JPS5877493A - Cutter with cutting wheel, edge thereof is obtuse - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a sheet material cutting device, and more particularly to a rotary cutting wheel for cutting sheet material while the cutting wheel is guided over a small number of stacked sheet materials. The present invention relates to a cutting device that uses a cutting device.

By pressing a rotary cutting hole or cutting blade against a supporting surface and rolling it along the supporting surface,
Cutting wheels or plates of this type are known in the art for cutting sheet material spread in a single layer or in a small number of laminates on a flat, rigid support surface.

The cutting operation of the sheet material is accomplished by a slicing and crus'hing action between the circumference of the cutting wheel and the support surface. This type of rotary wheel and rigid support surface combination is used in the cutting device described in US Pat. No. 3,776,072.

For conventional cutting wheel geometries used with rigid support surfaces, the cutting wheel is as sharp as possible along its circumferential cutting edge to completely cut the sheet material. A well-sharpened cutting wheel should, in theory, maximize the slicing action of the wheel as it rolls along the cutting path on the sheet material, and the distance between the wheel and the supporting surface to cut the sheet material. Minimize the pressure value required to be applied. However, the use of sharp rotating wheels with hard support surfaces also has various disadvantages.

The first disadvantage relates to the cutting wheel itself, which is very thin in the vicinity of its cutting edge and is therefore susceptible to damage from the pressure exerted between the wheel and the supporting surface. Furthermore, when the cutting edge is pressed against the support surface, internal stresses in the wheel promote chipping or cracking of the cutting edge.

A second drawback relates to the support surface, which can be scored or kerbed by the sharp edges of the wheel.

Damage caused by such defects shortens the useful life of the cutting wheel and the supporting surface, and also adversely affects the cutting operation. If the wheel has a kerf or a kerf on the support surface, as the wheel rolls along the cutting path, the sheet material in the cutting path will be exposed to the kerf on the wheel or the kerf on the support surface. They may become indented or forced inward, thereby preventing complete cutting of the sheet material along the cutting path.

SUMMARY OF THE INVENTION It is therefore an object of the invention to provide a cutting device equipped with a rotary cutting wheel, which makes it possible to eliminate the above-mentioned drawbacks.

The invention relates to a device for cutting sheet material spread in a single layer or in a small number of stacks on a support surface, the device comprising a support surface for the sheet material and a rotary cutting device in the form of a circular disk. It consists of a wheel, a transport device for moving the cutting wheel along the cutting path, and a device for pressing the cutting edge of the cutting wheel against the support surface as the cutting wheel moves along the cutting path. The novel form of the cutting wheel of this invention is characterized by a blunt circumferential cutting edge that rolls over the support surface in cutting engagement with the sheet material spread over the support surface.

This cutting operation is therefore accomplished by a crushing action that breaks up the sheet material between the blunt cutting edge of the wheel and the support surface as the cutting wheel moves relative to the support surface.

The potential for damage to the cutting wheel or supporting surface due to the use of a cutting wheel can be substantially reduced by using a blunt cutting wheel for two reasons. The first reason is that a wheel with a blunt cutting edge has stronger strength near the circumferential cutting edge than a wheel of the same diameter with a sharp cutting edge. and secondly, wheels with blunt cutting edges are less prone to damage the supporting surface than wheels with sharp cutting edges.Thus, based on the present invention, The present invention extends the useful life of the wheel and support surface by preventing damage to the wheel and support surface in the form of wheel nicks or kerfs in the support surface, thereby preventing cutting. Complete cutting of the sheet material along the path can be achieved.

Next, the embodiment illustrated in the drawings will be described in detail.

FIG. 1 illustrates an automatic cutting system for cutting sheet material embodying the invention. The system, shown generally at 10, includes a cutting table 12 and a cutting tool 14.
, an X carriage 16 that moves in the X coordinate axis direction on the cutting table 12, and an The apparatus comprises a control computer 20 coupled to the carriage and the tool to control the movement of the tool during the cutting operation. The control computer 20 receives and receives program information from the memory tape 22 and develops cutting control signals corresponding to the program information.

This control signal is transmitted via command cable 24 to carriages 16 and 18 to move tool 14 over table 12 in cutting engagement with sheet material S. (The computer controlling the memory tape 2
Based on the program information defined by 2, the tool is guided along a cutting path in the sheet material around the turn piece shown in dashed lines.

The cutting table 12 includes a frame 30 resting on a plurality of legs 32 and a working surface formed by a bed 34 , which forms a working surface on which the sheet material S can be spread. No. 35 has sufficient hardness so that it will not be damaged by the cutting tool when it is pressed against the work surface during cutting.

