Hydraulic Brake Treadle

The customer was using a Solid Pin to connect the push rod and the pedal in the brake treadle application. The component is a pedal attached to a spring actuating mechanism assembly. The pedal is connected to the treadle in two locations. One location is a hinge between the pedal and the base. The other connection is between the pedal and the push rod. The push rod actuates the spring assembly by way of pedal movement. The Solid Pin is installed through holes in the aluminum casting and through a hole in the push rod. The Solid Pin presently has two clips that are installed into grooves in each end of the Solid Pin. The clips hold the free fitting pin in place and prevent the pin from falling out of the hole. The hole in the push rod also has a pressed-in bearing. The bearing is an oil-lite brass bearing and is used for galvanic corrosion resistance purposes.

The customer was interested in SPIROL providing a cost savings in this application. The customer was open to any changes to the application.
app coiled pin hydraulic break treadle
SPIROL Engineers determined that the closest standard diameter hole size for this application was 6mm. This diameter allowed the use of a light duty, zinc plated high carbon steel Coiled Pin. The zinc plate satisfied the galvanic corrosion requirement.

Item #53058 CLDP 6 x 28 LBT provided the customer with a substantial cost savings. The Coiled Pin is self-retaining; therefore no clips or secondary operations are required to retain it in the hole. Also, the zinc plated Coiled Pin eliminated the need for the bearing. The hole size in the push rod could be opened up because they no longer needed to install a precision bearing that requires tight tolerances.


In conclusion, the Coiled Pin required a minor hole change (in order accommodate a standard diameter pin), the Coiled Pin was 73% less expensive than the current Solid Pin with clips, and the customer reduced components by eliminating the clips and the bearing.

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SPIROL offers complimentary Application Engineering support. We will assist on new designs as well as help resolve issues, and recommend cost savings on existing designs.