Patent Publication Number: US-9840408-B2

Title: Retractable stirrup extension

Description:
BACKGROUND OF THE INVENTION 
     Field of the Invention 
     This invention relates to the field of equestrian equipment, and more particularly to an extendable stirrup that permits a rider to more safely and easily mount, ride and dismount a horse, or other rideable animal. 
     Description of Related Art 
     Traditionally, stirrups form parts of conventional horse mounting equipment and may be positioned on one or both sides of the saddle. Stirrups are designed not only to assist the rider in mounting, but also in maintaining balance during riding, and when dismounting. For safety while riding, the bottom, foot resting portion of the stirrup is generally located at a level where the rider&#39;s feet are comfortably engaged when the rider is in the saddle. 
     The construction of riding saddles and accessories suited to shorter riders, younger riders, and riders with decreased mobility present special challenges. For various reasons, a person often has difficulty mounting a horse. The primary difficulty is that a person must step very high in order to place their foot into a properly adjusted stirrup. Depending upon the height of the horse and the leg length of the rider, this may result in the stirrup being too high for the rider to easily engage for mounting the horse. Riders often attempt to overcome this difficulty by searching for something to stand on, or having another person physically assist them. Appropriate items, or persons, however, are often not available. 
     Another possibility is adjusting the stirrup to a lower than functional level for mounting. The stirrup strap normally includes a buckle, which allows the strap to be vertically adjusted to suit the individual rider. Typically, the desired length of the stirrup strap while riding in the saddle is too high for the rider to comfortably step up to mount the horse. Shorter people usually have the greatest difficulty because they must step proportionally higher than taller people, and this disparity is even greater when the horse is a taller horse. An adjustment to the length of the stirrup strap to minimize the step up generally requires the rider to be dismounted. Unfortunately, once adjusted, the height is fixed and now the rider must ride with a stirrup well below his/her foot. 
     This presents the additional problem of readjusting the stirrup when the rider is sitting in the saddle. Even a highly experienced rider is dangerously exposed to an accident while trying to perform this maneuver. When the rider, in the saddle, attempts to reach down for drawing up the stirrup, the required leaning to one side can lead to a fall. Using traditional stirrups, the only safe way to adjust the height is to have another person, one who is dismounted, adjust them for the rider. 
     In the alternative, a rider may attempt to climb upon an object such as a bucket, fence, stool, or ladder to reach the stirrup, but this also can lead to injury caused by the instability of the object or the animal moving at a critical time. On a trail ride, for example, one cannot always find something of the right height to stand on. Additionally, a horse is often nervous and fidgety when being asked to stand still next to an inanimate object while being mounted. 
     Relevant prior art falls into three broad categories. The first involves the use of an extra mounting strap attached to the stirrup strap or to the saddle, having a (adjustable) step fixed at a lower height. Examples of US patents include: U.S. Pat. Nos. 7,386,973; 6,688,088; 7,263,817; and 5,347,797. The second category involves the use of a rigid wire-rack that hooks onto the saddle strap and provides a lower step (see, e.g., U.S. Pat. No. 4,761,938). The third category involves the use of extendable and retractable plates or bars that provide a lower height step when extended. Examples of US patents include: U.S. Pat. Nos. 5,661,957; 7,380,390; 2,935,833; 8,413,411; 7,574,849; 6,173,558; 6,026,633 and 5,809,754. 
     Disadvantages with many of these devices include: (1) their mechanical complexity, (2) their cost, and (3) the problem with exposed or freely-hanging parts. In particular, devices that hang freely, or that leave the extended lower foot plate (step) in an extended position hanging below the stirrup, expose the rider to hazards from brush or low lying limbs of a tree that may snag the exposed parts of the device, thereby entangling the rider&#39;s leg and possibly causing a fall. This results in an undesirable level of risk for the trail rider (or for any riding that takes place outside of the safe confines of the clinical setting of a professional arena). 
     There is a need, hence, for a device for assisting in the mounting of a saddled animal, such as a horse, that is mechanically simple, low-cost, easily retracted, and safe for the rider as well as the animal. The device should allow a stirrup or foot plate to be easily extended towards the ground so that a short person, a child, or person of reduced mobility may easily mount a saddle positioned on a horse or pony. Once mounted, the rider should be able to be easily and safely retract and stow away the extended foot step. The device should be usable with either English (Eastern) or Western type of saddles and saddle hardware. 
     Against this background the present invention was developed. 
     SUMMARY OF THE INVENTION 
     The present invention, the Step Up Stirrup™, is a retractable stirrup extension for use with a saddle and horse, or other rideable animal. The extendable stirrup assembly includes a conventional stirrup with an upper (top) foot plate for supporting the rider&#39;s foot during riding, and which is hung from a saddle with a strap in a known manner; a cushioned foot pad; and a bottom foot plate retractably attached to the upper stirrup with an extension mechanism that provides 4-12 inches of vertical travel (extension). The bottom foot plate travels easily between an open (extended) and a closed (retracted) position. The bottom foot plate provides a lower “step” for the rider to use when mounting the horse. A latching mechanism can be used to lock the assembly in a compact, closed position, after the rider has mounted the horse. 
     With the Step Up Stirrup™ you don&#39;t have to bend over after mounting the horse. Once you are on the horse, you can reach for the stirrup leather at any part that is comfortable for the rider and lift the whole thing into the rider&#39;s lap and snap the assembly shut. Then, drop it back down and put the rider&#39;s foot in the stirrup. This is much easier to preform then trying to change buckles on the stirrup leather. In fact, some saddles make it almost impossible as they pull the buckle way deep into the saddle and are sort of stuck in there. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S) 
         FIG. 1  shows an elevation view of the front side of an example of a retractable stirrup extension in the closed position, according to the present invention. 
         FIG. 2  shows an elevation view of the front side of an example of a retractable stirrup extension in the partially-extended position, according to the present invention. 
         FIG. 3  shows an elevation view of the front side of an example of a retractable stirrup extension in the fully-extended, open position, according to the present invention. 
         FIG. 4  shows an elevation view of one side of an example of a retractable stirrup extension in the closed position, according to the present invention. 
