Hitachi DH 45SA Manual

POWER TOOLS
TECHNICAL DATA
AND
SERVICE MANUAL
HAMMER DRILL
DH 45SA
SPECIFICATIONS AND PARTS ARE SUBJECT TO CHANGE FOR IMPROVEMENT
LIST No. E457 Apr. 2000
D
MODELS
DH 45SA

CONTENTS
Page[ Business Section ]
1. PRODUCT NAME
•••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• 1
2. MARKETING OBJECTIVE •••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• 1
3. APPLICATIONS •••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• 1
4. SELLING POINTS ••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• 2
4-1. Selling Point Descriptions ••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• 3
5. SPECIFICATIONS ••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• 4
5-1. Specifications •••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• 4
5-2. Optional Accessories ••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• 5
6. COMPARISONS WITH SIMILAR PRODUCTS •••••••••••••••••••••••••••••••••••••• •••••••••••••••••••••••••••••••••••••• 10
6-1. Specification Comparisons ••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• 10
6-2. Drilling Speed Comparison•••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• 11
6-3. Chiseling Performance ••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• 12
7. PRECAUTIONS IN SALES PROMOTION ••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• 13
7-1. Handling Instructions ••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• 13
8. REFERENCES •••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• 13
8-1. Grease Replacement Procedures ••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• 13
8-2. O-Ring Replacement •••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• 13
8-3. Structure of the DH 45SA Hammer Drill ••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• 14
[ Service Section ]
9. PRECAUTIONS IN DISASSEMBLYAND REASSEMBLY••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• 19
9-1. Disassembly •••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• 19
9-2. Reassembly •••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• 20
9-3. Screw Lock TB 1401 ••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• 22
9-4. Tightening Torque ••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• 22
9-5. Wiring Diagrams ••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• 23
9-6. Insulation Tests •••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• 23
9-7. No-load Current Values ••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• 23
10. STANDARD REPAIR TIME (UNIT) SCHEDULES •••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• 24
[ Appendix ]
Assembly Diagram for DH 45SA••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• 25
Notice for use
Specifications and parts are subject to change for improvement.
Refer to Hitachi Power Tool Technical News for further information.

--- 1 ---
1. PRODUCT NAME
Hitachi Hammer Drill, Model DH 45SA
2. MARKETING OBJECTIVE
There are four shank types in the 40 --- 50 mm market.
(1) Hexagon (13 mm ), (2) Hexagon (19 mm-Kango-), (3) SDS max, (4) Spline
The market tendency shows growth of the SDS max shank share, however, the hexagon (13 mm) shank retains
its No. 1 share in many markets because of economical accessory prices and compatibility with customer's
existing tools and accessories. Recently, demand for bigger dia. hole drilling is increasing year by year for
computer cable wiring and anchoring for earthquake-proof reinforcement work.
To meet market demand for a powerful, larger capacity Hammer Drill with hexagon (13 mm) shank, the Model
DH 45SA was developed as an advanced version of Model DH 40SA/YB.
The key features are as follows:
High performance, fast drilling speed: 80 % faster (at maximum) than DH 40SA/YB
Less fatigue, comfortable operation using the soft-grip & shock-absorbing handle
Other features (grease-packed lubrication, ergonomic exterior design)
3. APPLICATIONS
Concrete drilling
Drilling anchor bolt holes
Crushing, chiseling, grooving, edging, cutting, stripping, compacting/tamping and roughing concrete surfaces
[Applicable examples]
Air conditioning ••••••••••••••••••••••••••••••••Installation of air conditioners and water coolers
Piping and wiring •••••••••••••••••••••••••••••Electric, gas and water supply work
Electric fixtures ••••••••••••••••••••••••••••••• Installation of electrical and lighting fixtures
Sanitary facilities••••••••••••••••••••••••••••••Sanitary plumbing
Interior finishing •••••••••••••••••••••••••••••••Installation of seats, display counters, ducts and interior decoration
Other building, construction and repair work
2
1

--- 2 ---
4. SELLING POINTS
Soft-touch handle and side handle
Double-insulation for safer operation
without grounding
Maintenance-free sealed
grease design
Easy-to-use rotary type bit
retainer for quick bit changes
Fig. 1
Vibration-isolating handle provided with
vibration-isolating rubbers reduces operator fatigue
Faster drilling speed and higher efficiency thanks to the powerful motor and
greater striking energy
(About 1.4 times faster than the Model DH 42)
(About 1.8 times faster than the Models DH 40SA/YB)

