Independent Pneumatic T. Co. v. Chicago Pneumatic T. Co.

• Citation: 194 F.2d 945
• Decision Date: 04 March 1952
• Docket Number: 10409.,No. 10408,10408
• Parties: INDEPENDENT PNEUMATIC TOOL CO. v. CHICAGO PNEUMATIC TOOL CO.
• Court: United States Courts of Appeals. United States Court of Appeals (7th Circuit)

194 F.2d 945 (1952)

INDEPENDENT PNEUMATIC TOOL CO. v. CHICAGO PNEUMATIC TOOL CO.

Nos. 10408, 10409.

United States Court of Appeals Seventh Circuit.

March 4, 1952.

Floyd H. Crews, New York City, William E. Lucas and Loftus, Lucas & Hammand, all of Chicago, Ill. (Darby & Darby, Donald J. Overocker, and Raymond G. Mullee, all of New York City, of counsel), for Chicago Pneumatic Tool Co.

Harry W. Lindsey, Jr., George N. Hibben, Chicago, Ill., for Independent Pneumatic Tool Co.

Before KERNER, LINDLEY, and SWAIM, Circuit Judges.

KERNER, Circuit Judge.

This was a complaint in which plaintiff Independent Pneumatic Tool Company prayed that the court enter a declaratory judgment that defendant's Amtsberg patent 2219883, issued October 29, 1940, on an application filed June 5, 1937, and Fitch patent 2219865, issued October 29, 1940, on an application filed October 14, 1938, were invalid, and that plaintiff's "Thor Wrench" was not an infringement of either of these patents. The defendant Chicago Pneumatic Tool Company filed a counterclaim in which it asserted that its patents were valid and that plaintiff's wrenches infringed claims 6, 8, 18 and 30 of the Amtsberg patent and claim 7 of the Fitch patent. The trial judge found that neither of defendant's patents disclosed any novel feature; that both Amtsberg and Fitch used old elements in the construction of their wrenches and for patentability depended upon a new combination of old elements, and that while both plaintiff's and defendant's wrenches had many features in common, yet there were important differences. He held that the two patents were valid but not infringed, 96 F.Supp. 70, and both parties have appealed.

The record discloses that the oral testimony covered every factual element relative to the issues. During the trial colored charts were explained in detail, cut-away and disassembled models of wrenches were manually demonstrated, and high speed movies and still enlargements of these movies illustrating the operation of the various parts of the wrenches were shown.

The patents are for improvements in impact tools having particular application to impact wrenches for tightening and loosening nuts and bolts by a rotational hammer action, and the principal issue is infringement. The patents and the claims in issue are correctly described in the District Court's opinion, and since a general description of impact tools also appears in the opinion we shall not repeat it here.

Impact tools are not new. Rotary impact wrenches and impact wrenches utilizing centrifugal means were in existence and were used as far back as 1928, as is evident from Niedhammer's patent, issued on January 24, 1928. It disclosed a tool adapted for tightening or loosening nuts by impacting a series of hammer blows in a rotary direction against an anvil secured over a nut, the tool being torque responsive and declutched by a camming action. A spring is used instead of centrifugal force to urge the impact. A British patent, accepted in December, 1930, made known that centrifugally operable impact dogs on a rotatable hammer could be utilized in a rotary impact tool. The impact elements are clutched by centrifugal force and declutched by a camming action.

In 1934 a torque-responsive wrench was commercially sold by Ingersoll-Rand, and in 1936 defendant manufactured and sold a wrench embodying a torque-responsive declutching means in the form of a separate cam. Prior to Amtsberg, Fitch, not to be confused with the Fitch patent in suit, designed a wrench, its hammer being driven by a cam which served as a non-rigid and non-integral drive means and as an automatic declutching means.

As we have observed, the question is whether plaintiff is guilty of infringement. Because we believe the claims in suit are valid, we shall discuss only the issue of infringement.

In its brief defendant says that the distinguishing features of the Amtsberg structure are that the motor and hammer come to a complete stop upon the delivery of the blow to the anvil jaws. The striking elements, having stopped, are not subject to any centrifugal force and are returned to their position of rest, i. e., disengaged position, by spring pressure, and due to this arrangement no portion of the power of the motor is utilized in moving the striking elements from the path of the anvil jaws. It also states that Amtsberg provides a flat, full contact surface between the striking element and the anvil jaws so that the blow is delivered without any camming action, or inclined surface, to soften the blow. Amtsberg's disengagement, it is claimed, is effected by light springs which become effective only after the centrifugal force on the striking elements or dogs is reduced to zero.

Amtsberg's drawings show an air motor at the right hand side and a hammer near the left hand side of the structure, the hammer being integrally formed as the lower end of a rotating...