applicable to the other fuse  76  disposed proximate the base retainer  68  at the opposite end of the damper  64 . The spring assembly  60  can therefore be configured to have the pair of fuses  76  disposed at the ends of the damper  64  such that either fuse  76  may break to relieve stress on the spring assembly  60 , as will be described below. 
         [0032]    The spring assembly  60  can also include end fittings  82  and rotation fittings  78  disposed at the corresponding end portions of the damper  64 . For example, the end portion of the damper  64  proximate the tip retainer  70  can include the end fitting  82  interconnected with the rotation fitting  78  so that the fittings  82 ,  78  are adjacent the fuse  76 . Similarly, the opposite end portion of the damper  64  proximate the base retainer  68  can also include the other end fitting  82  interconnected with the rotation fitting  78  so that the fittings  82 ,  78  are adjacent the other fuse  76 . The end fittings  82  are configured as connection components serving as mount points for coupling the spring assemblies  60  to both the roofline of the body  12  and the door frame  32 . The end fittings  82  may therefore be formed as ball sockets to act as ball joints with complementary protrusions on both the body  12  and the door frame  32 . A clip  80  can be included with each of the end fittings  82  to enhance connection between the end fitting  82  and the complementary protrusion received therein. This configuration permits the spring assemblies  60  to transition between various angles and positions as the door frame  32  rotations about the hinges between the opened and closed positions. As the end fittings  82  ensure retention of complementary connection structures on both the body  12  and the door frame  32 , the rotation fittings  78  are configured to limit rotation of the end fittings  82  about the damper  64  to which they are attached. By limiting rotation of the end fittings  82 , the rotation fittings  78  facilitate actuation of the spring assemblies  60  with a prescribed range of motion corresponding to the opened and closed positions of the door frame  32 . 
         [0033]    As described above, the fuse  76  can be configured as a groove at each end of the damper  64  disposed between the adjacent nuts  74  and end fittings  82 . Specifically, the ends of the damper  64  include shaft-like portions extending along the direction of elongation, the shaft-like portions being threaded so as to accommodate the nuts  74  and the end fittings  82 . The shaft-like portions may therefore be cylindrical with circular cross-sections. At the fuses  76  of each end, a diameter of the shaft-like portion is less than that of the shaft-like portion adjacent the fuses  76 . The decreased diameter results in decreased structural rigidity of the shaft-like portion at the fuses  76 , thereby biasing the spring assembly  60  to fail and break at the fuses  76  pending threshold force(s) acting on the spring assembly  60 . The fuses  76  therefore preserve retention of the spring  62  within the spring assembly  60  via the base and tip retainers  68 ,  70  in conjunction with the corresponding nuts  74 . The fuses  76  can alternatively be disposed adjacent welded flanges to retain the spring  62  within the spring assembly  60 , rather than nuts  74 . 
         [0034]    By maintaining the base and tip retainers  68 ,  70  retaining the spring  62  within the spring assembly  60 , the configuration of the nuts  74  and the fuses  76  impede the spring  60  such that the spring  60  may not be expelled from the spring assembly  60  by virtue of the spring bias force. Due to containment of the spring  62  within the spring assembly  60 , and specifically on either end of the spring  62  by the base and tip retainers  68 ,  70 , the spring  62  is thereby biased within the spring assembly  60 . Thus, as discussed above, movement of either the base retainer  68  or the tip retainer  70  may result in expulsion of the spring  62  from the spring assembly  60 . As will be described in detail below, the fuses  76  disposed outside of the nuts  74  encourage the spring assembly  60  to fail at the fuses  76  of the damper  64  as a result of threshold force(s) acting on the spring assembly  60  to safeguard the retention of the spring  62  by the base and tip retainers  68 ,  70 . 
         [0035]    IV. External Force Management 
         [0036]      FIGS. 5A-C  are side views of the exemplary strut assembly  40  as a result of external forces F acting thereon. External force management during a predetermined transverse loading such as shear or bending applied to the tailgate assembly  30  that can be provided by the strut assemblies  40  is described with reference to  FIGS. 5A-C .  FIGS. 5A-C  depict portions of the strut assemblies  40 , notably the spring assemblies  60 , prior to and following an external force F acting thereon. An external force F may act on directly or indirectly on the spring assemblies  60  during assembly of the tailgate assembly  30 , and/or installation of the tailgate assembly  30  onto the vehicle  10 .  FIG. 5A  depicts a possible orientation of the spring assembly  60  prior to and following an external force F acting on a central portion of the spring assembly  60 , while  FIGS. 5B-C  depict possible orientations of the spring assembly  60  prior to and following an external force F acting on end portions of the spring assembly  60 . 
