Untitledby
Canoga Park, CA 91304
Allan Rosman, president of Dynamic Hydraulic Systems, Inc. and inventor of the Dynahoist, holds degrees in mechanical, civil and industrial engineering. He is a graduate of the University of Chile and the Madrid, Spain School af Industrial Engineering. In addition to Spanish, he speaks Italian, French and German. His experience includes design and management of a wide range of engineering projects throughout Europe and South America including food processing and industrial equipment manufacturing and gondola and chairlift cableways for passenger transportation.
He designed and built one of the first cableways to use a hydrostatic transmission on which he holds both Spanish and American patents.
In 1979 his work on a hoisting project led to concept~on and patenting of the Dynahoist. This was followed by several years of development and a successful 10-month prototype test. First major Dynahoist installation was a container crane for the Spanish National Railway which provides a six-fold improvement in productivity over the conventional crane it replaced.
Dynamic Hydraulic Systems, Inc. was incorporated in the United States in 1984 in partnership with a large New York-based publicly-held firm. First major installation of the Dynahoist in the United States wi11 be for a specialized dredging requirement. Mr. Rosman has nine patents pending for different Dynahoist applications and is applying the syste~ to forklifts, drilling rigs, container cranes and other vertical hoisting equipment.
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INTRODUCTION
The DynaHoist is an industrial hoisting system that uses a "phantom" no-mass counterweight to significantly increase productivity of cranes, derricks, dredges and other lifting equipment. It can substantially increase load lifting speed and handle a given load with up to 90 percent less power than conventional hoists.
Without winches, brakes, drums and other heavy rotating machinery, the DynaHoist costs about half that of conventional hoisting systems for most installations.
In the DynaHoist, the "phantom" counterweight adds stored energy to the hoisting task, making it possible to lift larger loads faster with smaller diesel/gasoline-powered engines or electrical motors, with corresponding decreases in energy costs.
Heart of the DynaHoist is the no-mass counterweight, essentially a hydraulic accumulator charged with nitrogen at high pressure.
With primary lifting force provided by the stored energy of compressed gas acting on the hydraulic fluid, an electrically or engine-driven hydraulic pump acts as a power integrator, adding a small amount of additional power needed to lift the load. Energy is returned to the accumulator when the load is lowered.
Lifting is accomplished by one or more traction cylinders which resemble conventional hydraulic cylinders but have been specially designed by Dynamic Hydraulic Systems, for durability and in-place maintenance without disassembly.
With multiple reeving, the DynaHoist principle has been applied to lifts of up to 400 feet with loads of up to 600 tons and load speeds of up to 300 feet per minute.
The invention was first applied to big scissor lifts without any inkling about the number of markets and advantages the DynaHoist can offer.
To our surprise, the counterweight concept, which we thought was applied in every industry, was only so in the high-rise elevator industry. Every market and industry we went into was using "total power". Finally, we also discovered that the main markets, the open mind and the human resources were in the U.S.A. So two years ago, a company was formed here, Dynamic Hydraulic Systems, Inc. and patents were applied for. We are backed by National Patent Development Corporation, an American company located in New York City.
From this point on, we have developed the engineering, marketing, research and technical details for several applications; one of which is dredging.
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DESCRIPTION OF THE DYNAHOlST AND
COMPARISON TO STANDARD DREDGING HOISTS
1. BRIEF DESCRIPTION OF THE DYNAHOZST
The DynaHoist consists of three ! major components:
The first component is the dynamic counterweight with an insignificant total weight, stores large quantities of hydraulic fluid under pressure and produces the same effect on a crane as a massive moving counterweight balancing the hoisted load.
The second component is the power unit. This independent unit consists of an engine or motor directly "onnected to a hydraulic system with power integrator, valves, safety interlocks and a complete diagnostic system. The hydraulic system replaces the variable speed devices, such as torque converters or DC generators and all brakes and clutches normally found in a hoisting system. The hydraulic system is always in a neutral mode when starting the drive unit, therefore, a simple AC squirrel cage motor or direct coupled diesel engine and can be started under a no-load condition.
The third component, is the linear motor. lt is a single- acting traction cylinder or cylinders! of standard lengths and diameters sized to give the proper line pull and lift height required to meet customer requirements. Through multiple reeving, lifts up to 400 feet and 600 tons are possible with load speeds up to 300 f.p.m.
