Improvements in Drop Hammers.
Year: 1888

page_text: Date of Application, 28th Dec., 1888
Complete Specification Left, 26th Sept., 1889-Accepted, 26th Oct., 1889
PROVISIONAL SPECIFICATION.
Improvements in Drop Hammers.
I, FRANK MCDOWELL LEAVITT, Vice President of the E. W. Bliss Company,
No. 17 Adams Street, Brooklyn, in the State of New York, United States of America,
Mechanical Engineer, do hereby declare the nature of this invention to be as
follows:-
This invention relates to drop hammers, or those in which a hammer is lifted and
then released and permitted to fall so that it strikes a blow proportional to the velocity
of its descent.
My invention provides a novel means for disengaging the lifting-gear and a novel
means for upholding the hammer. It also provides a novel construction of friction-
roller lifting-gear and a novel construction of hammer to he lifted by a friction-roller
lifting-gear.
The preferred lifting-gear for my improved hammer consists of oppositely arranged
continuously-revolving friction-rollers, adjustable toward and from each other, as here-
tofore, to engage between them or release the hammer, or an upright board or frame
attached thereto, which rollers, however, are pressed together by springs so that their
frictional engagement with the hammer is determined by the spring-pressure applied
to them. Toggle-levers or equivalent devices are employed to thrust them apart
against the spring-pressure in order to release the hammer."
My improved means for the automatic disengagement of the lifting mechanism from
the hammer is characterized by the employment of reciprocal wedging inclines, the
one carried by, or moving with, the hammer, and the other mounted on a stationary
part and arranged to be displaced by the moving incline upon the ascent of the hammer
to a predetermined height, and by its displacement to throw the lifting mechanism
out of action. Instead of two reciprocal inclines one incline and a parallel, or curved,
or other surface co-acting with it may be used.
My improved means for holding the hammer elevated consist of wedging inclines,
the one carried by the hammer and the other mounted on a stationary part, arranged
to wedge tightly together upon the ascent of the hammer to a predetermined point so
that by their wedging action a sufficiently intimate frictional engagement between
them is effected to uphold the weight of the hammer. Instead of two reciprocal
inclines one incline and a friction surface, such as a friction-shoe, may be employed to
like effect. Means are provided under the control of the operator for forcibly
separating said inclines in order to disengage and drop the hammer. The inclines
here referred to are, or may be, the same as those referred to in the preceding
paragraph for effecting the disengagement of the lifting-gear.
The remaining features of my invention will be described in detail hereinafter by
the aid of the accompanying drawings, wherein :-
Fig. 1 is a front elevation of my improved drop-hammer in its preferred
construction.
Fig. 2 is a right-hand side elevation thereof partly in vertical section cut in the
planes denoted by the lines 2-2 in Figs. 1 and 4.
Fig. is a left-hand side elevation thereof partly in vertical section cut in the
planes denoted by the lines 3--3 in Figs. 1 and 4.
Fig. 4 is a horizontal section in the plane of the line 4-4 in Fig. 1.
Fig. 5 is a fragmentary vertical transverse mid-section in the plane of the lines 5-5
in Figs. 1 and 4.
Figs. 6, 7 and 8 are side elevations of the hammer and the lifting, upholding and
disengaging gears, the frame being omitted.

page_text: Fig. 9 includes rear and side elevations of one size of friction-shoe, and a sid
elevation of another size thereof.
Figs. 10 to 12 are detailed views of the lifting-gear alone.
The remaining views illustrate modifications.
I will first describe the construction shown in Figs. 1 to 9 inclusive.
Referring to these figures, let A designate in general the fixed frame of the hammer
including the bed or anvil B and the two uprights or guide-pieces CC projecting
vertically upward therefrom. D is the hammer, which moves vertically between
the uprights CC, being guided by V-slide-ways thereon, as heretofore or other
wise. I have shown a hammer with a plain head a and a body b formed integrally
therewith, but obviously the construction of the hammer may be varied according
to any constructions heretofore employed. The body portion is made with parallel
front and rear faces to be engaged by the frictional lifting rollers E E, Fig. 6.
