EP1724101B1 - Safety method for pressing tools - Google Patents

Abstract

Apparatus has a sensor (27) provided to detect a closure gap and/or a pressing slot. The sensor is connected with a pressing piston and a pressing cylinder (31) for pressing and/or clamping a work piece in such a manner that the cylinder and the piston are not activated or a pressing or clamping process is not executable or is blocked, when the dimension of the gap or the slot is equal or larger than a preset distance value. A tension spring (23) drives a pressing and/or clamping tool, while inserting the work piece in a closing direction with a force. An independent claim is also included for a method for operating a pressing and clamping tool and/or a machine.

Description

The present invention relates to a method for protecting an operator in press machines (hereinafter "press machine") according to claim 1.

In semi-automatic and manually operable press machine tools, pneumatic presses, clamping devices and the like, there is a high risk of injury to the operator, especially when inserting to be pressed materials or workpiece parts. In case of improper insertion or improper operation, especially hands, especially fingers, are in serious danger of injury.

Accordingly, there are regulations for the protection of operators in pressing tools, which has led to the attachment of protective covers, safety covers and the like. The disadvantage of these guards is that they can be polluted, scratched after a certain period of use, etc. and thus the view to the work area is severely limited. Also, the work is complicated by such cover elements.

EP 0 983 840 B1 discloses a press in which the actual pressing of a workpiece takes place via a cam drive. The cam has a bulge, in which a cam follower is displaceable for alignment of the bulge with the pressing direction, so that a relative movement of the press inserts is independent of the operation of the cam drive is possible for the insertion of the workpiece between dies.

US 2,400,486 . US 3,613,981 and US 6,148,985 relate to protective arrangements for presses, in which the relative movement is brought about by the drive of the pressing arrangement both during the actual pressing operation and during the insertion of the workpiece in the press inserts. If a body part of the operator is located between the press inserts, the drive movement of the drive is interrupted.

EP 0 449 664 A2 discloses a method according to the preamble of Ansprunchs 1 and discloses a hydraulic actuating cylinder which carries a tool in an end region. The hydraulic actuating cylinder is guided in a vertical direction displaceable in a bore of a tripod. The movement in the hole is limited by in that a radially oriented guide pin is slidably guided in a vertically oriented slot of the stand. By means of a hand lever, the actuation of which can be assisted by a pneumatic cylinder, the hydraulic actuating cylinder can be set from an upper end position defined by the upper end of the oblong hole, in which a workpiece can be arranged below the tool, to a likewise predetermined by an end region of the oblong hole lower end position to be moved. If a switch detects that the hydraulic actuating cylinder has reached the lower end position, the vertical displacement degree of freedom of the hydraulic actuating cylinder is pneumatically locked relative to the stand, so that the hydraulic actuating cylinder is rigidly fastened to the stand. At the same time, the hydraulic actuation of the hydraulic actuating cylinder is released, with which the actual pressing stroke can take place. About an adjustment of the hydraulic adjusting cylinder, the position of the workpiece at the beginning of the hydraulic pressing operation can be changed.

Further prior art is out DE 1 577 201 A known.

It is therefore an object of the present invention to propose a method for protecting operating personnel when working with press machines, which, however, in no way negatively influence or complicate the operation.

According to the invention, the object is achieved by means of a method according to the wording of claim 1.

Proposed is a method for protecting an operator in press machines, which uses at least one detection means or a sensor (hereinafter "sensor") for the detection of the closing gap or Verpressschlitzes (hereinafter "Verpressschlitz"), the sensor in such a way with a drive for the Pressing or clamping (hereinafter "compression") is operatively connected, that with a size of Verpressschlitzes equal to or greater than a predetermined distance value, the drive is not activated or the pressing process is not feasible or blocked.

According to the invention, the drive via a slot, which forms a degree of freedom on the one hand for non-activated drive. On the other hand, for activated drive, first a movement takes place along the oblong hole with subsequent performance of the actual pressing process, for which a pin transmits the drive movement and force in an end region of the oblong hole.

At that part of the pressing machine, which is movable or driven for the pressing operation, or on an element which is connected to this part, (here also called "plunger") a mark, a pin, a cam, a recess or the like is arranged , by means of which or by means of which or whose position the size of the injection slot can be determined and which or which is operatively connected to the sensor in order to block or deactivate the drive of the pressing tool when the predetermined value is exceeded.

