An adjustable-angle bone milling cutter

Abstract

The present invention relates to the technical field of medical devices, and discloses an angle-adjustable bone milling cutter, comprising: a milling cutter, a main shaft, a protective boot and an angle adjustment assembly. The milling cutter of the present invention is movably connected to the main shaft through a universal joint, and the main shaft transmits cutting power to the milling cutter through a power handle; the protective boot is rotatably connected to the housing and is driven and limited by a driven member. The driven member is pushed to move through an adjustment cylinder and reset by a spring. When it is necessary to adjust the angle of the milling cutter, the user can rotate the adjustment cylinder to push the driven member to move. The movement of the driven member pushes the protective boot to rotate around the rotary ball head on the housing, and the rotation of the protective boot drives the milling cutter connected thereto to rotate around the universal joint by a certain angle, thereby realizing the adjustment of the working angle of the milling cutter; the bone milling cutter of the present invention does not need to move a large range or take out the entire milling cutter for direction and angle adjustment, which can reduce the adjustment difficulty, save the operation time and improve the milling effect.

Description

Technical Field

[0001] The present invention relates to the technical field of medical devices, and particularly to an adjustable-angle bone milling cutter. Background Art

[0002] In the fields of orthopedics or related surgical operations such as the spine, knee, and neurosurgery, bone cutting milling cutters are usually used to mill the lamina, cranial plate, or other bone tissues. Only when the cutter head of the milling cutter and the bone tissue are kept as perpendicular as possible can the milling effect reach the best. In the prior art, there are Chinese patents for a flushing cranial milling cutter (publication number: CN220558062U) and a sheath for a bone cutting milling cutter and a medical milling tool (publication number: CN218484617U). Although the disclosed cranial milling cutter and medical milling tool can improve the milling effect, the cutter head of the milling cutter is fixed and cannot be adjusted according to the shape and structure of the bone tissue. Usually, the whole milling cutter needs to be taken out, adjusted in direction and angle, and then reinserted, or the whole milling cutter needs to be adjusted over a large range without being taken out, which is inconvenient to operate in a narrow surgical cavity or a complex surgical environment, increasing the surgical difficulty and time. Moreover, if the bone tissue is not in the shape of a regular flat plate, the cutter head cannot always be perpendicular to the tissue, and the milling effect will be further reduced. Summary of the Invention

[0003] The present invention provides an adjustable-angle bone milling cutter to solve the problem that the existing orthopedic milling cutter cannot be conveniently adjusted in angle during the operation.

[0004] An adjustable-angle bone milling cutter includes: a milling cutter, a main shaft, a protective boot, and an angle adjustment assembly;

[0005] The milling cutter includes a cutter head, a cutting edge, and a cutter tail. The cutter tail is drivingly connected to the main shaft through a universal joint, and the cutter head is clamped with the protective boot, so that the milling cutter can rotate by the rotation of the protective boot;

[0006] An angle adjustment assembly is arranged outside the main shaft. The angle adjustment assembly includes a driven member, a spring, an adjustment cylinder, and a housing;

[0007] The driven member is rotationally matched with the protective boot and limited by the housing. The driven member is driven to move through the adjustment cylinder and reset by the spring.

[0008] Further, the main shaft includes a shaft head, a tail shaft body, and a middle step located between the shaft head and the tail shaft body;

[0009] Bearings are sleeved on the outer walls of the shaft head and the tail shaft body;

[0010] A spacer sleeve is sleeved outside the middle step. The spacer sleeve is limited by bearings at both ends. An outer bearing sleeve is sleeved outside the spacer sleeve. The driven member is slidably arranged on the outer wall of the outer bearing sleeve.

[0011] Furthermore, the bearing outer sleeve includes a first step, a second step, and a third step with gradually increasing heights. An external thread is provided on the outer wall of the second step, and an internal thread is provided on the inner wall of the third step;

[0012] A limiting plane is provided on the wall surface of the first step, and a connecting and fixing inner hole along the radial direction is provided on the limiting plane.

[0013] Furthermore, the follower includes an integrally formed sliding cylinder and a Z-shaped rod. The Z-shaped rod is located at the end face of the sliding cylinder, and a circular hole is provided at the head of the Z-shaped rod.

