Few days ago, I came across what is called "Pallet shuttle system" which is used in pallet rack system as an alternative to "drive-in" and "drive through" of fork lifts to save time and increase safety levels.
The following table shows some useful selection criteria. It is also useful for people who are willing to design this piece of equipment. Based on the table below, and by some reversed engineering of the top brands manufacturing this equipment; I found that "Mecalux" is really the best design from all aspects.
The following table shows some useful selection criteria. It is also useful for people who are willing to design this piece of equipment. Based on the table below, and by some reversed engineering of the top brands manufacturing this equipment; I found that "Mecalux" is really the best design from all aspects.
| Radio pallet shuttle system selection | |
| All pallets are of the same item | Yes |
| Mixed items: Pick one item from one end and the other from the other end |
|
| Handling equipment | Fork lift and stacker |
| Shuttle dimensions | _ |
| Minimum pallet size | _ |
| Maximum pallet size | _ |
| Maximum pallet overhang distance | _ |
| Maximum pallet deflection | _ |
| Maximum track distance | _ |
| Lifting distance | _ |
| Underneath ground clearance | _ |
| Operating conditions | |
| Operating temperature: Negative operating temperatures for refrigerators |
|
| Humidity | |
| Ingress protection IP | |
| Dynamics | |
| Four wheel drive | Preferred |
| Maximum load [kg] | _ |
| Full-load speed | _ |
| No-load speed | _ |
| Acceleration and deceleration profiles | _ |
| Lifting speed | _ |
| Weight-dependent acceleration | |
| Number of wheels to extend life of wheels | |
| Lift the whole upper plate | |
| Energy and efficiency | |
| Energy consumption to fully charge the battery | _ |
| Regenerative breaking system | Preferred |
| Standby mode | Yes |
| Monitoring and control | |
| Monitor battery charge remotely | Yes |
| Monitor battery remaining time remotely | Yes |
| Switching between manual and automatic modes | Yes |
| Remote control | Yes |
| Remote control communication technology requires no infrastructure | Yes |
| Handheld remote control | Yes |
| Rechargeable remote control | Yes |
| Remote control battery level indicator | |
| Light display in remote control | Yes |
| Remote control drop down distance | 3 meters |
| Magnetic mount remote control | Yes |
| Large buttons and icons in remote control | Yes |
| Iconic color-coded buttons | Yes |
| Single-hand operated remote control | Yes |
| Single remote controls multiple shuttles | Yes |
| No. of controlled shuttles using single remote | Unlimited |
| Remote control range [m] | _ |
| No interference between multiple remote controls | Yes |
| User accounts and authentication | Yes |
| Configuration | |
| PC programmable | Preferred |
| Programmable maximum speed | Preferred |
| Programmable maximum acceleration | Preferred |
| Programmable loading and unloading positions | Yes |
| First In Last Out Loading and unloading in the same location |
Yes |
| First In First Out Loading and unloading are in opposite locations |
Yes |
| Programmable home (for FIFO system) | Yes |
| Connectivity | |
| RS232 | Yes |
| RS485 | Yes |
| Ethernet | Preferred |
| Wi-Fi | Preferred |
| Features | |
| Shuttle power permanent push button | Yes |
| Power indicator light | Yes |
| Forward and backward blinking indication lights | Yes |
| Auto-homing | Yes |
| Auto-home and stop when battery is very low | Yes |
| Partial loading | Yes |
| Partial unloading (unload certain amount of pallets) | Yes |
| Automatic loading (LIFO) | Yes |
| Automatic unloading (LIFO) | Yes |
| Unload one-by-one, to reduce number of reallocations. This saves energy and increase the life time of the shuttle. In this mode, the default home position will be the unloading side and when the shuttle detects that the pallet is removed it will go back and bring the next pallet | Yes |
| Partial compacting | Yes |
| Full compacting | Yes |
| Self-align shuttle with pallet | Yes |
| Weight measurement | Preferred |
| Odometer | Preferred |
| On-deck pallet detection | Yes |
| Detect any pallet regardless the material: [1] Wood [2] Plastic [3] Steel |
Yes |
| Detect any pallet regardless the color | Yes |
| Detect any pallet regardless the pattern | Yes |
| Pallet size detection | Preferred |
| Variable pallet size | Yes |
| Programmable pallet spacing | Yes |
| Counting number of pallets | Yes |
| Calculate remaining pallets to fully-load the track | Preferred |
