TWI775172B - bone screw - Google Patents

Abstract

A bone screw includes a screw shaft and a screw head. The shank includes a tip section and a first threaded section formed at one end of the tip section, the tip section has one end, a plurality of cutting edges extending from the end and equiangularly spaced apart, and a plurality of The flanks are respectively formed on the rear sides of these cutting edges, and the end is an arc end face, which defines a back bevel between a cutting plane at any point on each cutting edge and the corresponding flank. The The shank is formed with a plurality of chip flutes extending from the end to the first thread segment, and each of the chip flutes is helical. A nail head is formed at an end of the first thread segment opposite to the tip segment, and the nail head includes a second thread segment. Thereby, the tip section can play the role of drilling. Because the end portion is a circular arc end face, other tissues can be prevented from being stabbed.

Description

bone screw

The present invention relates to a surgical instrument, in particular to a self-drilling and self-tapping bone screw for implanting in bone.

Conventionally, when a bone plate is to be fixed to a broken bone through a plurality of bone screws, the screw-lock operation of the bone screws needs to be performed in sequence. When screwing each of the bone screws, a guide sleeve is firstly locked to the bone plate, and then a drill bit is inserted into the guide sleeve and guided to drill holes on the bone. Then measure whether the depth of the hole drilled in the bone meets the requirements. Finally, a self-tapping bone screw is passed through the bone plate and locked into the bone at the position corresponding to the drilled hole in the bone, ie, the screw locking operation of a single bone screw is completed.

Since the screw-locking operation of each bone screw needs to be completed through the above-mentioned multiple operation steps, and each two adjacent bone screws can only be performed within an angle range with a small difference, it takes a long time for the operation. Time.

In addition, at present, self-drilling and self-tapping bone screws are used to replace the aforementioned self-tapping bone screws, thereby omitting the aforementioned numerous operation steps. However, this self-drilling and self-tapping bone screw has a sharp tip, so the tip can easily cause damage to other tissues after passing through the bone.

Accordingly, one object of the present invention is to provide a bone screw that overcomes at least one of the disadvantages of the prior art.

Therefore, in some embodiments, the bone screw of the present invention includes a screw shaft and a screw head.

The shank includes a tip section and a first threaded section formed at one end of the tip section, the tip section has one end, a plurality of cutting edges extending from the end and equiangularly spaced apart, and a plurality of The flanks are respectively formed on the rear sides of these cutting edges, and the end is an arc end face, which defines a back bevel between a cutting plane at any point on each cutting edge and the corresponding flank. The The shank is formed with a plurality of chip flutes extending from the end to the first thread segment, and each of the chip flutes is helical. A nail head is formed at an end of the first thread segment opposite to the tip segment, and the nail head includes a second thread segment.

In some embodiments, each of the flank surfaces is a circular arc surface connected to the end portion.

In some embodiments, the number of the cutting edges is three, and every two adjacent cutting edges are separated by an angle, and the angle is 120 degrees.

In some embodiments, the bone screw has a total length jointly defined by the shank and the screw head, the number of the chip flutes is three, and each of the chip flutes extends from the end to the A length of the first thread segment is between one quarter of the total length and one half of the total length.

The present invention has at least the following attacking effect: the cutting edge and the rear bevel angle of the tip section enable the tip section to play the role of drilling smoothly into the bone. Due to the design of each of the chip flutes extending from the end to the first thread segment, the bone chips generated by the tip segment during the drilling process and the first thread segment during the tapping process can be discharged into the first thread segment. Equal flute and stored in it. With the design of the end portion being a circular arc end surface and each of the flank surfaces being circular arc surfaces, it is possible to avoid stabbing other tissues located on the side surface of the bone.

Before the present invention is described in detail, it should be noted that in the following description, similar elements are designated by the same reference numerals.

Referring to FIG. 1 , an embodiment of a bone screw 100 of the present invention is a self-drilling and self-tapping bone screw and includes a screw shaft 1 and a screw head 2 .

Referring to FIGS. 1 , 2 and 3 , the nail shaft 1 includes a tip section 11 and a first thread section 12 formed at one end of the tip section 11 . The tip section 11 has one end 111 , a plurality of cutting edges 112 , and a plurality of flanks 113 . The end portion 111 in this embodiment is a circular arc end surface. The cutting edges 112 extend from the end portion 111 and are equiangularly spaced. In this embodiment, the number of the cutting edges 112 and the number of the flanks 113 are three respectively, and there is an angle A between every two adjacent cutting edges 112, and the angle A is 120 Spend. The flank surfaces 113 are respectively formed on the rear side of the cutting edges 112 , and each flank surface 113 is an arc surface connected with the end portion 111 . A relief angle θ is included between a cutting plane P defining any point on each cutting edge 112 and the corresponding flank face 113 . The relief angle θ in this embodiment is, for example, between 0 degrees and 5 degrees. .

Referring to FIGS. 1 , 2 and 4 , the shank 1 is formed with a plurality of chip flutes 13 extending from the end portion 111 to the first thread segment 12 , and each of the chip flutes 13 is helical. The number of the chip flutes 13 in this embodiment is three as an example. The nail head 2 is formed at one end of the first thread segment 12 opposite to the tip segment 11 , and the nail head 2 includes a second thread segment 21 . The head 2 is formed with a blind hole 22 for inserting a screwdriver. The bone screw 100 has a total length L jointly defined by the shank 1 and the screw head 2 , and the length D of each chip flute 13 extending from the end 111 to the first threaded section 12 is between Between one quarter of the total length L and one half of the total length L.

