EP3093079A1 - Intake device for reforming machine - Google Patents

Abstract

An intake device for a forming machine for drawing an elongated workpiece, in particular a wire or a pipe, from a workpiece supply to a forming device of the forming machine has at least one pair of feed rollers having two feed rollers (400) which are arranged with mutually parallel axes of rotation and driven in opposite directions and with profiled peripheral surfaces (410) delimiting a feed nip for passing the workpiece. Each of the feed rollers is non-rotatably and removably attached to one end of an associated feed shaft (300) by means of a roll tensioning system. The roll tensioning system has a clamping screw (500) centered on the axis of rotation of the feed roller and having a threaded portion (520) and a head portion (510) which is wider in relation to the threaded portion. In the clamping screw a head-side open recess (530) is formed with a non-round driving profile for insertion of a clamping tool.

Description

The invention relates to a drawing-in device for a forming machine for drawing in an elongate workpiece, in particular a wire or a tube, from a workpiece supply to a forming device of the forming machine and to a forming machine with such a drawing-in device.

Forming machines are machine tools that can produce smaller or larger series of molded parts with partially complex geometry mainly by forming using suitable tools made of elongated semi-finished products such as wire, tube, strip or the like in an automatic manufacturing process. A forming machine can be, for example, a bending machine for producing two-dimensionally or three-dimensionally bent bent parts of wire material, strip material or tube material by bending or a spring manufacturing machine for producing compression springs, tension springs, leg springs or other spring-like shaped parts by spring winds or spring coils.

For the efficient production of large numbers of molded parts today highly productive computer numerically controlled, multi-axis forming machines are used. Such a forming machine has a plurality of controllable machine axes, a drive system with a plurality of electrical drives for driving the machine axes, and a control device for the coordinated control of working movements of the machine axes in a manufacturing process according to a computer-readable control program specific to the manufacturing process.

In the production of coil springs or other shaped wire parts, the wire (spring wire) is fed or fed under control of an NC control program by means of a drawing-in device of the forming machine from a workpiece supply (eg, reel) to a forming device of the forming machine. By means of the downstream in the material conveying direction forming device of the supplied wire is transformed by means of tools of the forming device to form a coil spring or other molded part. Upon completion of a forming operation, the finished molded article is separated from the supplied wire under the control of the NC control program by means of a cutter. This process repeats cyclically for each molded part to be manufactured.

A retraction device of the type considered here has at least one pair of feed rollers, which has two feed rollers, which are arranged with mutually parallel axes of rotation and can be driven in opposite directions rotating. The feed rollers define with their profiled peripheral surfaces a nip for passing the workpiece (e.g., wire or pipe). By controlling the rotational speed and direction of rotation of the feed rollers thus the feed rate and feed direction of the material to be processed can be specified.

The feed rollers should ensure as slip-free as possible transport of the material through the feed nip and should therefore attack with high clamping force, but still gently friction on the material to be delivered. Each of the feed rollers is fixed by means of a roll tensioning system at the free end of an associated feed shaft. The feed shaft is coupled to a drive and transmits the driving forces to the feed rollers. The connection between the input shaft and feed roller should be rotationally fixed in order to implement the rotation of the feed shaft without play in a conveying movement can. Since the feed rollers are machine elements dependent on the geometry of the processed workpiece, they should be relatively easy to replace by a machine operator.

The retraction device is usually arranged relatively close to the region of the forming tools of the forming device. The space in the immediate vicinity of the forming device is often required in modern forming machines to attach additional components, e.g. a camera to observe the processes during forming. The collection device should therefore take as little space as possible in areas that are well suited for the attachment of additional components.

TASK AND SOLUTION

The invention has for its object to provide a retraction device of the type mentioned above, which allows for safe operation a quick change of feed rollers and further claimed little space in addition to the feed rollers.

This object is achieved by a retraction device with the features of claim 1 and by a forming machine with the features of claim 15. Advantageous developments are specified in the dependent claims. The wording of all claims is incorporated herein by reference.

According to the claimed invention, the roll tensioning system has a clamping screw centered on the axis of rotation of the draw-in roll and having a threaded portion and a head portion which is wider than the threaded portion. The clamping screw has a head-side open recess with a non-round driving profile for inserting a clamping tool.

The threaded section should fit into an end-face internal thread of the draw-in shaft in order to screw the clamping screw into the draw-in shaft. The offset axially to the threaded portion head portion is used to tighten the feed roller to the feed shaft.

