GB1561839A - Apparatus for continuously measuring the length of a flexible elongate member - Google Patents

Description

(54) IMPROVED APPARATUS FOR CONTINUOUSLY MEASURING THE LENGTH OF A FLEXIBLE ELONGATE MEMBER (71) We, BICC LIMITED, a British Company of 21 Bloomsbury Street, London, WClB 3QN, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to apparatus for continuously measuring the length of an electric cable or cable core, a bare or insulated wire or other flexible elongate member as the member is travelling in the direction of its length, all such flexible elongate members hereinafter, for convenience, being included in the term LL core ".

A known apparatus for continuously measuring the length of an advancing core comprises three freely rotatable indentical measuring wheels which are geared together and are so resiliently mounted that their axes of rotation intersect to form the sides of a substantially equilateral triangle and that their peripheral surfaces define a passage through which the advancing core can be drawn, the arrangement being such that the advancing core passing between and in contact with the peripheral surfaces of the measuring wheels causes the wheels to rotate. The measuring wheels are operatively connected to counting means common to fne wheels and the length of the core that has passed through the apparatus is determined by this counting means.Although the accuracy of this apparatus is satisfactory for cores travelling at relatively low speeds, we have found that for cores travelling at speeds greater than 1000 metres/minute, the amount of slip that occurs between the measuring wheels and the advancing core is such tbat the reading of the counting means is insufficiently accurate. The apparatus is mechanically complex and heavy and it is believed that the slip that occurs when the length of a core travelling at high speed is being measured is due to the high inertia of the apparatus and to the frictional drag.

It is an object of the present invention to provide simple and inexpensive apparatus for continuously measuring the length of a core as the core travels in the direction of its length along a substantially rectilinear axis, which apparatus can be used to measure accurately the length of a core when travelling at a speed up to 2000 metres/ minute.

According to the invention the apparatus comprises a freely rotatable measuring wheel operatively connected to counting means and adapted to be rotatably driven by the advancing core and, for urging the advancing core against the peripheral surface of the measuring wheel, two freely rotatable rollers which are rotatably supported independently of and are urged by pressure means towards the measuring wheel, the axes of rotation of the pressure rollers lying in a substantially common plane, inclined to one another, and being so arranged with respect to one another and to the axis of rotation of the measuring wheel that the core advancing along said substantially rectilinear axis is constrained by the pressure rollers to travel in continuous contact with the peripheral surface of the measuring wheel.

Preferably the noint of intersection of the axes of rotation of the pressure rollers lies in a plane normal to the axis of rotation of and passing through the measuring wheel. Preferably, also, the angles at which the axes of rotation of the pressure rollers are inclined to the axis of rotation of the measuring wheel are substantially equal.

The angle of intersection of the axes of the pressure rollers is preferably in the range 60 to 90 , the preferred angle being approximately 70 . Since the peripheral surfaces of the pressure rollers are inclined at acute angles to the peripheral surface of the measuring wheel, a core entering the passage defined by these peripheral surfaces is constrained towards the centre of the peripheral surface of the measuring wheel, the apparatus thereby providing an effective self-centring action on an advancing core.

Since a core will be constrained to travel in contact with the central portion of the peripheral surface of the measuring wheel, the measuring wheel may be substantially thimler than the pressure rollers and marginal portions of the peripheral surface of the measuring wheel may be bevelled, thereby reducing the weight, and hence inertia, of the measuring wheel.

With a view to reducing further the weight and inertia of the apparatus, preferably each of the freely rotatable pressure rollers is rotatably supported independently of the other and the pressure rollers are so mounted that they are urged towards the measuring wheel by pressure means common to both rollers. Preferably the pressure rollers are mounted on an arm that is pivotable about an axis substantially parallel to the axis of rotation of the measuring wheel. The pressure means may be a spring or springs or may be a pneumatically or hydraulically operated piston working in a cylinder.

The counting means operatively connected to the measuring wheel may take any convenient form: counting means that are especially suitable include those operated by optical, electromagnetic, capacitive and mechanical pick-offs. It is preferred to employ counting means that will not only operate to detect a continual increase in the length of core passing through the apparatus but that will also operate to detect a continual decrease in the length of core that has passed through the apparatus should the direction of travel of the core be temporarily reversed. Any suitable means of recording the length of a core may be employed, a digital device being preferred. The counting means may display the length of the core that has passed through the apparatus directly and it may provide a signal or signals when a preset length of the core has passed through the apparatus.The counting means may also provide a printout of the length of the core to have passed through the appaartus at which a particular event has occurred, for example, the position at which a core fault, which has been detected by a separate fault detector, can be found. The support means of the pressure rollers preferably carries a switch which, when the trailing end of a length of core has passed through the apparatus and the pressure rollers move towards the measuring wheel, will close or open to disengage the counting means so that the counting means will not continue to operate whilst the measuring wheel is freely rotating after the trailing end of the core has passed.

