Interlego AG v Toltoys Pty Ltd

HIGH COURT OF AUSTRALIA

. Stephen J. Barwick C.J., Menzies and Mason JJ.

INTERLEGO A.G. v. TOLTOYS PTY. LTD.

(1973) 130 CLR 461

7 December 1973

Patents

Patents—Subject matter—Whether claim to monopoly forms part of prior art—Interpretation of claim—Circumstances in &hich body of specification may be referred to—Description of invention in claim—Uncertainty—Patents Act 1952-1966 (Cth), s. 40 (1) (a).

Decisions

1973, January 5.
STEPHEN J. delivered the following written judgment :-
Interlego A.G. is the patentee under Australian Letters Patent No. 229,550 for an invention for "Improvements in and relating to toy building sets and building blocks" and sues for infringement by the defendant, Toltoys Pty. Ltd., of its monopoly. Toltoys counterclaims for revocation of the first claim contained in Interlego's letters patent upon a number of grounds. (at p462)

2. Each of the parties markets sets of children's building blocks made of plastic, brightly coloured and predominantly of cuboid shape, a feature of which is that the blocks will interlock securely with one another so that simple structures may be built with them. (at p462)

3. The plaintiff's "Lego" blocks are constructed with one or more, usually at least four, solid, circular, flat topped projections ("primary projections") on their top surface, the bottom of the block being open and, in all but the very smallest size block, containing within the cavity of the block one or more projections ("secondary projections") each of which takes the form of a hollow cylinder reaching down to the open bottom of the block and having an open end at its extremity. (at p462)

4. These blocks may be securely interlocked when placed directly one on top of another because the external surface of each secondary projection within the open end of the upper block will clamp between opposing external surfaces of four primary projections on the upper surface of the lower block. When not positioned the one directly over the other but rather so that one projects out over the base of the other, clamping may still be obtained but this may involve only two or, in certain positions, one primary projection being clamped against the external surface of a secondary projection. In such cases the internal surfaces of the walls of the upper block play an essential part in the clamping process and in the case of the first interlocking arrangement described above, when four primary projections are engaged against the external surface of a secondary projection, those walls add a further clamping surface and prevent rotational movement. All these instances of clamping action I shall refer to as cross-sectional clamping, as distinct from a male-female form of clamping. In the case of the very smallest Lego block, which lacks any secondary projection and has but one primary projection, it may be interlocked on top of another block by clamping the open cavity at its bottom over a primary projection, thus interlocking by means of a male-female clamping action ; there also exists a wide, shallow block, rather in the form…