         FIG. 5  shows an elevation view of one side of an example of a retractable stirrup extension in the fully-extended, open position, according to the present invention. 
         FIG. 6  shows an elevation view of the top of an example of a retractable stirrup extension, according to the present invention. 
         FIG. 7  shows an elevation view of the bottom of an example of a retractable stirrup extension, according to the present invention. 
         FIG. 8  shows an exploded, elevation view of the front side of an example of a retractable stirrup extension in the partially-extended position, according to the present invention. 
         FIG. 9  shows an isometric view of an example of a bottom foot plate, according to the present invention. 
         FIG. 10  shows an isometric view of an example of a side hinge block, according to the present invention. 
         FIG. 11A  shows a magnified, elevation view of the front side of an example of a retractable stirrup extension in the closed position, according to the present invention. 
         FIG. 11B  shows a magnified, elevation view of the front side of an example of a retractable stirrup extension in the closed position, according to the present invention. 
         FIG. 12  shows an isometric view of an example of a molded elastomeric top foot pad, according to the present invention. 
         FIG. 13A  shows a cross-section isometric view of an example of a molded elastomeric top foot pad inserted into a top foot plate, according to the present invention. 
         FIG. 13B  shows a cross-section isometric view of an example of a molded elastomeric top foot pad inserted into a top foot plate, according to the present invention. 
         FIG. 13C  shows an elevation view of the front side of an example of a retractable stirrup extension in the closed position, with an elastomeric foot pad/protective front cover, according to the present invention. 
         FIG. 13D  shows a cross-section elevation end view of an example of a molded elastomeric top foot pad/protective front cover covering an assembly in a closed position, according to the present invention. 
         FIG. 13E  shows a cross-section elevation end view of an example of a molded elastomeric top foot pad/protective front cover covering an assembly in an open position, according to the present invention. 
         FIG. 13F  shows a cross-section elevation end view of an example of a molded elastomeric top foot pad/protective front cover covering an assembly in an open position, according to the present invention. 
         FIG. 13G  shows a cross-section elevation end view of an example of a molded elastomeric top foot pad/protective front cover covering an assembly in an open position, according to the present invention. 
         FIG. 14  shows an elevation view of the front side of an example of a retractable stirrup extension in the closed position, according to the present invention. 
         FIG. 15A  shows an elevation view of the front side of an example of a retractable stirrup extension in the closed position, according to the present invention. 
         FIG. 15B  shows an elevation view of the front side of an example of a retractable stirrup extension in the closed position, according to the present invention. 
         FIG. 16  shows an elevation view of the front side of an example of a retractable stirrup extension in the closed position, according to the present invention. 
         FIG. 17  shows an elevation view of the front side of the example of  FIG. 16  of a retractable stirrup extension in a partially-open position, according to the present invention. 
         FIG. 18  shows an elevation view of the front side of the example of  FIG. 16  of a retractable stirrup extension in the open position, according to the present invention. 
         FIG. 19  shows an elevation view of the front side of an example of a retractable stirrup extension in the closed position, with a protective front cover, according to the present invention. 
         FIG. 20  shows an elevation view of the end of an example of a retractable stirrup extension in the closed position, with a protective front cover, according to the present invention. 
         FIG. 21  shows an elevation view of the front side of an example of a retractable stirrup extension in the closed position, with a protective, latching front cover, according to the present invention. 
         FIG. 22A  shows an elevation view of the end of an example of a retractable stirrup extension in the closed position, with a latching front cover, according to the present invention. 
         FIG. 22B  shows an elevation view of the end of an example of a retractable stirrup extension in the open position, with a latching front cover, according to the present invention. 
         FIG. 23  shows an elevation view of the end of an example of a retractable stirrup extension in the open position, with a protective, latching front cover, according to the present invention. 
         FIG. 24  shows an isometric perspective view of the end of an example of a bottom foot plate, with a pair of protective, latching front cover plates, according to the present invention. 
         FIG. 25  shows an isometric perspective view of the end of an example of a bottom foot plate, with a pair of protective, latching end strips, according to the present invention. 
         FIG. 26A  shows an elevation view of the end of an example of a retractable stirrup extension in the closed position, with a protective, latching end strip, according to the present invention. 
         FIG. 26B  shows an elevation view of the end of an example of a retractable stirrup extension in a partially-extended position, with a protective, latching end strip, according to the present invention. 
         FIG. 26C  shows an elevation view of the end of an example of a retractable stirrup extension in the open position, with a protective, latching end strip, according to the present invention. 
         FIG. 27  shows an elevation view of the front side of an example of a retractable stirrup extension in the closed position, according to the present invention. 
         FIG. 28A  shows a top view of the top side of an example of a bottom foot plate with a pair of recessed ramps, according to the present invention. 
         FIG. 28B  shows an elevation cross-section view of the side of an example of a bottom foot plate with a pair of recessed ramps, according to the present invention. 
         FIG. 29  shows an elevation end view of the side of an example of a bottom foot plate with a pair of recessed ramps, according to the present invention. 
         FIG. 30  shows an elevation view of the front side of an example of a retractable stirrup extension in the closed position, according to the present invention. 
         FIG. 31  shows an elevation view of the front side of an example of a retractable stirrup extension in the open position, according to the present invention. 
         FIG. 32  shows an elevation view of the front side of an example of a retractable stirrup extension in the closed position, according to the present invention. 
         FIG. 33  shows an elevation view of the front side of an example of a retractable stirrup extension in the open position, according to the present invention. 
         FIG. 34  shows an elevation view of the front side of an example of a retractable stirrup extension in the open position, according to the present invention. 
         FIG. 35  shows an elevation view of the front side of an example of a retractable stirrup extension in the closed position, according to the present invention. 
         FIG. 36A  shows an elevation view of the front side of an example of a retractable stirrup extension in the closed position, according to the present invention. 
         FIG. 36B  shows an elevation view of the side of an example of a retractable stirrup extension in the closed position, according to the present invention. 
         FIG. 36C  shows an elevation view of the side of an example of a retractable stirrup extension in the closed position, according to the present invention. 
