U.S. patent application number 10/406781 was filed with the patent office on 2003-10-09 for method and apparatus for improving operation of masonry saws and drills.
Invention is credited to DeBlasio, Michael J..
Application Number | 20030188893 10/406781 |
Document ID | / |
Family ID | 25266638 |
Filed Date | 2003-10-09 |
United States Patent
Application |
20030188893 |
Kind Code |
A1 |
DeBlasio, Michael J. |
October 9, 2003 |
Method and apparatus for improving operation of masonry saws and
drills
Abstract
An improved method and apparatus for sawing or drilling concrete
or like material comprises use of a fluid flow device for
transmitting a stream of water from a pressurized water supply to
the cutting elements of a masonry saw or core drill and for
injecting a speed-enhancing compound into the stream of water, with
the compound being injected under the influence of a
venturi-induced suction force created by the stream of water as it
flows through the device. Preferably the device includes means for
varying the rate at which the speed-enhancing compound is sucked
into the water stream.
Inventors: |
DeBlasio, Michael J.;
(Littleton, MA) |
Correspondence
Address: |
Nicholas A. Pandiscio
Pandiscio & Pandiscio, P.C.
470 Totten Pond Road
Waltham
MA
02451-1914
US
|
Family ID: |
25266638 |
Appl. No.: |
10/406781 |
Filed: |
April 3, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10406781 |
Apr 3, 2003 |
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09834314 |
Apr 13, 2001 |
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6561287 |
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Current U.S.
Class: |
175/67 ;
175/424 |
Current CPC
Class: |
B28D 7/00 20130101; B28D
7/02 20130101 |
Class at
Publication: |
175/67 ;
175/424 |
International
Class: |
E21B 007/18 |
Claims
What is claimed is:
1. A method for improving the rate at which a driven cutting device
penetrates a masonry material such as concrete, granite or other
rock, sandstone, fired brick or a like material using a core drill,
said method comprising: passing a cooling stream of water to said
cutting device; and injecting a speed-enhancing composition into
said stream of water by a venturi-induced suction force.
2. A method according to claim 1 wherein said driven cutting device
is a saw.
3. A method according to claim 1 wherein said driven cutting device
is a core drill.
4. A method according to claim 1 wherein said stream of water is
passed to said cutting device by means of an injection device
having a through passageway with a constriction therein, and said
venturi-induced suction force is produced by said stream of water
flowing through said constriction.
5. A method according to claim 1 herein said composition is
introduced into said passageway via a side port in said device.
6. A method according to claim 5 wherein said composition flows
into said side port from a supply vessel via a flow control
valve.
7. A method according to claim 1 wherein said speed-enhancing
composition is a solution of a surfactant.
8. A method according to claim 7 wherein said surfactant is an
anionic compound.
9. A method according to claim 7 wherein said surfactant is
cationic compound.
10. A method according to claim 7 wherein said surfactant is a
non-ionic polymer capable of hydrogen bonding with water to produce
charge-neutralizing positive charge dipoles.
11. A method according to claim 10 wherein said non-ionic polymer
is a polyalkylene oxide or a polyacrylamide-based non-ionic
polymer.
12. Apparatus for improving the rate at which a driven cutting
device penetrates a masonry material such as concrete, granite or
other rock, sandstone, fired brick or a like material using a core
drill, said apparatus comprising: water-directing means for
directing a flow of water to said cutting device; and a venturi
liquid injection device having a water flow-through passageway,
inlet and outlet ports communicating with said passageway, and an
injection port communicating with said passageway, said outlet port
being connected to said water-directing means, said inlet port
being adapted to be connected to a water supply and said injection
port being adapted to be connected to a supply of a liquid
speed-enhancing composition; said injection device being designed
so that a stream of water flowing under pressure in said passageway
from said inlet port to said outlet port will produce a
venturi-induced suction force in said injection port sufficient to
cause injection of a liquid speed-enhancing composition into said
passageway via said injection port when said injection port is
connected to a supply of said composition.
13. Apparatus according to claim 12 wherein said injection
passageway has a constriction and said suction force is produced by
the flow of water under pressure through that constriction.
14. Apparatus according to claim 12 wherein said driven cutting
device is a saw.
15. Apparatus according to claim 12 wherein said driven cutting
device comprises a core drill.
16. Apparatus according to claim 12 further including flow control
valve means associated with said injection port for varying the
rate at which liquid is injected into said passageway by said
venturi-induced suction force.
