ATMOSPHERIC TRIP HAMMERS
Year: 1862

page_text: LETTERS PATENT to Bennet Hotchkiss, of New Haven, in the County of
New Haven and State of Connecticut, of the United States of America,
for the Invention of "ATMOSPHERIC TRIP HAMMERS."
Sealed the 18th March 1868, and dated the 20th September 1862.
PROVISIONAL SPECIFICATION left by the said Bennet Hotchkiss at the
Office of the Commissioners of Patents, with his Petition, on the 20th
September 1862.
I, BENNET HOTCHKISS, of New Haven, in the County of New Haven and
State of Connecticut, of the United States of America, do hereby declare the
nature of the said Invention for "ATMOSPHERIC TRIP HAMMERS," to be as
follows:-
The frame consists of two parts, whereof the lower forms a bed to which
the upper is bolted, an elastic substance being inserted under the washers of
the nuts in order to lessen the effect produced by the blow of the hammer.
The hammer is worked by means of an air cylinder, to which is imparted a
vertical reciprocating motion. Within this cylinder is fitted a piston, to the
rod of which the hammer is connected, the rod being enlarged at the part
where the connection is formed in order to prevent the liability of its being
broken. The atmospheric air is admitted into the cylinder through apertures
so placed as to allow the air to pass thereinto at such periods as to cause it,
by its compression, to act as a spring between the piston and the lower end
of the cylinder on the upward motion of the latter, and to impart an impelling

page_text: force to the piston in a downward direction on the downward motion of the
cylinder; or, instead of such apertures, two valves are fitted, one at the upper
part of the cylinder and the other at the lower part, with an air passage com-
municating between them, the rods of such valves being acted upon by coming
in contact with adjustable inclined planes fixed on the side frame of the
apparatus. The object of both these arrangements for admitting the atmo-
spheric air to the cylinder is to regulate the force of the striking power
imparted to the hammer without altering the speed of the driving shaft.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Bennet Hotchkiss in the Great Seal Patent Office on the
19th March 1863.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, BENNET
HOTCHKISS, of New Haven, in the County of New Haven and State of
Connecticut, of the United States of America, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twentieth day of September, in the year of our Lord
One thousand eight hundred and sixty-two, in the twenty-sixth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, the
said Bennet Hotchkiss, Her special licence, that I, the said Bennet Hotchkiss,
my executors, administrators, and assigns, or such others as I, the said a
Bennet-Hotchkiss, my executors, administrators, and assigns, should at any
time agree with, and no others, from time to time and at all times thereafter
during the term therein expressed, should and lawfully might make, use,
exercise, and vend, within the United Kingdom of Great Britain and Ireland,
the Channel Islands, and Isle of Man, an Invention for "ATMOSPHERIC
TRIP HAMMERS," upon the condition (amongst others) that I, the said
Bennet Hotchkiss, my executors or administrators, by an instrument in
writing under my, or their, or one of their hands and seals, should par-
ticularly describe and ascertain the nature of the said Invention, and in
what manner the same was to be performed, and cause the same to be $
filed in the Great Seal Patent Office within six calendar months next and
immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Bennet Hotchkiss, do hereby declare
the nature of my said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following 3
statement, that is to say:-

page_text: The object of this Invention is chiefly to regulate the blow of the hammer,
and give elasticity to the parts so as to give an elastic blow with the hammer,
and at the same time prevent the breakage of the parts, which is one of the
chief difficulties in the operation of trip and steam hammers. This hammer
is provided with an air cylinder, in which a piston is permitted to move and
act upon air contained in the piston in such a manner as to cushion the effect
of the blow, and give it a portion of elasticity. The piston rod in this machine
extends down from the piston in the air cylinder, and is connected below to the
hammer.
The first part of my Invention consists in the manner of connecting the
upper framework with the anvil block by means of the superposition of elastic
washers between the heads of the bolts which secure the said parts together
and the flanges through which the said bolts pass, and also by the super-
position of like washers between the nuts and washers at the ends of the
said bolts and the said flanges through which the bolts pass, as herein-after
more fully set forth.
The second part of my Invention relates to the combination with the air.
cylinder and hammer of certain air passages through which external air may
be received to modify the effect of the blow, and discharged to. allow the:
piston inside of the cylinder to slide freely in certain parts of its stroke, the
said passages being operative without being opened or closed by any automatic.
mechanism except the piston.
The third part of my Invention relates to supplying the cylinder with
air, and discharging air therefrom by means of certain valves, which, are
operated by mechanism for the purpose to vary and modify the stroke so as to
cushion the blow in the proper manner for the work to be performed. These
valves are placed near the ends of the cylinder, though not entirely at the
ends, and I prefer to operate them by means of mechanism which is automatic
in its operation, and which may be adjusted to suit the exigencies of
the case.
In general practice, perhaps, two adjustable inclined planes may
be the better means of operating these valves, though other devices may
be used.
The fourth part of my Invention relates to the combination with the valves
above-mentiened of the air passage connecting from one valve to the other,
so that the effect of the discharge of air through one valve shall be to force
the same air into the other end of the said cylinder. In the use of this
device the same atmospheric air is made available for working, the cylinder
without the necessity of any additional supply from the outside.
The fifth part of my said Invention relates to the construction of the piston

