JP7254158B1 - drill stopper - Google Patents

Abstract

A drill stopper having high versatility and capable of being fixed at an arbitrary position on a drill shaft is provided. A drill stopper (1) includes a body (2) having a through hole (2a) through which a drill shaft penetrates, a pressing member (6) provided in the body (2) and forming a part of the inner surface of the through hole (2a), and a body (2) extending through the through hole (2a). and a lever 3 for locking and unlocking the drill shaft inside. The pressing member 6 can be displaced in a direction toward the center axis O of the through hole 2a. The lever 3 is arranged on the side opposite to the central axis O with respect to the pressing member 6, and is between a fixed position in which the pressing member 6 is pressed in a direction toward the central axis O and a release position in which the pressing member 6 is released. is supported by the body 2 so as to be rotatable around a predetermined rotation axis. [Selection drawing] Fig. 2

Description

The present invention relates to drill stoppers.

Conventionally, there is known a drill stopper attached to a surgical drill for drilling a bone (see, for example, Patent Documents 1 and 2).
As shown in FIG. 12, for bicortical fixation of the screw 20 to a tubular bone A, such as the tibia, through holes are drilled in both the proximal and contralateral cortical bones D1, D2. FIG. 12 shows an open wedge high tibial osteotomy (OWHTO) in which a bone plate 21 is fixed to the medial surface of the tibia A with screws 20 . Bicortical is a fixation method in which screws 20 are passed through cortical bones D1 and D2 on both the front side and the contralateral side. With this method, the screw 20 is fixed to the hard cortical bone at two points, so that the screw 20 can be fixed to the bone A with high fixing strength.

On the other side of the bone A there may be tissue such as nerves B and blood vessels C. The drill stoppers of Patent Documents 1 and 2 are for preventing the tip of the drill shaft from excessively protruding from the contralateral cortical bone D2, and the drill is stopped immediately after the tip of the drill shaft penetrates the contralateral cortical bone D2. is configured to stop the progress of

JP 2014-128313 A JP 2013-154138 A

The drill stopper of Patent Document 1 can be attached only to a collet chuck type electric drill. Therefore, the drill stopper of Patent Literature 1 cannot be used for electric drills that employ other types of chucks such as Hudson chucks, resulting in a lack of versatility.
The drill stopper of Patent Document 2 has a telescope structure having an inner cylinder and an outer cylinder, and the position of the tip of the outer cylinder that abuts the surface of the front side cortical bone D1 can be changed in the longitudinal direction of the drill shaft. . The outer tubular portion is positioned with respect to the inner tubular portion by engaging a connecting engagement piece provided on the outer tubular portion with one of a plurality of connecting grooves provided on the inner tubular portion. That is, the position of the tip of the outer cylinder is restricted by the position of the connecting groove, and the tip of the outer cylinder cannot be fixed at a free position.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a drill stopper that is highly versatile and that can be fixed at any position on a drill shaft.

One aspect of the present invention is a drill stopper attached to a drill shaft of a surgical drill for drilling a bone, comprising a body having a through hole through which the drill shaft passes; A pressing member forming a part of the inner surface and a lever for fixing and releasing the body to and from the drill shaft in the through hole, the pressing member being displaceable in a direction toward the central axis of the through hole. wherein the lever is arranged on the side opposite to the center axis with respect to the pressing member and pushes the pressing member in the direction toward the center axis. The drill stopper is supported by the body so as to be rotatable about a predetermined rotation axis between a fixed position where the holding member is displaced by pressing and a fixed release position where the holding member is released.