These rollers are fixed on shafts FF which are mounted in rotative bearings in
lever-frames GG pivoted respectively to the front and rear of the uprights CC by
pintles cc. These levers G G are drawn together by powerful springs S S, Figs. 2, 4
and 6, so that the rollers are forced into firm frictional engagement with the front and
rear faces of the hammer body b. One of the shafts F projects beyond its bearings at
its right-hand and the other at its left-hand end, and on their projecting portions are
fixed driving pulleys H H which are belted to a counter-shaft, as usual, so as to
be driven at equal speeds in opposite directions as indicated by the arrows in
Fig. 2.
Each of the levers G G carries a pair of friction shoes J J, one of which shoes
is shown detached in Fig. 9. These shoes are arranged to hear against the hammer
body outside of the parallel faces thereof, against which the friction-rollers bear.
This outer portion of the hammer body is formed with wedging inclines K K
on the front and rear sides thereof, as best shown in Fig. 3. The friction-shoes J.J
are loosely pivoted to the lever-frames G G so that they are permitted to adjust
themselves to parallelism with the inclined faces K K.
The operation is as follows:-Assuming the hammer to have fallen to the bottom
of the stroke its friction-rollers E E are drawn together by the tension of the
springs S S and engage the opposite faces of the hammer body with sufficient force
to enable them to propel it upwardly at a rapid speed so that it acquires considerable
momentum. When the ascending hammer approaches its highest position its
inclines KK which previously have moved freely between the shoes J J, as indi-
cated in Fig. 6, begin to wedge themselves against these shoes so as to force the
latter, and consequently the lever-frames G G, apart. The momentum of the hammer
is such that its upward movement continues in spite of the retardation due to engage-
ment with the shoes until the lever-frames G G are pressed sufficiently apart to move
the rollers E E out of contact with the parallel faces of the hammer-body, after which,
the momentum of the hammer being expended, it comes to rest. This pressing apart
of the friction-rollers EE enables them to continue their revolution freely without
grinding or chafing against the bammer-body. The friction between the faces of the
shoes JJ and the wedging inclines K K on the hammer is sufficient, consequent upon
the tension of the springs S S, to hold the hammer elevated, as shown in Fig. 7.
4
When the operator desires to drop the hammer be forcibly separates the lover-
frames G G still further than they have been separated by the action of the wedging
inclines, in order that the friction-shoes shall loosen their grip upon the said inclines
and enable the hammer to fall. To enable the operator to thus separate the frames G G
against the powerful pressure of the springs S S, I provide toggle links d d jointed at 50
their outer ends to the respective levers G G and engaged at their inner ends, or
knuckle-joint, by a pull-rod which extends downwardly and is connected to an
operating treadle T. The operator by pressing down on this treadle pulls downwardly
on the rod and thereby straightens out the toggle links d d, as shown in Fig. 8,
whereupon the hammer falls. If it is desired that the hammer shall instantly reascend, 55
the operator will release the treadle T immediately upon the striking of the hammer,

page_text: whereupon the latter reascends and remains suspended until the operator again
depresses the treadle.
Preferably, the rod f extending down about half way toward the treadle is jointed
(in Fig. 1) to a lever e to the end of which another rod f¹ is jointed, and this latter
rod extends down and is jointed at its lower end to the treadle-lever T. The lever e
is formed with an upwardly projecting arm e¹ which is engaged by a catch-lever g
which is pivoted to the right-hand upright C by a bolt or studi in such manner
as to be removable at will. When the operator depresses the treadle, the tilting
movement of the lover e brings its arm beyond the end of the catch-lever g,
whereupon the latter drops and prevents the lever e tilting back, so that the operator
may immediately release the treadle T. The lever-frames G G are thus held spread
apart until the hammer falls to the bottom of its stroke, whereupon an incline h
formed on the hammer-body and working against the tail g¹ of the catch-lever,
tilts the latter sufficiently to disengage the lever e, which consequently frees the
lever-frames GG, and the latter being instantly drawn together by their springs
cause the friction-rollers to engage with the hammer-body and quickly lift the
hammer again. This device insures the fall of the hammer until it strikes the blow
without necessitating that the operator shall hold the treadle depressed until the hammer
is fully down.
