586 



Popular Science Monthly 



At Last! An Automatic Motor- 

 Driven Tire Pump 



CREWED in- 



AIR IN EXCESS OF DIAL 

 SETTING ESCAPES HE 



VALVE SEAT ^ 



^GAS TRAP 



C5 to the com- 

 pression-cock of 

 an automobile- 

 motor, the novel 

 airpump for pneu- 

 matic tires shown 

 in the accompany- 

 ing drawing is dis- 

 tinguished by the 

 use of a differen- 

 tial piston and a 

 spring - operated 

 diaphragm in 

 which the tension 

 of the spring con- 

 trols the pressure 

 of the air pumped 

 into the tires by 

 means of an exter- 

 nal notched dial. 



The pumping of the air is effected 

 through the use of two cylinders, one large 

 and one small. The larger is open to the 

 gases of the engine, while the smaller is open 

 to the atmosphere at one end. 



The differential piston, working in the 

 two cylinders, is carried on a hollow piston- 

 rod. As the piston is moved in one direc- 

 tion by the suction of the engine, air is 

 sucked into the small cylinder through a 

 check-valve. 



On the compression or explo- 

 sion stroke of the engine, the 

 large piston is forced in the 

 opposite direction, and 

 the air is forced into 

 the small cylinder be- 

 cause the check-valve is 

 closed, then through the 

 hollow piston-rod to the 

 chamber controlled by the 

 diaphragm under spring 

 tension and thence to the 

 tire in a tube. 



Both large and small 

 cylinders are water cooled 

 from the engine system. 

 The use of the differential 

 piston on the hollow rod 

 permits the air to reach the 

 tire without becoming im- 

 pregnated with any oil from 

 the engine-cylinder. The 

 pump is operated through a 

 valve in the compression- 



AIR INGRESS 

 AND EGRESS 



_ WATER JACKET 



WATER ADMITTED 

 HERE 



GAS fNSINE CYLINDER 

 Diagram of the automatic motor-driven tire 

 pump. The tension of the spring controls the 

 pressure of the air by means of an external dial 



cock nipple, which valve can be turned on 

 or off from the driver's seat by means of rod 



connections. Air 

 pumped by the 

 device after the 

 pressure at which 

 the diaphragm 

 has been set js 

 reached, is passed 

 off into the at- 

 mosphere, as indi- 

 cated in the 

 accompanying il- 

 lustration. 



In this way all 

 the strenuous la- 

 bor accompany- 

 ing the pumping 

 up of the automo- 

 bile tire is done 

 away with. 



A 



the 



The pocket is attached to the 

 rear face of the garter and 

 extends down into the sock 



A New Safety Pocket- Book Is 

 Combined witli the Garter 



PICKPOCKET would have no chance 

 of getting possession of the contents of 

 pocket-book illustrated, without a 

 strenuous tussle with the wearer. The best 

 of it is that no thief would be likely to sus- 

 pect the 'existence of such a pocket. 



Made as part of the garter, it is fastened 

 under the front pad and made to extend 

 down into the sock, as shown. There is a 

 flap which fastens with a glove 

 button arrangement to the outer 

 part of the garter. The pressure 

 of the elastic band serves to 

 make the closing still more 

 secure. 

 The pocket-book is thus con- 

 cealed inside the sock and 

 is made to lie flat against 

 the leg so that there is no 

 discomfort. If through 



careless fastening or other 

 negligence, the clasp should 

 come open while the garter 

 is in use, the purse would 

 slip down into the sock and 

 would be immediately felt, 

 so that there would be no 

 possible chance for it to be 

 lost without the owner's 

 being aware of it. 



It is the invention of Ed- 

 ward V. Crouse, of Chi- 

 cago, 111. 