[0014] Furthermore, the protective boot includes a boot head, a boot rod, and a boot body. The two ends of the boot rod are respectively connected to the boot head and the boot body;

[0015] A jack is provided on the boot head, and the tool bit is inserted into the jack;

[0016] The boot body is in an arc-shaped block, and a card slot and a ball head slot are provided thereon. A pin hole is provided on the slot wall of the card slot, and the pin hole corresponds to the circular hole. The protective boot rotates around the connecting pin by inserting a connecting pin into the pin hole and the circular hole.

[0017] Furthermore, the above-mentioned housing is in a cylindrical shape, a rotating ball head is provided on the end face of one end thereof, and at the same time, an axially avoiding groove is provided on its side wall. The head of the Z-shaped rod of the follower is located in the avoiding groove;

[0018] The rotating ball head is inserted into the ball head slot and is rotationally matched with the boot body;

[0019] An internal step is provided on the inner wall of one end of the housing, and a connecting and fixing outer hole is provided on the internal step. The position and size of the connecting and fixing outer hole correspond to those of the connecting and fixing inner hole.

[0020] Furthermore, the handle mounting portion includes a connecting shaft sleeve, an inner housing, and a locking ring. The connecting shaft sleeve is sleeved and connected to the outer wall of the main shaft. The inner housing is arranged outside the connecting shaft sleeve and is threadedly connected to the bearing outer sleeve. The locking ring is arranged outside the inner housing.

[0021] Furthermore, a plurality of through holes are also provided on the side wall of the inner housing, and steel balls are arranged in the through holes to clamp the power handle through the steel balls.

[0022] Furthermore, the universal joint includes a front shaft sleeve and a rear shaft sleeve. A clamping hole is provided on the side wall of the front shaft sleeve. The tool tail is inserted into the front shaft sleeve and is fixed by inserting a clamping column into the clamping hole.

[0023] Furthermore, an arc-shaped groove and a key groove are also provided on the front shaft sleeve;

[0024] An extended section of the key groove is also provided on the rear shaft sleeve. A connecting key is arranged in the key groove and the extended section of the key groove. The connecting key is rotationally connected to the front shaft sleeve through a pin rod;

[0025] The main shaft is inserted inside the rear bushing. There are convex spherical blocks arranged on the rear bushing. The convex spherical blocks are inserted into the arc-shaped grooves and are rotatably arranged.

[0026] The present invention has the following beneficial effects:

[0027] (1) The milling cutter of the present invention is movably connected to the main shaft through a universal joint. The main shaft is detachably connected to the power handle through the handle mounting part, thereby transmitting cutting power to the milling cutter. The protective boot is rotatably connected to the housing and is driven and limited by the driven member. The driven member is pushed to move through the adjusting cylinder and reset by the spring. When the angle of the milling cutter needs to be adjusted, the user can rotate the adjusting cylinder to push the driven member forward. The movement of the driven member pushes the protective boot to rotate around the rotating ball head on the housing. The rotation of the protective boot drives the milling cutter connected thereto to rotate a certain angle around the universal joint, thereby realizing the adjustment of the working angle of the milling cutter. When the angle of the milling cutter needs to be adjusted in the reverse direction, only need to rotate the adjusting cylinder in the reverse direction, and the driven member can be pushed backward by the resilience of the spring. The bone milling cutter of the present invention does not need to move a large range or take out the whole milling cutter for adjusting the direction and angle, which can reduce the adjustment difficulty, save the operation time and improve the milling effect.

[0028] (2) The angle adjustment of the milling cutter of the present invention is highly accurate. The adjustment angle of the milling cutter is determined by the rotation amplitude of the protective boot. The rotation amplitude of the protective boot is determined by the moving distance of the driven member. And the moving distance of the driven member is determined by the axial moving length of the adjusting cylinder. The adjusting cylinder and the bearing outer sleeve are connected by threads. When the adjusting cylinder rotates one week, the rotation amplitude of the protective boot is very subtle, avoiding the large-amplitude rotation of the milling cutter, which is beneficial to improving the accuracy during the operation, and all components adopt mechanical transmission, which is stable and reliable. Description of the Drawings

[0029] Figure 1 It is a schematic diagram of the external structure of the whole bone milling cutter of the present invention;

[0030] Figure 2 It is a schematic cross-sectional view of the bone milling cutter of the present invention along the central axis;

[0031] Figure 3 It is a schematic diagram of the internal structure of the bone milling cutter of the present invention after hiding the housing, the adjusting cylinder and the locking ring;

