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Work location
Mechanical Engineer Needed to Design Soft-Close Door Hinge Pin Mechanism Ended
About the job
I’m looking for an experienced mechanical engineer to help with Phase 1: concept and feasibility for a retrofit soft-close mechanism for a residential door hinge.
The idea is a replacement hinge pin (with a small top module if needed) that uses a one-way clutch and rotary viscous damper to slow the last approximately 20° of door closing, while keeping near-zero drag on opening.
Scope (Phase 1 – Concept and Feasibility Only)
What I need in this phase:
* Feasibility review of a retrofit soft-close hinge pin / hinge-top module concept, including engage angle, torque curve, basic leak and wear risks, and practicality in the given envelope.
* Concept-level parametric CAD (native format plus STEP AP214/AP242) for all parts and the assembly.
* Two to three key views or simple renders that clearly show how the mechanism works.
* High-level DFM notes and BOM suggestions using off-the-shelf components where possible (one-way clutch, rotary damper, O-rings, springs, etc.).
* A brief prototype and test plan outline describing how you would build and test a V1 prototype (suggested process such as CNC or 3D printing, approximate materials, and basic test steps).
If this goes well, a separate follow-on project (Phase 2) may cover detailed production drawings with full GD&T, tolerance stack-ups, refined material and finish choices, and more rigorous reliability analysis.
Key Design Targets (Concept-Level Estimates)
I understand these will be targets and assumptions a... read more
The idea is a replacement hinge pin (with a small top module if needed) that uses a one-way clutch and rotary viscous damper to slow the last approximately 20° of door closing, while keeping near-zero drag on opening.
Scope (Phase 1 – Concept and Feasibility Only)
What I need in this phase:
* Feasibility review of a retrofit soft-close hinge pin / hinge-top module concept, including engage angle, torque curve, basic leak and wear risks, and practicality in the given envelope.
* Concept-level parametric CAD (native format plus STEP AP214/AP242) for all parts and the assembly.
* Two to three key views or simple renders that clearly show how the mechanism works.
* High-level DFM notes and BOM suggestions using off-the-shelf components where possible (one-way clutch, rotary damper, O-rings, springs, etc.).
* A brief prototype and test plan outline describing how you would build and test a V1 prototype (suggested process such as CNC or 3D printing, approximate materials, and basic test steps).
If this goes well, a separate follow-on project (Phase 2) may cover detailed production drawings with full GD&T, tolerance stack-ups, refined material and finish choices, and more rigorous reliability analysis.
Key Design Targets (Concept-Level Estimates)
I understand these will be targets and assumptions a... read more
I’m looking for an experienced mechanical engineer to help with Phase 1: concept and feasibility for a retrofit soft-close mechanism for a residential door hinge.
The idea is a replacement hinge pin (with a small top module if needed) that uses a one-way clutch and rotary viscous damper to slow the last approximately 20° of door closing, while keeping near-zero drag on opening.
Scope (Phase 1 – Concept and Feasibility Only)
What I need in this phase:
* Feasibility review of a retrofit soft-close hinge pin / hinge-top module concept, including engage angle, torque curve, basic leak and wear risks, and practicality in the given envelope.
* Concept-level parametric CAD (native format plus STEP AP214/AP242) for all parts and the assembly.
* Two to three key views or simple renders that clearly show how the mechanism works.
* High-level DFM notes and BOM suggestions using off-the-shelf components where possible (one-way clutch, rotary damper, O-rings, springs, etc.).
* A brief prototype and test plan outline describing how you would build and test a V1 prototype (suggested process such as CNC or 3D printing, approximate materials, and basic test steps).
If this goes well, a separate follow-on project (Phase 2) may cover detailed production drawings with full GD&T, tolerance stack-ups, refined material and finish choices, and more rigorous reliability analysis.
Key Design Targets (Concept-Level Estimates)
I understand these will be targets and assumptions at this stage, not fully validated guarantees:
* Opening feel: added torque approximately less than or equal to 0.05 N·m (near-zero drag when opening).
* Damping zone: roughly 20° down to 5° before latch, with damping in the 0.15–0.25 N·m range mid-stroke.
* Engagement: mechanism engages around 15° ± 5° before full close.
* Close time: approximately 2–4 seconds from around 20° to shut.
* Durability goal: ultimately aiming for about 50,000 cycles and no visible leaks at 40 °C for 30 minutes. You can treat these as design goals and comment on feasibility and risks at concept stage.
