The opinion of the court was delivered by: WATKINS
This is an action for alleged infringement by defendant of plaintiff's
patent No. 2,587,470, issued February 26, 1952, on an application filed in the Patent Office on December 14, 1946. For convenience, the patent in suit will sometimes be referred to as the Herzegh patent.
Jurisdiction under the patent laws, including sale and use by defendant within the District of Maryland of products allegedly embodying the invention of the Herzegh patent, and maintenance by defendant of a regular and established place of business within the District, was asserted and proved. 28 U.S.C. § 1338; 28 U.S.C. § 1400(b).
A brief description
of a typical tire is necessary to an understanding of the state of the art at the time of plaintiff's alleged invention, and the improvements claimed in the Herzegh patent.
A conventional tire assembly pertinent to this suit consists of a tire casing (usually called simply a tire), together with an inner-tube, and a one-piece metal rim.
The tire has a tread or wearing surface and a sidewall covering the outer part of the tire to protect the body of the tire, on a carcass containing plies, cords and beads.
The tread runs on the road, and may be either integral with the sidewall covers or a separate part adjoining the sidewall covers. Usually, the tread and sidewall covers are composed wholly or mostly of natural rubber or of butadiene-styrene synthetic rubber (until recently known as GR-S). Both of these are more abrasive resisting than butyl rubber.
GR-S rubber is a synthetic rubber very like natural rubber, with which it is compatible, so that they can be blended or adhered one to another. Butyl rubber is also synthetic, but less abrasive resistant than either natural or GR-S rubber, and is incompatible with them. Butyl rubber also has a higher 'permanent set' and less resiliency than natural rubber or GR-S; that is, it tends to remain in the shape in which it may have been deformed or distorted, rather than returning to its previous shape. Butyl is, however, only about one-tenth as permeable by air as natural rubber.
The carcass is composed of plies (sheets of cord fabric, coated with rubber) containing cords. There are usually four, but sometimes six, plies in passenger car tires. Each ply is a layer of parallel cords coated and surrounded by rubber. The cords are strong, flexible threads, which may be made of cotton, nylon, or other fabric, or wire, but at present are usually rayon. The plies lie on top of each other, the innermost ply being inside the carcass, and the outermost ply is on the outside of the carcass just under the tread. They are numbered in that order, the innermost being referred to as the first ply. The cords in adjacent plies cross the center line of the tire at the same angle, but in opposite directions.
The beads contain bundles of wires, bound together and placed in the margins of the sidewalls, which rest against the flanges of the metal wheel rim. The wire beads form a non-extensible anchorage for the plies, which are anchored by wrapping them around, or partially around, the bead. This is known as a 'ply lock'. In the 'conventional' ply lock, plies 1 and 2 come underneath the bead on the inner side of the tire and then turn up around it on the outside. Ply 3 comes down the outer side of the tire, turns under the bead and up on the inner side a short distance. Ply 4 follows the same course, except that it terminates under the bead.
The bead portion of the tire is the portion in which the beads are located. The bead toe is the sharp corner on the inside of the tire, and the bead heel is on the outside where the bead rests against the rim flange.
Terminology is not completely consistent. Thus the word 'sidewall' is sometimes used to refer to the sidewall cover, which is actually the surface layer only of the sidewall. Similarly, the word 'bead' is sometimes used to refer to the wire ring only, or to the wire, together with its wrappings, and the word 'grommet' is sometimes used with the same meaning.
Sometimes a 'chafer' or 'finishing' or 'rim seal' or 'bead sealing' strip is placed between the beads and the rim flange to prevent the plies around the beads from being chafed or rubbed during operation.
The ordinary rim on passenger car tires is now, and for many years had been, of the one-piece drop-center straight-side flange type.
In the conventional commercial automobile tire produced before 1948, an inner tube was used. This, and not the carcass, was designed to be the air retaining member. But at least until the advent of the butyl rubber inner tube,
substantial loss of air occurred through the inner tube. As the rubber elements of the tread and plies were generally of the same basic material as the inner tube and their combined thickness of rubber was greater than that of the inner tube, and as the permeability of rubber is directly proportional to its thickness, such air escaping from the inner tube would be trapped, unless some venting was provided. Trapped air would tend to diffuse into the plies, and cause the formation of blisters and the separation of the plies, resulting in early failure of the tire. It was therefore customary to provide grooves in the base of the beads, or ribs on the surface of the inner tube, all leading to the valve stem, to allow the escape of trapped air.
A satisfactory tubeless tire required a lining more nearly impermeable to air than the carcass of the tire, and an effective air seal between the tire beads and the rim.
Claim 19 was selected by plaintiff as typical of the claims in suit.
