US3841028A - Apparatus for handling workpieces to be polished - Google Patents

Apparatus for handling workpieces to be polished Download PDF

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Publication number
US3841028A
US3841028A US00283582A US28358272A US3841028A US 3841028 A US3841028 A US 3841028A US 00283582 A US00283582 A US 00283582A US 28358272 A US28358272 A US 28358272A US 3841028 A US3841028 A US 3841028A
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US
United States
Prior art keywords
workpieces
tool
arm
platen
workholder
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
US00283582A
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English (en)
Inventor
E Katzke
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.)
Crane Packing Co
John Crane Inc
Original Assignee
Crane Packing Co
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 Crane Packing Co filed Critical Crane Packing Co
Priority to US00283582A priority Critical patent/US3841028A/en
Priority to GB3742273A priority patent/GB1409776A/en
Priority to CA178,676A priority patent/CA987111A/en
Priority to FR7330775A priority patent/FR2197333A5/fr
Priority to DE19732342900 priority patent/DE2342900C3/de
Application granted granted Critical
Publication of US3841028A publication Critical patent/US3841028A/en
Assigned to JOHN CRANE HOUDAILLE, INC. A CORP. OF reassignment JOHN CRANE HOUDAILLE, INC. A CORP. OF MERGER (SEE DOCUMENT FOR DETAILS). Assignors: CRANE PACKING COMPANY A CORP. OF IL.
Assigned to JOHN CRANE-HOUDAILLE, INC. reassignment JOHN CRANE-HOUDAILLE, INC. ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: HOUDAILLE-JOHN CRANE, INC., A CORP. OF DE
Assigned to JOHN CRANE INC. reassignment JOHN CRANE INC. CHANGE OF NAME (SEE DOCUMENT FOR DETAILS). EFFECTIVE: MARCH 21, 1988, DELAWARE Assignors: JOHN CRANE-HOUDAILLE, INC.
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
    • B24B37/00—Lapping machines or devices; Accessories
    • B24B37/34—Accessories
    • B24B37/345—Feeding, loading or unloading work specially adapted to lapping
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
    • B24B41/00—Component parts such as frames, beds, carriages, headstocks
    • B24B41/06—Work supports, e.g. adjustable steadies