I will provide additional notes on door weight and typical use if needed.
Interfaces and Envelope
The mechanism should work as a retrofit on a typical interior residential hinge:
* Replaces the hinge pin in a standard 3-knuckle hinge.
* Typical knuckle ID: 6.35–6.45 mm (I will provide my actual measurements).
* Initial assumptions:
* Sleeve OD approximately 6.30 mm.
* Internal rotor diameter approximately 5 mm.
* Anti-rotation collar or feature to locate to the hinge leaf:
* Leaf thickness range: 2.3–3.0 mm (typical stamped hinge leaf).
* A small top module above the hinge is acceptable and expected:
* Target top module envelope: diameter up to 26 mm and height up to 25 mm from the hinge top.
If you believe a slightly different envelope (for example, a slightly larger top module) dramatically improves feasibility or reliability, I am open to your engineering recommendations.
Deliverables
* Native CAD files for the concept assembly and parts (for example, SolidWorks, Fusion 360, Inventor, etc.).
* STEP files (AP214/AP242) of all components and the assembly.
* Fully labeled PDF drawings at concept level (main dimensions and critical fits; full production drawings can be a separate project).
* A short written report (PDF or DOC) covering:
* How the mechanism works (with references to your CAD views).
* Key assumptions (door mass, speed, expected forces).
* Main risks (space constraints, wear points, leak risks, spring selection, etc.).
* BOM suggestions with candidate off-the-shelf parts where possible (for example, small one-way clutch sizes, compact rotary dampers, standard O-rings and springs), plus brief DFM comments.
* Prototype and test plan outline (recommended fabrication route, basic test setup, and what to measure).
Collaboration and Expectations
* Please share examples of past work involving small mechanisms (clutches, dampers, latches, or similar assemblies), not just exterior product styling.
* I expect one to two rounds of minor revisions based on feedback (not a full redesign), included in the fixed price.
* Any modern parametric CAD is fine as long as you can provide STEP files plus native files. SolidWorks or Fusion 360 is preferred but not required.
IP and Confidentiality
* I will provide a simple Mutual NDA and a Contractor IP Assignment or work-made-for-hire agreement (where permitted by your jurisdiction).
* All IP for this project (CAD, drawings, concepts, and documentation) will belong to me.
* You agree not to use the design, specifications, or underlying concept in your portfolio or for other clients without my written consent.
* You also agree not to use my confidential information to build or assist a directly competing soft-close hinge pin product for 12 months after completion of this project.
Please confirm in your proposal that you are:
1. Comfortable working under an NDA and IP assignment, and
2. Able to show at least one prior project involving small mechanical assemblies or mechanisms.
Looking forward to working with someone who enjoys tricky mechanism challenges and compact packaging problems. read less
The idea is a replacement hinge pin (with a small top module if needed) that uses a one-way clutch and rotary viscous damper to slow the last approximately 20° of door closing, while keeping near-zero drag on opening.
Scope (Phase 1 – Concept and Feasibility Only)
What I need in this phase:
* Feasibility review of a retrofit soft-close hinge pin / hinge-top module concept, including engage angle, torque curve, basic leak and wear risks, and practicality in the given envelope.
* Concept-level parametric CAD (native format plus STEP AP214/AP242) for all parts and the assembly.
* Two to three key views or simple renders that clearly show how the mechanism works.
* High-level DFM notes and BOM suggestions using off-the-shelf components where possible (one-way clutch, rotary damper, O-rings, springs, etc.).
* A brief prototype and test plan outline describing how you would build and test a V1 prototype (suggested process such as CNC or 3D printing, approximate materials, and basic test steps).
If this goes well, a separate follow-on project (Phase 2) may cover detailed production drawings with full GD&T, tolerance stack-ups, refined material and finish choices, and more rigorous reliability analysis.
Key Design Targets (Concept-Level Estimates)
I understand these will be targets and assumptions at this stage, not fully validated guarantees:
* Opening feel: added torque approximately less than or equal to 0.05 N·m (near-zero drag when opening).
* Damping zone: roughly 20° down to 5° before latch, with damping in the 0.15–0.25 N·m range mid-stroke.
* Engagement: mechanism engages around 15° ± 5° before full close.
* Close time: approximately 2–4 seconds from around 20° to shut.
