Note: Descriptions are shown in the official language in which they were submitted.
CA 02600644 2009-03-12
PNEUMATIC TOOL HAVING INTEGRATED ELECTRICITY GENERATOR
WITH EXTERNAL STATOR
Field of the Invention
[0001] The following relates generally to pneumatic tools with integrated
electricity generators and more particularly to an integrated electricity
generator for a
pneumatic tool with a stator that is positioned on the outside of the
pneumatic tool
housing.
Background of the Invention
[0002] Conventional pneumatic tools, such as a pneumatic wrench, sander or
grinder typically include a fluid driven motor comprised of a rotor having
sliding
vanes and mounted for rotation on ball bearings enclosed within a pressure-
tight tool
housing. The ball bearings are supported by front and rear end plates
positioned on
each end of a motor cylinder having an offset annular bore, relative to its
external
diameter and running parallel to the cylinder length. The rotor runs
longitudinally
through offset annular bore of the cylinder, in non-concentric alignment with
an
internal wall and concentric alignment with the external wall thereof, to
provide a
chamber internal to the cylinder bore along the length of one side of the
rotor for
receiving pressurized fluid, such as compressed air, entering from an inlet
port leading
into the chamber. The pneumatic tool housing is a pressure-tight casing
alternatively
referred to as a motor housing.
[0003] Lengthwise slots in a number of equidistant locations about the
circumference of the rotor for receiving the vanes are known as rotary vane
slots. The
rotary vane slots each support a phenolic (or plastic) vane that radially
slides within
the slots as the rotor rotates, thereby enabling consistent contact of the
outer edges of
the vanes with the internal wall of the chamber. In combination with
lubricating oil,
when the rotor is rotating due to a flow of pressurized fluid, the sliding
vanes act as
rotating "seals" forming a boundary in the pressurized chamber at the union of
the
vanes planar surface areas with rotor slot walls and vane outer edges with
cylinder
wall as vanes enter and exit the pressurized chambered area. Sometimes vanes
are
biased radially outward in the rotor slots to maintain contact with the
cylinder wall by
spring tension. Springs are provided between the base of the slot and air-vane
to
maintain a sealed chamber upon startup, thereby so eliminating cogging or
stalling
prior to inertial momentum. Each time a vane enters the chamber, it receives
pneumatic force upon a high-pressure side of its extended planar surface, due
to a
CA 02600644 2009-03-12
-2-
flow of pressurized fluid that is entering behind it from an adjacent inlet
port usually
situated on the circumferential edge of the motor cylinder at the start of the
chambered area. The inlet port communicates maintain a sealed chamber upon
startup, thereby so eliminating cogging or stalling prior to inertial
momentum. Each
time a vane enters the chamber, it receives pneumatic force upon a high-
pressure side
of its extended planar surface, due to a flow of pressurized fluid that is
entering
behind it from an adjacent inlet port usually situated on the circumferential
edge of
the motor cylinder at the start of the chambered area. The inlet port
communicates
with an inlet passage and valve body in the tool housing.
[0004] The high-pressure fluid passes through the cylinder walls, surmounting
mechanical resistance at the air vanes in the chambered area, to reach a low-
pressure
state at exhaust ports in the cylinder wall. The exhaust ports are generally
located
beyond a specified degree of arc from the inlet of the pressurized chamber,
thereby
causing the rotor to forcibly rotate in a direction from the pressurized inlet
towards
exhaust ports within the motor cylinder and tool housing. A pinion on the
rotor's
shaft transmits rotational force to a planetary gear set to provide useful
torque
conversion from high-speed rotation at the working end of the tool. Some
pneumatic
tools make use of gearing in order to transmit the rotational force to the
working end
of the tool, while others do so simply by employing a threaded shaft and a
collet, or
other means appropriate to the primary application of the tool.
[0005] United States Patent No. 4,678,922 (Leininger) discloses an apparatus
for
generating electricity using the flow of pressurized fluid such as air in a
pneumatic
tool by way of a magnetic coupling between a specially designed rotor and a
stator.
Magnetic means are affixed to the tool rotor, and thereby cooperate during
rotation
with a stator mounted in the tool housing, motor cylinder or bearing end
plate(s) to
induce electrical current in the coils of the stator. The `922 disclosure thus
provides
an integrated, self-contained and self-powered lighting source for
illuminating a
workpiece upon which the pneumatic tool is working. Various improvements have
been made to integrated electricity generators in order to improve their
electrical
output, longevity, usability, efficiency, cost and manufacturability, and to
reduce their
size. Examples of
CA 02600644 2008-06-12
-3-
such improvements may be found in U.S. Patent Nos. 5,525,842 and 7,095,142
(both to
Leininger) in which various configurations of rotor, stator, power
distribution and light
source are provided.
[0006] While the contributions of the above-mentioned references are
significant,
improvements are of course desired. For example, both the rotor and stator of
prior art
integrated electricity generators are inside the tool housing such that they
are exposed to
the compressed air and fluids containing lubricating oil mixed with moisture
in the
pressurized air stream flowing therethrough. The stator and particularly the
coil winding
therefore have to be potted or otherwise specially treated in order to protect
sensitive
electrical components. Furthermore, each device to which the generated
electricity is
supplied (i.e., incandescent lamps, light emitting diode (LED), active RFID
tags and
other electronic devices etc.) is typically employed by, or presents a user
interface
external to, the tool housing. Electrical lead wires conducting current from a
stator must
therefore pass from the pressurized interior of the tool housing, typically at
90 to 100 +
pounds-per-inch2 (psi) during operation, to exterior zones typically at normal
atmospheric pressure of zero psi, via feed-through conduits. To prevent leaks
of
pressurized fluid, an additional manufacturing step is typically necessary to
provide
hermetic sealing around the feed-through conduits. Additionally, during tool
assembly
and service a labor-intensive procedure is needed to resolve the physical
placement of
lead wires through a motor bore, tool housing and feed-through conduit from an
internal
stator.
[0007] Furthermore, it is an electronic challenge to provide a secure,
vibration
damped environment for mounting printed circuit boards containing sensitive
integrated
circuit (IC) components and sensors, whether on a metallic bodied tool surface
or in a
cavity thereon, while also providing a nonconductive and static-free and dry
environment. Experience in the art teaches that pneumatic motor resonations
can
produce deleterious effects on some electronic components hard-mounted onto
the tool
housing.
[0008] It is an object of an aspect of the following to provide a novel
integrated
electricity generator for a pneumatic tool having a stator that is positioned
external to the
pneumatic tool housing.
