Vortex nozzle for segmenting and transporting metal chips from turning operations

Apparatus for collecting, segmenting and conveying metal chips from machining operations utilizes a compressed gas driven vortex nozzle for receiving the chip and twisting it to cause the chip to segment through the application of torsional forces to the chip. The vortex nozzle is open ended and generally tubular in shape with a converging inlet end, a constant diameter throat section and a diverging exhaust end. Compressed gas is discharged through angled vortex ports in the nozzle throat section to create vortex flow in the nozzle and through an annular inlet at the entrance to the converging inlet end to create suction at the nozzle inlet and cause ambient air to enter the nozzle. The vortex flow in the nozzle causes the metal chip to segment and the segments thus formed to pass out of the discharge end of the nozzle where they are collected, cleaned and compacted as needed.

BACKGROUND OF THE INVENTION 
According to a commonly used method or process for metal removal by means 
of a lathe, a single pointed cutting tool is mounted within a tool holder 
and guided by mechanical slides to interface with a workpiece which has 
been mounted within a fixture and rotated against the cutting tool. This 
process, which is commonly referred to as turning, normally results in the 
removal of an elongated ribbon of metal originating at the cutting tool 
tip which will be referred to herein as a "chip". A long and stringy chip 
is most likely to be formed during the turning of soft or ductile 
materials. 
Theoretically during a single machining "pass" a chip is produced whose 
volume equals the surface area of the workpiece times the depth of cut of 
the cutting tool. Since only a small portion of the total surface of the 
workpiece is removed in a single revolution, overall chip lengths can 
become very long and often exceed many feet in length. Often, the chip 
forms into a ball or curls around the cutting tool or tool post and can 
damage the workpiece surface if not removed manually or through the use of 
a mechanical or hydraulic chip breaker. Mechanical chip breakers are used 
for some materials and usually take the form of an obstacle formed into or 
mounted onto the tool, posing an obstruction to the chip flow, breaking 
the chip into smaller sections. Mechanical obstacles are normally simple 
in design and tend to produce non-uniform chip segments. Hydraulic chip 
breaking is also used for some materials, whereby a high pressure stream 
of coolant is directed straight to the cutting zone breaking the chip into 
very small segments. The use of hydraulic streams requires recovery of the 
hydraulic fluid for recycle to minimize costs and to meet environmental 
concerns. Soft or ductile chips are not easily broken and operator action 
is frequently required. Chip removal is normally accomplished with these 
materials by pulling the chip away from the cutting zone as it is 
generated using tweezers or a hook to engage the chip. 
SUMMARY OF THE INVENTION 
It is a general object of the invention to provide apparatus for 
collecting, segmenting, and conveying metal chips from turning operations. 
A more particular object of the invention is to provide apparatus for 
segmenting metal chips from turning operations without the use of 
hydraulic fluid and wherein the chips are segmented in uniform segments. 
These and other objects are met in accordance with the present invention 
through the use of a compressed gas driven vortex nozzle for receiving the 
metal chips and twisting it to cause the chip to segment through the 
application of torsional forces to the chip. The vortex nozzle of the 
present invention is tubular in shape with a discharge end and an inlet 
end for receiving ambient air which assists in transfer of the metal chip 
from a lathe cutting tool to the nozzle. The angular discharge of 
compressed gas within the nozzle creates a vortex effect which influences 
ambient air entering the nozzle and compressed gas discharging through an 
annular inlet at the intake end of the nozzle, thereby causing the ambient 
air and compressed air discharged through the annular inlet to enter into 
a vortex flow mode. This vortex flow causes the metal chip to segment and 
the segments thus formed to pass out of the discharge end of the nozzle 
where they are collected, cleaned and compacted as needed.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT 
Referring now to FIG. 1, a vortex nozzle 10 is shown in cross section with 
an annular inner assembly 12 threadably engaging annular outer assembly 14 
in a coaxial relationship. O-ring 16 is provided in annular groove 18 to 
seal inner and outer assemblies 12 and 14 to each other and to thereby 
prevent loss of compressed air from annular chamber 19 through threads 20 
and 22. Compressed gas is injected into chamber 18 through pipe means 24 
in communication with a source of pressurized gas (not shown) for powering 
nozzle 10 as will be explained below. 
Adjustment holes 26 are provided at the end of inner assembly 12 for 
receiving a retaining ring tool which can be used to turn the inner 
assembly 12 relative to outer assembly 14, thereby moving the inner 
assembly axially into or out of the outer assembly by virtue of the pitch 
of threads 20 and 22. This allows for precise adjustment of the width of 
annular opening 28 which results in a corresponding change in the 
discharge of compressed air from chamber 18 therethrough as illustrated by 
flow arrows in FIG. 1. Increased flows through opening 28 provide 
corresponding increases in the suction force and total gas consumption of 
the vortex nozzle. As shown, an angled collar or flange 29 formed in outer 
assembly 14 directs the air discharging through passageway 28 inwardly 
into the tapered inlet end 30 of inner assembly 12, thereby initiating 
flow through the nozzle and the creation of a vacuum at the nozzle inlet 
31. According to a preferred embodiment of the invention, flange 29 was 
angled at an angle .theta. of 65 degrees relative to the cylindrical wall 
of assembly 14. The suction force or reduction of pressure at the nozzle 
inlet 31 causes ambient air to enter the nozzle and mix with the 
compressed air discharged into the nozzle through passageway 28 and vortex 
holes 32 described below. 
