Patent Task§ JOURNAL · Tutorial
US Patent Claims Example: Independent and Dependent Claims Explained
An independent patent claim states a combination without referring to another claim. A dependent claim refers to an earlier claim, incorporates its limitations and adds a further limitation. For US applications, that dependency is addressed in 35 U.S.C. § 112(d).
The worked example below uses a fictional positioning clamp to explain claim structure, support and revision. It is an editorial teaching example, not a granted claim, client invention or recorded AI output. No prior-art search or patentability assessment has been performed. Its limitations demonstrate a reading method, not a recommended protection strategy for a real device.
Use the invention disclosure template to assemble your own source facts. The US patent drafting guide explains how claims connect to the specification, abstract, figures and editable Word document.
The disclosure behind the example
These source labels make the review traceable. They are worksheet identifiers, not paragraph numbers from an application.
| Source | Disclosed fact |
|---|---|
| D1 | A positioning clamp has a base, a fixed jaw mounted on the base, and a movable jaw. |
| D2 | The base has a guide slot along which the movable jaw is guided. |
| D3 | A screw advances the movable jaw toward the fixed jaw. |
| D4 | The fixed jaw and the movable jaw each have a V-shaped locating groove; the grooves oppose each other to receive a cylindrical workpiece. |
| D5 | Replaceable contact pads are provided at those locating surfaces. |
The source does not specify screw engagement, pad attachment, pad material, groove angle or dimensions. There are no force, accuracy or durability measurements. Keep those gaps visible even where the high-level claim wording sounds plausible.
Independent claim example
1. A workpiece-positioning clamp comprising: a base having a guide slot; a fixed jaw mounted on the base; a movable jaw guided along the guide slot; and a screw arranged to advance the movable jaw toward the fixed jaw, wherein the fixed jaw and the movable jaw have opposing V-shaped locating grooves for receiving a cylindrical workpiece.
The claim introduces an apparatus, lists components and defines relationships between them. The following annotations explain this example; they do not establish that any particular feature is sufficient or necessary for a real claim.
| Claim wording | Role in the sentence | Review question |
|---|---|---|
| “A workpiece-positioning clamp” | Identifies the claimed object | Does the source describe an apparatus of this kind? |
| “comprising” | Introduces the listed elements | What combination is actually defined after the transition? |
| “a base having a guide slot” | Introduces a part and its feature | Where is the slot described, and how does it guide the jaw? |
| “a fixed jaw” and “a movable jaw” | Distinguishes two components | Do the description and drawings preserve those identities? |
| “a screw arranged to advance” | Connects an actuator to movement | Does the implementation account explain its actual engagement? |
| “opposing V-shaped locating grooves” | Defines the locating geometry and relationship | Is the geometry disclosed, and is this limitation appropriate for the intended scope? |
“Comprising” is generally open-ended in US claim interpretation, as discussed in USPTO MPEP § 2111. It does not erase the listed limitations or supply technical support for them. A useful claim still needs to be evaluated as a whole.
The USPTO utility application guide describes each claim as a single sentence and discusses numbering and dependent forms. The semicolons above help separate elements within that sentence; they are not a substitute for clear relationships.
Dependent claim example
2. The workpiece-positioning clamp of claim 1, wherein each of the opposing V-shaped locating grooves is provided with a replaceable contact pad.
Read claim 2 as the entire combination of claim 1 plus the added pad limitation. It does not replace the grooves or remove the screw. In this exercise, D5 supplies the additional fact. Whether pads belong in an independent claim, a dependent claim or another formulation requires analysis of the actual invention and prior art.
A dependency error is easier to see in a counterexample:
Not a suitable dependent formulation for this exercise: “The clamp of claim 1, wherein flat locating surfaces replace the V-shaped grooves.”
That sentence attempts to replace a limitation inherited from claim 1. It does not simply further limit the same combination. It also introduces an alternative that is not part of D1–D5. Do not make it “valid” by silently rewriting the source disclosure.
Build a support map before broadening or narrowing
Download the claim support worksheet (Markdown). Complete it with your own disclosure version, actual passages and review decisions. No account is needed to download the blank file.
