IMPROVEMENTS IN CARRIAGE JACKS AND OTHER LIFTING JACKS
Year: 1870

page_text: PROVISIONAL SPECIFICATION left by John Phillips Barford at the
Office of the Commissioners of Patents, with his Petition, on the
9th July 1870.
I, JOHN PHILLIPS BARFORD, of Banbury, in the County of Oxford,
Ironmonger, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN CARRIAGE JACKS AND OTHER LIFTING JACKS," to be as
follows:-
My Invention consists of the arrangement or combination of parts
herein-after described of carriage jacks and other lifting jacks whereby
the lifting arm of the jack is made to preserve a vertical position during
its motion and the fixing of the said lifting arm at the desired height
is effected by self-acting mechanism instead of by the ordinary cross
pin.
My improvements are particularly applicable to carriage jacks,
and I will describe them as applied to a carriage jack, but my said
improvements are also applicable to lifting jacks used for various
purposes.

page_text: The carrage jack consists essentially of a foot and forked upright, and
a lifting arm and mechanism for working and fixing the said lifting arm,
the said lifting arm and mechanism being capable of being raised and
lowered and secured at the proper height on the said upright. The
lifting arm of the jack consists of a vertical bar, the upper end of which
carries a seat, which is placed under the axle of the carriage to be lifted.
Nearly parallel with the lifting arm is a bearing plate provided with a
toothed quadrant. The handle or lever by which the jack is worked
passes through the forked upright, and the inner end of the said lever is
jointed to the lifting arm and to the bearing plate carrying the toothed
quadrant. The bottom of the lifting arm is jointed by a link to the
bottom of the said bearing plate. On the upper side of the handle or
lever is a jointed pall or click made to engage with the teeth of the
toothed quadrant of the bearing plate by means of a spring. The joint or
centre of the bearing plate on which the lever turns consists of a cross
pin, which said cross pin may be made to engage with a pair of a series
of pairs of inclined notches made on that side of the forked upright at
which the lifting arm is situated. When so engaged with the notches
the bearing is fixed to the upright, and the lifting arm and lever
are supported by the said fixed bearing plate, and the lever may be
depressed or raised for the purpose of raising or depressing the lifting
arm of the jack and the carriage axle under which the seat of the said
lifting arm is placed. As the handle end of the lever is depressed the
click or pall on the said lever slips over the teeth of the toothed
quadrant on the bearing plate, and when the carriage has been lifted to
the required height the lifting arm is fixed at that height by the said
pall engaging with the said quadrant. As the lifting arm is raised the
arrangement of joints described causes it to preserve a vertical position,
thus preventing the slipping of the axle from the seat of the said lifting
arm which frequently happens in the use of ordinary carriage jacks. To
depress the lifting arm it is only necessary to disengage the pall from the
toothed quadrant by means of a rod or wire on the handle or lever.
The said handle or lever may now be turned on its joint and the
lifting arm lowered.