Weite QGX lifting height limiter

1. Industry pain points​

• ​Risk of loss of control of lifting heightWhen cranes, elevators, lifts and other equipment are performing lifting operations, if the lifting gear (hooks, cabins, platforms, etc.) rises beyond the preset safety limit height, a "topping-out" accident is highly likely to occur, causing severe impact damage to the equipment structure (such as the boom, the top of the hoistway), and even leading to disastrous consequences such as wire rope breakage, heavy object falling, derailing and overturning.
• ​Personnel safety threatThe above-mentioned accident directly endangered the lives and safety of the equipment operators and the people around them.
• ​Relying on a single protection is risky:Relying solely on manual observation or primary limit devices is difficult to provide absolutely reliable protection in complex working conditions, especially when operating under fatigue, in harsh environments or during rapid operations, the risks increase sharply.

​2. Solution​

The QGX lifting height limiter is a key safety protection device specially designed to effectively prevent accidents such as lifting equipment hitting the top. The core solution lies in:

• ​Mechanical linkage intelligent triggerThe device is driven by a drum shaft throughWorm gear transmission systemAccurately transmit the number of rotations of the drum (corresponding to the height of the lifting gear).
• ​Precise control of CAM limitThe CAM installed on the worm wheel shaft rotates along with the transmission. When the lifting gear approaches the preset dangerous height (i.e., the drum reaches the set number of turns),The flange of the CAM precisely touches the preset limit switch​。
• ​Forced power-off brakeAfter the limit switch is triggered,Instantly cut off the power source of the lifting (or lowering) mechanismIt also activates the braking system to force the lifting gear to stop immediately before reaching the safety limit position, effectively preventing accidents such as overtopping and over-limit falls.

​3. Core technology​

The high performance and reliability of the QGX lifting height limiter stem from the following core technologies:

• ​Precision transmission system of worm gear and wormThe core transmission mechanism converts the large number of rotations of the drum into the precise small-angle rotation of the worm wheel shaft, achieving an accurate correspondence between the height of the lifting gear and the position of the CAM. It features a stable structure, a large transmission ratio and good self-locking performance.
• ​Multi-contact adjustable CAM limit mechanism​
  • Standard configuration of the deviceFour to eight independent adjustable limit switches​。
  • The position of each limit switch can be adjusted as neededIt can be set arbitrarily within the range from 0 to the maximum number of working turns of the drum (40/80/120 turns)​。
  • Limit switchThe contact form (normally open NO/normally closed NC) can be freely selected according to the requirements of the control circuit​。
  • This design allows users to targetMultiple protections are set for both ascent and descent(For example: warning limit + forced stop protection limit).
• ​Wide-temperature durable structureDesign adaptation​-25℃ 至 +60℃​The wide ambient temperature range ensures stable operation in extremely cold and hot conditions.
• ​Industrial-grade electrical componentsThe key limit switches meet the requirements of industrial environments.Rated voltage AC380V, rated current 2.5AIt can be directly connected to the main control circuit.

​4. Core advantages​

The significant advantages of the QGX lifting height limiter make it a benchmark for safety protection:

• ​Strong versatility, widely applicable​
  • UniqueDesign for matching the number of drum turns(A:0-40 turns/B:0-80 turns/C:0-120 turns) Covering standard and non-standard drums for cranes ranging from 5T to 250T.
  • PowerfulContact selection (NO/NC) and position adjustment functionMake it perfectly compatibleAll kinds of cranes (bridge type, gantry type, boom type), elevators, lifts and other displacement machinery with lifting height risks​。
• ​Accurate and reliable, well-tested​
  • "ThroughAuthoritative type test certification for special equipmentProve that it meets the highest safety standards.
  • The core transmission and mechanical limit structure are stable.The normal service life can reach more than ten yearsReduce maintenance costs and ensure continuous safety.
• ​Easy to install and maintain​
  • The structure is clear and the accessories are completeThe installation process is simple and fast​。
  • ​Years of user practice verification​，​The end user installs it by themselves and resets and reinstalls it laterAll feedback was smooth and positive, significantly reducing downtime.
• ​Multiple protections, safety redundancyIt provides multiple independently settable limit points, allowing for the configuration of redundant protection (such as early warning + emergency stop), which greatly enhances the system's safety.

​5. Practical cases​

The QGX lifting height limiter has been widely applied in the following key areas, effectively safeguarding the safety of equipment and personnel

• ​All kinds of bridge and gantry cranesIn large manufacturing workshops, port storage yards, and steel enterprises, precisely limit the lifting height of the hook to prevent it from hitting the factory building or the lifting gear at the top.
• ​Various types of boom cranes (truck cranes, crawler cranes, etc.) :At construction sites and equipment installation sites, ensure that the hook never exceeds the highest safety point when the boom Angle changes, to avoid the risk of structural damage or overturning.
• ​Elevators and lifting platformsIn the field of vertical transportation, precisely control the travel limit of the car or platform to prevent it from hitting the top of the hoistway and ensure passenger safety.

• ​Application effect examplesFor instance, in a 250T gantry crane renovation project of a large shipyard, the QGX-C type limiter (with a range of 120 turns) was adopted, and two lifting protection limits were precisely set. After debugging, the operation was stable. The limit was accurately triggered and the power was cut off several times before the hook approached the dangerous height, avoiding potential major equipment losses and earning high recognition from the customer.

​6. Technical parameters​

The key specifications of the QGX lifting height limiter are as follows:

• ​Environmental adaptabilityWorking environment temperature range​-25℃ 至 +60℃​​。
• ​Electrical parameters​
  • Rated working voltage​AC 380V​​
  • Rated working current​2.5A​​
• ​Mechanical protection capability​
  • ​Number of limit switches​ ​4 to 8(The specific quantity is determined by model.Adjustable limit switch​。
  • ​Contact status​ ​Normally open (NO) or normally closed (NC) contacts can be selected on-site according to control requirements​。
• ​Matching range of drum turns​
  • ​QGX-A typeApplicable effective working turns of the drum0 to 40 laps(Corresponding to 5T-250T cranes).
  • ​QGX-B typeApplicable effective working turns of the drum0 to 80 laps(Corresponding to 5T-250T cranes).
  • ​QGX-C type:Applicable effective working turns of the drum0 to 120 laps(Corresponding to 5T-250T cranes).
• ​Main dimensions (refer to the illustration) :​
  • Key installation hole spacing (example) :​95mm​​, ​​120mm​​, ​​150mm​​, ​​170mm​(Marked positions in the picture).
  • Installation hole diameter​Ø10.3mm​(Or the aperture is clearly marked in other diagrams).
  • Device depth/thickness (example) :​65mm​(Marked positions in the picture).
  • Other reference dimensions​35mm​(Marked positions in the figure), the main body length is approximately​162mm​Etc. (Subject to the actual marking in the illustration).
• ​Important Notice​
  • The key dimensions shown in the illustration provide an accurate basis for the actual installation positioning.
  • ​The corresponding range of drum turns must be strictly selected in accordance with the model​。