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Product introduction

De Crab crushing plants provide crushing power for demolition and remediation work.

De Crab plant resembles an arm-robot of large crush strength operating in all directions of a space. It enables to perform demolition work of floors, walls, ceilings and other parts of a building, including work underneath the floor level, around wall corners, on top of ceilings. Similar plants of semi-automatic control system are not manufactured anywhere else in the world.

De Crab produces crushing plants in variable sizes (models). Model number indicates grab jaw span in millimetres. All different models have equal crushing power, but vary in dimensions to assure appropriateness for machines in specific size category.

Most common model is De Crab 500, which is intended for smaller machinery (up to 7t) and is in general most attractive. Machines with average or huge dimensions require accordingly bigger model (700 and up). We also produce model 300 for extra small machinery.

Irrespective of device size, De Crab has several very important and fundamental technical advantages over competitors, which can be divided into five main categories: 
  • mobility
  • autonomous electronic control unit
  • capability of autonomously generate an extremely high working power
  • capability of doing other tasks besides demolishing
  • capability of executing demolition tasks environmentally friendly
For insatnce, if we consider crushing power among small machinery (up to 7t) and devices (200-700kg) only, then reaching comparable power to De Crab plant with other devices can only be dreamed of. Devices with analogous crushing power are many times more sized than De Crab device and with weight of e. g. 5t and they require working machinery minimum of 40t at same task.

Main technical dissimilarities from competitors:

1. The plant consists of a number of links movable with the help of cylinders and a rotor. The characteristics of these links provide the De Crab plant with an ability to move and work in all positions of a space.

The working machinery (wheel and belt loader, excavator) to which the De Crab plant is attached with quick couplers possesses various abilities to move, extended by the abilities to move of the De Crab plant. Device allows grapple to be moved in all possible sides. De Crab plant casing can be hydraulically bent to left, right or behind the corner. At the same time, the rotating case may be turned for 360 degrees in both directions and the grapple attached to the rotating case can be bent, in turn, towards the edge for over 90 degrees. These mobility enables to carry out demolition work also in the premises, where the machine’s mobility is restricted to straight movement only, and to work behind corners. With the De Crab plant it is possible, simultaneously to the crushing of concrete, to cut through the concrete reinforcement by using the three different cutters mounted to the plant.

Such De Crab plant mobility, autonomous electronic control unit and working power grants significantly more work operations, allows to work in various places (with special emphasis on narrow conditions), demolish extra thick and strong materials. Owing to the above-mentioned working options, the De Crab plant can be called an electronically controlled hydraulic robot of high working power and operating accuracy.

All other demolition devices does not have this primary quality. These devices can only be moved onward by machines and device itself can only rotate over its axes.

2. Device movement is granted by autonomous electronic control unit. This De Crab system allows an operator of a working machine to point the work of the machine in all directions of a space and perform the necessary work in any direction.

Control boxes fixed to the working equipment levers with finger nuts are connected to the De Crab plant’s electronic control center by two quick electronic connectors and wiring, both containing four push buttons for control of four hydraulic valves, "+" and "–" movements towards valve piston and then on to hydraulic cylinders and rotor. Such ergonomic attachment of the control panel to the working equipment levers enables simultaneous control of the working machine and De Crab plant.

The plant is equipped with a remote control system connectable by a quick coupling. This, in turn, enables to incorporate the De Crab plant with remote control robots movable by other remote control systems (for example, work under water, work in an extremely hot environment, potentially explosive work environments).

The other crushing plants of the same calibre produced worldwide do not possess their own autonomous electronic and hydraulic control system.

3. De Crab plant is capable of autonomously generating an extremely high working power if necessary and selecting on its own the required amount of working power. When the application of high working power is no longer needed, the plant will immediately terminate its application and restore the hydraulic pressure of the plant to the hydraulic pressure level of the working machine, which will significantly increase the operation speed of the plant.

De Crab 500 plant is capable of crushing a 500 mm-thick steel concrete wall. The experience shows that there is no steel concrete wall which cannot be crushed by the plant. For crushing the concrete elements traditionally used in construction, there is often no need to apply the plant’s high working power, which increases the operation speed of the plant.

