NPK GH7 User manual

HYDRAULIC HAMMER
OPERATORS MANUAL
GH SERIES HAMMERS
GH7 GH18
GH9 GH23
GH10 GH30
GH12 GH40
GH15 GH50
© Copyright 2014 NPK Construction Equipment, Inc. www.npkce.com H050-9630G GH7 - GH50
Hyd Ham Operators Manual 4-14
"Use Genuine NPK Parts”
7550 Independence Drive
Walton Hills, OH 44146-5541
Phone [phone]
Toll-free [phone]
Fax [phone]

NPK
- 1 -
CONTENTS
SAFETY ........................................................................................................................................................3
INTRODUCTION...........................................................................................................................................5
CARRIER MACHINE COMPATIBILITY........................................................................................................6
HAMMER SPECIFICATIONS.......................................................................................................................7
HAMMER SERIAL NUMBER LOCATION....................................................................................................8
HYDRAULIC INSTALLATION.......................................................................................................................9
PREVENTION OF CONTAMINATION...................................................................................................10
HYDRAULIC QUICK DISCONNECTS...................................................................................................11
MOUNTING INSTALLATION......................................................................................................................13
MOUNTING TO THE CARRIER.............................................................................................................14
REMOVAL FROM THE CARRIER.........................................................................................................14
LUBRICATION............................................................................................................................................15
GREASING PROCEDURE.....................................................................................................................15
CORRECT GREASE AND GREASE INTERVALS................................................................................16
AUTOLUBE SYSTEMS..........................................................................................................................18
AUTOLUBE GREASE LINE PRE-FILLING............................................................................................19
LUBRICANT TERMS AND DEFINITIONS.............................................................................................22
START-UP OPERATION............................................................................................................................24
HAMMERS THAT ARE NEW, REBUILT, OR HAVE BEEN INACTIVE.................................................24
BEFORE STARTING THE HAMMER ....................................................................................................25
DAILY START-UP PROCEDURE..........................................................................................................25
OPERATION...............................................................................................................................................26
SAFE OPERATING INSTRUCTIONS....................................................................................................26
OPERATING TECHNIQUES & PRECAUTIONS...................................................................................27
IMPACT ENERGY TRANSMISSION THROUGH TOOLS.........................................................................32
IMPACT STRESS WAVES AT THE END OF THE TOOL.....................................................................33
ROUTINE INSPECTION AND MAINTENANCE.........................................................................................34
WEEKLY INSPECTION..............................................................................................................................35
TYPES AND APPLICATIONS OF TOOL....................................................................................................36
STANDARD TOOLS...............................................................................................................................36
TOOL IDENTIFICATION.............................................................................................................................37
CHANGING THE TOOL .........................................................................................................................38
MAXIMUM TOOL TO TOOL BUSHING CLEARANCE..........................................................................39
CHISEL TOOL RESHARPENING..........................................................................................................41
TOOLS........................................................................................................................................................42
STANDARD LENGTH FOR NPK TOOLS..............................................................................................42
TOOL RETAINING PIN INSPECTION...................................................................................................43
TOOL INSPECTION...............................................................................................................................44

NPK
- 2 -
CONTENTS
TOOL WARRANTY.....................................................................................................................................45
TOOL BREAKAGE......................................................................................................................................47
TOOL BREAKAGE DUE TO EXCESSIVE BENDING MOMENT ..........................................................47
CHARACTERISTICS OF THE BROKEN SECTION..............................................................................47
TOOL BREAKAGE DUE TO EXCESSIVE WEAR OF THE TOOL HOLDER BUSHINGS....................48
CHIPPING IN RETAINING PIN SLOT....................................................................................................50
DEFORMATION OF THE RETAINING PIN SLOT SIDES.....................................................................50
DEFORMATION OF THE TOOL TIP .....................................................................................................51
CHIPPING OF A MOIL POINT TOOL TIP..............................................................................................52
CHIPPING OF A CHISEL TOOL TIP .....................................................................................................52
TEMPERATURE RELATED TOOL PROBLEMS...................................................................................53
TOOL BREAKAGE DUE TO CORROSION...........................................................................................54
TOOL BREAKAGE DUE TO DEFECTIVE MATERIAL..........................................................................54
TORQUE VALUES FOR HAMMER FASTENERS.....................................................................................55
HAMMER BRACKET – GH7 THROUGH GH50 ....................................................................................56
GAS CHARGE............................................................................................................................................57
NITROGEN GAS PRESSURE ...............................................................................................................57
GAS CHARGING KIT.............................................................................................................................57
CHECKING THE GAS PRESSURE.......................................................................................................58
CHARGING THE HAMMER...................................................................................................................60
DISCHARGING THE GAS PRESSURE.................................................................................................62
WARRANTY REGISTRATION FOR NEW UNITS .....................................................................................63
STORAGE OF HYDRAULIC HAMMER......................................................................................................64
WARRANTY STATEMENTS ......................................................................................................................65
NOTES AND RECORDS............................................................................................................................69


