ZX brake closer to the load
A gearbox brake takes the lead in cases where a motor brake is not.
The brake on a traditional hoist is mounted on the back of the motor shaft. In such a design, the brake cannot hold the load if the motor shaft, motor coupling, or motor connection fails.
A unique feature of the ZX hoist is that the brake acts on the first gearbox shaft, so the load is held in place even if the following components fail:
- The hoist motor shaft
- The hoist motor coupling
- The hoist motor connection
If the hoist motor is completely removed, the ZX braked gearbox arrangement will even hold a suspended load.
A braked gearbox offers two advantages when compared to a motor brake design. Firstly, it results in lower operating temperatures for the hoist motor as the heat generated by the brake does not transfer. This will not only increase reliability but also prolong the motor’s lifespan. Secondly, a hoist brake mounted externally allows for quick inspection and maintenance as no need to disassemble the motor cover and fan is required. Although there are other hoist suppliers who may offer additional safety via a secondary braking system, this solution tends to come at a considerable cost.
It is of the utmost importance for crane owners to take into account their duty of care towards employees and understand that in doing so, they are accountable for any possible injury, damage or death resulting from risks associated with cranes and hoists.
This entails making sure that the equipment used is suitable for its purpose and such risk has been mitigated as much as realistically possible, in regards to cases of unintentional release or load drifting.
When you take the decision of proposing the equipment that is required for the system, Al Waha Street Crane shares this responsibility with you proposing the correct fit for the system.
It is, therefore, reasonable to suggest that specifying a gearbox brake will help to reduce the risk of a free-falling load if any of the previously mentioned components should fail.
Does your lifting operation come with an unquestionable merit of safety?
Al Waha Street Crane offers additional safety features over and above a gearbox brake, such as an over-speed switch which automatically applies the hoist brake, secondary braking and safety-rated controls.
ZX hoist gears enhanced reliability
All our gears are within the box. In some hoists, the drum is driven by a final pinion and spur ring outside the gearbox (i.e. open gearing). ZX hoists are designed with automotive standard, hardened and precision ground helical gears, all of which are placed in an oil bath inside the gearbox. This is universally recognised as the best way to provide adequate lubrication for critical gears, resulting in:
- Reduced gear wear
- Enhanced reliability
- Reduced noise emission
- Reduced power consumption
- Controlled temperature rise
All of these points grant better efficiency and a longer service life for the gearbox components.
NOTE: During the Industrial Revolution, large external or open gears were commonly used in power transmission due to their size making it impractical to enclose them in a gearbox or oil bath. Now, thanks to advanced materials and precision hardening and grinding, such gears are no longer necessary as modern production machinery calls for reliability and low maintenance requirements. Open gears still exist today, but being not enclosed by an oil bath means they require frequent grease lubrication. If neglected, this can lead to costly repairs and unplanned downtime.
Access to gearbox saves money and time
Ever seen a car without a bonnet? That’s a hoist gearbox without a lid! It is the responsibility of the employers to make sure that all lifting material is regularly inspected and maintained in a safe and secure condition. In order to ensure the safety of the hoist it is necessary to check the condition of the hoist gears and this should happen as a routine inspection schedule. With the help of a gearbox lid, this becomes easy and quick. But in the absence of one, it is a very time-consuming operation involving dismantling the hoist and hours of downtime. In case you or your service provider are deterred from the inspection of gears, it can also turn into a safety issue because of the difficulty of access or the time involved.
You may be surprised to know many suppliers do not have a gearbox lid!
ZX wire rope hoists feature a gearbox lid, allowing your technician to inspect the gears quickly and easily.
Reduced service time for motor coupling
It saves you time and illustrates our attention to detail in the ZX’s design, a simple inspection port does it all! Employers need to make sure that all lifting apparatus are regularly inspected and kept in a secure condition. To verify the safety of a hoist, it is essential to check the state of its motor coupling as part of an everyday inspection schedule. This is particularly important if designs that use a hoist brake on the back motor shaft are used.
