Connector for electrically coupling two current contact line segments in end-to end relationship

A connector for coupling two contact line segments positioned in end-to-end alignment and made of elongate plastic profiles for accommodating current conductor rails which cooperate with a current collector vehicle traveling inside the contact line segments, includes a coupling sleeve made of plastic material for positively enveloping the contact line segments in an area of their confronting ends, with the ends of the contact line segments being freely shiftable in a longitudinal direction within a predetermined range. The coupling sleeve is split in a direction transversely to the longitudinal direction so as to define two sleeve members which are detachably connected to one another, wherein one of the sleeve members can be placed on one of the confronting ends of the contact line segments and the other one of the sleeve members can be placed on the other one of the confronting ends of the contact line segments, before the contact line segments are joined.

CROSS-REFERENCES TO RELATED APPLICATIONS
 This application claims the priority of German Patent Application, Serial
 No. DE 198 07 792, filed Feb. 19, 1998, the subject matter of which is
 incorporated herein by reference.
 BACKGROUND OF THE INVENTION
 The present invention relates to a connector for coupling two contact line
 segments placed in end-to-end flush disposition and made of elongate
 profiles of plastic for accommodating current conductor rails which
 cooperate with a current collector traveling inside the contact line
 arrangement.
 A publication, issued by the company Akapp and entitled "Multiconductor"
 discloses a current contact line arrangement which is comprised of
 separate contact line segments of pre-assembled lengths that are joined
 together by coupling sleeves. The contact line segments are made of
 elongate profiles of plastic to form a casing for receiving the current
 conductor rails. The placement of the contact line segments inside the
 coupling sleeves is realized in such a manner that the end faces of the
 confronting elongate plastic profiles and the end faces of confronting
 conductor rails abut one another in end-to-end disposition. The difference
 of the thermal expansion coefficients between conductor rail and plastic
 casing is compensated by expansion joints which are spaced apart at
 certain distances. The expansion joints are so configured that the
 elongate plastic profiles are in alignment at a distance from one another
 within each expansion joint. The differences in expansion encountered
 between the elongate plastic profiles during temperature fluctuations and
 added up along several contact line segments is thus compensated by the
 expansion gap formed by the expansion joints.
 A drawback of this contact line arrangement is the need for separate
 expansion joints and the requirement to particularly design current
 collectors for traveling over the expansion gap, i.e. the current
 collectors must be designed of greater length and/or include an additional
 pair of wheels. Moreover, additional mountings and guides for the elongate
 plastic profiles become necessary.
 Brochures published in 1997 and in 1996 by the company Paul Vahle GmbH &
 Co. KG and entitled "Sicherheits-Schleifleitungen" and
 "Sicherheits-Schlelfleitungen--MKL", respectively, describe the use of
 expansion pieces for compensating varying length expansions. These
 expansion joints are utilized in addition to coupling sleeves which join
 together the pre-assembled contact line segments. Also disadvantageous in
 these configurations is the need for the use of expansion pieces spaced
 from one another at defined distances.
 From a brochure published in 1993 by Mannesmann Demag Fordertechnik AG and
 entitled "Kompakt-Kleinschleifleitung DKK", it is also known to use an
 expansion joint for contact line segments which are made of elongate
 plastic profiles and accommodate the current conductor rails and the
 current collectors of vehicles traveling in the plastic profiles.
 Confronting ends of the contact line segments are rectilinear in the
 transition zone and arranged in spaced-apart flush disposition. Moreover,
 the confronting ends of the contact line segments are provided with a
 funnel-shaped attachment to ensure a passage of the collector vehicle from
 one contact line segment to the succeeding contact line segment. The
 funnels of confronting ends of contact line segments are mirror images of
 one another and are spaced at a distance of few centimeters to compensate
 temperature-based length changes of the elongate plastic profiles. The
 distance between the funnels is so selected as to ensure a passage of two
 linked collector vehicles, with the funnels serving as guide for the
 linked collector vehicles on the inlet end. A drawback of this type of
 connector is the need for interrupting the conductor rails for safety
 reasons and the fact that only linked collector vehicles are able to pass
 the expansion gap.
 SUMMARY OF THE INVENTION
 It is thus an object of the present invention to provide an improved
 connector for coupling two contact line segments placed in end-to-end
 disposition, obviating the afore-stated drawbacks.
 In particular, it is an object of the present invention to provide an
 improved connector for coupling two contact line segments placed in
 end-to-end disposition, which is free from any distortions and
 deformations despite varying thermal expansion coefficients between metal
 and plastic, in particular PVC.
 These objects, and others which will become apparent hereinafter, are
 attained in accordance with the present invention by providing a coupling
 sleeve of plastic material for positively enveloping the contact line
 segments in an area of their confronting ends, with the ends of the
 contact line segments being freely shiftable in a longitudinal direction
 within a predetermined range, wherein the coupling sleeve is split in a
 direction transversely to the longitudinal direction so as to define two
 sleeve members which are detachably connected to one another, whereby one
 sleeve member can be placed on one of the confronting ends of the contact
 line segments and the other sleeve member can be placed on the other one
 of the confronting ends of the contact line segments, before the contact
 line segments are joined.
 A connector in the form of a coupling sleeve in accordance with the present
 invention meets all safety aspects as the conductor rails extending
 through the contact line arrangement are covered by the coupling sleeve
 and thus made inaccessible from outside in the transition zone between the
 contact line segments. The ability of the elongate plastic profiles inside
 the coupling sleeve and/or of the coupling sleeve to freely move in
 longitudinal direction ensures that no mechanical warping or deformation
 occurs even when the thermal expansion coefficients between the metallic
 conductor rails and the elongate plastic profiles vary significantly.
 The present invention is thus based on the teaching to provide a connector
 which not only reliably couples the current contact line segments but also
 compensates for expansions so that the need for separate expansion pieces
 or expansion joints, as typically incorporated conventionally and arranged
 in spaced-apart relationships inside the contact line segments, is
 eliminated. As a consequence of a detachable connection between the sleeve
 members of the coupling sleeve, the sleeve members can be placed over the
 confronting ends of the respective contact line segments before the
 contact line segments are joined together so that the contact line
 arrangement can be pre-assembled with the sleeve members. Thus, the sleeve
 members with attached contact lines can easily be joined to one another on
 site, e.g. by simply pushing the sleeve members together.
 According to another feature of the present invention, the sleeve members
 of the coupling sleeve are so configured that their confronting end faces
 at the longitudinal edges of the sleeve members abut one another, thereby
 ensuring a complete protection from touching the required electrical
 contacts as the conductor rails are completely screened to the outside.
 Suitably, in particular for reasons of stability, the longitudinal edges of
 one of the sleeve members extend tangentially relative to the longitudinal
 edges of the other one of the sleeve members.
 According to another feature of the present invention, the two sleeve
 members are provided with complementary locking elements which so interact
 with one another as to realize the detachable connection between the
 sleeve members.
 According to still another feature of the present invention, the sleeve
 members of the coupling sleeve have outwardly directed cambers in the
 coupling zone between successive sleeve members, with cambers of the
 sleeve members accommodating connecting assemblies for the conductor rails
 to thereby ensure a proper connection of the conductor rails.
 Suitably, each of the elongate plastic profiles is formed with an oblong
 hole of predetermined length at its ends, with the coupling sleeve being
 formed with an inwardly directed protrusion for engagement in the oblong
 hole. As a consequence of this type of interlocking engagement, the ends
 of the elongate plastic profile cannot be pulled out from the coupling
 sleeve during operation.
 A sufficient securement of the coupling sleeve can be realized by mounting
 both sleeve members at the conductor rail connecting assembly. Preferably,
 the conductor rail connecting assembly is so configured as to form a stop
 for the ends of the elongate plastic profiles.
 In order to realize a smooth passage of the current collector vehicle along
 the contact sleeve, the elongate plastic profiles define an interior space
 which is formed in the longitudinal direction with a running surface for
 operation of the current collector vehicle, with the running surface being
 formed with a slot extending in the longitudinal direction in the end zone
 of the elongate plastic profiles and being at least partially filled by a
 bar which is formed on the coupling sleeve, wherein the plastic profiles
 are longitudinally displaceable with respect to the bar, and the bar
 exhibits a top side facing the current collector vehicle and extends flush
 with the plane of the running surface.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
 Throughout all the Figures, same or corresponding elements are generally
 indicated by same reference numerals.
 Turning now to the drawing, and in particular to FIG. 1, there is shown a
 top, side perspective view of a coupling sleeve according to the present
 invention, generally designated by reference numeral 1 and connecting two
 successive contact line segments, generally designated by reference
 numeral 2 and provided in the form of elongate plastic profiles 3. The
 coupling sleeve 1 is made of plastic and split transversely to the
 longitudinal direction of the contact lines 2 so as to define two sleeve
 members 1 a which are of substantially identical configuration to form a
 casing which envelopes in a form-fitting manner the inserted confronting
 ends of the contact line segments 2 to be connected. The sleeve members 1a
 are detachably mounted to one another by a locking mechanism in the form
 of complementary locking elements 11 (FIG. 3) and 11a (shown in FIG. 2 by
 way of undercut), positioned laterally on the side walls of the sleeve
 members 1a. In this manner, both sleeve members 1a of the coupling sleeve
 1 can be detachably connected to one another by a suitable tool.
 As will be described in more detail furtherbelow, the plastic profiles 3
 are freely movable in longitudinal direction inside the coupling sleeve 1
 in a predetermined range. The ends of the elongate plastic profiles 3 are
 received in flush engagement in the area of the coupling sleeve 1, with
 same plastic profiles opposing one another.
 The sleeve members 1a are formed on the top surface and opposite side walls
 with outwardly directed cambers 9 and in immediate proximity to their
 longitudinal edges 1b in the area between the cambers 9 on the side walls
 and between the cambers 9 on the top surface with flanged sections 1c.
 Thus, the sleeve members 1a define confronting end faces 8 which closely
 abut one another when assembling the coupling sleeve 1, whereby the
 longitudinal edges 1b of one sleeve member 1a extend tangentially to the
 longitudinal edges 1b of the other sleeve member 1a, i.e. that the outer
 walls of both sleeve members 1a extend at the juncture of the end faces 8
 parallel to the longitudinal direction of the contact line and thus have a
 common tangent.
 The elongate plastic profiles 3 and the coupling sleeve 1 are formed on
 their bottom side with a longitudinal opening 4. In the installed stage,
 as shown in FIG. 1, the openings 4 of the plastic profiles 3 and the
 coupling sleeve 1 are in alignment to thereby form a continuous slot for
 feedthrough of a collector cable (not shown) of a current collector
 vehicle or trolley which travels on wheels 12 (FIG. 3) in the contact line
 arrangement 2 in longitudinal direction during operation, with the
 collector cable being connectable to an external current consumer.
 Turning now to FIG. 2, there is shown a top, side and front perspective
 view of a sleeve member 1a of the coupling sleeve 1 of FIG. 1 in
 conjunction with an elongate plastic profile 3 to illustrate in more
 detail the interior thereof. Each plastic profile 3 is formed with
 substantially C-shaped anchoring grooves 17 (FIG. 1) for receiving
 respective conductor rails 5. In the nonlimiting example of the drawings,
 the conductor rails 5 have rectangular cross section. However, persons
 skilled in the art will understand that other cross sections are certainly
 within the scope of the present invention. In like manner, each sleeve
 member 1a is formed with substantially C-shaped anchoring grooves 6 which
 are in alignment with the anchoring grooves 17 of the plastic profiles 3
 for receiving the conductor rails 5 and safeguarding the conductor rails 5
 against a shift in transverse direction. The anchoring grooves 6 form part
 of pertaining screw-type connecting assemblies 10 by which the conductor
 rails 5 are securely placed in end-to-end disposition with the conductor
 rails 5a of the other contact line segment 2 to be coupled, as shown in
 FIG. 2 which illustrates the other contact line segment 2 only by way of
 the conductor rails 5. In the non-limiting example of the drawing, a total
 of seven connecting assemblies 10 are used; however, it will be
 appreciated by persons skilled in the art that the number of connecting
 assemblies may vary in accordance to the dimensions of the contact line
 arrangement and associated coupling sleeve, and thus the present invention
 should not be limited to the incorporation of seven connecting assemblies.
 As the thermal expansion coefficient of metal, in particular copper, is
 relatively low, the end-to-end disposition of the conductor rails 5, 5a
 does not pose any problems. In contrast thereto, the plastic profiles 3,
 which are typically made of PVC have a thermal expansion coefficient which
 is greater by the factor nine to twelve.
 All of the conductor rails 5, 5a exhibit inwardly directed contact surfaces
 7 along which collector shoes of the trolley slide to maintain contact,
 without interruption, with the conductor rails 5, 5a when the trolley
 travels through the contact line arrangement. Thus, the trolley is capable
 to conduct current at any location of the contact line arrangement to an
 intended consumer.
 Turning now in particular in FIG. 3, there is shown a front elevational
 view of the end face of the contact line segment of FIG. 2. Schematically
 illustrated are two wheels 12 of the trolley, which travel along running
 surfaces 13 formed inwardly on the plastic profiles 3 and bounding the
 opening 4 on opposite sides thereof. Formed at the ends of the plastic
 profiles 3 are slots 14 which extend in longitudinal direction in each
 running surface 13 (FIG. 4) and have a width which is smaller than a width
 of the wheels 12. The slots 14 can be filled at least partially, otherwise
 completely, by guide ribs or bars 15 which are formed on platforms 21 of
 the sleeve members 1a and have such a length that a free space is left
 between an end of the bars 15 and the opposite slot end 16 (FIG. 4). Thus,
 the bars 15 engage in the slots 14 from below for displacement in the
 longitudinal direction and extend flush with the top side of the running
 surfaces 13 so that the plastic profiles 3 can shift relative to the bars
 15 and the trolley can travel along the running surfaces 13, without
 interference by the bars 15. In this manner, even when the plastic
 profiles 3 change in length as a consequence of temperature fluctuations,
 the wheels 12 of the trolley travel smoothly through the coupling sleeve
 1.
 As shown in particular in FIG. 2b, the ends of the plastic profiles 3 are
 further provided laterally with an oblong hole 19 of predetermined length
 for engagement of a protrusion 20 extending inwardly from the coupling
 sleeve 1, thereby preventing an unintentional removal of the plastic
 profiles 3 from the coupling sleeve 1. This configuration also enables to
 design the coupling sleeve 1 of relatively short length. In the
 nonlimiting example of the drawing, the connecting assembly 10 serves also
 as an inner stop for the ends of the plastic profiles 3.
 Persons skilled in the art will understand that the connector according to
 the present invention can also be used for conductor rails in the form of
 a continuous band after positioning the plastic profiles 3, i.e. to
 utilize the band feeding technique.
 Before realizing a connection between two contact line segments 2, one
 sleeve member 1a is placed over the end of one contact line segment 2 and
 the other sleeve member 1a is placed over the end of the other coupling
 line segment 2, whereby the protrusions of the sleeve members 1a engage in
 the oblong holes in the contact line segments. A sufficient fixation of
 the coupling sleeve 1 is realized through attachment of the sleeve members
 1a at the connecting assemblies 10. When being pushed together, the sleeve
 members 1a are thus connected by way of a positive engagement, and secured
 by the complementary locking elements 11, 11a.
 While the invention has been illustrated and described as embodied in a
 connector for coupling two current contact line segments in end-to-end
 relationship, it is not intended to be limited to the details shown since
 various modifications and structural changes may be made without departing
 in any way from the spirit of the present invention.