JP7137814B2 - Mounting device - Google Patents

Description

TECHNICAL FIELD The present invention relates to an attachment device having a member to be attached that is attached and fixed to an object to be attached using screws, and more particularly, it includes a bone fixation plate that is attached and fixed to bone tissue of a human body using tapping screws. It relates to an implant device.

The applicant of the present application has been developing, manufacturing and selling a hard lock nut ("Hard Lock" is a registered trademark of the applicant) that produces a strong locking effect due to eccentric fitting, and has been developing such a hard lock nut. We are developing machines and instruments for various applications by applying the principle of the above. For example, Patent Document 1 below discloses an implant instrument capable of preventing loosening of a tapping screw.

In particular, in FIGS. 5 to 7 of Patent Document 1, tapping is performed by a screw receiver that is pivotably attached to a bone fixation plate so that the tapping screw can be screwed obliquely in accordance with the direction of the fractured surface of the bone. A screw retaining embodiment is disclosed.

Japanese Patent No. 6285600

However, when the tapping screw is screwed into the bone tissue, the screw receiver that receives the tapping screw swings with respect to the bone fixation plate, so there is a problem that the screwing operation of the tapping screw becomes difficult.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a mounting device having a new mounting structure that allows easy screwing of a screw such as a tapping screw, while also providing a powerful locking effect due to eccentric fitting. With the goal.

In order to achieve the above object, the present invention has taken the following technical means.

That is, the mounting device of the present invention includes a screw having a spherical head and a screw shaft to be screwed into an object to be mounted, a member to be mounted and fixed to the object by the screw, and the screw and a locking member that is crowned on the head of the mounting member and screwed to the mounting member.

The member to be attached includes a mounting recess that is open upward and has a female screw on the inner peripheral surface of which the lock member is screwed, and a bottom surface of the mounting recess that includes a lower portion of the head of the screw. and a bearing surface rotatably supported along the spherical surface.

The lock member has a spherical concave surface on the lower surface thereof into which the upper portion of the head of the screw is fitted, and a male screw to be screwed into the female screw on the outer peripheral surface thereof.

By tightening the lock member covering the head portion supported by the seat surface into the mounting recess, the head portion is pressed against the spherical concave surface at a part in the circumferential direction, and The spherical concave surface is eccentric with respect to the head supported on the seat such that the head is pressed against the seat on the diametrically opposite side of the pressure contact portion.

According to the mounting device of the present invention, since the locking member that exerts a locking action by eccentric fitting is mounted on the head of the tapping screw after the screw is screwed in, the screw can be attached to an object such as bone tissue. The operation of screwing into the bone can be easily performed, and the screw can be screwed in accurately according to the state and direction of the fracture surface of the bone.

Any suitable method may be used for eccentrically moving the spherical concave surface with respect to the head supported on the seat surface. It can also be realized by making the axis of the spherical concave surface eccentric with respect to the axis of the male screw. It can also be realized by making the axis of the internal thread eccentric with respect to the axis of the surface.

1 is a cross-sectional view of an attached state of a surgical implant instrument (attachment device) according to a first embodiment of the present invention; FIG. FIG. 4 is a cross-sectional view of an attached state of a surgical implant instrument (attachment device) according to a second embodiment of the present invention;

Preferred embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a surgical implant instrument as an attachment device according to a first embodiment of the present invention, which comprises a tapping screw 2 screwed into a bone tissue 1 of a human body and a screw 2 that taps the bone tissue. 1 and a fixing cap 4 (locking member) for fixing the tapping screw 2 to the plate 3 .

The tapping screw 2 is made of a metal such as a titanium alloy, and includes a screw shaft portion 22 having a screw thread on the outer peripheral surface and a head portion 21 integrally provided at the upper end (base end) of the screw shaft portion 22. I have. The length of the screw shaft portion 22 may be appropriate according to the size and location of the bone tissue to be screwed, but is usually about several centimeters. In the illustrated example, no screw thread is provided in the vicinity of the base end of the screw shaft portion 22, and the screw thread is formed from the axially intermediate portion to the tip portion. A tapping groove for tapping is formed at the tip of the screw shaft portion 22 . Head 21 is spherical. The head 21 does not have to be a perfect sphere, and may be formed in any suitable part within the range where the pressure contact force indicated by the arrow can act when the tapping screw 2 is screwed obliquely as shown in FIG. 1(a) or (c). A notch, recess, or the like may be provided in the . A tool engaging portion capable of engaging a rotating tool such as a screwdriver is provided at the upper end of the head 21 . The shape of the tool engaging portion may be appropriate.