These components act basically as a counterweighted system, exactly as in an electrical elevator. The loa<i is connected to the pulling cage: the pulling cage and the counterweights are connected to the power unit in such a manner as to make the counterweight equal in value to the empty weight plus half of the maximum live load. Therefore, the maximum load to move will be only half of the live load, instead. of the empty weight plus the live load. The practical arrangements are slightly different, depending basically on the load time curve of each specific application.
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2. THE WINCH VS.THE "PULLING CAGE" OF THE DYNAHOIST SYSTEM
Description of a Pulling Cage See Drawing No. B 1247!
2.1
The traction cylinder, normally around 23 ft. stroke, is mounted together with reinforcing pipes: these pipes are used to take the extra. loads created by the reeving and to contain the nitrogen of the dynamic counterweight. Cylinder length is between 40 to 60 feet; reevings can vary from 2/1 to 12/l.
Reeving2.2
The reeving is in reverse to the normal reeving arrangements used in hoisting. The main objective of a conventional hoisting system is to achieve a desired line pull and line speed. However, necessary high drum speeds can often result in maintenance problems on clutches, brakes and other moving parts.
For the typical DynaHoist, standard cylinders from 5 ton to 600 ton capacity and 24 feet in stroke are available providing up to 300 ft. of lift. 12/1 amplification appears practical. 'The first goal is to get the proper total travel. With the reeving determined, the load will define cylinder capacity.
Note that there is no fleet angle to consider and that the fastest cable is the one going to the load; use of double grooved sheaves and pulleys is very practical and double cables makes it possible to use lighter cable and smaller pulleys. lt also adds a new dimension of safety since loss of one cable does not mean losing the bucket.
The arrangement indicated above has a far higher efficiency when compared with a direct winch system such as in dredging!.
Acceleration and Kinetic Energy2.3
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The DynaHoist counterweight is described as "phantom" because it acts as an actual conventional counterweight, but has no mass.
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In a standard hoisting system, heavy equipment rotating at high speeds include:
L. Prime Mover 2. Torque Converter 3. Gear or Chain Speed Reducers 4. Shafts
5. Clutches
6. Brakes
7. Sheaves
8. Drums
9. Cable
Some of these components in a diesel prime mover are rotating all the time and represent a portion of the energy available when a sudden increase in the load occurs such as when the closing line is ready to lift the bucket at the end of a closing cycle. The used kinetic energy at this point is several times the energy needed. to lift the load at full speed, so the stress that occurs on the cable is so great, hoisting speed must be limited and the boom and crane are severely derated.
In addition, the kinetic energy resulting from the rotating machine parts is such several times the kinetic energy of the load! that the acceleration will be slow and time is lost before hoisting reaches nominal speed.
These limitations also hold when stopping the rotating parts in terms of time needed and energy lost.
With a totally different principle, the Dynalioist has the following characteristics:
The kinetic energy involved in starting and stopping is only the energy related to the load. The cylinders and sheaves run at very slow speeds /4 of the load speeds or less! and for that reason their kinetic energy is almost immaterial. The counterweight, having no mass, has no beari~g on the kinetic energies involved.
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The system reeving and configuration acts as a spring, relieving any overloads due to changes in speed or load. The oil compressibility has a large effect due to the long stroke of the cylinder and the amplification on the load due to the reeving.!
b.
The closing line speed has no limitations in dredging; when the closing operation is finished, the speed is automatically reduced by the parallel application of the holding line and the spring effect will cushion any possible shock load left.
a.
Accelerations are no longer limited by shocks and power available.
b.
See Drawing No. l080!
2.4
A typical pulling cage will measure between 40 to 60 ft. long and the weight will depend on the pulling capacity; a 4/1 system with an 80 ton cylinder {total end pull 20 ton! vill weigh nearly 7500 lbs.
Nidth and depth are very small, so that a pulling cage could be mounted above and/or under the boom without creating undue stresses on the boom.
The power unit is connected by hydraulic lines and is a small compact, unitized unit which can be mounted outside the machine room, leaving the winches available for other uses.
The counterweight is only a 40 ft. pipe which could stand anywhere near the power unit, as alongside the A-frome of a crane or the mast of a derrick.
Load Sharing and Automation2.5
Applied to dredging the DynaHoist requires three specific capabilities not encountered in other applications:
Two independent pulling cages in order to handle the holding and closing lines.
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For these two reasons, the DynaHoist can bring two important benefits to dredging never before thought possible:
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b. One pulling cage has greater reeving to handle extra travel of the closing line.
