US3579037A — Portable tool

Claim 1

Independent Claim 176 words

In combination, a portable electric tool for use underwater by a human operator, and an electrical control circuit for actuating said tool, said combination providing minimal danger of harmful electrical shock to said human operator, said tool comprising a housing, an electrical drive motor having a stator and a rotor, and an output shaft, said stator being fixedly mounted within sad housing, said rotor being operatively connected to said output shaft, said housing having passages therein to permit the flow of water between said stator and rotor, said electrical control circuit being operatively connected to windings of said stator so as to supply electrical current to said windings, said control circuit including a current leakage responsive trip circuit operative to cut off current to said stator in the event of a leakage current of a magnitude potentially harmful to said human operator when underwater, said trip circuit having a response time less than the cycle time required for current to build to a level harmful to said human operator in the event of said current leakage.

Claim 2

Dependent Claim 176 words

In combination, a portable electric tool for use underwater by a human operator, and an electrical control circuit for actuating said tool, said combination providing minimal danger of harmful electrical shock to said human operator, said tool comprising a housing, an electrical drive motor having a stator and a rotor, and an output shaft, said stator being fixedly mounted within sad housing, said rotor being operatively connected to said output shaft, said housing having passages therein to permit the flow of water between said stator and rotor, said electrical control circuit being operatively connected to windings of said stator so as to supply electrical current to said windings, said control circuit including a current leakage responsive trip circuit operative to cut off current to said stator in the event of a leakage current of a magnitude potentially harmful to said human operator when underwater, said trip circuit having a response time less than the cycle time required for current to build to a level harmful to said human operator in the event of said current leakage.

Claim 3

Dependent Claim 33 words

The combination of claim 1 wherein said trip circuit is responsive in less than 30 milliseconds to cut off current flow completely in the event of current leakage as small as 5 milliamps.

Claim 4

Dependent Claim 18 words

The combination of claim 1 wherein said trip circuit includes a differential transformer to detect said current leakage.

Claim 5

Dependent Claim 76 words

The combination of claim 1 wherein said trip circuit comprises a differential transformer connected in series with windings of said stator, said transformer being operative to control a relay, said relay having contacts in the circuit to said stator windings, said contacts being so connected to said control circuit that a current leakage through said portable tool is operative to deenergize said relay, open said relay contacts, and cut off all current to said portable tool.

Claim 6

Dependent Claim 186 words

In combination, a portable electric tool for Use underwater by a human operator and an electrical control circuit for actuating said tool, said combination providing minimal danger of harmful electrical shock to said human operator, said tool comprising a tool housing having an electric motor mounted therein, said motor comprising, a stator and a rotor, said stator being fixedly mounted within said housing and electrically insulated therefrom, said rotor being supported by said housing for rotation within said stator, said rotor being operatively connected to an output shaft, said housing having passages therein to permit the flow of water between said stator and rotor, said electrical control circuit being operatively connected through an on-off control switch to windings of said stator so as to supply electrical current to said windings through at least two electrical leads, said switch being mounted within said tool housing, said control circuit including a current leakage responsive trip circuit operative to cut off current to said tool in less time than 30 milliseconds in the event of a ground current leak of as little as 5 milliamps in said portable tool.

Claim 7

Dependent Claim 186 words

In combination, a portable electric tool for Use underwater by a human operator and an electrical control circuit for actuating said tool, said combination providing minimal danger of harmful electrical shock to said human operator, said tool comprising a tool housing having an electric motor mounted therein, said motor comprising, a stator and a rotor, said stator being fixedly mounted within said housing and electrically insulated therefrom, said rotor being supported by said housing for rotation within said stator, said rotor being operatively connected to an output shaft, said housing having passages therein to permit the flow of water between said stator and rotor, said electrical control circuit being operatively connected through an on-off control switch to windings of said stator so as to supply electrical current to said windings through at least two electrical leads, said switch being mounted within said tool housing, said control circuit including a current leakage responsive trip circuit operative to cut off current to said tool in less time than 30 milliseconds in the event of a ground current leak of as little as 5 milliamps in said portable tool.

Claim 8

Dependent Claim 33 words

The combination of claim 5 wherein said tool housing is made from anodized aluminum and said output shaft is made from stainless steel, said shaft and said housing being separated by nonmetallic bearings.

Claim 9

Dependent Claim 35 words

The combination of claim 5 wherein said switch is mounted within a switch housing, said switch housing being filled with liquid so as to preclude high underwater pressures from affecting the operation of said switch.

Claim 10

Dependent Claim 37 words

The combination of claim 5 which further includes a third lead connected at one end to said tool housing and at the other end to ground near the source of power supply to said two electrical leads.

Claim 11

Dependent Claim 54 words

The combination of claim 5 wherein said two electrical leads are surrounded by a dielectric material, said dielectric material covered leads being surrounded by a metal sheath which is connected at one end to said tool housing and at the opposite end to a ground near the source of power supply to said lead.

Claim 12

Dependent Claim 16 words

The combination of claim 9 wherein said metal sheath is surrounded by a dielectric material sheath.

Claim 13

Dependent Claim 25 words

The combination of claim 10 wherein the dielectric material surrounding said electrical leads is polyethylene and the dielectric material surrounding said metal sheath is polyurethane.

