Machine tools abstract
A self-feeding shredding device, particularly for liquid lubricant/refrigerant
filtration plant for machine tools with swarf removal, incorporating
a channel element in which a motorized screw conveyor sits, having
one end of reduced diameter that passes through an internally grooved
cylindrical body. A lobe rotor is axially faced up against the outside
of the grooved cylindrical body and its rotation controlled by the
screw conveyor. The swarf, unwound and stretched out from the reduced
diameter end tip of the screw conveyor along the grooved cylindrical
body, is pushed towards the lobe rotor and shredded.
Machine tools claims
What is claimed is:
1. A self-feeding shredding device for machine tools with swarf
removal, including a conveyor incorporating a channel for feeding
the lubricant/refrigerant liquids and in which a motorised screw
is positioned, said screw having an end tip which constituting a
drive member for a shredding group incorporating an internally-grooved
cylindrical body arranged coaxially with respect to the said end
tip of said screw and a lobe rotor, axially faced against the outside
of the said grooved cylindrical body and rotationally driven by
the said screw.
2. A shredding device according to claim 1 wherein said end tip
of said screw has a smaller diameter that the rest of the said screw
3. A shredding device according to claim 1 wherein said end tip
of said screw has an end tang that stands proud of the said grooved
cylindrical body and on which the said lobe rotor is coupled in
4. A shredding device according to claim 3 wherein said lobe rotor
is inserted inside a bottom ring frontally fixed to the said grooved
5. A shredding device according to claim 1 wherein said lobe rotor
is equipped with a number of lobes ranging from 2 to n, preferably
from 4 to 6.
6. A shredding device according to any of the previous claims,
wherein said channel element is equipped with bottom openings.
7. A shredding device according claim 1 wherein end said screw
conveyor has an initial end functionally connected to a drive group
equipped with an automatic counter-rotation device.
8. A shredding device according to claim 1 wherein grooves said
cylindrical body has axially-arranged grooves.
9. A shredding device according to claim 1 wherein said cylindrical
body has grooves angled with respect to the axis thereof.
10. A shredding device according to claim 1 wherein said end tip
of said screw is radially floating with respect to the said grooved
Machine tools description
BACKGROUND OF THE INVENTION
 The present invention refers in general to machine tools
with swarf or chip removal.
 Traditionally, in industrial plants that use such machine
tools, the relative lubricant/refrigerant liquids and machining
swarf are transported, generally via inclined floor-level channels,
to filtration plants that separate the solid parts from the liquids
so that the latter can be reutilised.
 This solution involves evident complications due to the
layout of the channels, as well as the space occupied by the channelling
and flexibility problems in relation to the positioning of the machine
SUMMARY OF THE INVENTION
 Hence, it would be auspicious to eliminate these channels
and connect the lubricant/refrigerant liquid discharges from the
machine tools with the filtration plant via a network of overhead
pipes, which is less complicated, less space-consuming and much
more flexible when setting up. Nevertheless, this requirement does
not reconcile with the presence of long metal swarf in the lubricant/refrigerant
liquids. Such swarf is normally of variable length and even several
centimeters long, and therefore cannot be transferred to the filtration
plant connection piping using normal hydraulic pumps.
 The object of this invention is that of solving this problem
and to reduce the swarf length so as to enable the pumping of lubricant/refrigerant
liquids containing swarf using normal hydraulic pumps.
 According to the invention, this objective is achieved by
a self-feeding shredder, characterized by the fact that it consists
of a conveyor including a channel element for feeding the lubricant/refrigerant
liquids in which a motorized screw conveyor sits, the end tip of
which constitutes the advancement member of a shredding group, including
an internally grooved cylindrical body arranged coaxially to the
said end tip of the screw conveyor and a lobe rotor axially faced
against the outside of the said grooved cylindrical body and controlled
in rotation by the said screw conveyor.
 The combined effect of the rotation of the screw and the
presence of the grooves inside the cylindrical body of the shredding
group creates an effective unwinding, straightening and stretching
action on the elongated particles of metal swarf as they are self-fed
to the rotor. The interaction between the lobes of the rotor and
the extremity of the grooved cylindrical body faced against it produces
a grinding and shredding action, reducing the size and length of
the metal swarf particles to levels at which they can be pumped,
together with the lubricant/refrigerant liquids, to the filtration
 The same advantageous functional result is achieved even
in the case the shredding device according to the invention is employed
for the mere disposal of the swarf produced by the machine tools,
i.e. independently of the presence of a lubricant/refrigerant filtration
plant, i.e. independently of the presence of a lubricant/refrigerant
filtration plant, and/or of distribution and/or conveying systems
for the lubricant/refrigerant liquids and swarf (e.g. even in the
case the swarf are removed by means of collecting containers).
 In order to render the unwinding and stretching effect on
the elongated swarf more efficient, the aforesaid end tip of the
screw conveyor has a diameter that is opportunely smaller than that
of the rest of the aforesaid screw. This end tip is equipped with
an opportune end tang that stands proud of the aforesaid cylindrical
body and on which the lobe rotor is engaged for rotation.
