TWI833483B - Drill bit stop - Google Patents

Abstract

The drill bit stopper 1 is provided with: a body 2 having a through hole 2a for the drill shaft to penetrate; and a control lever 3 for fixing the body 2 in a fixed position of the drill shaft in the through hole 2a and for removing the body 2 from the drill bit. Between the released and unfixed positions of the shaft, it is supported by the body 2 in a manner that it can rotate around a specific rotation axis. The joystick 3 has a contact portion 3c that is in contact with other members mounted on the drill shaft in the direction along the central axis O of the through hole 2a. The contact portion 3c is in a position where the joystick 3 is unfixed. position, it is arranged at a position spaced apart from the body 2 in the direction of the central axis O.

Description

Drill bit stop

The present invention relates to a drill bit stopper.

Conventionally, a drill stopper attached to a surgical drill used to make a hole in a bone has been known (see, for example, Patent Documents 1 and 2).

As shown in Figure 12, when the screw 20 is fixed on the tubular bone A such as the tibia in a bicortical fixation manner, through holes will be drilled on the proximal and contralateral cortical bones D1 and D2. Figure 12 shows a medial open Wedge High Tibial Osteotomy (OWHTO: Open Wedge High Tibial Osteotomy), in which the bone plate 21 is fixed to the medial surface of the tibia A with screws 20. Bicortical fixation is a fixation method in which the screws 20 penetrate the proximal and contralateral cortical bones D1 and D2. In this method, the screw 20 is fixed on the hard cortical bone at two places, so the screw 20 can achieve high fixation strength to the bone A.

[Prior technical literature] [Patent Document]

[Patent Document 1] Japanese Patent Application Publication No. 2014-128313

[Patent Document 2] Japanese Patent Application Publication No. 2013-154138

On the opposite side of bone A, there are nerves B and blood vessels C and other tissues. In Patent Documents 1 and 2, when drilling a hole in the contralateral cortical bone D2, the position of the drill stopper can be roughly adjusted so that the distance from the surface of the proximal cortical bone D1 to the front end of the stopper is approximately equal to that of the opposite cortical bone D2. The thickness of the cortical bone D2 on the opposite side is the same. Therefore, the advancement of the drill bit will stop after the front end of the drill bit penetrates the cortical bone D2 on the opposite side.

However, in order to correctly control the protrusion amount of the drill bit from the contralateral cortical bone D2 with the drill bit stopper, the position of the drill bit stopper relative to the drill bit must be correctly adjusted.

The present invention was made in view of the above-mentioned circumstances, and an object thereof is to provide a drill bit stopper that can accurately and simply adjust the position relative to the drill bit.

One aspect of the present invention is a drill bit stopper installed on a drill shaft of a surgical drill bit used to drill holes in bones, and is provided with: a main body having a through hole for the drill shaft to penetrate; and a control lever. The body is supported in such a manner that it can rotate about a specific rotation axis between a fixed position of the drill shaft that fixes the body in the through hole and an unfixed position in which the body is released from the drill shaft. The operating lever has a contact portion that contacts another member mounted on the drill shaft in a direction along the central axis of the through hole, and the contact portion is when the operating lever is in the unlocking position. In this state, it is arranged at a position spaced apart from the main body in the direction of the central axis of the through hole.

1: Drill bit stopper

2: Ontology

2a:Through hole

3: Joystick, cam lever

3b: Cam surface

3c,8a: Contact part

3f:convex part

3g: concave part

6: Upper plate (pressing member)

7: Lower plate (adjustment component)

10:Drill shaft

12: Component (C-ring)

O: central axis

P: axis of rotation

Q:Central axis

FIG. 1 is a side view showing the use state of the drill stopper according to the embodiment.

FIG. 2 is an exploded perspective view of the drill bit stopper of FIG. 1 .

FIG. 3A is a longitudinal sectional view for explaining the function of the drill bit stopper in FIG. 1 , showing the operating lever in the open position.

FIG. 3B is a longitudinal sectional view for explaining the function of the drill bit stopper in FIG. 1 , showing the operating lever in the closed position.

FIG. 3C is a longitudinal sectional view for explaining the function of the drill bit stopper in FIG. 1 , showing a state in which the drill shaft is arranged in the through hole and the operating lever is in the closed position.

Figure 4 is a side view of the front end of the cam lever provided with a cam surface.

