US3407885A - Air balance for impact wrenches - Google Patents

Air balance for impact wrenches Download PDF

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Publication number
US3407885A
US3407885A US622209A US62220967A US3407885A US 3407885 A US3407885 A US 3407885A US 622209 A US622209 A US 622209A US 62220967 A US62220967 A US 62220967A US 3407885 A US3407885 A US 3407885A
Authority
US
United States
Prior art keywords
housing
tool
motor
cavity
fluid
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US622209A
Other languages
English (en)
Inventor
Martin D Hoza
Robert A Pennison
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
REED INTERNATIONAL Inc
Original Assignee
REED INTERNATIONAL Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by REED INTERNATIONAL Inc filed Critical REED INTERNATIONAL Inc
Priority to US622209A priority Critical patent/US3407885A/en
Priority to GB6502/68A priority patent/GB1198773A/en
Priority to SE2543/68A priority patent/SE342165B/xx
Priority to FR1555262D priority patent/FR1555262A/fr
Priority to NL6802957.A priority patent/NL163450C/xx
Priority to DE1678397A priority patent/DE1678397C3/de
Application granted granted Critical
Publication of US3407885A publication Critical patent/US3407885A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
    • B25B—TOOLS OR BENCH DEVICES NOT OTHERWISE PROVIDED FOR, FOR FASTENING, CONNECTING, DISENGAGING OR HOLDING
    • B25B21/00—Portable power-driven screw or nut setting or loosening tools; Attachments for drilling apparatus serving the same purpose
    • B25B21/02—Portable power-driven screw or nut setting or loosening tools; Attachments for drilling apparatus serving the same purpose with means for imparting impact to screwdriver blade or nut socket
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N13/00—Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00
    • F01N13/001—Gas flow channels or gas chambers being at least partly formed in the structural parts of the engine or machine