It is a side view which shows the usage condition of the drill stopper which concerns on one Embodiment. 2 is an exploded perspective view of the drill stopper of FIG. 1; FIG. FIG. 2 is a vertical cross-sectional view for explaining the action of the drill stopper of FIG. 1, and shows a state in which the lever is arranged at the open position; FIG. 2 is a vertical cross-sectional view for explaining the action of the drill stopper of FIG. 1, and shows a state in which the lever is arranged at the closed position; FIG. 2 is a vertical cross-sectional view for explaining the action of the drill stopper of FIG. 1, showing a state where the drill shaft is arranged in the through hole and the lever is arranged at the closed position; FIG. 4 is a side view of the tip of a cam lever provided with a cam surface; It is a figure explaining the usage method of the butting part of a lever. 1. It is a figure explaining the procedure which uses the drill with which the drill stopper of FIG. 1 was attached, and makes a hole in a bone. FIG. 2 is a front view for explaining the position of the center of gravity of the drill stopper in FIG. 1; FIG. 11 is a side view showing a usage state of a drill stopper according to another embodiment; < Figure 8 >It is the front view of the drill stopper, the figure which shows the state where the lever is arranged in open position. Fig. 9 is a front view of the drill stop of Fig. 8 with the lever positioned in the closed position; FIG. 10 is a perspective view of the drill stopper showing a modified example of the abutting portion, showing a state in which the lever is arranged at the open position; 10B is a perspective view of the drill stop of FIG. 10A with the lever positioned in the closed position; FIG. FIG. 10B is a side view for explaining how to use the abutting portion of FIGS. 10A and 10B; FIG. 10 is a side view of the drill stopper showing another modified example of the abutting portion, and is a diagram for explaining how to use the abutting portion. FIG. 10 is a diagram showing a state in which the body is in contact with another member due to compression of the elastic member; 11B is an exploded perspective view of the drill stop of FIGS. 11A and 11B; FIG. It is a figure explaining OWHTO.

A drill stopper according to one embodiment of the present invention will be described below with reference to the drawings.
As shown in FIG. 1, a drill stopper 1 according to this embodiment is attached to the side surface of a drill shaft 10 of a surgical drill for drilling a hole in a bone, and limits the amount of insertion of the drill shaft 10 into the bone. be. In particular, the drill stop 1 is used when drilling pilot holes in the bone for screws that are bicortically fixed to the bone.

For example, in the open medial high tibial osteotomy (OWHTO) shown in FIG. It is fixed to the tibia A with a tikal. A nerve B and an artery C are present on the extension of the screw 20, and the distance from the outer surface of the contralateral cortical bone D2 to the nerve B and the artery C is about 10 mm to 20 mm. Therefore, it is preferable that the amount of protrusion of the tip of the drill shaft 10 from the outer surface of the contralateral cortical bone D2 is controlled to 2 mm to 3 mm.

As shown in FIGS. 1 and 2, the drill stopper 1 includes a body 2 having a through hole 2a through which a drill shaft 10 extends, and a lever 3 for fixing and unlocking the body 2 to and from the drill shaft 10 in the through hole 2a. and a pin 4 connecting the lever 3 to the body 2.
Body 2, lever 3 and pin 4 are formed from a biocompatible and strong metallic material such as stainless steel.

As shown in FIGS. 2 to 3C, the body 2 includes a main portion 5 constituting a main portion of the body 2, an upper plate (pressing member) 6 and a lower plate (adjusting member) 7 supported by the main portion 5. and In one example, main section 5 and plates 6, 7 are molded as a single seamless piece. 3A to 3C are longitudinal sectional views of the drill stopper 1 cut along a plane including the center axis O of the through hole 2a and perpendicular to the rotation axis P of the lever 3. FIG.

The main portion 5 is a substantially partially cylindrical member having a portion cut in the longitudinal direction in the circumferential direction, and the lever 3 is a strip-shaped member arranged in the cut portion of the main portion 5 . . Pin holes 5a and 3a communicating with each other in a direction perpendicular to the central axis O are formed at the tip of the main portion 5 and the tip of the lever 3, respectively. A tip portion of the lever 3 is connected to a tip portion of the body 2 so as to be rotatable about a predetermined rotation axis P by a pin 4 inserted into the pin holes 5a, 3a. A rotation axis P is the center axis of the pin 4 . Both ends of the pin 4 are fixed to the main part 5, for example by welding.

Hereinafter, the direction parallel to the central axis O is the longitudinal direction of the drill stopper 1, the direction parallel to the rotation axis P is the lateral direction of the drill stopper 1, and the direction orthogonal to both the central axis O and the rotation axis P is the direction of the drill stopper 1. Define the vertical direction. The lever 3 is arranged above the through hole 2a.

