Improvements in Power Hammers.
Year: 1893

page_text: COMPLETE SPECIFICATION.
Improvements in Power Hammers.
I, JOSEPH O'BRIEN of 44 Cliff Street Boston, Suffolk County, State of
Massachusetts, United States of America, Mechanic, 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 pertains to power-hammers, so-called and relates to improvements
in the peculiar manner of mounting the hammer, as likewise to the mechanism by
which the action of the machine is controlled, so that it may be stopped, started, or
when in action enables a heavy or light blow to be delivered.
My invention consists primarily in providing a self-balanced spring-actuated
hammer which is mounted in standards or uprights, and loosely attached to the
free end of an oscillating helve or bar, the spring being positioned above and
below said helve in order to allow the amplitude of the oscillations of the helve
to exceed the travel of the hammer, and thus allows for varying thickness of metal
in process.
The drawings accompanying this Specification represent in Fig. 1 a side
elevation; Fig. 2 is a plan; Fig. 3 an end elevation of a power hammer
embodying my invention.
Fig. 4 is a modified form of helve.
Fig. 5 is a horizontal cross-section through the hammer and the guides.
Fig. 6 is a detail side sectional view of the rod and spring with the hammer and
helve in the vertical section.
In the operation of power-hammers it has been found that a blow, imparted by
some elastic medium, which thereby causes the hammer to strike the object
quickly and then leave it, possesses peculiar properties, chief among them which
is that the metal treated retains its heat for a longer time than when subjected
to a dead blow. The object of my present improvements is to obtain an
elastic blow.
In the drawings I have shown a bed-plate 2 provided with twin uprights 3' 3'
upon which are mounted the several elements comprising the power-hammer as an
entirety. At the front end of the bed-plate is situated the anvil 4, while removably
secured upon this end of the housings 3' 3' are similar guide posts 5 united at the
top by a tie-rod 6: within these guide-posts is fitted the hammer 7, which is
adapted to reciprocate in vertical paths. Upon and near the rear end of the
housings rise abutments, which are capped with a plate 8 to which is bolted the
fixed end of a spring helve 9. This latter is adapted to operate the hammer and is
oscillated by means of a connecting rod 10 and crank-shaft 12 journaled transversely
in the housings 31 31. Said connecting rod is fitted with a right and left screw-
threaded nut in order to render the length of the rod variable and so control the
stroke. The crank-shaft is fitted with a pulley 13 and driving belt loosely
thereabouts to some prime motor.
A prominent feature in this machine consists in the manner of mounting and
operating the hammer; in many instances in this type of machine the hammer is
rigidly affixed to the helve, while the latter is spring-actuated. In the present
instance this hammer is loosely attached to the free end of the helve and in the
following manner. This free end 15 of the helve is slotted vertically at 16 and
receives a rod 17, which plays loosely therein; moreover the hammer is apertured
to allow the free end of the helve to pass therethrough. Lateral ears or offsets 18
are cast upon the hammer head at each end and receive the extremities of the
rod 17, while encircling said rod are placed two coiled springs 19, 20, respectively
upper and lower, said springs rest upon washers 39, which serve as bearings against

