GB2320729A - Package dyeing:follow-down device - Google Patents

Abstract

A follow-down device for use in a package dyeing machine has a package plate (1a) with a central bore which receives a vertical column (2) of the package dyeing machine. A housing (3) of the device fits snugly round the column (2) and houses a roller (4) of diablo form which can run smoothly up and down the column (2) but contacts the column (2) at two points only. A wedge plate (5) within the housing (3) is inclined downwardly towards the column (2) and the roller (4) lies between the column (2) and the wedge plate (5). The device is capable of downward movement under its own weight but any force exerted upwards on the plate (1) is transferred to the wedge plate (5) by the roller (4) and positively prevents upward movement of the plate (1a).

Description

A FOLLOW-DOWN DEVICE The invention relates to follow-down devices.

Various follow-down devices have been previously proposed which apply a downward force, usually due largely to their own weight, and are capable of moving downwardly in the event of shrinkage or partial collapse of some object to which they apply a downward force.

One example of a follow-down device is a cap on a package of textile yarn in a dyeing machine.

Textile yarn for many end uses is traditionally dyed on perforated tubular cores, and the yarn on its supporting core is referred to as a package. A package can be dyed in a single package dyeing machine in which it is supported on a vertical perforated pipe or a cruciform or tri-lobe spindle. This is arranged so that liquor containing dye or other treatment chemicals can be made to flow upwardly through the spindle and the perforated core. To prevent the liquor from escaping, the spindle may terminate in a piece of threaded rod and the end of the package and the perforated core can be sealed off with a flat plate held in place by a nut. A similar flat plate can also be used at the bottom.

The liquor can now only escape radially from the inside to the outside of the package by penetrating the mass of yarn. Depending upon the density of the package and the volume of liquor made to flow, a pressure will be built up in the inside of the perforated tube, and this may tend to escape at the flat surfaces of the top and bottom plates.

Accordingly the plates may be formed with concentric corrugations to minimise such leakage.

Some yarns tend to form very tight packages which are difficult to penetrate, other yarns tend to form soft, easily penetrated packages which in fact, may be insufficiently strong to support themselves and which may fall away from the top plates, leaving a space through which dye liquor can escape between the bottom of the top plate and the top surface of the wound yarn. It is customary to wind such packages on to some form of tubular spring or collapsible core, and to compress the package to a shorter than standard length, or to wind on to a longer than standard length core and to compress as required.

It is conventional practice for the machine to be arranged to periodically reverse the flow, so that the uptake of dyestuff can be evened out as far as possible throughout the entire mass of yarn. The package may expand slightly when the direction of flow is from inside to out, tending to press the ends of the package against the inside surfaces of the plates.

On outside-in flow on the other hand, if the top plate is integral with the nut it might retain its original distance above the bottom plate. The pressure of flowing dye liquor might compress the package, reducing its length, and liquor could escape between the top plate and the wound yarn and down the central tube, bypassing the mass of yarn.

At the instant of returning the flow to inside out, the space may be sufficient for the liquor again to bypass the yarn, and it may be impossible to generate sufficient pressure within the package to restore it to its original length and seal the top surface against the plate.

The effects of increasing the temperature of the dyebath differ from fibre to fibre, but can seriously exacerbate these problems, which are increased exponentially as more packages are stacked one above the other on tall spindles in production sized machines.

Follow-down locking devices have been proposed so that when the flow is reversed and compresses the yarn it will keep the plate tightly pressed against the top of the package, and hold it there when inside-out flow is restored.

A manual nperated package dyeing machine equipped with follow-down locking devices in the form of caps was recently opened and left running with clean cold water while the leveleas lowered for demonstration purposes, and when it fell below the level of the top of the packages, water sprayed violently outwards from the space between the tops of the packages and the locking plates, and drenched the observers. This condition is not uncommon, but may be unknown to the user, as normal processing requires the packages to be submerged, and it reveals itself only as inconsistent quality.

The main problem has been that the devices have required some upward movement to effect the locking action. In some cases a pawl was required to engage with teeth spaced some small distance apart, in some cases a latch had to be moved so that by the movement a locking force was applied. In such cases the locking force resulted from the upward movement of the device, this upward movement was sufficient to provide an escape route for the dye liquor, and the condition worsened as the generally flimsy devices deteriorated in the rather rough dyehouse environment.

