Reamer chuck and reamer kit using the same

Abstract

Reduce the height of the reamer chuck device along the axis of rotation. [Solution] The reamer chuck 2, which connects a reamer and a shaft for rotationally driving the reamer, comprises a substantially cylindrical main body 21, a shaft insertion hole 22 recessed in the center of the shaft mounting surface 21a of the main body 21, a reamer engaging portion 23 protruding from the reamer mounting surface 21b of the main body 21, and a holding portion 24 that clamps the engaged portion of the reamer between itself and the reamer engaging portion 23. The holding portion 24 has a ball that protrudes and retracts from the reamer mounting surface 21b, and a spring that biases the ball in the protruding direction, and the spring is housed in the main body 21 at a position adjacent to the shaft insertion hole 22. With this configuration, since the spring and the shaft insertion hole 22 are not aligned vertically along the rotation axis Ax, the height of the reamer chuck 2 along the rotation axis Ax can be reduced.

Description

Technical Field

[0001] The present invention relates to a reamer chuck for connecting a reamer and a shaft for rotationally driving the same, and a reamer kit using the same.

Background Art

[0002] In diseases such as osteoarthritis and osteonecrosis of the femoral head, surgery may be performed to replace the damaged hip joint with an artificial hip joint. In such surgery, generally, a cup is attached to the acetabulum, and the femoral head prosthesis is fitted into the cup via a liner that substitutes for cartilage. The cup is attached to a recess in the acetabulum formed to fit the outer surface of the cup by cutting the acetabulum using a hemispherical blade called a reamer.

[0003] The reamer is connected to the shaft via a reamer chuck. The reamer chuck is, for example, substantially cylindrical, with a reamer engagement portion provided on one end face and a shaft insertion port for inserting the shaft being recessed at the center of the other end face. The reamer engagement portion is, for example, composed of a plate provided with a cross groove that fits into the cross bar of the reamer, and this plate locks the cross bar by being biased toward the reamer by a spring disposed at the center of the reamer chuck (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the reamer chuck as described above, the spring that biases the plate and the shaft insertion port are arranged vertically along the rotation axis of the reamer. Therefore, the device height of the reamer chuck along the rotation axis becomes large.

[0006] The present invention aims to solve the above problems and to provide a reamer chuck with a reduced device height along the rotation axis. [Means for solving the problem]

[0007] The present invention relates to a reamer chuck that connects a reamer and a shaft for rotationally driving the reamer, circle The columnar main body and the center of the shaft mounting surface that forms one end face of the main body. From along the axis of rotation of the reamer A recessed shaft insertion hole, a reamer engagement portion protruding from the reamer mounting surface forming the other end face of the main body, and a holding portion that clamps the engaged portion of the reamer between the reamer engagement portion and the holding portion, The main body portion includes a through hole provided parallel to the rotation axis, The holding portion comprises the A spring inserted parallel to the rotation axis into the through hole, and a ball fixed to the end of the spring on the reamer mounting surface side, It has, When the spring is not compressed, a portion of the ball protrudes from the reamer mounting surface, and when the spring is compressed, it retracts from the reamer mounting surface and is retracted into the through hole. The spring is characterized in that it is housed in the main body at a position adjacent to the shaft insertion hole. ru.

[0008] The aforementioned through hole It penetrates from the shaft mounting surface of the main body to the reamer mounting surface. death It is preferable that this is the case.

[0009] The reamer engaging portion has a plurality of upright portions erected from the periphery of the reamer mounting surface, and a plurality of claw portions extending from the tip of each of the plurality of upright portions along the circumferential direction of the main body, and it is preferable that the engaged portion of the reamer is clamped by the ball protruding from the reamer mounting surface, the upright portions, and the claw portions.

[0010] The shaft insertion hole is, in plan view And many It is preferable that the shape is rectangular and has an enlarged section with rounded corners.

[0011] Reamer of the present invention kitIt is characterized by including the above-mentioned reamer chuck, a reamer engaged with the reamer chuck, and a shaft attached to the reamer chuck for rotationally driving the reamer.

