US3661040A - Pneumatic nutrunner with work marking mechanism - Google Patents

Pneumatic nutrunner with work marking mechanism Download PDF

Info

Publication number
US3661040A
US3661040A US44417A US3661040DA US3661040A US 3661040 A US3661040 A US 3661040A US 44417 A US44417 A US 44417A US 3661040D A US3661040D A US 3661040DA US 3661040 A US3661040 A US 3661040A
Authority
US
United States
Prior art keywords
marking
plunger
nutrunner
marking rod
rod
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
US44417A
Other languages
English (en)
Inventor
Richard S Lesner
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.)
Chicago Pneumatic Tool Co LLC
Original Assignee
Chicago Pneumatic Tool Co LLC
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 Chicago Pneumatic Tool Co LLC filed Critical Chicago Pneumatic Tool Co LLC
Application granted granted Critical
Publication of US3661040A publication Critical patent/US3661040A/en
Assigned to NATIONAL WESTMINSTER BANK USA reassignment NATIONAL WESTMINSTER BANK USA SECURITY INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: CHICAGO PNEUMATIC TOOL COMPANY
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

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
    • B25B23/15—Arrangement of torque limiters or torque indicators in wrenches or screwdrivers having a mechanism to mark the work when the selected torque is applied to the work
    • 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

