IMPROVEMENTS IN AUTOMATIC FRICTION CLAMPS OR BRAKES
Year: 1884

page_text: I HENRY WILLIAM JONES of Tenbury Villa 119 Herbert Road Shooter's Hill
Plumstead Kent Mechanical Engineer do hereby declare the nature of my Invention
for IMPROVEMENTS IN AUTOMATIC FRICTION CLAMPS OR BRAKES and in what
manner the same is to be performed, to be particularly described and ascertained
in and by the following statement and shewn in the accompanying Drawing:-
The Drawing is shewn to an enlarged scale of about twice full size as applied to
the tangent scale of a sight for ordnance. Fig. 1 is a side view, Fig. 2 is a front
view shewing part in section. Fig. 3 is a side view with the cover reinoved. Fig. 4
is a view of the interior of the cover shewing the inclined slots. Fig. 6 is a
sectional plan. The same letters refer to the same parts in each Figure.
A is the ordinary sight bar or tangent scale which may be made either square,
rectangular triangular or of any other sectional form. This bar is provided with a
rack gearing with a pinion B, C is the holder or buckle which is kept in its place
by means of the spring pin end of axle D which snaps into the recess in the body
of the gun E or sight carrier, and is easily withdrawn by pulling the wheel cover
at the opposite end compressing the spiral spring F. G is a loose collar, H is a
screwed nut to secure the spring in its place, I is a circular plate with a fixed
V grooved wheel. J. J is a double arm fixed to the axle and carrying with it
two cam shaped friction clips or pawls K K, L is a spring secured to the tail
piece M to ensure the clips being kept in contact with the groove. N. N are studs
or pins entering the slots OO of the cam plate R attached to the inside of the
cover P which forms part of the hand wheel or clamp box, and is milled on the
outer edge for facility of manipulation and is free to turn on the axle, but
controlled by the studs or pins N N. Q is a loose collar with a pin to secure it.
The action is as follows. The sight bar when adjusted for any desired elevation
acts by gravity on the pinion tending to run down, but the spring keeps the clips
in contact with the surface of the groove and they jam tightly from their eccentric
form, the greater the disposition of the bar to run down the more tightly does the
clip which restrains that direction grip on the other hand any movement of the bar
in the opposite direction due to a desire on the part of the bar to jump upwards
under the shock of discharge of the gun is immediately met and counteracted by
the opposite clip. In turning the wheel P in order to raise or lower the bar A the
clips K K are withdrawn or disengaged by the action of the slots OO of the cam

page_text: plate, which engage the studs N N and lift the two friction clips or pawls K K
and allow the pinion B to turn freely in either direction and thus to actuate the
bar A as required. Directly the hand is removed the clips are forced into 'the
groove by the spring L and are ready to clamp tightly the bar immediately it is
disposed to move either upwards or downwards under the shock of discharge of
the gun or any other influence apart from the legitimate motion of the hand wheel.
This brake can be applied to the elevating and traversing gear of gun carriages,
also to cranes and combinations of wheel work gearing.
Having now particularly described and ascertained the nature of this my said
Invention, and in what manner, the same is to be performed, I declare that what
I claim is 1 an automatic friction brake or clamp combined and contained within
a wheel box and consisting of one or more cam-shaped clips or pawls which engage
by frictional contact a circular V shaped groove and are actuated by inclined slots
and a spring or springs substantially as set forth.
2nd When used for ordnance sights the means of securing the buckle in its
place on the gun by a spring axle which snaps into a hole by the pressure of a
spiral spring and is easily released by pulling the hand wheel P which withdraws
the end of the pin D from its seat in the gun or sight carrier.
Dated this 20th day of June 1884.