Multiple-channel vibrating table for feeding loose parts

A multiple-channel vibrating table for feeding loose parts, including a table which is constituted by a plurality of feeder troughs which are arranged mutually side by side, define the channels for conveying loose parts and are vibrated in order to cause the advancement of the parts along the troughs themselves. The vibrating table further comprises at least one return trough arranged to the side of one of the feeder troughs in order to receive the parts which exit laterally from the feeder trough. The return trough can be activated with a vibrating motion which exerts, on the parts present in the return trough, an advancement action in the direction opposite to the advancement action exerted on the parts in the feeder trough.

BACKGROUND OF THE INVENTION 
This invention relates to a multiple-channel vibrating table for feeding 
loose parts in general. 
Vibrating tables for feeding loose parts of any kind or sort are known and 
are substantially constituted by a plurality of troughs arranged side by 
side which are subjected, by means of various kinds of systems, to a 
vibration which has a longitudinal component so as to cause the 
progressive advancement of the parts along the troughs. 
The shape of the troughs and their number vary in each instance according 
to the type of the parts to be fed and according to the requirements of 
production. 
Generally, multiple-channel vibrating tables are used when it is necessary 
to feed the parts to a machine in a counted, aligned, orientated, sorted 
or otherwise controlled 5 manner. In practice, vibrating tables provide a 
controlled feeding of a machine or of a production line according to the 
requirements of production. 
However, the currently commercially available types of multiple-channel 
vibrating table are unable to fully meet the requirements of machines or 
lines which require high precision in part feeding. In fact, with known 
multiple-channel vibrating tables excesses or non-uniformities in the 
supply of the parts to the final part of the vibrating table can occur, 
and these excesses or non-uniformities are very often passed on to the 
line which is fed by the vibrating table, since known vibrating tables, 
although they even out the position and sequence of advancement of the 
parts, are unable to eliminate excess parts in a manner which complies 
with the necessary production rates. 
Indeed, when it is necessary to have a feeding system which can eliminate 
excess parts, other types of feeder or part movement devices are used 
which have a circular or spiral shape and recover the excess parts which 
are not fed to the machine or line arranged downstream by recycling them 
into the inner part of the feeder. 
These types of feeder or movement devices, however, are more bulky and 
complicated than multiple-channel vibrating tables, and very often they 
cannot be adapted easily to the production line to be fed. 
SUMMARY OF THE INVENTION 
The aim of the invention is to provide a multiple-channel vibrating table 
which is able to ensure high precision in feeding loose parts even in the 
presence of non-uniformities in the feeding of said parts to the vibrating 
table. 
Within the scope of this aim, an object of the invention is to provide a 
vibrating table which has excellent precision in feeding even at high work 
rates. 
Another object of the invention is to provide a vibrating table which 
allows automated recovery of the excess parts. 
A further object of the invention is to provide a vibrating table which is 
simple to manufacture and has competitive production costs. 
This aim, these objects and others which will become apparent hereinafter 
are achieved by a multiple-channel vibrating table for feeding loose parts 
in general, which comprises a table constituted by a plurality of feeder 
troughs arranged side by side and defining channels for conveying loose 
parts, motor means being provided in order to vibrate said table, 
characterized in that it comprises at least one return trough arranged to 
the side of one of said feeder troughs in order to receive parts which 
exit laterally from said feeder trough, said return trough being 
activatable with a vibrating motion which exerts, on parts in said return 
trough, an advancement action in the direction opposite to the advancement 
action exerted on parts in said feeder trough.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
With reference to the above figures, the multiple-channel vibrating table 
according to the invention comprises a table, generally designated by the 
reference numeral which is constituted by a plurality of feeder troughs 2 
which are arranged mutually side by side and extend parallel to one 
another. 
In the illustrated embodiment, which is to be considered as non-limitative, 
each feeder trough 2 has a V-shaped transverse cross-section which is 
fixed to the upper side of a vertical plate 2a. 
