GB2238841A - Linear vibratory conveyor - Google Patents

Abstract

A linear vibratory conveyor in which the vibratory drive 4 operates between two relatively large masses 2 and 7 connected to each other by cantilever springs 5 and in which the oscillatory movement between these relatively large masses is correspondingly small thereby permitting use of a small air gap in the electro-magnetic circuit. The small movement is designed to best match the characteristics of an electro-magnetic drive or other drive with similar characteristics, and utilises a much greater proportion of the power supplied to the electro-magnetic or other drive with similar characteristics. The conveyor trough and its carriage 1 is a third but smaller mass connected to one of the larger masses by cantilever springs 3 and this smaller mass receives a correspondingly large oscillatory movement. Typically the mechanisms of the system are driven at or close to their natural frequencies of oscillation. Various arrangements of masses and springs are disclosed. <IMAGE>

Description

LINEAR VIBRATORY CONVEYOR This invention relates to a linear vibratory conveyor.

Linear vibratory conveyors are used to carry all manner of bulk materials.

These are usually conveyed horizontally, but some inclination to the vertical may also be involved.

Some well-established drives exist which include electro-magnetic, effiectro-dynamic, pneumatic, hydraulic and combination arrangements.

This invention, although applicable to any method of drive, has been conceived especially to overcome problems associated with an electro agnetic method.

Figure 1 shows a typical linear vibratory conveyor in current use.

Figure 2 illustrates the principle of operation of the linear vibrator conveyor which embodies the invention.

Referring to Figure 1, a typical conventional system has a mass associated with the conveyor trough and its carriage, called the active mass 1.

Ttis is connected to the base, called the reactive mass 2, by leaf springs or cantilever springs 3. These springs are usually inclined to the vertical as illustrated to give the required conveyor motion.

The typical vibratory drive 4 is usually arranged to produce a vibratory force between the active mass and the reactive mass and if the reactive mass is much larger than the active mass then the oscillation or vibration is largely taken up by the active mass. In this manner the conveyor trough and carriage is subjected to the oscillation or vibration whilst the base vibrates to a much smaller degree, and being mounted on shock absorbers 5, undesirable transmission of the vibrations to the surrounding area is reduced.

The vibrations of the active mass and reactive mass are about a fixed point on the area on which the vibratory conveyor stands. Typically the oscillations used may be near the resonant frequency.

If electro-magnetic drives of the type having an air gap 6, are employed for larger vibratory conveyors, there is a conflict between having sufficient air gap to allow for the required oscillatory displacement and achieving a small enough air gap to obtain the power required for the oscillation.

specific embodiment of the invention will now be described by we of example with reference to Figure 2.

in this system the vibratory drive L; acts between two relatively large passes and 7. These masses may be regarded as active and reactive respectively or vice versa and are connected to each other by the Deaf springs or cantilever springs 5.

me conveyor trouth ant carriage 1, is a third and smaller mass which may be regarded as reactive because it is not driven directly but receives its motion by means of its connection to one of the larger masses 2, through the leaf springs or cantilever springs 3.

B careful design, involving the distribution of the masses, the conveyor trough receives the required motion but the vibratory movement between the larger masses is relatively small. This small movement allows the elctro-magnetic drive to have a similarly small air gap 6.

The small movement may be designed to match best the characteristics of the vibratory drive. Typically the oscillaitons may be at or near to the resonant frequency.

The usefulness of the invention is that it provides a solution to the probleni stated in the second paragraph on page 2. Although a three mass system is not new, its former use has been in a completely different setting and it does not appear to have been used in this particular way to solve this particular problem. That the solution is not obvious is indicated by the time and money spent and thought and manpower used to try to find a satisfactory method of developing sufficient power in a larger version of the conventional system described on page 2.

The additonal usefulness of the invention is that it provides a radical solution to the problem of system oscillatory rotation about its centre of gravity, which particularly affects vibrators employing troughs with a long overhang. The unwanted vibration may be magnified near the end of the trough and this can cause the material at this point to be bounced backwards instead of forwards. Usuallv the two masses involved are correctly aligned as closely as possible but an unacceptable level of the unwanted oscillation can still occur.