It reads as follows:
The attached exhibit-diagram of plaintiff's present
tubeless tire will be helpful to an understanding of the problems in this case.[SEE ILLUSTRATION IN ORIGINAL]
As stated by plaintiff's counsel:
'The invention of this claim (19) consists of a tire of ordinary body and sidewall construction on an ordinary wheel rim with flanges, which, when inflated with air, will operate satisfactorily, because of the specific kind of sealing ribs and the specific kind of liner described in the claims.'
'* * * There is no doubt that each feature in the Herzegh combination was known to the art. However, it is clear that the specific arrangement and placement in combination, which he taught and embraced in his claims and which the proof will show has solved factually the obviously difficult problem that confronted tire manufacturers, had never been suggested. Herzegh demonstrated that his specific placement and prescribed relationship of conventional tire, conventional rim, impervious liner and sealing ribs furnished a complete answer to the problem. This produced a new and useful result which had not been previously accomplished.'
It is therefore unfortunately necessary
to consider in some detail just what are the 'specific kind of sealing ribs'; the 'specific kind of liner'; and the 'specific arrangement and placement in combination' which Herzegh taught.
An object of the invention is 'to provide a high resistance to diffusion of air into and through the wall of the tire; and to provide this high degree of impermeability' without objectionable heat.
A further object of the invention is 'to provide for sealing * * * between the tire bead portions and the rim flanges * * *.'
The specifications describe the sealing means as follows:
'Provision is made for sealing the tires at the straight-side rim flanges 12. The axial outer face of the bead portion is formed with a plurality of ribs 24, 24 extending in a circumferentially continuous manner about the tire. These ribs are of resilient rubber or other rubber-like material and preferably are molded integrally with the bead portion of the tire wall. The ribs are urged in the axially outward direction against the rim flange by the inflation pressure within the tire and effect a seal not only against the leakage of air from within the tire past the bead portion, but also a seal against the entrance of water, soil or other foreign matter from without, and the sealing in this manner is advantageous further in being maintained effectively even under conditions of rocking of the bead portions under extreme deflections of the tire. Further, I have found that it is possible to insert tire tools between the rim and the bead portions for assisting in demounting the tire without injury to the ribs, the heel of the bead portion taking the prying action of the tool.
It should be noted that the only statement as to the material of the ribs is that they are 'of resilient rubber or other rubber-like material.' This does not in terms exclude the use of butyl for the ribs, for butyl-type rubber, prescribed for the liner in all claims in suit except Claim 20, is described as exhibiting good properties of 'flexibility and resilience.' Butyl is admittedly a 'rubber-like material.'
The liner material is described as follows:
'The butyl type of synthetic rubbers, which are copolymers of isobutylene and a diolefine such as butadiene or isoprene, are found to be well suited for the purpose of this lining layer 25. The lining layer of such butyl type rubber at the inner face of the tire and adhered to the rubber of the tire wall so as to constitute an integral part of the wall is found to render the walls highly impervious to the air under pressure directly against it, so that diffusion into the wall such as would be likely to cause blisters and ply separation is effectively prevented. At the same time such butyl type rubber exhibits good properties of flexibility and resilience and gives good results even when the layer is relatively thin, so that this lining layer together with the fabric reinforced rubber composition normally used in the tire body are as a composite unit well able to withstand rapid cyclic flexing stresses in use.
'As an example, intended as being illustrative rather than wholly limiting, the following butyl type rubber composition, in a thickness of the lining layer 25 of the order of .04 inch and even lower, depending on the type of service, has given excellent results for the purposes of this invention in extensive tire tests:'
This single example, in which the only rubber component is butyl rubber, embodies the recipe used in regular production of plaintiff's butyl inner tubes since at least as early as December, 1945. The liner thickness of .04 inch compares with the .044 thickness of an inflated inner tube.
The extent and termination of the liner, stressed as a crucial part of the invention, is stated in the specifications as follows:
'The lining layer 25 preferably is extended down to the bead portions, around the toe 26 of the bead portion and to the heel 27.'
The drawings show, and plaintiff's commercial production for the first year embodied, a liner completely covering the inner surface of the tire body from toe to toe and also the inner (or radially innermost) surface of the bead, i.e., the base of the bead, from toe to heel. That is, the butyl type rubber liner extends along the base of the bead, in engagement with the rim base from the bead toe to the bead heel. The rim-flange engaging surface of the bead in such case has no butyl liner protection, although it is subject to full inflation pressure of the air at all points below the lowermost rib. This disclosure therefore did not suggest means for preventing the escape of air into the body of the tire between the outer edge of the butyl lining at the heel, and the first or lowermost rib. In this area the ply cords are closest to the surface and most likely to be exposed, especially as some displacement and flow of rubber is likely to occur during vulcanization. A ply cord exposed to air under inflation pressure would act as an 'air wick' and probably result in blisters and ply separation.
