The Hydraulic shear must be sized properly for the work it will need to do and the carrier it will be mounted to.
Based on Type of Work:
This is the most important item to consider when sizing a shear–what it will need to do!
Consideration must be given to the duty cycle. With continuous operation, it would be recommended to go up one size above the selected model. This will provide a long-term benefit of lower maintenance and higher productivity. Applications where the shear will only be operated part of the time can be sized according to the material it will need to process.
Based on Carrier Size:
The carrier that is selected to operate the shear must have the necessary oil flow and lift capacity to safely handle the attachment plus any material that may be held in the jaw. BTI has assigned a recommended Carrier Weight range for 2nd and 3rd member installation for each shear. If the operating weight of the carrier falls within this range, the carrier will safely handle this model. If the desired shear falls outside of this recommended carrier weight range, the carrier’s lifting capacity and oil flow will need to be verified to ensure a proper fit.
The maximum lifting capacity of the carrier at any position must be equal to or greater than 1.3 times the weight of the Shear. Please consult the lifting specification of the excavator for third member information and consult the manufacturer for lifting capacity for second member installations. The maximum lifting capacity is usually at the lowest when the boom is at full reach. This is the value that must be compared to the operating weight of the shear.
A required oil flow range is specified for each shear. Oil flow within this range is adequate for operation. However, for maximum cycle time the carrier should be capable of providing the maximum required flow. Compare the maximum oil flow requirement of the shear with the oil flow capacity of the carrier. It may be necessary to combine the flow from two pumps in order to provide the required amount. Remember each shear will require an additional low flow circuit to operate the hydraulic rotation motor.
Carrier Weight Range:
Find the carrier weight at the top of the chart. Follow this line down to intersect with the suggested carrier weight range for each shear model (gray bars). If the operating weight of the carrier falls within this range, the carrier will safely handle this model.
The shear can be installed as a second member by replacing the outer stick boom, or as a third member by replacing the bucket.