  • the m is combined with a nutrunner; and in ano is a separate unit.
  • PATENTEDMAY 9 I972 SHEET 1 [IF 2 PATENTEDHAY 9:922 3,661,040
  • marking tool as a unit separate from the nutrunner may be provided for application to the work after delivery of a final torque
  • the marking mechanism be a component of the nutrunner and so associated with it as to operate automatically in response to the delivery of a final torque to the work.
  • a feature of the invention is a locating plunger which is operable to bring a marking rod into contact with the work regardless of the extent to which the work extends axially into the work socket.
  • Another feature lies in the provision of a reciprocating piston hammer adapted to repeatedly pound the marking rod in an arrangement in which the marking rod is adapted under such action to oscillate from side to side and simultaneously turn on its axis so as to impart a group of clearly visible marks to the head of the work.
  • Another feature lies in the manner of the association of the marking mechanism with the nutrunner whereby the air used in operating the nutrunner is caused to be diverted to operate the marking mechanism.
  • the marking mechanism is illustrated in one form in which it is incorporated in the housing of a nutrunner. In this form, it is adapted to be operated automatically following final torque delivery. It is also illustrated in a modified form as a unit separate from the nutrunner. In this latter form, it is hand operated and may be selectively applied by the operator to the work. As a separate unit, the marking mechanism may be located externally of the nutrunner; it may also be associated with other machines.
  • the first two are hand powered; and the third one is a motor driven wrench of the impact type, the marking mechanism of which operates concurrently with the motor and while final torquing is in progress.
  • FIG. I is an elevational view, partly in section, of a pneumatic nutrunner embodying the marking mechanism of the present invention
  • FIG. 2 is a schematic showing of the relation of the shut-off valve to the cam release clutch
  • FIG. 3 is a detail section of the marking mechanism, drawn to an enlarged scale for added clarity
  • FIG. 4 is a plan view of the head of a threaded fastener which has been subjected to the marking action of the marking mechanism;
  • FIG. 5 is a modified form of the marking mechanism, designed as a separate unit for use apart from the nutrunner.
  • FIGS. l4 of the drawing in which is shown a pneumatic nutrunner having a general housing 11 defined by a succession of sections connected to one another in end-to-end relation.
  • An angle head housing section 12 is detachably coupled at the end of its long arm 13 to the general housing of the tool, as at 14.
  • a shorter arm 15 of the angle head extends at an angle to the general housing; it supports a drive shaft 16 carrying a work socket 17 adapted for driving engagement with a threaded fastener, such as the nut l8 which is to be threadedly tightened upon the stud 19.
  • An inlet 21 at the rear of the tool is connectible to a source of pressure air. Operation of a throttle valve 22 in the tool allows flow of inlet air through a normally open shut-off valve 23 to drive a rotary air motor at 24 of a conventional slidable vane type.
  • the motor is drivingly connected in conventional manner through a torque release cam clutch 25 (FIG. 2) with an output spindle 26.
  • the latter extends into the long arm 13 of the angle head; and is drivingly connected by means of a bevel gear 27 with a gear 28 splined to shaft 16.
  • Gear 28 is supported in a bearing 29.
  • the clutch includes a driving member 31 with which an axially disengageable clutch member 32 is normally held engaged under the force of a clutch return spring 33.
  • the shut-off valve 23 is in the form of a disc which is guided to and from a valve seat 35 by means of a valve stem 36, the latter being slidable in a bore of a guide bushing 37.
  • a slide rod 38 having one end abutting the disengageable clutch member and having its other end abutting the valve stem, normally holds the shut-off valve in an open condition, as in FIGS. 1 and 2, during the time that the clutch is engaged.
  • clutch member 32 When the nut 18 has been tightened upon the stud 19 to a preset degree, clutch member 32 is forced by the torque reaction axially away from the driving clutch member 31 against the force of the clutch spring 33.
  • the slide rod 38 under force of inlet air supplemented by the force of a spring 39 acting upon the head of the shut-off valve, follows the disengaging clutch member until the valve closes upon its seat. The inlet air is thus shut off from the motor, causing the latter to stop.
  • the clutch however, remains held by the rod in its disengaged condition under pressure of inlet air acting over the seated shut-off valve. This condition will continue until the operator releases the throttle valve 22 to closed condition.
  • a nutrunning tool of the foregoing general construction and mode of operation is described in detail in US. Pats. Nos. 3,298,481 and 3,187,860.
  • the drive shaft 16 has been improved to serve not only as a drive shaft for the nutrunner but also as a housing for metal marking mechanism 40 (FIGS. I and 3); and the shut-off valve 23 has been modified so that following shut-off of inlet air to the motor a restricted volume of inlet air will automatically be diverted to operate the marking mechanism. Inlet air pressure over the head of the shut off valve 23 remains adequate to hold the valve closed despite the restricted air volume being diverted to the marking mechanism.
  • a passage 41 in its stern connects with ports 42 in the guide bushing 37 so as to allow inlet air to pass through the valve stem to a housing port 44.
  • the latter port connects by means of an external flexible hose line 45 with a port 46 leading into the marking mechanism.
