A.J. Industries, Inc. v. The Dayton Steel Foundry Company

394 F.2d 357, 157 U.S.P.Q. (BNA) 545, 1968 U.S. App. LEXIS 7074
CourtCourt of Appeals for the Sixth Circuit
DecidedMay 6, 1968
Docket17614, 17615
StatusPublished
Cited by19 cases

This text of 394 F.2d 357 (A.J. Industries, Inc. v. The Dayton Steel Foundry Company) is published on Counsel Stack Legal Research, covering Court of Appeals for the Sixth Circuit primary law. Counsel Stack provides free access to over 12 million legal documents including statutes, case law, regulations, and constitutions.

Bluebook
A.J. Industries, Inc. v. The Dayton Steel Foundry Company, 394 F.2d 357, 157 U.S.P.Q. (BNA) 545, 1968 U.S. App. LEXIS 7074 (6th Cir. 1968).

Opinion

JOHN W. PECK, Circuit Judge.

A. J. Industries, Inc. (herein “plaintiff”) brought suit against The Dayton Steel Foundry Company (herein “defendant”) for infringement of Ward Patent No. 2,841,414, which plaintiff *358 owned. Defendant denied infringement in its answer and counter-claimed that the patent in suit was invalid. Only two of the twelve claims to the patent, claims 7 and 8, were tried to the District Court which held the claims valid and not infringed. Both parties have appealed from that decision.

The Ward patent in suit, captioned “Anti-Brake Hop Structure for Wheeled Vehicles,” pertains to a spring suspension system for a vehicle, generally a truck trailer, having tandem axles. More particularly, claims 7 and 8 pertain to a tandem suspension system having the adjacent ends of two elongated springs on each side of the vehicle connected to the frame through an equalizer, the function of which is to distribute loads back and forth between the springs. As stated in the patent specification, the primary improvements contemplated by the invention disclosed are “enhanced braking effectiveness, the elimination of the phenomenon known in the trucking industry as ‘brake hopping,’ and the improvement of the riding characteristics of the trailer, as well as the tractor, during braking operations.” The evidence shows that all three objectives are realized by the elimination of brake hopping.

The phenomenon known as brake hopping was described by Ward in the specification to the patent in suit as follows:

“[Bjrake hop is experienced primarily with unloaded or lightly loaded trailers when a sudden or emergency braking operation is in progress, and the phenomena is characterized primarily by rapid and extremely violent up and down oscillation of either one or both of the axles of the tandem. In what is probably its most common form, this phenomena primarily involves or is exhibited in a readily apparent manner in vibration or oscillation of the front axle, and the vibration is often so great that in each oscillation the wheels of this axle are lifted from the road in an appreciable amount and then returned to road contact with great force or impact.”

As the record shows, it is generally recognized that the extent or intensity of axle oscillation depends on many variables, such as the road surface, the braking intensity and the weight of the trailer.

With respect to the equalized semi-elliptic spring type of suspensions to which the Ward patent pertains, Ward in effect attributed what is known as axle wind-up as the cause of brake hop. His concept of the cause of brake hop may fairly be summarized as follows: when the wheels are locked to the tandem axles during braking, the tire-to-ground friction tends to rotate the axles in a forward rotational direction. The springs of the suspension, one of which is attached to and support each end of the axles, are caused to cant in such a manner that the rear end of the springs attached to the front axle move upwardly and the front end of the springs attached to the rear axle move downwardly. This spring movement is not impeded by the equalizer and the net effect is that the front axle tends to be lifted from the pavement. Thereafter because the weight of the rear portion of the trailer is shifted, or tends to shift, to the rear axle, and because of the reduction or total elimination of friction between the tires attached to the front axle and the pavement, the front wheels tend to return to their normal, load-bearing position in contact with the roadway, whereupon the cycle starts over again. It is the rapid repetition of this cycle that creates the brake hop.

In the prior art devices disclosed in the patent in suit, the tandem axles are pulled along with the trailer by torque rods attached to the axles through forwardly extending arms secured to each end of the axles. In these prior art structures, the rear end of each torque rod is attached to an arm at a point forwardly and slightly above the center-line, or axis, of the related axle, the front end of the torque rod being attached to the frame through brackets forwardly of the related axle. Ward’s invention consisted of the placement of these torque rods “in a dif *359 ferent and highly advantageous relationship between the frame and the respective axles.” As stated in plaintiff’s brief, “Ward contrapositioned the connection for the rear of the torque rods from a position above the axle to a position below the axle. This change was Ward’s invention.” It is claimed that by changing the position of the rear end of the torque rods as Ward did, the forward inertia force of the vehicle is harnessed as a counterrotative force on the axles, thus precluding brake hop. A drawing accompanying the Ward patent and depicting an embodiment of the claimed invention is set forth below:

July 1, 1958 J. C. WARD 2,841,414
ANTI-BRAKE-HOP STRUCTURES FOR WHEELED VEHICLES
Filed March 2, 1954 3 Sheets-Sheet 3

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Bluebook (online)
394 F.2d 357, 157 U.S.P.Q. (BNA) 545, 1968 U.S. App. LEXIS 7074, Counsel Stack Legal Research, https://law.counselstack.com/opinion/aj-industries-inc-v-the-dayton-steel-foundry-company-ca6-1968.