CA1238564A - Press machine - Google Patents
Press machineInfo
- Publication number
- CA1238564A CA1238564A CA000461503A CA461503A CA1238564A CA 1238564 A CA1238564 A CA 1238564A CA 000461503 A CA000461503 A CA 000461503A CA 461503 A CA461503 A CA 461503A CA 1238564 A CA1238564 A CA 1238564A
- Authority
- CA
- Canada
- Prior art keywords
- ram
- press machine
- position determining
- movement
- determining member
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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- Bending Of Plates, Rods, And Pipes (AREA)
- Presses And Accessory Devices Thereof (AREA)
- Control Of Presses (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A press machine or bending press is provided in which the stop position of the ram in the vertical direction is accurately determined in a proportional relationship with the up and down motion of the ram.
The setting of the position at which the vertically moving ram is stopped can be set easily and accurately and the speed of movement of such ram can be easily controlled. Also, the position to which the ram has been raised or lowered can be readily detected.
A press machine or bending press is provided in which the stop position of the ram in the vertical direction is accurately determined in a proportional relationship with the up and down motion of the ram.
The setting of the position at which the vertically moving ram is stopped can be set easily and accurately and the speed of movement of such ram can be easily controlled. Also, the position to which the ram has been raised or lowered can be readily detected.
Description
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TITLE OF THE INVENTION
A PRESS MAC~INE
BACKGROUND OE THE INVENTION
Field of the Invention This invention relates to a press machine, more specifically, to a press machine such as a press brake used for bending sheet-like workpieces.
Description of the Prior Art As is well-known, a bending press or press machine such as a press brake for bending sheet-like workpieces such as sheet metals is provided with a pair of upper and lower bending tools one of which is so arranged as to be vertically moved by a ram toward and away from the other to bend a workpiece. Usually, the lower bending tool is fixed and the upper tool is mounted on the ram to be vertically moved toward and away from the lower bending tool, but, in some bending presses, the upper bending tool is fixed and the lower bending tool is movably held by the ram. Anyway, the workpiece to be bent is p]aced or held on the lower bending tool so that it may be bent when either of the upper and lower bending tools, which is movable, i.s vertically moved toward the other which is fixed. Also, the ram carrying the movable bending tool, in ~L~3~5~
many bending presses, is hydraulically operated by a hydraulic means to vertically move the movable bending tool toward and away from the fixed bending tool.
In such a bending press, the bending angle to ~hich the workpiece is to be bent is determined by the travelling limit of the ram which vertically moves the movable bending tool toward the fixed bending tool to bend the workpiece. Accordingly, it is necessary to accurately set the travelling limit of the ram or the movable bending tool so as to accurately bend the workpiece to a desired angle. In order to accurately control the position to which the ram is raised or lowered, in the case of a hydraulic press a control valve is installed in the hydraulic circuit to raise or lower the ram. In addition, the press machine or bending press has a position determining member which controls the position to which the ram is raised or lowered by controlling the above-mentioned control valve, and the ram has an operation member which causes the valve to open when it is contacted by the position determining member. That is, when an operation member on the ram contacts the position determining member, the vertical movement of the ram i5 stopped to control its position.
It is desirable for the position determination to be done near the center of the ram. If it is done at one end, the equilibrium of the ram can be upset resulting in large posltion error.
TITLE OF THE INVENTION
A PRESS MAC~INE
BACKGROUND OE THE INVENTION
Field of the Invention This invention relates to a press machine, more specifically, to a press machine such as a press brake used for bending sheet-like workpieces.
Description of the Prior Art As is well-known, a bending press or press machine such as a press brake for bending sheet-like workpieces such as sheet metals is provided with a pair of upper and lower bending tools one of which is so arranged as to be vertically moved by a ram toward and away from the other to bend a workpiece. Usually, the lower bending tool is fixed and the upper tool is mounted on the ram to be vertically moved toward and away from the lower bending tool, but, in some bending presses, the upper bending tool is fixed and the lower bending tool is movably held by the ram. Anyway, the workpiece to be bent is p]aced or held on the lower bending tool so that it may be bent when either of the upper and lower bending tools, which is movable, i.s vertically moved toward the other which is fixed. Also, the ram carrying the movable bending tool, in ~L~3~5~
many bending presses, is hydraulically operated by a hydraulic means to vertically move the movable bending tool toward and away from the fixed bending tool.
In such a bending press, the bending angle to ~hich the workpiece is to be bent is determined by the travelling limit of the ram which vertically moves the movable bending tool toward the fixed bending tool to bend the workpiece. Accordingly, it is necessary to accurately set the travelling limit of the ram or the movable bending tool so as to accurately bend the workpiece to a desired angle. In order to accurately control the position to which the ram is raised or lowered, in the case of a hydraulic press a control valve is installed in the hydraulic circuit to raise or lower the ram. In addition, the press machine or bending press has a position determining member which controls the position to which the ram is raised or lowered by controlling the above-mentioned control valve, and the ram has an operation member which causes the valve to open when it is contacted by the position determining member. That is, when an operation member on the ram contacts the position determining member, the vertical movement of the ram i5 stopped to control its position.
It is desirable for the position determination to be done near the center of the ram. If it is done at one end, the equilibrium of the ram can be upset resulting in large posltion error.
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The above-mentioned position determining member consists of a rotating link located on the frame side at the center of the ram along the length of the ram so that it is free to rotate up and down. The operation member on the ram is designed to contact the tip of the rotating link. The position of the ram is determined by setting the angle of the above- mentioned rotating link. Consequently, the operation member, which moves up and down, contacts the rotating link the tip of which describes a circular arc. Since there is no relation of proportionality between the position at which the rotatirg link angle is set and the position at which the ram is set to stop, it is very difficult to accurately set the position at which the ram stops in the vertical direction.
The position of the above-mentioned position determining member can be set ei-ther manually or automatically. Manual setting, which is done by rotating a handle provided on the side of the press machine, is difficult to accurately operate. Automatic setting, which is done by ON/OFF operation of a pushbutton switch on a control box, is also hard to accurately operate.
Control o~ the speed of vertically moving ram in the press machine or bending press is accomplished by opening and closing an unload valve in the hydraulic circuit that drives the ram vertically. The above-mentioned unload valve is opened and closed by stepping on a link-type foot pedal on the Eront of the press machine. This makes it impossible to ' .
operate the press machine Erom a remote location, which is a problem Erom the polnt of view of safety improvement.
There is another type of press machine or bending press in which there is a hydraulic fluid - filled cylinder under the foot pedal, and the pressure on the foot pedal is transmitted through the fluid to operate the unload valve.
However, this method also has problems: the hydraulic hose connected to the foot pedal is large in diameter and rigid, which makes operation difficult; and, when the machine is moved or transported, the foot pedal must be removed from the press machine allowing some of the hydraulic fluid to leak out and get on the floor and other nearby objècts.
Still another problem with existing press machines or bending presses is that there is no detection device to directly detect the position of -the ram which moves vertically.
SUMMARY OF THE INVENTION
This invention was conceived with a view to solving the problems described above.
The first purpose oE this invention is to provide a press machine or bending press in which the stop position o~
the ram in khe vertical movement is determined accurately in a proportional relationship with the up-and-down motion of the ram.
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The second purpose of this invention is to provide a press machine or bending press on which the setting of the position at which the vertically moving ram is stopped can be set easily and accurately.
The third purpose of this invention is to provide a press machine or bending press on which the speed of the vertically moving ram can be easily controlled.
The fourth purpose of this invention is to provide a press machine or bending press on which the position to which the ram has been raised or lowered can be easily detected.
