Cylinder Selection

BC4 Band Cylinder Selection Procedure
1.  Compile Application Requirements
To determine the appropriate BC4 actuator for an application, compile the following information:
  • Available pressure (PSI)
  • Weight of load (lbs. or kgs.)
  • Orientation of load (lbs. or kgs.)
  • Velocity of load (in./sec. or mm/sec.)
  • Stroke length (in. or mm)
2.  Select Cylinder Size
  • Consult the Theoretical Force vs. Pressure charts
  • Cross reference the load force (or load weight if force is not known) and the available operating pressure. If the intersection falls below the diagonal line, and if moments do not exceed maximum values listed for that model (see Step 3), the actuator will accommodate the application. If the intersection is above the diagonal line, a larger cylinder bore size should be considered.
NOTE: Additional force may be required to obtain the necessary acceleration for vertical or horizontal loads.

3.  Determine Nature of Load and the Effect of Bending Moments
If the cylinder will guide and support a load located directly over the center of carrier, bending moments will not be a factor in the cylinder selection. NOTE: The maximum load "L" must not exceed the capacity limits of the cylinder selected.

  • Bending Moments
    For off center or side loads, determine the distance from the center of mass of the load to the center of the carrier bracket. This measurement is needed to calculate the torque for bending moments. Should the resulting maximum bending moment exceed figures indicated on the chart, external guides, auxiliary carriers or a larger cylinder should be considered.
  • Auxiliary Carrier Bending Moments
    The auxiliary carrier option increases load carrying capacity and bending moments. Auxiliary carriers for BC4 actuators can only be ordered with an internal piston.

    Important: When ordering, determine the working stroke, then the minimum distance required between carriers (dimension "D" in Auxiliary Carrier Bending Moments chart). When ordered, Tolomatic's configurator will calculate the overall length of the actuator.

    NOTE: breakaway pressure will increase when using auxiliary carriers.
4.  Determine Internal Cushion Capacity
  • Consult the Cushion Data chart for the model selected. The velocities listed on the cushion charts are final or cushion impact velocities. On applications where the internal cushions or bumpers are to be used, be sure the actual, final or impact velocity is known. If the velocity is not known, use of limit switches with valve deceleration circuits or shock absorbers should be considered.
  • Cross-reference the final velocity and weight of the load. If the intersection is below the diagonal lines the internal cushions on the actuator may be used. If the point falls above the dashed diagonal line or if the velocity is not known, use deceleration circuits, external shock absorbers or select a larger cylinder with greater cushion capacity. On high-cyclic applications, use of external stops is strongly recommended.

5. Determine Tube Support Requirements

  • Consult the Tube Support chart for the model selected.
  • Cross reference the load weight and maximum distance between supports.
6.  Consider Options
  • Switches- dc Reed, Hall-effect or ac Triac
  • Shock Absorbers- if needed
  • Foot Mounts
  • Floating Mounts
  • Tube Supports