DE102013207028B3 - Spring coiling machine with adjustable cutting device - Google Patents

Abstract

A spring coiling machine for producing helical springs (200) by spring coils has a feed device for feeding wire (115) to a forming device (120), the forming device having at least one winding tool (122, 124) and at least one pitch tool (130), as well as one Cutting device for separating a completed coil spring from the supplied wire after a forming operation has been completed. The cutting device has a cutting tool (152) which can be moved along a predeterminable closed path curve by means of a cutting tool drive system. A control device is used to control the feed device, the forming device and the cutting device based on an NC control program. The spring coiling machine has a programmable path curve setting system for setting the shape and / or position of the path curve to be traversed by the cutting tool. With the help of this path curve setting system, you can choose between a straight path curve, an elliptical or egg-shaped path curve (BK1) with a preselectable height-to-width ratio, or an asymmetrical path curve (BK3) with a non-mirror-symmetrical one that deviates from an elliptical shape or egg shape History can be set.

Description

BACKGROUND

The invention relates to a spring coiling machine for producing coil springs by spring winds according to the preamble of claim 1.

Coil springs are machine elements that are required in numerous applications in large numbers and different designs. Coil springs, which are also referred to as twisted torsion springs, are usually made of spring wire and designed depending on the load in use as tension springs or compression springs. Compression springs, in particular suspension springs, are needed for example in large quantities in the automotive industry.

Coil springs are nowadays commonly manufactured by spring winches using numerically controlled spring coiling machines. In this case, a wire (spring wire) is supplied under the control of an NC control program by means of a feeder a forming device of the spring coiling machine and formed by means of tools of the forming device to form a coil spring. The tools typically include one or more wind pins that are adjustable in position to define and, if necessary, alter the diameter of spring coils and one or more pitch tools that determine the local pitch of the spring coils at each stage of the manufacturing process. Upon completion of a forming operation, a finished coil spring is separated from the supplied wire under the control of the NC control program by means of a cutter.

In the manufacture of springs often the type of cut is of great importance, as it determines certain properties of the finished coil spring. In general, three types of cutting methods are distinguished, namely the so-called "straight cut", the "rotary cut" and the "twist cut". When cutting straight, a cutting tool performs a linear linear cutting motion when cutting the wire. In the rotary cut, the cutting edge of the cutting tool is guided along a substantially elliptical trajectory to separate the wire. In torsional cutting, the wire is mechanically loaded so that it can be separated by a torsional stress. By torsion cut you can get a burr-free cut. In the other two types of cut, burrs are usually produced at the cut surface, which in some cases must be eliminated by brushing, blasting or grinding prior to further use of the coil springs.

The European patent application EP 0 804 979 A1 describes components of a cutting device for a spring coiling machine, which allow the cutting device to be changed over to optionally perform a straight cut or a rotary cut, in which the cutting tool is guided along a teardrop-shaped trajectory.

The cutting tool is held in a carriage, which is guided linearly movable in a linear guide. The linear guide is pivotally mounted. A drive motor is coupled via a drive shaft, an eccentric and a connecting rod with the carriage and can thereby cause the linear reciprocation of the cutting tool. The pivoting movement of the linear guide can be effected via a second drive shaft, which acts via an eccentric on the linear guide. The drive motor may optionally be disengaged from the second drive shaft or engaged with the second drive shaft. If no drive connection is set, then the cutting device performs a straight cut. When the second drive shaft is coupled to the drive motor, the linear guide executes a pendulum pivoting movement, resulting in a drop-shaped trajectory of the cutting tool from the superimposition of the linear linear motion and the pivoting movement.

The patent US 7,055,356 B2 describes components of a cutting device for a spring manufacturing machine constructed so that the cutting tool can be moved along a substantially elliptical trajectory. The shape of the trajectory can be changed by manually shifting the position of a slider along a linear guide.

The Japanese patent application with publication number JP 2001-293533 A shows components of a cutting device of a spring manufacturing machine. On the front wall of the machine, a vertically movable linear slide is mounted, which can be moved by means of a drive motor via a drive shaft, an eccentric and a connecting rod up and down. The carriage carries on its front side a pivotable element which carries the cutting tool. Another drive motor generates via a drive shaft and a universal joint with axial length compensation, a pivoting movement of this pivoting element about a pivot axis which is mounted in the slide in the carriage. About another shaft with a universal joint, the position of the pivot member can be changed on the carriage to change the position of the cutting tool in Federachsrichtung.

