Tension Gas Spring
Pull Gas Spring / Reverse Action Gas Spring - Professional Industrial Solutions
1. Product Definition
Key Characteristics
Product Name: Tension Gas Spring / Pull Gas Spring / Reverse Action Gas Spring
Free State: The piston rod is in the "retracted" position
Working Characteristic: Extends when pulled, automatically retracts when released
Main Function
To enable covers/hatches that "need to be pulled down and retracted" to close automatically, while providing a controlled retraction speed. Typical applications include:
- Automatic retraction of hoods and hatches
- Assistance for medical equipment lifting
- Automatic barrier retraction
- Industrial equipment cover control
2. Structural Classification and Performance Differences
| Type | Single Tube | Double Tube |
|---|---|---|
| Rebound Speed | Fast | Slower, more stable |
| Force Progression Rate | High (100 N → 170-180 N) | Low (100 N → ~150 N) |
| Closed Length Advantage | Shorter (L ≥ 2S + 45) | Longer (L ≥ 2S + 70) |
| Applicability | Tight spaces, acceptable force progression | Stable force, high safety guidance requirements |
Single Tube Structure
- Simple design, lower cost
- Shorter closed length
- Fast rebound speed
- Noticeable force progression
- Preferred for tight space applications
Double Tube Structure
- Stable force curve
- Controllable rebound speed
- Good safety guidance
- Approx. 30% higher cost
- Preferred for high safety requirement applications
3. Core Parameter Range
Force Range
100 – 1,500 N
Common Stock: 150 / 250 / 350 N
Stroke Range
100 – 300 mm
Available in 25 mm increments
Closed Length
200 – 450 mm
Limited by formula
Minimum Order Qty
200 units
Typical Annual Volume: 500 – 5,000 units
End Fitting Configuration
Threaded Ends: Single/Double end M8 or M10 threads
Ball Joint Ends: Ø10 mm ball joint
Safety Accessories: Must be equipped with "anti-detachment pin" or safety wire
4. Working Principle - Two Modes of Operation
Mode A: Traction Gas Spring (With Pull Force)
Operation Flow
- Opening Phase: Cover's gravity overcomes initial pull force, pulling the rod out → Cover descends
- Closing Phase: Gas spring automatically retracts, assisting the cover to pull back up
Applicable Scenarios: Where the cover's natural descent is sufficient to pull the spring
Mode B: Pure Damper (Damping Only, No Pull Force)
Operation Flow
- Opening Phase: Manual push throughout, no assistance
- Closing Phase: Provides one-way damping only, allowing the cover to descend slowly
Applicable Scenarios: Light covers or safety-critical scenarios requiring "no assistance + slow descent"
Working Principle Illustration
Basic Principle: High-pressure nitrogen gas within the sealed cylinder generates a reverse thrust when the piston rod is pulled. When the external force is released, the gas pressure pushes the piston rod to retract, achieving the automatic closing function.
Key Advantage: Compared to traditional springs, gas springs offer a more stable force curve and longer service life (typically over 100,000 cycles).
5. Quick Selection Formula
Closed Length Calculation
Single Tube: L ≥ 2S + 45
Double Tube: L ≥ 2S + 70
Where: L = Closed Length (mm) | S = Working Stroke (mm)
Selection Steps
- Determine Working Stroke S: Based on the required opening range of the cover/hatch
- Select Structure Type: Choose Single or Double Tube based on space and force stability requirements
- Calculate Closed Length: Use the formula above to determine the minimum closed length
- Determine Force: Select appropriate force based on cover weight and pull resistance
- Confirm End Fitting: Choose threaded or ball joint, and configure anti-detachment pin
💡 Selection Tip: If unsure about specific parameters, we recommend starting with common stock items (150 N / 200 mm Stroke / Single Tube) for quick sample verification.