US1415283A - Inner tube for automobile tires - Google Patents

Description

H. N. WAYNE. INNER TUBE FOR AUTOMOBILE TIRES. APPLICATION FILED AUG.2I, 1920. RENEWED SEPT. 28. 1921.

Patented May 9, 1922.

. longitudinal as STATES PATENT INNER TUBE FOR AUTOMOBILE TIRES.

Specification of Letters Patent.

Patented May 9, 1922.

Application filed August 21, 1920, Serial No. 405,005. Renewed September 28, 1921. Serial No. 503,928.

To all whom it may concern.

Be it known that I, HERBERT N. WAYNE, a citizen of the United States, residing .at Vashington, District of Columbia, have invented new and useful Improvements in Inner Tubes for Automobile Tires, of which the following is a specification.

This invention relates to inner tubes to carry air pressure inside pneumatic tires; and the general object of this invention is to provide a means whereby the tube Wlll be rendered difficult of puncture; a further object of the invention is to provide a means whereby the walls. of the tube may be reinforced and strengthened in degree proportionate to the varying requirements of different service conditions; it is also an object to .apply the reinforcing means in sucha manner as to allow all necessary expansibility in the tube along normal lines of expansion when the tube is inflated in a casing; it is also a further object to provide an expa-nsible air-tube of such contour and construction as will be best adapted to conform, without additional temporary expansion, to the natural hinge of the tire due to the changing form of the tire where the casing comes in contact with the ground.

The constant flexing of the side walls of the casing at the point of road contact being the source of all frictional heat in the casing and inner tube.

The invention, its features, the manner of its construction and how it accomplishes its objects, will be bestunderstood from the following description, reference being had for this purpose to the accompanying draw- 1ngs Fig. 1 is a perspective view of a section of inner tube constructed in accordance with the invention.

Fig. 2 is a. perspective view of a modified form of construction of the tube.

Fig. 3 is a cross section of the improved tube.

Fig. 4: is a cross section of the improved tube as shown inflated within the casing.

Fig. 5 is a cross section view showing a depressed tire. in contact with the ground.

Numbers 10 and 11 in Fig. 1 indicate strips of calendered fibrous material having the longitudinal direction of the fibres in one strip lying in diagonal relation to the direction of the fibres in the next adjoining strip. Numbers 12 and 13 Fig. 2 indicate'fibrous material applied in in such a manner that two zones only, the longitudinal direction of the fibres in. one zone (12) lying at right angles to the longitudinal direction of the fibres in the other zone Number 14, Fig. 3 indicates an arched bulge in the upper side wall of the tube for the purpose hereinafter described. The dotted lines (15) indicate a modified form of construction hereinafter more fully described.

To accomplish the objects contemplated by my invention I prefer to use a v mix of fibrous material. such as asbestos or vegetable fibre, preferably cotton, and rubber. I have successfully used such a mix containing 25% of ground cotton fibre and 75% of rubber and sulphur.

In constructing the tube I may first apply an inner lining of pure rubber or other impervious material and then cover it with an outer layer, or layers, of the fibrous compound. I wish to here note that in the process of calendering a fibrous mixture or comound of the character described the short fibres of the shredded cotton are smoothed out in a general longitudinal direction as the mixture passes through and emerges from the calender rolls. The resulting sheet of fibrous mixture (or perhaps it is better to describe it by the usual technical namefibre compound) will therefore possess a fibrous grain similar to the grain structure of leather, also will in a large degree possess similar puncture-proof qualities, and because the binder element is rubber, it follows that such a sheet will be more elastic in transverse section than it will be in longitudinal section of the sheet. a sheet when vulcanized will offer much greater resistanceto any given degrees of tension force exerted upon it in a longitudinal direction than it will offer to a similar force in the other or lateral direction. It is these peculiarities, variable elasticity and resistance to puncture, which are possessed by In other words, such a suitably proportioned fibrous compound,

inner tube. Realizing the importance ofmaking 'suitable provision for expansion of the tube in all directions necessary to properly expand and fill the casing, I propose to lay varying layers of this fibrous compound the direction of the grain in each layer will lie at a different angle than that of the next adjoining layer, from each other.

' tires,

In my preferred construction I divide the cross sectional circumference of the tube into two or more zones, each zone having a greater degree of elasticity in one direction than in the other, with the-direction of maximum elasticity in one zone being in a different direction than the line of maximum elasticity in the next adjoining zone.

This may be accomplished by laying strips of calendered fibrous compound diagonally in relation to the length of the tube, each alternate layer being laid at an angle different to the angle of the adjacent layer, as in Fig. 1 or the whole of the tread-portion may be covered by, or wholly composed of, fibrous compound having the longitudinal direction of its fibres running in a general transverse direction and the rim portion covered by, or wholly composed of, fibrous compound having its fibres running in a general longitudinal direction, as in Fig. 2; a third modification might to advantage combine both' previous modified forms.

Fig. 3 shows a cross section of the preferred contour of my improved tube, the purpose of the arched bulges marked 14 in the drawing is to cause the tube at these points to follow the-natural elongation at the axis of the bend caused by the flexing of the casing where it comes in contact with the ground, as illustrated in Fig. 6.

In the illustration Fig. 5'is shown the same tube as inflated within thecasing under normal conditions.

To facilitate the emplacement of the tube within the casing I may mold the tube with depression. circumferentially around its inner pheriphery as indicated by dotted lines 15 in Fig. 3, thereby raising this inner circumferential portion away from the rim and this reducing liability to pinch the tube when the tire is mounted on the rim.

I havedescribed and illustrated my invention as especially applied to inner tubes, but-it is to be understood that, of course, the invention is equally applicable to liners, reinforcements, etc., where this material may be used.

Having described the various functions and methods of construction of my im proved inner tube, what I claim as new is 1. An inner tube for pneumatic tires conlongitudinal direction of the fibres in the next adjoining zone.

2. An inner tube for pneumatic tires having a body portion composed of fibrous material in mixed combination with rubber, the direction of the fibre being trans versely to the tube thus permitting expansion longitudinally and restricting the expansion laterally.

3. An inneu tube comprising an inner lining of rubber; a layer of calendered fibrous material mixed with rubber and applied in two or more zones, the general direction, longitudinally of the fibres in one zone, lying at a different angle to the longitudinal direction of the fibres in the next adjacent zone, the whole being vulcanized to form a unitary structure.

4:. In combination, a tire casing and an inner tube, the inner tube consisting of a body portion composed of an inner lining of soft rubber tube stock; a layer of calendered fibrous material mixed with rubber covering the inner lining and applied in two or more zones, the general direction longitudinally of the fibres transversely of the tube,

the completed tube being vulcanized as a unitary whole.

5. In combination, a tire casing and an inner tube, the inner tube having longitudinally arched bulges circumferentially' of the tube around the upper side walls;'a layer of soft rubber tube stock; a layer of calendered fibrous material mixed with rubber and applied transversely of the tube, and the completed tube being vulcanized as a unitary structure.

6. In combination, a tire casing and an inner tube, the inner tube having longitudinal arched bulges circumferentially of the tube; an inner lining of soft-rubber; an outer layer of fibrous material in combination mixed with rubber, the whole being vulcanized together as a unitary structure.

In testimony whereof I afiix my signa= I ture.

" HERBERT N. WAYNE.

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