High specification oil level indicators with scratch resistant glass

Elesa have introduced Brass bodied versions of their high specification oil level indicators with scratch resistant glass. These are likely to be of interest for external applications where electrical continuity and low spark energy are required, coupled with clarity of readings even under abrasive conditions.

The GN 743.3 in particular features good performance at high temperatures (up to 180°C) as does the GN 743.8 with conic thread, whereas the GN 743.5 features an AISI 303 stainless steel body for especially rugged conditions. Specially produced scratch resistant glass in the GN 743 series gives added confidence in the ability to establish clear oil levels even in conditions where cleaning normal glass would leave a blurring scratched surface.

For further information, e-mail: sales@elesa.co.uk  or view website: www.elesa.co.uk   Refer to page 54

Bottle recycling firm also recycles industrial robots

Recycling is now on most people's agenda, as a way of saving energy and conserving the environment, although recycling industrial robots is rather unusual. But leading UK robotics integrator, Barr & Paatz of Totnes, Devon, recently supplied two pre-owned SCARA type robots to an SME customer for performing conveyor loading and unloading duties. This high technology recycling initiative underlines the inherent flexibility and reusability of robots and confirms that these well-engineered machines will continue to give many years of reliable service.

The customer in question, Trading Green of Wadebridge, Cornwall, is usually associated with a more familiar form of recycling: it transforms used beer and wine bottles into an award-winning range of 'Green Glass' goblets, flutes and tumblers, which are widely sold in gift shops, museums and leisure attractions. Part of a largely craft process, which has been designed to be as energy efficient as possible, the two robots help perform routine and potentially hazardous grinding and annealing functions, freeing up operators to focus on quality control and removing, excuse the pun, a production bottleneck. So much so that productivity has increased by 45%, through automation of these two key tasks.

Glenn Slade, founder of Trading Green and the innovative Green Glass brand, first came across the idea of recycling old glass bottles into attractive glassware, when working on environmental projects in Africa. He wanted to earn a living 'doing something that felt good' and where his children would enjoy life, so he set up the Green Glass operation in a garden shed by the sea, in Cornwall.

Word spread and soon Green Glass products were listed in hundreds of gift shops, including such notable attractions as the Natural History Museum, Kew Gardens and the Eden Project. Output increased to 250,000 units a year, production outgrew the garden shed and, whilst still largely a manual operation, certain processes became repetitive, tedious and potentially hazardous.

Glenn approached robot specialist Barr & Paatz, with a tentative enquiry and a 'shoestring' budget, and was offered a pre-owned Bosch Rexroth turboscara SR8, a 4-axis machine with an 800mm reach, 5kg maximum payload capacity and repetitive precision of ±0.025mm. Now manufactured and marketed by Stäubli, the turboscara has all the performance characteristics suitable for loading/unloading duties, including very high speed, high rigidity, outstanding reliability, user-friendly programming under Windows, and an absolute encoder system, so the end-of-arm tooling 'knows' its position in the work envelope, without reference points.

Barr & Paatz designed and built a prototype CAD system,  to prove the principles and produce the initial software, then taught Glenn and his colleagues how to program and operate the machine, and provided back-up technical support. The first robot's function is to present the cut edges of bottles to a grinding machine, to ensure a perfect fit between the neck and the base, for bonding.

"They took to robotics very easily, especially having designed and built a lot of their existing machinery themselves. We prototyped the first system and provided template programs, then gave them technical training back at our site, but they actually installed the machine," says Barr & Paatz MD, Stirling Paatz. "After that, they've done everything themselves and installed, then programmed the second robot completely unaided. Actually, with the right training and guidance, other firms could do the same, because modern robotics is far more intuitive and user-friendly than many people think."

The second robot, another pre-owned turboscara SR8, took over a repetitive task that exposed workers, using insulated gloves and tongs, to intense levels of heat, to which they could be subject for only short periods of time. After the bottoms of the beer and wine bottles are cut off, leaving a raw edge, the robot places product continuously onto a flame polishing device, which produces a smooth, melted edge suitable for drinking. Once the bottles have cooled, the robot flips them over and places the product in rows on a conveyor belt leading to an annealing oven, for strengthening and destressing the glass; this application takes advantage of the turboscara's renowned belt tracking capabilities, which enable the robot to keep pace with the varying flow of bottles. The end-of-arm tooling was made in-house by Trading Green, combining a proprietary pneumatic gripper mechanism with what Glenn describes as 'Wallace and Gromit style' custom-made jaws.

