US3724560A - Automatic throttle shut-off power tool - Google Patents

Automatic throttle shut-off power tool Download PDF

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Publication number
US3724560A
US3724560A US00178553A US3724560DA US3724560A US 3724560 A US3724560 A US 3724560A US 00178553 A US00178553 A US 00178553A US 3724560D A US3724560D A US 3724560DA US 3724560 A US3724560 A US 3724560A
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US
United States
Prior art keywords
valve
motor
passage
movable
plug
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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
US00178553A
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English (en)
Inventor
D Tibbott
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.)
Ingersoll Rand Co
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Ingersoll Rand Co
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Filing date
Publication date
Application filed by Ingersoll Rand Co filed Critical Ingersoll Rand Co
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Publication of US3724560A publication Critical patent/US3724560A/en
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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
    • B25B23/00—Details of, or accessories for, spanners, wrenches, screwdrivers
    • B25B23/14—Arrangement of torque limiters or torque indicators in wrenches or screwdrivers
    • B25B23/145—Arrangement of torque limiters or torque indicators in wrenches or screwdrivers specially adapted for fluid operated wrenches or screwdrivers

Definitions

  • ABSTRACT v A fluid-operated rotary power tool having "a motor supply valve which is moved into engagement with a movable valve sleeve in response to a clutch reachinga predetermined torque load, thereby closing the valve and stopping the motor.
  • the movable valve sleeve is 10 Claims, 7 Drawing Figures BACKGROUND OF THE INVENTION
  • This invention relates to the art of power-operated tools such as power screwdrivers and wrenches and more particularly to a power tool that automatically stops in response to a selected torque load.
  • My U.S. Pat. No. 3,512,590 discloses a power screwdriver having a valve that opens to start the tool motor upon moving rearwardly over a first increment of travel and closes to stop the motor upon continuing to move rearwardly through an additional increment of travel, the additional valve travel being caused by the tool reaching a selected torque load on its spindle.
  • the mechanism causing the valve to close when moving rearwardly includes a latch that releases a movable valve seat that is urged toward the valve.
  • the principal object of this invention is to provide a valve mechanism that is an improvement over that in the above named U.S. patent and one that eliminates the valve latch mechanism disclosed in said patent.
  • the above objects are attained by providing a valve ball or plug that moves rearwardly off a fixed valve seat, to initially start the tool motor, by posi- I tioning a movable annular valve seat between the valve plug and the fluid pressure source, providing a spring means urging the movable valve seat away from the valve plug and arranging the movable valve seat so that when it engages the valve plug, a differential pressure is created acting to urge and hold it against the valve plug, thereby closing the fluid passage to the motor, while the valve plug returns to its normally closed posi tion engaging its fixed seat.
  • FIG. 2 is a section taken on line 2-2 in FIG. 1;
  • FIGS. 3 to 5 are fragmentary view of the valve of FIG. 1 shown in various positions;
  • FIGS. 6 and 7 are fragmentary sectional views similar to FIGS. 3 to 5 and showing a second embodiment of the valve.
  • the power-operated screwdriver 1 shown in FIG. 1 includes a casing 2 housing an air motor 3 having a screw finder 7 and a screwdriving blade 8 adapted to engage the slot of a screw.
  • the blade 8 is detachably mounted in a spindle 9 which is rotatably and slidably mounted in a journal bearing 10 integrally formed in the interior of the casing.
  • the bearing 10 carries a rearwardly facing shoulder 11 which engages a portion of the spindle 9 to limit its forward movement.
  • the motor drive shaft 4 is mounted in the bearing 12. All of the foregoing structure is conventional in the screwdriver art.
  • the spindle 9 is interconnected to the motor drive shaft 4 by a torque responsive clutch mechanism 14 which releases under a predetermined torque load.
