US 2980161 A
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April 18, 1961 F. A. HOWARD CONTINUOUS MECHANIZED PRODUCTION OF TUBELESS TIRE SAFETY RINGS Filed Dec. 27. 1954 4 Sheets-Sheet 1 llll'ly |A||| mwzE 353% 5 1 a a; mm wlzrrw DUZMOM n0 @IFGZUJ FDU @JJOM $440M UZZLMOm JUZZQIU DZQ MDNOL- INVENTOR. FRANK A. HOWARD ATTORNEYS April 18, 1961 F. A. HOWARD CONTINUOUS MECHANIZED PRODUCTION OF TUBELESS TIRE SAFETY RINGS Filed Dec. 27. 1954 4 Sheets-Sheet 2 INVENTOR. FRANK ,4. Ho WARD ATTORNEYS April 18, 1961 CONTINUOUS MECHANIZED" PRODUCTION OF TUBELESS TIRE SAFETY RINGS Filed Dec. 27. 1954 F. A. HOWARD 4 Sheets-Sheet 5 l l I l INVEN TOR. FRANK A. HOWARD A T TORNE Y5 April 18, 1961 F. A. HOWA'RD CONTINUOUS MECHANIZED PRODUCTION OF TUBELESS TIRE SAFETY RINGS 4 Sheets-Sheet 4 Filed Dec. 27. 1954 INVENTOR. FRANK A. Ho WARD ATTOR EYS United States Patent 2,980,161 Patented Apr. 18, 1961 CGNTINUOUS MECHANIZED PRGDUCTION F TUBELESS SAFETY RINGS Frank A. Howard, '30 Rockefeller Plaza, New York,N.Y.
Filed Dec. 27, 1954, Ser. No. 477,823
'4 Claims. (Cl. 1'5414) This invention relates to the continuous mechanized production of tubeless tire safety rings such as those described in my prior application for patent Serial No. 134,957 filed December 24, 1949, now Patent No. 2,811,189. 7
The invention will be fully understood from the following specifications taken in connection with the accompanying drawings, in which Figure 1 is a schematic diagram and production flow sheet showing the sequence of the various operations involved.
Figure 2 is a diagrammatic side elevation of the torus forming assembly.
Figure 3 is a diagrammatic cross section through the torus showing the manner in which the marginal channels and crown of the ring are formed.
Figure 4 is a fragmentary plan view of the twoply strip at a cut point.
Figure 5 is a similar view showing the arrangements for an alternative simplified cutting operation.
Figure 6 is a side view of a segmental splicing and vulcanizing form.
Figure 7 is an enlarged cross section through a sheet metal form of this type taken on the line 7-7 of Figure 6.
Figure 8 is an enlarged section through one channel taken on the line 88 of Figure 6 and showing the construction used when a segmental torus formed with an attached channel ring is used for the splicing and vulcanizing operation.
Referring to Figure 1, the numeral 1 indicates a reel on which there has been Wound a continuous two-ply strip of textile material of the requisite width, the twoplies having previously been bonded together'and their outer surfaces coated by an uncured rubber compound.
The production of such strips in one or more plies is well understood in the tire industry, and the strips are wound upon reels over an intermediate liner of. muslin which prevents successive turns on the reel frombonding together. For the purpose of fabrication of my Omegacross-section torus ring, the textile materials used may be either square-Woven materials or cord fabrics made up of closely spaced parallel strands of cord loosely held together by widely spaced fine cross threads.
Where square-woven fabric is used, it may be cut on the bias so as to be more readily stretched and compressed in both directions during the forming process. Where cord fabrics are used they will also be cut on the bias and laid with the cords at opposite angles. For the special purposes of my invention it is desirable to incorporate in the two-ply strip at regular intervals corresponding to the length required to produce one Omega ring, aply-separ ating cross strip. The cross strip will have surfaces which do not bond to the ply surfaces which it separates during the forming process. Such a cross strip may be made of coated paper. The two-ply strip is designated 2 and the cross strips are designated 3. As shown in Figures 4 and 5 at 2 the rubber coating or facing of the plies should be extended over the raw edges sufficiently to seal the ends of the cords or the edges of the strips of the textile material. The rubber coating on the margins of the strip may be thickened as shown in my prior application Serial No. 134,957, either on the outer face or on both faces of the strip, so that the marginal flange of the finished safety ring will form a sealing gasket between the face of the tire bead and the rim flange. Also a piping may hepre-formed on the edges of the strip, either with or without a stiffening core of cord or wire. These details form no part of the present invention and are men tioned only to indicate that their use is not in anyway proscribed by the fabricating process and equipment of the present invention.
