These cases involve the validity, and the alleged infringement, of letters patent No. 1,127,660, of date February 9, 1915, issued to John H. McMichael, and assigned to Concrete Mixing & Conveying Company.
The Court of Appeals of the Second Circuit, in Concrete Mixing & Conveying Company v. Ulen Contracting Corporation, 12 F.(2d) 929, held the patent valid and infringed. In No. 3 the District Court followed that decision. Its decree was affirmed by the Circuit Court of Appeals of the Second Circuit. 27 F.(2d) 668.
Meantime, in No. 4, the District Court for the Western District of Washington held the patent void for want of novelty and invention. 23 F.(2d) 131. Subsequent to the decision of the Court of Appeals of the Second Circuit, that of the Ninth Circuit affirmed the Washington District Court. 27 F.(2d) 838. In view of the conflict thus disclosed, this court granted certiorari in both cases, 'the two cases to be heard as one.' 278 U.S. 595, 49 S.C.t. 95, 96, 73 L. Ed. 526.
The patent is for certain new and useful improvements in methods of and apparatus for transporting and treating concrete. The accompanying drawing illustrates the apparatus.
[NOTE: MATERIAL SET AT THIS POINT IS NOT DISPLAYABLE (GRAPHIC OR TABULAR MATERIAL)]
It consists of a chamber 1, for the reception of the material, the lower portion being hopperlike in form, as indicated at 2. The cover 4 is provided with an opening 3, in which there is a door 5. A chain or rope 3a is adapted to be used in partly or entirely closing the door. Air pressure in the chamber also acts to hold this door in closed position. A pressure tank 6 holds compressed air supplied by an air compressor 7, and has a connection 8 leading the air under pressure from the tank to the chamber 1; the air inlet is preferably near the top. An air pipe 10 controlled by a valve 11 also leads into the chamber; the delivery end of this pipe being at or near the discharge or lower end of the hopper.
The apparatus includes a valve-controlled water supply pipe 12 adapted to deliver water at the lower end of the hopper so as to make the mass more easily movable when desired, and also a crook or U-shaped bend 14 in the discharge duct 13.
The operation as described in the application for patent consists in depositing material in the chamber, closing the door, turning the air from the reservoir through the pipe 8 into the upper portion of the chamber, thus insuring the immediate firm closure of the door and forcing the material in the hopper downward; it being carried along through the conveying tube 13 until it is finally discharged at 15.
In the application as originally filed it was stated that, owing to the provision of the U-shaped bend in the conveying tube, the material, immediately after leaving the hopper, will be more or less tightly packed; and it is added that 'to loosen the material at the lower end of the hopper should the same become packed, I provide the additional air pipe adapted to discharge air through the material.'
It should also be remarked that in the original application the invention was described as useful improvements in apparatus for 'elevating and transporting granular and plastic building material, such as sand, plaster, mortar and concrete.'
The application was filed in the Patent Office on January 14, 1907. Its prosecution was most dilatory. Claims made were repeatedly disallowed, and at one time it lapsed and had to be renewed. Radical changes were mae i n the statement of invention, and radically new claims were made in 1911 and expanded in 1913. The applicant eliminated from the scope of his invention the transportation of granular and plastic material generally, and limited it to the transportation and treatment of concrete; and the patent as issued is so limited. While his original assertion that the compressed air admitted to the chamber behind the mass was the propelling force was retained, statements were added and claims were made, ascribing to the air discharged by pipe 10 new action and effect, namely, that it operated to 'engage submasses' or to 'impinge upon successive portions' of the mass of concrete moving through the hopper and discharge duct, and to aid or assist in their movement in the duct, as well as assisting in mixing and mingling the elements of the concrete in the duct, so as to make a more perfect mixture.