JPS5950480B2 - Operating mechanism for hollow punching machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an operating mechanism for a hollow puncher, and more particularly to a cantilevered hollow puncher.

The mechanism of the invention is particularly suitable for hollow punching machines used in the boot and shoe manufacturing industry, but can be used in any other cantilever type hollow punching machine.

As is well known, cantilever hollow punching machines have operating mechanisms for cutting the material being machined.

The operating mechanism mainly consists of a hydraulic circuit in which the pressure fluid discharged from the pump circulates, and the hydraulic circuit is equipped with a valve, which has a valve spool and a fluid suction duct formed in the valve body by cutting. The duct communicates with the first and second chambers of the cylinder to move the moving part of the cylinder up and down.

Additionally, the operating mechanism includes an electrical circuit that is manually controlled by the operator to adjust the valve spool to open one of the outlet passages or the other to the first or second chamber of the cylinder. The inflow of fluid into the outlet passage can be regulated.

One of the problems with the known type of mechanism is that the rate of descent of the moving part of the cylinder, ie the rate of descent of the head, is much faster than the rate of rise of this moving part.

The slow rate of rise of the moving parts of the cylinder causes an increase in manufacturing time and has a negative impact on the cost of the manufactured product. A second problem with operating mechanisms of the type described above is that immediately after the completion of the upward return stroke of the moving part of the cylinder, the valve spool
The passages leading to the corresponding chambers of the cylinders are closed almost simultaneously, so that the moving parts stop almost simultaneously.

This is obviously the cause of vibrations in the moving parts of the cylinder,
In other words, it causes vibrations in the machine head. As a result, the physical properties of the oil deteriorate, requiring frequent oil changes. The next problem experienced with conventional types of mechanisms is that in order to match the cutting depth of the punch used,
This stems from the inability to properly and quickly adjust the height of the table on the hollow punching machine.

Typically, a screw-type mechanism is used for this adjustment, and the operator manually turns the screw using a steering wheel. This is obviously time for adjustment.
At the same time, a second adjustment device is required that can further achieve the desired depth accuracy. ' Another problem is that
Since the head of a hollow punching machine generally tends to flex to some extent due to its weight, so that the cutting depth in the front part of this machine is greater than that in the rear part, it is necessary to provide an operating mechanism of known type. The problem with hollow punching machines is that the precision of punching is lacking.

A potentiometer is placed in the electric circuit belonging to the operating mechanism, and immediately after the punching operation is completed, a delay in return is given to the head,
It is known that the aforementioned problems have been partially overcome by giving the head more time to complete the punching operation.

As is well known, the potentiometer must be set by the operator each time there is a change in the thickness of the material being punched.

The delay in the return of the head after the punching operation is completed is necessary to ensure that the leather sheet under the punching tool is cut, and to prevent machine vibrations and protect the machine.

In other words, if the head returns immediately after the punching is completed, the leather sheet under the punching tool will not be cut properly, and if the leather sheet is thick, it will not be possible to cut it, and due to the difference in sheet thickness. It is necessary to change the delay in the return of the head. Furthermore, if the head were to rise immediately after punching is completed, the head itself would recoil, causing the machine to vibrate or the motor to overheat, potentially causing a breakdown. The aim of the invention is to eliminate all the problems as mentioned above, by means of an operating mechanism which provides, inter alia:

(a) Same raising and lowering speed for the head.

(b) Once the head of the hollow punch has returned to its upper position, it should gradually stop. (c) automatically and accurately adjusting the height of the table prior to the punching operation; (d) To enable a dynamic delay by simply pressing one of the push buttons provided by the hollow puncher.

