United States Patent (11) 3,589,205 72) inventor Zeljko Radovic 56) References Cited f 5. Switzerland UNITED STATES PATENTS i. App. No 1969 349,624 911886 Abt ...... 05/29 X i: Pated R396, 991,954 5, 1911 Charbonneau...... 105/29 73) Assignee Sybron Corporation 3,429,280 2/1969 Dashem et al...... - - - 105/29 g R ty 3,443,449 5/1969 Kotarski...... 74.1422 (32) Priority July 11, 1968 FOREIGN PATENTS (33 Germany 57,432 6f 19 l l Switzerland...... 105/29 31 P 7 5S 926. Primary Examiner-Arthur L. La Point Assistant Examiner-Howard Beltran Attorney-Theodore B. Roessel

54 RACK AND PINIONSYNCHRONIZING ABSTRACT: A E. mechanism to effect smooth in MECHANISM terference free transition from friction to positive drive is ac 6 Claims, 2 Drawing Figs. gearcomplished 22 is carried by a gear into 22 engagement mounted on with a drive an axiallyshaft 10,movable which 52 U.S. Cl...... 74/422, rack 24 to move the rack axially with respect to the positive 74/411, 105,129, 105/30, 105.1127, 1051131,295/4 drive track portion 20 against the force of a-spring 26 until the (51 Int. Cl...... B61c11/04, gear and rack are meshed. The rack is then moved by the F16h 1104, F16h 57/00 meshed gear against a stop 28 which orients the positive drive (50 Field of Search...... 74/422, means 6 for smooth friction free engagement with the posi 411; 105/29, 30, 127, 131; 295/4 tive drive portion 20.

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At TORNEY 3,589,205 2 A further object of the invention is to provide means for RACK AND PINIONSYNCHRONIZING MECHANISM making the transition from friction to positive drive without stopping the forward motion of the transport vehicle. Yet another object of this invention is to provide means for Background of the Invention orienting a moving positive drive member with respect to a The present invention relates to a rail-guided vehicle having stationery positive drive member to permit said members to a friction drive means and a positive drive engageable with the mesh smoothly and without interference. rail wherein the positive drive is engaged for only a portion of These and other objects, advantages and characterizing fea the travel of the vehicle. More specifically, the present inven tures of the invention will become more apparent upon con tion relates to a device for effecting the smooth transition O sideration of the following detailed description thereof when from friction to positive drive while the vehicle is in motion. taken in connection with the accompanying drawings. Rail-guided vehicles, such as monorails which permit a pro grammed transportation of material to unloading and loading Description of the Drawings stations are already in use in factories, offices, hospitals and 5 FIG. 1 is a plan view of the gear orienting means of the the like. These transport vehicles usually have a on present invention; and which is mounted one or more which frictionally en FIG. 2 is a front view of the apparatus shown in FIG. 1. gage the monorail track. In cases where the track extends through a horizontal path of travel, the weight of the transport Description of the Preferred Embodiment vehicle usually exerts a sufficient load on the friction drive 20 Referring to the drawings the transport vehicle according to wheels so that the vehicles can move along the track without the friction drive wheels slipping. However, in cases where the the invention has two drive shafts indicated at 10. Mounted on track extends vertically, the force exerted by the friction drive each drive shaft is a friction drive 12 consisting of two wheels against the track is insufficient to overcome the weight portions 12a and 12b (FIGURE 2). These friction drive of the transport vehicle so that the friction drive wheels alone 25 wheels are adapted to frictionally engage a track 14 to drive are unable to move the transport vehicle vertically. Therefore, the transport vehicle along horizontal courses of travel. an additional drive means such as a positive drive is necessary Also mounted on drive shaft 10 and between the friction to move the transport vehicle along vertical sections of the drive portions 12a and 12b is an apertured positive drive track. Such a positive drive can take the form of a chain and wheel 16 (FIG. 2). The apertures 18 of wheel 16 are equally sprocket or a tooth system or the like, such as a rack or similar 30 spaced and extend radially inward from the periphery of the device on the vertical section of track and a drive pinion on wheel so as to engage a series of equally spaced bolts or pins the transport vehicle. 