U.S. patent application number 14/251898 was filed with the patent office on 2014-10-23 for spring winding machine with an adjustable cutting device.
This patent application is currently assigned to WAFIOS AG. The applicant listed for this patent is WAFIOS AG. Invention is credited to Andreas Sigg.
Application Number | 20140311204 14/251898 |
Document ID | / |
Family ID | 50473108 |
Filed Date | 2014-10-23 |
United States Patent
Application |
20140311204 |
Kind Code |
A1 |
Sigg; Andreas |
October 23, 2014 |
SPRING WINDING MACHINE WITH AN ADJUSTABLE CUTTING DEVICE
Abstract
A spring winding machine that manufactures helical springs by
spring winding includes a feed device that feeds wire to a shaping
device, wherein the shaping device has a winding tool and a pitch
die; a cutting device that separates a finished helical spring from
the wire after termination of shaping, wherein the cutting device
has a cutting tool which, by a drive system, can be moved along a
predefinable closed trajectory; a control device that controls the
feed device, the shaping device and the cutting device on the basis
of an NC control program; and a programmable trajectory-setting
system that sets the shape and/or position of the trajectory to be
passed through by the cutting tool, wherein a trajectory which is
mirror-symmetrical with respect to a plane of symmetry and has a
predefinable ratio of height to width.
Inventors: |
Sigg; Andreas; (Engstingen,
DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
WAFIOS AG |
Reutlingen |
|
DE |
|
|
Assignee: |
WAFIOS AG
Reutlingen
DE
|
Family ID: |
50473108 |
Appl. No.: |
14/251898 |
Filed: |
April 14, 2014 |
Current U.S.
Class: |
72/139 |
Current CPC
Class: |
B21F 3/06 20130101; B21F
3/02 20130101; B21F 35/00 20130101; B21F 11/005 20130101 |
Class at
Publication: |
72/139 |
International
Class: |
B21F 3/06 20060101
B21F003/06; B21F 11/00 20060101 B21F011/00 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 18, 2013 |
DE |
102013207028.4 |
Claims
1. A spring winding machine that manufactures helical springs by
spring winding comprising: a feed device that feeds wire to a
shaping device, wherein the shaping device has at least one winding
tool and at least one pitch die; a cutting device that separates a
finished helical spring from the fed wire after termination of a
shaping operation, wherein the cutting device has a cutting tool
which, by a cutting tool drive system, can be moved along a
predefinable closed trajectory; a control device that controls the
feed device, the shaping device and the cutting device on the basis
of an NC control program; and a programmable trajectory-setting
system that sets the shape and/or position of the trajectory to be
passed through by the cutting tool, wherein a linear trajectory, an
elliptical or egg-shaped trajectory, which is mirror-symmetrical
with respect to a plane of symmetry and has a predefinable ratio of
height to width, or an asymmetrical trajectory with a
non-mirror-symmetrical profile which deviates from an elliptical
shape or egg shape can optionally be set.
2. The spring winding machine according to claim 1, wherein the
cutting tool drive system has a first drive which can be actuated
by the control device and generates a first movement of the cutting
tool, and a second drive which can be activated by the control
device independently of the first drive and generates a second
movement of the cutting tool which is superimposed on the first
movement.
3. The spring winding machine according to claim 2, wherein the
first drive generates a linear to-and-fro first movement of the
cutting tool in a first direction running in the longitudinal
direction of the cutting tool, and the second drive is an actuating
drive which, during the linear to-and-fro movement of the cutting
tool in the first direction, additionally generates a pivoting
movement of the cutting tool, moved to and fro, about an axis
running perpendicular to a working plane.
4. The spring winding machine according to claim 2, wherein the
cutting tool is attached to a carriage which can be moved linearly
to and fro along a linear guide in a first direction, and the
linear guide is attached to a pivoting element which can pivot
about a pivoting axle running perpendicularly to the first
direction, and the first drive is coupled to the carriage and the
second drive is coupled to the pivoting element.
5. The spring winding machine according to claim 1, wherein the
control device is configured for teach-in programming.
6. The spring winding machine according to claim 5, wherein the
control device is configured such that in a programming
configuration, the cutting tool can be positioned manually at one
or more positions in the region of a desired trajectory,
coordinates of the positions can be stored in a memory of the
control device, a trajectory can be calculated using the
coordinates, and the cutting tool can be moved along the trajectory
in an operating configuration under control of the control
device.
7. The spring winding machine according to claim 1, wherein the
trajectory-setting system is configured to permit at least three of
the following settings independently of one another: (i) an ellipse
width of the trajectory between a minimum value 0 for a straight
cut and a maximum value relating to a maximum height of the
ellipse; (ii) horizontal shifting of the entire trajectory between
a minimum value and a maximum value; (iii) inclination of the
trajectory between a value 0 for a vertically orientated
trajectory, an inclination of the trajectory in the direction of
the feed device and an inclination of the trajectory in the
opposite direction; (iv) shifting of the trajectory in its entirety
in the vertical direction.
8. The spring winding machine according to claim 1, wherein the
feed device is configured to continuously feed the wire, and the
cutting device has a cutting tool which can be driven in rotation,
and the spring winding machine is configured such that the finished
helical spring is separated from the feed wire by a rotating flying
cut.
9. The spring winding machine according to claim 3, wherein the
cutting tool is attached to a carriage which can be moved linearly
to and fro along a linear guide in a first direction, and the
linear guide is attached to a pivoting element which can pivot
about a pivoting axle running perpendicularly to the first
direction, and the first drive is coupled to the carriage and the
second drive is coupled to the pivoting element.
10. The spring winding machine according to claim 2, wherein the
control device is configured for teach-in programming.
11. The spring winding machine according to claim 3, wherein the
control device is configured for teach-in programming.
12. The spring winding machine according to claim 4, wherein the
control device is configured for teach-in programming.