The feeder troughs 2 can be connected, by virtue of controllably 
activatable connection means 3, to motor means 4 which vibrate the troughs 
2 so as to cause the advancement of the loose parts along the troughs 2 
from an input station 5, constituted for example by a hopper 6, to an 
output station 7 which can be constituted by the inlet of a packaging 
machine or of a production line in general, as will be described in 
greater detail hereinafter. 
According to the invention, laterally to at least one of the feeder troughs 
2 there is a return trough 8, arranged so as to receive the excess parts 
which exit from the feeder trough 2 and is connected to motor means 
activating said return trough 8 with a vibrating motion which makes the 
parts advance in a direction opposite to the advancement direction 
imparted to the parts in the feeder trough 2. 
Preferably, there is a return trough 8 for each feeder trough 2, and the 
feeder troughs 2 are provided with a lateral recess portion 9 on the side 
of the related return trough 8. The size of said recess portion 9 is a 
function of the feeding requirements and of the dimensions of the loose 
parts, so as to unload the excess parts fed in the troughs 2 onto the 
return troughs 8. Furthermore, at said recess portion 9 it is possible to 
provide leveling means, for example a rod 10, which facilitate the passage 
of the excess parts from the feeder trough 2 to the return trough 8 
In practice, the vibrating table is constituted by feeder troughs 2 
alternated with return troughs 8. 
The motor means 4 impart to the feeder troughs 2 and to the return troughs 
8 a vibration with reciprocating motion along a direction which has a 
component which is parallel to the longitudinal extension of the troughs, 
which are mounted respectively on first and second guiding means which 
define, for the troughs, sliding directions which are inclined with 
respect to the vibration direction imparted by the motor means so as to 
obtain the required effect of part advancement. 
Said first and second guiding means are constituted by blocks 11 which are 
applied to the fixed supporting structure 12 of the vibrating table. Each 
block 11 has, on its lateral faces, which are arranged vertically, two 
grooves 13 and 14 which are inclined in opposite directions with respect 
to the vibration direction 15 imparted to the troughs 2 and 8. 
The first groove 13 slidably accommodates a pin 16 which is fixed to the 
vertical plate 2a of the feeder trough, whereas the second groove 14 
slidably accommodates a pin 17 fixed to the return trough 8 by means of a 
bracket-like element 18. 
Conveniently, each block 11 is made of two portions 19a and 19b which 
transversely delimit the two grooves 13 and 14 and are moved close 
together by the action of a spring 20 which acts on the lower face of the 
block. The spring 20 thus keeps the transverse walls of the grooves 13 and 
14 in contact with the related pins 16 and 17, recovering any play which 
might arise due to wear. 
Furthermore, the groove 13 accommodates two pins 16 of two adjacent feeder 
troughs 2, and the space for the sliding of the two pins 16 is delimited 
by an intermediate partition 21. 
In practice, the vibrating table is preferably constituted by a plurality 
of pairs of troughs arranged mutually side by side, Wherein each pair is 
constituted by a feeder trough 2 and by a return trough 8 which are 
mounted on two blocks 11 which are mutually spaced along the longitudinal 
extension of said troughs. The blocks 11 are arranged between these trough 
pairs so as to simultaneously support the feeder troughs 2 of two pairs of 
adjacent troughs. 
Each return trough 8 has a part discharge passage 22 which is arranged 
above a recovery channel 43 by means of which the parts arriving from the 
return trough 8 are collected and/or conveyed back to the hopper 6. 
The motor means 4 comprise a mass 23 which is vibrated with a reciprocating 
motion along the direction 15 by virtue of known means, such as for 
example a mechanical system with an eccentric element, not illustrated for 
the sake of simplicity. The direction 15, which is parallel to the 
longitudinal extension of the troughs 2 and 8, is preferably horizontal. 
The vibrating mass 23 is suspended, by means of flexible arms 24, from the 
fixed supporting structure 12 of the vibrating table, and a longitudinal 
end of the return troughs 8 is fixed to said vibrating mass. 
