US2206621A

US2206621A - Pneumatic tire tube

Info

Publication number: US2206621A
Application number: US200773A
Authority: US
Inventors: Smith Edgar Alton
Original assignee: Individual
Current assignee: Individual
Priority date: 1938-04-07
Filing date: 1938-04-07
Publication date: 1940-07-02
Anticipated expiration: 1957-07-02

Description

H n M S E PNEUMATIC TIRE TUBE Filed April 7, 1938 2 Sheets-Sheet l In venior A itqrneys July 2, 1940; E, A, SMITH PNEUMATIC TIRE TUBE Filed April 7, 1938 2 Sheets-Sheet 2 Inventor j z w 7 m a nk z gmmy E 1, Q /J M, 7 f M 3 w a f; m ww Attorneys Patented July 2, 1940 UNITED STATES PATENT orrics PNEUMATIC TIRE TUBE Edgar Alton Smith, New York, N. Y. Application April 7, 1938, Serial No. 200,773

3 Claims.

The present invention relates to new and useful improvements in tubes for pneumatic tires and has for its primary object to provide, in a manner as hereinafter set forth, a tube having incorporated therein a pump of a novel construction and arrangement for automatically maintaining the air in said tube at a predetermined pressure.

Other objects of the invention are to provide an automatically inflated inner tube of the aforementioned character which will be comparatively simple in construction, strong, durable, highly efficient and reliable in use, compact and which may be manufactured at low cost.

All of the foregoing and still further objects and advantages of the invention will become apparent from a study of the following specification, taken in connection with the accompanying drawings wherein like characters of reference designate corresponding parts throughout the several views, and wherein:

Figure 1 is a view in vertical section through a portion of an inner tube embodying the present invention, the base portion of the pump being shown in section with the rest of said pump in side elevation.

Figure 2 is a view in end elevation of the pump.

Figure 3 is a vertical sectional vi the pump.

Figure 4 is a view in horizontal section, taken substantially on the line 4-4 of Fig. 3.

I Referring now to the drawings in detail, it will be seen that the reference numeral l designates an inflatable inner tube mounted in a conventional casing 2. Formed integrally with the inner periphery of the tube I is a rubber base 3 having an air passage l therein. The base 3 includes a tubulare stem 5 which is adapted to project through the rim 6 on which the tire is mounted Mounted on the base 3 is a cylinder l of suitable material. The inner end of the cylinder 7 is closed, as at 8, and projecting therefrom is a neck 9 which is secured to an extension it on the base 3 for mounting said cylinder on said base. A pin H anchors the neck 9 to the extension Ill. The cylinder 1 is open at its outer end.

The reference numeral l2 designates a comparatively small outer cylinder which is adapted to be moved into the inner cylinder 7. The cylinder 5? is closed at its outer end, as at l3. The inner end of the cylinder I2 is closed by a piston M which is fixed thereon and which is slidably engaged in the cylinder I. The piston I l com- 55 prises a cup l5 engaged with the walls of the gw through cylinder 1 in the usual manner. The piston i l further includes a disk 26 in the cup I 5, said disk being secured to the cylinder [2. The piston it still further includes a check valve it through which air is forced from the inner portion of the cylinder I2 into the cylinder 1 by the piston l9. Any desired number of the check valves it may be provided in the piston M.

Also mounted in the extension ill on the base 3 and communicating with the air passage l is a tube or conduit ii. The pin ll passes through the conduit H for anchoring same in the extension ill of the base 3. The air conduit ll constitutes an inlet pipe which extends through the cylinder 7 and the piston It into the cylinder ill. The piston 14 is slidable on the inlet pipe ii. A check valve 88 is provided in the inlet pipe ll to prevent the escape of the airfrom the outer portion of the cylinder l 2 back through said inlet pipe ll. Mounted on the inlet pipe I? and up:- erable in the cylinder i2 is a piston l9 comprising a cup 20. The piston it further includes a disk 21 in the cup 20.

Fixed on the closed end it of the cylinder i2 is a. nose 2! which is engageable with the outer periphery of the tube 2 in the manner shown to advantage in Fig. 1 of the drawings. The base of the nose 2| comprises a flange 22 which projects beyond the periphery of the closed end it of the cylinder l2. A cupped flange 23 projects from the closed end 8 of the cylinder 1. The reference numeral 24 designates a coil spring which encircles the cylinders "i and i2 and which has its ends engagedwith the flanges 22 and 2t.

