Abstract:
A zip line or trolley system kit for propelling a person or an object using gravity along an extended cable line suspended between two trees or towers. The zip line system having a frame with one or more wheels, an adjustable length seat, a handle and a braking system for slowing the speed of descent of the zip line system. The trolley system having at least two wheels spaced apart at a suitable distance to increase ride smoothness and improve sliding of the zip line system along the extended cable. An actuator of the braking system allows for the rider to control of the speed of descent of the zip line system.

Description:
FIELD OF THE INVENTION 
       [0001]    The invention relates to a trolley for guiding a person or an object using gravity along an extended cable line suspended between two spaced apart objects such as trees or towers, and more specifically relates to a zip line kit or system with an easily adjustable seat and handle arrangement which in combination with a wheel and braking system for the device facilitates a safe and controllable descent along the cable line. The trolley is provided with at least two wheels spaced apart at a suitable distance to increase ride smoothness, provide sufficient space to accommodate the braking system and improve operation of the zip line system along the extended cable. 
       BACKGROUND OF THE INVENTION 
       [0002]    A zip line system is a work or recreational device which allows a user to maneuver or traverse themselves, or another person, object or load by use of a trolley along a suspended line or cable generally from a higher point of elevation to a lower point of elevation using gravity, although the trolley, person, object or load may be moved in any direction along the suspended line or cable depending on the use of different forces, arrangement of the zip line system and necessity. The line or cable can be a rope, steel cable, wire or other similar elongate support, even a rigid elongate support such as a steel or wooden beam, which can be extended between two points. The line or cable and zip line system generally permits travel of the trolley along the vector defined by the cable or line. The trolley has at least a wheel and preferably a plurality of wheels rotatably supported by the trolley which in turn support the trolley upon the line or cable. 
         [0003]    The trolley may be permanently and/or removably supported by the cable and will generally include at least a handle, sling, harness or netting affixed or suspended from the trolley to support the person, load or object. Commercial trolleys for instance for mountain climbing and eco-tourism like jungle canopy tours use a trolley to which a safety harness is secured. The safety harness is a support which is merely a set of fabric straps that are adjusted around the legs and buttocks of a person with a suspension strap that connects to the trolley or pulley system. The person is directly suspended from the trolley system and must hold onto the suspension strap as they traverse the zip line. 
         [0004]    Known zip line systems do not have a seat to comfortably support the rider during the traverse, nor an adjustment mechanism which makes the seat easily adjustable for people of different sizes. Usually the rider dangles within the harness directly from the trolley system. Known zip line systems also generally do not have any type of handle for a rider to hold directly onto the trolley while they are also supported by the adjustable seat. 
         [0005]    Additionally, known zip line systems do not have any type of braking system in the trolley itself and the user has little or no ability to slow themselves down, or even stop themselves during the traverse. In most current systems a rubber or cushioned bumper is positioned at the base of the cable to intercept and stop the trolley from sliding further down the cable. This provides little safety or control to the user and thus there exists a need for an improved zip line system, trolley and seat support for a zip line system as well as a brake safety device to slow the descent of the trolley and person, load or object traversing along the cable of the zip line system. 
       OBJECTS AND SUMMARY OF THE INVENTION 
       [0006]    The zip line system of the present invention may be offered as a completely assembled unit or a kit with various components including for example the trolley, a braking system, handle, webbing, a seat and a trolley return line. Other components of the system could include but are not limited to a safety harness, a cable as well as structural accessories, fasteners and tools such as a come-along and cable cutters which facilitate constructing and suspending the cable between two points. 
         [0007]    The zip line kit has an improved trolley system that supports at least one, and preferably two or more wheels sandwiched between two frame pieces. The frame pieces can be manufactured of aluminum or other metal, certain rigid plastics or other stiff durable materials such as carbon fiber could be used as well. The frames are affixed to one another sandwiching the wheels therebetween. The frames can be removably affixed for instance by bolts, screws or other such fastening devices. The frames can be permanently connected for instance by rivets or welding or even hingedly connected by a hinge or quick-release and fastening system which allows the frames to hinge along parallel or non-parallel planes with respect to one another. Such a hinge connection may facilitate taking the trolley on and off a cable without having to take the cable down or completely take the trolley apart. 