TASK AND SOLUTION

The invention has for its object to provide a flexible, user-friendly spring coiling machine, which can produce coil springs with high productivity, which are optimized in terms of sectional view, location of the cutting flash and other spring parameters according to their specification.

To solve this problem, the invention provides a spring coiling machine with the features of claim 1 ready. Advantageous developments are specified in the dependent claims. The wording of all claims is incorporated herein by reference.

The spring coiling machine according to the claimed invention has a programmable trajectory adjustment system for adjusting the shape and / or position of the trajectory to be traversed by the cutting tool. The trajectory adjustment system makes it possible to flexibly and easily set different cutting types. Optionally, a rectilinear trajectory (for a straight cut), an elliptical or egg-shaped trajectory mirror-symmetrical to a plane of symmetry with a predeterminable height-to-width ratio, or an asymmetrical, i. Non-mirror-symmetric trajectory be set with a deviating from an ellipse shape or egg shape course. These settings include, depending on the application, inter alia, an extension of the range of application of the straight section or a rotation section, an optimization of unit performance (machine output), an optimization of the sectional image of the finished coil spring, optimizing the position of the cutting burr on the finished coil spring and / or one Increase the service life of the cutting tools, especially when straight cutting, achievable.

The claimed invention utilizes a programmable trajectory adjustment system which allows an operator to specify a wide range of trajectory trajectories for the cutting tool without manual intervention on the mechanical components of the cutting device and to program these solely by control intervention.

In preferred embodiments, the adjustment possibilities are made possible by the cutting tool drive system having a first drive controllable by the control device for generating a first movement of the cutting tool and a second drive controllable by the control device independently of the first drive for generating a second movement superimposed on the first movement of the cutting tool. Different components of the cutting motion can be adjusted in almost any proportions to each other.

Preferably, the first movement is a linear linear movement along a first direction and the second movement is a linear motion superimposed pivotal movement transverse to the first direction. It would also be possible to superpose two rectilinear linear movements in mutually perpendicular directions.

In one variant, the cutting tool is mounted on a carriage which is linearly reciprocable along a linear guide in a first direction, and the linear guide is fixed to a pivot member which is pivotable about a pivot axis perpendicular to the first direction, the first one pivoting Drive with the carriage and the second drive is coupled to the pivot element. As a result, a particularly rigid arrangement is given, which only generates relatively low tilting moments, even with strong cutting forces. It would also be possible to attach a pivoting element on a linearly movable carriage.

The possibility of making the shape and / or position of the cutting path (trajectory of the cutting tool) exclusively via settings for the electric drives is used in a variant of the spring coiling machine, manually when programming the trajectory in a teach process one, two, three or To approach more edge points or interference contours and thereby lay the trajectory so that the trajectory always remains within these Störkonturen in later operation and no collisions can occur, for example, with wind tool or pitch tool. For this purpose, the control device is configured for a teach-in programming. The configuration is preferably such that, in a programming configuration, the cutting tool is manually positionable to one or more positions around a desired trajectory, the coordinates of the positions can be stored in a memory of the controller, the trajectory is calculable using the coordinates, and the cutting tool is an operating configuration under the control of the control means along the trajectory is movable. Usually, the approached positions are interference points, which are defined as points which must not exceed the trajectory.

In one variant, the spring coiling machine is equipped with a camera system which captures with its image field the area of the forming tools substantially from the front, ie parallel to the direction of the desired spring axis. From the captured images can with the means of Image processing the position of the interference contours are determined. This definition can be manual, semi-automatic or fully automatic. As a result, a "virtual teaching process" is possible in which the machine axes or the tools, in particular the cutting tool, do not have to be moved. Also in this case, the controller is configured for teach-in programming.

These and other features will become apparent from the claims but also from the description and drawings, wherein the individual features each alone or more in the form of sub-combinations in an embodiment of the invention and in other fields be realized and advantageous and protectable Can represent versions.