         FIG. 36D  shows an elevation view of the side of an example of a retractable stirrup extension in the closed position, according to the present invention. 
         FIG. 36E  shows an elevation view of the side of an example of a retractable stirrup extension in the closed position, according to the present invention. 
         FIG. 37  shows an elevation view of the front of an example of a retractable stirrup extension in the closed position, according to the present invention. 
         FIG. 38  shows an elevation view of the front of an example of a retractable stirrup extension in the open position, according to the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention is a retractable stirrup extension, for use with a saddle and horse, or other rideable animal. The extendable/retractable stirrup assembly includes a conventional fixed stirrup with an upper (top) foot plate and a cushioned foot pad for supporting the rider&#39;s foot during riding, and which is hung from a saddle with a strap in a known manner. The stirrup extension further comprises a bottom foot plate extendably/retractably attached to the upper stirrup with an mechanical mechanism that provides, for example, 4-12 inches of vertical travel (extension). The bottom foot plate adjusts its position easily between an open (extended) position and a closed (retracted) position. The bottom foot plate provides a temporary lower “step” for use by the rider when mounting the horse. After mounting the horse, the bottom foot plate is retracted manually by the rider into a closed (retracted) position, which can be latched closed with a locking mechanism. 
       FIGS. 1-38  illustrate schematic details of various examples and embodiments of the present invention. Note that the terms “open position” and “extended position”, as it refers to the bottom foot plate, are equivalent. Likewise, the terms “closed position” and “retracted position”, as it refers to the bottom foot plate, are equivalent. We define the term “transverse” as a direction that is oriented perpendicular to the X-Y plane (i.e., the X-Y plane of the paper in  FIG. 1 ). 
     We define the term “extension ratio” as the ratio of two numbers, i.e. the length of travel, L, that the bottom foot plate travels when fully extended, divided by the width, W, of the foot bed across the top foot plate of the upper stirrup. In other words, the “extension ratio” is L/W. For example, if the width, W, of the top foot bed is 5 inches, then W=5. And, if the bottom foot plate drops down a total of 7 inches when fully extended, L=7, which gives an extension ratio L/W=7/5=1.4. 
     A useful range of extension ratios, L/W, for the present invention ranges from L/W=1 to 2, but it can be greater than 2 or less than 1. 
       FIG. 1  shows an elevation view of the front side of an example of a retractable stirrup extension assembly in the closed position, according to the present invention. Retractable stirrup extension assembly  10  comprises a conventional upper stirrup  12  and a retractable lower stirrup  2 . Upper stirrup  12  comprises a horizontal top foot plate  16  attached to vertical side stirrup legs  14 ,  14 ′, which are attached to upper arch  9 . Rubber (or other elastomer) foot pad  6  is disposed on top of top foot plate  16 . Side legs  14 ,  14 ′; top foot plate  16 , and upper arch  9  can be manufactured as a single, monolithic casting or machined piece of metal or metal alloy (such as steel or aluminum alloy), zinc alloy, magnesium alloy, polymer, or fiber-reinforced polymer. Stirrup  12  is suspended from a saddle (not shown) via stirrup strap  4  that passes though hole  8  in upper arch  9 . 
     In  FIG. 1 , stirrup assembly  10  further comprises a rigid bottom foot plate  24  that is retractably attached to stirrup  12 , and which is moveable vertically (extends downwards) to provide a lower “step” for the rider to use when mounting a horse (or other rideable animal). The amount of vertical travel (downward vertical extension) of bottom foot plate  24  can, for example, range from 4″ to 12″, depending on the design. More typically, the extension distance can range from 4″ to 8″. Bottom foot plate  24  can be made of metal or metal alloy (such as steel, aluminum alloy, zinc alloy, magnesium alloy, etc.), a rigid polymer or plastic, or a rigid fiber-reinforced polymer. An optional lower elastic pad,  48 , can be used to cushion the bottom foot plate  24 . Alternatively, the upper surface of bottom foot plate  24  can be mechanically roughened to provide extra grip for the foot. 
     In  FIG. 1 , bottom foot plate  24  is retractably attached to upper stirrup  12  via a pair of hinged linkages (plates)  20 ,  22 , and  20 ′,  22 ′, respectively that operate in parallel. Each hinge pin assembly comprises a hole (e.g.,  40 ) and a tightly-fitting hinge pin  53 ,  55 , or  57  (see  FIG. 8 ). Hinge pins  53 ,  55 ,  57  are typically made of steel, but can also be made of a self-lubricating, plastic material. Side block  18  is attached to side leg  14  and top plate  16  of stirrup  12  via a pair of screws  38  and  39 . Upper hinge plate  20  is pivotally attached to side hinge block  18  via first hinge pin  53 . Upper hinge plate  20  is also pivotally attached to lower hinge plate  22  via second hinge pin  55 . Finally, lower hinge plate  22  is pivotally attached to the vertical side leg  28  of bottom foot plate  24  via third hinge pin  57 . The long dimension of upper foot plate  16  defines the X-axis. Each hinge pin  53 ,  55 ,  57  is positioned so that its longitudinal axis is oriented transverse (perpendicular) to the X-Y plane of the device (i.e., the X-Y plane of the paper in  FIG. 1 ). Using this configuration of dual (parallel) pairs of linked hinge plates, rotary motion (pivoting) of the linked hinge plates about their respective pivots is converted into linear displacement of the common member (i.e., bottom foot plate  24 ) up and down along the vertical direction (Y-axis). 
     In general, making the hinge plates longer increases the vertical travel (extension) of the bottom foot plate  24 . 
     In  FIG. 1 , dual pairs of linked hinge plates ( 20 ,  22 ) and ( 22 ′,  22 ′) are made to be as long as possible, but not so long as to be touching or overlapping in the middle. 
     In general, the retractable stirrup extension assembly of the present invention can optionally comprise a latching mechanism that securely holds the bottom foot plate in a closed position when riding the horse. In one embodiment, a sufficient amount of friction can be provided between moving parts in the assembly so that the bottom foot plate remains in the closed position during riding. Alternatively, one or more high-strength magnets can be strategically placed to provide sufficient magnetic latching/clamping force to hold the bottom foot plate in a secure, closed position when riding the horse. Preferably, the latching mechanism operates automatically and securely without the need for intervention from the rider, other than manually pushing the bottom foot plate into its closed and latched position (the position illustrated, for example, in  FIG. 1 ). 