To achieve the first of the objectives listed above, in this press machine or bending press the position ~ determining member which contacts the operation member on the ram to stop the vertical movement of the ram for position determining is adjusted by linear motion.
To achieve the second of the objectives ].isted above, the position determining member is moved by a pulse mo-tor; the control section includes a pulse generator which controls the pulse motor an~ also an indicator which indicates the position oE the position - determining member as judged from how far the pulse motor has actually moved.
To achieve the third of the objectives listed above, an electromagnetic proportional valve is installed in the hydraulic circuit which drives the ram up and down. The ; system is designed so that the speed of the vertically moving ; ram can be controlled by the control of this electromagnetic .~
.
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proportional valve corresponding to operation of a speed control device.
To achieve the fourth of ~he objectives listed above, a ram position detection device which directly detects the position to which the ram has been raised or lowered is installed.
Other and further objects and advantages of the present invention will be apparent from the following description and accompanying drawings which, by way of illustration, show preferred embodiments of the present invention and the principles thereof.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a perspective view of a press machine incorporating this invention.
Figure 2 is an enlargèd cross-sectional view taken along the line II - II in Figure 1.
Figure 3 is a view seen in the direction of the arrows III-III in Figure 2.
Figure 4 is a cross - sectional view taken along the line IV - IV in Figure 3.
Figure 5 is a partly broken and partly cross-sectional view of another embodiment of the presènt invention.
Figure 6 is an enlarged front view of the control panel shown in Figure 1.
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Figure 7 is a block diagram of the pulse motor control system.
Figure ~ is an enlarged cross-sec-tional view taken along the line VIII - VIII in Figure 1.
Figure 9 is a view seen in the direction of the arrows IX - IX in Figure 8.
Figure 10 is an enlarged cross-sectional view taken along the line X - X in Figure 1.
Figure 11 is a partially cut-away side view of the section shown in Figure 10.
Figure 12 is a cross-sectional view taken along the line XII - XII in Figure 11.
Figure 13 is a hydraulic circuit diagram.
DESCRIPTION OF THE PREFERRED_EM80DIMENT
Referring to Figure ]., a press machine or bending press 1 such as a press brake has right and left C-shaped side frames 3R and 3L, upper and lower frames 5 and 7 supported on both sides by the right and ].eft frames 3R and 3L, and a ram 9 installed inside the lower Erame 7 in an opposing relationship with the upper frame 5. An upper bending tool 11 used for bendin~ sheet-~like workpieces W is attached to the bottom of the above~mentioned upper frame 5 so that it can be removed and replaced. A lower bending tool 13 is attached to the top of the ram 9 opposite to the upper bending tool 1]. so that it ~3!356~
can be removed and replaced ~ s will be explained in more detail below, the ram g is driven up and down by a hydraulic cylinder 15 for vertical operation installed inside the lower ~rame 7. The upward movement of the ram 9 pushes the lower bending tool 13 up against the upper bending tool ll, thereby bending the work piece r .. ch is clamped between the upper and lower bending tools ll and 13. That is, in this embodiment, in order to bend the work piece W the ram 9 moves upward, but the applicability of this invention is not limited to this embodiment; this invention can also be applied in a press machine or bending press in which the ram is installed in the upper frames and moves downward to push one bending tool against the other.
Referring to Figures 2 through 4, the hydraulic cylinder 15 which drives the up-and-down movement of the above-mentioned ram 9 is built in to the lower part of the lower frame 7 having front and rear frames 7a and 7b. In this embodiment, an operation member l9 which is attached to the ram 9 operates a position determining device 17 to determine the position at which the upward movement of the ram is stopped. More specifically, the stop position determining device 17 is attached to the lower rear Erame 7b, which is located to the rear of the ram 9, through a bracket 21. The operation member l9 is located so that its tip sticks through the opening of the lower rear frame 7b to within the range of movement of a position determining member 23, which is part of ...
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the position determining device 17 and is installed so that its position can be adjusted. The system is designed so that the upward movement of the ram 9 will stop when this operation member 19 contacts the position determining member 23.
Consequently, the stop position of the ram 9 in the vertical operation can be controlled by adjusting the position of the stop position determining member 23.
As can be seen from Figures 2 through ~, the position determining member 23 is designed so that its position is adjusted by linear up-and-down motion. That is to say, two opposing guide rails 25 are mounted on the above-mentioned bracket 21i these guide rails 25 support the position determining member 23 while allowing it to move up and down.
The position determining member 23 is screwed into a threaded bolt 27 which is parallel to the guide rails 25; this threaded bolt 27 is coupled to a pulse motor PM which is mounted on the bracket 21. Consequently, by turning the threaded bolt 27 by the pulse motor PM, the position determining member 23 can be moved up and down along the guide rails 25.
In more detail, the pulse motor PM has a pulse encoder PE which detects the actual amount of rotation oE the pulse motor PM; and a rotatincJ shaft 29 oE the pulse motor PM and the lower end of the above-mentioned threaded bolt 27 are spline-coupled. In addition, the upper end o~ the threaded bolt 27 is rotatably supported by a bearing block 31, which is supported so that it is free to move up and down along the _9_ .
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above-men-tioned guide rails 25. That is, when the upward motion of the above-mentioned ram 9 pushes the operation member 19 up against the position determining member 23, the position determining member 23 and the threaded bolt 27 can move upward together as a single unit.
In order to detect the contact o~ the operation member 19 with the position determining member 23 and stop the upward motion of the ram 9, the stop position determining device 17 has a switching valve 33 which opens and closes the hydraulic circuit to the above- mentioned hydraulic cylinder 15. This switching valve 33 having a slidable spool 33S allows part of the hydraulic fluid in the above-mentioned hydraulic circuit to return to a tank when the spool 33S is pushed. One end of the spool 33S is in contact with one end 35a of a lever 35.
The lever 35 is connected to the bracket 21 through a shaft 37 so that it is free to swing. The other end 35b oE the lever 35 is in contact with the above-mentioned bearing block 31.
The above-mentioned lever 35b is always held at the other end thereof in contact with the bearing block 31 by the action of an elastic body 39' such as a torsion spring or a compression spring.
As can be understood from the mechanism described above, as mentioned above when the operation member 19 contacts the position determining member 23, the lever 35 is rotated against the resistance of the elastic body 39', and the spool 33S of the switching valve 33 is pushed against one 1238~i~4 end 35a of the lever 35, causing the switching valve 33 to operate, stopping the upward motion of the ram 9.
When the above-mentioned pulse motor PM is operated to raise or lower the above-mentioned position determining member 23, in order to detect whetner or not the position determining member 23 is in contact with the operation member 19, as is most clearly shown in Figure 3, an auxiliary lever 39 is attached to the above-mentioned lever 35 at the center -thereof and extending in an up-down direction. Dogs 41a and 41b are attached to both sides of the tip of this auxiliary lever 39 so that they can be ad~usted. The dog 41a is opposite a first limit switch LSl which is attached to a mounting plate 43 which is fixed to the bracket 21. The other dog 41b is opposite a second limit switch LS2 which is also attached to the mounting plate 43. That is to say, the tip of the auxiliary lever 39 is located between the limit switches LSl and LS2.
In the above configuration, as has already been discussed when the operation member 19 contacts the position determininy member 23, the lever 35 rotates causing the normally closed contact oE the second limit switch LS2 to open; thus the contact oE the operation member 19 with the position determininy member 23 is detected.
When an instruction to the pulse motor PM starts the pulse motor PM rotating in such a direction as to turn the threaded bolt 27 in a direction that drives the position ~2~35~
determining member 23 downward, the position determining member 23 contacts the operation member 19. In addition, when the threaded rod 27 rotates in such a direction as to advance downward, the bearing block 31 rises and the lever 35 rotates pushing the spool 33S of the swtiching valve 33. If the spool 33S of the switching valve 33 is pushed farther than necessary, the first limit switch LS1 switches ON and the rotation commands to the pulse motor Pl~ stop. In this way the rotation of the threaded bolt 27 shows that the position determining member 23 cannot go down any farther.