Definitions

  • an apparatus for handling workpieces to be polished on a rotatable disc type of polishing machine comprising a workholder mounted on an arm oscillatable in a vertical plane through substan tially 180 so that in one position the workholder is inverted to facilitate loading and unloading thereof, and in another position the workholder supports the workpieces by differential pressure thereon over the polishing disc.
  • the movement of the arm may be arrested as the workpieces touch the polishing disc, and an air cylinder on the arm moves the workholder against the disc and presses the workholder against the disc with a higher pressure than is permissible with wax-adhered workpieces.
  • the workholder is raised from the polishing disc and the arm is rotated to invert the workholder, after which a cleaning spray is automatically applied to the workpieces.
  • silicon wafer An important component used in the electronic art is the silicon wafer. This wafer varies from 0.005 inch to 0.015 inch thick and is disc-shaped in outline. It is important for its electrical characteristics that such wafer is made with parallel, highly polished surfaces, and that for uniformity the polishing be done automatically and under controlled conditions.
  • Rotating disc-shaped polishing tools have been used for polishing wafers, the latter being adhered by wax to a flat platen which is pressed against the rotating tool and held there for a predetermined time.
  • the higher pressures however, increase the friction between the wafer and polishing disc which then heats up the wafer and melts the wax holding the wafer to the holder.
  • the wafers thus loosened are destroyed, as are those at other stations on the polishing machine contacted by the loose wafers, resulting in an appreciable monetary loss to the polisher.
  • this invention seeks to provide a pressure-differential operated arm on which is mounted a workholder, the arm being oscillated about a horizontal axis, wherein the mounting for the workholder on the arm includes a pressure-differential operated motor for providing operating pressure to the workholder, with control means automatically operated by the position of the arm for applying and releasing the pressure, and with timer means for moving the arm to invert the workholder and to apply a cleansing spray to the workpieces.
  • FIG. I is a plan view of a polishing machine incorporating this invention
  • FIG. 2 is a side elevational view, partly in section of the machine of FIG. 1;
  • FIG. 3 is a side elevational view, partly in section and on an enlarged scale of the workholder of this invention.
  • FIG. 4 is a schematic diagram of the controls for the workholder of FIG. 3.
  • the form of polishing machine selected to illustrate this invention is shown in plan view in FIG. I.
  • the workpieces are thin wafers of silicon or the like used as electronic components and are of disc form.
  • the flat surfaces of the wafers are required to be polished to a predetermined standard, and with the polishing cycle calculated to produce such standard polish upon the wafers and the time required to load and unload a workholder it has been determined in the illustrative machine that a single polishing disc with four work stations could be readily tended by one operator.
  • the machine shown in FIG. I is comprised of a frame 10 on which is mounted a polishing disc 11 rotatable'about a vertical axis and driven by an appropriate motor shown at 12 in FIG. 2.
  • a control panel 13 extends over disc 11 in proximity to four work stations 14, 15, 16 and 17 and contains four sets of manuallyoperated switches only one of which sets is shown in outline at 18. One set of switches is supplied for each I station.
  • a separate master control panel 19 is located on a post 20 supporting the sets 18 of station switches.
  • Said master control panel contains switches (not shown) for controlling l motor 12 for driving disc 1 l, (2) a vacuum pump for generating the vacuum used to hold the wafers on the workholder, (3) a polishing compound pump for supplying the disc with abrasive for the polishing operation and (4) a master switch which controls the electrical energy to the entire machine.
  • the four work stations 14, 15, 16 and 17 and their controls are identical and hence for brevity only one station 17 will be described.
  • Said station is shown in elevation in FIG. 2 and in enlarged elevation in section in FIG. 3.
  • AS shown in FIG. 2 it is comprised of a vertically disposed pneumatic rotary actuator 21 which is essentially a pneumatic cylinder 22 (FIG. 3) the rod 23 of which carries a gear rack 24 meshing with a pinion 25 the shaft of which is connected to an arm 26.