       FIG. 2  shows an elevation view of the front side of the example of a retractable stirrup extension from  FIG. 1 , in a partially-extended (dropped down) position, according to the present invention. 
       FIG. 3  shows an elevation view of the front side of the example of a retractable stirrup extension from  FIG. 1  in the fully-extended (fully-open) position, according to the present invention. In this example, if the inside width of the upper foot plate  16  is 5″, this then makes the vertical extension (drop-down distance) equal to about 7″. The extension ratio, L/W, is 7/5=1.4. 
       FIG. 4  shows an elevation view of one side of an example of a retractable stirrup extension  10  in the closed position, according to the present invention. Latching spring strip  34  can be seen. 
       FIG. 5  shows an elevation view of one side of an example of a retractable stirrup extension  10  in the fully-extended, open position, according to the present invention. Here, it can be seen that the upper right hinge plate  20  comprises a rigid pair of parallel hinge bars, right hinge bar  21  and left hinge bar  23 , joined together by recessed web  59  at the lower end. A series of holes  50  are drilled through each bar to reduce its weight. Upper hinge pin  53  connects upper right hinge plate  20  to stirrup  12 . Middle hinge pin  55  connects lower right hinge plate  20  to upper right hinge plate  22 . Lower hinge pin  57  connects lower right hinge plate  22  to the vertical right side wall  28  of bottom foot plate  24 . Right hinge bar  21  and left hinge bar  23  are joined together by recessed web  59 . Open central volume  27  is disposed in-between right hinge bar  21  and left hinge bar  23  to reduce weight, and to accommodate the folded configuration of the lower hinge plate  22  against the upper hinge plate  20 . Lower hinge plate  22  comprises a single bar (with drilled holes  50  to reduce weight), and is joined at the top to upper hinge  20  via middle hinge pin  55 ; and is further joined at the bottom to bottom foot plate  24  via lower hinge pin  57 . The use of recessed web  59  allows upper hinge plate  20  to fold tightly and compactly against lower hinge plate  22  (see, e.g.,  FIG. 1 ). Semi-spherical recess  49  can be seen. 
       FIG. 6  shows an elevation view of the top of an example of a retractable stirrup extension  10 , according to the present invention. Dashed line  54  and  54 ′ indicates the centerline of the hinge pins  53 ,  53 ′, respectively. 
       FIG. 7  shows an elevation view of the bottom of an example of a retractable stirrup extension  10 , according to the present invention. The bottom view essentially comprises a view of the bottom of bottom foot plate  24 . A series of holes  50  are drilled to reduce the weight, and the central volume  19  of the plate is open. Dashed line  54  indicates the centerline of the lower hinge pins  57 ,  57 ′. 
       FIG. 8  shows an exploded, elevation view of the front side of an example of a retractable stirrup extension  10 , laid out in a partially-extended position, according to the present invention. 
       FIG. 9  shows an isometric view of an example of a bottom foot plate  24 , according to the present invention. A semi-spherical indentation/recess  49 ′ can be seen on the short, vertical side wall  28 ′ of bottom foot plate  24 . This recess is disposed for receiving the semi-spherical latching element  36 ′ of latching mechanism  26 ′. Left- and right-sided recessed notch  254  and  254 ′ are disposed in vertical side wall  28 ′ of bottom foot plate  24  for engaging, mating, and interlocking with the lower hinge pin  57  of lower hinge plate  22 . The long sides  25 ,  25 ′ of plate  24  can be seen. A plurality of through holes  50  are drilled through plate  24  to reduce the weight. A large central open space  19  is disposed in the center of plate  24 . Optionally, the upper surface  51  of bottom plate  24  can be mechanically roughened to provide a non-slip surface for the rider&#39;s foot or boot. Hinge pin holes  47  and  47 ′ can be seen. 
       FIG. 10  shows an isometric view of an example of a side hinge block  18 , according to the present invention. Screws  38  and  39  (see  FIG. 8 ) attach side hinge block  18  to side leg  14  of stirrup  12  and to top plate  16  through holes  44  and  44 ′. Block  18  contains an offset side extension tube/cylinder  29 , which contains hole  40 . 
       FIG. 11A  shows a magnified, elevation view of the front side of an example of a retractable stirrup extension  10  in the closed position, according to the present invention. Here, latching mechanism  26  can be seen, which comprises two thin metal, spring-steel (leaf-spring) strips,  30  and  34 , of high strength steel, separated by a spacer pad  32 . Strips  30  and  34  are attached to side hinge block  18  via screws  38  and  39 . Semi-spherical screw-head  36  is screwed into the pair of spring strips  30  and  34 . Semi-spherical screw-head  36  serves as the latching element that inserts into the semi-spherical recess  49  in the vertical side wall  28  of bottom foot plate  24 . When inserted into recess  49 , the screw-head  36  holds (secures) bottom foot plate  24  against top foot plate  16  and prevents motion or vibration of the assembly  10  during riding. The curved shape (e.g., semi-spherical) of screw-head  36 , coupled with the use of a chamfered corner on vertical side wall  28  of bottom plate  24  ensures smooth, unassisted operation (i.e., no hands needed to pull outwards on the spring strips  30 ,  34 ) of the latching mechanism  26  when closing the assembly  10 . 
       FIG. 11B  shows a magnified, elevation view of the front side of an example of a retractable stirrup extension  10  in the partially-open position, according to the present invention. Here, the corner of the vertical side wall  28  of bottom foot plate  24  can be seen pushing on the semi-spherical screw-head  36 . Note: the corner of bottom foot plate  24  can be machined as necessary to make the latching operation run more smoothly. 
     In another embodiment, semi-spherical screw-head  36  can be replaced with a strong magnet to provide the latching force. Alternatively, semi-spherical screw-head  36  can be replaced with a wedge or triangle-shaped member to provide the latching function. 