         [0037]    The spring assembly  60  shown in  FIG. 5A  includes the mechanical fuse  76  formed between the nut  74  adjacent the base retainer  68  and the end fitting  82 . The fuse  76  can be configured as a failure point arranged at an uncovered and unprotected location along the shaft of the damper  64 . The above described configuration allows the fuse  76  to fail under predetermined lateral and transverse loading forces such as shear and/or bending forces applied to the tailgate assembly  30 . Transverse loading forces may occur during assembly and/or installation of the tailgate assembly  30 , and specifically the strut assemblies  40 . In the event an external force F is applied to the spring assembly  60  of the tailgate assembly  30 , one or both of the fuses  76  may be configured to break and thereby permit movement of the spring assembly  60  in response to the force F. 
         [0038]      FIG. 5A  particularly depicts the force F applied to the central portion of the spring assembly  60 , resulting in the fuse proximate the base retainer  68  breaking. As the fuse  76  breaks, the end portion of the damper  64  may move in response to the force F along a direction of the force F, as shown. A degree to which the spring assembly  60  is moved is dependent upon a magnitude of the force F, and whether the other fuse  76  proximate the tip retainer  70  is still intact. If the other fuse  76  is unbroken, the spring assembly  60  will rotate about the still attached end portion of the damper  64 , whereas if the other fuse  76  also breaks, the spring assembly  60  may move in a manner uninhibited by other structures. The movement of the spring assembly  60  depicted in  FIG. 5A  represents a possible movement direction and orientation that the spring assembly  60  may adopt as a result of the force F, however the force F may cause the spring assembly  60  to move along any direction should at least one of the fuses  76  break. Thus, as described above, the fuses  76  of the spring assembly  60 , in conjunction with the corresponding nuts  74 , preserve integrity of the spring  62  containment between the base and tip retainers  68 ,  70  and within the cover  72 . 
         [0039]    In the instance in which an external force F acts on the central portion of the spring assembly  60  as shown in  FIG. 5A , the spring assembly  60  may be configured to fail at either end such that either fuse  76  may break. Which fuse  76  breaks will be dependent upon which experiences direct or indirect force beyond a certain threshold such that the fuse  76  breaks to impede the force from increasing in magnitude on the spring assembly  60 . Therefore, despite  FIG. 5A  depicting the fuse  76  proximate the base retainer  68  breaking from an external force F applied at the central portion of the spring assembly  60 , the other fuse  76  proximate the tip retainer  70  can alternatively or additionally break as a result of an external force F applied at the central portion. 
         [0040]      FIGS. 5B-C  particularly depict forces F applied to opposing end portions of the spring assembly  60 , resulting in the respective fuse  76  nearest the force F breaking. As described above, the fuse  76  is a weakened section that is not covered by another component such as a nut, washer, sleeve, etc. and therefore is predisposed to break and fail under excessive lateral forces applied to the spring assembly  60 . These excessive forces may be present during assembly of the tailgate assembly  30 , or alternatively during installment of the tailgate assembly  30  onto the vehicle  10 . Without another component covering the weakened fuses  76  that could prevent shear or bending loads from being applied to the fuses  76 , the fuse(s)  76  proximate the force F is configured to break and allow the spring assembly  60  to disconnect from a corresponding connection component without releasing the spring  62 . For example, as shown in  FIG. 5B , the fuse  76  proximate the tip retainer  70  can break and allow the spring assembly  60  to disconnect from the respective end fitting  82  while retaining the spring  62  between the base and tip retainers  68 ,  70  and within the cover  72 . Alternatively,  FIG. 5C  depicts a situation in which the fuse  76  proximate the base retainer  68  can break and allow the spring assembly  60  to disconnect from the respective end fitting  82  while retaining the spring  62  between the base and tip retainers  68 ,  70  and within the cover  72 . In both instances, the spring assembly  60  is configured to move along the direction of the force after disconnecting from the end fitting  82 . 