FIG. 5 is an explanatory diagram of how to use the contact portion of the joystick.

FIG. 6 is an explanatory diagram of a step of drilling a hole in a bone using a drill bit equipped with the drill bit stopper of FIG. 1 .

FIG. 7 is a front view illustrating the position of the center of gravity of the drill bit stopper of FIG. 1 .

Fig. 8 is a side view showing the use state of the drill stopper according to another embodiment.

Figure 9A is a front view of the drill bit stopper of Figure 8, showing the operating lever in the open position.

Figure 9B is a front view of the drill bit stopper of Figure 8, showing the operating lever in the closed position.

FIG. 10A is a perspective view of the drill stopper showing a modified example of the contact portion, showing the state in which the operating lever is in the open position.

FIG. 10B is a perspective view of the drill bit stopper of FIG. 10A with the joystick in the closed position.

FIG. 10C is a side view illustrating how to use the contact portions of 10A and 10B.

11A is a side view of a drill stopper showing another modified example of the contact portion, and is an explanatory diagram of how to use the contact portion.

FIG. 11B is a diagram showing a state in which the main body is in contact with other members due to compression of the elastic member.

Figure 11C is an exploded perspective view of the drill bit stopper of Figures 11A and 11B.

Figure 12 is a diagram explaining OWHTO.

Hereinafter, a drill stopper according to an embodiment of the present invention will be described with reference to the drawings.

As shown in FIG. 1 , the drill stopper 1 of this embodiment is installed on the side surface of the drill shaft 10 of a surgical drill used to drill holes in bones, and is used to limit the insertion amount of the drill shaft 10 into the bone. Drill stops 1 are used especially when making inferior holes in the bone for fixation of bicortical screws.

For example, in the medial open high tibial osteotomy (OWHTO) shown in Figure 12, in order to fix the bone plate 21 to the tibia A more strongly, the screws 20 disposed on the distal side of the osteotomy part need to be double-sided. Cortical fixation is used to fix the tibia A. Nerve B and artery C exist on the extension line of screw 20, and the distance from the outer surface of the contralateral cortical bone D2 to nerve B and artery C is about 10 mm to 20 mm. Therefore, it is better to control the protrusion amount of the front end of the drill shaft 10 protruding from the outer surface of the contralateral cortical bone D2 to 2 mm to 3 mm.

As shown in FIGS. 1 and 2 , the drill bit stopper 1 is provided with: a body 2 having a through hole 2 a for the drill shaft 10 to penetrate; and a lever 3 for fixing the body 2 to the drill shaft in the through hole 2 a. 10 and release its fixation from the drill shaft 10; and pin 4, which is used to connect the joystick 3 to the main body 2.

The main body 2, the joystick 3 and the pin 4 are made of metal materials with biocompatibility and strength such as stainless steel.

As shown in FIGS. 2 to 3C , the main body 2 includes a main part 5 constituting the main part of the main body 2 , an upper plate (pressing member) 6 and a lower plate (adjusting member) 7 supported by the main part 5 . In one example, the main portion 5 and the panels 6, 7 are formed as a single seamless component. 3A to 3C are longitudinal sectional views of the drill stopper 1 taken along a plane including the central axis O of the through hole 2 a and perpendicular to the rotation axis P of the joystick 3 .

The main part 5 is a substantially partially cylindrical member having a part in the circumferential direction cut out in the longitudinal direction, and the joystick 3 is a plate-shaped member arranged in the cutout part of the main part 5 . The front end portion of the main portion 5 and the front end portion of the joystick 3 are formed with pin holes 5a, 3a that communicate with each other in a direction perpendicular to the central axis O. By the pin 4 inserted into the pin holes 5a, 3a, the front end of the joystick 3 is connected to the front end of the body 2 in a manner capable of rotating around the predetermined rotation axis P. The axis of rotation P is the central axis of the pin 4 . Both ends of the pin 4 are fixed to the main part 5 through welding or other methods.

Hereinafter, the direction parallel to the central axis O is defined as the front-rear direction of the drill stopper 1, the direction parallel to the rotation axis P is defined as the left-right direction of the drill stop 1, and the direction perpendicular to both the central axis O and the rotation axis P is defined as The direction is defined as the up and down direction of drill stop 1. The control lever 3 is arranged above the through hole 2a.

