GB2072152A

GB2072152A - Strip tensioning means

Info

Publication number: GB2072152A
Application number: GB8108895A
Authority: GB
Original assignee: JAPAN DEV CONSULT
Current assignee: JAPAN DEV CONSULT
Priority date: 1980-12-23
Filing date: 1981-03-20
Publication date: 1981-09-30
Also published as: DE3111781A1; IT8148097A0; JPS56136748A; FR2479163A1; IT1144491B; JPS6229347B2

Abstract

A strip tensioner comprises one or more tension inducers (5) disposed on one or both sides of the strip (1), each tension inducer (5) comprising a non-rotatable presser (2), a frame (14) for holding the pressing element (2) firmly, without rotation, and a contact loop (3) passed around the presser (2) and capable of rotating with its internal surface sliding smoothly along the peripheral face of the presser (2) and its external surface rolling in contact with the strip (1). The tension imparted to the strip can be varied by pneumatic or hydraulic cylinders or springs. The external surface of the contact loop is made of soft nylon or rubber, and the internal surface of the loop is made of hard nylon, rubber or steel. The tensioner retards the strip without damaging its surface. <IMAGE>

Description

SPECIFICATION Strip tensioning means This invention relates to means and apparatus for tensioning strips slit from coiled material in the slitting lines of steel mills and metal manufacturing plants. More particularly, the invention relates to means and apparatus for tensioning and, at the same time, eliminating the variation in the tensions of said strips when winding same strips on a mandrel into individual coils.

It has been conventional practice to employ socalled roller bridles and tension pads for tensioning metal strips in winding same strips into individual coils on a mandrel.

In the practice employing roller bridles, the roller bridle, essentially an arrangement of rollers wherein one or more rollers come into contact with either coplanar sides of the strips and one or more said rollers on one or both coplanar sides of same strips are coupled to a braking means such as an electric generator or a mechanical retarding means, is located in advance of the strip winding mandrel such that the strips when passed through said arrangement of rollers become gripped and conveyed to same strip winding mandrel which also pulls the strips as they are being wound on it; the effect of said gripping being to tension the strips, and the adjustment of the tension to the desired intensity being done by varying the relative positions of said rollers and varying the grip.

One major defect in the practice employing roller bridles is that the strips do not get wound on the mandrel as tightly wound coils; instead, the coils are loosely wound and assume different diameters so that, upon removal from the mandrel, they become deformed into telescopic and elliptic forms making uncoiling and transportation inconvenient. The reason for this is that, as the thickness in the direction of the width of the material from which the strips are slit is not uniform, being thick at the center and thin towards the edges, the strips when wound on the mandrel form coils of different diameters causing the peripheral speeds of the coils and then, in turn, the tensions with which the strips are wound on the mandrel to be different; the consequence being to make the coils loosely wound, particularly those near the ends of the mandrel.

Again, if the strips directed to regions close to the ends of the mandrel are tensioned to the respective requisite intensities, it occurs that the strips directed to the central region of the mandrel slip through the rollers of the roller bridle, causing scratches, dents, deformations and other defects in their surfaces, and the strips thus become unfit for merchandising.

In the practice employing tension pads, the tension pads, each single tension pad being for one strip and comprising two wooden pads disposed in opposed fashion as to sandwich a strip when same strip is passed therebetween, and pressing means provided to one or both said wooden pads for bringing one wooden pad close to the other and pressing the strip, are located in advance of the strip winding mandrel. The faces of the wooden pads coming into contact with the strip are lined with a material like felt, and tensioning of the strip occurs by the braking effect produced by the friction between the felt material and the strip while the strip is being pulled by the winding of the strip on the mandrel.

As evident from the above, with hitherto available means and practices, it has not been feasible to tension strips for winding on a mandrel without damaging the coiled strips with scratches, dents, deformations and other defects.