A third limit switch LS3 is attached to the bracket to detect when the position determining meber 23 has reached its upper limit. A dog 45 is attached to the position determining member 23 so that it can be freely adjusted, in order to operate the third limit switch LS3. Consequently, when the third lirnit switch LS3 has been operated, it is knowrl that the position determining member 23 cannot be moved up any farther.
Figure 5 shows another embodiment in which the threaded bolt 27 operates the switching valve 33 directly. In this embodiment, a driven pulley 49 is rotatably supported by a bearing block 47, which is attached to the switching valve 33.
The upper tip oE the threaded bolt 27 is spline-coupled to this driven pulley ~9. In addition, the threaded bolt 27 i.s connected to the spool 33S oE the switching valve 33 through a sliding pin 51. A belt 53 connects the driven pulley 49 to a driving pulley 55 which is in turn driven by the pulse motor PM.
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Since this embodiment operates in a slmilar manner to the embodiment discussed above, like members havin~ similar functions are designated by like numbers, and the detailed explanation is omitted here.
It should be noted that this invention can be used in a number of different embodiments. For example, the position determining member 23 could have a slanted surface which the operation member 19 would contact, and a component of the force would move the position determining member 23.
configuration in which the position determining member 23 is adjusted by horizontal movement is also possible.
Referring again to Figure 1, the press machine 1 has a control panel 57 which controls the press machine 1 and the pulse motor PM. More specifically, a control box 59 is moun-ted on either one of the above-men-tioned right and left side frames 3R and 3L as appropriate. Mounted on this control box 59 is a supporting column 61 which sticks straight up and is free to rotate. This supporting column 61 in turn supports at the upper portion thereof the base of an arm 63 which can be adjusted by expansion and contraction. Rotatably depending from the tip of this arm 63 is a support bar 65, at the lower end of which is supported the control panel 57. Thus, the position of the control panel 57 can be acljustecl arbitrarily throuyh a fairly wide ranye.
As shown in detail in Figure 6, the control panel 57 has a manual pulse generator 67 for operating the ., .
~L~385~4 above-mentioned pulse motor PM and a position indicator 69 which receive~s the pulse signals from the above-mentioned pulse encoder PE and indicates the position of the position determining member 23. The control panel 57 also has an origin setting button 71 which sets as the origin the position to which the ram 9 has risen when the above-mentioned upper bending tool 11 and lower bending tool 13 are in direct contact to generate a predetermined pressure between them, a lower limit position setting switch 73 which can set the lower limit position of the ram 9 to any desired value, and a speed conversion position setting switch 75 which automatically changes the rising speed of the ram 9 at an arbitrarily selected position. The above-mentioned lower limit position setting switch 73 and speed conversion position setting switch 75 are digital switches, and their settings can be changed arbitrarily.
The above-mentioned manual pulse generator 67 might, for example, be a pulse encoder. When a knob 67N is turned, pulses correspondiny to the speed are generated. As shown in Figure 7, this manual pulse generator 67 is connected to a motor driver 77, which drives the above-mentioned pulse motor PM, through a rotation direction discrimination circuit 79.
Connected to the motor driver 77 are an auxiliary switch 81, which overrides input from the manual pulse generator 67, even when rotated, and prevents the pulse motor PM from turning, and the limit switches LSl and I.S3 which detect when the ... .
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position determining member 23 has reached its moving limits.
Consequently, when the auxiliary switch 81 and the limit switches LSl and LS3 are all closed, turning the knob 67N of the manual pulse generator 67 in the forward or reverse direction causes the pulse motor PM to turn in the forward or reverse direction at a rate corresponding to the speed. In this way the position of the above-mentioned position determining member 23 is adjusted.
The turning of the above-mentioned pulse motor PM is detected by the pulse encoder PE. This pulse encoder PE is connected to a counter 83 which counts the pulses from it.
The value of the count is used by the position indicator 69 to give a digital indication of the position oE the above-mentioned position determining rnember 23. The counter 83 is cleared by the origin switch SW when the origin oE the ram is to be set.
Consequently, by operating the manual pulse generator 67 while watching the position indicator 69, the position of the position determining member 23 can be set accurately, which also means that the position at which the ram 9 will stop rising is determined accurately. Since the actual rotation oE the pulse motor PM during the rotation of pulse motor is detected by the pulse encoder PE, the position oE the position determining member 23 is always indicated accurately even iE a step out problem occurs, for example if the knob 67N
oE the manual pulse generator 67 is turned too fast and the . . .
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~23~ 4 pulse motor PM can't keep up, or there are large load fluctuations beyond the capability of the pulse motor PM to follow. The pulse motor PM can be operated in either the forward or reverse direction automatically, without using the manual pulse generator 67, by connecting it to another suitable pulse generator.
Referring to Figures 8 and 9, the press machine 1 has a position detecting system 85 to detect the vertical position to which the above-mentioned ram 9 has been raised or lowered.
More specifically, the position detecting system 85 comprises a position detector 87, such as a linear encoder, which is mounted on the lower rear frame 76, and a detection member 89 which is mounted on this position detector 87 so as to be able to move up and down freely. The upper tip of this detection member 89 is coupled to a coupling block 93, which is attached to the ram 9, through a suitable elastic body 91. In this embodiment the elastic body 91 is a plate spring with a 90 twist. A lower limit dog 95 is fixed to the above-mentioned coupling block 93 so that its position can be adjusted up and down ~reely. Mounted on the lower rear Erame 76 is a forth limit switch LS~, which is operated by the lower limit dog 95 when the ram 9 has been lowered to its lower limit position.
In the configuration described above, the detection member 89 and the ram 9, which are coupled, move up and down together, and pulses corresponding to the amount oE vertical motion of the ram 9 are generated by the position detector 87.
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Conse~uently, by counting the above-mentioned pu].ses, the position to which the ram 9 has been raised or lowered can be detected and the necessary switching performed at the positions set by the lower limi~ position setting switch 73 and the speed conversion position setting switch 75.
When the ram 9, lowering from its raised position, reaches the positlon which has been set by the lower limit position setting switch 73, its lowering movement stops. When the ram 9, rising from its lowered position, reaches the position which has been set by the speed conversion position setting switch 75, the rising speed of the ram 9 is switched Erom fast to slow.
When the ram 9 moves up or down and its position is detected by the above-mentioned position detector 87 as discussed above, if errors occur in the positions o:E the surfaces of -the coupling block 93 connected to the elastic body 91 and to the detector 87, or if the ram 9 is deformed when the workpiece W is bent, the error can be absorved by deformation of the elastic body 91. That is to say, in the configuration described above the position to which the ram 9 is raised or lowered can be detected accurately.
Referring again to Figure 1, the above-mentioned control box 59 is connected to a foot pedal unit 99 through a cable 97. The Eoot pedal unit 99 can be positioned anywhere within a fairly wide range with respect to the above-mentioned control panel 57. The foo-t pedal unit 99 controls the speed 123~5~
of the above-mentioned vertically moving ram 9O It has a pedal 101U for upward movement and a pedal 101L for downward movement.
As is shown best in Figures 10 through 12, the ~oot pedal unit 99 is contained in a box 105 which has an opening 103 on one side for inserting toes. This box 105 is made in one piece with a casing 109 which has a handle 107 on the top thereoE. Inside this casing 109 are a pair of vertically moving rods 113U and 113L supported by a side bracket 111, inside the box 105, so that they can move up and down freely, and in addition a potentiometer 115 is mounted in a vertical position.