13. The spring winding machine according to claim 2, wherein the
trajectory-setting system is configured to permit at least three of
the following settings independently of one another: (i) an ellipse
width of the trajectory between a minimum value 0 for a straight
cut and a maximum value relating to a maximum height of the
ellipse; (ii) horizontal shifting of the entire trajectory between
a minimum value and a maximum value; (iii) inclination of the
trajectory between a value 0 for a vertically orientated
trajectory, an inclination of the trajectory in the direction of
the feed device and an inclination of the trajectory in the
opposite direction; (iv) shifting of the trajectory in its entirety
in the vertical direction.
14. The spring winding machine according to claim 3, wherein the
trajectory-setting system is configured to permit at least three of
the following settings independently of one another: (i) an ellipse
width of the trajectory between a minimum value 0 for a straight
cut and a maximum value relating to a maximum height of the
ellipse; (ii) horizontal shifting of the entire trajectory between
a minimum value and a maximum value; (iii) inclination of the
trajectory between a value 0 for a vertically orientated
trajectory, an inclination of the trajectory in the direction of
the feed device and an inclination of the trajectory in the
opposite direction; (iv) shifting of the trajectory in its entirety
in the vertical direction.
15. The spring winding machine according to claim 4, wherein the
trajectory-setting system is configured to permit at least three of
the following settings independently of one another: (i) an ellipse
width of the trajectory between a minimum value 0 for a straight
cut and a maximum value relating to a maximum height of the
ellipse; (ii) horizontal shifting of the entire trajectory between
a minimum value and a maximum value; (iii) inclination of the
trajectory between a value 0 for a vertically orientated
trajectory, an inclination of the trajectory in the direction of
the feed device and an inclination of the trajectory in the
opposite direction; (iv) shifting of the trajectory in its entirety
in the vertical direction.
16. The spring winding machine according to claim 5, wherein the
trajectory-setting system is configured to permit at least three of
the following settings independently of one another: (i) an ellipse
width of the trajectory between a minimum value 0 for a straight
cut and a maximum value relating to a maximum height of the
ellipse; (ii) horizontal shifting of the entire trajectory between
a minimum value and a maximum value; (iii) inclination of the
trajectory between a value 0 for a vertically orientated
trajectory, an inclination of the trajectory in the direction of
the feed device and an inclination of the trajectory in the
opposite direction; (iv) shifting of the trajectory in its entirety
in the vertical direction.
17. The spring winding machine according to claim 6, wherein the
trajectory-setting system is configured to permit at least three of
the following settings independently of one another: (i) an ellipse
width of the trajectory between a minimum value 0 for a straight
cut and a maximum value relating to a maximum height of the
ellipse; (ii) horizontal shifting of the entire trajectory between
a minimum value and a maximum value; (iii) inclination of the
trajectory between a value 0 for a vertically orientated
trajectory, an inclination of the trajectory in the direction of
the feed device and an inclination of the trajectory in the
opposite direction; (iv) shifting of the trajectory in its entirety
in the vertical direction.
Description
TECHNICAL FIELD
[0001] This disclosure relates to spring winding machines that
manufacture helical springs by spring winding.
BACKGROUND
[0002] Helical springs are machine elements required in numerous
application areas in large numbers and different configurations.
Helical springs, which are also referred to as wound torsion
springs, are usually manufactured from spring wire and, depending
on the load present during use, are configured as tension springs
or compression springs. Compression springs, in particular bearing
springs, are required, for example, in large quantities for
automobile production.
[0003] Helical springs are usually manufactured nowadays by spring
winding using numerically controlled spring winding machines. Thus,
a wire (spring wire) is fed to a shaping device of the spring
winding machine by a feed device under the control of an NC control
program, and is shaped using tools of the shaping device to form a
helical spring. The tools generally include one or more
positionally adjustable winding pins to secure and, if appropriate,
change the diameter of spring windings and one or more pitch dies
by which the local pitch of the spring windings is determined in
each phase of the fabrication process. After the termination of a
shaping operation, a finished helical spring is separated from the
fed wire by a cutting device under the control of the NC control
program.
[0004] During the manufacture of springs, the type of cut is
frequently of great significance since it also determines certain
properties of the finished helical spring. Generally, three types
of cutting methods are differentiated, specifically what is
referred to as a "straight cut," "rotational cut" and "torsional
cut." In the case of the straight cut, a cutting tool carries out a
straight linear cutting movement during cutting of the wire. In the
case of the rotational cut, the cutting edge of the cutting tool is
guided along an essentially elliptical trajectory to cut the wire.
In the case of the torsional cut, the wire is loaded mechanically
such that it can be separated by torsional loading. A torsional cut
can provide a burr-free cut. In the case of the other two types of
cut, cutting burrs are generally produced at the cutting surface,
and in some cases they have to be removed by brushing, blasting or
grinding before further use of the helical springs.
[0005] EP 0 804 979 A1 describes components of a cutting device for
a spring winding machine which permit the cutting device to be
reset to optionally carry out a straight cut or a rotational cut,
in which the cutting tool is guided along a droplet-shaped
trajectory. The cutting tool is held in a carriage guided in a
linearly movable fashion in a linear guide. The linear guide is
mounted pivotably. A drive motor is coupled to the carriage via a
drive shaft, an eccentric and a connecting rod and can as a result
bring about the linear to-and-fro movement of the cutting tool. The
pivoting movement of the linear guide can be brought about by a
second drive shaft acting on the linear guide via an eccentric. The
drive motor can optionally be disengaged from the second drive
shaft or be engaged with the second drive shaft. If a drive
connection is not set, the cutting device carries out a straight
cut. During coupling of the second drive shaft to the drive motor,
the linear guide carries out an oscillating pivoting movement, with
the result that a droplet-shaped trajectory of the cutting tool is
produced as a result of the superimposition of the straight linear
movement and the pivoting movement.
[0006] U.S. Pat. No. 7,055,356 B2 describes components of a cutting
device for a spring manufacturing machine which are constructed
such that the cutting tool can be moved along an essentially
elliptical trajectory. The shape of the trajectory can be changed
by manually shifting the position of a sliding element along a
linear guide.
[0007] JP 2001-293533 A shows components of a cutting device of a
spring manufacturing machine. A carriage which is linearly movable
in the vertical direction is provided to the front wall of the
machine, it being possible to move the carriage up and down using a
drive motor via a drive shaft, an eccentric and a connecting rod.