CA 02600644 2010-06-29
-4-
Summary of the Invention
[008a] According to an aspect of the present invention, there is provided
a tool comprising: a nonmagnetic tool housing; a cylindrical rotor inside the
tool housing and rotatable in response to a flow of pressurized fluid through
the tool housing; magnets mounted in the rotor; a stator on the exterior of
the
tool housing, the stator dimensioned to cooperate with the magnets to, upon
rotation of the rotor, generate electrical current for supply to a load, the
stator
comprising: an inductor core having opposing ends connected by a middle
portion; a coil wound around the middle portion, where both the inductor core
and coil are configured to be arced between the opposing ends about the axis
of rotation of the rotor, and the inductor core is configured to provide a
consistent gap between the face of the inductor core and the face of each
magnet while each magnet is being rotated between positions proximal the
opposing ends, the inductor core having a length to enable its opposing ends
to
each be simultaneously radially aligned with a respective magnet in the rotor
to complete a magnetic circuit through the inductor core.
[008b] According to another aspect of the present invention, there is
provided a stator for cooperating with a rotor having magnets mounted therein
and disposed within a tool housing of an integrated electricity generator of a
tool, the stator configured to be disposed on the exterior of the tool housing
and comprising: an inductor core having opposing ends connected by a
middle portion; a coil wound around the middle portion and having leads for
supplying current to a load external to the tool housing, where both the
inductor core and coil are configured to be arced between the opposing ends
about the axis of rotation of the rotor, and the inductor core is configured
to
provide a consistent gap between the face of the inductor core and the face of
each magnet while each magnet is being rotated between positions proximal
CA 02600644 2010-06-29
-5-
the opposing ends, the inductor core having a length to enable its opposing
ends to each be simultaneously radially aligned with a respective magnet in
the rotor to complete a magnetic circuit through the inductor core.
[008c] The integrated electricity generator disclosed herein provides several
advantages. In particular, it is not required to pass lead wires through feed-
through conduits in order to generate electricity for use outside of the tool
housing from the relative movement of the rotor and the stator.
[0009] Furthermore, hermetic sealing previously required for feed-through
conduits is not required. It will be understood that obviating the lead wires
also
obviates the related manufacturing steps necessary for their placement.
[0010] Overall circuit resistance is also reduced, improving the operational
electrical efficiency of power distribution to storage components, integrated
circuits and LEDs. Because the tool cover is configured to support and align
the
inductor element and circuitry of the stator with respect to the rotor,
construction
of the pneumatic tool itself is further simplified.
[0011] Yet another advantage is that the stator does not depend, rely on, or
affect any of the engineered mechanical tolerances of existing air tool
designs.
Conversely speaking, the stator component dimensions are not governed by
critical tolerances of the mechanical parts designed to drive a pressurized
fluid
driven tool efficiently.
[0012] As compared to prior art methods directly involving modifications to
motor parts and in particular, an end plate supporting a rotor, this approach
does
not constrict stator size (or output) to minimal air-motor volumes or to
limits
restricted by the size of internal motor elements. The degrees of freedom to
CA 02600644 2009-11-26
-6-
designing an appropriate sized stator to fulfill a specific electronic
objective are
therefore increased, allowing design to a higher degree to be informed by the
external boundary of the tool or what may otherwise be deemed commercially
acceptable tool aesthetics.
[0013] Other aspects and advantages will become apparent from the details
of construction and operation as more fully hereinafter described and claimed,
reference
Brief Description of the Drawings
[0014] Embodiments will now be described more fully with reference to the
accompanying drawings, in which:
[0015] Figure 1 is an exploded view of two pneumatic tools having
integrated electricity generators, according to the prior art;
[0016] Figure 2 is a view of a pneumatic tool having an integrated
electricity generator with an external stator, with exploded and disassembled
views of components thereof;
[0017] Figure 3 is a view of a rotor for an integrated electricity generator
from front and perspective views, and a magnet for receipt in a groove
thereof,
[0018] Figure 4 is a perspective view of a magnet for receipt by a
corresponding groove in a rotor body;
[0019] Figure 5 is an exploded view of an air motor, according to an
embodiment;
CA 02600644 2009-11-26
-7-
[00201 Figure 6 is a perspective view of the interaction between rotor
magnets.
CA 02600644 2008-06-12
-8-
and a stator adapted for positioning on the outside of the tool housing;
Figure 7 is a top view of an elongated working-side view of a pneumatic
ratchet tool cover and a close up cutaway view of the tool cover with an
embedded
inductive luminaire;
Figure 8 is a perspective view of a pneumatic ratchet wrench that may be
enclosed in a two-part plastic protective tool cover, shown disassembled;
Figure 9 is perspective view of the pneumatic ratchet wrench of Figure 8
with the two-part protective tool cover just prior to assembly;
Figure 10 is a perspective view of the pneumatic ratchet wrench of Figure
8 with the two-part protective tool cover having been assembled;
Figure 11 is a perspective view of a conductive tool cover of single-piece
construction for a pneumatic ratchet wrench, according to an alternative
embodiment;
Figure 12 is a perspective view of the conductive tool cover of Figure 11,
one segment of which is shown pivotable with respect to another;
Figure 13 is a perspective view of the conductive tool cover of Figure 12
having received the pneumatic ratchet wrench and with lights in the pivotable
segment having been illuminated;
Figure 14 is a flat, flexible printed circuit (FFC) connecting LEDs and
integrated circuit (IC) chip for incorporation into a protective flexible tool
cover;
Figures 15 and 16 are elevation views showing a conductive tool cover
and positioning of the FFC of Figure 14 for use with an LED enhanced micro
display;
Figure 17 is a perspective view of a pneumatic tool with a conductive tool
cover having embedded electronics for flashing micro display and work surface
illumination;
Figure 18 shows an inductive luminaire connected to remote storage by
FFC, according to an alternative embodiment; and
Figure 19 is a perspective view of safety glasses incorporating radio
frequency (RF) and infrared (IR) transmitters for wireless control of safety
awareness
features embodied with or the operation of a power tool.
CA 02600644 2008-06-12
-9-
Detailed Description of the Embodiments
[0021] For the purpose of this specification, it will be clearly understood
that the
word "comprises" means "including but not limited to" and that the word
"comprising"
has an equivalent meaning.
[0022] Figure 1 shows exploded views of two prior art air-motor integrated
electric
generators and supporting components generally at 10 and 50. It can be seen
that
physical wires 12 are required to carry electrical current from the stator
including the
inductor 14 and supporting circuitry 16 that is positioned within the
pressurized tool
housing (not shown in Figure 1) through to the low pressure exterior of the
tool housing.