The pressure of the springs S S may be applied to the lever-frames G G at any
convenient point either above or below the axes of the rollers E E. The springs
might be connected directly as tensile springs in the manner shown in Fig: 13, but I
prefer to employ compression springs, as shown in Fig. 2. A yoke j is pivoted on a
pintle to one of the lever-fraines G and a bolt m is passed through the other frame,
its threaded end screwing into a cross-head n having notched ends engaging the sides
of the yoke. The spring S is compressed between the free end of the yoke and the
cross-head n, its tension being adjusted by turning the bolt m by means of its head
so that its threaded end draws the cross-head n toward the rear.
The friction-shoes J are preferably constructed as shown best in Fig. 9 with a cylin-
drical boss p which enters a semi-cylindrical seat or bearing recess 9 in the lever-
frame G, and is retained in place therein by a vertical pin ".
The height to which the hammer will ascend before it is stopped by wedging
between the friction shoes will be governed by the distance apart of these shoes rela-
tively to the thickness of the inclined portion K K of the hammer. The adjustment
of the drop of the hammer may consequently be effected by inserting thicker or
thinner shoes J J according as it is desired that the haminer shall ascend to a lesser
or greater elevation. In Fig. 9 the middle view shows a thicker shoe designed to be
substituted for the thinner one shown in the right-hand view when it is desired that
the hammer shall not rise so high. The same adjustment might be otherwise attained
as will be obvious to any mechanic, as for example, by inserting reinforce bushings
behind the half-round pivotal bosses p p of the shoes, or to the same effect by facing
the inclines K K with thickening plates.
Figs. 10, 11 and 12 show a detail of construction of the haminer-body b. The
hammer-body is faced on its opposite parallel sides with plates or boards ww of any
suitable material for affording a frictional surface against which the lifting rollers E É
may bear, such for example, as any suitable metal, or some fibrous composition, or
wood. These plates wo wo are preferably applied by being driven downwardly from
the top into undercut recesses formed in the front and rear faces of the hammer-
body, the shape of these recesses being best shown in Fig. 12.
The parts J and K might be transposed. That is instead of the inclines K K
being formed on the hammer they may be formed on the levers G G, and instead
of the shoes J J being carried by these levers or other stationary part they may
be carried by the hammer. Such a construction is shown in Fig. 14, where the
lever-frames G G are formed with two wedging inclines K K and the hammer D
carries friction-shoes J J pivoted to it on a stud p¹.
It is not essential that friction-shoes properly so-called shall be used as the part
of incline which reciprocally co-acts with the wedging inclines K K. In Fig. 13

page_text: I have shown a simple projecting block J carried by the hammer and entering
between the wedging inclines K K in order to force apart the levers G G. Fig. 14
shows a. modified method of spreading apart the levers G G upon depressing the
treadle, such method consisting of a lever-arm d hearing a wheel or roller and
to the projecting end of which arm the rod f is jointed. On pulling down this rod
the roller rolls against the face of the opposite lever G and forces the two levers
apart.
Fig. 15 shows how my invention may be applied to an existing construction of drop-
hammer of the type having a wooden board fastened to the hammer-head and pro-
jecting upward between the two friction-rollers. One of the friction-rollers is
stationary the other roller alone being moved toward or from it, motion being com-
municated to it by oscillating an eccentric bearing sleeve M which turns in bearings
in the supporting frame. There is only one wedging incline K, which is formed on a
separate piece or block L which is clamped or fastened to the upright board at any
desired point. A friction-shoe J is arranged to be displaced by this wedging incline
and is pivoted to an elbow-lever N against which a spring S presses in order to force
the shoe J toward the upright board of the hammer. A stop t is provided to limit the
movement of the lever N. This lever is connected by a link to a lever-arm v
projecting from the eccentric sleeve M. so that the latter is oscillated by the vibratory
movement of the lever N. When the hammer nears the top of its movement its
incline K encounters the shoe J and presses it outwardly, thereby tilting the lever N
against the tension of the spring S and also through the link u moving up the arm v
and oscillating the sleeve M in such direction as to move the movable friction-roller
sufficiently away from the immovable roller to release the hammer-board. The hammer
then remains suspended, held by the friction between the shoe J and incline K.