The clamping screw, which is also referred to in this application as a central clamping screw, may be the only operator-operated clamping element of the connection between the feed shaft and feed roller. Further, separately operated clamping elements are not necessary and preferably not provided. For the operator, it may therefore be sufficient to replace a feed roller to release only the clamping screw to replace the feed roller against another feed roller and fasten the clamping screw or tighten. As a result, the change of feed rollers is greatly simplified and requires little time. For tightening and loosening the clamping screw only a clamping tool is required, which has a portion which fits into the head-side open recess and has a non-round driving profile, which fits the non-round driving profile of the recess.

Since the rotational connection between clamping screw and clamping tool on the head-side open recess, the head portion can be optimized in shape for its other functions. In particular, the head portion may be relatively flat, since the reliability of the rotational connection between clamping tool and clamping screw on the shape and depth of the recess can be optimized with non-round driving profile. In particular, it is for example possible that the head portion of the clamping screw is limited by a circular cylindrical peripheral surface, so that the head portion can be made rotationally symmetrical except for the region of the recess. As a result, a particularly uniform distribution of clamping forces when tightening the clamping screw can be achieved.

The recess is formed in preferred embodiments as a hexagon socket recess. This makes it possible to achieve very high torques or torques when tightening the clamping screw by means of commercially available clamping tools with external hexagonal cross-section. Other out of round driving profiles are also possible.

For example, the open recess may have an inner square profile, an inner square profile, an inner multi-tooth profile or a slot profile, optionally with crossed slots.

The head-side open recess may be so deep that it projects into the region of the threaded portion. As a result, a reliable transmission of large torques is favored.

According to a further development, it is provided that the recess is formed as a passage recess passing axially through the clamping screw. In this way, on the one hand, a sufficient depth of the recess can be achieved in order to obtain sufficient force transmission surfaces on the driving profile. Furthermore, an immediate access to the central region of the free end of the feed shaft is created by the continuous passage recess. In many collection devices there sits a grease nipple, which serves to supply the lubrication points of the intake shaft with lubricant. The introduction of lubricant through the grease nipple can thus be done with tightened clamping screw.

According to one embodiment, the clamping screw is designed as a flat-head clamping screw, in which a (measured parallel to the axis of the clamping screw) height of the head portion is smaller than a diameter of the threaded portion. Such a flat head section requires only relatively little space on the side facing away from the feed shaft of the feed roller, so that if necessary, for example, brought a camera or other accessory relatively close to the feed roller and mounted there. This provides, inter alia, the possibility of monitoring their production via a measuring system with camera even with very short springs and possibly controlling it based on measurement results of the camera system. In some embodiments, the height of the head portion is less than 50% of the diameter of the threaded portion, whereby the overall shape of the flat head tensioning screw differs significantly from many provided for other purposes clamping screws.

The design as a flat-head clamping screw is particularly possible because the clamping screw has the head-side open recess, which is sufficient for applying a clamping tool.

In some embodiments, a (maximum) diameter of the head portion is at least twice the diameter of the threaded portion. The head portion can thus be relatively wide or expanded in area compared to its height. If required, such a broad head section can be directly clamped, ie in particular without Interposed layer of a washer or the like, rest on the outside of the feed roller and thereby transfer clamping forces on this.

The inner side of the head section facing the threaded section can be flat, so that it can bear on a likewise flat outer side of a feed roller over a large area. However, it has been found that it can be advantageous if on the inside of the head portion a radially inner flat recess is provided such that on the inside of the head portion on the outer edge of the head portion encircling, projecting in the direction of the threaded portion support ring is formed. It can thereby be achieved that when tightening the clamping screw, the clamping force is transmitted exclusively via contact surfaces in the region of the radially outer bearing ring, whereby a particularly reliable transmission of the torque or a particularly reliable entrainment is supported.

The support ring can be closed in the circumferential direction, but this is not mandatory. It may consist of one or more ring segments, between which there is a gap in the circumferential direction. In general, a plurality of relatively small-area bearing surfaces or bearing zones can be formed distributed over the circumference, e.g. exactly three contact surfaces. As a result, the force distribution can be influenced if necessary.

Some embodiments are characterized by a washer, which is arranged in the assembled state of the feed roller at least with an inner portion between the head portion of the clamping screw and the head portion facing side surface or outer surface of the feed roller. Using a washer, it is possible to distribute the clamping force generated by the clamping screw on a large area, which can be achieved a better frictional engagement between the clamping screw and feed roller.

The washer can be closed in the circumferential direction, similar to conventional washers, ie have only an inner passage opening for passing the threaded section. Particularly advantageous is a variant of the washer, in which this has a through hole for passing the threaded portion, wherein the passage opening merges on one side in a radially continuous side opening whose inside diameter (measured tangential to the circumferential direction) is greater than an outer diameter of the threaded portion and smaller than is a maximum diameter of the head section. Such a washer can be used or removed without the clamping screw must be completely unscrewed from the feed roller. The clamping screw can thus remain in partially screwed state.