  • the drive shaft 16 is shown here as extending at right angles to the longitudinal axis of the general housing of the tool. It comprises a pair of hollow cylindrical sections 47 and 48 which are threadedly coupled together, as at 49, in axial extension of one another.
  • the upper shaft section 47 is rotatably supported in bearings 50 and 51 and extends through a cap 52 threadedly plugged in an open end of the angle head.
  • a terminal stem 53 of the lower drive shaft section 48 is received axially in a rear opening of the socket 17 and is releasably retained therein by means of a spring loaded latch pin 54.
  • the socket has a multi-sided recess 55 in its end which is adapted to engage over the nut 18. Above the socket recess is an elongated space 56 into which an end of the stud 19 may progress as the nut is tightened.
  • the drive shaft 16 defines a housing for the marking mechanism. Its interior provides a chamber 57 in which a hollow plunger 58 of the marking mechanism is reciprocable.
  • a head 59 of a marking rod holder 61 is threadedly plugged in an open front end of the plunger.
  • a reduced tubular portion 62 depends axially from the head with a slide fit through the stem 53 of the drive shaft and projects part way into the socket space 56 in axial alignment with the stud 19.
  • Tube 62 is of lesser outer diameter than the stud.
  • a spring loaded ball latch 63 cooperates with a flat 64 at the upper side of a cylindrical metal marking rod 65 to releasably retain the latter in the holder.
  • the flat is longer in its longitudinal dimension than the diameter of the ball latch so as to permit limited axial movement or loss-motion of the marking rod relative to the holder.
  • the transverse dimension of the flat corresponds substantially to that of the diameter of the ball latch.
  • a piston 66 is pneumatically reciprocable in a piston cylinder 67 of the marking mechanism to repeatedly hammer an anvil 68 against the marking rod.
  • Cylinder 67 is disposed within the interior of the plunger 58.
  • a pin 69 anchored at its ends in the plunger extends, in order, through the upper end of cylinder 67 and through the head of a cylindrical guide rod 71 so that these connected elements move with the plunger as a unit.
  • the guide rod 71 carries an O-ring seal 72 at its upper end.
  • the cylinder has a peripheral land 73 between its ends which bears upon the inner wall of the plunger so as to define upper and lower annular clearances or chambers 74 and 75.
  • An O-ring 76 in the land seals the clearances from one another.
  • anvil 68 The body of anvil 68 is slidable in the head 59 of the marking rod holder above the marking rod.
  • an annular flange 77 at the base of its head 78 abuts against an open bottom end of the cylinder; and its head projects into the cylinder where it is subject to the pounding of the piston.
  • An O-ring cushion 79 is provided for cushioning movement of the anvil,
  • the marking rod has a dropped position wherein the upper shoulder of its flat 64 abuts the ball latch 63, and a pointed stylus end 80 of the marking rod projects slightly below the bottom of the holder tube 62, as appears in FIG. 1.
  • the socket 17 is applied to the nut 18 and the throttle valve 22 is depressed causing pneumatic operation of the motor 24.
  • the torque of the motor is transmitted through the drive shaft 16 and the socket to tighten the nut upon the stud 19.
  • inlet air is blocked by the open condition of the shutoff valve 23 and the unregistered condition of its ports from flowing through the hose line 45 to the marking mechanism 40.
  • the marking mechanism at this time has, as in FIG. I, an inactive condition wherein the plunger 58 is biased by its return spring 81 to an upper normal position in which a shoulder of the plunger abuts an internal shoulder 82 of the drive shaft, and its upper stem 83 is fully received in a complementary portion of the plunger chamber 57. In this inactive condition, the holding tube 62 and marking rod 65 are held by the plunger clear of the work.
  • inlet air is shut-off from the motor and rotation of the drive shaft 16 stops. Inlet air is then diverted through the connected passages 41, 42 of the shut-off valve and valve bushing to the hose 45.
  • the live air entering the angle head from hose 45 passes through a bore 84 in the drive shaft to a shallow inlet compartment 85 above the stem 83 of plunger 59. Live air entering compartment 85 acts upon the plunger to force it gently downward against the resistance of its spring 81 until the open end of the holding tube 62 limits upon the top of the stud 19.
  • the marking rod 65 descends with the holding tube, it eventually engages the top of the stud and is then slidably retracted in the holder to take up the loss-motion permitted by the ball latch 63 and flat 64.
  • the retracted movement of the marking rod raises the anvil so as to seat its flange 77 against the open end of the piston cylinder 67.
  • the weight of the tool prevents the socket 17 from being forced free of the work in this action.
  • the inlet air is forcing the plunger downward, it also is flowing through a passage 86 to the interior area of the plunger defined by the upper clearance 74. The air then flows from clearance 74 through side ports 87 to an annular chamber 88 defined about the piston.
  • the plunger continues to be held downward with its tube 62 in contact with stud 19 during the entire time that the piston is reciprocating.
  • the stylus tip 80 of the marking rod is formed of hard metal such as carbide steel. It repeatedly marks or dents the surface of the stud 19 under a rapid succession of impacts imparted to the stud by the anvil. It is desired that the markings will not be one upon the other in a single spot but that multiple markings will be produced.
