TECHNICAL FIELD The present invitation relates to a current collector shoe for sliding contact with an electric power rail, in particular for a railway vehicle, comprising a wear sole holder and multiple wear soles, which adapt to the rail contact surface.

Due to adaptation of wear sole the collector shoe maintain sliding contact with the power rail and increases the mating surface compared to collector shoes generally used. Multiple wear soles are to minimize electrical wear of collector shoe and power rail especially under rail vehicle acceleration condition but also considered to reduce abrasion under all other operation conditions.

BACKGROUND OF THE INVENTION Generally collector shoes for railway made of a single piece of cast iron, which cannot adapt to power rail sliding surface.

An improvement of foresaid collector shoe is use of carbon instead of cast iron. The advantage is less abrasive wear due to material properties, but not by improving rail adaptation or increasing mating surface. Power rail and collector shoe are considered to become a match under operation condition because of corresponding wear pattern. For that reason collector shoes are seldom changed even under non-satisfaction operation.

From mathematic point of view a plane is totally defined by three points.

Considering the projected contact area of two electric contact planes 21 and 22 the two contact planes touches each other at three real contact points 31731", 32732" and

33733". The space coordinates of each contact plane then already well defined. It is not restricted in terms of a plane, but also to any other three-dimensional surface.

From a microscopic view the contact plane surface of a collector shoe is more like a rock mass. The three highest peaks (or couple of peaks) touches each other and result in three single contact points. Regarding a 2-dimensional sectional plane two contact points 25 and 26 define two of three space coordinates.

Obviously under real conditions, high pressure will result in material deformation respectively peak deformation and will create a certain contact area 36, 37and 38.

Increasing pressure will result in increasing contact area and improves electrical contact in terms of higher conductivity.

Regarding a collector shoe the slider is able to touch the power rail at three points most. However the sliders are mechanically mounted to the collector shoe gear having two degree of freedom (42, 43) or one degree of freedom (43) at all. The theoretical number of contact points is limited to two respectively to one only.

Numerous inventors apply for patent to increases the number of contact points by forming teeth of a comb as regarded each teeth or pin correspond to one single contact point. It is regarded to improve the contact status or prevent a certain good contact status as long as possible, especially for being employed with potentiometer or other industrial use (see US Patent Application 2005/0013050).

However this will not work for power rail collector shoe as the slider moves over rail gaps of a few millimetres for example at rail joints or to bridges distances of up to 200 mm at rail expansion joints at high speed and under heavy rail conditions as dust, dirty, rain, snow or ice, etc.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide a collector shoe which wear sole adapts to the power rail and increases the mating surface even after change of collector shoe or wear pattern and to minimize abrasive and electrical wear under all rail operation condition.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is a front view of a power rail and a collector shoe. FIG. 2 is a 3-dimensional view of a collector shoe.

FIG. 3 is a side view of a collector shoe.

FIG. 4 is a front view of a collector shoe.

FIG. 5 is a bottom view of a collector shoe.

FIG. 6 is a front view of a collector shoe. FIG. 7 is a 3-dimensional view of two contact planes.

FIG: 8 is a 3-dimensional view of two contact planes of FIG. 7 after disconnection.

FIG. 9 is a sectional drawing through two of three contact points of FIG. 7.

FIG. 10 is a 3-dimensional microscopic view of a contact plate after removal of the other contact plate.

FIG. 11 is a side view of a collector shoe gear.

FIG. 12 is the front view of collector shoe gear as shown in Fig. 11.

FIG. 13 is a bottom view of collector shoe as claimed.

DETAILED DESCRIPTION OF THE PREFFERED EMBODIMENT

FIG. 1 shows a power rail (3) top contacted by a collector shoe. Foresaid collector shoe comprise multiple wear soles (2) embedded and assembled in a wear shoe holder (1). The electric power is picked up by wear soles (2) from top surface of power rail.

In FIG. 2 shows a 3-dimensional view of a collector shoe with three side by side wear soles (2') of overall length of collector shoe.

FIG. 3 shows a side view of another collector shoe having five wear soles (2") consecutively in the train moving direction. The wear sole holder (1") is bent longitudinal to create a spring-load under operation conditions.

FIG. 4 shows the same collector shoe as shown in FIG. 3 but in front view. The wear sole holder (V") is additionally bent transversal to the train direction.

FIG. 5 shows another collector shoe in bottom view. Multiple wear soles (2) well-positioned longitudinally and transver sally. Contact face of wear soles (2) are of rhomboid shape. The pattern of wear sole (2) consequently leads to a rhomboid shape of wear shoe holder (1) as well. The wear shoe holder (1) has a lateral flange bent down used for assembling the collector shoe to the third-rail shoe gear.

FIG. 6 shows a similar collector shoe as shown in FIG. 4 in front view. Between the wear shoe holder (1) and the wear soles (2) a visco-plastic layer (6) is integrated for shock absorbing reasons and proper adaptation to any slightly unevenness of power rail running surface to increase the mating area between the wear sole respectively all wear soles of the collector shoe and the power rail surface.

FIG. 7 shows two connecting planes (21) and (22). Their space coordinate are defined by three contact points (31, 32, 33). FIG. 8 illustrates foresaid connecting planes (21, 22) and corresponding contact points (31731", 32732" and 33733") after being disconnected.

FIG. 9 shows a microscopic cross section of the two planes (21, 22). The plate surfaces of both plates are more like a rock mass which touches each other at points (32'") and (33'"). Both points also define two space coordinates of the plates. FIG. 10 shows contact areas (36, 37, 38) as plastically formed under compression of both plates under real conditions. The contact areas are not necessarily plan but depend on the hardness and structure of the peaks, for example (27', 27").

FIG. 11 shows a principal side view of collector shoe gear as normally used. A collector shoe (50) is pushed vertically (43) on top of the power rail by a certain spring-load. However due to its construction collector shoe gears generally used are limited to vertical adjustment (43) only, but not allowing collector shoe (50) to adapt power rail by degree of freedom (42) or/and (41) as shown in FIG. 12.

FIG. 13 shows a claimed collector shoe from bottom view with certain wear sole pattern. To achieve multiple contact points between collector shoes and power rail it is claimed to segment the collector shoe (50) into multiple wear soles (2).

Each wear sole should be at least two to three times longer as a rail gap at rail joints for easily bridging the gap. A wear sole holder (1) connecting wear soles (2) to a stable unit should be able to bridge longer gaps up to 200 mm as required for expansion rails.

However to insure foresaid requirements but improve the overall electrical contact it is claimed to segment collector shoe to increase the number of contact points from theoretically one to at least three each wear sole, as regarded to be the theoretical maximum. For ensuring that, each wear sole (2) is mounted to the wear sole holder (1) respectively the wear sole holder (1) to the collector shoe gear in such a way that the wear sole holder (1) may additionally adapt flexible to power rail surface within designed flexible structure and/or the wear soles (2) itself have three degrees of freedom to adapt to power rail surface due to be flexible connected with the wear sole holder (1). What is new is to provide a contact area can be adapt to power rail area to ensure maximum contact area but also provide a sliding area instead of improve contact by multiple pins each of one contact point but not providing sliding properties and less abrasive wear under railway operation.

It should be obvious from the foregoing that various modifications may be made within the scope of this invention without departing from the appended claims.