On one of the feed roller facing the inside of the washer, a radially inner recess may be provided such that on the inside of a circumferential outer edge of the washer, projecting support ring is formed. The support ring can be continuous in the circumferential direction. Instead, a plurality of circumferentially spaced ring segments or bearing zones may be formed in order to obtain spatially limited contact areas at specific locations. In one variant, exactly three bearing surfaces or bearing zones are present, which effect a three-point bearing.

By providing support surfaces (one or more) only at the outer edge of the washer, the area of frictional engagement between the washer and the feed roller with respect to the common axis of rotation is moved radially outward, whereby a better torque transfer between clamping screw / washer and feed roller can be achieved.

The washer may have a circular or circular outer contour. However, this is not mandatory. Other shapes of the outer contour are possible, e.g. polygonal shapes such as triangle, square or hexagon, possibly with rounded corners.

When using a washer (laterally open or closed), it is not necessary that the head portion can transmit force directly to the outside of the feed roller. The head section can therefore be chosen relatively small in diameter. In some embodiments, the draw-in shaft has a shaft collar and an adjoining frontal extension for attachment of a feed roller and the feed roller has a central through-hole whose inner diameter is greater than an outer diameter of the extension. When mounting the feed roller this can be plugged onto the extension and advanced to rest on the shaft collar, the extension then engages in the passage opening. The outer diameter of the head portion of the clamping screw may be smaller than the inner diameter of the through hole, so that the roller can be removed without completely loosening the clamping screw.

This dimensioning of the head portion is particularly advantageous in conjunction with a laterally open washer, since in this case, the clamping screw only needs to be solved for replacing a feed roller, but not completely unscrewed. When loosening the clamping screw, the washer can then be removed laterally and the feed roller over the head portion of the screw are pulled outwards. The assembly of another feed roller is then reversed by first the feed roller over the head section the screw is pushed onto the extension before laterally inserting the washer and then tightening the clamping screw.

The clamping screw ensures a frictional connection between the feed shaft and feed roller, with some of the above special measures can help to improve the frictional connection, so that a relative rotation between the feed shaft and feed roller is avoided or greatly impeded.

In some processes, the feed rollers are subjected to strong accelerations (increase in the rotational speed) or braking movements (reduction of the rotational speed), possibly in frequent change, so that it can not be ruled out that an exclusively non-positive connection slowly loosens. In many embodiments, therefore, additional measures for producing a force acting in the circumferential direction positive connection between feed shaft and feed roller are provided.

In some embodiments, the draw-in shaft has a shaft collar with an end abutment surface for applying the feed roller, wherein on the shaft collar at least one projecting beyond the contact surface eccentric to the axis of rotation seated driving pin is mounted, which is dimensioned for insertion into an eccentric driving bore of the feed roller. In some embodiments, a plurality of driving bolts are provided, in particular three driving pins distributed in uniform angular pitch around the central axis. In order to facilitate the assembly and disassembly of the feed roller, it is usually provided that a driving pin relative to the associated driving bore has a slight undersize in the way that the outer diameter of the driving pin is slightly smaller than the inner diameter of the driving bore, so that a small game remains in the radial direction.

In order to achieve a reliable positive engagement between feed shaft and feed roller under these conditions, a clearance compensation device is provided in some embodiments, which can be operated by tightening the clamping screw in such a way that when tightening the clamping screw between the driving pin and the driving hole existing game eliminated becomes. Thus, a positive connection in the circumferential direction can be created, so that a gradual release after repeated acceleration and deceleration is avoided.

The lash adjuster is operated by tightening the clamping screw, so does not require separate from the clamping screw actuators. In some embodiments This is achieved in that the play compensation device arranged on the driving pin and radially expandable by the action of an axial force clearance compensation element, wherein the play compensation device is dimensioned so that in a relaxed state of the play compensation device (ie, for example, unscrewed or partially dissolved clamping screw) at the Shaft collar adjacent feed roller an actuating portion of the lash adjuster protrudes beyond the shaft collar side surface of the feed roller. Then, the tightening screw is tightened and thereby brought into a tensioned state, so presses the head portion of the clamping screw (or lying between the head portion and feed roller washer) on the actuating portion and exerts the axial force on the lash adjuster from which is radially spread in response and eliminates the play between driving pin and driving bore.