BRIEF DESCRIPTION OF THE DRAWINGS

1 shows a schematic overview of an embodiment of a spring coiling machine;

2 and 3 show enlarged views of components of the forming device and various adjustable trajectories for the cutting tool;

4 to 6 schematically show various views of components of the cutting device 1 ;

7 shows a view of a graphical user interface that assists the user in setting the trajectory;

8th shows in 8A to 8E schematically different types of cuts; and

9 shows a plan view of components of another embodiment of a cutting device.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The schematic overview in FIG 1 shows some constructive elements of a CNC spring coiling machine 100 according to an embodiment of the invention. The 2 to 6 show details.

The spring winding machine 100 has one with feed rollers 112 equipped feeder 110 , the successive wire sections of one coming from a wire supply and by a straightening unit 114 guided wire 115 with numerically controlled feed rate profile in the horizontal direction in the area of a forming device 120 can supply. Components of the forming devices are in the 2 and 3 clearly visible. The wire is discharged through a wire guide 116 guided. The feeder can also be referred to as a feeder, according to the wire feed can also be referred to as wire feed and the feed rate as the feed speed.

The wire is made by means of numerically controlled tools of the forming device 120 transformed into a helical spring. The tools include two wind pins arranged angularly offset by 90 ° 122 . 124 extending radially to the central axis 118 or are aligned to the position of the desired spring axis and are intended to determine the diameter of the coil spring. The position of the wind pens can be changed to the default setting for the spring diameter when setting along oblique directions as well as in the horizontal direction to set up the machine for different spring diameters. These movements can be carried out with the aid of suitable electric drives under the control of the numerical control.

A gradient tool 130 has a substantially perpendicular to the spring axis aligned tip, which engages adjacent to the turns of the developing spring. The pitch tool is parallel to the axis by means of a numerically controlled adjustment drive of the corresponding machine axis 118 the developing spring (ie perpendicular to the plane of the drawing) movable. This is therefore also referred to in this application as "slope parallel". The advanced during manufacture of the spring wire is pushed by the pitch tool according to the position of the pitch tool in the direction parallel to the spring axis, wherein the position of the pitch tool, the local slope of the spring is determined in the appropriate section. Gradient changes are effected by axis-parallel process of the pitch tool during spring production.

The forming device may have another, from below vertically deliverable pitch tool with a wedge-shaped tool tip, which is introduced when using this pitch tool between adjacent turns. The adjustment movements of this pitch tool are perpendicular to the axis 118 , This is therefore referred to in this application as "vertical pitch". The pitch tools can be brought into engagement as needed. Typically, only one of the pitch tools is engaged in a given spring coil process.

Above the spring axis is a numerically controllable cutting device 150 with a cutting equipment 152 attached, which separates after completion of a forming operation, the produced coil spring with a defined working movement of the supplied wire supply. The cutting tool is moved so that the cutting tool or its cutting edge 153 in a direction perpendicular to the axis 118 lying plane along a predefined, closed trajectory (cutting path) moves. The 2 and 3 show by way of example with dotted lines some possible trajectories BK1, BK3, which will be explained later in detail.

As a counter element for the cutting tool is a mandrel 155 (Cutting pin), which is located inside the developing spring and an oblique cutting edge 156 which, when disconnected with the cutting tool 152 interacts.

The cutting tool 152 is also referred to below as a cutting blade or cutting knife 152 designated. The trajectory of the cutting tool, which is also referred to as the cutting curve, is defined here as the trajectory of the cutting edge 153 of the cutting tool in the direction perpendicular to the central axis 118 lying working plane of the cutting tool is covered.

The spring winding machine or the cutting device is designed so that the cutting path, that is, the trajectory of the cutting tool in the cutting movement, can be set and changed to almost any course within a design-related work area AB. This adjustment requires no operator intervention in the mechanical components. Rather, the setting is via the operating unit 104 the spring coiling machine by means of the control unit 102 to program. The course of the trajectory can be optimally adapted to different conditions in the spring production.

By means of a freely programmable trajectory adjustment system, it is possible to control the shape and / or the position of the trajectory to be traversed by the cutting tool by programming the control unit 102 pretend. It is possible, in addition to the even in conventional spring winding machines occasionally adjustable cutting process of the straight section (cutting tool is reciprocated along a rectilinear trajectory) and the so-called rotary cut, in which the cutting tool for separating the wire to a symmetry plane mirror-symmetrical elliptical or egg-shaped Trajectory traverses to set also unbalanced courses of the trajectory, which have a deviating from an ellipse shape or egg shape, non-mirror-symmetric course.

