Abstract:
A stroller system including a rear suspension system comprising two springs is discussed. The stroller system is configured to withstand a variety of operating conditions including various terrain, speed and weight requirements. An embodiment of a stroller with a dual elastic suspension system is also discussed.

Description:
PRIORITY 
       [0001]    This application claims priority to U.S. Provisional Application No. 62/114,348 filed on Feb. 10, 2015, the contents of which are hereby incorporated by reference. 
     
    
     TECHNICAL FIELD 
       [0002]    The disclosure relates to strollers, and more particularly strollers with a rear suspension system. 
       BACKGROUND 
       [0003]    Strollers have been known and used for a number of years to provide a comfortable device to move a passenger such as a baby or a small child. There is a need for a stroller to provide a smooth and comfortable ride for both the occupant and user of the stroller under a variety of conditions including different terrain characteristics, weights/loads placed on the stroller, user speeds, and the like. 
       SUMMARY 
       [0004]    Disclosed is a stroller with a dual spring rear suspension mechanism. An outer spring is configured to provide a softer or cushioned feel to the passenger(s) and/or user when a user applies downward pressure on the rear handle of the stroller. An inner spring is configured to provide sufficient rigid support in order to carry heavy loads and prevent the suspension system from reaching its extreme compression limits. 
         [0005]    A first exemplary embodiment of the stroller may have a base, a first, front, frame member, a second, rear, frame member, and a pair of laterally spaced apart wheels. The base may have a first end, a second end, and two parallel elongated portions extending therebetween. The first frame member may be connected to the base proximate the first end of the base. The second frame member may be connected to the base proximate the second end of the base. The pair of laterally spaced apart wheels may be located proximate the second end of the base. Each of the wheels may further comprise a suspension system. The suspensions system further comprises a first suspension structure fixedly attached to one of the two parallel elongated portions extending between the first and second ends of the base, a second suspension structure with a first end pivotally attached to the first suspension structure and a second end coaxially aligned with and attached to a spring suspension structure. 
         [0006]    The spring suspension structure may also have a lower portion with a top surface, a housing structure with a first end and a second tapered end, a first spring, a second spring and a receiving element. The first spring may be contained within the housing structure and the top surface of the lower portion may be a first stop surface for the first spring and an inner housing structure contained within the housing structure may be a second stop surface for the first spring. The second spring encircles the housing structure and the first end of the second spring may be at the top surface of the lower portion and the second end may be at a base of the second tapered end of the housing structure. The receiving element of the spring suspension structure may be embedded within the one of the two parallel elongated portions configured to hold the tapered end of the housing structure. The laterally spaced apart wheels may be connected via at least one cross member. An exemplary embodiment of the stroller may further comprise a braking mechanism. 
         [0007]    In a further exemplary embodiment, the stroller may have a dual elastic suspension apparatus comprising a first member fixedly attached to a frame of the stroller, a second member movably attached to the first member and an elastic system positioned between the second member and the frame of the stroller. The elastic system may also have a housing structure positioned between the second member and the frame of the stroller, a first elastic element contained within said housing structure, and a second elastic element surrounding said housing structure. The elastic system may be configured to dampen motion between the second member and the frame of the stroller. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
         [0008]    The invention may be understood by reference to the following description taken in conjunction with the accompanying drawings, in which, like reference numerals identify like elements, and in which: 
           [0009]      FIG. 1  illustrates a front side perspective view of a stroller system with a dual spring suspension mechanism. 
           [0010]      FIG. 2  illustrates a rear side perspective view of a portion of stroller system with a dual spring suspension mechanism. 
           [0011]      FIG. 3  illustrates a side view of a dual spring suspension mechanism for a stroller system. 
           [0012]      FIG. 4  illustrates a rear side perspective view of a dual spring suspension mechanism for a stroller system. 
           [0013]      FIG. 5  illustrates a side perspective view of a dual spring suspension mechanism for a stroller system. 
           [0014]      FIG. 6  illustrates a rear side perspective view of a dual spring suspension mechanism for a stroller system. 
           [0015]      FIG. 7  illustrates a rear side perspective view of a dual spring suspension mechanism for a stroller system. 
           [0016]      FIG. 8  illustrates a rear view of a dual spring suspension mechanism for a stroller system. 
           [0017]      FIG. 9  illustrates a side view of a cross-section of a dual spring suspension mechanism for a stroller system. 
           [0018]      FIG. 10  illustrates a rear perspective view of a cross-section of a dual spring suspension mechanism for a stroller system. 
       
    
    
     DETAILED DESCRIPTION 
       [0019]    Disclosed herein is a stroller with a dual spring rear suspension mechanism. An outer elastic element or spring is configured to provide a softer or cushioned feel to the passenger(s) and/or user when a user applies downward pressure on the rear handle of the stroller. An inner elastic element or spring is configured to provide sufficient rigid support in order to carry heavy loads and prevent the suspension system from reaching its extreme compression limits. The stroller may have suspension mechanisms located on either side of its body and such opposing suspension mechanisms may be mirror images of each other. As a result, references to a single suspension mechanism may be applied to all suspension mechanisms located on the stroller. 