       FIG. 12  shows an isometric view of an example of a molded elastomeric top foot pad  6 , according to the present invention. In this example, pad  6  (which can be made of rubber or a urethane compound, for example) comprises a pair of side walls  60 ,  60 ′ that are continuous with the top pad  6 . Side walls  60 ,  60 ′ cover and protect the front gap/opening between the top and bottom foot plates,  16  and  24 , respectively. This prevents any small branches or limbs of trees or brushes from accidently sticking into the open gap between the foot plates, possibly causing a fall. Pad  6  further comprises a molded central rib  62  and pair of flanges  64 ,  64 ′, which form an inverted “T” shape in cross-section. This “T”-shape allows the elastomeric pad  6  to be inserted into an opening in the top foot plate  16  and then secured by pushing the flanges  64 ,  64 ′ down and underneath top plate  16  (as can be seen in  FIG. 13A ). Side wall  60  further comprises an optional upside-down “U”-shaped opening  92  that acts a finger-hole for reaching in with a finger for grabbing the bottom foot plate  24  and pulling it down when opening the assembly  10 . Optionally, a pair of recessed cutouts (not shown) in the top foot plate  16  can be used to receive and hold the pair of flanges  64 ,  64 ′. In this case, the lower surface of flanges  64 ,  64 ′ is flush with the lower surface of top foot plate  16 . 
       FIG. 13A  shows a cross-section isometric view of an example of a molded elastomeric top foot pad  6  inserted into a top foot plate  16 , according to the present invention. The top cushion pad  6  comprises a downwardly-protruding central rib  62  that has a pair of sideways-extending flanges  64 ,  64 ′ that are configured for being pushed into an open channel (not numbered) disposed in the middle of top foot plate  16 , in-between front plate segment  16  and rear plate segment  16 ′, that receives and securely holds the central rib  62  and pair of flanges  64 ,  64 ′. In this example, the bottom part of side wall  60 ,  60 ′ comprises a hooked lower end  66 ,  66 ′, respectively. The hooked lower end  66 ,  66 ′ functions as a latch for holding assembly  10  in the closed position (See  FIG. 13D ). 
       FIG. 13B  shows a cross-section isometric view of an example of a molded elastomeric top foot pad  6  inserted into a top foot plate  16  in-between front plate segment  16  and rear plate segment  16 ′, according to the present invention. In this example, the bottom part of sidewall  60 ,  60 ′ comprises an inside-facing chevron or “Vee”-shaped lower end  66 ,  66 ′, respectively. The chevron-shaped lower end  66 ,  66 ′ can function as a friction member for holding assembly  10  in a closed position via friction. The stiffness and rigidity of the material (e.g., urethane) used for pad  6  aids in holding assembly  10  in a closed position. 
       FIG. 13C  shows an elevation view of the front side of an example of a retractable stirrup extension  10  in the closed position, with an elastomeric foot pad/protective front cover  60 , according to the present invention. Cover  60  comprises a notch  67 ,  67 ′. Cover side wall  60  further comprises an optional upside-down “U”-shaped opening  92  that acts a finger-hole for reaching in with a finger for grabbing the bottom foot plate  24  and pulling it down when opening the assembly  10 . 
       FIG. 13D  shows a cross-section elevation end view of an example of a molded elastomeric top foot pad/protective front cover  6 ,  60  covering an assembly  10  in a closed position, according to the present invention. In this example, interior hooks  66 ,  66 ′ function to latch and hold the bottom foot plate  24  when in the closed position. To release the latch, the rider must reach behind the cover side wall  60 ,  60 ′ and pull outwards to freely clear the interior hooks  66 ,  66 ′ from the corners of bottom foot plate  24 , before pulling down on bottom foot plate  24 . 
       FIG. 13E  shows a cross-section elevation end view of an example of a molded elastomeric top foot pad/protective front cover  6 ,  60  covering an assembly  10  in a closed position, according to the present invention. In this example, the bottom part of side wall  60 ,  60 ′ comprises an inside-facing chevron or “Vee”-shaped lower end  66 ,  66 ′, respectively. The bottom surface of the cover  60  can be flush with the bottom surface of bottom foot plate  24 . In some embodiments, longitudinal grooves  90 ,  90 ′ can be machined into the long side walls  25 ,  25 ′ of bottom foot plate  24 . Chevron-shaped grooves  90 ,  90 ′ serve to catch and hold the inwardly-facing chevron-shaped protrusions  66  and  66 ′, respectively, to provide a more securing latching function. 
       FIG. 13F  shows a cross-section elevation end view of an example of a molded/continuous elastomeric top foot pad/protective front cover  6 ,  60  covering the assembly  10  from  FIG. 13D  in an open position, according to the present invention. The sloped, interior ramp of the internal hooks  66 ,  66 ′ serve to smoothly spring-open the elastic cover plates  60 ,  60 ′ when bottom foot plate  24  is moved upwards during the closing process. 
       FIG. 13G  shows a cross-section elevation end view of an example of a molded elastomeric top foot pad/protective front cover  6 ,  60  covering the assembly  10  from  FIG. 13E  in an open position, according to the present invention. The sloped, interior ramp of the internal chevron-protrusions  66 ,  66 ′ serve to smoothly spring-open the elastic cover plates  60 ,  60 ′ when bottom foot plate  24  is moved upwards during the closing process. When the assembly is fully-closed, the interior chevron bumps  66 ,  66 ′ snap-shut in the bottom plate&#39;s longitudinal grooves  90  and  90 ′, respectively. 
       FIG. 14  shows an elevation view of the front side of an example of a retractable stirrup extension  10  in the closed position, according to the present invention. In this example, side hinge block  18  has been removed, and stirrup  12  has been made wider to accommodate the missing material. Additionally, a pair of hinge mounting tabs  70 ,  70 ′ have been added to the underside of top foot plate  16 . The mounting tabs  70 ,  70 ′ are made continuously integral (e.g., cast, integrally-machined, 3-D printed) with the top foot plate  16 . Upper hinge plate  20  is rotatably mounted to mounting tab  70  via hinge pin  53 . 