page_text: the helve while the opposite bearings are supplied by the said ears 18. Thus it is
evident that the hammer has a certain freedom of movement independent of the
oscillations of the helve, which would otherwise occur if the latter and the hammer
were rigidly united.
Furthermore it will be noticed that the helve supports and actuates the hammer,
yet although said helve is a rigid bar at its free end by my method of mounting the
hammer a powerful and elastic blow may be imparted. To compel return of the
helve to its normal raised position, and to prevent a dead center upon the crank-
shaft I have flattened the fixed end of said helve and made a plate spring 23 thereof;
to increase the action of the said helve, a coiled spring 21 is located at the free end
and attached to the tie rod 6. In lieu of making the helve in one piece, as in
Fig. 1, a modified construction may be employed by making the spring portion 23
separate from the main part which consists of a rigid bar. This latter construction
simplifies the cost of manufacture.
To produce proper tension on the loose belt 14 about the pulley 13 I have
provided a belt-tightener in the shape of a rocker-arm 24, pivoted to the side of
one of the housings and equipped with a loose drum 25, adapted to contact against
the belt. The lower end of said lever is formed with a cam 26 and engages a
similarly formed extension 27, making part of a foot-lever 28 which spans the
front end of the machine to which it is pivoted; this form is to enable the operator
to work in various positions at the anvil and yet have full control of the hammer.
A spring 29 acts to hold the lever 28 in an upraised position, while a spring 30
serves a similar purpose with respect to the rocker-arm 24 aud pevents the latter
from touching the belt, except at proper times. The foot-lever is shown up-raised
and with the drum 25 in contact with the belt. The above described parts are
positive in their action, and no lost motion occurs, a great objection in the
operation of this class of machines where the strength of the blow should always be
under full control.
The operation of the hammer is as follows, it being understood that the rod 17
is free to move through the end of the helve, as well as lengthwise of the slot 16 to
compensate for the right line movement of the hammer and the oscillating motion
of the helve. Rotation of the crank-shaft causes oscillations of the helve; these
oscillations vary in rapidity, depending upon the length of the connecting rod,
while the power of the blow depends upon the tension of the belt 14; such tension
is varied by the operator at will through the agency of the foot-lever 28, its
extension 27 and the rocker-arm 24.
When a downward oscillation of the helve occurs the hammer drops quickly
therethrough, until it meets the object under treatment at this time the limit of
the oscillation of said helve has not been reached, as a result the lower spring 20 is
compressed and the effect of the blow is intensified as the two acts are almost
simultaneous. Immediately upon the beginning of an upward oscillation the lower
spring under compression and the upper under tension serve to accelerate the
movement of the hammer; for a moment such travel exceeds that of the helve. In
this manner a very quick spring blow follows the oscillation of the helve, which
act may be continued successively as with ordinary hammers of this class. By
mounting the hammer loosely upon the end of the helve this latter may be made
rigid and the amplitude of the oscillation be made to exceed the throw of the
hammer by means of the spring medium employed above and below the helve.
Thus not only is the blow elastic, but the hammer remains in contact with the
metal for the shortest space of time requisite to produce the desired effect.
By lengthening the oscillations of the helve and thereby increasing the
compression of the lower spring 20 the effect of the blow may be intensified.
In connection with this hammer and co-operating therewith is the anvil 4 placed
upon a cushion 38 and fitted for a removable face-block 35, the latter is secured in
position by a wedge or key and in the present instance acts as a matrix in
connection with a similar casting 36, as a die. This latter is adjusted above the
anvil proper and united with a matrix by a plate spring 37, which holds it in

page_text: position to allow of insertion or withdrawal of the metal in process. This form of
face-block is peculiarly adapted to drop forge work.
The hammer is equipped with a counter-shaft 31, supplied with emery wheels 40
and also with a blower 32, whereby a forge can be supplied with a forced blast;
thus tools in process may be ground and finished on the same machine.
I do not desire to be confined in my invention to a spring helve as it is evident
that a rigid helve may be employed and constructed as shown in Figure 3, viz.:
with the crank connection made at 41, and the fixed end to be secured at 42, the
rear end of the helves being shown by the dotted lines as extended to bring
the connecting rod about centrally thereof.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what I
claim is :
1st: In a power-hammer the combination with a suitable standard, its guides,
and an oscillating helve slotted at its free end, of an apertured hammer-head
adapted to reciprocate vertically in said guides and loosely of the helve, which
projects therethrough, a rod rigidly in said hammer-head but extending loosely
through the helve slot, and springs mounted on said rod upon opposite sides of the
helve, all operating substantially as set forth.
2nd: In combination with a standard having suitable guides, a helve movably
secured to said standard and slotted longitudinally at its free end, a rod extending
loosely through the helve-slot, an apertured hammer-head reciprocating in said
guides and having no positive connection with the helve which moves freely in
said aperture, spring mediums upon said rod on opposite sides of the helve, and
means for oscillating the helve, composed of a rotary crank-shaft, and a connecting
rod to the helve, substantially as stated.
3rd: In a power-hammer a suitable standard, the guides thereon, a spring
actuated helve slotted at its free end and secured to the standard by the spring 23,
a rotary crank-shaft, and connecting rod to oscillate said helve, combined with an
apertured hammer-head, mounted in said guides, springs interposed between the
ends of the hammer-head and opposite sides of the helve, a rod to hold said springs
in place and extending loosely through the slotted end of the helve, and the
balance spring 21, interconnecting the free end of the helve with the standard,
substantially as and for purposes explained.
Dated this 29th day of May 1893.