Improvements in Overhead Lines of Electric Railways or Tramways.
Year: 1897

page_text: Date of Application, 22nd Oct., 1897
Complete Specification Left, 22nd July, 1898-Accepted, 3rd Sept., 1898
PROVISIONAL SPECIFICATION.
Improvements in Overhead Lines of Electric Railways or Tramways.
I, PHILIP DAWSON, of 39, Victoria Street, in the City of Westminster, Civil
and Electrical Engineer, do hereby declare the nature of this invention
to be as follows: -
My invention relates to improvements in overhead lines of electric railways or
tramways and has for its object to provide an improved movable frog for use
with the overhead conductors or trollies used with such lines where a trolley is
required to pass from a single track to one of two or more tracks leading to any
particular district.
According to my invention I form grooves for the flanges of the trolley wheel
in the body of the casting constituting the frog and I provide slots in the said
grooves at the points through which moveable blocking pieces mounted on the
arms of a rocking lever can be caused to pass alternately so that the said pieces
form the bottom of a groove in one position and block up the groove in the
other position. By working the rocking lever by hand or otherwise one set of
grooves are thus blocked and the other set opened so as to form a branch line
from the main line, a spring or counterweight being preferably used for returning
the blocking pieces to their normal position.
With the aforesaid moveable frogs I may use flanges moveable or fixed on each
side thereof to act as leaders. One of the line wires is preferably led into the
guides on the frog, being secured thereto by sweating or by set screws, the other
passing across in a slot or groove formed on the back of the frog, and held in
position without appreciable bending or kinking by tongue pieces. The guides
into which take the grooves of the trolley wheels are preferably formed radial so
as to secure smoothness in running.
100%
JOHNSONS & WILLCOX,
47, Lincoln's Inn Fields, London, W.C., Agents.
COMPLETE SPECIFICATION.
Improvements in Overhead Lines of Electric Railways or Tramways.
I, PHILIP DAWSON, of 39, Victoria Street, in the City of Westminster, Civil
and Electrical Engineer, 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:
-
My invention relates to improvements in overhead lines of electric railways or
tramways and has for its object to provide an improved moveable frog for use
with the overhead conductors or trollies used with such lines where a trolley is
required to pass from a single track to one of two or more tracks leading to any
particular district.

page_text: According to my invention I form grooves for the flanges of the trolley wheel
in the body of the casting constituting the frog, and I provide slots in the said
grooves at the points through which moveable blocking pieces mounted on the
arms of a rocking lever can be caused to pass alternately so that the said pieces
form the bottom of a groove in one position and block up the groove in the
other position. By working the rocking lever by hand or otherwise, the grooves
of one set are blocked and those of the other set are opened so as to form a
branch line from the main line, a spring or counterweight being preferably used
for returning the blocking pieces to their normal position.
With the aforesaid moveable frog I may use flanges moveable or fixed on each
side thereof to act as leaders, one of the line wires is preferably led into the
guides on the frog being secured thereto by sweating or by set screws the other
passing across in a slot or groove formed on the back of the frog and held in
position without appreciable bending or kinking by tongue-pieces. The guides
into which take the grooves of the trolley wheels are preferably curved so as to
secure smoothness in running I will describe my invention by reference to the
accompanying drawings in which
Figures 1 and 2 are plans of respectively the under and upper sides of one form
of my improved adjustable or moveable frog and
Figure 3 is a transverse section of the same on line 3-3 of Fig. 1.
Like letter of reference indicates like parts throughout the drawings.
I form the improved frog of a plate A of brass or similar metal having at its
underside guides or ribs A¹ A2 along which travel the flanged trolley wheels
which are not shewn in the drawings. The guides or ribs A1 A3 at, or near the
junction point are found of less depth than at the ends of the frog so as to allow
the flanges of the trolley wheels to engage with grooves a formed at the central
part of the plate A on either side of the said guides or ribs. By these means the
trolley wheel which, in the ordinary way, travels along the guide or rib A at the
end of the frog shewn at the left hand of Figures 1 and 2 is directed with more
certainty than has hitherto been possible with other arrangements, over the
junction point and on to either of the branches A¹ A³. To afford additional
security against the trolley wheels leaving the guides or ribs A¹ A2, I provide
the plate with downwardly-depending flanges or guards a¹ which, by acting on
the casing in which the trolley wheel is mounted, serve to direct the trolley in the
proper direction.
I form slots or openings at in the before described grooves a at, preferably
the outside of the points as Figure 1 for receiving moveable blocking pieces d d
pivotted to the arms of a rocking lever I which is itself pivotted to a bracket A'
secured to the top of the plate A as shewn clearly in Figure 3. I prefer to
provide the rocking lever D with an arm d by which through a cord or equivalent
attached thereto it may be moved in one direction on the pivot d³ a counter-
weight or the equivalent thereof such as a spring, serving to move the
rocking lever in the opposite direction back to its normal position.
By working the rocking lever D in this manner the blocking pieces dd¹ are
withdraw from, and passed into and through the grooves a each serving to either
form practically a continuation of the bottom of the groove to which it appertains,
or to block up the said groove and project beyond it so as to enable it to act on
the trolley head and thereby assist in directing the trolley wheel in the desired
direction. By these means the trolley wheel travelling in the direction in-
dicated by the arrow in Figure 1 may be caused to run on to either of the
branches A¹ A2 by withdrawing the blocking pieces d or d from the groove a
adjacent to the particular branch along which it is desired the said wheel shall
travel.
Hitherto it has been usual to construct frogs for use in electric tramways or
railways with straight branches and with these it has been found that the com-
paratively sharp bends given to the trolley wires where they are connected to
these branches frequently cause the said wires to break at those parts. To over-

page_text: come that difficulty I curve the branches in the manner shewn in Figure 1 so
as to reduce the angle to which the trolley wires require to be bent, this improvement
also serving to turn the trolley wheels gradually instead of abruptly as has
hitherto been the case where the frog branches have been straight, and thereby
reducing the shock transmitted to the trolley mechanism.
Instead of cutting the main line of trolley wire and sweating or soldering the
two severed ends to the ends of the frog plate A as has hitherto been necessary
I prefer to arrange the frog so that it may be fixed in position without removing
or cutting or appreciably bending or kinking the said wire. For this purpose I
form a groove a² in the top of, and extending throughout the length of the
plate A and down into the guide or rib A' and sweat or solder the continuous
or main line of trolley wire in this groove and hold, or clamp it in the bottom
thereof by tongue pieces or dogs C¹ inserted into the groove and retained therein
by cross-pins C the set screws c¹ of the dogs C₁ in conjunction with the pins
and serving to give the necessary pressure on the trolley wire, the end of the
branch trolley wire is secured in the groove a³ in a manner similar to that
described in connection with the securing of the main trolley wire in the groove a².
By these arrangements the frog may readily be applied to an existing trolley wire
system without appreciably disturbing the latter.
C
Although for the purposes herein before described I prefer to form the frogs
with curved branches, may apply my improvements to frogs having straight
branches and I may modify the construction of my improved frogs in other ways
without departing from the essential features of the invention.
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 combination with a frog for overhead conductors of electric railways
or tramways having grooves for engaging with and guiding the flanges of the
trolley wheels, of moveable blocking pieces capable of being inserted into or
withdrawn from the said grooves substantially as and for the purpose hereinbefore
described with reference to the accompanying drawings.
2. The combination with a frog for overhead conductors of electric railways or
tramways having grooves for engaging with and guiding the flanges of the
trolley wheels, of moveable blocking pieces capable of being withdrawn from the
grooves so as to leave the passage therethrough unobstructed, or moved so as
to block and project out beyond the grooves substantially as and for the purpose
herein before described with reference to the accompanying drawings.
3. The combination with a frog for overhead conductors of electric railways or
tramways of a moveable guard and means for adjusting it so that it may be caused
to direct the trolley in a given direction substantially as herein before described.
4. The combination and arrangement of parts constituting the adjustable or
moveable frog for use in connection with conductors of electric railways or tram-
ways substantially as herein before described & illustrated in the accompanying
drawings.
1000
JOHNSONS & WILLCOX,
47, Lincoln's Inn Fields, London, W.C., Agents.