The upper plate 6 and the lower plate 7 are thin plate-like members extending parallel to the central axis O, and face each other in the vertical direction with the central axis O interposed therebetween. The upper plate 6 is arranged above the through hole 2a, and the lower plate 7 is arranged below the through hole 2a. The plates 6, 7 are arranged inside the main portion 5, and the inner surfaces 6a, 7a of the plates 6, 7 on the side of the central axis O each define a part of the through hole 2a. That is, the inner surface 6a forms part of the cylindrical inner surface of the through hole 2a, and the inner surface 7a forms another part of the cylindrical inner surface of the through hole 2a.

The upper plate 6 is supported by the main portion 5 so as to be elastically displaceable at least downward, that is, in a direction toward the central axis O. As shown in FIG. The lower plate 7 is supported by the main portion 5 so as to be elastically displaceable at least downward, that is, in a direction away from the central axis O. As shown in FIG.
Specifically, the base ends of the plates 6 and 7 are fixed to the main portion 5, and the plates 6 and 7 are supported by the main portion 5 in a cantilever manner. The tip of each plate 6, 7 is a free end that can be displaced in the vertical direction. Due to the deflection of the plates 6 and 7 formed of thin plates, the tip portions of the plates 6 and 7 are elastically displaced in the vertical direction.

The lever 3 is arranged on the side opposite to the central axis O with respect to the upper plate 6 , that is, on the upper side of the upper plate 6 , and can be opened and closed with respect to the body 2 by rotating around the rotation axis P. Specifically, the lever 3 is rotatable about the rotation axis P between the open position (fixed position) shown in FIG. 3A and the closed position (fixed position) shown in FIGS. 3B and 3C. .

The closed position is the position where the lever 3 pushes the upper plate 6 downward, thereby fixing the body 2 to the drill shaft 10 in the through hole 2a. Specifically, the upper plate 6 pressed by the lever 3 is bent and displaced downward, and as shown in FIG. 3C, the inner surface 6a is pressed against the side surface of the drill shaft 10 in the through hole 2a. . Thereby, the drill stopper 1 is fixed to the drill shaft 10 by friction between the inner surface 6 a and the side surface of the drill shaft 10 .
The open position is the position in which the lever 3 releases the top plate 6 and thereby releases the fixation of the body 2 to the drill shaft 10 . Specifically, the upper plate 6 released from the pressure is displaced upward by an elastic restoring force, thereby releasing the fixation of the drill stopper 1 to the drill shaft 10 .

Here, as shown in FIG. 3C , the pressing force applied from the lever 3 to the upper plate 6 is also applied to the lower plate 7 via the drill shaft 10 . Therefore, similarly to the upper plate 6, the lower plate 7 is also displaced downward by bending. Due to this displacement of the lower plate 7, the force required to rotate the lever 3 to the closed position is adjusted within a certain range regardless of variations in the diameter of the drill shaft 10, as will be described later.

In this embodiment, the lever 3 is a cam lever having a cam surface 3b at its tip connected to the body 2 . The cam surface 3b is a convex surface curved around the rotation axis P, which is composed of a tip surface, a lower surface, and an upper surface of the tip portion of the lever 3. As shown in FIG. The cam surface 3b is either in light contact with the top plate 6 when the lever 3 is placed in the open position, or slightly away from the top plate 6 and contacts the top plate 6 upon rotation of the lever 3 to the closed position. It rotates around the rotation axis P while doing so. The distance from the rotation axis P to the contact point of the cam surface 3b with the top plate 6 gradually increases as the lever 3 rotates from the open position to the closed position. Therefore, as the lever 3 approaches the closed position, the pressing force applied by the cam surface 3b to the upper plate 6 gradually increases. When the lever 3 is located at the closed position, the friction between the cam surface 3b and the upper plate 6 prevents the lever 3 from rotating in the opening direction, and the lever 3 is stably fixed at the closed position.

FIG. 4 shows an example of a preferred design of the cam surface 3b. The cam surface 3b curves in an arc shape or a substantially arc shape around a center axis Q parallel to the rotation axis P. As shown in FIG. At the closed position, the center axis Q of the cam surface 3b is eccentric downward with respect to the rotation axis P. As shown in FIG. Therefore, in FIG. 4, the distance rb is greater than the distance ra, and the distance from the rotation axis P to the cam surface 3b gradually increases from the point α to the point β. The point α is the lowest end of the cam surface 3b at the open position, and the point β is the lowest end of the cam surface 3b at the closed position.

