Device for mounting and balancing the rotary knives of a cutter machine

The massive central portion of the knife is formed with an opening of substantially rectangular shape for inserting a boss of square shape integral with a support-washer in turn formed with an opening the shape of which is identical to that of the machine shaft. The boss has an eccentric hole for cooperating with a finger of a stabilizer holding washer provided with a sleeve on which comes the balancing washer of circular shape but having in its center a recess of oblong shape.

BACKGROUND OF THE INVENTION 
The present invention relates to a mounting and balancing device for 
setting and locking in position knives used in machines for cutting, 
crushing and chopping food products, particulaly in pork-butchery and for 
salted products, these machines comprising a number of knives arranged on 
an axis rotating at high speed in a tank of generally semi-toric shape. 
The knives are in a spaced-apart relationship at angles of 180.degree., or 
120.degree., or 90.degree., or 60.degree., or 30.degree., according to the 
number of knives, along one single line. 
As is known, the rotary speed of the knives in modern-machines, so-called 
cutter machines, is extremely high since there exists machines rotating 
normally at 3,000 to 6,000 r.p.m. Such speeds have brought about phenomena 
which hitherto were negligible but are now the source of serious hazards. 
Actually, the centrifugal force generated by the rotation of the knives 
reaches very high values tending to displace them relative to the shaft on 
which they are mounted and, in spite of the precautionary measures taken, 
some of the knives are displaced, with all the disastrous consequences 
involved that can be imagined since said knives come in contact with the 
machine tank, break, deeply score said tank and are in danger to be 
transformed into projectiles extremely dangerous for the surrounding 
personnel. On the other hand, the metallic splinters make the products 
being treated unusable and the price of such unusable products is high 
since several hundreds of kilogrammes are often treated in one single 
working pass. 
One should also note that the very high rotation speed generates vibrations 
if the knives are not carefully balanced. Actually, the weights of new 
knives are little different, but substantial deviations inevitably appear 
after a few sharpenings, which can reach differences of a several tens of 
grammes. Vibrations which are thus caused bring about a general fatigue of 
the machine, the deterioration of the bearings of the knife holding shaft 
and a deafening noise in the work-shop with as consequence painful 
conditions for the operators. 
Attempts have already been made to remedy such disadvantages with various 
mechanical solutions regarding the suppression of the displacement of the 
knives under the effect of the centrifugal force as well as the vibrations 
due to the lack of balance by using complementary re-balancing devices. 
However, the existing devices exhibit usually, together or separately, 
various disadvantages or limitations to their use, such as a high price, 
reduced setting possibilities, limited balancing possibilities, 
restrictions as to the choice of the number of knives used and the way to 
arrange them on the knife holding shaft, etc. 
The present invention remedies such drawbacks by providing a balancing and 
clamping device ensuring complete safety. 
SUMMARY OF THE INVENTION 
According to the invention, in the massive central portion of the knife is 
formed an opening of substantially rectangular shape for the positioning 
of a square-shaped boss rigidly integral with a support-washer, said 
support-washer being formed with an opening the shape of which corresponds 
to that of the machine shaft, the boss having an eccentric hole for 
cooperating with a finger, a stabilizer holding washer provided with a 
sleeve on which comes to rest the balancing washer of circular shape but 
formed in its center with an opening of oblong shape, thereby providing 
the possibility of eliminating the wants of balance for balancing for the 
knives mounted on the machine shaft. 
According to another feature of the invention, there is placed between the 
boss of the support-washer and one of the sides of the knives opening a 
wedge or insert appropriately adjusted, said insert being then locked by a 
locking element or bolt while the boss of the support-washer is also 
locked by a locking element or bolt. 
Various other features of the invention will besides become more apparent 
from the following detailed description.

