DE1118746B - Safety device on cutting machines for paper, cardboard or the like. - Google Patents

Description

Safety device on cutting machines for paper, cardboard or the like. The invention relates to a safety device on cutting machines for paper, Cardboard or the like with a removable knife and one that clamps the material to be cut Clamping bar.

For larger cutting machines, which are used to cut whole stacks of sheets serve, it is necessary to use the knife blade if it is due to a long period of operation has become blunt to replace. Since this knife is heavy and unwieldy, it is it is advisable for safety reasons to have special devices for raising and lowering the knife in the correct position without any risk of injury to the operator to be provided. It is also desirable that the cutting mechanism during which the operator replaces the knife is necessarily switched off, any possibility of accidental actuation of the cutting mechanism and a then eliminate possible injury to the operator's hands or arms. For this reason, it is known, on the free longitudinal edge of the front of the clamping bar, which is hydraulically operated, holes for clamping screws to support the knife to be provided when installing and removing the same; This allows the clamping bar, as he under relatively little pressure and with relatively little lifting and lifting Lowering speed works as a lifting device for installing and removing the knife be used.

The object of the invention is to create a safety device for cutting machines of the type described above, which automatically switch on the knife drive during installation and removal of the knife, d. H. so during its attachment to the clamping bar, makes impossible.

According to the invention, the clamping screws, by means of which the knife can be attached to the clamping bar, in a control circuit switched on for the knife drive in such a way that the interruption of the circuit when removing the clamping screws for the purpose of fastening the knife to the clamping bar it makes switching on the knife drive impossible.

Such a safety device is available on cutting machines with any Knife drive applicable; in any case causes the removal of the clamping screws via electrical, electro-hydraulic or fully hydraulic auxiliary controls a Switching off the knife drive. With cutting machines with electrically switchable Cutting knife drive coupling and a knife drive locking, in the Control line of the clutch arranged safety stop, the arrangement according to the invention be affected in such a way that in the control circuit for actuating a solenoid the clamping screws for the electrically switchable coupling are switched on in such a way that that the coupling is released when the clamping screws are removed. So if the Klenun screws from a control box in which they can be used during normal operation of the cutting machine are housed, can be removed in order to attach the knife to the clamping bar, so the cutting knife can no longer be driven because it is in its drive activated clutch is open. It can also be a line to the control circuit connected and with a knife drive rest switch and a control relay be provided for simultaneously influencing the clutch and the solenoid.

For cutting machines with hydraulically operated clamping bars and two Valves, one of which is used to reduce the clamping pressure outside the clamping period and the other is used to reverse the movement of the clamping bar, according to the invention the solenoids of the valves are connected to the control circuit with lines.

An exemplary embodiment of the invention is shown in the drawing.

Fig. 1 is a schematic end view of a cutting machine according to of the invention and shows the Control panel in which the fasteners for the knife are housed; FIG. 2 is a schematic side view of FIG in Fig. 1 machine and shows the mutual position of the knife blade and of the clamp holder; Fig. 3 is an enlarged partial section of the knife blade and of the clamp holder, with the fasteners for the purpose of receiving the knife in place and are brought to the spot; the dashed lines show the position of the clamp holder, when the knife is removed from its holder; Fig. 4 is a schematic plan view the drive mechanism for the cutting device; Fig.5 is a partial section through the control box of FIG. 1 and shows how the knife mounting parts in their Press the storage position switch in the electrical circuit; Fig. 6 is a a schematic circuit diagram showing the mode of operation and control of the machine; Figure 7 is a schematic diagram of the hydraulic circuit for actuating the Stacking clamp holder.

According to the drawings, which show a preferred embodiment of the invention, the cutting machine has a base plate 10 with a one-piece side frame 11 or 12, with bearings being provided for various working parts of the machine. A work table is mounted on the frame, which protrudes over the frame on the front or operating side and forms a support surface for the material to be cut.

There are front guide tracks 16 and 17, the guide channels to guide and align the movement of the knife bar 20. A locking part 21 connects the upper ends of the two guide pillars and extends over the entire width of the machine; it increases the rigidity and rigidity of the machine.

The knife bar 20 has guide surfaces 22 at both ends, certain parts of which slide in the guides formed by the columns 16 and 17. The knife bar has on its underside an inclined surface shown in Fig. 2 at 25, on which the cutting blade 26 by means of screws 27 embedded in the knife bar is attached.

The mechanism for operating the knife is designed in such a way that that the cutting forces are applied exactly in the plane of movement of the knife, through a simple system of levers and arms that allow the knife to move quickly result and at the same time a sideshift on the knife blade or knife bar avoid that disturb the uniformity of the cutting process or make one superfluous or cause excessive wear and tear.