  • the marking rod 65 has a loose fit in the holding head 59 and in the holding tube 62. Since there is a slight circumferential looseness at the upper end of the marking rod in the holding head, the marking rod tends to oscillate sideways in the tube 62 and to turn on its axis as it is subjected to repeated hammering by the piston.
  • the tube serves to curb the extent of side-to-side swinging of the marking rod.
  • This oscillating action causes a group of marks to be indented in the top of the stud 19 in a general circular pattern, as indicated at 100 in FIG. 4. There is also a slight looseness between the opposed ends of the anvil and the marking rod which permits the marking rod to rebound slightly following impact.
  • the socket space 56 above the work is adequate to accommodate variations in the vertical extension of the work into the socket. It is also to be noted that the locating plunger 58 has the capacity to carry its holding tube 62 downwardly against the resistance of spring 81 until the holding tube has limited upon the work, regardless of the extent to which the work extends into the socket 17.
  • the marking mechanism is shown as combined with the angle head of a pneumatic nutrunner.
  • the marking mechanism is shown as a separate unit, independent of the nutrunner.
  • an inlet adapter section 102 has been threadedly coupled as at 103 to the upper section 47a of the units housing 16a.
  • the lower section 48 of the housing carries the socket 17 which is adapted to receive the nut 18 and stud 19.
  • the adapter 102 is provided with a throttle valve 105 and is connectible to a pressure air source by means of a feed line 104.
  • the socket is applied over work that has been previously torqued in order to center the work relative to the marking rod and holding tube; the throttle valve 105 is then actuated to effect operation of the marking mechanism and consequent repeated marking of the work.
  • the marking mechanism is shown as incorporated within the angle head section of the nut runner.
  • the marking mechanism may be a separate unit provided with its own housing. As such, it may be mounted in suitable manner as by bolting or clamping to the exterior surface of the nutrunner either at the rear of the angle head section or at some other selected area.
  • its inlet may be connected with the hose line 45; or it may be connected by the hoseline 104 with an independent source of operating air. Where the inlet is connected with the hoseline 45 of the nutrunner, the throttle valve 105 may be omitted.
  • the marking mechanism may also be associated with various types of automatic machines. When so applied, its housing would be mounted to a suitable work station and its mechanism caused to be operated at a precise time by means of suitable air flow controls operatively associated with the automatic machine.
  • the socket element 17 When so used, the socket element 17 may be used where the work is concerned with nutrunning; or the socket element may be omitted, when it is only required to mark the work, whatever it may be, to indicate that the work has passed through a final work stage.
  • marking mechanism is used as a separate unit that its housing may be designed, as needed, to facilitate its mounting or positioning.
  • a nutrunner comprising a rotary air driven motor, a hollow work shaft carrying a socket at its end adapted to fit over a nut threaded upon a stud, a spindle having a driving connection with the shaft, a torque disengageable clutch drivingly connecting the motor to the spindle adapted to disengage upon the nut being tightened to a predetermined torque value, pneumatically operable marking mechanism housed in the shaft for applying marks repeatedly in rapid succession to the stud, slidable valve means controlling flow of live air to both the motor and to the marking mechanism having a normal position allowing live air flow to the motor to operate it and blocking live air flow to the marking mechanism, the valve means having a second position blocking live air flow to the motor so as to cause the motor to stop and allowing live air flow to the marking mechanism so as to cause it to operate, and means having response to disengaging of the clutch for causing the valve to move to its second position and holding it in said position.
  • a nutrunner as in claim 2 wherein a conduit arranged externally of the nutrunner connects the valve means with an inlet to the marking mechanism.
  • the marking mechanism includes a locating plunger carrying a marking rod, the plunger being pneumatically movable in one direction to carry the marking rod into abutment with a fastener engaged by the socket, and a spring is provided in the shaft for re-turning the plunger and marking rod away from the fastener to a normal inactive position.
  • a nutrunner as in claim 4 wherein a pneumatically reciprocable piston is arranged within the plunger for applying repeated impacts to the marking rod.
  • passage means communicates an air inlet of the marking mechanism with both the plunger and the piston.
  • a pneumatically driven torque release wrench having a driving member conneetible to a threaded fastener for tightening the same to a predetermined torque value; marking mechanism housed in said driving member for applying marks repeatedly in rapid succession to the fastener after said predetermined torque value has been obtained; and means having response to the application of said predetermined torque value to cause the driving member to stop operating and to cause the marking mechanism to operate.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Details Of Spanners, Wrenches, And Screw Drivers And Accessories (AREA)
  • Shaping Metal By Deep-Drawing, Or The Like (AREA)
US44417A 1970-06-08 1970-06-08 Pneumatic nutrunner with work marking mechanism Expired - Lifetime US3661040A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US4441770A 1970-06-08 1970-06-08