  • a workholder, shown generally at 27 in FIG. 2 is mounted on the end of arm 26 through a pressuredifferential operated motor 28, said arm in one position overlying polishing disc 11 and pressing the workpieces upon the surface of said disc and in another position, shown dotted in FIG. 2, substantially away from the said one position, supporting the workholder 27 in an inverted position so that the workpieces rest on top of the holder and can readily be placed upon and removed from the workholder.
  • the cylinder 22 of pneumatic rotary actuator 21 is double acting and has ports 29 and 30 leading to opposite sides of a piston 31 therein.
  • the workholder 27, as shown more clearly in FIG. 3, comprises a plate 36 preferably circular in outline and having a flat surface 37 upon which the workpieces 38 are held by differential pressure.
  • surface 37 is provided with relieved areas under the workpieces 38 connected by passages 39 to a source of subatmospheric pressure.
  • the details of construction of the relieved areas are disclosed in my co-pending application for APPARATUS FOR POLISHING WAFERS filed Nov. 29, 1971 Ser. No. 202,965.
  • Plate 36 is secured to a piston rod 40 of a double acting pressure-differential operated motor 41 having ports 42, 43 for conducting fluid under pressure to one side or the other of the piston 44 of motor 41.
  • Motor 41 is secured to the end of arm 26 and hence is movable therewith. It is contemplated that arm 26 will be rotated through 180 to invert workholder 36 so that the workpieces can be readily loaded upon and unloaded from said workholder. It is also contemplated that workholder 36 will be moved and held against the polishing disc 11 to press the workpieces thereagainst and thus accelerate the polishing process. Finally, it is desirable that the polished workpieces, while still on the workholder, be sprayed with water to wash off any polishing compound that may adhere to them.
  • the motive fluid for cylinder 29 and motor 41 is air under pressure.
  • hydraulic power can also be used, it involves the use of a separate pump, a reservoir and filters, all of which add to the cost of the machine.
  • the motive power for the water spray valve is also air under pressure controlled by a solenoid-operated valve.
  • FIG. 4 the components of the machine and its controls are shown schematically in FIG. 4.
  • the sequence of operations for a full cycle at one station is as follows, assuming that the disc has been set in rotation and the polishing compound is flowing upon the rotating disc: (1) the workholder is loaded with workpieces (manual); (2) the vacuum is turned on to establish the differential pressure by which the workpieces are held on the workholder (manual); (3) a switch is turned on to start the timer for the polishing cycle (manual); (4) arm 26 is rotated to a positive stop where the workholder holds the workpieces just above the disc.
  • air under pressure is connected to a station supply pipe 45 from which it is conducted through a pipe 46 to a solenoidoperated valve 47 and thence as dictated by valve 47 to ports 42 and 43 on motor 41 the function of which is to move workholder 36 against polishing disc 11.
  • a second branch pipe 47 conducts air under pressure to an air valve 48 which controls a small pressure differential motor on a water valve 49 controlling in turn the spray water from a water line 50.
  • Pipe 45 is connected to a valve 51 which controls the admission of air under pressure to cylinder 22 of the fluid actuator 21 (FIG. 2) for arm 26.
  • Valves 47, 48 and 51 are solenoid operated to open and springreturned to closed position.
  • the solenoids in turn are controlled by timers 52, 53 and 54, timer 52 controlling the polishing cycle and being manually adjustable to the length of time required to polish a workpiece, and timers 53 and 54 being fixed as to duration and designed to produce a short delay in the application of electric current to the solenoid valves operated thereby.
  • Each station has a manually-operated start switch 55 which controls all electrical equipment for that station and a manually-operated cycle switch 56 which energizes timer 52 to start the polishing cycle.
  • cylinder 22 is in the position wherein its piston and attached gear rack 23 are in their lowermost position.
  • Workholder plate 36 is therefore in its inverted position radially removed from polishing disc 1 1 and ready to be loaded.
  • the vacuum has been turned off by manually-operated switch 57 which controls the solenoid-operated valve 58 for the vacuum to plate 36. workpieces are placed upon plate 36 over the areas influenced by vacuumas described in detail in my afore-.
  • timer 52 actuates a series of switches 58, S9, 60 and 61 which are reversed when the timer times out.
  • Switch 58 is a holding switch for timer 52 so that manual switch 56 need not be held down during the polishing cycle.
  • Switch 59 energizes a solenoid 62 on air valve 51 to cause said valve to admit air under pressure to the bottom of actuator 22 and thus raise rack 23 to rotate pinion 25 and arm 26 toward polishing disc 11.