For this purpose are at the opposite ends of the knife bar downwardly projecting arms 30 and 31 are provided, the openings for receiving pins 32 and 33, which, as shown, next to and approximately in the plane of the lower edge of the knife lie. The connections of the two opposite ends of the knife are such arranged that they give a double vision. This means that the knife moves down and sideways during the cutting stroke; however, since the opposite Ends of the knife face each other beforehand in different starting height positions the cutting table, one end moves down more than the other End so that the knife at the end of its stroke with its edge parallel to the work table and is in exact contact with the usual cutting support. This requires a certain lateral movement of the knife to the work table, the resulting one Sliding effect leads to the desired cutting results.

This mechanism has a lever 35 on the left-hand side which is pivotably mounted on the pin 32. This lever has an adjustable threaded connection 36, by means of which the effective lever length can be changed, and its lower end is pivotably connected by means of a pin 37 to an arm of a three-armed angle lever 40 which is pivotably mounted in the frame 11 about the center line of the pin 41. A suitable protrusion on the outside of the knife bar slides in a guide 42.

The opposite end of the knife rod is articulated by means of a pin 33 to a lever 45 which has an adjustable threaded connection 46 , by means of which its effective length can be changed. The lever 45 is articulated at its lower end by means of a pin 47 to an arm of a two-armed angle lever 49 which is pivotably mounted in the frame 12 by means of a pin 50. A second arm 51 of the three-armed angle lever 40 receives a pin 52 , by means of which it is pivotably connected to a cross rod 53 which is connected at its other end at 56 to the lower arm 57 of the two-armed angle lever. In this way, as shown in FIG. 1, the two angle levers must pivot jointly as a result of the cross bar 53, each angle lever causing the associated end of the knife bar to be actuated by a different path by the associated end of the knife bar at the end of its downward stroke in a horizontal position is brought.

The knife rod 20 is driven via a connecting rod 60 which is articulated to the third arm 61 of the three-armed angle lever 40. The connecting rod is driven by a crank pin 62 which is carried by a crank arm 63 which in turn is suitably supported in the subframe of the machine. The drive mechanism is shown in FIG. 4, from which it can be seen that the crank arm 63 is rotatably supported on the main shaft 65.

The shaft 65 is driven by a gear 66 which is fastened on the shaft and is driven by means of a pinion 67 which is fastened to a large gear 68. The pinion and the large gear 68 are rotatably mounted on a stationary shaft 70. The gear 68 is driven by a pinion 71 which is attached to a countershaft 72 which in turn is rotatably mounted in the machine frame.

The drive power is provided by a drive motor 75 which is arranged behind the machine and is expediently carried by the rearwardly extending end of the fixed shaft 70. The engine has a drive pulley 76 over which a number of V-belts 77 are placed, which also frictionally engage the periphery of a flywheel 80 and introduce the drive torque into it. The flywheel 80 is carried by a shaft 81 which works as a drive shaft and is arranged coaxially with the countershaft 72, but at a certain distance therefrom.

To connect the drive shaft 81 and the countershaft 72 , a clutch 82 and a brake 83 are provided. The clutch is an electromagnetic clutch so that it can be brought into engagement at any time by energizing its coils to operate the cutting mechanism each time power is applied to the machine.

Also attached to the main shaft 85 is a pock-shaped safety plate 85 which rotates with the shaft. A safety stop pin 86 protrudes into the path of movement of the plate 85 and prevents further rotation of the same in the event of a failure in the machine operating mechanism. The safety stop 86 is actuated by a solenoid 87 which enables the stop pin 86 to be automatically withdrawn from the path of travel of the plate 85 when the motor 75 is turned on.

When cutting relatively thick stacks or stacks of paper material, it is essential that the stack is held precisely during the operation of the knife bar 20 so that the individual sheets are all the same dimensions and have no jagged, torn edges. This is normally effected by a clamp holder 90 which moves next to the knife bar 20 in the direction of the work table 15 and away from it. The immediate juxtaposition of the knife bar 20 and the clamp holder 90 can be clearly seen from FIGS. The movement of the clamp holder is caused by a known parallel linkage. This linkage has downwardly extending arms 91 and 92, at the lower ends of which levers 93 and 94 are pivotably articulated. These levers are pivoted to the arms of angle levers 97 and 98, respectively, by means of pins 95 and 96. The lever 97 is pivotably mounted on the front end of the stationary shaft 70, while the lever 98 is pivotably mounted on a pin 100 mounted in the side frame 12.

A rod 101 connects the opposite ends of the angle levers for corresponding movement, and the power is introduced by a lever 102 pivoted at 103 on the angle lever 98. A hydraulic cylinder 105 with a piston 106 displaceable therein is pivotably connected to the lever 102 by means of a bolt 107. Through this mechanism, the clamp holder is supplied with the force required for pressing against the material to be cut in a predetermined size, as well as the force for lifting the clamp holder into its raised position above the material to be processed on the table.

