[0001] The present invention relates to a process for smooth ing, buffing and finishing
metal parts and pieces, as well as, in particular, the relative apparatus.
[0002] It is known that deburring and finishing operations on metal pieces are effected
by mixing with abrasives in vibrators or in apparatuses wherein the mass formed by
the pieces and abrasives is subjected to the centrifugal force imparted thereto by
means of a rotating element such as a horizontal plate or disk.
[0003] A finishing apparatus exployting the centrifugal force is described for example in
Italian Patent No. 793.300 granted on November 15, 1967 to Roto-Fiiiish Italiana S.r.l.
[0004] Though the finishing apparatuses operating by centrifugal force represent a progress
with respect to the vibrators, nevertheless, they present the drawback, which incidentally
is common also to other apparatus, of requiring rather prolonged idle times, due to
the necessity of having to interrupt the finishing operation itself for allowing the
processed mass to be gradually transferred from the finishing vat to the screener
or separating device having limited dimensions, which provides for the separation
of the processed pieces from the abrasive material.
[0005] The object of the present invention is to overcome the above noted drawback by providing
an apparatus which has, between the processing vat and the separating device, an intermediate
container suitable to accomodate in a lump the whole mass of processed pieces and
abrasive material, thereupon the processing vat, now empty, may be returned immediately
to its working position to accomodate a new charge to be processed. At the same time,
the intermediate container may gradually transfer by gravity its load in the separation
device until completely empty, thereafter it may return to its initial position to
accomodate the successive charge which has, meanwhile, been processed in the finishing
vat.
[0006] The processing times in the finishing vat and emptying times of the intermediate
collecting container are suitably synchronized in such a way that, when processing
vat has completed its operation cycle, the collecting container is in its starting
position already emptied of any prior charge.
[0007] The present invention will now be illustrated in more detail on the basis of the
annexed sole figure schematically representing the apparatus briefly defined hereinabove.
[0008] A container 1 is initially charged with the pieces to be processed and the abrasives
coming from a vibrating conveyor 11, thereupon it is raised along path 2, shown in
the figure by a dash-single-dot line, until it reaches a position above a processing
vat 3 and is tipped thereinto as shown by the dash line 1'. The charge formed by the
pieces to be processed and by abrasive material thus falls by gravity into the process
ing vat 3 where it is wetted and submerged by an aqueous solution of auxiliary chemicals
coming from a tank 8.
[0009] When the solution has reached the necessary volume as measured by a volumetric counter,
the deburring cycle starts. At the end of this cycle, the aqueous solution is discharged
through a suitable valve located on the bottom of vat 3 and the latter is successively
tipped by rotating it around a shaft 4 according to a semi-circular path S, shown
in the drawing by a dash-single-dot line, until it assumes the end position 3' shown
by a dash line. Operating in this way, the mass of processed pieces and abrasive material
is completely discharged by gravity in a collecting container 6.
[0010] The vat 3' is thence brought back to its initial position 3 making it to travel the
path 5 in an opposite direction, while the controlled rate tipping of container 6
containing the abrasives and processed pieces is simulta neously started by means
of a telescopic arm 7. With the progressive raising and tipping of container 6 according
to a path 9, shown in the drawing by a dash-single-dot line, the processed pieces
and abrasives fall progressively in a vibrating separator 10 which provides for the
separation of the deburred pieces, conveyed outside by means of a vibrating conveyer
15, from the abrasives which are made to fall in container 1 to be re-utilized in
a successive finishing cycle.
[0011] When container 6 has reached position 6', shown in the drawing by a dashed line,
at the end of the tipping run, it is completely empty and is brought back to its starting
position by retracting the telescopic arm 7.
[0012] At this point container 6 is ready to receive a new charge of machined pieces and
abrasives coming from the processing vat 3 which will have completed its operation
cycle and be tipped to the position 3', thus giving start to a successive processing
cycle.
[0013] The advantages which are obtainable with an apparatus of the type herein described
with respect to those so far utilized are mainly represented by the elimination of
idle times, since the screening which takes place in separator 10 is effected during
the working time of vat 3, by an improved dosage and separation of the mass of processed
pieces and abrasives, as the operation times and shifting speed of collecting container
6 are accurately adjustable, as well as by the decrease of collisions during the separation
step of the processed pieces, in that the abrasives are separated in a more regular
and uniform way.
[0014] Though the present invention has been described on the basis of an embodiment thereof
which is at present preferred, it is obvious that modifications and/or changes may
be introduced by those skilled in the art without departing from the scope of the
invention.
1. An apparatus for smoothing metal pieces with a processing vat provided with means
apt to impart a swirling rotary motion by centrifugal force to the mass of pieces
to be processed and abrasives, characterized in that said processing vat (3) may be
tipped by 180° by rotation around a shaft (4).
2. Smoothing apparatus according to claim 1, characte rized in that it comprises further
an underlying collecting container (6) apt to be tipped for the discharge of said
processed pieces and said abrasives in a vibrating separator (10).
3. Smoothing apparatus according to claim 2, characte rized in that said vibrating
separator (10) discharges said abrasives separated from said processed pieces in a
container (1) shiftable along a closed path (2) and capable of being tipped over the
charging hole of said processing vat (3).