TW202416905A - Drill stopper - Google Patents

Abstract

The drill stopper 1 comprises: a main body 2 having a through hole 2a for a drill shaft to pass through; a pressing member 6 provided on the main body 2 and forming a part of the inner surface of the through hole 2a; and an operating rod 3 for fixing the main body 2 to the drill shaft in the through hole 2a and releasing the fixing thereof from the drill shaft. The pressing member 6 can be displaced in the direction of the central axis O of the through hole 2a. The operating rod 3 is arranged on the opposite side of the central axis O with respect to the pressing member 6, and is supported by the main body 2 in such a manner that the pressing member 6 can be rotated around a specific rotation axis between a fixed position where the pressing member 6 is pressed in the direction of the central axis O and a released position where the pressing member 6 is released.

Description

Drill stopper

The present invention relates to a drill stopper.

In the past, drill stoppers mounted on surgical drill bits for drilling holes in bones are known (for example, see patent documents 1 and 2). As shown in FIG12, when a screw 20 is fixed to a tubular bone A such as a tibia in a bicortical fixation manner, through holes are drilled in the proximal and contralateral cortical bones D1 and D2. FIG12 shows an open wedge high tibia osteotomy (OWHTO), which is a method of fixing a bone plate 21 to the medial surface of the tibia A with a screw 20. Bicortical fixation is a fixation method in which a screw 20 is penetrated through the proximal and contralateral cortical bones D1 and D2. This method allows the screw 20 to be fixed on the hard cortical bone at two locations, so that the screw 20 can obtain a high fixing strength on the bone A.

On the opposite side of bone A, there may be tissues such as nerves B and blood vessels C. The drill stoppers of Patent Documents 1 and 2 are used to prevent the front end of the drill shaft from excessively protruding from the opposite cortical bone D2, and are constructed in such a way that the drill stops advancing immediately after the front end of the drill shaft penetrates the opposite cortical bone D2.

[Prior technical literature] [Patent literature] [Patent literature 1] Japanese Patent Publication No. 2014-128313 [Patent literature 2] Japanese Patent Publication No. 2013-154138

[Problem to be solved by the invention] The drill stopper of Patent Document 1 can only be installed on a collet-type electric drill. Therefore, the drill stopper of Patent Document 1 cannot be used for electric drills using other types of chucks such as Hudson Chuck, and lacks versatility and is not very convenient. The drill stopper of Patent Document 2 is a stacked structure having an inner cylinder and an outer cylinder, which can change the position of the front end of the outer cylinder that abuts against the surface of the proximal cortical bone D1 in the long side direction of the drill shaft. By engaging the connecting snap-fitting piece provided on the outer cylinder with any of the multiple connecting grooves provided on the inner cylinder, the outer cylinder can be positioned relative to the inner cylinder. That is, the position of the front end of the outer cylinder is limited by the position of the connecting groove, and the front end of the outer cylinder cannot be fixed in a free position.

The present invention is completed in view of the above situation, and its purpose is to provide a drill stopper with high versatility and capable of being fixed at any position on the drill shaft.

[Technical means for solving the problem] One aspect of the present invention is a drill stopper mounted on a drill shaft of a surgical drill used for drilling a hole in a bone, comprising: a body having a through hole for the drill shaft to pass through; a pressing member provided on the body and forming a part of the inner surface of the through hole; and a lever for fixing the body to the drill shaft in the through hole and releasing the body from the drill shaft in the through hole. The pressing member can be displaced in the direction of the central axis of the through hole, and the operating rod is arranged on the opposite side of the central axis relative to the pressing member, and is supported by the main body in a manner that the pressing member can be rotated around a specific rotation axis between a fixed position where the pressing member is pressed in the direction of the central axis and a released position where the pressing member is released.

Hereinafter, a drill stopper according to one embodiment of the present invention will be described with reference to the drawings. As shown in FIG1 , the drill stopper 1 according to the present embodiment is mounted on the side surface of the drill shaft 10 of a surgical drill used for opening a hole in a bone, and is used to limit the insertion amount of the drill shaft 10 into the bone. In particular, the drill stopper 1 is used when a lower hole for fixing a bicortical screw is opened in a bone.

