Plucking mechanism for a stringed instrument

A plucking mechanism for a string instrument, for instance a harpsichord consists of a mandrel directly coupled to the key, the mandrel being provided with a protruding edge which plucks the string.

The present invention refers to a plucking mechanism for a stringed 
instrument at which the pressing down of a key causes a sound from a 
string by means of plucking the string with a pointed means. 
During several centuries the plucking mechanics in the above described type 
of string instrument which for instance could be a harpsichord has in 
principle not been subject to any essential changes in design. The 
plucking of the string is thus achieved by coupling the key to the pointed 
means which plucks the string via a considerable number of links and arms 
with appertaining frictional points which require continuous service and 
where the harpsichord players often have to carry out adjustments 
themselves in order to make the plucking mechanisms work satisfactory. In 
these mechanisms changes continuously appear, which changes increase or 
decrease the distance between the pointed means and the string which 
causes variation in intensity and timbre. 
It is an object of the present invention to achieve a plucking mechanism 
which uses modern construction material and modern production technique 
and which thus makes the mechanism substantially cheaper and more reliable 
as compared to the previously used design. The characteristics of the 
invention will appear from the claims attached to the specification. 
In the plucking mechanism according to the invention the moveable parts are 
replaced by one single part which almost completely eliminates position 
changes and causes a constant intensity and timbre, an almost soundless 
playing function, a decreased wearing and an improved plucking of spun 
strings by replacing the traditional pin by a broader and more elastic 
tone generating means.

In FIGS. 1 and 2, reference 3 denotes the plucking means, the so called 
mandrel, which is attached to a key denoted 1 in FIG. 3, said key being 
journalled on an axis 2. When the key is forced downwards the lower 
protruding edge 5 of the mandrel plucks string 4 and initiates a vibrating 
of the string. The mandrel should be made of a relatively soft material 
for instance rubber with a degree of hardness of about 70 Shore. The 
string will thereafter vibrate as long as the key is in its lower 
position. When the key returns to its rest position the pointed part of 
the mandrel will again touch the string but since the mandrel is provided 
with a slot 6 the string will only be touched smoothly and will not be 
brought into a vibrating state. In order not to risk an extension of the 
slot 6 the mandrel should be provided with a bore 7 at the inner end of 
the slot. 
In order to make an adjustment of the distance between the mandrel and the 
string the socket 8 is provided with a screw 9 by means of which the 
mandrel is vertically displaceable. The mandrel could also be provided 
with a bore 10 in which a conical screw is inserted so that when the screw 
is introduced into the mandrel the soft parts around the screw are 
expanded whereby the pointed end 5 of the mandrel is brought closer to the 
string so as to achieve an increased intensity. 
As the mandrels are mounted on top of the strings dampers 11 can be located 
below the strings whereby the same effects can be achieved as in a grand 
piano, i.e. firstly an individual damping of each string and secondly a 
simultaneous release of all strings. As appears from FIG. 3 the mandrel 3 
will release the string 4 from the damper 11 when the string is brought 
downwards, said damper being attached to a plate spring 12. Simultaneously 
all strings can be released from their dampers by mounting all the dampers 
on a common rod 13 journalled at 14 whereby by means of a pedal rod 15 all 
damper can be controlled simultaneously in a traditional way. This system 
will make new timbres possible in the harpsichord by means of coupled 
vibrations from other strings which is especially important in figurations 
within the same chords. 
A further advantage of the invention is that the improved functional 
precision implies a possibility of designing the complete keyboard with 
the plucking means in such a way that it is sidewise displaceable which 
permits changes in the distance between the string and the plucking 
mechanism. 
It should also be noted that the plucking mechanism can be located under 
the strings and thus on top of the keys.