As will be seen from Figure 1, the strip is fed from the roll 1 to the forming assembly over bellying rolls which are designated 4, 4, 4". The construction of these rolls is identical except that the central portions decrease in width and increase in diameter as shown in Figure 1 to accomplish a progressive bellying of the strip 2. During this bellying operation the margins of the strip are held flat by supplementary upper rolls 5 which grip the margins of the strip 2 against the necks of the rolls 4, 4 and 4". As the strip feeds over the series of bellyin-g rolls it ass tines a U-shaped cross section with flat margins and consequently its width between the margins is greatly reduced as shown in Figure 1. Turning to Figure 2, the last of the bellying rolls is shown at 4 on the right-hand side, the neck of this roll serving as a flat surface to support the flat margins of the strip which is held in contact by the upper roll 5. Leaving the last set of bellying rolls the flat margins of the strip feed on to the flanges 6 of the main forming rolls 8. They are gripped against these flanges by the channel forming rolls 9, and 9". The necks of the channel forming rolls are of constant diameter but the outer portion of each roll is of progressively increasing diameter as shown in Figure 2, and thus serves to press the strip downward toward the inner shoulders 7 of the rolls 8, the diameter of the last channel forming roll 9" being sufficient to force the strip into contact with the inner shoulder 7 as shown in Figure 3. Either the main rolls 8 or the channel rolls 9 or both may be positively rotated at the desired speed to advance the strip through the forming assembly.
While the bellyin-g rolls have caused the strip to assume a U-shaped cross section with flat margins and the channel forming rolls 9 have pressed this flat margin into the desired final channel shape, there is one additional operation which must be performed. As the strip feeds around the main rolls 8, the crown of the strip designated 10 is necessarily drawn radially inward. To form a torus this crown 10, and also the side walls, to a lesser degree, must be stretched by an amount proportional to the difference between the inside and outside diameters of the torus. For the production of a safety ring this stretching action at the crown must be from about 30 to 50% of the original length'of the strip. To carry out this stretching action I provide spinning or stretching rolls 11 as shown infull lines in Figure 3. Each of these rolls is mounted freely upon a shaft carried by a spider arm 12 secured to a rotating hub 13 journaled on a fixed crank pin 14 carried by a fixed shaft 15 which passes through the center of the right-hand roll 8. Surrounding the fixed shaft 15 there is a driving sleeve 16 on the inside end of which there is fixed a driving gear 18 which meshes with a planet pinion 17 carried by a fused stud on the hub 13. The planet pin-ion 17 meshes with a ring gear 19 fixed to the inner face of the roller 8. Through these Connections the driving sleeve 16 may be rotated to turn the hub 13 on the shaft 14 and thus cause the spinning and stretching rollers 11 to turn in a circle which intersects the path of the crown 10 of the strip 2, as shown in Figure 2, and stretches or spins it outward progressively as it moves around the circumference of the main rollers 8. During this crown-stretching or crown-spinning operation, in which the formed strip is converted into a torus form, it is necessary that the margins of the strip be gripped firmly against the internal shoulders 7 of the channel and torus forming rolls 8 as shown in Figure 3.
In Figure 2 I have illustrated the entire channel-form ing and crown-stretching operation as being completed within an arc of approximately 90 of the rolls 3, but it will be understood that the arc may be widened up to 180 or more.
