Patent Application
20140283416
The present invention relates to a heel fixing structure for fastening a heel to a woman's shoe such as a high-heeled shoe.
According to a conventional woman's high-heeled shoe as illustrated in
A large nail 4a such as a helical nail is driven along the central axis of the heel 3 from the top surface of the insole 2 for rigidly fastening the heel 3 to the insole 2. In addition, short thin nails 4b are driven around the large nail 4a to reinforce the large nail 4a and prevent rotation of the heel 3.
The insole 2 generally consists of multiple layers and a narrow metal shank lying between two central layers for the reinforcement and resiliency of the insole 2. The large nail 4a and the thin nails 4b thus must be driven substantially along the central axis of the heel 3 so as to avoid the contact with the shank in the insole 2 and the metal pipe 5 inside the heel 3. This requires highly accurate positioning of the nails.
Even slight misalignment in the position or angle of these nails results in a defective shoe having the large nail 4a and the thin nails 4b appearing from the heel 3, as illustrated in
To solve such a problem, Patent Literatures 1 and 2 disclose techniques of fastening a heel to an insole without nails. These techniques enable fastening of a heel without driving nails and therefore can reduce the number of defective shoes.
That is to say, according to the techniques in Patent Literatures 1 and 2, a self-tapping screw 7 is forcedly screwed into a metal pipe 8 inside the heel 3 while tapping the inner surface of the metal pipe 8 to fasten the heel 3 to the insole 2, as illustrated in
The techniques in Patent Literatures 1 and 2 ensure fastening of the heel 3 to the insole 2 with the self-tapping screw 7. In general, a pin heel 3 having an edge with a diameter of 10 mm or smaller, for example, can accept only a thin metal pipe 8. Unfortunately, a thin self-tapping screw 7 fittable within such a thin metal pipe 8 cannot provide sufficient fastening strength.
Moreover, screwing of the self-tapping screw 7 into the metal pipe 8, which involves tapping or threading of the metal pipe 8, cannot be readily achieved by manual operation and requires mechanical devices for tapping and threading. Additionally, during the tapping, the metal pipe 8 may cause relative rotation or detachment to/from the heel 3.
An object of the present invention, which has been accomplished to solve the above problems, is to provide a heel fixing structure for a woman's shoe that enables easy and rigid fastening of a heel to an insole.
To achieve the above object, a heel fixing structure to an insole for a woman's shoe according to the present invention includes:
a heel;
a metal reinforcing shaft including a thin lower portion and a thick upper portion having a larger external diameter than the external diameter of the thin portion, the thick portion including a first thread groove on the inner surface, the reinforcing shaft being embedded in the heel in the longitudinal direction of the heel; and
a fastening bolt screwed through the insole into the first thread groove to fasten the heel to the insole.
The heel fixing structure for a woman's shoe according to the present invention can achieve simple, rigid, and secure fastening by screwing of a thick fastening bolt. This structure can therefore significantly reduce the number of defective shoes due to failure of nailing, and is applicable to a pin-heel shoe.
The present invention will now be described in detail based on embodiments illustrated in
During injection molding of the heel 13, the reinforcing shaft 14 is embedded in the heel 13 such that the thin portion 14a which extends along the heel 13 in the longitudinal direction of the heel 13 does not appear from the bottom of the heel 13 and such that the thick portion 14b does not protrude from the top of the heel 13.
As illustrated in
The heel 13 is temporarily fixed to the insole 12 by means such as adhesion before screwing of the fastening bolt 15 into the reinforcing shaft 14. The fastening bolt 15 is screwed through the washer 16 and the opening 12d of the insole 12 into the thread groove 14c with a cross-slot screwdriver applied to the cross slot on the head 15a of the fastening bolt 15 such that the heel 13 is fixed to the insole 12 with the head 15a and the washer 16. In particular, the washer 16 engaging with a part of the shank 12c via the upper layer 12b further reinforces the fastening.
Furthermore, one or several optional thin nails 19 may be driven around the fastening bolt 15 so as to avoid the shank 12c. This prevents accidental relative rotation of the heel 13 to the insole 12 during the use. The protrusions 14d prevent relative rotation and detachment of the reinforcing shaft 14 to/from the heel 13 during screwing of the fastening bolt 15 into the thick portion 14b. Additionally, the bottom-end of the thin portion 14a is provided with a heel-tip accessory 20 made of a material such as rubber and having a convex 20a fittable within the thin portion 14a.