The subject of the invention is particularly for a hollow punching machine, comprising a hydraulic circuit for operating a cylinder connected to the head of the hollow punching machine, said hydraulic circuit comprising a valve slid into a valve body. A valve having a spool with two passages communicating with a first chamber in the cylinder for raising the moving part of the cylinder and a second chamber for lowering the moving part of the cylinder. the valve spool is provided with a valve capable of bringing the fluid absorption duct into communication, said valve spool being operable for a hollow punching machine, in particular for a cantilever type hollow punching machine, controlled by an electric circuit. The valve spool 7 and the valve body 6 are arranged between their relative sliding surfaces to move the suction data 8 into the first position in the cylinder when the moving part of the cylinder is stopped. The passage 9 communicating with the chamber 31 is communicated through a port portion, and the first exhaust port 11 connected to the first chamber 31 is closed, and the suction duct 8 is connected to the second chamber in the cylinder. means for communicating through a port with said passageway 10 leading to said second chamber 32 and a second discharge port 12 connected to said second chamber 32; The suction duct 8 is connected to the passage 10 communicating with the second chamber 32, and the second discharge duct 12 is closed, and the means for closing the passage 9 with respect to said suction duct 8; when the moving part of said cylinder is raised, corresponding to the return of the head of said hollow puncher after completion of the punching operation; The passage 9 that communicates the duct 8 with the first chamber 31 and the second chamber 32
and 10, and means for simultaneously closing both the first discharge duct 1 and the second discharge duct 12; the moving part of the cylinder is still raised, but at the end of its stroke; The suction duct 8 is connected to the passage 9 communicating with the first chamber 31 in the cylinder, and the first discharge duct 1
1, and further the passage closed with respect to the suction duct 8 leading to the second chamber 32]0, the second
means for communicating the discharge port 12 through the constriction, the valve spool 7 having means controlled by said electrical circuit for moving said valve spool 7 in a direction corresponding to the lowering of said cylinder. and when the means controlled by said electric circuit ceases to operate. comprising means for constantly biasing the valve spool in the opposite direction, and means for connecting the valve spool and the head in order to gradually stop the movement of the valve spool when the head returns after completion of the punching operation, Furthermore, said electrical circuit comprises automatic delay means for delaying the start of the lifting of the head 5 of the hollow punch, said automatic delay means being capable of selecting a delay time prior to the start of operation of the hollow punch. This is an operating mechanism for a hollow punching machine.

BRIEF DESCRIPTION OF THE DRAWINGS The characteristics of the invention will become clearer from the following description of exemplary embodiments with reference to the accompanying drawings. attached drawings,
In particular, FIG. 5 shows a cantilevered hollow punching machine having a base 1 with a table 2 on which the material to be punched is placed.

The hollow punching machine further has an upright body 3 in which a column 4 slides.

The column 4 is integral with the head of the hollow puncher, designated generally as 5. The operating mechanism of the hollow puncher described above essentially consists of a hydraulic circuit, of which only a portion is shown, since it is of a known type.

The hydraulic circuit consists of a duct connected to a pump that sucks fluid from a tank containing the supply fluid for the hydraulic circuit. Said duct is connected to a valve constituted by a valve body 6 and a valve spool 7 sliding inside the valve body 6. The valve body 6 is integral with the stand 1 of the hollow puncher, while the valve spool 7 is connected to the head 5 of the hollow puncher, as will be explained later. A hydraulic circuit is provided in particular for operating a cylinder connected to the head 5 of the hollow puncher, in which a valve spool 7 communicates a fluid suction duct 8 with a passage 9 leading to a first chamber in the cylinder. When I urge you,
Raise the moving part of the cylinder.

Also, by communicating the fluid suction duct 8 with the second passage 10, the moving part of the cylinder is lowered. The valve spool 7 and the valve body 6 allow the suction duct 8 to communicate through the port portion with a passage 9 leading to a first chamber in the cylinder whenever the moving parts of the cylinder are stationary, and are connected to the first chamber. The first discharge duct 11 is closed, and the suction duct 8
is the second chamber in the cylinder. (- = Passage 10 and 2nd
It has means for communicating through the port with a second exhaust duct 12 connected to the chamber. The state of FIG. 1 corresponds to a stationary stage of the head of the hollow punching machine, in particular a stopped stage when no punching operation is taking place.

The means for bringing the suction duct 8 into communication with the passage 9 leading to the first chamber through the port and for closing the first discharge duct 11 include a substantially annular first projection 13 provided on the valve spool 7; , and a second similarly substantially annular projection 14 located inside the valve body 6 at the point where the passage 9 opens into the first chamber. The height difference between projections 13 and 14 is sufficiently different to allow forced circulation of fluid. The first protrusion 13 has two portions 13a and 13b each having a different diameter. Part 13
The diameter of a is approximately equal to the inner diameter of the second protrusion 14, while the diameter of the portion 13b is smaller than the inner diameter of the second protrusion 14.
When the moving parts of the cylinder are at rest (Fig. 1),
The portion 13b is positioned adjacent to the second protrusion 14,
This forms the port portion described above.

A third substantially annular projection 15 disposed on the valve spool 7 engages a first pair of projections 16 on the valve body 6 at a height corresponding to the entry point of the first discharge duct 11; 1 Close the discharge duct 11.

The first pair'' of projections 16 are generally ring-shaped and their thickness is less than the thickness of the third projection 15. 1, the suction duct 8 is connected to the passage 10 leading to the second chamber and the second discharge when the moving parts of the cylinder are stationary. The means for communicating with the duct 12 through the port portion is provided by a substantially ring-shaped fourth projection 17 disposed on the valve spool 7 and a similarly substantially ring-shaped fifth projection 18 on the valve body 6. It's summery.

The height difference between the projections 17 and 18 is sufficient to allow forced circulation of fluid between the passage 10 leading to the second chamber and the suction duct 8, thereby making it possible to avoid the above-mentioned difference in height. It forms a port section. 7 In particular, the fourth projection 17 decreases in thickness towards the outside and, corresponding to its contour, its thickness is smaller than the thickness of the fifth projection 18.

