Vibratory Feeding

Vibratory Feeding

Vibratory Feeding - The vibratory principle may be applied to troughs, bins, elevators and bowl hoppers. Vibratory feeders are driven by an electromagnet whose coil is fed by an alternating current or by a pulsating direct current obtained through a half-wave rectifier.

The gap between the armature and core of the magnet varies from 0.5 mm to 1.5 mm and. a frequency of 50 Hz is usually employed. In order to move articles by this means, it is necessary that the vibratory motion of the surface on which they rest shall have both horizontal and vertical components. This is achieved by mounting the platform, trough or container on flat springs inclined at an angle.

A diagram of a vibratory hopper is shown in Fig. The shallow container B is provided with a track A, about the width of the components and shaped in the form of a helix round its inner periphery. The baseplate F of the hopper carries the armature C of the magnet, which acts in conjunction with the stationary core energized by the coil D.

The upper, vibrating element of the hopper is supported from the base on a number of flat springs E, equally spaced and inclined at an angle (usually 20-30°) in order to give both vertical and torsional components to the vibration. The base G is mounted on resilient feet H which may be restrained in some way to prevent the apparatus moving about.

Usually the track is sloped slightly towards the inner wall of the hopper so that the parts do not slip off, and the angle f3 of the helix is kept down to about 3° or 4°.

Vibratory Hopper

Vibratory Feeder

In operation, a single component being fed; for example, washers will need a 11at track with means to ensure that they travel singly and not in piles; screws and headed articles may require a slotted track supporting under the head; for unsymmetrical components, means to reject from the track articles wrongly orientated are required, and so on.

In addition, some baffling may be necessary in the region where the track starts, in order to avoid blockage and to disperse the contents of the hopper suitably for entry to the track. Vibratory feeders in the form of hoppers range from 100 mm to 600 mm diameter, and when applied to round disc components may be constructed to handle a range of from 6 mm to 75 mm diameter.

The speeds of movement vary from 1 to 4m/min. For very thin, light components, in order to increase the coefficient of friction to an amount sufficient to ensure satisfactory feeding, it may be necessary to treat the surface of the track with some compound.