--- 3 ---
4-1. Selling Point Descriptions
4-1-1. Faster drilling speed
The drilling speed is 40 % faster than that of the Model DH 42, as the Model DH 45SA has greater striking energy
owing to the powerful motor and the total optimization of the rotation speed, striking frequency and the weight of
the striker.
4-1-2. Vibration-isolating handle reduces operator fatigue
The two vibration-isolating rubbers provided between the handle and the crank case, and also between the handle
and the housing efficiently absorb the vibration transmitted from the tool main body to minimize transmission of
vibration to the operator's arms.
4-1-3. Soft-touch handle and side handle
The double-layer molded handle and side handle consist of a plastic resin base covered with a soft plastic layer to
ensure a soft touch and easy grip of the handles.
4-1-4. Easy-to-use tool holder
The easy-to-grip tool holder allows the tool to be attached or removed simply by turning the grip.
4-1-5. Needle-pin type slip clutch
The Model DH 45SA is equipped with a needle-pin type slip clutch to ensure higher accuracy slip torque and
enhanced safety.
Fig. 2
Handle side
Vibration-isolating rubber
Vibration-isolating rubber

--- 4 ---
Material
Housing ••• Glassfiber reinforced polyamide resin (green)
Handle
Handle cover
Crank case cover ••• Glassfiber reinforced polyamide resin (black, gray)
Type of handle
Drill bit (max. dia.): 45 mm (1-3/4"), core bit (max.dia.): 120 mm (4-3/4")
5. SPECIFICATIONS
5-1. Specifications
Capacity
Power source
Voltage, current, input
Type of switch
Enclosure
Dimensions
Weight
Packaging
Standard accessories
Net*
Gross
AC single phase 50 Hz or 60 Hz
300/min.
250/min.
Trigger switch
D-type handle and side handle
10.3 kg (22.7 lbs.)
15.2 kg (33.4 lbs.)
Corrugated cardboard box
Plastic case •••••••••••••••••••••••••••••••••••••• 1
Side handle ••••••••••••••••••••••••••••••••••••••• 1
Hex. bar wrench 5 mm ••••••••••••••••••••••• 1
Hex. bar wrench 6 mm ••••••••••••••••••••••• 1
Hex. bar wrench 8 mm ••••••••••••••••••••••• 1
Stopper •••••••••••••••••••••••••••••••••••••••••••• 1
Grease (A) •••••••••••••••••••••••••••••••••••••••• 1
Dust cap ••••••••••••••••••••••••••••••••••••••••••• 1
Voltage (V)
Current (A)
Input (W)
110 115 127 220 230 240
13.4 12.8 11.6 6.6 6.4 6.2
1400
* Net weight excludes cord and side handle.
Rotation
speed No-load
Full-load
Type of motor AC single phase commutator motor
Full-load blow 2,500/min.
Insulation structure Double insulation
Plastic case color Off-black green
478 mm x 293 mm x 120 mm (Length x Height x Width)
(18-13/16" x 11-9/16" x 4-3/4")

--- 5 ---
5-2. Optional Accessories
1. Drilling work for through-holes (rotation + striking)
(1) Drill bit (hexagon shaft)
+
+
Code No.
985721
---
985724
---
985727
985730
985733
---
985736
---
985739
313322
280 (11")
Overall length (mm)
Outer diameter (mm)
16 (5/8")
18 (11/16")
19 (3/4")
20 (25/32")
22 (7/8")
25 (31/32")
28 (1-7/64")
30 (1-3/16")
32 (1-1/4")
35 (1-3/8")
38 (1-1/2")
40 (1-9/16")
Code No.
985720
---
985723
---
985726
985729
985732
---
985735
---
985738
---
400 (15-3/4") Code No.
991330
991331
991332
991333
991335
991336
991337
991338
991339
991340
991341
---
550 (21-5/8")
Code No.
985722
---
985725
991334
985728
985731
985734
---
985737
---
985740
---
505 (19-7/8")
2. Drilling work for anchor holes (rotation + striking)
+
(1) Drill bit (taper shank) (2) Taper shank adapter
(3) Cotter
(3) Cotter
Outer diameter (mm) Code No.
11 (7/16") 944460
12.3 (15/32") 944461
12.7 (1/2") 993038
14.3 (9/16") 944462
14.5 (9/16") 944500
17.5 (11/16") 944463
21.5 (27/32") 944464
(1) Drill bit (taper shank) (2) Taper shank adapter
Taper dimension Code No.
Morse taper No.1
Morse taper No.2
985750
985751
944477
Code No.