[0032] Figure 4 It is a schematic diagram of the connection between the milling cutter and the universal joint in the present invention;

[0033] Figure 5 It is a schematic diagram of the structure of the milling cutter in the present invention;

[0034] Figure 6 It is a schematic diagram of the structure of the front bushing in the present invention;

[0035] Figure 7 Schematic structural diagram of the rear axle sleeve in the present invention;

[0036] Figure 8 Schematic structural diagram of the main shaft in the present invention;

[0037] Figure 9 Schematic structural diagram of the connecting sleeve in the present invention;

[0038] Figure 10 Schematic structural diagram of the spacer sleeve in the present invention;

[0039] Figure 11 Schematic structural diagram of the outer bearing sleeve in the present invention Figure 1 ;

[0040] Figure 12 Schematic structural diagram of the outer bearing sleeve in the present invention Figure 2 ;

[0041] Figure 13 Schematic structural diagram of the driven part in the present invention;

[0042] Figure 14 Schematic structural diagram of the protective boot in the present invention;

[0043] Figure 15 Schematic structural diagram of the outer shell in the present invention Figure 1 ;

[0044] Figure 16 Schematic structural diagram of the outer shell in the present invention Figure 2 ;

[0045] Figure 17 Schematic structural diagram of the inner shell in the present invention Figure 1 ;

[0046] Figure 18 Schematic structural diagram of the inner shell in the present invention Figure 2 ;

[0047] Figure 19 Schematic structural diagram of the adjusting cylinder in the present invention;

[0048] Figure 20 Schematic structural diagram of the locking ring in the present invention.

[0049] In the figure: 1 - milling cutter; 101 - cutter head; 102 - cutting edge; 103 - cutter tail; 104 - clamping post; 2 - main shaft; 201 - shaft head; 202 - tail shaft body; 203 - middle step; 204 - radial hole; 205 - dowel pin; 3 - connecting bushing; 4 - bearing; 5 - spacer sleeve; 6 - bearing outer sleeve; 601 - internal thread; 602 - external thread; 603 - first step; 604 - second step; 605 - third step; 606 - connecting and fixing internal hole; 607 - limiting plane; 7 - follower; 701 - sliding cylinder; 702 - Z-shaped rod; 8 - spring; 9 - adjusting cylinder; 10 - outer shell; 1001 - rotating ball head; 1002 - internal step; 1003 - avoiding slot; 1004 - connecting and fixing external hole; 11 - protective boot; 1101 - boot head; 1102 - boot rod; 1103 - boot body; 1104 - clamping slot; 1105 - pin hole; 1106 - connecting pin; 1107 - ball head slot; 12 - inner shell; 1201 - concave ring; 1202 - butt joint thread; 1203 - sealing ring; 1204 - through hole; 13 - locking ring; 14 - universal joint; 1401 - front bushing; 1402 - rear bushing; 1403 - arc-shaped groove; 1404 - convex ball block; 1405 - keyway; 1406 - connecting key; 1407 - pin rod; 1408 - clamping hole. Detailed implementation manner

[0050] The principles and features of the present invention will be described below in conjunction with the accompanying drawings. The examples given are only used to explain the present invention and are not intended to limit the scope of the present invention.

[0051] Refer to Figures 1 to 3 As shown in the figure, the present invention provides an adjustable-angle bone milling cutter, including: a milling cutter 1, a main shaft 2, a bearing outer sleeve 6, a protective boot 11, a handle mounting part, and an angle adjustment component. The milling cutter 1 is used for cutting bone tissue during surgery; the main shaft 2 is used to provide power for the rotation and movement of the milling cutter 1 to drive the milling cutter 1 to operate; the protective boot 11 is used to adjust the deflection angle of the milling cutter 1 so that the milling cutter 1 is always perpendicular to the bone tissue; the handle mounting part is used to connect with a power handle (not shown in the figure), and the power handle outputs rotational power to drive the main shaft 2 to operate; the angle adjustment component is used to assist the protective boot 11 to adjust the deflection angle and movement of the milling cutter 1.