17. Apparatus according to claim 16 wherein said injection device
comprises a housing having said through passageway and said
injection port, and said flow control valve is attached directly to
and supported by said housing.
18. Apparatus according to claim 17 wherein said flow control valve
means comprises an injection orifice and means for varying the
effective size of said injection orifice.
Description
[0001] This application is a continuation-in-part of copending U.S.
patent application Ser. No. 09/834,314, filed Apr. 13, 2001 for
Method And Apparatus for Sawing or Drilling Concrete.
[0002] This invention relates to provision and use of means coupled
to a masonry saw or core drill for facilitating the cutting or
drilling of concrete or other hard masonry materials.
BACKGROUND OF THE INVENTION
[0003] As used herein the term "masonry material" means and
includes concrete, steel-reinforced concrete, various kinds of rock
including but not limited to granite, sandstone, fired brick, and
tile. Special saws and drills are used for cutting and drilling
those materials. Masonry saws take various forms, including rotary
blade saws, ring saws, chain saws and wire saws. The drilling of
lengthy holes, e.g., holes 10-20 inches long, in structures or
structural components made of a hard masonry material is commonly
accomplished with a core drill (also called "core drill bit")
attached to a manually operated driver. A core drill commonly
comprises an elongate hollow tubular member, one end of which is
adapted to be releasably secured to the rotatable output shaft of a
driver that typically is an electrically powered or pneumatically
powered device. The opposite end of the tubular member is in the
form of or carries a tubular cutting head that may comprise diamond
or carbide particles embedded in a metal matrix. The core drill
derives its name from the fact that as it drills into concrete or
other dense material the interior of the drill fills with a
discrete cylinder, called a "core", composed of particles of the
material that is being drilled.
[0004] A common practice is to apply water to masonry saws and core
drills to enhance cutting and drilling. When water is applied to
saws, the sawing process is identified as "wet sawing". The water
is applied as a spray or jet(s) so as to flow over at least the
cutting edge portion(s) of the saw device, e.g., the teeth of a
chain saw, rotary saw blade or a wire saw. In the case of wet core
drilling, the water is injected into the core drill. Injection of
water into a core drill is accomplished by means of a coupling
device that either is a component of the driver or is a separate
component that may be detached when it is desired to perform dry
core drilling.
[0005] Applying water aids the sawing process by cooling the
cutting portion(s) of the saw device and removing saw residue from
the work area. Similarly, injecting water into the core drill aids
the drilling process by (1) cooling the drill, (2) facilitating
movement away from the cutting head of the particles produced by
the drilling operation so as to avoid unnecessary regrinding of
those particles, and (3) reducing masonry dust in the work area.
Consequently wet coring is preferred for renovation work in
inhabited buildings where it is necessary to maintain a dust free
environment. In such case it is common to surround the core drill
with a water collector that serves to collect water, including
suspended masonry particles, that escapes from the hole being
drilled in the masonry. In core drilling of concrete, water may
need to be supplied at a rate of as much as about 1 gallon per
minute to achieve the desired cooling, whereas in wet sawing of
concrete the water may need to be supplied at a rate as high as
about 4-10 gallons per minute.
[0006] The speed at which cutting and drilling proceeds in concrete
and other hard masonry materials is a function of the hardness of
the material being cut or drilled. The harder the material, the
lower the cutting or drilling speed, i.e., the rate of penetration
of the material by the saw or drill head. As used herein, the term
"cutting speed" identifies the rate, in terms of units of depth per
unit of time, at which a saw cuts through, or a core drill
penetrates, a masonry material. It is recognized that increasing
the cutting and drilling rates in concrete and other like
structural materials is desirable, if it can accomplished at
reasonable cost. It is known that the cutting of concrete may be
enhanced by applying an aqueous solution of one or more selected
compounds to the cutting tool as it was cutting. See, for example,
U.S. Pat. No. 5,196,401. However, there has existed a need for a
practical, dependable and relatively inexpensive way of supplying
masonry saw or core drill with cooling water containing a measured
amount of a cutting speed-enhancing compound.
[0007] My copending U.S. patent application Ser. No. 09/834,314,
cited supra, discloses an improved apparatus and method whereby a
stream of cooling water applied to a drill or saw is dosed with a
cutting speed-enhancing composition using a water-powered injector
pump apparatus that comprises a reciprocating injection pump driven
by a water motor. The cooling water is supplied under pressure to
the water motor from a suitable water supply, e.g., a municipal
water supply or a pressurized tank.