  • the clutch mechanism 14 includes a hollow clutch shaft 15 having its rear end slidably splined in a socket 16 formed in the motor drive shaft 4, thus allowing the clutch shaft 15 to slide rearwardly into the socket 16 for a limited distance while maintaining a continuous driving connection therebetween.
  • the front end of the clutch shaft 15 is attached to the spindle 9 by a connection which allows the clutch shaft 15 to rotate relative thereto while being unable to slide axially relative to the spindle 9.
  • This connection is formed by the front end of the clutch shaft 15 being seated in a rearwardly-opening bore 17 provided in the spindle 9 with several balls 18 being located in mating annular grooves formed in the clutch shaft 15 and the interior wall of the bore 17.
  • the clutch shaft 15 is urged forwardly by a light spring 20 engaged between the bearing 12 mounting the drive shaft 4 and a washer 22 resting on a rearwardly facing shoulder formed on the clutch shaft 15.
  • the light spring 20 biases the spindle 9 against the shoulder 11 of the bearing 10.
  • the clutch shaft 15 and spindle 9 are moved rearwardly in the tool by an operator forcing the tool blade 8 downwardly against a screw.
  • the depth of the socket 16 in the drive shaft 14 limits the rearward movement of the clutch shaft 15. r
  • the clutch shaft 15 carriers an integral clutch plate 24 which contains a series of holes spaced around its center. These holes house corresponding clutch balls 25 adapted to seat in mating ball seats or recesses provided in the rear face of the spindle 9.
  • the balls 25 are pressed into their seats in the spindle 9 by a pressure ring 26 which is urged forward by a clutch spring 27.
  • the rear end of the clutch spring 27 seats against a collar 28 keyed on the clutch shaft 15 .and is held in place by a nut 29 threaded on the clutch shaft 15.
  • a detent ball 30 is located in the rear face of the collar for seating in any of a series of cavities in the front face of the nut 29 to latch the nut 29 in its adjusted position.
  • the nut 29 includes gear teeth 31 on its periphery for engaging with a jacobs chuck key (not shown) to enable turning the nut 29 for adjusting the load on the clutch spring 27
  • the load on the clutch spring 27 will determine the magnitude of torque: load at which the torque clutch 14 releases.
  • the presser ring 26 engages a cross bar 32 which slides in a diametrical slot 33 formed in the clutch shaft 15 and abuts the forward end of a push-rod 34 extendis engaged by the rear end of the push-rod 34 and closes the rear end of a valve passage 39.
  • the valve passage 39 is connected to a motor supply passage 40 extending to the tool motor 3.
  • the valve 37 controls the flow of air from the valve chamber 36 to the motor 3 via the passage 39 and the motor supply passage 40.
  • the strength of the spring 43 is weak enough to be easily overcome by this pressure differential.
  • the interior of the valve sleeve 42 is smaller than the valve ball 37 whereby it is plugged by the valve ball 37.
  • the inner edge of the forward end of the sleeve 42 can beveled as shown in FIG. 3 to form a better seal when engaged bythe valve ball 37.
  • the valve sleeve 42 includes an inwardly directed flange 44 at its rear end to serve as an abutment for the spring 43.
  • the rear end of the axial bore 35 is formed as a shoulder 45 and a resilient member such as the be]- leville spring 46 is located between the shoulder 45 and the sleeve 42 to allow the sleeve 42 freedom to move rearward for a slight distance during the initial engagement of the valve ball 37 with the sleeve 42.
  • the belleville spring 46 serves as a bumper or buffer for the valve sleeve 42 and also enables it to move rearwardly in case the rearward movement of the valve ball 37 is greater than the movement required merely for it to engage the valve sleeve 42.
  • valve ball 37 engages the valve sleeve 42
  • the pressure differential causes them to remain engaged until the valve ball 37 is returned to its fixed seat 38, as shown in FIG. 5.
  • the operator lifts the screwdriver from the screw, allowing the spindle 9 to move forward to seat on the bearing shoulder 11. This movement allows the push-rod 34 and valve 37 to move forward until the valve 37 is again seated on the fixed or stationary valve seat 38.
  • the valve sleeve 42 remains engaged with the valve ball 37 to continue to close the flow of air to the tool motor.
  • the pressure differential across the valve sleeve 42 is rapidly eliminated by a slight leakage across the sleeve 42 which is provided by the design of the tool. For example, this slight leakage can take place between the bore 35 and the sleeve 42 or it can be provided by the engaging surfaces between the valve ball 37 and the sleeve 42.