Finally, the further projections mentioned with respect to FIG.
It can be seen that the passages 10 leading to the second chamber communicate with the second discharge duct 12, since they differ from each other at various heights.

With particular reference to FIG. 2, here the valve consisting of the valve body 6 and the valve spool 7 is moved into the punching stage in response to the downward stroke of the moving part of the cylinder integral with the head of the hollow punching machine. in a position related to

Referring to this figure, the operating mechanism causes the suction duct 8 to communicate with a passage 10 communicating with the second chamber, closes the second exhaust duct 12, and connects the suction duct 8 with a passage 10 communicating with the first chamber, which communicates with the first exhaust duct. It is understood that the suction duct has means for closing with respect to the suction duct.

In particular, the aforementioned means for communicating the suction duct 8 with the passage 10 leading to the second chamber include a fourth protrusion 17 having a height difference sufficient to permit forced circulation of the fluid.
and a fifth protrusion 18.

Projections 17 and 1 when the moving part of the cylinder is lowered
It is understood that the height discrepancy with respect to 8 is greater than in the stationary case when the moving part of the cylinder corresponds to the stationary phase of the head of the hollow punch. The means for closing the second discharge duct 12 and the passage 9 leading to the first chamber with respect to the suction duct 8 are provided by a second pair of projections on the valve body 6 corresponding to the point of entry of the second discharge duct 12. 20 and the second
Close the discharge door 12.

The means consist of a substantially ring-shaped sixth projection 19 on the valve spool 7, and by the first projection 13 and the second projection 14 touching each other at a point corresponding to the part 13a of the first projection 13. is also configured. The diameter of the portion 13a is approximately equal to the inner diameter of the second protrusion 14. It can also be seen that the third projection 15 is remote from one of the two projections 16, in particular the upper one in FIG. Each protrusion 20 of the second pair is substantially ring-shaped and has a thickness much thinner than the thickness of the sixth protrusion 19. The second pair of projections 20 are separated by a distance less than the thickness of the sixth projection 19 such that the sixth projection] 9 is always engaged with at least one of the projections 20. With particular reference to FIG. 3, the valve spool 7 and the valve body 6 are shown in a position relative to the raising phase of the moving part of the cylinder, and therefore of the head, immediately after the completion of the punching operation.

This condition continues for most of the upward movement, and at the end of this upward movement there is a transition to a further condition illustrated in FIG. With reference to FIG. 3, the operating mechanism that is the subject of the invention, when the moving part of the cylinder is raised, connects the suction duct 8 to the passage 9 leading to the first chamber in the cylinder and to the second chamber in the cylinder. It has means for simultaneously communicating with a passageway 10 leading to the chamber, and means for simultaneously closing both the first discharge duct 11 and the second discharge duct 12.

In particular, the means for simultaneously communicating the suction duct 8 with the passages 9 and 10 are constituted by a fourth projection 17 and a fifth projection 18 which are interdigitated with each other.

Compared to the position shown in FIG. 2 when the moving part of the cylinder is in a descending step, the fourth projection 17 is in a substantially symmetrical position with respect to the fifth projection 18. The aforementioned means also consist of a first projection 13 and a second projection 14 which are offset to a greater degree than when the moving parts of the cylinder are at rest, as illustrated in FIG. Referring again to FIG. 3, the means for simultaneously closing the first discharge duct 11 and the second discharge duct 12 when the moving part of the cylinder is rising is in contact with the first pair of projections 16. a third projection 15 in contact with one of the projections of the second pair, and a sixth projection 19 in contact with one of the projections of the second pair; It is understood that it is in contact with the protrusion 21. The seventh projection 21 is dislocated with respect to the other projection 20 of the second pair when the moving part of the cylinder is at rest (FIG. 1) or when it is lowered (FIG. 2). The actual gap width is smaller in the former case than in the latter case. It can also be understood that the seventh protrusion 21 has two portions 21a and 21b with different diameters. The diameter of the portion 21a is
equal to the inner diameter of the other protrusion 20 of the second pair, while
Referring to FIG. 4, the diameter of the portion 21b is smaller than the inner diameter of the other protrusion 20, and there it is located at a position corresponding to the rise of the moving part of the cylinder, but approaching its upper limit. A valve body 6 and a valve spool 7 are shown.

With reference to this figure, the mechanism forming the subject of the invention comprises means for bringing the suction duct 8 into communication with a passage 9 leading to a first chamber in the cylinder and for closing the first discharge duct 11. is understood.