The electrical current supplies respective light ring luminaire 18 for use
outside of the
tool housing to light the immediate surface area of a workpiece. The
supporting circuitry
of the stator is potted (epoxy encapsulated) to prevent interference of
moisture and high-
pressure air with its sensitive electrical components. Not shown in Figure 1
but required
in such prior art devices is hermetic sealing at feed-through conduits in the
tool housing
to prevent undue egress of high pressure air through the conduits.
[0023] Figure 2 shows the general configuration of a novel pneumatic tool in
the
form of an air ratchet wrench 100 incorporating an integrated electricity
generator,
according to an embodiment. Air ratchet wrench 100 includes an air inlet 101
to allow a
pressurized fluid such as compressed air to enter inlet passages within its
cast aluminum
tool housing 115. Tool housing 115 has general dimensions of about 5.0 inches
in
length (L) x 1.4 inches outside diameter (OD). Tool housing 115 has a
generally
concentric center-bore for receiving a cylindrically shaped pre-assembled air
motor with
said center-bore having dimensions of about 3.150 inches L x about 1.190
inches inside
diameter (ID). An air inlet valve-actuating lever 102 enables a user to
control a
mechanically operated or alternative switchable solenoid inlet valve (not
shown), and
hence the flow of compressed air entering the tool housing via air inlet 101.
A discrete
high visibility lighted brand name, trade mark, logo, private user name or
hazard
warning label with supporting drive circuit, is mounted in a recessed area on
the surface
of a polyurethane (or other flexible material) or molded rigid plastic
nonconductive tool
cover 117 that receives aluminum tool housing 115.
[0024] The integrated electricity generator has a rotor 103 that is rotated
upon
application of compressed air via air inlet 101 and valve onto sliding vanes
118 slideably
CA 02600644 2008-06-12
-10-
mounted in respective slots 103a of the rotor body. In the present embodiment,
the rotor
body of rotor 103 has general dimensions of about 1.494 inches L x about 0.806
inches
OD. Rotor 103 also has a plurality of grooves 104 in a number of equidistant
locations
about its circumference (i.e., between vane slots 103a) to receive and retain
respective
magnets 105.
[0025] The integrated electricity generator also has a stator that comprises
an
inductor element 107 disposed on the outside of (i.e. on the opposite side of
the tool
housing from the rotor, or "external to") the tool housing 115 and physically
supported
by tool cover 117. Inductor element 107 includes a generally flat I-shaped
inductor core
110 having an overall end-to-end dimension of about 1.304 inches with a
thickness (T)
of about 0.025 inch that is further curved lengthwise, or "arced" in the
geometric sense.
A coil 109 of magnet wire of either flat or round conductor of pure copper
having an
American Wire Gauge number of from 34 to 36 gauges is wound around inductor
core
110. As can be seen, magnet wire of coil 109 is wrapped orthocyclically (even
layers) to
around 350 to 400 turns, around the central portion (space between opposing
ends) of the
inductor core 110. The dimension of the central portion of I-shaped core 110
is about
0.875 inch L x about 0.225 inch W. Each of the inductor ends of the I-shaped
inductor
core 110 has side-to-side (opposing ends of "I" areas perpendicular to the
central core)
dimensions of about 0.800 inch (corresponding to a rotor magnet length of 1.00
inch).
[0026] Inductor core 110 is made of die-stamped magnetically saturable
electrical
steel, such as Silicon Iron magnetic alloy used as core laminations in typical
transformers, motors or alternators. If overall weight of a tool is to be kept
to a
minimum, inductor 110 can be alternatively formed from thinner laminations of
high
permeability aircraft grade Vanadium Cobalt alloy. The physical arc of
inductor core
110 may be described as being about a circumference of an imaginary cylinder
having a
radius (R) of about 0.77 inch generally arced through 90 degrees of said
radius. This
inductor size will work for a pneumatic tool, the nonmagnetic housing of which
has an
outer diametrical dimension no greater than 1.4 inches in the radially
adjacent
circumference surrounding the rotor magnets (or magnetic field). The physical
arc of
inductor is generally coaxial with the axis of rotation of rotor 103. Ends of
coil 109 are
solder dipped to square-pin terminal type circuit board header pins 108 of
about 0.025
CA 02600644 2008-06-12
- 11 -
inches so as to adapt to PC board through-hole mounting means of a printed
circuit
board 111.
[0027] Luminaire 106 receives current from conductive traces of printed
circuit
board 111 plane that are connected to header pins 108. Luminaire includes LEDs
114
and supporting circuitry including further a single rectifier diode 112 and an
ultra-
capacitor 113 storage means. Multiple LEDs 114 may be substituted with a
single LED
to provide 100 - 107 lumens at 350 mA, such as a CREE Xlamp 7090 XR-E Series
LED
(not shown), which is more than enough light for illuminating a workpiece
during
operation of the pneumatic tool in dimly lit work places.
[0028] Single rectifier diode 112 is a standard recovery axial lead rectifier
diode
such as a 1N4001, or a smaller surface mount equivalent ultra fast silicon
rectifier such
as US 1 A by PanJi. The single diode provides rectification to half-wave
direct current
(DC) from raw variable frequency input alternating current (AC) delivered
directly by
the stator coil 109. Half wave DC is known to be suitable for throughput to a
storage
capacitor 113, which smoothes the rectified current upon discharge to provide
generally
uniform DC to a load.
[0029] Alternatives to ultracapacitor 113 may include rechargeable battery
such as a
high energy density Nickel Metal Hydride (NiMH) or thin-cell Lithium Polymer
(LiPo)
battery as is well known in portable electronics applications. One newly
emerging
rechargeable battery that appears to be a likely substitute for a fast
charging
ultracapacitor is the ultra-thin, flexible, super fast charging, high power
density and
environmentally friendly device, known as an organic radical battery (ORB)
announced
and under development by NEC in 2005. Such a storage device could be
integrated with
inductor element 107 to form a magnetically reactive power charge-discharge
source that
would provide electricity for as long as the tool remained operative.
[0030] In general, capacitors that provide smooth operating parameters for
illuminating a work surface with high brightness white emitting LEDs, can
range in
value from a single Farad (F) through 4 F depending on the desired time
constants for
charging and discharging cycles. Commercially available IF Aerogel Series B
capacitor
by PowerStor will yield up to a minute of intense light using two 5mm Nichia
NSPW500BS LEDs, whereas a 4F Maxwell Technologies PC5 will more than double
the IF discharge period for these lamps. The generally uniform DC current is
provided
CA 02600644 2008-06-12
-12-
to a load, which according to this embodiment are light emitting diodes (LEDs)
114,
used for illuminating a workpiece. More sophisticated tool related electronic
hardware
such as that which can provide digital torque calculation on fasteners
embodied with an
air powered wrench, that calls for computer or memory will require full wave
bridge
rectification to inputs in place of single diode 112 and higher energy density
storage
means to support prolonged operations in place of specified capacitors.
