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8-3. Operation Principle

(1) Before nailing (See Fig. 5 and Fig. 6.)

1) When compressed air is fed to the main body, it

fills the accumulator (        portion).

2) At the same time, the compressed air flows into

    the valve piston lower chamber of the control valve

    section and forces Valve Piston (B) [57] upward.

Compressed air is then fed through the air supply

vent and air passage to the head valve chamber.

As a result, the Head Valve Spring [8] is pushed

down to seal the Head Valve [10] and Cylinder

[17].

(2) When nailing (See Fig. 4 and Fig. 5.)

1) When Pushing Lever (A) [37] and Trigger (A) [47]

are operated together and Plunger (A) [61] is

pushed upward, the compressed air in the valve

piston lower chamber is discharged from the

bottom of Plunger (A) [61].  As a result, the

compressed air in the accumulator (        portion)

pushes down Valve Piston (B) [57], blocking the air

supply vent and opening the exhaust valve.

2) When the exhaust valve opens, the compressed

air in the head valve chamber is discharged into

the atmosphere through the air passage.

3) When the air pressure on the bottom surface of the

Head Valve [10] overcomes the strength of the

Head Valve Spring [8], the Head Valve [10] is

pushed upward.  At this time, the Head Valve [10]

seals with the Exhaust Valve Rubber [7], blocking

the passage to the exhaust vent.

4) When the Head Valve [10] goes up, the

compressed air in the accumulator flows rapidly

into the Cylinder [17], forcing the Piston [19]

downward to strike the nail.  When the Piston [19]

passes the cylinder hole, the compressed air flows

into the return air chamber and is accumulated

there.

Fig. 6  Control valve section

Fig. 5

Head valve chamber

Nail

Air passage

Control
valve
section

Cylinder hole

Head Valve
Spring [8]

Exhaust vent

Exhaust Valve Rubber [7]

Head Valve [10]

Cylinder [17]

Return air
chamber

Pushing Lever (A) [37]

Piston [19]

Accumulator

Trigger (A) [47]

To the head valve chamber

Plunger (A) [61]

Valve Piston (B)
[57]

Valve piston lower chamber

Exhaust
valve

Air passage

Accumulator

Air supply vent

Summary of Contents for NR 90AC3

Page 1: ...TECHNICAL DATA AND SERVICE MANUAL STRIP NAILER NR 90AC3 SPECIFICATIONS AND PARTS ARE SUBJECT TO CHANGE FOR IMPROVEMENT LIST No E013 Sep 2003 N MODEL NR 90AC3 Hitachi Power Tools ...

Page 2: ...AND SERVICE MANUAL a symbol s is are used in the place of company name s and model name s of our competitor s The symbol s utilized here is are as follows Symbols Utilized Competitors Company Name Model Name P SENCO SN65C Q Paslode F 350SRH ...

Page 3: ...echanism 9 8 2 Interchangeability 10 8 3 Operation Principle 12 9 TROUBLESHOOTING GUIDE 15 9 1 Troubleshooting and Correction 15 9 2 Possible Causes and Correction of Air Leakage 18 10 DISASSEMBLY AND REASSEMBLY 20 10 1 General Precautions in Disassembly and Reassembly 20 10 2 Disassembly and Reassembly of the Output Section 21 10 3 Disassembly and Reassembly of the Control Valve Section 23 10 4 D...

Page 4: ...knob was added to select the nailer operation between single actuation single sequential actuation and contact actuation the current Model NR 90AC2 is provided with the contact actuation mechanism only Except the above the construction is common to the current Model NR 90AC2 as well as the features such as driving response and balance 3 APPLICATIONS Floor and wall framing Truss build up window bui...

Page 5: ...32 x 5 11 32 Nose cap Code No 881968 1 Hex bar wrench for M5 screw Code No 944458 1 Hex bar wrench for M6 screw Code No 944459 1 Hex bar wrench for M8 screw Code No 872422 1 Safety glasses Code No 875769 1 Full sequential actuation mechanism kit Code No 884142 Sequential trip mechanism kit Pneumatic tool lubricant 1 oz oil feeder Code No 877153 Pneumatic tool lubricant 4 oz oil feeder Code No 8740...

Page 6: ...M First press the pushing lever against the wood next pull the trigger to drive the nail First pull the trigger next press the pushing lever against the wood to drive the nail After nailing once nailing will not be possible again until the trigger is released and pressed again CONTACT ACTUATION MECHANISM First press the pushing lever against the wood next pull the trigger to drive the nail First p...

Page 7: ...ailer output energy provided by the supply pressure and the nailing energy required for driving the nail flush Air pressure which exceeds the intersecting point between the nailer output energy and the required nailing energy for driving the nail allows the nail to be fully driven For example when driving a nail of 4 1 mm dia by 90 mm length 0 162 x 3 1 2 into a workpiece of hemlock spruce with th...