--- 6 ---
Outer diameter (in.)
54 mm (2-1/8")
64 mm (2-17/32")
79 mm (3-1/8")
94 mm (3-11/16")
105 mm (4-1/8")
120 mm (4-3/4")
Code No.
955155
956002
955157
956004
955159
956006
A-taper
B-taper
9.7 mm (3/8") x 1/20 Taper (A) 985754
12.9 mm (1/2") x 1/20 Taper (B) 985755
Taper shank adapters forA-taper or
B-taper shanks are provided as optional
accessories. Taper shank drill bits are
not provided.
For Australia
K-taper shank adapter 992813
+
+
A ratio shank adapter is provided as an optional accessory, but corresponding drill bits are not provided.
(1) Drill bit (ratio shank) (2) Ratio shank adapter Code No. 985761
3. Boring work for large-dia. holes (rotation + striking)
++++
(2) Guide plate
Core bits with outer diameter of 32, 35, 38, 45, 54, 64, 79, 105, 120 mm (1-1/4", 1-3/8", 1-1/2", 1-25/32",
2-1/8", 2-17/32", 3-1/8", 3-11/16", 4-1/8", 4-3/4")
[Guide plate is not used with core bits with outer diameter of 25 mm (31/32") and 29 mm (1-5/32")]
(3) Core bit
Outer diameter (in.)
25 mm (31/32")
29 mm (1-5/32")
32 mm (1-1/4")
35 mm (1-3/8")
38 mm (1-1/2")
45 mm (1-25/32")
Code No.
955994
955995
955996
955998
956000
955154
(4) Core bit shank
(1) Center pin
Code No. 956009 for core bits with outer diameter of 32, 35 mm (1-1/4", 1-3/8")
Code No. 955165 for core bits with outer diameter of 38, 45, 54, 64, 79, 94, 105, 120 mm (1-1/2", 1-25/32",
2-1/8", 2-17/32", 3-1/8", 3-11/16", 4-1/8", 4-3/4")
[Center pin is not used with core bits of 25 mm (31/32") and 29 mm (1-5/32")]
Code No. 956008 for core bits with outer diameter of 25, 29, 32 and 35 mm (31/32", 1-5/32", 1-1/4" and 1-3/8")
Code No. 955163 for core bits with outer diameter of 38, 45, 54, 64, 79, 94, 105, 120 mm (1-1/2", 1-25/32",
1-1/8", 1-17/32", 3-11/16", 4-1/8", 4-3/4")
(1) Center pin (2) Guide plate (3) Core bit (4) Core bit shank

--- 7 ---
(1) Anchor adapter (for impact)
Anchor size: W3/8 (No. 30), W1/2 (No. 40)
W5/8 (No.50)
(1) Anchor adapter (for rotation + striking)
Anchor size W1/4 (No. 20), W5/16 (No. 25), W3/8 (No. 30),
W1/2 (No. 40), W5/8 (No. 50)
(2) Drift key (Code No. 944574)
5. Anchor work for self-drilling anchors (striking)
(5) Core bit for efficient drilling
Center pin (C) Core bit (with guide plate) Core bit shank
Code No.
Code No. Outer diameter (in.) Code No.
4. Anchor work for self-drilling anchors (rotation + striking)
65 mm (2-9/16")
80 mm (3-5/32")
90 mm (3-1/2")
100 mm (3-15/16")
105 mm (4-1/8")
992814
992815
992816
992817
992818
903901 992819
+
+
+
W 1/4 (No. 20)
W 5/16 (No. 25)
W 3/8 (No. 30)
W 1/2 (No. 40)
W 5/8 (No. 50)
(1) Anchor size Code No.
985756
985757
985758
985759
985760
+
+
++
W 3/8 (No. 30)
W 1/2 (No. 40)
W 5/8 (No. 50)
(1) Anchor size Code No.
981929
981930
981931
(2) Turning handle (Code No. 944573)
(3) Drift key (Code No. 944574)