It is understood that the mechanism in question also comprises means for closing the second exhaust duct with respect to the suction duct 8 and communicating it through the port with a passage 10 leading to the second chamber. The means for communicating the suction duct 8 with the passage 9 leading to the first chamber and for closing the first discharge duct consist of a first projection 13 and a second projection 14, which are connected to the cylinder. If the moving part is at rest (
If the distance is greater than that in Figure 1) and the Z is rising (
(Fig. 3), they differ from each other by a smaller distance.

Said means also consist of a third projection 15 contacting the first pair of projections 16. 2nd discharge duct 1
2 is communicated through the port portion with the passage 110 leading to the second chamber by means of a sixth protrusion 19 separated from one of the protrusions of the second pair, and the other of the protrusions of the second pair of protrusions 20. It consists of protrusions 21 which permit forced circulation of the fluid by differing in terms of the angle.

In particular, the seventh protrusion 21. A portion 21b having a smaller diameter than the diameter of This allows for a cycle of Fourth
Since the projection 17 and the fifth projection 18 are in contact with each other, the passage 10 leading to the second chamber is closed with respect to the suction duct 8 . Referring to FIGS. 1 to 5, the valve spool 7 has a valve stem 22 on its upper part, and a return spring 23 is fitted into this valve stem, and the bottom of this spring is held by the valve body 6. , it can be seen that the upper part is held by a tightening nut 24.

The valve spool 7 is connected in a known manner to an electromagnet (not shown) which controls its movement. A valve spool 7 is connected to the head of the hollow punching machine, and for this purpose this valve spool 7 is integral with the end of the connecting cable 25. The cable 25 connects pulleys 26 and 27 rotatably mounted at the same height on the platform 1 of the hollow punching machine, and a pulley 2 rotating at a point corresponding to its upper limit in the column 4.
8 and is wound around a pulley 29 rotatably mounted on the head 5 of the hollow punching machine. The pulley 29 is equipped with an operating handle 30. With particular reference to FIGS. 5 and 6, the cylinder integral with the head 5 of the hollow puncher and the first and second chambers within the cylinder will be described.

The moving part of the cylinder consists of a column 4 of the hollow punch which slides inside the upright 3 of the hollow punch. The column 4 has at its lowermost end a leak-tight member or cover 50 that slides relative to a piston that is integral with the stand 1 of the hollow punching machine.

Inside the piston 37, a first duct 9a (the connection is not shown) connected to the passage 9 in the valve body 6;
There is a second duct 10a (the connection is not shown) connected to the passage 10 within the valve body 6.

The first duct 9a opens into a first chamber 31 within the cylinder, while the duct 10a opens into a second chamber 32 within the cylinder. A first chamber in the cylinder is formed between the upper wall 33 of the larger diameter part of the piston 37, the inner wall of the column 4, which is hollow for this purpose, and the inner side of the column 4 at an intermediate point. It is formed by a leakage prevention member 34 fixed to. The leakage prevention member 34 has a substantially disk shape, and is screwed to the inside of the column 4 with a headless screw 35. The second chamber 32 in the cylinder is formed by the upper wall of the leak-tight member or cover 50, the inner wall of the column 4, and the lower wall 3 of the larger diameter portion of the piston 37.
6 and the outer wall of the portion of the piston 37 where the diameter is smaller. Cylinder first chamber 3
1 has a pressure receiving area that is approximately twice the area of the second chamber.

This means that the area in question consists of the substantially circular lower wall of the leak-tight member 34 and the upper wall of the leak-tight member or cover 50 whose area is substantially between two concentric circles. This is achieved by using facts.
The ratio is therefore approximately 2:1. It will be understood that inside said piston 37 a duct is provided, through which the cable 25 slides inside the piston 37.

It has a damper which acts in cooperation with the valve spool 7 when the moving part of the cylinder is lowered. The damper consists of two chambers 70 and 71 filled with fluid;
These communicate with each other through controlled apertures. The delimitation of the chambers 70 and 71 is provided by an approximately annular projection 72 of the valve spool 7. The controlled opening,
This is given by the difference between the diameter of the protrusion 72 and the inner diameter of the hole inside the valve body 6. An overflow hole for fluid from chamber 71 is indicated at 73. The operating mechanism of the hollow puncher finally has an electrical circuit for operating the valve spool and for the automatic return of the head of the hollow puncher immediately after the completion of the punching operation.

The electrical circuit is illustrated in detail as a wiring diagram in FIG. The electrical circuitry of the hollow puncher is essentially of a conventional type. In this electrical circuit there is a transformer T, from which two voltage power bows 1 are drawn through a first winding A1 and a second winding A2.

The voltage supplied from winding A1 is approximately 24 volts. , while the voltage supplied from winding A2 is approximately 110 volts. Both are alternating voltages. The voltage supplied from winding A2 is applied to electromagnet E to operate valve spool 7.
Excite 1. Electromagnet E1 is connected to a conventional type control circuit, shown generally as block B in FIG. 7, for energizing electromagnet E1.