Advantages of the Invention

[0012] According to the present invention, since the spring of the holding portion and the shaft insertion hole are not vertically arranged along the rotation axis, the device height of the reamer chuck along the rotation axis can be reduced.

Brief Description of the Drawings

[0013] [Figure 1] (a) and (b) are an exploded perspective view and a perspective view of a reamer kit according to an embodiment of the present invention. [Figure 2] (a) and (b) are perspective views of the reamer chuck constituting the reamer kit. [Figure 3] A plan view of the reamer chuck. [Figure 4] A side sectional view of the reamer chuck. [Figure 5] (a)-(d) are side views showing the engagement process between the reamer chuck and the reamer. [Figure 6] (a)-(c) are side sectional views showing the operation when cutting the acetabulum using the reamer kit. [Figure 7] (a)-(c) are side sectional views showing the operation when cutting the acetabulum using a conventional reamer kit.

Embodiments for Carrying Out the Invention

[0014] The reamer kit according to an embodiment of the present invention will be described with reference to the drawings. As shown in FIGS. 1(a) and (b), the reamer kit 1 includes a reamer chuck 2, a reamer 3 engaged with the reamer chuck 2, and a shaft 4 attached to the reamer chuck 2 for rotationally driving the reamer 3.

[0015] The burr 3 is configured by an acetabular burr for cutting bone by rotation, and in the illustrated example, it cuts the acetabulum. The burr 3 is made of, for example, stainless steel, titanium alloy, cobalt-chromium alloy, nitinol (nickel-titanium alloy), etc., and has a hemispherical portion 31 formed in a hemispherical shape, and an engaged portion 32 attached so as to line the hemispherical surface of the hemispherical portion 31. The hemispherical portion 31 has a plurality of cutting teeth 31a on its outer surface, and these cutting teeth 31a cut the acetabulum when rotated around the rotation axis Ax. The engaged portion 32 is composed of two round bars 32a and 32b provided along the diameter of the hemispherical portion 31. The round bars 32a and 32b have the same shape and are arranged so as to be orthogonal to each other and cross-shaped.

[0016] The shaft 4 is formed in a long bar shape and has a connecting end 41 connected to the burr chuck 2 at one end (the lower end in the illustrated example). The connecting end 41 is formed in a quadrangular prism shape in the illustrated example. The other end (the upper end in the illustrated example) of the shaft 4 is a driving end 42 connected to an electric driver (not shown) for rotating the shaft 4 around the rotation axis Ax. The shaft 4 is made of the same material as the burr 3.

[0017] As shown in FIGS. 2(a) and 2(b), the burr chuck 2 has a substantially cylindrical main body portion 21, a shaft insertion hole 22 into which the shaft 4 is inserted, a burr engaging portion 23 for engaging with the engaged portion 32 of the burr 3, a holding portion 24 for holding the state in which the burr engaging portion 23 is engaged with the engaged portion 32, and a gripping portion 25 that serves as a handle when gripping the burr chuck 2 with a finger. The burr chuck 2 is also made of the same material as the burr 3.

[0018] The shaft insertion hole 22 is provided in a shaft mounting surface 21a (see FIG. 2(a)) that forms one end surface (the upper surface in the illustrated example) of the main body portion 21. The shaft insertion hole 22 is composed of a square hole recessed along the rotation axis Ax from the center of the shaft mounting surface 21a and conforms to the outer surface of the connecting end 41 inserted into the shaft insertion hole 22. The shaft 4 is detachably attached to the shaft insertion hole 22.

[0019] The reamer engaging portion 23 is provided as a protrusion on the reamer mounting surface 21b which forms the other end surface (bottom surface in the illustrated example) of the main body portion 21, and has a plurality of upright portions 23a erected parallel to the rotation axis Ax from the periphery of the reamer mounting surface 21b, and a plurality of claw portions 23b extending in the same direction along the circumferential direction C of the main body portion 21 from each tip of the plurality of upright portions 23a. In the illustrated example, there are four upright portions 23a provided at equal intervals from each other (at angles of 90 degrees each). The claw portions 23b are formed in a thin plate shape that extends opposite to the reamer mounting surface 21b.

