Railway switches and signals – Switches – Sliding
Reexamination Certificate
2001-12-20
2003-09-09
Morano, S. Joseph (Department: 3617)
Railway switches and signals
Switches
Sliding
C246S448000
Reexamination Certificate
active
06616105
ABSTRACT:
BACKGROUND
This invention relates to a switch lock according to the features described in the preamble of claim
1
.
Various types of switch locks are already known from practice, such as hook locks, clamp locks, inside locks and latch locks. A common factor in all types of switch locks is the fact that they operate the switch tongues in changeover operation. The switch lock here ensures that the switch tongues are held in their final positions, namely with the closed switch tongue held so that a wheel flange cannot enter between the stock rail and the closed switch tongue, and the open switch tongue held so that the distance between the stock rail and the open switch tongue guarantees that the wheel flange can run through it without being hindered. Additional requirements and properties of the switch lock usually include the fact that the switch lock
includes a lock to prevent a gap between the stock rail and the switch tongue;
holds the switch tongue and stock rail on the lower flange of the rail even when the track gauge widens, so that the defined switch tongue gap is not exceeded;
permits longitudinal expansion of the switch tongue up to ±25 mm without any negative effect on secure locking;
can be used for electrically controlled switches as well as manual and trailable switches;
can be driven on at speeds up to 40 km/h;
can also be used together with a non-drivable switch operating mechanism;
can be used as a center lock for long switch tongues in high-speed switches;
fits all the usual Vignol rail profiles;
will function even in a dirty environment, snow drifts and ice, and
can be installed between two railroad ties or in a hollow railroad tie.
The latch lock is one type of switch lock that is often used in practice. The latch lock consists of a slide rod, a connecting strap, two locking latches, two switch tongue attachments and two locking pieces. The locking latches are installed in the switch tongue attachments which are fastened to the switch tongues. The locking pieces clamped onto the stock rails serve as a support for the slide rod. This construction allows migration of the switch tongue in the case of a thermally induced length change of ±25 mm. The lateral guidance of the slide rod is taken over by the switch tongue attachment. The locking latch is mounted with an eccentric bolt which allows for play in the switch tongue to be adjusted. The impacts caused by high forces acting on the latch axis are absorbed in a built-in elastic bushing. The slide rod has two slide rod parts which are electrically insulated in the middle, so that no short-circuit is caused with a built-in track direct current circuit. The drive rod usually acts in the middle, but a lateral action is also possible.
The following applies with regard to the mode of functioning for switch changeover of the lock. The locking latch, connected indirectly to the switch tongue by means of the switch tongue attachment, passes beneath the lower flange of the rail and thus establishes the mechanical frictional connection. In a locked position, the locking latch snaps directly onto the locking piece and is secured in its position fixedly by the slide rod. The switches are switched due to the movement of the slide rod. The open switch tongue begins to move first. After traveling the unlocking distance, the latch is pulled downward, thereby initiating the unlocking of the closed switch tongue. After being completely unlocked, both switch tongues simultaneously follow the movement of the slide rod until the previously open switch tongue is closed. When the slide rod is pulled further, the latch is raised into its locked position. The switch tongue, which is now open, moves further until the changeover operation is concluded and it is secured in this position.
The wheel flange exerts a force on the open switch tongue when driving over the switch. If the construction of the switch operating mechanism allows, the slide rod is moved and the closed switch tongue is unlocked before following the movement of the slide rod. In this way, the switches can be driven on at speeds of up to 40 km/h without any damage from the wrong side.
It is disadvantageous in all the known types of switch locks that relatively high actuating forces are necessary for control operations. Control operations may result in actuating force peaks which can even result in damage to the switch lock. In addition, the known types of switch locks are often very susceptible to longitudinal movements of the switches. Another disadvantage is that the known types of switch locks have very high service and maintenance requirements. Since the individual parts of the switch lock which are movable relative to one another can be displaced onto one another, constant high lubrication is necessary to permit displaceability with even low actuating forces. Finally, the known types of switch locks offer very little possibility of adjustment to permit adaptation to certain installation situations.
SUMMARY OF THE INVENTION
The object of the present invention is to make available a switch lock of the type defined in the preamble, wherein only low actuating forces, which are also essentially constant, are required, and wherein the maintenance and lubrication expenses are minimized.
The object defined above is achieved with a switch lock of the type defined in the preamble according to this invention with the characterizing features of claim
1
. The design according to this invention differs greatly from the types of switch locks known in practice. Use of at least one bearing roller and direct or indirect rolling of the slide rod on the bearing roller leads at least essentially to only rolling friction occurring between the parts of the switch lock that can move relative to one another. Thus, in contrast with the state of the art, there is no sliding friction. As a result, the actuating forces required for control operations are not only relatively low but are also comparatively constant, so that the force peaks which occur in the prior art cannot occur here. In addition, the service and maintenance expense is very low due to the special design having the slide rod rolling directly or indirectly on the bearing roller. Constant lubrication over a large area is not necessary.
Although the design according to this invention can be implemented only in the area of a locking piece in the case of a switch lock, it is especially preferred for the invention to be implemented on both locking pieces of the switch lock. Accordingly, the following discussion with regard to the first or one locking piece should be understood to always also apply to the second or other locking piece, even if this is not mentioned specifically.
It is essentially possible to implement the special type of adjustment of the switch lock with a reduced switch tongue impact in comparison with the adjustment path of the slide rod by means of various movement possibilities and means or devices. In the embodiment according to this invention, the use of an angle lever for locking and/or adjusting the switch tongue which rolls on the bearing roller is preferred. To do so, the angle lever is connected in an articulated manner to both the slide rod and the switch tongue attachment. Indirect rolling of the slide rod on the bearing roller occurs by means of the angle lever which works directly with the bearing roller. Due to the articulated connection of the angle lever to the slide rod and to the switch tongue attachment, the switch lock according to this invention runs very smoothly and does not have any parts that slide against one another, except for the hinge switches of the angle lever and the bearing of the bearing roller. The angle lever is designed and connected in such a way that in adjustment of the slide rod, it pivots about the articulation point on the switch tongue attachment with its free end during locking or in the locked state of the switch tongue.
In this context, it is a special advantage that the angle lever has a first running surface of the rail facing downward on its free en
Böcker Jens
Grunwald Dieter
Collard & Roe P.C.
McCarry, Jr. Robert J.
Schreck-Mieves GmbH
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