In one embodiment, a structurally simple and yet effective clearance compensation device is provided in that a resiliently compressible mold element is used as a clearance compensation element, which is compressed via an outer actuating sleeve when the clamping screw is tightened. The molding element may e.g. an O-ring made of an elastically compressible elastomer.

The invention also relates to a forming machine which has a forming device with one or more forming tools and a drawing-in device for drawing in an elongated workpiece, in particular a wire or tube, from a supply of material into the region of the forming device. The drawing-in device is a drawing-in device of the type described in this application. The forming machine may in particular be a spring-making machine or another wire-processing machine or a tube-bending machine.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1

zeigt einige Elemente einer CNC-Federwindemaschine gemäß einer Ausführungsform der Erfindung;

Fig. 2

zeigt eine schräg perspektivische Darstellung mit Elementen der Umformeinrichtung der Federmaschine und einer vorgeschalteten Einzugseinrichtung;

Fig. 3

zeigt einen Längsschnitt durch eine Einzugswelle und eine darauf montierte Einzugswalze gemäß einem Ausführungsbeispiel;

Fig. 4

zeigt eine vergrößerte Detaildarstellung einer Spielausgleichseinrichtung beim Ausführungsbeispiel von Fig. 3;

Fig. 5

zeigt eine axiale Ansicht der Anordnung aus Fig. 3;

Fig. 6

zeigt einen Längsschnitt durch eine Einzugswelle und eine darauf montierte Einzugswalze gemäß einem anderen Ausführungsbeispiel;

Fig. 7

zeigt eine axiale Draufsicht des Ausführungsbeispiels aus Fig. 6;

Fig. 8

zeigt eine schräg perspektivische Ansicht einer Unterlegscheibe des Ausführungsbeispiels aus Fig. 6;

Fig. 9

zeigt eine schräg perspektivische Ansicht der zentralen Spannschraube des Ausführungsbeispiels aus Fig. 6;

Fig. 10

zeigt eine Variante einer Unterlegscheibe mit dreieckförmiger Gestalt ; und

Fig. 11

zeigt in Fig. 11A eine Draufsicht auf eine und in Fig. 11B einen Schnitt durch eine einer Unterlegscheibe mit drei Auflagezonen am äußeren Rand.

Further advantages and aspects of the invention will become apparent from the claims and from the following description of preferred embodiments of the invention, which are explained below with reference to the figures.

Fig. 1

shows some elements of a CNC spring coiling machine according to an embodiment of the invention;

Fig. 2

shows an oblique perspective view with elements of the forming device of the spring machine and an upstream retraction device;

Fig. 3

shows a longitudinal section through a feed shaft and a feed roller mounted thereon according to an embodiment;

Fig. 4

shows an enlarged detail of a lash adjuster in the embodiment of Fig. 3 ;

Fig. 5

shows an axial view of the arrangement Fig. 3 ;

Fig. 6

shows a longitudinal section through a feed shaft and a feed roller mounted thereon according to another embodiment;

Fig. 7

shows an axial plan view of the embodiment Fig. 6 ;

Fig. 8

shows a diagonal perspective view of a washer of the embodiment Fig. 6 ;

Fig. 9

shows a diagonal perspective view of the central clamping screw of the embodiment Fig. 6 ;

Fig. 10

shows a variant of a washer with a triangular shape; and

Fig. 11

shows in Fig. 11A a plan view of one and in Fig. 11B a section through a washer with three support zones on the outer edge.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The schematic overview in FIG Fig. 1 shows elements of a forming machine in the form of a CNC spring coiling machine 100 according to one embodiment. The spring coiling machine 100 has a retraction device 110 which feeds successive wire sections of a wire 115 and guided by a straightening unit wire 115 with numerically controlled feed rate profile in the region of a forming device 120. The wire is converted into a helical spring F by means of numerically controlled tools of the forming device.

The tools include u.a. two angularly offset by 90 ° wind pins 122, 124 which are adjustable in position and determine the diameter of the spring produced. A pitch tool 130 has a tip oriented substantially perpendicular to the spring axis which engages the turns of the developing spring. Thus, the slope of the turns can be specified. Above the spring, a numerically controllable cutting tool 150 is mounted, which separates the produced coil spring with a vertical working movement of the supplied wire supply after completion of the forming operations. A severing tool may also be located below the spring, e.g. for springs with different winding sense.

The machine axes of the CNC machine belonging to the tools are controlled by a computer numerical control device 180, which has memory devices in which the control software resides, to which i.a. an NC control program for the working movements of the machine axes heard.

