Grover Loening Aircraft Co. v. United Aircraft Mfg. Corp.

28 F. Supp. 93, 42 U.S.P.Q. (BNA) 109, 1939 U.S. Dist. LEXIS 2507
CourtDistrict Court, D. Delaware
DecidedJune 16, 1939
DocketNo. 1188
StatusPublished

This text of 28 F. Supp. 93 (Grover Loening Aircraft Co. v. United Aircraft Mfg. Corp.) is published on Counsel Stack Legal Research, covering District Court, D. Delaware primary law. Counsel Stack provides free access to over 12 million legal documents including statutes, case law, regulations, and constitutions.

Bluebook
Grover Loening Aircraft Co. v. United Aircraft Mfg. Corp., 28 F. Supp. 93, 42 U.S.P.Q. (BNA) 109, 1939 U.S. Dist. LEXIS 2507 (D. Del. 1939).

Opinion

NIELDS, District Judge.

This is a patent suit charging infringement of Patent No. 1,759,652 granted to Grover Loening May 20, 1930, for “Retractable Landing Gear”. The claims in suit are 1, 2, 3, 5, 7, 9 and 11. The structure charged to infringe is the landing gear of Sikorsky, Model “S-43” amphibian airplane.

The defenses are invalidity, noninfringement and failure to comply with U.S. R.S. § 4888, 35 U.S.C.A. § 33.

The Patent

The patent in suit relates to the use of a few simple elements for lifting the wheels of an airplane while in flight. They are: (1) A folding strut with a toggle joint which is folded in lifting the wheels. (2) An offset hinge for the toggle joint such as is used on doors. (3) A “push and pull” [94]*94rod for operating the toggle struts. (4) A shock absorber in the lower member of each strut. (5) Means to lock the toggle struts when protracted.

Plaintiff frankly states that the invention is not the discovery of a new element or part. But, says plaintiff’s attorney, “it was a new arrangement of the parts upon which a new structural law was imposed”. Plaintiff’s position was more coherently stated when he admitted an offset hinge was not novel “but it is novel in a landing gear”. This opinion deals with the merit of that statement.

At the trial plaintiff relied principally upon Fig. 9 of the patent:

May 20, 1930. G. LOENING 1,759,652 RETRACTABLE LANDING GEAR FILED JUNE 29, 1929 5 SHEETS-SHEET 5

In this figure the landing gear of the patent comprises two foldover struts having toggle joints with offset hinges. The upper and lower members of the toggle struts are 13b and 12b. The figure shows wheels 7 and associate landing gear on each side of the amphibian. Shock absorbers 14 and 15 composed of rubber disks and washers are in the lower half of each toggle strut. There is also a rubber band 33 which is intended to prevent accidental openings of the joints. By means of rod 30b the pilot can pull up or push down rods 51 which open or close the hinges. The wheels swing up and down on the radius rods 50 attached to the hull of the airplane. Fig. 9 represents an amphibian but the patent states that the invention relates to “airplanes, more particularly seaplanes, flying-boats and the like.” The patent in suit had nothing to do with originating or developing the amphibian type of airplane. Such airplanes were in commercial use long prior to the patent in suit.

[95]*95In its brief plaintiff states “the arrangement of Fig. 9 of the patent is particularly pertinent here for it is that structure which defendants have adopted”.

In the specification the patentee says:

“Fig. 9 illustrates the application of the invention to a two-wheel landing gear of the kind in which the wheels are disposed outside of the float or floats and are connected therewith by laterally swinging links. In this case the axles of the wheels are on the lower ends of toggle members 12b, which have shock absorbers built into them in the manner which has been described. These members are connected with the opposite sides of the float 2 by links 50, which guide the wheel-carrying members in the protracting and retracting operations, and take lateral and rearwardly acting stresses on landing, thus performing the general functions of the rectilinear guides of the other forms of the invention.
“The upper toggle members 13b are connected to the lower toggle members 12b by the same form of offset hinge with abutments, as in the case of the members 12 and 13 first described, only in this instance the hinge pintle is offset outward from the line of thrust through the main strength strut. The members 13b are pivotally connected with the body 3, the axes about which these joints flex being fore and aft instead of transverse. Pivotal links 51 connect the members 13b with a push and pull rod 30b”.

The operation of the device is as simple as its elements. If the wheels 7 are down and the pilot wants to pull them up after taking off, he pulls up rod 30b which in turn pulls on rods 51 and opens the toggle hinges on each side. The wheels 7 swing upwardly around their links 50 into the position shown by the dotted lines. When the pilot wants to land he pushes down on rod 30b. That pushes down rods 51 and lowers the wheels by straightening the toggle struts.

Loening, the patentee, was president of the plaintiff corporation. In the early days of the aeroplane industry he had played a prominent part. At the hearing he testified as expert on behalf of plaintiff and placed much emphasis upon the offset hinges although when the patent was applied for the hinges were not numbered or identified in Fig. 9. The offset hinges are simply the joints between the two parts of the folding toggle struts. It is assented by the plaintiff that they produce “a self locking effect” when the weight of the airplane is placed upon the struts in their straightened position. The weight of the airplane when resting on the wheels is taken by the abutting faces of the hinge instead of by the hinge pin.

Claim 5 is selected by plaintiff as typical. It reads: “5. In an airplane, a retractable landing gear comprising a wheel-carrying part, means for guiding the same, a foldable main strength strut comprising a toggle having its upper member connected with the fixed structure of the airplane and its lower member connected with said wheel-carrying part, an offset hinge device connecting the toggle members whereby the toggle is self-locking when straightened, and means for folding and straightening said toggle.”

The elements of this claim are — a retractable landing gear having a wheel and axle, guiding means like the links 50 for the wheel and folding toggle between the airplane and wheel, an offset hinge used as the hinge of the toggle, and a “push and pull rod”, or any other device for opening and closing the hinge.

The principal parts of the mechanism are very old. They are substantially those of a man’s leg. The operation is similar to standing and walking. The language of claim 5 beginning with “a foldable main strength strut” in the third line of the claim to the end of the claim, is applicable to the human leg if the human body and foot is substituted for the fixed structure of the airplane and for the landing gear or “wheel carrying part”. Other claims, e. g. 11, incorporate the shock absorber in the lower member of the toggle strut corresponding to the arch of the foot or to a rubber heel.

Prior Art

The prior art shows the mechanism of the patent applied to retractable landing gear for airplanes. Such airplanes operate ■ in the same way as the patent to produce the same result. As early as 1870 the use of the toggle joint, like 13b and 12b of Fig. 9 of the patent was described in a well known mechanical handbook “507 Mechanical Movements”. The book describes the operation of the toggle by a push and pull rod like 51 of the Loening patent. Since 1909 shock absorbing means have been incorporated in the lower parts of airplane landing gear. The Wrights used a rubber tire for the purpose. The offset [96]*96hinge is an ancient mechanical device, for example, a door hinge. It was applied to folding struts in airplane retractable landing gears long before Loening’s patent. McCarroll Patent

In 1918 McCarroll filed an application for a patent for “Folding Landing Gear For Aircraft”. In 1920 his patent No. 1,329,533 was granted. See Figs. 1 and 3:

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28 F. Supp. 93, 42 U.S.P.Q. (BNA) 109, 1939 U.S. Dist. LEXIS 2507, Counsel Stack Legal Research, https://law.counselstack.com/opinion/grover-loening-aircraft-co-v-united-aircraft-mfg-corp-ded-1939.