My invention inay be in part availed of by the employment of a partial equivalent
for the wedging inclines K K and shoes J J. Such a construction is shown in
Fig. 16.
In this figure the lever-frames G G are inverted, and their lower ends
carry toggle-arms which are normally held at the angle shown by stops a formed
on the lever-frames.. When the hammer. ascends shoulders y formed on it encounter
the free ends of these toggle-arms and form therewith a knuckle-joint forcing the
toggle-arms into a straight line in order to separate the levers G G and they may
move sufficiently beyond a straight line so that the opposite inclination of the toggle-
arms will suffice under the tension of the springs S S to hold the haminer
suspended.
Dated this 18th day of December 1888.
FRANK MCDOWELL LEAVITT.
J. C. Mewburn,
55 & 56, Chancery Lane, London, Patent Agent.
COMPLETE SPECIFICATION.
Improvements in Drop Hammers.
I, FRANK MCDOWELL LEAVITT Vice President of the E. W. Bliss Company,
No. 17 Adams Street, Brooklyn, in the State of New York, United States of America,
Mechanical Engineer, 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 drop hammers, or those in which a hammer is lifted and
then released and permitted to fall, so that it strikes a blow proportional to the
velocity of its descent. Such haminers have been heretofore constructed in which
the lifting mechanism consists of two opposite friction rollers revolving continuously
toward each other and engaging between them a board or upright attached to the
hammer or the body of the hammer itself, and by their tractive engagement therewith
lifting the hammer between them until disengaged therefrom by being moved apart.
My invention relates chiefly to hammers of this class,

page_text: In drop hammers the lifting mechanism by which the hammer is elevated is usually
thrown out of action automatically upon the hammer reaching a certain predetermined
height, the hammer being then in some constructions permitted to fall immediately,
while in others it is held elevated by means of a pawl or other device for preventing
its descent until, by the pressing of a treadle or operating lever, the upholding
device is retracted, whereupon the hammer falls. With both constructions it has
been usual to provide means for adjusting the lift of the hammer which shall dis-
engage its lifting mechanism, in order that the lift of the hammer and consequently
the force of its blow may be varied from time to time according to the kind of work
being done.
My invention provides a novel means for disengaging the lifting gear and a
novel means for upholding the hammer. It also provides a novel construction of
friction-roller lifting gear and a novel construction of hammer to be lifted by a
friction-roller lifting gear.
The preferred lifting gear for my improved hammer consists of oppositely arranged
continuously revolving friction rollers adjustable toward and from each other, as
heretofore, to engage between them or release the hammer, or an upright board or
frame attached thereto, which rollers, however, are pressed together by springs so
that their frictional engagement with the hammer is determined by the spring pressure
applied to them. Toggle levers or equivalent devices are employed to thrust them
apart against the spring-pressure in order to release the hammer.
My improved means for the automatic disengagement of the lifting mechanism
from the hammer is characterized by the employment of reciprocal wedging inclines,
the one carried by or moving with the hammer and the other mounted on a stationary
part and arranged to be displaced by the moving incline upon the ascent of the
hammer to a predetermined height and by its displacement to throw the lifting
mechanism out of action. Instead of two reciprocal inclines one incline and a parallel
or curved or other surface co-acting with it may be used.
My improved means for holding the hammer elevated consist of wedging inclines,
the one carried by the hammer and the other mounted on a stationary part, arranged
to wedge tightly together upon the ascent of the hammer to a predetermined point,
so that by their wedging action a sufficiently intimate frictional engagement between
them is effected to uphold the weight of the hammer. Instead of two reciprocal
inclines one incline and a frictional surface-such as a friction shoe-may be employed
to like effect. Means are provided under the control of the operator for forcibly
separating said inclines in order to disengage and drop the hammer. The inclines
here referred to are or may be the same as those referred to in the preceding para-
graph for effecting the disengagement of the lifting gear.
