GB2289267A

GB2289267A - Unwinding coiled metal strip

Info

Publication number: GB2289267A
Application number: GB9508945A
Authority: GB
Inventors: Masaharu Tasaki; Masashi Sato; Keiichi Muraoka; Shinji Hasumi
Original assignee: Nippon Mining and Metals Co Ltd; Nippon Mining Co Ltd
Current assignee: Nippon Mining Holdings Inc; Eneos Corp
Priority date: 1994-05-12
Filing date: 1995-05-02
Publication date: 1995-11-15
Anticipated expiration: 2015-05-02
Also published as: GB9508945D0; KR0169548B1; GB2289267B; JP2678567B2; KR950031278A; JPH07303917A

Abstract

A method of unwinding a coiled strip from a coil or coils of a metal strip horizontally placed on a turntable, is characterized by disposing a feed roller 9 between the coil 8 and a machining facility and a contact type dancer roller 13 between the feed roller 9 and the coil 8; detecting variation in tension acting on the strip based on displacement of the contact type dancer roller to control the rotational speed of the turntable so that the tension of the strip at the position where the tension is detected falls within a predetermined range; and disposing a non-contact sensor 10 between the feed roller and the machining facility to detect displacement of the strip at the position of the non-contact sensor and to control the rotational speed of the feed roller so that the strip is fed into the machining facility at a constant velocity. <IMAGE>

Description

METHOD OF UNWINDING A COILED STRIP The present invention relates to a method of unwinding a strip material, and more particularly to a method of unwinding a strip from a continuous coil which is formed by connecting the ends of strips of a plurality of coils, thereby making it possible to successively unwind a continuous strip having an arbitrary length.

In general, a strip of a metal having desired characteristics and a thickness is manufactured from a metal ingot by repeatedly performing rolling and heat treatment. Although various surface treatments may be subsequently performed in some cases, the rolled material is finally slit with a slitter in a desired width to obtain strips. Each strip is then coiled such that the widthwise direction of the strip becomes parallel to the central axis of a coil to be formed and the slit edges are trued up, whereby a coil of a metal strip is manufactured. The coiled metal strip is thereafter used as a raw material in a machining facility where a surface treatment such as plating and coating, a plastic working using a press, or the like is performed to machine the strip. In this machining stage, it is essential to continuously uncoil the metal strip and unwind it from a coil. Accordingly, the stage of unwinding the strip is a crucial step which affects the productivity in the machining stage and the quality of products.

Conventionally, the following typical methods have been used to uncoil a metal strip: (1) a method using a vertical uncoiler, (2) a method using a horizontal uncoiler for stacked coils, (3) a traverse method, and (4) a method using a continuous coil, e.g. USP No. 4,022,396 and Japanese Patent Publication No. Hei 4-36766.

In the method using a vertical uncoiling device, coils need to be vertically set onto the uncoiling device, in a coil by coil manner as a reel for a projector is set. The strip is then unwound while rotating the coil. In this method, a new coil needs to be set onto the recoiler every time the previous coil has been completely used. Accordingly, a worker changes the orientation of each one of coils which are previously stacked horizontally on a pallet (a support base) to a vertical orientation to set it onto the uncoiling device. This operation is time-consuming, thereby considerably decreasing the work efficiency of the machining facility such as a press. In addition, the work of raising a heavy coil from the horizontal state and subsequently setting the coil onto the uncoiling device is dangerous. Since the machining facility needs to be stopped for setting the leading end of the strip into the machining facility whenever a new coil is loaded, the working efficiency of the machining facility goes down. Moreover, since the machining facility cannot continuously carry out processing over a length exceeding the length of one coil, the length of products is limited.

In the method using a horizontal uncoiler for stacked coils, coils stacked on a pallet (a support base) are placed on a turntable together with the pallet, and a coiled strip is unwound from the outer (or inner) side of coils, while rotating the turntable, such that the unwinding operation of the strip is effected from the uppermost coil toward the lowermost coil in a coil-by-coil fashion. This method greatly improves the work efficiency, because the coils stacked on the pallet can be loaded, together with the pallet, on the turntable without changing the orientation of the coils, unlike the method using a vertical uncoiling device.