In the embodiment, a cutting tool drive system is provided for this purpose, the two via the control unit 102 independently controllable electric drives 165 . 175 includes (cf. 6 ), which transmits tool movements with the cutting tool 152 are coupled. Both drives are electric servo drives. A first drive serves to generate a linear reciprocating first movement of the cutting tool along a first direction 154 in the longitudinal direction of the cutting tool 152 runs. The second drive generates a second movement of the cutting tool superimposed on this first movement and, in the example, acts as an actuator which during the linear reciprocating movement of the cutting tool in the first direction additionally rotates the reciprocating cutting tool about an axis perpendicular to the working plane generated. By superposition of the pivoting movement with the linear reciprocating, substantially vertically extending movement variable trajectories can be realized for the cutting tool.

By the size or amplitude of the pivoting movement, for example, the width of an elliptical trajectory (measured perpendicular to the first direction 154 ). If no pivoting movement is carried out, so that solely the linear movement remains, a straight cut is feasible. Due to the size or amplitude of the linear movement, the height of the elliptical trajectory (measured parallel to the first direction) can be adjusted in a rotational section within the design limits, the straight line in the first direction in the stroke 154 equivalent. By specifying corresponding starting points of the drives, the position of the trajectory, for example the position of an elliptical trajectory, can additionally be changed in order to be able to optimally position the latter to the cutting mandrel and to the wire.

The first drive with its associated components should provide some flywheel mass to provide enough kinetic energy to cut. The second drive should have high dynamics to allow rapid movement changes when needed.

For further explanation see 2 the rest position of the cutting tool 152 shown. 3 shows a situation where the cutting edge 153 of the cutting tool when moving in the direction of the wire just at the point of impact 117 located on the wire. The dot-dash lines represent some possible paths of the cutting edge of the cutting tool, so the trajectories, dar. The cutting edge can theoretically due to the mechanical conditions of the embodiment, an approximately trapezoidal work area AB shut down when the first drive and the second drive each perform their maximum strokes. Within this workspace almost arbitrarily shaped and placed trajectories can be displayed, of course, the required dynamics in the implementation of the cutting movements certain trajectory, such as those with corners or sharp curves, usually not practical. Within the working area, however, narrow or wide ellipses, straight paths, oblique paths, shape curves, laterally offset ellipses or other trajectories may be generated. Thus, the course of the cutting path control technology can be optimally adapted to the circumstances.

Some examples of particularly advantageous trajectories under different production conditions are explained in more detail below, for example in connection with 8th ,

The 4 to 6 show schematically different views of components of the cutting device 150 out 1 , which allow the flexible setting of different trajectories. At the vertical front wall 106 the spring coiling machine 100 is a substantially rectangular pivot plate 160 rotatable on a horizontal pivot axis 161 stored. The reciprocating pivotal movement is via a horizontally oriented pivot shaft 162 realized that via a second drive 165 is driven, which serves as a pivot drive. The pivot shaft 162 has at its front end an eccentric pin 163 on, a backdrop 164 carries, which in a rectangular recess of the pivot plate 160 is movably guided in the longitudinal direction of the pivot plate.

On the pivot axis 161 facing away from the front of the pivot plate 160 is a linear guide 170 attached, which is aligned in the longitudinal direction of the pivot plate and a carriage 171 carries on which a tool holder 155 for the cutting tool 152 is attached. The cutting tool protrudes from the tool holder at the lower end. At the upper end is by means of a retaining pin a connecting rod 172 pivotally mounted, which is infinitely adjustable in its length and at its other end with an eccentric pin 173 connected to the front of a cutting shaft 174 located. This is about the first drive 175 driven.

The first and the second drive, which are each formed by electric servo drives, via the control device 102 principle, independently, but in a coordinated manner, driven. The "coupling" of the drives does not take place mechanically, but only via software, ie via the control program. This results in a high degree of flexibility in the generation of working movements of the cutting tool.