20 provided on each side of track 14. These bolts or pins 20 The problem with such dual drive vehicles is in making the comprise the positive drive rack section of the trackway as for transition from friction to positive drive smoothly and without example, during vertical courses of travel. stopping the transport vehicle. The greatest difficulty is in en 35 The synchronizing mechanism has mounted gaging the positive drive means on the vehicle with the posi on each drive shaft 10 a pinion gear 22a and 22b which is tive drive portion of the track smoothly and with a minimum adapted to orient positive drive wheels 16 for smooth, inter of shock and noise. Any interference with the rotating positive ference free engagement with bolts 20 in a manner set out drive and the positive drive portion of the track will, of course, herein below. Gears 22a and 22b are smaller in diameter than increase the risk of damage to components of the drive means 40 friction drive wheels 12 and are adapted to mesh with a travel or at the very least may present the danger of spilling the ing rack 24a and 24b respectively, located immediately in material being transported. In the case of offices and hospitals, front of the positive drive rack section of the track another disadvantage is the noise created by any interference represented by bolts 20. Each traveling rack is longitudinally between the drive means and the positive drive portion of the moveable with respect to the rail and is fastened at one end to track. 45 the rail by a spring element shown schematically in FIGURE 1 by the single spring element 26, the traveling rack sections SUMMARY OF THE INVENTION being moveable independently of each other in a direction of In the present invention, a rail-guided vehicle is driven motion toward or away from a stationery stop 28 provided on horizontally by a which frictionally engages the 50 track 14. The first tooth 30a and 30 b of each rack 24a and horizontal section of monorail track. For vertical courses of 24b respectively, is pivoted to the traveling rack and biased by travel, the vehicle is provided with a positive drive wheel a spring 32 to move in the plane of the rack. which engages a positive drive section of the track. Im It should be pointed out that while the diameter of gears 22a mediately preceeding the positive drive section of track is an and 22b is smaller than the diameter of positive drive wheel 55 16, the relationship of the gears, positive drive wheels 16, axially movable, spring-biased rack, adapted to mesh with a racks 24a and 24b and bolts 20 is such that when the gears and gear mounted for corotation with both the friction drive wheel the traveling racks are meshed and the racks abutted against and the positive drive wheel. Misalignment of the gear and stop 28, the apertures 18 of positive drive wheel 16 will be in rack causes the rack to move laterally with respect to the rail correctorientation to mesh smoothly with bolts 20. until meshing occurs. Thereafter, the rack is driven toward the 60 In order to describe the operation of the present invention positive drive section of the track and into engagement with a and by way of illustration only, assume that the transport vehi stop, the gear and positive drive wheel being oriented so that cle is in friction drive with drive wheels 12 rotating so as to meshing of the gear and rack and abutment of the rack against move the transport vehicle from left to right as viewed in FIG. the stop places the positive drive wheel in the correctorienta 1 and toward the positive drive rack portion of the track tion to mesh smoothly with a positive drive section of the track 65 represented by bolts 20. If, for example, gear 22a first engages OBJECTS OF THE INVENTION the right flank of the first tooth 30a of rack 24a, the rotation of the gear will cause the traveling rack to move to the left until It is the primary object of the invention to provide a trans the gear and rack are in proper meshing engagement. How porter vehicle for a monorail system having both a friction and ever, if for example, gear 22b engages the crown of the first a positive drive means in which the transition from friction to 70 tooth 30b of rack 22b, the tooth will be depressed against the positive drive is made with a minimum of shock and noise. bias of spring 32 thereby increasing the pitch from the first Another object of the present invention is to provide means tooth 30b to the following tooth 34 of the rack. The next tooth for making a transition from friction drive to positive drive of gear 22b will now engage on the left flank of tooth 34 as which reduces the wear of the friction drive resulting from shown in FIGURE 1 and will move rack 24b to the right until slippage during engagement of the positive drive means. 75 the gear and rack are in proper meshing engagement. 