Transposing Mechanism for Pianofortes and other Keyboard Instruments.
Year: 1897

page_text: · PROVISIONAL SPECIFICATION.
Transposing Mechanism for Pianofortes and other Keyboard
Instruments.
I, EDMUND HENRY GIGNEY, of 450, Holloway Road, London, Pianoforte
Manufacturer, do hereby declare the nature of this invention to be as follows:-
The object of my invention is to provide simple and effective mechanism for
transposing the notes of a pianoforte or other keyboard instrument according
to the key in which it is desired that the piece of music shall be performed.
I pivot the action frame or action standards in such manner that the lower part
can be swung or moved back so as to clear the keys while the upper part or
damper rail is swung or moved forward; the keyboard frame with keys can
then be slided to one side or the other as required. The action frame may
suitably be moved by means of a pull knob on a rod at the left of the keyboard;
this rod is jointed to the lower arm of a double armed lever, the upper arm or
arms of which by a rod or rods is connected to the lower end of the action frame.
Thus by pulling the knob forward against a stop, the lower end of the action frame
is pushed back from over the keyboard. The keyboard frame can then be moved
laterally as required for transposing. It is provided with a push in the lock
front for moving it said push working in a slot or it may have a knob under-
neath. The keyboard frame has to be bedded to the keybottom and is kept in
position by means of slotted brass plates with screws in the back rail and front
rail.
Transposing Mechanism for Pianofortes and other Keyboard
Instruments.
I, EDMUND HENRY GIGNEY, of 450, Holloway Road, London, Pianoforte
Manufacturer, do hereby declare the nature of this invention and in what
manner the same is to be performed, to be particularly described and ascertained
in and by the following statement: --
The object of my invention is to provide simple and effective mechanism for
transposing the notes of a pianoforte or other keyboard instrument according
to the key in which it is desired that the piece of music shall be performed.

page_text: I pivot the action frame or action standards on a horizontal pivot at each end
so that the lower part can be swung or moved back to clear the keys while the
upper part or damper rail is swung or moved forward, to clear the strings; the
key frame with keys can then be slid to one side or the other as required.
The action frame may suitably be moved by means of a pushing and pulling
rod. By moving this rod in one direction against a stop the lower part of the
action frame is pushed back from over the key frame which can then be moved
laterally as required for transposing, by preference by means of a knob in front
of the piano or underneath. The key frame has to be bedded to the key bottom
and is kept in position by means of slotted brass plates with screws in the back
rail and front rail.
Fig. 1 on the accompanying drawing is a front elevation, Fig. 2 a sectional
end view Fig. 3 a plan and Fig. 4 a detail view of a suitable construction of the
transposing mechanism and parts connected therewith as applied to a piano.
The action frame A is pivotted about centrally in vertical height on a hori-
zontal pivot A at each end to the sides B of the piano case, so that the lower
part by means of the push and pull rod D can be swung backwards into the
dotted position to clear the keys while the upper part or damper rail is swung
forwards to clear the strings. The key frame C with keys can then be slid to
one side or the other to the required extent. The spring M serves to bring
the action frame back into the normal vertical position. The action frame A
has a comb shaped plate A2 and in one of the tooth spaces of same the upstanding
finger C on the key frame will be held when the action frame A by means of the
push and pull rod D has been pulled back into its normal position shown in
full lines. Each tooth in the plate A² corresponds to a different key. The travel
of the rod D is limited by the knob coming against the name board F.
In order to allow the so called prolongues on the bottom of the action frame
to clear the keys, when the action frame is swung back, I chamfer the back or
inner ends of the keys N at N¹ to a suitable extent as shown in Fig. 4 and black
lead them.
The keyframe C is bedded on to the key bottom G and is kept in position by
means of pins in slots C in the back rail and front rail of same, the pins or
screws H being fixed in the keyboard bottom. I is a knob working in a slot
plate K in lock front for shifting the key frame C by. The name board F is
marked with index lines for the different keys and the keyboard has a pointer
to indicate the key to which the key frame is shifted.
Having now particularly described and ascertained the
vention and in what manner the same is to be performed
claim is:-
nature of my said in-
I declare that what I
1. In a transposing mechanism for pianofortes and other keyboard instruments
the action frame mounted on horizontal pivots in combination with means for
swinging it thereon so that its lower part can be swung back to clear the keys
and the upper part be swung forward to clear the strings whereupon the key frame
can be shifted laterally to the desired extent and the action frame then be
returned to its normal position substantially as set forth.
2. In a transposing mechanism the action frame mounted in horizontal pivots
in combination with means for swinging it thereon, keys with chamfered off
back ends to clear the prolongues on the action frame, a key frame capable of
limited lateral movement on the key bottom, and means for holding it in the
position according to the desired key substantially as set forth.
3. In a transposing mechanism the combination of the action frame mounted
in borizontal pivots, a rod attached to the lower end of the action frame for
swinging it back and forth, a comb shaped plate on the action frame, a key
frame capable of limited movement on the key bottom, and a finger on the key
frame engaging with said comb for holding the key frame in position according
to the desired key substantially as set forth.

page_text: 4. In a transposing mechanism the combination of the action frame mounted
on horizontal pivots, means for swinging it thereon, a frame provided with
slotted plates, pins on the key bottom working in the slots, a knob on the key
frame for moving it by, and a plate fixed at the front of the instrument with
slot for limiting the movement of the knob therein substantially as set forth.
Dated this 28th day of April 1898
JENSEN & SON,
77, Chancery Lane, London, W.C., Patent Agents.