--- 8 ---
6. Demolition work (striking)
(1) Bull point
Overall length: 280 mm (11"), 450 mm (17-3/4")
280 mm
450 mm
Overall length Code No.
981922
981923
+
7. Grooving and edging work (striking)
(1) Cold chisel
Overall length: 280 mm (11"), 450 mm (17-3/4")
+
280 mm
450 mm
Overall length Code No.
981925
981926
8. Cutting and stripping work (asphalt cutting, etc.) (striking)
+
(1) Cutter
9. Digging work (substitute pick-ax) (striking)
280 mm (11")
Overall length Code No.
98192445 mm (2")
Width
+
(1) Scoop
405 mm (16")
Overall length Code No.
956126

--- 9 ---
10. Roughing surface work (striking)
(1) Bushing tool (2) Shank
++
250 mm (10")
Overall length Code No.
955186
Code No. 955183
11. Tamping work (striking)
++
(1) Rammer (2) Shank
250 mm (10")
Overall length Code No.
955186
Code No. 955181
O.D. 140 mm (5-33/64")
12. Syringe (for chip removal)
Code No. 944575
13. Impact drill grease
Code No. 980927
500 g Can Code No. 308471
70 g Tube Code No. 981840 30 g Tube
Note: Code numbers listed above are subject to change without notice. Please refer to periodic Technical
News Bulletins for updates.

--- 10 ---
Overall length (mm)
6. COMPARISONS WITH SIMILAR PRODUCTS
6-1. Specification Comparisons
Maker
Model
Item
Capacity Drill bit dia. (mm)
Input (W)
No-load (/min.)
Full-load blow (/min.)
Dimensions
Full-load vibration level (dB)
Insulation structure
Height (mm)
*Weight excludes cord and side handle.
Core bit dia. (mm)
Full-load (/min.)
Rotation
speed
Weight listed on the catalog (kg)*
Actual weight (kg)*
No-load sound pressure level (dB/A)
415 (16-11/32")
255 (10-1/32")
102 (4-1/32")
425 (16-3/4")
252 (9-15/16")
103 (4-1/16")
480 (18-29/32")
260 (10-1/4")
115 (4-17/32")
478 (18-13/16")
293 (11-9/16")
120 (4-3/4")
10.3 (22.7 lbs.) 8 (17.6 lbs.) 6.9 (15.2 lbs.) 8 (17.6 lbs.)
9.8 (21.6 lbs.) 8 (17.6 lbs.) 6.5 (14.3 lbs.) 8 (17.6 lbs.)
2500 3100 2800 2750
Double insulation Single insulation Double insulation Double insulation
121 119 118 118
87 88 87 88
1400 1140 950 1150
45 (1-3/4")
120 (4-3/4") 40 (1-9/16")
120 (4-3/4") 40 (1-9/16")
105 (4-1/8") 38 (1-1/2") 120 (4-3/4")
300
250
370
290
360
300
360
260
HITACHI
DH 45SA HITACHI
DH 42 HITACHI DH 40SA C
Width (mm)

--- 11 ---
6-2. Drilling Speed Comparison
Drilling speed varies considerably depending on the work conditions. Use the factory test results shown in Fig. 3
as a reference, for comparison purposes only.
Fig.3
[Test conditions]
Posture : Downward drilling
Pressure force : 98 N (10 kgf)
Test material : Concrete panel with a compression strength of 23.5 x 106N/m2(240 kgf/cm2)
Drill bit size : 13 mm hexagon shank bit
*: Note that the data marked with asterisk is the test result using a drill bit which is beyond the tool's rated
capacity. Use the above data as a reference, for comparison purposes only.
16
22
25
28
32
38
40
HITACHI
HITACHI
HITACHI
C
HITACHI
HITACHI
HITACHI
C
HITACHI
HITACHI
HITACHI
C
HITACHI
HITACHI
HITACHI
C
HITACHI
HITACHI
HITACHI
C
HITACHI
HITACHI
HITACHI
C
HITACHI
HITACHI
HITACHI
C
DH 45SA
DH 42
DH 40SA
C
DH 45SA
DH 42
DH 40SA
C
DH 45SA
DH 42
DH 40SA
C
DH 45SA
DH 42
DH 40SA
C
DH 45SA
DH 42
DH 40SA
C
DH 45SA
DH 42
DH 40SA
C
DH 45SA
DH 42
DH 40SA
C
Drill bit dia.
(mm) Maker Model Drilling speed (mm/min.)
0500
400
300
200
100
170
120
170
220
220
150
210
300
260
115
80
60 80
110
80
60 75*
270
240 300
350
240
190
410
410
340 410
540

