SPU 2040 Accumulating Pallet Recirculation System

Feeding and Buffering Workpieces in the Tightest Spaces

The SPU 2040 is an accumulating pallet recirculation system for cost-effective interlinking, feeding, buffering, positioning and separation of workpieces in the tightest of spaces with automatic workpiece carrier recirculation. The system’s sturdiness and wide range of variants makes it suitable for virtually all automation and material flow applications.


The SPU 2040 allows for acyclic operation (i.e. independent of the infeed cycle) with automatic recirculation of the workpiece carriers. The workpieces on the workpiece carriers are transported by the flat top chain along the upper transport level. The workpieces on the workpiece carriers are transported by the flat top chain along the upper transport level. They are then available at the start of the belt to be loaded with new workpieces. This eliminates the need for a second conveyor level or lift-and-lower units with complex control elements. It also eliminates the need to load the workpiece carriers on the belt, whether manually or automatically.

Single-line SPU 2040

Dual-line SPU 2040

Double-line SPU 2040

SPU 2040 Features

  • Cost-effective and very compact interlinking of two machining stations
  • Reliable and dynamic feeding, buffering, positioning and separating
  • Compact design with space-saving recirculation of workpiece carriers below the transport level
  • Buffering capability compensates for different cycle times within the production line
  • Built from proven mk modules and a variety of workpiece carriers for outstanding flexibility
  • Speed-dependent load capacity up to max. 300 kg (single line) and 450 kg (dual line and double line)
  • Transfer lines from 2 to 10 m in length
  • Speeds from 4 to 15 m/min
  • Low maintenance and wear

Overview of the Modules

SPU 2040 – Workpiece carrier


The single-line and dual-line systems can handle workpiece carriers lengths of 150 to 350 mm and workpiece carrier widths of 160 to 250 mm. The maximum weight for the largest workpiece carriers is 3 kg. In double-line systems, the workpiece carrier width depends on the conveyor width. The workpiece fixture must be known in advance to determine the centre of gravity.


Technical Data of Workpiece Carriers

  • Total load of 20 to 30 kg (workpiece carrier + fixture + product)
  • Support plates made from aluminium plates or Series 40 aluminium profiles
  • Positioning slot and positioning socket on the side
  • POM wear strip
  • Max. weight of the workpiece figure: 7.5 kg

SPU 2040 – Transfer Line​​​​​​​


The flat top chain conveyors are available in two different widths: SPU narrow with a flat top chain 114.3 mm in width, and SPU wide with a flat top chain 190.5 mm in width.The 114 system is built from 2 profiles with a cross section of 40 x 80 mm and can be used as a single-line or multiple-line solution. The larger 190 system is built from 4 profiles with a cross section of 40 x 40 mm and is used as a single-line solution when the workpiece weight is not centred and a larger support surface is therefore required. The flat top chain is made from wear-resistant carbon steel.


SPU 2040 – Drive​​​​​​​


Two drive types are available for the SPU 2040 system: a flange-mounted hollow shaft motor as a direct drive, and a gear motor with an output shaft as an indirect drive. Vulkolan pressure pads ensure secure transfer of pallets over the tail. The workpiece carriers are then automatically recirculated below the conveyor level to save space. Divided pressure pads allow for easy replacement.


Direct Drive Technical Data

  • Speed is adjusted via the motor
  • Location: left or right of the conveyor line
  • Drive sprocket wheel is connected to the motor via shaft/clutch combination
  • An optional slip clutch can be used in place of a dog clutch

Indirect Drive Technical Data

  • Speed adjusted via motor and sprocket wheel combination
  • Motor location: beneath the conveying path
  • Protective box on left or right
  • Optional slip clutch can be used

SPU 2040 – Tail

Vulkolan cleat pads ensure secure transfer of pallets over the tail. The system has an automatic or manual tensioning device integrated in the tail to set the required chain tension. Tensioning devices should be set according to the system’s length and the load. The automatic tensioning device operated pneumatically with a space-saving flat cylinder. The tensioning device is guided along linear roller bearing and guide rods. The tension distance is 30 mm. As alternatives, we offer the 114 system without a tensioning device and the 190 system with a manual tensioning device. The manual device is adjusted using an eccentric. The tension distance is 35 mm.

Centring Unit


The centring unit is connected to the side of the conveyor frame. The workpiece carrier is lifted and positioned using a pneumatic cylinder with a centring pin, with positioning accuracy of +-0.2 mm. Electrical or inductive stopper detection (SU 400) is possible. For the 114 system, the centring unit is available with an optional separation function.


SPU 2040 - Stopper/Separator​​​​​​​


Various stoppers are available for the SPU 2040 system: SElectric or inductive stopper detection is possible (SU 400), either damped or undamped according to your requirements. The permitted accumulated load is up to 400 kg, depending on the transport speed. The purpose of the separator units is to separate the accumulated workpiece carriers so that only one workpiece carrier is transferred to a positioning unit or tail. This ensures, for example, that multiple workpiece carriers are never transferred to the tail at the same time.

SPU 2040 - protective device guard


The protective device guard prevents anyone from reaching into the device during operation and reduces the risk of injury. The rotary lock is triggered when moved and stops the entire system. A cover between the flat top chain and the frame is available on request. The protective device guard is available in a profile-based design (shown here) or as a simple sheet metal guard.


SPU 2040 – Frame​​​​​​​


The base frame ensures that the system is stable and secure, and it can be ordered in various working heights. The frame is also available with optional panelling (sheet metal or Makrolon) and in a mobile version with casters. Alternatively, the system can be configured with individual stands.



For custom requests, please contact our technical sales department at info(at)mk-group.com, by phone at +49 2284598-­0 or using the contact form below.

* mandatory fields