US1496563A - Felt for piano hammers - Google Patents

Description

June 3 1924.

E. SYHRE FEL'T FOR PIANO HAMMERS Filed April 1, .1.920

Patented June 3, 1924.

` UNITED iSTATES EDMUND SYI-IRE, OF DRESDEN, GERMANY.

FELT FOR PIANO HAMMERS Application filed April 1,

To aZZ 'whom t may concert/t;

Be it known that I, EDMUND SYHRE, a citizen of Germany, residing at Dresden, in i the Republic of Saxony, Germany, have inventedcertain new and useful Improvements in Felt for Piano Hammers, of which the following` is a specification.

This invention relates to an improved method for felting piano hammers.

In the accompanying drawings:-

Figs. 1 to 4 illustrate the usual known method.

Fgs. 5 and 6 being illustrations of my improved method. With the known method for the felting of piano hammers approximately square felt plates of wedge-shaped longitudinal section (Fig. 1) are used, which through cuts which are not straight but run at a certain angle the one towards the other isdivided into strips a (Fig. 4). The cores c o-f the hammer heads which at least for the deeper notes are covered with the so-called under felt b, are pressed, according to most of the usual manufacturing methods, upon the back of such a felt strip after they have been previously fastened together by means of a ola-mping instrument.

The strip of felt is thus pressed into a channel which gets gradually narrower from the bass to the treble and the lateral flaps of the felt strip after they have been painted, with glue are pressed by lateral cheeks against the lateral surfaces of the cores c. In this manner rather strong` pressure of the strip of felt is efe-cted which gradually increases from the bass to the treble, the reduction in the size of the strip being shown in Figs. 2 and 3 and from the dotted lines in Fig. 1. This unequal compressing of the felt corresponds to the requirement that the hammers in the bass part may be comparatively soft but that those in the treble part must be Very hard for the reason that the short strings of the highest tones sound only with suflicient fullness and strongness under a very hard blow. This eXigence is taken into consideration already when the felt plates are being manufactured and in such 'a measure that for the unequal compressing of the felt when felting the hammers there remains very little to be done in this respect.

In Fig. 1 of the drawings there is indicated by the hatching which indicates the fiber, how with the gradual decrease of the height 1920. Serial No. 370,593.

of the felt plate its density and hardness gradually increase.

It has been proposed to obtain this gradual increase in the hardness of the felt by the distribution and treatment of the felt strip but there is not always obtained the desired result to get felt plates of the required dimensions and the desired graduation of density and hardness which demands, in every case well skilled factory hands and very expensive handwork.

There has further to be taken into consideration that, as far as the quality of the felt is concerned, that part of the felt plate destined for the treble must always determine the quality so that the very best and most expensive felt has to be used for instruments of medium quality '-"for which, without any inconvenience as regards the fullness and lasting of the tone, the felt could well be of somewhat lower quality at least for the lower tones. a

It is not possible with the well known manufacturing methods to make uniform felt plates from felt of assorted qualities. It must not be overlooked that it is not easy to cut the felt plate into strips a owing to the wedge shape of the plate and of the strips and that this cannot always be done without waste.

According to my invention a uniform felt. strip reaching over the entire length of the set of han'nner heads is no longer used. A strip of corresponding length is composed of several pieces, in this manner essential technical effects as well as economic a-dvantages are obtained. It is no longer necessary that the pieces which compose the felt plate be of wedge-shaped cross section but they may be flat with beveled edges as shown. Herefrom follows at first the advantage that it is easy to cut out the pieces from a felt sheet without any waste.

In this manncr I have solved the problem by making the felt for the coveriug of piano hammers either in sheets or in strip roll form, each piece of felt being throughout of uniform quality. The manufacturer can thusA produce perfect hammers foi` instruments of medium quality without considerable expense, as for the higher tones he can use felt of even better quality than it was possible hitherto, he being able to use for all the other hammers a felt of a much cheaper quality.

In F igs. 5 and 6 a felt strip made accord- ;grade for use with the short thin wires under highV tension and to use cheaper grades of felt where softer hammer heads are desirable and where there is less wear and disintegrating strains on the feet. Figs.

5 and6 showthese separate pieces or sect-ions of the strip arranged in proper order according to size.

The Steps which can be seen inFig. land 'which are caused by the difierence in thickness of the parts, will automatically disap- :pearwhen the cores of the hammer heads are pressed upon the felt strip. If the dotted line indicates as in Fig. 1, the final compression of the felt the graduation of the thickness and hardness which, according to the `known method of manufacture is obtained through the wedge Shape of the felt plate andthrough the diflerent distribution of the fibers along the entire length of the plate, nowjobtained quite automatically through thecompression of the pieces of Originally ,prismatic Shape. At the joints of the pieces always onehammer Will be wasted in the covering of which the edges of the two adj acent pieces of felt join .but this does not yinatter, there being generally added several from the base to the treble odd hammers to every set of hammer head cores. To avoid the waste of 'hammers at the joining lines there could be inserted between each group of hammers filling pieces c] which are' somewhat slightly larger than the cores (Fig. 5). Otherwise the felting method does not dift'er from the usual manufacturing method. I claim 1. A covering for hammer heads comprising a plurality of Sections of difierent dimenions and of different grades of material, the Sections being of lengths corresponding to the separate groups of hammer heads from the base to the treble and being arranged end to end and with the sectionsof the better grades of material cut in smaller sizes than the sections of poorei` grades of material for use in the treble end groups and the Sections graduated according to size and grade from the base end to the treble end of the covering.

2. A covering for felting piano hammers, composed of a row of group length sect-ions of coVering material arranged end to end, and the Sections being of different thicknesses and Widths and diminishing inthickness and increasing in the grade of the material of the sections throughout the groups of the hammer heads. i

In testimony whereof I afiix my signature in presence of two witnesses. f I

i EDMUND SYHRE.

VVitnesses:

C, HEINE MUHLHAUsnN. GUSTAV MLLER.

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