| Wide-angle navigation camera on both sides | Optional |
| Flash light for camera | Yes |
| Speed monitoring | Preferred |
| Audible alarm | Yes |
| Shuttle number (ID) label on: [1] Front [2] Back [3] Bottom (large) [4] Top (large) |
Yes |
| Bottom lights to easily recognize the shuttle specially when the shuttle is at elevated heights | Preferred |
| Possibility of two shuttles in the same lane (for FIFO) | Preferred |
| Forced operation function | Yes |
| Location signal To know where the shuttle cart is |
Yes |
| Alarm when there is a place left for only one pallet and the labor place a pallet above it | Yes |
| Auto-seek remote coverage | Yes |
| Battery | |
| Rechargeable battery | Yes |
| Battery technology | Lithium
polymer Lithium ion |
| Sealed battery | Yes |
| Fire retardant casing | Yes |
| Battery life (years) | 5 |
| Battery life (number of charges) | 1000 |
| Battery price (cheaper battery is preferred) | |
| Battery charger | Yes |
| Battery charger rating | 220 V - 50 Hz |
| Battery charger stop after charging is complete | Yes |
| Battery full-charge alarm | Preferred |
| Battery charging time | < 8 hours |
| Battery charge percent indicator in the charging station | Yes |
| Battery discharge time at maximum load | > 8 hours |
| Battery location is close as possible to the side edge of the shuttle, so it can be removed ergonomically | Yes |
| Battery weight (for ergonomics) | |
| Battery number label | Yes |
| Onsite charging | Preferred |
| Charging station for single battery | Yes |
| Spare battery | Yes |
| Standby operating time | _ |
| Remove battery without any hand tools | Yes |
| Safety | |
| Rail end stoppers | Yes |
| Pallet centralizers | Yes |
| Emergency push button on both sides (front and back) | Yes |
| Human hit safety (specially for ground racks) | Yes |
| Auto-home at enough distance from the rack end, so the fork lift will not hit it during unloading. | Yes |
| End of rail (track) detection (using two sensors) | Yes |
| End of rail (track) detection sensors can detect track end of any color | Yes |
| End of rail (track) detection sensors can detect track end full of dust | Yes |
| Open rail (track) detection | Yes |
| Anti collision with other pallet | Yes |
| Obstacle detection | Yes |
| Rail detection | Yes |
| Rail bump detection | Preferred |
| On-floor detection | Preferred |
| Bottom anti-slip surface to avoid slipping from fork lift | Yes |
| Electromagnetic locking
system: Bottom very strong electromagnets to hold firmly with fork lift |
Preferred |
| Electromagnetic locking system indictor light in the bottom | Preferred |
| Detect if it is lifted on fork lift, so it will not operate even if it is in automatic mode | Yes |
| Stop laser beams when it is lifted on fork lift | Yes |
| Rubber bumper at the front and end | Yes |
| Rubber stoppers at both sides in the front and back to avoid hitting track stoppers | Yes |
| Wheels are almost at the end of the shuttle to prevent flipping back | Yes |
| Pallet slip detection: Stop in case of pallet slip. |
Yes |
| Pallet flip detection: Stop in case of pallet flip. |
Yes |
| Side rollers to make sure that the shuttle is always on track | Yes |
| Anti-slip surface | Yes |
| Braking system | Yes |
| Sealing plugs (caps) for all communication interface ports on the shuttle | Yes |
| No wires, shrink wraps, clamps, frames can tangle with wheels | Yes |
| Ratchet lifting | Preferred |
| Human cart accessory (with chair inside) | Yes |
| Shuttle can not move if placed on normal floor | Yes |
| Reliability | |
| Electromechanical lifting system | Yes |
| Overload protection: [1] Over current [2] Over temperature |
Yes |
| Overload indication | Yes |
| Battery over-discharge protection | Yes |
| Spring loaded rail wiper to clean rails and avoid wheel slippage and wheel pitting | Yes |
| On-shuttle battery level indicator | Preferred |
| Wheel slip detection | Yes |
| Normally free to move when battery is dead | Yes |
| Normally not-elevated when battery is dead | Yes |
| Rust free materials | Yes |
| Dust proof sensors | Yes |
| Moisture proof sensors | Yes |
| Another shuttle can push or pull faulty shuttle | Yes |
| Shuttle can be lifted using fork lift if it is placed on flat floor | Yes |
| Shuttle have underneath pocket for forklift | Preferred |
| Front and back hooks for pulling it in case of getting faulty | Yes |
| Easy replaceable wheels | Yes |
| Protective guard for buttons and user interface when hit another object | Yes |
| Maximum load label on the top (readable from both sides) | Yes |
| Weight overload audible alarm | Yes |