Publications (1)

Publication Number Publication Date
US3661040A true US3661040A (en) 1972-05-09

Family

ID=21932279

Family Applications (1)

Application Number Title Priority Date Filing Date
US44417A Expired - Lifetime US3661040A (en) 1970-06-08 1970-06-08 Pneumatic nutrunner with work marking mechanism

Country Status (5)

Country Link
US (1) US3661040A (OSRAM)
CA (1) CA930987A (OSRAM)
DE (1) DE2127871A1 (OSRAM)
FR (1) FR2095993A5 (OSRAM)
GB (2) GB1349202A (OSRAM)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3802301A (en) * 1971-05-27 1974-04-09 Carco Inc Marking device for torque applying tool
US6588962B1 (en) 2002-03-26 2003-07-08 Honda Giken Kogyo Kabushiki Kaisha Gap checking device with automatic paint application
US20140165795A1 (en) * 2011-08-02 2014-06-19 Korea Electric Power Corporation Wrench socket for automatically marking high tension bolt, and method for tightening high tension bolt using same
US9289886B2 (en) 2010-11-04 2016-03-22 Milwaukee Electric Tool Corporation Impact tool with adjustable clutch
US20180340566A1 (en) * 2017-05-25 2018-11-29 Hyundai Motor Company Nut runner

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1389395A (en) * 1972-05-11 1975-04-03 Rockwell International Corp Fastener tool
GB2092494A (en) * 1981-02-11 1982-08-18 Ford Motor Co Torque tool with marking stylus
DE102015204979A1 (de) * 2015-03-19 2016-09-22 Bayerische Motoren Werke Aktiengesellschaft Montagewerkzeug mit Markierfunktion sowie Verfahren zum Ausbilden von Markierungen in Befestigungselementen mittels eines Montagewerkzeugs
CN106112501A (zh) * 2016-08-24 2016-11-16 中山市鑫光智能系统有限公司 可调节间距的打螺丝装置

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2986052A (en) * 1958-10-27 1961-05-30 Reed Roller Bit Co Predetermined torque responsive hand tool
US3009371A (en) * 1960-05-11 1961-11-21 Albert O Hines Automatic work marking means for predetermined torque release wrench
US3263785A (en) * 1964-07-31 1966-08-02 Ingersoll Rand Co Torque releasing clutch mechanism and motor control
US3288258A (en) * 1964-08-24 1966-11-29 Ingersoll Rand Co Torque releasing clutch mechanism
US3298481A (en) * 1963-07-10 1967-01-17 Chicago Pneumatic Tool Co Torque release and shut off device for rotary pneumatic tools
US3389623A (en) * 1966-01-18 1968-06-25 G K N Group Service Ltd Method of tightening high strength bolts and apparatus for use therein
US3523471A (en) * 1967-11-08 1970-08-11 Christopher James Lance Precision torque release and part marking wrench