         [0020]    An exemplary embodiment of the stroller comprises a base, a first (front) frame member, a second (rear) frame member, and two pairs of laterally spaced apart wheels. The base may have a first end, a second end, and two parallel elongated portions extending therebetween, and the base may be extendible from a first length to a second length. The first front frame member may be connected to the base proximate the first end of the base. The second rear frame member may be connected to the base proximate the second end of the base. One pair of laterally spaced apart wheels may be located proximate the second end of the base. Each of the rear wheels may further comprise a suspension system. 
         [0021]    A stroller system  100  with a first front frame member  101  and a second rear frame member  103  is depicted in a front perspective view in  FIG. 1 . The first front frame member  101  may further comprise a first seat  105 . In some embodiments, the second rear frame member  103  may also contain means for accommodating a second passenger. The first front frame member  101  and the second rear frame member  103  may be connected by a base  107  comprising two parallel elongated portions which connect to the lower ends of the front frame  101  and the rear frame  103 . In one embodiment the base  107  may be expandable, such that the distance between the first front frame member  101  and the second rear frame member  103  is increased when the base  107  is expanded. The stroller system  100  is substantially symmetrical with rear wheels  109  located proximate the lower ends of the second rear frame member  103 . 
         [0022]    A rear perspective view of the stroller system  100  is depicted in  FIG. 2 . As illustrated, a suspension system  111  may be located proximate the rear wheel  109 , and as show, laterally between the two rear wheels  109 . The suspension system  111  and rear wheel  109  assembly may be located at each of the two sides of the stroller  100 . In general, the stroller system of the present invention comprises two mirror-imaged structural frames connected to each other by cross members. As the cross members may be placed in any suitable position, and since the structural frame members are mirror images, the discussion of the structure of the present invention will focus on a single frame. One skilled in the art will recognize that the description will apply equally to the mirrored frame. Each suspension system  111  and rear wheel  109  assembly may optionally be connected by a wheel axle tube  115 . The stroller system  100  may further comprise one or more brake pedals  113  used in a braking system including a brake axle tube  114 , adapted to simultaneously operate brakes on both rear wheels  109 . Alternatively, each rear wheel may have its own brake. 
         [0023]      FIG. 3  provides a side view of a rear wheel  109  of the stroller system. Visible through the spokes  110  of the rear wheel  109  is a portion of the suspension system  111 . 
         [0024]      FIG. 4  provides a rear perspective view of the suspension system  111 . The rear wheel  109  is not depicted in this figure. As depicted, the suspension system  111  comprises a first suspension structure  121 , a second suspension structure  123  and a third suspension structure  130  comprising spring  129 . The first suspension structure  121  is at least partially connected to the base  107  proximate the rear end of the base  107 B, and may be of unitary construction with the base  107 , welded to the base  107  or fixed to the base in some other manner. The first suspension structure  121  is pivotally connected to the second suspension structure  123  about the axis formed by pin  119 . In one embodiment, the second suspension structure  123  comprises two separated plates spaced such that the first suspension structure  121  fits within the two plates of the second suspension structure  123  proximate a first end of the second suspension structure  123 . The plates may be connected to each other or both of unitary construction, thus consisting of a single element. In one embodiment, the location  119  at which the first suspension structure  121  is pivotally connected to the second suspension structure  123  is fixed. Alternatively, the first suspension structure  121  and/or the second suspension structure  123  may contain grooves, tracks, paths, and the like, such that the position of the first suspension structure  121  with respect to the second suspension structure  123  may be adjusted by the user. In one embodiment, a pin inserted into a pin hole  122  engages with a slot  126  located on the first suspension structure  121  (further detail on slot  126  may be seen in  FIG. 10 ). The first suspension structure  121  may be locked into place with respect to the second suspension structure  123  so as to prevent the first and second suspension structures from separating. At the same time, the structures may allow for the second suspension structure  123  to rotate upwards about the connection point/location  119  towards the first suspension structure  121 . The direction of movement taken by  123  is illustrated by arrow  124 . 
         [0025]    The second suspension structure  123  also comprises means  125  for rotatably attaching a rear wheel  109  thereto. The second suspension structure  123  attaches to the third spring suspension structure  130  proximate a second end  117  of the second suspension structure  123 . The second end  117  of the second suspension structure  123  is located at an opposing end to the first end  119  of the second suspension structure  123 . The second suspension structure  123  may be configured so that the third spring suspension structure  130  fits within the opposing plates proximate the second end  117  of the second suspension structure  123 . The second suspension structure  123  may be fixed to the third spring suspension structure  130  by a pin  117   a  or other element which coaxially aligns the second end of the second suspension structure  117  the brake axle tube  114 , and at least one plate of the lower portion of the third spring suspension structure  127 . The third spring suspension structure  130  further comprises an upper portion  133  proximate the rear end of the base  107 B, a spring retainer or housing structure  131 , an outer spring  129 , and the lower portion  127 , adapted to engage the second suspension structure  123 , about pin  117   a  or some other mechanism to facilitate engagement with the second suspension structure  123 . In one embodiment, the plates of the second suspension structure  123  are composed from a single injection molded piece with left and right support plates and three mount points  119 ,  125  and  117 . 