[0052] Refer to Figure 4 And Figure 5, the milling cutter 1 includes a cutter head 101, a cutting edge 102 and a cutter tail 103. The cutter head 101 is inserted into the boot head 1101 of the protective boot 11, and its shape is adapted to the boot head 1101 and can rotate relative to the boot head 1101. For example, the cutter head 101 is set as a cylindrical shape; the cutting edge 102 includes multiple cutting surfaces and is evenly distributed on the cutter body. The size of the part where the cutter body is located is larger than that of the cutter head 101; the cutter tail 103 is cylindrical. One end is fixedly connected to the cutter body, and a U-shaped groove is opened at the other end on the end face. At the same time, a ring groove is opened in the middle of the cutter tail 103. The cutter tail 103 is coaxially driven and connected to the main shaft 2 through a universal joint 14, thereby driving the milling cutter 1 to rotate. The ring groove in the middle of the cutter tail 103 is used to cooperate with the clamping column 104 to firmly connect the cutter tail 103 to the universal joint 14.

[0053] Reference Figure 6 With Figure 7 , the universal joint 14 includes a front bushing 1401 and a rear bushing 1402.

[0054] Among them, the front bushing 1401 is integrally cylindrical, hollow inside, and a clamping hole 1408 is opened on the side wall. The clamping hole 1408 penetrates the outer wall and the inner wall and is opened radially. The clamping hole 1408 includes four that are evenly distributed in a circle, corresponding to the ring groove in the middle of the cutter tail 103. The cutter tail 103 is inserted into the front bushing 1401, and by inserting the clamping column 104 into the clamping hole 1408, the clamping column 104 connects and fixes the front bushing 1401 and the cutter tail 103. One end of the front bushing 1401 away from the cutter head 101 is also provided with an arc-shaped groove 1403 and a keyway 1405; the keyway 1405 is axially opened and distributed along the front bushing 1401, and the arc-shaped groove 1403 is distributed on the end face wall of the front bushing 1401. The arc-shaped groove 1403 includes two that are axially symmetrically distributed.

[0055] The rear shaft sleeve 1402 is also in a hollow columnar structure. On one end face, there are two protruding convex spherical blocks 1404. The position and shape of the convex spherical blocks 1404 are adapted to the arc-shaped grooves 1403. The convex spherical blocks 1404 are inserted into the arc-shaped grooves 1403 so that the front shaft sleeve 1401 and the rear shaft sleeve 1402 can rotate relative to each other within a certain angle range. An extension of the key groove 1405 is also provided on the outer side wall of the rear shaft sleeve 1402. The width of the key groove of this extension is the same as that of the key groove 1405 on the front shaft sleeve 1401. At the same time, the key groove of this extension does not penetrate the side wall of the rear shaft sleeve 1402 in the radial direction. By installing the same connecting key 1406 in the key groove 1405 of the front shaft sleeve 1401 and the extension of the key groove 1405 of the rear shaft sleeve 1402, power can be transmitted in the circumferential direction. The main shaft 2 is inserted into the rear shaft sleeve 1402. Since the key groove 1405 on the front shaft sleeve 1401 penetrates its side wall, and small holes are opened on both sides of the groove wall of the key groove 1405, and holes are also opened on the connecting key 1406. By passing a pin rod 1407 through the small holes in the groove wall of the key groove 1405 and the holes on the connecting key 1406, the front shaft sleeve 1401 can rotate around the pin rod 1407, thereby driving the milling cutter 1 to rotate within a certain angle, achieving the purpose of adjusting the angle of the milling cutter 1. In this embodiment, the milling cutter 1 can be adjusted within the working angle range of 0 to 30°. If a larger angle adjustment is required, the dimensional ratios of the various components of the milling cutter 1 need to be adjusted accordingly to achieve it.

[0056] Reference Figure 8 With Figure 10 , the main shaft 2 includes a shaft head 201, a tail shaft body 202, and a middle step 203 located between the shaft head 201 and the tail shaft body 202. The shaft head 201 is set as an arc-shaped sphere, passes through the hollow interior of the rear shaft sleeve 1402, and its spherical head is located inside the convex spherical block 1404 of the rear shaft sleeve 1402. The two are concentrically arranged. When the front shaft sleeve 1401 rotates, the shaft head 201 does not affect its rotation; a handle mounting part is connected to the tail shaft body 202; the diameter of the middle step 203 is larger than the diameters of the segments where the shaft head 201 and the tail shaft body 202 are located. Bearings 4 are sleeved on the outer walls of the shaft head 201 and the tail shaft body 202. By sleeving a spacer sleeve 5 outside the middle step 203, it is convenient to set a bearing outer sleeve 6 outside the main shaft 2. The spacer sleeve 5 is limited by the bearings 4 at both ends. The spacer sleeve 5 is a hollow circular tube with equal thickness and equal diameter. The driven member 7 is slidably arranged on the outer wall of the bearing outer sleeve 6.