However, this method basically has the same problem as in the method using a vertical uncoiling device. That is, whenever an unwinding operation for a coil is completed, the machining facility needs to be stopped for setting the leading end of the next coil into the facility, or whenever an unwinding operation gets close to completion, the tail end of the coil needs to be welded to the leading end of the next coil which is located beneath it.

In the traverse method, a plurality of slit strips are welded to form a long strip, which is then wound on a reel, as a thread is wound, from the left-hand end to the right-hand end, and then from the righthand end to the left-hand end. This operation is repeated to continuously wind the strip in layers. The strip on the reel is then unwound while rotating the reel. Although this method is advantageous in that a long continuous strip can be used, the operation for winding the strip onto the reel is troublesome and time-consuming. Moreover, if the strip is wound onto the reel improperly, the strip slides during transportation, thereby damaging the surface of the strip, and making it impossible to unwind the strip. Also, since the surface of the strip is touched by a strip wrapped around it, small scratches are formed on the surface by the edge of the outer portion of the strip. Accordingly, this method cannot be used in applications where there are strict requirement on the prescribed surface properties.

In the conventional method using a continuous coil, as shown in Fig.

2, a plurality of coils 1, 2, 3, etc. horizontally placed on a pallet 7 are loaded on a turntable 8 of an uncoiling device such that the direction of coiling varies in a coil-by-coil fashion, and the inner ends or outer ends of adjacent coils are connected with each other.

While rotating the turntable 8 in one direction, the strip is continuously unwound of the coils, from the uppermost one toward the lowermost one, passing through the joint portion between the inner ends or outer ends of coils. This method makes it possible to smoothly unwind a continuous coiled strip, which has no step at the joined portions, without generating scratches or distortion. In addition, it is not necessary to temporarily stop the machining operation. However, the position at which the strip is unwound from a continuous coil varies between the inner side and the outer side in each coil, and the unwinding position gradually varies. Accordingly, it is difficult to prevent the loosening of coil due to spring force of the metal strip, and bending of the strip when the metal strip is made of a thin and soft material. Therefore, it is considerably difficult to properly unwind the strip.

Since the above-described methods have many drawbacks in terms of workability, productivity, the quality of a metal strip, and the yield of the strip (ratio of the usable portion of the strip), these methods do not meet the operating requirements for uncoiling a metal strip.

In the above-described conventional methods, whether the axis of each coil is vertical or horizontal, the force acting on a strip or displacement of the strip is detected by a dancer roll to rotate a coil, thereby unwinding the strip.

In the conventional methods, since the rotation of a coil is controlled in an on-off manner based on a signal from a sensor, the coil is abruptly rewound, resulting in a large variation in the unwinding velocity. Accordingly, in the method using a horizontal stacked type uncoiler, for example, the coil loosens due to the spring force of the metal strip when the strip is rewound from the outer side of the horizontal coil, and the coil buckles when the strip is rewound from the inner side of the coil if the metal strip is made of a thin and soft material.

Since the sizes and mechanical characteristics of metal strips vary, uncoilers need to be adjusted accordingly. Especially if the rotational speed of a coil during the operation is constant, the radial position at which the strip is unwound varies as the unwinding operation proceeds, so that the rewinding velocity varies between the leading end and the tail end of the coil. This causes the problems of loosening of the coil and bending of the strip occur more often. Accordingly, development of a method has been recently desired in which loosening of a coil and bending of a strip do not occur.

The present invention has been accomplished in view of the abovedescribed circumstances, and an object of the present invention is to provide a method of unwinding a coiled strip in which a feed roller is disposed between a coil and a machining facility to maintain the feed velocity of the strip constant at the side of the machining facility, and the tension acting on the strip is controlled to have a constant variation and fall in a narrow range at a location where the strip is rewound from the coil, thereby preventing the occurrence of problems such as loosening of the coil and bending of the strip.