According to this invention a tensioning device for strip material being fed to a coil comprises one or more tension inducers each having a pressing element, a frame for supporting the pressing element non-rotatably, a loop contact element extending rotatably around the pressing element for engaging the side of the strip material and pressing means for biasing the or one of the pressing elements towards the strip material to tension it.

The invention provides a strip tensioning means whereby uniform tensioning of a single strip can be effected so that, upon winding on a mandrel, the coiled strip is free from the hitherto found damages and defects like surface scratches, dents, diametral disconformities and deformations.

Such a strip tensioning means also enables uniform tensioning of a plurality of strips can be effected so that, upon winding on a mandrel, the coiled strips are free from the hitherto found damages and defects like surface scratches, dents, diametral disconformities and deformations. The strip tensioning means is easy to operate and maintain, and effective for an economical strip winding.

Examples of devices constructed in accordance with the present invention will now be described with reference to the accompanying drawings in which: Figure 1 illustrates the mechanism involved in the present invention, (A) and (B) being respectively front and cross sectional views; Figure 2 illustrates one preferred embodiment of the present invention, (A) and (B) being respectively front and cross sectional views, and (C) being a partial sectional view of the tension inducer of the present invention; Figure 3 illustrates another preferred embodiment of the present invention, (A) and (B) being respectively front and cross sectional views; Figure 4 illustrates a partial sectional view of another embodiment of the pressing means shown in Figure 3; and, Figure 5 illustrates another preferred embodiment of the present invention, (A) and (B) being respectively front and cross sectional views.

The mechanism involved in the present invention will now be described.

Referring to Figure 1 , the tension inducers 5, each comprising a pressing element 2 which is of length equal to the width of the strip 1 to be tensioned, a contact loop element 3 passed around the pressing element 2 and a frame 4 for holding firmly, permitting no rotation, the pressing element 2, are provided with the pressing means 6 attached to the main frame F such that the tension inducers 5 are disposed on either sides of the strip 1 in opposed fashion and the resulting assemblage is capable of gripping and conveying the strip 1 when the strip is passed in between the tension inducers 5, same tension inducers are brought sufficiently close to one another by manipulating the pressing means 6 and the strip 1 is pulled externally as in the winding of same strip on a mandrel.The contact loop element 3 is capable of rotating characteristically with the internal surface thereof sliding smoothly along the peripheral face of the pressing element 2 and the external surface thereof rotating in contact with the strip 1 without slipping when same strip is pulled externally as mentioned. In the mechanism, the tensioning of the strip 1 occurs when the grip produced is sufficient to prevent any slipping between the external surface of the contact loop element 3 and the strip 1 while same strip is being pulled externally. The selection of a material that produces substantial friction as the material for the external surface of the contact loop element 3 and the providing of a suitable grip by manipulation of the pressing means 6 become therefore essential in tensioning the strip properly.

In this sense, the material preferred for the external surface of the contact loop element 3 is a material like soft nylon or soft rubber. The mechanism eliminates the occurrence of damages and defects in the strip, prevalent in conventional tensioning means, by preventing totally the strip 1 coming into contact with any rubbing surface or element. This has been made possible by having the contact loop element act as a separator preventing any contact between the pressing element 2 and the strip 1 and making only same contact loop element rub against or slide along the peripheral face of the pressing element 2. The selection of a material that produces least friction as the material for the internal surface of the contact loop element 3 becomes essential; and the material preferred here is a material like hard nylon or hard rubber.

The mechanism thus makes it possible to tension the strip 1 efficiently and without causing any damages and defects in the strip even if same is wound on a mandrel: the essential features contributing to this being the characteristic role piayed by the coc+si; loop elements 3 and the grip provided by the pressing means 6.

One example embodying said mechanism of the present invention is as follows.