Thus, in Embodiment 1, the fastening bolt 15, which completely functions a substitute for a conventional large nail 4a and a small number of thin nails 19, can significantly reduce the number of defective shoes caused by failure of nailing.
According to Embodiment 1, the reinforcing shaft 14 includes the thin portion 14a with a small external diameter and the thick portion 14b with a large external diameter thereabove. This enables, even in a pin-heel shoe, embedding of the reinforcing shaft 14 in the heel 13, and screwing of the thick fastening bolt 15 into the thick portion 14b, thereby achieving rigid fastening. In particular, the thickness difference in the reinforcing shaft 14 between the thin portion 14a and the thick portion 14b prevents downward shift of the reinforcing shaft 14 in the heel 13 caused by a load from the above during screwing of the fastening bolt 15 or during the use of the shoe.
Although the reinforcing shaft 14 according to Embodiment 1 includes the thin portion 14a and the thick portion 14b that are welded together, the thin portion 14a having an upper-external thread ridge may be screwed into the thread groove 14c of the thick portion 14b. Alternatively, the thin portion 14a may be connected to the thick portion 14b by swaging or adhesion, for example.
Also, the reinforcing shaft 14 may have tapered thick portion 14b connected to the thin portion 14a as illustrated in
The cross sections of the thin portion 14a and the thick portion 14b are not limited to a circle, and may be a polygon or an ellipse, for example. In particular, the thick portion 14b having a polygonal shape prevents relative rotation to the heel 13 during screwing of the fastening bolt 15. Additionally, the thin portion 14a is not limited to a pipe and may be a solid shaft with a hole provided at the bottom-end for receiving the heel-tip accessory 20.
Any countermeasure is required to prevent scratch on the user's sole by the head 15a of the screwed fastening bolt 15 which is not parallel with the top surface of the insole 12. One solution to the problem is to provide a fastening bolt 15′ with an inclined head 15a illustrated in
According to the above-described Embodiment 1, the reinforcing shaft 14 is embedded in the heel 13 by the injection molding of the heel 13.
In contrast, according to Embodiment 2, a reinforcing shaft 22 including a thin portion 22a connected to a thick portion 22b is driven into a hole 21a of a heel 21, as illustrated in
The thick portion 22b may have anti-rotational means such as blades disposed on its outer surface in the longitudinal direction to prevent the rotation of the reinforcing shaft 22 during the screwing of the fastening bolt 15. Also, the reinforcing shaft 22 may have a shape as illustrated in
As described above, the heel 21 including the reinforcing shaft 22 driven into the heel 21 is attached to the insole 12, and then the fastening bolt 15 or 15′ is screwed into a thread groove 22c of the thick portion 22b in the same manner as Embodiment 1. This enables rigid fastening of the heel 21 to the insole 12.
Embodiment 2 is especially effective for the heel 21 made of wood.
In contrast, a metal reinforcing shaft 31 according to Embodiment 3 formed through a technique such as casting to be embedded in the synthetic-resin heel 13 has the fastening bolt 15 and a thin portion 31a which are attached to the reinforcing shaft 31 in different directions in a thick portion 31b. In more specific, the thick portion 31b, which is connected to the thin portion 31a to form the reinforcing shaft 31, includes a thread groove 31c for receiving the fastening bolt 15 such that the top surface of the head 15a is parallel with the top surface of the insole 12, and a thread groove 31d for receiving the thin portion 31a such that the thin portion 31a extends along the heel 13 in the longitudinal direction of the heel 13. The thin portion 31a may be connected to the thick portion 31b by a technique such as welding or adhesion.
Since the top surface of the head 15a of the fastening bolt 15 screwed into the thick portion 31b is parallel with the top surface of the insole 12, scratching on the user's sole by the head 15a can be prevented.
Such a structure having the two bolts 15 and 32 screwed into the reinforcing shaft 14 further reinforces the fastening of the insole 12.
The present invention is applicable to not only high-heeled shoes but also middle-heeled shoes and low-heeled shoes.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2011-238803 | Oct 2011 | JP | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/JP2012/078040 | 10/30/2012 | WO | 00 | 4/11/2014 |