The first drive 175 drives over the cutting shaft 174 the substantially vertical linear cutting movement of the carriage 171 on, the cutting tool 152 wearing. The over the second drive 165 driven pivot shaft 162 on the other hand acts only as an actuator and is operated intermittently, so usually does not perform 360 ° rotation. The cutting shaft 174 however, is operated continuously in the same direction of rotation and varying rotational speed to provide the necessary energy and speed for the separation process. However, it would also be possible to intermittently operate the cutting drive (first drive). This can be useful, for example, if the height of the trajectory up to the maximum achievable height to be reduced.

The first drive 175 (Cutting drive) and the second drive 165 (Rotary actuator) are independently controllable, so that theoretically any superimpositions of the linear movement along the first direction 154 and this in the transverse direction superimposed pivoting movement are possible.

The pivoting element 160 can be fixed in the vertical position by a locking device, which can be moved via machine commands in engagement or out of engagement with the pivot arm, so that the carriage 171 moved only in the vertical direction. The locking device may comprise, for example, an electrically or pneumatically operable bolt, which can be retracted from behind (from the machine side) into a bore on the rear side of the pivot plate. By locking the arrangement with respect to the pivoting movement is free of play and there is a stiffening of the construction for the vertical section, so that large cutting forces can be transmitted without undue stress on the components of the cutting device.

The trajectory adjustment system of the embodiment is designed to be very user friendly, so that the complex settings for the correct trajectory can be made intuitively by less experienced operators. 7 shows an example of a view of the control unit with a graphical user interface that supports the user in the adjustment. In the rectangular graphic representation shown on the left, a symbol is at the bottom of the picture 155 ' for the currently used cropper, a symbol 130 ' for the holder of the currently used incline tool and a symbol 115 ' shown for the wire. The tools 155 and 130 form in the example the relevant interference contours that must be taken into account when designing the trajectory of the cutting blade. You are in through the control unit 102 generated graphic in the correct position and displayed in the correct size ratio. The oblique, dashed line in extension of the oblique cutting edge (chamfer on the cutting mandrel) helps in the correct adjustment of the cutting gap. The cutting gap is defined here as the vertical distance between the cutting edge or the dashed line and a parallel tangent to the trajectory BK1 or BK4 at the point of impact 117 on the wire. For optimum cutting results, this kerf should generally be in the range between 30 and 70 ° of the wire diameter.

At the user interface, buttons for setting trajectory parameters are provided to the operator to the right of the graphical representation. With the upper button ELB the ellipse width between a minimum value (0) and a maximum value (90) can be adjusted by pressing the arrow keys. These values each refer to a constant height of the ellipse. When setting the lower limit value ELB = 0, a straight cut (linear reciprocation of the cutting tool) is thus executed.

The underlying VH button actuates the arrow keys, a horizontal displacement of the entire closed trajectory between a minimum value VH = 0 and a maximum value. This horizontal displacement of the trajectory allows u.a. the use of identical tools (mandrel, cutting knife) at different trajectories. If only the width of the ellipse could be adjusted, the center of the trajectory would remain unchanged and the point of impact of the cutting tool on the wire would move away from the mandrel or in the direction of the mandrel. The cutting conditions would usually worsen as a result. Without lateral adjustability, theoretically, the cutting blade would have to have a slightly different cutting geometry for each trajectory.

It can be provided that the adjustment of the ellipse width and the adjustment of the horizontal position of the trajectory are linked in such a way via software that only parameter combinations are adjustable, which do not or only slightly shift the position of the impact point, that an optimal cut is possible , If necessary, a warning signal can be generated if parameters do not match each other sufficiently well.

The underlying N button adjusts the slope of the trajectory. A value N = 0 corresponds to a vertically oriented trajectory (long semiaxis vertical), with negative values the trajectory is tilted to the left, that is to say in the direction of retraction, and in the case of positive values to the right in the direction of the wind pins. The underlying button VV causes a shift of the trajectory as a whole in the vertical direction. The lower button D is used to enter the value for the current wire diameter. Other configurations which in effect provide the same, equivalent or similar adjustment possibilities are possible.

The setting options are given by way of example only. Individual settings can be completely eliminated in variants. Setting options can be practically implemented in different ways. Some or all parameters may e.g. be entered directly into the control software, so that a user interface with sliders or the like is not necessary. The vertical adjustment of the trajectory is usually not programmed, but can be realized by manual adjustment of the length of the connecting rod. It is also possible to deposit in a memory of the controller a number of predefined orbital base types, e.g. are optimized in terms of production speed or other parameters. These can then be called up by the operator and, if necessary, fine-tuned by changing individual parameters and adapted to the conditions of the spring coil process currently being set up.