--- 12 ---
[Test conditions]
Posture : Downward chiseling
Test material : Concrete panel with a compression strength of 23.5 x 106N/m2(240 kgf/cm2)
Bull point size : Bull point of 280 mm
Fig. 4
6-3. Chiseling Performance
Chiseling performance varies considerably depending on the work conditions. Use these factory test results
shown in Fig. 4 as a reference, for comparison purposes only.
DH 42
DH 45SA
DH 40SA
C
160
100
70
70
50 100 150
0
Voltage
230 V
Chiseling quantity (kg/30 min.)
Chiseling quantity in 30 min.

--- 13 ---
7. PRECAUTIONS IN SALES PROMOTION
In the interest of promoting the safest and most efficient use of the Model DH 45SAHammer Drill by all of our
customers, it is very important that at the time of sale the salesperson carefully ensures that the buyer seriously
recognizes the importance of the contents of the Handling Instructions, and fully understands the meaning of the
precautions listed on the Caution Plate attached to each tool.
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 electric tool cannot be completely eliminated. Accordingly,
general precautions and suggestions for the use of electric power tools, and specific precautions and suggestions
for the use of the Hammer Drill are listed in the Handling Instructions to enhance the safe, efficient use of the tool
by the customer. Salespersons must be thoroughly familiar with the contents of the Handling Instructions to be
able to offer appropriate guidance to the customer during sales promotion.
8. REFERENCES
8-1. Grease Replacement Procedures
The electro-pneumatic hammering section and gear change section each use different kinds of grease. It is not
necessary to replenish the grease unless the tool is disassembled for repair or there is grease leakage due to a
damaged seal.
A special grease is used for the hammering section. To change the grease in the hammering section (cylinder
case and crank case), carefully wipe the old grease off the parts, and re-lube with 30 g in the cylinder case and
75 g in the crank case (on the connecting rod side). Take care not to overfill with grease as an excessive amount
of grease can cause hammering failure.
The gear change section (in the gear cover) uses grease No. 29 for power tools. Apply 40 g to the gear cover and
the gear portion in the crank case, and 20 g between the washer (A) of the slip clutch and the crank case. Do not
use the special grease used for the hammering section, or it will leak to the motor parts resulting in failure of the
tool.
8-2. O-Ring Replacement
The O-ring (attached to the striker and piston) plays an important role to ensure air tightness. Despite its
prolonged service life due to a special rubber material, it will inevitably wear out. Early replacement, preferably
once every six months, is recommended.

--- 14 ---
8-3. Structure of the DH 45SA Hammer Drill
Cylinder
Key
Striker
Air chamber Bevel
gear Piston
Connecting rod
Crank shaft
First gear
Second hammer
Spline connection
O-ring
Second gear
Bevel pinion
Armature
Fig. 5
Rotation transmission
Rotation transmission is described with reference to Fig. 5. The gear arrangement of the DH 45SA has the
armature shaft positioned between the crank shaft and the bevel pinion shaft. Rotation of the armature shaft is
transmitted to the second gear through the first gear of the crank shaft and the second pinion. Then the
rotation is transmitted from the second gear through the slip mechanism disposed between the second gear
and the bevel pinion shaft to turn the bevel gear. The latter is keyed to the cylinder to rotate together. Cylinder
rotation is transmitted through the spline connection to the second hammer. Rotation is then transmitted to the
drill bit which is fitted into the hexagonal hole of the second hammer.
Hammering action
Armature rotation is transmitted to the crank and the connecting rod to reciprocally move the piston within the
cylinder. Air pressure developed between the piston and the striker changes as the piston moves. This causes
the striker to continuously hit the end face of the second hammer. Since the striker is moved under air
pressure, a certain air cushioning effect absorbs the striking shock.
If there is any leakage from the air chamber, the air cushioning effect becomes insufficient, resulting in an
incomplete shock absorbing effect. This is why the O-rings (attached to the striker and piston) for air tightness
are so important.
Second pinion