Turning now to the inner assembly 12 of the vortex nozzle, it is seen that 
a venturi shape is defined by a tapered inlet 30, an untapered cylindrical 
throat section 34 and a tapered discharge portion 36. This specific shape 
causes a drop in pressure and an increase in velocity as a fluid or gas 
flows through it. Furthermore, four individual vortex holes 32 (two shown) 
are machined into the inner assembly 12 to provide fluid communication 
with the compressed gas in annular chamber 19. In one preferred embodiment 
of the invention having a 0.5 inch diameter throat section 34, each of the 
vortex holes 32 was fabricated to be angled 30 degrees relative to a plane 
containing the nozzle center line and offset whereby the center line of 
each vortex hole intersects that plane 0.2 inch from the nozzle center 
line. Different numbers of vortex holes, hole arrangements, inclinations 
and offset dimensions can be used without deporting from the spirit and 
scope of the invention, however. Also, in a preferred embodiment, hole 
sizes of 0.04 in. diameter were used and the holes were spaced 90 degree 
apart. Nozzles having vortex holes 32 arranged at the same axial location 
in the nozzle and aimed so as to intersect the nozzle center line at a 
single point and also arranged in a spiral fashion to intersect the nozzle 
center line sequentially were tested but were found to be less effective 
than the preferred embodiment described above in developing suction and 
for segmenting metal chips. 
A vortex nozzle substantially as shown in FIG. 1 having a 0.5 in. throat 
diameter and an inlet section 30 tapered at 27 degrees was tested using 
compressed air in annular chamber 19 maintained at 80 pounds per square 
inch. Initially, inner assembly 12 was advanced within outer assembly 14 
to close off passageway 28, thereby limiting discharge of the compressed 
air to vortex holes 32. Each of the vortex holes discharged a pressurized 
stream of gas at high speed to create a spiral like vortex flow in the 
direction of the nozzle discharge end 36. This vortex motion of the gas 
discharged through vortex holes 32 acts on a metal chip passing through 
the nozzle causing it to twist and break into small sections. 
Although the vortex action created by discharge of compressed gas through 
vortex holes 32 creates suction at the inlet end 31 of the nozzle through 
collision with free gas molecules in the nozzle and the resultant 
acceleration of those molecules toward the discharge end of the nozzle, 
additional vacuum is desirable to enhance collection of the continuous 
chip from the cutting tool to the nozzle. This additional vacuum or 
suction was created by rotating inner assembly 12 relative to outer 
assembly 14, thereby opening passageway 28 so that part of the compressed 
gas in annular chamber 19 could pass into the inlet end 30 of inner 
assembly 12 where it strikes free gas molecules and accelerates them 
through the nozzle. Suction created by flow through passageway 28 is the 
primary force to attract and collect the chip as it comes off of the 
cutting tool. 
Due to the inclination of flange 29 as shown in FIG. 1, the gas flow 
through passageway 28 is directed toward the center of the vortex nozzle 
and towards discharge end 36. All gas discharging through passageway 28 
and entering through inlet 31 flows through the nozzle in a semi axial 
flow until it meets the gas discharging from vortex holes 32 and joins it 
in vortex flow. This flow attracts and transports the chip and guides it 
into the nozzle where chip breaking takes place as a result of torsional 
forces being exerted on the chip by the vortex flow. 
Turning now to FIG. 2, a system for chip handling is schematically shown 
which encompasses chip management from its point of origin at workpiece 40 
through the collection, breaking, and compaction of chip segments. As 
shown, chip 42 is produced through the cutting action of cutting tool 44 
on workpiece 40 and travels through conduit 46 to a vortex nozzle 10 
substantially as described above in reference to FIG. 1. A chip sensor 48 
is located downstream of vortex nozzle 10 for verifying the presence of 
the chip segments or a continuous chip where the desired chip breakage has 
not occurred. Good functioning of the system is verified where an 
alternating signal is received from the sensor as would be expected where 
a stream of chip segments pass the sensor in the discharge stream from 
nozzle 10. On the other hand, a continuous signal indicates that the chip 
is passing through the nozzle without being broken and no signal at all 
indicates that the chip is not being collected and passed through the 
vortex nozzle. 
A second vortex nozzle 10 has been incorporated into the particular 
embodiment shown in FIG. 2 to assist the first vortex nozzle 10 with 
increased suction. Since the chip segments are normally contaminated with 
liquid coolant used in the cutting operation, the second vortex nozzle may 
be used to blow off excess coolant adhering to the chip segments. this is 
performed by mounting the second vortex nozzle close to a chip collection 
container 50 which is fitted with a sieve 52 allowing the liquid to 
separate from the chips, whereby only the chips are retained in the 
collection container. 
In the event that a solvent is required to clean the chip segments, the 
solvent can be injected into the compressed gas supply of the second 
vortex in an atomized form, thereby becoming part of the vortex, blowing 
upon the chips as they pass through the second vortex nozzle and further 
on those chips contained in the chip collection container. Where material 
inventory is important, the collected chips in chip collection container 
50 may be weighed on a suitable scale 54 either before or after a 
compaction step 56 is performed to produced a reduced volume 58 of 
compacted chip segments. 
From the foregoing description, one skilled in the art can easily ascertain 
the essential characteristics of this invention without departing from the 
spirit and scope thereof and can make various changes and modifications to 
adjust it to various usages and conditions. For example, the vortex nozzle 
as taught herein can be used for purposes other than chip collection and 
breakage. The vortex action and vacuum provided thereby can be used for 
various applications where mixing of gases and/or vacuum pumping of 
material is required. It is intended accordingly that this invention be 
limited in scope only by the claims appended hereto.