GB2144399A

GB2144399A - Strip or wire accumulator

Info

Publication number: GB2144399A
Application number: GB08319559A
Authority: GB
Inventors: James Arthur Langley
Original assignee: BEAM TUBES Ltd
Current assignee: BEAM TUBES Ltd
Priority date: 1983-07-20
Filing date: 1983-07-20
Publication date: 1985-03-06
Also published as: GB8319559D0

Abstract

A strip or wire accumulator includes a plurality of rotatable rollers (18-22) spaced from one another and with parallel axes of rotation, and a loop-forming strip or wire guide element (52-56) between and slightly below each adjacent pair of rollers. A loop chamber (12-16) extends substantially vertically downwardly beneath each guide element (52-56). The arrangement is such that the strip in the accumulator hangs freely in loops, one loop being in each loop chamber. Each chamber may be 10 metres in height. The accumulator is used to supply strip continuously to a downstream production unit whilst the feed coils (30) are changed. The loop sensors (5) are used to control the drives to rollers (18-22) and operate when the respective loop chambers are full. The stop switch (SW) in the entry chamber stops the downstream production unit when the accumulator is nearly exhausted. <IMAGE>

Description

SPECIFICATION Strip or wire accumulator This invention relates to a strip or wire accumulator.

Strip accumulators are known, see for example U.S. Patent Specification No. 3,258,212 published in June 1966. This discloses a method and apparatus for accumulating strip in which the strip is continuously withdrawn from the inside of a coil, fresh strip is intermittently fed to the outside of the coil, and during strip feed, the coil is rotated to build up strip on the outside, relatively loosely. The coil is held when strip is not being fed on, and the pulling-off during this phase tightens the convolutions of strip on the coil. In order to draw off strip from the centre of a coil, it will be realised that it is necessary to have some twist in the strip. For some applications, this is disadvantageous.Although in the patent document, this apparatus is said to be of low capital cost, in practice the Applicants have found that its presently-available commercial developments have a high capital cost, and still exhibit the disadvantage of some deformation in the strip.

In the art of wire drawing, it has been proposed to maintain loops of wire between adjacent drawing dyes. For example in British Patent 1,023,244, a pulley or guide wheel mounted on a spring urged pivoted arm forms a loop of wire between one die and the next. According to British Patent No.

1,533,089, published November 1978, in a wire drawing apparatus a loop of wire between adjacent wire drawing blocks controlled by first and second guide pulleys and a dancer pulley.

It is an aim of the present invention to provide a simple effective, and relatively inexpensive strip or wire accumulator.

According to the present invention, there is provided a strip or wire accumulator including a plurality of rotatable rollers spaced from one another and with parallel axes of rotation, a loop-forming strip or wire guide element between and slightly below each adjacent pair of rollers, and a loop chamber extending substantially vertically downwardly beneath each guide element, the arrangement being such that strip or wire in the accumulator hangs freely in loops, one loop being in each loop chamber.

According to an embodiment of the present invention, there is provided a strip or wire accumulator including a plurality of rotatable rollers arranged horizontally spaced from one another, (e.g. at substantially the same horizontal level) and with their axes parallel, the plurality including an entry roller and an exit roller, a looping roll between each pair of adjacent rollers, and a loading roll arranged in association with each roller except the exit roller, each of the loading rolls being arranged to define with its respective roller a nip through which the strip or wire passes, each loading roller being selectively drivable and each looping roller being located above a space (herein called a loop chamber) into which a loop of the strip or wire can fall, in use, under gravity.

According to an advantageous embodiment of the invention, each loading roll is driven via a clutch, and the clutch is controlled in response to a sensor located in a lower region of each loop chamber and below the looping roll which is immediately upstream of the respective loading roll, the sensor being arranged to give a signal upon the presence or proximity of strip or wire, the signal serving to initiate driving of the said loading roll.

A stop switch may be located in an upper region of the upstream (or entry end) loop chamber. This switch is positioned to be activated when the loop of strip or wire in the first (upstream) chamber is approaching its minimum possible hanging length.

In use, this normally occurs when the off-take of strip from the accumulator is faster than the feedin of strip, and the switch is arranged to stop the strip-using production process downstream of the accumulator. Any transducer capable of providing a signal in response to presence or proximity of the strip could be used as the stop switch.

In this specification, for the sake of brevity, the word strip will be used as meaning either strip or wire.

The invention will be better understood from the following non-limiting description of an example thereof given with reference to the accompanying drawing in which the single Figure is a diagrammatic cross-section through one example of strip accumulator according to the invention.

The illustrated strip accumulator includes suitable structure 10 defining strip loop chambers 12, 14 and 16. Although only three chambers are shown for simplicity of explanation, a practical apparatus could have any desired number. Each loop chamber could be of any desired height, e.g. 30 feet or 10 metres. The number and height of the loop chambers is chosen according to the maximum length of strip it is necessary to store in the accumulator.For example, in the case of a production process (e.g. the continuous formation of tube from strip) which consumes strip at 200 feet per minute, and in which it takes say 3 minutes to join the loading end of one coil of strip to the trailing end of a previous coil, the accumulator could be dimensioned to have a maximum capacity of 1200 feet of strip, and could in this instance consist of 20 loop chambers each of about 30 feet depth and each therefore accommodating about 60 feet of strip.

