IMPROVEMENTS IN POWER DRIVEN HAMMERS
Year: 1878

page_text: LETTERS PATENT to Alfred Davy, of Sheffield, in the County of York, Engineer,
for the Invention of "IMPROVEMENTS IN POWER DRIVEN HAMMERS."
PROVISIONAL SPECIFICATION left by the said Alfred Davy at the Office of
the Commissioners of Patents on the 17th October 1878.
ALFRED DAVY, of Sheffield, in the County of York, Engineer.
IN POWER DRIVEN HAMMERS."
"IMPROVEMENTS
This Invention relates to improvements in those hammers only which are usually
driven by bands or other gearing from shafting, and are technically known as
" power driven hammers," but is not intended to apply to any form of trip or helve
hammer. Such power driven lammers as ordinarily constructed have a revolving
shaft upon which there is an eccentric or cams, or a crank which gives motion to
the tup direct by means of a connecting rod. This shaft works in bearings which
are fixtures to the main frame (or otherwise) of the hammer, and so far as I am
aware this shaft has never been arranged to rise and fall, or to be raised and
lowered in order to regulate the blow of the hammer whilst at work. The force of
the blow has therefore been practically invariable.
Now the first part of my Invention consists in so mounting this shaft that it is
movable vertically (ie., towards and from the anvil), and in some cases in balancing
it also, so that it can be easily raised or lowered or will rise and fall of itself to
regulate the approach of the tup to the anvil, and the force of the stroke or blow at
the will of the operator. I effect this by any ordinary mechanical means, such as
by mounting the shaft in bearings in blocks sliding in the hammer standard or in a
cradle working on a centre pin or in a sliding frame, any of which can be made to
rise or fall automatically or be raised or lowered by means of levers or screws
worked by the hand or foot of the operator whilst the hammer is at work or at any
other time.

page_text: In all cases where levers are adopted for this purpose I propose to use a balance
weight sufficiently heavy to keep the tup from striking the face of the anvil when
the hammer is running but not in actual use.
When the hammer is in use the tup can be brought down to work as near the
anvil as may be required by means of the levers or screw above mentioned.
The second part of my Invention relates to the connection between the tup of
the hammer and the connecting rod, through which it is worked from the eccentric
or crank on the driving shaft, and consists in applying an elastic medium between
the two as follows:-For this purpose cushions of india-rubber are applied inside or
outside the tup or on the connecting rod, or in any convenient position between or
in connection with the connecting rod and the tup, but so that in all cases the
power from the connecting rod giving motion to the tup shall be transmitted by
the india-rubber. The connection between the tup and the connecting rod which
works it is so made that the two travel simultaneously, and make the same length
of stroke (except the difference due to the elasticity of the india-rubber), or the
connection may be so arranged that the connecting rod can be made to travel a
part of the stroke (which can be varied) without moving the tup, or in other words
a certain amount of play may be allowed if desired between the connection and the
tup, or between the india-rubber which gives motion to the tup from the connecting
rod.
The use of india-rubber between or in connection with the connecting rod and
the tup, or between the driver of the tup and the tup itself, prevents or minimises
the shock or concussion to the connecting rod, crank, or eccentric, or driving shaft
and working parts of the hammer.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Alfred Davy in the Great Seal Patent Office on the 17th April 1879.
ALFRED DAVY, of Sheffield, in the County of York, Engineer. IMPROVEMENTS
IN POWER DRIVEN HAMMERS."
"
This Invention relates to improvements in those hammers only which are usually
driven by bands or other gearing from shafting, and are technically known as
"power driven hammers," and is not intended to apply to any form of trip or helve
hammer. Such power driven hammers as ordinarily constructed have a revolving
shaft upon which there is an eccentric, or a crank which gives motion to the tup
direct by means of a connecting rod. This shaft works in bearings which are
fixtures to or in one with the main frame of the hammer, and so far as I am aware
this shaft has never been arranged to be raised and lowered in order to regulate the
force of the blow of the hammer, and the position of the stroke of the tup whilst at
work. The force of the blow and the position of its stroke have therefore been
practically invariable.
Now the first part of my Invention consists in so mounting this shaft that it is
movable towards and from the anvil, and in balancing it so that it can be easily
lowered to bring the stroke of the tup nearer to the anvil and regulate the force of
the blow at the will of the operator, and so that when no work is being done it
will rise of itself whilst the hammer is still running to prevent the hammer striking
the anvil. I effect this by any ordinary mechanical means, such as by mounting"
the shaft in bearings in blocks sliding in the hammer standards, or in a cradle
working on a centre pin, or in a sliding frame working up and down on
the standards, any of which movable supports for the shaft can be made to rise
automatically or can be lowered by means of a lever handle or treadle whilst the
hammer is running. For this purpose I propose to use a balance weight sufficiently
heavy to keep the tup from striking the face of the anvil when the hammer is
running but not in actual use. When the hammer is in use the tup can be brought
down to work as near the anvil as may be required by means of the handle or
treadle above mentioned which is connected to the movable support of the shaft.
The second part of my Invention applies more particularly to quick running ham-
mers, making say from five hundred to seven hundred and fifty blows per minute, in
which the shaft would not be generally made movable as above described, although the
india-rubber cushions may also be applied in connection with movable shafts. It relates
to the connection between the tup of the hammer and the connecting rod, through
which it is worked from the eccentric or crank on the driving shaft. Cushions of
india-rubber.are fixed on the tup spindle inside and outside the tup, so that the
power from the connecting rod giving motion to the tup shall be transmitted by the
india-rubber. Between the india-rubber cushions and the tup a certain amount of
play is allowed in order that the tup in falling shall be entirely independent of its
spindle and connections, so that the force of the blow shall be due solely to the
velocity and weight of the tup, and shall not be accelerated or retarded at the
instant the work is struck by the india-rubber cushions.
The india-rubber cushions prevent or minimise the shock or concussion to the
driving shaft and other working parts of the hammer, and the play between them
and the tup serves to accomodate the hammer to work, varying in size within
certain limits, so that the india-rubber cushions need only be about 11, or 2 inches
in thickness, the play being increased or diminished by adjusting the cushions for
work varying beyond those limits.
DESCRIPTION OF DRAWINGS.