The X-carriage 16 is connected to the cutting table 1 by a pair of racks 48 and 50 which extend longitudinally along the edge of the cutting table 12 in the direction of the
It is supported above 2. The drive motor and pinion (not shown) in the rack 48 and 5
According to the movement command transmitted from the computer 20, the carriage 16 and the tool 14 are engaged with the teeth of the tool 14.
is moved back and forth on the table in the direction of the X coordinate axis.

The X carriage 18 is attached to the X carriage 16 by a guide rail 58 extending in the direction of the X coordinate axis between both ends of the X carriage 16 and a lead screw 60. Lead screw 6 rotated by another drive motor (not shown) controlled by computer 20
0 is the X carriage 18 to position the X carriage 18 and the tool 14 on the table in the direction of the X coordinate axis.
is threadedly engaged. Machining of the table 12 in cutting engagement with the sheet material so as to cut along the circumference of the pattern piece by means of compound movements of the tool 14, x carry:) 16 and Y carry:) 18. It can be moved in any desired direction on the surface.

As clearly shown in FIGS. 2 and 6, the cutting tool 14 is attached to the X-carriage 18 by a support 62 extending in cantilevered form from an adjustable mounting 64 on the projecting end of the X-carriage 18. A suspended, adjustable mount 64 is moved up and down relative to the work surface of table 12 by a computer controlled motor (not shown). The cutting tool 14 is therefore brought into cutting engagement with the sheet material S at the beginning of the cutting operation and lifted out of contact with the sheet material S at the end of the cutting operation. The cutting tool 14 comprises a cutting wheel 7o, which crushes when the cutting tool is pressed downwardly into engagement with the sheet material S due to the pressure from the support 62. It has a circumferential cutting edge that cuts the sheet material S by its action. The cutting wheel 7o is free to rotate about an axis parallel to the work surface as the wheel is rolled along the work surface of the table 12 by the carriages 16 and 18 in cutting engagement with the sheet material S. It is supported by a tool holder 72 so that it can be moved freely.

The wheel 70 and the holder 72 are transported together with the support base 62 by a journal-supported support shaft 80K.
This support shaft 80 is perpendicular to the machining surface of the table 12.
The tool is rotated around the axis 82. The rotary drive motor 84 is connected to the shaft 80 by a toothed bolt 86 which is passed between a large diameter shaft pulley 89 fixed to the upper end of the support shaft 8o and a motor pulley 88. Rotation commands are extracted from the memory tape 22 by the computer 20 and applied to the drive motor 84K to control the rotational angular attitude of the cutting wheel. Therefore, the cutting wheel can be moved tangentially along the edge of the chisel turf piece at each position.

A load control mechanism is interposed between the cutting tool 14 and the tool carriage 18 supporting the cutting tool 14, providing a pressing force to the tool. The cutting tool is pressed along the θ axis 82 by force into cutting engagement with the sheet material S on the processing surface. The load control mechanism, illustrated generally at 100, includes a pneumatic or hydraulic load cylinder assembly 102 and a support platform 62K.
It is fixedly mounted on a small connected bridge 104. The load cylinder assembly 102 has a piston rod 1o6 on which the chuck and tool 14 rotate with an axis 80 and a support base 6.
A collar 112 extends coaxially through a central hole in the shaft 80 so as to be slidable axially along the shaft 80 with respect to the collar 112 and is pivotable to a spline on the distal end of the shaft 80. Fixed tool holder 72 K thrust”?7
This thrust earring 110 is connected via a piston rod r1 when pressed.
06 to the cutting wheel 70 while
The holder 72 allows the cutting wheel 7o to rotate about the θ axis 82.

The force with which the cutting wheel is forced into the sheet material S as the applied load is determined by the pressure applied to the load control cylinder assembly 102 via pressure lines 114 and 116. The load thus applied must be of sufficient magnitude to cut the sheet material by a crushing action as the wheel rolls along the surface of the sheet material. After the cutting operation, the pressure in lines 114 and 116 is reduced to zero, and tool 14 is attached to support base 62 and adjustable when a lifting ring 120 fixed to the lower end of shaft 80 contacts collar 112. 64 from the cutting table.

The diameter of the cutting wheel 70 is within a range limited by the practical requirements associated with this type of cutting system. The first requirement is that the diameter of the wheel is such that the height of the laminate is aligned with the axis of rotation of the wheel or horizontally when the circumferential surface of the wheel is pressed against the support surface in cutting engagement with the sheet material. It must be of such a size that it does not rise above the mid-plane. If the height of the stack is less than the horizontal intermediate plane of the wheel, the sheet material in the rolling cutting path of the cutting wheel will be pressed against the support surface by the cutting edge of the wheel, and no part of the stack will be in contact with the tool holder 72. There is no contact or interference.