The remaining features of my invention will be described in detail hereinafter by.
the aid of the drawings which accompanied my Provisional Specification wherein
Figure 1 is a front elevation of my improved drop-hammer in its preferred construc-
tion. Figure 2 is a right hand side elevation thereof partly in vertical section, cut
in the planes denoted by the lines 2-2 in Figures 1 and 4. Figure 3 is a left hand
side elevation thereof, partly in vertical section cut in the planes denoted by the
lines 3-3 in Figures 1 and 4. Figure 4 is a horizontal section in the plane of the
line 44 in Figure 1. Figure 5 is a fragmentary vertical transverse mid-section.in
the plane of the lines 5-5 in Figures 1 and 4. Figures 6, 7 and 8 are side eleva-
tions of the hammer and the lifting, upholding and disengaging gears, the frame
being omitted. Figure 9 includes rear and side elevations of one size of friction-shoe
and a side elevation of another size thereof. Figures 10 to 12 are detail views of the
lifting gear alone, showing the improved construction of the hammer-upright,
Figure 10 being a front elevation, Figure 11 a vertical transverse mid-section, and
Figure 12 a horizontal transverse section of the upright. The remaining views
illustrate modifications. Figure 13 is a side elevation answering to Figure 7 and
showing a modified construction. Figure 14 is a similar side elevation showing
another modification. Figure 15 is a vertical transverse section showing a further

page_text: mominication.
cation.
Figure 1 is a fragmentary side elevation snowing another moum-
I will first describe the construction shown in Figures 1 to 9 inclusive.
Referring to these figures let A designate in general the fixed frame of the
hammer, including the bed or anvil B and the two uprights or guide-pieces CC,
projecting vertically upward therefrom.
Ď is the hammer which moves vertically between the uprights CC, being guided
by V-slideways thereon, as heretofore. I have shown a hammer with a plain head a
and a body b, formed integrally therewith; but obviously the construction of the
hammer may be varied according to any constructions heretofore employed, as, for
example, by connecting a die to the hammer head, or in place of the hammer head,
as is used for drop-forging and drop-stamping. The body portion b is made with
parallel front and rear faces to be engaged by the frictional lifting rollers E E,
Figure 5. This body portion 6 may be made integral with the hammer head, or it
may consist of a wooden board or metal plate fastened thereto as heretofore.
The friction lifting rollers EE are fixed on shafts F F, which are mounted in
rotative bearings in lever frames G G pivoted respectively to the front and rear of the
uprights CC by pintles c c. These levers G G are drawn together. by powerful
springs SS, Figures 2, 4 and 6, so that the rollers are forced into firm frictional
engagement with the front and rear faces of the hammer-body . One of the shafts F
projects beyond its bearings at its right hand end and the other at its left hand end,
and on their projecting portions are fixed driving pulleys H H which are belted to a
counter shaft as usual, so as to be driven at equal speeds in opposite directions, as
indicated by the arrows in Figure 2.
Each of the levers G G carries a pair of friction shoes J J, one of which shoes is
shown detached in Figure 9. These shoes are arranged just beyond the ends of
each of the friction rollers E E, so that they bear against the hammer body b outside
of the parallel faces thereof, against which the friction rollers bear. This outer
portion of the hammer body is formed with wedging inclines K K on the front
and rear sides thereof, as best shown in Figure 3, which is a section through the
portion of the hammer-body on which these inclines are formed. The friction shoes J.J
are loosely pivoted to the lever frames G G so that they are permitted a sufficient
degree of angular motion to enable them to adjust themselves to parallelism with the
inclined faces K K against which they bear.
.