[0008] The apparatus disclosed in my copending patent application
is easy to use, works dependably and provides adequate control of
the rate at which the stream of cooling water is dosed with the
selected speed-enhancing composition. However, water-powered
injector pumps are relatively expensive and, because they have
moving parts, are handicapped by the potential of breakdown and the
cost and loss of time involved in repair. Care also must be taken
to avoid accidental damage to the pumps by personnel or mechanical
equipment operating at the same work site.
OBJECTS AND SUMMARY OF THE INVENTION
[0009] The invention stems from the desire to improve upon the
invention disclosed in my copending U.S. patent application Ser.
No. 09/834,314.
[0010] The primary object of this invention is to provide a method
and apparatus for introducing a speed-enhancing composition into a
stream of water applied to a saw or drill for cooling or rinsing
purposes that avoids the use of a water-powered injection pump.
[0011] A more specific object is to provide a method and apparatus
for dosing a stream of water applied to a masonry saw or drill that
does not require a pump for accomplishing the dosing function.
[0012] The foregoing objects are achieved by using a venturi-effect
chemical injector device to introduce a speed-enhancing compound
into a stream of water as it is being applied to a masonry saw or
core drill. In a first embodiment of the invention, a venturi-type
injector device is installed in a pipe or hose line connecting a
water supply to a masonry saw, and a speed-enhancing composition is
injected into the water line by the injector device. In a second
embodiment of the invention, a venturi type injection device is
connected in a pipe or hose line connecting a water supply to a
core drill that is attached to an electrically or pneumatically
powered driver, and a liquid speed-enhancing surfactant-containing
composition is injected into the water line by the via the injector
device. In both embodiments the speed-enhancing composition is
injected into the water line at a controlled rate as a function of
the flow in the water line. In both embodiments the speed-enhancing
composition is delivered only on a demand basis.
[0013] Other objects, features and advantages of the invention are
described or rendered obvious by the following detailed description
that is to be considered together with the drawings identified
below.
THE DRAWINGS
[0014] FIG. 1 is a schematic view of a saw system embodying the
present invention;
[0015] FIG. 2 is an exploded sectional view of one form of injector
device; and
[0016] FIG. 3 is a schematic view of a core drill system embodying
the present invention;
[0017] Like components are identified by like numerals in the
drawings.
DETAILED DESCRIPTION OF THE INVENTION
[0018] FIG. 1 relates to a preferred embodiment of the invention
and illustrates a conventional electrically powered saw 2 having a
rotary blade 4 that is powered by an electric motor 6 controlled by
a manually actuated switch 8. The blade 4 is provided with a
protective blade guard or shroud 10 that covers a portion of the
blade and has a port 12 therein through which cooling water may be
injected onto the blade when the latter is being used to cut
concrete or other masonry. The illustrated system also comprises a
dosing device in the form of an injector 16 that comprises a
housing 18 characterized by an inlet port 20, an outlet port 22,
and a side injection port 24. Preferably the injector is of the
venturi suction type that requires no moving parts for operation
and permits adjustment of the rate at which liquid is injected via
side injection port 24. Inlet port 20 is connected by a flexible or
rigid conduit, e.g. a hose or pipeline, to a suitable supply of
water 26 under pressure via a strainer 28 and a backflow preventer
30. The latter is for the purpose of preventing backflow of water
to the water supply. The strainer 28 is to intercept any
particulate matter in the water flowing to injector 16, e.g., dirt
particles, that might adversely affect operation of the injector
device. Preferably, but not necessarily, a main flow valve ("MV")
31 may be provided in the water supply line on the inlet side of
the injector to function as a shut-off valve when the same is not
in use. Outlet port 22 is connected to the saw shroud port 12 via a
check valve 32. Side injection port 24 is connected to a tank or
other vessel 34 connecting a supply of a selected chemical additive
via a flow control valve 36 and a strainer 38.
[0019] Venturi suction injectors are well known and may take
various forms, but essentially they are characterized by a through
bore that has a constriction and a side injection bore that
intersects the through bore at the constriction. When liquid flow
under pressure occurs in the main bore, a negative pressure is
created at the constriction, with the result that liquid in the
side injection bore is drawn into the through bore and mixes with
the liquid flowing in the through bore. The control valve may be
separate from the injector as shown in FIG. 1 or be attached
directly to the injector housing.