An inspection port simplifies this process, while without it, dismantling the hoist would be necessary, creating hours of downtime and becoming a major risk if access is unavailable or taking too long to carry out such an examination.
Without the process of dismantling, many suppliers refrain from including a means to inspect the hoist motor coupling.
ZX wire rope hoists are designed with a simple inspection port, which enables the condition of the motor coupling to be checked within seconds without any dismantling.
Double Band of rope guide
With experience comes the knowledge that rope guides are an expensive component and regularly at risk of failure on some models of hoists
When unloaded, the stiffness of steel wire rope triggers a de-coiling force which can result in the rope moving through a single-band guide and becoming unseated from the machined scroll – the condition being known as “slack rope”. This can happen during transportation or when the operator lowers the hook block onto an object. It is not always apparent to them as it is often hidden behind covers on the hoist, but if left unattended, it can cause damage to the guide, rope or even hoist itself!
Slack rope occurring is completely prevented by ZX design
A unique rope guide system on the ZX hoist prevents slack ropes from developing on the drum by utilizing two bands. An outer band seats around the rope to ensure it is guided into the correct drum scroll and prevents decoiling. The rope guide is constructed from tough, wear-resistant synthetic polymer designed to last the lifetime of the hoist and is machined so that both parts can be easily removed and fitted during rope replacement.
We guarantee you there are not many suppliers who include a double band.
NOTE: Routinely jumping to conclusions that operator side pulling is the cause of a rope guide’s failure can be avoided. In our experience, “slack rope” is a far more common cause of failure in those hoists with single-band rope guides.
Due to their limited flexibility before breaking or permanently distorting, cast iron rope guides have long been considered the least resistant to failure in side pulling, followed by steel rope guides. Steel wire rope strands are more likely to be permanently damaged by cast iron and steel rope guides because of their characteristics.
The material used for the ZX rope guide has been carefully selected for its tough, resilient, self-lubricating properties, all of which are designed to flex and work with steel wire rope rather than wear or permanently damage it.
Enhanced hoist drum safety
Presenting to you a fundamental safety feature unique to our ZX wire rope hoists.
A continuous shaft runs through the centre of all ZX6 and ZX8 hoist drums and a purpose-designed “retention flange” sits at either end. This arrangement ensures that: If the drum fails, the rope and load will be retained by the shaft. If the shaft fails, the retention flanges will maintain the drum with the load and rope.
We guarantee that you won’t be able to find any other manufacturer offering our level of hoist drum safety as standard.
This “one-fault-safe” design was developed specifically for Al Waha Street Crane to offer lifting solutions for nuclear handling applications and other environments involving handling hazardous loads. Our complete range of ZX6 and ZX8 models now comes with this enhanced safety feature as a standard feature.
Additional overload protection-ZX hoist
A wire rope hoist’s overload device or rated capacity limiter (RCL) measures only the load on the rope(s) or uses motor current to calculate the load. In addition, motor current can vary for external reasons, as rope load cannot be detected when it is impeding the rotation of the hoist drum or gear.
An innovative design of RCL is incorporated into the ZX hoist, forming a torque arm between the hoist gearbox and the hoist frame. In addition to the load on the hook and any rotational impedance, this measures the total load transmitted by the hoist mechanism. Among the additional loads detected by the ZX RCL that are not detected by rope overloads are brake release failure and some gear or bearing damage.
Its operation is highly predictable and has been demonstrated in tens of thousands of installations worldwide.
SG trolley reduces dead weight
To balance the weight of the hoist mechanism, traditional single girder hoists require a counterbalance on one side.
A reaction roller runs on the underside of the crane beam on the ZX single girder hoist trolley, eliminating the need for a counterweight.
A reaction roller:
- Cuts down the overall weight of the hoist and the crane
- Reduces the required power for both trolley and travel motors and thus dramatically improves drive efficiencies
- Increases trolley stability
- Ensures increased traction by creating and keeping constant contact between the drive wheel and runway beam. This can be particularly problematic on rolled I-beam sections
- Alleviates trolley control
- Provides a more compact and lighter hoist solution that helps save packing and shipping costs