BACKGROUND OF THE INVENTION 1. Field of the Invention
The present invention relates to an in-shoe support device, and in particular to an in-shoe support device for heeled shoes, that could create a better body weight distribution. Herein, the heeled shoe is referred to as a shoe that raises the heel of the wearer's foot higher than the toes. As such, the high heeled shoe is a kind of heeled shoe.
2. The Prior Arts
Usually, wearing heeled shoes could create slender body proportions and add formality to any outfit. However, there is the long-standing problem that wearing heeled shoes could cause discomfort or even more serious sequela to the feet.
Even though academic research indicates that the heel wedge angle of the heeled shoe is related to the problem of uneven distribution of weight, to be more precisely, excess stress on the forefoot, there is no proper device for solving this problem.
At present, a lot of designs are proposed for solving the problem of uneven distribution of weight when wearing shoes. However, they are not able to effectively solve the problem of uneven distribution of weight when wearing heeled shoes. So far no inventor has provided an anatomical and biomechanical analysis of the problem of uneven distribution of weight on a foot when wearing heeled shoes.
From the anatomical, morphological and biomechanical point of view, the problem of uneven distribution of weight when wearing heeled shoes can be analyzed as follows. Firstly, refer to FIG. 1, for a top view of a foot bone anatomy. As shown in FIG. 1, the foot bone anatomy includes a forefoot 10, a midfoot 20, and a rearfoot 30. The forefoot 10 contains a plurality of phalanges 12 and a plurality of metatarsals 14. The midfoot 20 contains three cuneiform bones 22, a cuboid 24, and a navicular 26. The rearfoot 30 contains a talus 32 and a calcaneus 34. The talus 32, the tibia 36 (as shown in FIGS. 2A and 2B), and the fibula (not shown) form the ankle joint 38.
Corresponding to the foot bone anatomy in FIG. 1, FIG. 2A and FIG. 2B show a cross-sectional view of a foot bone anatomy when wearing a flat shoe and a heeled shoe respectively. FIG. 2A shows a cross-sectional view of foot bone anatomy when a user standing on the ground 1000 or wearing a flat shoe. Under this situation, weight is evenly distributed in a forefoot load-bearing region 40A and a rearfoot load-bearing region 42A. FIG. 2B shows a cross-sectional view of the foot bone anatomy and a heeled shoe when a user wearing a heeled shoe. Under this situation, weight is mainly distributed in a forefoot load-bearing region 40B and in a rearfoot load-bearing region 42B. The heeled shoe places the wearer's foot essentially on an inclined plane, whereupon the front of the foot is lower than the heel. This shifts the center of mass in the body forward and creates forward sliding of the foot of the wearer relative to the shoe. For that reason, body weight has fallen mainly in the forefoot load-bearing region 40B. Moreover, since phalanges 12 bend up at the joint where phalanges 12 and metatarsals 14 meet, there is an increased amount of weight to the forefoot 10. Therefore, the pressure in the forefoot load-bearing region 40B is several times the pressure in the rearfoot load-bearing region 42B. For instance, for a user wearing 3-inch high heeled shoes, the pressure in the forefoot load-bearing region 40B is 8 to 9 times the pressure in the rearfoot load-bearing region 42B.
When wearing heeled shoes, the center of mass in the body is shifted forward. Therefore, the forefoot 10 bears most of weight, while the rearfoot 30 bears substantially less weight. This effect can cause many foot problems if wearing heeled shoes for a long period of time.
FIG. 3A is a top view of the distribution of left foot pressure when a user wearing a heeled shoe. FIG. 3B is a top view of the respective regions of the bones of the human foot corresponding to FIG. 3A. As shown in FIG. 3A and FIG. 3B, the forefoot 10 and rearfoot 30 are the main regions of load-bearing. Most of the pressure is distributed on the forefoot 10. In addition, there is at least one significant high pressure region, such as the high load-bearing region 16. However, there is no or very low pressure on the midfoot 20. To be more specific, the midfoot 20 can further be divided into three regions, which are a lateral region 200, a central region 202, and a medial region 204. By comparing FIG. 3A with FIG. 3B, the lateral region 200 and the medial region 204 can only bear partial weight. However, the central region 202 bears no or very little weight. Therefore, high-heeled shoes cause the problem of uneven distribution of weight, to be more specific, increased pressure in the forefoot 10. Conventional heeled shoes with lateral arch support pads or medial arch support pads might increase weight-bearing pressure in the lateral region 200 or the medial region 204, but not in the central region 202.
