دلو ميكانيكي ذو غطاء صدفي

Product Overview

A mechanical clamshell grab bucket is a two-shell attachment used for handling loose bulk materials such as coal, sand, grain, scrap, and ore. It is commonly installed on cranes, including overhead cranes, port cranes, رافعات جسرية, and ship unloaders. The grab opens and closes through the crane lifting mechanism to scoop, hold, and discharge materials. Also known as a mechanical grab or rope-operated grab bucket, simple structure, reliable operation, and easy maintenance without a separate hydraulic power unit.

The grab hangs from the crane hook. Hoist and closing ropes run through the upper and lower sheaves. The jaws close under their own weight and the pull of the closing rope, cutting into the material pile. Releasing the closing rope opens the jaws for discharge. Motor-driven models use an onboard motor for jaw movement instead of a closing rope. The operator handles the material from the crane without direct contact.

The shells are welded from Q345B or NM400 wear-resistant steel. The head, sheaves, ropes, and hinge pins are sized according to the rated load. Capacities range from 0.5 to 30 m³ and are selected according to crane capacity and material density. Materials include coal, ore, sand, gravel, cement clinker, fertilizer, and grain. Common applications include ports, mines, steel plants, power stations, and waste-to-energy facilities.

للمزيد من المعلومات، اقرأ المقال: ما هي جرافة الرافعة؟

أنواع

How Does It Work?

مواصفات

Mechanical clamshell grab buckets are mainly available in two-rope and four-rope configurations. The rope arrangement affects how the grab is operated and must match the crane’s rope system. Selection also depends on grab capacity, material, and working conditions.

Two-Rope Mechanical Clamshell Grab

A two-rope mechanical clamshell grab uses one hoist rope and one closing rope. The hoist rope raises and lowers the grab, while the closing rope operates the shells. It has a straightforward rope arrangement and is suitable for general handling of sand, gravel, coal, grain, and other loose bulk materials.

• Rope Configuration: 1 hoist rope + 1 closing rope
• Grab Capacity: 0.5–30 m³, depending on the model
• Shell Type: Two-shell clamshell
• Typical Materials: Sand, gravel, coal, grain, and similar bulk materials
• Application: General loading, unloading, and material transfer

 

إرسال استفسار 

Four-Rope Mechanical Clamshell Grab

A four-rope mechanical clamshell grab uses separate hoist and closing ropes for the grab mechanism. The arrangement gives better control of shell movement and is suited to larger grabs and heavier handling work. It is commonly used for bulk material handling in ports, mines, steel plants, and other industrial facilities.

• Rope Configuration: 2 hoist ropes + 2 closing ropes
• Grab Capacity: Selected according to crane capacity and material density
• Shell Type: Two-shell or multi-shell configuration
• Typical Materials: Coal, ore, gravel, limestone, and other bulk materials
• Application: Heavy-duty loading, unloading, and bulk material transfer

إرسال استفسار 

How Does It Work?

A mechanical clamshell grab bucket operates through the crane hoist rope and closing rope. The hoist rope lifts and lowers the grab, while the closing rope controls two hinged shells. The head and sheave assembly transfers rope force to the shells, with hinge pins allowing them to open and close. The grab connects to the crane through a suspension link or similar connector.

• 1. Lower: The crane lowers the grab onto the bulk material with the shells open.
• 2. Close: The closing rope is pulled, bringing the two shells together and allowing them to penetrate the material pile.
• 3. Lift: The hoist rope raises the closed grab with the captured material.
• 4. Discharge: At the unloading position, the closing rope is released, and the shells open to discharge the material.

The mechanical clamshell grab uses the crane’s rope system rather than a separate hydraulic power unit. This configuration is suitable for repetitive handling of loose bulk materials such as coal, ore, sand, and gravel.

مواصفات

مُعامل	Value / Options
SWL (Lifting Capacity)	5.0–25.0 t; 30 t or higher on request
Grab Capacity	1.4–8.0 m³ standard; 0.5–30 m³ customized
Dead Weight	2,640–12,200 kg
Shell Configuration	2-shell; multi-jaw; 6-peel available
Rope Configuration	Two-rope, three-rope, four-rope
Pulley Diameter	315–630 mm
Main Material	Q355B, Q460, NM400, NM500
شهادة	م.م, ISO 9001

• Capacity and Crane Matching: Grab capacity is selected according to material density, required load per cycle, and crane SWL. The grab’s dead weight is also included when checking the crane hook load.
• Rope Configuration: Two-rope grabs use separate hoist and closing ropes for opening, closing, and lifting. Three-rope and four-rope designs provide additional control for larger grabs and demanding handling conditions.
• Shell and Material Selection: Shell configuration depends on the material and working conditions. Q355B is used for the main structure, while NM400 or NM500 wear-resistant steel can be used on shells, teeth, adaptors, and cutting edges for abrasive materials.
• Customized Design: Capacity, shell configuration, rope system, material, and crane connection can be specified according to the crane and operating conditions.

مزايا

تطبيقات

Mechanical Clamshell Grab Buckets are used for loading, unloading, and transferring loose bulk materials in industrial and material handling operations.

الموانئ والمحطات

Loading and unloading coal, ore, grain, and other bulk cargo.

Mining

Handling ore, crushed rock, and other mined materials.

Steel Plants

Charging and transferring raw materials such as iron ore, coal, and limestone.

