98 



CAKRIERS, MECHANICAL. 



and D is a lever connected with the switch. 

 can be shifted to register with D wherever 

 placed, and thus a large number of carriers 

 can run upon a single track, each turning off 

 at its proper station, leaving the track clear. 

 A similar arrangement, with the adjustment 

 bars straight instead of curved, may be em- 

 ployed though the number of possible switches 

 is considerably reduced in that case, owing to 

 the limitations of space, and the unavoidable 

 oscillations of a single- track car. With a dou- 

 ble track, as in a cable system (Fig. 11), a 

 nicer adjustment is practicable. The ends of 

 the carriers in a single-track system are shaped 

 with reference to possible collisions and are 

 provided with buffers so that only a momentary 

 delay results from a chance encounter. The 

 carrying capacity varies, of course, with the 

 strength of construction, but the ordinary re- 

 tail business, where many customers carry away 

 their purchases, seldom calls for a capacity of 

 more than twelve or fifteen pounds. 



The carrier-systems thus far described have 

 depended for motive power mainly upon the 

 always available force of gravity, but gravity 

 is too slow for modern ideas and other means 

 have been adopted. First among these, be- 

 cause simplest, is the "Spring Carrier." It 

 consists of a single taut wire beneath which a 

 small cash-carrier is suspended arranged so as to 

 be readily opened from below without detach- 



FlG-.IO 



SWITCHING DEVICE. 



ing the car from the wire. The wire stretches 

 from a salesman's station to the cashier's desk, 

 and at each end is a spring either of rubber or 

 wire operated by a handle and a releasing- 

 clutch. The carrier can be sent almost instan- 

 taneously from end to end of the wire up to a 

 distance of 150 feet. The longest line in oper- 

 ation in New York is 180 feet. This system 

 commends itself for inexpensiveness and sim- 

 plicity, and is especially adapted for use in 

 shops of moderate size. 



One of the most elaborate of the modern 

 cash-carriers is precisely similar in general con- 

 struction to cable railways as described in the 

 "Annual Cyclopasdia" for 1886. The minor 



details involving automatically-acting switches 

 are different and merit a description. 



The cable is simply an endless wire running 

 over drums at the ends, and bearing upon 

 sheaves wherever necessary in passing curves 

 or the like. The cable runs between light rails 



A CABLE-CAIUUER. 



upon which the carriers slide, and a guide-rod 

 provides against accidental derailment in tran- 

 sit. In Fig. 11 the arrows show the direction 

 of motion in the cable. A is the carrier, and 

 B a lever acting upon the cable-grip C. The 

 salesman has several of the carriers within 

 reach, and when he wishes to send one to the 

 cashier he raises the lever B, and sets the car- 

 rier upon the rails in a position it necessarily 

 assumes. Placing his finger upon the lever B, 

 he presses it downward; the grip C closes 

 upon the moving cable, and the carrier disap- 

 pears so swiftly that the eye can hardly follow, 

 perhaps plunging down through an opening in 

 the floor to the cashier's department, whence it 

 is returned at a like rate of speed, and switches 

 itself off upon a little platform at the proper 

 station. The switching device is unlike any of 

 those described, in that a thin curved piece of 

 metal is fixed at each station in such a position 

 that it engages projections set on top of the car- 

 rier and derails it at the proper point. First, 

 however, the cable-grip is automatically re- 

 leased by an inclined fixture against which the 

 lever B strikes just before reaching the switch. 

 At the switch there is a break in the guide-rod 

 D, so that the carrier is free to leave the rails 

 and falls into a suitable receptacle. The whole 

 structure of rails, guide-rods, and supports oc- 

 cupies very little space, and can be so disposed 

 as not to be in the least unsightly or incon- 

 venient. The motive power can be derived 

 from any available source steam, electricity, 

 water, or the like. 



It remains to notice the pneumatic systems 

 which are operated through tubes of glass or 

 metal, either by exhaust-engines or by means 

 of compressed air. These systems necessitate 

 a special tube for each salesman's station, all 

 converging at the cashier's desk. The tubes 

 are about two inches in diameter, and the car- 

 riers are cylindrical, fitting the tube loosely, 



