Stroke adjustment device for keyboard instrument

A stroke adjustment device for a keyboard instrument including a keyboard having a plurality of keys arranged side by side in a left-right direction thereof, each extending in a front-rear direction thereof and configured to be swingable about a pivot provided in the vicinity of a center of the key in a longitudinal direction thereof, a plurality of actions each placed on an upper surface of an associated one of the keys at a location rearward of the pivot and configured to move in accordance with key depression of the associated key, and a plurality of hammers provided in association with the respective actions and each configured to pivotally move in accordance with motion of an associated one of the actions to thereby strike a stretched string, the stroke adjustment device being configured to adjust a keyboard pillow which extends along the left-right direction of the keyboard and on which rear ends of the keys in a key-released state are placed, to a predetermined level to thereby adjust a key depression stroke of the keys and a hammer stroke of the hammers,

• the stroke adjustment device comprising:
• a keyboard pillow-lifting mechanism configured to lift up and down the keyboard pillow between a predetermined reference level and a pushed-up level higher than the predetermined reference level by a predetermined height;
• an operation mechanism configured to be manually operated so as to drive the keyboard pillow-lifting mechanism;
• and
• a driving force transmission mechanism configured to transmit a driving force generated by operation of the operation mechanism to the keyboard pillow-lifting mechanism,
• wherein the keyboard pillow-lifting mechanism comprises:
• a rotatable shaft extending below the keyboard pillow along the entire length of the keyboard pillow, the rotable shaft being connected to the driving force transmission mechanism;
• a plurality of gear portions provided on the rotatable shaft at respective predetermined locations in a longitudinal direction of the rotable shaft and configured to rotate in unison with the rotable shaft;
• a plurality of rack parts that are in mesh with the respective gear portions and are vertically movable;
• and
• a lifting part extending over the rack parts, and in contact with a lower surface of the keyboard pillow, the lifting part being configured to vertically move in unison with the rack parts in accordance with rotation of the rotatable shaft through a predetermined angle to lift up and down the keyboard pillow.