A disc-shaped stop member 117 is integrally mounted to an operation rod 115R of the above-mentioned potentiometer 115. The operation rod 115R is always pushed upward by the action of a spring 119 compressed between this stop member 117 and the bracket 111. Operation pieces 121U and 121L, which are ~ree to contact the upper surface of the above-mentioned stop member 117, are attached to the above-mentioned vertically moving rods 113U and 113L. In addition, these vertically moving rods 113U and 113L are always biased upward by the action of springs 123U and 123L.
The diameters of the vertically moving rods 113U and 1131, are reduced at their lower tips. Limit switches LSU and LSL are mounted in positions corresponding to these narrowed tips. In addition, rollers 125U and 125L are attached to the
The above-mentioned position determining member consists of a rotating link located on the frame side at the center of the ram along the length of the ram so that it is free to rotate up and down. The operation member on the ram is designed to contact the tip of the rotating link. The position of the ram is determined by setting the angle of the above- mentioned rotating link. Consequently, the operation member, which moves up and down, contacts the rotating link the tip of which describes a circular arc. Since there is no relation of proportionality between the position at which the rotatirg link angle is set and the position at which the ram is set to stop, it is very difficult to accurately set the position at which the ram stops in the vertical direction.
The position of the above-mentioned position determining member can be set ei-ther manually or automatically. Manual setting, which is done by rotating a handle provided on the side of the press machine, is difficult to accurately operate. Automatic setting, which is done by ON/OFF operation of a pushbutton switch on a control box, is also hard to accurately operate.
Control o~ the speed of vertically moving ram in the press machine or bending press is accomplished by opening and closing an unload valve in the hydraulic circuit that drives the ram vertically. The above-mentioned unload valve is opened and closed by stepping on a link-type foot pedal on the Eront of the press machine. This makes it impossible to ' .
operate the press machine Erom a remote location, which is a problem Erom the polnt of view of safety improvement.
There is another type of press machine or bending press in which there is a hydraulic fluid - filled cylinder under the foot pedal, and the pressure on the foot pedal is transmitted through the fluid to operate the unload valve.
However, this method also has problems: the hydraulic hose connected to the foot pedal is large in diameter and rigid, which makes operation difficult; and, when the machine is moved or transported, the foot pedal must be removed from the press machine allowing some of the hydraulic fluid to leak out and get on the floor and other nearby objècts.
Still another problem with existing press machines or bending presses is that there is no detection device to directly detect the position of -the ram which moves vertically.
SUMMARY OF THE INVENTION
This invention was conceived with a view to solving the problems described above.
The first purpose oE this invention is to provide a press machine or bending press in which the stop position o~
the ram in khe vertical movement is determined accurately in a proportional relationship with the up-and-down motion of the ram.
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The second purpose of this invention is to provide a press machine or bending press on which the setting of the position at which the vertically moving ram is stopped can be set easily and accurately.
The third purpose of this invention is to provide a press machine or bending press on which the speed of the vertically moving ram can be easily controlled.
The fourth purpose of this invention is to provide a press machine or bending press on which the position to which the ram has been raised or lowered can be easily detected.
To achieve the first of the objectives listed above, in this press machine or bending press the position ~ determining member which contacts the operation member on the ram to stop the vertical movement of the ram for position determining is adjusted by linear motion.
To achieve the second of the objectives ].isted above, the position determining member is moved by a pulse mo-tor; the control section includes a pulse generator which controls the pulse motor an~ also an indicator which indicates the position oE the position - determining member as judged from how far the pulse motor has actually moved.
To achieve the third of the objectives listed above, an electromagnetic proportional valve is installed in the hydraulic circuit which drives the ram up and down. The ; system is designed so that the speed of the vertically moving ; ram can be controlled by the control of this electromagnetic .~
.
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proportional valve corresponding to operation of a speed control device.
To achieve the fourth of ~he objectives listed above, a ram position detection device which directly detects the position to which the ram has been raised or lowered is installed.
Other and further objects and advantages of the present invention will be apparent from the following description and accompanying drawings which, by way of illustration, show preferred embodiments of the present invention and the principles thereof.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a perspective view of a press machine incorporating this invention.
Figure 2 is an enlargèd cross-sectional view taken along the line II - II in Figure 1.
Figure 3 is a view seen in the direction of the arrows III-III in Figure 2.
Figure 4 is a cross - sectional view taken along the line IV - IV in Figure 3.
Figure 5 is a partly broken and partly cross-sectional view of another embodiment of the presènt invention.
Figure 6 is an enlarged front view of the control panel shown in Figure 1.
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Figure 7 is a block diagram of the pulse motor control system.
Figure ~ is an enlarged cross-sec-tional view taken along the line VIII - VIII in Figure 1.
Figure 9 is a view seen in the direction of the arrows IX - IX in Figure 8.
Figure 10 is an enlarged cross-sectional view taken along the line X - X in Figure 1.
Figure 11 is a partially cut-away side view of the section shown in Figure 10.
Figure 12 is a cross-sectional view taken along the line XII - XII in Figure 11.
Figure 13 is a hydraulic circuit diagram.
DESCRIPTION OF THE PREFERRED_EM80DIMENT
Referring to Figure ]., a press machine or bending press 1 such as a press brake has right and left C-shaped side frames 3R and 3L, upper and lower frames 5 and 7 supported on both sides by the right and ].eft frames 3R and 3L, and a ram 9 installed inside the lower Erame 7 in an opposing relationship with the upper frame 5. An upper bending tool 11 used for bendin~ sheet-~like workpieces W is attached to the bottom of the above~mentioned upper frame 5 so that it can be removed and replaced. A lower bending tool 13 is attached to the top of the ram 9 opposite to the upper bending tool 1]. so that it ~3!356~
can be removed and replaced ~ s will be explained in more detail below, the ram g is driven up and down by a hydraulic cylinder 15 for vertical operation installed inside the lower ~rame 7. The upward movement of the ram 9 pushes the lower bending tool 13 up against the upper bending tool ll, thereby bending the work piece r .. ch is clamped between the upper and lower bending tools ll and 13. That is, in this embodiment, in order to bend the work piece W the ram 9 moves upward, but the applicability of this invention is not limited to this embodiment; this invention can also be applied in a press machine or bending press in which the ram is installed in the upper frames and moves downward to push one bending tool against the other.
Referring to Figures 2 through 4, the hydraulic cylinder 15 which drives the up-and-down movement of the above-mentioned ram 9 is built in to the lower part of the lower frame 7 having front and rear frames 7a and 7b. In this embodiment, an operation member l9 which is attached to the ram 9 operates a position determining device 17 to determine the position at which the upward movement of the ram is stopped. More specifically, the stop position determining device 17 is attached to the lower rear Erame 7b, which is located to the rear of the ram 9, through a bracket 21. The operation member l9 is located so that its tip sticks through the opening of the lower rear frame 7b to within the range of movement of a position determining member 23, which is part of ...
123~3S~i~
the position determining device 17 and is installed so that its position can be adjusted. The system is designed so that the upward movement of the ram 9 will stop when this operation member 19 contacts the position determining member 23.
Consequently, the stop position of the ram 9 in the vertical operation can be controlled by adjusting the position of the stop position determining member 23.
As can be seen from Figures 2 through ~, the position determining member 23 is designed so that its position is adjusted by linear up-and-down motion. That is to say, two opposing guide rails 25 are mounted on the above-mentioned bracket 21i these guide rails 25 support the position determining member 23 while allowing it to move up and down.
