Patent Publication Number: US-2022233341-A1

Title: Dynamic Metatarsal Roll Bar

Description:
PRIORITY 
     This application claims domestic benefit from pending provisional application no. 63/141,206, filed on Jan. 25, 2021, the contents of which are incorporated by reference. 
    
    
     FIELD OF INVENTION 
     The present invention relates to a footwear insert or a footwear midsole with improved support to the foot of a person walking or running. 
     BACKGROUND 
     The human foot is an overly complex mechanism. The many bones, muscles, ligaments, and tendons of the foot function to absorb and dissipate the forces of impact. During running or walking, the foot undertakes several different positions over the course of a single step and is subject to forces 2.5 times the person&#39;s body weight. 
     Metatarsalgia is an inflammatory pain felt mostly in the ball of the foot. It is especially common in women who wear fashion shoes and high heels. Women who have worn this type of footwear in the past are also prone to this type of foot pain, well after ceasing to wear high heeled footwear. Metatarsalgia can also be a problem for men and women who wear regular flat shoes. 
     Metatarsalgia is caused by the collapsing of the ‘transverse arch’ of the foot. The transverse arch runs across the forefoot and is formed by the five metatarsal bones. A collapse of the transverse arch will lower the transverse arch substantially, in turn putting pressure on the ball of the foot. Many factors can contribute to the collapse or lowering of the transverse arch, including age, muscle weakness, muscle strain, being overweight, wearing improper footwear, high heels, tight footwear, swelling of joints, or other medical conditions. 
     Untreated metatarsalgia may lead to pain in other parts of the same foot or may cause pain in the opposite foot and or elsewhere in the body. An altered gait from foot pain may also lead to pain in the back or hip. 
     It is desired to address metatarsalgia, and to provide an improved reduction of several common forefoot conditions including plantar fasciitis, as well as to encourage a more efficient propulsive phase during running and walking. 
     Lateral flexion of the foot may also cause strain on ankles and knees, as well as increasing pain levels. 
     Also, there is a present need for a shoe technology that accomplishes the goals of: (1) enhancing the efficiency of the propulsive phase during running and walking, (2) reducing forces on the plantar forefoot; (3) offering graduated support beneath the metatarsals; and (4) providing plantar flexion for active propulsion. 
     Existing devices used to address metatarsalgia include arch supports and cushioned inserts placed in a shoe beneath the ball of the foot. Arch supports help address the collapse of a transverse arch. Cushioned inserts reduce the impact of a stride with respect to the ball of the foot. However, such existing devices do not provide rigid support against lateral flexing of the foot. 
     SUMMARY 
     A Dynamic Metatarsal Roll Bar is a midsole footwear insert that provides support to a user&#39;s foot while the foot is subjected to the forces encountered in running or walking. The Dynamic Metatarsal Roll Bar promotes foot stability by reducing impact forces under the foot, limiting torsional flexing of the shoe, dispersing bottom pressure under the foot and decreasing forefoot flexion. The Dynamic Metatarsal Roll Bar promotes enhanced efficiency of the propulsive phase of walking, running by providing structures which reduce functional hallux limitus (FHL) and off load pressures under the metatarsophalangeal joints. 
     The Dynamic Metatarsal Roll Bar incorporates a rigid material incapsulated between the midsole and outsole of a shoe, where the rigid material is formed in a roughly planar lattice shape, formed of separate cells, and is located under the metatarsals of the wearer. The Dynamic Metatarsal Roll Bar provides firmer support beneath the metatarsal heads to reduce metatarsal plantar flexion during the propulsive phase of gait. The Dynamic Metatarsal Roll Bar provides support beneath the hallux to reduce hallux dorsiflexion during the propulsive phase of gait. The Dynamic Metatarsal Roll Bar is preferably custom contoured to the shape of the midsole and is lightweight. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a plan bottom view of the Dynamic Metatarsal Roll Bar. 
         FIG. 2  is a plan bottom view of the Dynamic Metatarsal Roll Bar, showing its placement within a right shoe midsole. 
         FIG. 3  is a cross-sectional view of the shoe midsole of  FIG. 2 , along line A-A of  FIG. 2 . 
         FIG. 4  is a cross-sectional view of the shoe midsole of  FIG. 2 , along line B-B of  FIG. 2 . 
         FIG. 5  is x-ray view of the Dynamic Metatarsal Roll Bar as it is encapsulated into the bottom of midsole of a shoe, and located in between the midsole and outsole. 
         FIG. 6  is an exploded perspective view of an illustrative embodiment of the Dynamic Metatarsal Roll Bar, shoe midsole and shoe outsole. 
         FIG. 7  is a plan view of three different configurations of the Dynamic Metatarsal Roll Bar, showing its placement within a shoe midsole. 
     