Claim 14

Dependent Claim 193 words

In combination, a portable electric tool for use underwater by a human operator and an electrical control circuit for actuating said tool, said combination providing minimal danger of electrical shock to said human operator, said tool comprising an anodized aluminum housing having an electric motor mounted therein, said motor comprising a stator and a rotor operative to drive an output shaft, said stator being fixedly mounted within said housing and electrically insulated therefrom by a resinous potting material completely encasing the windings of said stator, said rotor being rotatably mounted within said stator, said rotor including a rotor shaft supported for rotation within said housing, said housing having passages therein to permit the flow of water between said stator and rotor, said electrical control circuit including a pair of electrical leads connected through an on-off switch to windings of said stator so as to supply electrical current to said windings, said switch being mounted within said housing, said electrical leads being surrounded by a sheath of dielectric material, said dielectric material surrounded leads being encased in a flexible metal sheath, and said flexible metal sheath being encased in a sleeve of dielectric material.

Claim 15

Dependent Claim 193 words

In combination, a portable electric tool for use underwater by a human operator and an electrical control circuit for actuating said tool, said combination providing minimal danger of electrical shock to said human operator, said tool comprising an anodized aluminum housing having an electric motor mounted therein, said motor comprising a stator and a rotor operative to drive an output shaft, said stator being fixedly mounted within said housing and electrically insulated therefrom by a resinous potting material completely encasing the windings of said stator, said rotor being rotatably mounted within said stator, said rotor including a rotor shaft supported for rotation within said housing, said housing having passages therein to permit the flow of water between said stator and rotor, said electrical control circuit including a pair of electrical leads connected through an on-off switch to windings of said stator so as to supply electrical current to said windings, said switch being mounted within said housing, said electrical leads being surrounded by a sheath of dielectric material, said dielectric material surrounded leads being encased in a flexible metal sheath, and said flexible metal sheath being encased in a sleeve of dielectric material.

Claim 16

Dependent Claim 34 words

The combination of claim 12 wherein said flexible metal sheath is connected at one end to said housing and is grounded at the opposite end near the source of electrical current to said lead.

Claim 17

Dependent Claim 14 words

The combination of claim 12 wherein said rotor shaft is made from stainless steel.

Claim 18

Dependent Claim 13 words

The combination of claim 12 wherein said shaft is supported by nonmetallic bearings.

Claim 19

Dependent Claim 41 words

The combination of claim 12 wherein said on-off switch is mounted within a sealed switch housing, said switch housing being filled with liquid so as to enable said switch to operate in environmental pressures up to 500 pounds per square inch.

Claim 20

Dependent Claim 49 words

The combination of claim 12 wherein all of the components of said tool other than the bearings are made from anodized aluminum or stainless steel, and the metal components made from different materials are only placed in contacting relationship over very small areas so as to minimize galvanic corrosion.

Claim 21

Dependent Claim 52 words

The combination of claim 12 which includes a third electrical lead mounted within said flexible metal sheath, said third electrical lead being electrically connected at one end to said tool housing and being electrically connected at the other end to ground near the source of power supplied to said two electrical leads.

Claim 22

Dependent Claim 46 words

The combination of claim 18 which further includes a current leakage trip circuit operative to cut off all current flow to said tool in less than 30 milliseconds in the event of a ground current leak of as little as 5 milliamps in said portable tool.

Claim 23

Dependent Claim 26 words

The combination of claim 19 wherein said current leakage responsive trip circuit includes a differential current transformer operable to detect current leakage in the control circuit.

Claim 24

Dependent Claim 90 words

The combination of claim 12 wherein said housing comprising a handle grip, a switch enclosure, a pair of end caps and a motor-enclosing sleeve, said stator is located within said housing sleeve and between said pair of end caps, said stator including current-carrying electrical windings, said windings being encased in a resinous potting material and thereby separated and electrically insulated from said sleeve and end caps, and said rotor is supported upon a stainless steel rotor shaft, said rotor shaft being supported for rotation upon nonmetallic bearings within said housing.

Claim 25

Dependent Claim 12 words

The combination of claim 21 wherein said bearings are made from graphite.

Claim 26

Dependent Claim 38 words

The combination of claim 21 wherein said switch is enclosed within a sealed switch housing, said sealed switch housing being filled with liquid so that said switch is insensitive to pressures up to 500 pounds per square inch.

Claim 27

Dependent Claim 67 words

The combination of claim 21 which further includes a gear reduction unit mounted upon one end of said housing and secured to one of said end caps, said gear reduction unit comprising an input gear operative to drive at least one output shaft through a series of gears, said output shaft and said rotor shaft being made from stainless steel and supported for rotation within nonmetallic bearings.

Claim 28

Dependent Claim 23 words

The combination of claim 24 wherein at least one of the gears located within said gear reduction unit is made from acetal plastic.

Claim 29

Dependent Claim 18 words

The combination of claim 21 wherein a stainless steel sleeve is secured to the interior of said stator.

Claim 30

Dependent Claim 21 words

The combination of claim 26 wherein water flow passages are provided to enable water to flow between said rotor and stator.

Claim 31

Dependent Claim 16 words

The combination of claim 27 wherein said motor is a capacitor start type of induction motor.

Claim 32

Dependent Claim 51 words

The combination of claim 21 wherein said stator is surrounded by a thin-walled aluminum sleeve, said sleeve having sufficient rigidity and strength to support said stator, the rigidity of said tool between said end caps being provided by said electrical motor and primarily by said resinous potting material surrounding said stator.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1974-05-17	1974-11-16	1975-05-18	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1978-05-17	1978-11-16	1979-05-18	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1982-05-17	1982-11-16	1983-05-18	$7700.00	Window Closed / Lapsed

Portable tool

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