         [0008]    In any event the trolley is securely affixed to and supported on the cable, line, rope or wire with the cable inserted through, i.e. generally in a planar relation between the two frame pieces and below the wheels, so the wheels rest on the top of the cable and support the trolley so that it can roll efficiently along and traverse the cable. It is to be appreciated that there could be an additional wheel or wheels below the cable to facilitate maintaining the trolley tracking along the cable. 
         [0009]    A handle is secured through each of the frame pieces using cushioned grips, improving the comfort, and grip of the handle for the rider. Alternatively, a dual piece handle may be formed by engaging threadable sections which engage with one another, or which engage directly with frame pieces. The frame pieces also support fabric webbing, although a cable or rope may also be contemplated, that extends from the base of each of the frame pieces to support a seat for the zip line rider beneath the trolley. This adjustment allows the seat to be positioned at a desired distance below the handle for a rider to comfortably hold the handle essentially above their head while seated. The seat may be of aluminum, another metal or of a plastic composite with an ergonomic shape to allow for a rider to sit comfortably. 
         [0010]    It is an object of the present invention to provide a trolley for a zip line system including a braking system including a brake pad and actuator to control the amount of braking desired by the rider as the rider slides along the cable. 
         [0011]    It is another object of the present invention to provide an improved zip line system and trolley for traversing a cable with the trolley having an increased distance between each wheel to permit the trolley to more efficiently traverse the cable and permit the braking system to be located between the spaced apart wheels. 
         [0012]    It is another object of the present invention to provide a zip line system with an easily adjustable seat to more comfortably accommodate riders of different sizes. 
         [0013]    It is still another object of the present invention to secure the pulley system of the zip line apparatus within a quick release frame to allow the apparatus to be easily secured and removed from a cable, rope or wire. 
         [0014]    It is yet another object of the present invention to have a braking system which a rider activates to slow the descent of the zip line along the cable or wire. 
         [0015]    It is still yet another object of the present invention to have a braking system which a rider de-activates to slow the descent of the zip line along the cable or wire. 
         [0016]    It is a further object of the present invention that the brake pad has a lining to increase frictional resistance while reducing wear on the wire or cable. 
         [0017]    The present invention is directed to trolley for traversing a zip line system comprising a frame including at least two wheels rotatably affixed to the frame; a brake affixed to the frame for engaging an object supporting the trolley in the zip line system; a handle secured to the frame permitting a user to grasp the trolley; an adjustable seat secured to the frame; and wherein the brake is actuated by the user while grasping the handle of the trolley to control the descent of the user and the trolley along the zip line system. 
         [0018]    The present invention is also directed to a method of carrying a person or object along an extended wire comprising the steps of attaching a pulley system to a frame, the pulley system adequate to roll along the wire; attaching a braking system to the frame to control the speed of the person or object along the wire; attaching a seat using fabric webbing to the frame, the fabric webbing being adjustable to change the distance of the seat from the frame; and attaching a handle to the frame. 
         [0019]    The present invention is further directed to a kit for a zip line system comprising a frame; a pulley system; a braking system; one or more straps of fabric webbing; an adjustable seat; and a handle. 
