Abstract:
A force transfer harness that utilizes the harness structure to redirect the handler&#39;s forces through the harness structure and into the underlying ground is provided. The harness creates a moving support for a handler. Through the act of the dog sitting, the associated dog and handler cause a change in the orientation of the harness legs, both fixed and moveable, and cause the moveable legs to be brought into an angular relationship with the fixed legs that allows the harness to form a support structure. After the dog sits, the harness legs are brought in contact with the ground, whereas previously they were hovering above the ground in a ready orientation. As a result, the dog&#39;s act of sitting enables the human to transfer his or her weight through the harness and into the ground. As a consequence, the need to use a highly trained large breed dog for motion assistance is eliminated since all of the handler&#39;s forces are directed through the harness structure and into the ground rather than through the dog&#39;s body.

Description:
BACKGROUND OF THE INVENTION 
     A specially trained mobility assistance dog with associated mobility harness, often referred to as a walker dog, is used to assist individuals that have some form of impairment that makes it difficult for them to walk unassisted. The aforementioned impairment is often the result of a birth defect, physical injury, mental injury, or underlying disease such as Parkinson&#39;s disease or arthritis. The walker dog is often fitted with a mobility harness that transfers the forces exerted by the human handler into the dog&#39;s front shoulders and front legs. By using the dog fitted with the mobility harness as a “portable walker”, the handler gains assistance with balancing, gait, and their ability to ambulate. 
     Dogs of large stature are used as mobility assistance dogs due to the fact that the mobility harness transfers the forces exerted by the human handler into the dog&#39;s front shoulders and front legs. This facilitates the need for a large breed walker dog. The dog&#39;s girth and strength are the principal means used to provide stability and assistance to the handler. This is due to the fact that the dog needs to be able to support the handler&#39;s weight through its own front legs while additionally providing lateral support should the handler suddenly lose their balance. However, large breed dogs often don&#39;t fit well into many living environments. Additionally, about half of existing motion disabilities occur within the geriatric population. This group tends to have increased difficulties in caring for and living with larger breed dogs. 
     Given current harness designs, mobility assistance dogs require extensive training in paw placement and dog orientation relative to their handler&#39;s orientation, position, and gait. It is imperative that the walker dog keep his body parallel to that of the handler while keeping its front paws in perpendicular alignment to the handler. At the same time, the dog needs to be trained to walk when the handler is between strides in order to minimize the possibility of its front paws being out of alignment should the handler lose balance or start to fall. All of the aforementioned training is necessary since the dog must always be in a position to support the handler through its own shoulders and front quarters should the handler lose balance. All of the aforementioned coordination between the handler and the walker dog requires extensive training for the dog by itself, and the dog with the handler. At the same time, the temperament of the dog becomes an important factor in determining if the dog will ultimately be a successful walker dog. Additionally, training the dog to alert the handler to impending dangers such as oncoming traffic can be at odds with the dog&#39;s primary function of mobility assistance. This is due to the fact that a traffic danger warning is usually implemented by the dog moving to block the handler from entering the traffic zone which inherently puts the dog out of position relative to the handler for balance assistance. All of the aforementioned results in a dog selection and training regimen that is onerous to the dog and the handler. At the same time, the associated costs and time involved in training a walker dog limits their penetration within the disabled community. 
     Several different mobility assistance harnesses have been developed that allow for the transfer of forces into the dog&#39;s front quarters. As an example, Woerner, U.S. Pat. No. 7,281,363 describes a harness with a base member having a rigid platform covering a portion of the top side and a handle by which the handler&#39;s body forces are transferred to the dog&#39;s front quarters through the aforementioned platform. 
     Franck, U.S. Pat. No. 6,408,799 describes a harness that provides an improvement to the harness rigid handle allowing it to change orientation while still remaining rigid. A rigid handle is necessary to provide physical support and psychological assurance to the handler. However, Franck still requires that all forces are directed through the dog&#39;s front quarters. 
     Jenny, U.S. Pat. No. 7,140,326 describes a harness that comprises a rigid handle that is easily removable, via quick release joints. This patent provides an improvement over other rigid handle harnesses by providing for improved ergonomics with an easily removable rigid handle. 