         [0041]    During operation of the tailgate assembly  30 , it is possible that an external force may result in a tensile load on elements such as the strut assemblies  40 . For instances of tensile forces, the tailgate assembly  30  can include a clutch mechanism for impeding tensile overloads during operation of the tailgate assembly  30 . The tailgate assembly  30  thereby accommodates external forces during movement of the tailgate assembly  30  between the opened and closed positions via the clutch mechanism, while accommodating excessive lateral forces during assembly and installation of the tailgate assembly  30  via the fuses  76  of the spring assemblies  60 , as described above. 
         [0042]    V. Alternative Embodiments 
         [0043]    While certain embodiments of the invention are described above, and  FIGS. 1-5C  disclose the best mode for practicing the various inventive aspects, it should be understood that the invention can be embodied and configured in many different ways without departing from the spirit and scope of the invention. 
         [0044]    For example, embodiments are disclosed above in the context of the spring assemblies  60  of the tailgate assembly  30  shown in  FIGS. 2-5C . However, embodiments are intended to include or otherwise cover any type of connection member having a spring disposed therein for facilitating ease of operation of an attached door, as disclosed above. 
         [0045]    For example, exemplary embodiments are intended to include strut assemblies  40  having springs  62  contained therein for counteracting weight of the door frame  32  during operation of the tailgate assembly  30  about hinges at a rear of the body  12  of the vehicle  10 . This tailgate assembly  30  can be hingedly connected to the body  12  at a rear portion of the roofline such that the tailgate assembly  30  hinges up to open and down to close. This hinging can encompass a multitude of positions of the tailgate assembly  30  along a curved path of motion around the hinges at the roofline. In another embodiment, the tailgate assembly  30  can be hingedly connected to a lower portion of the body  12  at the rear, such as proximate a rear bumper. In another alternate embodiment, the tailgate assembly  30  can be hingedly connected to side portions of the body  12  at the rear, so that the door frame  32  extends between the roofline and the rear bumper along either the driver-side or the passenger-side of the body  12 . 
         [0046]    In fact, in some embodiments, the strut assemblies  40  of the exemplary tailgate assembly  30  can be included in front or rear side doors of a vehicle. Furthermore, panels other than doors such as a hood/bonnet of a vehicle may include the disclosed strut assemblies  40  such that the panels are oriented so as to have forces acting thereon, either during assembly or installation onto the vehicle  10 . Luggage compartments, convertible roofs, and motorized spoilers of vehicles may also be configured to incorporate the strut assemblies  40  in accordance with the disclosed subject matter. 
         [0047]    All or some of the alternative structures disclosed above with regard to the tailgate assembly  30  also apply to non-vehicular applications. The above alternative configurations of the strut assemblies  40 , and specifically the spring assemblies  60 , are merely provided for exemplary purposes, and as indicated above, embodiments are intended to cover any type of connection member having a spring disposed therein that operate or otherwise perform as disclosed above. Embodiments are also intended to include or otherwise cover any alternative or additional connection members that are structured and disposed to perform as disclosed above with regard to the spring assemblies  60 . 
         [0048]    As disclosed above, embodiments are intended to be used with any type of vehicle. The power source of the vehicle can be an internal combustion engine, an electric motor, or a hybrid of an internal combustion engine and an electric motor. The power source configured as an internal combustion engine or a hybrid power source can have the engine output axis oriented in the longitudinal direction or in the traverse direction of the vehicle. The engine can be mounted forward of the front axles, rearward of the rear axles, or intermediate the front and rear axles. 
         [0049]    The vehicle can include any type of transmission, including an automatic transmission, a manual transmission, or a semi-automatic transmission. The transmission can include an input shaft, an output shaft, and a speed ratio assembly. 
         [0050]    Embodiments are also intended to include or otherwise cover methods of using and methods of manufacturing any or all of the elements disclosed above. The methods of manufacturing include or otherwise cover processors and computer programs implemented by processors used to design various elements of the adjustable arm rest mechanism disclosed above. 
         [0051]    While the subject matter has been described in detail with reference to exemplary embodiments thereof, it will be apparent to one skilled in the art that various changes can be made, and equivalents employed, without departing from the scope of the invention. All related art references discussed in the above Background section are hereby incorporated by reference in their entirety.