The different links movable with the help of the above-mentioned rotor, three hydraulic cylinders and hydraulic valves enable secure working so that the high crushing power of the plant will not be transmitted to the working machine’s casing and beam. The spare valves located within the plant allow the autonomous movement of the grapple so that the entire crushing power of the plant is applied to the grapple only without transmitting it to the working machine’s casing and beam. Thus, neither the casing nor the beam are not subjected to the bending by the plant’s high crushing power.

Demolition plants produced by other companies have a lot less crushing power. For instance, it is not capable of demolishing a 500 mm- thick steel concrete wall, or a concrete wall containing a 30-mm thick reinforcement. This has been repeatedly tried in practice. The equipment is suitable for demolition of soft concrete and brick constructions only.

4. With De Crab plant it is possible to perform work other than crushing work. The features of the De Crab plant robot enable an operator of a working machine to perform work requiring an extremely high position precision of the grapple tips. The plant’s grapple can be mounted in the requested workstation with millimetre precision, and from there on the work may be continued by moving the grapple at a precision higher than a millimetre. Such precision of work is demonstrated in the video introducing the operation of the De Crab plant where an egg is lifted between the plant’s grapple tips without damaging it, after which the work can be proceeded with the egg. It shows, in turn, that the pressure between the egg shell and grapple tips is correct. The video also demonstrates the cutting of a 14 mm-thick steel tube’s side beam and crushing of a large granite rock without difficulty. This, in turn, shows a simultaneous power and accuracy of the plant grapple’s work options.

It is not possible to execute similar tasks with plants produced by other companies.

5. Demolition work is often needed to be performed in an environment where the generation of loud noise, vibration and large amount of dust is not allowed, for example, a building containing working computers and precision equipment / instruments (factory rooms with precision instruments, hospitals, office rooms, departure lounges, markets). In these circumstances, it is not possible to use a hydraulic hammer. Other possible solutions (e. g. diamond drills) are very expensive and slow.

When working with the De Crab plant, the only sound that gets generated is the sound of the working machine engine and falling noise of the crushed details. No vibration nor sound is generated by device. Work is environmentally friendly. The dust produced only relates to the falling of the crushed details and the amount thereof is relatively small in comparison with other possible working methods.

It is not possible to execute similar tasks with plants produced by other companies or solutions are inefficient.

The speed of attachment and removal of equipment mounted in front of the working machinery, including the speed of attachment and removal of the De Crab plant mounted with quick couplers, is often very important for the performer of work. With the help of an adapter, the De Crab plant can be attached to most working machinery using a hydraulic system which meets the requirements on the oil capacity and pressure necessary for the De Crab plant.

The De Crab plant’s working power is affected to a small extent by the oil pressure strength, including the pressure variation in the course of the machine’s work cycle (flowings). The De Crab plant is attached mechanically (quick couplers), hydraulically with two quick couplers of a hydraulic hose and with a quick coupler of an electronic cable. Attachment and detachment are carried out rapidly, it does not take over a minute for an experienced working machine operator to do it. For instance, when working with a wheel loader, the De Crab plant that was performing crushing work is quickly to be detached from the machine and replaced with the quick couplers by a shovel which transports the demolition waste to a waste disposal unit.

Then, the shovel is removed and replaced again by the De Crab plant by way of resuming the demolition work. This is how the cycle repeats itself during the entire working time. Such working cycle enables to use only one wheel loader for working. If the change of equipment was not so fast, a few working machines would be needed for the performance of work – one for demolition and another one for cleaning. While one machine is working, the other is forced to stand still. Standing machine is not profitable and expenses for two machines is still generated in parallel. Working with our multifunctional device leads to a remarkable saving of money.

Calculating return on investment (ROI) can be difficult. As an example of the plant’s productivity may be served experience-based demolition work inside a building, which involves 3 persons working 3 weeks or 45 total working days. Using the De Crab plant, one person completed the work in 8 hours, i.e. within one working day. Work was done on lower floor in Stockholm railway station and the task was to demolish a dividing wall. Job execution can be seen from video by request.

According to above mentioned project, half of work was done by hand and half with De Crab device. Device profitability can be calculated as following:

Manual demolition expenses: Average gross salary for a man on such job was 3900 euro. Employer had to pay 45% taxes to state. So the expenses for one worker per month were 3090 + 1390,50 = 4480,50 euro, which makes 4480,50 : 21 (average amount of working days in a month) = 213,35 euro per day. Task took around 15 working days per person * 3 (persons) = 45 work days. Total salary expenses for the period were 213,35 * 45 = 9600,75 euro.