     Woerner, Franck, and Jenny patents all provide for improvements over the standard rigid handle assistance dog harnesses. However, all of these patents still require that all of the handler&#39;s forces are directed through the harnesses into the dog&#39;s shoulders and front quarters. What is needed is a harness that is able to overcome the aforementioned limitation of directing all of the handler&#39;s forces through the dog&#39;s skeletal structure and thereby alleviate the need for a dog of large stature that requires extensive training. 
     SUMMARY OF THE INVENTION 
     The present invention provides a force transfer harness (“FTH”) that utilizes the harness structure to redirect the handler&#39;s forces, through the harness structure, and into the underlying ground. This alleviates the need to use a large breed dog for motion assistance when using the invention since all of the handler&#39;s forces are directed through the harness structure into the ground rather than through the dog&#39;s shoulders and front quarters. At the same time, the invention is easily adaptable to a medium size dog without the need for extensive mobility training that is associated with current mobility assistance dogs and harnesses. The FTH provides the stability through its structure rather than via the dog&#39;s girth. Additionally, the FTH provides on demand support should the handler suddenly lose balance and need to use the invention as an instantaneous means for support. Since the invention transfers the handler forces through its own structure and into the underlying ground, the need for the dog to maintain 100% alignment with the handler is eliminated. Therefore, the training required to coordinate the dog&#39;s motion and gate with that of the handler is also greatly reduced. 
     The FTH takes advantage of a dog&#39;s ability to sit on a given command. Through movement of the FTH handle, a verbal command, or the dog&#39;s training associated with harness load sensing, the dog responds by going into a sitting posture when the handler needs support. As the dog sits, the invention forms a support to allow the disabled person to fully transfer their weight through the FTH structure to the underlying ground without redirecting any forces through the dog. The result is a mobility assistance device that can utilize a medium sized dog having little additional mobility assistance training that still provides full on demand support for a disabled handler. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  is a front perspective view of the FTH shown in a orientation wherein the dog associated with the harness would be in a sitting position with the harness forming a support 
         FIG. 1B  is a rear perspective view of the FTH shown in a orientation wherein the dog associated with the harness would be in a sitting position with the harness forming a support 
         FIG. 2  is a front view of the FTH shown in a standby orientation where the harness handle is retracted down position 
         FIG. 3  is a front view of the FTH shown in an orientation wherein the dog associated with the harness would be in a walking position astride the human handler 
         FIG. 4  is a front view of the FTH shown in a position wherein the dog associated with the harness would be in a sitting position with the harness forming a support and showing the dog in a sitting position astride the human handler 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The present invention provides a FTH that utilizes the harness structure to redirect the handler&#39;s forces, through the harness structure, and into the underlying ground. As the harness handle is moved from its at rest position which has the handle near the dog&#39;s hind quarters, to a position that engages the hand of the human handler in which the handle position is roughly perpendicular to the underlying ground, a linkage between the handle and the harness moveable legs, causes a corresponding movement to occur in the harness support structure moveable legs. With the handle roughly perpendicular to the underlying ground the human handler is approximately astride the dog with the dog in a standing position. In this position the FTH moveable legs are partially descended towards the ground in a partially open inverted V shaped position while the harness fixed legs are parallel to the ground and parallel to the dog&#39;s back. At the same time the moveable harness legs are not in contact with the ground and therefore all forces exerted on the handle are being born by the dog. However, once the dog moves from the standing position to a sitting position the handle moves to its most forward position and the moveable legs, via an interconnecting linkage, correspondingly move to their maximum open position, make contact with the ground, and all forces are distributed through the handle to the legs and directly into the ground. In the sitting position the dog&#39;s hind quarter is now in contact with the ground, the FTH fixed legs are now in contact with the ground, and the moveable legs are also in contact with the ground. In this position the FTH is fully capable of supporting the entire human handler&#39;s weight without any of the weight being transferred into the dog&#39;s skeleton structure. 
     Through the act of sitting, the dog changes the orientation of the harness legs, both fixed and moveable legs, so that they are all now in contact with the ground, whereas previously they were hovering above the ground in a ready orientation. As a result, the dog&#39;s act of sitting enables the human handler to transfer his or her weight through the FTH and into the ground. Although the handle shaft remains approximately perpendicular to the ground as the dog transitions from a standing to a sitting posture, the angle between the harness handle and the fixed legs increases as the dog sits. This angular change moves the moveable legs by an interconnecting linkage and results in the angle between the fixed and moveable legs increasing so that a support structure is now formed between the fixed and moveable legs. Additionally, the fixed legs, which are parallel to the dog&#39;s back and terminate near the dog&#39;s hind quarters, are brought in contact with the ground. 