Block B is connected to two sets of switch means C and D. In particular, the set of switch means C has three switch means Cl, C2 and C3, while the set of switch means D has a single switch means C4. The voltage supplied from winding A1 is rectified by a diode bridge P, at the output of which
There is an RC filter, a ground S, and a conventional type circuit shown as block E for de-energizing electromagnet E1. The circuits shown schematically as PROC B and PROC E in FIG. 7 are reciprocally linked so that when one is active, the other is inactive. this is,
For example, by connecting a first set of the switching means to circuit B and a second set to circuit E through a multi-contact relay. When the first set of switch means is open, said second set is closed;
Or vice versa. Said reciprocal linkage is made by two switch means U1 and U2, connected schematically by the dotted line and inserted into both circuits, so that when one is open, the other is closed. There is. This switch means U1
and U2 are linked to the operation of electromagnet E1, and when electromagnet E1 is energized to lower the head, one switch means U1 is closed and the other switch means U2 is opened. In particular, said block E represents the circuit in which is wired an automatic delay selection device for the return of the hollow punch head immediately after the completion of the punching operation.

Said circuit comprises a first set F of switch means and a second set G of switch means.

Said first set of switch means F has three switch means Cl, C2 and C3, while the second set of switch means G has a single switch means C4. The switch means Cl, C2, C3, Cl, C2 and C3 are connected to a set of three push buttons Pl, P2 and P3.

In particular, switch means C1 and C1 are connected to push button P1, while switch means C2 and C2 are connected to push button P2.
and the switch means C3 and C3 are connected to the pushbutton P3.
It is connected to the. Switch means C4 and C4 are connected to a single pushbutton P4. Corresponding to the first set F of the switching means, a potentiometer R already used in the known electrical circuit for the operation of the hollow punching machine is connected, and the punching machine immediately after the completion of the punching operation is connected. It will also be understood that adjusting the delay for the return of the head. Two resistors R2 and R correspond to the switching means C2 and C3.
These resistors with different resistance values constitute a part of the automatic delay selection device, and together with the capacitor included in the block E, form a time constant circuit. The charging time of the capacitor is adjusted by the resistance values of R2 and R3, and the operation of the circuit E that de-energizes the electromagnet E1 is automatically delayed by this charging time. No resistor is provided in correspondence with the switch means C1, so that closing this switch means does not cause any delay in the return of the hollow punch head. The manner in which the aforementioned operating mechanism functions is as follows.

That is, assuming that the machine is at rest, ie in the head-stop phase, the valve spool 7 and the valve body 6 are in staggered positions as shown in FIG. The fluid supplied by the pump is forced into the suction duct 8 and passes through the projections 13 and 14 forming the port, from where it passes through the passage 9 leading to the first chamber in the cylinder and into the This creates the necessary pressure to maintain the head in the rest position.

This pressure is typically about 1.7 kg/Cnl2.

Said fluid is also conveyed through a port created by slightly offset protrusions 17 and 18 into a passage 10 leading to a second chamber of the cylinder and into a second discharge duct leading to the second chamber. It will be done. It will also be understood that said first exhaust duct is completely closed. Then, depending on the required delay, said three pushbuttons P,,P.

and P, is pressed, causing a downward movement of the valve spool 7 inside the valve body 6 by means of the electromagnet E,. (FIG. 2) Fluid thus flows from the suction duct 8 into the passage 10 leading to the second chamber 32 of the cylinder, thereby creating the pressure necessary for lowering the head of the hollow puncher. cause

The discharge duct 12 connected to the second chamber 32 is completely closed, while the passage 9 leading to the first chamber is completely closed with respect to the suction duct 8 and the fluid discharge connected to the first chamber 31 of the cylinder. It is connected to the duct 11.

This is the stage where the material on the table of the hollow puncher is actually punched out. At the end of this punching operation, the head of the hollow puncher is returned to its original position. This return begins after a certain delay, the actual delay being when the three pushbuttons P,,P are activated. and P. Depends on which one is pressed. If in fact P, is operated, there is practically no delay in closing said switch means C, and C. If P is operated, said switch means C.

and C. is closed, resistor R as well as the resistance of potentiometer R.
A certain delay is obtained which also depends on the value of . When pushbutton P is pressed, switch means C is activated.

and C. is closed, and not only the resistance of the potentiometer R but also the resistor R,
A certain delay is obtained which also depends on the value of . However, the value of resistor R is resistor R. It's not the same as the one. Generally resistor R. The value of is the resistor R. higher than that of The push button P is for ensuring work safety, and
Push buttons P,,P.

