Improved Construction of Pinion-teeth.
Year: 1896

page_text: Date of Application, 16th Apr., 1896
Complete Specification Loft 14th
محل
1907 Accented
2016
Cab 4007
Date of Application, 16th Apr., 1896
Complete Specification Loft, 14th 120, 1907 Accepted, 20th Feb.,
1007
Improved Construction of Pinion-teeth.
I, CHARLES DENTON ABEL, of 28 Southampton Buildings, Chancery Lane, in the
County of London, Consulting Engineer and Chartered Patent Agent, do hereby
declare the nature of this invention to be as follows:-
This invention relates to an improved construction of the teeth of pinions, more
particularly those employed on rack-railways.
In order to prevent as far as possible the teeth of such pinions from mounting
the rack, and to assist them in entering the rack over the entrance tongue, especially
with regard to brake pinions under light carriages, the crown of the teeth is,
according to this invention, constructed of a rounded form instead of straight as
form instead of stra
Heleiviure.
The mode in which it is preferred to form such teeth is shewn on the
accompanying drawing, but the construction will of course vary according to
circumstances, in particular with regard to the diameter, pitch, and number of teeth
of the pinions.
In this figure, W represents the developing circle for the volute curve of the teeth
and X the pitch circle of the pinion. For designing the volute curve Y for the
flanks of the tooth, a line Z is first drawn representing the inclination (preferably
1:4) of the tooth of the rack bar, and which crosses the pitch circle X at B, and
at this point a perpendicular line is drawn which is a tangent to the developing
circle W, and at the meeting point b of the tangent with this circle is drawn a radius
which is parallel to the inclination of line Z.
The arc bA is then marked off on the developing circle, which arc is equal to
the tangent b B, and at equal distances, points c, d, e, are marked off on W, and
tangents C, d D, e E are marked, equal in length to the arcs, c A, d A, e A, the
points A B, C, D, E thus forming points for the volute curve Y.
For this volute curve is then substituted the arc of a circle commencing at the
point H and drawn with a radius of 66 nim., the point H being situated 13 mm.
inside the pitch circle X.
From the point J of the said arc, a smaller arc J K is drawn with a radius of
15 mm., and from the point K another are K L is drawn with a radius of 30 mm.
having its centre on the centre line V of the tooth. The bottom of the tooth,
between the points F and G is rounded off with a radius of 10 mm.
The configuration of one half of a tooth is thus obtained, represented by the
curve FGHJKL. The dimensions above given correspond to a pinion ring with
12 teeth of a pitch of 120 mm. and a radius U for the pitch circle of 229-2 mm.
In a similar manner the template for any other size of pinion can be drawn.
Dated this 16th day of April 1896.
ABEL & IMRAY,
Agents for the Applicant.

page_text: Improved Construction of Pinion-teeth.
I, CHARLES DENTON ABEL, of 28 Southampton Buildings, Chancery Lane, in the
County of London, Consulting Engineer and Chartered Patent Agent, 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 an improved construction of the teeth of pinions, more
particularly those employed on rack-railways.
In order to prevent as far as possible the teeth of such pinions from mounting
the rack, and to assist them in entering the rack over the entrance tongue, especially
with regard to brake pinions under light carriages, the crown of the teeth is,
according to this invention, constructed of a rounded form instead of straight as
heretofore.
The mode in which it is preferred to form such teeth is shewn on the drawing
accompanying my Provisional Specification, but the construction will of course vary
according to circumstances, in particular with regard to the diameter, pitch, and
number of teeth of the pinions.
In the said drawing W represents the developing circle for the volute curve of the
teeth and X the pitch circle of the pinion. For designing the volute curve Y for the
flanks of the tooth, a line Z is first drawn, representing the inclination (preferably
1:4) of the tooth of the rack bar, and which crosses the pitch circle X at B, and at
this point a perpendicular line is drawn which is a tangent to the developing
circle W, and at the meeting point of the tangent with this circle is drawn a radius
which is parallel to the inclination of line Z.
The arc 6A is then marked off on the developing circle, which arc is equal to the
tangent 6 B, and at equal distances, points, c, d, e, are marked off on W, and tangents
c C, d D, e E, are marked, equal in length to the arcs, c A, d A, e A, the points A B, C,
D, E thus forming points for the volute curve Y.
For this volute curve is then substituted the arc of a circle commencing at the
point H and drawn with a radius of 66 mm., the point H being situated 13 mm.
inside the pitch circle X.
From the point J of the said arc, a smaller arc J K is drawn with a radius of
15 mm., and from the point K another are K L is drawn with a radius of 30 mra.,
having its centre on the centre line V of the tooth. The bottom of the tooth,
between the points F and G is rounded off with a radius of 10 mm.
The configuration of one half of a tooth is thus obtained, represented by the
curve F G H J K L. The dimensions above given correspond to a pinion ring with
12 teeth of a pitch of 120 mm. and a radius U for the pitch circle of 229.2 mm.
In a similar manner the template for any other size of pinion can be drawn.
The accompanying drawing shews part of a pinion A whose teeth are formed with
rounded crowns, according to this invention, in gear with a rack B, X and X'
being respectively the pitch lines of the pinion and rack.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
1. The rounding off of the crown or top of the teeth of pinions used as working
or braking pinions in locomotives or other vehicles on rack railways.

page_text: 2. A pinion for use on rack railways, the crowns or tops of whose teeth are-
rounded off by means of curves, substantially as herein described.
1007
ABEL & IMRAY,
Agents for the Applicant.