Attachments: Efficient partnerships

By Sandy Guthrie10 July 2013

Doosan’s new quick coupler for wheeled loaders is designed to increase versatility of the tool carri

Doosan’s new quick coupler for wheeled loaders is designed to increase versatility of the tool carriers while ensuring optimum performance and safety

Attachments make construction machines more versatile, and the type and variety of work tools available for carriers is growing all the time.

From simple buckets to concrete mixers, breakers and screening units, there is huge variety in the market to cater for a wide range of applications, but the name of the game is creating the most efficient, safe and productive partnerships.

Take Steelwrist, for example – a Swedish manufacturer of quick couplers, control systems and tiltrotators (hydraulics tools at the end of an excavator arm that allow tools to be turned 360o and tilted up to 45o).

After just eight years in the business, it now manufactures products for excavators with an operating weight of between 2 and 30 tonnes, and has established some pretty heavy-weight partnerships. These include a recently extended relationship with Volvo Construction Equipment, which also bought a minority stake in the company.

Steelwrist already supplied Volvo CE with factory-fitted tiltrotators for excavators, and will now also supply the manufacturer with excavator quick couplers.

Steelwrist also signed a collaboration agreement with Yanmar Construction Equipment Europe to factory fit tiltrotators, and supplies a range of other OEMs with attachment technology, including Hanix Europe, which chose the company to supply its tiltrotators last year.

Stefan Stockhaus, CEO of Steelwrist, explained that the manufacturer’s new quick coupler technology was designed to maintain attachments in a safe position, even if the operator should fail in the connection procedure. The company developed front pin locker technology – claimed to be a unique feature in the dedicated quick coupler market.

“We manufacturer dedicated quick couplers, which can pick up only the bucket they are intended to pick up. This compares with universal quick couplers, which are more entry level products used with many buckets. However, it is easy and cheap to convert an original bucket to a dedicated style using a pre-manufactured bracket.”

Steelwrist is participating in standardisation work in an effort to increase safety and avoid incidents of dropped buckets. It is helping with the S-Standard (Symmetrical Quick Couplers for Excavators) industry open standard managed by Swedish organisation Maskinleverantörerna.

“A well designed symmetrical coupler makes it impossible to pick up any other work tool not designed for the coupler. This is a basic safety feature of the S-Standard which for instance the universal pin pick up couplers do not have,” Mr Stockhaus explained.

“In addition, thanks to our front pin locker technology, if the driver executes a command to lock the quick coupler, it will lock the work tool to the coupler. We are trying to safeguard against locking the coupler in a non-safe way.”

Dropped buckets

Safety is a big issue in the European attachments industry at the moment, said Mr Stockhaus. “Dropping buckets is a hot topic. There have recently been fatal accidents in Europe as a result of this,” he said, referring to two fatal accidents in Switzerland last year and a serious injury in Germany.

“We interviewed lots of drivers and found that the primary reason that buckets get dropped is because drivers believe they are fixed when they are not – and have forgotten to do a mandatory check.

“As well as front-pin locking, we are also working on a new red/green system for drivers – this means that even in the case of a false lock (when the bucket appears to be fixed as the coupler has locked, but the coupler has in fact locked outside of the bucket) the worst case scenario is that the bucket will hang from the top lock instead of dropping.”

Meanwhile, Volvo is also introducing a new range of excavator attachments that are designed to match the technical and performance characteristics of its machines. The range includes general-purpose and heavy-duty buckets for large excavators, a new line of hydraulic breakers for compact excavators, as well as attachments for Germanic markets.

The fact that, in addition to its partnership with Steelwrist, the manufacturer has also targeted specific designs to fit with Lehnhoff quick couplers in markets in Austria, Germany and Switzerland serves to further highlight the range of choice within Europe.

The main difference between Lehnhoff quick couplers and Steelwrist symmetrical quick couplers is that Lehnhoff models are based on a proprietary design, while Steelwrist models are based on an open standard design.

