GB286976A - Improvements in and relating to the action or hammer-operating mechanism of stringed percussion musical instruments - Google Patents

Abstract

286,976. Armstrong. W. S. Aug. 16, 1927. Pianoforte actions; keys and keyboards; silencing.-In a stringed percussion musical instrument, a rocking seat-block provides a rest for the hammer in both the rest and check positions, and is operated to give a further thrust to the hammer after he hammer has been moved initially by direct action of the key. In a horizontal instrument, the key 1, Fig. 1, pivoted at 3, carries the hammer 9 in alignment, by means) of a hinge 5, the hammer being directly raised on depression of the key. Simultaneously, the seat-block 15 is turned about its pivot 16 by means of a rocking- beam 12 and links 14, and, by the part 24 engaging a notch 11, accelerates the motion of the hammer. After striking the string, the key remaining depressed (Fig. 2), the hammer passes a latch 20, which is moved by the seat block and checks rebound of the hammer, and comes to rest on the part 24 of the seat-block. The damper is lifted by a forked piece 6 carried by the key, and passing on either side of the string 8 as shown. A spring 17 returns the parts on release of the key. In a modification, the checking-latch 20 is carried by the hammer and engages a part of the seat block. In an upright instrument, the hammer hangs more or less vertically from the end of the key. The parts are pivoted on continuous axles, and. with the board of the case which lies in front of the keys, may form a single withdrawable unit. When withdrawn, a check bar provided over the hammers will convert the unit into a. silent practising-apparatus. The keys are guided by lugs 4 attached to their front ends, and working on vertical pins between stop rails attached to the front board of the case. Dampers 35, Fig. 4, may be mounted by flat springs 34 on a bar 33 which may be rotated when it is desired to raise them all simultaneously. When the strings of the instrument lie close together, the black and the white may each be provided with raised finger-plates staggered in two rows and of a width nearly twice the string spacing.