WO2019015467A1

WO2019015467A1 - Apparatus and associated method for making a shaped sawing wire

Info

Publication number: WO2019015467A1
Application number: PCT/CN2018/093838
Authority: WO
Inventors: Wenxian HUANG; Kurt VAN RYSSELBERGE
Original assignee: Bekaert Binjiang Steel Cord Co Ltd
Current assignee: Bekaert Binjiang Steel Cord Co Ltd
Priority date: 2017-07-18
Filing date: 2018-06-29
Publication date: 2019-01-24
Anticipated expiration: 2020-01-18
Also published as: CN207615563U

Abstract

An apparatus for continually forming a shaped sawing wire comprises: a first pulley (110) for receiving a steel wire (102), a pair of forming wheels (112, 112') for forming the steel wire (102) into a single crimped wire (104), a second pulley (110') for orienting the single crimped wire (104) before going into the pair of forming wheels (112, 112') a second time after being guided over the first pulley (110), the axis of the first pulley (110), the second pulley (110') and the axis of the forming wheels (112, 112') are parallel the one to the other. The apparatus only uses a pair of forming wheels and that can save costs. A method to produce a shaped sawing wire is further disclosed.

Description

APPARATUS AND ASSOCIATED METHOD FOR MAKING A SHAPED SAWING WIRE

Description Technical Field

The invention relates to an apparatus for making shaped sawing wire that is used for cutting hard and brittle materials.

Background Art

A shaped sawing wire is a fine steel wire that has bends with segments in between connecting the bends. Particularly popular shaped sawing wires are wires that have received two deformations or crimps: one crimp is made in a first direction (e.g. called the X-axis) perpendicular to the axis of the shaped sawing wire (oriented along the Z-axis) . A flat waveform in the XZ plane results. This flat wave is subsequently crimped in a second direction, different from the first direction that is oblique to the XZ plane. By preference this second direction is perpendicular to the XZ plane e.g. along the Y-axis.

A procedure to make such wire is described in Chinese patent ZL98811553.0, CN1100175C. In the apparatus described in Figure 1 of that publication, the steel wire is guided straightforwardly in between two pairs of crimping wheels that are oriented mutually orthogonal to one another and are closely mounted to one another.

However, the shaped sawing wire and the apparatus to make the shaped sawing wire as described have certain drawbacks.

Regarding the shaped sawing wire: during use the more prominent crimp -the one with the larger amplitude -of both crimps in the shaped sawing wire has the tendency to block the rotation of the wire during use. As a result the wire tends to flatten during sawing.

Regarding the production apparatus: the wire tends to rotate when going from the first to the second pair of crimper wheels even when the pairs of crimper wheels are closely mounted to one another. Further, as two pairs of crimper wheels have to be used i.e. four crimper wheels, and those wheels wear during use regular replacement of the wheels is necessary which is expensive.

The inventors have therefore searched to other products and apparatus to overcome those problems.

Disclosure of Invention and two modes to carry out the invention

It is therefore a specific object of the invention to provide an apparatus that uses less crimping wheels and that can produce a shaped sawing wire that has no preferential direction in the crimps. It is a further object of the invention to provide for a method for producing a shaped sawing wire wherein only one pair of crimper wheels is needed to produce a double crimped shaped sawing wire.

The apparatus provided can be placed in-line of a wire drawing bench, is driven by the movement of the steel wire coming out of that bench and thereby continually forms the shaped sawing wire. Alternatively the apparatus can be placed on a winder with a pay-off spool and a take-up spool wherein the wire is driven by a capstan that pulls the steel wire through the apparatus or wherein the take-up spool is driven to pull the wire through the apparatus.

A first embodiment of the apparatus will be explained based on Figure 1.

First the steel wire 102 is received on a first pulley 110. This pulley has a flat surface for reasons that will become clear later on. The wire touches the first pulley 110 slightly in order to make it rotate.

The steel wire 102 is then guided through a pair of forming wheels 112, 112’. The forming wheels 112, 112’may take the form of rotatable disks on which pins are mounted perpendicular to the plane of the rotatable disk. The disks are mounted with the pins intermeshing. As the pins are round they result in a particularly gentle bending of the steel wire. Alternatively the forming wheels may be intermeshing gear wheels as described in the second embodiment explained hereafter. The forming wheels induce a flat waveform into the steel wire that is parallel to a plane perpendicular to the axes of the forming wheels which is called single crimped wire 104.