[0031] During operation of air ratchet wrench 100, rotor 103 rotates in
response to
application of pressurized air, causing magnets 105 to rotate within tool
housing 115
relative to stationary inductor element 107 of the stator positioned on the
outside of tool
housing 115. Electrical current is thereby caused to flow entirely on the
outside of tool
housing 115 in the copper magnet wire of coil 109 for supply to storage
capacitor 113
and ultimately for powering LEDs 114 of luminaire 106.
[0032] Figures 3 and 4 illustrate rotor 103 and a magnet 105 for receipt
therein.
Magnet 105 is a permanent magnet (preferably formed of a high-grade Neodymium-
Iron-Boron pressed powdered metal, or "NdFeB"). Alternatively, magnet 105
maybe
formed of Samarium Cobalt (SmCo). NdFeB and SmCo are known as rare earth
magnets, which are presently some of the most powerful permanent magnet
materials
commercially available. Furthermore, rare earth magnets are advantageously
very
difficult to demagnetize, making them very suitable for use in the vibration-
intensive
environment of a pneumatic tool motor. One drawback of the use of rare earth
magnets
is their potentially lower resistance to corrosion, although with pneumatic
tools this
detrimental corrosion is attenuated somewhat by the normal use of tool
lubricating oil.
To further inhibit the amount of contact by water moisture and air typical of,
for
instance, a compressed air stream, it is beneficial to coat magnet 105 by
using a
corrosion-resistant material such as an epoxy, catalytic automotive epoxy
sealant, zinc
chromate or epoxy-chromate. Alternatively, magnet 105 may be plated using
nickel
electrodeposition.
[0033] Magnet 105 has a North-South or South-North field perpendicular to its
length and width, and is dimensioned to complement and be securely retained by
rotor
103. The physical size of the magnet required to generate electricity depends
partly on
the Maximum Energy Product (BHmax) of the magnet material measured in
megaGauss
Oersteds (MGOe), commercially defined by a grade number designation.
Generally, the
CA 02600644 2008-06-12
- 13-
higher the MGOe grade number, the less magnet volume (surface area) will be
required
for a target application. For a tool embodiment having a housing 115 and rotor
body 103
of previously described dimensions, a 42 MGO magnet having rectangular
dimensions
of about 1.0 inches L x about 0.250 inch W x about 0.125 thick (T) provides a
suitable
excitation field for general work surface illumination purposes. The "M"
arrowed in
Figure 4 shows the polar orientation of magnet 105. A plurality of magnets 105
(four
magnets 105 in Figure 4) with alternating polarities is retained securely
within machined,
cast or molded grooves 104 of a machined, press-powdered metal (PPM) or
injection
molded plastic rotor 103. More particularly, the magnets 105 at 0 degrees and
180
degrees have respective North poles facing the outside of rotor 103, whereas
the magnets
105 at 90 degrees and 270 degrees have respective South poles facing the
outside of
rotor 103. Secure retention of the magnet 105 in the rotor body 103 is
important due to
high-speed acceleration rates and momentums reached during operation of air
ratchet
wrench 100. It is primarily the shapes of magnet 105 and mating groove 104
that
enables magnet 105 to be received by and retained within groove 104 when
rotational
momentum causes maximum opposing inertial forces to act upon rotor 103 thereby
forcing magnets 105 outward from the axis of rotation of rotor 103.
[00341 In particular, magnet 105 has a flat face 105a on one side, and a
curved (or
"rounded") side 105b opposing the flat face side 105a. Magnet 105 also has a
flat base
side 105c, and a curved (or "rounded") top side 105d opposing flat base side
105c with a
curve radius that permits it to be generally continuous with the external
surface of rotor
103 when magnet 105 is received by groove 104. Magnet 105 also has oblique
sides
105e that are not perpendicular to flat base side 105c and generally mirror
oblique sides
104a of groove 104. Magnet 105 and groove 104 thereby mate in a generally
dovetail
configuration. Magnet bonding adhesive provides additional retention of each
magnet
105 within its respective groove 104.
[00351 It can be seen that rotor 103 is generally of a conventional pneumatic
tool
configuration, with the exception that it further includes grooves 104. As
will be
familiar to the skilled worker, a hobbed pinion 103b on the shaft of rotor 103
is for
driving gears at the working end of the air ratchet wrench 100. A rear bearing
axial shaft
103c protrudes into the rear end plate (not shown in Figure 3) supported by a
ball
bearing (not shown in Figure 3). It can be seen in the end-view of Figure 3
that the
CA 02600644 2008-06-12
-14-
machined, generally dovetail-shaped groove 104 cooperates with magnet 105 to
retain
magnet 105. The alternating polarities 105e of magnets 105 are also shown.
[0036] Figure 5 is an exploded view of an air motor having conventional
components with the exception of rotor 103, which has been modified to receive
and
retain magnets 105, and a change from conventional ferrous to nonferrous
material
composition of an air cylinder 119. Air cylinder 119 is nonmagnetic and is
formed of
Pressed Powdered Metal (PPM) containing sintered 300 series stainless steel.
The PPM
formulation can optionally contain a lubricant impregnated into the walls of
cylinder 119
to attenuate friction between the contact surfaces of sliding vanes 105.
Cylinder 119 can
be a separate component, as is the case in most conventional air tool
constructions, or
part of a molded over "inner" tool housing; similarly demonstrated in U. S.
Patent
5,017,109 entitled Cylinder And Housing Assembly For Pneumatic Tool to
Ingersoll-
Rand. In the `109 patent, a nonconductive plastic composite is molded directly
over the
external surface of an air motor cylinder (in this case a nonmagnetic cylinder
119)
effectively merging it with tool housing 115. Such a construction can be
utilized to
create an electronics-supporting tool casing. To fully encase and protect
electronic
arrangements situated on the external surface thereof, a second composite
housing, in the
form of a sleeve, is formed to slide over the electronics-supporting inner
tool housing
thereby forming a nonconductive protective shell to shelter stator, circuitry
and other
onboard electronics.