To produce a helical spring, the wire is advanced starting from the position shown by means of the retraction device 110 in the direction of the wind pins 122, 124 and deflected by the wind pins to the desired diameter to form a circular arc curvature until the free wire end reaches the pitch tool 130. Upon further wire feed, the axial position of the pitch tool determines the current local pitch of the developing coil spring. The pitch tool is axially displaced under control of the NC control program when the slope is to be changed during spring development. The adjusting movements of the pitch tool essentially determine the gradient along the helical spring.

As Fig. 2 shows, the spring coiling machine is equipped with a camera-based, optical measuring system for the non-contact, real-time acquisition of data on the geometry of a currently produced spring. The measuring system has a CCD-camera 250 mounted on a machine-fixed carrier, which can supply two-dimensional images to a connected image processing system via an interface. The software for image processing is housed in a program module, which cooperates with the control device 180 of the spring coiling machine or is integrated in this.

The camera is attached to the side of a wire guide device in the area immediately in front of the retraction device 110 and can be adjusted in position. The machine-near camera 250 is mounted so that its rectangular image field forms part of the developing image Capture spring immediately after leaving the forming tools to determine the spring geometry generated.

The intake device 110 ensures the wire feed with a predefined feed rate profile. In this case, the collection device pulls the wire from a wire supply, such as a reel, gradually and leads the wire to the forming tools of the forming device. The intake device has two feed roller pairs 112 and 114 connected in series in the direction of passage of the workpiece. Each of the intake roller pairs has two intake rollers, which are arranged with horizontal axes of rotation parallel to each other. The feed rollers are driven in opposite directions by means of a drive to achieve the conveying movement. The feed rollers have profiled circumferential surfaces with circumferential grooves in the circumferential direction, whose shape and size is adapted to the cross section of each workpiece to be conveyed. With the peripheral surfaces, the feed rollers of a pair of feed rollers limit a pull-in gap through which the workpiece is passed.

Each of the feed rollers sits at the free end of a feed shaft, which is rotatably mounted with horizontal axis of rotation in the machine frame. Each of the feed rollers is non-rotatably and removably attached by means of a roll tensioning system at the end of the associated feed shaft. The roll tensioning system has several tasks to accomplish. On the one hand, a reliable non-rotatable attachment must be ensured so that the rotational movements of the feed shaft slip-free on the feed roller and the workpiece conveyed thereby can be transmitted. On the other hand, it should be possible for an operator to do a roll change as comfortably and quickly as possible. A roll change is necessary, for example, if the forming machine has to be converted for the use of another type of workpiece, for example a wire with a different diameter. Even if the feed rollers are worn, the work required for the replacement should take as little time as possible. Finally, the roll tensioning system should also be designed so that as little space as possible is required in the area in front of the feed rollers, for example to bring the camera 250 so close to the feed device that its detection area can already grasp the wire immediately after leaving the wire guide, so that even when producing very short springs an observation on the camera is possible.

Based on Fig. 3 to 5 Now, a first example of a roll tensioning system will be explained. The longitudinal section in Fig. 3 shows a feed shaft 300, which can be driven by means of the associated drive about an axis of rotation 310 with different directions of rotation and rotational speeds. Near the free end of the pull-in shaft is on the shaft body a Shaft 302 formed, so a diameter extension, which offers a flat contact surface 303 for a feed roller 400 at its front.

In the shaft collar, three eccentric driving pins 320, which are circumferentially offset from each other by 120.degree., Are fastened, which extend axially parallel to the axis of rotation 310 and serve for insertion into a respective driving bore 402 of the draw-in roller. Towards the free end of the draw-in shaft, an extension 304 with a cylindrical outer contour projects beyond the shaft collar 302. On the extension of the associated feed roller 400 is pushed in the axial direction until it rests against the contact surface 303 of the shaft collar 302.

At the free end of the pull-in shaft is a front-side centric blind hole 306 with internal thread 308. The flat hole bottom is at the level of the shaft collar 302. There is a central lubricating nipple 380 of a lubrication system for the pull-in shaft attached. Via the grease nipple, the rotary bearings of the intake shaft can be supplied with lubricant.

The feed shaft carries at its free end the associated feed roller 400. The feed roller 400 is pushed onto the extension 304 and is located on the free front of the shaft collar 302 at. The axial height of the extension 304 is a few tenths of a millimeter less than the (measured in the axial direction) thickness of the feed roller. The feed roller has a profiled peripheral surface 410, in which in the example two circumferential C-shaped grooves are incorporated, whose shape is adapted to the shape of the wire to be conveyed. The feed roller has three axially extending driving holes 402 whose inner diameter are adapted to the outer diameter of the associated driving pins 320, that the driving pins fit into the associated driving holes when placing the feed roller with little lateral play. Each feed roller has a central through hole 406, the inner diameter of the outer diameter of the extension 304 is adapted so that the feed roller sits largely free of play on the extension.