For example, in the medial open high tibia osteotomy (OWHTO) shown in FIG. 12 , in order to more strongly fix the bone plate 21 to the tibia A, the screw 20 disposed on the distal side of the osteotomy portion needs to be fixed to the tibia A in a bicortical fixation manner. Nerve B and artery C exist on the extension line of the screw 20, and the distance from the outer surface of the contralateral cortical bone D2 to the nerve B and artery C is about 10 mm to 20 mm. Therefore, it is preferred that the protrusion amount of the front end of the drill shaft 10 protruding from the outer surface of the contralateral cortical bone D2 be controlled to 2 mm to 3 mm.

As shown in FIG. 1 and FIG. 2 , the drill stopper 1 comprises: a body 2 having a through hole 2a for the drill shaft 10 to pass through; a lever 3 for fixing the body 2 to the drill shaft 10 in the through hole 2a and releasing the fixing thereof from the drill shaft 10; and a pin 4 for connecting the lever 3 to the body 2. The body 2, the lever 3 and the pin 4 are made of a metal material having 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 part 5 and the plates 6, 7 are formed as a single member without joints. Figs. 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 2a and perpendicular to the rotation axis P of the operating rod 3.

The main part 5 is a component that is roughly partially cylindrical and has a cutout in the longitudinal direction at a portion of the circumference, and the control rod 3 is a plate-shaped component that is arranged at the cutout portion of the main part 5. The front end of the main part 5 and the front end of the control rod 3 are formed with pin holes 5a, 3a that are connected to each other in a direction perpendicular to the center axis O. By inserting the pin 4 in the pin holes 5a, 3a, the front end of the control rod 3 is connected to the front end of the body 2 in a manner that can rotate around a predetermined rotation axis P. The rotation axis P is the center axis of the pin 4. Both ends of the pin 4 are fixed to the main part 5 by means such as welding.

Hereinafter, the direction parallel to the center 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 stopper 1, and the direction perpendicular to both the center axis O and the rotation axis P is defined as the up-down direction of the drill stopper 1. The operating rod 3 is arranged on the upper side relative to 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 are opposed to each other in the vertical direction across the central axis O. The upper plate 6 is arranged on the upper side relative to the through hole 2a, and the lower plate 7 is arranged on the lower side relative to the through hole 2a. The plates 6 and 7 are arranged on the inner side of the main part 5, and the inner surfaces 6a and 7a of the plates 6 and 7 on the central axis O side respectively demarcate a part of the through hole 2a. That is, the inner surface 6a forms a 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 allows elastic displacement at least in the downward direction, that is, in the direction toward the center axis O. The upper plate 7 is supported by the main part 5 in a manner that allows elastic displacement at least in the downward direction, that is, in the direction away from the center axis O. Specifically, the base end of each plate 6, 7 is fixed to the main part 5, and each plate 6, 7 is supported by the main part 5 in a cantilever manner. The front end of each plate 6, 7 is a free end that can be displaced in the vertical direction. The front end of each plate 6, 7 can be elastically displaced in the vertical direction by bending the plates 6, 7 formed by the thin plate.

The operating lever 3 is disposed on the opposite side of the center axis O relative 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 main body 2 by rotating around the rotation axis P. Specifically, the operating lever 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 FIG. 3B and FIG. 3C.

The closed position is when the lever 3 presses the upper plate 6 downward, thereby fixing the body 2 at the position of the drill shaft 10 in the through hole 2a. Specifically, the upper plate 6 pressed by the lever 3 will be displaced downward due to bending, as shown in FIG. 3C, so that the inner surface 6a is pressed against the side surface of the drill shaft 10 in the through hole 2a. Thus, the drill stopper 1 can be fixed to the drill shaft 10 through the friction between the inner surface 6a and the side surface of the drill shaft 10. The open position is when the lever 3 releases the upper plate 6, thereby releasing the fixing of the body 2 to the drill shaft 10. Specifically, the upper plate 6 released from the pressing will move upward due to the 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 operating rod 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 due to bending. Through the displacement of the lower plate 7, as described later, the force required for rotating the operating rod 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 the present embodiment, the operating lever 3 is a cam lever having a cam surface 3b at the front end portion connected to the main body 2. The cam surface 3b is a convex curved surface that is formed by the front end surface, the lower surface, and the upper surface of the front end portion of the operating lever 3 and is bent around the rotation axis P. The cam surface 3b slightly contacts the upper plate 6 when the operating lever 3 is in the open position, or slightly separates from the upper plate 6, and rotates around the rotation axis P while contacting the upper plate 6 as the operating lever 3 rotates toward the closed position. The distance from the rotation axis P to the contact point between the cam surface 3b and the upper plate 6 gradually increases as the operating lever 3 rotates from the open position to the closed position. Therefore, as the operating lever 3 approaches the closed position, the pressing force applied by the cam surface 3b to the upper plate 6 will gradually increase. When the operating lever 3 is in the closed position, the friction between the cam surface 3b and the upper plate 6 will prevent the operating lever 3 from rotating in the opening direction, thereby stably fixing the operating lever 3 in the closed position.