Referring to the drawing, the illustrated accumulator has a plurality of rollers including an entry roller 18, intermediate rollers 19, 20 and an exit roller 22 are mounted for free rotation about parallel axes. An entry guide roller 24 guides strip 26 from a clamp and weld station 28 to which it is fed from a supply coil 30 of strip. The coil of a strip 30 is suitably mounted for free rotation about an axis 32. A plurality of loading rolls 38, 39, 40 are located above the rollers 18, 19 and 20, to define respective nips through which the strip passes. Each loading roll is driven by a suitable motor via a clutch, not shown. A tension roll 42 defines a nip with exit roller 22, and a guide roller 44 guides the strip 26 to a machine (e.g. a tube mill or a stamping machine) where the strip is to be used.

A looping roll is located in an upper region of each loop chamber 12, 14, 16. These looping rolls are shown at 52, 54 and 56 respectively. They serve an important function in the present invention, as they cause the strip path between adjacent rollers (e.g. between 18 and 19) to loop downwardly. Consequently the strip automatically and necessarily falls under gravity into the loop chamber (as illustrated) when the linear rate of infeed of the strip at the nip between rollers 18 and 38 exceeds the linear rate of off-take from chamber 12 at the nip between rolls 19 and 39. Without the looping rolls 52, 54 and 56 the strip 26 would pass directly from one nip to the next and the loops in the chambers 12, 14 etc., would not be formed.

Each loop chamber has, in its bottom region, a sensor LS which is such as to emit a signal (e.g. an electrical signal) in response to presence or proximity of the strip 26. This signal shows that the relevant loop chamber is full, and that no more strip should be fed thereinto. A signal of this kind from the loop sensor LS 12, LS 14 or LS 16 as the case may be is arranged to actuate the clutch associated with the respective loading roll 39, the loading roll 40 or the tension roll 42, causing the relevant loading or tension roll to be driven so that strip is taken out of the relevant loop chamber. The entry loop chamber 12 has a stop switch SW therein, located in an upper region thereof. The switch SW is sensitive to, and emits a signal in response to, presence or proximity of the strip 26.This signal is used to stop the operation of a downstream stripusing production process, since it indicates that the store of strip in the accumulator is nearly exhausted. It will be realised that the switch SW is arranged to be triggered only in response to presence or proximity of the curved portion 26b of the loop of strip 26, and not in response to presence or proximity of the substantially vertical runs 26a and 26c. Though the switch SW is illustrated as supported by a sidewall 12a of the loop chamber 12, in practice it will be found more convenient to support it by a bracket extending into the chamber from an end wall of the chamber.

In operation, the strip is threaded through the accumulator and the loading rolls 38, 39, 40 are driven so that the loop chambers contain hanging loops of strip. The loading end of the strip is taken into the production machine (e.g. a tube mill) and production is commenced. In steady state operation, strip is fed in at the entry end and out at the exit end at a high speed, e.g. 300 feet per minute (91 metres per minute). When a supply coil is almost used up, the tail end of the used coil and the leading end of a fresh coil are clamped at the clamp and weld station 28 and the leading end of the fresh coil is welded to the tail end of the previous coil in known manner. While this is being done, the production machine continues to run, using the strip in the accumulator.Once the leading end of the fresh coil is fed through the accumulator, the feed speed is slightly increased by accelerating the loading roll 38, so filling the loop chambers 12, 14 and 16. Overfilling of these chambers is prevented by the loop sensors LS12, LS14 and LS16.

It will be realised that variations can be made without departing from the invention. For example, the rollers 18, 19, 20 and 22 could be selectively driven and the loading rolls could be dispensed with. Although it is strongly preferred that the looping rolls should be freely rotatable, a fixed curved strip guide element could be substituted for one or more of the looping rolls in some instances.

In some applications it is desirable to have a pair of supply coils mounted side by side on a laterally movable support, so that a new coil can be quickly brought into alignment with the clamp and weld station.

CLAIMS (filed on 1/9/83) 1. A strip or wire accumulator including a plurality of rotatable rollers spaced from one another and with parallel axes of rotation, a loop-forming strip or wire guide element between and slightly below each adjacent pair of rollers, and a loop chamber extending substantially vertically downwardly beneath each guide element, the arrangement being such that strip or wire in the accumulator hangs freely in loops, one loop being in each loop chamber.

2. A strip or wire accumulator including a plurality of rotatable rollers arranged horizontally spaced from one another, (e.g. at substantially the same horizontal level) and with their axes parallel, the plurality including an entry roller and an exit roller, a looping roll between each pair of adjacent rollers, and a loading roll arranged in association with each roller except the exit roller, each of the loading rolls being arranged to define with its respective roller a nip through which the strip or wire passes, each loading roller being selectively drivable and each looping roller being located above a space (herein called a loop chamber) into which a loop of the strip or wire can fall, in use, under gravity.

