Comptograph Co. v. Mechanical Accountant Co.

140 F. 136, 1905 U.S. App. LEXIS 4773

This text of 140 F. 136 (Comptograph Co. v. Mechanical Accountant Co.) is published on Counsel Stack Legal Research, covering U.S. Circuit Court for the District of Rhode Island primary law. Counsel Stack provides free access to over 12 million legal documents including statutes, case law, regulations, and constitutions.

Bluebook
Comptograph Co. v. Mechanical Accountant Co., 140 F. 136, 1905 U.S. App. LEXIS 4773 (circtdri 1905).

Opinion

BROWN, District Judge.

Fetters patent No. 465,255, to D. E. Felt, dated September 15, 1891, are for improvements applicable to recording computing machines, and contain some claims applicable alike to calculating machines which print the result and to machines which do not print, but simply show the result on numeral wheels. The present controversy is now limited to claims 7 and 8, which relate solely to “subtraction cut-offs,” or devices whereby the operator may throw out of operation any one of the carrying mechanisms.

The opinion denying a preliminary injunction is reported in (C. C.) 129 Fed. 394, and it may be useful to refer thereto for explanation of matters dealt with in this opinion. The claims are:

“(7) The combination with numeral wheels, actuating devices therefor, carrying-pawls, and devices for actuating said carrying-pawls to carry the tens, of a device for preventing the operation of the carrying-pawls, whereby the operation of subtraction is accomplished, substantially as specified.
“(8) The combination with numeral wheels, 4, actuating mechanism therefor, and carrying-pawls, 27, of levers, 44, having arms, 46, substantially as and for the purpose specified.”

The important feature of the combination claimed is “a device for preventing the operation of the carrying-pawls,” “levers, 44, having arms, 46.” These will be referred to as “subtraction cut-offs.” Subtraction is performed on certain calculating machines by the addition of complementary numbers. This is because it is undesirable' to reverse the'movement of the numeral wheels. In “additive subtraction,” as it is called, the wheels move as in addition. For example, 6 — -3=3. The same result follows if we add the complement of 3, namely, 7, to 6=13, and mentally disregard or cross off the 1 in the tens column. This is an application of a familiar arithmetical principle. A complement of a number is the difference between thát number and a higher power of 10; for example, the complements of 25 are 75 (100 — 25), 975 (1000 — 25), 9975 (10000— 25), etc. As the arithmetical process of “additive subtraction” is in fact addition of a complementary number, it will, when completely carried out, either with pencil and paper or upon a calculating machine, give a result which, as recorded, is erroneous, the error being a “1” on the left, which must either be disregarded or [137]*137struck out in order to give the correct result. The error may be avoided by omitting to carry the last “1” on the left.

The specification states:

“Another object of my invention is to prevent the carrying of tens from any column to the next higher whenever a subtraction is to be made by means of adding a complementary number. * * *”

This is done by “subtraction cut-offs,” so called — a series of levers each having a finger piece and an arm to lift a carrying-pawl. Any carrier may at will be thrown out of operation so that it will not move the wheel to the left. It was old to perform additive subtraction on a calculating machine, and to correct the error by mentally disregarding it, or by removing the “1” by adding a 9 to that wheel and all other numeral wheels at the left, a proceeding known as “running off the pines,” or, as suggested by Grant, by turning the wheel back one tooth by hand. The error was well known. It was an incident of the arithmetical principle,-and was not an error in the operation of the mechanism. The error in the result, however, involved the trouble of removing it by striking the nines. Felt devised the “subtraction cut-offs” to obviate the necessity of striking the nines to remove the undesired “1.” Instead of allowing the error to occur and then curing it, he provided means to prevent its occurrence. While, so far as appears, Felt was the first to prevent the ocurrence of the error by stopping the carrier which caused it, it hardly can be held that the claims are to be construed as broad claims for all means for the prevention of this error. The scope of the invention claimed is a narrow one. In any single problem in additive subtraction done on a calculating machine there was an error caused by the left-hand carrier. This was well known, and was provided for in one way. Felt provided for it in another way. At most, he is entitled to patent the means he devised for stopping a carrier, if the means involved invention. He cannot monopolize the principle that prevention is better than cure as applied to calculating machines. The means provided by Felt is a lever having a finger piece projecting on the outside of the machine, and an arm which engages and throws out the carrying-pawl. A single lever is all that is needed in any single problem in subtraction. As a calculating machine must be able to do a variety of sums, and as the subtrahends will contain a varying number of numerals or places, it is apparent that the location of the false carry will vary as the number of places in the sums varies. Therefore the means for correcting the error must correspond with the character of the sums to-be performed. Felt therefore provided a number of subtraction cut-offs — one for each carrier — for the simple reason that the sums to be performed varied, and not because several were necessary in doing a sum in additive subtraction. In doing a sum in subtraction, only one of the cut-offs is used, and, so far as the performance of that problem is concerned, all the other cut-offs might be removed from the machine.

Complainant’s counsel say that “the mechanical performance of additive subtraction is greatly facilitated and rendered mechanically [138]*138complete by providing means for selectively throwing out of operation any one of the several carrying mechanisms,” etc. .This statement must be carefully scrutinized. The mechanical performance of additive subtraction requires only a single cut-off to correct a single carry. In any particular mechanical performance of additive subtraction the combination of operative parts would include only a single lever. It is doubtless a convenience to have a multiplicity of cut-offs, but a single cut-off is all that can be used in additive subtraction. A particular cut-off is selected by the operator, according to the sums he has to do, exactly as particular keys are selected to put on a given sum for addition. If, as complainant says, the invention is broadly mechanism whereby additive subtraction may be performed without requiring any correction of the remainder, all levers may be disregarded save the one in operation. If the machine were always operated to do the“same sum in subtraction, one cut-off would be enough. It is apparent, therefore, that these cut-offs have no mysterious relation to any arithmetical process, but that one acts separately to prevent the final carry in any sum in additive subtraction. It is claimed that “the invention is, broadly, mechanism whereby additive subtraction may be performed without requiring any correction of the remainders,” and that both the result and the means employed are broadly new with the patentee Felt. If the test of infringement is the performance of the function of preventing the final carry in additive subtraction, the defendant doubtless infringes. But this cannot be the test. It is open to all makers of calculating machines to use any arithmetical principle and to make mechanism operating on that principle. To omit the final carry in doing additive subtraction would be obvious to any mathematician who knew that if he wrote down the final carry he would have to cross it out again to arrive at the correct result.

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Bluebook (online)
140 F. 136, 1905 U.S. App. LEXIS 4773, Counsel Stack Legal Research, https://law.counselstack.com/opinion/comptograph-co-v-mechanical-accountant-co-circtdri-1905.