To achieve the above-mentioned object, the present invention provides a method of unwinding a coiled strip from a coil of a metal strip horizontally placed on a turntable, and a method of unwinding a coiled strip from a continuous coil formed by a plurality of coils of a metal strip horizontally placed on a turntable, wherein the direction of coiling varies in a coil-by-coil fashion, the inner ends or outer ends of adjacent coils are connected with each other, and the plurality of coils are stacked with their rotational axes aligned, a feed roller is disposed between the coil and a machining facility, a contact-type dancer roller is disposed between the feed roller and the coil, variation in tension acting on the strip is detected based on displacement of the contact-type dancer roller so that the rotational speed of the turntable is controlled in order that the tension of the strip at the position where the tension is detected falls within a predetermined range, and a non-contact sensor is disposed between the feed roller and the machining facility to detect displacement of the strip at the position of the noncontact sensor and to control the rotational speed of the feed roller so that the strip is fed into the machining facility at a constant velocity.

Next, the action of the present invention will be described in relation to the method of unwinding a coiled strip from a coil of a metal strip horizontally placed on a turntable, and the method of unwinding a coiled strip from a continuous coil formed by a plurality of coils of a metal strip horizontally placed on a turntable, wherein the direction of coiling varies in a coil-by-coil fashion, inner ends or outer ends of adjacent coils are connected with each other, and the plurality of coils are stacked with their rotational axes aligned. A feed roller is disposed between the coil on the turntable and a machining facility, and a contact-type dancer roller is disposed between the feed roller and the coil. Since the contact-type dancer roller displaces in accordance with variation in the tension acting on the strip, the variation in the tension can be detected based on the displacement e to control the rotational speed of the turntable so that the tension of the strip at the position where the tension is detected falls within a predetermined range. Also, a non-contact sensor is provided between the feed roller and the machining facility to detect displacement of the strip at the position where the non-contact sensor is provided and to control the rotational speed of the feed roller based on the calculated value so that the strip is fed into the machining facility at a constant velocity.

Accordingly, the coiled strip can be unwound without causing the problems of loosening of the coil and bending of the strip.

These and other objects, features and advantages of the invention will become more apparent upon making reference to the following detailed description and from the drawings.

Any variations and modifications all revert to the invention if they are not departing from the spirit of the invention.

Fig. 1 is a perspective view of the present embodiment.

Fig. 2 is an explanatory chart showing a method using a continuous coil.

An embodiment of a method of unwinding a coiled strip according to the present invention will now be described with reference to the accompanying drawings.

The present embodiment shown in Fig. 1 employs a method using a horizontal stacked type uncoiler, in which a strip is unwound from the outer side of a coil. The coil 1 is placed horizontally on a turntable 8. A strip P is unwound of the coil 1 from its outer side and is fed in an X-direction indicated by an arrow toward a press or other machining facilities not shown. The metal strip has a width of 9-45 mm, and each coil has an outer diameter of 500-1150 mm and an inner diameter of 200 400 mm. The number of successive coils is 2 to 20, and the inner ends or the outer ends of adjacent coils which are wound in the clockwise direction or in the counterclockwise direction are joined so as to be continuous with each other. It should be noted that Fig. 1 shows only a single coil 1 for simplifying the drawing.

For machining with a press and other machining facilities, the strip P should be fed at a constant velocity. Therefore, a non-contact sensor 10 using an infrared or laser beam is disposed between the feed roller 9 and an unillustrated machining facility. The non-contact sensor 10 detects the amount L of droop (displacement) of the strip P, based on which a target velocity is calculated at which the strip should pass through the detecting point. The feed roller 9 is controlled in accordance with the calculated value to feed the strip P into the machining facility so that the feed velocity at which the strip is fed into the machining facility is maintained constant.

The feed roller 9 includes a holding roller 11 which provides the feed roller 9 with a revolving effort for driving required to feed the strip P with a motor 12. A dancer roller 13 is provided between the coil 1 and the feed roller 9. When the strip 9 is pulled out by the feed roller 9, the anglee of an arm 14 of the dancer roller 13 varies in accordance with variation in the tension acting on the strip P. The varied angle 0 is detected by an angle sensor 16, while the turntable 8 is subject to a rotating control so that the angle always falls within a predetermined range, and the coil 1 is rotated at the controlled velocity to feed out the strip P.

