An Improved Piano-forte Action.
Year: 1893

page_text: Date of Application, 16th May, 1893-Accepted, 22nd July, 1893
COMPLETE SPECIFICATION.
An Improved Piano-forte Action.
We, JOHN HOPKINSON and JAMES HOPKINSON, of 34, 35 and 36, Margaret
Street, Cavendish Square, and 44, Fitzroy Road, Regent's Park, in the County of
Middlesex, Piano-forte Manufacturers, and BENJAMIN JOSIAH WESTON, of 97,
Walford Road, South Hornsey, in the County of Middlesex, Foreman to the
aforesaid John Hopkinson and James Hopkinson, 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 :-
This invention relates to what is known as the "Hopkinson" grand piano-forte
action, and consists of an improvement whereby the working of the mechanism is
rendered more efficient and the "touch more delicate, greater durability being at
the same time secured.
In the accompanying drawings,
""
Fig. 1 is a side elevation of the "Hopkinson" action constructed in the improved
manner the subject of the present invention; the hammer-rest, hammer-rail, button-
rail and key-frame being shown in section. In this figure, the mechanism is
represented in its normal position.
Fig. 2 is a corresponding view, illustrating the mechanism in the position it
assumes after the hammer has struck the string and fallen back against the
check.
Fig. 3 is a front elevation of part of the sticker.
A is the hammer-head, A' the hammer-tail, B the hammer-shank and C the
hammer-butt. The hammer is pivoted to a block D adjustably attached by a screw
to the hammer-rail E. E' is the hammer-rest, and E2 the hammer-rest-rail. The
key F works on a pin 9 projecting from the key-frame G, and is guided by a front-
pin g¹ extending from the said frame and engaging in a slot in the front end of the
key. is a washer made of soft material and acting as a pad. 93 is the key-rest..
HH' is the jointed sticker, and h the sticker-pin. c is a bearing on the hammer-
butt C. This bearing, which is for the upper part of the sticker, is preferably
made of textile material. The part H of the sticker is jointed at ; to the other
part H. K is the regulating lever or bar, to which the part H' is jointed at j'.
k and are screws for securing the regulating lever or har to the key F.
k² is a
set-screw for raising or lowering the end of the lever K after the screw k¹ has
been slackened. L is the relieving hopper. L' is the stop-wire, L³ are the stop-
washers and L is the regulating button for the stop. M M¹ is the relieving spring,
and m the block by which it is connected to the key F. N is the relieving button,
O the button-rail, and P a spacing block interposed between the rails O and E.
Q is the check-wire, and the check. R represents the string above the
hammer A.
When the key F is depressed, the hammer strikes the string R; the two
parts H and H₁ of the sticker being brought into line, and the hopper L into
contact with the button N. The continued depression of the key brings the end
of the same against the washer g³, and causes the part H¹ to turn
on the
centre (owing to the contact of the hopper L with the button N). The
turning of the part H' takes it out of line with the part H, and thus reduces
the distance between the centre j¹ and the bearing c. This relieves the hammer,
and permits it to drop until its tail A' comes into contact with the check Q',
as shown in Fig. 2. When the key is released, it falls back into the position
represented in Fig. 1; the hopper L being raised, the part H¹ turned on the
centre j¹, and the part H brought against the stop-washers L by the spring MM*.
The stop-wire L' works in a slot h³ in the part H, and serves to prevent lateral

page_text: movement of the hopper L; thus keeping the hopper in its proper relative
position with regard to the other parts of the action and to the adjoining
hoppers, and lessening the wear on the centres j, j and j. The stop L³, being
mounted on the pivoted spring-actuated hopper L, gives a certain elasticity to
the touch which is of great advantage. Moreover, with a view to affording ready
access to the adjusting screws k' and k², the stop L2 is more advantageously
mounted upon the relieving hopper L than upon the lever or bar K.
The action is regulated by advancing or retiring the screw-button L³ or the
button N to the desired extent, or by raising or lowering the lever or bar K,
or by altering the tension of the spring M M' by bending the free arm M¹ to
the required degree.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, we claim :-
1. The improved piano-forte action constructed and operating substantially as
described with reference to the accompanying drawings.
2. The improved piano-forte relieving action constructed substantially as herein
described, and having a sticker-stop mounted on the relieving hopper and working
through a slot in the jointed sticker, accuracy in the movement of the relieving
hopper being thereby ensured.
Dated the 10th day of May 1893.
G. G. M. HARDINGHAM,
191, Fleet Street, London, E.C., Chartered Patent Agent.
G. G. M. HARDINGHAM,
191, Fleet Street, London, E.C., Chartered Patent Agent.