Definitions

  • a rotary impact tool is disclosed by the hereinafter specification.
  • the tool housing is provided with forward and rear cavities which are connected by channel for equalizing fluid pressure therebet-ween.
  • the said tool is provided with atmospheric vents operatively connected to said cavities.
  • This invention relates generally to a fluid operated rotary impact tool which initially runs down nuts, bolts, screws or the like and as resistance to such an operation, develops to impart blows to said nuts, bolts, screws and the like to effect a final tightening of same.
  • Rotary impact tools of the general type contemplated by this invention are powered by pressurized fluid operated motors.
  • fluid is supplied to a motor cylinder and is used to apply pressure to rotor vanes for the purpose of turning a rotor shaft.
  • the volume of fluid is usually different in each of the portions, and therefore, a pressure differential usually exists between the said portions of the housing. Certain undersirable effects may be directly attributed to the stated pressure differential.
  • lubricants are driven by the pressure differential and as a consequence some internal areas of the tool are lubricant starved whereas other areas are lubricant rich.
  • the said pressure differential may even be sufficient to cause lubricants to be blown out of the tool housing.
  • the force created by the pressure differential also affects the operation of the tool in that it operates as a retarding or staying force against either the thrust or return of the tool hammer depending on the region of high pressure. And, if the high pressure area is in the forward portion of the tool then a thrust is exerted on the tool anvil thereby creating a drag that reduces the effective output power of thetool.
  • FIGURE 1 is a side sectional view of the preferred ice:
  • an elastic pressure fluid operated impact tool comprising a housing 10 enclosing a rotary vane-type motor 12.
  • the motor is provided with a rotor 14 extending between a front bearing plate 16 and a rear bearing plate: 18.
  • the rotor 14 is provided with shaft ends mounted respectively for rotation in a forward bearing assembly 20 and a rear bearing assembly 22.
  • the rear bearing plate 18 is an annular shaped member having a bore 24 and a counterbore 25 and is positioned in abutting engagement with the motor 12.
  • the rear shaft end of the rotor 14 is positioned within the bore 24 of the plate 18 while the rear bearing assembly 22 is supported on said rear shaft end within the counterbore 25.
  • the rotor is provided with an inwardly projecting shoulder 26, adjacent the said shaft end, against which is disposed a roller bearing assembly 27 and a compression spring 28.
  • the compression spring extends between the said roller bearing assembly and a Spring cup 30. earl
  • the bearing plate 18, for reasons that will appear, is fixed in position relative to the housing 10 by being secured to an end Wall 34 by a pin 40, and to the motor 12 by a pin 41.
  • the structure of the tool as thus described defines a rear cavity 42 in the counterbore 25 between the bearing assembly 22 and the end wall 34.
  • a similar area generally exists to some extent in all rotary impact tools, and motor fluid tends to leak into this area notwithstanding the best of seals for preventing such leakage. Generally speaking, this fiuid leaks into the space through the junction of the rear bearing plate 18 and the rotor 14.
  • the leakage space or area has been emphasized or enlarged to define the motor leakage fluid cavity 42 as a collecting chamber for said fluid.
  • the rotor 14 is provided wit-h a central bore 46, a portion of which is splined for the purpose of securing a rotatable hammer 48 therein.
  • the hammer 48 is provided at its forward end with a plurality of lugs '50 which coact with lugs 52 on a rotatably driven anvil 54.
  • the anvil 54 is mounted in a bushing 55 in the forward portion of the housing 10 and is arranged to extend from the housing in the usual manner and is provided with driving flats 56.
  • the anvil is driven by an elongated shaft 58 that extends through the hammer 48 in spaced relation there with and terminates in an enlarged portion which extends into and is pinned to the anvil.
  • the rear end portion of the drive shaft 58 is fixed in a cam assembly of the general type as disclosed and described in the US. patent to Martin D. Hoza No. 3,156,334.
  • the rear end of the shaft 58 is reduced in diameter to provide flats in the cam assembly end, and said end of the shaft extends generally to the aperture 38 in the spring cup 30 in order that lubricants may be introduced therein for the purpose of lubricating the moving and contacting surfaces of the tool.
  • the housing 10 is bored or otherwise provided with an annular chamber or cavity 62 in the vicinity of the lugs 50 and 52.
  • This cavity defines a forward fluid pocket or chamber for receiving or collecting leakage fluid from the forward end of the motor 12.
  • the said operating fluid in practice leaks out between a forward shaft end 64 of the rotor 14 and the front bearing plate 16.
  • cavities similar to the cavities 42 and 62 exist to some extent 3 whether due to design or not. It is because of their existence and because of the fact that the operating fluid for the air motor leaks or bleeds into these cavities that a pressure differential is created internally of the tool between the two said cavities.
  • the two cavities are structurally incorporated into the tool design as stated.
  • the housing 10 is provided with a longitudinally extending channel 66 for connecting the two said cavities.
  • the channel 66 communicates directly with the front cavity 62 and extends generally in a straight line longitudinally across the top of housing 10 to the rear bearing plate 18.
  • the rear bearing plate is formed with a port 68, which registers with the cavity 42 and provides communication with the channel 66.
  • the two cavities 42 and 62 being in direct communication with each other will thus allow fluids leaking into them to commingle through the channel 66 and thereby equalize pressure throughout the housing thus eliminating the internal pressure differential between the forward and rear portions of the tool.
  • the described exhaust system also eliminates the difference in pressure between the cavities 42 and 62 by effectively placing them at atmosphric pressure.
  • the pressure thus maintained in the forward cavity and therefore, the forward end of the tool is relatively low. Accordingly, the anvil 54 is not subjected to a forward thrust as is the usual case in such tools so that the effective output power of the tool is increased.
  • the aforedescribed undesirable feature of lubricant blowout is effectively eliminated.
  • a rotary impact tool comprising a housing, an electric pressure fluid operated motor supported within said housing, a hammer rotatably carried by and slidable within said motor, means within said motor to cause said motor to rotate said hammer, said housing having a cavity in the forward portion thereof, a rotatable anvil mounted in the cavity in the forward portion of said housing, means supported in said housing contiguous to the rear of the housing and defining therewith a cavity in the rear portion of the housing, said housing having a channel formed therein communicating with the forward cavity and terminating adjacent the rear of said housing, said means having a passage therein providing communication with said rear cavity and channel to equalize the pressure between the forward and rear portions of said housing and maintain a balanced pressure condition upon the forward and rearward ends of said hammer.
  • said last-mentioned means constitutes a bearing plate for supporting an end of said motor, said plate having a counterbore formed therein which defines with the end of said housing the cavity in the rear portion of the housing.
  • An impact tool according to claim 1 wherein said housing is provided with a fluid collection chamber, a vent connecting said chamber to the atmosphere, a first port connecting said forward cavity to said chamber, and a second port connecting said second cavity to said chamber.
  • An impact tool comprising a housing, an elastic pressure fluid operated motor, the said housing having fluid passageways communicating with said motor, a rotatable hammer having an enlarged end and a reduced end, the said reduced end being coaxial with and telescoped within said motor, the said enlarged end of said hammer having one or more driving jaws, said housing having a cavity in the forward end and a cavity in the rear end, a rotatable anvil mounted in the forward cavity of said housing, said anvil having one or more driven jaws confronting in said forward cavity with said driven jaws, and elongated passageway formed in said housing and communicating with said cavities to maintain a balanced pressure condition upon said anvil and said enlarged end of said hammer whereby there will be a natural migration of lubricant to all parts of the tool throughout the housing.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • General Engineering & Computer Science (AREA)
  • Details Of Spanners, Wrenches, And Screw Drivers And Accessories (AREA)
  • Percussive Tools And Related Accessories (AREA)
US622209A 1967-03-10 1967-03-10 Air balance for impact wrenches Expired - Lifetime US3407885A (en)