NPK
- 3 -
SAFETY
Safety notices in NPK Instruction Manuals follow ISO and ANSI standards for
safety warnings:
DANGER (red) notices indicate an imminently hazardous situation
which, if not avoided, will result in death or serious injury.
WARNING (orange) notices indicate a potentially hazardous situation
which, if not avoided, could result in death or serious injury.
CAUTION (yellow) notices indicate a potentially hazardous situation,
which, if not avoided, may result in minor or moderate injury.
ATTENTION (blue) notices in NPK Instruction Manuals are an NPK
standard to alert the reader to situations which, if not avoided, could
result in equipment damage.
WARNING and BASIC OPERATING INSTRUCTIONS decals are included with each
NPK hammer and installation kit. Decals must be installed in the cab, visible to the
operator while operating the hammer.
STAY CLEAR, PRESSURE VESSEL, GAS PRESSURE and TOOL SHARPENING
decals are installed on all NPK hammer models. Keep them clean and visible. NPK will
provide decals free of charge as needed.
1. Operator and Service personnel must read and understand the NPK INSTRUCTION
MANUALS to prevent serious or fatal injury.
2. FLYING DEBRIS CAN CAUSE SERIOUS OR FATAL INJURY.
Keep personnel and bystanders clear of
hammer while in operation.
Do not operate HAMMER without an impact
resistant guard between HAMMER and
operator. NPK recommends LEXANor
equivalent material, or steel mesh.
Some carrier manufacturers offer demolition
guards for their machine. Check with the
carrier manufacturer for availability. If not
available, please call NPK.
3. Do not hardface or sharpen the tool point with
a cutting torch. Excessive heat from torching
or welding can cause embrittlement, breakage,
and flying pieces. Resharpen by milling or
grinding only, using sufficient coolant.
Warning Decal for Cab Installation

NPK
- 4 -
SAFETY
4. Fully extend the tool while charging the HAMMER with nitrogen gas. Be sure that
the retaining pin is installed. STAY CLEAR OF TOOL POINT WHILE CHARGING.
5. Do not disassemble a HAMMER before discharging the hammer gas pre-charge.
6. USE NITROGEN GAS ONLY! Store and handle nitrogen tanks per OSHA
regulations.
7. Avoid high pressure fluids. Escaping fluid under pressure can penetrate the skin
causing serious injury. Relieve pressure before disconnecting hydraulic or other
lines.
8. Operate HAMMER from operator’s seat only.
9. Match HAMMER size to carrier according to NPK recommendations. The carrier
must be stable during hammer operation and during transport.
See CARRIER MACHINE COMPATIBILITY section of the NPK Service Manual.
10. Do not make any alterations to the TOOL without authorization from NPK
Engineering.
11. Use proper lifting equipment and tools when handling or servicing the HAMMER.
12. Wear ear protection and safety glasses when operating the hammer. Consult
OSHA/MSHA regulations when applicable.
13. Beware of flying metal pieces when driving Boom Pins.
14. Do not alter the HAMMER without authorization from NPK Engineering!
15. Use only genuine NPK replacement parts. NPK specifically disclaims any
responsibility for any damage or injury that results from the use of any tool or parts
not sold or approved by NPK.
For further safety information, consult the AEM Hydraulic Mounted Breakers Safety
Manual, AEM form MB-140 (NPK P/N H050-9600), which is furnished with every NPK
hammer. To request an additional copy, please contact NPK at 800-225-4379 or
Internet at www.npkce.com.