     Referring to  FIG. 1A , the FTH is shown in a front perspective view that would correspond to a position where the dog (not shown) would be in a sitting position. The handle  10  is fastened to the right handle shaft  11  by mechanical fasteners  13 . A mechanical fastener  13  may be a screw, alternatively a spring loaded pin, or some other mechanical fastener. Handle  10  is fastened to the left handle shaft  12  by mechanical fasteners not shown. The handle is adjustable to extend closer or further from the main harness body by refastening the handle  10  to alternative holes (not shown) in handle shaft  12  and handle shaft  11  via mechanical fasteners  13 . Handle  10 , which is fastened to handle shaft  11  and handle shaft  12  by fasteners  13 , are collectively known as the harness handle. Handle shaft  12  is attached to the left fixed harness leg  30  by a pivot pin  46 . The pivot pin  46  in this embodiment is a rivet, but can also be any mechanical fastener such as a lock pin, shoulder bolt, screw, or other mechanical fastener that fastens the two elements together while allowing the elements to pivot relative to one another. The forward movement of handle shaft  12  is limited by a stop block  48  that restricts the forward movement of handle shaft  12  relative to the left fixed harness leg  30 . 
     Left fixed harness leg  30  is fastened to handle shaft  12  via pivot pin  46 . At the same time left fixed harness leg  30  and right fixed harness leg  31  are each directly fastened to the harness body fabric  14 . In this embodiment the fabric  14  is fastened by means of mechanical screw fasteners (not shown). Other means of fastening the body fabric  14  to the fixed harness legs could include, but not be limited to, a sewn pocket, glue, or other known fastening means. The harness body fabric  14  keeps all components of the FTH secured to and in alignment with the dog&#39;s body. In this embodiment the body fabric is composed of a 1680 denier woven nylon material that has structure and stiffness to keep the left fixed harness leg  30 , and the right fixed harness leg  31 , in parallel alignment to one another while conforming to the dog&#39;s body. Other modifications to the body fabric material and body fabric construction will readily appear to those who are skilled in the art. Such modifications may include different material construction and material types such as woven polyesters, knitted polyesters, and woven cottons to name a few. Three straps  22  which each have one end attached to the left fixed harness leg  30  and the other end to right fixed harness leg  3   l  are used to secure the harness body fabric  14  to the dog. In this embodiment the straps  22  are fastened by means of mechanical screw fasteners (not shown). Further to this embodiment the straps are secured to themselves by hook and loop fasteners. Other modifications to the above embodiment will readily appear to those who are skilled in the art. Such modifications may include, for instance, strap and buckle fasteners of different configurations. Additionally, a single larger fastening strap across the dog&#39;s stomach, instead of this embodiment&#39;s three straps  22  might be sufficient as a means to secure the FTH to the dog&#39;s body. The primary requirement of the straps  22 , or alternative fastening means, is to secure the FTH to the dog&#39;s body without allowing for significant movement of the harness once it is attached. At the same time the straps  22  should allow for quick and easy application and removal of the harness to the dog without causing discomfort to the dog while the FTH is secured to the dog. 
     The left fixed leg  30  has a telescoping foot  24  that allows the effective length of the fixed leg  30  with foot  24  to be adjusted to different lengths. The telescoping foot  24  is adjusted to different lengths by depressing a spring detent pin  26  that engages different predrilled holes (not shown) in the fixed leg  30 . In this way the total length of fixed leg  30  plus telescoping foot  24  can be adjusted to approximately match the back length of the associated dog whereas the bottom edge of the foot  24  approximately aligns with the dog&#39;s hind quarter. Other adjustment mechanisms for altering the length of the fixed leg might include, but not be limited to, a telescoping foot with a screw length adjustment to name one. Additionally, the spring detent spring  26  could be replaced by other mechanical means of securing the foot  24  to the fixed leg  30  such as a thumb screw to name one. 