Page 8: ...shing lever first against a workpiece and then pulling the trigger and no nail is driven when pulling the trigger first and then pressing the pushing lever against a workpiece single actuation Please recommend the sequential fire parts set to the customers who want to use it Salespersons must instruct the customers to read the Handling Instructions attached to the sequential fire parts set and als...

Page 9: ...d Provided Direction change of exhaust air Handle grip Applicable nails Length Dia Tool not required Rubber 60 90 mm 2 3 8 3 1 2 2 9 4 1 mm 0 113 0 162 Tool not required Rubber 60 90 mm 2 3 8 3 1 2 Leather 60 90 mm 2 3 8 3 1 2 2 9 4 1 mm 0 113 0 162 With wrench 5 6 8 5 kgf cm2 80 120 psi 569 x 332 x 130 mm 22 13 32 x 13 1 16 x 5 1 8 2 4 ltr cycle 085 ft3 cycle 50 Top loading Aluminum 3 9 kg 8 6 lb...

Page 10: ...tomers who want to use it Refer to the leaflet attached together with the Instruction Manual for details 7 1 Handling Instructions Although every effort is made in each step of design manufacture and inspection to provide protection against safety hazards the dangers inherent in the use of any pneumatic tool cannot be completely eliminated Accordingly general precautions and suggestions for use of...

Page 11: ...sted in the Handling Instructions provided with each unit While there are no specific safety regulations there are related items in various general safety regulations with which the salespersons should be familiar in order to properly advise the customer Please check your national and or local regulations for applicable items Some applicable items are outlined below The U S A OSHA 1926 102 Eye and...

Page 12: ...Body Newly designed Control valve section Following parts were changed or added owing to the change of the construction selectable either the single actuation mechanism or the contact actuation mechanism Plunger A Newly designed common to the Model NT 65MA2 Valve piston B Newly designed common to the Model NT 65MA2 Trigger A Newly designed common to the Model NT 65MA2 Change knob switching device ...

Page 13: ...hangeable with those of the Model NR 90AC2 are described in detail 1 Output section Body 22 Part NR 90AC3 NR 90AC2 7 6 mm 299 dia hole Common to the Model NT 65MA2 7 mm 276 dia hole Trigger A 47 Part NR 90AC3 NR 90AC2 7 6 mm 299 dia hole Color Aluminum silver 7 mm 276 dia hole Valve Piston B 57 Color Black 24 C1 7 6 12 2 12 8 7 3 24 9 5 mm 374 dia Common to the Model NT 65MA2 Be careful not to mak...

Page 14: ...s in mounting plunger A because it is similar to that of the Model NR 65AK and other models but not interchangeable Groove 2 Control valve section continued No groove Common to the Model NT 65MA2 Spring C 49 Common to the Model NT 65MA2 12 6 34 6 34 12 The parts of the control valve section except the above are common to those of the Model NR 90AC2 ...

Page 15: ... the exhaust valve opens the compressed air in the head valve chamber is discharged into the atmosphere through the air passage 3 When the air pressure on the bottom surface of the Head Valve 10 overcomes the strength of the Head Valve Spring 8 the Head Valve 10 is pushed upward At this time the Head Valve 10 seals with the Exhaust Valve Rubber 7 blocking the passage to the exhaust vent 4 When the...

Page 16: ...lve Rubber 7 separate to open the exhaust vent 4 The compressed air above the Piston 19 is discharged into the atmosphere through the exhaust vent In this way the air pressure above the Piston 19 is reduced and the greater pressure of the air accumulated in the return air chamber pushes the Piston 19 upward 5 If the air pressure below the Piston 19 is higher than that of the atmosphere after the P...

Page 17: ...ston lower chamber and Valve Piston B 57 is forced upward The Piston 19 then returns fully upward Therefore unless Trigger A 47 is released after each nailing operation the structural mechanism prevents the next nailing operation Contact actuation mechanism Switching device downward position 1 Immediately after the first nail is driven the control valve should be as shown in Fig 8 2 Even when only...

Page 18: ... Check if nails one strip are fed smoothly into the nail injection port of the nose Use specified nails Magazine is loaded with abnormal nails bent nails large or small round head nails abnormal collation etc Nail or collating band clogs Collating band is deformed or torn Remove the abnormal nails and load the magazine with normal nails Nose Nail inlet groove of the nose is abnormal deformed burrs...

Page 19: ...ion method Remedy Pull the nail feeder backward and perform idle driving Check if the driver blade has returned Check if nails can be driven at 5 kgf cm2 While operating the nailer without nails check if the drivng operation is performed After operating the nailer without nails check if the driver blade is kept in the down position After making idle driving check if the driver blade is kept in the...