         [0020]    These and other features, advantages and improvements according to this invention will be better understood by reference to the following detailed description and accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
         [0021]    Several embodiments of the present invention will now be described by way of example only, with reference to the accompanying drawings in which: 
           [0022]      FIG. 1  is a perspective view of an embodiment of the zip line system of the present invention; 
           [0023]      FIG. 2  is an embodiment of the zip line system kit; 
           [0024]      FIGS. 2A-2E  are views of the components of the zip line system kit of the present invention, including a frame, a handle a braking system, a seat and a suspension strap, respectively; 
           [0025]      FIG. 3A  is a perspective view of a first embodiment of the frame and brake assembly for an embodiment of the zip line system of the present invention; 
           [0026]      FIG. 3B  is an exploded view of a first embodiment of the frame and brake assembly for an embodiment of the zip line system of the present invention; 
           [0027]      FIG. 3C  is a perspective view of an embodiment of the zip line system with a first embodiment of the frame and brake assembly; 
           [0028]      FIG. 4  is an exploded view of a second embodiment of the frame and brake assembly for another embodiment of the zip line system of the present invention; 
           [0029]      FIG. 5A  is a perspective view of a second embodiment of the frame and brake assembly for another embodiment of the zip line system of the present invention; 
           [0030]      FIG. 5B  is an exploded view of a second embodiment of the frame and brake assembly for another embodiment of the zip line system of the present invention; 
           [0031]      FIG. 5C  is a perspective view of another embodiment of the zip line system with a second embodiment of the frame and brake assembly; 
           [0032]      FIG. 6A-6B  are perspective views of an embodiment of the adjustable seat for an embodiment of the zip line system of the present invention; 
           [0033]      FIG. 7A-7B  are perspective views of a further embodiment of the adjustable seat for an embodiment of the zip line system of the present invention; 
           [0034]      FIG. 8  is a perspective view of an embodiment of the zip line system of the present invention with cable and tower. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0035]      FIG. 1  shows in general a zip line apparatus  10  of the present invention including a trolley  11  with a braking system  12  supported on an extended cable  14 . The trolley  11  comprises two frame pieces  16  that house one or more wheels  18  for engaging the cable  14 . The cable is understood to be in one embodiment an extended steel cable, but could alternatively be a rope, line, rail or wire, but for purposes of description is hereinafter referred to as cable  14 . The cable is fastened at either end between two spaced apart points B-C to generally define a longitudinal travel axis A for the trolley. The trolley  11  may also include a braking system  12 , handle  20 , a seat  22  and an adjustment mechanism  26  facilitating changing the spacing between the seat  22  and the trolley  11 . 
         [0036]    A basic zip line kit  30  is shown in  FIG. 2  and the components of the kit  30  are shown in  FIGS. 2A-2E  comprising the trolley  11 , handle  20 , braking system  12 , seat  22 , and adjustment mechanism  26 , respectfully. The kit  30  could alternatively include more or less components, for example, the kit might not contain the braking system  12  if such a braking system where not necessary or desired in a certain zip line application. The kit could, by way of example, also include additional components like the cable  14  and parts for securing and extending the cable  14  between the points B-C. 
         [0037]    The generally triangular shaped frame pieces  16  of the trolley  11  as shown in  FIG. 2A  define a series of pivot points  38 , attachment points  39  as well as other openings and slots to facilitate the attachment of the wheels  18 , secure the opposing frame pieces  16  together and position the braking system  12 , handle  20 , seat  28  and adjustment mechanism  26 . Pivot points  38  are positioned at what are defined here as the upper opposing corners of the trolley  11  to rotatably attach the wheels  18  between the triangular shaped frame pieces  16 . Two wheels  18  are used in the preferred embodiment although additional pivot points and wheels may be configured and overall dimensions of the frame pieces  16  may be altered to accommodate alternative configurations. 
         [0038]    The center portion of the trolley has an opening  40  for the handle  20  to be inserted through or bolted onto the frame  16 , the handle  20  may be a metal, wood or other similar rigid material bar or rod, which is inserted through the opening  40  so as to extend perpendicularly relative to the planar surface  42  of the frame  16  as shown in  FIG. 1 . The handle  20  may be round, or other profile such as square or rectangular with the opening  40  similarly designed, and be of a various diameter or width to comfortably accommodate the hands of a rider  24  gripping the handle  20  by wrapping their fingers around the handle  20 . 