The plate 3 is made of a metal such as a titanium alloy, and has a thickness of several millimeters. A mounting recess 31 opening upward is provided at an appropriate portion on the upper surface side of the plate 3 . The diameter of the mounting recess 31 is larger than the diameter of the screw head 21 . A female screw to which the fixing cap 4 is screwed is provided on the inner peripheral surface of the mounting recess 31 . The pitch of the female screw may be larger, smaller, or the same as the pitch of the thread on the outer periphery of the screw shaft portion 22 . The depth of the mounting recess 31 is smaller than the plate thickness of the plate 3 .

The bottom of the mounting recess 31 is provided with a spherical bearing surface 32 that supports the lower portion of the screw head 21 so as to be rotatable along its spherical surface. The seat surface 32 has an annular shape in plan view, and an insertion hole through which the screw shaft portion 22 is inserted is formed in the central portion thereof. The diameter of the insertion hole at the lower end of the seat surface 32 is smaller than the diameter of the screw head 21 and larger than the maximum diameter portion of the screw shaft 22 . The maximum diameter portion of the screw shaft portion 22 may be the diameter of the base end portion of the screw shaft portion 22 or the maximum diameter portion of the screw thread.

In this embodiment, the axial center of the female thread of the mounting recess 31 and the axial center of the seat surface 32 are concentric.

The fixing cap 4 is a generally hemispherical member in this embodiment, and has a spherical concave surface 41 on the lower surface thereof into which the upper portion of the screw head 21 is fitted. This spherical concave surface 41 has a hemispherical shape, and the diameter of the hemispherical surface is slightly larger than that of the screw head 21 . Also, the cap 4 has an outer peripheral surface provided with a male screw that is screwed into the female screw of the mounting recess 31 . This male screw is provided from the lower end of the cap 4 to the axially intermediate portion. In this embodiment, the axial center of the spherical concave surface 41 is slightly eccentric with respect to the axial center of the male screw on the outer peripheral surface of the cap 4 by the amount of eccentricity a. Due to such eccentricity, the thickness d1 of the male threaded portion of the cap 4 on the eccentric side of the spherical concave surface 41 is smaller than the thickness d2 of the male threaded portion of the cap 4 on the opposite side in the eccentric direction.

Also, the thickness d2 of the male thread forming portion of the cap 4 on the opposite side in the eccentric direction is equivalent to the gap between the outer peripheral surface of the screw head 21 supported by the seat surface 32 and the inner peripheral surface of the mounting recess 31. or slightly larger. On the other hand, the thickness d1 of the male thread forming portion of the cap 4 on the eccentric side is smaller than the gap between the outer peripheral surface of the screw head 21 supported by the seat surface 32 and the inner peripheral surface of the mounting recess 31 . With such a configuration, by tightening the cap 4 covering the screw head 21 supported by the seat surface 32 into the mounting recess 31, the screw head 21 is partially removed in the circumferential direction on the opposite side of the eccentric direction. While being pressed against the spherical concave surface 41, the screw head 21 is pressed against the bearing surface 32 on the opposite side in the diametrical direction to the pressed portion.

In the illustrated embodiment, the upper end of the cap 4 is provided with a tool engaging portion for engagement with a rotating tool such as a screwdriver, and the cap 4 is configured to cover the screw head 21 as a whole. The lock member of the present invention is not limited to the cap 4 having such a structure, and the upper portion of the cap 4 may be opened.

According to this embodiment, the screw head 21 is formed in a spherical shape, and the plate 3 is provided with the spherical bearing surface 32 for rotatably supporting the screw head 21. Therefore, when the tapping screw 2 is screwed in, There are no members other than the bone fixing plate 3 and the tapping screw 2, and the tapping screw 2 can be easily and accurately screwed into the bone tissue 1. - 特許庁Further, as shown in FIGS. 1(a) to 1(c), even if the tapping screw 2 is screwed obliquely into the bone tissue 1 according to the fracture surface of the bone, the head of the tapping screw 2 can be stably seated. It can be supported on surface 32 . Although the illustrated example shows an example in which the axial center of the screw shaft portion 22 can be tilted within a range of 30° with respect to the central axis, the maximum tilt angle can be appropriately designed.