The position determining member 23 is screwed into a threaded bolt 27 which is parallel to the guide rails 25; this threaded bolt 27 is coupled to a pulse motor PM which is mounted on the bracket 21. Consequently, by turning the threaded bolt 27 by the pulse motor PM, the position determining member 23 can be moved up and down along the guide rails 25.
In more detail, the pulse motor PM has a pulse encoder PE which detects the actual amount of rotation oE the pulse motor PM; and a rotatincJ shaft 29 oE the pulse motor PM and the lower end of the above-mentioned threaded bolt 27 are spline-coupled. In addition, the upper end o~ the threaded bolt 27 is rotatably supported by a bearing block 31, which is supported so that it is free to move up and down along the _9_ .
~X~38~
above-men-tioned guide rails 25. That is, when the upward motion of the above-mentioned ram 9 pushes the operation member 19 up against the position determining member 23, the position determining member 23 and the threaded bolt 27 can move upward together as a single unit.
In order to detect the contact o~ the operation member 19 with the position determining member 23 and stop the upward motion of the ram 9, the stop position determining device 17 has a switching valve 33 which opens and closes the hydraulic circuit to the above- mentioned hydraulic cylinder 15. This switching valve 33 having a slidable spool 33S allows part of the hydraulic fluid in the above-mentioned hydraulic circuit to return to a tank when the spool 33S is pushed. One end of the spool 33S is in contact with one end 35a of a lever 35.
The lever 35 is connected to the bracket 21 through a shaft 37 so that it is free to swing. The other end 35b oE the lever 35 is in contact with the above-mentioned bearing block 31.
The above-mentioned lever 35b is always held at the other end thereof in contact with the bearing block 31 by the action of an elastic body 39' such as a torsion spring or a compression spring.
As can be understood from the mechanism described above, as mentioned above when the operation member 19 contacts the position determining member 23, the lever 35 is rotated against the resistance of the elastic body 39', and the spool 33S of the switching valve 33 is pushed against one 1238~i~4 end 35a of the lever 35, causing the switching valve 33 to operate, stopping the upward motion of the ram 9.
When the above-mentioned pulse motor PM is operated to raise or lower the above-mentioned position determining member 23, in order to detect whetner or not the position determining member 23 is in contact with the operation member 19, as is most clearly shown in Figure 3, an auxiliary lever 39 is attached to the above-mentioned lever 35 at the center -thereof and extending in an up-down direction. Dogs 41a and 41b are attached to both sides of the tip of this auxiliary lever 39 so that they can be ad~usted. The dog 41a is opposite a first limit switch LSl which is attached to a mounting plate 43 which is fixed to the bracket 21. The other dog 41b is opposite a second limit switch LS2 which is also attached to the mounting plate 43. That is to say, the tip of the auxiliary lever 39 is located between the limit switches LSl and LS2.
In the above configuration, as has already been discussed when the operation member 19 contacts the position determininy member 23, the lever 35 rotates causing the normally closed contact oE the second limit switch LS2 to open; thus the contact oE the operation member 19 with the position determininy member 23 is detected.
When an instruction to the pulse motor PM starts the pulse motor PM rotating in such a direction as to turn the threaded bolt 27 in a direction that drives the position ~2~35~
determining member 23 downward, the position determining member 23 contacts the operation member 19. In addition, when the threaded rod 27 rotates in such a direction as to advance downward, the bearing block 31 rises and the lever 35 rotates pushing the spool 33S of the swtiching valve 33. If the spool 33S of the switching valve 33 is pushed farther than necessary, the first limit switch LS1 switches ON and the rotation commands to the pulse motor Pl~ stop. In this way the rotation of the threaded bolt 27 shows that the position determining member 23 cannot go down any farther.
A third limit switch LS3 is attached to the bracket to detect when the position determining meber 23 has reached its upper limit. A dog 45 is attached to the position determining member 23 so that it can be freely adjusted, in order to operate the third limit switch LS3. Consequently, when the third lirnit switch LS3 has been operated, it is knowrl that the position determining member 23 cannot be moved up any farther.
Figure 5 shows another embodiment in which the threaded bolt 27 operates the switching valve 33 directly. In this embodiment, a driven pulley 49 is rotatably supported by a bearing block 47, which is attached to the switching valve 33.
The upper tip oE the threaded bolt 27 is spline-coupled to this driven pulley ~9. In addition, the threaded bolt 27 i.s connected to the spool 33S oE the switching valve 33 through a sliding pin 51. A belt 53 connects the driven pulley 49 to a driving pulley 55 which is in turn driven by the pulse motor PM.
, ~23~
Since this embodiment operates in a slmilar manner to the embodiment discussed above, like members havin~ similar functions are designated by like numbers, and the detailed explanation is omitted here.
It should be noted that this invention can be used in a number of different embodiments. For example, the position determining member 23 could have a slanted surface which the operation member 19 would contact, and a component of the force would move the position determining member 23.
configuration in which the position determining member 23 is adjusted by horizontal movement is also possible.
Referring again to Figure 1, the press machine 1 has a control panel 57 which controls the press machine 1 and the pulse motor PM. More specifically, a control box 59 is moun-ted on either one of the above-men-tioned right and left side frames 3R and 3L as appropriate. Mounted on this control box 59 is a supporting column 61 which sticks straight up and is free to rotate. This supporting column 61 in turn supports at the upper portion thereof the base of an arm 63 which can be adjusted by expansion and contraction. Rotatably depending from the tip of this arm 63 is a support bar 65, at the lower end of which is supported the control panel 57. Thus, the position of the control panel 57 can be acljustecl arbitrarily throuyh a fairly wide ranye.
As shown in detail in Figure 6, the control panel 57 has a manual pulse generator 67 for operating the ., .
~L~385~4 above-mentioned pulse motor PM and a position indicator 69 which receive~s the pulse signals from the above-mentioned pulse encoder PE and indicates the position of the position determining member 23. The control panel 57 also has an origin setting button 71 which sets as the origin the position to which the ram 9 has risen when the above-mentioned upper bending tool 11 and lower bending tool 13 are in direct contact to generate a predetermined pressure between them, a lower limit position setting switch 73 which can set the lower limit position of the ram 9 to any desired value, and a speed conversion position setting switch 75 which automatically changes the rising speed of the ram 9 at an arbitrarily selected position. The above-mentioned lower limit position setting switch 73 and speed conversion position setting switch 75 are digital switches, and their settings can be changed arbitrarily.
The above-mentioned manual pulse generator 67 might, for example, be a pulse encoder. When a knob 67N is turned, pulses correspondiny to the speed are generated. As shown in Figure 7, this manual pulse generator 67 is connected to a motor driver 77, which drives the above-mentioned pulse motor PM, through a rotation direction discrimination circuit 79.
Connected to the motor driver 77 are an auxiliary switch 81, which overrides input from the manual pulse generator 67, even when rotated, and prevents the pulse motor PM from turning, and the limit switches LSl and I.S3 which detect when the ... .
1~3~3S~
position determining member 23 has reached its moving limits.
Consequently, when the auxiliary switch 81 and the limit switches LSl and LS3 are all closed, turning the knob 67N of the manual pulse generator 67 in the forward or reverse direction causes the pulse motor PM to turn in the forward or reverse direction at a rate corresponding to the speed. In this way the position of the above-mentioned position determining member 23 is adjusted.
The turning of the above-mentioned pulse motor PM is detected by the pulse encoder PE. This pulse encoder PE is connected to a counter 83 which counts the pulses from it.
The value of the count is used by the position indicator 69 to give a digital indication of the position oE the above-mentioned position determining rnember 23. The counter 83 is cleared by the origin switch SW when the origin oE the ram is to be set.