    
    
     DETAILED DESCRIPTION 
     The Dynamic Metatarsal Roll Bar, as a midsole footwear insert, constructed in accordance with the principles of the present invention is disclosed. The Dynamic Metatarsal Roll Bar is used within the midsole of a shoe. As a user&#39;s right shoe and left shoe are generally mirror images of one another, the Dynamic Metatarsal Roll Bar for the right shoe and left shoe would be mirror images as well. Only the right side Dynamic Metatarsal Roll Bar is illustrated in the Figures. A left shoe Dynamic Metatarsal Roll Bar is a mirror image construction of the left shoe Dynamic Metatarsal Roll Bar. 
     This invention helps promote foot stability by reducing impact forces under the foot, providing torsional flexing of the shoe, dispersing bottom pressure under the foot and decreasing forefoot flexion. 
     The Dynamic Metatarsal Roll Bar  100  is preferably formed as a lattice of a plurality of cells  20 , rather than a solid. A lattice of cells  20  provides strength to the Dynamic Metatarsal Roll Bar  100 , while keeping the weight to a minimum. The cells  20  of the lattice, each cell  20  formed by cell walls  21 , may be of any shape and may not necessarily be of a single shape. 
     In a preferred embodiment, the Dynamic Metatarsal Roll Bar  100  has a honeycomb structure, with hexagonal cells  20 . Such honeycomb structures can be as much as 40 times stronger than a solid of similar material and offer better weight-to-strength ratios. In addition, load carry and load transference qualities are much greater in honeycomb design structure. 
     The Dynamic Metatarsal Roll Bar  100  is formed in a slightly irregular rectangular or polygonal plane. The Dynamic Metatarsal Roll Bar  100  has roughly linear distal edge  102  and roughly linear proximal edge  104 . The Dynamic Metatarsal Roll Bar  100  has a slightly curvilinear medial edge  103  and lateral edge  101 , which edges follow, respectively, the curve of the medial and lateral border of the midsole  200  of an item of footwear. The curvilinear medial edge  103  and lateral edge  101  are curved or angled to follow the shape of the midsole  200  and outsole  300  which are usually curvilinear or linear. 
     Lateral edge  101 , distal edge  102 , medial edge  103 , proximal edge  104  form border  150 . Border  150  and the lateral, distal, medial and proximal edges are preferably formed of the same material as cell walls  21 . Border  150  surrounds and defines upper surface  110  and lower surface  111 . 
     The Dynamic Metatarsal Roll Bar  100  is positioned under forefoot area, namely the area that correlates with the metatarsal and phalanges of the user&#39;s foot. In particular, the Dynamic Metatarsal Roll Bar is positioned with distal edge  102  oriented toward the metatarsophalangeal joint of the foot, proximal edge  104  oriented toward the tarsometatarsal joint of the foot, medial edge  103  oriented toward the medial side of the foot, and lateral edge  101  oriented toward the lateral side of the foot. 
     The plane of the Dynamic Metatarsal Roll Bar  100  is preferably curved to follow the toe spring of the midsole  200 . Upper surface  110  is concave, providing a depression wherein a user&#39;s forefoot may be placed when Dynamic Metatarsal Roll Bar is in use. Preferably, lower surface  111  is parallel to upper surface  110 , and has a corresponding convex surface. 
     The Dynamic Metatarsal Roll Bar  100  has a firmer density and is stiffer than the surrounding midsole  200 . The difference in density and stiffness is accomplished by using different materials or varying the thickness of the Dynamic Metatarsal Roll Bar  100 . The use of different densities and hardness increases the performance of the shoe  500  in handling lateral force impacts and provides improved torsional stability. 
     The Dynamic Metatarsal Roll Bar can be made in a variety of materials such as carbon fiber, thermoplastic rubber or hard nylon, where the material provides a general rigid structure, resistant to flexing or bending. During a stride, this resistance to flexing provides additional support to the user&#39;s foot, especially under the metatarsals. The resistance to flexing prevents the foot from twisting in the middle of the stride. 
     The Dynamic Metatarsal Roll Bar is preferably between 0.5 mm and 2.5 mm thick, with 1.5 mm thickness being optimal. This thickness provides sufficient torsional rigidity. 
     In construction, midsole  200  preferably has recessed area to accommodate the Dynamic Metatarsal Roll Bar  100 , with a depth matching the thickness of the Dynamic Metatarsal Roll Bar to allow the outsole  300  to be smoothly attached. Encapsulating the 
     Dynamic Metatarsal Roll Bar  100  in the forefoot area of the midsole  200  reduces the forces against the medial plantar aspect of the heel by decreasing the supination and reducing pronation moments. 
     When the foot takes up a “neutral” (i.e., neither pronated or supinated) position, the Dynamic Metatarsal Roll Bar  100  applies a gentle forward motion movement while stabilizing movement to the forefoot. 
     When the foot moves into a pronated position, the Dynamic Metatarsal Roll Bar  100  disperses a higher magnitude of ground forces area beneath the forefoot. 
     By pronation “control,” we mean the increase in supination moments acting around the joints of the rearfoot and decrease the magnitude of pronation movement and plantarflexion during the propulsive phase of gait. 
     While certain novel features of the present invention have been shown and described, it will be understood that various omissions, substitutions and changes in the forms and details of the device illustrated and in its operation can be made by those skilled in the art without departing from the spirit of the invention.