Robust bearing technology for unscrewing and emptying bottles

Rink GmbH & Co. KG develops and produces systems that prepare returnable bottles for reuse. Up to 60,000 corks are removed or caps unscrewed per hour. Within just two and a half eight-hour shifts, a machine uncorks one million returnable bottles in a very compact installation space. All moving parts achieve very high cycle rates within a very short time and are subjected to high stresses.

Rotary machines for unscrewing bottles:
Currently, rotary machines that unscrew individual bottles are in particularly high demand. Although these machines require more space in the overall system, the user is more flexible. As this requirement increasingly applies to higher throughputs, Rink has now expanded its rotary unscrewing machine programme and developed a new machine type for unscrewing up to 30,000 individual bottles per hour. One of the requirements for the new rotary unscrewers was a linear bearing for the tool head, which moves the rotary unscrewer up and down in an undulating motion.

Unscrewing bottles in small containers:
In another project, the developers at Rink also optimised the bearing point. This is a new and very compact unscrewing head that plunges into crates with a small pitch for small containers. In the linear unit for the immersion movement

Valve for emptying bottles:
In a third application example, the designers focussed on a valve that is used in the systems for emptying bottles. The machine head with the valves moves into the box, the valves seal, build up pressure and press the liquid out. Due to the height adjustment, a vertical movement of the valves with corresponding sealing is required. Originally, Rink used classic piston guide rings for the hydraulic cylinders for this task, which often did not provide the desired stability.

It goes without saying for the Rink engineers that plain bearings from our bearing portfolio were used in the design of these system components. Our plain bearings offer very good sliding properties with a long service life and are also ideally suited for use in the beverage industry because they are maintenance-free and do not require lubricants.
Rink's design engineers use very different bearings in almost all machine types:

drylin® R linear bearings with linear plain film and stainless steel shaft:
Bearings made of the all-round material iglidur® J are used in the smaller rotary machines.
For the new larger models, the designers tested alternatives such as iglidur® J200 and iglidur® E7 and both aluminium and stainless steel shafts to optimise the running performance. Today, the linear bearing drylin® RJUM complete with linear plain film JUM-01 and a precision stainless steel shaft of type AWMP is used here (see Figure 1 below). The result is a very favourable coefficient of friction. The service life could also be tripled.

Bearings made of iglidur® Z
Bearings made of iglidur® Z are used today for the plunge movement of the unscrewing head, after the first unscrewing heads were still equipped with bearings made of iglidur® J and iglidur® W300 (Fig. 2). The head bearing is extremely wear-resistant and the users are very satisfied.

Guide ring made of iglidur® J
Finally, a guide ring made of iglidur® J is used for the bearing of the valve head when emptying bottles. The high-performance polymer is resistant to chemicals and is characterised by low moisture absorption (Fig. 3). In addition, the guide ring made of iglidur® J is easy to install and is backwards compatible. This means that the surrounding design does not have to be changed. These bearings have now been the standard at Rink for several years - especially as they are cost-effective and quickly available as catalogue parts.