* Durability goal: ultimately aiming for about 50,000 cycles and no visible leaks at 40 °C for 30 minutes. You can treat these as design goals and comment on feasibility and risks at concept stage.
I will provide additional notes on door weight and typical use if needed.
Interfaces and Envelope
The mechanism should work as a retrofit on a typical interior residential hinge:
* Replaces the hinge pin in a standard 3-knuckle hinge.
* Typical knuckle ID: 6.35–6.45 mm (I will provide my actual measurements).
* Initial assumptions:
* Sleeve OD approximately 6.30 mm.
* Internal rotor diameter approximately 5 mm.
* Anti-rotation collar or feature to locate to the hinge leaf:
* Leaf thickness range: 2.3–3.0 mm (typical stamped hinge leaf).
* A small top module above the hinge is acceptable and expected:
* Target top module envelope: diameter up to 26 mm and height up to 25 mm from the hinge top.
If you believe a slightly different envelope (for example, a slightly larger top module) dramatically improves feasibility or reliability, I am open to your engineering recommendations.
Deliverables
* Native CAD files for the concept assembly and parts (for example, SolidWorks, Fusion 360, Inventor, etc.).
* STEP files (AP214/AP242) of all components and the assembly.
* Fully labeled PDF drawings at concept level (main dimensions and critical fits; full production drawings can be a separate project).
* A short written report (PDF or DOC) covering:
* How the mechanism works (with references to your CAD views).
* Key assumptions (door mass, speed, expected forces).
* Main risks (space constraints, wear points, leak risks, spring selection, etc.).
* BOM suggestions with candidate off-the-shelf parts where possible (for example, small one-way clutch sizes, compact rotary dampers, standard O-rings and springs), plus brief DFM comments.
* Prototype and test plan outline (recommended fabrication route, basic test setup, and what to measure).
Collaboration and Expectations
* Please share examples of past work involving small mechanisms (clutches, dampers, latches, or similar assemblies), not just exterior product styling.
* I expect one to two rounds of minor revisions based on feedback (not a full redesign), included in the fixed price.
* Any modern parametric CAD is fine as long as you can provide STEP files plus native files. SolidWorks or Fusion 360 is preferred but not required.
IP and Confidentiality
* I will provide a simple Mutual NDA and a Contractor IP Assignment or work-made-for-hire agreement (where permitted by your jurisdiction).
* All IP for this project (CAD, drawings, concepts, and documentation) will belong to me.
* You agree not to use the design, specifications, or underlying concept in your portfolio or for other clients without my written consent.
* You also agree not to use my confidential information to build or assist a directly competing soft-close hinge pin product for 12 months after completion of this project.
Please confirm in your proposal that you are:
1. Comfortable working under an NDA and IP assignment, and
2. Able to show at least one prior project involving small mechanical assemblies or mechanisms.
Looking forward to working with someone who enjoys tricky mechanism challenges and compact packaging problems. read less
I’m looking for an experienced mechanical engineer to help with Phase 1: concept and feasibility for a retrofit soft-close mechanism for a residential door hinge.
The idea is a replacement hinge pin (with a small top module if needed) that uses a one-way clutch and rotary viscous damper to slow the last approximately 20° of door closing, while keeping near-zero drag on opening.
Scope (Phase... read more
The idea is a replacement hinge pin (with a small top module if needed) that uses a one-way clutch and rotary viscous damper to slow the last approximately 20° of door closing, while keeping near-zero drag on opening.
Scope (Phase... read more
I’m looking for an experienced mechanical engineer to help with Phase 1: concept and feasibility for a retrofit soft-close mechanism for a residential door hinge.
The idea is a replacement hinge pin (with a small top module if needed) that uses a one-way clutch and rotary viscous damper to slow the last approximately 20° of door closing, while keeping near-zero drag on opening.
Scope (Phase 1 – Concept and Feasibility Only)
What I need in this phase:
* Feasibility review of a retrofit soft-close hinge pin / hinge-top module concept, including engage angle, torque curve, basic leak and wear risks, and practicality in the given envelope.
* Concept-level parametric CAD (native format plus STEP AP214/AP242) for all parts and the assembly.
* Two to three key views or simple renders that clearly show how the mechanism works.
* High-level DFM notes and BOM suggestions using off-the-shelf components where possible (one-way clutch, rotary damper, O-rings, springs, etc.).
* A brief prototype and test plan outline describing how you would build and test a V1 prototype (suggested process such as CNC or 3D printing, approximate materials, and basic test steps).
