GB2166077A - Briquette making machine - Google Patents

Abstract

The invention relates to machines for making compressed fuel briquettes from waste cardboard and similar material, of the type described in GB 2 148 779A in which the guillotine and compressing piston are driven by rack and pinion drives. The improvement over the prior art is that the guillotine is power- driven by a double acting hydraulic ram; another double-acting hydraulic ram advances and retracts the compressing piston; and a common hydraulic circuitry links these rams in such a way that, as the guillotine-lifting ram retracts the guillotine from the breach, the hydraulic fluid which exhausts from that ram is automatically transferred to the ram which drives the waste-compressing piston and moves that piston back from the compressing chamber breach so that the piston retracts substantially simultaneously with the retraction of the guillotine.

Description

SPECIFICATION Briquette making machine Field of the Invention The invention relates to machines for making compressed fuel briquettes from waste cardboard and similar material.

Review of the Prior Art Our UK Patent Application No 83 31123 filed 22nd November 1983 and published with publication No 2148 779A describes and claims a machine to make briquettes from waste, the machine comprising a waste-receiving bin, a plate to sweep waste from the bin towards and at least partly into the initially open breach of compression chamber, powerdriven guillotine means progressively to close off the breach, to shear waste straddling the breach and to compress the waste within the compression chamber, the guillotine means being retractable from the breach, and a power-driven piston movable transversely to the guillotine means to clear the compressed waste from the compression chamber and further compress it against and eventually through a constricted discharge orifice which is so configured as to groove longitudinally the emergent briquette.

Such a machine will be referred to in this present specification as a machine of the kind in question.

In the machine specifically described and illustrated in Publised Application 2148 779A the guillotine is power-driven by a motor operated rack and pinion drive, and the piston is similarly power-driven by another and separately energised rack and pinion drive.

Such a machine is extremely expensive to manufacture. The rack and pinion drives, and the rotating shafts associated with them, involve a great deal of machining. Each individual drive needs its own motor and driving unit. All have to be synchronised with one another. The rack and pinion drives wear very badly because of the high forces to which they are subjected, and they are inherently susceptible to backlash and side play. The complexity of the synchronising circuitry, and the number and relative complexity of the individual drives and motors, means that there is statistically a high chance of breakdown in some part of the machine and a correspondingly low chance of spotting the failed area quickly amongst so many mechanisms.

In addition to these drawbacks, the rack and pinion drives are relatively slow to operate.

Also they do not operate entirely smoothly, because of the inevitable play and frictional interaction between the moving components.

Summary of the Invention According to the present invention, in a machine of the kind in question, the guillotine is power driven by a double-acting hydraulic ram; another double-acting hydraulic ram advances and retracts the compressing piston; and a common hydraulic circuitry links these rams in such a way that, as the guillotinelifting ram retracts the guillotine from the breach, the hydraulic fluid which exhausts from that ram is automatically transferred to the ram which drives the waste-compressing piston and moves that piston back from the compressing chamber breach so that the piston retracts substantially simultaneously with the retraction of the guillotine.

The use of hydraulic rams gives an altogether smoother and more truly incremental action through all the main moving parts of the machine than does the use of rack and pinion drives or equivalent mechanical means.

It also makes it possible for a single motor and twin-pump unit to drive both rams. If the guillotine or the waste-compressing piston jams in its movement, a hydraulic relief valve can blow and prevent damage. With the mechanically driven machine described and illustrated in Published Application 2148 779A, by contrast, damage would be inevitable in such a situation.

Preferably, in a machine of the kind in question, the hydraulic circuitry is such that the guillotine reaches the limit of its retracting movement before the waste-compressing piston has moved fully back from the compression chamber breach, and hydraulic fluid then continues to be fed automatically to the ram retracting the waste-compressing piston and subsequently holds the piston in its fully retracted position as the guillotine is subsequently driven towards the breach.

In all these respects the present invention provides a machine which constitutes a novel and non-obvious advance over the machine described and illustrated in Published Application 2148 779A. Although the specification of Published Application 2148 779A says that the rack and pinion drives to the guillotine and to the compressing piston could both be replaced by fluid driven rams, in no way does it disclose or suggest the specific features which characterise a machine embodying the present invention.