Page 20: ...mal worn or rough 3 Head of a nail driven into a workpiece protrudes from the wood surface Turn the adjuster to the lowest position and drive a nail Drive a nail into soft wood workpiece and check if the head protrudes from the wood surface Operate the nailer without nails and check if the driver blade is projected from the nose tip Disassemble the output section and check the piston ring O ring a...

Page 21: ...h control valve OFF With control valve ON Cylinder O ring B 9 of the Head Valve 10 is abnormal or its sliding surface a is worn deformed or flawed The Head Valve Rubber 12 is abnormal or the sealing surface b of the Cylinder 17 is worn or flawed The Exhaust Valve Rubber 7 is abnormal or the sliding surface c of the Head Valve 10 is worn or flawed A Exhaust port B Exhaust cover The Hex Socket Hd Bo...

Page 22: ...wed Air leakage point Possible cause With control valve OFF With control valve ON The Cylinder O ring 11 of the Body 22 or the groove is abnormal broken or flawed The Hex Socket Hd Bolt M8 x 30 64 is loose Piston Bumper A 24 is abnormal portion d is damaged deformed or cracked The Piston 19 is abnormal driver blade is deformed or seal surface is deformed The O ring I D 1 8 62 of Plunger A 61 is ab...

Page 23: ...damage the O rings and prevent dirt entry Oil required Hitachi pneumatic tool lubricant 1 oz 30 cc oil feeder Code No 877153 4 oz 120 cc oil feeder Code No 874042 1 quart 1 ltr can Code No 876212 If Gasket A 6 is damaged replace it and check that no air is leaking Be especially careful to prevent the entry of foreign particles into the control valve section Tightening torque for each part Bolt Tig...

Page 24: ... Exhaust Cover 5 Exhaust Valve Rubber 7 Bar of 4 to 5 mm dia Hammer Tools required Hex bar wrench 5 mm Hammer a Disassembly Remove the four Hex Socket Hd Bolt W Flange M6 x 35 4 with a hex bar wrench The entire Exhaust Cover 5 can now be removed from the Body 22 Remove the Hex Socket Hd Bolt M6 x 16 1 with a hex bar wrench The Plate 2 and the Top Cover 3 can now be removed As shown in Fig 9B inser...

Page 25: ...projection 2 Disassembly and reassembly of the Cylinder 17 Piston 19 Piston Bumpers A B 24 25 etc See Fig 13 a Disassembly Remove the Exhaust Cover 5 as described in item 1 Now the Cylinder 17 Cylinder Plate 13 Piston 19 Piston Bumpers A B 24 25 etc can be taken out b Reassembly Disassembly procedures should be followed in the reverse order Note the following points Apply designated grease to the ...

Page 26: ...d Reassembly of the Control Valve Section See Fig 14 Fig 15 Valve Piston B 57 Plunger Spring 60 Valve Bushing A 63 Plunger A 61 Head Valve O Ring I D 16 8 53 Body 22 Roll Pin D3 x 22 46 Retaining Ring E type for D6 Shaft 20 O Ring I D 1 8 62 Fig 14 Disassembly and reassembly of the control valve section Trigger A 47 Flat blade screwdriver Plunger A 61 Remove Pushing Lever B 33 O Ring I D 11 59 O R...

Page 27: ... careful not to damage Valve Piston B 57 Valve Bushings A 63 and B 54 etc Do not pull out the end of Plunger A 61 with the pliers 3 To take out Valve Bushing B 54 put a 1 5 to 3 mm 0 059 to 0 118 dia wire with its end hooked into the hole in the bushing and pull it out while being careful not to damage the internal surface of Valve Bushing B 54 as shown in Fig 17 Valve Bushing B 54 Hole Wire with ...

Page 28: ...ned with the roll pin hole in the Body 22 First insert the roll pin puller 3 mm dia into the roll pin hole Then upon confirming that the puller passes through the hole drive in the Roll Pin D3 x 22 46 If an attempt is made to drive the roll pin with force when the roll pin groove in Valve Bushing A 63 is not aligned with the roll pin hole in the Body 22 it will damage the periphery of Valve Bushin...

Page 29: ...ocedures should be followed in the reverse order Note the following points Apply designated grease to the O ring 1AS 60 26 and then install it Check that Nail Feeder B 75 moves smoothly Check that the Pushing Lever Stopper 74 is placed over Pushing Lever B 33 when Nail Feeder B 75 is at the front end See Fig 20 Pushing Lever Stopper 74 Nail Feeder B 75 Fig 20 Tools required Hex bar wrench 5 mm and...

