It is generally assumed – and typical applications confirm – that metal bellows couplings reliably work over the entire service life of an installation, if the coupling is correctly designed. In the future, this can no longer be taken for granted as applications are becoming more and more dynamic. Such applications require you to consider additional criteria when selecting and designing a coupling. Read here about the most important factors which have to be taken into account.
A coupling is an element of a drive line that primarily serves the purpose of transmitting power from one shaft to another, thereby providing for the connection of the driving and driven machine. At the same time, shaft misalignments, e.g. caused by assembly inaccuracies, should be compensated by the coupling while generating minimum reaction forces.
The distinction is made between angular, radial and axial shaft misalignments which may also occur simultaneously. Depending on the coupling type you choose, the dynamic behavior of the entire drive line, and consequently of the machine and its production process, can often be influenced by adjusting the torsional stiffness of the coupling.
What started almost a century ago as buffer between railway cars has now become a universally applicable damping element for almost all industry sectors – also as a protective element against potential damages to buildings and industrial facilities caused by earthquakes.
The 9th International STESSA Conference on the Behaviour of Steel Structures in Seismic Areas took place from February 17 to 19 in Christchurch (New Zealand). This conference, which is triennially held, is organized by the Steel Construction New Zealand Incorporated (SCNZ) in cooperation with the University of Auckland, the University of Canterbury and the University of Naples. Like the previous STESSA Conferences, the University of Canterbury was selected to host this event.
This is part 3 of our series on surface treatments of components. Due to the great number of different chemical processes, we have split them up and explored these processes in the previous article:
- Chromate conversion coating
- Black oxide.
This blog article covers the remaining chemical processes commonly applied for the treatment of component surfaces.
In our first blog article we presented the most common mechanical processes for the treatment of component surfaces. In this second part, we address the most frequently used methods of chemical surface treatments. The decision as to which of the following treatments should be applied is predominantly influenced by design points of view, technical aspects and the intended appearance of the product.
The surface finish of components used in the field of mechanical engineering as well as of other products is not only determined from a design point of view, but is mainly defined by the technical aspects. From the onset, the specification of the requirements regarding the condition of component surfaces, e.g. of a shaft coupling, often has far-reaching consequences on the product development process, the resulting costs and, eventually, on the succes of the final product.
New year – new luck! This also means: a new attempt at keeping the good resolutions we keep on setting for ourselves at the beginning of a new year. We admit: we usually revert quickly to old habits. But, aren’t we annoyed with ourselves? So, why don’t you put into action one very important resolution commonly with us? We’ll show you how you can make your workday healthier with only a few tricks – this will not only help you work more effective and motivated, but in the long run, your health will also benefit from this.
The Christmas season – the time of rest and reflection? Well… instead of love, harmony, warmth and a sense of well-being, many of us actually associate the pre-Christmas period with stress, deadlines and overtime. A pile of projects heaped up on our desk which, ideally, should be completed before the holidays. In our private life, Christmas parties, visits to or from relatives and preparations for Christmas dinner make schedules even busier.
But, let’s be honest: the greatest cause of stress comes from our desperate search for suitable presents. After all, we would like to get something "special" for everyone.
If this sentence makes you nervous – don’t panic! We are going to show you how you can still please your loved ones with only four days before Christmas, in spite of your long to-do list.
The term ATEX is derived from the French denomination "Atmosphères Explosibles" (explosive atmospheres): The ATEX Standard comprises the Equipment Directive 2014/34/EU as well as the Workplace Directive 1999/92/EC. In a previous article about the ATEX Directive we put more emphasis on general issues and theory. In this article we use the example of a flexible claw coupling to explain in more detail how this standard is implemented in practice.
When it comes to automated warehouses, precision is key. Hundreds of shuttles and miles of conveyors must all work together to ensure products are transported successfully to their designated location for storage or delivery. Of all the components that play a role in the precision of these systems, do not forget about Couplings and Locking Devices – both of which are widely used in this application.
Today, Locking Assemblies and Shrink Disks are standardized elements which provide a frictional connection between a shaft and a hub. They are not only capable of reliably transmitting torque, but of axial and transverse forces as well as bending moments, too. Oskar Peter is the father of the Locking Assembly. He recognized back in the 50`s that a locking assembly, in contrast to a key, is able to transmit considerably higher torques, thus allowing the engineering of much thinner and shorter shafts.
