Independent Pneumatic Tool Co. v. Chicago Pneumatic Tool Co.

N.D. Illinois

Independent Pneumatic Tool Co. v. Chicago Pneumatic Tool Co.

96 F. Supp. 70, 88 U.S.P.Q. (BNA) 527, 1951 U.S. Dist. LEXIS 2401

CourtDistrict Court, N.D. Illinois

DecidedMarch 5, 1951

DocketCiv. A. No. 47 C 855

StatusPublished

Cited by3 cases

This text of 96 F. Supp. 70 (Independent Pneumatic Tool Co. v. Chicago Pneumatic Tool Co.) is published on Counsel Stack Legal Research, covering District Court, N.D. Illinois primary law. Counsel Stack provides free access to over 12 million legal documents including statutes, case law, regulations, and constitutions.

Bluebook

Independent Pneumatic Tool Co. v. Chicago Pneumatic Tool Co., 96 F. Supp. 70, 88 U.S.P.Q. (BNA) 527, 1951 U.S. Dist. LEXIS 2401 (N.D. Ill. 1951).

Pincite

Opinion

HOLLY, District Judge.

Plaintiff’s complaint asks for a declaratory judgment finding that claim 7 of Fitch patent No. 2,219,865 and claims 6, 8, 14, 18 and 30 of Amtsberg patent No. 2,219,883 are invalid and that said claims of the Fitch and Amtsberg patents have not been infringed by plaintiff.

Defendant in its answer and counterclaim averred that it is the owner of the Amtsberg and Fitch patents, that the patents are valid and that plaintiff was engaged in the sale of impact wrenches which infringed the claims of said patents, mentioning particular wrenches known as Thor Models 4, 6, 10, 12 and 20. Plaintiff filed an answer to the counterclaim again charging that the patents were invalid and denying the infringement.

An impact wrench and its method of operation are described as follows in defendant’s brief.

“An impact tool is a device which is used to deliver a series of rotary blows or impacts in seating or releasing a screw, nut or bolt, and is to be distinguished from the ordinary direct drive power tool which applies a smooth torque rather than a rotary blow. The effect produced by the use of an impact tool is similar to that produced when a wrench having been applied to a nut and the nut tightened to the maximum extent possible by rotation of the wrench, the wrench handle is then repeatedly struck with a hammer to produce the final tightening action. * * *

“An impact wrench or tool of any type requires a blow to be delivered, and the part struck has come to be referred to in the art as an anvil, and the part carrying the striking elements as a hammer. The tool, usually either a wrench socket or a screw driver, is connected to the anvil and the motive power to the hammer. The hammer is released from engagement with the anvil between blows, and the mechanism which accomplishes this result is known as the impact clutch. * * *

“The impacting action of the tool does not start until the nut or screw meets considerable resistance. Prior to this time the nut is ‘run up’ on the bolt under the torque exerted by the motor, the hammer being in engagement with the anvil. Upon meeting such resistance the hammer disengages from the anvil, rotates through a predetermined arc, and re-engages, providing a rotary blow which tightens the nut. These rotary blows are delivered in rapid succession until the nut is as tight as desired. In loosening a tight nut of course the impacts occur first and the ‘run-off’ after it is broken loose.”

Before the impact wrench was devised the common method of loosening stay bolts was by means of a wrench with a long handle operated by several men, it being necessary frequently to use a sledge hammer against the wrench handle in order to loosen the stay bolt caps. The average time required for taking down a locomotive boiler by the manual method, says defendant in its brief, was two to three days. With defendant’s impact wrench, operated by one man, the boiler can be taken down, on the average, in two or three hours.

While plaintiff attacks the validity of the Amtsberg and Fitch patents counsel stated during the trial and repeated in their [72]*72reply brief that it relies primarily on the defense of non-infringement. This problem requires us to examine the claims of defendant’s patents alleged to be infringed and the construction and operation of the Thor wrenches manufactured and sold by plaintiff.

First as to the Amtsberg patent. Claims 6, 8, 18 and 30 are as follows:

Claim 6. “In a tool of the character described, a rotatable driven shaft, a rotatable hammer, releasable clutch mechanism interposed between said hammer and shaft, said clutch mechanism comprising striking and stricken impact surfaces arranged to prevent relative rotation between said hammer a nd shaft when said impact surfaces are in engagement and comprising automatic means for disengaging said impact surfaces upon termination of an impact, and a rotary motor for driving said hammer,' said motor having a stator and a rotor and fluid pressure means for driving said rotor, said rotor having a rigid driving connection with the hammer, whereby said rotor and hammer rotate in unison and the angular momentum of the hammer is supplemented by that of the rotor.”

Claim 8. “An impact clutch comprising a hammer rotatable in either direction, a rotatable anvil having a jaw provided with impact receiving surfaces on its opposite sides, a dog pivoted to the hammer and having impacting surfaces on its opposite sides, centrifugal means for moving the dog into the orbital path of the jaw, and automatic means for moving the dog out of the orbital path of the jaw, whereby to cause the dog to deliver a succession of rotary impacts to said anvil jaw, said dog being secured against movement relative to the hammer in the direction of rotation of the hammer.”

Claim 18. “An impact clutch comprising a rotatable hammer, a rotatable anvil having spaced jaws provided with impact receiving surfaces, impact dogs carried by the hammer and movable into the annular path of the jaws in response to centrifugal force to deliver a succession of impacts to said jaws, automatic retracting means operable upon termination of an impact to move the dogs out of the annular path of the anvil jaws, each of said dogs being guided on the hammer for relative movement only in a plane coincident with the axis of rotation of the hammer, whereby the hammer is positively locked against rotation ahead of the jaws.”

Claim 30. “In a device of the character described, the combination of a driving head having rotation imparted thereto in either direction, a rotatable driven head, stationary clutch jaws on said driven head, rotation transmitting clutch jaws pivotally carried by said driving head centrifugally movable, into operative engagement with said stationary jaws irrespective of the direction of rotation of said driving head and capable of release to enable relative rotation between said heads, said clutch jaws arranged and disposed in a manner causing each operative engagement thereof to transmit a rotative impact to said driven head, and means automatically effecting said release upon a predetermined reduction in the rotary speed of said driving head.

The term “means” is indefinite, and when used in a claim must be limited to the means set forth in the specifications or their equivalents. Other means not equivalent are not covered by the patent. Charles Peckat Mfg. Co. v. Jacobs, 7 Cir., 178 F.2d 794. And see Halliburton Oil Well Cementing Co. v. Walker, 329 U.S. 1, 67 S.Ct. 6, 91 L.Ed. 3.

Following is shown a drawing of the Amtsberg device as shown in Figures 1 and 2 of the patent.

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