TECHNICAI. FIELD

This invention relates to a method and apparatus for cleaning waste from the area below machinery. While generally applicable, the invention may find particular use in cleaning waste including fly, trash and yarn fragments settling on an area beneath textile machinery, for example a carding machine, fly frame, spinning frame, loom or other piece of textile processing equipment.

BACKGROUND ART

In the textile industry cleaning from beneath machinery has conventionally been effected by using an air nozzle to blow out the waste from below the machine to where it can readily be swept up for disposal. Such a method has obvious disadvantages, and many pieces of textile processing machinery are now built to incorporate a closed space below the machinery from which air. is sucked to remove waste to an exit duct from where it may be conveyed to a filter which removes the waste for disposal. The space under the machines can be relatively large and a powerful suction unit thus has to be used to achieve reasonable cleaning. Even with such units

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cleaning is by no means ideal.- It has been proposed in U.S. Patent No. 4,081,888 to provide an air channel below machinery in a location such that waste can settle into the air channel. Shutter means are provided which may be switched between an open position permitting entry of waste into the air channel and a closed position where communication from below the machinery to the interior of the air channel is prevented. In the latter position a restricted enclosure is thus provided and waste may be pneumatically removed therefrom in a more efficient manner than would be possible were an attempt made to suck waste from the whole of the area below the machinery. The provision of shutter means as aforesaid, which require mechanical operation, adds to the complexity of the machinery and the shutters are susceptible to jamming.

DISCLOSURE OF INVENTION

According to the present invention a method of cleaning waste from below machinery comprises allowing the waste to fall on to one or more receiving members substantially covering the area below the machinery, vibrating at least one of the receiving members independently of the machinery in a manner such that there is a component of movement perpendicular to the surface of the receiving member and such that the frequency of vibration varies with time over a given range, and creating an air flow ^• below the machinery to remove waste from above the receiving member.

From a further aspect apparatus according to the invention, for removing waste from below machinery, comprises one or more receiving members substantially covering the area beneath the machinery, and one or more variable frequency vibrators mounted so as to

cause vibration of at least one of the receiving members independently of the machinery and with a component of movement perpendicular to the surface of the receiving member, and means for creating an air flow below the machinery across the surface of the receiving member or members.

By vibrating at least one receiving member so that it has a component of motion perpendicular to the surface thereof the waste material is caused to undergo motion with a vertical component which throws it clear from the surface of the receiving member and into suspension in the air in the space beneath the machinery. By causing air to be evacuated from that space the waste is efficiently carried from below the machinery without allowing substantial build up of waste on the receiving member. Different types of waste material have different weights and vibration characteristics and in order to ensure that all waste is at some time suspended in the air above the receiving member this is vibrated over a ranσe of frequencies (preferably a range of at least 30 c.p.s.) which vary with time. The frequency variations preferably occur in a cyclic manner and the range is chosen so that all expected forms of waste will be lifted from the surface of the member or members at some stage of the cycle. Variation of the frequency of vibration also has the effect of preventing constant nodes on the surface where vibration will not occur. The vibration may be effected either continuously or intermittently ^' while the ^' machinery is operating, and in particular the vibrations may be stopped for a period between each cycle of frequency variations.

The necessary air current underneath the

machinery may be effected by blowing compressed air through the space below the machinery to entrain and remove the waste thrown from the surface of the ^• receiving member, or by applying vacuum to a duct opening into the space so that the airborne waste is sucked from the space. Obviously a combination of both techniques could also be used. Desirably the air current is caused to flow at a minimum speed of 15 metres/second. Any commercially available vibrator having the required power and frequency range may be used in the practice of the invention. If the receiving member is in the form of a single plate then it is possible to mount more than one vibrator so that each will cause movement of the plate. If the receiving member is in the form of a plurality of adjacent plates then each plate may have its own individual vibrator, or indeed may have more than one individual vibrator. Plates at certain locations where waste does not accumulate badly may not need to be fitted with vibrators.

Particularly suitable types of vibrator are pneumatic vibrators (for example a Bullows VI vibrator) , or a variable speed motor with an out of balance weight; where the receiving member is in plate form the pneumatic vibrator or the motor may be mounted directly on the plate. Other types of mechanical vibrator may be used as may electrical or ultrasonic vibrators. BRIEF DESCRIPTION OF DRAWING

The sole figure of the accompanying drawing is a schematic representation of a carding engine fitted with apparatus for removing waste, according

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to the invention.

BEST MODE OF CARRYING OUT THE INVENTION

Referring to the drawing, this shows in broad outline a carding engine having, a feed arrangement 1, takerin 2, main cylinder 3 co-operating with flats 4 and doffer 5. The elements of the carding machine are mounted in a frame 6. Mounted belowthe machine within the frame is a plate 7 of thin sheet steel, supported so that it is free to vibrate. For example, the plate may be mounted on base supports 8 of, or ^• incorporating, flexible material such as rubber, or incorporating springs. Alternatively it will usually suffice for the plate to be secured directly to the frame of the carding engine. The plate 7 may be made of an electrically conductive material which can be connected to earth to prevent the accumulation of static charge which would tend to attract waste material. Mounted on the plate is a conventional pneumatic vibrator 9, for example a vibrator as sold under the designation Bullows VI. A compressed air inlet 10 is provided at the delivery end of the carding engine, and a suction outlet 11 is provided at the feed end of the carding engine and connected by a duct to means for filtering suspended waste from the air flow.

When the carding engine is running the vibrator 9 may be driven to cause the plate 7 to vibrate with a component of motion perpendicular to the plate surface. This vibration causes waste material to be thrown from the plate surface where it is entrained in the air current and removed from the space beneath the carding engine.

In order to ensure that all types of waste are

removed the frequency of the vibrator is cyclically varied so varying the frequency of vibration of the plate. The frequency range necessary for any particular environment may readily be determined empirically. In a particular example utilising a Bullows VI vibrator the vibrator was started at a frequency of 3.33 c.p.s. and the frequency was gradually increased at a substantially linear rate up to 83.33 c.p.s. over a period of 4 seconds, after which vibration was stopped. After an interval of 3 minutes the vibration sequence was repeated and this cycle was continued during operation of the carding engine. Application of compressed air and suction were continued throughout the period of operation of the carding engine. When the carding engine was stopped there were minimal residues of waste retained on the plate 7. The actual arrangement of the plate mountings, the position of the.vibrator on the plate, the question of whether more than one vibrator is necessary, and the number and disposition of compressed air inlets and vacuum outlets' may all be varied and designed to give the optimum results with any selected piece of equipment.

The specific embodiment described shows a single horizontal plate as the receiving member. Clearly this could be replaced by a plurality of separate adjacent plates, at least one of which has its individual motor or motors, or by a plurality of linked adjacent plates with a suitable motor arrangement. Any such plate arrangement may be inclined to the horizontal to encourage movement of waste towards the suction outlet or outlets. Indeed the plate or one or more of the plates may have contoured surfaces to encourage movement of waste

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towards any desired region below the machinery.

INDUSTRIAL APPLICABILITY

The invention is applicable to the cleaning of waste from beneath all types of machinery. It may find particular utility in the field of textile processing.