The invention is further illustrated by a description, by way of example, of the preferred apparatus for continuously measuring the length of a core as it advances in the direction of its length with reference to the accompanying drawings, in which: Figure 1 shows a side view of the apparatus, and Figure 2 shows an end view of the apparatus.

Referring to the drawings the apparatus comprises a panel 1 on which is mounted a freely rotatable measuring wheel 2 operatively connected to a counting mechanism (not shown). Guide wheels 3 and 4 are supported on the panel on either side of the measuring wheel. Also supported on the panel is a spindle 5 on which is pivotally mounted an arm 6 carrying two pressure rollers 7, the arm 6 being urged towards the measuring wheel 2 by a coil spring 8. The axes of the pressure rollers 7 intersect in a plane normal to the axis of and passing through the measuring wheel 2, the angle of intersection of these axes being 70" and the axis of rotation of each pressure roller making an angle of 55" with the axis of rotation of the measuring wheel 2.During use of the Apparatus, a core advancing along a substantially rectilinear axis C is constrained to travel in contact with a central portion 9 of the peripheral surface of the measuring wheel 2 under the selfcentring action of the pressure rollers 7 caused by spring 8 acting on spindle 6 so that each roller 7 presses the core against the central portion 9 of the measuring wheel 2.

The apparatus is of light but robust construction and is suitable for in-line use; it may be either in the form of a freestanding unit or mounted on a base plate for incorporation in the control panel of a cable-making or other machine.

The apparatus in accordance with the invention is suitable for measuring the length of cores of circular or non-circular cross-section including bare and flat wire; it can be used to measure the length of a core of a diameter as small as 0.8 mm travelling at any speed up to 200 mitres/ minute. The measuring error will usually be less than t 0.2 per cent.

WHAT WE CLAIM IS:- 1. Apparatus for continuously measuring the length of a core as hereinbefore defined as the core travels in the direction of its length along a substantially rectilinear axis comprising a freely rotatable measuring wheel operatively connected to counting

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (14)

**WARNING** start of CLMS field may overlap end of DESC **. surfaces of the pressure rollers are inclined at acute angles to the peripheral surface of the measuring wheel, a core entering the passage defined by these peripheral surfaces is constrained towards the centre of the peripheral surface of the measuring wheel, the apparatus thereby providing an effective self-centring action on an advancing core. Since a core will be constrained to travel in contact with the central portion of the peripheral surface of the measuring wheel, the measuring wheel may be substantially thimler than the pressure rollers and marginal portions of the peripheral surface of the measuring wheel may be bevelled, thereby reducing the weight, and hence inertia, of the measuring wheel. With a view to reducing further the weight and inertia of the apparatus, preferably each of the freely rotatable pressure rollers is rotatably supported independently of the other and the pressure rollers are so mounted that they are urged towards the measuring wheel by pressure means common to both rollers. Preferably the pressure rollers are mounted on an arm that is pivotable about an axis substantially parallel to the axis of rotation of the measuring wheel. The pressure means may be a spring or springs or may be a pneumatically or hydraulically operated piston working in a cylinder. The counting means operatively connected to the measuring wheel may take any convenient form: counting means that are especially suitable include those operated by optical, electromagnetic, capacitive and mechanical pick-offs. It is preferred to employ counting means that will not only operate to detect a continual increase in the length of core passing through the apparatus but that will also operate to detect a continual decrease in the length of core that has passed through the apparatus should the direction of travel of the core be temporarily reversed. Any suitable means of recording the length of a core may be employed, a digital device being preferred. The counting means may display the length of the core that has passed through the apparatus directly and it may provide a signal or signals when a preset length of the core has passed through the apparatus.The counting means may also provide a printout of the length of the core to have passed through the appaartus at which a particular event has occurred, for example, the position at which a core fault, which has been detected by a separate fault detector, can be found. The support means of the pressure rollers preferably carries a switch which, when the trailing end of a length of core has passed through the apparatus and the pressure rollers move towards the measuring wheel, will close or open to disengage the counting means so that the counting means will not continue to operate whilst the measuring wheel is freely rotating after the trailing end of the core has passed. The invention is further illustrated by a description, by way of example, of the preferred apparatus for continuously measuring the length of a core as it advances in the direction of its length with reference to the accompanying drawings, in which: Figure 1 shows a side view of the apparatus, and Figure 2 shows an end view of the apparatus. Referring to the drawings the apparatus comprises a panel 1 on which is mounted a freely rotatable measuring wheel 2 operatively connected to a counting mechanism (not shown). Guide wheels 3 and 4 are supported on the panel on either side of the measuring wheel. Also supported on the panel is a spindle 5 on which is pivotally mounted an arm 6 carrying two pressure rollers 7, the arm 6 being urged towards the measuring wheel 2 by a coil spring 8. The axes of the pressure rollers 7 intersect in a plane normal to the axis of and passing through the measuring wheel 2, the angle of intersection of these axes being 70" and the axis of rotation of each pressure roller making an angle of 55" with the axis of rotation of the measuring wheel 2.During use of the Apparatus, a core advancing along a substantially rectilinear axis C is constrained to travel in contact with a central portion 9 of the peripheral surface of the measuring wheel 2 under the selfcentring action of the pressure rollers 7 caused by spring 8 acting on spindle 6 so that each roller 7 presses the core against the central portion 9 of the measuring wheel 2. The apparatus is of light but robust construction and is suitable for in-line use; it may be either in the form of a freestanding unit or mounted on a base plate for incorporation in the control panel of a cable-making or other machine. The apparatus in accordance with the invention is suitable for measuring the length of cores of circular or non-circular cross-section including bare and flat wire; it can be used to measure the length of a core of a diameter as small as 0.8 mm travelling at any speed up to 200 mitres/ minute. The measuring error will usually be less than t 0.2 per cent. WHAT WE CLAIM IS:-