NPK
- 5 -
INTRODUCTION
NPK is a leading manufacturer of boom mounted HYDRAULIC HAMMERS, and has the
most complete product line available anywhere. The success of NPK is due to our
commitment to quality, dependability and long life. The HYDRAULIC HAMMER has
many unique designed features and it is a company philosophy that the NPK
HYDRAULIC HAMMER can be brought to "like new” condition long after competitive
products are scrapped. You can feel confident that you have purchased the best value
available.
This comprehensive manual contains instructions for operating and maintaining NPK
HYDRAULIC HAMMERS. This manual includes helpful information for obtaining the full
potential and efficiency from NPK HYDRAULIC HAMMERS. Please read this manual
thoroughly to understand the NPK HAMMER and its operating principles before using it.
For additional information or help with any problem encountered, please contact your
NPK authorized dealer.
Whenever repair or replacement of component parts is required, only NPK parts should
be used. NPK is not responsible for failures resulting from substitution of parts not sold
or approved by NPK.
This manual will also assist NPK Dealers and Customers to obtain the longest possible
life from the NPK Demolition Tools.
Customers can use this manual to take corrective action when tool breakage occurs.
Dealers can use this manual to determine if tool breakage can be claimed under
warranty.
Refer to the NPK Demolition Tool Warranty statement found later in this manual for the
specifics of the warranty coverage.

NPK
- 6 -
CARRIER MACHINE COMPATIBILITY
These carrier weight ranges are intended as a guideline only. Other factors, such as
stick length, counterweights, undercarriage, etc., must be taken into consideration.
Mounting a HAMMER that is too heavy for the carrier machine can be dangerous and
can damage the carrier. Verify carrier stability with HAMMER before transport or
operation.
Mounting a HAMMER that is too small for the carrier machine can damage the
HAMMER, cause tool breakage and void Warranties. Please consult the NPK Sales
Department for specific detailed information.
CARRIER WEIGHT lbs. (kg)
HAMMER RECOMMENDED CARRIER WEIGHT RANGE
MODEL (lb) (kg)
GH7 28,000 - 42,000 12,700 - 19,000
GH9 40,000 - 56,000 18,000 - 25,000
GH10 46,000 - 66,000 20,000 - 30,000
GH12 56,000 - 86,000 25,000 - 38,000
GH15 66,000 - 100,000 30,000 - 45,000
GH18 70,000 - 114,000 32,000 - 52,000
GH23 100,000 - 150,000 45,000 - 68,000
GH30 100,000 - 186,000 45,000 - 84,000
GH40 160,000 - 260,000 72,000 - 117,000
GH50 (1) 240,000 + (1) 108,000 +
*Specifications subject to change without notice.
(1) Contact the NPK Sales Department for carrier range.

