IMPROVEMENTS IN AND APPERTAINING TO MACHINERY FOR CUTTING THE TEETH OF WHEELS AND OTHER LIKE PURPOSES
Year: 1879

page_text: PROVISIONAL SPECIFICATION left by William Phillips Thompson at the
Office of the Commissioners of Patents on the 1st May 1879. A commu-
nication from abroad by the Firm of Messieurs L. Bénier et Cie., of Levallois-
Piret, Seine, France.
WILLIAM PHILLIPS THOMPSON, of the Firm of W. P. Thompson, and Co., of 6,
Lord Street, Liverpool, in the County of Lancaster, and 323, High Holborn, in the
County of Middlesex, British and International Patent Agents and Consulting
Engineers. "IMPROVEMENTS IN AND APPERTAINING TO MACHINERY FOR CUTTING
THE TEETH OF WHEELS AND OTHER LIKE PURPOSES." A communication from
abroad by the Firm of Messieurs L. Bénier et Cie,. of Levallois-Piret, Seine,
France.
This Invention has for its object a machine to dress the teeth of wheels, racks,
etcetera, cheaply and well.
The distinctive and essential characteristic of this machine consists in the mode
of operation upon the teeth instead of their being filed and planed. In fine to
obtain this result it is necessary that the tool in cutting follows the profile of the
teeth, and that whatever the form of curve adopted to determine this profile the
tool shall always be brought back at one arc of a circle and to one radius. It is
then indispensable that the tool in its cutting follow that radius and that are of a
circle, of which the centre and the radius are variable for each curve. My process
presents the advantage of reducing notably the price of truing up the dressing of
teeth, and in simplifying the work. In this machine as at present constructed a
cutting tool is mounted on the extremity of a grooved sliding bar possessing, as in
the slotting machine, a rectilinear alternating movement which is impressed upon
it by a connecting rod actuated by a disc or other crank which is keyed at the
extremity of a vertical shaft, which in turn receives its motion from the main
horizontal driving shaft, which is furnished with a fly wheel and driving cone. The
grooved sliding bar is supported by two lugs of a casting which rests upon a
pedestal in such a manner as to be able to swing or rotate upon its vertical axis.
This circular movement is necessary in cutting bevel wheels.
The wheel for cutting is mounted on a horizontal shaft, hereafter called the
mandril shaft, which is supported by two pedestals; these pedestals each rest upon
gantries, upon which they can be slid. Their position on the gantries can be
regulated to suit the wheel to be cut as it is larger or smaller. To resist the

page_text: pressure of the tool the wheel ought to be supported near its circumference. A shaft
with bearings in the two lugs supporting the slide carries at its extremity a point
which catches in a centre-punch hole in the middle of the tooth. This point is not
in the axis of the shaft; it is placed eccentric at such radius as to allow the shaft
to take a half turn, and while engaging the point in the same hole to bring the two
faces of the tooth to the same height, and in the horizontal plane passing through
the axis of the wheel. The tool mounted thus at the extremity of the slide has the
faculty of taking, besides the reciprocating movement communicated by the slide,
the following movements:-
1st. A circular movement.
2nd. A rectilinear horizontal movement.
3rd. A rectilinear vertical movement.
By means of machinery somewhat similar to those on a slide rest of an ordinary
lathe, the tool is fixed in the tool carrier which rests by its two trunnions upon
a block. This block can slide without the action of its hand wheel upon the slide,
and gives the tool the rectilinear horizontal movement which is utilized for planing
the part of the tooth bounded by the radius.
This horizontal slide rests upon a carriage mounted upon a block which is fixed
upon a toothed segment, which engages in turn in a circular groove of the sliding
carriage sliding in the vertical groove on the end of the main horizontal slide first
described. The slotted segment takes a circular movement independently of the
action of its worm. The point of the tool then describes an arc of a circle, of
which the centre is the same as that of the circular groove. In order to bring this
centre into a convenient position the last mentioned sliding carriage is made to
rise or descend by the action of a vertical screw. Bolts serve to fix the sliding
carriage rigidly against the end of the main slide when its centre is brought into
the required position.
As for the radius of the are of the circle described by the pointed tool it can be
varied by a screw which approaches or recedes from the centre point in causing
the first mentioned carriage to traverse. The tool can in consequence follow
exactly the arc of the circle which forms the profile of the tooth. A bar is bolted
to a projection on the carriage on one side of the tool, and serves as a fulcrum for
the same.