The upper plate 6 and the lower plate 7 are thin plate-shaped members extending parallel to the central axis O, and face each other in the up-down direction across the central axis O. The upper plate 6 is arranged on the upper side with respect to the through hole 2a, and the lower plate 7 is arranged on the lower side with respect to the through hole 2a. The plates 6 and 7 are arranged inside the main part 5, and the inner surfaces 6a and 7a of the plates 6 and 7 on the central axis O side 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 the other part of the cylindrical inner surface of the through-hole 2a.

The upper plate 6 is supported by the main part 5 in a manner that is elastically displaceable at least in the downward direction, that is, toward the central axis O. The upper plate 7 is supported by the main part 5 in a manner capable of elastic displacement at least in the downward direction, that is, in the direction away from the central axis O.

Specifically, the base ends of each plate 6 and 7 are fixed to the main part 5, and each plate 6 and 7 is supported by the main part 5 in a cantilever manner. The front end of each plate 6, 7 is a free end displaceable in the up and down direction. By the deflection of the plates 6 and 7 formed of thin plates, the front ends of the plates 6 and 7 are elastically displaced in the up and down directions.

The joystick 3 is arranged on the opposite side of 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 relative to the body 2 by rotating around the rotation axis P. Specifically, the joystick 3 can rotate around the rotation axis P between the open position (unfixed position) shown in FIG. 3A and the closed position (fixed position) shown in FIGS. 3B and 3C .

In the closed position, the operating lever 3 will press the upper plate 6 downward, thereby fixing the body 2 to the position of the drill shaft 10 in the through hole 2a. Specifically, the upper plate 6 pressed by the operating rod 3 will be displaced downward due to deflection, as shown in FIG. 3C , so that the inner surface 6 a is pressed against the side surface of the drill shaft 10 in the through hole 2 a. Thereby, the drill bit stopper 1 can be fixed to the drill shaft 10 through friction between the inner surface 6a and the side surface of the drill shaft 10.

In the open position, the joystick 3 will release the upper plate 6, thereby releasing the fixed position of the drill shaft 10 by the body 2. Specifically, the upper plate 6 released from the pressing will be displaced upward by the elastic restoring force, thereby releasing the fixation of the drill spindle 10 by the drill bit stopper 1 .

Here, as shown in FIG. 3C , the pressing force applied from the joystick 3 to the upper plate 6 is also applied to the lower plate 7 through the drill spindle 10 . Therefore, like the upper plate 6, the lower plate 7 is also displaced downward due to deflection. Through the displacement of the lower plate 7, as described later, the force required to rotate the joystick 3 to the closed position is not affected by the deviation of the diameter of the drill shaft 10, and can be adjusted within a certain range.

In this embodiment, the operating lever 3 is a cam lever having a cam surface 3b at the front end connected to the main body 2 . The cam surface 3b is a convex curved surface that is composed of the front end surface, the lower surface, and the upper surface of the front end portion of the joystick 3 and is curved around the rotation axis P. The cam surface 3b will be in slight contact with the upper plate 6 when the lever 3 is in the open position, or will be slightly separated from the upper plate 6, and rotate around the axis of rotation while contacting the upper plate 6 by the rotation of the lever 3 to the closed position. P rotation. The distance from the rotation axis P to the contact point of the cam surface 3b and the upper plate 6 gradually increases as the joystick 3 rotates from the open position to the closed position. Therefore, as the lever 3 approaches the closed position, the pressing force exerted by the cam surface 3b on the upper plate 6 will gradually increase. add. When the joystick 3 is in the closed position, the friction between the cam surface 3b and the upper plate 6 will prevent the joystick 3 from rotating in the opening direction, thereby stably fixing the joystick 3 in the closed position.

Figure 4 shows an example of a preferred design of the cam surface 3b. The cam surface 3b is curved in an arc shape or substantially an arc shape around a central axis Q parallel to the rotation axis P. In the closed position, the center axis Q of the cam surface 3b is eccentric to the lower side relative to the rotation axis P. Therefore, the distance rb in FIG. 4 is greater than the distance ra, and the distance from the rotation axis P to the cam surface 3b gradually increases from point α to point β. Point α is the lowermost end of the cam surface 3b in the open position, and point β is the lowermost end of the cam surface 3b in the closed position.

When the plates 6 and 7 are not pressed by the operating rod 3, the diameter of the through hole 2a is slightly larger than the diameter of the drill shaft 10. 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 spindle 10 may vary due to dimensional tolerances. The drill bit stopper 1 can cope with the diameter deviation of the drill shaft 10 by providing the lower plate 7 .