In the assembled configuration shown, the draw-in roller 400 is tensioned onto the pull-in shaft 300 by means of a central tightening screw 500. The clamping screw is centered to the axis of rotation 310 of the feed shaft. The tensioning bolt is the only tensioning element of the roll tensioning system that must be operated by the operator to mount or remove a feed roller from the input shaft. The clamping screw 500 has a threaded portion 520 whose external thread fits into the internal thread of the frontal recess 306 of the feed shaft. Integral with the threaded portion, a flat head portion 510 is formed, which in the assembled state with its side facing the threaded portion flat inside 512 presses on the flat outer side of the feed roller 400 and thereby the feed roller clamped against the roll collar 302. As in Fig. 5 To recognize well, the head portion has a circular cylindrical outer contour.

In the middle of the clamping screw, a recess 530 which is open at the top is formed in the form of a hexagon socket recess. The hexagon socket serves as a non-round driving profile for actuating the clamping screw by means of a correspondingly contoured clamping tool with external hexagonal profile. The recess 530 is designed as a through-passage which is continuous in the axial direction, so that access to the lubricating nipple 380 is possible through the recess, even when the clamping screw is inserted.

Since the clamping tool for clamping and releasing the clamping screw uses the central recess 530, the head section 510 need not be specially designed for applying a clamping tool. The head section can be optimally adapted to the task of bracing the feed roller with the feed shaft. In addition, the head portion may be relatively flat, so that the clamping screw may be formed as a flat-head clamping screw. This makes it possible to approach a camera or other accessory very close to the feed rollers. In the example case, the height H of the head section (measured parallel to the rotation axis 310) is many times smaller than the outside diameter of the threaded section and in the example is less than 20% of this outside diameter. On the other hand, the diameter of the head portion is significantly larger than the diameter of the threaded portion, for example, at least twice as large. As a result, a wide contact surface of the head section is secured to the feed roller. In the example, the head portion 510 extends over the driving holes 402 away, so that they are covered with mounted clamping screw from the outside (see. Fig. 5 ). As a result, not only a visually appealing solution is created (see. Fig. 5 ), but the driving holes are also protected against the ingress of dirt, etc.

In a variant which is not specifically illustrated, a radially inward flat recess 513 is formed on the inner side 512 of the head portion facing the threaded portion, which is formed such that an outer support ring 514 is formed, which runs around the outer edge of the head portion and protrudes slightly towards the threaded portion (FIG. see dashed line). Thereby, the clamping force, which is exerted by the head portion 510 on the feed roller, applied exclusively in the radially outer region of the support ring. As a result, an increase in the friction torque is achieved by defined large effective diameter between the pressed together parts in order to transmit the collection force as possible without slippage.

A corresponding flat recess 313 can also be provided on the front side or outer side of the shaft collar 302 facing the feed roller (see dashed line). This can be achieved that on the outside of the shaft collar an annular support surface is formed for the feed roller.

With clamped clamping screw 500 there is a reliable frictional connection or frictional engagement between draw-in shaft with clamping screw on the one hand and on the shaft mounted feed roller on the other. Furthermore, the driving pins 320 can ensure a positive entrainment of the feed roller. However, the bolts are provided for easier placement and removal of the feed roller against the driving bore with a slight undersize, so that theoretically the possibility of a backlash when changing the direction of rotation is given.

In the embodiment shown, a play compensation device 360 is provided in each case in the region of the connection between driving pins 320 and driving bore 402 (cf. Fig. 4 ), which is automatically actuated when tightening the clamping screw on the head portion 510 and eliminates any residual play between driving pin and driving bore.

The stud bolt 320 formed as a stud has close to the shaft collar a cylindrical first portion 312, whose outer diameter is only slightly smaller than the inner diameter of the driving bore, and an adjoining front portion 314 with a smaller diameter. On the front portion of a mold element in the form of an O-ring 362 is pushed and rests on the inner cylindrical portion 312. On the front side of an actuating sleeve 364 is placed, the secured against loss on the front portion 314 and is seated with its shaft facing the front side facing the O-ring. The length of the sleeve is dimensioned so that its sleeve head in the relaxed state (for example, not yet mounted clamping screw) protrudes slightly beyond the flat outer side 414 of the feed roller. Now, if the clamping screw is tightened, the head portion presses with the inner side facing the feed roller on the actuating sleeve 364, whereby the O-ring is axially compressed and widened radially in the manner of a spreader. As a result, in the tensioned state, any play is forced out of the connection between driving bolts and driving bore, so that this connection now acts without clearance as a form-locking connection in the circumferential direction.

