: These parts are often part of a larger "Dolly Kit" (such as Kit 22) used for maintaining pump head rings or plunger seals. 2. Heavy Transport & Trailer Equipment

: Popularized by Spike Lee in the late 1980s, this technique involved mounting both the camera and the actor on a dolly. 4. Other Historical Contexts Dolly Set Maintenance Manual | PDF | Vehicles - Scribd

In the 1980s and early trailers, "dolly" refers to the unpowered vehicle used to support a semi-trailer.

: For military or heavy-duty vintage dollies, the Dolly Set Maintenance Manual provides detailed PDF instructions on air reservoir draincocks, brake shoe handling (warning of asbestos in older models), and hub rotation.

If you are looking for a camera dolly guide, "22" often refers to the track width or a specific model version.

: Modern versions like the TAD 22 are designed for two-axle semi-trailers, but they follow the mechanical principles established by older 1980s-era transport dollies. 3. Film & Production Equipment