GB2025299A

GB2025299A - Device for Cutting Metal Wire into Pieces

Info

Publication number: GB2025299A
Application number: GB7922845A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1978-07-03
Filing date: 1979-07-02
Publication date: 1980-01-23
Also published as: DE2926622A1; IT1099302B; IT7825276A0

Abstract

In a device for cutting metal wire into pieces which comprises a fixed bush 17 through which the wire is fed, a mobile knife 14 cooperating with said bush and having an open seat 15 for receiving the wire, a stop 33 axially spaced apart from said bush and a spring clamp 21 cooperating with said seat to retain the wire therein, a removable retainer 32 is positioned between the mobile knife 14 and the stop 33 to hold the wire against bending during the cutting operation. <IMAGE>

Description

SPECIFICATION Device for Cutting Metal Wire into Pieces This invention relates to a device for cutting metal wire, particularly iron wire, into pieces as used for example as the initial components in the production of screws, bolts and the like.

One of the main problems arising in this process is to separate the piece from the rest of the wire with a clean cut.

In known devices, the wire to be cut is normally fed through a bush which also acts as a fixed knife, until it is halted by its end striking a stop at a distance from said bush which determines the length of the piece to be cut, then a mobile knife cooperating with said bush and acting on the wire emerging therefrom is operated suddenly to cut the wire at the point in which it leaves said bush. In certain cases, the mobile knife can consist of a bar with its end comprising a half seat to partially receive the wire, and with which a spring clamp cooperates to retain the wire piece in the vicinity of the cutting zone. This type of cutting device known to the art has the disadvantage of not ensuring that the piece is cut cleanly from the rest of the wire, and in particular the cut is not perpendicular to the wire axis.This is due to the fact that in the first stage of the cutting operation, the material offers considerable resistance to cutting, so that the part of the wire projecting from the fixed bush and which is to form the future piece is bent in the direction of movement of the mobile knife.

It has also been attempted to obviate this disadvantage by locking the free end of the wire at said stop during cutting, but this arrangement has not solved the problem because in this case it produces bending of that part of the wire projecting from the bush, but in the reverse direction.

The drawback of a cut which is not perpendicular to the wire axis can be at least partly obviated by using a mobile knife in the form of a second bush similar to the one used for the fixed knife. However, this method gives rise to considerable constructional complications in the machine, as a suitable device must be provided for expelling the piece cut by the mobile bush, and a device for conveying the piece to the die. This system is also inconvenient and difficult when particularly short pieces have to be cut.

The object of the present invention is to provide a cutting device which does not have the aforesaid drawbacks, and which enables wire pieces of any required length to be separated from a continuous wire by a clean perfect cut perpendicular to the wire axis, without any constructional complications arising in the machine, and which can also be applied to existing machines.

This object is attained, according to the invention, by a cutting device of the type comprising a fixed bush acting as a fixed knife, through which the wire to be cut is fed, a mobile knife cooperating with said bush and comprising at its end an open seat to partly receive the wire to be cut as it leaves said bush, a spring clamp cooperating with said seat to retain the wire therein, and a stop spaced apart from said bush to determine the length of the wire piece to be cut, the device comprising between the mobile knife and relative clamp, and said stop, an additional removable retainer acting on the same side of that part of the wire to be cut as said clamp, and mobile together therewith and with the mobile knife.

Preferably, this additional retainer is constituted by the shaped end of a lever hinged to the member supporting the mobile knife, and advantageously the axis of hinging of said lever is parallel to the axis of the wire to be cut, and the plane containing these two axes passes through the point at which the end of the lever acts against the wire.

In one advantageous embodiment, said lever is retained by a spring in a working position in which its end acts as the retainer for the wire to be cut, and means are provided for rotating said lever about its hinging axis against the action of said spring, to free the wire piece when the cut has been made.

It has been found that with the aid of said additional retainer, that part of the wire to be cut is supported and prevented from bending, so giving a clean cut perfectly perpendicular to the wire axis.

One embodiment of the cutting device according to the invention is described by way of example hereinafter with reference to the accompanying drawings, in which: Figure 1 is a plan view partly sectioned on the line I-I of Figure 2, Figure 2 is an elevation in the direction of the arrow II of Figure 1, of the device before cutting, Figure 3 is a view similar to Figure 2, but after cutting, and Figure 4 is a section on the line lV-lV of Figure 2.

The device illustrated on the drawings comprises a member 10 rigid with a bar 11 supported slidably along its axis over a predetermined distance (from the position shown in Figure 2 to the position shown in Figure 3 and vice versa) in the frame 12. A knife 14 is fixed to the member 10 by a screw 13, and comprises, at that end projecting from the member 10, an open seat 15 for partly receiving the wire to be cut 16 which is fed through a fixed bush 17 (Figure 1), the front surface of which is in contact with the lateral surface of the knife 1 4 to constitute the fixed knife.