Therefore, up to now, the design and function of in-shoe support pad for heeled shoes is not quite satisfactory, and it leaves much room for improvement.
SUMMARY OF THE INVENTION In general, high-heeled shoes cause uneven distribution of weight and increased pressure in the forefoot. In order to overcome these problems, the present invention provides an in-shoe support device which can increase the contact area of the midfoot and rearfoot, transfer weight from the forefoot to the midfoot and rearfoot, decrease the pressure on the forefoot, decrease the heel wedge angle and increase wearer's comfort. The present invention provides an in-shoe support device which can easily be adapted to any style heeled shoe without the need to modify a shoe or a shoe last. This device may be placed by the wearer or incorporated into the shoe or insole during the manufacturing process.
According to an embodiment of the present invention, the present invention provides an in-shoe support device for heeled shoes comprising a main body, which includes a first end and a second end. The second end is disposed opposite to the first end. The maximum thickness of said main body is disposed in a location between the first end and the second end, and the maximum thickness decrements from that location to the first end and the second end. The main body is divided into three portions, which are a first support portion, a second support portion, and a third support portion. The first support portion extends from said the first end to said the second end. The third support portion extends from the second end to the first end. The second support portion is a middle portion which connects the first support portion and the third support portion. Wherein, the length of the main body is defined as the distance between the first end and the second end. The length of the first support portion is about 20% to 45% of the length of the main body. The length of the second support portion is about 10% to 30% of the length of the main body. The length of the third support portion is about 30% to 55% of the length of the main body.
Preferably, the second end is located corresponding to the wearer's calcaneus, while the maximum thickness is located corresponding to the midfoot.
Further scope of the applicability of the present invention will become apparent from the detailed descriptions given hereinafter. However, it should be understood that the detailed descriptions and specific examples, while indicating preferred embodiments of the present invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the present invention will become apparent to those skilled in the art from this detailed descriptions.
BRIEF DESCRIPTION OF THE DRAWINGS The related drawings in connection with the detailed descriptions of the present invention to be made later are described briefly as follows, in which:
FIG. 1 is a top view of a foot bone anatomy according to the Prior Art;
FIG. 2A is a cross-sectional view of the foot bone anatomy when a user standing on the ground or wearing a flat shoe;
FIG. 2B is a cross-sectional view of the foot bone anatomy and a heeled shoe when a user wearing a heeled shoe;
FIG. 3A is a top view of the distribution of left foot pressure when a user wearing a heeled shoe;
FIG. 3B is a top view of the respective regions of the bones of the human foot corresponding to FIG. 3A;
FIG. 4A is a top view of an in-shoe support device for heeled shoes according to an embodiment of the present invention;
FIG. 4B is a side cross-sectional view of an in-shoe support device for heeled shoes according to an embodiment of the present invention;
FIG. 5A is a side cross-sectional view of a heeled shoe for which the device of the present invention has been installed;
FIG. 5B is a side cross-sectional view of the foot bone anatomy and a heeled shoe for which the device of the present invention has been installed as shown in FIG. 5A;
FIG. 5C is a side cross-sectional view of an in-shoe support device installed in a heeled shoe, when it is worn by a user according to an embodiment of the present invention;
FIG. 6A is a top view of the distribution of right foot pressure when a user standing with a heeled shoe for which the device of the present invention has not been installed;
FIG. 6B is a top view of the distribution of right foot pressure when a user standing with a heeled shoe for which the device of the present invention has been installed;
FIG. 7A is a top view of the distribution of right foot pressure when a user walking with a heeled shoe for which the device of the present invention has not been installed; and
FIG. 7B is a top view of the distribution of right foot pressure when a user walking with a heeled shoe for which the device of the present invention has been installed.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT The purposes, construction, features, functions and advantages of the present invention can be appreciated and understood more thoroughly through the detailed description below and attaching referenced drawings.