The carriage supports on its front side a pivotable element which
supports the cutting tool. A further drive motor generates a
pivoting movement of this pivoting element via a drive shaft and a
Cardan joint with axial length compensation about a pivoting axle
mounted in the sliding element in the carriage. The position of the
pivoting element on the carriage can be changed by a further shaft
with a Cardan joint to change the position of the cutting tool in
the spring axial direction.
[0008] It could therefore be helpful to provide a user-friendly
spring winding machine which can be used in a flexible way and
which can manufacture with a high level of productivity helical
springs in terms of their cross section, position of the cutting
burr and other spring parameters in accordance with their
specification.
SUMMARY
[0009] I provide a spring winding machine that manufactures helical
springs by spring winding including a feed device that feeds wire
to a shaping device, wherein the shaping device has at least one
winding tool and at least one pitch die; a cutting device that
separates a finished helical spring from the fed wire after
termination of a shaping operation, wherein the cutting device has
a cutting tool which, by a cutting tool drive system, can be moved
along a predefinable closed trajectory; a control device that
controls the feed device, the shaping device and the cutting device
on the basis of an NC control program; and a programmable
trajectory-setting system that sets the shape and/or position of
the trajectory to be passed through by the cutting tool, wherein a
linear trajectory, an elliptical or egg-shaped trajectory, which is
mirror-symmetrical with respect to a plane of symmetry and has a
predefinable ratio of height to width, or an asymmetrical
trajectory with a non-mirror-symmetrical profile which deviates
from an elliptical shape or egg shape can optionally be set.
[0010] I also provide the spring winding machine wherein the
cutting tool drive system has a first drive which can be actuated
by the control device and generates a first movement of the cutting
tool, and a second drive which can be activated by the control
device independently of the first drive and generates a second
movement of the cutting tool which is superimposed on the first
movement.
[0011] I further provide a spring winding machine wherein the
cutting tool drive system has a first drive which can be actuated
by the control device and generates a first movement of the cutting
tool, and a second drive which can be activated by the control
device independently of the first drive and generates a second
movement of the cutting tool which is superimposed on the first
movement and wherein the first drive generates a linear to-and-fro
first movement of the cutting tool in a first direction running in
the longitudinal direction of the cutting tool, and the second
drive is an actuating drive which, during the linear to-and-fro
movement of the cutting took in the first direction, additionally
generates a pivoting movement of the cutting tool, moved to and
fro, about an axis running perpendicular to a working plane.
[0012] I further still provide a spring winding machine wherein the
cutting tool drive system has a first drive which can be actuated
by the control device and generates a first movement of the cutting
tool, and a second drive which can be activated by the control
device independently of the first drive and generates a second
movement of the cutting tool which is superimposed on the first
movement and wherein the cutting tool is attached to a carriage
which can be moved linearly to and fro along a linear guide in a
first direction, and the linear guide is attached to a pivoting
element which can pivot about a pivoting axle running
perpendicularly to the first direction, and the first drive is
coupled to the carriage and the second drive is coupled to the
pivoting element.
[0013] I further yet provide a spring winding machine that
manufactures helical springs by spring winding including a feed
device that feeds wire to a shaping device, wherein the shaping
device has at least one winding tool and at least one pitch die; a
cutting device that separates a finished helical spring from the
fed wire after termination of a shaping operation, wherein the
cutting device has a cutting tool which, by a cutting tool drive
system, can be moved along a predefinable closed trajectory; a
control device that controls the feed device, the shaping device
and the cutting device on the basis of an NC control program; and a
programmable trajectory-setting system that sets the shape and/or
position of the trajectory to be passed through by the cutting
tool, wherein a linear trajectory, an elliptical or egg-shaped
trajectory, which is mirror-symmetrical with respect to a plane of
symmetry and has a predefinable ratio of height to width, or an
asymmetrical trajectory with a non-mirror-symmetrical profile which
deviates from an elliptical shape or egg shape can optionally be
set and wherein the control device is configured for teach-in
programming.
[0014] I also further provide a spring winding machine that
manufactures helical springs by spring winding including a feed
device that feeds wire to a shaping device, wherein the shaping
device has at least one winding tool and at least one pitch die; a
cutting device that separates a finished helical spring from the
fed wire after termination of a shaping operation, wherein the
cutting device has a cutting tool which, by a cutting tool drive
system, can be moved along a predefinable closed trajectory; a
control device that controls the feed device, the shaping device
and the cutting device on the basis of an NC control program; and a
programmable trajectory-setting system that sets the shape and/or
position of the trajectory to be passed through by the cutting
tool, wherein a linear trajectory, an elliptical or egg-shaped
trajectory, which is mirror-symmetrical with respect to a plane of
symmetry and has a predefinable ratio of height to width, or an
asymmetrical trajectory with a non-mirror-symmetrical profile which
deviates from an elliptical shape or egg shape can optionally be
set and wherein the control device is configured for teach-in
programming and wherein the control device is configured such that
in a programming configuration the cutting tool can be positioned
manually at one or more positions in the region of a desired
trajectory, coordinates of the positions can be stored in a memory
of the control device, a trajectory can be calculated using the
coordinates, and the cutting tool can be moved along the trajectory
in an operating configuration under control of the control
device.
[0015] I still further provide a spring winding machine that
manufactures helical springs by spring winding including a feed
device that feeds wire to a shaping device, wherein the shaping
device has at least one winding tool and at least one pitch die; a
cutting device that separates a finished helical spring from the
fed wire after termination of a shaping operation, wherein the
cutting device has a cutting tool which, by a cutting tool drive
system, can be moved along a predefinable closed trajectory; a
control device that controls the feed device, the shaping device
and the cutting device on the basis of an NC control program; and a
programmable trajectory-setting system that sets the shape and/or
position of the trajectory to be passed through by the cutting
tool, wherein a linear trajectory, an elliptical or egg-shaped
trajectory, which is mirror-symmetrical with respect to a plane of
symmetry and has a predefinable ratio of height to width, or an
asymmetrical trajectory with a non-mirror-symmetrical profile which
deviates from an elliptical shape or egg shape can optionally be
set, wherein the trajectory-setting system is configured to permit
at least three of the following settings independently of one
another: (i) an ellipse width of the trajectory between a minimum
value 0 for a straight cut and a maximum value relating to a
maximum height of the ellipse; (ii) horizontal shifting of the
entire trajectory between a minimum value and a maximum value;
(iii) inclination of the trajectory between a value 0 for a
vertically orientated trajectory, an inclination of the trajectory
in the direction of the feed device and an inclination of the
trajectory in the opposite direction; and (iv) shifting of the
trajectory in its entirety in the vertical direction.