       FIG. 15A  shows an elevation view of the front side of an example of a retractable stirrup extension  10  in the closed position, according to the present invention. In this example, side hinge block  18  has been removed, and stirrup  12  has been made wider. Additionally, a pair of hinge mounting tabs  70 ,  70 ′ have been added to the underside of top foot plate  16 . The mounting tabs  70 ,  70 ′ are made continuously integral (e.g., cast, machined, 3-D printed) with the top foot plate  16 . Upper hinge plate  20  is rotatably mounted to mounting tab  70  via hinge pin  53 . A pair of recessed magnets,  172 ,  172 ′ are disposed in a recess on the underside of top foot plate  16 . Magnets  172 ,  172 ′ securely hold upper hinge plate  20 ,  20 ′, respectively, when the assembly  10  is folded in the closed position. In this case, upper hinge plates  20 ,  20 ′, must be made of a ferromagnetic material (e.g., steel). 
       FIG. 15B  shows an elevation view of the front side of an example of a retractable stirrup extension in the closed position, according to the present invention. Retractable stirrup extension assembly  10  comprises a conventional upper stirrup  12  and a retractable lower stirrup  2 . Upper stirrup  12  comprises a horizontal top foot plate  16  attached to vertical side stirrup legs  14 ,  14 ′, which are attached to upper arch  9 . In this example, side hinge block  18  has been removed, and stirrup  12  has been made wider. Additionally, a pair of hinge mounting tabs  70 ,  70 ′ have been added to the underside of top foot plate  16 . The mounting tabs  70 ,  70 ′ are made integral (e.g., cast, machined) with the top foot plate  16 . 
       FIG. 16  shows an elevation view of the front side of an example of a retractable stirrup extension  10  in the closed position, according to the present invention. In this example, hinge plates  20 ,  20 ′, and  22 ,  22 ′ are made longer than those previously shown (e.g.,  FIG. 1 ). In this case, the right, linked pair of upper and lower hinge plates  20 ,  22  overlap the left linked pair of upper and lower hinge plates  20 ′,  22 ′ by an overlap distance equal to about 25% to 75% of the length of one of the hinge plates. In other embodiments (not illustrated), the hinge plates can overlap as much as 75% of their length. Allowing for the hinge plates to overlap allows a greater vertical travel (extension) of the bottom foot plate  24 , while still having a compact configuration when closed. 
       FIG. 17  shows an elevation view of the front side of the example of  FIG. 16  of a retractable stirrup extension  10 , with overlapping hinge plates, in a partially-open position, according to the present invention. Because the hinge plates at long enough that they overlap when closed, a rotation of the bottom foot plate  24  of about 10° is required to prevent binding (touching) of the middle hinge pins when partially-extended. 
       FIG. 18  shows an elevation view of the front side of the example of  FIG. 16  of a retractable stirrup extension  10 , with overlapping hinge plates, in the open position, according to the present invention. In this example (which has 25% overlapping hinge plates), for a width=X of the upper stirrup (above top foot plate  16 ), this translates to a vertical extension=1.6 X. For example, if the width of the top foot plate is 5″, this translates to a vertical extension of 8″ when the assembly is fully open. The extension ratio is 8/5=1.6. 
       FIG. 19  shows an elevation view of the front side of an example of a retractable stirrup extension  10  in the closed position, with a protective front cover  72 , according to the present invention. Front cover  72  is made of sheet metal, and can be spot-welded to the top foot plate  16  via spot welds  74  (or attached with screws, not shown). Front cover plate  72  prevents any small branches or limbs of trees or brushes from accidently sticking into the open gap between the top and bottom foot plates, possibly causing a fall. Front cover  72  can comprise a finger hole  92  for aiding the release of bottom foot plate  24 . 
       FIG. 20  shows an elevation view of the end of an example of a retractable stirrup extension in the closed position, with a protective front cover  72 ,  72 ′ according to the present invention. Front cover  72  is made of sheet metal, and can be spot-welded to the top foot plate  16  via spot welds  74 . In this example, front cover  72 ,  72 ′ simply serves as a protective cover, and does not have a latching function. 
       FIG. 21  shows an elevation view of the front side of an example of a retractable stirrup extension in the closed position, with a protective, latching front cover  72 , according to the present invention. Front cover  72  is made of sheet metal, and can be spot-welded to the top foot plate  16  via spot welds  74 . The bottom edge  76  of cover  72  is turned up in the shape of a “J”, which acts as a hook to latch the bottom foot plate  24  when closed. 
       FIG. 22A  shows an elevation view of the end of an example of a retractable stirrup extension in the closed position, with a latching front cover  75 , according to the present invention. Hooked ends  76 ,  76 ′ grab the bottom surface of bottom foot plate  24  and holds it securely when in the closed position. Assembly  10  is released by reaching behind the cover plate  75  and pulling outwards on the hooked end  76 . 
       FIG. 22B  shows an elevation view of the end of an example of a retractable stirrup extension  10  in the open position, with latching front cover plates  75 ,  75 ′ according to the present invention. 
       FIG. 23  shows an elevation view of the front of an example of a retractable stirrup extension in the open position, with a protective, latching front cover plate  75 , according to the present invention. 
       FIG. 24  shows an isometric perspective view of the end of an example of a bottom foot plate  24 , with a pair of protective, latching front cover plates  75 ,  75 ′, according to the present invention, and J-hooks  76 ,  76 ′. 
       FIG. 25  shows an isometric perspective view of the end of an example of a bottom foot plate  24 , with a pair of protective, latching end strips  82 ,  82 ′, according to the present invention. Latching end strips  82 ,  82 ′ are made of sheet metal, and have a turned-up “J” hook  86 ,  86 ′ on the bottom edge, which serves to latch the bottom foot plate  24  when in a closed position. Assembly  10  is released by reaching behind the latching strips  82 ,  82 ′ and pulling outwards on the hooked ends  86 ,  86 ′. 
     Optionally (not illustrated) a pair of protective front cover plates (see, e.g., cover plates  75  and  75 ′ from  FIG. 24 ) can be added to the protective, latching end strips shown in  FIG. 25 , in order to cover the open gap between the top and bottom plates  16 ,  24  respectively. In this case, all four sides of the hinge plates would be fully covered (e.g., with sheet metal plates, or urethane rubber covers). 