 Another characteristic advantage of this invention is that
the motorised group driving the screw conveyor is equipped with
a counter-rotation device, which is set up to automatically intervene
during normal running in cases where rotation of the screw slows
down or stops due to swarf clogging or blockages.
BRIEF DESCRIPTION OF THE DRAWINGS
 The invention will now be described in detail with reference
to the attached drawings, which are supplied purely as a non limitative
 FIG. 1 is a schematic perspective of a self-feeding shredding
device according to the present invention,
 FIG. 2 is a longitudinal, side-section view of FIG. 1
 FIG. 3 is an exploded view of FIG. 1
 FIG. 4 is a larger-scale front view of a first example of
lobe rotor actuation on the shredding device, and
 FIG. 5 is a similar view of a second type of lobe rotor
DETAILED DESCRIPTION OF THE INVENTION
 According to the present invention, the self-feeding shredding
device, as exemplified in the drawings, includes a support frame,
generically indicated as item 1 arranged for mounting in correspondence
with the lubricant/refrigerant liquids outlet of a machine tool
or group of machine tools with swarf removal. The lower part of
the support frame (1) carries a horizontal channel element (2),
the bed of which has a series of slots (3) and in which a motorised
screw conveyor (4) sits.
 In the example shown, the screw conveyor (4) incorporates
a long tubular element (5) with the blade (6) of the screw mounted
on its external surface and coupled at one end to a shaft (7). The
shaft (7) is mounted on the frame (1) using, for example, roller
bearing supports (not shown) to allow rotation and is connected
to a motorised drive group. In the case of the example shown, this
group is comprised of an electric motor and a chain drive indicated
schematically as 9.
 A counter-rotation device is opportunely coupled with the
motorised drive group. This counter-rotation device might incorporate
a sensor for the angular speed of the shaft (7) or an absorption
sensor for supply current to the motor (8), suitable for automatically
controlling--for motives explained in the following--the halting
and rotation of the screw conveyor (4) in the opposite direction
to that of normal running for a predetermined number of revolutions.
 The height of the screw blade (6) is reduced in correspondence
with the end tip (10) of the screw conveyor (4). This tip (10) passes
coaxially through a cylindrical sleeve (11) having on its inner
circumference a series of grooves (17), which may be oriented axially
or with an angle relative to the axis of the sleeve (11), and is
fixed at one end, via a flange (12), to a vertical support plate
(13) that is, in turn, rigidly fixed to the channel element (2).
The other end of the grooved cylindrical sleeve (11) has another
flange (14) onto which a bottom ring (15) is fixed.
 An axial tang (16) coupled in rotation within the end tip
(10) of the screw conveyor (4) has a prismatic tip (18) onto which
a lobe rotor (19) is keyed. This rotor (19), which axially faces
the external end of the grooved cylindrical body (11), can have
from 2 to n lobes: FIGS. 4 and 5 show two examples of alternative
implementations in which the rotor has respectively six and four
lobes, or radial arms. In operation, the lubricant/refrigerant liquid
and small-size swarf are discharged under gravity from the bed of
the channel element (2), via the relative slots (3), to a collection
tank for pumping to the filtration plant.
 Longer particles or accumulations of swarf are transferred
by the screw conveyor (4) in the direction of its end tip (10).
Due to the reduced height of the screw blade (6) and the presence
of the grooved cylindrical body (11), the swarf is subjected to
an unwinding and stretching action in this end tip zone (10), whilst
being simultaneously advanced in the direction of the rotor (19).
Due to the effect produced by the interaction between the edges
of the lobes of the rotor (19) and the end of the cylindrical body
(11) facing them, the swarf is subjected to a grinding and shredding
 Following this grinding and shredding action the swarf,
which leaves the device via the bottom ring (19), reaches the collection
tank where it is pumped with the lubricant/refrigerant liquid to
the filtration plant. In cases where swarf amasses and clogs in
the end tip (10) zone to the extent that it causes the rotation
of the screw conveyor (4) to slow down or even stop, the previously
described counter-rotation device will automatically rotate the
said screw conveyor (4) in the opposite direction for a brief period
of time to restore normal operating conditions. Nevertheless, it
is necessary to underline that the risk of swarf blockage is reduced
by the fact that the end tip (10) of the screw conveyor (4) is not
supported, but is free to float radially with respect to the grooved
cylindrical body (11).
 Naturally, it is understood that the constructional details
and the forms of realization could be extensively changed with respect
to that described and illustrated without leaving the scope of this
invention, as defined in the following claims. Thus, as already
pointed out in the above, the shredding device according to the
invention can also be advantageously employed for the mere disposal
of the swarf produced by the machine tools, i.e. even in the absence
of lubricant/refrigerant filtration plants, i.e. independently of
the presence of a lubricant/refrigerant filtration plant, and/or
of distribution and/or conveying systems for the lubricant/refrigerant
liquids and swarf (e.g. even in the case the swarf are removed by
means of collecting containers).