FIG. 4 shows an example of a preferred design of the cam surface 3b. The cam surface 3b is bent into an arc shape or a substantially arc shape around a center 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 lowest end of the cam surface 3b in the open position, and point β is the lowest 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 shaft 10 may vary due to dimensional tolerance. The drill 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 the closed position increases, which may make it difficult for the cam rod 3 to rotate to the closed position, or cause the side surface of the drill shaft 10 to deform. In the case where the lower plate 7 is provided, the displacement of the lower plate 7 in response to the magnitude of the pressure applied by the cam rod 3 to the upper plate 6 can rotate the cam rod 3 to the closed position with approximately the same force as when the diameter of the drill shaft 10 is smaller than the standard value, even if the diameter of the drill shaft 10 is larger than the standard value. 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 bend and displace.

The operating rod 3 further has a contact portion 3c that contacts other components mounted on the drill shaft 10 in the direction along the center axis O. As shown in FIG5 , when the operating rod 3 is in the open position, the contact portion 3c is disposed at a position facing the front end surface of the body 2 in the front-rear direction and spaced apart from the body 2 by a specific interval L in the front-rear direction, and faces the side opposite to the body 2. Therefore, by making the contact portion 3c contact the base end surface of the other component 12 when the operating rod 3 is in the open position, the interval between the component 12 and the body 2 can be adjusted to the specific interval L.

In one example, a convex portion 3e protruding from the upper surface 3d of the operating lever 3 is provided. The abutment portion 3c is formed by the side surface of the convex portion 3e on the base end side of the operating lever 3. The upper surface 3d of the operating lever 3 is a surface that is arranged on the upper side when the operating lever 3 is in a closed position. The angle formed by the upper surface 3d and the abutment portion 3c is preferably 90° or close to 90°. In this case, the interval between the component 12 and the body 2 can be adjusted by making the angle between the upper surface 3d and the abutment portion 3c contact the angle between the side surface and the base end surface of the component 12. The interval L is designed according to the thickness of the opposite cortical bone D2 and the specific protrusion amount when the front end of the drill shaft 10 protrudes from the outer surface of the opposite cortical bone D2. In one 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, the method of drilling a hole in a bone using a drill equipped with a drill stopper 1 is described with reference to FIG6 . FIG6 shows the step of drilling a hole in bone A for fixing the screw 20 to bone A by bicortical fixation in an operation in which a bone plate 21 is fixed to the outer surface of bone A by screws 20. Bone A is a tubular bone such as a tibia or a femur, and the soft spongiosa E on the inner side is covered by the hard cortical bone D on the outer side. 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 stopper 1 to the base end of the drill shaft 10, and installs the C-shaped ring 12 at a desired position between the front end of the drill shaft 10 and the drill 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 long side direction of the drill shaft 10 against the 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 the distance between the base end surface of the drill guide 11 and the drill stopper 1.

Next, in step S2, the operator operates the electric drill 13 to rotate the drill shaft 10, and uses the rotating drill shaft 10 to drill a hole from the outer surface of the proximal cortical bone D1 to the inner surface of the opposite cortical bone D2 on the bone A. During the drilling process on the bone A, after the C-shaped ring 12 abuts against the base end surface of the drill guide 11, the drill shaft 10 moves relative to the C-shaped ring 12. When the front end of the drill shaft 10 contacts the inner surface of the opposite cortical bone D2, the operator temporarily stops the rotation and advancement of the drill shaft 10. When the front end of the drill shaft 10 contacts the inner surface of the opposite cortical bone D2, the resistance against the advancement of the drill shaft 10 increases rapidly. The operator can recognize that the front end of the drill shaft 10 has contacted the inner surface of the opposite cortical bone D2 based on the increase in resistance transmitted to the hand holding the electric drill 13.