Also, for simplicity of illustration 1 have shown the bellying of the strip as being carried out while the margins are held flat by rolls 5, and I have shown the channel-forming operation as being carried out over the same rolls 8 on which the crown-stretching is carried out. These various operations may if desired be separated. For example, the strip 2 may first be bellied by a single roll 4" without necks, and the-strip edges subsequently turned outwardly to form the fiat margins by a separate set of margin-forming rolls. Also the channels may be formed by passing the bellied strip with flat margins over separate channel-forming rolls, and then feeding the bellied and channelled strip to the crown stretching rolls 8. The channelled margins must, however, be held in place by the channel rolls 9", as shown and described, during the crown-stretching operation. Also the marginal channels of the strip, if preformed on a straight strip so as to eliminate the rolls 9, 9, must be slightly re-formed to the torus shape. This will be done automatically by the rolls 9 as the strip passes over the rolls 8.
As indicated in Figure 1 the continuous strip 2 leaving the forming assembly may be cut in lengths suitable for the production of the finished rings. Referring to Figures 4 and 5, two methods of cutting are illustrated. The greatest economy of material is obtained by cutting the two plies separately and at opposite angles parallel with the cords, at the point where they are separated by the ply-separating strip 3 as shown in Figure 4. By using a wider ply-separation strip 3 and by some sacrifice of material, a straight cut can be made through the center of theply-separating strip as indicated in Figure 5, and in Figure 2 where the cut point is marked 20. This leaves suflicient material on either side of the cut for the eventual diagonal cuts to be employed at the splicing station if the two-ply strip is made of cord. It will be understood, however, that my invention is not limited to the use of cord fabric nor diagonal splicing and that I have illustrated these alternatives in Figures 4 and 5 merely for the purpose of making the invention more clear.
From the cut point at the end of the forming assembly, the cut lengths of strip, which have already assumed the torus form, are delivered to the ring splicing station. At this station, each cut length is manually mounted over a segmental splicing form 21 which may be made of sheet metal. The splicing form has channel margins 22 adapted to receive the channels of the formed ring and these channel margins are continued beyond the end of the center segment to form a complete circle, which may be split at a lower point as indicated at 23 in Figure 6. The-split 23 permits the channels 22 to be sprung inward sufiiciently to remove the safety ring from the form after vulcanizing.
To make the splice, the cut length of formed strip is mounted on the form with the ends in the approximate center of the upper segment 21. The channels of the ring having then been mounted in the complete channels 22 attached to the segmental form, the exact dimensions of the ring are fixed and the splice is made accordingly. If the ring has been previously cut on a straight line 20 as indicated in Figures 2 and 5, there will be a considerable overlapping of the ends, and in the splicing operation there is ample material to make a smooth splice, as is well understood in the art. After the splice has been made the entire safety ring may be locked on the form by separate complete channel rings 24 which may be pulled tightly together by a fastening 25.
If desired, there may be employed also an outer segmental form 26 to press together the spliced ends of the ring and hold them pressed together during the subsequent vulcanization. At the time of splicing, the rivet 27, which contains the air hole for controlled leakage of air through the safety ring 28, may be installed, or this operation may be performed separately before the open ring is mounted on the splicing form. The segment 21 should have a sufiicient are so that the free body portions of the safety ring will drape or fall naturally in a position approximating the final shape as indicated in the dotted line 29 in Figure 6.
On the completion of the splicing operation the splicing form with the completed ring mounted thereon may be hung over a hook 31 carried by a conveyor chain 32 which moves at low speed through a vulcanizing tunnel 33. Within this tunnel the rings are subjected to heat by radiation or by hot gases, or both, for a sutlicient length of time to effect a cure. During the curing operation the smooth finish and exact dimensions of the channel portion of the safety ring are ensured by gripping the channels between the rings 22 and 24- as shown in cross section in Figure 8. The channels of the safety ring are the only portions thereof in which great accuracy of dimensions and perfect smoothness of the surfaces is required.
As the chain 32 emerges from the vulcanizing tunnel the finished rings are removed from the forms, and the return length of the chain delivers these forms back to the ring-splicing station.
It will be noted from Figure 3 and from Figure 7 that the strip may be formed as a torus ring of U-section, that is with straight or slightly divergent side walls, rather than of Omega section with horse-shoe shaped walls, and vulcanized in this same position. This will not prevent the finished ring from assuming its final Omega cross section, shown in my prior patent application Serial No. 134,957, when it is mounted between the tire and rim. The forming and even the vulcanizing of the ring with a U-cross section slightly wider at the base than at the crown greatly simplifies the forming operation and also simplifies thev construction and handling of the splicing and vulcanizing forms. If desired, however, the splicing form may be of the exact Omega cross section of the mounted ring as shown in my prior application.
