Dynamic Damper With Leaf Spring; Vibration-Proof Handle Thanks To The Transatory Unit And The Neidhardt Spring - Hitachi H 45MRY Technical Data And Service Manual

8-2. Dynamic Damper with Leaf Spring

The vibration caused by hammering operation of the
Model H 45MRY is transmitted to the cylinder crank
case, back cover, housing and finally to the weight
through the leaf spring supporting portion. Then the
weight moves in the reverse direction of the
transmitted vibration to negate the vibration of the
main body (Fig. 3).

8-3. Vibration-proof Handle thanks to the Transatory Unit and the Neidhardt Spring

The Model H 45MRY has the vibration-proof handle equipped with the transatory unit and the Neidhardt spring.
Structure of the transatory unit
The main body (cylinder crank case) is connected to
the upper handle through four cylindrical rubbers
(handle dampers). These rubbers are rolled and
compressed on the inclined surface to absorb the
vibration. Since the transatory unit has nonlinear
spring characteristics, the spring constant is lower
than the conventional shearing type vibration-
proofing structure. Thus the Model H 45MRY can
provide high vibration-proofing effect with good
cushioning properties. The joint of the slotted groove
and the cylindrical convex is provided at the center to
prevent the handle from being pulled out by twisting
or pulling in hammering operation (Fig. 4).
Vibration
Handle side
proof rubbers
Main body side
(a) At no-load
Fig. 4
Vibration of
the main body
Vibration of
the main body
Cylindrical rubbers
(handle damper: 4 pcs.)
Slotted groove
Handle damper retaining material
(Cylinder crank case)
Rolled and compressed
Reaction
(b) At full-load
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Vibration of
the weight
Vibration of
the weight
Fig. 3
Handle damper
retaining material
(handle side)
Cylindrical
convex
Pressing force
of the main
body