Next, in step S3, the operator rotates the operating rod 3 to the open position to release the fixation of the drill stopper 1 to the drill shaft 10. Then, after confirming that the C-shaped ring 12 abuts against the base end surface of the drill guide 11, the operator moves the drill stopper 1 to the side of the C-shaped ring 12 relative to the drill shaft 10 to position the drill stopper 1 at a position where the abutment portion 3c abuts against the base end surface of the C-shaped ring 12, and then rotates the operating rod 3 to the closed position to fix the drill stopper 1 to the drill shaft 10 again. Next, in step S4, the operator will start rotating and advancing 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 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 the drilling.

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

As described above, according to the present embodiment, when the protrusion amount of the front end of the drill shaft 10 from the outer surface of the opposite cortical bone D2 reaches a specific protrusion amount, the front end surface of the body 2 abuts against the base end surface of the C-shaped ring 12. Thus, the advancement of the drill shaft 10 is mechanically stopped, and the operator can also recognize that the front end of the drill shaft 10 has only protruded from the outer surface of the opposite cortical bone D2 by a specific protrusion amount. Thus, excessive perforation of the bone A can be prevented.

Furthermore, according to the present embodiment, the drill stopper 1 is directly fixed to the side surface of the drill shaft 10 by the friction between the plates 6, 7 and the drill shaft 10. Therefore, the drill stopper 1 can be used on various types of drills regardless of the type of the chuck of the electric drill 13, whether it is electric or manual, so that a drill stopper 1 with high versatility can be provided. Furthermore, since there is no restriction on the position where the drill stopper 1 is mounted on the drill shaft 10, the mounting position can be infinitely displaced in the long side direction of the drill shaft 10, so that the drill stopper 1 can be mounted at any position on the drill shaft 10.

In addition, according to the present embodiment, the drill stopper 1 fixes and releases the drill shaft 10 only by rotating the cam lever 3. In addition, the cam lever 3 can be rotated with a relatively small force while obtaining a relatively large fixing force applied by the body 2 to the drill shaft 10. Therefore, the operator can simply fix and release the drill stopper 1 by rotating the cam lever 3 using, for example, the thumb of one hand. 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, a fixing force of more than 150 N can be obtained.

Furthermore, according to the present embodiment, a lower plate 7 is provided below the drill shaft 10 in the through hole 2a, which is displaceable in the same manner as the upper plate 6. Thus, the drill stopper 1 can be securely 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 caused by the dimensional tolerance.

Furthermore, according to the present embodiment, by using the abutment portion 3c provided on the operating rod 3, the interval between the C-shaped ring 12 and the main body 2 can be adjusted to a specific interval accurately and simply. In addition, the rotation operation of the operating rod 3 and the movement of the main body 2 relative to the drill shaft 10 can be performed with only one hand. Therefore, while holding the electric drill 13 with one hand, the position of the drill stopper 1 relative to the C-shaped ring 12 can be adjusted with only the other hand. If the abutment portion 3c is not provided, it is necessary to measure the interval between the front end surface of the main body 2 and the base end surface of the C-shaped ring 12 by visual inspection or other devices, and then adjust the position of the drill stopper 1. Therefore, not only is the operation complicated, but it is also difficult to adjust the position of the drill stopper 1 with only the other hand.

In addition, according to this embodiment, since the main portion 5 of the body 2 and the plates 6, 7 are coaxially arranged with the drill shaft 10, and the operating rod 3 can be rotated in the front-rear direction, the axial diameter of the drill stopper 1 can be reduced. For example, the maximum outer diameter of the drill stopper 1 can be reduced to 15 mm. Thereby, the drill stopper 1 can be prevented 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, the drill stopper 1 can be prevented from interfering with other adjacent instruments.

