Purposive construction and Cinderella’s glass slipper

Justin Negler and Sanjan Srivelan, Davies Collison Cave

CASE NOTE: Liberation Developments Pty Ltd v Lomax Group Pty Ltd [2019] FCA 1180

“Purposive construction” is now well entrenched in Australian judicial authority as a cornerstone to claim construction. However, as Lord Hoffman mused, there appears to exist “a tendency to regard [purposive construction] as a vague description of some kind of divination which mysteriously penetrates beneath the language of the specification”.[1]

In this vein we reflect on Liberation Developments v Lomax and the likely success a patentee may have in stretching the scope of their monopoly through purposive construction.

We also consider the risks of asserting to customers that the actions of a competitor constitute infringing behaviour.

The patent

Australian Patent no. 2013100057 (the Patent) relates to a “weighted support assembly” developed by Liberation Developments, which may be used for supporting hoarding systems. Hoardings are used around construction sites to fence or screen the public from restricted areas. In developing this assembly the inventor identified that prior art systems may “become unstable and prone to being knocked over if weights are removed from the base or even knocked off the base”.[2] Principally, the assembly claimed in the Patent comprises weights, a base and an elongate support member.


Of significance in relation to the issue of purposive construction are the following two features of claim 1:

  1. “a number of weights that can be placed on the base”; and
  2. “an elongate support member fixed to the base for supporting a post of a hoarding in an upright orientation”.

The alleged infringement

Lomax distributed an alternative hoarding system, which is pictured in the decision.

Two key aspects of the Lomax system to note are:

  • the weights of the Lomax system rest directly on the ground, such that there is no discrete or separate base, as is the case in the embodiments illustrated in the patent; and
  • the post and support member of the Lomax system slot into recesses and holes in the weights, respectively. It was in dispute whether this arrangement resulted in the support member and/or post being restrained in all degrees of freedom, such that the elongate support member is “fixed” to the base.

Construction of the claims

In enunciating the principles of claim construction Greenwood J made the following points (paraphrased for brevity):[3]


  • the starting point for construction is the wording of the claim;
  • recourse to the specification is not conditioned upon first finding ambiguity in claim language; and
  • a patent specification (including, of course, the claims) should be given a “purposive construction” rather than a purely literal one.


However, Greenwood J tempered these statements by adding that “‘purposive construction’ is not a mechanism for demonstrating that the glass slipper actually does fit on Cinderella’s sister’s oversized foot and thus Cinderella’s sister is Cinderella, when it does not and she is not.”[4]


To establish infringement, Liberty Developments needed to show that the Lomax system comprised a “base”. They argued that, given the nature of the disclosure and specifically that the specification does not express a limitation that the base cannot be a weight,[5] purposive construction of the claims would indicate that the word “base” should encompass a weight that was a “lowermost or supporting part”[6] of the assembly.


However, Greenwood J found that the context of the specification could not displace the wording of the claim, which according to him “suggests a conscious distinction and separation between a base on the one hand and a weight on the other”.[7] Clearly, in Greenwood J’s view, the glass slipper would not fit from this angle.


Notwithstanding the foregoing, assuming there existed a “base” in the Lomax system, feature 2 of the claim required that the “elongate support member” be “fixed” to the base. Liberation Developments argued that in light of the problem that the invention sought to solve, the word “fixed” should be limited to mean that only lateral movement is inhibited in the sense, at least, that the weights are inhibited from “being knocked off”.[8]


Again, Greenwood J was unable to read the context of the specification into the claim and instead adopted a more literal approach. Specifically, he was unable to accept that if the “member can simply be lifted out of the assembly”, that it could also be considered “fixed” to the base, as described in the claim.[9] It appears Greenwood J does not take kindly to stretching glass slippers.

Unjustified threats against 3rd parties

The court also heard Lomax’s cross-claim that an entity associated with Liberation Developments made a representation to a third party constituting an unjustified threat.