In summary, the specifications teach, and Claim 19 of the Herzegh patent claims, as to the two alleged novel elements and their relationship, as follows:
The specification discloses ribs of 'resilient rubber or other rubber-like material' for sealing 'against the leakage of air from within the tire past the bead portion' and against the entrance of foreign matter from without.
Claim 19 specifies the ribs as 'between the bead portions' of the tire body and the 'flanges' of the rim.
Claim 19 also says that the ribs are 'of the same material as the sidewalls of' the tire body.
The Herzegh patent teaches that the rubber tire wall should have a lining layer 'of suitable flexible, durable and relatively impermeable material to prevent excessive diffusion into and through' the tire wall. The patent then states that butyl type rubbers 'are found to be well suited for the purpose of this lining layer', and a single example of a butyl type rubber composition
is given, which is the same as plaintiff's butyl inner tubes.
Claim 19 is for a 'relatively thin lining of substantially impervious
butyl type rubber composition adherent to' the body.
The patent teaches a liner 'preferably extended down to the bead portions, around the toe * * * of the bead portion and to the heel * * *.'
Claim 19 describes the liner as 'completely covering the inner surface' of the tire body and 'extending continuously from one bead portion to the other and terminating short of the outer surfaces of' the 'ribs on said bead portions.'
In place of a butyl inner tube in a tire carcass vented to the outside air, the Herzegh patent in effect has used one-half a butyl inner tube to line the entire inside of the carcass and extending to the bead heel; has used the drop center rim for the other half of the air container (sealing the valve stem in the rim); and has molded ribs into the side walls in the area where such side walls engage the rim flanges.
Has this device been anticipated by the prior art; is it a novel combination of old and well-known elements, or an aggregation thereof; and if validly patented, has it been infringed by defendant?
Prior Art -- Patents and Work on Tubeless Tires.
Plaintiff offered in evidence a book of sixty-six patents granted during the period 1903-1949, most of which relate to pneumatic tires without inner tubes. In considering these, and also the work whether by plaintiff, defendant, or others, on tubeless tires prior to the Herzegh application (December 14, 1946), two most significant facts must be borne in mind. First, the present drop-center straight-side flanged rim did not come into general use until 1925. The rims in use before that time, whether of the 'clencher' type, or the myriad of other types of rims, often were of split construction, and did not purport (or need) to be air tight. Therefore some of the inventions were concerned primarily, or as a necessary incident, with the sealing of the rim elements to each other.
Second, butyl rubber, a synthetic material having physical properties of elasticity and plasticity resembling those of natural rubber, manufactured by copolymerizing isobutylene with a diolefin, although developed by a subsidiary of Standard Oil Company of New Jersey in the late 1930's, was during the war years in short supply and under Government control. It was not until 1946 that restrictions on the use of butyl rubber for civilian purposes were lifted. Early in 1942 experimental quantities of butyl rubber were made available to the tire industry in the United States. Shortly thereafter inner tubes of butyl were manufactured and tested, which included tests by the United States Bureau of Standards. The reports of such tests, showing that butyl inner tubes were far less permeable to air than 'rubber' inner tubes, were circulated to the plaintiff and other rubber companies in the spring of 1942.
By 1944, large numbers of inner tubes were made of compositions in which butyl rubber was the sole rubber constituent. Therefore, while the early patents on tubeless tires called for a 'liner' in the carcass, such liners were of the only compositions then available -- natural rubber, with or without fabric or other strengtheners. These would 'work' insofar as the prevention of diffusion of air into the plies is concerned. The thickness of the rubber liner (which would have to exceed that of the tread) would have made such tires
expensive and heavy, would have impaired their flexibility and resilience, and would have led to overheating in operation.
This book of patents offered by plaintiff does show, however, that the questions of a liner and of a seal had been considered by many workers in the field of pneumatic tires, and embodied in many of the old patents.
Of significance on the need for liners (and in many instances seals) are:
Seddon -- No. 747,001, application March 17, 1903, patented December 15, 1903. A pneumatic tire of canvas cemented inside and outside with rubber.
Duryea -- No. 776,650. Application January 16, 1904, patented December 16, 1904. A pneumatic tubeless tire, in which the bottom surface of the air-retaining chamber was the 'iron tire' or rim. The patent recited:
'While the ordinary tire-casing if given an inner coating of rubber suffices ordinarily to hold the air properly, it is preferable that the rubber should be thicker, or slightly corrugated along the edge of the tire, as shown in Fig. 1A. These corrugations being of soft rubber flatten down under pressure and insure that any roughnesses or depressions in the metal are closed and make a more effective joint than if flat rubber alone is used * * *.' (P. 3, ls. 59-69).
The claims were for an air-tight inner wall; an air-retaining shoe; and 'inner air-retaining lining'; and an air-tight inner wall.
Neary -- No. 779,731. Application May 28, 1904, patented January 10, 1905. A 'vehicle tire' in one form of which 'the inner air-holding tube may be omitted,' the rim base constituting part of the air container. The tubeless tire was to be formed by
'* * * lining the inner surface of the members 8 (side flanges) and the outer surface of the rim 6 lying between them with a layer of soft rubber or equivalent material * * * and extending the rubber surface of the tire shell in a thin layer entirely around the rim-engaging surface of the base, * * * and also over the inner surface of the shell, so as to render the inner wall of the shell and the interfitting surfaces of the tire base and rim air-proof under the internal pressure by the intimate contact of substances capable of making an air-proof joint when forced together under sufficient pressure.' (P. 2, ls. 60-69).
Duryea -- No. 875,053. Application April 8, 1907, patented December 31, 1907. Tire held by positive attachment to rim whether or not inflated. 'My preferred construction, however, is to line the tire with a layer of rubber of sufficient thickness to retain the air without the use of the removable inner tube * * *.' (P. 2, ls. 49-53).
Hartman -- No. 927,793. Application February 28, 1908, patented July 13, 1909. 'Pneumatic Tire and Clamping Means.' A tire with inwardly extending edge-folds, chiefly of canvas, but internally and externally covered with rubber, one edge-fold having a small rubber or pliable sealing flange seat held against the other by internal air pressure, with no inner tube.
Clark -- No. 1,079,397. Application June 17, 1913, patented November 25, 1913. A vehicle tire having flared channel bands, with flexible material, preferably rubber, to prevent water and dust entering the space between the bands and the casing.
Allen -- No. 1,134,660. Application August 28, 1914, patented April 6, 1915. A pneumatic tire on a conventional wheel and rim with a locking flange, and with an inflation valve fitted so that no air can leak. The object is stated (P. 1, ls. 34-52):
The lining and seal are thus described, (P. 1, ls. 60-80):
'In the present embodiment of my invention I provide the casing C with an inner rubber lining a cured to the casing wall, said lining extending over the inner faces of the beads b forming the edges or margins of the casing, the outer faces of the beads as well understood, being engaged by the flanges E, E', above referred to. Spanning the distance between the beads b, b, of the casing C, and cemented or otherwise secured air-tight to the inner lining a of the casing, is a web of rubber d, the marginal portions or sides of which engage the lining a the full extent of the inner faces of the beads b, b. This web together with the lining a of the casing forms an air-tight annular chamber P about the rim of the wheel, and is an admirable substitute for the prevailing inner inflatable tube of the conventional pneumatic tire.'
Evans -- No. 1,154,497. Application October 2, 1914, patented September 21, 1915. Along the points of contact of the tire and wheel rim (the latter being a part of air chamber), forming rings may be placed in the bottoms of channels, the rings being of flexible materials such as rubber. The outer sides of the rings are preferably corrugated, the meeting faces of the beads having corresponding matching corrugations.
Demas -- No. 1,261,012. Application October 26, 1917, patented April 2, 1918. In a tire casing or shoe there is an 'inflating strip * * * formed of suitably strong and flexible rubber * * * designed to take the place of the ordinary inner tube * * *.'
Saylor -- No. 1,278,224. Application March 6, 1917, patented September 10, 1918. An inflatable vehicle tire not requiring the use of an inner tube, in which the tire is tubular, but split on the inner periphery so it can be opened, closed and resealed, with a liner of soft rubber secured to the canvas and forming a permanent part of the tire.
Holczer -- No. 1,323,457. Application March 8, 1918, patented December 2, 1919. A vehicle wheel tire and rim,
to eliminate the inner tube, between the flanges and beads there being strips of soft, resilient vulcanized rubber 'to insure an air-tight joint.'
Boys -- No. 1,326,437. Application December 23, 1916, patented December 30, 1919. A tire 'lined with a layer of good, air-tight rubber which, in conjunction with the air-tight metal periphery of the felly (rim), serves the purpose of an inner tube.' The rim is grooved, the tire edges having corresponding ribs.
Budd -- No. 1,347,439. Application May 23, 1918, patented July 20, 1920. A tire casing seal in which a one-piece sealing ring of soft rubber is located internally between the beads, the internal air pressure effecting a seal between the outer surfaces of the beads and the rim flanges.
Martin -- No. 1,412,535. Application April 11, 1919, patented April 11, 1922. A pneumatic tubeless tire with thick lining of 'soft rubber compound of good quality, any suitable compound of self-sealing character being employed.'
Johnston -- No. 1,541,508. Application January 16, 1920, patented June 9, 1925. A 'single tube' tire, with a relatively soft rubber lining around the inner wall, which may 'extend along the rim contacting surface (rim base) to the rim flange * * *.'
Linwood -- No. 1,608,703. Application November 4, 1925, patented November 30, 1926. A vehicle tire without an inner tube, with a casing 'provided with a rubber lining integral therewith.' The tread and sidewall stock terminate short of the rim flanges, and the beads, of carcass stock, directly contact the rim flanges.
Mack -- No. 1,653,054. Application February 15, 1926, patented December 20, 1927. The purpose of the patent is to secure an ordinary tire casing upon the rim in such a manner as to form an air-tight closure or seal and to dispense with the ordinary inner tube. Upon the rim between the casing beads is a soft rubber element. Seated upon this element is a high pressure sealing casing from each side of which there extends a flap 'preferably of some soft material, such as an inner tube rubber, which may be integral with' the casing or separate and vulcanized to it, each flap being passed around one of the beads of the tire lining between the bead and the rim, and extending up to and beyond the top of the rim flange. The proposed pressure of 125 pounds would bind the flange against the beads with an air-tight contact and the sides of the tire adjacent the beads would be forced outwardly.
Shoemaker -- No. 1,756,665. Application November 19, 1925, patented April 29, 1930. A semi-tire is shown, one-half the air being retained within a recessed rim. The portions of the tire beads engaging the rim are preferably formed of harder rubber than the remainder of the tire. The rim has edges flanged outwardly inclined in such direction that their planes if projected would intersect within the recessed rim, the incline being such that the air within the tire would force the bead portion outwardly and up the inclines of the rim flanges. The specification asserts that if the tire is greater than a semi-circle,
the bead portions will be forced outwardly and up the inclines and 'will be seated so firmly on the bead receiving portions * * * of the rim that they will form an airtight joint permitting the tire to be used without an inner tube.'
Conigrave -- No. 1,842,315. Application November 27, 1929, patented January 19, 1932. In a 'cavity wheel' device eliminating an inner tube, 'beadings' of a more pliable material or nature than the main body of the 'tyre' extend from the outside across the bead base and up inside the tyre. These beadings act as a seal, packing and wearing agent, and may be made integral with the tyre or be made grooved and attachable thereto.
Daddio -- No. 1,886,470. Application July 16, 1930, patented November 8, 1932. An 'inner tube' is provided, open throughout its length, its edges resting upon a filler which is highly elastic and pliable, the filler member being interposed in the manner of a cushion between the rim and tire beadings. In substance, the filler member is the equivalent of a single chafer strip, not built integrally with the tire or tube, extending from the top of one rim flange to the top of the other rim flange across the base of a flat bottomed rim.
Bull -- No. 1,966,580. Application December 23, 1932, patented July 17, 1934. This patent, assigned to defendant, relates to a method for mounting tires. It is significant because it refers to an abandoned application
for tubeless tires heavily relied upon by defendant as an anticipation, and embodies illustrations of a sealing device in the form of 'rubber gaskets' disposed externally of the bead portions of the tire and cooperating with the flanges of a drop center rim to form a 'fluid tight seal between the tire and rim without the use of a conventional inner tube.'
Daddio -- No. 1,982,135. Application July 5, 1932, patented November 27, 1934. The tire is lined with soft rubber as a sealant and is mounted on a slightly modified drop center rim. When mounted, the beads rest against the bead seats 'with a certain amount of pressure so as to make the chamber which is formed by the shoe (tire) and frame wheel, comparatively air tight.
Shoemaker -- No. 2,186,178. Application February 11, 1937, patented January 9, 1940. The main
bead portions of the tire are supported by the conventional drop center rim. Provision is made for a chafing strip preferably imbedded in the bead portion of the tire so as to extend around each main bead ring just outside the reinforcing layer. The outer end of the chafing strip terminates within the side walls of the tire. As to the sealing of the main beads the patent states, (P. 2, Col. 1, l. 70 and Col. 2, l. 1):
'The tire is completely lined with air tight rubber lining and this rubber extends around onto the base of the bead portions so that when said bead portions are crowded out and caused to bind tightly on the inclined portions 5 of the rim an air seal will be formed and no inner tube will be necessary.'
The bead lock principle and the positioning of the main beads on the rim flange are startlingly similar to those taught by the Harzegh patent.
McMahan -- No. 2,331,795. Application December 18, 1940, patented October 12, 1943. Discussed infra, under Prior Art cited by the Patent Office.
Godsey -- No. 2,410,209. Application September 15, 1941, patented October 29, 1946. Among the objects of the invention are, (Col. 1, ls. 10-23):
'A still further object of this invention is to provide for supplementing the adhesion of the inner strip to the wheel rim by pressure exerted by the tire casing, this constituting a pressure sealing means.'
Reference is made to an inner band preferably of rubber, lining the entire inside of the tire and extending around sufficiently to cover the rim base, and in one illustration to cover the bead flange face.
Young -- No. 2,489,995. Application November 27, 1944, patented November 29, 1949. Described infra, under Prior Art cited by the patent Office.
Plaintiff's Departure from the Patented Liner and its Placement.