Consequently, by operating the manual pulse generator 67 while watching the position indicator 69, the position of the position determining member 23 can be set accurately, which also means that the position at which the ram 9 will stop rising is determined accurately. Since the actual rotation oE the pulse motor PM during the rotation of pulse motor is detected by the pulse encoder PE, the position oE the position determining member 23 is always indicated accurately even iE a step out problem occurs, for example if the knob 67N
oE the manual pulse generator 67 is turned too fast and the . . .
,~ ,. . . . .
~23~ 4 pulse motor PM can't keep up, or there are large load fluctuations beyond the capability of the pulse motor PM to follow. The pulse motor PM can be operated in either the forward or reverse direction automatically, without using the manual pulse generator 67, by connecting it to another suitable pulse generator.
Referring to Figures 8 and 9, the press machine 1 has a position detecting system 85 to detect the vertical position to which the above-mentioned ram 9 has been raised or lowered.
More specifically, the position detecting system 85 comprises a position detector 87, such as a linear encoder, which is mounted on the lower rear frame 76, and a detection member 89 which is mounted on this position detector 87 so as to be able to move up and down freely. The upper tip of this detection member 89 is coupled to a coupling block 93, which is attached to the ram 9, through a suitable elastic body 91. In this embodiment the elastic body 91 is a plate spring with a 90 twist. A lower limit dog 95 is fixed to the above-mentioned coupling block 93 so that its position can be adjusted up and down ~reely. Mounted on the lower rear Erame 76 is a forth limit switch LS~, which is operated by the lower limit dog 95 when the ram 9 has been lowered to its lower limit position.
In the configuration described above, the detection member 89 and the ram 9, which are coupled, move up and down together, and pulses corresponding to the amount oE vertical motion of the ram 9 are generated by the position detector 87.
1~3~
Conse~uently, by counting the above-mentioned pu].ses, the position to which the ram 9 has been raised or lowered can be detected and the necessary switching performed at the positions set by the lower limi~ position setting switch 73 and the speed conversion position setting switch 75.
When the ram 9, lowering from its raised position, reaches the positlon which has been set by the lower limit position setting switch 73, its lowering movement stops. When the ram 9, rising from its lowered position, reaches the position which has been set by the speed conversion position setting switch 75, the rising speed of the ram 9 is switched Erom fast to slow.
When the ram 9 moves up or down and its position is detected by the above-mentioned position detector 87 as discussed above, if errors occur in the positions o:E the surfaces of -the coupling block 93 connected to the elastic body 91 and to the detector 87, or if the ram 9 is deformed when the workpiece W is bent, the error can be absorved by deformation of the elastic body 91. That is to say, in the configuration described above the position to which the ram 9 is raised or lowered can be detected accurately.
Referring again to Figure 1, the above-mentioned control box 59 is connected to a foot pedal unit 99 through a cable 97. The Eoot pedal unit 99 can be positioned anywhere within a fairly wide range with respect to the above-mentioned control panel 57. The foo-t pedal unit 99 controls the speed 123~5~
of the above-mentioned vertically moving ram 9O It has a pedal 101U for upward movement and a pedal 101L for downward movement.
As is shown best in Figures 10 through 12, the ~oot pedal unit 99 is contained in a box 105 which has an opening 103 on one side for inserting toes. This box 105 is made in one piece with a casing 109 which has a handle 107 on the top thereoE. Inside this casing 109 are a pair of vertically moving rods 113U and 113L supported by a side bracket 111, inside the box 105, so that they can move up and down freely, and in addition a potentiometer 115 is mounted in a vertical position.
A disc-shaped stop member 117 is integrally mounted to an operation rod 115R of the above-mentioned potentiometer 115. The operation rod 115R is always pushed upward by the action of a spring 119 compressed between this stop member 117 and the bracket 111. Operation pieces 121U and 121L, which are ~ree to contact the upper surface of the above-mentioned stop member 117, are attached to the above-mentioned vertically moving rods 113U and 113L. In addition, these vertically moving rods 113U and 113L are always biased upward by the action of springs 123U and 123L.
The diameters of the vertically moving rods 113U and 1131, are reduced at their lower tips. Limit switches LSU and LSL are mounted in positions corresponding to these narrowed tips. In addition, rollers 125U and 125L are attached to the
3~35~
lower tips of the vertically movin~ rods 113U and 113L.
Levers 127U and 127L, which are connected to the above-mentioned pedals lOlU and lOlL, are in contact with the tops of the rollers 125U and 125L. The pedals lOlU and lOlL
are pivotally attached to the inside of the bo~ 105 through a shaft 129 which is rotatably supported by the bracket which is connected to the lower frame of the above-mentioned box 105.
In addition, a cover member 133, which has an opening and closing lever 131, is attached to the opening 103 of the box 105 so that it is free to open and close through a shaft 135, which is rotatably supported by the upper frame body of the box 105.
As has already become clear, in the configuration described above when the pedal lOlU for upward movement or the pedal lOlL for downward movement is stepped on, one of the vertically moving rods 113U, 131L is lowered and the corresponding limit switch LSU or LSL operates, and, at the same time, the operation rod 115R of the potentiometer 115 is lowered. Thus, the action of the limit switch LSU or LSL
tells whether the ram 9 is being raised or lowered, while an output signal corresponding to the amount oE motion of the operation rod 115R is obtained from the potentiometer 115. By controlling an electro- magnetic proportional valve to be described later, corresponding to the output signal from this potentiometer 115, the rising or lowering speed oE the ram 9 is controlled corresponding to the amount of foot pressure on ~ --1 9--~' ~3~5~
the pedal 101U or 101L.
Referring to Figure 13, a 4-port 3-position solenoid valve 137 is connected to a Eirst hydraulic fluid path Ll which in turn is connected to a hydraulic pump P. At the same time a relief valve 139 and an electromagnetic valve 141 are branch-connected. The electromagnetic proportional valve 141 is supposed to control the flow rate of hydraulic fluid which is recirculated to the tank T in either direct or inverse proportion to the voltage applied to a solenoid SOL.
The above-mentioned solenoid SOL o~ the electromagnetic proportional valve 141 is controlled by a controller 143. The controller 143 receives input feed back signals for position detection of the spool of the electromagnetic proportional valve 141. The con-troller 143 is also connected to the above-mentioned potentiometer 115 and to the above-mentioned limit swltches LSU and LSL. Consequently the controller 143 can receive signals from the limit switches LS~ and LSL and judge the directionality, and control the degree of opening oE the electrornagnetic proportional valve 141 corresponding to the output signal from the potentiometer 115.
The above-mentioned solenoid valve 137 is connected to a second hydraulic fluid path L2 which in turn is connected to a first chamber 15F of the above-mentioned cylinder 15 used for the vertical movement of the ram. This second hydraulic fluid path L2 is provided with a check valve 145 and a counterbalance valve 147 in parallel. In addition the 3L2~5j~
above-mentioned switchiny valve 33 is connected to a branch of the hydraulic system.
In addition, a third hydraulic fluid path L3 is connected a~ a branch of the second hydraulic fluid path. A
speed conversion valve 149 is installed in this third hydraulic fluid path L3. A regulator 151 is branch-connected to the above-mentioned third hydraulic fluid path L3; and a manometer 153 is also branch-connected through a cutoff valve 155.
A forth hydraulic fluid path L4, which is connected to the above-mentioned speed switching valve 1~9, is connected to a second chamber 15S of the hydraulic cylinder 15, and to an auxiliary cylinder 157; and, at the same time, it is connected to the tank T through a check valve 159 and a pilot - operated check valve 1610 In addition, a fifth hydraulic path L5, which is connected to the above-mentioned solenoid valve 137, is connected to a third chamber 15T of the hydraulic cylinder 15.