In other words, when tightening the central clamping screw 500, the elastic elements are axially compressed on the driving pin. The resulting radial Expansion fills the gap between driving pin and driving bore in the feed roller and thus creates a positive connection between driving pin and feed roller, whereby a backlash on the feed roller is prevented.

There is a total of both a non-positive and positive rotational connection between feed roller and feed shaft created, this connection using a single actuator, namely the central clamping screw 500, manufactured and released.

Based on Fig. 6 to 9 Now another embodiment of a roll tensioning system will be described. The roll tensioning system can be used with the same feed shafts and the same feed rollers as the first embodiment. Therefore, these components carry the same reference numerals as in the first embodiment and with respect to their configuration, reference is made to the description there.

The roll tensioning system includes a tightening screw 600 with head portion 610, threaded portion 620, and central hexagon socket receiving aperture 630 for a tightening tool. In addition to the central clamping screw 600, a washer 700 is provided which, in the installed state of the feed roller, lies at least with an inner section 710 between the head section 610 of the clamping screw and a side surface (flat outer surface) of the feed roller facing the head section. The power flow between the clamping screw and the feed roller is guided through the washer.

As in the FIGS. 7 and 8 can be seen, the washer is not closed in the circumferential direction, but designed substantially crescent-shaped or C-shaped with a lateral opening. A through opening 725, the inner diameter of which is slightly larger than the outer diameter of the threaded portion of the clamping screw, passes over on one side into a radially continuous side opening 727. The measured between the ends of the free legs of the washer clear width 728 of this side opening is slightly larger than the outer diameter of the threaded portion of the clamping screw and in the example corresponds to twice the radius of curvature of the circular shaped part of the through hole. The inner portion 710 of the washer adjoining the throughbore is somewhat shallower than the thicker or more massive outer portion 720, which, with its inner contour when the clamping screw is mounted, directly adjoins the outer contour of the head portion.

On its inside facing the feed roller 400, the washer 700 has a flat, radially inner recess 713, so that in the outer region of the feed roller facing circumferential support ring 714 results in the area of the clamping force of the clamping screw is transferred to the feed roller.

The outer diameter of the washer can be chosen so that there is a sufficiently large contact surface for transmitting a frictional engagement or a large radial distance of the support ring to the center, in order to effect an effective frictional engagement. Since using a washer, the head portion 610 of the clamping screw 600 is no longer required for direct power transmission to the feed roller, the diameter of the head portion may be substantially smaller than in the other embodiment. As in Fig. 6 can be clearly seen, the outer diameter D of the head portion 610 is slightly smaller than the inner diameter of the central through hole 406 of the feed roller. This makes it possible to set up or remove the feed roller without completely loosening the clamping screw 600 and remove it from the internal thread of the feed shaft.

When removing the feed roller, starting from the in Fig. 6 shown assembled configuration as follows. First, the tightening screw 600 is loosened a little by means of an external hexagon clamping tool, so that the washer 700 is relieved. Then, the washer can be removed laterally, which is possible due to the side opening of the washer. Then, the feed roller can be withdrawn substantially in the axial direction, over the head portion of the partially screwed clamping screw away. So the tensioning screw does not have to be completely loosened to make a roll change. When mounting a new feed roller is reversed procedure by first the feed roller over the head portion of the clamping screw on the extension 304 is pushed, then the washer is pushed laterally and finally the clamping screw is tightened by the clamping tool again, in which case the clamping force on the Washer is transferred to the feed roller.

There are many variants possible. Fig. 10 shows an example of a variant of a washer 1000 with a substantially triangular shape of the outer contour with rounded corners. As with the variant of Fig. 6 to 8 a lateral passage opening is provided, so that the washer can be inserted or removed with screwed clamping screw.

Fig. 11 shows in Fig. 11A a plan view of one and in Fig. 11B a section through a washer 1100. As in the variant off Fig. 6 to 8 a flat, radially inner recess 1113 is formed on the inner side of the washer 1100 facing the feed roller, so that a bearing ring facing the feed roller results in the outer region, in the region of which the clamping force of the clamping screw is transferred to the feed roller. The support ring is interrupted in the circumferential direction, so that three circumferentially offset ring segments or support zones 1114-1, 1114-2 and 1114-3 are formed.