In the above-mentioned 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 stopper 1 is preferably arranged on the inner side of the drill shaft 10 in the through hole 2a, and more preferably arranged on the long side axis (i.e., the center axis O) of the drill shaft 10 in the through hole 2a, or near the long side axis. According to this structure, by making the center of gravity G of the drill stopper 1 close to the center axis of the drill shaft 10, the vibration of the drill shaft 10 when the drill shaft 10 rotates can be reduced.

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

The recess 5b is preferably shaped to fit the operator's fingers. For example, when operating the drill stopper 1, the operator places the tip of the index finger extending in the left-right direction on the lower surface of the main body 5. Therefore, the recess 5b is preferably formed by a concave curved surface extending in the left-right direction. With this structure, the operator can hold the drill stopper 1 more firmly with his fingers, thereby improving operability.

In the above-mentioned embodiment, the operating lever 3 is opened and closed in the front-rear direction by rotating around the rotation axis P in the left-right direction, but the operating lever 3 may also be configured to be opened and closed in the left-right direction by rotating around the rotation axis P parallel to the center axis O as shown in FIGS. 8 to 9B . FIGS. 9A to 9B are front views of the drill stopper 1 viewed from the front end side along the direction of the axes O and P.

In another embodiment of Figures 8 to 9B, the main body 2 has a plate-shaped main portion 5 that is roughly semicircular, and an upper plate 6 that extends in the left-right direction. The right end 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 can be displaced in the up-down direction. By pressing the left end of the upper plate 6 by the cam rod 3, the upper plate 6 is pressed against the side surface of the drill shaft 10, thereby fixing the main body 2 to the drill shaft 10 in the through hole 2a. The lower part of the main portion 5 is provided with a recess 5b, whereby the center of gravity G of the entire drill stopper 1 is located on the inner side of the drill shaft 10 in the through hole 2a when the operating rod 3 is in the closed position. In this embodiment, a lower plate 7 which is not shown in the figure may also be provided.

In the above embodiment, although the operating lever 3 is a cam lever, the operating lever 3 may be an operating lever of other structures as long as the operating lever 3 can press the upper plate 6 by rotating to the closed position. If necessary, a fixing mechanism for temporarily fixing the operating lever 3 in the closed position may 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, other forms may be adopted as long as the pressing member and the adjusting member can be elastically displaced at least downward by the pressing force applied thereto by the operating lever 3. For example, the pressing member and the adjusting member can be members of any shape supported by the main part 5 via elastic members such as springs, or can be members that can be displaced by deformation of elastic members.

In the above-mentioned embodiment, the contact portion 3c is provided on the upper surface 3d at a position between the front end and the base end of the operating rod 3, but the structure of the contact portion is not limited thereto and can be appropriately modified. FIG. 10A to FIG. 11C show other structural examples of the contact portion. FIG. 10C to FIG. 11C show an example of use in which the contact portion 3c is contacted with the base end surface of the drill guide 11 which is another component 12.

In Fig. 10A to Fig. 10C, the base end of the operating rod 3 is provided with a convex portion 3f protruding from the upper surface 3d, and the abutment portion 3c is constituted by the base end surface (base end surface of the convex portion 3f) of the operating rod 3. 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 inserting the drill shaft 10 into the concave portion 3g, the operating rod 3 can be placed in an open position without interfering with the drill shaft 10, and the abutment portion 3c arranged at the front end side of the drill stopper 1 can abut against the component 12.

As shown in Figures 11A to 11C, the abutment portion 8a is provided on the main body 2 and can be displaced in the front-rear direction relative to the main 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 Figure 11C, a roughly cylindrical slit 2b for accommodating the elastic member is formed at the front end of the main body 2, which is formed coaxially with the center axis O on the radial outer side of the through hole 2a. In a natural state, the elastic member 8 protrudes from the front end surface of the main body 2, and after being compressed in the front-rear direction, the entire elastic member 8 can be accommodated in the slit 2b. The abutment portion 8a is formed by the front end surface of the elastic member 8. The abutment portion 8a may also be formed by other components fixed to the front end of the elastic component 8.