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2986052A (en) * 1958-10-27 1961-05-30 Reed Roller Bit Co Predetermined torque responsive hand tool
US3009371A (en) * 1960-05-11 1961-11-21 Albert O Hines Automatic work marking means for predetermined torque release wrench
US3298481A (en) * 1963-07-10 1967-01-17 Chicago Pneumatic Tool Co Torque release and shut off device for rotary pneumatic tools
US3263785A (en) * 1964-07-31 1966-08-02 Ingersoll Rand Co Torque releasing clutch mechanism and motor control
US3288258A (en) * 1964-08-24 1966-11-29 Ingersoll Rand Co Torque releasing clutch mechanism
US3389623A (en) * 1966-01-18 1968-06-25 G K N Group Service Ltd Method of tightening high strength bolts and apparatus for use therein
US3523471A (en) * 1967-11-08 1970-08-11 Christopher James Lance Precision torque release and part marking wrench

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3802301A (en) * 1971-05-27 1974-04-09 Carco Inc Marking device for torque applying tool
US6588962B1 (en) 2002-03-26 2003-07-08 Honda Giken Kogyo Kabushiki Kaisha Gap checking device with automatic paint application
US9289886B2 (en) 2010-11-04 2016-03-22 Milwaukee Electric Tool Corporation Impact tool with adjustable clutch
US20140165795A1 (en) * 2011-08-02 2014-06-19 Korea Electric Power Corporation Wrench socket for automatically marking high tension bolt, and method for tightening high tension bolt using same
US9393679B2 (en) * 2011-08-02 2016-07-19 Korea Electric Power Corporation Wrench socket for automatically marking high tension bolt, and method for tightening high tension bolt using same
US20180340566A1 (en) * 2017-05-25 2018-11-29 Hyundai Motor Company Nut runner
KR20180129199A (ko) * 2017-05-25 2018-12-05 현대자동차주식회사 너트 런너
US10563688B2 (en) * 2017-05-25 2020-02-18 Hyundai Motor Company Nut runner

Also Published As

Publication number Publication date
FR2095993A5 (OSRAM) 1972-02-11
GB1349202A (en) 1974-04-03
DE2127871A1 (de) 1971-12-16
CA930987A (en) 1973-07-31
GB1349201A (en) 1974-04-03

Similar Documents

Publication Publication Date Title
US3774479A (en) Pneumatic marking device
US3661040A (en) Pneumatic nutrunner with work marking mechanism
US3571874A (en) Descaling device
US5210918A (en) Pneumatic slide hammer
US3710873A (en) Impact wrench or screwdriver
US5073068A (en) Peck feed drilling machine
US3162250A (en) Torque control means for power tools
US2674098A (en) Portable power-driven tool for drilling and like operations
US2821276A (en) Rotary impact tool
US3747441A (en) Pneumatic tool having combined nut running and crimping mechanism
US2929134A (en) Rotation and impact tool
US3802301A (en) Marking device for torque applying tool
US3791458A (en) Stall torque air shut-off control for pneumatic nut runners
US2518049A (en) Pneumatic screw driver
US3498389A (en) Automatic throttle torque-responsive power tool
US3693483A (en) Torque power wrench marking device
US4511295A (en) Pneumatic collet release tool
JPS6240139B2 (OSRAM)
US2734402A (en) hoern
US3719111A (en) Marking device for torque applying tool
US6755260B1 (en) Pneumatic tool
US2644964A (en) Nipple threading machine
US3093114A (en) Percussion tool for tightening and loosening bolts and nuts
US2395018A (en) Automatic feed for drills
US3260138A (en) Attachment for a hand drill or the like

Legal Events

Date Code Title Description
AS Assignment

Owner name: NATIONAL WESTMINSTER BANK USA, 175 WATER STREET, N

Free format text: SECURITY INTEREST;ASSIGNOR:CHICAGO PNEUMATIC TOOL COMPANY;REEL/FRAME:004681/0047

Effective date: 19861230