The diameter of the through-hole 2a is slightly larger than the diameter of the drill shaft 10 when the plates 6 and 7 are not pressed by the lever 3 . For example, the diameter of the drill shaft 10 is designed to be 4.9 mm, and the diameter of the through hole 2a is designed to be 5.0 mm. However, the diameter of the drill shaft 10 has variations due to dimensional tolerances. By providing the lower plate 7 , the drill stopper 1 can accommodate variations in the diameter of the drill shaft 10 .

That is, when the lower plate 7 is not provided, when the diameter of the drill shaft 10 is larger than the standard value, the resistance against rotation of the cam lever 3 to the closed position increases, and the cam lever 3 cannot be rotated to the closed position. It may become difficult and the sides of the drill shaft 10 may be deformed. When the lower plate 7 is provided, the lower plate 7 is displaced according to the magnitude of the pressing force applied from the cam lever 3 to the upper plate 6, so that even when the diameter of the drill shaft 10 is larger than the standard value, the drill can be The cam lever 3 can be rotated to the closed position with substantially the same force as when the diameter of the shaft 10 is below the standard value.
The cam surface 3b is preferably designed so that the lower plate 7 is always flexed and displaced when the diameter of the drill shaft 10 is within dimensional tolerances.

The lever 3 further has an abutting portion 3c that abuts another member attached to the drill shaft 10 in a direction along the central axis O. As shown in FIG. As shown in FIG. 5, when the lever 3 is in the open position, the abutting portion 3c faces the front end surface of the body 2 in the front-rear direction and is separated from the body 2 in the front-rear direction by a predetermined distance L. position and facing away from the body 2. Therefore, the distance between the member 12 and the body 2 can be adjusted to a predetermined distance L by abutting the abutting portion 3c against the base end surface of the other member 12 while the lever 3 is placed at the open position. can.

In one example, the upper surface 3d of the lever 3 is provided with a protrusion 3e that protrudes from the upper surface 3d. The abutting portion 3c is formed from the side surface of the convex portion 3e on the base end side of the lever 3. As shown in FIG. The upper surface 3d of the lever 3 is arranged on the upper side when the lever 3 is arranged at the closed position. The angle formed by the upper surface 3d and the abutting portion 3c is preferably 90° or an angle close to 90°. In this case, the distance between the member 12 and the body 2 is adjusted by abutting the corner between the upper surface 3d and the abutting portion 3c with the corner between the side surface and the base end surface of the member 12. As shown in FIG.
The interval L is designed according to the thickness of the contralateral cortical bone D2 and the predetermined protrusion amount of the tip of the drill shaft 10 from the outer surface of the contralateral cortical bone D2. In one example, if the standard thickness of the cortical bone D2 is about 5 mm and the predetermined amount of protrusion is about 2 mm to 3 mm, the distance L is designed to be 8 mm.

Next, a method of drilling a bone using a drill to which the drill stopper 1 is attached will be described with reference to FIG.
FIG. 6 shows a step of drilling pilot holes in the bone A for bicortical fixing of the screws 20 to the bone A in an operation for fixing the bone plate 21 to the outer surface of the bone A with the screws 20 . Bone A is a tubular bone such as a tibia or a femur, and soft cancellous bone E on the inside is covered by hard cortical bone D on the outside. A tubular drill guide 11 for guiding the drill shaft 10 is attached to the bone plate 21 .

First, in step S<b>1 , the operator fixes the drill stopper 1 to the proximal end of the drill shaft 10 and attaches the C ring 12 to a desired position between the distal end of the drill shaft 10 and the drill stopper 1 . The C-ring 12 is fixed to the drill shaft 10 by friction between the inner surface of the C-ring 12 and the side surface of the drill shaft 10 and is movable in the longitudinal direction of the drill shaft 10 against the friction. The C-ring 12 is used to grasp the amount of insertion of the drill shaft 10 into the bone A from the distance between the proximal end of the drill guide 11 and the C-ring 12, and to measure the distance between the proximal end surface of the drill guide 11 and the drill stopper 1. Used for keeping distance.