It is further proposed that a second drive is provided for opening the pressing machine, in particular after performing pressing.

It is further proposed that a further drive means such as a clamping member or a tension spring is provided to drive a press insert, in particular when inserting a workpiece to be pressed or clamped in the closing direction with a force which is such that no injuries to human body parts can be caused.

Again, according to a further embodiment, the second drive engages the above-mentioned part of the pressing machine as preferably on the pin, cam or in the recess or on and is in particular hingedly connected to said part, wherein the second drive is so operatively connected to the sensor when opening the press inserts by means of the second drive, the drive of the pressing machine is blocked or deactivated after exceeding the predetermined distance value of the injection slot.

The entire part is according to a variant with deactivated or blocked drive for the pressing process in the open position and / or in the closing direction, optionally by means of the second and / or further drive, and / or manually stored freely movable or displaceable.

Further preferred embodiments of the arrangement are characterized in the dependent claims.

The arrangement defined according to the invention is particularly suitable for the protection of an operator of a pneumatic, hydraulic or electric crimping press, in particular when using for connecting cables to a cable lug, to a tube terminal, a cable adapter and the like.

Of course, the proposed arrangements according to the invention are generally suitable for all types of pressing and clamping tools.

• Fig. 1 schematisch im Schnitt die wichtigsten Elemente einer Pressmaschine in geschlossenem Zustand,
• Fig. 2 im Schnitt der Pressmaschine aus Fig. 1 in geöffnetem Zustand,
• Fig. 3 die Pressmaschine aus Fig. 1 mit reduziert geöffneten Presseinsätzen in Position geeignet für das Einlegen eines zu pressenden Werkstückes und
• Fig. 4 die Pressmaschine aus Fig. 1 während des Pressvorganges.

The invention will now be explained in more detail by way of example and with reference to the accompanying drawings. Showing:

• Fig. 1 schematically in section the most important elements of a pressing machine in the closed state,
• Fig. 2 in the section of the pressing machine Fig. 1 in open condition,
• Fig. 3 the pressing machine off Fig. 1 with reduced open dies in position suitable for inserting a workpiece to be pressed and
• Fig. 4 the pressing machine off Fig. 1 during the pressing process.

FIG. 1 shows schematically in section the most important components of an inventive pressing or clamping device 1, suitable for example for connecting an electrical cable to a cable lug by pressing or crimping. The pressing tool or the crimping machine 1 initially has a pressing tool insert consisting of an upper and a lower pressing or crimping insert 3 and 5 having interposed recesses 7, in which the pressing process is carried out. The upper crimping insert 3 is held on a cylinder-like plunger 9 which is movable in a sliding bearing 11 in the lifting or lowering direction. Arranged in the ram is arranged a transverse cam 13, on which a lever-like carrier 15 for lifting the crimping or pressing insert 3 articulated on the contour 17 and engages. The lever-like carrier 15 is rotatably mounted about an axis 19. Furthermore, the lever-like carrier 15 is connected to a tension spring 23, whose function will be discussed later. The lever-like carrier 15 is liftable by means of a lifting cylinder 22 and a piston rod 21, which via a pneumatic, hydraulic or electrical supply 24 can be actuated. Finally, the lever-like carrier 15 is located laterally on a sensor 27, which is connected via a circuit 25 to the drive 31, 33 and 34 for the operation of the pressing or clamping tool 1.

Coming back to the cylinder-like plunger 9, this has at the upper end of a slot 29 in which a pressure lever 37 engages via a pin 39, its operation will be discussed again later. The pressing or pressure lever 37 in turn is connected via a deflection lever 35 with the piston 33, which is arranged in the pressure cylinder 31. Pressure cylinder 31 and pressure piston 33 are driven by a hydraulic, pneumatic or electric power supply 34 for triggering or performing the actual pressing or clamping operation. The detailed representation of the feed 24 and 34 of both the drive 21 and the pressure piston 33 is omitted for reasons of clarity, but it may be compressed air, a pneumatic fluid, an electromechanical drive, etc. act.

Based on FIGS. 2 to 4 will now be discussed on the operation of the press or clamping tool or the pressing or clamping machine shown schematically. In FIG. 1 is the starting position shown for example when not operating the press machine.