--- 15 ---
Needle pin Spring (C)
Key
Gear holder
Elongated
groove of the
gear holder
Arrangement against idle hammering
The DH 45SA is provided with an arrangement against idle hammering similar to that of the previous
DH 40SA. When the drill bit or bull point is moved off the concrete material, the second hammer is shifted
forward as indicated in Fig. 6 to change the striking position of the striker. This causes the air hole to open so
that air pressure within the air chamber no longer changes even with movement of the piston, bringing the
hammering action to a stop.
Air chamber
Second hammer
Striker
Air hole
Travel distance of the second
hammer and the striker
Fig. 6
Slip mechanism
The slip mechanism structure is described below with reference to Fig. 7. The bevel pinion and the gear holder
are coupled together by the key and press-fitting. Spring (C) and needle pins are housed in elongated grooves
of the gear holder. The needle pin is pressed against the inner face of the second gear by spring (C) to allow
idle rotation of the second gear relative to the gear holder. When an excess torque is exerted on the bevel
pinion shaft, the needle pin is raised upon the projection of the second gear against the load of spring (C) to
allow idle rotation of the second gear. With this arrangement, the clutch slips when a violent torque is applied
to the tool as with the drill bit contacting steel wire within the concrete, protecting the operator from jerking or
being violently thrown around.
Fig. 7
Gear holder
Bevel pinion
Second gear
Cross section A - A

--- 16 ---
Tool holder
The tool holder is described below with reference to Fig. 8. As shown, three saddle keys are received in the
three respective elongated holes equidistantly located at the front cover. The cross sectional viewA-A
illustrates the mode in which an end attachment tool is held in position. With the grip turned in direction A, the
saddle keys are shifted out of the holes to unlock the attachment tool from the tool body.
When fitting the attachment tool, turn the grip fully in the A direction, insert the tool shank deeply until it hits
against the hole end. Then, turning the grip fully in B direction causes the attachment tool to be securely held
in position. In contrast to the previous knob-retaining structure, the DH 45SA uses three saddle keys locked by
turning the grip, which are able to securely hold the tool with a minimized deflection of the drill bit or other
attachment tool.
Tool
Section A - A
Grip
Front cover
Saddle key
Saddle key holder
A
B
Front cover
Tool
Saddle key Grip
Saddle key holder
Fig. 8

--- 17 ---
Wiring connections
The wiring connections are shown in Fig. 9. The Model DH 45SA adopts a plug-in module type wiring system
consisting of plug (A) ass'y and plug (B) ass'y. The plug (A) ass'y connected with the internal wires of the
stator is fitted into the housing. The plug (B) ass'y is fitted into the handle section through the plug holder and
is connected with the switch terminal and cord. Wiring connection is completed when the housing section, the
handle and handle cover section are all assembled and then fastened together with screws. With such a
wiring structure, assembling and disassembling procedures associated with wiring connection have been
largely simplified over previous models.
Housing
Cord clip
Vinyl tube
Plug (A)
ass'y
Cord
Side cover ass'y
Handle cover
Internal wire
of stator
Plug holder
Handle
Switch
Plug (B) ass'y
Plug (A)
ass'y
Plug (B)
ass'y
Plug
holder
Handle Handle
cover
Internal wire
of stator
Fig. 9

--- 18 ---
Handle and side handle
The double-layer handle structure consists of a plastic base reinforced with glass fiber and an outer layer of
soft resin molded together with the base.
The side handle consists of a steel nut in the base and a hard plastic and a soft resin outer cover molded
together to form the handle. The DH 45SA thus uses the newly designed soft-touch handle and side handle
for easier handling of the tool.
Fluid-tight, dust-proof structure
The crank case and cylinder case are tightly sealed with three O-rings, an oil seal and a rubber seal as
indicated in Fig. 10. This prevents grease from leaking from inside as well as dust particles from getting inside
the tool.
The tool holder is also protected from dust with a rubber front cap and a dust cover.
Fig. 10
Tool holder
Oil seal
Gear cover
O-ring
O-ring (C)
Dust cover
Front cap
Rubber seal
Crank case cover
Crank case
O-ring
Cylinder caseFront cover