Referring to Figure 2, the two tension inducers, one denoted by 10 and the other by 14, each comprises a plurality of pressing elements 7 the length of each of which is almost equal to the width of the strip 1 , the contact loop elements 8 possessing the same characteristics mentioned when describing the mechanism of the present invention and passed individually around each pressing element 7, and the frame 9. The tension inducer 10 is connected to the two pressing means 12 attached to the over-frame 11 and the tension inducer 14 is supported rigidly by the main frame 13 such that the whole assemblage is capable of gripping and conveying the strip 1 when same strip is passed in between said two tension inducers and pulled externally after bringing the tension inducer 10 sufficiently close to the tension inducer 14 by manipulating the pressing means 12.The over-frame 11 is provided with the guide means 1 5 to enable the frame 9 of the tension inducer 10 move vertically upwards and downwards and assume proper alignment with the tension inducer 14 when the pressing means 12 are manipulated to produce a grip.

To facilitate maintenance and inspection of the two tension inducers 10 and 14, one end of the over-frame 11 is pivotally connected to the main frame 13 by the pin 16, the other end fastened to same frame 13 by the bolts 1 7 and the oil hydraulic cylinder 18 linking the main frame 13 and the over-frame 11 is provided so that, by removing the bolts 1 7 and then actuating the oil hydraulic cylinder 18, the over-frame 11 can be pivotally tilted about the pin 16, exposing the pressing elements and the contact loop elements of the two tension inducers.

The contact loop elements 8 are of the same construction mentioned when describing the mechanism of the present invention; that is, the internal surface of each contact element 8 is formed of hard nylon or steel, and the external surface of soft nylon or soft rubber. One alternative for satisfying the functional requirement of the internal surface of the contact loop element is by lubrication, preferably selflubrication, of same internal surface. In the present embodiment, lubrication of the internal surfaces of the contact loop elements is easily effected by simply providing the necessary piping and supplying oil to the contacting regions of the pressing elements 7 and the contact loop elements 8.

Various devices can be conceived for the pressing means 12. The feature essential in any such device is that besides producing a grip, the device must also permit to vary the grip so that a grip effective in tensioning the strip without impairing the characteristic rotation of the contact loop elements as mentioned when describing the mechanism of the present invention can be obtained. The variation of the grip may be effected manually, or mechanically, employing fluid hydraulic cylinders, springs and the like in such fashion as to link the main frame 13 and the tension inducer 10.

To tension simultaneously a plurality of strips, the strip tensioning means described so far may be employed for each strip, obviously with the tension inducers 10 provided with the pressing means 1 2 to serve individually each strip, or alternatively, as shown in (C) of same Figure 2, each tension inducer may be made to possess a plurality of the contact loop elements 8 and a single pressing element of length equal to the sum of the widths of the contact loop elements 8 ((C) of said Figure 2 shows four tension inducers, each with two contact loop elements).

Another example of the embodiment of the present invention is as follows.

Referring to Figure 3, two tension inducers, one denoted by 23 and the other by 27 as shown in (B) of same Figure, and each comprising a plate-like pressing element 1 9 of breadth about the width of the strip 1, the contact loop element 21 passed around the plate-like pressing element 1 9 and the pulleys 20, one of which is provided with the tensioning means 28 for tensioning the contact loop element 21, and the frame 22 for holding firmly the pulleys 20, are provided.The tension inducer 23 is linked to the pressing means 25 attached to the over-frame 24 of the main frame 26, and the tension inducer 27 is attached directly to same main frame, such that the whole assemblage is capable of gripping and conveying the strip 1 when same strip is passed in between said tension inducers and pulled externally, after bringing same tension inducers sufficiently close to one another by manipulating the pressing means 25 as described in the previous embodiment.

The construction and other aspects of the contact loop element 21 and the pressing means 25 are analogous to those of the corresponding elements in said mechanism of the present invention.

One example of an adjusting means for varying the grip finely in the present embodiment will now be described.

Referring to Figure 4, the plate-like pressing element 1 9 is linked to the frame 22 of the tension inducer 23 by the guide rods 32, each of which is provided with the externally threaded adjusting bush 46 that can be screwed onto the frame 22, and the spring 29, so that by turning the adjusting bush 46 those parts of the contact loop elements 21 coming into contact with either sides of the strip 1 can be brought into proper contact with same strip to produce the desired grip without impairing the characteristic rotation of the contact loop elements 21 as mentioned previously. Also the guide rods have the lower ends threaded for erecting them firmly on the frame 22 by screwing onto same frame and the upper ends provided with the heads 31 for preventing the assembly from disintegrating.