The operation is as follows: Assuming the hammer to have fallen to the bottom
of its stroke, the friction rollers EE are drawn together by the tension of the
springs S S and engage the opposite faces of the hammer body with sufficient force
to enable them to propel it upwardly at a rapid speed, so that it acquires considerable
momentum. When the ascending hammer approaches its highest position, its
inclines K K which previously have moved freely between the shoes J J, as indicated
in Figure 6, begin to wedge themselves against these shoes so as to force the latter
and consequently the lever frames GG apart. The momentum of the hammer is
such that its upward movement continues in spite of the retardation due to engage-
ment with the shoes until the lever frames G G, are pressed sufficiently apart to
move the rollers EE out of contact with the parallel faces of the hammer-body,
after which, the momentum of the hammer being expended, it comes to rest. This
pressing apart of the friction rollers E E enables them to continue their revolution
freely without grinding or chafing against the hammer body. The friction between
the faces of the shoes JJ and the wedging inclines K K on the hammer is sufficient
consequent upon the tension of the springs S S to hold the hammer elevated, as
shown in Figure 7.
When the operator desires to drop the hammer, he forcibly separates the lever
frames G G still farther than they have been separated by the action of the wedging
inclines, in order that the friction shoes shall loosen their grip upon the said inclines
and enablo the hammer to fall. To enable the operator to thus separate the frames G G
against the powerful pressure of the springs S S I provide toggle-links d d, jointed

page_text: at their outer ends to the respective levers G G and engaged at their inner ends or
knuckle-joint by a pull-rod which extends downwardly and is connected to an
operating treadle T. The operator by pressing down on this treadle pulls down-
wardly on the rod and thereby straightens out the toggle-links d d as shown in
Figure 8, whereupon the haminer falls. If it is desired that the hammer shall
instantly reascend the operator will release the troadle T immediately upon the
striking of the hammer, whereupon the latter reascends and remains suspended until
the operator again depresses the treadle. If repeated falls of the hammer are desired
the operator will repeatedly depress the treadle, the hammer falling after each dopres-
sion thereof.
The connection of the rod to the treadle T just referred to may be a direct con-
nection if desired, but the indirect connection shown is preferable. Referring to
Figure 1 the rod extending down about half-way toward the treadle is jointed to a
lever e to the end of which another rod" is jointed, and this latter rod extends
down and is jointed at its lower end to the treadle-lever T. This intermediate lever e
not only increases the leverage against the rod but enables the rod f¹ and treadle T
to be carried out sufficiently to one side to avoid the base of the machine. This con-
struction has also another function,-The levor e is formed with an upwardly projecting
arm e which is engaged by a catch lever g which is pivoted to the right hand
upright by a bolt or stud in such manner as to be removable at will. The
hammer being elevated and suspended the operator depresses the treadle T and
thereby tilts the lever e sufficiently to release the hammer holding device and permit
the hammer to fall. This tilting movement of the lever e brings its arm el beyond the
end of the catch-lever, whereupon the latter drops and prevents the levere tilting
back, so that the operator may immediately release the treadle T. The lever
frames G G are thus held spread apart until the hammer falls to the bottom of its
stroke, whereupon an incline formed on the hammer body and working against the
tail of the catch lever, tilts the latter sufficiently to disengage the lever e, which
consequently frees the lever frames G G, and the latter being instantly drawn together
by their springs, cause the friction rollers to engage with the hammer body and
quickly lift the hammer again. This device ensures the fall of the hammer until it
strikes the blow without necessitating that the operator shall hold the treadle depressed
until the hammer is fully down, as would otherwise be necessary, because of the fact
that the springs S S will immediately bring the friction rollers against the hammer
body if left free to do so.
It is an important advantage of my invention that under no possibility can the
hammer fall while the machine is in operation until, by the depression of the treadle,
the friction rollers are forcibly separated. If the hammer in its ascent should have
insufficient momentum to wedge itself closely enough between the shoes JJ to
frictionally hold it suspended, so that it slips out from between them and begins to
descend, this movement brings the friction rollers E E together and into contact with
the hammer body, so that they lift it again and prevent its falling. If the hammer
should thus slip back the operator will know that the machine is running too slowly,
and he will accordingly speed it up faster in order that the hammer shall be lifted at
a greater velocity.
The pressure of the springs S S may be applied to the lever frames G G at any
convenient point, either above or below the axes of the rollers E E.