[0020] A gap G is formed between the first claw portion 23b and the adjacent upright portion 23a that faces the tip of the claw portion 23b, allowing the round bar 32a or 32b to pass through. Furthermore, the side of the upright portion 23a on which the claw portion 23b is formed has a curved surface (contact surface) 23c that fits the outer surface of the round bar 32a or 32b.

[0021] In the illustrated example, four holding portions 24 are arranged at equal intervals from each other, facing the tip of the claw portion 23b. These holding portions 24 are fitted into through holes 21c provided in the main body portion 21. The through holes 21c penetrate from the shaft mounting surface 21a to the reamer mounting surface 21b, parallel to the rotation axis Ax. In the illustrated example, the gripping portions 25 are provided between adjacent holding portions 24 and are formed by recesses provided on the side surface of the main body portion 21.

[0022] As shown in Figure 3, the shaft insertion hole 22 (indicated by a dot) is roughly polygonal in plan view (roughly quadrilateral in the example shown), and has an enlarged portion 22a at each corner. The enlarged portion 22a has a rounded shape that expands outward and extends from the shaft mounting surface 21a to the bottom of the shaft insertion hole 22.

[0023] As shown in Figure 4, each holding part 24 is composed of a ball plunger having a spring 24a inserted into a through hole 21c parallel to the rotation axis Ax, a ball 24b fixed to the end of the spring 24a on the reamer mounting surface 21b side, and a set screw 24c fixed to the end of the spring 24a on the shaft mounting surface 21a side.

[0024] The spring 24a is housed in the main body 21 at a position adjacent to the shaft insertion hole 22. The ball 24b, biased by the spring 24a in the direction of the reamer mounting surface 21b (protruding direction), partially protrudes from the reamer mounting surface 21b when the spring 24a is not compressed, and retracts from the reamer mounting surface 21b and is retracted into the through hole 21c when the spring 24a is compressed. In the illustrated example, the set screw 24c has a hexagonal socket 24d and is screwed into a thread (not shown) provided on the inner circumference of the through hole 21c.

[0025] This configuration allows the retaining part 24 to be screwed in from the shaft mounting surface 21a side, making assembly during manufacturing easier. In addition, by inserting a hex wrench into the hex socket 24d and moving the set screw 24c back and forth within the through hole 21c, the degree to which the ball 24b protrudes from the reamer mounting surface 21b can be adjusted.

[0026] Next, with reference to Figures 5(a)-(d), the operation for engaging the engaged portion 32 with the reamer engaging portion 23 will be described. First, as shown in Figure 5(a), while holding the reamer chuck 2 by grasping the gripping portion 25 with your fingers, pass the engaged portion 32 (round bar 32a or 32b) through the gap G, and bring the engaged portion 32 into contact with the reamer mounting surface 21b, as shown in Figure 5(b). At this time, the ball 24b (shown by a dot) protruding from the reamer mounting surface 21b is positioned adjacent to the engaged portion 32.

[0027] Next, as shown in Figure 5(c), the reamer 3 (not shown) is rotated relative to the reamer chuck 2, and the engaged portion 32 is slid into the space between the reamer mounting surface 21b and the claw portion 23b. As a result, the ball 24b retracts into the through hole 21c against the biasing force of the spring 24a by contacting the engaged portion 32. Then, as shown in Figure 5(d), when the engaged portion 32 contacts the contact surface 23c, a portion of the ball 24b protrudes from the reamer mounting surface 21b again due to the biasing force of the spring 24a, and the engaged portion 32 is clamped between the reamer mounting surface 21b, the ball 24b protruding from the reamer mounting surface 21b, the contact surface 23c (upright portion 23a), and the claw portion 23b.

[0028] To remove the reamer 3 from the reamer chuck 2, simply reverse the above steps. This will make the reamer chuck 2 detachably attached to the reamer 3.

[0029] Next, referring to Figures 6(a)-(c), the procedure for cutting the acetabulum B using the reamer kit 1 will be described. First, as shown in Figure 6(a), the shaft 4 is removed from the reamer chuck 2, and the reamer 3, which is engaged with the reamer chuck 2, is inserted onto the acetabulum B from the side of the muscle M (subportal approach). Then, as shown in Figure 6(b), the shaft 4, which has percutaneously penetrated the muscle M, is inserted into the shaft insertion hole 22 of the reamer chuck 2, and the reamer 3 is rotated by rotating the shaft 4 with an electric screwdriver (not shown) to cut the acetabulum B. At this time, since an enlarged portion 22a is provided in the shaft insertion hole 22, the shaft 4 is easily guided into the shaft insertion hole 22.

[0030] Then, as shown in Figure 6(c), after cutting the acetabulum B to the desired shape, the shaft 4 is removed from the reamer chuck 2, and the shaft 4 is pulled out through the hole H made in the muscle M, while the reamer chuck 2 and reamer 3 are removed from the side of the muscle M. In this case, the hole H made in the muscle M is small, corresponding to the thickness of the shaft 4, so the damage to the muscle M is small and the time required for healing is also shortened.

[0031] In contrast, as shown in Figures 7(a)-(c), when using a conventional reamer kit 1 in which the shaft 4 cannot be removed from the reamer chuck 2, it is necessary to drill a large hole H in the muscle M corresponding to the diameter of the reamer 3. This results in greater damage to the muscle M and a longer healing time.

[0032] As described above, with the reamer chuck 2, the spring 24a of the holding part 24 is adjacent to the shaft insertion hole 22 in a direction perpendicular to the rotation axis Ax, and the spring 24a and the shaft insertion hole 22 are not aligned vertically along the rotation axis Ax. Therefore, the device height of the reamer chuck 2 along the rotation axis Ax can be reduced. As a result, the device height of the reamer 3 engaged with the reamer chuck 2 is also reduced, making it easier to insert the reamer chuck 2 and reamer 3 through a narrow gap from the side of the muscle M, as shown in Figures 6(a)-(c).

[0033] It should be noted that the reamer chuck and reamer kit according to the present invention are not limited to the above embodiments and can be modified in various ways. For example, the number of jaws and holding parts is not limited to four, but may be two, three, or five or more. Also, the shaft insertion hole does not necessarily need to have an enlarged portion and may be configured without one. [Explanation of Symbols]

[0034] 1 Reamer Kit 2 Reamer Chuck 21 Main body 21a Shaft mounting surface 21b Reamer mounting surface 21c through hole 22 shaft insertion holes 22a Enlarged section 23 Reamer engagement part 23a Standing section 23b Claw part 24 Holding part 24a Spring 24b Ball 3 Reamer 32 Engaged portion 4 shafts C (Circumferential direction of the main body)

Claims

1. A reamer chuck that connects a reamer and a shaft for rotationally driving the reamer, The device comprises a cylindrical main body, a shaft insertion hole recessed from the center of the shaft mounting surface forming one end face of the main body along the rotation axis of the reamer, a reamer engagement portion protruding from the reamer mounting surface forming the other end face of the main body, a holding portion that clamps the engaged portion of the reamer between itself and the reamer engagement portion, and a through hole provided in the main body parallel to the rotation axis. The holding portion includes a spring inserted into the through hole parallel to the rotation axis, and a ball fixed to the end of the spring on the reamer mounting surface side. When the spring is not compressed, a portion of the ball protrudes from the reamer mounting surface, and when the spring is compressed, it retracts from the reamer mounting surface and is retracted into the through hole. The reamer chuck is characterized in that the spring is housed in the main body at a position adjacent to the shaft insertion hole.

2. The reamer chuck according to claim 1, characterized in that the through hole penetrates from the shaft mounting surface of the main body to the reamer mounting surface.

3. The reamer engaging portion has a plurality of upright portions erected from the periphery of the reamer mounting surface, and a plurality of claw portions extending from each tip of the plurality of upright portions along the circumferential direction of the main body, The reamer chuck according to claim 1, characterized in that the engaged portion of the reamer is held by the ball, the upright portion, and the claw portion protruding from the reamer mounting surface.

4. The reamer chuck according to claim 1, characterized in that the shaft insertion hole is polygonal in plan view and has an enlarged portion with rounded corners.

5. A reamer kit comprising a reamer chuck according to any one of claims 1 to 4, a reamer that engages with the reamer chuck, and a shaft attached to the reamer chuck for rotationally driving the reamer.

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