Shave v H V McKay Massey Harris Pty Ltd [1935] HCA 39;
[1935] HCA 39
At a glance
Source factsCourt
High Court of Australia
Decision date
1935-06-11
Before
McTiernan JJ
Source
Original judgment source is linked above.
Judgment (23 paragraphs)
Shave v H V McKay Massey Harris Pty Ltd [1935] HCA 39; (1935) 52 CLR 701 (11 June 1935)
Shave Plaintiff, Appellant; and H. V McKay Massey Harris Proprietary Limited Defendant, Respondent.
This is an appeal by the plaintiff, in an action for infringement of a patent, from a judgment dismissing the action. The patent, which dates from 8th May 1924, was granted to the plaintiff in respect of "an improved reversible stump-jump disc plough." The defendants are manufacturers of agricultural implements. They have put on the market a stump-jump disc plough, the discs of which are reversible. The defendant's plough, which is constructed on the same or similar principles to the implement which embodies the plaintiff's invention, is alleged to be an infringement of the first claim of his specification. J., who tried the action, decided that the defendant's plough did not amount to an infringement of the invention covered by the plaintiff's claims. The defendant attacked the validity of the plaintiff's patent, but unsuccessfully. The decision of J. upholding the patent was, in our opinion, clearly right and calls for no further discussion. The issue upon the appeal is substantially whether, upon a proper construction of the plaintiff's claim 1, the defendant's plough amounts to an infringement. Prior to the plaintiff's invention, stump-jump disc ploughs were well known. Disc ploughs, the discs of which were susceptible of automatic reversal, were not unknown. But no plough had been devised which combined the actions of stump-jumping and automatic reversing. A disc cultivator existed in which the discs might be reversed and possessed a stump-jump action, but the reversal required the unscrewing of nuts and was not automatic. The principle of stump-jump mechanism in the case of disc ploughs is to fit the disc or discs upon an arm the fore part of which is pivoted to the frame of the plough, which thus draws the discs. When the discs meet an obstruction the arm permits them to rise and mount it. Before the plaintiff's invention it appears to have been considered necessary to transmit some of the weight of the plough to the discs in order to contribute to their digging into the ground both when commencing a furrow and after jumping an obstacle. This was done by means of spiral springs surrounding a rod descending vertically from the frame to the arm upon which the discs were mounted and meeting it at a point in the vicinity of the axle of the disc. Accordingly the arm was pivoted to the frame of the plough near its fore part so that the disc would be under the frame. Reversing mechanism was less common. The object of reversing the disc of a plough is to cause it, as the plough is drawn up and down a field, always to throw the upturned earth in the same direction. The discs are concave or dished-in on one side. They are placed diagonally to the direction of the plough with the concave side forward. A disc thus throws the earth over in the direction of its concave side. If the disc does not reverse and the plough is turned at the end of a furrow, the earth in the new furrow is turned over on the other side. The plaintiff constructed a plough in which he dispensed with any means of transmitting any part of the weight of the plough to the disc. He relied on the weight of the disc, its shape, and its diagonal position together with the direction in which the tractive force was applied, which, by the lowness of the axle, was made almost horizontal. He was thus able to draw the disc or discs behind the frame of the plough and pivot the stump-jump arm behind the axle and even lower than the axle. In the arm so pivoted he made the actual arm or rod upon which the disc axle is fixed rotate. By a lever he was thus able to reverse the disc. Discs had previously been thrown over from one side to another on an arm pivoted in the direction of the plough's movement. But the only instance in which, prior to the plaintiff's invention, a disc reversible in this manner was drawn after the plough frame is that of an altogether impracticable American invention never put into effect in Australia. The specification was, however, found in a library and cited as an anticipation. It has no stump-jump mechanism. The specification does not suggest the plaintiff's plough and may be ignored.