Multi-blade cutting strip and cutter for wood planing machine

A cutter includes a rotary shaft having a longitudinal axis and a plurality of circumferentially spaced-apart multi-blade cutting strips each of which includes a plurality of cutting blades spacedly provided at at least one longitudinal side edge of a cutting strip body thereof. Each cutting blade of each cutting strip has a portion (P1) staggered with respect to an adjacent cutting blade of an adjacent cutting strip along a circumferential direction around the longitudinal axis, and a remaining portion (P2) aligned with the adjacent cutting blade of the adjacent cutting strip along the circumferential direction. The portion (P1) has an offset length (D) measured along the longitudinal direction.

CROSS REFERENCE TO RELATED APPLICATION

This application claims priority of Taiwanese Application Number 103211271, filed on Jun. 25, 2014.

FIELD

The disclosure relates to a planing blade of a wood planing machine, more particularly to a multi-blade cutting strip and a cutter for the wood planing machine.

BACKGROUND

Referring toFIG. 1, a conventional cutter for a wood planing machine, as disclosed in U.S. Pat. No. 4,538,655, includes a rotary shaft11extending along a longitudinal direction and rotatable about an axis, a plurality of cutting strips12and a plurality of fasteners13. The cutting strips12are elongated, are parallel to the axis, and are circumferentially disposed on the shaft11. The fasteners13respectively fix the cutting strips12on the shaft11.

During the planing process, the whole piece of each cutting strip12is in contact with a to-be-planed surface of a workpiece. Because a contact area between each cutting strip12and the to-be-planed surface of the workpiece is large, when the shaft rotates in high speed, each cutting strip12imposes a high impact against the to-be-planed surface. Aside from producing a large sound or noise, because the resistance is large, a huge amount of energy is consumed, so that the work efficiency is reduced. Further, each cutting strip12is easily damaged.

FIG. 2illustrates another conventional cutter of a wood planing machine. The conventional cutter includes a rotary shaft21, a plurality of cutting blades22and a plurality of fasteners23. The shaft includes a plurality of circumferentially spaced-apart spiral side surfaces211extending along a longitudinal direction. The cutting blades22are disposed on the spiral side surfaces211. Each fastener23extends through a respective one of the cutting blades22and engages a corresponding spiral side surface211to thereby fix each cutting blade22on the shaft3.

The cutting blades22are small in size and are disposed in the spiral side surfaces211of the shaft21. Thus, a contact area between the cutting blades22and a to-be-planed surface of a workpiece is reduced. After each cutting blade22planes a small region of the to-be-planed surface, a next one of the cutting blades22continues the planing process. This can effectively decrease the noise and the resistance produced during planing of the to-be-planed surface of the workpiece. However, because the shaft21needs to go through a fine processing so that the side surfaces211thereof extend in a spiral manner, and because the cutting blades22are small in size so that it is difficult to manufacture and process the same, a high investment is thus required for the manufacture and process of the shaft21and the cutting blades22.

SUMMARY

Therefore, an object of the present disclosure is to provide a multi-blade cutting strip which has a reduced processing cost.

Accordingly, a multi-blade cutting strip of this disclosure comprises a cutting strip body extending along a longitudinal direction and having two opposite longitudinal side edges, a plurality of cutting blades spacedly provided at at least one of the longitudinal side edges, and a plurality of spacer sections each formed between two adjacent ones of the cutting blades. Each of the cutting blades has a blade edge extending along the longitudinal direction.

Another object of this disclosure is to provide a cutter which has a reduced cost and which can decrease noise and resistance during planing.