Priority Applications (6)

Application Number Priority Date Filing Date Title
US622209A US3407885A (en) 1967-03-10 1967-03-10 Air balance for impact wrenches
GB6502/68A GB1198773A (en) 1967-03-10 1968-02-09 Improvements in Impact Tools
SE2543/68A SE342165B (xx) 1967-03-10 1968-02-28
FR1555262D FR1555262A (xx) 1967-03-10 1968-02-29
NL6802957.A NL163450C (nl) 1967-03-10 1968-03-01 Rotatieslagwerktuig.
DE1678397A DE1678397C3 (de) 1967-03-10 1968-03-06 Schlagschrauber

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US622209A US3407885A (en) 1967-03-10 1967-03-10 Air balance for impact wrenches

Publications (1)

Publication Number Publication Date
US3407885A true US3407885A (en) 1968-10-29

Family

ID=24493321

Family Applications (1)

Application Number Title Priority Date Filing Date
US622209A Expired - Lifetime US3407885A (en) 1967-03-10 1967-03-10 Air balance for impact wrenches

Country Status (6)

Country Link
US (1) US3407885A (xx)
DE (1) DE1678397C3 (xx)
FR (1) FR1555262A (xx)
GB (1) GB1198773A (xx)
NL (1) NL163450C (xx)
SE (1) SE342165B (xx)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20060067800A1 (en) * 2004-09-30 2006-03-30 Ati Industrial Automation, Inc. Force-balanced air supply for pneumatic tools
US20060201689A1 (en) * 2005-03-10 2006-09-14 Sears Brands, L.L.C. Tool having a protected switch
US9289886B2 (en) 2010-11-04 2016-03-22 Milwaukee Electric Tool Corporation Impact tool with adjustable clutch

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3823795A (en) * 1973-05-30 1974-07-16 Black & Decker Mfg Co Air tool muffler

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2476632A (en) * 1947-05-20 1949-07-19 Keller Tool Co Rotary impact tool
US3156334A (en) * 1961-05-16 1964-11-10 Reed Roller Bit Co Impact tool with hammer rotatable and axially movable within the motor
US3169585A (en) * 1961-01-11 1965-02-16 Spencer B Maurer Power operated rotary impact tool
US3175660A (en) * 1962-09-28 1965-03-30 Skil Corp Rotary impact tool
US3212590A (en) * 1963-07-29 1965-10-19 Reed Roller Bit Co Impact wrench
US3253662A (en) * 1961-10-20 1966-05-31 Cooper Bessemer Corp Controlled torque tool

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2476632A (en) * 1947-05-20 1949-07-19 Keller Tool Co Rotary impact tool
US3169585A (en) * 1961-01-11 1965-02-16 Spencer B Maurer Power operated rotary impact tool
US3156334A (en) * 1961-05-16 1964-11-10 Reed Roller Bit Co Impact tool with hammer rotatable and axially movable within the motor
US3253662A (en) * 1961-10-20 1966-05-31 Cooper Bessemer Corp Controlled torque tool
US3175660A (en) * 1962-09-28 1965-03-30 Skil Corp Rotary impact tool
US3212590A (en) * 1963-07-29 1965-10-19 Reed Roller Bit Co Impact wrench

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20060067800A1 (en) * 2004-09-30 2006-03-30 Ati Industrial Automation, Inc. Force-balanced air supply for pneumatic tools
US7396197B2 (en) * 2004-09-30 2008-07-08 Ati Industrial Automation, Inc. Force-balanced air supply for pneumatic tools
US20060201689A1 (en) * 2005-03-10 2006-09-14 Sears Brands, L.L.C. Tool having a protected switch
US9289886B2 (en) 2010-11-04 2016-03-22 Milwaukee Electric Tool Corporation Impact tool with adjustable clutch

Also Published As

Publication number Publication date
SE342165B (xx) 1972-01-31
GB1198773A (en) 1970-07-15
DE1678397A1 (de) 1971-11-11
NL163450C (nl) 1980-09-15
FR1555262A (xx) 1969-01-24
NL6802957A (xx) 1968-09-11
NL163450B (nl) 1980-04-15
DE1678397B2 (de) 1977-08-04
DE1678397C3 (de) 1978-03-30

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