Counting mechanism for a motor vehicle washing plant
FIELD OF THE INVENTION 
     The invention relates to a counting mechanism for a motor vehicle washing plant, comprising a vertically movable switching member which is operated by the vehicle wheels on one side of a vehicle and which extends transversely to the direction of movement of the vehicle in its one wheel track, a stroke counter which is connected to the switching member and a conveyor device which is used to move the vehicle through the washing plant, which conveyor device has several spaced apart conveyor rollers on an endless tension member and are moved near the track along the one wheel track and each engage one vehicle wheel. 
     BACKGROUND OF THE INVENTION 
     Such counting mechanisms are used to count the number of motor vehicles actually washed for the purpose of providing a correct accounting. In a known counting mechanism, the switching member is arranged as a whip which is pivotal transversely with respect to the direction of movement of the vehicle. When the whip is pressed down twice by the wheels on one side of the vehicle, the stroke counter is switched on for one counter unit. By blocking the whip one can, however, cause the stroking unit not to continue to count and, as a result, the number of vehicles registered by the stroking unit no longer corresponds with the number of actually washed vehicles. 
     The basic purpose of the invention is to provide a counting mechanism for a motor vehicle washing plant of the abovementioned type which no longer can be put out of operation in an unauthorized manner and which therewith permits a correct counting of the actually washed motor vehicles. 
     This is achieved according to the invention by a switching member being arranged in the path of movement of the conveyor rollers, by the elevational movability of the swithing member extending perpendicular with respect to the track being at least as great as the distance of the highest point of each conveyor roller from the track and by the switching member being able to be moved after each pressing down by one wheel by a loading device and/or the conveyor roller into a ready position above the conveyor roller. 
     Due to this arrangement, an unauthorized blocking of the counting mechanism is no longer possible. That is, if one vehicle wheel comes into contact with the switching member, then same is pressed down on the track. After the vehicle wheel has rolled over the switching member, it is again lifted off from the track by the loading device, for example by a spring or by a counterweight or also by the conveyor roller itself and is moved into its ready position above the conveyor roller. After a second pressing down on the switching member, the stroke counter indexes one counting unit. Since the switching member is arranged in the path of movement of the conveyor rollers, it cannot be blocked in its lower position. The conveyor roller would namely then contact the switching member and press it upwardly. The switching member is also not able to be blocked in its upper ready position, because it would then be destroyed during rolling over by the wheel of the vehicle. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention is discussed more in detail hereinafter in connection with one exemplary embodiment which is illustrated in the drawings, in which: 
     FIG. 1 is a side view of a counting mechanism in ready position for contact with the wheel of a vehicle; 
     FIG. 2 is a side view of the counting mechanism during rolling engagement by the wheel; 
     FIG. 3 is a side view of the counting mechanism after the wheel has rolled over the counting mechanism and same has returned into the ready position; 
     FIG. 4 is a top view of the counting mechanism in the position according to FIG. 1; and 
     FIG. 5 is a cross-sectional view taken along the line V--V of FIG. 4. 
    
    
     DETAILED DESCRIPTION 
     The wheel of a motor vehicle is identified with reference numeral 1 in the drawings, which wheel rolls along on a track 2 of a washing plant. The vehicle is moved in direction A. To move the vehicle, several conveyor rollers 4 are used which are connected to endless tension members 3 and are moved also in direction A by the tension members 3. The conveyor rollers 4 are arranged in direct vicinity of the track 2 and are moved along one wheel track. The rollers engage in a conventional manner the rearwardly facing surface of a wheel on the vehicle which is to be washed to move the vehicle in direction A through the washing plant. 
     According to the invention, a switching member 5 is arranged in the path of movement of the conveyor rollers 4. This switching member consists advantageously of a two-arm lever 5a which is pivotal about horizontal axis a--a (FIG. 4) which extends transversely with respect to the path of movement of the conveyor rollers 4. The shaft 5b on which the lever 5a is mounted extends offset and parallel to the free end position and is rotatably supported in a bearing block 6. The lever 5a has at its free end a contact part 5c which extends transversely of the track and in the path of movement of the conveyor rollers 4 and cooperates with the vehicle wheels 1 for purposes explained hereinafter. 