     The left moveable leg  16  has a telescoping foot  20  that allows the effective length of the moveable leg  16  with foot  20  to be adjusted to different lengths. The telescoping foot  20  is adjusted to different lengths by depressing a spring detent pin  18  that engages different predrilled holes (not shown) in the moveable leg  16 . In this way the total length of moveable leg  16  plus telescoping foot  20  can be adjusted so that the orientation of the harness handle is approximately perpendicular to the ground  34  when the dog is in a sitting position and the harness is transferring the human handler&#39;s weight into the ground  34 . Right moveable leg  17  has a corresponding telescoping foot  21  that is also adjusted by depressing in a spring detent pin  19  that engages different predrilled holes (not shown) in the moveable leg  17 . Other adjustment mechanisms for altering the length of the moveable leg might include, but not be limited to, a telescoping foot with a screw length adjustment to name one. Additionally, the spring detent pin  18  could be replaced by other mechanical means of securing the foot  20  to the moveable leg  16  such as a thumb screw to name one. The same apples to the spring detent pin  19  that could be replaced by other mechanical means of securing the foot  21  to the moveable leg  17  such as a thumb screw to name one. 
     The left moveable leg  16  is attached to the left fixed harness leg  30  by a pivot pin  42 . The pivot pin  42  in this embodiment is a rivet, but can also be any mechanical fastener such as a lock pin, shoulder bolt, screw, or other mechanical fastener that fastens the two elements together while allowing the elements to pivot relative to one another. The left moveable leg  16  is attached to one end of the left linkage  28  by a pivot pin  44 . The other end of the left linkage  28  is connected to the left handle shaft  12  by a pivot pin  40 . The pivot pins  40  and  44  in this embodiment are rivets, but can also be any mechanical fasteners such as lock pins, shoulder bolts, screws, or other mechanical fasteners that fastens the elements together while allowing the elements to pivot relative to one another. As the left handle shaft  12  is moved in an arc relative to the left fixed leg  30 , a corresponding movement occurs in the movable leg  16  via linkage  28 . 
     Referring to  FIG. 1B , the FTH is shown in a rear perspective view that would correspond to a position where the dog (not shown) would be in a sitting position. In this view, we can see that right handle shaft  11  is attached to the right fixed harness leg  31  by a pivot pin  39 . The pivot pin  39  in this embodiment is a rivet, but can also be any mechanical fastener such as a lock pin, shoulder bolt, screw, or other mechanical fastener that fastens the two elements together while allowing the elements to pivot relative to one another. The forward movement of handle shaft  11  is limited by a stop block  37  that restricts the forward movement of right handle shaft  11  relative to the right fixed harness leg  31 . Consequently, the harness handle made up of handle  10 , handle shaft  11  and handle shaft  12 , is limited in forward movement by stop block  37  and stop block  48  ( FIG. 1A ). Additionally, since harness handle  10  is rigidly fastened to both handle shaft  11  and handle shaft  12  by fasteners  13 , the entire harness handle moves as a single unit whose forward movement is limited by stop block  37  and simultaneously stop block  48  ( FIG. 1A ). 
     Right fixed harness leg  31  is fastened to handle shaft  11  via pivot pin  39 . The right fixed leg  31  has a telescoping foot  25  that allows the effective length of the fixed leg  31  with foot  25  to be adjusted to different lengths. The telescoping foot  25  is adjusted to different lengths by depressing a spring detent pin  49  that engages different predrilled holes (not shown) in the fixed leg  31 . In this way the total length of fixed leg  31  plus telescoping foot  25  can be adjusted to approximately match the back length of the associated dog whereas the bottom edge of the foot  25  approximately aligns with the dog&#39;s hind quarter. Other adjustment mechanisms for altering the length of the fixed leg might include, but not be limited to, a telescoping foot with a screw length adjustment to name one. Additionally, the spring detent spring  49  could be replaced by other mechanical means of securing the foot  25  to the fixed leg  31  such as a thumb screw to name one. 