That is, in the case where the lower plate 7 is not provided, when the diameter of the drill shaft 10 is larger than the standard value, the resistance of the cam rod 3 to rotate to the closed position increases, which may make it difficult for the cam rod 3 to rotate to the closed position, or cause the drill shaft to rotate to the closed position. 10 side surface deformation. In the case where the lower plate 7 is provided, with the displacement of the lower plate 7 in response to the magnitude of the pressing force exerted by the cam rod 3 on the upper plate 6, even if the diameter of the drill shaft 10 is larger than the standard value, the drill shaft 10 can be drilled with the same diameter as the drill shaft 10. Less than the standard value, approximately the same force rotates cam lever 3 to the closed position.

The design of the cam surface 3b is preferably such that when the diameter of the drill shaft 10 is within the dimensional tolerance, the lower plate 7 will inevitably deflect and displace.

The operating lever 3 further has a contact portion 3c that contacts other components mounted on the drill shaft 10 in the direction along the central axis O. As shown in FIG. 5 , when the joystick 3 is in the open position, the contact portion 3 c is disposed at a position facing the front end surface of the body 2 in the front-rear direction and spaced a specific distance L from the body 2 in the front-rear direction, and Toward the side opposite to body 2. therefore, By causing the contact portion 3c to contact the base end surface of the other member 12 when the joystick 3 is in the open position, the distance between the member 12 and the body 2 can be adjusted to a specific distance L.

In one example, the upper surface 3d of the joystick 3 is provided with a convex portion 3e protruding from the upper surface 3d. The contact portion 3c is formed by the side surface of the convex portion 3e on the base end side of the joystick 3. The upper surface 3d of the joystick 3 is a surface disposed on the upper side when the joystick 3 is in the closed position. The angle formed by the upper surface 3d and the contact portion 3c is preferably 90° or an angle close to 90°. In this case, the distance between the member 12 and the body 2 can be adjusted by bringing the angle between the upper surface 3d and the contact portion 3c into contact with the angle between the side surface and the base end surface of the member 12.

The distance L is designed based on the thickness of the cortical bone D2 on the opposite side and the specific protrusion amount when the front end of the drill shaft 10 protrudes from the outer surface of the cortical bone D2 on the opposite side. In an example, assuming that the standard thickness of the cortical bone D2 is about 5mm and the specific protrusion amount is about 2mm~3mm, the interval L is designed to be 8mm.

Next, a method of drilling holes in a bone using a drill bit equipped with the drill bit stopper 1 will be described with reference to FIG. 6 .

Figure 6 shows the steps of drilling holes on bone A for fixing the screws 20 under the bone A using bicortical fixation during the operation of 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 the tibia or thigh bone. The soft spongy bone E on the inside is covered by the hard cortical bone D on the outside. A cylindrical drill guide 11 for guiding the drill shaft 10 is installed on the bone plate 21 .

First, in step S1 , the operator fixes the drill bit stopper 1 to the base end of the drill shaft 10 and installs the C-ring 12 at a desired position between the front end of the drill shaft 10 and the drill bit stopper 1 . The C-shaped ring 12 is fixed to the drill shaft 10 by friction between the inner surface of the C-shaped ring 12 and the side surface of the drill shaft 10 , and can move in the longitudinal direction of the drill shaft 10 against friction. The use of the C-shaped ring 12 is based on the following purposes: to grasp the insertion amount of the drill shaft 10 into the bone A according to the distance between the base end of the drill guide 11 and the C-shaped ring 12, and to ensure that the drill bit guides The distance between the base end surface of the lead 11 and the drill bit stopper 1.

Next, in step S2, the operator will operate the electric drill 13 to rotate the drill shaft 10, and use the rotating drill shaft 10 to drill a hole on the bone A from the outer surface of the proximal cortical bone D1 to the inner surface of the contralateral cortical bone D2. . During the drilling process on bone A, after the C-shaped ring 12 contacts the base end surface of the drill bit guide 11 , the drill shaft 10 will move relative to the C-shaped ring 12 . When the front end of the drill shaft 10 contacts the inner surface of the contralateral cortical bone D2, the operator will temporarily stop the rotation and advancement of the drill shaft 10. Because when the front end of the drill shaft 10 contacts the inner surface of the contralateral cortical bone D2, the resistance against the advancement of the drill shaft 10 will increase sharply. The operator can recognize the increase in resistance transmitted to the hand holding the electric drill 13. The front end of the drill shaft 10 has contacted the inner surface of the contralateral cortical bone D2.