To insert now a workpiece to be pressed into the insert, such as for pressing or crimping a cable with a connection shoe, the crimping or pressing tool must first be opened, which for example, by lifting the upper crimping or pressing insert 3 takes place. The lifting of this insert by means of the lever-like driver 15, which is done by means of the pressure cylinder 22, for example, by introducing compressed air upwardly pressed piston 21. By raising the lever-like driver and the cam 13 and thus the plunger 9 is driven upward. By the upward movement of the lever-like driver 15, the sensor or switch 27 is released or there is no contact with this sensor and at the same time by means of the electrical, hydraulic or pneumatic circuit 25 generates a signal to the drive of the plunger 33 in the pressure or pressure cylinder 31 to disable or block. As a consequence, no feeding of the pressing or printing cylinder 31 via the supply line 34, ie this is blocked. In other words, in the state as shown in FIG. 2 , no pressing or clamping possible and thus eliminates the risk of injury if an operator, for example, passes by hand between the two crimping dies 3 and 5. It is now important that with a deactivated or blocked drive of the plunger 33, the plunger 9 is mounted freely movable both in the open direction and in the closing direction, which by the formation of the above-mentioned elongated hole 29 and the movable therein along the length of the elongated hole pin 39th is guaranteed. The FIG. 1 shows the pin 39 at one end of the slot 29 arranged with closed crimping, while FIG. 2 the pin 39 at the opposite end of the slot 29 shows, with fully open crimping. The free displacement or the freewheel is ensured by the storage of the plunger 9 in the sliding bearing 11th

Of course, the two crimping inserts 3 and 5 must be moved closer to one another for the insertion of the workpieces or parts to be pressed FIG. 3 is shown. This takes place in the closing direction of the two crimping movements by means of the tension spring 23, which pulls the lever-like driver 15 after canceling the compressed air supply in the lever piston 22 down, which is possible by the freewheel of the plunger 9 by means of low force. The tensile force applied by the tension spring 23 is so small that even when accidentally inserting a finger or a hand between the two crimping dies 3 and 5, there is no risk of injury and thus the operating personnel can safely place the tool parts 4 to be pressed into one of the recesses 7 of the two crimping tools 3 and 5 insert. As before, in the region K between the lever-like driver 15 and the sensor 27 either no contact or only a slight touch, that no circuit takes place and thus still the electric, pneumatic or hydraulic circuit 25 does not allow operation of the pressing cylinder or plunger. Only when the in FIG. 3 schematically shown distance d between the two crimping tools 3 and 5 is exceeded and according to the pressure on the sensor 27 is increased by the lever-like driver 15, the circuit is 25 a corresponding signal from which now suspends the blocking of the hydraulic, pneumatic or electric power supply 34 of the pressure or pressing cylinder 31. However, this distance d is so small that in any case no body part can be inserted into one of the recesses 7 between the two crimping tools 3 and 5. This safety distance is usually based on the internationally recognized so-called CE standards and is less than 6 mm.

Now, the operator can trigger the actual pressing or clamping process, for example by means of a foot pedal, by the supply, for example, of compressed air of a hydraulic pressure medium or electrically activated, whereby the pressure is carried out, as shown schematically in FIG FIG. 4 shown. In FIG. 4 it can be seen clearly that in the pressure or pressure cylinder 31 of the plunger 33 has been driven forward and connected to the piston rod 32, which acts on the lever 35. The reversing lever in turn drives the pressure lever 37 down, which in turn pushes in the slot 29 sliding the cylinder plunger 9 down, which is arranged to slide freely in the slide bearings 11. Now, the pressing is done by the two crimping dies 3 and 5 are pressed against each other, whereby the inserted in the central recess 7 workpiece 4 and the workpieces such as a wire connection and a cable lug are pressed or clamped.

Since the supply 24 of the lifting cylinder 22 is deactivated, the lever-like carrier 15 rotates freely about the axis 19 and is thus also pulled down.