3,589,205 3 4. As stated herein above the diameter of drive wheels 12 is vehicle drive pinion for smooth friction free engagement greater than the diameter of gears 22a and 22b so that with the with said positive drive rack section. gears correctly meshed with their respective racks, the friction 2 A combination as set forth in claim 1 wherein said orient drive wheels will cause both the gears and the traveling racks ing means comprises a pinion gear mounted on said vehicle to move to the right as viewed in FIG. 1 until the racks engage 5 drive shaft, said gear being adapted to mesh with said traveling stop 28. With the racks abutting against stop 28 apertures 18 rack and being smaller in diameter than said friction drive of positive drive wheel 6 are in the correct orientation to eaS. mesh smoothly with bolts 20 as shown in phantom in FIG. 1. 3. A combination as set forth in claim 2 wherein the first As positive drive wheels 16 move along the positive drive tooth of said traveling rack disposed for engagement with said section of the rail, gears 22a and 22b run off from racks 24a O pinion gear is resiliently mounted on said traveling rack. and b respectively so that the racks can be drawn by spring 26 4. Rack and pinion synchronizing means to engage a rack back to their original position. and pinion drive for use with guided vehicles having a drive Thus, it would be appreciated that the present invention ac shaft, a friction drive wheel and a positive drive pinion, said complishes it intended objects by providing a means for effect means comprising: ing the smooth transition from friction to positive drive with a 15 a, a rail having both a friction drive portion and a positive minimum of shock and noise. Racks 24a and b being drive rack section, said positive drive rack section being resiliently mounted provide the means to absorb much of the engageable with said positive drive pinion on said vehicle shock prior to the engagement of drive wheels 16 with bolts for only a portion of travel of said vehicle; 20. Shock and noise is further minimized by having the first b. a traveling rack mounted on said rail preceding said posi tooth of each rack resiliently mounted. 20 tive drive rack section, said rack being movable through a Having thus described the invention in detail, what I claim path of travel longitudinally with respect to said rail; as new is: c. bias means urging said traveling rack to an intermediate 1. Rack and pinion synchronizing means to engage a rack point in said path of travel; and pinion drive for use with rail guided vehicles having a d. a stop on said rail to limit movement of said traveling rack drive shaft and a drive pinion, said means comprising: 25 in the direction toward said positive rack section; and a. a rail having both a friction drive portion and a positive e. a gear mounted on said drive shaft adapted to mesh with drive rack section, said positive drive rack section being Said traveling rack, said gear engaging and moving said engageable with said drive pinion on said vehicle for only traveling rack longitudinally with respect to said rail until a portion of travel of said vehicle; said gear and traveling rack are meshed and thereafter b. a traveling rack mounted on said rail preceding said posi 30 moving said traveling rack against said bias and toward tive drive rack section, said traveling rack being movable said stop, said gear, traveling rack, stop and said vehicle through a path of travel longitudinally with respect to said positive drive pinion and said rail positive drive rack sec rail; tion being so oriented that meshing of said gear and c. resilient means normally maintaining said traveling rack traveling rack and location of said traveling rack against at an intermediate point in the path of travel of said 35 said stop will cause said vehicle positive drive pinion and traveling rack; said rail positive drive rack section to mesh smoothly. d. orienting means on said vehicle adapted to engage and 5. A combination as set forth in claim 4 wherein the first drive said traveling rack through said path of travel and tooth of said traveling rack in the direction of movement of toward said positive drive rack section; and said vehicle is pivotally mounted on said traveling rack and e. a stop disposed in the path of travel of said traveling rack 40 spring biased to resist movement upon engagement by said for limiting the movement thereof towards said positive gear on said vehicle drive shaft. drive rack section, said stop being located so that engage 6. A combination as set forth in claim 4 wherein said gear is ment of said traveling rack and orienting means and abut smaller in diameter than said friction drive means. ment of said traveling rack against said stop locates said 45

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