Volvo has designed a full range of buckets and other attachments to fit with old and current Volvo compact excavators in the Germanic markets, including low-noise breakers with German-type brackets.

Threefold safety

Another manufacturer of excavator attachments, Engcon, has also been developing new quick couplers. It has launched the Q-Safe for excavators, which features a threefold safety system – hydraulic monitoring, mechanical locking and electronic monitoring – targeted at reducing the risk of incorrect tool connection to a minimum.

Q-Safe is part of Engcon’s Non Accident Generation concept in which safety awareness is a key feature. With Q-Safe on an excavator, the bucket or other attachment must have a degree of ground contact to allow connection or removal. That is to say attachments cannot be removed while in the air.

For as long as the quick coupler is not fully locked, the excavator can only function at a significantly reduced speed. Full power is resumed only after the attachment has been correctly been connected and locked.

Locking takes place automatically by the attachment first being manoeuvred into a fixed, wedge-shaped position, with the simultaneous connection being made through a steel lip, which prevents the attachment from dropping or running the risk of swinging as both the forward and rear axles are locked.

In addition to the mechanical locking system and the safety lip, the attachment is monitored by two independent sensors that react on contact with both bucket axles.

“Profitability goes hand-in-hand with safe workplaces, where they are both dependent on each other,” said Stig Engström, Engcon’s founder and owner.

Meanwhile, Doosan offers four types of universal quick couplers in Europe, and Doosan heavy attachments team general manager Jurgen Gremez said these systems are also popular. Doosan has a new range of universal quick couplers for its new generation DL200-3 to DL420-3 Stage IIIB compliant wheeled loaders, together with a corresponding range of pallet forks and buckets.

Here, the focus has also been to increase versatility of the tool carriers while ensuring optimum performance and safety. Like other new quick couplers on the market, the Doosan wheeled loader product increases safety by enabling the operator to easily and quickly change attachments without leaving their cab.

Visual locking indicators further enhance safety, while an open frame design is said to lower the weight of the couplers and ensure maximum visibility for the operator.

“Every country has at least one system of preference/reference, and for each, you have countless manufacturers and brands to choose from. Europe is fragmented between universal pin grabbers and dedicated systems,” Mr Gremez explained.


Doosan is also developing a line of hydraulic breakers – the DXB Series – offering a fit for excavators from 1 to 38 tonnes, as well as two models for backhoes and one for skid steers.

“We offer a plug-and-play package,” Mr Gremez said. “By this I mean we offer a breaker, with two moil points, hoses, a tool box, and an inflating kit. This way, you’re ready to tackle the job right away, once you’ve fully charged the breaker with nitrogen.”

He added, “Needless to say that I am a strong believer that quick couplers will become more and more popular.”

Protecting uptime is another key issue in the attachments market at the moment. Contractors want powerful and robust work tools that are also highly reliable and capable of being put to work for long shifts.

Caterpillar engineering supervisor for work tools, Edward van Amelsfoort, said the company’s new line of grapples had been designed with increased uptime in mind.

Designed for Caterpillar hydraulic excavators and material handlers from 15 tonnes to 75 tonnes, the new CTV grapples – the CTV15, CTV20 and CTV40 – are designed to transfer large volumes of loose material such as grains, coal, sand and gravel, maximising productivity. Each model is available in range of capacities.

Mr van Amelsfoort said the shape of the shell was important.

“You need to provide a high fill factor,” he explained. “And the angle of the cutting edges ensures this. Also you can shift more material per hour thanks to the grapple’s fast opening and closing times, and they can be fitted with an optional scraper to help when dumping sticky material.

“We’ve also protected the hydraulic cylinder hoses by housing them internally, while new seals have been fitted to the shell’s pivot pins to protect from dust, for instance.”