• 1. Das eigentliche Werkzeug beziehungsweise die Crimpeinsätze 3 und 5 werden mittels einem separaten Antrieb geöffnet, wobei gleichzeitig der Antrieb für die Verpressung oder Klemmung deaktiviert ist. Mindestens einer der Einsätze ist in Öffnungsrichtung und/oder Schliessrichtung frei verschiebbar gelagert. Dieser separate Antrieb, wie der in den Figuren als Hubzylinder 22 und Hubkolben 21 bezeichnete Antrieb kann pneumatisch oder hydraulisch betrieben werden oder selbstverständlich auch elektromechanisch.
• 2. Um nun ein oder mehrere Werkstücke für das Verpressen zwischen die Crimpeinsätze 3 und 5 einzulegen, werden diese Einsätze mittels eines weiteren Antriebes, wie beispielsweise der Spannfeder 23, gegen einander bewegt, wobei die durch den zweiten Antrieb wie die Spannfeder erzeugte Kraft derart gering ist, dass selbst bei Unachtsamkeit, wie beispielsweise das Bewegen der Hand zwischen die beiden Crimpeinsätze, keine Verletzungsgefahr besteht.
• 3. Nach Einlegen des oder der zu verpressenden oder zu klemmenden Werkstücke 4 werden die Crimpeinsätze 3 und 5 weiter gegeneinander bewegt, bis eine Sicherheitsdistanz d, wie beispielsweise 6 mm gemäss CE-Norm, erreicht oder unterschritten wird. Dieses Unterschreiten der Sicherheitsdistanz d wird mittels eines Sensor oder mittels Detektionsmittels wie den Schalter 27 erfasst, welcher beispielsweise über einen elektrischen, hydraulischen oder pneumatischen Schaltkreis die Blockierung des eigentlichen Press- oder Klemmantriebes aufhebt, womit nun die eigentliche Verpressung stattfinden kann.
• 5. Die Bedienungsperson kann nun die Verpressung beziehungsweise Klemmung des oder der Werkstücke 4 auslösen, wobei die Distanz zwischen den beiden Crimpeinsätzen 3 und 5 derart ist, dass selbst ein Finger der Bedienungsperson nicht mehr zwischen die Einsätze geraten kann.

In summary, the mode of operation of the pressing or clamping tool proposed according to the invention can be characterized as follows:

• 1. The actual tool or the crimping dies 3 and 5 are opened by means of a separate drive, wherein at the same time the drive for the pressing or clamping is deactivated. At least one of the inserts is freely displaceable in the opening direction and / or closing direction. This separate drive, such as the drive designated as lifting cylinder 22 and lifting piston 21 in the figures, can be operated pneumatically or hydraulically or of course also electromechanically.
• 2. In order to insert one or more workpieces for the compression between the crimping dies 3 and 5, these inserts are moved by means of another drive, such as the tension spring 23 against each other, wherein the force generated by the second drive as the tension spring so small is that even in carelessness, such as moving the hand between the two crimping inserts, there is no risk of injury.
• 3. After inserting the workpiece or workpieces 4 to be pressed or clamped, the crimping inserts 3 and 5 are further moved against each other until a safety distance d, such as 6 mm according to CE standard, is reached or fallen below. This falling below the safety distance d is detected by means of a sensor or by means of detection such as the switch 27, which, for example, via an electrical, hydraulic or pneumatic circuit cancels the blocking of the actual pressing or clamping drive, which now the actual compression can take place.
• 5. The operator can now trigger the compression or clamping of the workpieces 4, wherein the distance between the two crimping dies 3 and 5 is such that even a finger of the operator can no longer fall between the inserts.

The clamping or pressing tools or machines shown in the figures and the associated security elements are of course only examples, which serve to explain the present invention in more detail.

Of course, different measures can be taken to detect the safety distance d and also the transmission of signals to the actual pressing or clamping drive can be chosen differently. It is essential that at some point by means of suitable measures the safety distance d is detected, so that when this distance is exceeded in any case the pressing or clamping drive can be activated. So it is quite possible, by means of photoelectric sensors, by means of electrical switching pulses, by means of mechanical Schaltorganen, etc. to detect this safety distance value.

The drive itself can of course be chosen differently and with reference to the FIGS. 1 to 4 mentioned pneumatic or hydraulic drive is only one option. Of course, a pressing or clamping tool can also be operated, for example, electrically or electromechanically.

Also, the second and the further drive can be chosen differently, such as in that the second drive has a tension spring and the other drive is operated pneumatically, hydraulically or electromechanically. Yes, it is even possible to manually actuate both the second and the further drive, since due to the freewheel of the cylinder plunger 9 in the disabled or blocked drive for the pressing or clamping operation this is easily movable both in the opening direction and in the closing direction.