The feeder troughs 2 can be controllably connected to the vibrating mass 
23, preferably in an individual manner, by virtue of the connection means 
3 which comprise, for each trough 2, a flexible tab 25 which is fixed to a 
longitudinal end of the trough 2 and ends with a shaped sliding block 26 
which can be coupled to a seat 27 which is shaped complementarily and is 
defined in the vibrating mass 23. 
Actuation means act on each tab 25 and can be controllably activated so as 
to engage or disengage the sliding block 26 with or from the seat 27 in 
order to connect or disconnect the related trough 2 to or from the 
vibrating mass 23. 
Said actuation means comprise a fluid-activated cylinder 28 which is 
supported by the fixed supporting structure 12 and acts with its stem 28a 
on a presser element 29 with the interposition of an articulation 30 of a 
known type which does not transmit transverse loads to the stem 28a. 
The presser element 29 is constituted by a cylindrical body 31 which passes 
through another cylindrical body 32 which has a larger diameter and is 
made of low-friction material for the tab 25 which it faces with its lower 
end. The lower end of the cylindrical body 31 passes through a 
longitudinal slot 33 of the tab 25 and ends with an enlarged head 34 which 
is accommodated in a seat 35 defined in the sliding block 26. 
The cylinder 32 can slide vertically in a seat 36 defined in the supporting 
structure 12 and has an upper shoulder 37 for the cylindrical body 32. 
The cylindrical body 31 has a shoulder 38 which is directed downward and 
faces an abutment of the cylindrical body 32. 
In this manner, when the actuation of a feeder trough 2 is required, the 
cylinder 28 is actuated so that it causes the insertion of the shaped 
sliding block 26 in the seat 27 of the vibrating mass 23. In this 
engagement position, the sliding block 26 is pressed in the seat 27 by the 
cylindrical body 32. 
When the actuation of the feeder trough 2 is to be interrupted, the 
cylinder 28 is actuated in the opposite direction, so that the sliding 
block disengages from the seat 27 and the tab 25 is pressed, by virtue of 
the action of the cylindrical body 31, against the lower end of the 
cylindrical body 32, thus locking the related feeder trough 2. 
In practice, the feeder troughs 2 can be actuated independently of one 
another according to the feeding requirements of the machine or production 
line arranged downstream of the vibrating table 1. 
The operation of the vibrating table according to the invention is as 
follows. 
The reciprocating vibration along the direction 15 of the return troughs 8 
and of the feeder troughs 2, which are connected to said vibrating mass 
23, produces a reciprocating movement of the troughs along the grooves 13 
and 14, in which the pin 16 of the feeder trough 2 slides in the groove 13 
while the pin 17 of the return trough 8 slides in the groove 14 and in 
which the two grooves 13 and 14 are inclined in opposite directions with 
respect to the vibration direction 15 (FIG. 8); the effect of this 
movement is the advancement of the parts along the feeder troughs 2 and 
the advancement, in the opposite direction, of the parts which fall into 
the return troughs 8. 
During advancement along the feeder troughs 2, the excess parts in fact 
fall into the return troughs 8 without causing alterations with respect to 
the required amount or arrangement. Furthermore, the parts discharged onto 
the troughs 8 are collected and can be easily fed back into the hopper 6. 
In practice it has been observed that the multiple-channel vibrating table 
according to the invention fully achieves the intended aim, since the 
discharge of the excess parts onto the return troughs ensures high 
precision in feeding at the output of the vibrating table even at high 
operating rates. 
Furthermore, the use of blocks with inclined grooves makes it extremely 
easy and rapid to assemble the vibrating table and also allows to increase 
the number of troughs used in a simple and rapid manner and with modest 
costs. 
The multiple-channel vibrating table thus conceived is susceptible to 
numerous modifications and variations, all of which are within the scope 
of the inventive concept; all the details may furthermore be replaced with 
technically equivalent elements. 
In practice, the materials employed, as well as the dimensions, may be any 
according to the requirements and the state of the art.