         [0039]    The handle  20 , as shown in  FIG. 2B , may have a removable cushioned grip  44  that is slid onto or affixed onto the handle  20 , providing comfort to the rider  24  and helping to secure the handle in the opening  40  where the ends of the grips  44  abut against the portion of the frame  16  surrounding the handle opening  40 . In this way, the opening  40  in the frame  16  for the handle  20  may be of a diameter smaller than an outer circumference of the grip  44  providing for the grip  44  to maintain the handle  20  in the opening  40  with the trolley  11 . The grip  44  may be of a stiff foam or rubber that tightly adheres to the handle  20 , but is generally manually removable if necessary to remove the handle  20  from the trolley  11 . 
         [0040]    One embodiment of a seat  22  and the adjustment mechanism  26  as flexible fabric webbing is shown in  FIGS. 2D and 2E . The seat  22  may be of any ergonomical design and material to comfortably and safely support a rider  24 . In the embodiment of  FIG. 2D , the seat is designed to be sat upon by the rider with the seat  22  arranged under the user&#39;s hamstrings and/or gluteus maximus. The general diamond shape of the seat  22  here facilitates the rider sitting upon the seat and essentially straddling the webbing of the adjustment mechanism  26 . The seat  22  may be other shapes, and may be rigidly formed from a piece of metal, such as aluminum, or the seat may be flexible, i.e. a flexible fabric or plastic such that the flexible seat conforms to the riders body size and shape. This is an important safety consideration since a flexible seat would be able to bend around the body proportions of any size rider from child to adult, and securing them closely without changing the size of the seat for different riders. In either a rigid seat or a flexible seat, the seat may have cutouts  46 , slots  47  or other openings  50 , which define alternative securing points to allow flexibility in attachment of the seat  22  to the adjustment mechanism  26 . 
         [0041]    The adjustment mechanism  26  is in one embodiment fabric webbing  50  of a reasonable length, generally between for instance 2.44 m-4.57 (8-15 feet) long, to provide sufficient adjustment between the seat and trolley for the size of the rider. The critical distance for which the adjustment mechanism  26  is adjusted is based on the extension of the rider&#39;s arms over their head to grasp the handle  20  while sitting on the seat  22  so that their head is entirely below the trolley. In other words it is the distance between the handle  20  and the seat  22  which permits the rider to sit comfortably on the seat  22  and reach over their head and grasp the handle  20  so that they are securely suspended below the trolley  11  and upon the seat  22 . For a child the webbing would be adjusted to shorten the distance between the seat and trolley, and for an adult of course the webbing  50  would be lengthened to provide a greater distance therebetween. 
         [0042]    Although other ways of adjusting the relative seat and trolley distance are possible, webbing is a good choice for the adjustment mechanism because of its flexibility and tensile strength. The flexibility enables the user to easily adjust the length of webbing to accommodate a rider. Webbing is inexpensive, strong and available in a myriad of widths. An appropriate size for the adjustment mechanism  26  is a width of between about 1.91 cm-3.81 cm (¾″ to 1/½″) and preferably 1″ with a tensile strength of ˜15 kN-˜35 kN (˜3000 lb.-˜7000 lb.) and more specifically a tensile strength of ˜20 kN (˜4000 lb). The webbing is preferably resistant to mildew, aging and abrasion. Alternative adjustments and attachments of the frame to the seat are discussed in detail below. 
         [0043]    The braking system  12  as shown in one embodiment in  FIG. 2C  is also supported within the frame  16  of the trolley  11  and generally includes a brake pad  52  aligned anywhere adjacent the cable  14  for contacting the cable, although the most practicable alignment is above or below the cable  14  for contacting the cable  14  when the braking system  12  is operated by the rider. The brake pad  52  may have a contact length which depends on the amount of friction desired to be generated during braking operations. The contact length of the brake can be extended to the full length between the wheels  18  or to any desired length to sufficiently contact the cable  14  and create a frictional resistance to slow the trolley system  10  down upon actuation of the braking system. The brake pad  52  may be retained and float above the cable  14  using a tension spring or below the cable  14  resting on support or spacer  34  prior to activation. By floating adjacent the cable the brake pad  52  may be in light contact with the cable  14  and ride along the cable without creating much braking friction until energized by the rider. The brake pad  52  may also be provided with a contact surface which is angled or curved to provide additional frictional contact with the cable  14 . 