The induced waveform can be represented by a function f (z) whereof the value represents the deviation from the axis of the steel wire and varies between a maximum value of ‘+A’ and a minimum value of ‘-A’ over a wavelength ‘W’ . ‘z’ is the coordinate along the axis of the single crimped steel wire 104. As the waveform is periodic f (z+W) must be equal to f (z) for any value of ‘z’ .

Thereafter the single crimped steel wire 104 is guided to a second pulley 110’. Again the second pulley 110’has a flat surface. At entry of the second pulley, the single crimped wire 104 will rotate 90° around its axis in order to align the plane of the crimp with the flat surface of the second pulley 110’. The wire is then led back over the first pulley 110. Between second and first pulley the orientation of the single crimped steel wire 104’does not change. The first pulley 110 will keep the orientation of the single crimped wire before it is being fed in between the forming wheels for a second time. During the second crimping operation, the single crimped wire enters with the plane of the first crimp parallel to the axes of the forming wheels. When passing the forming wheels a second waveform f (z) is given to the wire with exactly the same amplitude and wavelength of the first crimp but now in the direction perpendicular to the first crimp e.g. in the direction of the Y-axis.

The apparatus is characterised in that the axis of the first pulley, the second pulley and the axes of the forming wheel are parallel the one to the other.

If now the single crimped wire 104’at the second entry of the forming wheels runs in phase with the teething of the forming wheels 112, 112’the wire will tend to rotate in the wheel and the deformation of the single crimped steel wire 104’will remain in one plane.

However, by inducing a phase difference ‘F’ between the first and second forming event the teeth will engage between the crimps of the first crimped wire and a three dimensional helix shape forms. For example the phase difference can be set to between 1W/8 and 3W/8 preferably to W/4. Upon projection on the XY plane perpendicular to the Z-axis, a convex closed shape will form with four corners that is described by the equations: x=f (z) and y=f (z+F) . The resulting shape of the shaped sawing wire is a ‘square helix’i.e. a helix of which the projection along the axis is a tetragonal with a pitch W. Hence the resulting wire 106 does not show a preferred direction as the crimps given in both directions are equal.

In order to control the phase difference the distance ‘Δ’ between the first pulley and second pulley must be adjusted in order to change the length difference between both wires. A displacement ‘dΔ’ of the wheels will result in a phase shift ‘F’ of ‘2×dΔ’ at the entry of the forming wheels.

In an alternative embodiment of the invention as depicted in Figure 2, the first and the second pulley are one and the same: 210. Here the same wire passes twice over the one pulley that has a flat surface. Again a straight steel wire 202 is fed directly to the first pulley 210. The wire is guided over one member of the pair of forming wheels 212 and is deformed by the second pair member 212’. In this case the forming wheels can be in the form of two intermeshing gear wheels 212, 212’of which the teeth are rounded and between which a gap remains of at least the diameter of the steel. Both measures are needed to prevent damage to the steel wire while passing the forming wheels. However the forming wheels can equally well be the discs with pins 112, 112’of the first embodiment. A single crimped steel wire 204 is thus obtained.

By guiding this single crimped steel wire over the flat surface of pulley 210 a 90° turn of the single crimped wire 204 around its axis is induced resulting in a turned single crimp wire 204’when exiting the pulley 210. Now the crimp lies in the plane of the pulley 210 ready to be fed into the pair of forming wheels 212, 212’. Upon exiting the forming wheels for the second time, a shaped sawing wire 206 that is in the shape of a square helix is formed, provided the distance ‘Δ’ between the axis of the pulley 210 and the axis of the first member of the pair of forming wheels 212 is set to a value that puts the crimp of the single crimped wire 204 out of phase with the teething of forming wheels 212, 212’. This can be achieved by adjusting the distance ‘Δ’ . Again the axes of the forming wheels are parallel to that of the guiding pulleys.

In a further preferred realisation of the two above embodiments the pair of forming wheels is provided with a synchroniser 114, 224. The function of the

synchroniser

114, 214 to synchronise the movement between the members of the pair of forming wheels 112, 112’or 212, 212’. When the pair of forming wheels are synchronised with half a tooth distance phase difference between them the maximum +A of the waveform f (x) will fall at W/4, while its minimum -Awill occur at 3W/4.

If the phase difference between the members of the pair of forming wheels deviates from the half tooth distance a skewed waveform may result. This on itself is not a problem. Note that the phase difference ‘F’ between first and second deformation will not alter as both deformations are made between the same pair of forming wheels and the distance ‘Δ’ can be well controlled.

Only when the phase difference between the members of the pair of forming wheels could vary along the length -i.e. the forming wheels turn unsynchronised -the form of the shaped sawing wire will also alter over the length of the wire. In order to prevent this varying shape the

synchroniser

114, 214 may be used. The synchroniser may be provided in a form described in WO 2015/054820 A1 wherein the first and second member of the pair of forming wheels are connected by a gear train.