If this goes well, a separate follow-on project (Phase 2) may cover detailed production drawings with full GD&T, tolerance stack-ups, refined material and finish choices, and more rigorous reliability analysis.
Key Design Targets (Concept-Level Estimates)
I understand these will be targets and assumptions at this stage, not fully validated guarantees:
* Opening feel: added torque approximately less than or equal to 0.05 N·m (near-zero drag when opening).
* Damping zone: roughly 20° down to 5° before latch, with damping in the 0.15–0.25 N·m range mid-stroke.
* Engagement: mechanism engages around 15° ± 5° before full close.
* Close time: approximately 2–4 seconds from around 20° to shut.
* Durability goal: ultimately aiming for about 50,000 cycles and no visible leaks at 40 °C for 30 minutes. You can treat these as design goals and comment on feasibility and risks at concept stage.
I will provide additional notes on door weight and typical use if needed.
Interfaces and Envelope
The mechanism should work as a retrofit on a typical interior residential hinge:
* Replaces the hinge pin in a standard 3-knuckle hinge.
* Typical knuckle ID: 6.35–6.45 mm (I will provide my actual measurements).
* Initial assumptions:
* Sleeve OD approximately 6.30 mm.
* Internal rotor diameter approximately 5 mm.
* Anti-rotation collar or feature to locate to the hinge leaf:
* Leaf thickness range: 2.3–3.0 mm (typical stamped hinge leaf).
* A small top module above the hinge is acceptable and expected:
* Target top module envelope: diameter up to 26 mm and height up to 25 mm from the hinge top.
If you believe a slightly different envelope (for example, a slightly larger top module) dramatically improves feasibility or reliability, I am open to your engineering recommendations.
Deliverables
* Native CAD files for the concept assembly and parts (for example, SolidWorks, Fusion 360, Inventor, etc.).
* STEP files (AP214/AP242) of all components and the assembly.
* Fully labeled PDF drawings at concept level (main dimensions and critical fits; full production drawings can be a separate project).
* A short written report (PDF or DOC) covering:
* How the mechanism works (with references to your CAD views).
* Key assumptions (door mass, speed, expected forces).
* Main risks (space constraints, wear points, leak risks, spring selection, etc.).
* BOM suggestions with candidate off-the-shelf parts where possible (for example, small one-way clutch sizes, compact rotary dampers, standard O-rings and springs), plus brief DFM comments.
* Prototype and test plan outline (recommended fabrication route, basic test setup, and what to measure).
Collaboration and Expectations
* Please share examples of past work involving small mechanisms (clutches, dampers, latches, or similar assemblies), not just exterior product styling.
* I expect one to two rounds of minor revisions based on feedback (not a full redesign), included in the fixed price.
* Any modern parametric CAD is fine as long as you can provide STEP files plus native files. SolidWorks or Fusion 360 is preferred but not required.
IP and Confidentiality
* I will provide a simple Mutual NDA and a Contractor IP Assignment or work-made-for-hire agreement (where permitted by your jurisdiction).
* All IP for this project (CAD, drawings, concepts, and documentation) will belong to me.
* You agree not to use the design, specifications, or underlying concept in your portfolio or for other clients without my written consent.
* You also agree not to use my confidential information to build or assist a directly competing soft-close hinge pin product for 12 months after completion of this project.
Please confirm in your proposal that you are:
1. Comfortable working under an NDA and IP assignment, and
2. Able to show at least one prior project involving small mechanical assemblies or mechanisms.
Looking forward to working with someone who enjoys tricky mechanism challenges and compact packaging problems. read less
The idea is a replacement hinge pin (with a small top module if needed) that uses a one-way clutch and rotary viscous damper to slow the last approximately 20° of door closing, while keeping near-zero drag on opening.
Scope (Phase 1 – Concept and Feasibility Only)
What I need in this phase:
* Feasibility review of a retrofit soft-close hinge pin / hinge-top module concept, including engage angle, torque curve, basic leak and wear risks, and practicality in the given envelope.
* Concept-level parametric CAD (native format plus STEP AP214/AP242) for all parts and the assembly.
* Two to three key views or simple renders that clearly show how the mechanism works.
* High-level DFM notes and BOM suggestions using off-the-shelf components where possible (one-way clutch, rotary damper, O-rings, springs, etc.).