NPK
- 7 -
HAMMER SPECIFICATIONS
HAMMER
MODEL
IMPACT
ENERGY
CLASS
FREQUENCY WORKING
WEIGHT
TOOL
DIA WORKING
LENGTH
ft lb bpm lbs (Kg) in (mm) in (mm)
GH7 2500 400 - 750 2900 (1320) 4.6 (116) 23 (583)
GH9 3000 500 - 670 3600 (1635) 5.0 (126) 24 (608)
GH10 4000 400 - 550 4200 (1900) 5.4 (136) 24.5 (620)
GH12 5500 380 - 480 5650 (2565) 5.7 (146) 25.5 (650)
GH15 8000 320 - 400 6800 (3085) 6.1 (156) 27 (690)
GH18 12000 300 - 400 7800 (3540) 6.5 (165) 29 (740)
GH23 13500 300 - 400 9240 (4190) 6.9 (174) 34.6 (880)
GH30 15000 310 - 390 13500 (6125) 7.2 (184) 32 (813)
GH40 17000 240 - 330 17000 (7710) 8.0 (204) 35.4 (899)
GH50 20000 210 - 280 24910 (11300) 8.4 (214) 39.7 (1008)
HAMMER
MODEL
OIL FLOW HYDRAULIC OPERATING
PRESSURE 1
CIRCUIT
RELIEF
minimum 2
GAS CHARGE
PRESSURE 5
Cold 3Hot
4
gpm (L/min) psi (bar) psi (bar) psi (bar) psi (bar)
GH7 26 - 48 (100 - 180) 2600 (180) 3100 (215) 350 (24) 405 (28)
GH9 40 - 53 (150 - 200) 2600 (180) 3100 (215) 365 (25) 420 (29)
GH10 44 - 55 (165 - 210) 2600 (180) 3100 (215) 365 (25) 420 (29)
GH12 45 - 58 (170 - 220) 2650 (183) 3150 (218) 365 (25) 420 (29)
GH15 53 - 66 (200 - 250) 2600 (180) 3100 (215) 365 (25) 420 (29)
GH18 58 - 77 (220 - 290) 2500 (172) 3000 (207) 365 (25) 420 (29)
GH23 66 - 85 (250 - 320) 2600 (180) 3100 (215) 390 (27) 450 (31)
GH30 74 - 92 (280 - 350) 2600 (180) 3100 (215) 390 (27) 450 (31)
GH40 79 - 106 (300 - 400) 2600 (180) 3100 (215) 390 (27) 450 (31)
GH50 92 - 119 (350 - 450) 2600 (180) 3100 (215) 390 (27) 450 (31)
*Specifications subject to change without notice.
NOTES:
1. Hydraulic operating pressure maximum is inlet pressure at the hammer with the oil at
operating temperature and with the gas charge set at the hot operating pressure.
See CHECKING THE HYDRAULIC PRESSURES section in Service Manual.
2. Circuit relief pressure is at least 500 psi (35 bar) above hammer operating pressure.
3. Cold gas charge is the initial set with the hammer at ambient temperature.
4. Hot gas charge is checked after 1 to 2 hours of running and with a system oil temperature of
140° to 180°F (60° to 80°C). This is the preferred check.
5. Pressures listed are maximum. Use tolerance of minus 25 psi (2 bar).

NPK
- 8 -
HAMMER SERIAL NUMBER LOCATION
NPK HAMMER MODELS GH7 through GH50
The serial number location (sn1) is right of center on the body above the Autolube port.

NPK
- 9 -
HYDRAULIC INSTALLATION
NPK INSTALLATION KITS are available for virtually all compatible backhoe loaders,
excavators, and skid steers. Complete parts and instructions for the hydraulic
installation of the NPK HYDRAULIC HAMMER including valving and/or controls, hoses
and fittings, accumulators, boom and stick tubing, and clamps are provided.
HAMMER LINES
Typically, the pressure line is arranged on the left side of the boom and the return line
on the right side. Flow to the hammer is controlled from an auxiliary valve on the carrier
or from an NPK supplied valve. Hydraulic oil is routed back to the tank through the
carrier’s oil cooler and filter.
HAMMER CONTROL VALVE
NPK uses two general types of control systems, depending upon the carrier model:
1. CONTROL SYSTEM USING CARRIER AUXILIARY OR SPARE VALVE SECTION.
This type of installation utilizes an existing carrier valve. Any additional parts, such
as a mechanical linkage, hydraulic pilot control valve, flow control valves, etc., are
furnished in the NPK HYDRAULIC INSTALLATION KIT. Special hydraulic relief
cartridges are not required. The NPK HYDRAULIC HAMMER operating pressure is
self-regulating.
2. CONTROL SYSTEM USING THE NPK MULTIVALVE.
For carriers not equipped with a suitable auxiliary or spare valve section, the NPK
HYDRAULIC INSTALLATION KIT includes a solenoid operated, priority flow control
valve to operate the NPK HYDRAULIC HAMMER. The NPK MULTIVALVE is
specifically designed for the operation of boom mounted attachments.