[0037] A high rpm front motor bearing 120 is concentrically retained by a
front
motor bearing end-plate 121. A second high rpm rear motor bearing 122 is
concentrically retained by a rear motor bearing end-plate 123. A flywheel 124
is
disposed on the end of the shaft, where a retaining clip 125 maintains a
positive stop
position of flywheel 124. It will be noted that magnets 105 in Figure 5 have a
different
configuration than those shown in Figures 3 and 4 and are therefore retained
in grooves
104 having a correspondingly different configuration. However, it will be
understood
that the configurations of magnets 105 and grooves 104 shown in Figures 3 to
6, a
plastic rotor with magnets molded in or a rotor comprised of PPM magnetic
material
may be considered alternatives. Therefore, while one may provide certain
advantages
over the other, the principles of operation of the alternative embodiments of
the
integrated electricity generator disclosed herein are generally the same.
CA 02600644 2008-06-12
-15-
[0038] Figure 6 is a graphic representation of magnetic flux field as
inductive
coupling occurs between magnets 105 and inductor element 107. A flux transfer
path
represented by the lines shown in the GAP area may be considered for ease of
understanding as a magnetic analog to the electrical transfer of energy
through wire at
the feed-through conduits of prior art structures referred to herein. The
lines 41 drawn
alongside inductor element 107 show magnetic permeation of inductor core 110
at peak
AC electrical cycle represented by its sinusoidal waveform. It can be seen
that magnets
105 are radially aligned with their magnetic orientations, depicted by
magnetic N and S,
arranged about an axis with respect to a center line corresponding to the axis
of rotation
of rotor 103. Inductive element 107 is proximal to magnets 105 when stator
comprising
luminaire 106 and inductive element 107 is aligned and supported in its
intended resting
position by tool cover 116 on the external surface of air ratchet wrench 100.
"GAP", the
space between the respective magnetic pole surfaces of magnet 105 and those of
flux
absorbing ends of inductor core 110, is a magneto mechanical critical
dimension,
because distance affects strength of a magnetic field measured in gauss,
directly
affecting induction within inductor core 110. The alternating magnetic field
sweeps into
the inductor core 110 providing the source for electromotive force (EMF) in
the coil wire
at the top of each cycle of polarity change. For grade MGO 42 permanent
magnets, an
efficient generator embodiment works through a GAP of about 0.290 to about
0.330
inches between face of magnet 105 and face of end surfaces of inductor element
107.
Variation in these dimensions from this scale can be slightly greater by up to
an
additional 0.035 inch, however, for efficiency should be kept as minimal as
possible
because magnetic field strength of a magnet is approximately proportional to
the inverse
cube of a distance (in this case measured in inches) from the magnet. For
example if the
distance between the magnet and the end surfaces of inductor core 110 is
tripled, the
magnetic field strength will be reduced (roughly) by a factor of 27, yielding
diminishing
EMF by-product in the coil accordingly. "GAP" is depicted mainly to denote a
greater
variance in this critical dimension that is controlled by increasing the
magnet grade or
size. Therefore, for an air tool application it can be seen that this method
is far more
versatile over salient pole designs of prior art; in which GAP is constrained
to critical
tolerance of between about 0.005 inches to about 0.020 inches overall. The
opposing
ends of the "I"-shaped inductor core 110 in this case are the "salient" side
pole
CA 02600644 2008-06-12
-16-
arrangements of prior art. Inductor core 110 is therefore curved, or "arced"
as has been
described, to achieve a consistent GAP between end surfaces of inductor core
110 and
the magnet surface 105 as magnets are rotating about the axis of rotation of
rotor 103
along their motion path. The approximate length of an arced I-shaped inductor
is
calculated from a GAP dimension represented by variable "g", a magnet (or
magnetic
field) width variable "w" and a rotor radius variable "r" in an expression %2
pi (r + g) +
(w / 1.25). The lines 41 show the magnetic flux path density during inductive
coupling
tending to curve along "arced" inductor 107, and extending from magnet-to-
magnet. A
magnetic circuit is thereby completed through this inductor "bridge" by the
coincidental
alignment of the opposing inductor 107 ends with respective magnets. Arrows 42
are
shown along a direction of flux flow through the magnetic circuit path, which
magnetic
flux induces electrical current in the copper magnet wire of perpendicular
coil 109.
Arrows 43 about the axis of rotation of rotor 103 show the physical direction
of rotation
of magnets 105 through space during operation along their motion path.
[0039] For a pneumatic tool, stator and rotor magnets comprised of a rotor,
cylinder,
tool housing, magnetic components and inductor of hereinabove described
materials and
related dimensions; the expected current generated by a single stator element
will be
about 250 to about 275 mA (milliAmperes) at a nominal 16,600 revolutions per
minute
(RPM) rotational speed. The current will be delivered at a nominal 5.23 to
about 5.65
VAC (Volts, AC) at a frequency of about 0.553 KHz. Preferably, the rotor speed
for
quick charging of the described capacitor types or thin cell LiPo battery
should be a
conventional about 19,000 to about 21,000 RPM through an initial approximately
10 -
15 seconds. After that, when performing work the tool motor RPM level
typically drops
to about 10,000 to about12,000 RPM for varying periods and may even stall,
such as
when a ratchet wrench is performing a fastening operation. However, after the
initial
charge and through the varying time constants of slower RPM, the charged
capacitor or
cell will continue to deliver relatively uniform DC power to LEDs. At zero
RPM, LEDs
will remain on brightly for up to about 120 seconds for 2 F (Farad) capacitor.
Discharge
times are longer for higher energy density storage devices i.e. lithium ion
cells.
[0040] Figure 7 shows both an elongated working-side view of a pneumatic
ratchet
tool cover 116 and a close up cutaway view of tool cover 116 with embedded
inductive
luminaire 106. Tool cover 116 maybe flexible, comprised of Polyurethane or
EPDM
CA 02600644 2008-06-12
-17-
(ethylene propylene diene monomer) or some other durable nonconductive,
nonabrasive,
shock, chemical, heat resistant and vibration insulating material, such as
modified vinyl,
rubber, silicon or closed cell foam rubber that is easily gripped and can
slide over the
surface of an air tool motor-housing. Tool cover 116 mates with tool housing
115 so as
to position the inductor element 107 on the outside of tool housing 115 such
that it is
properly aligned or magnetically "registered" with magnets 105 retained by
rotor 103
disposed within motor cylinder 119 and tool housing 115. Tool cover 116 also
acts to
provide a protective nonconductive barrier to electronic components from
detrimental
effects in the work environment and to position luminaire 106 such that the
angle of
emissivity of light from the luminaire can be properly directed towards a
workpiece.