[0016] I also further provide the spring winding machine that
manufactures helical springs by spring winding including a feed
device that feeds wire to a shaping device, wherein the shaping
device has at least one winding tool and at least one pitch die; a
cutting device that separates a finished helical spring from the
fed wire after termination of a shaping operation, wherein the
cutting device has a cutting tool which, by a cutting tool drive
system, can be moved along a predefinable closed trajectory; a
control device that controls the feed device, the shaping device
and the cutting device on the basis of an NC control program; and a
programmable trajectory-setting system that sets the shape and/or
position of the trajectory to be passed through by the cutting
tool, wherein a linear trajectory, an elliptical or egg-shaped
trajectory, which is mirror-symmetrical with respect to a plane of
symmetry and has a predefinable ratio of height to width, or an
asymmetrical trajectory with a non-mirror-symmetrical profile which
deviates from an elliptical shape or egg shape can optionally be
set, wherein the feed device is configured to continuously feed the
wire, and the cutting device has a cutting tool which can be driven
in rotation, and the spring winding machine is configured such that
the finished helical spring is separated from the feed wire by a
rotating flying cut.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] FIG. 1 shows a schematic overview illustration of an example
of a spring winding machine.
[0018] FIGS. 2 and 3 show enlarged views of components of the
shaping device and various adjustable trajectories for the cutting
tool.
[0019] FIGS. 4 to 6 show in schematic form various views of
components of the cutting device from FIG. 1.
[0020] FIG. 7 shows a view of a graphic operator interface which
assists the user in setting the trajectory.
[0021] FIG. 8 shows in 8A to 8E schematic views of various types of
cut.
[0022] FIG. 9 shows a plan view of components of another example of
a cutting device.
DETAILED DESCRIPTION
[0023] My spring winding machines have a programmable
trajectory-setting system to set the shape and/or position of the
trajectory to be passed through by the cutting tool. The
trajectory-setting system makes it possible to set different types
of cut in a flexible and simple way. In this context, a linear
trajectory (for a straight cut), an elliptical or egg-shaped
trajectory, which is mirror-symmetrical with respect to a plane of
symmetry and has a predefinable ratio of height to width, or an
asymmetrical, i.e., non-mirror-symmetrical, trajectory with a
profile which deviates from an elliptical shape or egg shape can
optionally be set. As a result of these setting options it is
possible, depending on the application, to bring about, inter alia,
expansion of the range of uses of the straight cut or of a
rotational cut, control the output rate (machine output), control
the cross section on the finished helical spring, control the
position of the cutting burr on the finished helical spring and/or
an increase in the service life of the cutting tools, in particular
in the case of the straight cut.
[0024] I employ a programmable trajectory-setting system, as a
result of which it is possible for an operator to predefine a large
range of different trajectories for the cutting tool without manual
interventions in the mechanical components of the cutting device
and to program the trajectories solely by control
interventions.
[0025] Preferably, the setting options are made possible by virtue
of the fact that the cutting tool drive system has a first drive,
which can be actuated by the control device and generates a first
movement of the cutting tool, and a second drive, which can be
activated by the control device independently of the first drive
and generates a second movement of the cutting tool superimposed on
the first movement. Different components of the cutting movement
can thereby be set in almost any desired ratios with respect to one
another.
[0026] The first movement is preferably a straight linear movement
in a first direction, and the second movement is preferably a
pivoting movement superimposed on the linear movement and is
transverse with respect to the first direction. It would also be
possible to superimpose two straight linear movements in directions
which are perpendicular to one another.
[0027] The cutting tool may be attached to a carriage which can be
moved linearly to and fro along a linear guide in a first
direction, and the linear guide may be attached to a pivoting
element which can pivot about a pivoting axle running substantially
perpendicularly to the first direction, wherein the first drive is
coupled to the carriage, and the second drive is coupled to the
pivoting element. As a result, a particularly rigid arrangement is
provided, which generates only relatively small tilting moments
even in the case of large cutting forces. It is also possible to
attach a pivoting element on a linearly moveable carriage.
[0028] The possibility of making the shape and/or position of the
cutting path (trajectory of the cutting tool) exclusively by
settings for the electric drives is used in one example of the
spring winding machine during programming of the trajectory in a
teaching process to approach manually one, two, three or more edge
points or disrupting contours and, as a result, to position the
trajectory in such that during later operation the trajectory
remains within these disrupting contours and no collisions can
occur, for example, with a winding tool or pitch die. For this
purpose, the control device is configured for teach-in programming.
The configuration is preferably such that in a programming
configuration the cutting tool can be positioned manually at one or
more positions in the region of a desired trajectory, the
coordinates of the positions can be stored in a memory of the
control device, a trajectory can be calculated using the
coordinates, and the cutting tool can be moved along the trajectory
in an operating configuration under the control of the control
device. The approached positions are usually disrupting points
defined as points which the trajectory must not overshoot.
[0029] The spring winding machine may be equipped with a camera
system which with its image field captures the region of the
shaping tools essentially from the front, i.e., parallel to the
direction of the desired spring axle. From the images captured in
this way it is possible to determine the position of the disrupting
contours using an image processor. This determination can be made
manually, semi-automatically or fully automatically. 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.
In this case, the control device may also be configured for
teach-in programming.
[0030] These and further features can arise not only from the
appended claims but also from the description and the drawings,
wherein the individual features are each implemented alone or
together in the form of subcombinations in one example and in other
fields, and can form advantageous examples which can be protected
in themselves.