[0057] Reference Figure 11 With Figure 12, the bearing outer sleeve 6 is integrally cylindrical. Its outer wall includes a first step 603, a second step 604, and a third step 605 with increasing heights in sequence. An external thread 602 is provided on the outer wall of the second step 604, and the external thread 602 is close to the first step 603 side. An internal thread 601 is provided on the inner wall of the third step 605; at the same time, an internal step is also provided in the hollow interior of the bearing outer sleeve 6. The internal step close to the first step 603 side is clamped on the protruding end face of the rear shaft sleeve 1402, and the protruding end face of the rear shaft sleeve 1402 is clamped on the end face of the bearing 4. The internal step close to the tail shaft body 202 side of the main shaft 2 is flush with the outer end face of the bearing 4 on this side, and the internal thread 601 on the inner wall of the third step 605 is located outside this side internal step. A limiting plane 607 is provided on the wall surface of the first step 603, and a radially connecting and fixing inner hole 606 is provided on the limiting plane 607.

[0058] An angle adjustment assembly is provided outside the bearing outer sleeve 6. The angle adjustment assembly includes a follower 7, a spring 8, an adjustment cylinder 9, and a housing 10.

[0059] Reference Figure 13 , a follower 7 is slidably sleeved on the first step 603 of the bearing outer sleeve 6. The follower 7 includes an integrally formed sliding cylinder 701 and a Z-shaped rod 702. One end of the Z-shaped rod 702 is connected to the end face of the sliding cylinder 701, and a circular hole is provided at the head of the other end of the Z-shaped rod 702. A spring 8 is sleeved on the concave part of the Z-shaped rod 702. One end of the spring 8 abuts against the side surface of the sliding cylinder 701, and the other end is movably connected to the Z-shaped bending part of the Z-shaped rod 702.

[0060] Reference Figure 19 , the adjustment cylinder 9 is a cylinder with an inner step and an inner wall thread. Its inner step is clamped on the second step 604 of the bearing outer sleeve 6. At the same time, the inner wall thread is adapted to the external thread 602 on the second step 604 and forms a threaded connection. The end face of the adjustment cylinder 9 is in contact with the end face of the sliding cylinder 701 of the follower 7; when the adjustment cylinder 9 is rotated, the follower 7 can be pushed to move towards the milling cutter 1 side. At this time, the spring 8 is compressed. When the adjustment cylinder 9 is rotated to move away from the milling cutter 1 side, the follower 7 moves backward under the elastic force of the spring 8.

[0061] Reference Figure 15 With Figure 16, The outer shell 10 is sleeved outside the spring 8. It is generally cylindrical in shape. The outer wall of the adjusting cylinder 9 is in contact with the inner wall of the outer shell 10 and can slide relative to each other without affecting the movement of the adjusting cylinder 9. On one end face of the outer shell 10 close to the milling cutter 1, there are protruding rotating ball heads 1001. There are two rotating ball heads 1001 and they are arranged axially symmetrically. At the same time, on the side wall of this side, there is an axially arranged avoiding groove 1003. The head of the Z-shaped rod 702 of the follower 7 is located in the avoiding groove 1003, playing a role in limiting and preventing the protective boot 11 from rotating circumferentially. On the inner wall of the outer shell 10, there is an inner step 1002. The inner step 1002 also has a plane corresponding to the limiting plane 607. At the same time, on this plane, there is a connecting and fixing outer hole 1004. The position and size of the connecting and fixing outer hole 1004 correspond to those of the connecting and fixing inner hole 606 on the bearing outer sleeve 6. By inserting a countersunk bolt into the connecting and fixing outer hole 1004 and the connecting and fixing inner hole 606, the bearing outer sleeve 6 and the outer shell 10 can be fixed together.