Tool cover 116 may be molded around one or both of luminaire 106 and inductor
element 107 thereby to support and position these components properly with
respect to
the magnets 105 and a workpiece. Tool cover 116 therefore includes all of the
normal
and usual recesses and openings to enable a sliding fit over a typical tool
housing with its
conventional mechanical features. The tool cover 116 includes special grooves
on its
internal surface wall that matingly slide over raised lands on the motor
housing, thereby
providing means for anti twisting alignment of cover with the motor housing
and can
accommodate protruding air valve stem, lever roll pin and air inlet, etc. Tool
cover 116
shown in Figure 7 also includes a recessed reflector 126 or LED light
concentrating lens
embedded within a high-density buildup of surrounding protective material to
prevent
damage to LED(s) 114 and reflector 126 or LED light concentrating lens
embedded
therein. A magnetic shield 127 of high magnetic permeability, such as Siemens
VacuPerm 70 hi-permeability Mumetal foil, absorbs stray magnetic field to
thereby
inhibit interference of magnetically sensitive electronic components in the
work
environment.
[00411 Figure 8 shows a pneumatic ratchet wrench having a typical nonferrous
cast
metallic handle enclosed in a plastic protective tool cover 500. According to
an
embodiment the bulk of the unique tool cover 500 is nonconductive material and
further
incorporates discrete copper (conductive) strips, or a dielectric substrate
with etched
copper traces, printed nano-metal silver or copper deposits to form a voltage
plane that is
embedded in an insulator. The dielectric cover with embedded circuits is
thereby an
electrically conductive distributor referred to as a conductive tool cover. A
smaller
CA 02600644 2008-06-12
- 18-
removeably detachable illuminator 510 of likewise construction incorporates
LEDs 114
and interfaces with the conductive tool cover 500 via contact terminals 520.
100421 The embodiment in Figure 8 enables efficient access to a threaded ring
nut
joining the tool handle to the ratchet assembly, particularly during routine
service and
repair of unitized tool constructions. The electronic square area, however,
advantageously spans the end-to-end surface of the cylindrical tool housing
500.
Unitized construction is typical of powered ratchet wrenches and one of the
main
benefits of a conductive tool cover 500 detachable from illuminator 510 is to
electrically
bridge the junction of tools having joined unit construction, which enables
the luminare
closer proximity to the working end of the tool.
[00431 Embedded within the tool handle cover is a stator with at least one
inductor
element 107 and electrically conductive circuit as has been described. Current
generated
in the embedded inductor of conductive tool cover is fed directly through its
external
conductive circuit to LEDs 114 via contact terminals 520 of the circuit.
Advantageously, no other discrete circuit connectors, contact points or other
means of
hardwiring breaching the motor housing of the tool are required for
illumination
applications. Hermetically sealed UO hardwiring passing through the motor
housing
may be utilized if an application requires external stator power to be
supplied to sensors
or special circuits internal to the tool: i.e. torque load-cells embedded
around motor
mounts, magnetostrictive sensors around rotating shafts, event monitors such
as non-
contact vane-wear or lubrication sensors. Optionally, forms of "data"
regarding tool-
operating parameters may be gathered through demodulation of magnetic field
variations
through the tool housing, similar to the reactive coupling used to transmit
and receive
data through well casings in hybrid down-hole well drilling communication
systems. A
second embodiment of unique conductive tool cover 500 facilitates use with
prior art air
motor generators, such as that described in U. S. Patent 7,095,142. To
transfer electricity
to the cover circuit from a prior art "internal generator" (where hermetic
hardwire is
formerly required), embedded conductors on the tool cover 500 simply have open
contact pads exposed on its internal surface (not shown), which are positioned
to align
and connect the circuit via insulated compression terminals affixed to an
insulator base
pressed into the cast metallic tool housing. Circuit connection is made during
assembly,
by action of sliding the tool cover over the motor housing, thereby
compressing
CA 02600644 2008-06-12
-19-
terminals to contact pads. Spring-biased compression terminals commonly used
in cell
phones to make battery terminal connection are one means to accomplish a
sliding
connection. This arrangement enables connection of circuits during typically
normal
phases of tool assembly. The embedded circuit of a luminaire portion of the
tool cover
also has plug like contact terminals 520b within its structure. The contacts
mate with
receptacles on the handle cover when the luminaire is clamped and matingly
locked into
aligning position on the ratchet housing via its semi-rigid and grip-like
structure 510.
[0044] To provide sufficient clamping pressure to the tool body semi-rigid
materials
are preferred for the tool cover and snap-lock features (not shown) at the
joint of the two
tool cover components will further ensure reliable unity between the
conductive tool
cover segments. In addition to conductors, the tool cover may also contain
cavities for
retaining thinly structured moderately fast charging Nickel-Metal Hydride
battery cells
or fast charging thin-cell Lithium Ion (LI) polymer cells, Aerogel ultra-
capacitor as
previously described, or even fuel cells. A preferred conductive tool cover
may embody
a credit card sized area in the form of a recessed cavity wrapped around a
segment of the
cover at an approximate depth of about 0.090 inch, for housing a flexible
battery, such as
previously described extremely fast charge, high power density Organic Radical
Battery
(ORB). The organic radical battery (ORB) is a new class of rechargeable
battery being
uniquely developed by NEC, which is based on cathode and anode structures and
chemistry similar to the commercialized Lithium ion battery except for the use
of earth
friendly organic radical compounds PTMA, or "2,2,6,6-tetramethylpiperidinoxy-4-
yl
methacrylate," with excellent durability. The ORB demonstrates extremely high
power
density and good cycle ability making it suitable for a range of next
generation power
tool applications. A significant difference attributed to the ORB from
conventional
rechargeable batteries commonly found in devices such as notebook computers
and cell
phones, is that instead of using poisonous ingredients like lithium and
cobalt, PTMA is a
nonpoisonous or earth friendly material.
[0045] Figure 9 shows how the separate segments of a two-part conductive tool
cover of Figure 8 align on a segmented tool body of unitized construction
during
assembly. Figure 10 shows the two-part conductive tool cover incorporating
embedded
electronics for illumination, as it would appear during operation.
CA 02600644 2008-06-12
-20-
[0046] Figure 11 shows an embodiment of a conductive tool cover 600 of single-
piece construction, that is adaptable to a tool of joined unit construction as
described
earlier, further comprising both resilient flexible conducting and insulating
materials in
alternate layers. The layers are arranged in three basic groups: group (1) is
formed of
single or plural conductive layers insulated from each other from which
electronic circuit
traces are formed and components connected. The group (1) layer is interposed
as
required in an insulating layer group (2), together that are further
interposed between a
group (3) of bulk insulators that form a final exterior boundary, protecting
the former
layers from the environment. Figure 12 shows segment A-A of a flexible
conductive tool
cover, the structure of which entails the use of highly flexible metalized
elastomeric
conducting material. Material can be a copper (Cu) or silver (Ag) coated
polymer
disposed between insulators to form a conductive bridge between illuminator
and main
circuit of cover 600. Advantageously, this construction enables deployment of
a single-
piece conductive tool cover in combination with two-part unitized air tools,
thereby
eliminating the need for any terminals, connectors and additional parts.
