Please select the most similar patent number from A, B, C and D. Which number is?
Disclosed are a vertical milling insert (5) and a dense gear milling cutter, wherein the vertical milling insert (5) comprises an insert body (1) and a cutter head unit, the insert body (1) is provided with a mounting hole (11) for mounting the vertical milling insert (5) on the milling cutter, the cutter head unit is mounted on the insert body (1), and the cutter head unit is of a dual cutter head structure. In the vertical milling insert (5), a folded surface structure cooperates with a positioning structure in the milling cutter for positioning, and when in use, the folded surface structure will not be worn, such that reliable positioning can be ensured when two cutters are used.
A: A disc-type underreamer, helping process different apertures, comprises a main shaft (1) connected to a motor output shaft. One end of the main shaft (1) is connected with a circular aperture regulation disc (2), and the aperture regulation disc (2) is rotatably sheathed in a cutterhead (3) arranged on the front end of the aperture regulation disc (2). A rear side of the cutterhead (3) is provided with an embedding groove (30) in nested cooperation with the aperture regulation disc (2), and a front side of the cutterhead (3) is radially provided with at least one pair of blade assemblies (5) symmetrically arranged relative to the center of the cutterhead (3). Each blade assembly (5) comprises a blade (50), a cutter holder head (51), and a cutter holder driving block (52) fixed on the cutter holder head (51). The blade (50) is perpendicularly fixed on the cutter holder head (51). Two sides of a junction of the cutter holder head (51) and the cutter holder driving block (52) form an &#39;&#39;I&#39;&#39;-shaped groove (511), the corresponding cutterhead (3) is radially provided with an inverse &#39;&#39;T&#39;&#39;-shaped groove (31), and the &#39;&#39;I&#39;&#39;-shaped groove (511) on the junction of the cutter holder head (51) and the cutter holder driving block (52) is sheathed in the inverse &#39;&#39;T&#39;&#39;-shaped groove (31) of the cutterhead (3) and capable of sliding along the radial direction. An inner side of the aperture regulation disc (2) is provided with an involutes-shaped spiral groove (20) distributed on the whole disc surface. A bottom side of the corresponding cutter holder driving block (52) is provided with a plurality of tooth blocks (520) engaged with the spiral groove (20).
B: A practical knife having a locking structure. The practical knife comprises a housing (1), a knife frame (2), a blade (3), a pushing button (4), and a knife frame locking device (5); the front end of the housing (1) is provided with a blade stretchable port (11) which can be used for stretching and retracting the blade (3), and a sliding groove which can be used for moving the pushing button (4) is provided on the side surface of the housing (1); and the blade (3) is mounted in the housing (1) by means of the knife frame (2) in a matched manner, and the blade (3) is controlled to be stretched and retracted in the blade stretchable port (11) by means of the pushing button (4); the knife frame locking device (5) achieves stretching locking the blade (3) by locking the knife frame (2). The knife frame locking device is adopted for locking the knife frame, the stretchable movement of the blade is limited, and thus the locking of the blade is achieved, and it is guaranteed that when this product is used, the blade cannot automatically stretch and retract so as to influence the cutting work.
C: A milling cutter for chamfering, comprising a body (10), at least one blade (20), and at least two guide posts(30); the body (10) comprises an installation section (11) and a cutting section (12); the blade (20) is removably installed on the cutting section (12), therefore the blade (20) can be separately replaced when worn dull; the guide posts(30) are disposed on the cutting section (12) and protrude out of the outer surface of the cutting section (12), therefore when the blade (20) contacts and cuts a hole wall, the guide posts (30) simultaneously press against the hole wall, achieving the effects of reducing relative vibration and polishing; and the cutting section (12) itself is in a simply conical shape, thus facilitating manufacturing and reducing cost.
D: Disclosed are a protection member (3), a blade assembly (10), and a mower (20). The mower (20) comprises: a machine body (206), a disk cutter (1), and the blade assembly (10), wherein the disk cutter (1) is arranged on the machine body (206); the blade assembly (10) is connected to the disk cutter (1) so as to follow the rotation of the disk cutter (1); and the blade assembly (10) comprises a blade (2) provided with a cutting part (21), and the protection member (3) arranged outside the blade (2) to prevent the cutting part (21) from being accidentally touched, the blade (2) is connected to the disk cutter (1), and at least part of a side edge of the cutting part (21) is exposed from the protection member (3) to facilitate cutting. In this way, by means of providing the protection member (3), the cutting part (21) of the blade (2) can be prevented from coming into direct contact with a person, such that the person can be prevented from being cut by the blade (2), so as to improve the use safety of the mower (20), and the blade (2) can also be protected so as to prolong the service life of the blade (2).
Answer: C