The 17th edition of the biannually held EXPOSIBRAM took place from September 18th to 21st in Belo Horizonte (MG), Brazil. With a floorspace of 12.000 m², this exhibition is considered one of the greatest mining events in South America, gathering representives of government authorities, contractors as well as private organizations in the same place. EXPOSIBRAM also hosts the Brazilian Mining Congress, which is organized by IBRAM (Brazilian Mining Association).
This year, the 15th D-A-CH Conference, which is organized by the Societies of Earthquake Engineering and Structural Dynamics in Germany (DGEB), Austria (OGE) and Switzerland (SGEB) took place on September 21 and 22. September.
This gathering of experts is conducted biennially and serves both as the exchange of knowledge between seismologists and engineers and the presentation of current scientific findings and experience gained from field applications. In addition, companies operating in the fields of earthquake engineering and structural dynamics as well as manufactures of earthquake protection systems had the opportunity to present their application solutions in the foyer of the Bauhaus university.
In this blog article we are going to take a closer look at the API Standard 671 which specifies the requirements for special purpose couplings used in the petroleum, petrochemical and natural gas industries. This Standard has been developed by the American Petroleum Institute (API), which is not to be confused with the identical abbreviation used in the IT field (Application Programming Interface). Let's begin with a few details about the institute that gave the name to the API Standard.
When it comes to gearbox coupling applications, some misalignment is unavoidable. This is especially true for cranes and hoists due to their very heavy loads. Fortunately, you can manage misalignment by choosing the right couplings. Here are some of your options specifically for cranes and hoists.
A virtually rotational-symmetrical component may have an unbalance caused by production tolerances or non-homogeneous structure in the material. Such unbalances in a drive system can not only lead to considerable vibrations during operation, but, in the long run, can also lead to failures of individual components or even of the entire drive system. As speed constitutes one of the decisive influences here, balancing is always performed for a certain speed. As a general rule, this is the nominal speed of the drive system.
Company-owned balancing machine in Neunkirchen, Germany
Measuring processes unconsciously cross our daily paths more often than we are aware. Whether it is about scooping coffee for the coffee maker, the temperature of the coffee or the speedometer in a car - we encounter measurement technology everywhere. But, what is “measuring”?
A well suited definition is given here: “Measurement enables us to make statements about a measured parameter in relation to a unit of measurement”. Measurement technology allows the determination of parameters such as length, mass, temperature etc.
If buildings are shaken by earthquakes this can lead to cracks, instabilities in the support structure and in worst case szenarios to the collapse of the building. To efficiently absorb the enormous forces and thereby protect both, person and material, nowadays sophisticated technologies are available.
Not all damages that a great earthquake will cause can be avoided. However, with Friction Springs there is a very high probability, that the building withstands an earthquake – like those in Christchurch/NZ in 2010 and 2011 – and is still operational and habitable.
Since 1993 the annual exhibition and conference for the European energy industry presents new developments on the topics such as renewable energies, power plant technology as well as distributed energy generation. Since then the Power-Gen is deemed to be the leading trade fair for the power technology and energy industry in Europe, which takes place at changing locations every year. For the 25th issue of this trade visitor fair with its accompanying internationally oriented congress, organisers PennWell (UK) selected Cologne (Germany).
Who has not experienced the following? Arriving at the office in the morning and writing a to-do list, realizing at the end of the day that almost nothing has been finalized. There is always an additional, more important task or a colleague who needs a helping hand – faster, higher, further every day. The piles on the desks are not getting less. With a few tips and with discipline this can be changed. We have collected a few smart productivity hacks:
In a previous article we covered friction springs and their applications. This time we would like to explain the technical properties of a friction spring, how it works and why its features provide a variety of advantages compared to other damping systems.
Gas turbines are available in many different designs and the power output of the individual models varies considerably – from 200 kW to more than 400 MW. The performance of gas turbines for industrial applications typically ranges from 5 to 40 MW. Dependent on the power, the speeds vary from 3,000 rpm to 15,000 rpm. Please see below which couplings are typically used and which are the selection criteria.
The presentation for the customer, performing at an exhibition or an internal meeting: again and again engineers have to face the challenge to present their developments. This isn’t everybody’s job. A frequent obstacle: preparing a PowerPoint presentation eats up time – and in the end it does not look that professional in many cases. The following basic tips should change that!
Designers of plants and machines strive for the optimal selection of a coupling for the complete system with many variables requiring consideration. In most cases the main focus is not how maintenance-friendly the product is. Yet – one might say. For a sustainable improvement of the longevity and efficiency of plants, a stronger involvement of maintenance is a must.
