JPH0455803B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cutting device comprising a cutting head which can be moved up and down and which holds a cutting blade for cutting a workpiece placed on a base. More specifically, when the cutting head descends from an elevated position and the cutting blade cuts into the material to be cut, the thrust force that acts on the cutting blade as cutting resistance is always kept almost constant. The present invention relates to a device for controlling the cut of a cutting blade into a material to be cut.

A horizontal bandsaw machine, which is well known as an example of a cutting device, is equipped with a base on which the material to be cut can be placed and fixed, and an endless bandsaw blade as a cutting blade is mounted on this base so that it can rotate freely. A cutting head is provided that is hung around the wheel and the driven wheel and is movable up and down. The band saw blade is guided and supported by a pair of guide members provided in the cutting head so that the tip of the band saw blade faces vertically downward in the cutting area where the material to be cut is cut. Further, the cutting head is provided so as to be able to rise and fall freely around a horizontal hinge pin or along a vertical guide post by the action of a lifting cylinder interposed between the cutting head and the base. . Therefore, after the cutting head is raised by the action of the lifting cylinder, the drive wheel is rotated to run the band saw blade, and then the pressure oil in the lifting cylinder is discharged, so that the cutting head is free from its own weight. The band saw blade descends, and the band saw blade cuts into the material to be cut, thereby cutting the material.

In the conventional cutting device with the above configuration,
A discharge passage is connected to the chamber on the piston side of the lifting cylinder for raising and lowering the cutting head.
By controlling the discharge of pressure oil from this discharge path, the lowering of the cutting head, in other words, the cutting of the cutting blade into the material to be cut is controlled. By the way, in the past, a pressure reducing valve of a constant differential pressure type was disposed in the discharge passage, and a flow rate control valve was disposed on the rear side thereof. Therefore, conventionally, when cutting a material to be cut, the length of the portion of the material to be cut cut by the cutting blade (cutting length) changes,
Even if the pressure acting on the cutting blade and the pressure in the chamber on the piston side of the lifting cylinder and the discharge passage change, and the secondary pressure of the pressure reducing valve becomes, for example, 1/2, the pressure will change. According to the relational expression with flow rate, the flow rate of oil passing through the flow control valve is 1/2
It does not change by only 1/√2.
Therefore, an unreasonable load is applied to the cutting blade, resulting in problems such as the cutting blade being liable to break or bend.

This invention was created in view of the above-mentioned conventional problems, and its first purpose is to maintain the thrust force acting on the cutting blade almost constant when cutting the material to be cut. An object of the present invention is to provide a cutting depth control device for a cutting device capable of cutting materials.

A second object of the present invention is to provide a cutting control device that can cut a workpiece without applying an unreasonable load to the cutting blade.

In order to achieve the above objects, in the present invention, the opening degree of the discharge passage of the lifting cylinder that lifts and lowers the cutting head equipped with the cutting blade is applied to the cutting blade when cutting the material to be cut. It is designed to automatically adjust according to the magnitude of the thrust force applied.

Hereinafter, one embodiment of the present invention will be described in detail using the drawings.

FIG. 1 shows a horizontal bandsaw machine as an example of a cutting device. However, the present invention is not limited to horizontal band saws, but can also be applied to various cutting devices such as circular saws and disc cutters.

Referring to FIG. 1, a horizontal bandsaw machine as an example of a cutting device is composed of a box-shaped base 3 and a cutting head 5, and the cutting head 5 is connected to the base 3 via a horizontal hinge pin 7. It is pivoted so that it can be raised and lowered. A work table 9 on which a workpiece W to be cut can be freely placed is provided on the upper part of the base 3, and the work table 9 is equipped with a fixed jaw 11f and a movable jaw 11m that can freely hold and fix the workpiece W. A vice device 11 is provided.

The cutting head 5 has housing parts 13 and 15 spaced apart from each other on both sides, and each housing part 13 and 15 has a control box 1 on its upper part.
They are connected by a beam member 17 with 9. The housing part 1 of the cutting head 5
A drive wheel 21 and a driven wheel 23 are rotatably installed inside the drive wheel 21 and the driven wheel 23 via shafts 25 and 27, respectively, and the drive wheel 21 and the driven wheel 23 are provided with an endless bandsaw blade 29 as a cutting blade. is hanging around. Therefore, the band saw blade 29 is driven to travel by driving the drive wheel 21 in order to cut the material W to be cut.

In the cutting region where the band saw blade 29 cuts the material W to be cut, the band saw blade 29 is guided and supported by a pair of fixed guide member 31 and movable guide member 33 so that the tips of the teeth face vertically downward. The fixed guide member 31 and the movable guide member 33 are attached to a guide member 35 fixed to the beam member 17. The fixed guide member 31 is the guide member 3
The movable guide member 33 is fixedly attached to the movable guide member 33.
is attached so that its position can be adjusted freely to correspond to the size of the material W to be cut. Further, the cutting head 5 is configured to be rotated up and down about the hinge pin 7 by a lifting cylinder 37 equipped with a piston rod 39, and by the action of the lifting cylinder 37, the bandsaw blade 29 is moved against the material W to be cut. It is possible to control the depth of cut and upward separation.

That is, in the known horizontal bandsaw machine (cutting device) having the above structure, the cutting head 5 is raised by supplying pressurized oil to the chamber on the piston side of the lifting silander 37 to extend the piston rod 39. It is something. By discharging the pressure oil in the chamber on the piston side of the lifting cylinder 37, the cutting head 5 is lowered by its own weight. Therefore, by disposing a suitable control valve in the discharge passage connected to the piston-side chamber of the lifting cylinder 37 and adjusting the control valve as appropriate, the band saw blade 2 can be adjusted to the material W to be cut.
9 (cutting blade) can be controlled appropriately.

By the way, the pressure receiving area on the piston rod side of the lifting cylinder 37 is A ₁ , the pressure receiving area on the piston side is A ₂ , the pressure on the piston rod side is P ₁ , the pressure on the piston side is P ₂ and the cut acting on the lifting cylinder 37 is Assuming that the weight of the cutting head 5 is G, when the workpiece W is not being cut, the following formula holds true: P ₂ ×A ₂ =P ₁ ×A ₁ +G (1). Here, when the band saw blade 29 cuts into the workpiece W by lowering the cutting head 5 and starts cutting, a back force F acts on the band saw blade 29 as cutting resistance, and the following equation holds true.

P ₂ ×A ₂ +F=P ₁ ×A ₁ +G …(2) From equation (2), P ₂ =P ₁ ×A ₁ /A ₂ +G/A ₂ −F/A ₂ …(3) Here , P ₁ ×A ₁ /A ₂ +G/A ₂ =CF/A ₂ =f, then P ₂ =C−f (4).

As is clear from equation (4), when the thrust force F is large (heavy cutting), the pressure P ₂ becomes small. Therefore, by setting the pressure _P2 to a certain value (cutting condition), the thrust force F becomes constant, and the workpiece W can be cut while the thrust force is constant.

In order to cut the workpiece W under a constant thrust force as described above, in the embodiment of the present invention, the second
The circuit configuration is as shown in the figure. That is,
A first oil passage 41 connected to the pressure source P, a second oil passage 43 (also serving as a discharge passage) connected to a chamber on the piston side of the lifting cylinder 37, and a chamber on the piston rod side of the lifting cylinder 37. Between the third oil passage 45 and the first and second solenoid
A 4-port 3-position solenoid valve SV with SOL1 and SOL2 is installed. Said second oil passage 4
3, a cut control valve 47 and a filter 49 are arranged in series, and a check valve 51 is connected in parallel to the cut control valve 47. A filter 55 and an orifice 57 are connected in series to a branch passage 53 branched from the first oil passage 41, and the branch passages 59 and 61 branched into two through the orifice 57 are controlled by the cutting control. It is connected to valve 47. That is, the cutting control valve 47 is connected to the second oil passage 43 at ports A and C, and to the branch pipes 59 and 61 at ports B1 and B2. Note that in the above configuration, the third oil passage 45
is not necessarily necessary and can be omitted in some cases.

Next, details of the cutting control valve 47 will be explained using FIGS. 3 and 4.

The block-shaped valve body 63 of the cut control valve 47 is provided with a first through hole 65 and a second through hole 67 that penetrate in the vertical direction in FIG. The first
A plate 69 and a second plate 71 are fixed with bolts or the like. A lower portion of the first through hole 65 communicates with the port A formed in the valve body 63, and an upper portion thereof communicates with the port B2. is in contact with the second plate 71, and a sleeve tube 73 whose other end extends between the communication portions of ports A and B2 is fitted therein. A notch 75 is formed on the outer circumferential surface of this sleeve pipe 73 facing the port A bored in the valve body 63, and a peripheral wall 77 formed thin due to the provision of this notch 75 has the following features: As shown in FIG. 4, a substantially triangular opening 79 is formed. Further, a V-shaped communication groove 81 communicating with the notch 75 is formed on the circumferential surface and one end of the sleeve tube 73. Further, the sleeve pipe 73 includes a communication hole 83 and a through hole 8 that communicate with the port C bored in the valve body 63.
5 is perforated.

A spool valve 87 for adjusting the degree of opening of the opening 79 is slidably inserted into the sleeve pipe 73. The spool valve 87 has a configuration in which a piston portion 87P at one end and a valve body portion 87V at the other end, which can freely throttle the opening 79, are connected by a small diameter connecting portion 87C. With the above configuration, the spool valve 87 is connected to the first pressure chamber 8 on the piston portion 87P side.
9 and the pressure in the second pressure chamber 91 which is common to the first through hole 65 on the side of the valve body portion 87V causes the valve body portion 87V to slide in the axial direction. In other words,
The first pressure chamber 89 includes a communication groove 81 of the sleeve pipe 73,
It communicates with port A through the notch 75, and the second
Since the pressure chamber 91 communicates with the port B2, the spool valve 87 slides in the axial direction due to the pressure difference between the pressure in the port A and the pressure in the port B2, and adjusts the degree of opening of the opening 79. Different.

A push rod 95 slidably supported by a support tube 93 held by the first plate 69 is fitted into the second pressure chamber 91 (on the upper end side of the first through hole 65). The inner end portion of the spool valve 87 is close enough to be able to come into contact with the valve body portion 87V of the spool valve 87. Above push rod 95
A bullet 99 is mounted between a flange 97 provided near the inner end of the sleeve tube 73 and the sleeve tube 73, and the shell rod 95 is always urged outward. The outer end of the push rod 95 is in sliding contact with a cam surface 103 formed on the adjustment handle 101. That is, the end cam 10 is connected to the fixed shaft 105 implanted in the first plate 69 via the bearing 107.
9 is rotatably supported, and this end cam 1
The cam surface 103 of 09 is connected to the push rod 9.
It is in sliding contact with 5. Also, the end cam 1
09 has a grip 111 fixed to it.

Therefore, by rotating the adjustment handle 101 in an appropriate direction, the push rod 95 is moved in the axial direction, and the inner end of the push rod 95 also restricts the sliding range of the spool valve 87 toward the push rod 95 side. Become. Therefore, the maximum opening degree of the opening 79 can be adjusted.

The second through hole 67 includes a large diameter hole 67L and a small diameter hole 67S, and the small diameter hole 67S communicates with the through hole 85 of the sleeve tube 73 via a communication hole 113. A valve seat member 115 is fitted into the end of the small diameter hole portion 67S, and a small hole 115H provided in the valve seat member 115 communicates with the port B1 formed in the second plate 71. . A conical poppet valve 117 that can be freely engaged with the small hole 115H of the valve seat member 115 is engaged in the small diameter hole 67S, and a bullet 119 is disposed between the poppet valve 117 and the push rod 95'. is loaded with ammunition. Therefore, the poppet valve 117 is always pressed toward the valve seat member 115. The configuration of the push rod 95' etc. is the same as that of the aforementioned push rod 95 etc., and the configuration of the adjustment handle 101' etc. for adjusting the position of the push rod 95' is the same as that of the aforementioned adjustment handle 101 etc. Therefore, constituent members that perform the same function will be represented by the same reference numerals with a dot and a detailed explanation thereof will be omitted.

With the above configuration, by operating the adjustment handle 101' and adjusting the position of the push rod 95', the stored force of the ammunition 119 is adjusted, and the biasing force of the poppet valve 117 against the valve seat member 115 is adjusted. becomes. Therefore, the valve seat member 11
Port B1 communicates with the pore 115H of No. 5, branch pipes 59 and 61, and port B1 through port B2.
The pressure in the second pressure chamber 91 communicating with the second pressure chamber 91 is adjusted by the adjustment handle 101'.

In the above configuration, the solenoid valve
When the first solenoid SOL1 of SV is energized, the first
The oil passage 41 and the second oil passage 43 are connected. Therefore, pressure oil from the pressure source P reaches the lifting cylinder 37.
The piston rod 39 is extended and the cutting head 5 is opened.
is raised. When the cutting head 5 is in the raised state, the workpiece W to be cut is fixed by the vise device 11 and the band saw blade 29 is driven to travel. Before lowering the cutting head 5 to cut the workpiece W, the adjustment handles 101, 101' is operated to adjust and set the movement range of the spool valve 87 (maximum opening degree of the opening 79) and the pressure in the second pressure chamber 91 as appropriate. After that, solenoid valve SV
When the second solenoid SOL2 is excited,
Since the second oil passage 43 is connected to the tank T, the pressure oil in the chamber on the piston side of the lifting cylinder 37 is discharged through ports A and C of the cutting control valve 47, and the cutting head 5 is lowered. Become. Therefore, the bandsaw blade 29 cuts into the material to be cut W, and the material to be cut W is cut.

As described above, when the cutting head 5 descends, the distance to the position where the band saw blade 29 cuts into the workpiece W in the shape of a round bar (the position of the line L1 in FIG. 5) corresponds to the total weight of the cutting head 5. The load applied to the chamber on the piston side of the lifting cylinder 37 increases the pressure in that chamber and the communicating port A.
P ₂ is greater than the set pressure P ₃ in the second pressure chamber 91. Therefore, a large pressure _P2 acts in the first pressure chamber 89 through the communication groove 81, and the spool valve 87 is forced to move due to the pressure difference.
In FIG. 3, it is moved upward and comes into contact with the push rod 95, and the opening degree of the opening 79 becomes the set maximum opening degree. Therefore, a large amount of pressure oil flows out from port A to port C, and the lowering speed of the cutting head 5 becomes a preset relatively high lowering speed.

Next, when the band saw blade 29 descends to the position of the line L1 and starts cutting the workpiece W, the band saw blade 29
Thrust force acts as cutting resistance. Since this thrust force increases in proportion to the increase in cutting length L, the pressure _P2 gradually decreases. Therefore, until the pressures P ₂ and P ₃ become equal (up to the position of line L2 in FIG. 5), the spool valve 87 is in contact with the push rod 95, and the band saw blade 29 is in contact with the workpiece W. The depth of cut is the adjustment handle 10.
This is carried out at a descending speed preset by No. 1.

When the bandsaw blade 29 reaches the position of the line L2, the pressures P ₂ and P ₃ become equal, and the pressures at both ends of the spool valve 87 are in an equilibrium state. Thereafter, when the band saw blade 29 cuts into the material to be cut W, the cutting length L becomes longer and the thrust force becomes larger, so that the pressure P ₂ becomes smaller than the pressure P ₃ . Therefore, due to the pressure difference, the spool valve 87
is slid downward in FIG. 3, and the opening 79 is narrowed by the spool valve 87. When the opening 79 is narrowed, the material to be cut W
The cutting speed of the band saw blade 29 relative to the cutting speed becomes slower. When the cutting speed becomes slower in this way, the cutting depth becomes smaller and the thrust force decreases, so that the pressures P ₂ and P ₃ become equal again.

After the pressures P ₂ and P ₃ become equal again as described above, when the band saw blade 29 further cuts into the workpiece W, the pressure P ₂ becomes smaller than the pressure P ₃ again, and the spool valve 87 is lowered further. direction, and the cutting speed of the band saw blade 29 into the workpiece W further becomes slower. That is, from the position of line L2 to the position of line L3 where cutting length L is maximum, the thrust force gradually increases in proportion to the increase in cutting length L, so the pressures P ₂ and P ₃ are equal to P ₂ ＜P ₃ and P ₂
In other words, while repeating the state ＝P ₃ , P ₂
The spool valve 87 gradually moves downward while maintaining the balance of = _P3 . Therefore, the cutting speed of the band saw blade 29 into the material W to be cut gradually becomes slower while the thrust force remains constant.

From the line L3 to the line L4 position, the cutting length L gradually decreases, contrary to the line L2 position to the line L3 position, so the thrust force gradually decreases. Therefore, the pressures P ₂ and P ₃ are
While repeating the states of P ₂ > P ₃ and P ₂ = P ₃ , in other words, while maintaining the balance of P ₂ = P ₃ , the spool valve 87 gradually moves upward, and the band saw blade 29 cuts the material W to be cut. The loading speed gradually increases while the thrust force remains constant.

The cutting speed of the band saw blade 29 into the material to be cut W between the line L4 and the line L5 becomes a preset descending speed, as in the case between the line L1 and the line L2.

In addition, by operating the adjustment handle 101' and setting the pressure _P3 to an extremely small value, the spool valve 87 is kept in contact with the push rod 95 at all times, thereby making it possible to control the cutting speed at a constant level. It is. Therefore, it can also be applied to difficult-to-cut materials that require cutting at a constant cutting speed.

As can be understood from the above description of the embodiments, according to the present invention, the back force acting on the band saw blade (cutting blade) can be kept almost constant over almost the entire cutting surface of the material to be cut. , without putting excessive load on the blade.
Optimal cutting can be performed.

Note that the present invention is not limited to the above-described embodiments, but can be implemented in various other forms by making appropriate changes.

[Brief explanation of the drawing]

FIG. 1 is a front view of a horizontal bandsaw machine as a type of cutting device. FIG. 2 is an explanatory diagram of a control circuit that controls the lifting and lowering of the cutting head. FIG. 3 is a sectional view of the cutting control valve. FIG. 4 is a side view of the sleeve tube. FIG. 5 is an explanatory diagram of the cutting action. (Explanation of symbols representing main parts of drawings), 5
... cutting head, 29 ... cutting blade, 37 ... lifting cylinder, 47 ... cutting control valve, 79 ... opening, 87 ... spool valve.

Claims (1)

[Scope of Claims] 1. A lifting cylinder 37 for lifting and lowering the cutting head 5, which is equipped with a cutting blade 29 for cutting the material W to be cut, is provided, and when the cutting head 5 is lowered, the cylinder 37 for lifting and lowering the cutting head 5 is provided. A cut control valve 47 is arranged in the discharge path of pressure oil discharged from the cylinder 37.
In the hole 65 provided in the valve body 63 at 7,
A spool that can adjust the degree of opening of an opening 79 provided in a communication path between port A, which is connected to the cylinder 37 side and is provided in the valve body 63, and port C, which is connected to the tank T side and is provided in the valve body 63. A valve 87 is slidably provided internally, and the port A connected to the cylinder 37 side is connected to the first pressure chamber 89 on one end side of the spool valve 87, and the first pressure chamber 89 on the other end side of the spool valve 87 is connected to the The pressure P ₃ in the second pressure chamber 91 can be set arbitrarily, and the spool valve is controlled by the pressure difference between the pressure P ₂ in the first pressure chamber 89 and the pressure P ₃ in the second pressure chamber 91. 87 is provided in a sliding configuration, and the pressure P ₂ in the first pressure chamber 89 is
cutting control in a cutting device, characterized in that the spool valve 87 is slid in a direction to increase the opening degree of the opening 79 when the pressure P _{3 in the second pressure chamber 91 is greater than the pressure P 3} in the second pressure chamber 91; Device. 2. The cutting control device according to claim 1, characterized in that a position regulating member 95 that can freely regulate the sliding range of the spool valve 87 is provided in the second pressure chamber 91 in a position adjustable manner. .