The hydraulic system for actuating the clamp holder 90 is shown in FIG. 7, the hydraulic cylinder 105 with the piston 106 being shown schematically. The hydraulic pressure in the system is generated by a pump 110 and the pressure is determined by a pressure relief valve 111, one side of which is connected to a lower pressure reflux system or tank T. A valve 112 and a pressure gauge 113 are connected to the hydraulic system via a line 114 which opens into the line 115 which connects the pump 110 to the pressure relief valve 111 . A check valve1116 is connected in the hydraulic system between the liquid pump and the hydraulic cylinder 105 and prevents the liquid from flowing back in the direction of the pump. In addition, a pair of fluid control valves 120, 121 are built into this line part, which are located in lines 122, 123 which connect the hydraulic cylinder to a reversing valve 125. The valve 125 is operated by a solenoid 126 to determine the direction of flow of the liquid through the valve and thus the upward or downward movement of the piston 106. In the setting shown in the drawing, the pressure fluid flows into the upper part of the cylinder 105 so that the Liquid contained in the lower part of the cylinder flows back through the line 123 into the tank T, from which the pump 110 can suck.

Since it is often desirable to operate the clamping holder with a relatively low pressure compared to the relatively high hydraulic pressure when pressing the clamping holder for the purpose of clamping a stack of material against the work table, an additional hydraulic line 127 is provided, into which a drain valve is located behind a needle valve 131 130 is turned on, which is operated by means of a solenoid 132 . The pressure levels in the hydraulic system are controlled so that there is a minimum operating pressure in the main line 115 at all times which is sufficient to hold the clamp holder 90 in its uppermost position without the aid of any mechanical holding or locking devices. This minimum pressure is also maintained when the knife blade 26 is to be replaced, because the operator is handling the knife directly during this period of time and accidental actuation of the clamp holder with high pressure could lead to serious injury to the operator.

As a result of the cutting machines of the type described above adhering Various safety precautions are already dangerous in the manufacture of such machines been taken to prevent accidental actuation of the knife blade and to allow actuation only when the operator's hands and arms have been completely removed from the vicinity of the knife blade. An example for such a safety device is the safety stop mentioned above 86. Obviously, when a leaf is so dull it must be replaced the operator has to move the heavy and unwieldy sheet that is used for ordinary Relationship is still quite sharp. A large part of the existing ones Danger can be eliminated by using mechanical suspension devices of the sheet during the replacement process. be provided so that the operator does not have to hold the sheet itself.

One way of suspending the knife blade while it is being replaced is to use fastening parts in the manner of buttons 135, which can be temporarily fastened to the clamp holder 90 between its ends, after which the clamp holder is moved into a position such that the fastening parts 135 are immediately below of the knife blade to be supported. Such an arrangement is indicated in FIG. 3, the fastening parts 135 being shown in that position which they would assume during the removal of the knife blade 26 from the knife bar 20.

If the knife drive mechanism could be turned on with the fasteners screwed into the clamp holder 90 , the cutting and clamping mechanism could be severely damaged and the operator who may have his hands in close proximity could be seriously injured. For this reason, according to the invention, a circuit is provided which is switched into the drive motor circuit and the hydraulic circuit in order to prevent the actuation of the knife bar 20 and to allow the clamp holder 90 to operate only with low hydraulic pressure.

As FIG. 6 shows, a series of circuits are connected in parallel between the feed lines L 1 and L 2. The first line 140 includes a suitable main switch 141, a control relay 142 and a set of relay contacts 142a. This line 140 is first connected to voltage via the line 143 by closing the switches 144 and 145 connected in series. The line 143 forms a bypass line for the relay contacts 142 a until the point in time at which the relay 142 is closed, whereby it closes the contacts and keeps the circuit permanently under voltage. The line 146 is normally open, are closed to the series-connected switches 147 and 148 to close the circuit through a normally closed knife drive sleep switch 149, a second set of relay contacts 142 b and a second control relay 150th When the control relay 150 closes, its relay contacts 151a on line 151 are closed so that they bypass switches 147 and 148 and keep this circuit under voltage. A third line 155 is closed when the control relays 142 and 150, which close their associated relay contacts 142 c, 150 b, and the switches 156 and 157 connected in series are closed. The switches 156, 157 are closed at the same time as the switches 147 and 148 are closed and the switches 144 and 145 are opened.

In addition, a second pair of series-connected switches 158, 159 is provided in the line 155, the closing of which causes the clutch 82 to be actuated. In parallel with the three circles described above, a ring line 165 is connected, in which relay contacts 150c controlled by the relay 150 are switched on, so that this line is closed only when the circuit 146 is closed at the same time. When the contacts 150 c are closed, the solenoid 126 receives voltage and brings the valve 125 into the position in which pressure fluid is fed to the cylinder 105 through the line 123 , so that the piston 106 is moved upwards and the clamp holder 90 is moved downwards.

