Hitachi DH 40MRY Technical Data And Service Manual page 6

4-2-2. Vibration reduction mechanism (Dynamic damper with leaf spring)
The Model DH 40MRY is equipped with Hitachi's own dynamic damper that absorbs vibration from the main body
by means of resonance of the leaf spring and the spindle. As a result, the vibration level of the Model
DH 40MRY is remarkably lower than the current Model DH 40MR.
4-2-3. Newly designed vibration-absorbing handle
The Model DH 40MRY is equipped with the new vibration-absorbing mechanism based on the same Hitachi's own
vibration-absorbing mechanism as the current Model DH 40MR that absorbs vibration by rolling and compressing
the four cylindrical rubber cushions on the inclined surface. In the new vibration-absorbing mechanism, the shaft
fixed to the handle is turned in conjunction with the handle movement and the four cylindrical rubber cushions are
rolled and compressed to absorb vibration more efficiently. The cushion effect not only greatly reduces vibration
but also maintains good operability.
4-2-4. Self-drilling (Good feeling)
Thanks to the computer-simulated optimum striking characteristics, the quantity of body jumping is less than that
of the current Model DH 40MR and the working tool smoothly penetrates into the workpiece with a light pressing
force. The Model DH 40MRY realizes quicker self-drilling with better impact feeling.
Impact energy
Maximum compressed air force (piston force)
Quantity of body jumping
4-2-5. Dial type, constant speed with variable speed control
The Model DH 40MRY is equipped with a built-in electronic control circuit that
can adjust the number of hammering steplessly between 1320 and 2650 min
with the dial. Even though the load varies, the Model DH 40MRY provides better
operability and stable and efficient drilling performance because the constant
speed control minimizes changes in number of rotation and hammering.
4-2-6. Soft-touch grip for easier handling
The double-layer molded handle consists of a nylon resin base covered with a soft plastic layer to ensure a soft
touch and firm, non-slip grip of the handles.
4-2-7. Change lever for switching between "Rotation and hammering," "Neutral" and "Hammering only"
The Model DH 40MRY provides three functions, "Rotation and
hammering" function (for drilling), "Neutral" function (for positioning the
tool tip) and "Hammering only" function (for chiseling and chipping.)
These function modes can be easily switched by using the change lever.
The tool angle can be easily changed in 12 steps by turning the grip with
the change lever positioned at "Neutral."
4-2-8. Needle-pin type slip clutch
The Model DH 40MRY is equipped with a needle-pin type slip clutch for higher slip torque accuracy and
enhanced safety (same as the Model DH 40MR.)
About 5% up
About 33% down
About 36% down
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Speed-adjust dial