Accordingly, a cutter comprises a rotary shaft having a longitudinal axis, and a plurality of circumferentially spaced-apart multi-blade cutting strips disposed on an outer surface of the rotary shaft. Each of the multi-blade cutting strips includes a cutting strip body extending along a longitudinal direction parallel to the longitudinal axis and having two opposite longitudinal side edges, a plurality of cutting blades spacedly provided at at least one of the longitudinal side edges, and a plurality of spacer sections each formed between two adjacent ones of the cutting blades. Each of the cutting blades has a blade edge extending straightly along the longitudinal direction. The cutting blades of each of the multi-blade cutting strips are respectively and circumferentially staggered with respect to the cutting blades of an adjacent one of the cutting strips. Each of the cutting blades of each of the multi-blade cutting strips has a portion (P1) staggered with respect to an adjacent one of the cutting blades of an adjacent one of the multi-blade cutting strips along a circumferential direction around the longitudinal axis, and a remaining portion (P2) aligned with the adjacent one of the cutting blades of the adjacent one of the multi-blade cutting strips along the circumferential direction. The portion (P1) has an offset length (D) measured along the longitudinal direction.

DETAILED DESCRIPTION

Before the present disclosure is described in greater detail with reference to the accompanying embodiments, it should be noted herein that like elements are denoted by the same reference numerals throughout the disclosure.

Referring toFIGS. 3, 4 and 4A, the first embodiment of a cutter according to the present disclosure is shown to comprise a rotary shaft3, a plurality of multi-blade cutting strips4, and a plurality of fasteners5.

The rotary shaft3has a longitudinal axis (X) and is rotatable about its longitudinal axis (X). The rotary shaft3includes a plurality of circumferentially spaced-apart rows of fastening holes31formed in an outer surface thereof. The fastening holes31in each row are arranged in a spaced apart manner along the length of the shaft3. Each of the fastening holes31has a screw hole portion311, and a positioning hole portion312which has a diameter larger than that of the screw hole portion311, which communicates with the screw hole portion311and which is located on an outer side of the screw hole portion311.

The multi-blade cutting strips4are respectively disposed on the rows of the fastening holes31. In this embodiment, the number of the cutting strip4is six. Each multi-blade cutting strip4includes a cutting strip body41extending along a longitudinal direction (A) parallel to the longitudinal axis (X) and having two opposite longitudinal side edges411, a plurality of cutting blades42spacedly provided at both of the longitudinal side edges411, a plurality of spacer sections43each formed between two adjacent ones of the cutting blades42, and a plurality of fixing holes44extending through the cutting strip body41and spaced apart from each other along the length of the cutting strip body41.

In this embodiment, each longitudinal side edge411is provided with five cutting blades42. Each cutting blade42has a cutting blade body421extending outward from a corresponding longitudinal side edge411in a direction perpendicular to the longitudinal direction (A), and a blade edge422formed on the cutting blade body421and extending straightly along the longitudinal direction (A). The five cutting blades42cooperate with the corresponding longitudinal side edge411to define four spacer sections43.

Each of the cutting blades42of each cutting strip4has a portion (P1) staggered with respect to an adjacent one of the cutting blades42of an adjacent one of the cutting strips4along a circumferential direction around the longitudinal axis (X), and a remaining portion (P2) aligned with the adjacent one of the cutting blades42of the adjacent one of the cutting strips4along the circumferential direction, as shown inFIG. 4A. The portion (P1) has an offset length (D) measured along the longitudinal direction (A). The blade edge422of each cutting blade42has an axial length (L1) larger than the offset length (D). During rotation of the shaft3about the axis (X), each cutting blade42of a leading one of the cutting strips4planes a region of a surface, and an adjacent one of the cutting blades42of an adjacent trailing cutting strip4succeeds planing another region overlapping with this region.

In this embodiment, the cutting blades42of the multi-blade cutting strips4are arranged in a helical array about the axis (X). The blade edge422of each cutting blade42of each cutting strip4is staggered with respect to the blade edge422of an adjacent one of the cutting blades42of a leading one of the cutting strips4by the offset length (D) when the shaft3rotates. As best shown inFIG. 4A, in combination withFIG. 4, each of the spacer sections43formed between two adjacent ones of the cutting blades42of one of the cutting strips4has an axial length (L2) smaller than the sum of the offset lengths (D) of the portions (P1) of the cutting blades42of the remaining cutting strips4that are staggered with the two adjacent ones of the cutting blades42in the circumferential direction and that are at least partially aligned with the axial length (L2) in the circumferential direction. That is, five offset lengths (D) in one revolution of the shaft3about the axis (X) are larger than the axial length (L2) of one spacer section43. When the shaft3rotates one revolution about the axis (X), the amount of feed of the blade edges422of the cutting blades42of the cutting strips4is enough to plane areas not covered by the spacer sections43.