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

1: Drill stopper 2: Body 2a: Through hole 3: Operating lever, cam lever 3b: Cam surface 3c, 8a: Abutment 6: Upper plate (pressing member) 7: Lower plate (adjusting member) 10: Drill axis O: Center axis P: Rotation axis

FIG. 1 is a side view showing a drill stopper of an embodiment in use. FIG. 2 is a three-dimensional exploded view of the drill stopper of FIG. 1 . FIG. 3A is a longitudinal sectional view for explaining the function of the drill stopper of FIG. 1 , showing a state where the operating rod is in an open position. FIG. 3B is a longitudinal sectional view for explaining the function of the drill stopper of FIG. 1 , showing a state where the operating rod is in a closed position. FIG. 3C is a longitudinal sectional view for explaining the function of the drill stopper of FIG. 1 , showing a state where a drill shaft is arranged in a through hole and the operating rod is in a closed position. FIG. 4 is a side view of the front end portion of a cam rod provided with a cam surface. FIG. 5 is an explanatory diagram for the method of using the abutment portion of the operating rod. FIG. 6 is an explanatory diagram for the steps of drilling a bone by using a drill bit with the drill stopper of FIG. 1 mounted thereon. FIG. 7 is a front view for explaining the center of gravity position of the drill stopper of FIG. 1. FIG. 8 is a side view showing the use state of another embodiment of the drill stopper. FIG. 9A is a front view of the drill stopper of FIG. 8, showing the operating rod in an open position. FIG. 9B is a front view of the drill stopper of FIG. 8, showing the operating rod in a closed position. FIG. 10A is a three-dimensional view of a drill stopper showing a modification of the abutment portion, showing the operating rod in an open position. FIG. 10B is a perspective view of the drill stopper of FIG. 10A with the operating lever in the closed position. FIG. 10C is a side view illustrating the use of the contact portion of FIG. 10A and FIG. 10B. FIG. 11A is a side view of a drill stopper showing another variation of the contact portion, which is an explanatory view for the use of the contact portion. FIG. 11B is a view showing a state in which the main body is in contact with other components by compression of the elastic component. FIG. 11C is a perspective exploded view of the drill stopper of FIG. 11A and FIG. 11B. FIG. 12 is a view illustrating OWHTO.

without

1: Drill stopper

2: Body

2a: Through hole

3: Joystick, cam lever

3a,5a: Pin hole

3b: Cam surface

3c: abutment part

3d: upper surface

3e: convex part

4: Sales

5b: Concave part

6: Upper plate (pressing components)

6a,7a: Inner surface

7: Lower plate (adjustment component)

O: Center axis

Claims (9)

A drill stopper is mounted on the drill shaft of a surgical drill used for drilling a hole in a bone, and comprises: a body having a through hole for the drill shaft to pass through; a pressing member provided on the body and forming a part of the inner surface of the through hole and capable of displacement in the direction of the central axis of the through hole; and a lever having a cam surface at one end, the side of the one end being rotatably connected to the body around a predetermined rotation axis; the lever can rotate between a fixed position and a release position different from the fixed position; When the operating lever is arranged at the fixed position, the pressing member is pressed toward the center axis by the cam surface, so that the main body is fixed to the drill shaft. The drill stopper as described in claim 1 has a pin supported on the main body; The side of the one end of the operating rod is connected to the main body via the pin. A drill stopper as described in claim 1, wherein when the operating rod is arranged in the fixed position, the friction between the cam surface and the pressing member is used to prevent the operating rod from rotating toward the releasing position. A drill stopper as described in claim 1, wherein the pressing member is supported by the main body in a cantilever manner. A drill stopper as described in claim 1, wherein the pressing member is supported by the main body in a manner capable of elastic displacement at least in a direction toward the central axis. The drill stopper as described in claim 1 has an adjustment member disposed on the main 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 can be displaced to a direction away from the central axis. A drill stopper as described in any one of claims 1 to 6, wherein the cam surface rotates around the rotation axis while contacting the pressing member when rotating; The distance from the rotation axis to the contact point on the cam surface with the pressing member gradually increases as the operating lever rotates from the release position to the fixed position. A drill stopper as described in any one of claims 1 to 6, wherein the center of gravity of the drill stopper is arranged on the inner side of the drill shaft in the through hole. A drill stopper as described in claim 7, wherein the center of gravity of the drill stopper is arranged on the inner side of the drill shaft in the through hole.

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