The following are some selected types of cuts with their specific applications and properties based on 8th explained. If necessary, a part of the cutting tool SW, a part of the cutting mandrel DO, the tail of the remaining wire DR with chisel SG and the trajectory BK of the cutting edge of the cutting tool are shown schematically. The various elements are shown exploded in the vertical direction for purposes of illustration.

The system can be set for a straight cut ( 8A ), in which the cutting tool only moves vertically and a cutting tool and a cutting pin are each selected with a vertical cutting edge. The ellipse width and the inclination are each set to zero for this purpose. The wire feed is stopped for the cut. On the wire, this type of cut typically produces a cutting burr SG, which is directed inward in the direction of the center axis of the spring.

The system can also be set to a rotary cut or a rotating elliptical cut ( 8B ). In this case, the cutting tool moves on an elliptical trajectory with horizontal and vertical component of motion, with a fixed height-width ratio is set. The cutting tool used and the cutting edge used in this case should have an inclined cutting edge or chamfer. In this type of cutting, the cutting burr is generally directed in the direction of the wire's winder, so that the spring's inside diameter is not or hardly limited. For this purpose, only the ellipse width ELB is set to the desired value.

The embodiment makes this also available in conventional spring coiling machines frequently available cut types with an enlarged compared to the prior art spectrum with simplified adjustment. The above-described straight cut (vertical tool movement in conjunction with knife and cutting cutter with vertical cut edge) can be modified to a modified straight cut ( 8C ). A cutting tool and a cutting edge with a vertical cutting edge are also used. However, the cutting tool does not move only vertically, but also has a slight horizontal component of motion, resulting in a narrow elliptical shape (with adjustable height-to-width ratio). Again, there is a cutting ridge, which is directed primarily inward towards the spring center axis. However, since due to the slight elliptical shape, the upward movement of the cutting tool after the vertical cutting movement takes place at a small distance to the cutting edge and the cut surface on the wire, the cutting tool is no longer in contact with the cut wire on the return path. This can significantly reduce tool wear. Typical ratios between height and width of the substantially elliptical trajectory may, for example, be in the range between 5: 1 and 30: 1, in particular in the range between 12: 1 and 25: 1.

Furthermore, many other variants of the rotary cut are available. For the cutting method "variable rotating cut" ( 8B ), the wire catch for the cutting operation is stopped. A knife (cutting tool) and a cutting punch with slanted cut edges are used. The cutting edge of the tool moves along an ellipse with variably adjustable height-to-width ratio, typically at relatively narrow to mid-latitude ellipses. Here you can work with "vertical slope" or "slope parallel". The result is a cutting burr, which is arranged substantially in the direction of the wire's wire. The cutting ridge is thus within the inner and outer envelope of the spring, so does not project inwardly or outwardly beyond the spring.

For the cutting type "flying rotating cut" ( 8D ), the spring coiling machine operates with a continuous wire feed or wire feed in conjunction with a flying rotating cut. In this case, the cutting tool moves with a horizontal and vertical component of motion on an elliptical trajectory with a relatively wide ellipse, ie smaller height-to-width ratio. As a result, relatively high horizontal components of the movement are achieved during the cut. The cutting tool and cutting mandrel each have corresponding slanted cut edges. Here in the example case of vertical slope (lower pitch tool) worked. The circulation may be elliptical or circular, depending on the construction. The rotational speed is usually non-uniform.

In this continuous flywheel continuous wire feed mode, the wire is continuously advanced or retracted at a constant or varying finite feed rate. So there is no stoppage of wire feed over the production of many consecutive coil springs. This increases the piece performance. If the wire feed is running constantly, the wire supply, which is held for example on a reel, not constantly accelerated and decelerated. This also applies to the drives of the feeder and the tools. As a result, the energy requirement per spring is reduced in comparison with methods with a standing cut, in which the wire feed for the cutting process must be stopped. In addition, there is no jerky pull on the wire and no stick-slip effect, whereby the quality of the springs produced can be significantly increased compared to methods with a standing cut.