Furthermore, for a minimum diameter of the wheel, it is also a requirement that the wheel must rotate along the cutting path as a result of a frictional driving force between the edge of the wheel and the sheet material and/or supporting surface. In order for the wheel to rotate, the frictional driving force must be large enough to overcome the resistive frictional force acting between the wheel 70 and the wheel holder 72 near the wheel axis. Generally speaking, the larger the diameter of the wheel, the easier it is for the frictional driving force to overcome the frictional force that resists rotation.

The maximum diameter of the wheel is limited to prevent excessive displacement of the sheet material when the wheel is turned to follow a bend or corner in the cutting path. The larger the wheel, the greater the possibility that the sheet material adjacent to the cutting path will move and wrinkle during deflection about the θ axis of the wheel.

The diameter of the cutting wheel is preferably less than 3.0 inches (76.2 m) and greater than 0.25 inches (6,351111) due to the aforementioned practical requirements that limit its size.

The cutting wheel 70 is constituted by a thin disc having a substantially uniform thickness between the axial sides of the wheel and a blunt cutting edge 71, as shown in detail in FIGS. 4 and 5. ing. This blunt cutting edge 71 has, for example, a radius of curvature R that is approximately half or more of the thickness of the wheel. A typical radius of curvature is 0.001 to 0.0104. (0,025~0
．． 254m).

A blunt circumferential cutting edge 71 is preferred over a normal sharp cutting edge for practical reasons. When the load control mechanism 100 applies a force to the cutting wheel 70K, a considerably large stress is created between the cutting edge and the flat support surface 35 of the rad 34. The high levels of stress associated with sharp cutting edges have several disadvantageous effects on cutting operations.

One effect of high levels of stress is to degrade the cutting edge of the wheel. When the wheel is formed of a brittle hard material, fractures occur along the cutting wheel due to fracturing, where pieces or fragments break off and separate from other parts of the cutting wheel.

Small nicks or chips on a continuous cutting edge can cause discontinuous cuts along the cutting path.

Such cutting operations result in uncut fibers and other material between the pattern pieces and the surrounding material. Therefore, when removing the pattern pieces, the uncut material is pulled and the material is damaged due to tearing or tearing.

Furthermore, the high level of stress associated with a sharp circumferential cutting edge adversely affects the support surface 35K of the cutting table.

Generally speaking, the support surface is formed of a material with a hardness less than that of the cutting wheel. Preferably, the support surface is no harder than 40 Rockwell C hardness.

Ideally the support surface should be flat, but concentrated stress along the cutting path causes kerfs in the support surface. Thus, after repeated use, the support surface 35 will include a series of kerfs defining pattern pieces cut in previous cutting operations. Such kerfs or cuts form discontinuities in the cut surface, and have the same effect as discontinuities in a circumferential cutting edge. The sheet material is recessed into the kerf, partially blocking the cut at the intersection of the kerf and the cutting path.

By using a cutting wheel with a blunt circumferential cutting edge 71 according to the invention, problems such as chipping and kerfs can be virtually eliminated.

By using a blunt cutting edge, the wheel has substantially greater strength in the cutting edge area, and the stresses generated in both the wheel and the supporting surface are of a much lower level. Due to the strong wheel and reduced stress, the possibility of kerfing is effectively eliminated.

Similarly, a large contact area between the cutting edge and the support surface creates a small stress on the rad 34 and the support surface 3
5. Permanent deformation and kerfs are not completely eliminated (but are reduced to a level that does not affect the cutting operation).

It is known from experience that the cutting action of a blunt cutting edge makes it possible to cut flexible sheet materials, such as woven and non-woven fabrics, despite the fact that the cutting edge is arcuate. This cutting operation has changed from one in which the material is cut by both a slicing action and a crushing action to a forming one in which the cutting is performed primarily by a crushing action. In the experiment,
Although small traces of crushed sheet material were seen along the cutting line, it was observed that cutting of the material was accomplished nevertheless. For some materials, pressing requires an increase in the magnitude of the force, when an increase in the area of contact between the blunt cutting edge and the supporting surface will result in a higher level of stress. This will not result in damage to the kerf or the like.