In the configuration described above, stepping on the pedal lOlU for upward movement o~ the foot pedal unit 99 cuts off the connection to the electromagnetic proportional valve 1~1; in addition, when the solenoid valve 137 is switched to connect the Eirst hydraulic fluid path Ll to the second hydraulic fluid path L2, hydraulic Eluid is supplied from the hydraulic f:luid pump P to the first chamber 15F of the hydraulic cylinder 15, driving the ram 9 upward. At this time ~IL2385~
the rising speed of the ram 9 can be controlled by controlling the degree of opening of the electromagnetic proportional valve 141, which is done by adjusting the foot pressure on the pedal lOlU in the foot pedal unit 99.
When the ram 9 is driven upward as described above, the position to which the ram 9 has risen is detected by the position detector 87. When the ram 9 rises to the position which has been set in advance by the speed conversion position setting switch 75, the speed switching valve 149 is operated, hydraulic fluid is also supplied to the second chamber 15S of the cylinder 15 and to the auxiliary cylinder 157, and the rising speed of the ram 9 is switched ~rom fast to slow; and the workpiece W between the upper bending tool 11 and the lower bending tool 13 is bent.
When, as discussed above, the ram 9 is raised, and, as also discussed above, the operation member 19 attached to the ram 9 contacts the position determining member 23, the switching valve 33 switches and part of the hydraulic fluid drains back to the tank T, so the rising oE the ram 9 stops.
After that, when the solenoid valve 137 switches, hydraulic Eluid is supplied to the third chamber 15T oE the cylinder 15, and, at the same time, the pilot operated check valve 161. is opened causing the ram 9 to be lowered. At this time, the speed oE lowering oE the ram 9 can be controlled by adjusting the foot pressure on the pedal lOlL in the foot pedal unit 99.
When the ram 9 is lowered as discussed above, and the . -22-~Z3~5~4 position of the ram 9 as detected by the position detector 87 reaches the position which has been set in advance by the lower limit position setting switch 73, the lowering of the ram 9 stops.
As can be understood from the explanation above, the positions where the rising and lowering of a ram in a press machine stop can be set accurately. In addition, the speed of the vertically moving ram can be controlled accurately, and the position of the ram can be accurately detected.
While preferred embodiments of this invention have been shown and described, it will be appreciated that other embodiments will become apparent to those skilled in the art upon be limited by the disclosed embodiments.
::. ...
lower tips of the vertically movin~ rods 113U and 113L.
Levers 127U and 127L, which are connected to the above-mentioned pedals lOlU and lOlL, are in contact with the tops of the rollers 125U and 125L. The pedals lOlU and lOlL
are pivotally attached to the inside of the bo~ 105 through a shaft 129 which is rotatably supported by the bracket which is connected to the lower frame of the above-mentioned box 105.
In addition, a cover member 133, which has an opening and closing lever 131, is attached to the opening 103 of the box 105 so that it is free to open and close through a shaft 135, which is rotatably supported by the upper frame body of the box 105.
As has already become clear, in the configuration described above when the pedal lOlU for upward movement or the pedal lOlL for downward movement is stepped on, one of the vertically moving rods 113U, 131L is lowered and the corresponding limit switch LSU or LSL operates, and, at the same time, the operation rod 115R of the potentiometer 115 is lowered. Thus, the action of the limit switch LSU or LSL
tells whether the ram 9 is being raised or lowered, while an output signal corresponding to the amount oE motion of the operation rod 115R is obtained from the potentiometer 115. By controlling an electro- magnetic proportional valve to be described later, corresponding to the output signal from this potentiometer 115, the rising or lowering speed oE the ram 9 is controlled corresponding to the amount of foot pressure on ~ --1 9--~' ~3~5~
the pedal 101U or 101L.
Referring to Figure 13, a 4-port 3-position solenoid valve 137 is connected to a Eirst hydraulic fluid path Ll which in turn is connected to a hydraulic pump P. At the same time a relief valve 139 and an electromagnetic valve 141 are branch-connected. The electromagnetic proportional valve 141 is supposed to control the flow rate of hydraulic fluid which is recirculated to the tank T in either direct or inverse proportion to the voltage applied to a solenoid SOL.
The above-mentioned solenoid SOL o~ the electromagnetic proportional valve 141 is controlled by a controller 143. The controller 143 receives input feed back signals for position detection of the spool of the electromagnetic proportional valve 141. The con-troller 143 is also connected to the above-mentioned potentiometer 115 and to the above-mentioned limit swltches LSU and LSL. Consequently the controller 143 can receive signals from the limit switches LS~ and LSL and judge the directionality, and control the degree of opening oE the electrornagnetic proportional valve 141 corresponding to the output signal from the potentiometer 115.
The above-mentioned solenoid valve 137 is connected to a second hydraulic fluid path L2 which in turn is connected to a first chamber 15F of the above-mentioned cylinder 15 used for the vertical movement of the ram. This second hydraulic fluid path L2 is provided with a check valve 145 and a counterbalance valve 147 in parallel. In addition the 3L2~5j~
above-mentioned switchiny valve 33 is connected to a branch of the hydraulic system.
In addition, a third hydraulic fluid path L3 is connected a~ a branch of the second hydraulic fluid path. A
speed conversion valve 149 is installed in this third hydraulic fluid path L3. A regulator 151 is branch-connected to the above-mentioned third hydraulic fluid path L3; and a manometer 153 is also branch-connected through a cutoff valve 155.
A forth hydraulic fluid path L4, which is connected to the above-mentioned speed switching valve 1~9, is connected to a second chamber 15S of the hydraulic cylinder 15, and to an auxiliary cylinder 157; and, at the same time, it is connected to the tank T through a check valve 159 and a pilot - operated check valve 1610 In addition, a fifth hydraulic path L5, which is connected to the above-mentioned solenoid valve 137, is connected to a third chamber 15T of the hydraulic cylinder 15.
In the configuration described above, stepping on the pedal lOlU for upward movement o~ the foot pedal unit 99 cuts off the connection to the electromagnetic proportional valve 1~1; in addition, when the solenoid valve 137 is switched to connect the Eirst hydraulic fluid path Ll to the second hydraulic fluid path L2, hydraulic Eluid is supplied from the hydraulic f:luid pump P to the first chamber 15F of the hydraulic cylinder 15, driving the ram 9 upward. At this time ~IL2385~
the rising speed of the ram 9 can be controlled by controlling the degree of opening of the electromagnetic proportional valve 141, which is done by adjusting the foot pressure on the pedal lOlU in the foot pedal unit 99.
When the ram 9 is driven upward as described above, the position to which the ram 9 has risen is detected by the position detector 87. When the ram 9 rises to the position which has been set in advance by the speed conversion position setting switch 75, the speed switching valve 149 is operated, hydraulic fluid is also supplied to the second chamber 15S of the cylinder 15 and to the auxiliary cylinder 157, and the rising speed of the ram 9 is switched ~rom fast to slow; and the workpiece W between the upper bending tool 11 and the lower bending tool 13 is bent.
When, as discussed above, the ram 9 is raised, and, as also discussed above, the operation member 19 attached to the ram 9 contacts the position determining member 23, the switching valve 33 switches and part of the hydraulic fluid drains back to the tank T, so the rising oE the ram 9 stops.
After that, when the solenoid valve 137 switches, hydraulic Eluid is supplied to the third chamber 15T oE the cylinder 15, and, at the same time, the pilot operated check valve 161. is opened causing the ram 9 to be lowered. At this time, the speed oE lowering oE the ram 9 can be controlled by adjusting the foot pressure on the pedal lOlL in the foot pedal unit 99.
