A stacker crane load handling device (LHD) is the interface between the mast, the drive, and the unit load; the choice between a telescopic fork and a shuttle-mounted fork directly sets storage depth, cycle time, and aisle geometry [S3][S5].
In a 2025 product update, MIAS lists single-deep, double-deep pickup, miniload, heavy-duty, and shuttle variants as separate fork families served by the same crane platform, and reports travel speeds up to 240 m/min with lifting up to 120 m/min on the PAL 23 series for 23–30 m buildings [S1]. Interlake Mecalux's 2021 single-mast table (still the public reference numbers in 2026) caps max travel at 722 ft/min (~220 m/min) and max lift at 217 ft/min (~66 m/min) across the MT-1 to MT-5 line, with pallet payloads between 1.1 t and 1.65 t [S2].
Definition: what each device actually is
A telescopic fork is a fixed-body LHD with two (single-deep) or three (double-deep) sliding arms driven by a motor through a transmission shaft, extending bilaterally into the rack to deposit or extract a pallet; triple-deep variants add a third stage for 3-pallet lanes [S2][S4].
A shuttle fork is a telescopic fork integrated onto a free-navigating carrier (rail-guided pallet shuttle, four-way shuttle, or mini-load shuttle) that handles the horizontal move inside the rack, leaving the stacker crane to do only the aisle traverse and lift [S3][S6]. The "fork" mechanism is mechanically the same telescopic slide; the difference is whether the X-Y motion is provided by the crane mast or by the carrier on the rack [S5].
Selection criteria: depth, height, load, throughput
Depth is the first cut: single-deep telescopic forks use a fixed body plus two mobile elements and suit standard FIFO racks; double-deep forks add a third element to reach the second pallet, while triple-deep forks extend bilaterally to a third lane for maximum cube in low-rise buildings [S4].
Height and load cap the crane side: the MIAS PAL 23 covers 23–30 m with a 20% weight reduction vs the prior series, and the Interlake MT-5 reaches 148 ft (~45 m) single-deep or 148 ft double-deep at 1.1 t max permitted load [S1][S2]. The MT-1 through MT-3 hold 1.65 t single-deep but only 1.1 t double-deep, illustrating the standard height/load trade-off on telescopic-fork stacker cranes [S2].
Throughput is the second cut: telescopic forks cycle in one crane move per pick, which is fastest for high-turnover SKUs in narrow aisles; shuttle forks decouple in-aisle travel from the crane so a single stacker can feed many lanes, winning on density and energy-per-pallet but losing on peak single-SKU retrieval speed [S3][S6].
Comparison matrix: telescopic fork vs shuttle fork
The four criteria that matter at the purchasing stage line up as follows, all anchored to published OEM numbers. [S1]
Storage depth: telescopic fork = 1, 2, or 3 pallets deep (single, double, triple-deep variants from Eurofork, MIAS, Interlake) [S2][S4]; shuttle fork = typically 2-deep on each side per carrier, scalable to 10+ deep by adding shuttles per level [S3][S6]. Telescopic wins for shallow, fast-turn lanes; shuttle wins for deep-lane cube.
Peak throughput: telescopic fork on a single-mast stacker hits up to 722 ft/min travel and 217 ft/min lift with 2 ft/s² acceleration [S2]; shuttle systems trade single-crane peak speed for parallel handling, since the shuttle can stage the next pick while the crane returns. Pick the side that matches your SKU profile: many SKUs at medium depth = telescopic; few SKUs at deep lanes = shuttle.
Load envelope: telescopic-fork stacker cranes are published at 1.1–1.65 t per pallet across the Interlake MT range, with the heavier ratings only available at lower heights [S2]; heavy-duty telescopic forks from MIAS and Eurofork extend to heavier unit loads by widening the fork spacing and adding a gear drive stage [S1][S4].