         [0044]    Turning to  FIG. 3A , in one embodiment, the two wheels  18  may be positioned at the upper corners of the trolley  11  providing spacing between the pivot points  38  in a range of at least 10.2 cm to 20.3 cm (4″ and 8″) and more specifically at a distance c of 11.4 cm to 14 cm (4½″ to 5½″). The wheels  18  are secured in the trolley  11  and thus along the cable  14  at an increased distance relative to known zip line systems so that rider, load or weight is distributed along a greater length and surface area of the cable  14  reducing tension and bending of the cable, giving the rider a smoother ride. The wheels  18  are generally fabricated of stainless steel, brass or other durable material with sealed, internal or external bearings  27  to optimize rolling and rotation of the wheels and trolley along the cable  14 . Such wheels  18  are often referred to as a sheave which is a wheel or roller with a groove  32  along its edge for engaging a belt, rope or cable  14 . When hung between two supports equipped with a belt, rope or cable  14 , one or more sheaves make up a pulley, or as in this case are embodied as the trolley  11 . The words sheave and pulley may be sometimes used interchangeably. 
         [0045]    Spacers  34  may be positioned between the frame and the connecting bolts  36  of the frame  16  and additionally at an offset to the pulleys  18  to act as a guide for the cable  14  along the pulley  18 . Optionally runners or brackets (not shown) may also be positioned offset from the pulleys to act as cable guides. 
         [0046]    In the embodiment as shown in  FIGS. 3A-3B , a U-shaped brake frame  54  is affixed in the frame  16  by a center connecting pin  36  and the brake frame  54  supports the brake pad  52  above the cable  14 . The brake frame  54  has an elongate slot  57  in which the center connecting pin  36  permits the brake frame  54  to move linearly up and down. In this embodiment, a leaf spring  58  is depicted, although any spring or retention support may be contemplated, to maintain the brake frame  54  in a disengaged position shown in  FIG. 3A . The leaf spring  58  has one end abutting the handle  20  and another end biasly engaging the brake frame  54  to maintain the brake frame  54  in a normally raised position, holding the brake pad  52  above, or in very slight or tenuous contact with the cable  14 . The brake pad has a cable engaging surface  59  and may be formed from a metal bar of steel, aluminum or other metals as shown in  FIG. 3A . The cable engaging surface  59  may be flat or it may be angularly formed or rounded to increase the overall contact area of the brake pad  52  with the cable  14  as shown in  FIG. 3B-3C . The brake pad cable engaging surface  59  may have a lining of a heat resistant material with a desired durability and coefficient of dynamic friction in a range of 0.35 to 0.42 meaning a force of 1000 kg (or pounds) will result in a brake force close to 400 kg (or pounds). 
         [0047]    As shown in an exploded view of the frame  16  and brake system in  FIG. 3B , the actuator  56  is coupled to the brake frame  54  and inserted through both legs of the U-shaped brake frame as shown. A central portion  60  of the actuator  56  provides a bearing or attachment point for a second end of the leaf spring  58  so that the leaf spring can directly influence the brake frame  54 . Alternatively, the second end of the leaf spring  58  can be directly affixed to the brake frame  54 . 
         [0048]    The actuator  56  is essentially a trigger for the user to actuate the brake. The ends of the actuator  56  pass through a brake pin slot  62  in each frame piece  16 , where the slot  62  is located above the handle opening  40  to allow for a rider  24  to easily grasp the brake actuator  56  with one or more fingers while still holding the handle  20 . In the present embodiment, with their hands grasping the handles  20 , the rider  24  can easily extend their pointer finger on either side of the trolley to engage the actuator  56  while continuing to maintain their grip on the handle  20 . In this way the rider can compress the actuator  56  to pull down the brake frame  54  and brake pad  52  against the bias of the leaf spring  58  and so fully engage the brake pad  52  with the cable  14 . As the brake pad  52  contacts the cable  14 , frictional resistance between the brake pad  52  and cable  14  is increased creating drag on the cable slowing the trolley  11  along the cable  14 . 
