Patent Publication Number: US-6220173-B1

Title: Trolley for rail tracks that are branched by means of switch points

Description:
TECHNICAL FIELD 
     The invention concerns a trolley—switch point configuration. 
     BACKGROUND OF THE INVENTION 
     Railway vehicles of any kind, particularly passenger trains, freight trains, electric trolleys for transportation inside of closed spaces such as production halls, sorting stations or high shelf storage, whether suspended or on the ground, must be routed in the desired travel direction via rail tracks that are branched by means of switch points. 
     Switch points that are equipped with moveable rail parts are known; they can be inserted into a gap in one or the other railway direction for deflecting or shifting. The power required to move the rail parts is considerable. Beyond that, wear in conjunction with the effect of weather and contamination are a disadvantage. Such mechanical, i.e. active switch points require intensive maintenance. Their use in explosion-proof and wet spaces is almost impossible and is not permitted in most areas. 
     So-called turntables are also known, in which the railway vehicles or individual railway cars are turned around with the turntable until a seamless transfer is established to the desired connecting track direction. In this case the fairly considerable power requirement is also a disadvantage. The danger of a switch point jam must also be considered. Railway vehicles or trolleys which closely follow each other can jam at the branch sections, since the operation of the turntables, as well as the above-cited deflecting switch points, require a long time for each vehicle. The trolleys must stop or at least slow down in any event. This very much restricts the passage of trolleys, i.e. the traffic density. 
     SUMMARY OF THE INVENTION 
     The object of the invention is to improve a trolley-switch point configuration in regard to power consumption, maintenance requirement, trolley passage and wear as well as contamination. It must further be endeavored to provide unrestricted access to explosion-proof and wet spaces. 
     The invention achieves this object by a trolley for rail tracks that are branched by means of switch points, wherein the trolley has moveable hooks, and the switch points are designed as passive switches without any moveable parts, where the hooks can engage the guide rails of the passive switches in accordance with the desired travel direction. The basic idea of the invention is to interchange the fixed and moveable components of the trolley and the switch points needed to pass through the branches. This provides the possibility of creating constructions which are characterized by very little power consumption, smooth passage through the branches without any stopping or braking phase, and low wear as well as a significant decrease in the required maintenance. 
     The invention also illustrates constructions that have advantageous further developments of the basic idea for an electric ground trolley (EBB) and an electric suspended trolley (EHB). In that case the passive switches are designed as a slotted hollow profile and provided with the guide rails, while the hook discussed above is designed as a rocker both ends of which are able to alternatively engage one of the two guide rails. The guide rail and the rocker may be located inside the hollow profile. This produces an effective protection against mechanical damage and contaminative as well as environmental influences. Such electric trolleys (EBB and EHB) are especially designed for use in workshops. However, their use for passenger and freight traffic is also conceivable. This allows the omission of heated active switches and their expensive control devices, which must comply with high safety standards. It is only necessary for the electric or diesel locomotive to have a device that engages a passive switch guide rail in a way so that the locomotive and all of its coupled cars are forced into the desired direction. However the following configurations refer only to the electric ground trolley and the electric suspended trolley for industrial applications, while their exemplary nature is emphasized. 
     Configurations are also illustrated for electric suspended trolleys that have advantageous designs which are characterized by good stability and friction properties. The guide rod or the holding device can pass through the longitudinal slot in an almost contactless manner. 
     It is preferred to control the position of the rocker by means of contactless inductive power transfer heads. This gives an advantageous smoothness to the rocker movements. The power demand of the electric ground trolley or the electric suspended trolley is also covered in a contactless manner by the inductive power transmission. 
     The travel direction can be established by controlling the switch points, as is the case with conventional switches. However no moving parts are required within the switch point. The moving part is the rocker, which is a component of the electric ground trolley or the electric suspended trolley. 
     Trolleys with a preprogrammed travel destination can establish the travel direction immediately before a branch. This variation is especially advantageous with trolleys following closely behind each other, which do not travel in accordance with a time schedule, but detect advancing trolleys by means of distance sensors for example, and autonomously compute the optimum routes for reaching a predetermined target point by means of an intelligent logic. Such systems are very flexible and can be used to advantage for example in assembly lines which process large lot sizes. 
     The free ends of the rocker can be provided with guide wheels to enable quiet and low friction shunting at branch points. In that case the guide wheels are used as quasi-hooks. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention is explained in greater detail in the following by means of two figuratively illustrated embodiments, where: 
     FIG. 1 a  is a cross section of the essential components of an electric ground trolley (EBB) in conjunction with a branch point; 
     FIG. 1 b  is a schematic top view of a branch point; 
     FIG. 2 a  is the same as  1   a  but for an electric suspended trolley (EHB); 
     FIG. 2 b  is the same as  1   b  but for an electric suspended trolley (EHB). 
    
    
     BEST MODE FOR CARRYING OUT THE INVENTION 
     FIG. 1 a  illustrates the lower part of an electric ground trolley EBB  1  interacting with a branch area  2  of a rail track arrangement  3  (See FIG. 1 b ). The rail track arrangement  3  is essentially designed as a hollow profile  4  with a longitudinal slot  5  on top. A guide rod  6  of the EBB  1  penetrates into the longitudinal slot  5 , and is connected on the top to an undercarriage axle  7 , and on the bottom to a support bearing  8  and a rocker  13 . The undercarriage axle  7  connects two drive wheels  9  to each other, which are able to move on both sides of the longitudinal slot  5  on the top  10  of the hollow profile  4 , and cause the EBB  1  to move forward. The support bearing  8 , for example a ball bearing, interacts with the inside  11  of two guide rails  12  of the hollow profile  4 . The guide rails  12  penetrate into the hollow profile  4  on both sides of the longitudinal slot  5 . Under the guide rails and the support bearing unit  12 / 8 , the rocker  13  is located above an axis of rotation  14  which is connected to the guide rod  6 . The free ends  15  and  16  of the rocker  13  have upwards facing guide wheels  17  and  18  installed on them. They are able to engage the guide rails  12 , depending on the position of the rocker  13 . In the position illustrated in FIG. 1 the right guide wheel  18  is engaged, which causes the EBB  1  to veer to the right. In the other rocker position, where the left guide wheel  17  on the free left end  15  is engaged, the EBB  1  in FIG. 1 b  would continue to travel straight on the rail track arrangement  3 . The rocker  13  is controlled by two mirror-symmetrical inductive power transfer heads  20 , which are located in the lower part of the hollow profile  4  opposite the free ends  15  and  16  of the rocker  13 . Depending on the electrification of the two power transfer heads  20 , either the left free end  15  or the right free end  16  of the rocker  13  is attracted, so that the respective other free end with the corresponding guide wheel  17  or  18  engages one of the guide rails  12 . on the outside  19  of the two guide rails  12 . Additionally, the inductive power transfer heads ( 20 ) can be controlled by an intelligent logic  30  which is integrated in the trolley and which is able to compute an optimum trajectory. 
     The same rocker principle is provided for the electric suspended trolley EHB  21  illustrated in FIGS. 2 a  and  2   b.  It can be seen that in the illustrated position of the rocker  13 , the EHB  21  is driven to the right and thus into a right turn. A modified hollow profile  22  is attached to a ceiling structure  23 . In addition to the rocker  13  and the inductive power transfer heads  20 , the hollow profile  22  also contains the drive wheels  9  of the EHB  21 . The top of the undercarriage axle  7  is connected to the axis of rotation  14  of the rocker  13 , and the bottom to a holding device  24  which penetrates into the longitudinal slot  5 , for a not illustrated cargo to be transported. In the same manner as the guide rod  6  of EBB  1 , the holding device  24  of EHB  22  is equipped with a support bearing  25 , which contacts a neck-shaped extension of the longitudinal slot  5 . 
     The invention is not limited to the embodiments indicated above. Rather a member of variations can be envisioned in which other basically different configurations utilize the features of the invention.