Reciprocating Automatic Hoist is a vertical conveying device driven by a motor or hydraulic system that moves a load platform up and down in a reciprocating motion, mainly used for automatic material transfer between different floors.

So, what are the key performance inspection indicators for a reciprocating automatic hoist?
I. Load and Mechanical Structure Performance
1. **Rated Load**: reserve a safety margin when selecting the model; chain breaking safety factor ≥ 5 times
2. **Off-Center Load Test**: place the goods on one side of the platform; the load platform should not jam or tilt, and the chain should be evenly stressed (many machines run normally when empty but shake under off-center load)
3. **Frame Verticality**: after installation, the verticality deviation of the whole machine ≤ 1/1000;
4. **Full-Load Deflection**: the deformation of the frame and the load platform frame at full load is generally ≤ 1/500 of the span, with no permanent deformation
5. **Chain**: even chain tension; reasonable sag control; no tooth jumping or abnormal noise; no obvious shaking during operation
II. Motion and Positioning Performance (Core for Automated Docking)
1. **Lifting Speed**: adjustable from 0.1–0.6 m/s; variable-frequency speed control with soft start/stop buffering, preventing goods from impacting and sliding
2. **Repeat Positioning Accuracy**: ±2–5 mm; when docking with conveyor rollers, inaccurate stopping will cause pallets to jam on entry and exit
3. **Cycle Rate**: cycles per hour; the actual effective cycle rate measured at full load (not the theoretical no-load speed)
4. **Acceleration/Deceleration Smoothness**: small start-stop impact, so bins/workpieces will not slip
III. Safety System (Veto Items)
1. **Brake**: power-off braking, locking the load platform immediately when power is lost; emergency braking is reliable, with no platform slipping
2. **Limit Switches**: working limit + ultimate hard limit (two-stage protection) to prevent over-travel at the top and bottom
3. **Chain-Break Protection + Anti-Fall Device**: locks the load platform instantly when the chain breaks — a core safety protection that must be simulated and tested on site
4. **Overload Protection**: when the load reaches 110% of the rated load, alarm and prohibit startup; at 120%, cut off power
5. **Safety Door Interlock**: when the guard door is open, the machine cannot start; opening the door during operation stops it immediately
6. **Buffer Device**: bottom buffer block to prevent impact from a falling load platform
7. **Emergency Stop Circuit**: effective over the full travel, with fast stop response; resetting the emergency stop requires manual confirmation before restart
IV. Electrical and Control Performance
1. Insulation resistance: main circuit ≥ 0.5 MΩ, control circuit ≥ 0.25 MΩ, tested with a 500V megohmmeter
2. Motor temperature rise: under continuous full-load operation, the motor temperature rise stays within the allowable range; bearing temperature ≤ 70℃
3. Stable encoder positioning; PLC fault alarm and self-diagnostics; supports signal handshaking with upstream and downstream conveyor lines and MES communication
4. Reliable grounding; grounding resistance of the whole machine ≤ 4Ω
V. Durability and Environmental Reliability
1. Continuous operation test: 8 h of continuous full-load cycling, then re-test positioning accuracy, chain and brake; no abnormal wear and accuracy degradation within limits
2. Workshop dust and humid environments: IP54 protection class optional; lubrication design for guide rails and chains
3. Anti-corrosion: frame sandblasted + painted, with paint film thickness meeting standards