In the "flying cut" mode, the moving speed of the cutting tool along the trajectory is automatically coordinated with the drawing speed of the wire in such a manner that the shape of the trajectory is adapted to the rotational speed of the cutting tool such that the moving speed of the cutting edge in the horizontal direction (FIG. substantially parallel to the wire feed direction) in a time interval beginning before the penetration of the cutting edge into the wire until the cut contact between the cutting tool and the wire is greater than the wire feed speed. Calling the time interval in which the cutting tool is in engagement with the wire as "wire collision area", the cutting tool should be accelerated so that its horizontal component (parallel to the wire feed speed) is greater than that of the wire before the beginning of the cut and only after leaving the wire, the wire speed falls below again. Therefore, in this mode usually flat elliptical trajectories are to be set with a relatively large width and correspondingly large horizontal component of the movement speed.

The elliptical paths of the cutting tool described here by way of example represent only a few special forms of the theoretically possible trajectories. An example of an asymmetrical optimized trajectory with finite height-width ratio is the curve BK3 in FIG 2 This results in the same advantages during the cut as in an elliptical curved path BK1, but is on the side of the pitch tool 130 requires less space, so that such trajectory forms can be useful especially in cramped conditions in the field of forming tools. There are many other web shapes conceivable, for example, a flattened ellipse in the area of the chamfer on Abschneidorn ( 8E ). Here, the cutting path can for example be placed so that the flattened part runs with a largely straight course parallel to the chamfer on the cutting edge. From the basic shape of the ellipse or the egg shape, many useful unsymmetrical trajectory shapes can be adjusted via suitable deformations.

Limitations of the theoretically possible trajectories are on the one hand by interference edges or collision points with other tools, such as Windefinger or pitch tools, given and conditional on the other by the limits of the dynamics and performance of the drive motors. These boundary conditions can be taken into account, inter alia, in a method variant in which a teach-in programming takes place. In this variant of the method, the potential collision points in the area of the forming tools are manually approached by the operator with the cutting tool. If the cutting tool is positioned at a collision point, this position is taken over by an input of the operator in the control, that is, the controller announced. Using these positions, the trajectory is then automatically calculated so that these collision areas are excluded from the curved path selected by the operator or not approached, but are bypassed.

By the claimed invention different technical tasks can be solved alternatively or cumulatively. On the one hand, there is an expansion of the range of applications compared to conventional systems with straight cut and rotating cut. If possible, an optimization of the unit performance and the machine output can be achieved. In many cases, an optimization of the sectional image results in the severed wire. Furthermore, an optimization of the position of the remaining burrs on the wire with respect to the intended use or further processing of the springs may result. Not least, suitable settings can lead to an increase in the service life of the cutting tools, in particular when cutting straight.

By adjusting the position and inclination of the trajectory or curved path in the cutting process, that is, while the cutting tool is in contact with the wire, the inclination of the cutting edge on the wire can be determined. Furthermore, the inclination or position of the remaining chisel can be determined via these settings. In the modified straight cut (narrow ellipse), the cut edge is spared or prevented outbreaks, since the cutting tool is relieved by the lateral moving away from the wire edge after completion of the cut of lateral lateral forces caused by the wire.

These advantages can be set much more easily thanks to the programmability of the various trajectories without mechanical intervention on the spring coiling machine than in conventional spring coiling machines, which had a possibility for setting different trajectories.

In 9 another constructive variant for components of the cutting device is shown, which also provides all the settings described above. Again, this is held by a tool holder cutting tool 952 on a sledge 971 mounted by a linear guide 970 is guided linearly movable. The linear guide is on a plate-shaped pivoting element or a pivot plate 960 mounted, which is rotatably mounted on a horizontal pivot axis which is fixed to the vertical front wall of the spring coiling machine. There are two separate, through the control device 902 provided independently controllable drives for the linear movement and the pivoting movement. A first drive 975 drives the horizontal cutting shaft 974 on, which has an eccentric pin on its front side, which is rotatably mounted in a backdrop. The gate is displaceable perpendicular to the longitudinal direction of the carriage in a recess of the carriage 971 guided. A rotation of the cutting shaft causes in this way an up and down movement of the carriage 971 along the first direction 954 , ie in the longitudinal direction of the pivoting element 960 , The reciprocating pivotal movement of the pivoting element is by the second drive 965 causes the pivot shaft 962 intermittently or reciprocally driving. This has on its front side an eccentric pin which is rotatably mounted in a gate, which in a recess of the pivoting element 960 is guided in the longitudinal direction movable.