[0031] The schematic overview illustration in FIG. 1 shows a number
of structural elements of a CNC spring winding machine 100
according to an example. FIGS. 2 to 6 show details.
[0032] The spring winding machine 100 has a feed device 110
equipped with feed rollers 112 and which can feed successive
portions of a wire 115 which comes from a wire stock, is guided
through a straightening device 114 and has a numerically controlled
advancing speed profile in the horizontal direction into the region
of a shaping device 120. Components of the shaping devices are
shown in FIGS. 2 and 3. The wire is guided on the outlet side
through a wire guide 116. The feed device can also be referred to
as a pull-in device and, accordingly, the wire advance can also be
referred to as a pulling in of the wire and the advancing speed as
the pull-in speed.
[0033] The wire is shaped to form a helical spring with the aid of
numerically controlled tools of the shaping device 120. The tools
include two winding pins 122, 124 arranged offset at an angle of
90.degree. and orientated in the radial direction with respect to
the central axis 118 or with respect to the position of the desired
spring axle and determine the diameter of the helical spring. The
position of the winding pins can be changed for the basic setting
of the spring diameter during set up in obliquely running
directions as well as in the horizontal direction to set up the
machine for different spring diameters. These movements can be
performed using suitable electric drives under the control of the
numeric controller.
[0034] A pitch die 130 has a tip orientated substantially
perpendicularly to the spring axle and which engages next to the
turns of the unwinding spring. The pitch die can be moved with the
aid of a numerically controlled adjustment drive of the
corresponding machine axle parallel to the axle 118 of the
unwinding spring (i.e., perpendicular to the plane of the drawing).
It is therefore also referred to as "pitch parallel." The wire
which is pushed forward during manufacture of the spring is pushed
away in the direction parallel to the spring axle by the pitch die
corresponding to the position of the pitch die, wherein the
position of the pitch die determines the local pitch of the spring
in the corresponding section. Changes in pitch are brought about by
axis-parallel movement of the pitch die during manufacture of the
spring.
[0035] The shaping device can have a further pitch die which can be
moved in vertically from below and which has a wedge-shaped die tip
inserted between adjacent windings when the pitch die is used. The
adjustment movements of this pitch die run perpendicularly to the
axle 118. This is therefore also referred to as "pitch
perpendicular." The pitch dies can be made to engage as required.
In a specific spring winding process typically only one of the
pitch dies is in engagement.
[0036] A numerically controllable cutting device 150 with a cutting
tool 152 is provided above the spring axle, the cutting tool 152
separating, after termination of a shaping operation, the
manufactured helical spring from the fed wire stock with a defined
working movement. The cutting tool is for this purpose moved such
that the cutting tool or its cutting edge 153 moves along a
predefined, closed trajectory (cutting path) in a plane which lies
perpendicular to the axle 118. FIGS. 2 and 3 show, for example, by
dot-dash lines a number of possible trajectories BK1, BK3 which are
also explained later in detail.
[0037] A mandrel 155 (trimming mandrel) serves as an opposing
element for the cutting tool and is located in the interior of the
unwinding spring and has an oblique cutting edge 156 which
interacts with the cutting tool 152 during the separation
process.
[0038] The cutting tool 152 is also referred to below as a cutting
blade 152. The trajectory of the cutting tool, which is also
referred to as a cutting curve, is defined here as that trajectory
travelled along by the cutting edge 153 of the cutting tool in the
working plane of the cutting tool which is perpendicular to the
central axle 118.
[0039] The spring winding machine or the cutting device is
configured such that the cutting path, that is to say the
trajectory of the cutting tool during the cutting movement, within
a structurally defined working range AB can be set to almost any
desired profiles and changed. The settings do not require
intervention by an operator in the mechanical components. Instead,
the settings can be programmed by the operator control unit 104 of
the spring winding machine using the control unit 102. The profile
of the trajectory can therefore be adapted in an optimum way to
different conditions during the manufacture of the spring.
[0040] With a freely programmable trajectory-setting system it is
possible to predefine the shape and/or the position of the
trajectory to be passed through by the cutting tool by programming
the control unit 102. It is possible in this context to set, in
addition to the cutting methods of the straight cut which can
occasionally also be set in conventional spring winding machines
(the cutting tool is moved to and fro along a linear trajectory)
and the so-called rotational cut in which, to cut the wire, the
cutting tool passes through an elliptical or egg-shaped trajectory
which is mirror-symmetrical with respect to a plane of symmetry,
also asymmetrical profiles of the trajectory which have a
non-mirror-symmetrical profile which deviates from an elliptical
shape or egg shape.
[0041] For this purpose, in an example, a cutting tool drive system
comprises two electric drives 165, 175 which can be controlled
independently of one another by the control unit 102 (cf. FIG. 6)
and which are coupled to the cutting tool 152 to transmit tool
movements. Both drives are electric servo drives. A first drive
generates a linear to-and-fro first movement of the cutting tool in
a first direction 154 which runs in the longitudinal direction of
the cutting tool 152. The second drive generates a second movement
of the cutting tool which is superimposed on the first movement,
and the second drive functions in the exemplary case as an
actuating drive which, during the linear to-and-fro movement of the
cutting tool in the first direction, additionally generates a
pivoting movement of the cutting tool, moved to and fro, about an
axis running perpendicular to the working plane. As a result of the
superimposition of the linear to-and-fro, essentially vertically
extending movement on the pivoting movement it is possible to
implement variable trajectories for the cutting tool.
[0042] As a result of the size and/or amplitude of the pivoting
movement it is possible, for example, to set the width of an
elliptical trajectory (measured perpendicularly to the first
direction 154). If no pivoting movement is carried out so that only
the linear movement remains, a straight cut can be carried out. As
a result of the size and/or amplitude of the linear movement, in
the case of a rotational cut, it is possible within the
structurally predefined limits to set the height of the elliptical
trajectory (measured parallel to the first direction), which
corresponds to the stroke in the first direction 154 in the case of
the straight cut. By predefining corresponding starting points of
the drives it is additionally possible to change the position of
the trajectory, for example, the position of an elliptical
trajectory to be able to position the trajectory in an optimum way
with respect to the trimming mandrel and the wire.
