Scottish Court of Session Decisions

In this case the Pennycook Patent Glazing and Engineering Company (Limited) and Charles H. Pennycook sought to have Mackenzie, Harley, & Company, the British Patent Glazing Company, and Messrs Mackenzie and Harley, the individual partners of both firms, interdicted from infringing certain letters-patent granted to Pennycook, and assigned by him to the Pennycook Company. The respondent Mackenzie was in the employment of Pennycook as book-keeper from about the beginning of June 1878 till 1st January 1879, when he was assumed as a partner by Pennycook, with whom he continued in partnership till about the month of August 1880, when he entered into a copartnery with the respondent Harley.

The invention patented was for “new or improved constructions of self-glazing or glass-fixing sheet-metal bars for window sashes, roof and frame lights for greenhouses, garden frames, vineries, conservatories, sheds, and other structures where glass is required for the admission of light.” And the specification bore that the invention related “to the bending or doubling and drawing or shaping of long strips of thin sheet-zinc, or other metal, through shaping dies, or the rolling through between shaping rollers, or it might be partly both, into the form of ‘astragals’ or glass retaining bars, for the frames of windows, or glass roofs, or like structures for the admission of light, for self-glazing these without the use of putty or other plastic ‘fixing,’ which sash bars or astragals secure the glass much more easily and efficiently, or tightly, and prevent the admission of water or moisture drops more effectually than by the astragals or modes and means heretofore practised for fixing the glass; at the same time they allow for the free expansion and contraction of the glass and metal without risk of breakage; and which are stronger than astragals heretofore constructed.” The body of the astragal consisted of two long strips of zinc or other firm sheet metal. One of these strips was doubled throughout the centre of its length, its two thicknesses being for the most part pressed close together, but with the outer edges forming narrow wings, so that a transverse section of the strip resembled an anchor or the capital letter T inverted and with its arms curved upwards. The second strip was so shaped that it covered entirely the lower or convex side of these arms or wings, and then passing over their edges followed the line of their upper or concave sides almost reaching to the perpendicular central portion of the first strip. Upon the concave sides of each of the wings, and underneath the corresponding portions of the second strip, there was then inserted a strip of lead or other ductile metal, which on reaching the central perpendicular portion of the first strip, passed up that portion to its top, one strip of lead being on each side. The whole astragal or compound bar so put together was drawn through the hole in a draw plate of the shape of a section of the complete astragal, so as to compress the curved wings together and grip sheets of lead tightly between the upper and under strips of zinc forming the wings. The whole thus became long rigid astragal bars ready for being cut into lengths to suit the sashes or other frames of the structure to which the glass was to be fitted. The astragals were then fitted into the frames at the desired distances apart to suit the widths of glass which were to be used. The glass rested on the lateral wings of the astragal and its edge touched the vertical central portion. The strips of lead, in so far as above the glass, were then folded down so as to compress the glass firmly against the lateral wings and hold it in position without the use of putty. The specification concluded thus:—“Having thus described the nature of my invention and the manner of performing the same, I have to state that I do not confine myself to the precise details herein described or delineated, but what I consider novel and original, and therefore claim as the invention secured to me by the hereinbefore in part recited letters-patent, is:— First, The general construction of shaping and putting together of the parts of zinc or other sheet-metal sash-bars or ‘astragals,’ for securing the sheet-glass of windows, roofs, conservatories, and other such like structures—all substantially as herein described, in reference to and shown in the accompanying drawings, or any mere modifications thereof. Second, The construction of sheet-metal sash-bars or ‘astragals,’ with doubled over thicknesses of the sheet-metal for gripping strips of sheet-lead, copper, or other like ductile metal, for securing or glazing the sheets of glass on these ‘astragals’—all substantially as herein described, in reference to and shown in the accompanying drawings, or any mere modification thereof. Third, The construction and use of sheet-metal sash-bars or ‘astragals,’ with strips of sheet-lead, copper, or other like soft or ductile metal, for folding down over and securing or glazing the sheet-glass to such ‘astragals,’ without putty or other cement for windows, roofs, conservatories, or other such structures for the transmission of light—all substantially as herein described, in reference to and shown in the accompanying drawings, or any mere modification thereof.”

The astragal which was alleged to be an infringement of this patent was likewise the subject of letters-patent which were subsequent in date to Pennycook's. In it, in place of zinc or other sheet-metal, a solid iron bar was used, but this bar was also shaped so that its transverse section resembled an anchor, and the glass was held in position by an overlapping sheet of lead, which pressed it down on to the arms of the bar, exactly as in Pennycook's system. The lead, however, in place of being gripped between the two zinc folds of the arms, consisted of a single sheet which was kept firm by passing round the entire surface of the iron bar, except the top of

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the central vertical portion, where the two edges of the sheet almost met; and, of course, when the glass was fitted in so much more of the vertical portion of the iron was laid bare as had been covered by the lead used to fix the glass.

The respondents averred, inter alia, that “the alleged invention specified and described in the letters-patent founded on had been publicly exhibited by the complainer Charles Hill Penny-cook, and was publicly known in Great Britain prior to the date of the said letters-patent. It was so publicly exhibited by the complainer on Glasgow Green, at the exhibition of the Glasgow Agricultural Society, on 7th, 8th, and 9th May 1879.” And they pleaded—“(2) The alleged letters-patent founded on by the complainers are null and void or invalid, because … publicly known prior to the date of the said letters-patent. … (3) Assuming the letters-patent founded on to be valid, the note should be refused, because the respondents have not infringed the said letters-patent.”