The specific comment that Lomax objected to was in a letter to Mirvac from Mr Bloom of Liberty Developments and Titan (exclusive licensee of Liberty Developments). In this letter Mr Bloom wrote, “currently the dispute is confined to Titan and Lomax. Titan sincerely does not want to involve any other persons in this dispute.”[10]


The primary question before the court was whether this amounted to a threat. Greenwood J applied C & P Development Coy (London) Ltd v Sisabro Novelty Coy Ltd,[11] which provided that it is not necessary to make a threat explicitly, but “it is enough if the language used is such as would convey to any reasonable man that the person using the language intended to bring proceedings for infringement against the person said to be threatened.”[12] Greenwood J found that what amounts to a threat is a question of fact,[13] but it is not necessary to explicitly state as much, so long as the meaning would be conveyed to a reasonable person.[14]


Greenwood J also considered CQMS Pty Ltd v Bradken Resources Pty Limited.[15] In this case, the applicant sent letters to the customers of the respondent containing the following:[16]


By selling certain components of the Penetrator Max products to its customers to be used as GET, BKN has infringed, and authorised the infringement of, the patents.  However, CQMS’ dispute is with BKN not with the customers who use the GET. [emphasis in original]


The judge distinguished the present case on the basis that the letter in CQMS was a general letter to the industry and not a “single bilateral communication”.[17] He also found that the wording of the letter, at most, contained an “observation that the applicants might need to consider their position according to changing circumstances but it does not contain a direct or indirect threat to Mirvac of infringement proceedings against Mirvac.”[18]

Lessons from the decision

From this decision we can conclude that a purposive construction does not allow the meaning of a claim to be extended beyond the meaning of the words in the claim when read in conjunction with the specification more broadly.[19] We return again to the words of Lord Hoffman and a perhaps more modest view of purposive construction being that it merely allows a “person to be taken to mean something different when he uses words for one purpose from that he would be taken to mean if he was using them for another.”[20] Although “purposive construction” has a role to play, the scope of the claimed invention is first and foremost demarcated by the words of the claims themselves.


In this decision it is also worth noting that there were no particularised definitions in the body of the specification for the words in contention. More particularly, the word “fixed” only appeared thrice and so the judge was left in a relative vacuum in which to interpret the claims. As a result, extensive use was made of the Oxford English[21] and Macquarie Dictionaries[22]. It is, of course, always much easier with the benefit of hindsight to see where more flesh could have been added to the bone.


In relation to unjustified threats, it is apparent that there is a fine line between what is and is not a threat. It would, therefore, be prudent not to assert infringement in case it may give a party cause to wonder about their position.


To read more about the Federal Court’s views in an earlier decision, please click here.

[1]  Liberation Developments Pty Ltd v Lomax Group Pty Ltd [2019] FCA 1180, [97] (“Liberation Developments v Lomax“) quoting Hoffmann LJ in Kirin Amgen Inc v Hoechst Marion Roussel Ltd (2004) 64 IPR 444.
[2]  Ibid [7].
[3]  Ibid [97].
[4]  Ibid.
[5]  Ibid [72].
[6]  Ibid.
[7]  Ibid [108].
[8]  Ibid [81].
[9]  Ibid [115].
[10] Ibid [141].
[11] (1953) 70 RPC 277.
[12] Liberation Developments v Lomax, [148] quoting C & P Development v Sisabro Novelty, 282.
[13] Liberation Developments v Lomax, [150] citing Brian v Ingledew Brown Bennison & Garrett (a firm) [1996] FSR 341, 349; Occupational and Medical Innovations Ltd v Retractable Technologies Inc (2007) 73 IPR 312.
[14] Liberation Developments v Lomax, [148] quoting C & P Development Coy (London) Ltd v Sisabro Novelty Coy Ltd (1953) 70 RPC 277.
[15] (2016) 120 IPR 44.
[16] Liberation Developments v Lomax, [152].
[17] Ibid [170].
[18] Ibid.
[19] Ibid [97].
[20] Ibid.
[21] In the decision the following definition from the Oxford English Dictionary was recorded: “Adjective – placed or attached firmly; fastened securely; made firm or stable in position.  In relation to a person or his or her countenance:  made rigid or immobile.  A further meaning is:  definitively and permanently placed; stationary or unchanging in relative position.  Two examples given include fixed star meaning a star which appears always to occupy the same position in the heavens and fixed property meaning that which consists in immovable as land and houses.”  (Emphasis in original).
[22] In the decision the following definition from the Macquarie Dictionary was recorded: “Adjective – made fast or firm; firmly implanted; rendered stable or permanent, as colour; set or intent upon something; steadily directed; set or rigid; definitely and permanently placed; permanently established; definite; not fluctuating or varying.  Examples are given of the term in particular disciplines.” (Emphasis in original).


Author: Justin Negler and Sanjan Srivelan, Davies Collison Cave

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