Next, in step S3, the operator releases the fixation of the drill shaft 10 by the drill bit stopper 1 by rotating the joystick 3 to the open position. Next, after confirming that the C-ring 12 is in contact with the base end surface of the drill bit guide 11 , the operator moves the drill bit stopper 1 to the C-ring 12 side relative to the drill shaft 10 to position the drill bit stopper 1 When the contact portion 3c is in contact with the base end surface of the C-ring 12, the drill bit stopper 1 is fixed to the drill shaft 10 again by rotating the operating lever 3 to the closed position.

Next, in step S4 , the operator will start to rotate and advance the drill shaft 10 again, and advance the drill shaft 10 until the front end surface of the body 2 contacts the base end surface of the C-shaped ring 12 . When the front end surface of the main body 2 contacts the base end surface of the C-shaped ring 12, the operator stops the rotation and advancement of the drill shaft 10 and terminates drilling.

In addition, the C-shaped ring 12 is installed on the drill shaft 10 according to the needs, but is not necessarily used. When the C-ring 12 is not used, in step S3, the drill bit stopper 1 is positioned at a position where the contact portion 3c is in contact with the base end surface of the drill bit guide 11, and in step S4, the drill spindle is 10 advances until the front end surface of the body 2 contacts the base end surface of the drill bit guide 11.

In this way, according to this embodiment, when the protrusion amount of the front end of the drill shaft 10 from the outer surface of the contralateral cortical bone D2 reaches a specific protrusion amount, the front end surface of the body 2 will abut against the base of the C-shaped ring 12 end surface. Thereby, when the advancement of drill shaft 10 will be mechanically blocked, the operator can also recognize It is recognized that the front end of the drill shaft 10 has protruded only a certain protrusion amount from the outer surface of the contralateral cortical bone D2. Therefore, excessive perforation of the bone A can be prevented.

Furthermore, according to this embodiment, the drill stopper 1 is directly fixed to the side surface of the drill shaft 10 by friction between the plates 6 and 7 and the drill shaft 10 . Therefore, regardless of the type of chuck of the electric drill 13 , whether it is an electric type or a manual type, the drill bit stopper 1 can be used on various types of drills, and a highly versatile drill bit stopper 1 can be provided. In addition, since there is no restriction on the position where the drill bit stopper 1 is installed on the drill shaft 10, the installation position can be continuously displaced in the longitudinal direction of the drill shaft 10, so that the drill bit stopper 1 can be installed at any position on the drill shaft 10. .

Furthermore, according to this embodiment, fixing and unfixing of the drill shaft 10 by the drill stopper 1 is performed only by the rotation of the cam rod 3 . In addition, while the cam rod 3 can be rotated with a smaller force, it can also obtain a larger fixing force exerted by the body 2 on the drill shaft 10 . Therefore, the operator can rotate the cam lever 3 using only the thumb of one hand, for example, and can easily perform the operations of fixing and releasing the drill stopper 1 .

In one design example, when the diameter of the drill shaft 10 is 4.85mm~4.90mm, the diameter of the through hole 2a is 5.0mm, and the difference between the distance rb and the distance ra of the cam surface 3b is 0.2mm, a fixation force of more than 150N can be obtained force.

Furthermore, according to this embodiment, the lower plate 7 displaceable like the upper plate 6 is provided on the lower side of the drill shaft 10 in the through hole 2 a. Thereby, the drill bit stopper 1 can be reliably fixed to the drill shaft 10 by easily rotating the operating lever 3 to the closed position without being affected by the diameter deviation of the drill shaft 10 due to dimensional tolerances.

Furthermore, according to this embodiment, by using the contact portion 3c provided on the joystick 3, the distance between the C-ring 12 and the main body 2 can be accurately and easily adjusted to a specific distance. In addition, the rotation operation of the joystick 3 and the movement of the body 2 relative to the drill shaft 10 can be performed with only one hand. therefore, It is possible to adjust the position of the drill stop 1 relative to the C-ring 12 using only the other hand while holding the drill 13 with one hand.