  • limit switch 34 When rack 23 reaches the end of its stroke, limit switch 34 is actuated to activate timer 53 which when it times out energizes a solenoid 63 on valve 47 to admit air under pressure to port 42 of pressure cylinder 41 and thus move workholder plate 36 toward polishing disc 11 and hold it against the disc with a predetermined pressure. Since the polishing disc had been set in motion previously and remains in motion until the machine is to be shut down, the polishing operation commences and continues until timer 52 times out.
  • switches 58 and 59 are opened and switch 60 is closed to energize a solenoid 68 on valve 51 to condition said valve to admit air under pressure to the top of cylinder 22 which lowers rack 23 and raises workholder plate 36 off the polishing disc ll.
  • a switch 61 is closed by timer 52 which energizes a solenoid 65 on valve 47 to remove air pressure from plate 36 and to raise said plate with respect to cylinder 41.
  • limit switch 35 Upon completion of the reverse rotation of arm 26, limit switch 35 is activated by abutment 33 to energize a solenoid 66 on air valve 48 the air from which then operates water valve 49 to spray water upon the polished workpieces.
  • a timer 54 is activated simultaneously with solenoid 66 and when it times out, a switch 67 is opened to de-energize solenoid 66 and thus, through the spring-returned valves 48 and 49 shut off the water to the spray.
  • Vacuum switch 57 is then opened to remove differential pressure from the workpieces and the polished workpieces are subsequently removed and replaced with workpieces to be polished. The operator moves to the next station that has timed out and that is ready for removal of polished workpieces and loading of workpieces to be polished.
  • the machine herein described thus automatically brings the workpieces to the polishing disc, brings pressure to bear upon the workpieces while they are being polished, to speed up the polishing operation both from the standpoint of increased abrading action as well as of disintegration through chemical action which is accelerated by the increased temperature of the workpiece surface, removes the pressure and brings the workpieces back to the loading position.
  • Apparatus for applying workpieces to and removing them from a substantially horizontally operating abrading tool comprising a platen, means for mounting the workpieces on said platen for a movement therewith, an arm having a horizontally disposed pivot located to one side of the tool, means for oscillating said arm about its pivot through substantially 180, means for mounting the platen on the arm to cause said platen at one extreme position of the arm to assume an inverted position to permit loading of the workpieces thereon and at the other extreme position to be located over said abrading tool with the workpieces adjacent said tool, said platen mounting means comprising means for advancing said platen toward said tool independently of said arm oscillating means and independently of said workpiece mounting means, and fluid pressure means for holding said workpieces against said tool with a predetermined pressure while said tool is abrading said workpieces.
  • said means for supporting said workpieces comprising a platen having a plurality of stations thereon one for each workpiece, means at each station for applying sub-atmospheric pressure to the workpiece to hold said workpiece on the platen, manually operable means for controlling the application of subatmospheric pressure and means controlled by movement of the platen for controlling the application of the cleaning liquid.
  • said means automatically operable upon said arm reaching its extreme position opposite said first-mentioned extreme position for spraying said articles with a cleaning fluid comprising an air-operated valve, a source of air under pressure, a solenoid-operated valve for controlling application of air under pressure from said source to said airoperated valve, and a switch operated by said platen for energizing said solenoid-operated valve.
  • said tool comprising a polishing disc, and means for driving said disc about a vertical axis
  • said workpieces comprising discs of a thickness varying from 0.005 inch to 0.015 inch
  • pressure-differential operated means on said workpiece supporting means and comprising the sole means for holding said workpieces on the workpiece supporting means
  • said workpieces being of a material characterized by increased abrading action by the tool as the temperature of the material increases, and said predetermined pressure increasing the friction between the workpiece and tool thereby increasing the temperature of the workpieces above the melting point of wax to increase the abrading action of the tool thereon.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Finish Polishing, Edge Sharpening, And Grinding By Specific Grinding Devices (AREA)
US00283582A 1972-08-24 1972-08-24 Apparatus for handling workpieces to be polished Expired - Lifetime US3841028A (en)