,P. The machine is activated by pressing any one of them simultaneously. Push buttons P,,P. ,P. and P
. The operation of the machine continues only when the buttons are pressed at the same time, and the operation stops when one of the push buttons is released, ensuring the safety of the operator. Corresponding to the upward return movement of the head of the hollow puncher, and in the case in question, the step corresponding to the upward return movement of the column 4 in the hollow puncher is shown in particular with reference to FIG. is shown.

As soon as the excitation of the electromagnet E, is stopped, as a result of the pressure created by said return spring 23, the valve spool 7 moves upwards, forcing the suction duct 8 into the first chamber 31 in the cylinder.
a passage 9 leading to the cylinder and a passage 10 leading to the second chamber in the cylinder.
communicate with.

The first discharge duct 11 and the second discharge duct 12 are completely closed. The pressure supplied by the infeed pump is the same in the first and second chambers, despite the different areas through which the fluid flows, and in the passages 9 and 1.
Since the protrusions 17 and 1 are in communication with each other, the fluid flows between the protrusions 17 and 1.
8 and through projections 13 and 14 from passage 10 to passage 9.

This fluid joins the fluid supplied by the pump via the suction duct, so that it is as if the pump had increased its supply, thereby reducing the rate of rise of the head to the rate of descent. It is possible to make them almost equal. Fourth
The figure shows the relative position of the valve body 6 and the valve spool 7 when the head of the hollow puncher is near its upper limit.

In particular, the value of the distance from this upper limit is selected to be approximately 2.5 mm from the upper limit according to a preferred embodiment. The cable 25, which loosens when the head begins to move downwards, is fully tensioned when the head rises, and as the head approaches the upper limit, the valve spool 7 is moved downwards by the cable 25. It is stretched and located in the state shown in FIG.

As a result, preparations are made for communicating the passage 10 with the second discharge duct 12 through the port formed by the projection 21 and one of the projections 20. The suction duct 8 communicates only with the passage leading to the first chamber of the cylinder, so that a reduction in the rate of rise of the head occurs.

Said valve spool 7 moved by cable 25
As continues its downward movement, this speed continues to decrease because the path created by projections 13 and 14 continues to become smaller. As soon as the head 5 reaches its upper limit, the valve spool 7 stops. This occurs when the passage created by projections 13 and 14 is such that the pressure necessary to maintain the head can be maintained.
This pressure is limited and maintained along the path created between projections 17 and 18 (FIG. 1). The fluid delivery supplied by the pump will only flow when its pressure is balanced by the pressure caused by the weight of the head 5 acting on the area of the first chamber in the cylinder. From this point on, the passageway opening will be automatically adjusted. In this way, vibrations in the head section of the hollow puncher due to sudden stops occurring immediately after the completion of the upward return run can be avoided.

It will be appreciated that the first discharge duct 11 is completely closed.

Another feature of the operating mechanism that forms the subject of the invention is that by simply moving an operating handle 30 connected to a pulley 29, the position of the head 5 of the hollow punching machine can be adjusted with respect to the table. This means that it is possible.

In fact, when the operating handle is turned in one direction or the other, the pulley 29 rotates about its own axis, thereby increasing the length of the cable 25 to be wound around the pulley 29. , become smaller. This causes the valve spool 7 attached to the cable 25 to be lowered or raised, and thus the head to be raised or lowered by a certain distance. In fact, if you want to lower the head, all you need to do is step 5.
This means moving the operating handle 30 counterclockwise as indicated by F1 in the figure.

The cable is thereby wound onto the pulley 29 and the valve spool 7 is lowered inside the valve body 6. As a result, the fluid flows from the suction duct 8 to the passage 10, while the passage 9 is brought into communication with the first discharge duct 11, and the head is lowered as described above. Once the valve body 6 and the valve spool 7 are lowered according to the above requirements, the cable 25 is loosened when the head is lowered, so that the valve spool 7 is lowered.
It is raised by the force of the return spring 23 and returns to the position shown in FIG. 1 again. If the head is to be raised, the operating handle 30 must be moved clockwise as indicated by arrow F2 in FIG. This allows cable 2
5 is loosened, and the valve spool 7 is raised inside the valve body 6 by the force of the return spring 23. If this displacement exceeds 2.5 mm, the passage 10 is made to communicate with the passage 9,
The head is then raised for the reasons mentioned above. Otherwise, if the displacement is less than 2.5 mm,
As seen in FIG.
The head slowly rises to a height where its weight and pressure are balanced. 2.5m given here
The value m is determined by the desired dimensions of the valve body 6 and the valve spool 7, and is by no means fixed.

Similarly, when the head 5 of the hollow puncher is raised the desired distance, the operation described above returns the valve spool 7 to the position inside the valve body 6 shown in FIG. Modifications may be made to the invention without departing from the basic design or the scope of the claims.