       FIG. 26A  shows an elevation view of the end of an example of a retractable stirrup extension  10  in the closed position, with a protective, latching end strip  82 , according to the present invention. When moving the bottom foot plate  24  in an upwards direction from a partially-extended position, contact of the plate&#39;s corner with the sloped, ramp of the hooked, latching end  86  of strip  82  causes the latching end  86  to move to the right and spread open. Continual motion of the bottom foot plate  24  upwards causes the assembly  10  to close, up until the point is reached where the latching end  86  springs free of the bottom right hand corner of plate  24  and snaps shut underneath the bottom of bottom foot plate  24 , thereby latching closed the assembly  10 . 
       FIG. 26B  shows an elevation view of the end of an example of a retractable stirrup extension in a partially-extended position, with a protective, latching end strip  82 , according to the present invention. 
       FIG. 26C  shows an elevation view of the end of an example of a retractable stirrup extension  10  in the open position, with a protective, latching end strip  82 , according to the present invention. Note that the hooked lower end  86  of latching strip  82  touches the side of upper hinge plate  20  when the assembly is nearly 100% open. Stepping into the bottom foot plate  24  will provide enough force to fully open assembly  10 , thereby deflecting spring strip  82  outwards. However, after the foot has been removed, spring strip  82  will push back on upper hinge plate  20  and cause a small of rotation of hinge plate  20  back towards the closed position. This is a useful feature, because when a hand is placed on the bottom foot plate  24  and then force applied by the hand to push the bottom plate  24  upwards, the hinge assembly ( 20 ,  22 , and  20 ′,  22 ′) is already “pre-compressed” a small amount, which increases the ease of closing the assembly  10 . 
       FIG. 27  shows an elevation view of the front side of an example of a retractable stirrup extension in the closed position, according to the present invention. In this example, bottom foot plate  90  has a pair of left and right machined (or cast or 3-D printed) recessed ramps (ramped at about 10° from the horizontal) that allows a more compact configuration of hinge plates when folded up. Note: flange  64  of top pad  6  is shown, disposed just underneath top foot plate  16 . Top hinge plates  20 ,  20 ′ are rotated downwards slightly to accommodate the placement of flange  64 . 
       FIG. 28A  shows a top (plan) view of the top side of an example of a bottom foot plate  90  with a pair of left and right recessed ramps  192 ,  192 ′ down the center, according to the present invention. Recessed ramps  192 ,  192 ′ are angled at about 10° from the horizontal. The ramps provide extra, more compact space for holding the lower hinge plates  22 ,  22 ′, respectively. 
       FIG. 28B  shows an elevation cross-section view of the side of an example of a bottom foot plate  90  with a pair of recessed ramps  192 ,  192 ′ down the center, according to the present invention. Note that hinge pin holes  57 ,  57 ′ are located in the broad plane of plate  90  (as opposed to previously lying out of the plane and up on vertical side walls  28 ,  28 ′ of bottom foot plate  24  (See, e.g.,  FIG. 1 ). This also allows for a more compact configuration. 
       FIG. 29  shows an isometric perspective view of the side of an example of a bottom foot plate  90  with a pair of recessed ramps  192 ,  192 ′ down the center, according to the present invention. 
       FIG. 30  shows an elevation view of the front side of an example of a retractable stirrup extension  10  in the closed position, according to the present invention. In this example, a pair of magnets  104 ,  104 ′ are disposed within a pair of recesses on the underside of top foot plate  16 . Magnets  104 ,  104 ′, which function as the latching mechanism, are attached to top foot plate  16  with screws  112 ,  112 ′. Bottom foot plate  106 , which is made of a ferromagnetic material (e.g., steel), is held tight against the top foot plate  16  by magnetic force from the pair of magnets  104 ,  104 ′. The lower, retractable stirrup  101  is made of a thin, flexible braided or woven material  100 , such as: a strong, fiber-based (polyamide) Kevlar® cloth, Spectra® Cloth, Nylon® cloth, or a flexible, composite fiber-reinforced elastomeric material (such as rubber, urethanes, reinforced with fiberglass, polyamide, or steel fibers), which hangs freely in the middle as a loop of the flexible material  100 . The ends of lower stirrup  101  are attached to the vertical legs  14 ,  14 ′ of the upper stirrup  12  via clamping plates  102 ,  102 ′, which are, in turn, attached via screws  38  and  39 , respectively. The middle of flexible material  100  is attached to bottom foot plate  106  via a plurality of rivets  108 ,  108 ′. Note that the length of flexible stirrup  101  is unlimited, meaning that the distance of travel (extension) of bottom foot plate  106  is also unlimited (when unfolded). 
       FIG. 31  shows an elevation view of the front side of an example of a retractable stirrup extension  10  in the closed position, according to the present invention. When detached from the magnets  104 ,  104 ′, the bottom foot plate  106  falls down by gravity, and the flexible material  100  drapes into a natural “U” shape that comprises the lower stirrup  101 . 
       FIG. 32  shows an elevation view of the front side of an example of a retractable stirrup extension  10  in the open position, according to the present invention. In this example, the flexible material  100  that forms the lower stirrup  101  is folded up into a compact configuration. The extra folds of material  100  are held against the underside of bottom foot plate  106  via a second pair of magnets, i.e., side magnets  110 ,  110 ′. Note: this more compact configuration is less likely to accidently catch breaches or limbs than the version shown in  FIG. 30  (which has a pair of open loops of the flexible material  100  hanging from the sides). Note: in all of these embodiments, an optional front cover plate (not illustrated) can be used protect and cover the folded flexible material  100 , as previously illustrated. 
       FIG. 33  shows an elevation view of the front side of an example of a retractable stirrup extension  10  in the open position, according to the present invention. The pair of side magnets  110 ,  110 ′ are attached roughly 50% of the way down each side of the open loop of flexible material  100 . 