Figure 13 shows
a single-piece conductive tool cover 600 incorporating electronics for
illumination, as it
would appear during operation.
[0047] Because the luminaire portion is inseparable from the main tool body
cover
as opposed to the structure of Figure 8, the embodiment of Figures 11 to 13
requires a
higher degree of flexibility in its embedded conductors and material medium,
especially
in the region of section A-A shown in Figure 12 spanning the tool's adjoined
sections.
One combination that can be used to accomplish conductivity with flexible
structural
integrity is laminated conductive traces etched into metallized polyimidi
(Kapton by
Dupont) to form flexible circuits that can be molded into a urethane matrix to
form the
cover.
[0048] Figure 14 shows a flat, flexible printed circuit (FFC) 300 having white
LEDs
314 for incorporation into a protective flexible tool cover, otherwise known
as a tool
boot, to provide illumination. The FFC 300 further incorporates a plurality of
surface
mount device (SMD) LEDs 304-312 and display driver comprising a transistor-
transistor-logic (TTL) chip 303 or smaller chip-on-board (COB) (not shown) and
operates as an electronic nameplate "insert" for a conductive tool cover. The
term
"insert" as used herein may be understood to mean the component is placed on a
CA 02600644 2008-06-12
-21-
framework to be positioned within a mold prior to an injection of plastic or,
the
component is placed into premolded encasements, sandwiching electronic package
between encasements to be ultrasonically welded together, or adhesively
joined.
Additionally, inserts can be designed to be interchangeable and to facilitate
robotic pick-
and-place injection molding and assembly solutions in mass production
environments.
[0049] The circuit, complete with attached components, can be inserted into
retaining means provided as recessed cavities on the external surface of a
generally
cylindrical pre molded sleeve adhesively applied to an air tool motor housing
and
together with the tool motor housing inserted into a protective cover during
final tool
assembly.
[0050] The FFC printed circuit of Figure 14 is comprised of nonconductive
laminates 301 of polyimidi film enveloping planar conductive traces generally
at 302
having an extremely low profile. Rectified AC current, from, for example,
external
stator inductor element 107, connected through conductive traces 302, is
provided to a
micro display driver integrated circuit (IC). The display driver IC is
comprised of a
control chip, such as a transistor-transistor-logic (TTL), or smaller
ultrafast
complementary metal oxide semiconductor large-scale integration (CMOS LSI)
structure in a chip-on-board (COB) package, such as a GF-2391 (not shown) or a
BCD-
to-Decimal Decoder IC, 7442 shown at 303. A larger image of Figure 14 shows a
typical pin-out on a driver such as the 7442 IC at 303a. Driver IC 303a in
circuit with a
single 1KHz 555 timer IC and one 4-bit asynchronous decade counter IC, 7490 is
capable of sequentially pulse firing up to ten (10) surface-mount high
brightness LED
emitters 304A of different colors. Smaller scale equivalent ICs that use less
power are
available.
[0051] The LEDs 304 - 312 are caused to light whenever the tool is in
operation,
and can be embedded in the tool cover in such a manner to brighten the area of
the
characters of the indicia. Further shown are high brightness white light
LED(s) 314,
such as two (2) of Nichia's NSPW300CS. A preferred embodiment deploys a single
extreme intensity CREE X Lamp XREWHT 7090 (not shown) capable of emitting 100
lumens. LED(s) 314 are energized by the integrated air motor generator through
a
switch (not shown) in the path of conductors of FFC 300, causing operation of
LED(s)
314 independent of LEDs 304 - 312 and the indicia driver chip 303. A low
profile
CA 02600644 2008-06-12
-22-
switch (not shown) in the circuit provides conservation of electrical power,
means to
accomplish faster initial charging of a capacitor or battery cell and faster
initial powering
up of other electronic features or systems on board the tool prior to
switching on lighting
of the work surface during an operation. The LED(s) 314 provide illumination
at a work
surface ahead of the tool. Illumination is desirable to achieve enhanced
visibility in
dimly lit environments and may optionally be switched on automatically by
addition of
dark-detection circuitry.
[00521 The objectives of having electronically enhanced high visibility
markings or
micro displays, that radiate from a locus on the side surfaces of a power tool
can be both
apparent, to draw attention and real, to impart useful information.
Electronically
enhanced power tool indicia can be accomplished through various means. One
method
is to have distinctively visible patterns of sequentially fired LEDs of
alternating colors
embedded in the tool cover. Another method highlights tool bodylines,
lettering or
company logo with neon-like effects utilizing phosphor coated side-emitting
fiber optic
filaments known as electroluminescent (EL) wire. Yet another method that is
more
advanced utilizes recently developed EL technology, such as Dupont Luxprint,
comprised of systems of insulating, conducting and EL ink to create printed
lamps in the
form of letters or art disposed between transparent capacitive substrates
embodied with
the tool. In this disclosure, an electronic "nameplate" is specified and as
such, the lighted
label obviously has the capability of raising the tool users consciousness of
the name
brand or owner of the tool to a higher level. The effect is similar in fashion
to that
achieved by neon colored tool housings introduced into the power tool market
in the
1990s. Power tool body accent lighting effects can be a useful novelty to
attain
commercial interest such as demonstration of private labels at trade show
displays or
celebrated product anniversary releases or can be used for more apparent
display of
private tool users ownership.
[00531 It is conceivable that an electronic micro display can be implemented
as an
electronic "warning" label or as a "reminder" to a tool user, to wear eye
protection. Such
an arrangement would rely on an infrared (IR) transmitter/receiver break-beam-
detection-system coupled to high visibility warning label conspicuously
embodied with
the tool housing or embedded in a conductive cover that slides over the tool.