Refer to FIGS. 4A and 4B respectively for a top view of an in-shoe support device 50 for heeled shoes according to an embodiment of the present invention; and a side view of an in-shoe support device 50 for heeled shoes according to an embodiment of the present invention. These two figures are used to describe the thickness distribution of the in-shoe support device 50 for a heeled shoe according to an embodiment of the present invention. The in-shoe support device 50 includes a main body 60. The main body 60 has a first end 62 and a second end 64. The second end 64 is disposed opposite to the first end 62. The length of the main body 60 is defined as a distance between the first end 62 and the second end 64. A maximum thickness H of the main body 60 is disposed in a location between the first end 62 and the second end 64, and the maximum thickness H decrements from that location to the first end 62 and the second end 64. The main body 60 is made of an elastic material, such as PU (polyurethane), plastic, rubber, silicone, or foam material, but the present invention is not limited to this. Preferably, relative to the second end 64, the maximum thickness H is located closer to the first end 62. Preferably, the length of the main body 60 is about 40% to 70% of the foot length of the wearer. More preferably, length of main body is about 42% to 55% of the foot length of the wearer. Preferably, the maximum thickness H is about 1% to 20% of the length of the main body. More preferably, the maximum thickness H is about 2% to 5% of the length of the main body. Further, the main body is divided into three portions, which are the first support portion 70, the second support portion 72, and the third support portion 74. The first support portion 70 extends from the first end 62 to the second end 64. The third support portion 74 extends from the second end 64 to the first end 62. The second support portion 72 is a middle portion which connects the first support portion 70 and the third support portion 74. Preferably, length of the first support portion 70 is about 20% to 45% of the length of the main body, length of the second support portion 72 is about 10% to 30% of the length of the main body, and length of the third support portion 74 is about 30% to 55% of the length of the main body. More preferably, length of the first support portion 70 is about 30% to 40% of the length of the main body, while length of the second support portion 72 is about 15% to 25% of the length of the main body, and length of the third support portion 74 is about 35% to 45% of the length of the main body.
Refer to FIG. 5A for a side cross-sectional view of a heeled shoe for which the device of the present invention has been installed. The in-shoe support device 50 is placed in the middle and rear portions of the foot contact surface/insole/bottom plate 102 of a heeled shoe 100, to decrease the downwardly inclined angle of foot contact surface/insole/bottom plate 102 of the heeled shoe 100. The second end 64 is located close to the heel of a heeled shoe 100, while the first end 62 is disposed toward the front of a heeled shoe 100. Subsequently, refer to FIG. 5B for a side cross-sectional view of the foot bone anatomy and a heeled shoe for which the device of the present invention has been installed as shown in FIG. 5A. As shown in FIG. 5B, the second end 64 corresponds to the rearfoot 30 or calcaneus 34, while the position of the maximum thickness H (as shown in FIG. 4B) corresponds to that of user's midfoot 20, in particular to the central region 202 (as shown in FIG. 3B). It is worth to note that, the in-shoe support device 50 is made of an elastic material, so that it can be pressed to match with the curve of the midfoot 20 and rearfoot 30. To be more specific, the third support portion 74 is used to support rearfoot 30 or calcaneus 34, to increase the contact area of the rearfoot 30, so that the rearfoot 30 is able to bear more weight. As such, it can decrease the load on the forefoot 10, also shift the center of mass in the body backward, so that wearer can walk more steadily with heeled shoes. Further, the first support portion 70 and the second support portion 72 support the midfoot 20, especially the central region 202, to increase the contact area of the midfoot 20. As such, weight can be shifted from the forefoot 10 to the midfoot 20, to improve the problem of increased weight on the forefoot 10, and to shift the center of mass in the body backward, so that wearer can walk more steadily with heeled shoes. In a preferred embodiment, the first support portion 70 is used to support the rear portion of the forefoot 10 and the front portion of the midfoot 20. This results in increasing the contact area of the midfoot 20 and then decreasing the pressure on the high load-bearing region 16. (as shown in FIGS. 3A and 3B).
In an embodiment of the present invention, refer to FIGS. 4A and 5B, wherein, the first support portion 70, the second support portion 72, and the third support portion 74 are defined as having the first maximum width, the second maximum width, and the third maximum width respectively. While the third maximum width is greater than the first maximum width and the second maximum width, such that the third support portion 74 is able to a have larger contact area with the rearfoot 30, so the overall weight distribution on the rearfoot 30 can be more even. Preferably, the first maximum width is not greater than the second maximum width. Preferably, the first maximum width and the second maximum width are about 45% to 90% of the third maximum width, such that most or all the regions of the first support portion 70 and the second support portion 72 corresponds to the central region 202 of the midfoot 20, to increase the contact area of the central region 202, in achieving the purpose of supporting the central region 202. More preferably, the first maximum width and the second maximum width are about 50% to 85% of the third maximum width. Preferably, the first maximum width is between 1.5 cm to 5.5 cm. More preferably, the first maximum width is between 2.0 cm to 3.5 cm.