* A brief prototype and test plan outline describing how you would build and test a V1 prototype (suggested process such as CNC or 3D printing, approximate materials, and basic test steps).
If this goes well, a separate follow-on project (Phase 2) may cover detailed production drawings with full GD&T, tolerance stack-ups, refined material and finish choices, and more rigorous reliability analysis.
Key Design Targets (Concept-Level Estimates)
I understand these will be targets and assumptions at this stage, not fully validated guarantees:
* Opening feel: added torque approximately less than or equal to 0.05 N·m (near-zero drag when opening).
* Damping zone: roughly 20° down to 5° before latch, with damping in the 0.15–0.25 N·m range mid-stroke.
* Engagement: mechanism engages around 15° ± 5° before full close.
* Close time: approximately 2–4 seconds from around 20° to shut.
* Durability goal: ultimately aiming for about 50,000 cycles and no visible leaks at 40 °C for 30 minutes. You can treat these as design goals and comment on feasibility and risks at concept stage.
I will provide additional notes on door weight and typical use if needed.
Interfaces and Envelope
The mechanism should work as a retrofit on a typical interior residential hinge:
* Replaces the hinge pin in a standard 3-knuckle hinge.
* Typical knuckle ID: 6.35–6.45 mm (I will provide my actual measurements).
* Initial assumptions:
* Sleeve OD approximately 6.30 mm.
* Internal rotor diameter approximately 5 mm.
* Anti-rotation collar or feature to locate to the hinge leaf:
* Leaf thickness range: 2.3–3.0 mm (typical stamped hinge leaf).
* A small top module above the hinge is acceptable and expected:
* Target top module envelope: diameter up to 26 mm and height up to 25 mm from the hinge top.
If you believe a slightly different envelope (for example, a slightly larger top module) dramatically improves feasibility or reliability, I am open to your engineering recommendations.
Deliverables
* Native CAD files for the concept assembly and parts (for example, SolidWorks, Fusion 360, Inventor, etc.).
* STEP files (AP214/AP242) of all components and the assembly.
* Fully labeled PDF drawings at concept level (main dimensions and critical fits; full production drawings can be a separate project).
* A short written report (PDF or DOC) covering:
* How the mechanism works (with references to your CAD views).
* Key assumptions (door mass, speed, expected forces).
* Main risks (space constraints, wear points, leak risks, spring selection, etc.).
* BOM suggestions with candidate off-the-shelf parts where possible (for example, small one-way clutch sizes, compact rotary dampers, standard O-rings and springs), plus brief DFM comments.
* Prototype and test plan outline (recommended fabrication route, basic test setup, and what to measure).
Collaboration and Expectations
* Please share examples of past work involving small mechanisms (clutches, dampers, latches, or similar assemblies), not just exterior product styling.
* I expect one to two rounds of minor revisions based on feedback (not a full redesign), included in the fixed price.
* Any modern parametric CAD is fine as long as you can provide STEP files plus native files. SolidWorks or Fusion 360 is preferred but not required.
IP and Confidentiality
* I will provide a simple Mutual NDA and a Contractor IP Assignment or work-made-for-hire agreement (where permitted by your jurisdiction).
* All IP for this project (CAD, drawings, concepts, and documentation) will belong to me.
* You agree not to use the design, specifications, or underlying concept in your portfolio or for other clients without my written consent.
* You also agree not to use my confidential information to build or assist a directly competing soft-close hinge pin product for 12 months after completion of this project.
Please confirm in your proposal that you are:
1. Comfortable working under an NDA and IP assignment, and
2. Able to show at least one prior project involving small mechanical assemblies or mechanisms.
Looking forward to working with someone who enjoys tricky mechanism challenges and compact packaging problems. read less
Things to know
Expert
Skill Level
$500
Fixed-rate (USD)
Part-time
Job type
Under 1-month
Job duration
Areas of expertise
3D Model & 2D Drawings
Assembly Drawings
Autodesk Fusion 360
Autodesk Inventor
CATIA
Machine Design
Mechanical Design
Mechanical Engineering
PTC CREO
Prototype Design
Sheet Metal
Solidworks
+9 more
Job categories
Mechanical CAD Design
Mechanical Engineering
Mechanical Design Services
Mechanical Drafting
3D Modeling
+2 more
About the client
Payment ready
United States (11:21 pm)
Posted
Active
Job activity
33 Applicants
1 interviews in progress
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