CA 02600644 2008-06-12
-23-
[0054] The electronic "warning" label power circuit is configured to flash the
illuminating label at a high pulse rate during a "warning" mode, whenever the
air tool is
running. This highly visible, if not visually irritating state of affairs to
the tool operator
persists until the user adorns eyewear safety shielding equipment of which is
optoelectronically "linked" to the tool warning label circuit. The link is
accomplished by
incorporating into the eyewear shield frame, an associated low power
consumption (1.5
- 6V) infrared (IR) forward emitter that flashes at a predetermined pulse
frequency (or
multiple frequencies). The shield emitter is triggered into an "on" state by
means of a
surface-to-surface contact sensor formed as parallel conductive strips
embedded in an
insulating lamination adhesively bonded along the shield mounting head band,
or part
that physically contacts with the operators forehead or skin, such as the
bridge of the
nose whenever protective glasses incorporating the same are worn. Various
types of
conductive sensor materials that can change a circuit resistance when
contacting skin can
be used such as plastics containing high carbon content. The shield based
contact sensor-
switched IR pulsed emitter is optically coupled to an IR receiver on the tool
body that is
configured to respond at a predetermined matching pulse frequency. A receiver
is
conspicuously and unobstructively embodied with the tool or tool cover and
electrically
connected to the warning label. The matched frequency IR receiver controls the
tool's
display driver. Forward IR emission from the eyewear can be from any point on
the
outward facing frontal framework of conventional safety goggles, glasses or
face shield
as long as its IR light pulses can interact through a fairly clear line of
sight with the IR
receiver on board the tool and in front of the operator. Detection of the IR
pulses emitted
from the eye shield by a normally "on" receiver optically triggers a TTL
driver in circuit
with the warning label, into an "off' state for a time constant, similar to a
TV remote
control operation. Thereby, while the eye shield's emitter is switched on
through the
normal wearing by a tool user and facing in the direction of the tool, the
warning mode
of the tool label ceases operation (safe mode) for a time constant. It can be
easily seen
that in order to be effective an operator must be facing the tool (receiver)
while
performing an operation and wearing the electronically enhanced safety shield,
which is
generally a normal state of affairs when operating power tools. This safety
feature is not
intended to be limited only to the specified interaction with a lighted
warning label
indicator, but to the operation of the tool itself by controlling a solenoid
valve.
CA 02600644 2008-06-12
-24-
Disclosure of this safety feature is not intended to be limited to deployment
only on a
pneumatic tool. By disclosure, the author intends that the novel safety
feature be
adapted to control the state of operation of motorized electrical power tools
as well, such
as with heavy electrical powered industrial grinders, in order to attain a
highly enhanced
level of safety and safety awareness with use thereof. Thereby, a "smart tool"
can in fact
assist its operator in the protection of a human eye from the potential
hazards that exist in
the work environment.
[0055] The safety enhancement objective here can also be attained with short
proximity radio frequencies, having an arrangement similar to a PC wireless
features,
having the RF transmitter transceiver, microcontroller and antenna chip, such
as an 868
MHz addLINK115 and contact switch located on the safety shield and RFID
receiver
chip and warning label on the tool. The operation is in similar arrangement to
the above
described optical break-beam-detection system, however a radio version shuts
down the
micro display-warning label (or opens a solenoid valve) while the equipment is
worn,
irrespective of where the user was looking, because it does not depend on line-
of-sight
interaction. It will be understood of course, that any other known method of
data
transmission may be employed.
[0056] Figures 15 and 16 show a conductive tool cover 700 and positioning of
the
FFM 300 of FIGURE 14 with LED enhanced micro display, in cutaway and complete
views.
[0057] Figure 17 shows a pneumatic tool with a conductive tool cover 800
having
embedded electronics for flashing micro display and illumination applied to a
popular
commercial brand of air powered ratchet wrench as it may appear during
operation.
[0058] Figure 18 shows another embodiment of a luminaire 900. In this
embodiment, a Flat Flexible Circuit (FFC) 910 enables the capacitor 920
placement in a
cavity at the back of the tool housing. This embodiment is suitable for a
"cover-over-
housing" approach in which the addition of too many electronic components in
one area
on the external surface of a tool housing creates unacceptable tool
aesthetics. In this
case, FFC 910 enables discrete distribution of components over the housing of
the tool.
[0059] Figure 19 shows safety glasses having embedded electronic radio
frequency
(RF) or infrared (IR) transmitter (transceiver) for communicating with a
remote circuit
on a tool. The remote circuit controls a flashing micro display, configured as
a hazard
CA 02600644 2008-06-12
-25-
warning at a locus on a pneumatic tool conductive cover 800, or controls a
solenoid
valve that can shut down the operation of a pneumatic tool, or switch an
electric tool off
whenever the safety glasses are not worn by the operator.
[0060] The many features and advantages of the invention are apparent from the
detailed specification and, thus, it is intended by the appended claims to
cover all such
features and advantages of the invention that fall within the true spirit and
scope of the
invention. Further, since numerous modifications and changes will readily
occur to
those skilled in the art, it is not desired to limit the invention to the
exact operation
illustrated and described, and accordingly all suitable modifications and
equivalents may
be resorted to, falling within the purpose and scope of the invention.
[0061] For example, while aluminum has been described as the tool housing
material, it will be understood that other nonmagnetic materials, such as
alloys of 300
series stainless steel, magnesium, brass, glass or carbon reinforced plastic
composites or
a combination of composites molded over cast aluminum, magnesium or other
nonmagnetic housing may be employed also.
[0062] While it is advantageous to make use of some of the strongest, most
demagnetizing-resistant magnets commercially available such as NdFeB or SmCo
for
the rotor, it will be understood that the embodiments described herein would
work using
magnets of any magnetic material, albeit at the cost of reduced induced EMF in
stator
coil 109.
[0063] While the above has been described with reference to a pneumatic tool
having a primary function such as a wrench, sander or grinder, it is to be
understood that
the integrated electricity generator disclosed herein may be employed in tools
having
other primary functions. One might also conceive of applications wherein the
primary
function of the tool is to generate electricity for various applications.
[0064] While a press powdered metal rotor body has been described,
alternatives
such as a combination of machined PPM rotor body, molded carbon fiber and
plastic
composite or molded plastic rotor body may be considered for certain
applications.
[0065] The above-described contributions enable users of pneumatic tools to
benefit
from advancements in precision and accuracy in power tool related functions,
limited
only by high accuracies attainable through the electronic arts and more
specifically to
functions employing: micro controller chips and displays, memory, computers
and
CA 02600644 2008-06-12
-26-
digital readouts for fastener torque calculation and monitoring, impact force
measurement, automatic lubricators and lubrication reminders, vibration
monitoring to
alleviate conditions leading to tendonitis, operation cycle counting, location
announcing,
IR and RF input-output communication devices, visual imaging, theft deterrent,
drop
monitoring, identification, safety awareness, warranty metering, Internet Wi-
Fi
operations, light show displays and/or work surface illumination etc.
[0066] Although embodiments of the invention have been described, those of
skill
in the art will appreciate that variations and modifications may be made
without
departing from the spirit and scope thereof as defined by the appended claims.