[Brief explanation of the drawing]

1 to 4 are cross-sectional views of a hydraulic circuit valve in its various working positions. FIG. 5 is a partially sectional side view of the entire hollow punching mechanism with the operating mechanism that is the subject of the invention. FIG. 6 is a sectional view showing details of the lower part of the cylinder and the two chambers within the cylinder. FIG. 7 is a wiring diagram of an electric circuit belonging to the operating mechanism. Explanation of symbols, 1... units, 2
...Table, 3... Upright body, 4...
...Column, 5...Head, 6...
Valve body, 7... Valve spool, 8... Suction duct, 9, 10... Passage, 11...
First discharge duct, 12...Second discharge duct, 1
3...First protrusion, 14...Second protrusion,
15... Third protrusion, 16... First pair of protrusions, ]7... Fourth protrusion, 18...
5th protrusion, 19...6th protrusion, 20...
・Second pair of protrusions, 21...Seventh protrusion, 22・
... Valve stem, 23 ... Return spring, 24.
...Tightening nut, 25...Cable, 2
6, 27, 28, 29... Pulley, 30...
...Operation handle, 31...First chamber, 32...
...Second chamber, 33...Top wall of large diameter portion of piston, 34...Leak prevention member, 35...
Screw, 36...lower wall of the large diameter part of the piston,
37...Piston, 50...Leakage member or cover, 70, 71...Chamber, 72...
...Protrusion, 73...Overflow hole, A1...
...First winding, A2...Second winding, B...
...Control circuit, C...Set of switch means)
C1 la C2 la C39C4 la Cl9C29C39C4゜゜゜...switch means, D...set of switch means, E...circuit, E1...electromagnet, F, G... ...Setting the switch means, P...
...Diode bridge, Pl, P2, P3, P4
......Push button, R...Potentiometer, R
2, R3...Resistor, RS...Filter, S...Ground, T...Transformer, U
l, U2...Switch means.

Claims (1)

