Ralphs-Pugh plastic rollers are available in a wide range of bearings, tube, and shaft combinations. Plastic rollers are ideal for light duty gravity applications, humid, corrosive or wet environments. Typical applications include; food processing, chemical or acidic environments, battery handling, and package handling. The following information is provided to help match the operating environment with the proper product.

Roller Selection Criteria:

To select the right roller for the operating environment, the following items must be considered:

• Conveyed Items or Materials.
  Size / Shape / Weight
• Surface Characteristics of Materials
• Operating Environment
  Heat / Humidity
  Exposure to Chemicals

Materials:

Tubes:

• Standard Gray PVC
• "Hi-Impact" White PVC with UV Stabilizers
• Polyproplene
• Steel Reinforced PVC

Drive options:

• Grooves
• V-Guides

Shaft Configuration & Materials:

• Hex, Round - Dual spring loading is standard - Option: Fixed or Loose
• Carbon Steel, Stainless Steel, Aluminum
• Zinc and Nickel Plating Available

Shaft Extensions:

• 9/16” is standard for 3/16“ round to 1/2” round or 7/16“ hex
• 3/4” is standard for 5/8“ - 11/16” round or hex and larger
• Measurements are from the hub of the bearing to the end of the shaft on each side.

Shaft End Options:

• Drilled and Tapped, Threaded, Drilled Holes, Milled Flats
• Plastic Flat Caps, Urethane & Plastic Adapters over an internal metal support shaft

Bearings & Bushings:

Commercial Grade / Non Precision

Ball bearings in a plastic raceway:

Economical light duty stainless steel balls in engineered plastic raceways. These bearings are ideal for wet environments where corrosion is a concern. They are free spinning and maintenance free. All plastic raceways are designed, engineered, and molded in our facility. Standard ball materials are 302 or 316 series stainless steel. Applications include food processing, clean rooms, packaging machinery, and general material handling. These bearings are identified by a 1 in the prefix of the part number. These bearings are not recommended for powered applications. Example - 1A5

Plated Steel / Plastic Housings

Designed for light to moderate loads, these commercial grade ball bearings have hardened steel balls and machined inner and outer raceways. They are available with light oil or grease lubricant for driven systems. Plastic housings are available in conductive or non-conductive material with or without labyrinth seals. The labyrinth seal(s) provide protection to the bearing from dust, dirt, and airborne contaminants. These bearings are identified by a 2 in the prefix of the part number. Example - 2A4

Stainless Steel / Plastic Housings

Designed for light to moderate loads, commercial grade stainless steel balls and raceways provide an excellent solution for corrosive operating environments. For maximum protection against contamination, some housings are available with labyrinth seal systems. Example - 2A5

Precision Grade / ABEC-1

Designed for higher speeds and heavier loads, ABEC-1 precision bearings are available in chromium steel and optional 440, 304 or 316 stainless steel. ABEC-1 ball bearings and raceways are hardened, precision ground, and incorporate a ball retainer to eliminate bearing to bearing contact. Bearings are factory lubricated. Several seal/shield configurations are offered. Standard configuration is the Non-Contact Rubber Seal (LLB). Options include; the Contact Seal (2RS) and Non-Contact Metal Shields (ZZ). Bearing housings are available in metal or plastic. Plastic housings are made with conductive or non-conductive materials and available with or without labyrinth seals. Labyrinth seals provide additional bearing protection against dirt, dust, and other airborne contaminants. ABEC-1 bearings provide the highest load and speed capabilities, the lowest noise levels, and the longest life span of any available bearing unit. These bearings are identified by a 3 in the prefix of the part number. Example - 3A4

Bushings

Non ball bearing style units are designed for low speed, light to medium load applications. Bushing surface materials include; Ultra (Acetal plastic with Teflon Additives), CS2 Acetal, UHMW, and ABS plastic. Bushing insert materials include nylon, stainless steel, carbon steel and Ultra. Bushing style rollers are ideal for sanitary, rust and corrosion resistance applications in push and gravity conveyors. These bearings are identified by a 5 in the prefix of the part number. Example - 5A8

Load Capacities

Load capacities listed are based upon length of the roller (IF), actual load ratings for the bearing, tube deflection and shaft deflection for the materials listed. Calculations for load capacities of precision bearings allow for ¾ of 1 degree of shaft deflection while commercial bearings allow for 1 degree of shaft deflection. Shaft deflection will increase as a roller becomes longer and roller loads will decrease substantially as the length of the roller increases. Please note that load capacities listed are for steel shafts. Load ratings for rollers with aluminum shafts must be reduced to 33% of the value listed.

Roller Length

I.F. = Inside Frame distance. This measurement allows 1/16” of freeplay per side for a total of 1/8” per roller. O.A. = Overall Roller Length. This is the measurement from bearing hub to bearing hub of the roller. For calculation purposes I.F. - 1/8” = O.A.

Ordering Information

Ralphs-Pugh roller numbering system lists the bearing part number first, the tube part number second and the shaft part number last followed by the roller length.

Example 1: Standard Roller

Bearing: ABEC –1 precision bearing in a plastic housing – Double labyrinth seals
Tube: 1.90” outside diameter x .112” wall thickness Hi-Impact PVC tube
Shaft: 7/16” hexagonal carbon steel spring-loaded shaft with 9/16” shaft extensions
Length: Must fit a frame measuring 18” inside frame distance (I.F.)
Max. Load: Roller must be capable of handling a load of 50 lbs. per roller

Solution:

Find the plastic roller page designating 1.90” x .112” – 7/16” Hex - Use the drop down menu in the top right of this page

Bearing part #: 3A4
Tube part #: H41
Shaft part #: C68
Load per roller: Load capacity chart indicates roller is good up to 83 lbs per roller

Roller Part #: 3A4.H41.C68 x 18" I.F.

Example 2: Rollers with Options – (Grooves, Special Shaft Lengths or Extensions, etc.)

Solution:

Check Engineering Data section for specific data, information, or drawings. Inquire with Customer Service.

For a specific roller configuration, CLICK HERE.

Contact Customer Service for a detailed catalog
of Ralphs-Pugh products, 1-800-486-0021