"Given our green ethos, we try to keep the manufacturing process as simple and eco-friendly as possible, doing much of the work by hand, but there are certain functions that were potentially hazardous, especially as output increased. So we applied our recycling principles to robotics and integrated secondhand machines into the manufacturing process, while the guys who previously undertook those tasks now focus on operating the robots and quality control, to the benefit of our end-customers," says Glenn Slade.

"Since we never know exactly what type of bottle we shall be dealing with next," he continues, "robotics has another tremendous benefit, because setting-up times have been drastically reduced. Whereas with linear systems, we'd need to change things physically each time, the robots just have to be reprogrammed for different bottle sizes and heights and we're off."

"Robots are often viewed as something exclusive to large manufacturers and many smaller firms are resistant to the technology," he concludes. "But there are nearby small firms with processes like pouring molten wax or metal that could be performed more safely and accurately by robots. After all, such tasks aren't much fun and I know our guys are much happier, now they're not handling that type of job." For further information, email: s.paatz@barr-paatz.co.uk   

Custom torque sensors now available on standard lead times

A UK manufacturer of torque sensors is offering custom designed static/reaction torque transducers on similar lead times to its standard units, with only a small premium on the standard list price.

Applied Measurements Ltd, based in Aldermaston, is able to design and manufacture custom static torque sensors to meet any customer requirement, including different flange diameters, unusual sizes of square drive, special sealed versions and shorter, more compact designs.

According to Peter Lewis, Managing Director at Applied Measurements: "Many manufactured products require fatigue testing to ensure that they can operate for a guaranteed minimum period of time. An accelerated life test, for example, may be carried out on a drive shaft to determine the torque limits. The fatigue testing can sometimes be an afterthought. If this is the case, some kind of customised sensor is then required before the torque sensor can be coupled to the test unit. This is what Applied Measurements specialises in."

Whilst Lewis concedes that there are plenty of companies able and willing to supply static (reaction) torque sensors from their standard range, many do not offer customised designs, let alone on lead times that are similar to standard product.

Applied Measurements manufactures two types of static torque sensor as standard, a square drive mounting type and a flange mounted unit. The DTD-S square drive mounting sensor is designed specifically for measuring direct torque and is ideal for use in the calibration or testing of torque tools (screwdrivers, spanners, etc) in a quality assurance and inspection environments. The sensor is constructed from stainless steel and is protected to IP65. For fast, easy connection, the sensor is supplied with an integral, robust bayonet lock military connector. The DTD-S is available from 10Nm up to 50,000Nm as standard, with custom versions rated to 200,000Nm.

The DTD-F range of flange mounting static torque sensors are also designed to measure direct torque, but are ideally suited to fatigue test applications. Again, the units are finished in stainless steel and are protected to IP65. The sensor is provided with an integral, robust bayonet 'lemo' connector for fast, easy connection.

As Lewis continues: "The flange mounting sensors are normally used in applications where there are two mating faces, one driving or applying the torque and the other resisting the torque. For any torque sensor to work, there has to be a reaction or load to generate the resistance to motion and hence torque."

"While we offer customers a range of standard torque sensors, we also have the ability to design and manufacture custom versions, where the standard unit does not suit the application. It could be the size and shape of the sensor that needs changing, but could also include the need for odd size ranges that fall between the standard increments."

Lewis says this could include making the sensor longer, shorter, broader, or with different flange diameters and thicknesses. Units with different hole spacing or with an odd size of square drive may be requested. As an alternative to the square drive unit, Applied has also custom designed round shaft units with keyways. By creating a tubular design and applying the gauges internally, it is possible to create high integrity sealed units for wet environments. Other designs have included two-axis measurement of combined force and torque, pressure-compensated models or complete submersion units.

Applied Measurements has supplied custom static torque sensors to a variety of customers and industry sectors, including aerospace, marine, oil and gas, robotics, machine building and plastic moulding machines.

Applied Measurements in profile
Applied Measurements Limited offers a comprehensive selection of transducers based on strain gauge technology. The company's product range includes sensors to measure load, pressure, torque and displacement. In addition, a custom transducer design service and strain gauge bonding facilities are available.

To support the transducer range, a variety of analogue and digital instrumentation is available, including high resolution, high speed and RS232/485 equipped signal conditioners and indicators, as well as portable battery powered indicators with integral data logging, enabling the company to offer complete systems with calibration traceable to UKAS standards.

In addition to the standard transducer range, the company also has the capability to design, develop and manufacture custom devices to meet specific needs. Expertise is based on bonded strain gauge technology, which is carried across the company's complete line of transducers. Involvement in customer projects can be at any stage, from development and design, through prototyping, testing and into full production.

For further information on Applied Measurements' range of static torque sensors, email: info@appmeas.co.uk   Refer to page 70