Priority Applications (5)

Application Number Priority Date Filing Date Title
US00283582A US3841028A (en) 1972-08-24 1972-08-24 Apparatus for handling workpieces to be polished
GB3742273A GB1409776A (en) 1972-08-24 1973-08-07 Abrading apparatus
CA178,676A CA987111A (en) 1972-08-24 1973-08-13 Apparatus for handling workpieces to be polished
DE19732342900 DE2342900C3 (de) 1972-08-24 1973-08-24 Vorrichtung zum Aufgeben und Abnehmen von hinsichtlich ihrer Oberflächenbeschaffenheit plan zu bearbeitenden Werkstücken auf eine drehantreibbare bzw. von einer drehantreibbaren Stirnbearbeitungsscheibe einer Oberflachenendbearbeitungsm aschine
FR7330775A FR2197333A5 (enExample) 1972-08-24 1973-08-24

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US00283582A US3841028A (en) 1972-08-24 1972-08-24 Apparatus for handling workpieces to be polished

Publications (1)

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US3841028A true US3841028A (en) 1974-10-15

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US00283582A Expired - Lifetime US3841028A (en) 1972-08-24 1972-08-24 Apparatus for handling workpieces to be polished

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US (1) US3841028A (enExample)
CA (1) CA987111A (enExample)
FR (1) FR2197333A5 (enExample)
GB (1) GB1409776A (enExample)

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4009539A (en) * 1975-06-16 1977-03-01 Spitfire Tool & Machine Co., Inc. Lapping machine with vacuum workholder
US4141180A (en) * 1977-09-21 1979-02-27 Kayex Corporation Polishing apparatus
US4193226A (en) * 1977-09-21 1980-03-18 Kayex Corporation Polishing apparatus
US4663890A (en) * 1982-05-18 1987-05-12 Gmn Georg Muller Nurnberg Gmbh Method for machining workpieces of brittle hard material into wafers
US5398459A (en) * 1992-11-27 1995-03-21 Kabushiki Kaisha Toshiba Method and apparatus for polishing a workpiece
US5893794A (en) * 1996-02-28 1999-04-13 Ebara Corporation Polishing apparatus having robotic transport apparatus
US5957764A (en) * 1997-11-05 1999-09-28 Aplex, Inc. Modular wafer polishing apparatus and method
US6062961A (en) * 1997-11-05 2000-05-16 Aplex, Inc. Wafer polishing head drive
US6231428B1 (en) 1999-03-03 2001-05-15 Mitsubishi Materials Corporation Chemical mechanical polishing head assembly having floating wafer carrier and retaining ring
US6368189B1 (en) 1999-03-03 2002-04-09 Mitsubishi Materials Corporation Apparatus and method for chemical-mechanical polishing (CMP) head having direct pneumatic wafer polishing pressure
US20060180486A1 (en) * 2003-04-21 2006-08-17 Bennett David W Modular panel and storage system for flat items such as media discs and holders therefor

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2505712A1 (fr) * 1981-05-18 1982-11-19 Procedes Equip Sciences Ind Sa Machine a polir automatique, pour plaquettes minces, fragiles et deformables
DE3339942C1 (de) * 1983-11-04 1985-01-31 GMN Georg Müller Nürnberg GmbH, 8500 Nürnberg Bearbeiten von scheibenfoermigen Werkstuecken aus sproedbruechigen Werkstoffen
US4587768A (en) * 1983-11-28 1986-05-13 Buehler Ltd. Apparatus and method for polishing ends of fiber optics
EP0307477A4 (en) * 1987-03-10 1991-04-10 Gruzinsky Politekhnichesky Institut Imeni V.I. Lenina Machine tool for abrasive machining

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US765105A (en) * 1902-02-21 1904-07-12 American Electric Telephone Company Grinding or polishing machine.
US1275447A (en) * 1916-12-07 1918-08-13 Standard Mirror Co Machine for beveling mirrors and for analogous purposes.
US2963830A (en) * 1958-06-04 1960-12-13 Norton Co Lapping machine
US3128580A (en) * 1963-01-30 1964-04-14 Super Cut Composite lap for grinding and polishing machines
US3437543A (en) * 1965-03-09 1969-04-08 Western Electric Co Apparatus for polishing
US3579916A (en) * 1968-11-15 1971-05-25 Speedfam Corp Polishing machine

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US765105A (en) * 1902-02-21 1904-07-12 American Electric Telephone Company Grinding or polishing machine.
US1275447A (en) * 1916-12-07 1918-08-13 Standard Mirror Co Machine for beveling mirrors and for analogous purposes.
US2963830A (en) * 1958-06-04 1960-12-13 Norton Co Lapping machine
US3128580A (en) * 1963-01-30 1964-04-14 Super Cut Composite lap for grinding and polishing machines
US3437543A (en) * 1965-03-09 1969-04-08 Western Electric Co Apparatus for polishing
US3579916A (en) * 1968-11-15 1971-05-25 Speedfam Corp Polishing machine

Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4009539A (en) * 1975-06-16 1977-03-01 Spitfire Tool & Machine Co., Inc. Lapping machine with vacuum workholder
US4141180A (en) * 1977-09-21 1979-02-27 Kayex Corporation Polishing apparatus
US4193226A (en) * 1977-09-21 1980-03-18 Kayex Corporation Polishing apparatus
US4663890A (en) * 1982-05-18 1987-05-12 Gmn Georg Muller Nurnberg Gmbh Method for machining workpieces of brittle hard material into wafers
US5398459A (en) * 1992-11-27 1995-03-21 Kabushiki Kaisha Toshiba Method and apparatus for polishing a workpiece
US5893794A (en) * 1996-02-28 1999-04-13 Ebara Corporation Polishing apparatus having robotic transport apparatus
US5957764A (en) * 1997-11-05 1999-09-28 Aplex, Inc. Modular wafer polishing apparatus and method
US6062961A (en) * 1997-11-05 2000-05-16 Aplex, Inc. Wafer polishing head drive
US6231428B1 (en) 1999-03-03 2001-05-15 Mitsubishi Materials Corporation Chemical mechanical polishing head assembly having floating wafer carrier and retaining ring
US6309290B1 (en) 1999-03-03 2001-10-30 Mitsubishi Materials Corporation Chemical mechanical polishing head having floating wafer retaining ring and wafer carrier with multi-zone polishing pressure control
US6368189B1 (en) 1999-03-03 2002-04-09 Mitsubishi Materials Corporation Apparatus and method for chemical-mechanical polishing (CMP) head having direct pneumatic wafer polishing pressure
US20020077045A1 (en) * 1999-03-03 2002-06-20 Mitsubishi Materials Corporation Apparatus and method for chemical-mechanical polishing (CMP) head having direct pneumatic wafer polishing pressure
US7029382B2 (en) 1999-03-03 2006-04-18 Ebara Corporation Apparatus for chemical-mechanical polishing (CMP) head having direct pneumatic wafer polishing pressure
US7311586B2 (en) 1999-03-03 2007-12-25 Ebara Corporation Apparatus and method for chemical-mechanical polishing (CMP) head having direct pneumatic wafer polishing pressure
US20060180486A1 (en) * 2003-04-21 2006-08-17 Bennett David W Modular panel and storage system for flat items such as media discs and holders therefor

Also Published As

Publication number Publication date
GB1409776A (en) 1975-10-15
CA987111A (en) 1976-04-13
DE2342900A1 (de) 1974-03-07
DE2342900B2 (de) 1977-02-03
FR2197333A5 (enExample) 1974-03-22

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AS Assignment

Owner name: JOHN CRANE HOUDAILLE, INC. A CORP. OF DE.

Free format text: MERGER;ASSIGNOR:CRANE PACKING COMPANY A CORP. OF IL.;REEL/FRAME:003929/0373

Effective date: 19810803

Owner name: JOHN CRANE HOUDAILLE, INC. A CORP. OF, DELAWARE

Free format text: MERGER;ASSIGNOR:CRANE PACKING COMPANY A CORP. OF IL.;REEL/FRAME:003929/0373

Effective date: 19810803

AS Assignment

Owner name: JOHN CRANE-HOUDAILLE, INC., 6400 N. OAKTON STREET,

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:HOUDAILLE-JOHN CRANE, INC., A CORP. OF DE;REEL/FRAME:004686/0219

Effective date: 19870306

Owner name: JOHN CRANE-HOUDAILLE, INC.,ILLINOIS

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:HOUDAILLE-JOHN CRANE, INC., A CORP. OF DE;REEL/FRAME:004686/0219

Effective date: 19870306

AS Assignment

Owner name: JOHN CRANE INC.

Free format text: CHANGE OF NAME;ASSIGNOR:JOHN CRANE-HOUDAILLE, INC.;REEL/FRAME:005044/0684

Effective date: 19880311