The described apparatus only contains one pair of forming wheels. Forming wheels are particularly expensive as they have to be made from hard metals and polished in order not to damage the wire. Moreover, the forming wheels wear during their use and have to be regularly replaced. Having to use only one pair of forming wheels already cuts the cost of the wheels in half. Moreover, not much other wheels and guides are necessary to make the apparatus further reducing its cost.

In a further aspect of the invention a method to produce a shaped sawing wire is described. The method comprises the steps of:

a. Providing a steel wire 102, preferably a steel wire without preformation and of sufficient straightness;

b. Pulling the steel wire over a first pulley 210. The steel wire makes the first pulley 210 rotate;

c. Thereafter guiding the steel wire between a pair of forming wheels 212, 212’. Thereby a single crimped wire 204 is formed;

d. This single crimped wire 204 is guided over a second pulley 201’thereby turning the single crimped wire over 90° or a quarter turn which results in a turned single crimped wire 204’;

e. This single crimped wire 204 is then led over the first pulley for the second time;

f. This is followed by the step wherein the turned single crimped wire 204’is guided between the guiding wheels for a second time. The resulting wire is a double crimped shaped sawing wire 206 called ‘shaped sawing wire’ hereinafter;

g. The shaped sawing wire is finally wound on a spool.

The method can be implemented by means of the previously described apparatus.

Alternatively the shaped sawing wire is pulled through the apparatus by means of a driven capstan followed by winding on a spool.

In a preferred embodiment the axis of the first pulley, the second pulley and the axes of the forming wheels are all parallel the one to the other.

By preference the surface of the first pulley 210 and second pulley 210’is flat. In preferred embodiment of the method the axis to axis distance between the first and second pulley is adjustable thereby making the phase between the first and second crimping operation variable.

Brief Description of Figures in the Drawings

Figure 1 describes a first embodiment of the inventive apparatus;

Figure 2 describes a second embodiment of the inventive apparatus.

Like parts are indicated with the same unit and tens number while the hundred digit refers to the figure number.

Note that the steel wire 102 and the single crimped wire 104 have been slightly displaced with respect to the shaped sawing wire 106 in order to make the working of the apparatus clear. In reality these wires are in the same plane, parallel to the axis of the pulleys and forming wheels.

Claims

An apparatus (200) for continually forming a shaped sawing wire (206) comprising a first pulley (210) for receiving a steel wire (102) , a pair of forming wheels (212, 212’) for forming the steel wire into a single crimped wire (204) , a second pulley (210’) for orienting the single crimped wire (204’) before going into said pair of forming wheels a second time after being guided over the first pulley (210) ,

characterised in that

the axis of the first pulley, the second pulley and the axis of said forming wheels are parallel the one to the other.
The apparatus according to claim 1 (200) wherein the surface of the first and second pulley is flat.
The apparatus according to claim 1 or 2 (200) wherein the axis to axis distance between the first pulley (210) and the second pulley (210’) can be adjusted.
The apparatus (100) according to any one of claims 1 to 3 wherein the first and second pulley are one and the same (110) .
The apparatus (100) according to any one of claims 1 to 4 wherein the distance between the first pulley and the pair of forming wheels (112, 112’) can be adjusted.
The apparatus (100, 200) according to any one of claims 1 to 5 wherein the pair of forming wheels are synchronised by means of a synchroniser (114, 214) .
Method to produce a shaped sawing wire comprising the steps of:

- Providing a steel wire (102) ;

- Pulling said steel wire over a first pulley (210) ;

- Thereafter guiding said steel wire between a pair of forming wheels (212, 212’) thereby forming a single crimped wire (204) ;

- Thereafter guiding said single crimped wire (204) over a second pulley (210’) thereby turning the single crimped wire over a quarter turn resulting in a turned single crimped wire (204’) ;

- Thereafter guiding said turned single crimped wire (204’) over said first pulley (210) ;

- Thereafter guiding said turned single crimped wire (204’) between said pair of forming wheels (212, 212’) thereby forming a double crimped shaped sawing wire (206) ;

- Winding said shaped sawing wire (206) on a spool.
The method according claim 7 wherein the axis of said first pulley, said second pulley and the axis of said forming wheels are parallel the one to the other.
The method according to claim 7 or 8 wherein the surface of said first (210) and second (210’) pulley is flat.
The method according to any one of claims 7 to 9 wherein the axis to axis distance between the first and second pulley is adjustable.