[0020] FIG. 2 illustrates one form of injector device that is
suitable for practicing the present invention. In this case the
injector housing 18 has a through bore identified generally by
numeral 42 that is characterized by inlet and outlet ports 20 and
22 at opposite ends of a constricted section 44. Housing 18 also
has a side injection bore 46 that connects with side port 24 and
intersects the constricted section 44 of through bore 42. The
diameter of side bore 46 is smaller than that of constriction 44.
The inlet and outlet ends of housing 18 have a reduced outer
diameter as shown at 47 and 48 that are adapted for connection,
e.g., by external screw threads (not shown), to other components of
the system shown in FIG. 1. The side port 24 is provided with an
internal screw thread 50 for attachment of an injection flow
control valve assembly 36A shown in FIG. 2.
[0021] The latter comprises a tubular housing 62 having a first
external thread 64 at its inner end and a second external thread 66
at its outer end. The external thread 64 permits the inner end of
housing 62 to be screwed into the side port 24 of housing 18.
Housing 62 has an internal flange 68 intermediate its opposite
ends, with the flange defining a fixed diameter orifice 70. Mounted
within housing 62 is a combination valve element/flow connector
unit 72 that consists of an inner valve section 74 having an outer
diameter that is substantially the same as or slightly larger than
that of orifice 70, an outer connector section 76 that is adapted,
e.g., by a ribbed outer surface or an external screw thread (not
shown), for facilitating a friction grip or screw thread connection
of the conduit (flexible hose or pipeline) that leads to additive
supply 34 as described above, and a large diameter intermediate
section 80 that is sized to make a close sliding fit with the inner
cylindrical surface of housing 62.
[0022] The unit 72 has an axial bore 82 that terminates in an end
wall 84 at its inner end and communicates with a
diametrically-extending discharge bore 86 that provides two
opposite side discharge ports whereby additive in bore 82 will flow
into housing 62 and then into orifice 70. A hollow knob 88
surrounds housing 62 and has an internal screw thread that makes a
screw thread connection with screw thread 66. The outer end of the
knob has an end wall 90 with a center opening that is slightly
larger than the maximum diameter of outer connector section 76, and
the latter extends through that center opening. The end wall 90
overlies and engages the annular outer end surface of intermediate
section 80. A compression coil spring 92 surrounds valve section
74, with one end of the spring engaged with the outer surface of
flange 68 and the other end engaged with the annular inner end
surface of intermediate section 80. The effect of spring 92 is to
urge the unit 72 outwardly away from housing 18 so as to maintain a
gap between the inner end of valve section 74 and orifice 70,
whereby liquid additive in axial bore 82 can be sucked into the
through bore 42 of housing 18 via bore 82, diametric bore 86,
orifice 70 and side bore 46.
[0023] Rotation of knob 88 functions to vary the gap between the
inner end of valve section 74 and orifice 70, with rotation of the
knob in one direction allowing the spring 92 to move the unit 72
move away from orifice 70, thus increasing the gap between the
valve section 74 and orifice 70, and rotation of the knob in the
opposite direction causing its end wall 90 to force the unit 72
toward orifice 70 so as to decrease the gap. Varying the size of
the gap between valve section 74 and orifice 70 has the effect of
varying the flow of liquid through orifice 70 into port 24. The
combination of valve section 74 and orifice 70 functions
essentially as a needle-type valve.
[0024] By way of example but not limitation, a venturi injector of
the type represented in FIG. 2 is available commercially in the
form of the Model YSSAINJ23 adjustable injector produced by General
Pump of 1174 Northland Drive, Mendota Heights, Minn. 55120. Other
forms of commercially available venturi type injectors also may be
use in practicing the invention, e.g., an injector as shown in U.S.
Pat. No. 6,453,926, issued Sep. 24, 2002 to G. A. Baker.
[0025] Operation of the system shown in FIG. 1 is straightforward.
When water under pressure flows from supply 26 through injector
housing 18, the pressure drop produced by constricted section 44
(the venturi effect) creates a suction force that draws additive
into the injector housing via the injector valve assembly 36A.