One feature in this adjusting means is that the respective parts of the contact loop elements 21 are always maintained in proper contact with the strip 1 and any upward movement of the strip is nullified by the springs 29 when same strip is being passed in between the tension inducers.

In the strip tensioning means just mentioned, the desired grip is produced by first bringing the tension inducers close to one another by manipulating the pressing means 25 and then turning the adjusting bushes 46 as necessary.

Although it was mentioned that the pressing means 25 is provided to the tension inducer disposed on the top side of the strip, the configuration is not limited to that, and configurations where the pressing means is provided to the tension inducer disposed on the bottom side or those disposed on both sides of the strip may also be conceived. Fluid hydraulic and pneumatic cylinders too may be employed in place of the springs 29 in the adjusting means.

One other example of the embodiment of the present invention, which actually includes the elements and features in Figures 2 and 3 of the embodiments described previously, is as follows.

Referring to Figure 5, one tension inducer, denoted by 36, and comprising a pressing element 33 of length about the width of the strip 1 , a contact loop element 34 encircling the pressing element 33 and a frame 35 for holding firmly same pressing element permitting no rotation, is linked to the pressing means 38 attached to the over-frame 37 of the main frame 39, and another tension inducer, denoted by 44, and comprising two pressing elements 41, each of length about the width of the strip 1 and held firmly permitting no rotation by the outwardly extending brackets 40 of the main frame 39, and a contact loop element 42 passed around the two pressing elements 41 and pulled at the lower central region by the tensioning means 43 attached to the main frame 39, are provided.The assemblage is capable of gripping and conveying the strip 1 when same strip 1 passed in between said tension inducers and pulled externally after bringing the tension inducer 36 sufficiently close to the tension inducer 44 as mentioned hereinbefore.

The attachment of the tensioning means 43 to the main frame 39 is by screwing onto same main frame the externally threaded adjusting bush 46 that compresses the spring 47 in pulling the contact loop element 42 by the guide roller 45 provided at the fore end of same tensioning means.

The construction and other aspects of the contact loop elements 34 and 42 and the pressing means 38 are analogous to those of the corresponding elements in other embodiments described previously. The tension inducer 44 differs from the other tension inducers described so far in that the frame for holding the pressing elements 42 is formed by the two brackets 40 and the main frame 39; however, there is no particular significance in having the frame so formed except for the simple object of saving construction material. The purpose and the performance of this tension inducer are the same as those of other tension inducers described herein.

Fine adjustment of the grip is effected by turning the adjustment bush 46 of the tensioning means 43 so that a constant grip, with no occurrence of slipping between the strip 1 and the contact loop elements 34 and 42, becomes feasible. A constant grip, of course, produces a uniform tension in the strip, provided the external pull given to the strip is also uniform.

As evident from the foregoing descriptions, the present invention therefore enables to tension uniformly a single strip, or a plurality of strips, slit from coiled material such that each strip, upon winding on a mandrel, is free from the hitherto found damages and defects like surface scratches, dents, diametral disconformities and deformations; the features contributing to this being the gripping and conveying of the strip afforded by said tension inducers disposed on either sides of the strip and the pressing means provided to the tension inducers on one or both sides of the strip, the prevention of any sliding contact between the strip and the elements in the mechanism afforded by the characteristic rotation of said contact loop elements in said tension inducers, the fine adjustment of the grip afforded by the adjusting means in the tension inducers on one or both sides of the strip, and the constant grip afforded by said pressing means and adjusting means. The strip tensioning means of the present invention is also characterized by simple construction, easy operation and maintenance, and a tensioning involving low costs.

