This document is a service and repair manual for Hyster forklifts, specifically covering the F004 series (S70XM, S80XM, S100XM, S80XM BCS, S100XM BCS, S120X MS, S100XM PRS models). It focuses on the masts, providing detailed descriptions and repair procedures for various mast types used in Hyster E3.50-5.50XL3 (E70-120XL3) [C098], S3.50-5.50XM (S70-120XM) [E004, F004], and H3.50-5.50XM (H70-120XM) [K005, L005] forklift models.
The primary function of the mast system is to lift and lower loads. It consists of vertical frames called weldments, which include channels, load rollers, and crossmembers. These components work together to support the mast and guide the movement of the carriage and forks. The mast can also tilt forward and backward, facilitated by tilt cylinders connected to the lift truck frame or drive axle, depending on the model.
Technical Specifications and Components:
- Weldments: The mast structure is built from weldments, which are the main vertical frames. Channels within these weldments serve as tracks for load rollers.
- Load Rollers: These rollers reduce friction between the channels as the weldments move vertically, handling significant forces during lifting and lowering operations. Shims are used to control lateral clearance.
- Strip Bearings: Installed at the top of each side of the outer weldment, these bearings maintain correct forward and backward clearance between weldments.
- Carriage: A separate section that moves on load rollers within the inner weldment. Forks or other load-handling attachments are mounted to the carriage, along with a load backrest extension.
- Sideshift Carriage: An optional feature that allows hydraulic adjustment of the lateral position of the load-handling device on the carriage.
- Lift Cylinders: Single-stage lift cylinders are used to extend and retract the weldments and raise the carriage. The number and arrangement vary by mast type.
- Lift Chains: These chains transfer force from the lift cylinders to the carriage, controlling its movement. They run over chain sheaves.
- Tilt Cylinders: These hydraulic cylinders enable the mast to tilt forward and backward, rotating on pivot pins in the frame or drive axle.
- Hydraulic System: Oil flows from the main control valve to the lift cylinders for extension and returns through lowering control valves to the hydraulic tank during lowering.
Mast Types Covered:
- Two-Stage Mast with Limited Free-Lift (LFL):
- Comprises an outer weldment and an inner weldment.
- Connected to the lift truck via pivot mounts and tilt cylinders.
- Two single-stage lift cylinders are installed at the back of the outer weldment. The base is mounted to the outer weldment, and the rod fits into a guide at the top of the inner weldment.
- Two lift chains are fastened to the outer weldment, run over sheaves on the inner weldment, and connect to the carriage.
- Operation: Lift cylinders extend to raise the inner weldment, and lift chains transfer force to the carriage.
- Two-Stage Mast with Full Free-Lift (FFL):
- Features an outer weldment, an inner weldment, and three single-stage lift cylinders.
- Allows the carriage to travel to the top of the inner weldment without increasing overall mast height.
- Two main lift cylinders are at the back of the outer weldment, with their rods fitting into guides at the top of the inner weldment.
- A free-lift cylinder is installed within the inner weldment.
- Two chain sheaves are on the free-lift cylinder rod, with chains connecting to a mount behind the cylinder and then to the carriage.
- Operation: All three cylinders receive oil simultaneously. The free-lift cylinder raises first (lifting the least weight) to move the carriage to the top of the inner weldment. Once the free-lift cylinder reaches its stroke limit, the main lift cylinders extend to raise the inner weldment. During lowering, main lift cylinders retract first due to greater load.
- Three-Stage Mast with Full Free-Lift (FFL):
- Consists of an outer, an intermediate, and an inner weldment.
- Utilizes three single-stage lift cylinders to raise the carriage and extend the weldments.
- Two main lift cylinders are at the back of the outer weldment, with their rods fitting into guides at the top of the intermediate weldment.
- A free-lift cylinder is installed in the inner weldment.
- Two main lift chains fasten near the top of the outer weldment, go over sheaves on the intermediate weldment, and fasten to the bottom of the inner weldment.
- Free-lift chains connect to a mount behind the free-lift cylinder, go over sheaves, and connect to the carriage.
- Operation: Similar to the two-stage FFL, oil flows to all cylinders simultaneously. The free-lift cylinder raises the carriage first. After it reaches its stroke limit, the main lift cylinders extend, raising the intermediate weldment, which in turn extends the inner weldment via lift chains. During lowering, main lift cylinders retract first.
Usage Features:
- Fork Adjustment: Forks are hook-type and can be slid along the carriage bars to adjust width for different loads. A lock pin secures the fork in position.
- Sideshift Functionality: The optional sideshift carriage allows hydraulic lateral adjustment of the load, enhancing precision and maneuverability.
Maintenance Features and Safety Precautions:
The manual emphasizes strict safety procedures for maintenance and repair:
- Lifting Heavy Parts: Always use slings, chains, or cables with adequate capacity and ensure loads are balanced. Avoid manual lifting of heavy parts.
- Personal Protective Equipment: Wear safety glasses.
- Power Disconnection: Disconnect the battery connector (electric lift trucks) or battery ground cable (internal combustion lift trucks) before any maintenance.
- Stabilization: Use correct blocks to prevent the unit from rolling or falling. Refer to the Operating Manual or Periodic Maintenance section for "HOW TO PUT THE LIFT TRUCK ON BLOCKS."
- Tagging: Always fasten a "DO NOT OPERATE" tag to controls when repairs are underway or needed.
- Work Area: Keep the unit and working area clean and orderly.
- Tools: Use correct, clean, and well-maintained tools.
- Parts: Use only HYSTER APPROVED replacement parts that meet or exceed original equipment specifications.
- Disassembly: Ensure all fasteners (nuts, bolts, snap rings) are removed before forcing parts.
- Fuel Safety: Exercise necessary safety precautions when handling flammable fuels (Gasoline, LPG, CNG, Diesel) and working on fuel systems.
- Battery Safety: Batteries generate flammable gas during charging; keep fire and sparks away, and ensure good ventilation.
- Mast Safety:
- WARNING: Mast parts are heavy and can move, posing a risk of serious injury or death. Never place body parts into or under the mast/carriage unless fully lowered or a safety chain is installed.
- Ensure power is off, key is removed, and a "DO NOT OPERATE" tag is in the operator's compartment. Disconnect/lock out the battery.
- Be cautious of forks when the mast is raised.
- Do not climb on the mast or lift truck; use a ladder or personnel lift.
- Do not use blocks to support mast weldments or restrain their movement.
- Follow specific repair procedures in the service manual.
- Working Near Mast Procedures:
- Always lower the mast and carriage completely, pushing the lift/lower control lever forward to ensure no movement.
- If parts must be raised, install a minimum 3/8 inch safety chain to restrain moving parts (e.g., inner weldment to outer weldment, or carriage to outer weldment).
- Align crossmembers, raise the mast, install the safety chain, then lower the mast until tension is applied to the chain.
- Install a "DO NOT REMOVE" tag on the safety chain(s).
The manual provides detailed instructions for removal, disassembly, cleaning, inspection, and assembly of various mast components, including carriages, forks, and the different mast types. It also covers mast operation checks, lift and tilt system leak checks, tilt cylinder stroke and backward tilt angle adjustments, lift chain adjustments, mast adjustments, carriage adjustments, and troubleshooting.
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