Title:
PIANO ACTION MECHANISM IN WHICH SLOPED JACK IS USED
Document Type and Number:
WIPO Patent Application WO/2020/136932
Kind Code:
A1
Abstract:
The present invention resolves the structural defect in existing grand pianos of keys catching during pianissimo playing, the catching being caused by sliding friction between a jack and a roller. In addition, the present invention provides a piano having variable timbre due to movement of the string contact point. An action mechanism for a piano, the action mechanism being characterized by comprising a shank wheel Z in lieu of the existing hammer shank roller, and comprising a sloped surface A1b on the jack-body A1-side surface in lieu of the existing repetition lever. Due to this configuration, the shank wheel Z rolls over the jack projecting surface A1a during the escapement of the jack A at the last stage of depression of a key, and sliding friction during escapement is eliminated. Also, during the key return stage, the shank wheel Z rolls over the sloped surface A1b and smoothly rides over the jack projecting surface A1a. In addition, the present invention is characterized by having a knocker shank 21a and a catcher shank 21b in lieu of each existing hammer, the center of both the knocker shank 21a and the catcher shank 21b being pinned with a conrod X, and a shank flange c2 being moved by a camshaft W. Due to this configuration, the string contact point of a hammer head 22 can be moved in the string tension direction.
Inventors:
HIROKAWA HIDEKAZU (JP)
Application Number:
PCT/JP2019/017301
Publication Date:
July 02, 2020
Filing Date:
April 23, 2019
Export Citation:
Assignee:
HIROKAWA HIDEKAZU (JP)
International Classes:
G10C1/02; G10C3/18; G10C1/04; G10C3/16
Foreign References:
| JPS515007A | 1976-01-16 | |||
| JPS59151295U | 1984-10-09 | |||
| JPS515426U | 1976-01-16 |
Attorney, Agent or Firm:
TSUJITA, Tomoko (JP)
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