When the ram 9 is lowered as discussed above, and the . -22-~Z3~5~4 position of the ram 9 as detected by the position detector 87 reaches the position which has been set in advance by the lower limit position setting switch 73, the lowering of the ram 9 stops.
As can be understood from the explanation above, the positions where the rising and lowering of a ram in a press machine stop can be set accurately. In addition, the speed of the vertically moving ram can be controlled accurately, and the position of the ram can be accurately detected.
While preferred embodiments of this invention have been shown and described, it will be appreciated that other embodiments will become apparent to those skilled in the art upon be limited by the disclosed embodiments.
::. ...
Claims (11)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A press machine comprising:
a generally vertically movable ram for support-ing an upper or lower bending tool, said ram having an operation member affixed thereto;
a position determining member for determining an upper limit position of the ram which supports the lower bending tool, or for determining a lower limit position of said ram, said position determining member locatable at a suitable point so that when the operation member on the ram contacts the position determining member a control function can be initiated to stop the vertical movement of the ram; and an operation mechanism for adjusting the position of this position determining member along a straight line path;
whereby the stop position of the ram can be controlled by adjusting the location of the position determining member along said path.
a generally vertically movable ram for support-ing an upper or lower bending tool, said ram having an operation member affixed thereto;
a position determining member for determining an upper limit position of the ram which supports the lower bending tool, or for determining a lower limit position of said ram, said position determining member locatable at a suitable point so that when the operation member on the ram contacts the position determining member a control function can be initiated to stop the vertical movement of the ram; and an operation mechanism for adjusting the position of this position determining member along a straight line path;
whereby the stop position of the ram can be controlled by adjusting the location of the position determining member along said path.
2. The press machine as described in claim 1, wherein the position of the position determining member is adjustable in the same direction as the vertical movement of the ram.
3. The press machine according to claim 2, further comprising a frame, wherein the operation mechanism which determines the position of the position determining member is a screw mechanism including:
a threaded rod which is mounted on the frame slidably in the axial direction thereof and is screw-coupled to the psoition determining member; and a drive unit for rotating the threaded rod to effect movement of the positioning determining member along the straight line path; and a coupling member for coupling the threaded rod with the drive unit in a manner that the threaded rod is slidable in the axial direction thereof, against the drive unit.
a threaded rod which is mounted on the frame slidably in the axial direction thereof and is screw-coupled to the psoition determining member; and a drive unit for rotating the threaded rod to effect movement of the positioning determining member along the straight line path; and a coupling member for coupling the threaded rod with the drive unit in a manner that the threaded rod is slidable in the axial direction thereof, against the drive unit.
4. The press machine as described in claim 3, wherein the drive unit which rotates the threaded rod is a pulse motor and a manual pulse generator being provided to operate the pulse motor from a remote location.
5. The press machine as described in claim 4, including a control section, which includes the manual pulse generator, and which also includes a position indicator which indicates the position of the position determining member based on the actual amount of rotation of the pulse motor.
6. A press machine according to claim 1, further comprising a hydraulic circuit for driving the vertically movable ram up and down; and electromagnetic proportional valve installed in the hydraulic circuit and controlling the speed of vertical movement of said ram; a speed control device for controlling the electromagnetic proportional valve adjustably located at any desired position; wherein the speed of vertical movement of said ram can be controlled in correspondence with the control setting of said speed control device.
7. The press machine as described in claim 6, wherein said speed control device is a foot pedal unit which has one pedal for upward movement and another pedal for downward movement; and a signal generating device is provided to generate signals corresponding to the amount of foot pressure on said pedals.
8. The press machine according to claim 1, further comprising:
a frame;
vertical position detector for detecting vertical positions of the ram;
said vertical position detector having a position detection rod member coupled to said ram through the elastic body which is flexible in directions perpen-dicular to the moving direction of the ram; and detecting device mounted on the frame, to detect a moving direction and a moving length of the ram, said detecting device engaging with the position detection rod member so that the position detection rod member is slidable in the axial direction thereof, against the detecting device.
a frame;
vertical position detector for detecting vertical positions of the ram;
said vertical position detector having a position detection rod member coupled to said ram through the elastic body which is flexible in directions perpen-dicular to the moving direction of the ram; and detecting device mounted on the frame, to detect a moving direction and a moving length of the ram, said detecting device engaging with the position detection rod member so that the position detection rod member is slidable in the axial direction thereof, against the detecting device.
9. The press machine as described in claim 8, wherein said elastic body is a plate spring with a 90° twist.
10. A press machine, comprising:
a frame;
a ram connected to and movable with respect to the frame, said ram supporting bending tools;
means for detecting movement of the ram, said means including an operation member mounted on the ram, and a position determining member mounted on the frame in an adjustable position such that when the ram moves a desired amount the operation member contacts and causes movement of the position determining member;
hydraulic switch means mounted on the frame for controlling movement of the ram;
lever means mounted on the frame and interconnecting the position determining member with the hydraulic switch means such that the movement of the position determining member controls the hydraulic switch means.
a frame;
a ram connected to and movable with respect to the frame, said ram supporting bending tools;
means for detecting movement of the ram, said means including an operation member mounted on the ram, and a position determining member mounted on the frame in an adjustable position such that when the ram moves a desired amount the operation member contacts and causes movement of the position determining member;
hydraulic switch means mounted on the frame for controlling movement of the ram;
lever means mounted on the frame and interconnecting the position determining member with the hydraulic switch means such that the movement of the position determining member controls the hydraulic switch means.
11. A press machine, comprising:
a frame;
a ram connected to and movable with respect to the frame, said ram supporting bending tools;
an operation member mounted on the ram;
a position determining member mounted for vertically adjustable movement on the frame on a pair of vertically disposed guide rails mounted on the frame such that when the ram moves a desired amount the operation member contacts and causes movement of the positioning determining member;
switch means operatively connected to the position determining member for controlling movement of the ram such that said movement of the position determining member controls the switch means;
means for adjusting the position of the position determining means;
control means for controlling the position adjusting means, said control means including means for setting the position determining means within preferred limits.
a frame;
a ram connected to and movable with respect to the frame, said ram supporting bending tools;
an operation member mounted on the ram;
a position determining member mounted for vertically adjustable movement on the frame on a pair of vertically disposed guide rails mounted on the frame such that when the ram moves a desired amount the operation member contacts and causes movement of the positioning determining member;
switch means operatively connected to the position determining member for controlling movement of the ram such that said movement of the position determining member controls the switch means;
means for adjusting the position of the position determining means;
control means for controlling the position adjusting means, said control means including means for setting the position determining means within preferred limits.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000557099A CA1256363A (en) | 1983-08-24 | 1988-01-21 | Press machine |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP12975583U JPS6038619U (en) | 1983-08-24 | 1983-08-24 | Mobile positioning device |
| JP58-129755 | 1983-08-24 |
Related Child Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000557099A Division CA1256363A (en) | 1983-08-24 | 1988-01-21 | Press machine |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1238564A true CA1238564A (en) | 1988-06-28 |
Family
ID=15017390
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000461503A Expired CA1238564A (en) | 1983-08-24 | 1984-08-22 | Press machine |
Country Status (2)
| Country | Link |
|---|---|
| JP (1) | JPS6038619U (en) |
| CA (1) | CA1238564A (en) |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5335031A (en) * | 1976-09-13 | 1978-04-01 | Teijin Ltd | Automatic doffing device |
| JPS54129573A (en) * | 1978-03-31 | 1979-10-08 | Amada Co Ltd | Stroke controller in bending machine |
-
1983
- 1983-08-24 JP JP12975583U patent/JPS6038619U/en active Pending
-
1984
- 1984-08-22 CA CA000461503A patent/CA1238564A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6038619U (en) | 1985-03-18 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |