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Claiming Use of an Object

The meaning of a patent claim is crucial.  If the claim describes something which is already known it is invalid and unenforceable.  When drafting a claim it is very important to know how it will be interpreted by a Patent Office, and more importantly, by a Court. 

A common form of claim commences “A [device] for [a particular purpose] …..”.  Such claims have been interpreted by the Courts on a number of occasions, and the established legal meaning of such a claim is “A [device] which is suitable for [a particular purpose] ….”.  The importance of understanding the correct interpretation can be illustrated by giving a few examples. 

A hook having features A, B and C
Clearly, there is no limitation on the kind of hook being claimed, and any hook having the full compliment of features A, B and C will fall within its scope.  Regardless of its function, if a hook having these features was already public knowledge when the patent application was filed the claim will be invalid. 

A hook for a crane, having features A, B and C
The accepted meaning of this claim would be “a hook which is suitable for a crane, having features A, B and C”.  The meaning of “a crane” is well understood, and a Court should have little difficulty in deciding what a crane is.  A fish hook is clearly not suitable for use with a crane because of its dimensions and strength, and even if it possesses all of the necessary features A, B and C it will not fall within the claim.  In the case of an earlier disclosure of such a fish hook the claimed invention will still be regarded as novel. (There might, however, be lengthy legal argument about whether it would be obvious to apply features known in relation to fish hooks to crane hooks!) 

A hook for lifting heavy objects, having features A, B and C
On first sight it might appear that this would exclude fish hooks.  However, words like “heavy” are relative.  A salmon is heavy in relation to a minnow.  Such relative terms are generally disregarded by patent examiners.  It is very unlikely that such a claim would be held to exclude fish hooks.

Another very useful way of claiming the use of an object is “A [device] when used in [a particular process] ….”.  Such a claim is legally construed as confining the scope of the claim to the specified use. To give another example:

A hook when used in lifting roof tiles stacked on a pallet, having features A, B and C
This claim is limited to the particular use in question, i.e. lifting roof tiles stacked on a pallet.  Therefore, even if the kind of hook possessing features A, B and C is already known for catching fish, the claim is still valid provided the specified use is not previously known, or obvious.

© Craske & Co., 2009

Last updated: 27 December 2010