One of the highlights within the scope of the core topic "industry 4.0" was collaborative robots, as the new aid workers are called within the sector. This was not only a core topic but also an eye-catcher. While conventional robots are so far separated from the human work processes by safety fences, these collaborative robots shall work directly with humans and thus support workers in their activities.
There are two “new” generations on the labor market: Who are the people behind Generation Y and Z, what do they stand for and are they changing the working world? Some companies will have to change their behavior and structure, because these generations do have different demands towards their working places compared to those before.
The Hannover Messe starts on April 24, 2017, and we are again excited to see what awaits us. There is one specific topic that stands in the foreground: The lead theme of the Hannover Fair this year is “Integrated Industry – Creating Value”.
Without question, engineers have to deal with many important tasks in their daily life. Their responsibilities are always being extended with everything a top priority which increases time pressure: more and more projects need to be handled with increasing demands in less time but stable quality. In addition, smartphones, tablets and notebooks are pinging and blinking continuously. How is it possible to use working time efficiently despite these facts?
Friction springs are indispensible safety components in all fields of technology where suddenly occurring forces have to be taken up and kinetic energy absorbed, or where springs are required with relatively compact dimensions while also being able to sustain high forces. Expert friction springs are needed when it comes to the deceleration of moving masses in a quick, safe and precise manner.
Engineers need to consider several aspects for selecting the appropriate coupling such as the type of installation, primary and secondary connection, available space of installation, ease of mounting and dismounting as well as maximum rotational speed and resilience of the coupling. To compensate physical parameters or changes that are not obvious the safety factor, also known as safety multiple or safety coefficient, is taken into account.
Steel is an essential part of our everyday life and especially in mechanical engineering an indispensable material. We would not be where we are today without it. Through research the areas of applications are broadening, new types of steel are developed and cover even more areas. It is astonishing how many varieties are available.
In an increasingly complex working world simple processes can be performed by machines, numerous data sources and cross-functional targets such as sustainability and efficiency need to be considered. This leads to increasing demands on employees – a challenge also engineers are facing.
We have previously reported about various elastomeric materials and their properties as well as the applications they can be used for in the field of mechanical engineering. This article is in reference to the raw material natural rubber or caoutchouc. For example, did you know that its natural color is white? Or how many tons are produced and processed every year? Everybody knows caoutchouc, but very few are familiar with its properties and for which applications it can be used. Here are 10 facts about natural rubber you may have not heard about before.
Operators of cement plants worldwide face the challenge to create their systems more efficient and reliable. Even though the production and consumption of this material is quite stable in Europe, there is a continuously growing demand in Africa, North America and Asia. For this reason, production needs to be optimized and therefore all components which are part of the drive to guarantee constant operation, minimal downtimes and low maintenance costs.
Details are important for engineers. The smallest discrepancies may have major consequences in their job. Therefore being precise is essential. This applies for the design activity as well as for communication among colleagues: Describing faulty processes and listening carefully to descriptions are everyday tasks of engineers. For these tasks the dialogue is the most obvious tool – yet its importance is underrated.
Elastomers are polymeric materials which have the property of high elasticity. By virtue of this elasticity in combination with their damping capability, elastomers are the preferred material for use as transmission elements in elastic or highly elastic couplings. 
Topics as varied as Big Data, Industry 4.0, Digital Transformation, Crowdworking, Generation Y , Work 4.0 and 3D-printing have been discussed in 2016, and many of these will have significant influence on the working world over the next few years. This also applies to mechanical engineering. We would like to refer to three terms that have gained importance in 2016.
Especially in narrow spaces, couplings can only be inspected visually, because the coupling is hardly accessible with conventional measuring devices. Atypical operation noise or vibrations are generally the first signals that there is something wrong with the coupling.
Catching you up on market news – Augmented & virtual reality and 3D printing: how to make the inconceivable tangible
3D printing meanwhile offers outrageous possibilities also for mechanical engineering; some highlights have been presented at the formnext 2016. This technology used to be considered as expensive, limited and quite slow, but the rapid development in this field led to innovative and flexible systems for production. Other news we have been really enthusiastic about are further developed augmented or virtual reality systems which can improve processes in manufacturing industries.
One of the distinguishing properties of elastomers is their high elasticity. The main characteristics of elastomers present themselves, in particular when comparing them to steel. Below we would like to elaborate on the main properties of elastomers in more detail. Figure 1 shows the main characteristics of elastomers. They are able to combine spring properties as well as damping ability in one component.