In this embodiment, therefore, the pivot shaft 962 above the cutting shaft 974 arranged. In contrast, the arrangement in the embodiment of the 4 to 6 conversely, there is the cutting shaft above the pivot shaft. These mechanical components of the cutting tool drive system can thus be designed and arranged in different ways depending on the available space and other requirements.

Claims (8)

Spring winding machine ( 100 ) for the production of coil springs ( 200 ) by spring winds comprising: a feeder ( 110 ) for feeding wire ( 115 ) to a forming device ( 120 ), wherein the forming device at least one Windewerkzeug ( 122 . 124 ) and at least one pitch tool ( 130 ), a cutting device ( 150 ) for severing a completed helical spring from the supplied wire after completion of a forming operation, the cutting means comprising a cutting tool which is movable along a predetermined closed trajectory by means of a cutting tool drive system; a control device ( 180 ) for controlling the feeder, the forming device and the cutting device based on an NC control program, characterized by, a programmable trajectory adjustment system for adjusting the shape and / or position of the trajectory to be traversed by the cutting tool, wherein optionally a rectilinear trajectory, one a symmetry plane mirror-symmetrical elliptical or egg-shaped trajectory with a predetermined ratio of height to width or an asymmetrical trajectory with a deviating from an ellipse shape or egg shape non-mirror-symmetric course is adjustable. Spring coiling machine according to claim 1, characterized in that the cutting tool drive system by the control device ( 102 . 902 ) controllable first drive ( 175 . 975 ) for generating a first movement of the cutting tool ( 152 . 952 ) and a independently controllable by the first drive by the control device second drive ( 165 . 965 ) for generating a second movement of the cutting tool superimposed on the first movement. Spring coiling machine according to claim 2, characterized in that the first drive ( 175 . 975 ) for generating a linear reciprocating first movement of the cutting tool along a first direction ( 154 . 954 ), which in the longitudinal direction of the cutting tool ( 152 . 952 ), and that the second drive ( 165 . 965 ) is designed as an actuator which additionally generates during the linear reciprocation of the cutting tool in the first direction, a pivoting movement of the reciprocating cutting tool about an axis perpendicular to a working plane axis. Spring coiling machine according to claim 2 or 3, characterized in that the cutting tool ( 152 . 952 ) on a carriage ( 171 . 971 ) mounted along a linear guide ( 170 . 970 ) in a first direction ( 154 . 954 ) is linearly movable back and forth, and that the linear guide on a pivoting element ( 160 . 960 ), which is pivotable about a pivot axis extending perpendicular to the first direction, wherein the first drive ( 175 . 975 ) with the carriage and the second drive ( 165 . 965 ) is coupled to the pivoting element. Spring coiling machine according to one of the preceding claims, characterized in that the control device ( 102 . 902 ) is configured for teach-in programming. Spring coiling machine according to claim 5, characterized in that the control device is configured such that in a programming configuration, the cutting tool ( 152 . 952 ) is positionable manually at one or more positions in the region of a desired trajectory, the coordinates of the positions in a memory of the controller can be stored, using the coordinates a trajectory is calculated and the cutting tool in an operating configuration under the control of the controller along the trajectory is movable. A spring coiling machine according to any one of the preceding claims, characterized in that the trajectory adjustment system is configured to independently allow at least three of the following settings: (i) an ellipse width of the trajectory between a minimum value 0 for a straight cut and a maximum value related to a maximum Height of the ellipse; (ii) a horizontal displacement of the entire trajectory between a minimum value and a maximum value; (iii) an inclination of the trajectory between a value 0 for a vertically oriented trajectory, an inclination of the trajectory towards the feeder and an inclination of the trajectory in the opposite direction; (iv) a displacement of the trajectory as a whole in the vertical direction. Spring coiling machine according to one of the preceding claims, characterized in that the feed device is configured for a continuous supply of the wire and the cutting device ( 150 ) a rotating drivable cutting tool ( 152 ), wherein the spring winding machine is configured such that the finished coil spring is separated by a rotating flying cut from the supplied wire.

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