Briefly, the operation of the device is substantially as follows:

The tire is first inflated to the desired pressure in the usual manner. This pressure is such that, acting on the piston It, the cylinder i2 will be moved into the cylinder 7 against the tension of the coil spring 24, thus moving the nose 2i out of contact with the tube l. With the cylinder l2 and the nose 2| in this position, the pump will not function as the tire rolls over the highway. However, should the pressure in the tire drop to any considerable extent, the spring 2% will move the cylinder outwardly and contact the nose 2! with said tire. Then, when the tire flexes under the load as it contacts the highway the. cylinder It with the piston Hi thereon will be forced into the cylinder 1 against the tension of the coil spring 24, the piston i9, of course, remaining stationary. Thus, air trapped in the cylinder 7 is forced past the cup l5 into the tube l and air trapped into the cylinder I2 is forced past the cup 20 into the chamber between said piston l4 and the piston l9. When the portion of the tire with which the nose ZI is engaged leaves the highway the cylinder 12 is forced outwardly by the spring 24. When this occurs, air from the atmosphere is drawn through the inlet pipe ll into the cylinder l2 and the air thus trapped between the pistons I4 and IS in the cylinder I2 is forced past the check valve I6 into the cylinder I. This operation is repeated until the pressure in the tire has again been built up to the desired point when the piston M will again be forced inwardly and held in this position, thus again moving the nose 21 out of contact with the tire;

It is believed that the many advantages of an automatic tube inflating means constructed in accordance with the present invention will be readily understood and although a preferred embodiment of the device is as illustrated and described, it is to be understood that changes in the details of construction and in the combination and arrangement of parts may be resorted to which will fall within the scope of the invention as claimed.

What is claimed is:

1. A pneumatic tire including an inflatable tube, a cylinder mounted in said tube on the inner periphery thereof, a piston operable in said cylinder, a comparatively small cylinder mounted on the piston and projecting outwardly therefrom, an air inlet pipe communicating with the atmosphere and extending through the first named cylinder into the second named cylinder, the piston being slidable on said inlet pipe, a piston fixed on the inlet pipe and operable in the second named cylinder, a check valve in the inlet pipe for preventing the return flow of air to the atmosphere, the first named piston having a check valve controlled passage therein for admitting air to the first named cylinder from the second named cylinder, and a spring engaged with the second named cylinder for yieldingly urging same outwardly for engagement with the outer periphery of the tube for actuation thereby.

2. A pneumatic tire including an inflatable tube, a resilient base integral with the inner periphery of the tube, said base having an air passage therein communicating with the atmosphere, a cylinder mounted on the base in the tube, an air inlet pipe mounted in the air passage in the base and extending longitudinally into the cylinder, a check valve in the inlet pipe, a piston fixed on said inlet pipe, a piston operable in the cylinder and slidably mounted on the inlet pipe, a comparatively small cylinder fixed on the second named piston and slidable on the first named piston, said second named piston having a check valve controlled opening therein for the passage of air from the second named cylinder into the first named cylinder, the first and second named pistons including cups engaged with the walls of the cylinders, and means for operatively connecting the second named cylinder to the outer periphery of the tube for actuation thereby when said tube is flexed.

3. A pneumatic tire including an inflatable tube, a resilient base integral with the inner periphery of the tube, said base having an air passage therein communicating with the atmosphere, a cylinder mounted on the base in the tube, an air inlet pipe mounted in the air passage in the base and extending longitudinally into the cylinder, a check valve in the inlet pipe, a piston fixed on said inlet pipe, a piston operable in the cylinder and slidably mounted on the inlet pipe, a comparatively small cylinder fixed on the second named piston and slidable on the first named piston, said second named piston having a check valve controlled opening therein for the passage of air from the second named cylinder into the first named cylinder, the first and second named pistons including cups engaged with the walls of the cylinders, and means for operatively connecting the second named cylinder to the outer periphery of the tube for actuation thereby when said tube is flexed, said means including a nose member fixed on one end of the second named cylinder, a flange projecting from the base portion of said nose member, a flange projecting from the first named cylinder, and a coil spring encircling the cylinders and having its ends engaged with the flanges.

EDGAR ALTON SMITH.