It is obvious that numerous modifications of the various embodiments will occur to those skilled in the art; and it should be understood that the spirit and scope of this invention is to be limited solely by the appended claims.

Claims

1. A strip tensioning means for tensioning strips slit from coiled material comprising one or more tension inducers disposed on either sides of said strip, each said tension inducer comprising a pressing element, a frame for holding firmly said pressing element permitting no rotation and a contact loop element passed around said pressing element and capable of rotating characteristically with the internal surface thereof sliding smoothly along the peripheral face of said pressing element and the external surface thereof rolling in contact with said strip, one or more pressing means provided to one or more said tension inducers on one or both sides of said strip for bringing the tension inducers on one side of said strip closer to those on the other side of same strip and means for bearing rigidly said pressing means and those tension inducers not provided with said pressing means such that the whole assemblage is capable of gripping and conveying said strip without impairing said characteristic rotation of said contact loop elements when said strip is passed in between said tension inducers and pulled externally after bringing the tension inducers on one side of said strip sufficiently close to those on the other side of same strip by manipulating said pressing means.

2. A strip tensioning means of claim 1 wherein said contact loop element is made taut by passing around two pulleys without impairing said characteristic rotation of same contact loop element.

3. A strip tensioning means of claim 2 wherein said pressing element is held stably by said frame, permitting only a reversible displacement and not rotation, employing springs.

4. A strip tensioning means of claim 2 wherein an adjusting means is provided in either of said two pulleys for tensioning said contact loop element without impairing said characteristic rotation of said contact loop element.

5. A strip tensioning means of claim 1 wherein, instead of providing said frames individually for each said pressing element, a common frame capable of holding stably, permitting no rotation, said pressing elements in their respective positions on each side of said strip is provided without impairing said characteristic rotation of said contact loop elements.

6. A strip tensioning means of claim 1 wherein each said tension inducer on one side of said strip is provided with two said pressing elements, instead of one, such that said two pressing elements additionally serve to maintain said contact loop element taut without impairing said characteristic rotation of same contact loop element.

7. A strip tensioning means of claim 6 wherein each tension inducer provided with two said pressing elements has the contact loop element tensioned by an adjusting means provided with a roller that pulls at a point same contact loop element without impairing said characteristic rotation of same contact loop element.

8. A strip tensioning means of claim 1, 2, 5 cr 6 wherein each said contact loop element is formed of two materials, one satisfying the functional requirement for the internal surface of said contact loop element and the other satisfying the functional requirement for the external surface of same contact loop element, in producing said characteristic rotation of said contact loop element.

9. A strip tensioning means of claim 1, 2, 5 or 6, wherein the functional requirement for the internal surface of said contact loop element is satisfied by lubricating same internal surface, in producing said characteristic rotation of said contact loop element.

10. A strip tensioning means for tensioning a plurality of strips slit from coiled material wherein a plurality of common frame tension inducers, each said common frame tension inducer being for one side of a single said strip as described in claim 5, are connected rigidly by one or more cross frames to form a single aggregate of tension inducers, pressing means are provided in one or more said cross frames of the aggregates of tension inducers on one or each coplanar side of said plurality of strips to bring the aggregate of tension inducers on one coplanar side of said plurality of strips closer to the aggregate of tension inducers on the other coplanar side of same plurality of strips, and means are provided for bearing rigidly said pressing means and that aggregate of tension inducers not provided with said pressing means such that the whole assemblage is capable of gripping and conveying said plurality of strips simultaneously without impairing said characteristic rotation of said contact loop elements when same plurality of strips is passed in between said aggregates of tension inducers and pulled simultaneously by an external means after bringing said aggregates of tension inducers sufficiently close to one another by manipulating said pressing means.

11. A tensioning device for strip material being fed to a coil, the device comprising one or more tension inducers each having a pressing element, a frame for supporting the pressing element nonrotatably, a loop contact element extending rotatably around the pressing element for engaging the side of the strip material, and pressing means for biasing the or one of the pressing elements towards the strip material to tension it.