Each of the fasteners5has a threaded shank section51for threaded engagement with the screw hole portion311of a respective fastening hole31, a positioning shank section52for embedding in the positioning hole portion312of the respective fastening hole31and having a diameter larger than that of the threaded shank section51, and a head53fixed to the positioning shank section52opposite to the threaded shank section51and exposed from the positioning hole portion312of the respective fastening hole31.

During assembly, each fastener5extends through a respective fixing hole44, and engages the corresponding fastening hole31. Specifically, the threaded shank section51of each fastener5is detachably engaged to the respective fastening hole31, and the positioning shank section52thereof is embedded in the respective fixing hole44and the positioning hole portion312of the corresponding fastening hole31. The head53presses the cutting strip body41of the corresponding cutting strip4against the shaft3. The positioning hole portion312and the positioning shank section52has a clearance smaller than that between the screw hole portion311and the threaded shank section51. Through this, the cutting strip bodies41of the cutting strips4are tightly positioned on the shaft3. Further, because the positioning shank section52of each fastener5is embedded in the respective fixing hole44and the positioning hole portion312of the corresponding fastening hole31, a slight displacement of each cutting strip4relative to the shaft3along the longitudinal direction (A) may be prevented.

From the aforesaid description, the advantages of the first embodiment may be summarized as follows:

1. Through the relative disposition of the cutting blades42of the cutting strips4, when the shaft3rotates one revolution about the axis (X), the regions planed by the cutting blades42of the cutting strips4overlap each other so that a whole region of the to-be-planed surface can be planed by the cutting strips4without interruption.

2. Through the short configurations of the cutting blades42of the cutting strips4and through the helical arrangement of the blade edges422, when the shaft3rotates to plane the to-be-planed surface (not shown), a contact surface between the blade edges422and the to-be-planed surface can be reduced, thereby reducing the resistance and the noise produced during planing.

3. The fixing of the single cutting strip4on the shaft3of this disclosure uses a plurality of the fasteners5, so that the fixing of the cutting strip is stable. Hence, the cutting strip4of this disclosure will not easily rotate or displace after prolonged use.

4. There is no need to preform the shaft3into a helical form using a fine process, it is only necessary to dispose the cutting strips4on the shaft3as described above to produce an effect similar to that of a helically shaped shaft. Thus, the cutter of this disclosure has a lower cost as compared to that of the conventional cutter.

It is worth mentioning that the cutting strips4may be independently manufactured and sold. When the cutting strips4are damaged, they can be easily replaced.

Referring toFIGS. 5 and 6, a cutter according to the second embodiment of the present disclosure is shown to be similar to the first embodiment. However, in this embodiment, the multi-bladed cutting strips4are divided into a first cutting strip group48and a second cutting strip group49disposed on two opposite sides of the rotary shaft3. The first cutting strip group48includes three multi-blade cutting strips481,482,483. The second cutting strip group49includes three multi-blade cutting strips491,492,493. Each longitudinal side edge411of each multi-blade cutting strip481,482,483,491,492,493is provided with nine cutting blades42. The cutting blades42of one of the cutting strips481,482,483are aligned with the cutting blades42of the other one of the cutting strips491,492,493, respectively, along the circumferential direction. The blade edges422of the cutting blades42of each cutting strip481,482,483,491,492,493in each of the first or second cutting strip group48,49are respectively staggered with respect to the blade edges422of the cutting blades42of an adjacent leading one of the cutting strips481,482,483,491,492,493in the corresponding first or second cutting strip group48,49by the offset length (D) (seeFIG. 4) when the rotary shaft3rotates.

