Streets ahead

True, the branding was often not the same, but a Konecranes hoist is still a Konecranes hoist, even if it has notional alternative branding. It is also annoying for the original crane supplier when the hoist supplier then adds insult to injury by also competing for the post-sale service and parts business.

Over the years this message has been taken to heart, to the extent that last year, Street’s best ever, export accounted for over 70% of sales. By diligent canvassing in key markets, the company has recruited over 40 partners worldwide who are happy to build Street hoists into their own products.

The deal is simple. Within each territory Street Crane partners have rights to the distribution of Street hoists, subject only to the proviso that they promote the products actively and are able to move reasonable volumes. In return, Street Crane gives regional exclusivity and commits not to enter their market in competition for whole crane business or after sales support. Over and above this, partners are involved in new product development to meet their specific market needs.

The ZX strategy

In the early years, overseas hoist sales were based on UK hoist designs. By adapting them on a case-by-case basis they were made to meet different local market needs. This was an adequate response because engineering standards in the UK are high. However, bespoke adaptation is costly and often results in a product that is over-engineered for a required job.

The ZX programme’s simple aim is to expand the standard hoist range to meet customer requirements more closely, improve performance, increase reliability, reduce lifetime cost and make the package more competitive.

This, Street says, is being achieved by:

- adopting modular designs to maximise the number of multi-role elements in the design and reduce the overall number of components;

- using technology to optimise the design process;

- simplifying the assembly process to reduce build time;

- adopting a ‘best engineering solutions’ approach to maximise service life, reduce lifetime cost and servicing requirements;

- designing for international compliance.

The first hoists to emerge from the programme were the ZX6-8 series 0-25t hoists, which were launched last year. It was always the plan for the ZX10 to take the range through to 50t SWL. Phase one of the ZX10 programme sees hoists up to 40t available from October 2009, with the range extending to 50t in the phase two launch in January 2010.

In every aspect the ZX10 series is a heavy duty hoist having a more substantial chassis, heavy duty gearbox, motor and drum. There is some capacity overlap at the bottom end with the ZX6-8 in the core 20-25t lifting ranges. The ZX10 hoists in these ranges give Street Crane the possibility to offer significantly faster hoisting speed, greater height of lift and higher duty rating in standard hoist formats.

“The ZX series are genuinely world-class hoists, with standard solutions engineered to meet a host of national and international standards,” says managing director Andrew Pimblett. He refers to:

- European norms, specifically EN14493 part 2;

- for the USA it complies with the HMI (Hoist Manufacturers Institute) and CMAA (Crane Manufacturers Association of America);

- ISO (International Standards Organisation);

- for Canada the hoists comply with the standards of the CSA (Canadian Standards Association);

- additionally, the hoists comply to national standards in Australia, China and India, “with many others pending”.

Electrical requirements vary and Street Crane has a range of standard motors to meet local requirements in the USA, Canada, Europe, China, India, Saudi Arabia, Australia, South America and other territories. The ZX series hoists are suitable for operation in ambient temperatures of up to 50°C, “something many competitors cannot achieve,” says Pimblett. Also, a long list of optional equipment is available including digital load readouts, over speed switches, and VFD hoist and trolley drives using the latest sensorless current vector techniques.

Safety is a prime consideration. “For this reason Street Crane hoist brakes act on the gearbox shaft and not on an extended motor shaft which is the case on most competitor hoists.” A brake acting on the gearbox shaft will hold the load in the event of a motor shaft, motor coupling or motor connection failure. With this configuration the gearbox brake will even hold the load if the motor is removed, he explains.

“This set up has been extremely popular in the USA where the market has traditionally seen many American manufacturers using Weston-style load brakes as an additional safety feature. Load brakes are not offered by many manufacturers today, but the perception that it is better to have something superior to a simple brake/motor works to Street Crane’s advantage.”

Engineering solutions

The development programme for the ZX series hoist examined the role and function of every component. As Ian Wing, Street Crane’s technical director explains: “Design is often a matter of compromise, especially when cost considerations are dominant, but one of the key principles underpinning the ZX programme was to ensure that safety and performance remained factors that would differentiate our crane products from the rest.”

Take the absence of open gears in the hoist or travel mechanisms, for example. “Many manufacturers opt for the low-cost option of cutting a spur gear into the hoist drum. This is a ‘free reduction’ but there are questions as to how effectively the open gear can be lubricated and therefore over its long-term reliability and serviceability,” Wing adds.