page_text: rod to obviate the well known difficulty of breakage thereof near the hammer,
and in connection therewith of the device, herein-after described, by which I
am enabled to pass the enlarged portion of said piston rod through the stuffing
box which leads' to the air cylinder above mentioned.
In the Drawings, Figure 1 is a front elevation of my improved atmospheric
hammer; Figure 2 is a side view thereof; Figure 3 is a vertical central
section showing the parts beyond the driving shaft, the driving shaft and
piston rod being shown entire instead of in section; Figure 4 is. a horizontal
section of the cylinder, and a portion of the ways or guides between which it
slides, showing the construction of the valves for admitting air to and from the
cylinder, and a device for operating the same; Figure 5 is a detail sectional
view, in elevation, showing the same feature of the Invention, and also the
independent air passages which may be used without valves, as will be more
fully described below; Figure 6 is a detail view, in vertical section, showing
the mode of connecting the upper framework to the anvil block so as to
secure the parts firmly in position, and yet prevent the breaking of the parts
by the concussion of the hammer; Figure 7 is a detailed view illustrating
the construction of the stuffing box in a manner to allow the enlarged portion
of the piston rod to be readily passed through from above, and the stuffing box
afterwards made available to make a close fitting joint around said piston rod,
as herein-after more fully described.
A is the anvil block or frame upon which the parts are supported. The
upper framework B is bolted to the lower or supporting frame A by means of
bolts N, N, as shown in Figure 6. These bolts are constructed in the ordinary
manner with heads f, nuts g, and washers h, as usual. To give some little
elasticity to this connection of 'the parts, I place elastic washers or rings i
between the heads of the bolts and the flanges, through which they pass to
unite the parts, and I also place elastic washers i between the washers h and
the flange above, through which the bolt passes for the purpose above stated,
and I screw up the nuts upon the bolts till the washers i are sufficiently
compressed to hold the upper end and lower parts firmly together, but not so
much but that they will yet yield slightly to the concussion produced by the
fall of the hammer. I prefer to make these elastic washers of india-rubber;
I do this to lessen the liability of breaking the frame or other parts of the
machine by the jar from the blow of the hammer. The upper part or upper
frame B is so constructed as to form guides C, C, to receive and guide the
air spring cylinder D, which is constructed in some respects similar to a
steam cylinder, with appropriate heads, and which receives motion from the
main shaft by means of the connecting rod T. This cylinder D has two or

page_text: more air passages a, b, in the side of the said cylinder which passages open from
the cylinder to the external air. Instead however of these open passages two
valves G, g, may be inserted in the side of the cylinder or valve chest attached
thereto, operated by adjustable mechanism, and this mode of construction I
prefer when the hammer is to be used for variable work. These valves
should be placed near the ends of the cylinder. to allow the stroke to be varied
to a considerable extent, though not so far as in any case to prevent the blow
from being cushioned so as to prevent damage to the parts. H is an air
passage which connects the openings which contain the valves G, g, and is
intended to allow the air which may be forced out of the cylinder at one end
to pass into the other end of the cylinder, so that no loss may be occasioned,
and no outside communication is in this case necessary. I is a piston arranged
within the cylinder D, and has its rod K extending through the lower head E
of the cylinder, and attached to the hammer L. As in all hammers con-
structed and operated by a piston rod there is some liability to break the rod
at its connection d with the hammer. I have endeavored to overcome this
objection and difficulty by making a rod larger at the connection d, and
reducing from that point to the proper size of the piston rod. To enable me
to do this I make a hole for the rod through the stuffing box gland W. and
also through the cylinder head E, of sufficient size to allow the enlarged
portion d of piston rod to pass freely, and to pack the stuffing box I place
within it plates e, e, each divided as represented in Fig. 7, and the hole through
these plates fitting the smaller part of the piston rod.
The said plates
being in parts can be placed in the box after the enlarged part of the rod
bas passed through, and the packing may be placed between the upper
and lower plates, and compressed in the ordinary manner.
O is the driving
shaft, which has its journals supported in boxes P, P. A pulley R is attached
to this driving shaft, and at the opposite end of the shaft a crank wheel is
fixed, in which a crank pin m is inserted, which crank pin extends through
the connecting rod T, the upper end of which is by a similar pin n connected
to the cylinder D. By applying power to the pulley R, motion will be
imparted to the shaft O, and thence through the connecting rod T reciprocating
vertical motion will be given to the pneumatic or air spring cylinder D, and in
consequence thereof the hammer will be lifted and forced.downwards towards
the anvil U, or any article placed thereon. During each elevation or
depression of the cylinder the piston will pass by the air passages a and b, and
compress all the air that may be in the cylinder between the air passage next
the cylinder head which is approaching the piston and the said cylinder head.
This compression of the air while the cylinder is descending will act as a

