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Interchangeability between the SQ standard and other brands of fully hydraulic Quick Couplers and work tools

SQ is a high performing fully automatic oil connection technology used in quick couplers and tiltrotators on excavators to connect hydraulic work tools. It has a superior performance and a robust design.

When using SQ in combination with Quick Couplers or Work Tools from other manufacturers it is important to ensure full functionality. The checklist below can help you.

Once you have checked the interchangeability and verified functionality as described, then Steelwrist approves to combine our Quick Coupler and Work Tools with its counterparts from other manufacturers. As long as our products are used in accordance with their operator manuals, Steelwrist CE marking is not affected and no additional risks are foreseen to arise due to the combined use.

1. Check the interchangeability

a. Ensure that the Work Tool adapter have the same configuration of hydraulic oil quick couplings as the Quick Coupler. Check that the size and position of all couplings are the same in both H-cylinder and coupling ramp.

b. Ensure that the pins in the adapter of the work tool conforms to the S-standard dimensions (Symmetrical Quick Couplers for Excavators, June 2011 edition). In case the adapter does not follow the S-standard, for instance if the front pin has a thicker center part (see picture 1), then such a work tool is not possible to pick up with an SQ Quick Coupler. Usually it is clearly visible in that the guiding fins on the side plates will prevent the Quick Coupler from engaging correctly and there is no green indication. Reference: Symmetrical Quick Couplers for Excavators (PDF). For dimensions related to SQ 70/55 and SQ 65, see table 1.

c. All SQ couplers from Steelwrist are equipped with the unique Front Pin Lock (FPL) safety function to increase safety when changing work tools. Ensure that there is enough space for the FPL function, see picture 2 and table 2. Some buckets can have a dirt protection plate that might need slight modification to enable the SQ FPL safety function to work properly.

d. If the work tool has an electrical connector the Quick Coupler must have the same type of connector as the Work Tool. It is possible to update the Quick Coupler or work tool connector to the same type if needed. Steelwrist V14 is a robust and flexible connector that fits all brands.

Two types of vertical electrical connectors can be mounted, either the traditional V90 connector with 10 poles or the more advanced V14 connector with 14 poles. If your Quick Coupler or Work Tool have two side by side V90 vertical connectors then they must be combined into one V14 connector instead.

2. Verify the functionality (on plain ground and with no people close by)

a. Gently couple the Work Tool with the Quick Coupler and verify that no mechanical interference occur. Any small interference must be fixed prior to next steps.

b. Ensure full FPL function by connecting only the front pin. Deliberately lock the Quick Coupler wedges above the rear pin and ensure that you get a green indication and that the FPL maintains the work tool when hanging in the front pin only.

c. Couple the work tool correctly in the quick coupler and verify the function of the hydraulic oil quick couplings. Check that no leakage exists and ensure full hydraulic function.

d. If the work tool has an electrical connector, verify that all electrical signals have full functionality.

NOTE: If you feel unsure in regards of the combination of brands contact your Steelwrist office and they will guide you further. Never use an unverified combination as this might lead to a safety risk.

NOTE: Always read the operator’s manual for your Work Tools and Quick Coupler prior to any use.

NOTE: If the adapter on your Work Tool has a dirt protection plate that cause interference with the SQ FPL function then Steelwrist can supply a plate that will fit your Work Tool.


Non conforming front pin

Picture 1. Example of non conforming front pin. It will not enter into the front jaw. The front pin must conform with S-standard eg. the same diameter the full length.


Basic measurements

Table 1. Basic measurements, extended S-measurements


FPL Clearance

Picture 2. FPL Clearance


FPL Clearance

Table 2. FPL Clearance