The opinion of the court was delivered by: BYERS
These patents deal with a speed governing device installed in the conduit between the carburetor and the engine, of automobiles, buses, tractors, etc.
The intake stroke of the piston in the interior combustion gas engine cylinder creates suction in the manifold above the carburetor; into that conduit there is introduced a value or gate, which is held in place by a shaft the ends of which are so engaged at the interior of the conduit that the valve can rotate about its axis; by reason of the higher degree of vacuum above the valve (toward the engine) than below, the valve tends to move across the conduit toward a closing position, and thus to reduce the flow of fuel from the carburetor to the engine. If the closure were complete, the fuel supply would be cut off, instead of being controlled.
Since the valve is designed as a speed control agent, it is necessary to prevent full closure. The problem is complicated by the additional fact that the closing tendency is not constant, but increases during the movement from the fully opened to the fully closed position, so that, since it is desired to maintain the valve in position between these two extremes, it is requisite to provide a countervailing force which will resist the closing tendency; that force must vary in intensity according to the demands made upon it.
A secondary impulse causing the valve to close, is the impact of the flow of fuel against the Lower side of the valve or gate.
The practice has been employed in the plaintiff's devices under examination, of placing the axis off center, whereby one wing or section of the valve is larger than the other, and of necessity the mounting of the shaft in the conduit is also off center. Thus the valve is subject to two forces which tend to close it; the reduced pressure above it, and the fuel impact from below, which is unevenly distributed across the surface of the valve.
The evidence has covered a wide field, but it is necessary to center attention upon the problem of providing the variable offsetting force to oppose the closing tendency of the valve, so that the latter may be held within a desirable range of response to a predetermined speed (revolutions per minute), in order to ascertain whether the plaintiff's solution of the problem constitutes patentable invention; and whether the defendant's device is the same thing mechanically as the plaintiff's.
The limit of speed having been determined, the governing action consists in accommodating the fuel supply to the varying requirements of road conditions, such as change of grade and wind resistance. In other words, more power is required to move a given truck up-hill than on a level stretch of road, and the governor must admit of a change in the fuel supply up to the desired limit of speed, so that the requisite power may always be maintained.
The ideal result would indicate precision of governance, but practically that is not desired, for there must be a margin of tolerance or failure to govern, of from 10% to 15%, to meet road, traffic, and other operating conditions.
The governing device, as so designed, was operative so long as it was accepted by the drivers of buses and trucks as a desirable part of equipment; they discovered, however, that its function could be frustrated by disabling it through manipulation of the antecedent manually operated throttle valve. The latter is also a disc or gate, between the carburetor and the governor valve, the office of which is to control the volume of fuel emerging from the carburetor and presenting itself to the governor valve.
Under normal operation of the governor valve, the throttle valve is wide open; that is, it is parallel to the walls of the conduit. In that position, the flow of fuel is unimpeded and the pressure is substantially that of the atmosphere, in the region below the governor valve. If the throttle valve is partially closed, however, the drop in the volume of the flow of fuel (and change in its velocity?) thereby induced, tends to increase the vacuum, or to decrease the pressure below the governor valve, so that the functioning of the latter, i.e., the maintenance of its balance, is thereby disturbed, and it fails, or tends to fail, to govern the operations of the engine so that a predetermined speed may not be exceeded.
In order to restore the conditions so disturbed, an element had to be supplied which would tend to move the governor valve as though the pressure below it had not been changed. That agency was added in the form of a piston moving laterally against the governor valve, which was actuated by atmospheric pressure. Thus the nearly atmospheric pressure formerly existing directly below the governor valve, though absent because of the change in position of the throttle valve, was in effect reinstated through the action of the piston which was exterior to the conduit. This is known as the "anti-steal" or the "throttle steal" element.
The foregoing is thought to portray, in plain language, the bare outline of the territory in which this controversy has been conducted.
The plaintiff's cause is based upon three patents: Hufford No. 1,537,944, Handy No. 1,584,929, and Bull No. 2,048,423.
The defendant's unpatented device is said to infringe upon them, and the pathway to adjudication is thought to lie through the wavering precincts of earlier appropriation, because not otherwise can the competing structures be understandingly compared.
The Handy patent (filed May 21, 1920, granted May 18, 1926) is for such a governor as has been discussed; i.e., a single unbalanced butterfly valve the closing effort of which is accelerated through the difference in pressures above and below; the effort is "substantially balanced at all operating at a constant predetermined speed, and * * * said effort is over or under-balanced at other speeds."
The disclosure presently important is of a linkage between the valve and a spring which opposes the former's closing effort, so designed that the energy of the spring, which would otherwise be expended in a constant or linear aspect, is actually rendered variable effective in response to the changing demands made upon it, by the variable turning effort or torque of the valve.
The Hufford patent (filed August 22, 1923, granted May 19, 1925) is said to deal with a flow responsive valve, which manifestly is not of the type here involved. The complex mechanical arrangement of the valve itself does not require exposition. The important feature of the patent is the throttle steal device which it was the first to teach; its place in the plaintiff's case is to justify the presence of the latter's throttle steal assembly, and its adaptation to the combination shown in the third patent.
The Bull patent (filed June 8, 1929, granted July 21, 1936) is described as being for a "stabilizer for suction governors." It is in effect a combination of the structures of the first two patents; that is, the valve is of the butterfly type, with yielding means to offset its closing effort, and the throttle steal piston in mechanical association. The latter is said to augment the closing effort of the valve, to prevent fluttering of the valve, and to prevent stealing.
The discussion as to validity will be largely confined to the Handy patent, because the Hufford and Bull teachings are subordinate to it.