The springs
might be connected directly as tensile springs in the manner shown in Figure 13,
but I prefer to employ compression springs as shown in Figure 2. A yoke jis
pivoted on a pintle & to one of the lever frames G and a boit m is passed through the
other frame, against the exterior of which its head is seated, its shank passing through
an eye in the front end of the yokej, and its threaded end screwing into a cross-
head n having notched ends engaging the sides of the yoke. The spring S is com-
pressed between the free end of the yoke and the cross-head n, its tension being
adjusted by turning the screw m by means of its head, so that its threaded end draws
the cross-head n towards the rear.

page_text: The friction-shoes J are preferably constructed as shown best in Figure 9, with a
cylindrical boss p projecting on the side opposite to the frictional face, which boss
enters a semi-cylindrical seat or bearing recess y in the lever frame G, and is retained
in place therein by a vertical pin r, driven tightly through holes in the lugs above
and below the recess and entering loosely a hole s, formed vertically through the
boss p of the shoe, all as best shown in Figures 3, 6 and 9. Any other pivotal
connection for these shoes offering a sufficiently unyielding engagement with the
levers G G and allowing sufficient freedom of motion for the shoes, may be substituted
for the particular construction shown.
The height to which the hammer will ascend before it is stopped by wedging
between the friction shoes will be governed by the distance apart of these shoes
relatively to the thickness of the inclined portion K K of the hammer. The adjust-
ment of the drop of the hammer may consequently be effected by inserting thicker or
thinner shoes JJ, according as it is desired that the hammer shall ascend to a less or
greater elevation. In Figure 9 the middle view shows a thicker shoe designed to be
substituted for the thinner one shown in the right hand view when it is desired that
the hammer shall not rise so high. The same adjustment might be otherwise attained,
as will be obvious to any mechanic,-as for example, by inserting re-enforce bushings
behind the half round pivotal bosses p p of the shoes, or to the same effect by facing
the inclines KK with thickening plates. Any device which will change the relation
of the friction rollers E E to the inclines K K when the hammer is at the bottom of
its stroke will cause the disengagement of the friction-roller and the wedging fast of
the hammer to occur at a higher or lower point in the stroke.
Figures 10, 11 and 12 show a detail of construction of the hammer body b which
is omitted from the other Figures for the sake of clearness. The hammer body is
faced on its opposite parallel sides with plates or boards ww of any suitable
material for affording a frictional surface against which the lifting rollers E E may
bear, such for example as any suitable metal or some fibrous composition or wood.
These plates ww are preferably applied by being driven downwardly from the top
into undercut recesses formed in the front and rear faces of the hammer body, the
shape of these recesses being best shown in Figure 12. The plates should fit so
tightly as to prevent their displacement. If driven down until their lower ends
come in contact with the bottoms of the undercut recesses, they will have little or
no tendency to work upwardly out of place, since at each blow they will be driven
downwardly, and during the lifting movement the force pressing the rollers E E
together serves to press these plates with equal firmness against the intervening
solid portion of the hammer-body, thereby preventing their working upward. If,
however, some additional fastening is desired, screws may be employed, as shown
in Figures 10 and 11. The surface of each plate w exposed on the front or rear
of the hammer body should be of a width equal to the length of the roller, or
slightly in excess thereof, as shown in Figure 10. Outside of this width sufficient
space must be left for the undercut flanges by which the plate w is held and for the
wedging inclines K K.
In the description of my improved means for disengaging the lifting mechanism
and for holding the hammer suspended 1 have described the wedging inclines KK
as being formed on the hammer and the shoes J J as being carried by the lever
frames G G. These parts J and K might, however, he transposed, that is, instead
of the inclines being formed on the hammer they may be formed on the levers GG,
and instead of the shoes being carried by these levers or other stationary part they
may be carried by the hammer. Such a construction is shown in Figure 14, where
the lever frames G G are formed with two wedging inclines K K and the hammer D
carries friction-shoes J J pivoted to it on a stud P. Pins q¹ are arranged to limit
the vibratory movement of these shoes.
It is not essential that "friction-shoes" properly so called, shall be used as the
part or incline which reciprocally co-acts with the wedging inclines K K. In
Figure 13 I have shown a simple projecting block .J' carried by the hammer and