Physical Address
304 North Cardinal St.
Dorchester Center, MA 02124
Application of Hydraulic Remote Control to Agricultural Tractors and Trailing Type Agricultural Implements
Overview and Scope
This SAE Standard (J716) provides specifications and dimensions for hydraulic cylinders used with trailing-type farm implements. It ensures interchangeability between tractors equipped with a hydraulic cylinder and various implements, provided the tractor has sufficient drawbar power. The standard defines three categories of agricultural tractors based on maximum drawbar power:
| Category | Maximum Drawbar Power |
|---|---|
| 1 | Up to 35 kW |
| 2 | 30 to 75 kW |
| 3 | Over 70 kW |
This standard is an English translation of ISO 2057 (1981) with modifications indicated by double asterisks. It references related SAE standards for three-point hitches (J715), PTO drives (J717), and rear PTO (J1170).
Dimensional Specifications for Cylinders and Yokes
Interchangeability hinges on adhering to precise clearance measurements. The standard specifies two stroke lengths: 200 mm and 400 mm. Key cylinder clearances are summarized in the table below.
| Dimension | Description | 200 mm Stroke (mm) | 400 mm Stroke (mm) |
|---|---|---|---|
| a | Between pin centerlines (extended) | 721 | 1210 |
| b | Between pin centerlines (retracted) | 514 | 800 |
| c | Overall length (extended) | 785 | 1280 |
| n | Cylinder outside diameter | 127 | 152 |
| Pin nominal diameter | Yoke pin size | 25.0 | 31.75 |
🛠️ Design Insight: Exact conformance to these dimensions is critical. The yoke clearances, pin diameters, and throat radii must match standard values to allow cylinders from different manufacturers to be used interchangeably. Note that the 400 mm stroke cylinder uses a larger nominal pin diameter (31.75 mm) compared to the 200 mm stroke (25.0 mm).
Note: Double asterisks (**) in the original standard denote items that deviate from ISO 2057. When designing for international compatibility, pay special attention to these divergences.
Application Guidelines and Common Pitfalls
Successful hydraulic operation requires careful consideration of thrust, hose routing, and operating characteristics. The minimum thrust capacity for the extending stroke is based on the piston area and 80% of the relief valve setting. Implements requiring over 80 kN thrust must use a 400 mm stroke cylinder.
Key operational specifications:
- Hose length: Must allow full cylinder travel and, for three-point hitched implements, an additional 100 mm rearward movement of the implement relative to the tractor.
- Operating time: Extending stroke at maximum engine speed should be 1.5–2.5 seconds for categories 1 and 2, and 3–4 seconds for category 3.
- Variable stroke control: Applied to the retracting stroke; the implement must accommodate the fully extended moving end.
- Both single- and double-acting cylinders must raise the implement on the extending stroke.
⚠️ Common Mistakes:
- Using a 25.0 mm pin on a 400 mm stroke cylinder instead of the required 31.75 mm pin.
- Calculating thrust based on full relief valve pressure instead of 80% of that value.
- Not providing enough hose slack when using a three-point linkage — always allow 100 mm rearward movement.
- Overlooking the spherical radius limitation for the front attaching pin when using three-point hitches.
🔍 Engineering Reminder: Always verify that the attaching pins are easily removable and that hose supports are considered part of the implement to avoid interference with moving parts.
Frequently Asked Questions
1. What are the three categories of agricultural tractors defined in SAE J716?
The categories are based on maximum drawbar power: Category 1 (up to 35 kW), Category 2 (30 to 75 kW), and Category 3 (over 70 kW). Note there is overlap between categories 2 and 3.
2. How is the minimum thrust capacity of a hydraulic cylinder determined?
Thrust is calculated using the effective piston area multiplied by 80% of the hydraulic system’s relief valve setting. This ensures a safety margin and consistent operation across varying pressures.
3. What are the standard stroke lengths and when should each be used?
Two strokes are standardized: 200 mm and 400 mm. The 200 mm stroke is common for most implements. The 400 mm stroke is required when the implement demands a cylinder thrust of more than 80 kN, as specified in Section 4 of the standard.
4. Can a cylinder from one tractor category be used on a different category?
Interchangeability is assured within the same tractor category provided the dimensional specifications match. For cross-category applications, the tractor must have adequate drawbar power, and dimensions may need to be verified against the standard. However, the standard primarily aims at compatibility within each category.