Referring to FIG. 1 , FIG. 2 and FIG. 5 , when a bone plate 3 is to be locked to a bone 4 through the bone screw 100 , the tip section 11 of the screw rod 1 is passed through a screw hole of the bone plate 3 31 and drill into one side 41 of the bone 4 . Through the design of the cutting edges 112 and the rear bevel angle θ (as shown in FIG. 3 ), the tip section 11 can greatly reduce the resistance when the tip section 11 is screwed into the bone 4 , so that the tip section 11 can be screwed into the bone 4 . It can play the role of drilling holes into the bone 4 smoothly. Subsequently, the first threaded segment 12 is threaded into the bone 4 and locked into the bone 4 . In this embodiment, the number of the cutting edges 112 is set to three, which can improve the cutting effect of cutting the bone 4 . Of course, in other implementations of this embodiment, the number of the cutting edges 112 may also be two or more than three, which is not limited to the number disclosed in this embodiment.

Due to the design of each of the chip flutes 13 extending from the end 111 to the first thread segment 12 , the tip segment 11 during the drilling process and the first thread segment 12 during the tapping process produce bone. Chips can be discharged into the chip flutes 13 and stored therein. Furthermore, a length D extending from the end 111 to the first thread segment 12 by each of the chip flutes 13 is between a quarter of the total length L and a half of the total length L. The design method between the two can ensure that after the first thread segment 12 is completely penetrated into the bone 4, the bone chips can be completely stored and accommodated in the chip grooves 13, and the waste of bone chips can be avoided. And can prevent any discharge of bone chips and cause environmental pollution. In the present embodiment, the number of the chip grooves 13 is set to three, which can increase the capacity of accommodating bone chips. Of course, in other implementations of this embodiment, the number of the chip flutes 13 may also be two or more than three, which is not limited to the number disclosed in this embodiment.

Finally, when the second thread segment 21 of the screw head 2 is screwed into the screw hole 31 of the bone plate 3 , the bone screw 100 locks the bone plate 3 to the side surface 41 of the bone 4 . At this time, the end 111 of the tip section 11 or a part of the end 111 and each of the relief surfaces 113 will protrude out of the other side surface 42 of the bone 4 by a small distance. FIG. 5 shows the end 111 Taking a part of each flank surface 113 protruding out of the side surface 42 of the bone 4 for example, by the design of the end portion 111 as a circular arc end surface and each of the flank surfaces 113 as a circular arc surface, the end portion 111 can be avoided. The portion 111 or each of the flank surfaces 113 punctures other tissues located at the side surface 42 of the bone 4 .

To sum up, in the bone screw 100 of the present embodiment, the tip section 11 can smoothly drill into the bone 4 by the cutting edges 112 and the rear bevel angle θ. drilling effect. Due to the design of each of the chip flutes 13 extending from the end 111 to the first thread segment 12 , the tip segment 11 during the drilling process and the first thread segment 12 during the tapping process produce bone. Chips can be discharged into the chip flutes 13 and stored therein. Because the end portion 111 is a circular arc end surface and each of the flank surfaces 113 is a circular arc surface, other tissues located on the side surface 42 of the bone 4 can be prevented from being stabbed, so the object of the present invention can be achieved.

However, the above are only examples of the present invention, and should not limit the scope of the present invention. Any simple equivalent changes and modifications made according to the scope of the application for patent of the present invention and the content of the patent specification are still within the scope of the present invention. within the scope of the invention patent.

100: Bone Screw 1: Nail bar 11: Tip segment 111: End 112: Cutting edge 113: Flank 12: The first thread segment 13: Chip flutes 2: Nail head 21: Second thread segment 22: Blind hole 3: Bone Plate 31: screw holes 4: Bones 41: Side 42: Side A: Angle D: length L: total length P: cutting plane θ: Back bevel angle

Other features and effects of the present invention will be clearly presented in the embodiments with reference to the drawings, wherein: 1 is a front view of an embodiment of a bone screw of the present invention, illustrating the relationship between a shank and a head; Figure 2 is a side view of the embodiment illustrating the relationship between one end, the plurality of cutting edges, the plurality of flanks, and the plurality of flutes; Figure 3 is a fragmentary cross-sectional view of a tip section of this embodiment; Figure 4 is a cross-sectional view taken along line IV-IV of Figure 1; and FIG. 5 is a schematic diagram of locking a bone plate to a bone in this embodiment.

100: Bone Screw

1: Nail bar

11: Tip segment

111: End

112: Cutting edge

113: Flank

12: The first thread segment

13: Chip flutes

2: Nail head

21: Second thread segment

D: length

L: total length

Claims (5)

A bone screw comprising: a shank including a tip section and a first threaded section formed at one end of the tip section, the tip section having one end, a plurality of cutting edges extending from the end and equiangularly spaced apart, and A plurality of flank faces are formed on the rear side of the cutting edges, and the end is an arc end face, defining a cutting plane at any point on each cutting edge and the corresponding flank between a back bevel angle , the shank is formed with a plurality of chip flutes extending from the end to the first threaded section, and each of the chip flutes is helical; and A nail head is formed at one end of the first thread segment opposite to the tip segment, the nail head includes a second thread segment. The bone screw according to claim 1, wherein each of the flank surfaces is an arc surface connected to the end portion. The bone screw according to claim 1, wherein the number of the cutting edges is three, and there is an angle between every two adjacent cutting edges, and the angle is 120 degrees. The bone screw according to claim 2, wherein the number of the cutting edges is three, and there is an angle between every two adjacent cutting edges, and the angle is 120 degrees. The bone screw of any one of claims 1 to 4, wherein the bone screw has a total length jointly defined by the shank and the head, and the number of the chip flutes is three, each A length of the flute extending from the end to the first thread segment is between a quarter of the overall length and a half of the overall length.

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