     The right moveable leg  17  is attached to the right fixed harness leg  31  by a pivot pin  45 . The pivot pin  45  in this embodiment is a rivet, but can also be any mechanical fastener such as a lock pin, shoulder bolt, screw, or other mechanical fastener that fastens the two elements together while allowing the elements to pivot relative to one another. The right moveable leg  17  is attached to one end of the right linkage  29  by a pivot pin  43 . The other end of the right linkage  29  is connected to the right handle shaft  11  by a pivot pin  41 . The pivot pins  43  and  41  in this embodiment are rivets, but can also be any mechanical fasteners such as lock pins, shoulder bolts, screws, or other mechanical fasteners that fastens the elements together while allowing the elements to pivot relative to one another. As the right handle shaft  11  is moved in an arc relative to the right fixed leg  31 , a corresponding movement occurs in the movable leg  17  via linkage  29 . Since harness handle  10  is rigidly fastened to both handle shaft  11  and handle shaft  12  by fasteners  13 , the entire harness handle moves as a single unit whose forward movement is limited by stop block  37  and simultaneously stop block  48  ( FIG. 1A ), and the corresponding movement of right moveable leg  17  and left moveable leg  16  will occur at the same time, and right moveable leg  17  and left moveable leg  16  will be limited in movement by their corresponding linkages  29  and  28  ( FIG. 1A ). 
     Referring to  FIG. 2 , a front view of the FTH is shown in a standby orientation where the harness handle is in a retracted down position and the dog is shown. The handle  10  is resting just above the harness body fabric  14  which is situated on the dog  32  back. Left moveable leg  16  is now forming an angle A with respect to left fixed leg  30 . Right moveable leg  17  ( FIG. 1B ) is now forming an angle A with respect to right fixed leg  31  ( FIG. 1B ). At the same time, left handle shaft  12  is forming an angle B with respect to left fixed leg  30 . Right handle shaft  11  ( FIG. 1B ) is forming an angle B with respect to right fixed leg  31  ( FIG. 1B ). The position of left moveable leg  16  is dictated by the position of the left handle shaft  12  and is brought to its position by the interconnection of the left handle shaft  12 , and left moveable leg  16 , via left linkage  28 . Likewise, the position of right moveable leg  17  ( FIG. 1B ) is dictated by the position of the right handle shaft  11  ( FIG. 1B ) and is brought to its position by the interconnection of the right handle shaft  11  ( FIG. 1B ), and right moveable leg  17 , via right linkage  29  ( FIG. 1B ). In this embodiment in the standby orientation shown, angle A is defined as 3.5 degrees and angle B is defined as 23 degrees. It should be clear to anyone skilled in the art that by making changes to linkage lengths and connection point locations that these angles can differ from the preferred embodiment. In this standby orientation the dog is able to sit, walk, or lay down with minimal interference from the FTH. 
     Referring to  FIG. 3  is a front view of the FTH shown in an orientation whereas the dog  32  associated with the harness would be in a walking position astride the human handler  36 . The left handle shaft  12  is in the vertical position defined as being approximately perpendicular to the ground  34 . The right handle shaft  11  ( FIG. 1B ) is in the vertical position defined as being approximately perpendicular to the ground  34 . The left fixed leg  30  is approximately parallel to the ground  34  and in line with the back of the dog  32 . The right fixed leg  31  ( FIG. 1B ) is approximately parallel to the ground  34  and in line with the back of the dog  32 . The FTH is located on the dog  32  by having the harness body fabric  14  in contact with the body of the dog  32  and being held in place by the straps  22 . Both the human  36  and the dog  32  have their legs in contact with the ground  34  and the human  36  is walking astride the dog  32 . At the same time, the human  36  is holding onto the harness handle  10  with his or her associated hand. The position of the left moveable leg  16  is dictated by the position of the left handle shaft  12  and is brought to its position by the interconnection of the left handle shaft  12 , and left moveable leg  16 , via left linkage  28 . The position of the right moveable leg  17  ( FIG. 1B ) is dictated by the position of the right handle shaft  11  ( FIG. 1B ) and is brought to its position by the interconnection of the right handle shaft  11  ( FIG. 1B ), and right moveable leg  17  ( FIG. 1B ), via right linkage  29  ( FIG. 1B ). In this embodiment in the walking position orientation shown, angle A is defined as 44 degrees and angle B is defined as 90 degrees. It should be clear to anyone skilled in the art that by making changes to linkage lengths and connection point locations that these angles can differ from the preferred embodiment. The angle A that is formed between the left moveable leg  16  and the left fixed leg  30  now forms a partial support formation between the aforementioned fixed leg  30  and moveable leg  16 . The angle A that is formed between the right moveable leg  17  ( FIG. 1B ) and the right fixed leg  31  ( FIG. 1B ) now forms a partial support formation between the aforementioned fixed leg  31  ( FIG. 1B ) and moveable leg  17  ( FIG. 1B ). It should be further noted that neither telescoping foot  20  located on the moveable leg  16 , telescoping foot  21  ( FIG. 1B ) located on the moveable leg  17  ( FIG. 1B ), telescoping foot  24  located at the end of the fixed leg  30 , and telescoping foot  25  ( FIG. 1B ) located at the end of the fixed leg  31  ( FIG. 1B ) are not in contact with the ground  34 . As a result, any forces that the human handler  36  is applying to the FTH are being born by the dog  32  in its front quarters. However, if the dog  32  goes from the walking orientation into a sitting posture, telescoping foot  20  located on the moveable leg  16 , telescoping foot  21  ( FIG. 1B ) located on the moveable leg  17  ( FIG. 1B ), telescoping foot  24  located at the end of the fixed leg  30 , and telescoping foot  25  ( FIG. 1B ) located at the end of the fixed leg  31  ( FIG. 1B ) would now be brought into contact with the ground  34  and all of the forces that the human handler  36  is applying to the FTH would now bypass the skeletal structure of dog  32  and be transferred through the FTH and into the ground  34 . At the same time angle A and angle B as defined above would both increase in response to the dog going into a sitting posture. 
     Referring to  FIG. 4  is a front view of the FTH shown in an orientation whereas the dog  32  associated with the harness would be in a sitting position astride the human handler  36 . The left handle shaft  12  is in the vertical position defined as being approximately perpendicular to the ground  34 . The right handle shaft  11  ( FIG. 1B ) is in the vertical position defined as being approximately perpendicular to the ground  34 . However, unlike the standing dog position of  FIG. 3 , the action of the dog sitting has increased the angle B to 139 degrees while angle A has increased to 77 degrees. Telescoping foot  20  located on the moveable leg  16 , telescoping foot  21  ( FIG. 1B ) located on the moveable leg  17  ( FIG. 1B ), telescoping foot  24  located at the end of the fixed leg  30 , and telescoping foot  25  ( FIG. 1B ) located at the end of the fixed leg  31  ( FIG. 1B ) are now all in contact with the ground  34 . As a result, the forces that the human handler  36  is applying to the FTH are being transferred from the harness handle  10 , into the left handle shaft  12  and right handle shaft  11  ( FIG. 1B ), then into the respective left fixed leg  30  and the right fixed leg  31  ( FIG. 1B ), and ultimately into the underlying ground  34  via the respective telescoping foot  24  located at the end of the fixed leg  30 , and telescoping foot  25  ( FIG. 1B ) located at the end of the fixed leg  31  ( FIG. 1B ). At the same time, some of the forces are being transferred through the left moveable leg  16  and the right moveable leg  17  ( FIG. 1B ) and then into the underlying ground  34  via the respective telescoping foot  20  located at the end of the left moveable leg  16 , and telescoping foot  21  ( FIG. 1B ) located at the end of the right moveable leg  17  ( FIG. 1B ). In the sitting position, the forward movement of left handle shaft  12  is limited by a stop block  48  that restricts the forward movement of left handle shaft  12  relative to the left fixed harness leg  30 . Additionally, the forward movement of right handle shaft  11  ( FIG. 1B ) is limited by a stop block  37  ( FIG. 1B ) that restricts the forward movement of right handle shaft  11  ( FIG. 1B ) relative to the right fixed harness leg  31  ( FIG. 1B ). Consequently, the harness handle made up of handle  10 , handle shaft  12  and handle shaft  11  ( FIG. 1B ), is limited in forward movement by stop block  48  and stop block  37  ( FIG. 1B ). Therefore, the forward movement of the left moveable leg  16  and the right moveable leg  17  ( FIG. 1B ) is constrained by the respective linkages  28  and  29  ( FIG. 1B ) connection to the respective left fixed leg  30  and right fixed leg  31  ( FIG. 1B ).