Next, in step S2, the operator operates the electric drill 13 to rotate the drill shaft 10, and the rotating drill shaft 10 moves the bone A from the outer surface of the front cortical bone D1 to the inner surface of the contralateral cortical bone D2. make a hole in After the C-ring 12 abuts against the proximal end face of the drill guide 11 while the bone A is being drilled, the drill shaft 10 moves relative to the C-ring 12 . The operator temporarily stops the rotation and advancement of the drill shaft 10 when the tip of the drill shaft 10 contacts the inner surface of the contralateral cortical bone D2. When the tip of the drill shaft 10 comes into contact with the inner surface of the contralateral cortical bone D2, the resistance to advancement of the drill shaft 10 increases sharply. It can be recognized that the tip of the drill shaft 10 is in contact with the inner surface of the contralateral cortical bone D2.

Next, in step S3, the operator releases the fixation of the drill stopper 1 to the drill shaft 10 by rotating the lever 3 to the open position. Next, after confirming that the C ring 12 is in contact with the base end surface of the drill guide 11, the operator moves the drill stopper 1 toward the C ring 12 side with respect to the drill shaft 10 so that the contact portion 3c is The drill stopper 1 is fixed to the drill shaft 10 again by positioning the drill stopper 1 at a position where it abuts against the base end face of the C ring 12 and rotating the lever 3 to the closed position.
Next, in step S<b>4 , the operator resumes rotating and advancing the drill shaft 10 and advances the drill shaft 10 until the distal end surface of the body 2 contacts the proximal end surface of the C ring 12 . The operator stops rotating and advancing the drill shaft 10 when the distal end surface of the body 2 contacts the proximal end surface of the C-ring 12, and completes drilling.

Note that the C ring 12 is attached to the drill shaft 10 as required, and does not necessarily have to be used. When the C ring 12 is not used, the drill stopper 1 is positioned at a position where the abutting portion 3c abuts the proximal end surface of the drill guide 11 in step S3, and the distal end surface of the body 2 is aligned with the proximal end surface of the drill guide 11 in step S4. advance the drill shaft 10 until it contacts the

As described above, according to this embodiment, when the amount of protrusion of the tip of the drill shaft 10 from the outer surface of the contralateral cortical bone D2 reaches a predetermined amount, the tip surface of the body 2 is positioned at the base of the C ring 12. Hit the edge. As a result, the advancement of the drill shaft 10 is mechanically blocked, and the operator can recognize that the tip of the drill shaft 10 has protruded by a predetermined amount from the outer surface of the contralateral cortical bone D2. Therefore, excessive perforation of the bone A can be prevented.

Also, according to this embodiment, the drill stopper 1 is fixed directly to the side surface of the drill shaft 10 by friction between the plates 6 , 7 and the drill shaft 10 . Therefore, the drill stopper 1 can be used for various types of drills regardless of the type of chuck of the electric drill 13, and regardless of whether it is electric or manual, and it is possible to provide a highly versatile drill stopper 1. can. In addition, since there is no restriction on the mounting position of the drill stopper 1 on the drill shaft 10, the mounting position can be changed steplessly in the longitudinal direction of the drill shaft 10, and the drill stopper 1 can be placed at any position on the drill shaft 10. can be installed.

Further, according to the present embodiment, fixing and unlocking of the drill stopper 1 to the drill shaft 10 are performed only by rotating the cam lever 3 . Further, the cam lever 3 can be rotated with a small force, and a large fixing force of the body 2 to the drill shaft 10 can be obtained. Therefore, the operator can rotate the cam lever 3 using only the thumb of one hand, for example, and can easily perform the operation of fixing and unlocking the drill stopper 1 .
In one design example, when the diameter of the drill shaft 10 is 4.85 mm to 4.90 mm, the diameter of the through hole 2a is 5.0 mm, and the difference between the distance rb and the distance ra of the cam surface 3b is 0.2 mm, 150 N More fixing force can be obtained.

Further, according to the present embodiment, a lower plate 7 displaceable like the upper plate 6 is provided below the drill shaft 10 in the through hole 2a. As a result, the drill stopper 1 can be reliably fixed to the drill shaft 10 by easily rotating the lever 3 to the closed position regardless of variations in the diameter of the drill shaft 10 due to dimensional tolerances.

