Each claim is a list of features
A claim defines an invention as a set of features, sometimes called integers. A simple example, for an invention we'll make up, might read like this: "A pet water bowl comprising a reservoir, a drinking tray below the reservoir, and a float valve controlling the flow of water from the reservoir to the drinking tray."
That claim has three features: the reservoir, the tray below it and the float valve controlling the flow. The word "comprising" means "including at least". A bowl with all three features and something extra, such as a filter, still falls within the claim.
The basic rule follows from this. To infringe a claim, a product or process generally has to have every feature of the claim. A water bowl without a float valve doesn't infringe this claim, however similar it looks. It also works in reverse when the patent is examined: a claim is not new if a single earlier document discloses every one of its features.
Fewer features means broader protection
The fewer features a claim has, the more products fall within it and the broader the protection. Take away the float valve and the claim would cover any bowl with a reservoir above a tray, which is far broader. Add a requirement that the float valve be made of a particular material and the claim becomes narrower, easier for a competitor to avoid, but also harder to attack.
That is the central tension in claim drafting. A broad claim is more valuable if it survives, but more likely to be anticipated or made obvious by prior art. A narrow claim is more likely to survive but easier to design around.
Independent and dependent claims
The answer is not to choose one or the other but to have both. Claim 1 is usually an independent claim: it stands alone and defines the invention at its broadest. Later claims are often dependent claims, which refer back to an earlier claim and add a feature, for example: "The pet water bowl of claim 1, wherein the float valve comprises a buoyant member pivotally connected to a valve seat."
A dependent claim includes every feature of the claim it refers to, plus its own. A set of claims therefore forms a ladder from broad to narrow, with each step adding a feature that makes the claim more specific and harder to attack.
A well-drafted application will also have several independent claims covering the invention from different angles: the product, a method of making or using it, and sometimes a system or kit including it. A competitor who avoids one may still fall within another.
The broad claim is what you hope to get. The narrower claims are what you can still get if the examiner finds something close.
How fallback positions work in examination
Fallback positions show their value when the examiner cites prior art. Suppose the examiner finds an earlier water bowl with a reservoir, a tray and a float valve. Claim 1 is no longer new. If the earlier bowl's float is fixed rather than pivoting, though, the dependent claim above may still be new and inventive. We can respond by amending claim 1 to include the pivoting feature, giving up some breadth to keep a valid claim that still covers the commercial product.
The description is the further reserve. Any feature described there in enough detail can be brought into a claim by amendment, even if it was never in a dependent claim, provided it was clearly disclosed in the specification as filed. That is why we write detailed specifications. Every specific technical feature described is a potential point of distinction against prior art an examiner hasn't found yet. A thin specification may leave nothing to amend towards.
This only works if the support is there from the start. New matter can't be added after the complete application is filed, and a feature added at that stage won't have the provisional's priority date. We explain why in can you prepare a patent application yourself?.
Reading someone else's patent
If you are worried about a competitor's patent, the same principles apply. Look at the claims, not the title, abstract or drawings, which can be much broader than what is actually protected. Start with the independent claims and check whether your product has every feature of at least one of them. If it lacks even one, that claim is generally not infringed, although Australian courts can look past purely immaterial differences. Check too whether the patent has been granted, whether it is still in force and whether it covers the country you operate in. Pending applications, lapsed patents and patents granted only overseas carry very different risks.
These questions are rarely straightforward, and a misreading in either direction can be expensive. If a competitor's patent is a concern, it is worth getting advice before you change your product or your plans.
How we draft claims
At Patentec we draft the claims before the description, typically 20 or more claims from broad to narrow across several independent claims. We then write the description around them so that every claimed feature, and many more that could become claims, is explicitly supported. We set out the full process in our approach to patent applications.
If you would like help understanding the claims of your own patent application, or someone else's patent, contact Patentec for a free initial consultation.