Handy No. 1,584,929: The claims in suit are 3 and 16, as follows:
"3. A governing device comprising in combination, a conduit, a valve in said conduit adapted to be actuated in the closing direction in accordance with the flow of fluid in the conduit, a spring, and means transmitting the force of said spring to oppose the closing movement of said valve, said means constructed and arranged to increase the effort exerted on the valve by the spring as the valve is moved in the closing direction to such an extent as to balance the closing effort on the valve in all positions thereof when the motor is running at a predetermined speed."
"16. A governing device for hydrocarbon motors comprising an intake conduit, an unbalanced butterfly valve therein, and a counterbalancing means connected to balance the turning effort of said valve at a predetermined speed of the motor including an arm secured to turn with said valve, yielding means acting on siad arm having its point of action shifted radially as the arm turns to increase the effort of the yielding means on the valve as it closes."
The patentee states that the vacuum above the governor increases at an accelerated rate when the motor operates at a constant speed, which means that the closing effort of the valve similarly responds thereto, and that a spring which opposes that movement ordinarily offers a "gradually increasing resistance" which cannot offset the acceleration so described.
To enable such a spring to meet the kind of demand to which it is supposed to respond, a method of connecting the spring to the governor had been devised, whereby the resisting capacity of the spring could be employed in correspondence to that closing effort, namely: A cam was attached to the spring and another to the valve, and they are in contact; as the valve moves to a closing position, its cam moves clockwise; opposing it is the spring cam and the point of contact between them is the point at which the energy of the spring opposes the closing movement of the valve; it is a moving point, since the second cam also moves clockwise, and the point of contact changes as the cams move, and on obedience to the force exerted by the valve in its turning effort. As has been shown, that force is a variable, so that the resistance of the spring directly responds to the variability of the closing force or movement of the valve to which it is opposed.
In two respects therefore the plaintiff asserts that the patent taught something not previously disclosed in the art, namely, the variable closing tendency of the valve, and the means to oppose that tendency by a resistance which would variably correspond, in order that at any given position of the valve there would be opposed to it an arresting force which would hold it substantially in that position.
Reliance, to establish anticipation, is had upon: Benjamin No. 1,212,177 (application filed January 11, 1915, granted January 16, 1917); Stoeffel No. 1,230,337 (application filed August 17, 1916, granted June 19, 1917); Jennings No. 1,379,186 (appication filed February 24, 1920, granted May 24, 1921); Pierce No. 1,461,993 (application filed October 31, 1919, granted July 17, 1923); Tondeur No. 277,156 (Belgian; application filed October 18, 1917), and Saxby (British) No. 3,326 of 1875. These citations are really directed to the Handy patent.
So far as Benjamin is concerned, the specifications and claims will be searched in vain for evidence that he was aware of the variable closing effort of his valve, i.e., torque, and the required variable offset to that, to be derived from his spring. His device was never manufactured and at best it must be classed as a paper patent the teachings of which are entirely theoretical. To meet that obvious situation, the defendant constructed, with partial fidelity to the drawings, two models which are assumed to embody substantially the first alternative structure described by Benjamin.
The extent to which they functioned when tested on the road is intersting, but of little value in assigning a definite status in the art to the Benjamin patent. That they could operate, one with an on center and the other with an off center valve, to somewhat restrict the fuel supply, may be granted for present purposes.
It is not the fact of operability but the nature and extent of disclosure which is of present import.
Benjamin's governor for gas engines employs a butterfly valve, but he does not say that it is unbalanced. I should suppose that the trifling difference in the dimensions of the two blades or sides, as shown by the drawing, is probably due to the draftsman's indication of perspective in showing the valve, its suspension, and linkage through a short pinioned arm to a rod connected with a piston which operates in a cylinder exterior to the conduit.
That piston moves laterally in response (a) to the variation between atmospheric pressure acting on its upper surface, and the pressure existing in the manifold adjacent to the valve, which is communicated through a passage opening into the cylinder wall, under the piston; and (b) to the force exerted against its under side by a spiral spring the base of which rests upon the base of the cylinder in which the piston moves. That base is penetrated by the piston rod which is coupled to the valve of the governor.
Benjamin explains the operation of the device as depending upon manifold suction (pressure) change which is communicated to the exterior cylinder and causes the piston to move: "This decrease of suction in the chamber 20 (the cylinder) will permit spring 24a to move the piston 19 to the right as shown in Fig. 1, until the lessening tension of the spring is just balanced by the suction on the piston 21." That language is unfortunate because there is but one piston numbered 19. Probably the word "at" should precede the number 21. The meaning is that the piston moves in response to change of pressure in the manifold, which affects the action of the spring to which the valve is coupled as explained.
The claims 1 to 7, inclusive, seem to be consistent with the foregoing, and to involve additionally "manually controlled pneumatic means for controlling said governing means."
The control so described in claim 1, and less specifically in the others, refers to the passage leading from the manifold to the piston chamber, which is controlled in turn by another passage which "bleeds air," as the witness Bull expressed it, into the first mentioned passage; the latter is the agency for communicating the manifold pressure to the piston chamber. Therefore, since the fidelity of piston performance is subject to manipulation by the admission of atmospheric pressure, apparently the patent teaches a control of the governor valve solely through response to the exterior piston action, which may be in part at least responsive to manual actuation.
That does not deal with the subjectmatter, nor is it an anticipation of Handy No. 1,594,929, or Bull No. 2,048,423, if those patents are presently understood. Nor of Hufford No. 1,537,944 as to the throttle steal element, which is the only aspect here involved, because Hufford (page 2, lines 71 et seq.) presents a clear statement of the conditions under which throttle steal is rendered possible by manipulation of the throttle valve, discussed above, and the means to compensate for the change in pressure below and above the governor valve by the action of the piston in the exterior chamber.
Benjamin did not disclose any knowledge of the presence of this problem, nor did he suggest a ...