6 and 7 further illustrate another embodiment of the blunt cutting wheel of the present invention. Both wheels 9° and 92 have cutting edges 91 and 93, respectively, defined by narrow, flat cylindrical surfaces extending around the circumference of the wheels. The diameter of the wheel 9Q92 is between 6.0 inches (76,21111) and 0.25 inches (6,3
51111) or more are preferred. This flat cylindrical cutting edge acts substantially like a blunt cutting edge 71 having an arcuate curvature between the axial end faces of the cutting wheel. A flat cutting edge is an arcuate cutting edge whose radius of curvature corresponds to infinity. To maintain efficient cutting with a flat edge, the width of the edge should be between 0.002 and 0.005 in+
It is preferable to set it in the range of (0,050-0,127+a+).

The wheel 90 of FIG. 6 is of a unitary construction, unlike the wheel 92 of FIG. 7 in this respect.

The wheel 92 is an essentially thin disc with a width no greater than a flat cylindrical cutting edge 93, and reinforcing plates 94,96 are mounted coaxially on each side of the disc to provide bearing strength near the axis 98. It's increasing.

Although the invention has been described in detail with reference to several embodiments, it will be understood that various modifications and changes may be made without departing from the spirit of the invention. For example, a cutting wheel with a blunt circumferential cutting edge may have a uniform width or a tapered, stepped, hyperbolic width between its center and the circumferential cutting edge. The bearing insert can be centrally located in the wheel, or the wheel can be fixedly mounted on a journal journalled axle within the tool holder. The bearing structure that allows the wheel to rotate freely within the holder should have little or preferably no freedom of movement, as alignment of the wheel within the device is critical for accurate following of the cutting path. is important.

The precise profile of the blunt cutting edge can range from an arcuate cutting edge with increasing radius of curvature between the axial sides of the cutting wheel and the apex of the cutting edge to a flat cutting edge. Accordingly, this invention is disclosed by way of illustration rather than limitation.

[Brief explanation of the drawing]

1 is a perspective view of a cutting device embodying the invention, and FIG. 2 is a side view of the cutting tool and cutting table of FIG. 1, illustrating a load control mechanism coupled to the tool. , FIG. 6 is a front view of the apparatus shown in FIG. 2, FIG. 4 is a slightly enlarged front view of the cutting wheel and holder shown in FIG. 2, and FIG. 5 is a front view of the apparatus shown in FIG. FIG. 6 is a front view of a cutting wheel according to another embodiment of the present invention, and FIG. 7 is a side view of a cutting wheel and a holder according to another embodiment of the present invention. FIG. (Explanation of symbols) 10... Cutting device 14... Cutting tool 16.18.
... Carriage (transfer device) 20 ... Control computer 34 ... Bed 65 ... Support surface 70,90
, 92... Cutting wheel 71, 91, 93... Blunt circumferential cutting edge 100... Load control mechanism S... Sheet material patent applicant Gerber Garment Technology (
2 people outside)

Claims (1)

[Scope of Claims] 1. A support having a support surface G that can be expanded to cut sheet material; Rolling blunt circumferential cutting edge (71,
a cutting tool I having a cutting wheel (70, 90 or 92) with a cutting wheel (70, 90 or 92) and a cutting wheel (70, 90 or 92) for controllingly moving the cutting wheel along the desired cutting line of the sheet material relative to the supporting surface; It consists of a transfer control mechanism (16, 18) connected to the cutting tool and the support, and a load mechanism (9) for pressing the blunt cutting edge of the cutting wheel against the support surface. A sheet material cutting device characterized in that, as it is moved, the cutting operation is accomplished by crushing the sheet material between the blunt cutting edge of the cutting wheel and the supporting surface.2. a thin disc with a substantially uniform thickness between the wheels, and the blunt circumferential cutting edge of the wheel has a radius of curvature greater than half the thickness of the wheel between its axial sides; The sheet material cutting device according to claim 1, characterized in that the thickness of the cutting wheel is small compared to the diameter of the wheel, and the diameter of the wheel is between 0.25 and 6 inches (6 inches). ,35
76.211111). 4. The blunt cutting edge of the cutting wheel is 0.001-0.010
A sheet material cutting device according to claim 1, characterized in that it has a radius of curvature within the range of inches (0.025 to 0.2541 EII). 5. The sheet material cutting device according to claim 1, wherein the blunt cutting edge of the cutting wheel has a substantially infinite radius of curvature. 6. The sheet material cutting device according to claim 1, wherein the blunt cutting edge of the cutting wheel is flat. 7. The flat cutting edge is 0.002-0.005 inch (0,
7. A sheet material cutting device according to claim 6, characterized in that it has a width in the range of 0.050 to 0.1271). 8. The flat cutting edge of the wheel has a width selected to cut the sheet material under the force of the loading mechanism without damaging the supporting surface. Sheet material cutting equipment as described. 9. Sheet material cutting device according to claim 1, characterized in that the support surface has a hardness less than that of the cutting wheel.