  • the spring 43 returns the valve sleeve 42 rearwardly to the position shown in FIG. 1 and the tool is ready for another cycle.
  • FIGS. 6 and 7 replaces the valve sleeve 42 of the first embodiment with a valve sleeve 50 having an interior that snugly receives the valve ball 37 as shown in FIG. 7 to shut-off the flow of air to the motor.
  • the interior of the sleeve 50 can be provided with a resilient coating to aid in sealing between the sleeve 50 and the valve ball 37.
  • a fluid-operated rotary power tool comprising a casing
  • valve plug movable along said passage between a first position where it is closed to a second position, said plug being shaped whereby fluid flowing in said passage is free to flow past said valve plug to said motor when said plug is located intermediate said positions;
  • a movable annular valve seat located in said passage between said valve plug and the motive fluid pressure source and slidable along said passage between travel limits where it can be engaged with said valve plug in both said first and second positions and being normallylocated where it will be engaged by said valve plug in said second position,
  • said movable valve seat being operative to close said passage when engaged with said valve plug to prevent the flow of fluid therethrough;
  • said movable annular valve seat having a surface that is acted on by the fluid pressure of said motive fluid when engaged with said valve plug and is operative to hold the movable valve seat against said valve plug during the movement of said valve plug from said second position to said first position.
  • a second annular valve seat located in said passage between said valve plug and motor and located to engage said valve plug in said first position to close said passage.
  • the power tool of claim 2 including:
  • torque sensing means connected to said motor to measure the torque on said motor and being operative, in response to a predetermined torque load on said motor, to effect the movement of said valve plug to its engagement position with said movable valve seat.
  • said torque sensing means is a torque-responsive clutch connected to a rod extending towards said valve plug and operative to move, said plug toward said movable valve seat when said clutch reaches said predetermined torque.
  • a fluidoperated rotary power tool comprising:
  • a housing including a fluid-operated rotary motor
  • valve in a passage controlling the flow of motive fluid from a fluid pressure source to said motor and movable in a single direction in said housing over a distance including first and second successive increments of travel, said valve being movable over said first increment of travel from a normally closed position to an open position and movable over said second increment of travel from said open position;
  • torque sensing means connected to said motor to measure the torque on said motor and being operative, in response to the rise of the torque load to a predetermined torque load, to move said valve over said second increment of its travel;
  • valve seat located in said passage between said valve and the fluid pressure source where it can be engaged with said valve at the end of the second increment of its travel, said valve seat being operative to close said passage when engaged with said valve to prevent the flow of motive fluid therethrough;
  • said movable valve seat being slidable in said passage and having a surface that is acted on by said high fluid pressure when engaged with said valve that is operative to hold the valve seat against said valye during the return movement of said valve to its normally closed position.
  • a second valve seat located in said passage between said valve and motor and located to engage said valve in said normally closed position.
  • said movable valve seat is an annular sleeve having a bore therethrough and slidable axially along said passage toward and away from said valve;
  • saidvalve plugs the end of the bore of said sleeve when engaged thereto.
  • said spring means is a spring located between and abutting both the valve and the movable valve seat.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Details Of Spanners, Wrenches, And Screw Drivers And Accessories (AREA)
  • Turning (AREA)
US00178553A 1971-09-08 1971-09-08 Automatic throttle shut-off power tool Expired - Lifetime US3724560A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US17855371A 1971-09-08 1971-09-08