[Scope of Claims] 1. A hydraulic circuit for operating a cylinder connected to the head of a hollow punching machine, the hydraulic circuit being a valve having a valve spool slid into a valve body, A fluid suction duct communicates with a first chamber in the cylinder for raising the moving part of the cylinder and a second chamber for lowering the moving part of the cylinder. the valve spool is an operating mechanism for a hollow punching machine, in particular a cantilevered hollow punching machine, controlled by an electric circuit; 7 and the valve body 6 between their relative sliding surfaces, when the moving parts of the cylinder are at rest, the suction duct 8 is connected to the passage 9 leading to the first chamber 31 in the cylinder. , the first exhaust duct 11 communicated through the port and connected to the first chamber 31 is closed, and the suction duct 8 is connected to the second exhaust duct 11 in the cylinder.
means for communicating through a port with said passageway 10 leading to a chamber 32 and a second discharge duct 12 connected to said second chamber 32; when the moving part of said cylinder is lowered for punching; The suction duct 8 is connected to the second
The passage 9 communicating with the passage 10 leading to the chamber 32 and closing the second exhaust duct 12 and the passage 9 communicating with the first chamber 31 communicating with the first exhaust duct 11 is connected to the suction duct 8. means for closing the suction duct 8 with the first chamber 31 when the moving part of the cylinder rises, corresponding to the return of the head of the hollow puncher after completion of the punching operation; the passages 9 and 10 communicating with the second chamber 32, and
means for simultaneously closing both the discharge duct 11 and the second discharge duct 12; the suction duct 8 when the moving part of the cylinder is still rising but nearing the end of its stroke; First chamber 3 in the cylinder
1 , and closes the first exhaust duct 11 , and further connects the second exhaust duct 12 to the passage 10 , which is closed with respect to the suction duct 8 and communicates with the second chamber 32 . means for bringing the valve spool 7 into communication through the constriction, the valve spool 7 having means controlled by the electrical circuit for moving the valve spool 7 in a direction corresponding to the lowering of the cylinder; Means for constantly biasing the valve spool in the reverse direction when the operation of the means controlled by the electric circuit ceases, and for gradually stopping the movement of the valve spool at the end of the return of the head after the completion of the punching operation. means for connecting the valve spool and the head, said electric circuit further comprising automatic delay means for delaying the start of the lifting of the head 5 of the hollow puncher, said automatic delay means An operating mechanism for a hollow punching machine, characterized in that a delay time can be selected prior to starting operation of the machine. 2. A hydraulic circuit for operating a cylinder connected to the head of the hollow punching machine, said hydraulic circuit being a valve having a valve spool slid into a valve body, and raising the moving part of said cylinder. A valve is provided which allows a fluid suction duct to communicate with two passages which communicate with a first chamber in the cylinder for the purpose of lowering the moving part of the cylinder and a second chamber for lowering the moving part of the cylinder. The valve spool is an operating mechanism for a hollow punching machine, in particular a cantilever type hollow punching machine, which is controlled by an electric circuit, and the valve spool 7 and the valve body 6 are connected to each other. means that between the two relative sliding surfaces, when the moving part of the cylinder is at rest, the suction duct 8 is communicated with the passage 9 communicating with the first chamber 31 in the cylinder through a port portion. , and closes the first exhaust duct 11 connected to the first chamber 31, and further closes the suction duct 8, which is connected to the passage 10 communicating with the second chamber 32 in the cylinder and the second chamber 32. means for bringing the suction duct 8 into communication through a port with a second discharge duct 12 leading to the second chamber 32 when the moving part of the cylinder is lowered for punching; and closes the second exhaust duct 12 and further communicates with the first chamber 31 that communicates with the first exhaust duct 11.
means for closing with respect to said suction duct 8; said suction duct 8 when the moving part of said cylinder is raised, corresponding to the return of the head of said hollow puncher after completion of the punching operation; means for simultaneously communicating with the passages 9 and 10 communicating with the first chamber 31 and the second chamber 32, and for simultaneously closing both the first discharge duct 11 and the second discharge duct 12; The moving part of
When the suction duct 8 is still rising but approaching the end of its stroke, the suction duct 8 is brought into communication with the passage 9 leading to the first chamber 31 in the cylinder, and the first
closing the exhaust duct 11 and further closing the passage 10 with respect to the suction duct 8 leading to the second chamber 32;
means for communicating the second discharge duct 12 through the constriction, and the valve spool 7 is connected to the electric circuit for moving the valve spool 7 in a direction corresponding to the lowering of the cylinder. and means for constantly biasing the valve spool in the opposite direction when the operation of the means controlled by the electric circuit is stopped, and when the return of the head after the completion of the punching operation is completed. In order to gradually stop the movement of the valve spool, the valve spool is integral with the end of the connecting cable 25 to the head 5, the free end of the cable being
wrapped around an operable pulley 29 rotatably mounted on the head 5, furthermore said electrical circuit comprising automatic delay means for delaying the start of the lifting of the head 5 of the hollow punching machine; An operating mechanism for a hollow punching machine, wherein the automatic delay means is capable of selecting a delay time prior to starting operation of the hollow punching machine. 3. A hydraulic circuit for operating a cylinder connected to the head of the hollow punching machine, said hydraulic circuit being a valve having a valve spool slid into a valve body to raise the moving part of said cylinder. A valve is provided which allows a fluid suction duct to communicate with two passages which communicate with a first chamber in the cylinder for the purpose of lowering the moving part of the cylinder and a second chamber for lowering the moving part of the cylinder. The valve spool is an operating mechanism for a hollow punching machine, in particular a cantilever type hollow punching machine, which is controlled by an electric circuit, and the valve spool 7 and the valve body 6 are connected to each other. means that between the two relative sliding surfaces, when the moving part of the cylinder is at rest, the suction duct 8 is communicated with the passage 9 communicating with the first chamber 31 in the cylinder through a port portion. , and closes the first exhaust duct 11 connected to the first chamber 31, and further closes the suction duct 8, which is connected to the passage 10 communicating with the second chamber 32 in the cylinder and the second chamber 32. means for bringing the suction duct 8 into communication with the second exhaust duct 12 through the port when the moving part of the cylinder is lowered for punching;
The passage 9 communicating with the passage 10 leading to the chamber 32 and closing the second exhaust duct 12 and the passage 9 communicating with the first chamber 31 communicating with the first exhaust duct 11 is connected to the suction duct 8. means for closing the suction duct 8 with the first chamber 31 when the moving part of the cylinder rises, corresponding to the return of the head of the hollow puncher after completion of the punching operation; the passages 9 and 10 communicating with the second chamber 32, and
means for simultaneously closing both the discharge duct 11 and the second discharge duct 12; the suction duct 8 when the moving part of the cylinder is still rising but nearing the end of its stroke; First chamber 3 in the cylinder
1 , and closes the first exhaust duct 11 , and further connects the second exhaust duct 12 to the passage 10 , which is closed with respect to the suction duct 8 and communicates with the second chamber 32 . means for bringing the valve spool 7 into communication through the constriction, the valve spool 7 having means controlled by the electrical circuit for moving the valve spool 7 in a direction corresponding to the lowering of the cylinder; Means for constantly biasing the valve spool in the reverse direction when the work of the means controlled by the electric circuit has stopped, and for gradually stopping the movement of the valve spool at the end of the return of the head after the completion of the punching operation. means for connecting the valve spool and the head, said circuit further comprising automatic delay means for delaying the start of the lifting of the head 5 of the hollow puncher, said automatic delay means A delay time can be selected prior to the start of operation, said automatic delay means including at least three switch means C_1 in said electrical circuit operating said spool 7.
. An operating mechanism for a hollow punching machine.