JPH01121119A - Band saw rocking controller for band sawing machine - Google Patents

Abstract

PURPOSE:To form a controller into compact in size and simple in mechanism as a whole as well as to prevent any damage to a band saw from occurring by varying backup hydraulic pressure to increase or decrease alternately with work of an automatic relief pressure regulating mechanism, and having the band saw seesawed. CONSTITUTION:At the time of cutting down control over a head 1, relief pressure in relief valves 37, 38 installed in a drain passage of compressed oil to be delivered out of a head lifting booster cylinder 7 is repeated in a state of making its increase or decrease variation reverse to each other by a relief pressure regulating mechanism 39, and a band saw 2a between driving and driven wheels 3, 4 is seesawed with a lowering of the head 1. Then, full cutting length in a workpiece W is divided into two parts, right and left, and alternate cutting takes place. Thus, the whole device can be miniaturized and simplified in structure, while when overload acts thereon, the drain passage out of the head lifting hydraulic cylinder is automatically throttled, so that chipping and breakdown of the band saw can be obviated.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention provides a band saw machine that cuts a workpiece by moving a rotating band saw close to an object to be cut. The present invention relates to a control device for controlling the

(Prior art and its problems) This type of band saw machine cuts a workpiece whose transverse length in the band saw length direction changes with respect to the cutting direction, such as a cylindrical workpiece. In some cases, the cutting length of the band saw changes significantly as the cutting progresses. When the cutting action length of the band saw changes in this way, it is necessary to automatically adjust the cut feed rate of the band saw in accordance with the change in the cutting action length to avoid applying an excessive load to the band saw. It is known that reducing the cutting feed speed of a band saw causes slipping of the saw teeth and slight vibration of the band saw.

In order to solve these problems, it has been considered to lower the band saw while performing swing motion in an arc back and forth in the cutting direction along the cutting surface. According to this method, the cutting action length of the band saw can be shortened even in a wide area during cutting, and the above-mentioned problems can be solved. A very complicated mechanism is required to mechanically swing the head, which not only increases the size of the entire device and significantly increases costs, but also causes problems such as being prone to breakdowns and not being easy to maintain. there were.

(Means for Solving the Problems) The present invention proposes a band saw swing control device for a band saw machine that can solve the conventional problems as described above. Two throttle control valves each have a spool that throttles the throttle flow path by moving backwards.
disposed on the head so that the spool receives cutting reaction forces acting on the band saw on both sides of the cutting position;
A flow path for supplying backup hydraulic pressure to each of the control valves by interposing throttling flow paths for both of the control valves in parallel in a drain flow path for pressure oil sent out from a head raising hydraulic cylinder when the head is lowered for cutting M. A relief valve is connected to each of the passages, and an automatic relief pressure adjustment mechanism is provided for automatically and repeatedly increasing and decreasing the relief pressure of both relief valves in a state where the increases and decreases are opposite to each other.

(Example) An example of the present invention will be described below based on the attached illustrative drawings.

In FIG. 1, 1 is a head, and an endless bandsaw 2
comprising a driving wheel 3 and a driven wheel 4 for hanging the
One end is supported on a base 6 by a support shaft 5 so as to be able to swing up and down, and the other end is supported on the base 6 via a hydraulic cylinder 7 for raising the head.
is supported by

The free end of this head lifting hydraulic cylinder 7 has a support shaft 8a.
The free end of the piston rod 7a is rotatably connected to the head 1 via a support shaft 8b. The head 1 is provided with guide arms 9 and 10 of the band saw 2 at two places on the left and right between both wheels 3 and 4, and the cutting action area 2a of the band saw 2 is provided at the lower part of each guide arm 9 and 10 along a vertical plane. A guide block 11.12 is mounted to restrict the direction. Also, on the base 6,
A moving vise 13 and a fixed vise 14 that fix the workpiece W
and is provided.

In both guide blocks 11.12 there is a control valve 15A.
, 15B is installed inside. As shown in FIG. 2, both control valves 15A and 15B include a spool 16 that can be raised and lowered, and a backup hydraulic chamber 17 that urges this spool 16 downward.
, and a throttle flow path 20 formed around the small diameter portion 16a of the spool 16 so as to communicate the input port 18 and the output port 19, and when the spool 16 is at the lower limit position shown in the figure, the throttle flow is As the inlet part 20a of the passage 20 is opened to the maximum and the spool 16 rises against the hydraulic pressure in the backup hydraulic chamber 17, the inlet part 20a of the throttle passage 20 is opened by the large diameter part 16b of the spool 16. It is configured to be gradually narrowed down. 21 is an oil-tight sealing material.

A backup insert 22 for receiving the back of the band saw 2 is attached to the spool 16 of both control valves 15A, 15B at its lower end protrusion 16c via a pin 22a. Furthermore, a fixed insert 23 and a movable insert 24 are provided at the lower ends of both guide plotters 11 and 12, with the band saw 2 interposed therebetween. The movable insert 24 is attached to the inner end of a pressing rod 26 that is biased inwardly by a spring 25, and the movable insert 24 is attached to the outer end of the pressing rod 26 to move the pressing rod 26 backward against the biasing force of the spring 25. An operating lever 27 equipped with an eccentric cam 27a is pivotally mounted. Therefore, the band saw 2 is normally held between the fixed insert 23 and the movable insert 24 in a slidable manner, but by pulling down the operating lever 27, the eccentric cam 27a moves the pressing rod 26 against the spring 25. Due to the forced backward movement, the space between the fixed insert 23 and the movable insert 24 widens, and the band saw 2 is released from both inserts 23, 24.

As shown in FIG. 3, the head lifting hydraulic cylinder
The head supporting hydraulic chamber 28 of No. 7 is connected to the pump 31 via a check valve 29 with an opening pilot and an electromagnetic switching valve 30, and is also connected to the pump 31 via an electromagnetic on-off valve 32 and a variable throttle valve 33. It is connected to the input ports 18 of 15A and 15B. Further, the output boats 19 of both control valves 15A and 15B are connected to the drain tank 34, and the pilot boat 17a (second
(Fig.), the pump 31 is
and to the drain tank 34 via relief valves 37 and 38, each having a variable relief pressure. The electromagnetic switching valve 30 includes a lifting switching passage 30a that supplies pressure oil from a pump 31 to the head supporting hydraulic chamber 28 of the cylinder 7 to raise the head 1, and a check valve 29 with an opening pilot. Pressure oil from the pump 31 is supplied to the opening pilot passage 29a of the check valve 2.
9, and a rapid descent switching passage 30b that connects the head supporting hydraulic chamber 28 of the cylinder 7 to the drain tank 34 via the opened check valve 29. Head support hydraulic chamber 2
8 from either the pump 31 or the drain tank 34 from the neutral position.

30b can be used.

As shown in FIG. 4, the relief valves 37 and 38 are controlled in parallel via an automatic relief pressure adjustment mechanism 39 that repeatedly increases and decreases the relief pressures of both relief valves 37 and 38 so that the increases and decreases are opposite to each other. It is set up. This relief pressure automatic adjustment mechanism 39 has a spring receiver that receives a spring 41 that biases the movable valve body 40 of the relief valve 37, 38 in the closing direction, and a seat 42 that is movable in the direction of movement of the movable valve body 40. At the same time, the spring receiver is attached to the seat 42.
A cam driven part (roller, etc.) 43 is arranged on the outside of the relief valve 37, 38, and an eccentric rotating cam 44 driven by a motor with a speed reducer (not shown) is arranged at an intermediate position between the cam driven parts 43 of both relief valves 37 and 38. The eccentric rotating cam 44
By rotating , the spring receivers of both relief valves 37 and 38 can press and move the seats 42 alternately in the direction of compressing the spring 41 via the respective cam driven parts 43. Therefore, when the strength (relief pressure) of the spring 41 that urges the movable valve body 40 of both relief valves 37 and 38 increases and decreases cyclically, and the relief pressure of one relief valve 37 or 38 increases, The increasing and decreasing operations are reversed so that the relief pressure of the other relief valve 38 or 37 decreases.

When the eccentric rotating cam 44 is composed of an inner eccentric cam 46 fixed to a drive shaft 45 and an outer eccentric cam 47 that can be rotated and fixed relative to the inner eccentric cam 46 as shown in the figure, By changing the eccentric phase of the outer eccentric cam 47 with respect to the inner eccentric cam 46, it is possible to increase or decrease the eccentricity of the entire eccentric rotary cam 44 with respect to the drive shaft 45, and as the eccentricity increases or decreases, both spring receivers move toward the seat 42. Since the reciprocating stroke of the eccentric rotating cam 44 will change, the amount of eccentricity of the entire eccentric rotating cam 44 will be increased or decreased.
It is possible to adjust the height difference of relief pressure at

Further, the reference relief pressures of both relief valves 37 and 38 can be adjusted by changing the initial compressive stress of the spring 41. That is, the spring receiver on the side of the movable valve body 40 is configured so that the position of the seat 48 can be adjusted in the direction of movement of the valve body by means of a screw shaft 49, and relative movement in the axial direction with respect to the screw shaft 49 is possible, but relative rotation is disabled. The rotary operation shaft 50 to be fitted is supported through the valve surface 51 so that it can only rotate.
By rotating the screw shaft 49 from the outside of the valve body 40, the spring receiver moves the seat 48 in and out, thereby increasing or decreasing the initial compressive stress of the spring 41. 52 is a lock nut for the rotary operation shaft 50.

The screw shaft 49 may be configured to directly protrude outward from the valve surface 51 so that the screw shaft 49 can be rotated directly from the outside of the valve surface 51. In this case, as the movable valve body 40 moves, the screw shaft 49 moves through the valve surface 51 in the axial direction.

In the above configuration, by switching the electromagnetic switching valve 30 from the neutral position to the state in which the upward switching flow path 30a is used with the electromagnetic switching valve 32 shown in FIG. passes through the check valve 29 to the cylinder 7.
is supplied to the head supporting hydraulic chamber 28, the piston rod 7a rises, and the head 1 is pushed up. When the head 1 reaches its upper limit, the electromagnetic switching valve 30 automatically returns to the neutral position. Furthermore, by switching the electromagnetic switching valve 30 from the neutral position to a state in which the rapid descent switching passage 30b is used, pressure oil from the pump 31 is introduced into the opening pilot passage 29a of the check valve 29, and the reverse The stop valve 29 is opened,
The head supporting hydraulic chamber 28 of the cylinder 7 is connected to the drain tank 34 via the opened check valve 29 and the steep drop switching passage 30b of the electromagnetic switching valve 30.

Therefore, the head 1 rapidly descends due to gravity while pushing out the pressure oil in the head supporting hydraulic chamber 28 of the cylinder 7.

As described above, when the electromagnetic switching valve 32 is switched from the state where the head 1 is in the raised position and the electromagnetic switching valve 30 is in the neutral position to the open state, the head supporting hydraulic chamber of the cylinder 7 is opened due to the gravity acting on the head 1. Pressure oil pushed out from inside 28 can flow to the drain tank 34 via the electromagnetic on-off valve 32, the variable throttle valve 33, and the throttle channels 20 of both control valves 15A and 15B. Then, the head 1 descends by gravity at a speed corresponding to the flow rate regulated by the throttle channels 20 of both control valves 15A and 15B. By rotating the band saw 2 in this state, the workpiece W set on the base 6 can be cut by the band saw 2, which descends while rotating. Band saw swing control is performed.

That is, pressure oil at a predetermined pressure, that is, backup oil pressure, is supplied from the pump 31 to the bank amplifier hydraulic chambers 17 of the control valves 15A and 15B via the throttle valves 35 and 36 and the pilot boat 17a, respectively, and 15A, 15B
Since the spool 16 is pushed down to the lower limit position, the upward cutting reaction force acting on the band saw 2 is transmitted to each control valve 15A, 15B via the backup insert 22 and the spool 16 on both sides of the cutting action position. The receiving is stopped by the bank amplifier oil pressure at .

The pressure of the backup hydraulic pressure acting on the spools 16 of these control valves 15A, 15B is
It is determined by the relief pressure of the relief valves 37, 38 connected to B. However, when the eccentric rotary cam 44 of the automatic relief pressure adjustment mechanism 39 is rotated at a constant speed by the drive shaft 45, both relief valves 37.3 are rotated as described above.
When the relief pressure of one relief valve 37 or 38 increases (or decreases), the relief pressure of the other relief valve 38 or 37 decreases (or increases).
Since the pressure is cyclically increased or decreased within a predetermined range so that the relief pressure is at its minimum, the back amplifier hydraulic pressure that urges the spool 16 toward the bandsaw 2 side becomes smaller than the normal cutting reaction force, causing relief. The maximum and minimum values of the relief pressures of both relief valves 37 and 38 are automatically adjusted by the automatic relief pressure adjustment mechanism 39 so that when the pressure is maximum, the backup oil pressure is larger than the normal cutting reaction force. By setting this, the band saw portion 2A or 2B, which is stopped by the spool 16 of the control valve 15A or 15B on the side where the backup oil pressure increases as the relief pressure increases, will handle the increasing bank amplifier oil pressure. The control valve 15 is pushed down against the hend door by the spool 16, which is then lowered to its lowering limit, and the control valve 15 on the opposite side, where the back amplifier oil pressure decreases as the relief pressure decreases.
The band saw part 2B or two people whose receiver is stopped by the spool 16 of B or 15A will rise relative to the head 1 while pushing up the spool 16 by the upward cutting reaction force that overcomes the backup hydraulic pressure. The rising speed at this time is faster (
There must be.

When the decreasing relief pressure (bank amplifier hydraulic pressure) reaches the minimum value, the relief pressure (backup hydraulic pressure) starts to increase again, and conversely, when the increasing relief pressure (backup hydraulic pressure) reaches the maximum value, the relief pressure (backup hydraulic pressure) increases again. starts to decrease, so the above action acts alternately on the bandsaw parts 2A and 2B on both sides of the cutting position,
As a result, the band saw 2, which descends as the head 1 descends, oscillates with respect to the workpiece W in a seesaw motion with the cutting action position as a fulcrum, and the desired oscillating cutting is performed. .

Figures 5A to 5D show this oscillating cutting, in which the backup hydraulic pressure acting on the two band saw parts on the left side of the band saw 2 shown in Figure A gradually increases, and at the same time the backup oil pressure acting on the band saw part 2B on the right side. As the amount gradually decreases, the band saw 2 performs downward cutting, centering on the left side of the workpiece W, as shown by the shaded area in Figure B. When the backup hydraulic pressure acting on the band saw section 2A becomes maximum and the backup hydraulic pressure acting on the band saw section 2B becomes minimum, conversely, the backup hydraulic pressure acting on the right band saw section 2B starts to gradually increase and the left band saw section The back amplifier oil pressure acting on 2B begins to gradually decrease, but it remains at 0.
The figure shows the state when the backup hydraulic pressure acting on both band hem portions 2A and 2B becomes equal, and in the process from figure B to figure 0, the band saw 2 descends the shaded part in figure 0. Cut. In Figure D, the backup hydraulic pressure acting on the right band saw section 2B reaches its maximum and the left band saw section 2B reaches its maximum level.
This shows the state of the band saw 2 when the backup hydraulic pressure acting on A becomes the minimum, and in the process from Fig. 0 to Fig. D, the band saw 2 cuts the workpiece W as shown by the shaded area in Fig. D. Descending cutting will be done centering on the right side.

By repeating the above action, the band saw 2 descends while making a see-saw movement, and the entire cutting length of the workpiece W can be cut while being divided alternately into the left and right sides. Of course, the degree to which the cutting length is divided can be freely adjusted by changing the descending speed of the head 1 and the one cycle time of seesaw movement of the band saw 2. One cycle time of the seesaw movement of the band saw 2 can be adjusted by changing the rotational speed of the eccentric rotating cam 44 in the automatic relief pressure adjustment mechanism 39.

In addition, in the control valve 15A or 15B' where the backup hydraulic pressure pushes the spool 16 toward the band saw 2 side against the cutting reaction force, the amount of restriction of the throttle channel 20 is reduced, and the cutting reaction force is In the control valve 15B or 15A on which the control valve 16 is moved backward against the backup hydraulic pressure, the throttle flow path 2
Since the throttle amount of 0 increases, after being pushed out from the head supporting hydraulic cylinder 7, both control valves 15A, 15B
The total drain amount of pressure oil passing through the throttle channels 20 in parallel is kept approximately constant, and the head 1 descends at a predetermined speed.

However, if the cutting reaction force acting on the band saw 2 during the cutting process becomes excessive beyond the normal value, both control valves 15A receiving the cutting reaction force of the band saw 2.

Since the spools 16 of 15B are all pushed up against the back amplifier hydraulic pressure and the amount of restriction in the restriction channel 20 increases, the total drain amount of pressure oil pushed out from the head support hydraulic cylinder 7 decreases, and the head 1 (band saw 2)'s descending speed is automatically reduced to avoid unreasonable cuts.

(Operations and Effects of the Invention) As described above, according to the band saw swing control device for a band saw machine of the present invention, the two throttles each include a spool that narrows the throttle flow path by moving backward against the back amplifier hydraulic pressure. control valve,
disposed on the head so that the spool receives cutting reaction forces acting on the band saw on both sides of the cutting position;
A flow path for supplying backup hydraulic pressure to each of the control valves by interposing throttling flow paths for both of the control valves in parallel in a drain flow path for pressure oil sent out from a hydraulic cylinder for raising the head during cutting lowering control of the head. The relief pressure of two relief valves connected to each of , by simply increasing and decreasing the backup hydraulic pressure applied to the band saw parts on both sides of the cutting operation position via the spools of the two control valves by the action of the automatic relief pressure adjustment mechanism, the band saw between the two sub-parts of the band can be operated. The entire cutting length of the workpiece can be divided into left and right sides and cut alternately by making a see-saw motion as the head descends. Similar to the conventional band saw machine that incorporates a head swing mechanism, it has become possible to obtain the effects of swing cutting.

Of course, compared to the conventional band saw machine in which the entire head is mechanically driven to swing as described above, the entire device can be made smaller and simpler, resulting in significant cost reductions and easier maintenance. become.

Further, according to the device of the present invention, the two control valves for causing the bandsaw to see-saw as described above control the drain flow path of the pressure oil sent from the hydraulic cylinder for lifting the head when an excessive load is applied to the bandsaw. Since it can automatically reduce or stop the descending speed of the head, it has the feature that it can also function as a band saw compensating means to prevent chipping or breakage of the band saw.

[Brief explanation of the drawing]

FIG. 1 is a schematic front view showing the overall configuration of the bandsaw machine, and FIG. 2 is a vertical side view showing the structure of the band saw backup control valve.
FIG. 3 is a hydraulic circuit diagram, FIG. 4 is a partially longitudinal side view showing two leaf valves and their automatic relief pressure adjustment mechanism, and FIG. 5 is a diagram illustrating the state of swing cutting. DESCRIPTION OF SYMBOLS 1... Head, 2... Band saw, 7... Hydraulic cylinder for head elevation, i5A, 15B... Band saw backup control valve, 16... Spool, 17... Backup hydraulic chamber, 20 ... Throttle flow path, 22... Backup insert, 29... Check valve with opening pilot, 30... Solenoid switching valve, 31... Hydraulic pump, 3
2... Solenoid on-off valve, 37. 38... Variable relief valve, 39... Relief pressure automatic adjustment mechanism, 40... Movable valve body, 41... Spring, 42 Movable spring support seat, 43 ...Cam driven part, 44... Eccentric rotating cam, 49... Spiral shaft for adjusting spring initial compressive stress.

Claims (1)

[Claims] In a band saw machine, a band saw is installed on a head that is supported so as to be movable in the distance direction relative to the workpiece, and the band saw is rotated while the head is moved close to the workpiece to cut the workpiece. Two throttle control valves each having a spool that narrows the throttle flow path by moving backward and moving backward are arranged on the head so that the spools receive cutting reaction forces acting on the band saw on both sides of the cutting action position. and a throttle flow path for both of the control valves is provided in parallel in a drain flow path for pressure oil sent from a hydraulic cylinder for raising the head during cutting lowering control of the head, and backup hydraulic pressure is supplied to each of the control valves. A band saw oscillation control for a band saw machine is provided with a relief pressure automatic adjustment mechanism that connects a relief valve to each flow path and automatically adjusts the relief pressure of both relief valves repeatedly to increase and decrease in a state where the increase and decrease changes are opposite to each other. Device.