(a) Tubeless Tires with puncture sealant
1. Production Period, November 1947 to November 1948.
Plaintiff first offered tubeless tires for public sale on February 2, 1948. These had an unconventional plylock.28A After manufacture of the first 18,000 tires, a change in the plylock was made. The tires, until November 1949, incorporated
the patented claims of a liner of all (new) butyl rubber on the inner surface of the inner ply of the tire, and the inner ply, with the butyl liner coated on its inside surface, extended to the corner of the heel of the bead on each side of the tire. During this period the one-piece sidewall and tread stock extended slightly around the heel of the bead on each side of the tire and lapped the edge of the liner. Beginning in the last months of the period, the one-piece sidewall and tread was trimmed off, during the building operation, at the heel of the bead on each side of tire.
The sealing ribs were formed in the one-piece sidewall and tread, which was made of a natural rubber tread-type stock.
The Herzegh patent recognized the 'natural reluctance' of butyl and other rubbers to adhere, but taught that the inner liner was built into the tire and adhered by its natural tack or with the aid of adhesives, providing a unitary construction on vulcanization. Plaintiff's expert testified that the adhesion was adequate because the air pressure tended to hold the liner against the first ply.
But the poor adhesion of the liner caused considerable trouble. This was reflected in a very large proportion of unsatisfactory tires. The rate of adjustment on conventional tires was in the order of 1% or less; the adjustments on tubeless tires in 1948 amounted to about 23%.
Of these, 9% were due to bead failure, and an unidentified number from ply separation and blisters.
These defects were readily recognized by plaintiff in various memoranda in 1947 (after Herzegh's filing date); and as late as November 11, 1947, the technical head of plaintiff's Tire and Equipment Division said, less than three months before the release of commercial tires:
2. November 1948 to March 1949.
After the manufacture and sale of approximately 70,300 tires of the first construction, a substantial change was made. Plaintiff departed from the unitary liner in which Butyl was the only rubber component, and has never returned to it. In this second period, the liner was constructed of three plies, the center being of all new butyl, and the other two plies of of a blend of replasticized butyl rubber with some natural rubber, giving far superior adhesive qualities than all butyl. The liner was about 50% thicker than the unitary butyl liner of the first period.
A separate piece of liner extended to the corner of the toe of the bead on each side of the tire. An extension, of the two adhesive layers, ran from a point above the bead to a point above the bead heel, being lapped by the sidewall on one side, and by the three-piece liner on the other.
The sealing ribs, as in the first period were formed in the one-piece sidewall and tread, which was made of a natural rubber tread-type stock.
Approximately 11,000 tires were made and sold during this period.
3. February 1949 to October 1952.
In this construction period, the liner was made up of two plies of replasticized vulcanized butyl rubber with some new natural rubber, or both natural rubber and butadiene-styrene synthetic rubber (GR-S). The first or innermost liner ply extended around the heel of the bead on each side of the tire and was lapped by the one-piece sidewall-tread. The second liner ply ended at the corner of the toe of the bead on each side of the tire.
Approximately 1,508,000 tires of this construction were manufactured and sold.
4. October 1952 to September 1953.
GR-S was used for the one-piece side-wall and tread. The sidewall stopped short of the heel of the bead, and a cushion or chafer strip of tread-type natural rubber stock either met or lapped the edge of the sidewall, and extended around the heel of the bead, terminating under the bead base.
During the first few months the two-ply liner corresponded in position, extent and composition with that of the preceding period. Beginning in June 1953, both plies were extended around the heel of the bead, terminating beneath the cushion or chafer strip and the margin of the sidewall.
Commencing in March 1953, the liner composition was modified to include replasticized butyl rubber (40%), new butyl rubber (10%), new natural rubber (20%), and new GR-S (30%), one-half of the rubber content thus consisting of the two butyl ingredients.
The sealing ribs were formed partly in the cushion or chafer strip, and partly in the sidewall material, the chafer strip being of natural rubber and the sidewall of synthetic rubber.
Approximately 740,000 tires of this construction were manufactured and sold.
5. September 1953 to January 1955.
The liner, of the same composition as in period 4 above, of two plies in some instances, extended around the heel of the bead and up the outer face of the bead and was lapped by the sidewall.
6. July 1954 to December 1954.
The two ply liner terminated at the corner of the bead toe and was of the same composition as described in period 4. The one-piece sidewall and tread was made of tread-type natural rubber stock. A fabric finishing strip, coated on the inner surface with liner stock and on the outer face with tread-type natural rubber stock lapped the liner at the inner face of the bead and was in turn lapped by the one-piece sidewall and tread at the outer face. The sealing ribs were formed partly in the natural rubber coating on the finishing strip and partially in the natural rubber of the sidewall, which were of similar character.
Approximately 1,480,000 tires embodying the structures described in periods 5 and 6 above were manufactured and sold.
7. November 1954 to March 1955.
The construction was substantially the same as that described for period 3, except the liner composition was the same as described in periods 5 and 6 above.
Approximately 160,000 tires embodying this construction were made and sold.
The two-ply liner extends just around the corner of the toe of the bead, and is lapped by a finishing strip which is, in turn, lapped at the outer face of the bead by the one-piece sidewall and tread made of tread-type synthetic rubber stock. The finishing strip is coated on its inner surface with liner stock and on its outer surface with a tread-type natural rubber stock.
The sealing ribs are formed partly in the outer coating on the finishing strips and partly in the sidewall, the former being of natural rubber and the latter of synthetic rubber.
Tires of this construction have been and are being made and sold at the rate of approximately 100,000 per month.
All tires produced under the foregoing descriptions contained a crown of puncture sealing material, which extended down only a short distance below the tread. Admittedly, the problems of liner and sealing in the bead areas are identical whether or not a puncture sealant is used.
Tubeless tires without a puncture sealing crown were not produced by plaintiff until 1953. Two different forms of construction for tubeless tires without a puncture sealant have been used, both being in current production. The liner compositions in each are like those used in current production of the puncture-sealant tires, one-half the rubber content consisting of two butyl ingredients, the other one-half consisting of new natural rubber and new GR-S.
(b) Tubeless Tires without puncture sealant
The same two-ply liner is used as in the case of tubeless tires with puncture sealant since February 1949, in some instances the first or innermost liner ply terminating at the heel of the bead, the second liner ply terminating at the toe of the bead. In other instances, both liner plies extend to or around the heel of the bead.
10. January 1955 to date.
Each of the two plies of the liner terminates just beyond the toe of the bead.
The one-piece sidewall and tread is made of tread-type synthetic rubber stock. The sidewall edge laps a fabric finishing strip, which extends around the bead area, and in turn laps the liner plies. The fabric finishing strip is coated on its inner surface with liner stock, and on its outer surface with a tread-type natural rubber stock.
The sealing ribs are formed partly in the outer coating on the finishing strip, and partly in the sidewall, the former being of natural rubber and the latter of synthetic rubber.
Approximately 3,800,000 tubeless tires without sealant were manufactured and sold prior to June 30, 1955. Production is continuing at the rate of approximately 700,000 per month.
All the foregoing descriptions relate to tubeless tires, whether with or without sealant, having black sidewalls. The construction of plaintiff's tubeless tires with white sidewalls is the same, except that in such tires a separate tread-type natural rubber cushion or chafer strip is applied in the bead area of the white wall side of each tire. In the construction where a cushion or chafer strip is not present (Nos. 1, 2, 3 and 5 above), this feature is added on the white wall side of the tire only. This cushion or chafer strip either laps or is lapped by the radially innermost margin of the white sidewall material. The sealing ribs are formed at least in part in the cushion or chafer strip, although some of the ribs may be formed in the white sidewall.
In the first production period, November 1947 to November 1948, in which 70,300 tubeless tires (with sealant crown) were produced, the liner was of butyl rubber, and extended down to the bead portions, around the toe of the bead and to the heel. The patent drawings and this initial production had the butyl liner in engagement with the rim base from the bead toe to or almost to the bead heel. The sealing ribs were of the same material as the sidewalls (of one-piece natural rubber sidewall and tread stock). This left a space between the bead heel and the first rib without the protection of the liner. Thereafter construction was repeatedly changed and the liner was extended around the bead heel and inside the sidewall and/or chafer material, at least to, and in almost all instances well beyond, the first (lowest) sealing rib.
Beginning with October 1952, chafer strips of natural rubber have been used, in which some or all of the sealing ribs are formed. The extent of the chafer has varied from a small strip in the rim flange area to a strip extending from above the beads around the bead heel to, around and above the bead toe. In such cases, which represent current production, the chafer strip is in contact with the metal rim flange and rim base,
and directly in contact with the enclosed air in a portion of the tire above the bead toe.
Under current construction some of the sealing ribs are molded in the synthetic rubber side wall and part in the natural rubber outer portion of the chafer strip.
Defendant's Efforts in the Tubeless Tire Field.
From 1929 to 1939, defendant worked on tubeless tires, including various experimentations, the building of 150 tires, the filing and abandonment of one patent application
and the securing of the Bull patent No. 1,966,580. This involved work both with respect to inner linings and sealing at the rim.
The recognition that the problems in the production of tubeless tires were with relation to a liner less air permeable (or more diffusion resistant) than the balance of the tire, and an effective air seal between the flange face of the bead and the rim flange, is well demonstrated by the memorandum of June 23, 1932 of Dr. Bull (defendant's expert at the trial), in which he said:
'3. An extra coating of rubber must be applied to the band ply and probably to the chafer strip of the tire to provide a section of low air permeability. This is necessary to prevent blistering of the tire due to diffusion of air through the carcass and accumulation under the tread. To avoid blistering it is necessary that the rate of diffusion of air through the band ply shall be slower than through any equal gauge of material in any other portion of the carcass. The use of 'balloon dope' or other solution for reducing the diffusion rate of air through the band ply may be desirable.
'4. It may be necessary to put a sealing strip of rubber around the outside of the bead so an air tight seal can be maintained against the rim flange.'
In the experiments, conventional passenger car tires were coated on the inside of the innermost ply with a rubber coat .020'-.060', or in some instances the coat was placed between two of the carcass plies. The inner surface of such tires was also treated with various substances, including cements.
Approximately 150 tires were built by defendant in its tubeless tire development between October 29, 1929 and November 2, 1939. The results were unsatisfactory from the standpoint of commercial production.
Presumably defendant's work during the period 1929-1939 would not have been contemporaneously available to plaintiff, or the public. However, that part of such work represented by patent application of defendant's employees McNeill and Eger, and a patent granted on July 17, 1934, to defendant's expert Dr. Bull, became part of the public domain on the issuance of the Bull patent. The disclosures in the McNeill and Eger application represent an important port of defendant's defense.
McNeill and Eger abandoned patent application.
On December 17, 1932, after the advent of the drop center rim, George K. McNeill and Ernst Eger, employees of defendant and as assignors of defendant, filed an application for a patent for tubeless tires.
The invention was stated to relate to 'tubeless vehicle tires, and more particularly to tubeless vehicle tires which are used in conjunction with air tight rims * * *. Broadly, the construction is made fluid tight by insuring that the carcass of the tire is fluid tight and by providing special sealing means for co-operation between the bead portions of the tire and the rim.'
A lining is provided to render the carcass 'fluid tight', with 'portions extending around the bead portions * * * of the tire for engagement with the rim seats to insure fluid tight seals between the bead portions and the rim.'
The composition of the liner was described as follows:
'The word 'lining' as used in this specification is intended to cover the use of any
material which may be applied to the interior of a conventional tire for rendering it air tight. It may take the form of a coating of rubber applied to the exposed surface of the inner or band ply of the carcass, or it may take the form of a specially compounded ply of fabric and/or rubber applied beneath the usual inner or band ply of a tire. The material must have the properties of being flexible, fluid tight, and non-cracking in use. It may also be painted or sprayed with a latex or other solution. In any event, the lining used should decrease the permeability or porosity of the inner or band ply of the carcass; also, it must be of a sufficiently soft nature to co-operate with metal to act as a seal.'
Figure 2 and the specifications relate to the addition of one or more ribs 'externally of the bead portions * * * for directly engaging the rim flange to serve as a gasket.'
These ribs were to be of the same material as, and molded integrally with, the liner material.
Provision is also made for a 'gasket or a lining' of 'rubber or other flexible sealing material' inserted in a pocket in, or secured to, the inner surface of the rim flange.
In summary, it is stated that:
'In the several forms of the invention an inner tube is dispensed with by providing that the inner surface of the tire shall be relatively fluid tight, and by providing means for sealing the spaces between the tire beads and the rim so that the inflating pressure within the tire reacts on the bead portions of the tire and against the rim to produce a permanent seal.'
Fifteen claims were filed. The Examiner held that: 'Claims 1, 2, 3, 10 to 15
inclusive are rejected as obviously met by Killen.' The response of the applicant was: 'Cancel Claims 1 to 3, inclusive, and 7 to 15, inclusive.' The remaining claims were amended, and an additional claim, 16, added:
'16. In a tubeless tire, a continuous lining of sealing material secured to the interior of the casing, and extending around the bead portions of the casing and terminating in raised circumferential ribs on the outer face of the casing in position to engage rim flanges to seal the spaces between the bead portions of the casing and said rim flanges.'
This is the only claim referring to ribs. It was rejected by the Examiner for the following reasons:
The remaining claims were amended, with the statement under 'remarks' that:
'All of the claims now in the case cover a tire in which a lining is mounted internally of the casing and extends around the bead portions so as to seal them against rim flanges. Also by having the lining extend around the bead portions, the edges of the fabric at the bead portions are covered and sealed. If the lining is not continuous around the base or bead portions, the air pressure within the casing may work its way up into the carcass between and/or through the plies and will cause either a slow leak or blister on the tread or side wall of the casing. This tendency to leak is increased when the tire is placed in actual service due to the flexing of the casing. Such a condition results in ply separation and premature failing of the tire. By placing the lining of sealing material around the seat of the bead portions such leakage is prevented as well as affording a seal between the casing and its seat on the rim flanges. The prior art cited in the last Office Action does not suggest such a construction, and it is submitted that the claims remaining in the case are allowable.'
However, following the recommendation of April 9, 1934, of defendant's patent department made 'in view of the last Office Action and references cited' by the Patent Office, ...