The goal of a claim is to define the scope of protection of a patent. The claim needs to be clear and understandable so that infringers or your competitors can know if they are infringing on your patent or not. Otherwise, your patent will the invalid for being indefinite.
To make the claim clear, the words of the claim need to be used consistently. For example, if the claim recites a BOLT, don’t, later on, call it a “THREADED FASTENER.” Everyone will be confused as to whether the THREADED FASTENER refers to the BOLT or to a different component of the claimed invention.
To learn the basics of claim drafting, read How to write a claim for a patent application?
How to refer to the same part in the claim?
If your invention has a component (e.g., bolt), then you want to introduce the component with the word A. For example, you would write A COMPONENT the very first time that the component is mentioned in the claim. After that, each time you refer to the component you want to use the word THE. For example, a claim might read:
A tripod for supporting a camera, the tripod having legs.
As you can see, the tripod was initially introduced with the word A. But after that, when I used the term tripod I referred to the tripod with the word THE. By doing so, it’s clear that THE tripod referred to A tripod.
Read more about How to use A, THE, and SAID in a claim?
How to refer to multiple parts that are the same?
Sometimes, your invention may have multiple components that are the same. For example, a tripod has three different legs. These legs are typically the same but in different orientations.
Don’t call them out as three legs. By doing this, you can’t specify any of the differences between the legs. Instead, you should individually call out each leg in the claim. For example, the three legs would be referred to as a first leg, a second leg, and a third leg.
This may seem overly tedious but it’s necessary to ensure that the claim is clear. The goal of the claim is not to make your job less tedious, it’s to make the claim clear to potential infringers.
No one can confuse the second leg with the first leg or the third leg. They are each individually called out. By introducing the first leg, the second leg, and the third leg, you can easily point out any differences between the first, second, and third legs by simply specifying whether you are referring to the first, second, or third leg.
How to name a part of the invention?
A part can be named in many different ways. For example, a bolt can be called out as a bolt, fastener, threaded fastener, or even an attachment device. Which one should you use?
When you’re beginning to learn to write a claim, you should not start with the broadest term. You’ll make the claim confusing for everyone when they’re reading your claim. I recommend that you start with the narrowest term. Don’t worry about if your claim is broad or narrow. You aren’t at the skill level where you should be worried about the breadth of the claims. To figure that out, you need to understand various patent concepts such as patent infringement, claim interpretation, the doctrine of equivalents, and the broadest reasonable interpretation among other things.
After writing the first draft of the claim, reread the claim and figure out which terms need to be made broader and which terms need to remain narrow.
The goal of the first draft of your claim is not to come out with a perfect claim that is extremely broad. Rather the goal is to write a claim that is clear. You can then revise parts of the claim to control the breadth and narrowness of the claims as you see fit.