On a proof the following was the most important evidence with reference to the first of the above-quoted pleas-in-law. The complainer Pennycook stated in cross-examination—“There was an exhibition of the Glasgow Agricultural Society held in Glasgow Green in May 1879. I made exhibits at that exhibition. Amongst the exhibits made on that occasion by my firm were astragal bars of various drawn materials. There were none exhibited which fell under the specification of the letters-patent, which I afterwards obtained. There was nothing showing the combination of zinc or other hard metal with soft metal. I believe my invention was in process of being made at that time, but I do not think any of it had been made in a state in which it could be exhibited. (Q) Were none of those patterns which have been shown to you, as produced under your letters-patent, shown to the public at that exhibition ?—(A) There were none in a finished state. (Q) In what respect were they unfinished ?—(A) They were in a semi form; the thing was not matured.” The respondent Mackenzie being at the time to which his evidence refers a member of the complainer's firm, stated with reference to an astragal of the complainer's system—“We exhibited these to every person to whom we could get an opportunity of showing them. It was Mr Pennycook who principally did so. He gave away a great many specimens. He explained the novelty most completely. (Q) To whom ?—(A) In a show where thousands were passing. I cannot individualise, but he explained it to all to whom he had the opportunity of doing so. No. 61 is a handbill of Pennycook, Sons, & Co., which was printed specially for the show. The ‘self-glazing astragal bars’ there mentioned refer to the bars which Pennycook subsequently patented. The handbill is headed ‘Charles Hill Pennycook, patentee.’ He was a patentee at the time, but not of astragal bars. He explained to me his reason for putting in the word ‘patentee,’ viz., that it would blind the eyes of the public to the fact that the astragal was not patented when we exhibited it.” In corroboration the respondents produced two witnesses who spoke to seeing in Pennycook's possession at the show astragals of the kind he afterwards patented. One of these witnesses only could state that he heard Pennycook describe the nature of his invention.

The Lord Ordinary (Rutherfurd Clark) repelled the reasons of suspension and refused the note.

His Lordship added this note:—“The patent is assailed on various grounds. But after the proof it was evident that the only important challenge depended on the allegation that before the provisional specification was lodged the patentee had himself published the invention by exhibiting the patented articles at the show of the Glasgow Agricultural Society on 7th, 8th, and 9th May 1879. In the opinion of the Lord Ordinary the allegation has been proved. If the witnesses for the respondents are speaking the truth, it is plain that the patent is bad; and the Lord Ordinary sees no reason to doubt either their accuracy or their honesty.

“After the evidence of the respondents was closed, the complainers asked for an adjournment in order to lead proof in replication. But considering that they had received explicit notice on record, and that they had entered on the point in their evidence-in-chief, the Lord Ordinary refused the motion. He did not think it right that the complainers should have an opportunity of seeking out the evidence with which they should have been prepared at the beginning of the case.

“If the Lord Ordinary is right so far, there is, of course, an end. But even if the patent were valid, he is of opinion that there has been no infringement. The letters-patent are granted for a ‘New or improved construction of self-glazing or glass-fixing sheet-metal bars for window sashes, roof and frame lights for greenhouses, garden frames, vineries, conservatories, sheds, and other structures where glass is required for the admission of light.’ The specification sets out that the ‘invention relates to the bending or doubling and drawing or shaping of long strips of thin sheet zinc or other metal …. into the form of astragals, or glass retaining bars for the frames of windows …. for self-glazing these without the use of putty,’ &c. It proceeds to state that the astragal is made by bending two pieces of sheet metal into such a form as that they fit into one another. One of them is so constructed as to furnish a ‘clip’ to receive and grip the sheet lead, which is folded down on the glass after it is laid on the astragal. In this way putty is dispensed with.

The claiming clauses are in accordance with the title and description. They claim, 1st, the general construction of sheet-metal sash bars or astragals; 2nd, the construction of sheet metal sash bars or astragals with the arrangement for gripping strips of sheet lead or other ductile metal, or, in other words, the ‘clip;’ and 3d, the construction and use of sheet-metal sash bars or astragals with strips of sheet lead or other ductile metal. They include the construction of the sash bars with or without the clip, and the use of sheet lead or other ductile metal with such sash bars. But they do not comprehend any other sash bars than those which are made of sheet metal. If they did they would go beyond the letters-patent, which are granted for ‘sheet-metal bars’ only.

The astragal or sash bar which, as made by the respondents is formed not of sheet metal but of solid iron rolled out into the requisite shape.

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It is constructed in a single piece, being or at least resembling what is known as a T iron bar. The bar thus formed is surrounded with a closely-fitting envelope of sheet lead. It is placed in situ with the head of the T undermost, so that the wings on either side of the leg support the glass. The lead which lies along the leg of the T is folded down on the glass.

“Special advantages are claimed for this form of construction, both as regards the length and the strength of the bars. The Lord Ordinary is disposed to think that those advantages are attained; but whether they are or not, he cannot hold that the respondents' bars are a contravention of the complainers' invention, which consists in the construction of sash bars from the peculiar form which is given to strips of sheet metal. It is said that they are a mechanical equivalent. But it seems to the Lord Ordinary that there is no place for such a doctrine here. The patent includes no other bars than sheet-metal bars, and therefore excludes every other form. To hold that it comprehends bars rolled from solid iron would be to extend it to bars which the patentee had not indicated as suitable for his purpose, and to bars which, so far as appears from the specification, could not be availably used. Nor is the use of a soft metal, as a substitute for putty or other plastic material, the subject of a separate claim. It is only claimed in connection with the bars of the specified construction.”

The complainers reclaimed.

At advising—