       FIG. 34  shows an elevation view of the front side of an example of a retractable stirrup extension  10  in the open position, according to the present invention. In this example, the lower, retractable stirrup  101  comprises a bottom foot plate  24  that is flexibly and retractably attached to upper foot plate  16  via a pair of flexible, parallel bicycle chains  120 ,  120 ′. The upper ends of chains  120 ,  120 ′ are pivotally attached directly to the left and right ends of upper foot plate  16 , respectively. A pair of latching end strips  122 ,  122 ′ are attached to legs  14 ,  14 ′ of upper stirrup  12  via screws  38 ,  39 . Note that the length of bicycle chains  120 ,  120 ′ is unlimited, meaning that the distance of travel (extension) of bottom foot plate  16  is also unlimited. Specifically, for the example illustrated in  FIG. 34 , for a width, W, of the top foot plate of 5″, the vertical drop down distance, L, is 9.2″. This gives an extension ratio, L/W=9.2/5=1.85. In other words, the drop down extension distance is almost twice the inside width of the top foot plate. 
     Note: the term “bicycle chain” is a generic term meant to include any type or form of “light duty roller chain” construction that has a large number of flexible linkages which are spaced a small distance apart. Generally, the material is made of steel, but plastic/polymer chains can be used as well. Bicycle-type chain links have the property of folding up in a single, flat plane, which aids the folding up of these chains up into a compact volume that sits just underneath the top foot plate  16 . 
       FIG. 35  shows an elevation view of the front side of an example of a retractable stirrup extension  10  in the closed position, according to the present invention. In this example, bicycle chains  120 ,  120 ′ are folded up (stowed away) in a compact configuration. Bottom foot plate  16  is securely held (latched) with the pair of latching end strips  122 ,  122 ′ attached to legs  14 ,  14 ′ of upper stirrup  12  via screws  38 ,  39 . An optional front cover plate (not illustrated) can be used protect and cover the folded set of chains  120 ,  120 ′. 
       FIG. 36A  shows an elevation view of the front side of an example of a retractable stirrup extension in the closed position, according to the present invention. Latching mechanism  130  comprises a pair of spaced-apart pins  132 ,  134  and a rubber (or other elastomeric material, e.g., urethane) band/tether/latch  136  hooked around both pins; wherein upper pin  132  is disposed on the side hinge block  18  (which is attached to top foot plate  16  via screws  38  and  39 ) and lower pin  134  is disposed on the vertical end  28  of bottom foot plate  24 . Rubber band  136  serves to elastically latch and hold together the bottom and top foot plates. Rubber band/tether  136  can comprise a molded tab at one end that fits tightly around the upper pin  132  so that the rubber band/tether doesn&#39;t fall off when not in use (i.e., when not latched). Alternatively, a crimp can be used to secure the one end of the rubber band to one of the pins. Alternatively, pins  132  and  134  can be hooks (not illustrated). 
       FIG. 36B  shows an elevation view of the side of an example of a retractable stirrup extension  10  in the closed position, according to the present invention. Latching mechanism  130  comprises an elastic latching member  136  hooked around two pins  132  and  134  disposed on top foot plate  16  and bottom foot plate  24 , respectively. Pins  132 ,  134  comprise domed heads for keeping the elastic member  136  from slipping off. In this example, elastic member  136  is depicted as a rubber band or loop of other elastic material. 
       FIG. 36C  shows an elevation view of the side of an example of a retractable stirrup extension in the closed position, according to the present invention. This example is similar to that shown in  FIG. 36B , except that the elongated latching member  136  comprises an elastomeric material (e.g., rubber or urethane) with holes  138 ,  139  at each end sized for conveniently stretching and slipping over upper and lower pin heads  132  and  134 , respectively. This configuration assures that the elastic member  136  is retained by the upper pin head (button) when not in use (i.e., when assembly  10  is extended). 
       FIG. 36D  shows an elevation view of the side of an example of a retractable stirrup extension  10  in the closed position, according to the present invention. This example is similar to that shown in  FIG. 36B , except that the latching mechanism  130  comprises a swinging (pivoting) latching member (i.e., clasp)  142  that pivots about the lower screw pin  146  and that has a hooked opening  148  at the upper end for latching/hooking onto upper pin  144 . 
       FIG. 36E  shows an elevation view of the side of an example of a retractable stirrup extension  10  in the closed position, according to the present invention. This example is similar to that shown in  FIG. 36B , except that the latching mechanism  130  comprises a strip of flexible material (e.g., leather, rubber, elastomer, braided or woven polyamide fiber cloth)  136  with snap closures  160 ,  160 ′ at both ends that attached to mating snaps  163 ,  163 ′ mounted on the top and bottom foot plates  16  and  24 , respectively. 
       FIG. 37  shows an elevation view of the front of an example of a retractable stirrup extension  10  in the closed position, according to the present invention. Reference is made back to  FIGS. 28 and 29 , which show a pair of continuously machined (or cast or 3-D printed) recessed ramps  192 ,  192 ′ along the central spine of the bottom foot plate  16 . This is what is shown in  FIG. 37 , where both the top and bottom foot plates  16 ,  24 , respectively have recessed ramps cutout in the plates. This allows the dual pairs of hinge plates  20 ,  22  and  20 ′,  22 ′ to be stowed in a compact configuration when closed. The ramps are cut at about a 10° angle from the horizontal. For the top foot plate  16 , there are two pairs of ramps  170 ,  170 ′ that are continuously machined (e.g., cast, 3-D printed) into the plate, one pair of ramps  170 ,  170 ′ on the front side, and one pair of ramps (not shown) on the back side of the plate (i.e., not down the central spine). Note: a latching mechanism is not illustrated in this Figure. 
       FIG. 38  shows an elevation view of the front of the example of  FIG. 37  of a retractable stirrup extension in the open position, according to the present invention. Top foot plate  16  has a left end  5 ′ and a right end  5  comprising left and right top transverse hinge pin holes  40 ′,  40 , respectively. 
     All sharp edges and corners of metal parts should be machined and rounded off to have corners with a radius greater than or equal to 1 mm. This is for preventing any sharp edges from hurting the horse. 
     The upper and lower stirrups can be powder-coated with one or more colorful coatings. Optionally, aluminum alloy parts can be anodized with various colors.