Note: Descriptions are shown in the official language in which they were submitted.
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AN ADJUSTABLE, INSULATING PUSH ROD OR TRACK ROD FOR RAILWAY
POINTS
The present inve~tion relates to an adjustable, insulating
push rod or track rod for railway points in which, in the
middle area, there are two sleeves with internal threads,
into which sections of the push rods are screwed.
DE-PS 1 116 712 describes the use of push rods for a clam~
lock to transfer switching force to a pair of tongues of a
point, these being configured so as to be insulating. This
known configuration provides adjustability in that a middle
section that resembles a turnbuckle with opposing threaded
sleeves is provided and track rods or push rods can be
screwed into this from either end. In this known
configuration, the middle part incorporates the connector
lug for the point-setting drive. In this known
configuration it has been proposed that insulation be
achieved in that the sleeve thread be fitted in the middle
section as an insulating sleeve. These insulating sleeves
are subjected to compressive and tensile forces and there is
a danger that the sleeves as a whole can become loose during
vibration, when any previously made adjustments will be
lost. For this reason, there are limits to the amount of
force that can be absorbed by insulating bushes that are
pressed into blind bores in the middle part. A similar
configuration is described in DE-AS 1 279 711; in this, the
longitudinal bores are formed with a greater inside diameter
than the outside diameter of the threaded sleeves and a
composite outer layer o~ electrically insulating material is
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proposed as a filling for the threaded sleeves. In this
configuration, the insulating intermediate layers are
sub]ected to shear stresses in the axial direction which
means that in the course of protracted use during vibration
once again adjustment can be lost because of loosening.
In order to avoid an unfavourable application of force of
this kind onto plastic intermediate layers, DE-OS 2 239 493 -
proposes that the configuration be s~lch that the insulating
intermediate layers are subjected, as far as possible, to -~
pres~ure. To this end, the spacer that incorporates the -
attachment lug for the point-setting drive has two recesses
that are oriented in opposite directions and taper conically
to the outside, into which a threaded bolt with a
correæponding conical head can be introduced. The outer
edge of the bolt head is covered with insulating material
and the head of the connecting threaded bolt is drawn into
the conical recess of the spacer by tightening the push rod
sections, through an insulating intermediate layer. Even
though the intermediate layers of the face ends between the
partial section of the push rod and the middle piece are
subjected exclusively to compressiQn, and for this reason
are more favourably stressed, there are still shear forces
within the area of the head of the connecting bolt and this
canlsubsequ~ntly give rise to the need for readjustment.
Furthermore, in a configuration of this kind, assembly is
costly and the matching or formation of the conical areas in
the head of the connecting bolt can be problematic. If, as
is proposed in DE-OS 2 239 493 rotation is prevented by
means of a locating pin, which passes through a section of
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the connecting bolt and a partial section of the push rod,
and is screwed into the connecting bolt, this rotational
locking is confined to the prevention of rotation relative
to the connecting bolt that is held in place only by
friction and can, rotate within the conical recess of the
spacer of these frictional forces are overcome. If this
frictional or force fit between the connecting bolt and the
middle section is loosened, there is no prevention of
rotation relative to the middle part.
It is the task of the present invention to create the
configuration of an insulating push rod that is both simple
to produce and simple to assemble, in which the structural
elements can be used in the manner of a building block for
one embodiment of the push rod, with or without an
attachment piece for a drive rod, and simultaneously ensures
the prevention of rotation of the push rod sections relative
to the middle part and the parts of the middle part relative
to each other. At the same time, it is the object of the
present invention to ensure that the forces that occur as a
result of the individual parts of the push rod being
tightened against each other and which occur during
operations are confinad to insulating intermediate layers
exclusively in the form of compressive forces, which means
that the insulating materials will be subjected to less
wear.
,.
In order to solve this problem, the configuration of the
adjustable insulating push rod or track rod according to the
present invention is essentially such that the sleeves have
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on their inner face surfaces that are remote from the
unattached ends where the push rod sections are screwed in
at least one off-set anti-rotation bolt or threaded pin; and
in that the sleeves are connected in the area of the anti-
rotation bolt and/or connecting bolt by at least one off-
centre threaded pin or an additional connector bolt,
optionally with a middle piece for the attachment of an
operating rod, with interposed insulating inserts at the
face sides. Because of the fact that the sleeves have on
their inner face surfaces that are remote from their free
ends for the insertion of the part sections at least one
off-centre anti-rotation bolt or a threaded pin, when the
sleeves are fitted to a middle piece, which can be done
through an attachment piece for an operating rod or by the
direct assembly of two sleeves, it is ensured that the
sections of the middle piece do not rotate relative to each
other, when insulating inserts that are arranged between the
sleeves, optionally through a middle piece for the
attachment of an operating rod are subjected exclusively to
compression forces. Connection of the sleeves that have the
threads can be effected either by way of eccentric threaded
bolts or anti-rotation bolts in the manner of an eccentric
dowel with an additional connecting bolt, when the
insulation will have to be provided at the face ends in the
area of the anti-rotation bolt and/or the connecting bolt.
A particularly favourable absorption of force and a
particularly simple assembly results if as in a preferred
development, the additional connecting bolt is formed by an
essentially axial threaded pin. Given this sort of
configuration the track rod sections can be screwed securely
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into the threads of the sleeves, when the configuration can
be in the manner of a turnbuckle and in each instance
opposing thread directions can be used on each side. If
identical configurations for the track rod sections are to
be used as series parts, one of the two nut threads of the
sleeves must be con~igured as a right-hand thread, and the
other as a left-hand thread, when the insulated middle part
can be assembled in an appropriate manner. As an
alternative to the configuration with a locating pin and an
essentially central connecting bolt, the configuration can
be such that each of the sleeves has a flange that is remote
from the insertion end, and through which passes at least
one threaded bolt with interposed insulating inserts, in
which connection at the same time a particularly simple
assembly, once again optionally with an interposed middle
piece for an attachment from an operating rod is possible.
Here, too, during assembly and during operation, the forces
are absorbed essentially and exclusively as compressive
~orces, and this leads to a particularly long service life
and operating safety.
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Because of the fact that no additional insulating components
are required in the area of the screw thread of the sleeves, ;
additional security against rotation can be provided in a
par,ticularly simple manner. To this end, it is advantageous ;~
that the configuration be such that the part sections that
can be screwed into the sleeves each have at least one axial -~
groov~ or an axial bolt bore to prevent rotation. When this
is done, by offsetting a plurality of axial grooves or
radial bolt bores appropriately in the peripheral direction ;
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of the insertion end, it is possible to achieve
correspondingly precise adjustment even with a slight change
in the rotational direction for axial adjustment.
In a particularly advantageous manner, the configuration is
such that the connecting bolts are screwed in with the
insertion of pressure distri~uting washers against the
insulating inserts, which means that during assembly no
particular care has ~o be taken and the assembly can be
effected with conventional impact tools.
The push rod ends that are screwed into the threads of the
middle part that is configured as a turnbuckle can be
secured in the conventional manner by means of nuts and lock
nuts so that they cannot rotate relative to the middle
section for no additional insulation is required at this
point. ~ecause of the fact that insulating materials can be
avoided in the threaded sleeves themselves, not only is it
possible to provide for simple prevention of rotation by an
adjusting screw that fits in a groove that is essentially
axial, but adjustment without any additional checks to
ensure that the insulation in place is also possible.
The present invention will be described in greater detail
below on the basis of embodimènts shown diagrammatically in
the drawings appended hereto. In these drawings, figure 1 ;~
shows a first configuration of the middle piece with push
rods screwed into position without any interposed middle
piece for the attachment of an operating rod; figure 2 shows
a second configuration of a middle piece of this kind, in
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partial axial section; figure 3 shows a configuration with
sleeves as in figure 2, with an interposed intermediate
piece for the attachment of an operating rod, and figure 4
is a larger-scale drawing of the middle section as in figure
1 with an interposed middle piece for the attachment of an
operating rod, in partial axial section.
Figure 1 shows two sleeves 2, each of which has an internal
thread 1, and these are screwed together at their inner or
face ends that are remote from the insertion ends 3, through
insulating intermediate layer~ 4. Rotation is prevented by
using a locating pin 5, and the rigid connection of the two
sleeves is achieved by an essentially axial connecting bolt ::~
6. The axial connecting bolt 6 can itself be prevented from ~:
rotating, to which end there is a radial bolt bore 7 in :~
which an anti-rotation bolt fits. Because of the prevention
of rotation by the dowel or the anti-rotation bolt 5,
despite the prevention of rotation by the connecting bolt 6,
the rotational position is also fixed as a result of even a
slight contraction in the area of the insulation elements. ~ .
Push rod sections 8 are screwed into the insertion ends 3 of
the sleeves 2, with the two sleeves that are connected to .
each other being configured as a type of turnbuckle, so that
the axial length of the push rods can be adjusted~by
rotating the two sleeves. The bolts that are inserted in `~
the push rod sections 8 have radial grooves 9 in which anti~
rotation bolts 10 can fit, this then resulting in a
particularly stable and ~afe configuration. ~
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In the configuration that is shown in Figure 2, there are
once again two sleeves that are connected directly to each
other without the interposition of any spacer for the
attachment of an operating rod. The sleeves 2, whose
internal threads 1 are shown diagrammatically, have, in each
instance, a flange 13 on their inner sides that are remote
from the insertion ends 3, and a connecting bolt 12 passes
through this. In this case, too, the connecting forces are
absorbed by insulating inserts 4 between the face sides of
the sleeves 2, that are subjected only to compressive
forces; naturally, in the area of the connecting bolts 12,
the insulation has to be provided in the fonm of bushings
13. The bushings 13 incorporate annular flanges 14, and
pressure distributing rings 15 are installed between the
screw head and the annular flanges 14, so that the
insulation is not damaged during the installation process.
Only identical track-rod parts 8 and two identical sleeves
are required to assemble rods of this kind. In the event
that the sleeves are configured with a flange 11, rotation
is pre~ented by the plurality of off-centre connecting
bolts.
If, in addition, a spacer is to be used for attachlng an
operating rod, all that is reqiuired is an additional spacer;
no additional modification of the structural elements is
required.
If a sleeve 2 with a flange 11 is used, the configuration as
in Figure 3 is used. In this case, the spacer 16, which
incorporates the attachment point 17 for the operating rod,
also has two flanges 18 that are bolted to the flanges 11,
... .. ... , ... - .. , . , , , . : , . . ........................... .
.. , ~ . , . - . . , .. , . , . . . : . . . - ,
. .. .. , , .... ~: :. , . .. . ; ; - : . . . :
. ;., . ,. . . . - , ,,. , .... . .. , . . - . , ~ -, ~,- - . .
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using the threaded bolts 19. All of the same component
parts as in the configuration shown in Figure 2 are used,
and once again pressure distributing elements 5 are
installed between the head of the threaded bolts 19 and the
insulating annular flanges 14 of the insulating bushings 13.
. .,
If sleeves as shown in Figure 1 are used and an attachment
piece 20 for an operating rod is interposed, it is possible
to use the configuration as in Figure 4. Here, too, the
sleeves 2 as in Figure 1 are used, and in addition to an -
off-centre dowel 5 to prevent rotation, an essentially axial
connecting bolt is provided, and this is bolted directly to
the spacer 20 and the insulating layers 4. Once again the
spacer 20 has an attachment point 21 for attaching an `;~ ~-
operating rod. Identical parts are used in this
configuration, too, and only an attachment piece for the ;; ~;~
drive rod is added; otherwise the same parts as the
configuration shown in Figure 1 are used.
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As is shown particularly clearly in Figure 4, in order to
improve the insulating properties, the insulating
intermediate layers 4 can be so configured that they
incorporate annular extensions that overlap the outer sides ` ;`
of the sleeves 2 or the spacer 20; this makes it more
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difficult for moisture to penetrate into the area of the
insulating intermediate layers.
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