Further, according to this embodiment, by using the abutting portion 3c provided on the lever 3, the gap between the C-ring 12 and the body 2 can be accurately and easily adjusted to a predetermined gap. can. Further, the rotating operation of the lever 3 and the movement of the body 2 with respect to the drill shaft 10 can be performed using only one hand. Therefore, while holding the electric drill 13 with one hand, the position of the drill stopper 1 with respect to the C ring 12 can be adjusted using only the other hand.
If the abutting portion 3c is not provided, it is necessary to measure the distance between the distal end surface of the body 2 and the proximal end surface of the C ring 12 visually or using another device, and adjust the position of the drill stopper 1. . Therefore, the operation is complicated and it is difficult to adjust the position of the drill stopper 1 using only the other hand.

Further, according to this embodiment, the main portion 5 and the plates 6 and 7 of the body 2 are arranged coaxially with the drill shaft 10, and the lever 3 rotates in the front-rear direction. can be planned. For example, the maximum outer diameter of the drill stopper 1 can be reduced to 15 mm. As a result, the drill stopper 1 can be prevented from interfering with other surrounding instruments during surgery. For example, in OWHTO, instruments may be inserted into two adjacent holes in bone plate 21 simultaneously. In such a case, the drill stopper 1 can be prevented from interfering with other adjacent instruments.

In the above embodiment, as shown in FIG. 7, the center of gravity G of the entire drill stopper 1 with the lever 3 arranged in the closed position is arranged inside the drill shaft 10 in the through hole 2a. is preferred, and it is more preferred to be arranged on or near the longitudinal axis of the drill shaft 10 (that is, the central axis O) in the through hole 2a.
According to this configuration, by bringing the center of gravity G of the drill stopper 1 closer to the central axis of the drill shaft 10, the vibration of the drill shaft 10 during rotation of the drill shaft 10 can be reduced.

In the drill stopper 1 of FIGS. 1 to 3C, a recess 5b recessed toward the central axis O is provided in the lower portion of the main portion 5 in order to adjust the position of the center of gravity G. As shown in FIG. In the absence of the recess 5b, the center of gravity G is biased below the central axis O due to the cutout of the upper portion of the main portion 5. As shown in FIG. By providing the concave portion 5b, the center of gravity G is shifted upward and arranged in the vicinity of the central axis O. As shown in FIG.

The concave portion 5b preferably has a shape that fits the operator's finger. In one example, when operating the drill stopper 1 , the operator places the pad of the index finger extended in the horizontal direction on the lower surface of the main portion 5 . Therefore, it is preferable that the concave portion 5b is formed of a concave curved surface extending in the left-right direction. According to this configuration, the operator can grip the drill stopper 1 more firmly with his/her fingers, and the operability can be improved.

In the above embodiment, the lever 3 opens and closes in the front-rear direction by rotating around the rotation axis P in the left-right direction. Alternatively, as shown in FIGS. It may be configured to open and close in the left-right direction by rotating around a rotation axis P parallel to the axis O. FIGS. 9A and 9B are front views of the drill stopper 1 viewed from the tip side in the direction along the axes O and P. FIG.

In another embodiment of FIGS. 8 to 9B, the body 2 includes a substantially semicircular plate-like main portion 5 and an upper plate 6 extending in the left-right direction. A right end portion of the upper plate 6 is fixed to the main portion 5, and the upper plate 6 is supported by the main portion 5 in a cantilever manner. The left end of the upper plate 6 is vertically displaceable. By pressing the left end of the upper plate 6 by the cam lever 3, the upper plate 6 is pressed against the side surface of the drill shaft 10 and the body 2 is fixed to the drill shaft 10 in the through hole 2a. A recess 5b is provided in the lower part of the main part 5 so that the center of gravity G of the entire drill stopper 1 with the lever 3 arranged in the closed position is positioned inside the drill shaft 10 in the through hole 2a. placed in Also in this embodiment, a lower plate 7 (not shown) may be provided.

In the above-described embodiment, the lever 3 is a cam lever, but the lever 3 may have other structure as long as it can press the upper plate 6 by rotating to the closed position. A locking mechanism may be provided to temporarily lock the lever 3 in the closed position, if desired.
In the above embodiment, the pressing member 6 and the adjusting member 7 are plate-like members supported in a cantilever manner. Other forms may be used as long as they can be displaced at least downward. For example, the pressing member and the adjusting member may be members of any shape supported by the main portion 5 via an elastic member such as a spring, and may be displaceable by deformation of the elastic member.