Furthermore, after the tapping screw 2 is completely screwed in, the screw head 21 supported by the seat surface 32 is covered with the cap 4, and the cap 4 is screwed into the mounting recess 31, whereby the eccentric fit is achieved. A powerful locking action can be produced in the tapping screw 2 .

FIG. 2 shows a surgical implant instrument according to a second embodiment of the present invention. Components similar to those of the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. explain.

In this embodiment, the axial center of the spherical concave surface 41 and the axial center of the male screw on the outer peripheral surface of the cap 4 are concentric. Therefore, the thickness of the externally threaded portion of the cap 4 is the same over the entire circumference. On the other hand, in this embodiment, the axis of the inner peripheral surface of the mounting recess 31 (the axis of the female screw) is slightly eccentric with respect to the axis of the seat surface 32 by the amount of eccentricity a. The clearance between the inner peripheral surface of the mounting recess 31 on the eccentric side of the screw and the outer peripheral surface of the screw head 21 supported by the seat surface 32 is the inner peripheral surface of the mounting recess 31 on the opposite side of the female screw in the eccentric direction. and the outer peripheral surface of the screw head 21 supported by the seat surface 32. The thickness of the male thread forming part of the cap 4 is the gap between the inner peripheral surface of the mounting recess 31 on the side opposite to the eccentric direction of the female thread and the outer peripheral surface of the screw head 21 supported by the bearing surface 32. Equal or slightly larger. Further, in this embodiment, the screw shaft portion 22 has a conical shape whose diameter becomes smaller toward the distal end side. A screw thread is formed over the entire length of the screw shaft portion 22 . Moreover, the tool engaging portion of the cap 4 is configured by a vertically penetrating hexagonal hole so that a hexagonal wrench can be engaged therewith.

According to the present embodiment, when the cap 4 is screwed into the mounting recess 31, the portion in the circumferential direction of the outer peripheral surface of the cap 4 that is pressed by the cap 4 is constant (the left end portion in FIG. 2). It is possible to prevent the screw head 21 from dancing when the cap 4 is screwed.

The present invention is not limited to the above embodiments, and can be modified in design as appropriate. For example, in the above-described embodiments, the present invention is applied to an implant device, but it can be applied to various attachment devices for screwing an appropriate member to be attached to an object to be attached. Further, although the anti-loosening of tapping screws has been exemplified, it can be applied to anti-loosening structures for various screws other than tapping screws.

Claims (4)

A screw having a spherical head and a screw shaft screwed into an object to be mounted, a member to be mounted and fixed to the object by means of the screw, and a head of the screw being crowned A lock member screwed to the attached member,
The member to be attached includes a mounting recess opening upward and having a female screw on the inner peripheral surface thereof to which the locking member is screwed, and a bottom portion of the mounting recess provided at the bottom of the mounting recess and below the head of the screw. and a bearing surface rotatably supported along the spherical surface,
The lock member is provided with a spherical concave surface in which the upper part of the head of the screw is fitted on the lower surface thereof, and is provided with a male screw to be screwed into the female screw on the outer peripheral surface thereof,
By tightening the lock member crowned over the head supported by the seat surface into the mounting recess, the head is pressed against the spherical concave surface at a part in the circumferential direction, and the pressure contact portion is pressed. The spherical concave surface is eccentric with respect to the head supported on the seat surface such that the head is pressed against the seat surface on the diametrically opposite side to the pressure contact portion. A mounting device having a gap between said head and said spherically concave surface on diametrically opposite sides . The mounting device of claim 1, wherein
The axial center of the seat surface and the axial center of the female screw are concentric, and the axial center of the spherical concave surface is eccentric with respect to the axial center of the male screw. mounting device, wherein said spherically concave surface is eccentric with respect to a portion. The mounting device of claim 1, wherein
The shaft center of the spherical concave surface and the shaft center of the male screw are concentric, and the shaft center of the female screw is eccentric with respect to the shaft center of the seat surface, so that the head supported on the seat surface. mounting device, wherein said spherically concave surface is eccentric with respect to a portion. 4. The attachment device according to claim 1, 2 or 3, wherein said attachment object is bone tissue of a human body and said attachment device is an implant device.

Images