Furthermore, a line 170 runs between the feed lines L 1 and L 2, which contains a pair of series-connected switches 158 a, 159 a , which are operated simultaneously and together with the switches 158, 159, so that the solenoid 87 of the safety stop is turned off. The safety stop 86 is then no longer retracted and movement of the knife bar actuation mechanism is prevented. In order to prevent the solenoid 87 from being switched on unintentionally, relay contacts 150 d are switched on in the line 170, so that it is necessary to close the control relay 150 before the solenoid 87 can be switched on in order to disengage the safety stop 86 from the safety plate 85 to pull. A last circuit 175 is connected to the circuit 170 on the output side of the switches 158 a, 159 a , so that opening these switches also results in the solenoid 132 controlling the drain valve being switched off. When this solenoid is switched off, the drain valve is adjusted in such a way that only a small hydraulic actuation pressure is supplied to the clamp holder 90.

The switches 158, 158 a, 159 and 159 a are designed as two-pole switches which are arranged in a switch box 180 (Fig. 1) which is attached to the front of the cutting machine. During normal operation, the fasteners 135 are pushed into the switch box 180 such that their ends press against the contact buttons 181, 182 and keep the switches closed. Although it is shown that the circles 155, 170 are broken when the fasteners 135 are removed from the switch box 180 by opening the two-pole switches; however, it is also possible to use other devices for interrupting the lines in connection with the fastening parts 135.

If it is necessary to replace a knife blade 26, the operator removes the fastening parts 135 from the switch box 180, the two electrical lines 155 and 170 being interrupted and the solenoids 87 and 132 being switched off. As a result of the disconnection of the line 155, the coupling 82 can no longer connect the motor 75 to the main shaft 65 and cause the cutting mechanism to work. Since the solenoid 87 is turned off at the same time as the clutch in the actuation circuit is turned off, the safety stop 86 cannot be pulled out of its engagement with the plate 85. Furthermore, by switching off the solenoid 132, the drain valve 1130 is opened to the tank, so that only the low working pressure for the clamp holder 90 is available.

After they have been removed from the switch box 180, the buttons 135 are attached to the clamp holder 90 after the latter has been moved to its lowest position with low pressure and the clamp holder switch 149 has been toggled to open the circuit 146 and switch off the Sfduerrelais 150. This opens all relay contacts 150 a to 150 d. By opening the relay contacts 150c, the solenoid 126 is removed from the circuit and the valve 125 is switched so that the pressure fluid flows through the line 122 into the cylinder 105 and through the line 123 out of the cylinder 105 . As a result, the piston 106 moves in the cylinder 105, and the clamp holder 90 is moved in the direction of the knife bar 20 upwards.

The upward movement of the clamp holder is continued until the fastening parts 135 come to rest at the bottom of the knife blade 26, as shown in FIG an injury to the operator's hands or arms is to be feared. As soon as the old sheet has been removed, a new one can be inserted. The fastening parts 135 are now pushed back into the switch box 180, as a result of which the switches 158, 158a, 159 and 159a are closed and the electrical and hydraulic circuits are thus returned to their initial state. The accommodation of the fastening parts in the switch box has the additional advantage that they can be accessed at any time if necessary.

Claims (4)

PATENT CLAIMS: 1. Safety device on cutting machines for paper, cardboard or the like with a removable knife and a clamping bar which clamps the material to be cut and which has bores on the free longitudinal edge of the front side for clamping screws to support the knife during installation and removal, characterized in that that the clamping screws (35) are switched into a control circuit (L1, L2, 155) for the knife drive in such a way that the interruption of the circuit when the clamping screws are removed for the purpose of fastening the knife (26) to the clamping bar (90) makes it impossible to switch on the knife drive power. 2. Safety device according to claim 1 in a cutting machine with electrical switchable cutting knife drive coupling and a knife drive locking, Safety stop arranged in the control line of the clutch, characterized in that that in the control circuit (155, 170) for actuating a solenoid (87) for the electrically switchable coupling (82) the clamping screws (135) switched on in this way that the coupling is released when the clamping screws are removed. 3. Safety device according to claim 1 and 2, characterized in that a line (146) is connected to the control circuit (155, 170) and with a knife drive rest switch (149) and a control relay (150) for simultaneously influencing the clutch (82) and the solenoid (87) are provided. 4. Safety device according to claim 1 with a hydraulically operated clamping bar and two valves, one of which is provided to reduce the clamping pressure outside the clamping period and the other to reverse the movement of the clamping bar, characterized in that the solenoids (126, 132) of the valves ( 125, 130) with lines (165, 175) are connected to the control circuit (146, 155, 170). References considered: U.S. Patent Nos. 2182 018, 1743 946.