[0062] Reference Figure 14 , The protective boot 11 is arranged on the side of the milling cutter 1. The protective boot 11 includes a boot head 1101, a boot rod 1102 and a boot body 1103. The two ends of the boot rod 1102 are respectively connected to the boot head 1101 and the boot body 1103. The boot head 1101 is in the shape of an arc-shaped crescent block. There is a jack on its middle part that fits the tool bit 101, and the tool bit 101 can rotate around the boot head 1101; the boot body 1103 is in the shape of an arc-shaped block, and there are a clamping groove 1104 and a ball head groove 1107 on it. There is a pin hole 1105 on the wall of the clamping groove 1104. The pin hole 1105 corresponds to the circular hole at the head of the Z-shaped rod 702. By inserting a connecting pin 1106 into the pin hole 1105 and the circular hole, the protective boot 11 can rotate around the connecting pin 1106. And the rotating ball head 1001 on the outer shell 10 is inserted into the ball head groove 1107 of the boot body 1103, enabling the protective boot 11 to rotate around the ball head groove 1107 with the rotating ball head 1001, thus playing a role in limiting the protective boot 11. The wall surfaces of the boot rod 1102 and the boot body 1103 are not on the same straight line but are inclined at a certain angle. When the boot body 1103 rotates around the ball head groove 1107, the milling cutter 1 connected to the boot head 1101 can be pulled to rotate through the boot rod 1102, so as to achieve the purpose of adjusting the angle of the milling cutter 1.

[0063] Reference Figure 2 , On the outside of the tail shaft body 202 of the main shaft 2, there is a handle installation part. The handle installation part includes a connecting shaft sleeve 3, an inner shell 12 and a locking ring 13. There is a radial hole 204 on the tail shaft body 202. Reference Figure 9, the connecting bushing 3 is a cylinder with a connecting hole, and is integrally sleeved and fixed on the tail shaft body 202. The connecting hole corresponds to and is adapted to the radial hole 204. By inserting a pin 205 into the connecting hole and the radial hole 204, the connecting bushing 3 can be fixed on the main shaft 2, and then the main shaft 2 is connected to the power output shaft of the power handle through the connecting bushing 3.

[0064] Reference Figure 17 、 Figure 18 And Figure 20 , the inner shell 12 is cylindrical. The outer wall at one end is provided with butt threads 1202, and the butt threads 1202 are adapted to the internal threads 601 on the third step 605 of the bearing outer sleeve 6. The inner shell 12 is threadedly connected to the bearing outer sleeve 6. A locking ring 13 is arranged on the outer side of the inner shell 12, and the end face of the locking ring 13 is in contact with the end face of the third step 605 of the bearing outer sleeve 6. A concave ring 1201 is provided on the outer wall of the middle part of the inner shell 12. By sleeving a sealing ring 1203 on the concave ring 1201, the inner shell 12 and the locking ring 13 are firmly connected. To facilitate the insertion and removal of the power handle, a plurality of through holes 1204 are also opened on the side wall of the inner shell 12, and steel balls are arranged in the through holes 1204, and the steel balls can movably catch the power handle.

[0065] The bone milling cutter of the present invention can adjust the angle of the milling cutter 1 according to the shape of the bone tissue structure during the operation through the angle adjustment component, so that the milling cutter 1 is always perpendicular to the bone tissue. In a narrow surgical cavity or a complex bone tissue (such as a knee with many corners) environment, it is not necessary to move a large range or take out the entire milling cutter 1 for direction and angle adjustment, and precise and fine angle adjustment can be achieved, reducing the adjustment difficulty, saving the operation time, and improving the milling effect.

[0066] The above is only a preferred embodiment of the present invention. This embodiment does not represent all possible forms of the present invention. The protection scope of the present invention is not limited to such specific statements and embodiments. Various other deformations and improvements that do not depart from the essence of the present invention are made according to these technical revelations disclosed in the present invention, and these deformations and improvements are still within the protection scope of the present invention.

Claims

1. A bone milling cutter with adjustable angle, characterized in that: include: A milling cutter (1), a spindle (2), a protective shoe (11), and an angle adjustment component; The milling cutter (1) comprises a cutter head (101), a cutting edge (102) and a cutter tail (103); the cutter tail (103) is transmission-connected to the spindle (2) via a universal joint (14); and the cutter head (101) is clamped to the protective shoe (11), so that the milling cutter (1) can rotate by the rotation of the protective shoe (11); The angle adjustment assembly is arranged outside the main shaft (2), and the angle adjustment assembly comprises a follower (7), a spring (8), an adjustment cylinder (9) and a housing (10); The follower (7) is rotationally matched with the protective boot (11) and is limited by the housing (10); the follower (7) is driven to move by the adjustment cylinder (9) and is reset by the spring (8); The main shaft (2) comprises a shaft head (201), a tail shaft body (202), and a middle step (203) located between the shaft head (201) and the tail shaft body (202); The outer walls of the shaft head (201) and the tail shaft body (202) are sleeved with bearings (4); The middle step (203) is externally sleeved with a spacer sleeve (5), the spacer sleeve (5) is limited by bearings (4) at both ends, the outer side of the spacer sleeve (5) is sleeved with a bearing outer sleeve (6), and the follower (7) is slidably arranged on the outer wall of the bearing outer sleeve (6); The main shaft (2) is connected to a handle mounting portion, the handle mounting portion comprising a connecting sleeve (3), an inner shell (12) and a locking ring (13), the connecting sleeve (3) being sleeved and connected to the outer wall of the main shaft (2), the inner shell (12) being arranged on the outer side of the connecting sleeve (3) and being threadedly connected to the bearing outer sleeve (6), and the locking ring (13) being arranged on the outer side of the inner shell (12); The universal joint (14) comprises a front shaft sleeve (1401) and a rear shaft sleeve (1402); a clamping hole (1408) is provided on the side wall of the front shaft sleeve (1401); the knife tail (103) is inserted into the front shaft sleeve (1401) and fixed by inserting a clamping column (104) into the clamping hole (1408); The front shaft sleeve (1401) is also provided with an arc-shaped groove (1403) and a keyway (1405); The rear shaft sleeve (1402) is also provided with an extension section of the keyway (1405), a connecting key (1406) is arranged in the keyway (1405) and the extension section of the keyway (1405), and the connecting key (1406) is rotatably connected to the front shaft sleeve (1401) via a pin rod (1407); The shaft head (201) of the main shaft (2) is inserted into the interior of the rear shaft sleeve (1402) and extends to the arc-shaped groove (1403) in the front shaft sleeve (1401); a convex ball block (1404) is provided on the rear shaft sleeve (1402); the convex ball block (1404) is inserted into the arc-shaped groove (1403) and is rotatably arranged.

2. The angle-adjustable bone milling cutter according to claim 1, characterized in that: The bearing outer sleeve (6) comprises a first step (603), a second step (604) and a third step (605) whose heights increase in sequence, an outer wall of the second step (604) being provided with an external thread (602), and an inner wall of the third step (605) being provided with an internal thread (601); A limiting plane (607) is provided on the wall surface of the first step (603), and a connecting and fixing inner hole (606) is provided in a radial direction on the limiting plane (607).

3. The angle-adjustable bone milling cutter according to claim 2, characterized in that: The driven member (7) comprises an integrally formed slide cylinder (701) and a Z-shaped rod (702); the Z-shaped rod (702) is located on the end surface of the slide cylinder (701); and a circular hole is formed at the head of the Z-shaped rod (702).

4. The angle-adjustable bone milling cutter according to claim 3, characterized in that: The protective boot (11) comprises a boot head (1101), a boot stem (1102) and a boot body (1103), wherein two ends of the boot stem (1102) are respectively connected to the boot head (1101) and the boot body (1103); The boot head (1101) is provided with a socket, and the blade head (101) is plugged into the socket; The boot body (1103) is in an arc-shaped block shape, and is provided with a slot (1104) and a ball head slot (1107). The slot wall of the slot (1104) is provided with a pin hole (1105), and the pin hole (1105) corresponds to the circular hole. By inserting a connecting pin (1106) into the pin hole (1105) and the circular hole, the protective boot (11) is rotated around the connecting pin (1106).

5. The angle-adjustable bone milling cutter according to claim 4, characterized in that: The housing (10) is cylindrical, and a rotating ball head (1001) is provided on the end surface of one end thereof, and a position avoidance groove (1003) is provided on the side wall thereof along the axial direction, and the head of the Z-shaped rod (702) of the follower (7) is located in the position avoidance groove (1003); The rotating ball head (1001) is inserted into the ball head groove (1107) and is rotationally matched with the boot body (1103); An inner step (1002) is provided on the inner wall of one end of the outer shell (10), and a connecting and fixing outer hole (1004) is provided on the inner step (1002), wherein the connecting and fixing outer hole (1004) corresponds to the connecting and fixing inner hole (606) in position and size.

6. The angle-adjustable bone milling cutter according to claim 5, characterized in that: A plurality of through holes (1204) are also provided on the side wall of the inner shell (12), and steel balls are arranged in the through holes (1204), and the power handle is clamped by the steel balls.

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