In each of the first and second cutting strip groups48,49, each of the spacer sections43formed between two adjacent ones of the cutting blades42of one of the cutting strips481,482,483,491,492,493has the axial length (L2) not larger than the sum of the offset lengths (D) of the portions (P1) (seeFIG. 4A) of the cutting blades42of the remaining cutting strips481,482,483,491,492,493that are staggered with the two adjacent ones of the cutting blades42in the circumferential direction and that are at least partially aligned with the axial length (L2) in the circumferential direction.

In this embodiment, the cutting blades42of the cutting strips481,482,483,491,492,493of each of the first and second cutting strip groups48,49forma semi-helical configuration. Because the cutting blades42of the cutting strips481,482,483correspond in position to the cutting blades42of the cutting strips491,492,493, respectively, when the shaft3rotates one revolution about the axis (X), the to-be-planed surface will be planed twice at the same region by the blade edges422of the cutting blades42of the cutting strips481,482,483,491,492,493of the first and second cutting strip groups48,49. As such, the object and the advantages described in the first embodiment can be similarly achieved using the second embodiment. Further, because the effect of planing twice the to-be-planed surface during one revolution rotation of the shaft3, the flatness of the planed surface can be enhanced, as well as the working efficiency of planing the to-be-planed surface.

Referring toFIG. 7, a cutter according to the third embodiment of the present disclosure is shown to be similar to the first embodiment. However, in this embodiment, the cutter further comprises a plurality of positioning members6, each fastener5only includes a head53and a threaded shank section51, and the rotary shaft3further includes a plurality of positioning holes32for receiving the positioning members6, respectively. Each positioning hole32is disposed between two adjacent ones of the fastening holes31. The fixing holes44in the cutting strip body41of each multi-blade cutting strip4are divided into a plurality of first fixing holes441for extension of the threaded shank sections51of the fasteners5respectively therethrough, and a plurality of second fixing holes442corresponding in position to the positioning holes32, respectively. Each second fixing hole442is disposed between each two adjacent ones of the first fixing holes441. The threaded shank section51of each fastener5extends through the respective first fixing hole441and engages the respective fastening hole31during assembly.

Each positioning member6includes an embedded portion62embedded in the respective positioning hole32, and a protruding portion61protruding from the embedded portion62and extending through the respective second fixing hole442. The embedded portion62has a diameter larger than that of the respective second fixing hole442. The protruding portion61of each positioning member6and a periphery of the respective second fixing hole442has a clearance smaller than that between each fastener5and a periphery of the respective first fixing hole441. As such, the object and the advantages described in the first embodiment can be similarly achieved using the third embodiment.

Referring toFIG. 8, a cutter according to the fourth embodiment of the present disclosure is shown to be similar to the first embodiment. However, in this embodiment, the rotary shaft3further includes a plurality of circumferentially spaced-apart abutment portions33disposed on and projecting outward from the outer surface of the shaft3. Each of the abutment portions33extends in the longitudinal direction (A). Only one longitudinal side edge411of the cutting strip body41of each multi-blade cutting strip4is provided with the cutting blades42. Each abutment portion33has an abutment surface331abutting against the cutting strip body41of the respective cutting strip4. It will be appreciated that the abutment surface331of each abutment portion33abuts against the cutting strip body41of the respective cutting strip4at a side opposite to the cutting blade42.

The object and the advantages described in the first embodiment can be similarly achieved using the fourth embodiment. With the abutment portions33abutting against the cutting strip body41of the respective cutting strips4, the stability of the cutting strips4can be enhanced.

Referring toFIG. 9, a cutter according to the fifth embodiment of the present disclosure is shown to be similar to the first embodiment. However, in this embodiment, the rotary shaft3further includes a plurality of circumferentially spaced-apart abutment portions33disposed on and projecting outward from the outer surface of the shaft3. Each of the abutment portions33extends in the longitudinal direction (A), and abuts against the cutting blade bodies421of the cutting blades42located at the same longitudinal side edge411of the respective cutting strip4along a tangential direction.

The object and the advantages described in the first embodiment can be similarly achieved using the fifth embodiment. With the abutment portions33abutting against the cutting blade bodies421of the cutting blades42of the respective cutting strips4, the stability of the cutting strips4can be enhanced.