         [0026]    A second, side perspective view of the stroller system with the dual spring suspension mechanism is illustrated in  FIG. 5 . A third, rear side perspective view of the stroller system with the dual spring suspension mechanism is illustrated in  FIG. 6 . A fourth, side perspective view of the stroller system with the dual spring suspension mechanism is depicted in  FIG. 7 ; in this figure, the rear wheel  109  is attached. A fifth, rear view of the stroller system with the dual spring suspension mechanism is depicted in  FIG. 8 ; again, the rear wheel  109  is attached. 
         [0027]      FIG. 9  illustrates a side view of a partial cross-section of the dual spring suspension mechanism depicted from the interior of the stroller, facing outwards from an interior portion of the stroller.  FIG. 10  illustrates a rear perspective view of the partial cross-section of the dual spring suspension mechanism, viewed from the outside of the stroller looking inwards. As depicted, the lower end of the outer spring  129  is coupled to a lower portion  127  of the third spring suspension structure  130 . The upper end of the outer spring  129  is coupled to the upper portion  133  of the third spring suspension mechanism. The upper portion  133  of the third spring suspension mechanism may form a substantially v-shaped receiving element  135  which is adapted to engage the rear portion of the base  107 B, and receives the upper portion  137  of the spring retainer or housing structure  131 . In one embodiment the upper portion  137  of the spring retainer or housing structure  131  may be convex or tapered. In one embodiment the upper portion  137  of the spring retainer or housing structure  131  may comprise a pin  138  configured to hold the upper portion  137  of the spring retainer or housing structure  131  in place with respect to the receiving element  135 . The pin  138  may prevent vertical movement of the spring retainer or housing structure  131  with respect to the base  107 . In one embodiment, receiving element  135  may be connected to the upper portion  137  of the spring retainer or housing structure  131  prior to attachment to the base  107 , with the receiving element  135  then being connected to the base  107  using a snap fit, rivet or other connection means. The outer spring  129  surrounds a spring retainer or housing structure  131 . The spring retainer or housing structure  131  has a top portion  132  of substantially larger diameter than that of the lower portion, thereby forming a lip to engage an end of the outer spring  129 . Enclosed within the spring retainer or housing structure  131  is a second spring system. The second spring system comprises an inner spring  141  which encircles an inner spring retainer  139 . An upper end of the inner spring  143  may be coupled to a surface formed by the sides of the inner spring retainer  139 , thereby forming a lip to engage one end of the inner spring  141 . The lower end of the inner spring  145  may be coupled to the interior surface of the spring retainer or housing structure  131 . In one embodiment, each of the inner spring  141  and the outer spring  129  may comprise a compression spring such that the springs resists compression when the stroller rests on a supporting surface, thereby provide an upwards force. In one embodiment, the outer spring  129  may be longer than the inner spring  143 , such that the outer spring is engaged in compression at all times, but the inner spring  141  only engages the inner spring retainer  139  upon compression of the spring mechanism  130  a sufficient distance to allow the spring  141  and inner spring retainer to meet. This engagement of the inner spring  141  only upon a predetermined level of compression of the outer spring  129  provides for a suspension system that allows a soft ride under normal conditions, but provides additional support and shock absorbtion in instances of extra compression of the springs  129 ,  141 . In one embodiment, the outer spring may be compressed one inch for every 30 pounds of force, and the inner spring  141  may be compressed at the rate of one half inch for every 25 pounds of force. The compression levels of the springs may be chosen to suit desired application of the stroller and suspension system. 
         [0028]    In alternative embodiments, a biasing and/or shock absorbing element other than or in addition to the spring may be utilized. 
         [0029]    In an alternative embodiment, the stroller comprises a dual elastic suspension apparatus. The dual elastic suspension apparatus comprising a first member fixedly attached to a frame of the stroller, a second member movably attached to the first member and a spring system positioned between the second member and the frame of the stroller. In this embodiment the elastic system comprises a housing structure positioned between the second member and the frame of the stroller, a first elastic element contained within the housing structure and a second elastic element surrounding the housing structure. In this embodiment, the elastic system is configured to dampen motion between the second member and the frame of the stroller. 
         [0030]    Although the invention has been described in terms of exemplary embodiments, it is not limited thereto. Rather, the appended claims should be construed broadly to include other variants and embodiments of the invention which may be made by those skilled in the art without departing from the scope and range of equivalents of the invention. This disclosure is intended to cover any adaptations or variations of the embodiments discussed herein.