     The pivot axis a--a of the lever 5a is advantageously arranged above the path of movement B of the highest point of each conveyor roller. The lever 5a is spaced laterally of the path of movement of the vehicle wheels 1, however, in the path of movement of the conveyor rollers 4 on their supporting parts, as for example the support rollers 7. The rotatble shaft 5b is connected through a coupling 8 to the stroke counter 9. A tension spring 10 engages the coupling 8 as a load device. In place of a draw spring it would also be possible if necessary to utilize a counterweight. The switching member 5 is returned by the draw spring 10 into its ready position illustrated in FIGS. 1, 3 and 5 and is held in said ready position thereby. The vertical movability of the switching member 5, in particular of its contact part 5c extending perpendicularly with respect to the longitudinal axis of the track 2 must be at least as great as the spacing b (Figure 5) of the path of movement B (Figure 1) of the highest point of each conveyor roller 4 from the bottom of the track 2. 
     If in this arrangement the vehicle wheel 1 contacts the contact part 5c, then the contacted point on the wheel moves on a different course than the contact part 5c which pivots about the axis a--a. Due to the rolling-along movement of the wheel 1, its point of contact with the contact part 5c will shift on the periphery of the wheel. This would, however, not be easily possible because of the static friction between the vehicle wheel and the contact part 5c. In order to prevent a jamming or nonpermissible load from occurring on the counting mechanism, the pivot axis a--a of the lever 5a is supported advantageously on a carriage which is movable parallel to the path of movement of the conveyor rollers, namely the bearing block 6 is arranged on said carriage 11. The carriage 11 is returned by means of a draw or tension spring 12 in a direction opposite to the conveying direction A into its initial position which is illustrated in FIGS. 1 and 5. 
     FIG. 1 illustrates the counting mechanism in its ready position. The wheel 1 and thus also the vehicle is moved in direction A by the conveyor roller 4 which engages the wheel 1. The wheel 1 contacts the contact part 5c of the switching member 5 during progressing movement. The switching member 5 is now pivoted downwardly about the axis a--a by the wheel until its contact part 5c rests on the bottom of the track 2. During this downward pivoting movement, the switching member 5 together with the carriage 11 is taken along in direction A against the force of the spring 12. Because of this additional movable support of the switching member 5, any relative movement between the contact part 5c and the wheel is eliminated and therewith a nonpermissible load on the counting mechanism is avoided. The wheel 1 rolls now over the contact part 5c which is supported on the track 2. After the wheel has rolled thereover, the switching member is swung upwardly again into its ready position by means of the spring 10 wherein the contact part 5c is above the path of movement B of the highest point of the conveyor rollers 4. After a second pressing down of the switching member 5 by the two wheels on one side of the vehicle, the stroke counter 9 will be indexed and register one counting unit. 
     The switching member 5 cannot be blocked in any position. Namely, if one would block it in the lower position, then the conveyor roller 4 would contact the contact part 5c and then either the contact part 5c would be damaged or the conveyor device would be switched off by a safety device. Also a blocking of the switching member in its upper ready position is not possible, because the switching member 5 would then be excessively loaded by the vehicle wheel and would be damaged. In the particularly advantageous embodiment which is illustrated in FIGS. 1 to 5, damage to the switching member 5 is substantially eliminated by the lever 5a extending into the path of movement of the support rollers 7. During the progressing movement of the support rollers 7, same come into contact with the lever 5a and pivot same upwardly into its ready position. This is also important in case the spring 10 should break. 
     Although a particular preferred embodiment of the invention has been disclosed in detail for illustrative purposes, it will be recognized that variations or modifications of the disclosed apparatus, including the rearrangement of parts, lie within the scope of the present invention.