HOW TO SPECIFY BERTROL® ASSEMBLIES
The type and size of conduit as well as the selection of the proper conduit fittings and length of core will be determined by your application. Once a design is selected, specify the minimum pull-off requirement of the core fitting and working load to determine core size. If the number of degrees of bend of your assembly, as installed exceeds 90°, contact Bergen Cable for design and application assistance.
Minimum Bend Radius – 7.0 inches
Minimum Bend Radius – 8.0 inches
HOW TO SPECIFY PUSH-PULL CONTROL ASSEMBLIES
This format is provided for ease of specifying and ordering your Bertrol® Push-Pull Control Assemblies.
First, determine the input load required using the Friction Loss Chart. Given the load and the travel required, determine the Bertrol® design appropriate to meet your needs. Complete the assembly part number using the format below.
Explanation of Example: SS-725-825-2-060
This order number specifies a cable with stainless steel terminals and core, a bulkhead fitting on one end and a clamp fitting on the other end, 2 inches cable travel, 60 inches in length. This order number is for a cable with a maximum input load of 50 pounds and a minimum bend radius of 6 inches.
PUSH-PULL PANEL CONTROLS
Panel push-pull controls are intended for applications with maximum input loads of 50 pounds. They are used for throttle control, choke, fuel shutoff and engine stop, as well as for power-take-off control and latches with light actuation loads.
Series 55 controls will meet applications requiring up to 20 pounds input.
Series 75 controls are for heavier input loads up to 50 pounds. The standard end types as shown for Series are not recommended for Series 75.
PANEL PUSH-PULL KNOBS
Most applications utilize one of the knob types listed below. Stocked by Bergen, these knobs are made of durable molded plastics and are compatible with both Series 55 and Series 75 Push-Pull Panel Control Assemblies.
Explanation of Example: PP-293-P75-3-058
This order number specifies a Panel push-pull cable with a “T” type knob, a Series 75 design with 3 inches of travel and 58 inch cable length.
The selection of the proper push-pull control for any application is generally a function of the input force required. This force, in turn, is dependent on the output load and the efficiency of the assembly. Friction between the inner core member and the primary tube will have the greatest impact on the assembly efficiency. As seen in the chart below, the friction factor will be dependent upon the total degrees of bend in the system.
FRICTION LOSS CHART (EFFICIENCY)
How to use chart: Determine working load and total degrees of bend in the system. Locate your degree figure on horizontal scale. Read up to intersection of curve. Locate input load factor by working load which is your calculated input load. Do not exceed the maximum input load listed under conduit data.
Bending of the conduit produces frictional losses which are proportional to the total degrees of bend in the system. In order to keep these losses to a minimum Bergen can use a special lubricant on the conduit and core members. This also increases the life of the assembly because it reduces core and conduit liner wear.
Bergen Cable Technology, LLC