page_text: A, A, are the standards of the hammer frame; B, the anvil, and C, the tup
working up and down guides between the standards as usual; D is the shaft from
which the tup C is actuated in the usual manner by means of an eccentric or crank
E. on said shaft. The shaft is mounted to rotate in bearings in blocks F fitted
to slide up and down in guides G in the upper part of standards A; H are levers
pivoted to the standards A at rear of the bearing blocks F through slots in which
the said levers pass as indicated by dotted lines in Figure 2. The said levers
are weighted at their rear ends to counterbalance the tup C and shaft D, and
raise or move them away from the anvil B. At their front ends they are con-
nected by rods I with a treadle K (or a hand lever), by which the workman can
lower the shaft D and tup C sufficiently to enable the "pellet " to strike the work
on the anvil. The part of the levers H which passes through the slots in the
bearing blocks F is slightly rounded on the upper and lower edges as shown.
Figure 3 shows on a larger scale details of the connection between the tup C
and the eccentric or crank connecting rod E'; L is the tup spindle jointed to the
lower end of the said connecting rod, and working through a guide M. bolted to
the standards A. The tup C is made of cast steel and is constructed with a
through aperture from front to back, in which is located the lower one N of two
india-rubber disc-shaped cushions N, N¹, fixed on the lower end of the tup
spindle L. The latter passes freely through a hole in the top of the tup and is
screw-threaded to receive nuts by which the india-rubber cushions are adjusted
and fixed at such distance apart as to leave an amount of play between the said
cushions and the part of the tup which they embrace, suited to the size of the
work to be forged. The india-rubber cushions are backed up by flanged or cup-
shaped metal discs between the india-rubber cushions and the nuts.
Having described the nature of my Invention, and the manner of performing the
same, I declare that what I claim as my Invention to be protected by the herein-
before in part recited Letters Patent is,
1st, Mounting the shaft of a power driven hammer in bearings in a support
or supports movable towards and from the anvil, substantially as and for the
purpose specified.
2nd Connecting the tup of a power driven hammer loosely to a single spindle
by means of a pair of india-rubber disc-shaped cushions, fixed adjustably on the
spindle with a certain amount of play between them and the top of the tup which
they embrace, substantially as and for the purpose specified.
In witness whereof, I, the said Alfred Davy, have hereunto set my hand and
seal, this Sixteenth day of April, in the year of our Lord One thousand
eight hundred and seventy-nine.
ALFRED DAVY. (L.S.)