page_text: b
spring to overcome gradually the inertia of the hammer, and prevent the piston
from coming in contact with the lower head of the cylinder; so during the
descent of the cylinder the air will be similarly compressed in its upper part,
and will in like manner relieve the cylinder head above from the shock of the
blow. The quantity of air compressed in the cylinder materially affects and
controls the stroke of the hammer, and it will be obvious that by closing the
lower hole or passage b, and opening the upper, have a quantity of air to
compress below the piston equal to the contents of the cylinder below the
upper opening a; but by leaving the opening 6 open, the stroke is thereby
reduced, as a less compression of air takes place, as it is obvious that the
hammer will not be raised until the piston is met by the air below it in the
cylinder, and that the cylinder produces no material effect upon the hammer
between the points at which the air is left free to escape... This change, by
means of a series of openings in any ordinary work not largely variable, may
be sufficient for the purpose desired, but where a still greater range of
variation in the stroke of the hammer is necessary, I fix in the side of the
cylinder puppet valves F, G, as represented in Figs. 4 and 5. These valves
open inward, and the operation of opening them is performed the stems 7, 5,
of said valves, which extend out through the cylinder striking against the
adjustable inclined planes W, X, which are fixed upon the guide C for that
purpose. These valves may be usually kept closed by spiral springs or other-
wise, as may be desirable. It will be obvious by an inspection of the parts
that the inclined planes W, X, may be so adjusted as to open either valve at
any portion of the stroke which is likely to be desired. By this the effect of
the air cushion may be varied to any extent according to the work upon which
the hammer is to be used. By opening the lower valve before the cylinder
has reached its extreme height, the air compressed below the piston will pass
through the passage H and upper valve into the space above the piston. The
result is that the hammer begins its descent before the cylinder does, and
while the crank is passing its upper dead centre, and the hammer will reach
the anvil before the cylinder will have attained its lower extreme. But before
that point is reached by the cylinder the air from the upper part of the cylinder,
accumulated by the accelerated descent of the hammer, will be released by
opening the upper, valve, and the air thus contained in the space above the
piston will thus be permitted to pass down through the lower valve into the
cylinder below the piston, and the cylinder will ascend some little distance
before it will begin to raise the hammer. By this device the effect of the
"blow may be varied to any extent which is likely to be desired in ordinary
work. I am aware that a single puppet valve has been used in atmospheric

page_text: hammers to allow the air to escape from above the piston in the ascent of the
hammer, as described in the Patent granted by the Government of the United
States, April 17th, 1860, to Milo Peck; I do not claim a single valve used
in such manner uncombined with another valve or opening, by which the
action of the hammer may be modified.
But having 'fully described and ascertained the nature of my said Invention,
and in what manner the same is to be performed, I claim as new and useful
therein,―
First, the elastic washers i and bolts n, in combination with the supporting
frame A and upper frame B, in the manner and for the purpose herein set
forth.
Second, the two air passages a and b, in combination with a pneumatic or.
air spring cylinder, when the said air passages are arranged substantially in
the manner and for the purpose described.
Third, the valves F, G, arranged as described, in combination with the
pneumatic or air spring cylinder, operating in the manner and for the purpose
herein specified.
Fourth, the combination described of the valves F and G with the air
passage H for the purpose of changing the air from the upper to the lower
air spring, or vice versa, to lessen or increase the blow of the hammer without
changing the velocity of the cylinder, substantially as set forth.
Fifth, the enlargement of the piston rod in the manner described in com-
bination with the divided stuffing box plates or their equivalents, substantially
as and for the purpose specified.
In witness whereof, I, the said Bennet Hotchkiss, have hereunto set my
hand and seal, this Seventh day of February, One thousand eight
hundred and sixty-three.
BENNET HOTCHKISS. (L.S.)