Brief Description of the Drawings The single drawing accompanying this description is a hydraulic circuit diagram for a machine of the kind in question.

Description of the Preferred Embodiment In the drawing, a machine of the kind in question has rams 14 which swing the plate towards and away from the compression chamber of the machine and which are the direct equivalent of the similarly referenced rams 14 shown in the drawings of Published Application 2148 779A. Another ram 27 presses a ridged wheel against the surface of the emergent briquette and is a functional equivalent of the ram similarly referenced 27 in Published Application 2148 779A. With two important exceptions, to be described below, the rest of the machine is essentially equivalent in construction and function to the machine described and illustrated in Published Application 2148 779A and the reader is di rected to the published specification of that prior application for any further details he may need to put the present invention into practice.

The two exceptions are the power driven means which raise and lower the guillotine and which advance and retract the wastecompressing piston. A single large double-act ing hydraulic ram shown in the accompanying drawing is a functional equivalent of the rack and pinion drive 9 of the machine of Published Application 2148 779A. It raises and lowers the guillotine of the machine. A similarly dou ble-acting hydraulic ram replaces the rack and pinion drive 23, 24 of the previous machine to advance and retract the waste-compressing piston (referenced 23 in the previously described and illustrated machine). The hydraulic circuit illustrated operates as follows: Oil is fed under pressure from pumps P1 and P2 via solenoids S and Y to cause ram '9' to retract and hence to raise the guillotine.

As the guillotine rises, the oil automatically exhausted from the upper end of ram '9' is supplied under pressure via solenoid & to cause ram '23, 24' to retract and hence to move the waste-compressing piston back from the compression chamber breach.

As the guillotine rises, and oil automatically exhausts from the top end of ram '9', rams 14 are pressurised via solenoid B to swing the sweep plate towards the compression chamber breach.

At the same time, ram 27 again is pressurised to press grooved roller 26 (not illustrated here) against the surface of the emergent briquette.

The guillotine reaches the top of its upward movement shortly before the simultaneouslyretracting waste-compressing piston reaches the limit of its backward movement. With the piston in that back-limit position, it is held -there under pressure, whilst oil is now supplied via solenoid S into the top of ram '9' to move the guillotine downwards thus progressively closing off the breach of the compression chamber and shearing any waste straddling the breach.

When the guillotine has reached the bottom limit of its downward movement, oil is now supplied under presure via solenoid T to ram '23., 24' and the previously-pressurised oil is allowed to exhaust automatically from the other end of the ram cylinder so that the ram extends to move the waste-compressing piston into and through the compression chamber breach and hence to compress and eject the waste material in briquette form through the discharge orifice of the machine.

Claims (4)

1. A machine of the kind in question, in which the guillotine is power driven by a double-acting hydraulic ram; another double-acting hydraulic ram advances and retracts the compressing piston; and a common hydraulic circuitry links these rams in such a way that, as the guillotine-lifting ram retracts the guillotine from the breach, the hydraulic fluid which exhausts from that ram is automatically transferred to the ram which drives the waste-compressing piston and moves that piston back from the compressing chamber breach so that the piston retracts substantially simultaneously with the retraction of the guillotine.

2. A machine according to Claim 1, in which the hydraulic circuitry is such that the guillotine reaches the limit of its retracting movement before the waste-compressing piston has moved fully back from the compression chamber breach, and hydraulic fluid then continues to be fed automatically to the ram retracting the waste-compressing piston and subsequently holds the piston in its fully retracted position as the guillotine is subsequently driven towards the breach.

3. A machine according to Claims 1 or 2, in which the discharge orifice is at least partially defined by one or more ridged wheels held against the surface of the emergent briquette by power operated means, the power operated means also comprising a hydraulic ram and this ram is pressurised against the briquette by hydraulic fluid which enters the ram under pressure automatically as the hydraulic fluid is exhausting from the ram which is retracting the guillotine from the breach.

4. A machine of the kind in question arranged substantially as described herein, with reference to, and as illustrated in the accompanying drawing.