US written-description and enablement requirements arise under 35 U.S.C. § 112(a); distinct claiming is addressed in subsection (b). The USPTO written-description guidance explains that written description and enablement are separate inquiries. Matching a phrase to an input sentence is a useful first check, not a complete legal assessment.
| Claim feature | Source in this exercise | Next check in a real draft |
|---|---|---|
| Base, fixed jaw mounted on the base, and movable jaw | D1 | Record the actual description paragraphs and views |
| Guide-slot movement | D2 | Confirm the guide relationship is explained, not merely named |
| Screw advances movable jaw | D3 | Obtain the missing engagement and retention details |
| V-shaped grooves on the fixed and movable jaws, opposing each other | D4 | Check the geometry and terminology across the drawing set |
| Replaceable pads in claim 2 | D5 | Clarify how the pads attach and can be removed |
| A specified alloy or 90-degree groove | No source | Keep unresolved; do not insert a plausible value |
| A stated percentage improvement | No test evidence | Do not invent a measured result |
In a live matter, replace D1–D5 with the actual source version and location. Then record where the information appears in the draft. If the tool creates both the claim and a supporting paragraph from its own assumption, those two generated passages are not independent confirmation of the fact.
Distinguish claim support from Office Action claim mapping
The support worksheet above traces a proposed limitation to the inventor's source material and the draft description. An examiner-citation map serves a different purpose: it records what an Office Action says about a claim and checks the actual cited passage. A feature's basis in your disclosure and its alleged disclosure in a prior-art reference are separate questions.
For that later stage, see OA Review's Office Action claim-mapping guide and worked § 103 evidence comparison. OA Review is a separate product from the same team as Patent Task; following these resource links does not transfer documents or accounts between the products.
Use the claim version addressed by the action, confirm which claims are currently pending, and retain the application-as-filed record. Keep proposed amendments separate from the examined text. Content newly generated after filing cannot substitute for the original disclosure when assessing amendment support.
Review terminology and antecedent references
Track each component from introduction to later use. In claim 1, “a movable jaw” introduces the component; “the movable jaw” refers back to it. A later reference to “the gripping unit” would require the reader to work out whether this is the same part or a new component.
This simple check catches several practical problems:
- A new noun appears only in a dependent claim without a clear introduction.
- Two different components are given the same name.
- A term changes in the claims but retains its old name in the description.
- A reference sign points to different parts in different views.
A drawing reference-number register helps coordinate names and signs. Numbers alone do not explain structure or resolve an unclear technical relationship.
The antecedent-basis examples show how to distinguish two similar components and introduce a new component properly in a dependent claim.
Make one revision, then review its consequences
For this exercise, suppose a draft changes “replaceable contact pad” to “elastomeric contact pad.” D5 supports replacement, but it does not supply the material. The change also loses the original replacement limitation. A reviewer should record both effects rather than accept the new wording because it sounds more specific.
Use four passes for an AI-assisted revision:
- Source facts: identify additions, omissions and changed relationships.
- Claim form: check dependencies, component names and references.
- Description and figures: locate the support and inspect affected views.
- Scope: assess the revised combination against the actual contribution and verified prior art with the responsible practitioner.
Save the reviewed revision and reopen the exported document if the deliverable is Word. The drafting software evaluation checklist includes a controlled correction and export test.
Apply the method to a US drafting session
Complete the disclosure worksheet, then review the US drafting workflow and example. Confirm the technical plan and US jurisdiction, and keep your source notes alongside the editable claims. Use patent search to inspect relevant documents and preserve their actual sources.
How many claims should a US application contain?
There is no useful universal target for this exercise. The claim set should follow the disclosed subject matter and the practitioner's scope decisions. These two claims demonstrate a dependency, not a recommended claim count.
Is a longer claim more protective?
Not automatically. An added limitation may clarify the combination, narrow it or introduce unsupported matter. Examine its purpose and source rather than the word count.
Does fluent claim language prove patentability?
No. Clarity, disclosure support, novelty and nonobviousness require different analyses. This example helps you inspect claim language; it does not predict an examination outcome.