Street Crane says its gearbox differs from that offered by most manufacturers in that the additional reduction gear is located within the gearbox and so is totally enclosed with no exposed gears. All gears are case hardened and immersed in an oil bath for effective lubrication and extended trouble-free life.

There are four elements to the Street Crane quality system: virtual design modelling, the design management system (DMS), physical endurance testing and final tests before shipping.

3D modelling, allied to finite element analysis, provided a virtual design environment in which the physical interaction of components were modelled and optimised before proceeding to physical prototypes. “With a programme as extensive as the ZX hoist development, this is an essential prerequisite that allowed thousands of interactions and component configurations to be worked out at much lower cost, and at greater speed than with physical prototypes,” says Pimblett. The 3D models link to the DMS detailing all component specifications and revisions. The DMS is a resource that is linked to component supply partners so that everyone is kept in the loop regarding changes to part configuration, material, manufacturing technique, quality criteria, traceability and material/process certification requirements.

Any changes to component designs are recorded and managed through the engineering change order system. This system ensures that 2D drawings and manufacturing specifications can only be released when they are fully approved. This data is shared with supply partners so that, for example, the supplier of laser cut parts can download information from Street Crane directly into their automated machines in seconds. This removes the dangers of errors arising from the manual input of data and the risks of producing non-compliant components.

The final element in design quality assurance is to prove the performance predicted by models and calculations by physical testing. A special test facility has been established for this that compresses several years of normal service into just a few weeks of continuous operation.

The quality assurance process continues now that hoists have entered production with 100% testing and inspection before shipping. The first is a full load test on the hoist drive train at the certified SWL plus 25% to test all load-bearing components. The second test is an end-of-line test on all motors, brakes, switches, ropes and cast components. This even extends to ensuring all components bear their relevant ID marks, so that in the event of failure in the field, each part can be traced back to source and all other components produced in the same batch identified.

Complete range

At the start of the ZX programme, the plan was to produce a complete range of hoists up to 50t that would maximise the scope for localisation for different markets and customisation to meet end users’ specific needs. Being aware of the need to add value in the destination country, designs were optimised to permit shipping in kit form for local assembly. Modularity and the use of standard components have reduced the build time and manpower requirement substantially to improve distributor margins.

One of the early objections to the idea of local partnerships was that the complete spectrum of user needs would not be met. This meant that partners would still have to depend on others to meet part of their hoist needs. With the completion of the ZX programme, partners will be able to source their total hoist needs from Street Crane.

Andrew Pimblett says: “Requirements above 50t are not that commonplace. Where they do arise these generally require exceptionally heavy duty hoists, often with additional special equipment. The custom engineered VX hoist is designed to meet these needs and is available in capacities up to 200t.”

The substantial investment in the ZX hoist programme could not have been justified for the UK market alone. “It is also probable that a company accountable to anonymous shareholders, rather than a family-owned business like Street Crane, would not have made the investment,” he adds.

The aim has not been to buy into the market with a hoist engineered with cost reduction as the prime concern. The objective of the programme was to create a world product engineered to the highest standards, which by innovations in development engineering and product design could be produced in sufficient volume for world markets to make it both competitive and profitable.

This is a very difficult market right now, but results from the launch of the early ZX models are encouraging. Some leading companies in the crane industry are reporting turnover down 40-50% and are struggling to avoid losses. By contrast, in the first two quarters of 2009, Street Crane recorded only a 15% reduction in sales, but with a net profit increase. Chairman Martin Street attributes this to a policy of continuous reinvestment in the business over many years. “Through state-of-the-art design, value engineering and the use of advanced materials we now make a vastly superior range of cranes and hoists, at lower unit cost and an improved contribution to the bottom line,” he says.

The next step

Street Crane now has a complete range of hoists to take on the rest of the market. The message to existing distributors is that they can source all their hoist needs from Street. The company will also focus on recruiting new distributors, who in the past may not have been convinced that the company could offer the total package.

Further investment in new product development and in production facilities will be made. Plans have been drawn up for a new hoist workshop and the land acquired so that this can go ahead as soon as the economic situation looks right. Likewise, the Z10 development is looking at further refinement and product innovation.