IMPROVED FRICTION HAMMER
Year: 1885

page_text: "
I, CHARLES DENTON ABEL of No 28 Southampton Buildings in the County of
Middlesex, Consulting Engineer and Patent Agent do hereby declare the nature of
my invention for "IMPROVED FRICTION HAMMER 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 an improved construction of friction hammer which
I will proceed to describe with reference to the accompanying drawings, in which
Fig. 1 shews a side view and Fig. 2 a front view of the machine.
The wooden hammer stem b, carrying at its lower end the wrought iron hammer
block B is nipped between the plane surfaces of two friction discs a a¹ which are
either fixed upon two separate shafts capable of shifting longitudinally, or they
are arranged to revolve with, but to slide longitudinally upon a single shaft that
has no longitudinal motion. In either case the shaft or shafts carrying the friction
discs is or are driven by means of belt pullies while the friction discs are moved
together and apart by means of steering gear for .effecting the raising and lowering
of the stem and hammer.
The steering gear consists of the levers ii, whose fork-shaped ends embrace
collars on the friction discs. Between the lower ends h h of the said levers, which
may be provided with rollers, is situated a wedge-shaped piece g, so that by
moving this upward by means of the rod e the levers i have their upper ends
moved towards each other, whereby they are made to force the friction discs a a¹
against the hammer stem b. The wedge g is adjustable upon the rod e by means
of an adjusting screw and nuts, as shewn; the rod e is actuated by means either
of the hand lever c or the treadle c¹ for raising the wedge g and bringing the
discs a a¹ into action, the separating of these again being effected automatically by
the springs k and f. The lever c may be provided with an adjustable balance
weight so arranged that the lever is thereby caused to raise the wedge g sufficiently
to actuate the bammer. In order to prevent the hammer from being raised beyond
a certain height, the hammer stem is reduced in thickness at xx, as shewn in the
front and side view at Figs 3 and 4.

page_text: The highest position of the hammer stem will be determined by the extent of
the frictional surfaces of the discs acting upon the stem; as the part xx rises
between the discs, the surfaces in contact will gradually become less and less, until
eventually an equilibrium will be established, that is to say, the hammer will
remain suspended in a position in which the frictional contact between the discs
and stem will just balanco the weight of the hammer.
The rollers serve to guide the stem b. It will be seen from the section at
Fig. 5 that the latter is made thinner at the inner side; the object of this is to
limit the frictional contact between the stem and discs to the outer circumference
of the latter, whereby a more rapid motion of the bammer will be obtained than
would be the case if the contact extended'over the whole width of the stem. The
framing of the hammer may either be formed of wrought iron columns, as shewn,
or it may be made of a single casting of cast iron.
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
1. The construction of friction hammer wherein the hammer block B is raised
by the frictional contact between the hammer stem b and the outer circumferences
of the plane surfaces of the discs a a¹.
2. The use, in a friction hammer operating as set forth in the preceding claim
of a stem b, reduced in thickness at xx for regulating the height of stroke, and
also made of decreased thickness on the inner side in order to limit the frictional
contact to the outer circumference of the discs.
3. The use in a friction hammer operating as set forth in the first claim of
steering gear consisting of the levers ii springs and f rode and wedge g operated
by the lever c or treadle c' substantially as herein described.
1
T
1007