DESCRIPTION OF A PREFERRED EMBODIMENT 
In FIG. 1 is shown a knife, so-called cutter-knife 1, of a conventional 
shape, the sharp edge of the knife being designated at 2. The massive 
central portion 1d of the knives comprises an opening 3 of substantially 
rectangular shape, but the side 3b of which is not parallel to the 
opposite side 3a but, on the contrary, diverges from right to left 
relative to side 3b. Semicircular cut-outs 4, 5 are provided in the median 
zone of the sides 3b, 3c of the opening 3. 
In FIG. 2 is shown a cylindrical support-washer 10 the central portion 10a 
of which comprises an over-thickness or boss 11 formed with a six-sided 
opening 12 corresponding to the section of the machine driving shaft. 
Moreover, the boss 11 is formed with an opening 13 the purpose of which 
will be explained hereafter. An opening of any other shape could be used 
instead of the six-sided hole 12. 
In FIG. 4 is shown a stabilizer holding circular washer 15 the central 
portion 15a of which forms a sleeve 16. A stud 17 protrudes from the face 
of washer 15 which is opposite the sleeve 16, this stud 17 being provided 
for engaging into hole 13 of the support-washer 10. 
In FIG. 6 is shown a balancing washer 20 of circular shape, but the central 
portion of which being formed at 21 with an oblong-shaped opening and on 
its lower portion 22 with holes 23 of various diameters for reducing its 
weight. Moreover, two tapped studs 25, 26 are provided in diametrally 
opposite positions. As can be seen in FIG. 9, there is also provided a 
cover 30 having a section shape similar to that of a cup or basin (see 
FIG. 10) the central portion of which is formed with a hole 32 for 
positioning the cover 30 on the machine shaft. 
In FIG. 11 is shown a fixed needle 40 supporting a cylindrical 
frustoconical element 41 having at its base a flange 42. The cylindrical 
frustoconical element 41 is provided for the mounting, setting and 
balancing of the knives which are then mounted on shaft 50 (FIG. 12) of a 
cutter machine. In fact, the cylindrical frustoconical element 41 which is 
in unstable equilibrium on the pointed end of needle 40 allows the 
accurate setting of the balance of the knives. Since the threaded cap 45 
can be screwed inside the channel 46, it can be displaced in height 
according to the setting required and thereby adjust the sensitivity of 
the cylindrical frustoconical element 41. The outer diameter of element 41 
corresponds to the diameter of the machine shaft 50. 
As shown in FIG. 8, the central boss 11 of a support-washer 10 is placed in 
the opening 3 of the knife 1 so as to allow placing a knife 1 on the 
cylindrical frustoconical element 41 the face 41a of which comprises six 
sides as the machine shaft 50. Once the first knife 1 is in position with 
its support-washer 10, the second knife 1 is placed with its 
support-washer, off-set by 60.degree. for example relative to the first 
knife, then the third knife 1 off-set by 60.degree. relative to the second 
knife, etc., up to the sixth knife 1 (see FIG. 8 and FIG. 12). In the 
present case, the six knives are angularly spaced apart by 60.degree. on 
the portion 41a of the cylindrical frustoconical element 41. Each knife 1 
is clamped by an intermediate element or insert 60 relative to the 
corresponding washer 10. Insert 60 has a substantially rectangular shape 
and is adjusted so as to fill the space between the boss 11 and side 3b of 
the opening 3, then locking elements 61 are placed in the cut-outs 4, 5, 
these locking elements being small cams which can be turned with a 
screw-driver since they have a slotted head as is shown in FIG. 8. Thereby 
is obtained an accurate fitting of the knife without running the risk to 
see it move later on the machine shaft 50 since the locking elements 61 
which cooperate with the inserts 60 provide a perfect fixation of this 
knife on the shaft 50. As for the six-sided openings 12 of the supporting 
washers 10, the openings of sleeves 13 of the stabilizer holding washers, 
the oblong-shaped hollowed opening 21 of the balancing washer and the 
opening 32 of the cover 30 have a size sufficient for the passage of the 
shaft 50, and the elements can be stacked on each other, it being 
understood that the six-sided shape could be re-modified if the shaft 50 
had another shape, for example a circular shape with a locking device. 
Once the positioning of the knives and their adjustment in length on the 
cylindrical frustoconical element 41 is completed, one proceeds then to 
balancing the assembly by rotating slowly said assembly which is locked by 
introducing into the hole 13 of the support-washer 10 of the last knife 
placed on the shaft of the stud 17 of the stabilizer holding washer 15. 
The balancing washer 20 is then positioned on the sleeve 16 in its neutral 
position and, if the assembly of knives 1 appears as not balanced, the 
balancing washer 20 is placed appropriately so as to compensate the 
movement of unbalance. At this moment and with the assistance of screws 
25, 26, the balancing washer 20 is locked. What is left to do is to 
position the cover 30 so that the assembly be particularly well balanced 
and set as regards its disposition and length. From that moment, the knife 
assembly can be mounted on the shaft 50 of a machine while eliminating all 
the risks generated by the centrifugal force which has a tendency to 
displace the knives 1 longitudinally as well as by suppressing any want of 
balance causing dangerous vibrations to the machine and knives. 
Generally, the fixation of the knives assembly on shaft 50 is carried out 
with the assistance of a locking screw which is screwed on the threaded 
portion 50a of the shaft 50, but other means could also be used. 
As appears clearly in FIG. 2, the support-washer 10 which is formed with a 
square-shaped boss 11 and with a six-sided opening 12 in its center allows 
using in a simple manner said support-washer for positioning the knives in 
a spaced-apart relationship of 30.degree., or 60.degree., or 90.degree., 
or 120.degree., or 180.degree., etc. without any other structure 
modification of the assembly since the combination of a square boss 11 
with the six-sided opening provides this positioning in a simple and easy 
manner. Similarly, the boss 11 provides an excellent guiding means for 
each knife, the contact surface between the sides of the opening 3 and the 
boss 11 being more important than that existing presently between the 
elements for mounting a knife on a six-sided shaft of an existing machine. 
Thereby is provided a better contact via a larger surface, the fatigue of 
the shaft 50 is therefore considerably reduced and there is less wear of 
this shaft and of the ball-bearings maintaining the shaft. 
Attention should also be drawn on the fact that the balancing washer 20 is 
made integrally in one piece, which was not the case with the devices 
comprising a balancing element since one was led to set the balance with 
several separate fly-weights, hence on the one hand more trials and 
errors, and on the other hand a limitation of the out-of-balance 
compensations to a small value hardly in excess of 20 to 30 grammes. 
Finally, one should point out that the wedge or insert 60 which is 
generally made of mild steel easily ground or filed allows an accurate and 
very quick adjustment even under difficult working conditions. 
As is shown in FIGS. 13 and 14a-d, one can also replace wedge 60 by two 
elements 160, 161 having opposite toothings 160a, 161a placed in register 
with each other and between the central boss 11, the support-washer 10 and 
the bottom of the opening 3. Thus by having elements 161, 161d, 161e of 
different heights, one can easily block the support-washer 10 whatever the 
position one wishes to obtain for said washer 10. 
There is therefore no necessity, as with the element 60, to carry out a 
removal of material for setting the knife 1 when worn out, as is the case 
for example after having re-sharpened it.