Environment and footprint: stacker cranes with telescopic forks operate in -22 °F to 104 °F ambient (Interlake MT series) and need a bottom rail plus an upper guide rail fixed to the rack profiles for stability during fork insertion [S2]; shuttle-fork carriers sit inside the rack on dedicated rails, so the stacker crane aisle can be narrower and the rack can be taller without the upper guide rail, but each lane needs its own shuttle hardware [S3][S6].
Who it is for, who it is not
Telescopic-fork stacker cranes are the right LHD for green-field pallet AS/RS up to ~45 m with FIFO or mixed-depth racks, for cold stores running 24/7 at -30 °C ambient, and for sites with a moderate SKU count where a single crane can keep up with peak hour picks [S2][S3]. Eurofork publishes variants for cold storage, automotive, coils, boxes, and pallet lines, confirming the cross-sector maturity of the telescopic fork [S4].
They are the wrong choice when single-SKU pick latency is the SLA, or when a tight FIFO audit trail is mandatory and the WMS cannot reliably re-sequence shuttles [S3].
Failure modes and constraints to spec in
Load-bearing capacity of a telescopic fork is the first spec to verify: deflection under full load at full extension, not just static capacity, is what sets the safe cycle count, and Dem Fork and other Chinese LHD makers publish deflection data as the headline number on their datasheets [S8].
Drive architecture matters: Eurofork's "variant version" uses separate transmissions for each slide so a single-deep and a double-deep SKU can be stored in the same rack without raising the moving-mass height, which reduces structural rack cost but adds a second motor and a second encoder to the LHD bill of materials [S4].
Miniload vs pallet fork is a hard fork: telescopic forks on a miniload crane (e.g. MIAS AKL) handle totes, bins, and cartons with grippers or extractors instead of pallet tines, so the "fork" name covers slides, belt conveyors, and gripper heads; specifying a pallet telescopic fork on a miniload crane is a common line-item error [S1][S5].
Standards and sourcing notes
Public LHD literature in 2025-2026 does not pin a single IEC or ISO standard to the telescopic fork itself; the relevant umbrella is the AS/RS machinery standard ISO 3691-4 for driverless industrial trucks, which applies to shuttle carriers and to stacker cranes when they operate without onboard operators [S3].
Component-level certifications that do appear on OEM datasheets are CE conformity on the LHD (mandatory in EU deliveries) and ATEX ratings for cold-store or pharmaceutical variants, with Eurofork stating the use of "components from the best worldwide brands" and "certified materials" without naming a specific steel or polymer grade [S4]. For procurement, the cleanest cross-check is the OEM factory-acceptance test report for deflection, cycle count, and ambient-temperature performance, not the marketing brochure [S1][S4][S8].
Recommended decision path
Start from the storage-depth target: 1 pallet deep and 24/7 FIFO = telescopic single-deep; 2 pallets deep and a crane height above 30 m = telescopic double-deep if the SKU count is moderate, or shuttle fork if the SKU count is high and the building cannot grow [S2][S4][S6].
Lock the load envelope at 1.1 t for any double-deep or triple-deep telescopic fork above 30 m height, and only specify 1.65 t if the rack stays under the MT-1/MT-2/MT-3 height limits; heavy-duty telescopic forks from MIAS or Eurofork are the path above 1.65 t but require a wider aisle envelope and a heavier mast [S1][S2][S4].
For shuttle-fork systems, confirm the WCS/WMS interface supports shuttle re-sequencing and per-lane inventory tracking, and budget one shuttle per 50–80 storage positions as a planning rule, since each shuttle is a separate maintainable asset [S3][S6].
Track two signals in the next procurement cycle: OEM release of deflection-versus-extension curves on telescopic fork datasheets (Dem Fork and Eurofork already publish partial curves) and the WMS vendors shipping native shuttle-fork lane-balancing modules, since both will tighten spec writing in 2026-2027 [S4][S8].
For component-level specifications, see shuttle system, material handling, and pallet stacker.
Background reading: CSI 07 13 00 vs 07 14 00: Sheet vs Fluid-Applied Waterproofing.