[0043] The first drive with its associated components should make
available a certain centrifugal mass so that sufficient kinetic
energy is made available for the cut. The second drive should have
high dynamics to permit rapid changes in movement when
necessary.
[0044] For the sake of further explanation, FIG. 2 illustrates the
position of the rest of the cutting tool 152. FIG. 3 shows a
situation in which the cutting edge 153 of the cutting tool is
located precisely at the impact point 117 on the wire during the
movement in the direction of the wire. The dot-dash lines represent
a number of possible paths of the cutting edge of the cutting tool,
that is to say the trajectories. Due to the mechanical conditions
of the example, the cutting edge can theoretically travel through
an approximately trapezoidal working range AB when the first and
second drives each carry out their maximum strokes. Within this
working range it is possible to map trajectories of almost any
shape and position, wherein, of course, the necessary dynamics
usually make certain trajectory profiles, for example, ones with
corners or sharp bends, impractical during execution of the cutting
movements. Within the working range it is, however, possible to
generate narrow or wide ellipses, straight paths, oblique paths,
shaped curves, laterally offset ellipses or other trajectories. As
a result, the profile of the cutting path can be adapted in terms
of control technology to the conditions.
[0045] A number of examples of particularly advantageous
trajectories under different production conditions are explained in
more detail below, for example, in relation to FIG. 8.
[0046] FIGS. 4 to 6 show various schematic views of components of
the cutting device 150 from FIG. 1, which permit different
trajectories to be flexibly set. An essentially rectangular
pivoting plate 160 is rotatably mounted on a horizontal pivoting
axle 161 on the vertical front wall 106 of the spring winding
machine 100. The to-and-fro pivoting movement is implemented by a
horizontally orientated pivoting shaft 162 which is driven by a
second drive 165 which serves as a pivoting drive. The pivoting
shaft 162 has at its front end an eccentric bolt 163 which bears a
link 164 guided in a rectangular recess of the pivoting plate 160
to be movable in the longitudinal direction of the pivoting
plate.
[0047] A linear guide 170 is provided on the front side of the
pivoting plate 160 facing away from the pivoting axle 161 and is
orientated in the longitudinal direction of the pivoting plate and
bears a carriage 171 to which a tool holder 155 for the cutting
tool 152 is attached. The cutting tool projects out of the tool
holder at the lower end. At the upper end, a connecting rod 172 is
provided in a pivotable fashion by a securing bolt, the connecting
rod 172 being infinitely adjustable in terms of its length and
being connected at its other end to an eccentric bolt 173 located
on the end side of a cutting shaft 174. The latter is driven by the
first drive 175.
[0048] The first and second drives, which are each formed by
electric servo drives, are actuated in principle independently of
one another, but in a coordinated fashion, by the control device
102. The "coupling" of the drives is not effected here in a
mechanical fashion but rather instead exclusively by software, that
is to say by the control program. This provides a high degree of
flexibility during generation of working movements of the cutting
tool.
[0049] The first drive 175 drives, via the cutting shaft 174, the
essentially vertical linear cutting movement of the carriage 171
which bears the cutting tool 152. The pivoting shaft 162 which is
driven by the second drive 165 functions, in contrast, merely as an
actuating drive and is activated intermittently, that is to say
generally does not carry out a 360.degree. rotation. The cutting
shaft 174 is, on the other hand, continuously operated in the same
rotational direction and with a varying rotational speed to make
available the necessary energy and speed for the separating
process. However, it would also be possible to intermittently
activate the cutting drive (first drive). This can be appropriate,
for example, if the height of the trajectory in the upward
direction is to be reduced compared to the maximum achievable
height.
[0050] The first drive 175 (cutting drive) and the second drive 165
(pivoting drive) can be actuated independently of one another so
that theoretically any desired superimpositions of the linear
movement in the first direction 154 and of the pivoting movement
superimposed thereon in the transverse direction are possible.
[0051] The pivoting element 160 can be secured in the vertical
position by a locking device which can be moved into or out of
engagement with the pivoting arm by machine commands, with the
result that the carriage 171 is moved exclusively in the vertical
direction. The locking device can have, for example, a bolt which
can be activated electrically or pneumatically and which can be
moved from behind (from the machine side) into a drilled hole on
the rear side of the pivoting plate. By virtue of the locking, the
arrangement becomes free of play in terms of the pivoting movement
and reinforcement of the structure occurs for the vertical cut so
that large cutting forces can be transmitted without excessive
loading of the components of the cutting device.
[0052] The trajectory-setting system of the example is configured
in a very user-friendly manner, and the complex settings for the
correct trajectory can therefore be performed intuitively even by
less experienced operators. FIG. 7 shows by way of example a view
of the operator control unit with a graphic operator interface
which assists the user during the setting operations. In the
rectangular graphic representation shown on the left, a symbol 155'
for the currently used trimming mandrel, a symbol 130' for the
holder of the currently used pitch die and a symbol 115' for the
wire are represented at the lower edge of the image. The tools 155
and 130 form in the exemplary case the relevant disrupting contours
which have to be taken into account during the configuration of the
trajectory of the cutting blade. They are illustrated in the
correct position and with the correct size ratio in the graphic
generated by the control unit 102. The obliquely running dashed
line in an extension of the oblique cutting edge (chamfer on the
trimming mandrel) helps during the correct setting of the cutting
gap. The cutting gap is defined here as the perpendicular distance
between the cutting edge or the dashed line and a tangent, running
parallel thereto, to the trajectory BK1 or BK4 at the impact point
117 on the wire. For excellent cutting results, this cutting gap
should generally be 30 to 70.degree. of the diameter of the
wire.
[0053] At the operator interface, switching buttons to set
trajectory parameters are made available to the operator to the
right next to the graphical representation. With the upper
switching button ELB it is possible to set the ellipse width
between a minimum value (0) and a maximum value (90) by activating
the arrow keys. These values respectively relate to a constant
height of the ellipse. When the lower limiting value ELB=0 is set,
a straight cut (linear to-and-fro movement of the cutting tool) is
therefore carried out.
[0054] The switching button VH below brings about horizontal
shifting of the entire closed trajectory between a minimum value
VH=0 and a maximum value by activating the arrow keys. This
horizontal displaceability of the trajectory makes it possible,
inter alia, to use identical tools (mandrel, diameter) for
different trajectories. If only the width of the ellipse were
adjustable, the middle of the trajectory would remain unchanged and
the impact point of the cutting tool on the wire would migrate away
from the mandrel or in the direction of the mandrel. The cutting
conditions would therefore generally worsen. Without lateral
adjustability the cutting blade would theoretically have to have a
somewhat different cutting geometry for each trajectory.
[0055] It is possible to provide that the adjustment of the ellipse
width and the adjustment of the horizontal position of the
trajectory are linked by software such that only parameter
combinations which do not move the position of the impact point, or
only do so slightly, so that an excellent cut remains possible can
be set. If appropriate, a warning signal can be generated when
parameters do not match one another sufficiently well.
[0056] The inclination of the trajectory can be set by the
switching button N below. A value N=0 corresponds to a vertically
orientated trajectory (long half axis vertical), and in the case of
negative values the trajectory is tilted to the left, that is to
say in the pull-in direction, and in the case of positive values to
the right, in the direction of the winding pins. The switching
button VV below brings about displacement of the trajectory in its
entirety in the vertical direction. The value for the current wire
diameter is input with the lower switching button D. Other
configurations that in the end offer the same, equivalent or
similar setting possibilities are possible.
[0057] The setting possibilities are given only by way of example.
Individual setting possibilities can also be dispensed with
completely in variants. Setting possibilities can be implemented in
practice in different ways. Some or all of the parameters can, for
example, be input directly into the control software, with the
result that an operator interface with sliding controllers or the
like is not necessary. The vertical adjustment of the trajectory is
generally not programmed, but instead can be implemented by manual
adjustment of the length of the connecting rod. It is also possible
to store in a memory of the control device a number of predefined
trajectory basic types which are controlled, for example, with
respect to production speed or other parameters. These can then be
retrieved by the operator and, if appropriate, then finely adjusted
by changing individual parameters and adapted to the conditions of
the spring winding process which is currently to be set up.
[0058] In the text which follows, a number of selected types of cut
are explained with their specific application areas and properties
with reference to FIG. 8. If appropriate, part of the cutting tool
SW, part of the trimming mandrel DO, the end piece of the remaining
wire DR with the cutting burr SG and the trajectory BK of the
cutting edge of the cutting tool are shown schematically. The
various elements are shown in an exploded view in the vertical
direction for illustrative reasons.
[0059] The system can be set for a straight cut (FIG. 8A) in which
the cutting tool is moved only vertically and a cutting tool and a
trimming mandrel are each selected with a perpendicular cutting
edge. The ellipse width and the inclination are for this purpose
each set to zero. Advancing of the wire is stopped for the cut.
With this type of cut a cutting burr SG is typically produced on
the wire and is directed inward in the direction of the central
axis of the spring.
[0060] The system can also be set to a rotational cut or a rotating
elliptical cut (FIG. 8B). In this context, the cutting tool moves
on an elliptical trajectory with a horizontal movement component
and a vertical movement component, wherein a fixed height-width
ratio is set. The cutting tool which is used and the trimming
mandrel which is used may have an oblique cutting edge or chamfer
in this case. With this type of cut, the cutting burr is generally
directed in the winding direction of the wire, with the result that
the internal diameter of the spring is not limited, or hardly
limited. For this purpose, only the ellipse width ELB is set to the
desired value.
[0061] The example permits these types of cut, which are also
frequently made available with conventional spring winding
machines, with a range which is increased compared to the prior art
and with a simplified setting capability. The straight cut
described above (vertical tool movement in conjunction with the
blade and the trimming mandrel with a perpendicular cutting edge)
can be modified to form a modified straight cut (FIG. 8C). In this
context, a cutting tool and a trimming mandrel with a perpendicular
cutting edge are also used. However, the cutting tool does not move
exclusively vertically, but also has a slight horizontal movement
component, with the result that a narrow elliptical shape (with an
adjustable height-width ratio) is produced. A cutting burr mainly
directed inwardly in the direction of the central axis of the
spring is also produced. 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 from the
cutting edge and from the cutting surface on the wire, the cutting
tool is no longer in contact with the cut-off wire during the
return travel. As a result, the wear on the tool can be
considerably reduced. Typical ratios between the height and the
width of the essentially elliptical trajectory can be, for example,
5:1 to 30:1, in particular 12:1 to 25:1.
[0062] Furthermore, a large number of other variants of the
rotational cut are available. In the case of the "variably rotating
cut" type of cut (FIG. 8B), the pull-in of the wire for the cutting
operation is stopped. A blade (cutting tool) and a trimming mandrel
with oblique cutting edges are used. The cutting edge of the tool
moves along an ellipse with a variably adjustable height-width
ratio, typically in the case of relatively narrow to medium-width
ellipses. In this case, it is possible to operate with "pitch
perpendicular" or "pitch parallel". A cutting burr is produced
which is arranged essentially in the winding direction of the wire.
The cutting burr is therefore within the inner and outer envelope
curve of the spring, that is to say it does not project inwardly or
outwardly beyond the spring.
[0063] In the case of the "flying rotating cut" type of cut (FIG.
8D), the spring winding machine operates with continuous advancing
of the wire or pulling in of the wire in conjunction with a flying
rotating cut. In this context, the cutting tool moves with a
horizontal movement component and a vertical movement component on
an elliptical trajectory with a relatively wide ellipse, that is to
say relatively small height-width ratio. As a result, relatively
high horizontal components of the movement during the cut are
achieved. The cutting tool and trimming mandrel each have
corresponding oblique cutting edges. Operations are carried out,
for example, with a perpendicular pitch (lower pitch die).
Depending on the design, the revolution can be elliptical or even
circular. The revolving speed is normally non-uniform.
[0064] With this type of operation of the continuous advancing of
the wire with a rotating flying cut, the wire is continuously
advanced or pulled in with a constant or varying final advancing
speed. Therefore, the wire feed does not come to a standstill
during the production of a large number of successive helical
springs. As a result, the output rate is increased. If the
advancing of the wire runs constantly, the wire stock, which is,
for example, kept on a reel, does not have to be continuously
accelerated and braked. This also applies to the drives of the feed
device and the tools. As a result, the energy requirement per
spring is reduced compared to methods with a standing cut in which
the advancing of the wire has to be stopped for the cutting
process. In addition, there is no jerky pulling on the wire and no
stick-slip effect, as a result of which the quality of the
manufactured springs can be significantly increased compared to
methods with a standing cut.
[0065] In the "flying cut" mode of operation there is automatic
coordination of the movement speed of the cutting tool along the
trajectory with the pull-in speed of the wire such that the shape
of the trajectory is adapted to the revolving speed of the cutting
tool such that in a time interval starting before the cutting edge
penetrates into the wire until the cutting contact between the
cutting tool and the wire is eliminated the movement speed of the
cutting edge in the horizontal direction (essentially parallel to
the wire advancing direction) is higher than the wire advancing
speed. If that time interval in which the cutting tool is in
engagement with the wire is referred to as the "wire collision
region," then the cutting tool should be accelerated such that its
horizontal component (parallel to the wire advancing speed) is
already larger before the start of the cut than that of the wire
and does not drop below the speed of the wire again until after it
moves out of the wire. For this reason, in this mode of operation
flat elliptical trajectories with a relatively large width and
correspondingly large horizontal component of the movement speed
generally have to be set.
[0066] The elliptical paths of the cutting tool described here by
way of example constitute only a number of special shapes of the
theoretically possible trajectories. The curve BK3 in FIG. 2
constitutes one example of an asymmetrical, controlled trajectory
shape with a finite height-width ratio. With this curve the same
advantages are obtained during the cut as with an elliptical curved
path BK1, but less space is required for the pitch die 130, with
the result that such trajectory shapes can be useful particularly
in the case of restricted conditions in the region of the shaping
tools. A large number of other path shapes are possible, for
example, even a flattened ellipse in the region of the chamfer on
the trimming mandrel (FIG. 8E). The cutting path can, for example,
be configured such that the flattened part runs parallel to the
chamfer on the trimming mandrel with a largely linear profile. By
suitable deformations, it is possible to set a large number of
useful asymmetrical trajectory shapes on the basis of the basic
shape of the ellipse or the egg shape.
[0067] Restrictions on the theoretically possible trajectories are,
on the one hand, caused by disrupting edges or collision points
with other tools such as winding fingers or pitch dies and, on the
other hand, are conditioned by the limits of the dynamics or
efficiency of the drive motors. These peripheral conditions can be
taken into account, inter alia, in a method variant in which
teach-in programming takes place. In this method variant, the
potential collision points in the region of the shaping tools are
approached manually with the cutting tool by the operator. When the
cutting tool is positioned at a collision point, this position is
transferred to the controller, that is to say communicated to the
controller, by an input by the operator. By using these positions,
the trajectory is then calculated automatically such that these
collision regions are excluded from the curved path which is
selected by the operator, or are not approached but are
bypassed.
[0068] My machines and methods permit different technical problems
to be addressed alternatively or cumulatively. On the one hand, the
range of use is expanded compared to conventional systems with a
straight cut and a rotating cut. Where possible, the output rate
and/or the machine output can also be controlled. In many cases,
the cross section at the cut wire is controlled. Furthermore, the
position of the cutting burrs remaining on the wire can be
controlled with respect to the intended use or further processing
of the springs. Not least, suitable settings can increase the
service life of the cutting tools, in particular in the case of the
straight cut.
[0069] By setting the position and inclination of the trajectory or
curved path during the cutting process, that is to say while the
cutting tool is in contact with the wire, the inclination of the
cutting edge on the wire can be determined. Furthermore, by these
setting possibilities it is possible to determine the inclination
or position of the remaining cutting burr. During the modified
straight cut (narrow ellipse) the cutting edge is treated gently
and chipping is prevented since the lateral moving away of the wire
edge after completion of the cut relieves the cutting tool of
lateral transverse forces caused by the wire.
[0070] Thanks to the possibility of programming the various
trajectories, these advantages can be set much more easily, without
mechanical intervention at the spring winding machine, than in
conventional spring winding machines which had a possibility of
setting different trajectories.
[0071] FIG. 9 shows a different structural example of components of
the cutting device which likewise provides all the setting
possibilities described above. The cutting tool 952 which is
secured by a tool holder is also mounted on a carriage 971 guided
in a linearly movable fashion by a linear guide 970. The linear
guide is mounted on a plate-shaped pivoting element or a pivoting
plate 960 rotatably mounted on a horizontal pivoting axle which is
attached to the vertical front wall of the spring winding machine.
Two separate drives which can be actuated independently of one
another by the control device 902 are provided for the linear
movement and the pivoting movement. A first drive 975 drives the
horizontal cutting shaft 974, which has at its end side an
eccentric bolt rotatably mounted in a link. The link is guided in a
recess in the carriage 971 to be perpendicularly displaceable with
respect to the longitudinal direction of the carriage. In this way,
rotation of the cutting shaft brings about an up-and-down movement
of the carriage 971 in the first direction 954, i.e., in the
longitudinal direction of the pivoting element 960. The to-and-fro
oscillating pivoting movement of the pivoting element is brought
about by the second drive 965 which drives a pivoting shaft 962 in
an intermittent fashion or to and fro. The pivoting shaft 962 has
on its end side an eccentric bolt rotatably mounted in a link which
is guided in a recess in the pivoting element 960 to be movable in
the longitudinal direction thereof.
[0072] In this example, the pivoting shaft 962 is therefore
arranged above the cutting shaft 974. In contrast to this, the
arrangement in the example in FIGS. 4 to 6, where the cutting shaft
is seated above the pivoting shaft, is reversed. These mechanical
components of the cutting tool drive system can therefore be
configured and arranged with respect to one another in different
ways as a function of the available installation space and of other
requirements.
* * * * *