Year: 1899

page_text: Date of Application, 9th June, 1899-Accepted, 23rd Sept., 1899
I, HEINRICH HOFFMANN, of 45, Dewerthstrasse, Elberfeld, in the Empire of
Germany, Machine Constructor, 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 for an improved safety apparatus for tramway cars relates to a
guard or apparatus for preventing obstructions from getting underneath the
wheels.
As compared with similar apparatus already known, the present one has the
advantage that but a slight pressure is necessary against the guard-board in
order to set the rail guard in action and that the rail guard upon two pawls
being put out of engagement, falls directly by its own weight on to the track,
so that any loss of time between the contact with the guard-board and the falling
of the rail guard is avoided.
The invention is illustrated in the accompanying drawings in which
Fig. 1 is a side view of the safety apparatus applied to a vehicle and shown in
the normal or inactive position.
Fig. 2 is a similar view showing the apparatus in action.
Fig. 3 is an inverted plan of the safety apparatus and Figs. 4 and 5 are detail
views showing the rail guard holder.
At the sides of the carriage body a carriers b 61 are arranged which carry
the bearing arms c c in which the guard board d is pivotally suspended. To
the carriers 6 the rail guard e is also suspended, in such a manner that when
in the position of rest it is held hanging above the rails, as shown in Fig. 1.
This is effected as follows:-The rail guard is connected in a suitable manner
with an arm pivoted in the forked bearing g arranged on the carriage body a
and the free end of which arm is held in the highest position by means of two
pawls h h¹.
In order that the arm f may slide without hindrance out of engagement with
the pawls, and be easily put into engagement with the same, the free end of the
said arm is made in the form of a rhomb in cross section.
The prompt falling of the arm f, and a strong pressing action thereof on the
rail guard e is assured by means of the weight i arranged on the arm.
The pawls h h are retained in the locking position by the bar 7 supported
above the arm f and guided in the hoop bearing k, the said bar being guided
between the upper free ends of the pawls h h and pressing the pawls apart so
that they are held in the vertical locking position as shown in Fig. 4.
For the purpose of throwing the pawls out of the locking position, the dis-
engaging bar is pulled back. In order to prevent too great friction, roller
guides m m are arranged on the free ends of the pawls and in order that the
disengaging of the pawls h h¹ may be effected when the bar is pushed slightly
back, the bar is tapered at the end as shown.
The prompt throwing out of engagement of the pawls, as soon as the bar Z

page_text: is drawn back, is facilitated by the springs n n¹ arranged to act on the pawls as
soon as the counter pressure exercised by the rod 7 ceases to force them apart
from one another.
The disengaging bar is actuated by the guard board & on which a gripper p
is provided for this purpose, and as soon as the guard board is brought into the
vertical position through coming into contact with some obstacle, acts on an
extension or additional piece arranged on the disengaging bar and presses the
bar forwards.
In order that the guard board may be kept in the normal position when there
is no impediment in the way and to prevent any unintended sliding forward of
the disengaging bar 1, the pawl lever r is provided, this lever being furnished
at the front and back ends with incisions or recesses s s¹, in which the coupling
and uncoupling contrivance t arranged on the guard, board, and the locking pin
arranged on the disengaging lever rest when the pawl lever is in the horizontal
position.
The action of the above described safety apparatus is as follows:
As soon as any obstacle comes into contact with the guard board & the board
is swung backwards in the direction of the arrow. Upon this movement taking
place, the coupling contrivance acts on the pawl lever r, raising the same,
whereby the locking pin is set free. Simultaneously, the gripper p acts on
the extensions of the disengaging bar and pushes the bar forwards in the
direction of travelling. In consequence of this, -the-disengaging bar leaves its
position between the pawls h which as the pressure previously bearing on
them is hereby removed, are drawn away from one another by the springs n n
and set free the arm f that owing to its weight and the weight of the rail
guard e, falls and thereby presses the rail guard directly on to the rails, the rail
guard pushing aside-the-obstacle-lying in front of it.
As the sliding forward of the disengaging bar and the falling of the rail
guard e are effected almost at the same instant in which any obstacle comes into
contact with the guard-board d, it can be' seen that the obstacle constantly comes
between the guard-board d and the rail guard e. It is thus impossible that any
contact of the wheels with the obstacle lying beneath the vehicle can occur, and
thus any "running over "is certainly avoided.
In order that the rail guard when lowered may not be raised in consequence of
any unevenness of the road, it is advisable to arrange an india-rubber pad or
collar on its lower edge, so that even a person lying under the vehicle could not
put his hand beneath the rail guard.
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:-
-
The improved safety apparatus for street tramway cars, with moveable guard
board, the distinguishing feature being that, by the swinging back of the guard-
board d, a gripper parranged thereon, moves a disengaging bar in the direction
of travelling, whereby, at the same time, two pawls are thrown out of
engagement, and release the arm flying between them and carrying the rail
guard e, so that the rail guard is lowered on to the rails, when
obstacle comes
into contact with the guard-board d.
Dated this 9th day of June 1899
any
WHEATLEY & MACKENZIE,
40, Chancery Lane, London, W.C., Agents.