According to the invention there is provided a follow-down device comprising a housing or frame with a bottom plate to lie upon an object liable to shrinkage, the housing or frame being slidably engageable on an upright column, a fixed wedge plate in the housing or frame defining a wedge surface inclined downwardly towards the upright column and a roller to lie against the wedge surface and the upright column, the roller being able to roll down the upright column to follow shrinkage of the object but jamming against the column due to the wedge surface upon any force being applied tending to move the bottom plate upwardly.

Thus upward movement is positively prevented at all times, while unrestricted downward movement can take place. Any tendency toward upward movement increases the locking force without permitting the bottom plate to move. Preferably the locking force can be released by moving a small latch for easy removal such as to permit a package carrier to be up-ended over a bin for unloading.

The device is locked and unlocked by the application or removal of an upward force on the bottom plate, as opposed to an upward movement of the bottom plate in previously proposed equipment.

Preferably the roller is of bobbin form with relatively large diameter ends and a relatively small diameter middle portion, sometimes called diabolo form, such that it can engage both an upright column of cylindrical form and a planar wedge surface of the wedge plate.

The invention is diagrammatically illustrated by way of example in the accompanying drawings, in which: Figure 1 is a plan view of a follow-down device according to the invention; Figure 2 is a fragmentary sectional elevation on line II-II of Figure 1; and Figure 3 is a sectional elevation on line III-III of Figure 1.

Referring to the drawings, a follow-down device for use in a package dyeing machine has a package plate 1 with a raised middle portion la and a central bore ib which slidably receives a vertical column 2 of the package dyeing machine. The column 2 is a plain round bar which comprises an extension of the package spindle.

A body 3 of the device is formed to fit snugly around the column 2 and is welded to the raised portion la of the package plate 1.

Within the housing 3 a roller 4 of diabolo form which can run smoothly up and down the column 2 but contacts the column 2 at two points only in such a manner as to do least surface damage to the column 2. Also within the housing 3 is a wedge plate 5 which is inclined downwardly towards the column 2 and is welded to the side walls of the housing 3. The roller 4 lies between the column 2 and the wedge plate 5. A lever 6 extends transversely of the housing 3, has an external bent portion by which it may be rotated and an internal lug 6a which, by rotating the lever 6 by means of the external portion, can be brought into engagement with the underside of the roller 4 to raise the roller in the housing 3. A cover plate 7 is provided for the housing 3.

In operation the plate 1 lies on a package in the dyeing machine and exerts a downward force due to the weight of the device. Horizontal force is exerted by the weight of the roller 4 acting against the inclined surface of the wedge plate 5, pressing the roller 4 against the column 2. Any force exerted upwards on the plate 1 is transferred to the wedge plate 5 and is amplified many times by the wedge plate 5 to increase the horizontal force pressing the roller 4 against the column 2 positively to prevent upward movement of the bottom plate 1.

Any slight tendency to downward movement by the plate 1 tends to remove the horizontal force biassing the roller 4 against the column 2 allowing the plate 1 to fall while the roller 4, freed of the restraint of the wedge plate 5, rolls down the column 2 until the plate 1 comes to rest.

The release lever 6 can be operated to lift the roller 4 out of contact with the wedge plate 5 and hold it in a released condition out of contact with anything which could damage it or interfere with it operation. The unit can be inherently resistant to rough handling.

Clearly the follow-down device of the invention is not limited to use in package dyeing machines but can be used to apply a downward force to many other objects likely to shrinkage.

Claims (5)

1. A follow-down device comprising a housing or frame with a bottom plate to lie upon an object liable to shrinkage, the housing or frame being slidably engageable on an upright column, a fixed wedge plate in the housing or frame defining a wedge surface inclined downwardly towards the upright column and a roller to lie against the wedge surface and the upright column, the roller being able to roll down the upright column to follow shrinkage of the object but jamming against the column due to the wedge surface upon any force being applied tending to move the bottom plate upwardly.

2. A follow-down device according to claim 1, in which the locking force can be released by operating a latch to raise the roller.

3. A follow-down device according to claim 1 or claim 2, in which the roller is of bobbin form with relatively large diameter ends and a relatively small diameter middle portion and can engage in two places a cylindrical surface of the upright column and also the planar wedge surface.

4. A follow-down device according to any one of claims 1 to 3, provided as a cap for a package in a dyeing machine.

5. A follow-down device substantially as hereinbefore described and illustrated with reference to the accompanying drawing.