If the contact portion 3c is not provided, it is necessary to visually or use other devices to measure the distance between the front end surface of the body 2 and the base end surface of the C-ring 12, and then adjust the position of the drill stop 1. Therefore, not only is the operation complicated, but it is also difficult to adjust the position of the drill stopper 1 using only the other hand.

Furthermore, according to this embodiment, since the main part 5 and the plates 6 and 7 of the body 2 are arranged coaxially with the drill shaft 10 and the operating rod 3 can rotate in the front-rear direction, the shaft diameter of the drill stopper 1 can be reduced. For example, the maximum outer diameter of the drill stop 1 can be reduced to 15 mm. This can prevent the drill stopper 1 from interfering with other surrounding instruments during surgery. For example, in OWHTO, instruments are sometimes inserted into two adjacent holes on the bone plate 21 at the same time. In this case, it is possible to prevent the drill stopper 1 from interfering with other adjacent instruments.

In the above embodiment, as shown in FIG. 7 , when the operating lever 3 is in the closed position, the overall center of gravity G of the drill bit stopper 1 is preferably disposed inside the drill shaft 10 in the through hole 2 a, and more preferably is disposed in the through hole 2 a. On the long axis of the drill shaft 10 (ie, the central axis O) in the hole 2a, or near the long axis.

According to this structure, by bringing the center of gravity G of the drill stopper 1 close to the central axis of the drill shaft 10, it is possible to reduce the vibration of the drill shaft 10 when the drill shaft 10 rotates.

In the drill stopper 1 shown in FIGS. 1 to 3C , in order to adjust the position of the center of gravity G, a recess 5 b that is depressed toward the central axis O is provided in the lower part of the main part 5 . In the absence of the recessed portion 5b, the upper portion of the main portion 5 is cut off, causing the center of gravity G to be biased toward the lower side of the central axis O. By providing the recess 5b, the center of gravity G can be moved upward and placed near the central axis O.

The recessed portion 5b preferably has a shape suitable for the operator's fingers. For example, when operating the drill bit stopper 1 , the operator will place the pad of his index finger extending in the left-right direction on the lower surface of the main body portion 5 . Therefore, the recessed portion 5b is preferably formed by a concave curved surface extending in the left-right direction. by this structure, the operator can hold the drill bit stopper 1 more firmly with his fingers, thereby improving operability.

In the above embodiment, the joystick 3 is opened and closed in the front-rear direction by rotating around the rotation axis P in the left-right direction. However, the joystick 3 may also be opened and closed in the parallel direction as shown in FIGS. 8 to 9B. It is configured to rotate about the rotation axis P of the central axis O and open and close in the left and right directions. 9A to 9B are front views of the drill stopper 1 viewed from the front end side along the directions of the axes O and P.

In another embodiment of FIGS. 8 to 9B , the main body 2 is provided with a substantially semicircular plate-shaped main part 5 and an upper plate 6 extending in the left-right direction. The right end of the upper plate 6 is fixed on the main part 5, and the upper plate 6 is supported by the main part 5 in a cantilever manner. The left end of the upper plate 6 is displaceable in the up and down direction. When the cam rod 3 presses the left end of the upper plate 6, the upper plate 6 will be pressed against the side surface of the drill shaft 10, thereby fixing the body 2 to the drill shaft 10 in the through hole 2a. The lower part of the main part 5 is provided with a recessed part 5b, whereby the center of gravity G of the entire drill stopper 1 is located inside the drill shaft 10 in the through hole 2a when the operating lever 3 is in the closed position. In this embodiment, a lower plate 7 (not shown in the figure) may be provided.

In the above embodiment, although the joystick 3 is a cam lever, as long as the joystick 3 can press the upper plate 6 by rotating to the closed position, the joystick 3 can also be a joystick with other structures. If necessary, a fixing mechanism for temporarily fixing the joystick 3 in the closed position can also be provided.

In the above embodiment, although the pressing member 6 and the adjusting member 7 are plate-shaped members supported in a cantilever manner, as long as the pressing member and the adjusting member can be elastically displaced at least downward by the pressing force exerted on them by the joystick 3 , other forms can also be adopted. For example, the pressing member and the adjusting member may be members of any shape supported by the main part 5 via an elastic member such as a spring, or may be displaceable by deformation of the elastic member.

In the above-described embodiment, the contact portion 3c is provided on the upper surface 3d between the front end and the base end of the joystick 3, but the structure of the contact portion is not limited to this and may be appropriately modified. 10A to 11C show other structural examples of the contact portion. 10C to 11C show an example of use in which the contact portion 3 c is brought into contact with the base end surface of the drill guide 11 which is another member 12 .