Publications (1)

Publication Number Publication Date
US3724560A true US3724560A (en) 1973-04-03

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ID=22652995

Family Applications (1)

Application Number Title Priority Date Filing Date
US00178553A Expired - Lifetime US3724560A (en) 1971-09-08 1971-09-08 Automatic throttle shut-off power tool

Country Status (9)

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US (1) US3724560A (it)
JP (1) JPS5623755B2 (it)
BE (1) BE788418A (it)
CA (1) CA956207A (it)
DE (1) DE2241378A1 (it)
FR (1) FR2152157A5 (it)
GB (1) GB1346400A (it)
IT (1) IT967167B (it)
SE (1) SE398060B (it)

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3908766A (en) * 1973-05-23 1975-09-30 Bosch Gmbh Robert Impact wrench
US3993145A (en) * 1973-07-18 1976-11-23 Robert Bosch G.M.B.H. Power tool
US4846287A (en) * 1986-05-14 1989-07-11 Rune Ericsson Impact apparatus
US5183121A (en) * 1990-11-09 1993-02-02 Permon, Statni Podnik Pan Submersible pneumatic drilling unit
US5358062A (en) * 1992-07-29 1994-10-25 Andreas Stihl Portable handheld drilling apparatus
US6244358B1 (en) 2000-01-13 2001-06-12 Snap-On Technologies, Inc. Trigger and clutch arrangement for power tools
US6253647B1 (en) 2000-01-05 2001-07-03 Snap-On Technologies, Inc. Reversible ratchet with remote reversing operating mechanism
US6675908B1 (en) * 1999-07-20 2004-01-13 Robert Bosch Gmbh Drilling hammer or impact hammer
US20090301744A1 (en) * 2008-06-06 2009-12-10 Swinford Jerry L Jet Hammer
US20100276169A1 (en) * 2008-04-22 2010-11-04 Grand Gerard M Impact mechanism
US9776314B1 (en) * 2017-06-20 2017-10-03 Jason Swinford Dual impact fluid driven hammering tool
US10113381B2 (en) 2014-01-28 2018-10-30 Coil Tubing Technology, Inc. Downhole amplification tool
US10363651B2 (en) * 2015-09-28 2019-07-30 Caterpillar Inc. Hammer assembly

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2828379A1 (de) * 1978-06-28 1980-01-10 Gardner Denver Gmbh Motorbetriebenes werkzeug, insbesondere handgefuehrtes druckluft-schraubwerkzeug
US4223745A (en) * 1978-09-15 1980-09-23 Cooper Industries, Inc. Torque responsive motor shutoff mechanism for fluid operated tool

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3498389A (en) * 1968-07-03 1970-03-03 Ingersoll Rand Co Automatic throttle torque-responsive power tool
US3512591A (en) * 1968-09-05 1970-05-19 Dorothy E Kulman Control for torque producing tool
US3512590A (en) * 1968-06-12 1970-05-19 Ingersoll Rand Co Automatic throttle torque-responsive power tool

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3387669A (en) * 1966-01-20 1968-06-11 Ingersoll Rand Co Impact wrench torque-measuring device

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3512590A (en) * 1968-06-12 1970-05-19 Ingersoll Rand Co Automatic throttle torque-responsive power tool
US3498389A (en) * 1968-07-03 1970-03-03 Ingersoll Rand Co Automatic throttle torque-responsive power tool
US3512591A (en) * 1968-09-05 1970-05-19 Dorothy E Kulman Control for torque producing tool

Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3908766A (en) * 1973-05-23 1975-09-30 Bosch Gmbh Robert Impact wrench
US3993145A (en) * 1973-07-18 1976-11-23 Robert Bosch G.M.B.H. Power tool
US4846287A (en) * 1986-05-14 1989-07-11 Rune Ericsson Impact apparatus
US5183121A (en) * 1990-11-09 1993-02-02 Permon, Statni Podnik Pan Submersible pneumatic drilling unit
US5358062A (en) * 1992-07-29 1994-10-25 Andreas Stihl Portable handheld drilling apparatus
US6675908B1 (en) * 1999-07-20 2004-01-13 Robert Bosch Gmbh Drilling hammer or impact hammer
US6253647B1 (en) 2000-01-05 2001-07-03 Snap-On Technologies, Inc. Reversible ratchet with remote reversing operating mechanism
US6244358B1 (en) 2000-01-13 2001-06-12 Snap-On Technologies, Inc. Trigger and clutch arrangement for power tools
US20100276169A1 (en) * 2008-04-22 2010-11-04 Grand Gerard M Impact mechanism
US8371394B2 (en) * 2008-04-22 2013-02-12 Gerard Grand Impact mechanism
US20090301744A1 (en) * 2008-06-06 2009-12-10 Swinford Jerry L Jet Hammer
US9038744B2 (en) * 2008-06-06 2015-05-26 Coil Tubing Technology, Inc. Jet hammer
US10113381B2 (en) 2014-01-28 2018-10-30 Coil Tubing Technology, Inc. Downhole amplification tool
US10363651B2 (en) * 2015-09-28 2019-07-30 Caterpillar Inc. Hammer assembly
US9776314B1 (en) * 2017-06-20 2017-10-03 Jason Swinford Dual impact fluid driven hammering tool

Also Published As

Publication number Publication date
FR2152157A5 (it) 1973-04-20
JPS5623755B2 (it) 1981-06-02
IT967167B (it) 1974-02-28
SE398060B (sv) 1977-12-05
JPS4836800A (it) 1973-05-30
BE788418A (fr) 1973-01-02
CA956207A (en) 1974-10-15
DE2241378A1 (de) 1973-03-15
GB1346400A (en) 1974-02-06

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