When thinking of resonance and race tracks the most obvious link appears to be the roaring of engines. But, it actually covers a much broader scope, which has been exhibited by Renault’s clever engineers at Formula 1.
Engineers are mathematicians with technical expertise. They act factual, follow findings based on calculations and rely on proven concepts. This is the stereotype. But many engineers are already acting exactly as requested by analyses of future trends in working environments: data-based, creative, planning and solution-oriented. Soft skills will no longer be a nice option – but a necessity.
Maintenance and repair: Characteristics of gear couplings, steel disc couplings and (highly) flexible couplings
Couplings are not the most critical part of plants but they have to meet continuously changing requirements. Being reliable, efficient and robust is no longer enough – they should be easy to maintain in order to reduce costs and to avoid downtime. So for choosing the right coupling its characteristics in regard to maintenance and repair are playing a more important role.
One of the most discussed topics in mechanical engineering but still it is hardly tangible for many companies and engineers. This is most likely due to the fact that the idea behind the so called forth industrial revolution is well-known, but there exist many different opinions and approaches when it comes to the implementation. We want to have a closer look at the current situation in the market.
Couplings in drive lines are of particular importance because they transmit power between the input and output side, and compensate for inevitably occurring misalignments of the units. Like other machinery elements, couplings need to be serviced at regular intervals. Only if the coupling is optimally tailored to the requirements of the operating conditions and subject to regular maintenance, can it contribute to ensuring the operating reliability and efficiency of a machine or plant.
It’s Oxymoron Day again! And while sitting together to choose the most creative proposals for oxymorons among your submissions, we randomly bumped into interesting facts about group dynamics. Some of them were surprising, some just funny. Therefore in addition to the most favored word pairs: ten facts about teamwork – not only for engineers.
The demands made on the components in combined heat and power plants (CHP) are increasing. They have to be efficient, long-lasting and, in case of an emergency, must at least fulfill the safety requirements set forth by the Medium Voltage Guideline. Thomas Marterer, Product Manager at RINGFEDER POWER TRANSMISSION, explains how operators of CHPs can find the correct coupling for their plant: The coupling should withstand high temperatures and be neither torsionally too stiff nor too soft.
Maintenance is a key factor determining manufacturers’ success since it ensures preferably smooth operation. At the same time service and repair are significant cost factors. We wanted to get a more detailed picture and started researching. Some of the most relevant findings:
"The challenge to develop a highly flexible coupling is to design a coupling which has a particularly soft characteristic curve", explains Norbert Telaar, Head of Strategic Product Management at RINGFEDER POWER TRANSMISSION, the main task of his team. In the end they developed an innovation in coupling design.
Pursuant to the supplement to the Medium Voltage Guideline in 2013, the certification directives for co-generation plants have been adopted and the obligation to furnish evidence of compliance with the BDEW guidelines of 2009 is now also binding for co-generation plants. As a result, certificates have to be furnished for CHPs connected to the medium voltage grid with reference to their behavior in the event of a failure.
Combined Heat and Power Units Assist in Securing Grid Stability, which particularly Challenges their Gensets
The amendment to the obligatory certification within the medium voltage guideline in 2013 catapulted combined heat and power units into a new league: they are now also in charge of stabilizing the dynamic German power supply network. This provides excellent opportunities for the technology, but it also means new obligations.
An oxymoron connects two contradictory terms. In the field of engineering this often means that the seemingly impossible has become possible. The same holds true for “flexible stiffness”. Learn what it is all about and let us know your personal favorite oxymoron.
Nowadays engineers are facing various challenges which can be solved by selecting the right coupling. Shocks, heat, cold conditions, efficiency and work safety: machines and their drives have to meet highest requirements.
The coupling is normally the softest element in the drive line, literally – but by no means the weakest link of the chain. Its configuration plays a decisive role for the functional capability of the driving and driven machine and for the reliability and lifetime of the entire drive system. The optimum adjustment of the coupling to the connected machine units is especially important in all cases where failures and breakdowns are not allowed to occur.
Bending stress, torque shock, natural frequency and resonance: all the machinery elements in drive systems – i.e. above all axes, shafts, bearings and couplings – must withstand such strains. The coupling plays a prominent system-influencing role which it continues to fulfill better and better due to advanced development.
Reciprocating Engines in Combined Heat and Power Units: Is Higher Power without Loss of Energy Efficiency Possible?