While the operation producing my Omega cross section safety ring, as above described, is essentially continuous and mechanized, it will be apparent that the production operations naturally divide themselves into sections which do not need to be synchronized. Thus the fabrication of the complete two-ply strip mounted on the reel, as shown in Figure 1, constitutes a first, independent stage of the operation, and completed reels of strip may be prepared in advance and stored; The strip-forming operation constitutes a second stage which, while continuous in itself, need not be synchronized, either with the production of the strip or with the splicing of the cut rings which emerge from the forming station. These cut rings may likewise be stored and transported to other locations for the next operation of ring splicing. The ring-splicing operation is essentially a manual operation and as such it may be most efficiently carried on in one or two shifts per day since it requires new capital investment only for the splicing forms. The final vulcanization of the rings is essentially a continuous operation but need not be synchronized with the splicing of the rings. Thus the ring splicing might be carried on on one shift per day, whereas the vulcanizing tunnel might operate continuously on stored rings.
If desired the formed strip leaving the forming assembly may be passed continuously through a vulcanizing tunnel and cut into lengths only as it emerges from the tunnel. Because of the spacing strips 3, the plies will not bond together during this vulcanizing. The cut lengths of vulcanized and formedstrips may then be delivered to the ring-splicing station, as before described, and the ring completed by making the splices. The overlapped ends of the spliced plies may be cemented together with a self-curing cement. While a cement joint of this kind would not be satisfactory for a tire, it can be made sufficiently strong and reliable for usein a safety ring where it is subjected to full internal pressure and to external loading only in the event the tire blows out, and then for very short periods and in only a few instances in the life of the ring.
In the foregoing I have described in considerable detail the machines and operations involved in the continuous mechanized production of safety rings for tubeless tires from the materials heretofore used for this purpose, that is textile fabrics bonded and coated with rubber. Substantially the same general metho'ds and machines may also be employed with quite different materials however. For example, the strip 2 may be made of plastic. Plastic materials suitable for this purpose include nylon (a copolymer of adipic acid with a diamine), Mylar (a polyester of terephthalic acid and glycol), Parapal (co-polymer of isoprene and styrene), polymers of vinyl chloride or vinylidine chloride, polymers of ethylene, and similar plastics which may be pre-formed into strong, flexible sheets.
Strips of flexible sheet plastic having the necessary, workability, strength and high softening point may be given the desired shape by forming and stretching rolls as described. Depending upon the properties of the plastic sheet used, the operation may be carried out at normal room temperatures, or the rolls may be heated to the temperature necessary to shape the material. Such heating may be done in any suitable way, such as by electrical heating elements incorporated in the metal of the rolls or mounted in juxtaposition to them, or by encasing the entire assembly of strip and rolls in a hot chamber and cutting the formed strip as it is cut off after passing over the rolls 8.
The plastic strips used may be of uniform thickness, or they may be preformed so as to be either thicker or thinner on the margins. Pre-formed composite strips may also be employed, as for example strips of plastic reinforced With a textile strip on one side or on both sides or between two plastic strips. Also composite strips may be used having marginal portions of textile material for strength and resistance to chafing, or of rubber to form air seals between the tire beads and the rim, or of both textile and rubber, or of wide textile strips covering the complete channel section and rubber strips only Wide enough to form the vertical faces of the outer flange. The di-isocyanates form useful cements for bonding rubber to plastic.
The above will indicate the range of materials and of details of construction which may be used to pre-fo'rm the strip 2. Whatever be the specific composition and construction of the pre-formed strip it may be converted into a safety ring for tubeless tires by the general methods shown and described in detail as applied to a two-ply strip of textile material bonded and coated with rubber-like material. in the event a plastic which does not need to be thermally set is used, instead of rubber, however, it will be obvious that the vulcanizing step is unnecessary. The exact technique used in the operation of splicing the ends of the ring over the splicing form also may be modified by the nature of the strip. For example, the splicing of the ends over the splicing form may be carried out mechanically by thermal fusion of the overlapping portions, using a high-frequency plastic seaming appliance of the type commonly used for sealing the seams of sheet plastic covers. Or the overlapping sections of a plastic ring may be cemented, and to make a smooth splice,
, 6 especially in the outer flange of the marginal channels, these portions of the overlapping ends may be skived or beveled, as by a heated pressure tool, before cementing them together. Numerous examples of thermosetting cements or plastics for splicing the ends of the strips may be found in the section on Heat Sealing Adhesives, pages 197 et seq. in the fEncyclopedia of Chemical Technology, volume 1, Kirk and others (Interscience Encyclopedia Inc., New York, N.Y.) 1947.
