When a machine is operated on tires, the machine capacities are different from a machine that is operated on stabilizers. Also, the machine capacities for each type of attachment are different.
Machine instability can result in injury or death. To ensure stability during operation the following conditions must be observed: Tires must be correctly inflated and have the correct amount of ballast (if equipped). The machine frame must be level. The frame level switch must never be operated when the boom is raised. The frame level switch must never be operated when stabilizers are lowered. Stabilizer switches must never be operated when the boom is raised. The correct load chart for the machine as equipped must be referenced and the weights and load centers specified must never be exceeded. The machine must never be moved when the boom is raised. |
Illustration 1 | g00955167 |
The load charts are located on the dash panel at the right side of the instrument cluster. Ensure that the correct load chart is used. The chart is intended for the type of attachment that is represented by a symbol at the top of the chart. Symbols are also shown for operation on tires or on stabilizers. The load charts may be in metric units (meters and kilograms) or conventional units (feet and pounds).
When the machine is operated on tires, the weight of the intended load determines the maximum height above ground. The weight of the intended load also determines the maximum distance that is between the load center of gravity and the front wheels.
When the machine is operated with lowered stabilizers, the weight of the intended load determines the maximum height above ground. The weight of the intended load also determines the maximum distance that is between the load center of gravity and the stabilizer pads.
The machine boom has two scales which must be used for reference with the load chart in order to assess the lift operation. The boom extension reference scale gives an indication of the boom length. The letters "B", "C" and "D" correspond to the same letters on the load chart. The letter "A" on the load chart corresponds to the fully retracted position of the boom. The letter "E" on the load chart corresponds to the fully extended position of the boom.
Illustration 2 | g00955168 |
Boom angle reference scale (1) gives an indication of the angle of the boom.
Follow the instructions below in order to assess the intended load:
- Carefully position the machine. The machine should be as close as possible to the intended load. For more information on operating the machine, refer to the appropriate topic in the Operation Section of the Operation and Maintenance Manual.
- In order to move the attachment into position for the operation, raise the boom and extend the boom, as required. Do not make the lift operation.
- Look at the boom extension reference scale and the boom angle reference scale and note the readings. Refer to the load chart and use these two values in order to locate the equivalent load zone.
- If the intended load is equal to the value in the equivalent load zone the lift operation can be attempted with caution. Also, if the intended load is less than the value in the equivalent load zone the lift operation can be attempted with caution.
- If the intended load is heavier than the value in the equivalent load zone the lift operation cannot be made.
Examples of Estimating the Lift Operation from the Load Chart
Note: In the examples that follow, the numbers are from the load chart that is shown at the end of this section. This load chart is only for illustrative purposes. This load chart does not relate to any particular machine. The numbers that are quoted have no units. The units on the load charts which are installed in a particular machine may be kilograms or pounds.
Example 1
- The weight of the intended load is 45 units.
- The boom angle reference is 56 degrees.
- The boom extension reference scale is at "D".
With reference to the load chart, "X" is the point of intersection for the values of the boom angle reference and the boom extension reference. This point of intersection is in the load zone for 80 units. The intended load of 45 units is less than the value in the load zone so the load chart indicates that the load is within the capacity of the machine.
Example 2
- The weight of the intended load is 125 units.
- The boom angle reference is 40 degrees.
- The boom extension reference scale is at "B".
With reference to the load chart, "Y" is the point of intersection for the values of the boom angle reference and the boom extension reference. This point of intersection is in the load zone for 125 units. The intended load of 125 units is the same value as the value in the load zone so the load chart indicates that the load is at the maximum capacity of the machine.
Example 3
- The weight of the intended load is 27 units.
- The boom angle reference is 22 degrees.
- The boom extension reference scale is approximately 66 percent between "D" and full extension. Full extension is "E" on the load chart.
With reference to the load chart, "Z" is the point of intersection for the values of the boom angle reference and the boom extension reference. This point of intersection is in the load zone for 20 units. The intended load of 27 units is greater than the value in the load zone so the load chart indicates that the load is beyond the capacity of the machine. The lift operation must not be attempted.
If the load chart indicates that the lift operation is within the capacity of the machine, attempt to make the operation but proceed with care. Remember that the load may weigh more than the estimate for the load. The load chart is for estimating the lift operation only.
Illustration 3 | g00992051 |
Typical Load Chart |