In this special version of a three mass system there exists the potentiality of possible rotational forces due to misalignment about the common centre of gravity of masses 1 and 2. There exists also the potentiality of possible rotational forces due to misalignment about the common centre of gravity of masses 2 and 7. The two centres of gravity are close together, hence in design, in addition to considering the best alignment of the masses involved, the potential rotational vibratory forces involving masses 1 and 2 are used to cancel out the effect of the potential rotational vibratory forces involving masses 2 and 7.

The further usefulness of the invention is that it also achieves a more persistent state of resonance.

This is because it can be designed to have a small but significant bandwidth of high response. This maintains the response against variation in the supply frequency and also has the effect that the high response is maintained for longer periods without adjustment.

Some further embodiments of the invention are shown in figures 3, '; and 5 which all employ the same numbering system. The drive operates between two larger masses 2 and 7 which are connected together bv springs 5 and the third mass which consists of the troth and its carriage 1 is connected to one of the larger masses sr strings 3 and the whole system is supported on shock absorbers 8, which may be of the type placed beneath the mass or for less restra1t may be a specially developed suspension type in which t -ass s re flexible suspended. These supports may be applied to te other large mass instead of the one illustrated.

The embodiment of the invention shown in figure 5 is for a more powerful vibrator which employs for the drive 4 a double interacting magnetic system, one magnetic circuit being carried on each of the larger masses 2 and 7, but figure 5 is also used to portray another version of the single electro-magnet tpe, the drive 4 being one magnet acting on an armature.

This vibratory conveyor provides a means of utilising a much greater proportion of the power supplied to the electro-magnetic drive. Referring to drive mechanisms in general, it enables certain drive mechanisms to achieve a better performance.

This vibratory conveyor has a greatly increased output combined with a reduced input power if this is required.

This vibratory conveyor maintains its high response againsvariation in the supply frequency and maintains its response for long periods of time without the need for adjustment.

This vibratory conveyor largely overcomes the effect of rotational forces which remain due to misalignment of the masses or which increase with increase in the dynamic action.

Claims (5)

1. A linear vibratory conveyor which is particularly appropriate for large size vibratory conveyors which are driven by electric magnetic drives incorporating an air gap.

2. A linear vibratory conveyor which makes more efficient use of the power potential of the electro magnetic drive or other drive and obtains a large oscillatory movement in the required direction without requiring an excessive input power or over heated magnets.

3. A linear vibratory conveyor which largely overcomes the effect of rotational forces which remain due to misalignment of the masses or which increase with increase in the dynamic action.

4. A linear vibratory conveyor which maintains its response against variation in the supply frequency and maintains this response for long periods without the need for adjustment.

This is due to the small but significant bandwidth of high response that can be designed into the system.

Amendments to the claims have been filed as follows 1. A linear vibratory conveyor whereby a vibratory drive operates between two relatively large masses inter-connected by spring means, producing a relatively small amplitude of oscillation, and a workpiece (e.g. conveyor carriage) being the third mass is connected to one of the larger mases by further spring means, the smaller mass receiving a relatively large amplitude of oscillation.

2. A linear vibratory conveyor which is particularly appropriate for large size vibratory conveyors which are driven by electric magnetic drives incorporating an air gap, because the magnetic air gap is reduced.

3. A linear vibratory conveyor which makes more efficient use of the power potential of the electro magnetic drive or other drive and obtains a large oscillatory movement in the required direction without requiring an excessive input power or over-heated magnets.

4. A linear vibratory conveyor which largely overcomes the effect of rotational forces which remain due to misalignment of the masses or which increase with increase in the dynamic action.

5. A linear vibratory conveyor which maintains its response against variation in the supply frequency and maintains this response for long periods without the need for adjustment.

This is due to the small but significant bandwidth of high response that can be designed into the system.