Automated exchange

Caterpillar has also developed a new automated hydraulic quick coupler system – known as Auto-Connect, which Mr van Amelsfoort said fully automated tool exchange to allow work tools to be changed from the cab in just a few seconds.

The design of Auto-Connect is also said to prevent ruptured hoses and oil spills, avoiding unplanned downtime.

“Auto-Connect essentially standardises the machine interface at the work tool end,” Mr van Amelsfoort explained. “It supplies up to five hydraulic ports depending on application, two of which are high pressure, and can handle high flows at low back pressures – helping to boost performance efficiency.”

Safety is another obvious design point, and Mr van Amelsfoort pointed out the Auto-Connect’s built-in check valve, which is said to ensure the quick coupler maintains its work tool, even in the event of a hydraulics failure.

And flexibility is increased due to the fact that the Auto-Connect can also be used with purely mechanical tools.

“No conversion is needed,” said Mr van Amelsfoort. “The hydraulic coupling unit is always protected, even when operating a non-hydraulic work tool. The Auto-Connect has a two-step connection, first mechanical and then hydraulic. It can sense if it’s picking up a non-hydraulic tool like a bucket, and the hydraulic system stays idle.”

Doosan sister brand Bobcat has also been working on improvements to its attachment offering, including a redesigned concrete mixing bucket for its compact loaders. Approved for use on a range of Bobcat skid-steer and compact tracked loaders, the new concrete mixer attachment claims to allow users to mix, transport and pour concrete and cement more quickly than a stand-alone mixer.

A remote attachment control device also allows the operator to start/stop the loader and operate the concrete mixer from outside the loader. In common with most other Bobcat attachments, the 270 litre capacity concrete mixer is fixed to the loader via the Bob-Tach coupler system, which is said to ensure that the attachment can be fitted securely and safely to the machine in seconds.

Once the mix in the bucket of the concrete mixing attachment is ready, it can be discharged either by tipping the bucket forwards using the Bob-Tach attachment system, or through a hydraulically-controlled discharge gate at the bottom centre .

The company has also released a new expanded family of backhoe attachments for its compact loader range. For the first time, the range now offers a choice of three different types of backhoe distinguished by the system used to mount them on the loaders, comprising a Bob-Tach mounted backhoe, a centre-mounted backhoe and several side-shift backhoe models.

The Bob-Tach mounted backhoe attachment can be used on all the models in Bobcat’s new 500 platform of loaders, while the centre-mounted backhoe attachment is available for the company’s smallest S70 skid-steer loader. This is also mounted via the Bob-Tach system and is supplied with a mounting kit.

For larger Bobcat loaders, there are four different side-shift backhoes available – the 625S, 725S, R30S and R35S models. The side-shift system allows the loader to work close to walls. Front stabilisers are included as standard for enhanced stability and digging performance and rear stabilisers are optional.

Bobcat now manufactures 66 different attachments – and counting – for its loaders. It claims this range of choice and versatility is what makes them true multi-purpose machines, suitable for a range of applications.

A number of attachment options are also available for Gehl’s DL and more compact RS telescopic handlers, including swing carriages, log and pipe grapples and work platforms.

Gehl claims versatility is enhanced by hydraulic self-leveling lift action, which automatically keeps loads level as the boom is raised. The company’s Dynattach Quick-Attach system also allows quick attachment changes, with the operator leaving the seat only to disengage the attachment.

The latest introductions from parent company Manitou include a new concrete mixing bucket, high pressure water cleaner and an air-operated curb layer.

The concrete mixing bucket is said to be able to prepare any mixture in less than three minutes. It has a 500 litre mixing capacity.

The water cleaner, meanwhile, is driven by the carrier’s hydraulics and can wash machinery on construction sites without direct access to running water or electricity. It is fitted with a 600 litre tank which can run for 45 minutes at maximum pressure.

The new curb layer attachment can lay concrete curbs or components made of granite or other materials. Its support and handling system can also lift loads up to 160kg using an air vacuum.

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