A support is mounted in a fixed position on the member 10, and supports internally, by means of an upper pivot 19, a first double arm lever 20 which at one end comprises a rod 21 cooperating with the seat 1 5 of the knife 14 and acting as a clamp for retaining the wire 16 therein, while at its other end there acts a spring 22 which reacts against the support 18 and tends to urge the end of the rod 21 towards the seat 1 5.

A second double arm lever 25 is supported in the support 18 by a pivot 23 and bearings 24 (see Figure 4), and at one end carries a rod 27 in a position adjustable by screws 26, whereas a spring 29 acts on its other end by way of a push rod 28 (Figure 3) which tends to keep the bottom of an adjustment screw 30 of the lever 25 resting against the support 18 (see Figure 2). The pressure exerted by the spring 29 is adjustable by means of a dowel 31.

When the free shaped end 32 of the rod 27 is in its working position (Figures 1, 2), it constitutes a retainer for retaining the wire 16 in a position close to the seat 1 5 of the knife 14 and the clamp 21, this position being between these members and an adjustable fixed stop 33 (Figure 1) for the free end of the wire 1 6. The adjustable distance between this stop 33 and the cutting plane (plane of contact between the bush 17 and knife 14) determines the length of the wire piece to be cut.

As can be seen in Figure 2, the axis of the pivot 23 about which the lever 25 can rotate, is parallel to the axis of the wire 1 6 to be cut, and when the lever 25 and the respective rod 27 are in their working position, these two axes lie in a plane passing through the point at which the shaped end 32 of the rod 27 acts against the wire 1 6 to retain it.

The lever 25 also carries a roller 34 rotatable about a pivot 35, and during the movement of the entire mobile unit carried by the bar 11 , this roller 34 is arranged to cooperate with a cam 36 fixed to the frame 12 which, when the wire is cut (Figure 3), causes the lever 25 and rod 27 to rotate against the action of the spring 29 in such a direction as to withdrawn the shaped end 32 of the rod 27 from the cut wire piece, so releasing it.

The operation of the device is apparent from the description.

Before cutting, the wire 1 6, which is fed through the bush 17 until it meets the stop 33, is retained not only in the seat 51 of the knife 14 by the clamp 21, but also by the shaped end 32 of the rod 17 in a position somewhat beyond the cutting zone. Because of this retainer, when the cutting operation begins (displacement of the mobile unit towards the left, with reference to Figures 1 and 2), the wire, which would tend to bend in the same direction as the direction of movement of the mobile knife 14, is firmly retained and immobilised, so that the cut is clean and perfectly perpendicular to the wire axis.

This immobilisation is aided by the fact that the reaction force of the retainer (shaped end 32 of the rod 27) acts in a plane passing through the axis of the rotational pivot 23 of the lever 25 carrying the retainer.

After the cut is made (Figure 3), the retainer is automatically withdrawn to free the cut wire piece.

The described device is susceptible to numerous modifications within the scope of the present invention, which basically consists of having provided, adjacent to the clamp for retaining the wire in its seat in the mobile knife, an additional retainer which opposes the tendency of the wire to bend during cutting.

Claims

1. A device for cutting metal wire into pieces, comprising a fixed bush acting as a fixed knife through which the wire to be cut is fed, a mobile knife cooperating with said bush and comprising at its end an open seat for partly receiving the wire to be cut as it emerges from said bush, a spring clamp cooperating with said seat to retain the wire therein, and a stop spaced apart from said bush to determine the length of the wire piece to be cut, and further comprising an additional removable retainer acting on the same side of that part of the wire to be cut as said clamp, and mobile together therewith and with the mobile knife, said retainer being positioned between the mobile knife and relative clamp, and the stop.

2. A device as claimed in claim 1, wherein the retainer is constituted by the shaped end of a lever hinged to a member carrying the mobile knife.

3. A device as claimed in claim 2, wherein the hinging axis of said lever is parallel to the axis of the wire to be cut when positioned in the seat in the mobile knife, and the plane containing the two axes passes through the point at which the shaped end of the lever supports and acts against the wire to be cut.

4. A device as claimed in claim 2, wherein a spring acts against said lever at the other end thereof to said open end, to maintain the lever in its working position.

5. A device as claimed in claim 4, wherein means are provided for adjusting the working position of the lever.

6. A device as claimed in claim 4, wherein means are provided for rotating said lever about its hinging axis against the action of said spring, to release the wire piece when the cut has been made.

7. A device for cutting metal wire into pieces constructed and arranged substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.