Summing up the above, for the in-shoe support device 50, the design of the thickness distribution and its correspondence to the foot position in heeled shoes can alter the curvature of the foot bed of a heeled shoe. As such, it is able to increase the contact area of midfoot 20 and rearfoot 30 and provide sufficient support for the midfoot 20. Also, it can reduce the tendency of the foot to slide forward in the heeled shoe, creating a backward-shifting of the center of gravity, and creating a better weight-bearing environment for the foot. From the biomechanical viewpoint, this could also reduce the load at the ankle joint and leg muscle.
It is worth to note that, the major characteristics of the in-shoe support device 50 for heeled shoes are the design of the thickness distribution and its correspondence to the foot position in heeled shoes, which can alter the curvature of the foot bed of a heeled shoe. In this respect, the in-shoe support device 50 for heeled shoes can be an independent device formed by a single piece, or it can be integrated with other devices, such as insole, medial arch support pad, or lateral arch support pad, to form an integrated device. Although the in-shoe support device 50 is used mainly for heeled shoes, it can also be used for other kinds of shoes, to increase the contact area for the central region 202 of the midfoot 20 and then improve the uneven foot pressure distribution.
Also, it is worth to note that, as shown in FIGS. 4B and 5B, one of the major characteristics of the in-shoe support device 50 of the present invention is the raised area, which starting from the second end 64 of the third support portion 74 to the maximum thickness H in the second support portion 72. Wherein, as shown in FIG. 5C, in a particular situation, a user wears a heeled shoe 100′ of which the curvature of the foot contact surface/insole/bottom plate 102′ having a significantly downwardly inclined angle relative to the horizontal plane. Under this situation, although the midfoot 20 or the central region 202 may not contact the in-shoe support device 50 (as shown in FIG. 3B), yet the rearfoot 30 can still make an effective contact with the raised area of the in-shoe support device 50. Therefore, it is able to increase the contact area of the rearfoot, create a backward-shifting of the weight, and then improve the problem of excess stress on forefoot 10. In a preferred embodiment, as shown in FIG. 5B, the midfoot 20 and rearfoot 30 make a contact with the raised area and then create a backward-shifting of the weight.
To be more specific, in an exemplified embodiment, refer to FIGS. 6A and 6B respectively for a top view of the distribution of right foot pressure when a user standing with a heeled shoe for which the device of the present invention has not been installed and a-top view of the distribution of right foot pressure when a user standing with a heeled shoe for which the device of the present invention has been installed. As shown in FIG. 6A, the foot pressure is distributed mainly on the forefoot 10, with a center of gravity 300a located at the rear region of the forefoot 10. Further, as shown in FIG. 6B, the foot pressure is distributed more evenly on the forefoot 10 and rearfoot 30, with a center of gravity 300b located on the midfoot 20. By comparing FIG. 6B with FIG. 6A, when a user standing with a heeled shoe with the device of the present invention having been installed, the pressure on the forefoot 10 decreases and the pressure on the rearfoot 30 increases. As such, it is able to improve the problem of excess stress on forefoot 10 and create a backward-shifting of the center of gravity from 300a to 300b.
Further, refer to FIGS. 7A and 7B respectively for a top view of the distribution of right foot pressure when a user walking with a heeled shoe for which the device of the present invention has not been installed and a top view of the distribution of right foot pressure when a user walking with a heeled shoe for which the device of the present invention has been installed. As shown in FIG. 7A, the foot pressure is distributed mainly on the forefoot 10, with a center of gravity 400a located at the middle region of the forefoot 10. Further, as shown in FIG. 7B, the foot pressure is distributed more evenly on the forefoot 10 and rearfoot 30, with a center of gravity 400b located at the rear region of the forefoot 10. By comparing FIG. 7B with FIG. 7A, when a user walking with a heeled shoe for which the device of the present invention has been installed, the pressure on the forefoot 10 decreases and the pressure on the rearfoot 30 increases. In addition, the pressure on the midfoot 20 also increases. As such, it is able to improve the problem of excess stress on the forefoot 10 and create a backward-shifting of the center of gravity from 400a to 400b.
Finally, it is worth to note that, in the descriptions above, 0.1% is utilized as a unit for percentage measurement. By way of example, the length of main body is in a range of 40%, 40.1%, 40.2%, . . . 69.9%, 70% of foot length. Namely, the length of main body is about 40% to 70% of foot length, with 0.1% as spacing for distribution. Similarly, in the present invention, 0.1 cm is used as a unit for width measurement.
The above detailed description of the preferred embodiment is intended to describe more clearly the characteristics and spirit of the present invention. However, the preferred embodiments disclosed above are not intended to be any restrictions to the scope of the present invention. Conversely, its purpose is to include the various changes and equivalent arrangements which are within the scope of the appended claims.