In the above embodiment, the abutting portion 3c is provided on the upper surface 3d at a position between the tip end and the base end of the lever 3, but the configuration of the abutting portion is not limited to this. It can be changed as appropriate. FIGS. 10A to 11C show other configuration examples of the abutting portion. FIGS. 10C to 11C show a usage example in which the abutting portion 3c abuts against the base end surface of the drill guide 11, which is another member 12. FIG.

10A to 10C, a convex portion 3f protruding from the upper surface 3d is provided at the proximal end of the lever 3, and the abutting portion 3c is configured from the proximal end surface of the lever 3 (the proximal end surface of the convex portion 3f). The convex portion 3f is provided with a concave portion 3g for receiving the drill shaft 10 in the radial direction. As shown in FIG. 10C, by fitting the drill shaft 10 in the concave portion 3g, the lever 3 is arranged at the open position without interfering with the drill shaft 10, and the abutment is arranged on the most distal side of the drill stopper 1. The portion 3c can be abutted against the member 12. As shown in FIG.

11A to 11C, the abutting portion 8a is provided on the body 2 and can be displaced in the front-rear direction with respect to the body 2 by elastic deformation of the elastic member 8. As shown in FIG.
The elastic member 8 is a tubular member such as a coil spring. As shown in FIG. 11C, at the tip of the body 2, a substantially cylindrical slit 2b is formed radially outwardly of the through hole 2a and coaxial with the central axis O to accommodate the elastic member. The elastic member 8 protrudes from the front end surface of the body 2 in a natural state, and is compressed in the front-rear direction so that the entire elastic member 8 can be accommodated in the slit 2b. The abutting portion 8a is formed from the tip surface of the elastic member 8. As shown in FIG. The abutting portion 8a may be composed of a separate member fixed to the tip of the elastic member 8. As shown in FIG.

As shown in FIG. 11A, the abutting portion 8a at the tip of the elastic member 8 in the natural state is abutted against the base end surface of the other member 12, thereby reducing the gap between the member 12 and the body 2 to the elastic member 8. can be adjusted to a predetermined spacing L determined by the natural length of the . After that, the drill shaft 10 can be advanced while compressing the elastic member 8 until the tip surface of the body 2 contacts the member 12 .

Reference Signs List 1 drill stopper 2 body 2a through hole 3 lever, cam lever 3b cam surfaces 3c, 8a butting portion 6 upper plate (holding member)
7 lower plate (adjustment member)
10 drill axis O central axis line P rotation axis line

Claims (4)

A drill stopper attached to a drill shaft of a bone drilling surgical drill, comprising:
a body having a through hole through which the drill shaft passes;
a pressing member provided in the body and forming a part of the inner surface of the through hole;
a lever for locking and unlocking the body to the drill shaft in the through hole;
the pressing member is displaceable in a direction toward the central axis of the through hole, and presses the drill shaft by displacement in the direction toward the central axis;
The lever is
arranged on the side opposite to the central axis with respect to the pressing member,
The body is rotatable about a predetermined rotation axis between a fixed position in which the pressing member is pressed in a direction toward the central axis to displace the pressing member and a release position in which the pressing member is released. A drill stopper supported by an adjusting member provided in the body and forming another part of the inner surface of the through hole;
the pressing member and the adjusting member are opposed to each other across the central axis,
The adjusting member is displaceable in a direction away from the central axis, depending on the pressing force applied to the adjusting member via the drill shaft from the pressing member pressed by the lever in the fixed position. A drill stop according to claim 1, which is displaceable . The lever is a cam lever having a cam surface curved around the predetermined rotation axis at one end of the lever connected to the body. rotate and
3. A drill according to claim 1 or 2, wherein the distance from said axis of rotation to the point of contact of said cam surface with said pressing member gradually increases as said lever rotates from said unlocked position to said locked position. stopper. 4. The method according to any one of claims 1 to 3, wherein the center of gravity of the drill stopper in the direction orthogonal to the central axis is arranged inside the drill shaft in the through hole when the lever is arranged at the fixed position. A drill stopper according to any one of the preceding claims.

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