While I have shown and described one embodiment of my invention in the foregoing, together with many optional modifications thereof, it will be understood that these details are only for the purpose of making the invention more clear and that I do not regard the invention as limited except in so far as the limitations are included Within the terms of the accompanying claims in which it is my intention to claim all novelty inherent in the invention asbroadly as is permissible in view of the prior art.
What I claim as new is:
1. The method for continuously fabricating a toroidal safety ring for a tubeless tire, the ring having a circumferential opening on the inner periphery thereof and having marginal outturned channel sectio'ns, comprising the steps of passing a flat flexible strip through bellying rolls while gripping the margins thereof to effect a progressive bellying of the strip causing it to assume a U-shaped cross-section with flat margins, passing the bellied strip through channel-forming rolls progressively to deform said flat margins into out-turned channel sections, feeding the bellied and deformed strip through stretch rolls along an arcuate path to stretch out the central longitudinal portion of the strip While securing the outturned channel sections thereof, cutting olf lengths of the strip so stretched, and joining the ends thereof to form said toroidal safety ring.
2. The method for continuously fabricating a toroidal safety ring for a tubeless tire, the ring having a circumferential opening on the inner periphery thereof and having marginal out-turned channel sections, comprising the steps of passing a flat flexible strip containing a thermosetting plastic through bellying rolls while gripping the margins thereof to etfect a progressive bellying of the strip causing it to assume a U-shaped cross-section with flat margins, passing the bellied strip through channelforming rolls progressively to deform said flat margins into 'out-turned'channel sections, feeding the bellied and deformed strip through stretch rolls along an arcuate path to stretch out the central longitudinal portion of the strip while securing the out-turned channel sections thereof, cutting off lengths of the strip so stretched, joining the ends thereof to form said toroidal safety ring, and conveying said toroidal safety ring through a heating zone in which the plastic is thermally set to cause the ring to retain its form while remaining flexible.
3. The method for continuously fabricating a toroidal safety ring for a tubeless tire, the ring having an Omegashaped cross-section comprising the steps of continuously passing a flat flexible strip through bellying rolls While gripping the margins thereof to effect a progressive bellying of the strip causing it to assume a U shaped crosssection with flat margins, passing the bellied strip through channel-forming rolls progressively to deform said flat margins into out-turned channel sections, feeding the bellied and deformed strips through stretch rolls along an arcuate path to stretch out the central longitudinal portion of the strip while securing the out-turned channel sections thereof to cause said strip to assume an Omegas'haped cross-section, cutting the continuous strip having the Omega-shaped cross-section into lengths substantially equal to the circumference of the ring, and joining the ends of the lengths to form said safety ring.
4. The method set forth in claim 3, wherein saidstrip is formed of heat moldable material and wherein said 7 strip being shaped is heated to cause it to retain the configuration imparted thereto. 5
References Cited in the file bf this patent v UNITED STATES PATENTS 311,409 Butz et a1. Jan. 27, 1885 993,308 Lamont May 23, 1911 1,888,702 Snyder Nov. 22, 1932 2,140,213 Tegarty Dec. 13, 1938 2,253,759 Burkley Aug. 26, 1941 2,294,621 Kraft Sept. 1, 1942 Ryan Apr. 25, 1950 Burk'ley -Tu'ly 10, 1951 Webber Dec. 30, 1952 Slezak Jan. 12, 1954 Perkins Dec. 28, 1954 Gaubert et -al Oct. 30, 1956 Wills Dec. 4, 1956 Simpson May 28, 1957 FOREIGN PATENTS France Dec. 16, 1953