3. An accumulator according to claim 2 in which each loading roll is driven via a clutch, and the clutch is controlled in response to a sensor located in a lower region of each loop chamber and below the looping roll which is immediately upstream of the respective loading roll, the sensor being arranged to give a signal upon the presence or proximity of strip or wire, the signal serving to initiate driving of the said loading roll.

4. An accumulator according to claim 1, 2 or 3 in which a stop switch is located in an upper region of the upstream (or entry end) loop chamber, the switch being positioned to be activated when the loop of strip or wire in the first (upstream) chamber is approaching its minimum possible hanging length.

5. An accumulator according to claim 4 in which the switch is arranged to stop a strip-using production process located downstream of the accumulator.

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

Claims

**WARNING** start of CLMS field may overlap end of DESC **. with exit roller 22, and a guide roller 44 guides the strip 26 to a machine (e.g. a tube mill or a stamping machine) where the strip is to be used. A looping roll is located in an upper region of each loop chamber 12, 14, 16. These looping rolls are shown at 52, 54 and 56 respectively. They serve an important function in the present invention, as they cause the strip path between adjacent rollers (e.g. between 18 and 19) to loop downwardly. Consequently the strip automatically and necessarily falls under gravity into the loop chamber (as illustrated) when the linear rate of infeed of the strip at the nip between rollers 18 and 38 exceeds the linear rate of off-take from chamber 12 at the nip between rolls 19 and 39. Without the looping rolls 52, 54 and 56 the strip 26 would pass directly from one nip to the next and the loops in the chambers 12, 14 etc., would not be formed. Each loop chamber has, in its bottom region, a sensor LS which is such as to emit a signal (e.g. an electrical signal) in response to presence or proximity of the strip 26. This signal shows that the relevant loop chamber is full, and that no more strip should be fed thereinto. A signal of this kind from the loop sensor LS 12, LS 14 or LS 16 as the case may be is arranged to actuate the clutch associated with the respective loading roll 39, the loading roll 40 or the tension roll 42, causing the relevant loading or tension roll to be driven so that strip is taken out of the relevant loop chamber. The entry loop chamber 12 has a stop switch SW therein, located in an upper region thereof. The switch SW is sensitive to, and emits a signal in response to, presence or proximity of the strip 26.This signal is used to stop the operation of a downstream stripusing production process, since it indicates that the store of strip in the accumulator is nearly exhausted. It will be realised that the switch SW is arranged to be triggered only in response to presence or proximity of the curved portion 26b of the loop of strip 26, and not in response to presence or proximity of the substantially vertical runs 26a and 26c. Though the switch SW is illustrated as supported by a sidewall 12a of the loop chamber 12, in practice it will be found more convenient to support it by a bracket extending into the chamber from an end wall of the chamber. In operation, the strip is threaded through the accumulator and the loading rolls 38, 39, 40 are driven so that the loop chambers contain hanging loops of strip. The loading end of the strip is taken into the production machine (e.g. a tube mill) and production is commenced. In steady state operation, strip is fed in at the entry end and out at the exit end at a high speed, e.g. 300 feet per minute (91 metres per minute). When a supply coil is almost used up, the tail end of the used coil and the leading end of a fresh coil are clamped at the clamp and weld station 28 and the leading end of the fresh coil is welded to the tail end of the previous coil in known manner. While this is being done, the production machine continues to run, using the strip in the accumulator.Once the leading end of the fresh coil is fed through the accumulator, the feed speed is slightly increased by accelerating the loading roll 38, so filling the loop chambers 12, 14 and 16. Overfilling of these chambers is prevented by the loop sensors LS12, LS14 and LS16. It will be realised that variations can be made without departing from the invention. For example, the rollers 18, 19, 20 and 22 could be selectively driven and the loading rolls could be dispensed with. Although it is strongly preferred that the looping rolls should be freely rotatable, a fixed curved strip guide element could be substituted for one or more of the looping rolls in some instances. In some applications it is desirable to have a pair of supply coils mounted side by side on a laterally movable support, so that a new coil can be quickly brought into alignment with the clamp and weld station. CLAIMS (filed on 1/9/83)

1. A strip or wire accumulator including a plurality of rotatable rollers spaced from one another and with parallel axes of rotation, a loop-forming strip or wire guide element between and slightly below each adjacent pair of rollers, and a loop chamber extending substantially vertically downwardly beneath each guide element, the arrangement being such that strip or wire in the accumulator hangs freely in loops, one loop being in each loop chamber.

6. An accumulator according to claim 1 in

which the loop-forming guide element is formed by a freely-rotatable roller herein called a looping roll located in an upper region of each loop chamber.

7. A strip or wire accumulator substantially as herein particularly described with reference to and as illustrated in the accompanying drawing.