[0026] FIG. 3 shows an alternative embodiment of the invention
comprising a conventional core drill bit 100 and a conventional
electrically powered heavy-duty driver 102 for driving the drill
bit. The latter is shown in exploded relation to the driver for
convenience of illustration and description. The driver is shown as
having a power cord 104 for coupling it to an electrical power
source. The illustrated core drill bit 100 comprises an elongate
hollow cylindrical barrel 106 having a hollow cylindrical drill
head 108 at its forward end. Typically the drill head 108 comprises
diamond or silicon carbide particles embedded in a strong metal
matrix. Core drill bit 2 may take other forms without affecting the
invention. Core drill bits are available commercially from a number
of companies. One such company is Hilti, a corporation having a
place of business at 12330 E. 60th Street South, Tulsa, Okla.
74121.
[0027] The output end of the driver includes a chuck 110, which is
adapted to receive and releasably lock the core drill bit to the
driver. The design and construction of the driver is not critical
to this invention. Various forms of core drill drivers are
available commercially from a number of companies, including Hilti
(supra) and Flex Porter-Cable, a company having a place of business
at 4825 Highway 45 North, Jackson, Tenn. 38305.
[0028] A water intake device 112 is interposed between core drill
bit 102 and chuck 110. The water intake device 112 is designed to
inject water into the interior of the core drill as it is rotated
to execute a drilling operation. For this purpose water intake
device 112 has an inlet port 114 whereby water can be delivered
from a source of supply 116 into water intake device 112 and from
there into the core drill bit during a drilling operation. As with
the embodiment of FIG. 1, the water supply 116 may be a domestic
water supply. As used herein, the term "domestic water supply" is
intended to include municipal and non-municipal water sources,
including commercially or privately owned wells, that are capable
of providing a continuous flow of water under a suitable near
constant or regulated pressure.
[0029] Water intake device 112 may be a separate component that can
be removed when it is desired to perform dry core drilling;
alternatively it may be built as an integral part of the chuck
assembly. Thus, for example, the water intake device may take the
form of the water swivel attachment sold by Hilti under the
designation "Hilti DD 100 5/8" Water Swivel" which is adapted for
use with the Hilti DD-100 Drill (i.e., driver). The Hilti water
swivel functions to rotatively connect a core drill to the driver's
chuck and also to inject water into the core drill bit.
Alternatively, and further by way of example, the driver 104 and
water intake device 112 may take the form of the Flex Porter-Cable
Model BHW 812 V electrically-powered driver which has a built-in
water intake. Whether the water intake device is a separate
component or is an integral part of the driver is not critical to
the invention, and the water intake device may take various forms
so long as it satisfies the requirement of providing means for
directing water into the core drill bit as the latter is driven by
the driver into concrete or other masonry material.
[0030] The system of FIG. 3 further includes the use of a dosing
device in the form of a venturi-type injector 16 as described above
for introducing a selected chemical additive to the water that is
supplied to water intake device 112. Port 114 is connected to the
water supply 26 via a backflow preventer 120, a strainer or filter
122, a main valve ("MV") 124, injector 16 and a check valve 126.
The backflow preventer 120 and strainer 122 prevent backflow of
water to the water supply and removal of any particulate matter
that might adversely affect operation of the injector device. Check
valve 126 prevents backflow of solid particle from the core drill
to the injector.
[0031] Operation of the system shown in FIG. 3 is essentially the
same as that of FIG. 1. Flow of water under pressure from water
supply 116 causes additive to be injected into the water stream
flowing to water intake device 114, according to the setting flow
control valve 36. It is to be noted that valve 36 in both FIG. 1
and FIG. 3 the valve 35 may be set to a fully closed position,
whereby no additive will be injected into the water stream flowing
to the cutting tool.
[0032] As has been noted in my copending application Ser. No.
09/834,314 (which is incorporated herein by reference) it has been
determined that addition of a surfactant to the cooling water for a
concrete saw or core drill can provide a substantial increase in
the speed at which such tools penetrate concrete, and also in
reduced wear of the cutting elements of the tool. Accordingly the
liquid additive supplied by operation of the proportioning device
comprises an aqueous solution of one or more surfactants. The
invention is not limited to particular surfactants, and the
surfactants may be anionic or cationic materials. Surfactants like
those used in household and industrial detergent compositions may
be used with the invention to improve drilling and cutting speeds.