Finally, it should be additionally mentioned that the safety arrangement proposed according to the invention can be used for any pressing or clamping tools or machines and with reference to FIGS FIGS. 1 to 4 crimping tool described is only one possible example. Further examples are cable extrusion presses, sleeve pressing machines, hydraulic cable push presses, riveting, just to mention a few other applications.

Claims (10)

1. Method for protecting a user of a crimping machine comprising a sensor (27) for sensing a crimping slot, the sensor (27) being operatively linked with a drive (31, 33) for the crimping process such that for a size of the crimping slot equalling or being larger than a predetermined distance value (d) the drive (31, 33) not being activatable or the crimping process being blocked or not being feasible, wherein

   a) for not activated or blocked drive (31, 33) a stem (9) holding an upper crimping insert (3) is linked for free movement both in an opening direction as well as in a closing direction,
   characterized by

   b) an elongated hole which extends in opening and closing direction being formed in the stem (9) and a pin (39) engaging the elongated hole (29), wherein the pin (39) is connected with the drive (31, 33) for the crimping process and wherein for not activated drive the pin (39) during the opening or closing movement of at least one of the crimping inserts is freely movable in the elongated hole with respect to and along the elongated hole, wherein

   c) for the free moveability a closing movement is possible up to a distance smaller than a safety distance,

   d) the sensor senses the distance being smaller than the safety distance wherein the sensor then removes the deactivation of the drive or the blocking or unfeasibility of the crimping process providing that the crimping process might take place, and

   e) for activated drive (31, 33) the drive presses the stem (9) in the elongated hole (29) sliding in downward direction and subsequently the two crimping inserts (3, 5) are pressed against each other by the drive (31, 33),

   f) the stem (9) of the crimping machine which is movable or driven during the crimping or clamping process or an element linked with the stem comprises a marker, a pin, a cam (13) or a recess, wherein the marker, pin, cam (13) or recess or the position of the same is suitable for determining the size of the crimping slot and wherein the marker, pin, cam (13) or recess is linked with the sensor (27) for blocking or deactivating the drive (31, 33) of the crimping machine in case of the distance exceeding the predetermined value (d).
2. Method of claim 1, characterized by an opening movement of the crimping inserts (3, 5) being provided by use of a second drive (21, 22).
3. Method of claim 1 or 2, characterized by another drive means (23) being provided for driving the crimping inserts, in particular during the introduction of a work piece (4) to be crimped, in closing direction with a force dimensioned such that a part of a human body by mistake or unawareness located between the crimping inserts (3, 5) is not injured or only slightly injured.
4. Method of claim 3, characterized by the crimping inserts for not activated drive used for the crimping process is freely movable or displaceable in opening or closing direction

   a) by use of a second and/or the additional drive and/or

   b) manually.
5. Method of claim 1, characterized by

   a) the second drive cooperating or engaging the stem of the crimping machine, in particular the pin, cam or the recess of claim 1, preferably the second drive being linked with the stem by a kind of joint, and

   b) the second drive being operatively linked with the sensor (27) such that the drive of the crimping process is blocked or deactivated when exceeding the predetermined value.
6. Method of one of claims 1 and 5, characterized by a lever type means (15) or a driving element cooperating or engaging the stem (9), wherein the means (15) pivotably linked with a pivoting degree of freedom around an axis (19) is movable or pivotable by means of a hydraulic or pneumatic drive (21, 22) in order to drive the stem into an opening direction for the crimping inserts, and a sensor being provided which in the region of the means (15) or the driving element is switchable upon contact or engagement, wherein the sensor (27) is linked with the drive of the crimping machine and wherein the sensor upon contact, cooperation or engagement by the means (15) or the driving element is switched such that upon exceeding the predetermined distance value (d) the drive (31, 33) is blocked or deactivated.
7. Method of claim 6, characterized by the additional drive means cooperating with or engaging a lever type means (15) or a driving element in a closing direction of the crimping inserts for driving the stem (9) with a deactivation of the second drive into a direction closing the crimping inserts.
8. Method of one of claims 1 to 7, wherein the drive for the crimping process as well as the second and/or additional drive if present are actuatable via at least one foot pedal.
9. Method of one of claims 1 to 8, wherein the predetermined distance value is smaller than 6 mm such that the crimping process is blocked or deactivated for a distance value of the crimping slot larger than or equal to 6 mm.
10. Method of one of claims 1 to 9, wherein the drive for the crimping process as well as the second and/or the additional drive if present is pneumatically, hydraulically or electrically or manually driven.

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