محطات توليد الطاقة

Handling coal, fly ash, and other bulk materials.

Sand and Gravel Plants

Loading sand, gravel, and crushed stone.

Fertilizer and Grain Handling

Moving free-flowing agricultural and processed bulk materials.

The grab capacity, shell configuration, and rope system are selected according to the material density, required load per cycle, and crane capacity.

To learn more about the specific applications of crane grab buckets in heavy-duty industries, read the article: “Crane Grab Bucket Applications in Ports, Steel Mills, Mining, and Bulk Material Handling”

Mechanical Clamshell Grab Bucket vs. Hydraulic Clamshell Grab Bucket

Mechanical and hydraulic clamshell grab buckets both handle loose bulk materials with two shells. The main difference is the shell opening and closing mechanism. Mechanical grabs use the crane’s rope system, while hydraulic grabs use hydraulic cylinders and a hydraulic power system.

Mechanical clamshell grabs are suited to standard bulk material handling where a simple rope-operated structure is preferred. Hydraulic clamshell grabs are used when independent shell control, stronger gripping force, or more precise grabbing is required.

للاطلاع على تفاصيل حول الاستخدامات المختلفة لدلاء التحميل وكيفية اختيار النوع المناسب، انظر: أنواع مختلفة من دلاء الرافعات وكيفية اختيار النوع المناسب

تختلف الجرافات الميكانيكية والهيدروليكية اختلافًا كبيرًا في استخداماتها وتكويناتها. لمزيد من التفاصيل، راجع المقال التالي: الجرافة الميكانيكية ذات المقبض الصدفي مقابل الجرافة الهيدروليكية ذات المقبض: ما الفرق؟

How to Select a Mechanical Clamshell Grab Bucket

The right mechanical clamshell grab bucket depends on the material being handled, required capacity, and the crane’s lifting system. The grab weight must also be included when checking the crane’s rated load.

1. Material Type and Density: Identify the material and its bulk density before selecting the grab. Coal, ore, sand, gravel, and grain require different shell designs and capacities.

2. Required Grab Capacity: Select the bucket volume according to the required load per cycle and material density. A larger volume is not always suitable if the crane cannot handle the loaded grab weight.

3. Crane Capacity and Hook Height: Check the crane’s SWL, hook height, and rope arrangement. The crane must handle the combined weight of the grab and material.

4. Rope Configuration: Match the grab with the crane’s rope system. Two-rope and four-rope configurations have different operating arrangements and should not be selected independently of the crane.

5. Working Conditions: Consider handling frequency, material abrasiveness, pile depth, and operating environment. Wear-resistant shells and reinforced components may be required for heavy or abrasive materials.

Select the grab based on the material, bulk density, required capacity, and crane specifications. The grab weight, rope configuration, and working conditions should also match the crane.

If you are considering using an overhead crane or gantry crane and are unsure how to select the appropriate grab bucket, see the article: How to Choose a Grab Bucket for Overhead Cranes and Gantry Cranes?

Customization: Mechanical Clamshell Grab Bucket

Mechanical clamshell grab buckets can be designed for different crane systems, bulk materials, and working conditions. The grab size and structure are selected according to the required load, material density, lifting capacity, and operating cycle.

• Bucket Capacity: Selected for the required load per cycle and material density
• Grab Weight: Matched to the crane’s lifting capacity
• Rope Configuration: Two-rope, three-rope, or four-rope
• Jaw Opening: Sized for the material and loading conditions
• Shell Structure: Configured for the type and condition of the material
• Wear-Resistant Material: Options for abrasive bulk materials
• Crane Connection: Matched to the crane hook and lifting system
• Working Environment: Adapted to port, mining, steel, power, and other industrial sites

Provide the crane model or lifting capacity, material type, bulk density, and required grab capacity to start the design.

احصل على عرض أسعار مخصص الآن

Mechanical Clamshell Grab Bucket Manufacturer and Supplier

وي هوا manufactures and supplies mechanical clamshell grab buckets for overhead cranes, gantry cranes, port cranes, and other lifting systems. Custom designs cover grab capacity, dead weight, rope configuration, jaw opening, shell structure, wear-resistant materials, and crane connection. The equipment is used for coal, ore, sand, gravel, grain, and other bulk materials.

WEIHUA has experience supplying lifting equipment to overseas markets and holds relevant quality certifications. Technical support covers grab selection, design, production, delivery, and installation guidance. Spare parts and after-sales service are also available.

اتصل بنا with your crane and material handling requirements for a mechanical clamshell grab bucket quotation.

أسئلة شائعة

خدمة ما بعد البيع

تطورت شركة "وي هوا"، التي تأسست عام 1988، لتصبح رائدة عالمية في مجال التصنيع الذكي في الصين. نحن متخصصون في البحث والتطوير وإنتاج الرافعات الذكية، مع توفير حلول المركبات الموجهة آليًا (AGV). تقدم فرقنا الهندسية والتسليم وما بعد البيع المحترفة دعمًا تقنيًا شاملًا، وحلولًا مخصصة، وإرشادات تركيب في الموقع، وخدمات عالمية سريعة الاستجابة لضمان تشغيل كل مشروع بأمان وكفاءة.

خصص حلول الرفع الخاصة بك

اتصل بنا الآن عبر البريد الإلكتروني: [email protected], ، أو املأ النموذج أدناه.