The combined heat and power technology (CHP), in particular co-generation units, have long been a part of the industrial energy transition. However, the large potential of combined heat and power units is still underutilized. The reason for this, among others, is because of the properties of the installed drive technology: for instance, the non-uniform torque of reciprocating engines. New components promise more power with consistently good energy efficiency.
The cut-off date has passed. The new EU ATEX Directive is now valid. Manufacturers, distributors and operators should keep themselves informed, since the old certificates are no longer valid for any products that will be newly launched onto the market. There are also amendments pertaining to operators, who themselves set up a plant or an assembly from several components, for example, with a pump, coupling and engine. The user will then be considered as manufacturer and must know the exact properties of the components used, including the coupling.
Stiffness describes the ability of a body to resist elastic deformation. The transmission of power would not be possible without stiffness. However, there are events which should not be transmitted, such as torque peaks and shock loads. In order for a system to withstand such loads, it is damped. Engineers are confronted with the challenge to tune stiffness and damping in a vibratory system in such a way that reliable operation, essentially free of load peaks, is ensured.
Every vibratory system consists of an exciter and a mass with a force-transmitting medium in-between. Resonance is caused if this system is periodically excited with its natural frequency. In the field of mechanical engineering, resonance is an undesired phenomenon.
The robust drill on the robot arm of the Mars Rover Curiosity helps scoop rock dust on Mars – a milestone for researchers. A friction spring made of stainless steel dampens the forces generated during the drilling process and prevents any resonance phenomena.
Residential Elevators designs, manufactures and installs elevators for home use. So the company is always on the lookout for design enhancements that will keep its elevators moving with the least amount of maintenance.
Many power transmission applications, including gearboxes, require a reliable connection between a solid and hollow shaft. This type of connection, however, only works well if the solid shaft outside diameter and hollow shaft inside diameter have been properly machined to exact dimensional tolerances and finishes. These precision machining factors drive up costs and limit the design freedom of solid-to-hollow shaft connections.
Bending moments are an unfortunate fact of life in many power transmission applications. But pulley-and-drum systems have an especially high risk of failure when exposed to these moment loads.
Choosing the right coupling style for a servo application can be confusing, but it doesn’t have to be. A better understanding of application requirements such as torque, stiffness, rpm values and shaft misalignment details can help narrow your selection.
Northern Power Systems, a large United States manufacturer of wind turbines, needed a reliable, economical locking device for their systems. In the past, they tried different splined or keyed shafts, but found that these connection methods were too expensive and created a weak point in the shaft connection.
Locking assemblies and locking elements come in so many sizes and with so many different technical features that it can be overwhelming to find the right one for your application. That’s why we recently developed our online calculation tool that makes it easy to select the right product.
The Ringfeder Rapid Response Program has been up and running for the past several months. Customers have taken full advantage of this program, which makes our most popular metal bellows couplings and shrink disc locking devices available overnight.
As you probably know, compact friction springs improve damping performance and give off high kinetic energy in a wide range of mechanical systems. Wabtec Corporation experienced this first-hand when they used our friction springs in their mechanical couplers for trains.
Our new Rapid Response Program gives new meaning to the term quick coupling.
If you build or maintain shaft-driven equipment, you may not have the luxury of waiting weeks for your couplings to arrive. Now you don’t have to wait.
Motor shaft couplings have to strike a delicate balance when it comes to stiffness. On the one hand, they have to be rigid enough to transmit torque efficiently. On the other, they have to be flexible enough to handle any misalignment between the motor and the drive shaft. Our latest coupling design can help you strike that balance.
The big gearboxes that drive cable drums do not come cheap. Yet engineers often
make a design mistake that can shorten the gearbox’s working life. This mistake
involves the use of a rigid, direct coupling between the gearbox output shaft and the cable drum.
Heavy-duty shaft couplings have traditionally had a couple of defining design characteristics. For one, these couplings usually rely on keyed shaft connections. For another, they tend to be overengineered with regard to stiffness.
Keyways aren’t the only way to couple heavy-duty motor and gearbox shafts. In fact, keyways aren’t even the best way when you consider the alignment and installation difficulties you’ll encounter when installing keyed shaft couplings that may weigh thousands of pounds. A better alternative is to use couplings that employ a mechanical shrink fit around the shafts.
RINGFEDER POWER TRANSMISSION Group has expanded its offering of heavy-duty couplings with the acquisition of TSCHAN GmbH, a leading supplier of non-shiftable mechanical shaft couplings.
Ringfeder Power Transmission's new RfN 5571 series of flange couplings for heavy duty applications offer easy installation and have higher torque capacity than standard press fits.