Demolition expenses with De Crab device: as it took one day, expenses were 213,35 euro. Oil burnup was 2,5 litre/hour, so 8 * 2,5 = 20 euro. Total expenses: 233,35 euro.

Cost difference: 9600,75 - 233,35 = 9367,40 euro. This was achieved only with this one specific task it makes a remarkable amount of device total cost!

In both cases other minor expenses like tools and machinery rental or daily exploitation costs were not included.

Furthermore, working with device is quite safe and risks for work related accidents are greatly reduced since worker is away from demolition spot inside the cabin. Exact opposite to manual demolition, where worker is not safe from larger sharp construction details falling from above.

There are mainly two different sizes of De Crab crushing plants. They are as follows:

1. De Crab-300 is the smallest version of the plant with the grapple’s opening width of 300 mm. The version is intended for attachment to the machinery of extremely small size (for example, mini wheel loaders WILJAM, AVANT, etc.) weighing only a few hundreds of kilos. In this case, the required quantity of counterweights will be added to the back of the loader.

2. De Crab-500 with the grapple’s opening width of 500 mm. It is suitable for working with various machinery, including wheel loaders, smaller and larger excavators, for example:
wheel loaders Bobcat, Gehl and Unc;
small excavators Kubota, Take-Uchi, JCB;
larger excavators Megalac, Caterbiller, JCB;
remote-controlled robots Brock-100, Brock-250, Demec;
telescopic loaders JCB;
large wheel loaders Volvo-50.

It is possible to produce other modifications according to clients needs (different cutters, grapple mechanisms).

It is not wise to attach the device to a huge excavators (20-30t) since these devices sensitivity is not good anymore for our device. For bigger machinery we can produce bigger and stronger devices.

The areas where the De Crab plant has been used have included, in addition to the above-mentioned ones, a number of specific projects:

* the De Crab plant has been used along with other robots underwater by controlling the equipment using television cameras and monitors;
* along with belt machines for squeezing shut oil pipes to terminate combustion thereof by controlling the equipment using television cameras and monitors;
* on fires, where due to the excessive heat, people were not physically able to access the combustion area;
* to save the people who were trapped under the ruins of houses that collapsed during an earthquake. With the help of the plant, dangerous parts of buildings were removed from the ruins without causing vibration and escape routes were opened to the trapped people;
* devices have also been produced for military and metalsmith purpose;
* to crush concrete- and iron details (e. g. fissured bridge edges made of concrete) high up with the help of telescope lifters;
* to lift heavy stuff (e. g. machines, building blocks) high up and/or place  them through holes and to instal heavy details;
* in narrow places in mines beneath the surface, where explosives cannot be used or to crush big stones found during mining;
* to transport stuff considered to contain bomb;
* to cut strong stuff (cables, metal constructions, old metal, bigger furled paper).

For the purpose of performance of all the above-mentioned specific works, grapples of different shape were designed.

Patent applications for the De Crab plant have been submitted in the USA, Japan and 11 European countries.

It is very inefficient to have peripatetic crew with limited power on the job?

Machines are meant to do the job. Effective machine reduces greatly number of required personnel and time spent on job. Save up greatly!

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Demolition and remediation jobs are with high risk, especially indoors?

Risks can be reduced greatly if work gets done by robotics and is controlled by a worker from machines cabin. Protect your workers!

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Rearranging huge demolition devices between locations is costly and consumes a lot of time?

Actually powerful demolition devices can be reasonably sized, transported with e.g. car`s wheelbarrow, attached with machine in minutes and power similar to huge devices is granted. Become mobile!

Seems interesting? Take a closer look!

Demolition or remediation jobs which require high power in narrow conditions like office rooms, cellars, factory rooms, markets etc are often unreachable for machines and therefore infeasible?

Small machinery can often reach such places but don`t have appropriate gear. Get gear and make it possible!

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Some jobs have limits for noise, dust or vibration emitting and therefore difficult to execute?

Demolition and remediation works can be executed with serious restrictions to noise, dust and vibration. All you need is apposite gear!

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