         [0049]    The actuator  56  inserted through the brake pin slot  62  in the frames  16  of the trolley  11  as shown in  FIG. 3C  facilitates easy actuation of the brake. The positioning of the actuator immediately above the handle  20  is ergonomically appropriate even for small or inexperienced riders. The ability for a rider  24  to grasp the actuator  56  while holding the handle  20  and pull down whenever the rider feels their speed is too great is critical as it allows the rider to hold or release the brake  12  in any desired manner to control their rate of travel, generally descent, along the cable  14 . 
         [0050]    In an alternative embodiment as shown in  FIG. 4  the brake frame  54  is supported in the disengaged position by one or more coil springs  64  influencing the brake frame  54 . A spring support  66  may be snapped or clamped on to the handle  20  or otherwise affixed to the frame  16  or brake frame  54 . Similar to the previous embodiment, the actuator  56  is inserted through the frame  16  and the brake frame  54  and actuated by pulling down the brake frame  54  and brake pad  52  using the actuator  56  to bring the brake pad  52  into contact with the cable  14 . 
         [0051]    Different types of springs and biasing devices may be used to bias the brake frame and brake pad  52 . In an alternative device, the brake pad  52  may be positioned below or to the side of the cable  14  with the coil springs  64  holding the brake frame  54  and brake pad  52  below and/or away from the cable  14 . The rider would then operate the actuator  56  to engage the braking system  12  and slow or stop the descent of the trolley along the zip line system  10 . 
         [0052]    In a further embodiment, the braking system  12  may be a simple lever pin  66  that is affixed to the actuator  56  and pivots on an axis Z around a lever midpoint, such as the connecting bolt  36  as shown in  FIG. 5A . The use of a smaller spacer  68  would allow the lever to be secured within the frame  16 , but also provide for an axis of rotation of the lever pin  66  about the bolt  36 . The lever pin  66  may have a brake pad  70  that extends along an entire length of the lever  66  from the actuator  56  to the pulley  18  or as shown in  FIGS. 5A-5C  a smaller surface area that contacts the wire  14  immediately at the pulley to curb rotation of the pulley  18  and slow the descent of the zip line system  10 . As shown in  FIG. 5B , the actuator  56  is inserted through an opening  69  in the lever pin, allowing the pin to swing down and pivot around the Z axis and force the opposing end of the lever pin  66  having the brake pad  70  to contact the cable  14 . 
         [0053]    As noted above the lever pin  66  may be positioned below the cable  14  as shown, or alternatively be positioned above the cable  14  by shortening the length of the lever  66  and repositioning the axis point Z perpendicular to a point in the center of the frame  16  near the area of the brake pin slot  62 . The actuator  56  and brake pin slot  62  would then be positioned at the opposite end of the lever brake pad  70  and be pulled or pushed up to actuate the braking system  12 . 
         [0054]    The lever pin brake pad may have a heat resistant lining made of a material with a high coefficient of dynamic friction as described above. In this embodiment with a simple lever, a spring may not be necessary if the brake pad  70  is permitted to merely float or glide along the cable  14  in the disengaged position and operation of the actuator  56  provides a greater frictional force from the brake pad  70  to the cable  14 . 
         [0055]    The present invention is not intended to be limited to only the braking systems described above. Other braking system structures could also be used to slow the trolley  11 , for example a braking system where the brake is generally in an actuated state, i.e. firmly gripping the cable and the actuation of the actuator  56  causes the braking system to essentially release the cable  14 . In this way, a rider would actively control their descent by releasing the brake a desired amount, and if their hands came off the trolley  11  and/or released the brake  12 , the trolley  11  would immediately slow due to the influence of the brake  12  on the cable  14 . 
