ZP 01.646 Safety Shear Pin

ZP 01.646 Safety Shear Pin for Grain Thrower Reverse Gear

The ZP 01.646 safety shear pin is a compact yet essential running gear component utilized in the ZP 01.220 reverse gear mechanism of classic ZM-60, ZM-60A grain throwers, and their modifications. The element is installed within the reverse drive half-axle assembly and serves as the connecting link between the ZP 01.625 shaft and the ZP 01.340 drive sprocket.

The primary purpose of this pin is to act as a "weak link" (shear safety fuse) within the machine's power transmission. During grain thrower operations across the threshing floor, the pin secures the sprocket to the shaft and ensures torque transmission from the self-propelled gearbox to the driving wheel. However, in the event of critical overloads, wheel jamming, or heavy obstructions encountered under the wheels, the pin is engineered to shear first—allowing the kinematic connection to break rapidly and protecting the expensive self-propelled gearbox, drive chains, and transmission components from catastrophic damage.

Technical Specifications of the ZP 01.646 Pin

• Catalog number: ZP 01.646
• Application: ZM-60, ZM-60A
• Installation assembly: Rear drive ZP 01.220 (securing sprocket ZP 01.340 onto shaft ZP 01.625)
• Purpose: Emergency protection of the self-propelled transmission from destructive overloads
• Material: Structural carbon steel (Steel 35)
• Part weight: 0.019 kg
• Quantity per assembly: 1 pc. (on asymmetric drives) or 2 pcs. (on symmetric modifications)

The solid cylindrical form with a precise calibrated diameter is manufactured from structural steel with strictly calculated shear strength thresholds. The pin is easily installed into the bore of the ZP 01.625 shaft through the hub of the ZP 01.340 drive sprocket, while its axial retention against sliding out from vibrations is further guaranteed by an adjacent retaining ring.

Operational experience and field modifications show that the factory design utilizing a pin that absorbs all peak loads frequently draws complaints from equipment operators due to frequent work stoppages during intensive operations. Seeking to improve operational continuity, farms often abandon the standard "soft" pin—replacing it with hardened steel dowels, milling custom keyways, or applying heavy-duty fasteners. While this makes the assembly significantly more resistant to loads, it strips the grain thrower of its guaranteed emergency protection, meaning that during an unexpected jam, the entire destructive force transfers directly onto the teeth of the self-propelled gearbox gears.

Associated Spare Parts and Interconnection in the Running Gear Assembly

Within the grain thrower's running gear, the ZP 01.646 safety pin functions within a strictly defined kinematic pairing. Related components include:

• Reverse shaft ZP 01.625
• Drive sprocket ZP 01.340 (Z=25, t=19.05 mm)
• Thrust retaining rings (6511 019 GOST 2833-77) — 2 pcs.
• Drive chain PRL-19.05 — reverse roller chain

Any alterations to the pin parameters or sprocket seating directly impact adjacent elements—if the pin hole in the shaft or sprocket elongates due to prolonged operation with play, simply installing a new pin will not provide a tight fit. In such cases, a comprehensive inspection of the seating surfaces or adaptation of adjacent parts to new parameters is required.

Buying the ZP 01.646 Safety Pin and Other Components from Zavod Moroza

Despite the negligible cost of this part, having a high-quality and correctly engineered safety pin is the cornerstone of preserving the expensive transmission of a classic grain thrower. The ZP 01.646 pins manufactured at Zavod Moroza strictly comply with original technological requirements and GOST standards, withstanding rated operational forces while guaranteed to shear only under dangerous overloads.

We manufacture both standard serial pins for spare parts kits and routine maintenance, and offer calculated engineering solutions for restored or modified half-axles. If your shafts or sprockets have already undergone modifications, the specialists at Zavod Moroza will help select matching repair pins, keys, or supply fully pre-assembled turnkey reverse drive units. Choose reliable components directly from the manufacturer for the safe and long-lasting operation of your agricultural machinery!