In FIGS. 10A to 10C , the base end of the joystick 3 is provided with a convex portion 3f protruding from the upper surface 3d, and the contact portion 3c is formed by the base end surface of the joystick 3 (the base end surface of the convex portion 3f). The convex portion 3f is provided with a recessed portion 3g for receiving the drill shaft 10 in the radial direction. As shown in FIG. 10C , by inserting the drill shaft 10 into the recessed portion 3 g, the operating lever 3 can be placed in the open position without interfering with the drill shaft 10 , and the resistor disposed on the frontmost end side of the drill bit stopper 1 can be moved. The contact portion 3c is in contact with the member 12 .

As shown in FIGS. 11A to 11C , the contact portion 8 a is provided on the body 2 and can be displaced in the front-rear direction relative to the body 2 by elastic deformation of the elastic member 8 .

The elastic member 8 is a cylindrical member like a coil spring. As shown in FIG. 11C , a substantially cylindrical slit 2 b for accommodating the elastic member is formed at the front end of the body 2 , and is formed coaxially with the central axis O outside the through hole 2 a in the radial direction. The elastic member 8 protrudes from the front end surface of the body 2 in a natural state, and after being compressed in the front-rear direction, the entire elastic member 8 can be accommodated in the slit 2b. The contact portion 8 a is formed by the front end surface of the elastic member 8 . The contact portion 8a may also be composed of other members fixed to the front end of the elastic member 8.

As shown in FIG. 11A , by making the contact portion 8 a at the front end of the elastic member 8 in the natural state contact the base end surface of the other member 12 , the distance between the member 12 and the body 2 can be adjusted to the elastic member. A specific interval L determined by the natural length of 8. Thereafter, the drill shaft 10 can be advanced while compressing the elastic member 8 until the front end surface of the body 2 contacts the member 12 .

1: Drill bit stopper

2: Ontology

2a:Through hole

3: Joystick, cam lever

3a,5a: pin hole

3b: Cam surface

3c: Contact part

3d: upper surface

3e:convex part

4:pin

5b: concave part

6: Upper plate (pressing member)

6a,7a:Inner surface

7: Lower plate (adjustment component)

O: central axis

Claims (6)

A drill bit stopper is installed on the drill shaft of a surgical drill bit used to drill holes in bones, and is provided with: a main body having a through hole for the drill shaft to penetrate; and a control rod for fixing the main body Between the fixed position of the drill shaft in the through hole and the unfixed position of releasing the main body from the drill shaft, the main body is supported by the main body in a manner that can rotate about a specific rotation axis; the joystick has an abutment part, the contact part is in contact with other members installed on the drill shaft in the direction along the central axis of the through hole; the contact part is arranged on the state where the joystick is in the unlocked position. A position spaced apart from the main body in the direction of the central axis of the through hole. The drill bit stopper according to claim 1, further comprising a pressing member provided on the body and forming a part of the inner surface of the through-hole; the pressing member is displaceable in the direction of the central axis of the through-hole; The operating lever is arranged on the opposite side of the central axis with respect to the pressing member, presses the pressing member in the direction of the central axis at the fixed position, and releases the pressing member at the unfixed position. The drill bit stopper according to claim 2, which is provided with an adjustment member provided on the body and forming other parts of the inner surface of the through hole; the pressing member and the adjustment member are opposite to each other across the central axis; The adjustment member is displaceable in a direction away from the central axis. The drill bit stopper according to claim 2 or 3, wherein the aforementioned joystick is a cam rod having a cam surface bent around the aforementioned specific rotation axis at one end of the aforementioned joystick connected to the aforementioned body, and the aforementioned cam surface is Due to the rotation of the aforementioned joystick, it rotates while contacting the aforementioned pressing member; the distance from the aforementioned rotation axis to the contact point of the aforementioned cam surface and the aforementioned pressing member is determined by the rotation of the aforementioned joystick from the aforementioned unlocking position to the aforementioned fixed position and gradually increase. The drill bit stopper according to any one of claims 1 to 3, wherein the center of gravity of the drill bit stopper is disposed inside the drill shaft in the through hole. The drill bit stopper according to claim 4, wherein the center of gravity of the drill bit stopper is disposed inside the drill shaft in the through hole.