In the present embodiment, the feed velocity is controlled by the feed roller 9 such that the feed velocity coincides with the velocity at the side of a machining facility such as a press. Accordingly, the variation in the feed velocity is very small. Also, since the feed roller 9 and the holding roller 11 prevent variation in the tension from being transmitted from the side of the machining facility to the side of the coil 1, variation in resistance against the rewound strip, which may cause loosening of the coil and buckling of the strip, appears as variation in the tension acting on the strip between the coil 1 and the feed roller 9. Since such variation can be easily detected based on the displacement of the dancer roller 13, the tension acting on the strip P can be controlled to fall within a predetermined range by finely regulating the motor 15 and by controlling the rotational speeds of the feed roller 9 and the turntable 8. Accordingly, abnormal states such as loosening of the coil and buckling of the strip can be completely prevented regardless of the kind of metal forming the strip P, the size of the strip P, the machining velocity, and the like.

As described above, in the present invention, variation in tension acting on a strip is detected by a contact-type dancer roller to control the rotational speed of a turntable such that the tension of the strip between the feed roller and the coil falls within a predetermined range.

Also, a non-contact sensor is provided to detect the feed speed of the strip between the feed roller and a machining facility to control the rotational speed of the feed roller such that the strip is fed into the machining facility at a constant velocity. Accordingly, it is possible to unwind a strip from coils having various shapes while preventing the occurrence of abnormal states in which a coil loosens due to the spring force of the metal strip, or in which a metal strip made of a thin and soft material buckles or the like due to the material characteristics when the strip is unwound from the inner side of the coil.

In addition, even in the case where a continuous strip having an arbitrary length is successively unwound of a continuous coil in which ends of strips of a plurality of coils, not shown, placed horizontally in turn on a turntable 8 are connected, it is possible to considerably reduce problems as reduced in the above-described embodiment, such as loosening of a coil and buckling of a strip which would otherwise occur when the strip is sequentially and successively unwound from the inner sides and the outer sides of the coils alternately, resulting in a considerable improvement of workability in unwinding a coiled strip.

Claims

1. A method of unwinding a coiled strip from a coil of a metal strip horizontally placed on a turntable, characterized by disposing a feed roller between the coil and a machining facility and a contact-type dancer roller between said feed roller and the coil, detecting variation in tension acting on the strip based on displacement of said contact-type dancer roller to control the rotational speed of the turntable so that the tension of the strip at the position where the tension is detected falls within a predetermined range, and disposing a non-contact sensor between said feed roller and the machining facility to detect displacement of the strip at the position of the non-contact sensor and to control the rotational speed of said feed roller so that the strip is fed into the machining facility at a constant velocity.

2. A method of unwinding a coiled strip from a continuous coil which is formed by a plurality of coils of a metal strip horizontally placed on a turntable, wherein the direction of coiling varies in a coil-by-coil fashion, the inner ends or outer ends of adjacent coils are connected with each other, and the plurality of coils are stacked with their rotational axes aligned, characterized by disposing a feed roller between the coil and a machining facility and a contact type dancer roller between said feed roller and the coil, detecting variation in tension acting on the strip based on displacement of said contact type dancer roller to control the rotational speed of the turntable so that the tension of the strip at the position where the tension is detected falls within a predetermined range, and disposing a non-contact sensor between said feed roller and the machining facility to detect displacement of the strip at the position of the non-contact sensor and to control the rotational speed of said feed roller so that the strip is fed into the machining facility at a constant velocity.

3. The method of unwinding a coiled strip according to Claim 1 or 2, characterized in that said feed roller is combined with a holding roller as well as connected with a motor which provides a revolving effort for driving to feed the strip, and is subject to control of the rotational speed with said motor.

4. The method of unwinding a coiled strip according to Claim 1 or 2, characterized in that said contact-type dancer roller is connected with said motor while being supported by an arm, said arm being connected with an angle sensor, and detects with said angle sensor any varied angle of said arm which varies in accordance with variation in tension acting on a strip.

5. The method of unwinding a coiled strip according to Claim 3, characterized in that control of the rotational speed of a turntable as well as fine adjustment of said motor with which said contact-type dancer roller is connected are performed.

6. The method of unwinding a coiled strip according to Claim 4, characterized in that control of the rotational speed of a turntable as well as fine adjustment of said motor with which said contact-type dancer roller is connected are performed.