Claims (15)

Feeding device (110) for a forming machine (100) for drawing in an elongated workpiece, in particular a wire or a tube, from a workpiece supply to a forming device (120) of the forming machine
at least one feed roller pair (112, 114), which has two feed rollers (400) which are arranged with mutually parallel axes of rotation and are driven in opposite directions and with profiled peripheral surfaces (410) delimiting a feed nip for passing the workpiece (115),
wherein each of the draw-in rollers is non-rotatably and interchangeably fixed at one end of an associated draw-in shaft (300) by means of a roll tensioning system,
characterized in that
the roll tensioning system has a tightening screw (500, 600) centered on the rotation axis of the draw-in roll and having a threaded portion (520, 620) and a head portion (510, 610) which is wider than the threaded portion,
wherein in the clamping screw, a head-side open recess (530, 630) is formed with a non-round driving profile for insertion of a clamping tool. Retractable device according to claim 1, characterized in that the recess (530, 630) is designed as a hexagon socket recess. Retractable device according to claim 1 or 2, characterized in that the recess (530, 630) is formed as an axially passing through the clamping screw through-recess. Retractable device according to one of the preceding claims, characterized in that the clamping screw (500, 600) is designed as a flat-head clamping screw, wherein a height (H) of the head portion (510, 610) is smaller than a diameter of the threaded portion, preferably the Height of the head portion is less than 50% of the diameter of the threaded portion. Retractable device according to one of the preceding claims, characterized in that a diameter of the head portion (510) of the clamping screw (500) is at least twice as large as the diameter of the threaded portion (520). Feeding device according to one of the preceding claims, characterized in that on an inner side (512) of the head section facing the threaded section the clamping screw a radially inner recess (513) is provided such that on the inside at the outer edge of the head portion a circumferential, the threaded portion projecting support ring (514) is formed or a plurality of circumferentially spaced, projecting to the threaded portion support zones are formed. Retractable device according to one of the preceding claims, characterized by a washer (700, 1000, 1100), which in the installed state of the feed roller at least with an inner portion (710) between the head portion (610) of the clamping screw (600) and a side surface facing the head portion the feed roller is arranged. Feeding device according to claim 7, characterized in that the washer (700, 1000, 1100) has a passage opening (725) for passing the threaded portion, wherein the passage opening merges on one side in a radially continuous side opening (727) whose clear width (728 ) is larger than an outer diameter of the threaded portion (620) and smaller than a maximum diameter of the head portion (610). Feeding device according to claim 7 or 8, characterized in that on one of the feed roller facing the inside of the washer (700, 1100) has a radially inner recess (713, 1113) is provided such that on the inside at the outer edge of the washer, a circumferential, projecting Support ring (714) is formed or a plurality of circumferentially spaced, the threaded portion projecting support zones (1114-1, 1114-2, 1114-3) are formed. Feeding device according to one of claims 7 to 9, characterized in that the feed shaft has a shaft collar (302) and an adjoining end projection (304) for attachment of a feed roller (400) and that the feed roller has a central through-bore (406) whose Inner diameter is larger than an outer diameter of the extension, wherein an outer diameter of the head portion (610) is smaller than the inner diameter of the through hole (406). Retractable device according to one of claims 7 to 10, characterized in that the washer (700, 1100) has a circular or circular arc-shaped outer contour or that the washer (1000) has a shape deviating from the circular arc shape of the outer contour, in particular a polygonal shape, preferably a triangle , Square or hexagon, preferably with rounded corners. Feeding device according to one of the preceding claims, characterized in that the draw-in shaft (300) has a shaft collar (302) with a front-side abutment surface for applying the draw-in roller (400), wherein the shaft collar at least one projecting beyond the contact surface driving pin (320) is mounted , which is dimensioned for insertion into a driving bore (402) of the feed roller. Retractable device according to claim 12, characterized by a play compensation device (360) which can be actuated by tightening the clamping screw such that when tightening the clamping screw between the driving pin and the driving bore existing game is eliminated, preferably the play compensation device (360) on the driving pin ( 320) arranged and by the action of an axial force radially expandable clearance compensation element (362) and the clearance compensation device is dimensioned so that in a relaxed state of the lash adjuster abutting the shaft collar feed roller (400) an actuating portion of the lash adjuster the side facing away from the shaft surface (414 ) of the feed roller dominates. Feeding device according to one of the preceding claims, characterized in that the draw-in shaft (300) has a shaft collar (302) with a front-side abutment surface for applying the draw-in roller (400), wherein on the feed roller facing the outside of the shaft collar (302) has a shallow recess (302). 313) is provided such that on the outside of the shaft collar an annular support surface is formed for the feed roller. Forming machine (100) for producing molded parts from an elongated workpiece (115), in particular from a wire or tube, comprising: a forming device (120) with one or more forming tools, and a retraction device (110) for drawing an elongated workpiece from a supply of material into the region of the forming device (120); characterized in that the retraction device (110) is designed according to one of the preceding claims.

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