1. Apparatus for continuously measuring the length of a core as hereinbefore defined as the core travels in the direction of its length along a substantially rectilinear axis comprising a freely rotatable measuring wheel operatively connected to counting

means and adapted to be rotatably driven by the advancing core and, for urging the advancing core against the peripheral surface of the measuring wheel, two freely rotatable rollers which are rotatably supported independently of and are urged by pressure means towards the measuring wheel, the axes of rotation of the pressure rollers lying in a substantially common plane, inclined to one another, and being so arranged with respect to one another and to the axis of rotation of the measuring wheel that the core advancmg along said substantially rectilinear axis is constrained by the pressure rollers to travel in continuous contact with the peripheral surface of the measuring wheel.

2. Apparatus for continuously measuring the length of a core as hereinbefore defined as the core travels in the direction of its length along a substantially rectilinear axis, comprising a freely rotatable measuring wheel operatively connected to counting means and adapted to be rotatably driven by the advancing core and, for urging the advancing core against the peripheral surface of the measuring wheel, two freely rotatable rollers which are rotatably supported independently of and are urged by pressure means towards the measuring wheel, the axes of rotation of th pressure rollers lying in a substantially common plane, inclined to one another, and the point of intersection of the axes lying in a plane normal to the axis of rotation of and passing through the measuring wheel so that the core advancing along said substantially rectilinear axis is constrained by the pressure rollers to travel in continuous contact with the peripheral surface of the measuring wheel.

3. Apparatus as claimed in Claim 1 or 2, wherin the angles at which the axes of rotation of the pressure rollers are inclined to the axis of rotation of the measuring wheel are substantially equal.

4. Apparatus as claimed in any one of the preceding Claims, wherein the angle of intersection of the axes of the pressure rollers is in the range 60 to 90".

5. Apparatus as claimed in any one of the preceding Claims, wherein each of the freely rotatable pressure rollers is rotatably supported independently of the other.

6. Apparatus as claimed in any one of the preceding Claims, wherein the pressure rollers are so mounted that they are urged towards the measuring wheel by pressure means common to both rollers.

7. Apparatus as claimed in any one of the preceding Claims, wherein the pressure means is a spring or springs.

8. Apparatus as claimed in any one of Claims 1 to 6, wherein the pressure means is a pneumatically or hydraulically operated piston working in a cylinder.

9. Apparatus as claimed in any one of the preceding Claims, wherein the pressure rollers mounted on an arm that is pivotable about an axis substantially parallel to the axis of rotation of the measuring wheel.

10. Apparatus as claimed in any one of the preceding Claims, wherein the counting means will detect a continual decrease in the length of the core passing through the apparatus should the direction of travel of the core be reversed.

11. Apparatus as claimed in any one of the preceding Claims, wherein the counting means has an associated digital device for recording the length of the core that has passed through the apparatus.

12. Apparatus as claimed in any one of the preceding Claims, wherein the support means of the pressure rollers carries a switch which, when the trailing end of a length of core has passed through the apparatus and the pressure rollers move towards the measuring wheel, will close or open to disengage the counting means so that the counting means will not continue to operate whilst the measuring wheel is freely rotating after the trailing end of the core has passed.

13. Apparatus as claimed in any one of the preceding Claims, wherein the measuring wheel is substantially thinner than the pressure rollers.

14. Apparatus substantially as hereinbefore described with reference to and as shown in the accompanying drawings.