         [0056]    The present invention also provides for alternative methods of attaching the frame assembly  16  to the seat  22  which supports the rider  24 . As shown in  FIGS. 6A and 6B  the frame  16  has a series of adjustment openings for linking and tightening the support webbing  26  to attach the seat or harness to the frame  16 . The support webbing  26  is first attached to the seat  22  by looping one or more straps of webbing  26  through one or more slots  47  or openings  50  in the seat or around a seat attachment beam  48 . A plastic roller  74  may be affixed to or snapped on to the opening or beam to smooth the surface edge and prevent cutting of the seat  22  into the strap  26 . The first end of the webbing  26  may be secured to the seat  22  or alternatively the strap  26  is looped through and around therefore providing two ends of the webbing  26  for attachment to the frame  16 . 
         [0057]    In a first embodiment, the webbing  26  is inserted through two attachment beams  48  and each webbing end  76  is drawn up to each of the two frame pieces  16 , with one end being looped through a first upper slot  78  of a first frame piece  16  and the other end being looped through a first upper slot  78  of the other frame piece  16 . Each of the webbing ends  76  for each frame piece  16  are then inserted through a lower slot  80  having teeth to grip the webbing  26  and secure the webbing at a specific length and position. As shown in  FIG. 6A , by inserting a longer length of webbing through each slot ( 78 ,  80 ) the distance d from the seat  22  to the frame  16  is shortened for a smaller rider  24  as compared to the distance D in  FIG. 6B . For a taller rider  24  with longer arm length, a shorter length of webbing is inserted through the slots ( 78 ,  80 ) leaving a greater distance between the seat and the frame and leaving a shorter length of webbing extending from the toothed slot  80 . The webbing  26  may be adjusted to any length that is comfortable for the rider. 
         [0058]    In a further embodiment as shown in  FIGS. 7A and 7B , one or more straps of webbing  26  may be attached or looped around attachment beams  48  or openings  50  on either end of the extended end of the seat  22  to form a swing to accommodate even smaller riders that may more easily hold onto the straps rather than the over head handle  20 . A preferred embodiment of the seat with a number of alternative attachment points using cutouts  46 , beams  48  or openings  50  is shown in  FIG. 7B , but numerous seat configurations are contemplated to safely support and adjust distances of the frame to the seat for comfort of the rider. In a further embodiment the number of openings  50  may be increased in number and size to provide for a leg and buttocks harness to be attached to the seat  22  to provide additional support and security to the rider. It is to be appreciated that the seat may also be a flexible seat  23 , such as a playground swing seat, supported on both ends and which is pliable enough to form around and hug the rider&#39;s body when the rider  24  sits in the middle of the seat as shown in  FIG. 8 . The rider  24  may hold on to the straps or alternatively reach around the straps to hold onto the handle  20 , allowing the pliable seat  23  and straps to curve around and safely secure the rider  24 . 
         [0059]    Actuation of the braking system as shown in  FIG. 9 , allows the rider  24  to slow down the zip line system  10 , prior to reaching the end of the cable  14 . Alternatively to the above described braking systems or in conjunction therewith, the trolley  11  can be stopped at the desired end of descent by a bumper or stopper  84  of a durable polymeric material such as high-density polyethylene (HDPE) or other comparable materials positioned close to the end of the cable  14 . The bumper  84  may be supported on the cable  14  and attached to an anchor point or points by shock cords  88 , or other type of force absorbing material which permits the bumper  84  and hence the trolley  11  to absorb all or some of the forces developed by the trolley  11  along the zip line and bring the trolley  11  to a safe stop. The braking system  12  provides additional safety and control to the rider to slow their descent and safely reach the ground or tower. The trolley braking system  12  and bumper  84  also provide control to the rider to ease the zip line system  10  to a stop in preference to bumping into the ground or an object and causing injury. 
         [0060]    The invention has been described in detail with particular reference to certain preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention.