Railway track mounting arrangement
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention in general relates to an apparatus for mounting a monitor to a rail of a railway track and, more particularly, to an apparatus which permits periodic adjustments in the position of the monitor relative to the rail head of a rail. 
     2. Description of the Prior Art 
     Such arrangements are well-known in the art and serve to position monitoring devices such as transducers or railway switches, and the like in as precise a position relative to the rail head of a rail as possible to ensure proper and flawless operation of the monitor. The rails, under the impact of traffic, are subject to considerable wear and tear resulting in a gradual lowering or disfiguring of the running surface of the rail head and, accordingly, periodic adjustments in the position of the monitor relative to the rail head is indicated. The monitors, as is well-known, serve to release signals in response to approaching wheels, and the signals are in turn utilized to actuate ancillary equipment such as warning lights or road crossing barriers and the like. 
     One arrangement of the kind under consideration is disclosed by European patent specification 0 342 526. Vertical movement of a monitor in accordance with that arrangement is accomplished by two vertically disposed adjustment bolts by means of which a mounting bracket may be moved relative to another mounting bracket. The adjustment bolts are provided with axial bores in which threaded bolts are seated for connecting the monitor to the brackets. In order to adjust the position of the monitor relative to the level of a rail head it is, therefore, necessary first to release bolts which maintain the relative position of the two brackets, thereafter to loosen the mounting bolts, and then to rotate the adjustment bolts for repositioning the monitor. Subsequent to the repositioning of the monitor the mounting bolts and the clamping bolts have to be tightened again. 
     Another arrangement is known from U.S. Pat. No. 4,753,403. The arrangement utilizes a lockable arrangement attached to the base of a rail for supporting a mounting bracket for a monitor. Each of two clamps is provided with a lug which serves to support the mounting bracket by means of a bolt threadedly received in the lug and extending through a vertical elongate slot in the bracket. Heightwise adjustment of the monitor requires loosening of the bolt in each lug and depends in no small measure upon the skill of the person attempting the heightwise adjustment by manually raising or lowering the monitor and maintaining its new position until the mounting bolts are again tightened. 
     Arrangements of the kind described in the prior art are disadvantageous in that they are either unduly complicated in their construction and utilization. Moreover, they may be subject to jamming during their heightwise repositioning. 
     It is, therefore, an object of the present invention to provide a mounting arrangement for a rail monitor which while structurally simple facilitates precise periodic adjustments in the position of the monitor relative to a rail. 
     It is a further object of the invention to provide a mounting arrangement for a monitor of the kind under consideration which includes a vertically disposed slide arrangement for accurately guiding the monitor during vertical movements necessary for its positional readjustments. 
     Yet another object of the invention resides in the provision of a positive vertical guide in the mounting arrangement of a monitor to prevent tilting or canting in directions parallel to the rail and possible jamming. 
     SUMMARY OF THE INVENTION 
     In the accomplishment of these and other objects the invention provides, in an apparatus for adjusting the position of a monitoring device relative to the rail head of the rail, a bracket adapted to be affixed to the rail and having a substantially vertically disposed surface and another bracket for supporting the monitoring device for selective vertical movement in engagement with the surface. The surfaces are respectively provided with a vertically disposed recess and protrusion of complementary cross-section or configuration. The brackets are releasably connected to each other with the surfaces in mating engagement. The surfaces serve as slides by means of which the brackets may be moved relative to each other in a substantially straight path by means of a drive spindle arrangement. 
     Other objects of the invention will in part be obvious and will in part appear hereinafter. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will now be described in connection with preferred embodiments, with reference to the accompanying drawings, in which: 
     FIG. 1 is an elevational view of a first embodiment of the invention; 
     FIG. 2 is an elevational view of a second embodiment of the invention; 
     FIG. 3 is a cross-sectional view, on an enlarged scale, of a first configuration of mating surfaces between rail and monitor mounting brackets; 
     FIG. 3a is a view similar to FIG. 3, depicting an alternate surface configuration; 
     FIG. 3b is a view similar to FIG. 3, depicting a different mating surface configuration; 
     FIG. 3c is a view similar to FIG. 3, showing yet another mating surface configuration; 
     FIG. 4 is a front elevational view, partially in section, depicting details of one of the mounting brackets. 
    
    
     DESCRIPTION OF THE INVENTION 
     A first embodiment of an apparatus 3 in accordance with the invention is depicted in FIG. 1. A support bracket 7 is rigidly connected, in a substantially horizontal orientation, to a rail 21 intermediate the head 1 and base 22 thereof by means of one or more bolts 4 (only one shown). A wheel 2 is schematically indicated as being positioned on the rolling surface of the rail head 1. The free end of the bracket 7 is provided with a guide surface 5 to be described in detail hereinafter. A carriage 6 serving to support the housing 26 of a monitor is seen to be attached to the guide surface 5 by bolts 13, in a predetermined elevational position relative to the wheel 2 or rail head 1. As will be appreciated by those skilled in the art, it is this relative position which is of utmost importance to the flawless operation of the monitor. 
     FIG. 2 in which similar elements are identified by similar but primed reference characters depicts an alternate embodiment of the invention. In this embodiment the mounting bracket consists of a clamping arrangement including first and second clamp portions 8 and 9 provided with lugs 18 engaging opposite marginal portions of the base 22&#39; of a rail 21&#39;. The clamp portion 8 is seated on a threaded spindle 10 extending from the clamp portion 9, and a nut 23 seated on the spindle 10 is provided to secure the engagement of the clamp portions 8 and 9 with the base 22 of the rail. A lock washer 23a may be seated between the nut 23 and an abutting surface of the clamp portion 8 to prevent unintentional loosening of the nut 23. The clamp portion 9 is provided with a guide surface 5&#39;. A slide 6&#39; is seen to be held in clamping engagement against the guide surface 5&#39; by means of one or more bolts 13&#39;. As in the embodiment described supra, the slide 6&#39; permits adjustments in the elevational position of the housing 26&#39; of a monitor relative to the rail head 1&#39; or wheel 2&#39;. 
     FIG. 3 is a cross-sectional view of a first configuration of a guide surface 5 and the abutting surface of the slide 6. The guide surface 5 is seen to consist of three parallel sections 20, 20a and 20b, sections 20 and 20b being positioned at acute angles relative to the section 20a in a direction toward the slide 6. The carriage or slide 6 is seen to be provided with a surface consisting of three parallel and vertically aligned sections 24, 24a, and 24b which complement the surface sections 20, 20a, and 20b and in the manner of this invention may selectively slide in engagement therewith. The surface sections 20, 20a, and 20b of the guide surface 5 may be said to constitute a groove, whereas the surface sections 24, 24a, and 24b function in the manner of a rail and constitute an elongated protrusion designed to mate with the groove. The groove and protrusion are respectively of female and male trapezoidal cross-sectional configuration. 
     The embodiment shown in FIG. 3a differs from that of FIG. 3 in that its arrangement is the reverse of the arrangement of FIG. 3, i.e., the guide surface 5&#39; is configured as an elongate protrusion or rail comprising parallel portions 20&#39;, 20a&#39;, and 20b&#39;, whereas the slide 6&#39; is provided with a mating groove made up of surfaces 24&#39;, 24a&#39;, and 24b&#39;. 
     In FIG. 3b the mating surfaces of the guide surface 5&#39;&#39; and of the slide 6,, are seen to be joined in a dovetail arrangement, the mortises being provided in the guide surface 5&#39;&#39;, the tenons being provided in the slide 6&#39;&#39;. 
     The arrangement of FIG. 3c also shows a dovetail joint between guide surface 5&#39;&#39;&#39; and slide 6&#39;&#39;&#39;. In this case, however, the tenons are in the guide surface 5&#39;&#39;&#39; and the mortises are provided in the slide 6&#39;&#39;&#39;. 
     The mating surfaces of the various exemplary embodiments shown are such that they may provide relative sliding movement, means to be described being provided, however, to prevent such movement in normal circumstances While the depicted embodiments all comprise trapezoidal interfacial relationships, other configurations such as semicircular, triangular or rectangular groove and rail arrangements are further examples of mating surface within the scope of the invention. 
     Aside from showing different possible mating surface arrangements between guide surface 5 and slide 6, FIGS. 3, 3a, 3b, and 3c also depict a threaded spindle 11 seated in a threaded bore of a tab 12 protruding from the lateral center, i.e., section 20a of the guide surface 5. Rotating the spindle 11 results in controlled continuous movement of the slide 6 along the guide surface 5 in the manner to be described infra. 
     As best seen in FIG. 4, there are provided in the slide 6 laterally displaced from and extending parallel to the spindle 11 on opposite sides thereof, elongate slots 17. Threaded bolts 13 are seated in the slots 17 and are received in threaded bores 14 sunk into the guide surface 5 and may serve selectively to secure the slide 6 against movement relative to the bracket 7 or clamp portion 9 for retaining the housing 26 of the monitor in the most favourable or efficacious position relative to the rail head 1. 
     Intermediate the slots 17 the slide 6 is also provided with coaxially arranged recesses 27 and 28 interconnected by a threaded spindle 11. The spindle 11 extends through the bore 28a from the recess 27 to the recess 28. The recess 27 is provided with axially displaced shoulders 27a and 27b and is of a width sufficient to accommodate a collar 15 affixed to the spindle 11. The collar 15 is secured against rotation relative to the spindle 11 by means of a clamp nut 25. Within the periphery of the collar 15 there is provided a plurality of radial bores 16, the purpose of which is to accommodate a tool for rotating the spindle 11. As seen in FIG. 4, the tab 12 extends from the guide surface 5 into the recess 28. The axial dimension of the tab being considerably less than that of the recess 28 to provide the space necessary for the desired elevational change in position of the slide or carriage 6, the direction of rotation of the spindle 11 determining the direction of movement of the slide 6. The axial surfaces of the collar 15 are in slidable engagement with the shoulders 27a and 27b of the recess 27. The slots 17 are, of course, of a longitudinal dimension substantially equal to, but not less than the length of the recess 28. As shown, the clamping bolts 13 and the tab 12 are located about in the longitudinal center of the slots 17 and recess 28, respectively, to allow movement of the slide relatively to the guide surface 5 in either direction. 
     Threaded bores 19 provided in the slide 6 and extending substantially parallel to the slots 17 are provided to receive bolts for mounting the housing 26 of the sensor on the slide. 
     As will be appreciated by persons skilled in the art the arresting and motion imparting arrangements described in connection with the embodiment of FIG. 3 are similarly applicable to the embodiments of FIGS. 3a, 3b, and 3c to that detailed descriptions in connection therewith are thought to be unnecessary. 
     Although the embodiments of the invention depicted and described hereinabove constitute preferred forms thereof, modifications may be made without leaving the ambit and scope of protection of the invention as set forth in the claims.