Examples of anionic surfactants that are useful with the invention
are alkyl benzyl sulfonate, alkyl sulfates derivatives of coconut
oil and tallow, sodium dodecyl sulfate, and alkyl ether sulfate. An
example of a suitable cationic surfactant is trimethyldodecyl
ammonium chloride. Still other cationic surfactants are known to
persons skilled in the art. Preferably the surfactant is a
non-ionic polymer capable of hydrogen bonding with water to produce
charge-neutralizing positive charge dipoles, e.g., a polyalkylene
oxide such as polyethylene oxide and a polyacrylamide-based
non-ionic polymer is preferred. The use of such non-ionic polymers
in relation to cutting or drilling rock or concrete, and the
resultant benefits of increased cutting speed and reduced cutting
element wear, is discussed in detail in U.S. Pat. No. 5,196,401,
issued Mar. 23, 1993 to W. H. Engelmann et al. The minimum
concentration of such polymer in the aqueous solution injected into
core drill 2 should be about 1-3 parts per million. That
concentration is easily accomplished with a proportioning pump of
the type described. Still other surfactants that may be used in
drilling or cutting concrete or like material according to the
invention are disclosed by U.S. Pat. No. 5,807,810, issued Sep. 15,
1998 to M. Blezard et al. The teachings of U.S. Pat. Nos. 5,196,401
and 5,807,810 regarding use of surfactants for cutting materials
like concrete and rock are incorporated herein by reference. Of
course, the optimum concentration of surfactant in the aqueous
solution may vary according to the specific surfactant used.
[0033] The advantage of using an injector-type dosing device of the
character described is that it facilitates injection of small
amounts of additive solution into a stream of water flowing under a
high pressure, is rugged, has a long useful life since it has no
moving parts, and is relatively inexpensive. By way of example,
venturi-type injectors are available that an accommodate water flow
in the range of 1-300 gallons per hour. This is important not only
from the standpoint of enhancing the cutting speed, but also from
an economical basis, since in using saws to cut concrete walls or
floors, the consumption of water may vary substantially depending
on various factors, including the hardness of the masonry material.
Available injectors of the type described are capable of injecting
an additive solution into the water stream flowing through the
injector at a controlled rate so as to provide a selected ratio of
additive flow to water stream flow. By appropriately diluting the
additive solution it is possible to limit the concentration of
speed-enhancing compound injected into the flowing water stream to
within, for example, the range of 1-150 parts per million.
[0034] An additional advantage is that the presence of a flow
control valve for injection of additive via the side injection port
makes it possible to increase or decrease the rate of introduction
of additive into the cooling water fed to the saw or core drill
without changing the concentration of additive in the solution
contained in supply vessel 34. This aspect is important since the
rate of flow of water through the injector must be kept above a
minimum level in order achieve the desired venturi-effect injection
of additive. Additionally the invention provides a benefit of
economy in that the additive is supplied to the sawing or drilling
operation only when water is flowing to the saw or drill.
Consequently, and particularly considering the relative high cost
of certain surfactants, the use of the liquid surfactant additive
is controlled. A further advantage is that use of an injector
device of the type described in place of an injection pump reduces
equipment cost.
[0035] Obviously the invention may be practiced otherwise than as
described above and illustrated in FIGS. 1-3. Other forms of
injection may be used. Also strainers 28 and 122, backflow
preventers 30 and 120, and main control valves 31 and 124 may be
omitted where there is no need for them. The injector also is
applicable to pneumatically powered tools in place of electrically
powered tools. Also the invention may be applied to different forms
of drills and saws. For example, although saw 2 is represented as a
rotary blade saw, it is to be understood that the invention may be
practiced with other types of saws for cutting concrete, notably
ring saws, chain saws and wire saws. The invention also is not
limited in its application to saws employed at construction work
sites, but extends as well to saws used in quarries and various
stone work shops.
[0036] It is to be noted also that the invention is not limited to
supplying cooling water. Instead, for example, the cooling medium
supplied to the proportioning pump 18 could be a light oil, with
the proportion of speed-enhancing surfactant compound and the
selection of speed-enhancing compound being adjusted according to
whether oil or water is being used as the cooling medium.
[0037] As used herein, the term "conduit" herein shall mean and
include, where the context so admits, a hose, tubing or pipe. Also
the term "cutting device" as used in the claims in intended to
embrace and include core drills and saws and, where the context so
admits the drivers for such cutting devices. The cutting elements
of a saw are its cutting teeth, and the cutting elements of a core
drill are the teeth of and/or the diamond or silicon carbide
particles carried by the cutting head of the drill.
[0038] Still other modifications and variations of the invention
will be obvious to persons skilled in the art from the foregoing
description and the FIGS. 1 and 2.
* * * * *