Page 30: ...2 Magazine 79 Nail Feeder B 75 and the related parts See Fig 22 Tool required Hex bar wrench 5 mm a Disassembly Perform disassembly according to 10 4 to remove the entire magazine section The Connector 65 Nail Rail 66 Nail Feeder B 75 Ribbon Spring 77 and Needle Roller D4 x 20 78 can be removed from the front of the Magazine 79 Remove the three Hex Socket Hd Bolts W Flange M6 x 12 80 Then Handle A...

Page 31: ... Press the mounting surface of the Nail Stopper 81 against the Magazine 79 and slide it backward until the A portion fits into the concave portion of the Magazine Cover 70 then secure them with the bolt At this time mount the Sleeve 69 without fail Fig 22 Hook Nylon Nut M6 68 Sleeve 69 Nail Feeder B 75 Hex Socket Hd Bolt W Flange M6 x 12 80 Pushing Lever Stopper 74 Nail Stopper 81 Needle Roller D4...

Page 32: ... the Roll Pin D3 x 10 76 with the roll pin puller 3 mm 0 118 Then the Pushing Lever Stopper 74 can be removed from Nail Feeder B 75 b Reassembly Disassembly procedures should be followed in the reverse order Note the following points Insert the Pushing Lever Stopper 74 in Nail Feeder B 75 and secure with the Roll Pin D3 x 10 76 Insert the Roll Pin D4 x 40 72 into Nail Feeder B 75 Insert the Spring...

Page 33: ...with the Trigger A 47 pulled Recheck the tightening torque of each screw Check that the pushing lever ass y slides smoothly Check that the machine will not operate only by pulling Trigger A 47 Also check that the machine will not operate only by depressing Pushing Lever A 37 11 INSPECTION AND CONFIRMATION AFTER REASSEMBLY Check that the Pushing Lever Stopper 74 is not placed over Pushing Lever B 3...

Page 34: ...NR 90AC3 Work Flow Exhaust Cover Gasket A Exhaust Valve Rubber Head Valve Spring Cylinder O ring B Head Valve Cylinder O ring Head Valve Rubber 60 min 50 Nose Magazine Magazine Cover Nail Feeder A Nail Feeder B Ribbon Spring Pushing Lever B Spring Adjuster A Pushing Lever A General Assembly Cylinder Cylinder Plate O ring x 4 Piston Bumper A Piston Bumper B Body Piston O ring Adjustment Cylinder Bo...

Page 35: ...chi Power Tools 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 41 42 43 44 45 46 47 48 51 52 53 54 55 56 57 58 59 60 61 62 63 27 65 66 67 68 69 70 72 73 74 75 76 77 78 79 80 81 501 502 503 504 505 506 507 49 50 23 40 80 71 68 64 ...

Page 36: ...1 21 884 070 WARNING LABEL 1 22 884 140 BODY 1 23 NAME PLATE 1 24 883 670 PISTON BUMPER A 1 25 883 671 PISTON BUMPER B 1 26 956 996 O RING 1AS 60 1 27 881 969 NYLOCK BOLT W FLANGE M6X20 2 28 881 935 GUARD 1 29 883 674 COLLAR B 1 30 883 672 NOSE 1 31 949 864 ROLL PIN D3X22 10 PCS 1 32 883 691 SPRING 1 33 883 673 PUSHING LEVER B 1 34 881 974 ADJUSTER A 1 35 982 454 SPRING C 2 36 959 155 STEEL BALL D...

Page 37: ...78 888 O RING I D 1 8 1 63 880 671 VALVE BUSHING A 1 64 949 759 HEX SOCKET HD BOLT M8X30 10 PCS 4 65 883 690 CONNECTOR 1 66 883 682 NAIL RAIL 1 67 883 689 HANDLE ARM 1 68 963 837 NYLON NUT M6 3 69 883 499 SLEEVE 1 70 883 683 MAGAZINE COVER 1 71 883 685 NAIL FEEDER A 1 72 949 688 ROLL PIN D4X40 10 PCS 1 73 883 687 SPRING 1 74 883 688 PUSHING LEVER STOPPER 1 75 883 686 NAIL FEEDER B 1 76 949 776 ROL...

Page 38: ... 1 502 944 458 HEX BAR WRENCH 4MM 1 503 944 459 HEX BAR WRENCH 5MM 1 504 872 422 HEX BAR WRENCH 6MM 1 505 875 769 SAFETY GLASSES 1 506 884 146 CAUTION TAG 1 507 884 120 LEAFLET 1 601 877 153 PNEUMATIC TOOL LUBRICANT 30CC 1 602 874 042 PNEUMATIC TOOL LUBRICANT 120CC 1 603 876 212 PNEUMATIC TOOL LUBRICANT 1L 1 604 317 918 GREASE ATTOLUB NO 2 500G 1 605 878 898 CASE 1 606 881 768 GRIP TAPE A 1 607 88...

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