US 4,580,456 AGranted

Balance weight transfer device for a vibrator

OwnerKikumithus Takanoinventor

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Abstract

On the rotary output shaft of a variable-speed electric motor, there is fixed a sector-shaped weight. On the weight body, diametrically opposite its principal mass there is provided a radial projection provided with a radially extending cavity in which there is slidingly received at the radially inner end a weight. A plunger is pressed by a spring against the slidable weight and projects radially outwardly of the cavity. As the motor output shaft rotates more quickly, the slidable weight slides radially outwards, resiliently compressing the spring and extending the plunger. As the motor output shaft is slowed in rotation speed, the spring recovers, withdrawing the plunger and pushing the sliding weight back towards the shaft. In an elaboration, the plunger is provided outside the cavity with a device for adjustably pre-compressing the spring by pulling out the plunger by a variable amount.

Claims7

Dependent claims

A variable-frequency balance weight for securement on the rotary output shaft of a variable-speed motor, said balance weight comprising:

a weight body including a hub portion constructed and arranged to be fixed on the rotary output shaft of the motor and a weight portion projecting generally radially outwards from said hub;
said weight body further including:
means providing an at least generally radially extending chamber;
a further weight means slidingly received in said chamber adjacent a radially outer end of said chamber;
and
spring means acting in compression between said further weight means and a radially outer end of said chamber for tending to urge said further weight means radially inwardly in opposition to centrifugal force, said spring means having such a magnitude of spring constant that in normal operation said spring may become at least partially compressed and said further weight means may travel radially outwards to a respective extent, thus modifying the moment of inertia of the balance weight;
adjustable means acting between said weight body and said further weight means for selectively pre-compressing said spring means to a desired extent;
said adjustable means being constructed and arranged to correspondingly shift at least part of said further weight means radially outwardly as said spring means is selectively precompressed to a desired extent.

5 more elements

Dependencies are inferred from the claim text.