A bottom detector so that the system will stop instantly when the load reaches the ground. Dredging is the only application where the bucket hits bottom at full speed.
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Load Sharing:
Since the two pulling cages are connected to the same load and. with the same pressure, the DynaHoist provides in-built load sharing. Because of this built-in load sharing, the cables could be smaller than a conventional system.
Ease of Operation -- Automation:
This eliminates the clusters of controls needed for conventional cranes and is already very near total automation for some of the dredging applications.
Structural Effects of the Pulling Cage2.6
Adding a DynaHoist pulling cage to an existing boom has two major effects on the boom itself.
a. Total boom weight
b. Stresses on boom and boom securing pins
Thus addition of the DynaHoist pulling cages will require some new calculations with respect to the total weight of the system and the required supporting structure as well as with respect to the relocation of the weight of the load on the boom. These calculations are quite straight forward and are incorporated into the various proposals and designs we prepare.
If there is no existing boom and we are designing a DynaHoist boom arrangement as a new project, the
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The system has already two important automation factors built-in; the ground detector and the load sharing. Once the bucket is closed, one or two levers control the following: speed, direction, braking, clutching and closing line operation.
DynaHoist properly sized and spaced, are incorporated as part-length of the boom structure. They are much stronger than a conventional boom section. Several of our current desi.gns are based on this type of proposed system.
3. THZ DYNAHOIST COUNTZRWZIGHT
3.l
We are not aware that a mechanical mass counterweight is in actual use in any crane used in dredging, with the exception of' small counterweights used as taglines! let alone anything resembling our "phantom" counterweight. Thus, we believe we are bringing a truly un»que and innovated "first" to this industry.
Dredging is a very interesting appli.cation of the DynaHoist concept for two main reason;:
Weight of the bucket or fixed load is very high percentage wise, when compared with the total load easily over 50 percent!. Our counterweight makes the DynaHoistinstalled power independent of that load," in a conventional crane the winch has to carry the total load. The savings in installed power are substantial.
a ~
The use of the DynaHoist counterweight concept will substantially decrease the "cost of hoisting speed", radically charging the cost factors applied to a typical dredging operation.
b.
The counterweight can be vari.ed hy simply bleeding off or adding nitrogen. Thus, changing bucket size is no problem and requires no change in reeving.
c ~
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A normal winch applied to dredging wi.ll necessarily be a total power device, meaning that the power applied to the machinery wil» be:
Power = Speed x total load/eff.
The efficiencies involved in producing the maximum power needed as opposed to power consumption! are quite low because so many components are involved....namely: prime mover, torque converter, gearbox, secondary transmission, drum, cable, sheaves, as well as kinetic energy.
The total efficiency for hoisting is, authorities in the field tell us, no more than 50 percent, for the DynaHoist again related to power installed and not to power consumption!, it runs more than 75 percent.
Our basic formula will on the other hand, be:
Power = Speed x 0.5 x live load/eff.
However, in many dredging applications the main advantages will be in achieving higher hoisting speeds using the same power source, thus translating the DynaHoist advantages from power savings to a greater number of hoisting operations per hour.
Energy Consumption Savings Analysis3.3
At equal speed and number of cycles per hour a simple calculation shows about 60 percent savings in energy consumption. This should be related to the number of hours the dredge is used per year to assess any investment on a retrofit basis. If the loads handled are, in fact, less than the maximum loads predicted, the savings could be higher since the counterweight characteristics can be easily adjusted to the optimum efficiency for any job.
4. PRIME MOVER AND TRANSMISSION COMPARISON
Dimension and Nature of the Prime Mover.
As already indicated, the size of the prime mover will be radically changed, for the same end speed; in practice, there will be two different analyses:
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In practice we can expect that for the same speed with a diesel engine or an electrical motor, the DynaHoist will require 75 percent less installed power than a traditional winch system.
a. Using a diesel engine as prime mover..
The diesel will be fitted with a constant speed governor and directly connected to the DynaHoists pumps. No speed reducer or torque converter will be needed. Both functions are built-in to our hydraulic system.
b. An electric motor as prime mover
Conventional dredging cranes zequire 0he electrical motors to be a wound zotor or DC motor due to the shock loads and high starting torques typical in dredging applications.
Clutch and Brakes
With the DynaHoist, there is no need for the conventional clutches or brakes. When its single contzol lever is moved to neutral, the DynaHoist system acts as a clutch and brake at the same time and there will be no need for auxiliary compressed air for control.
Due to the unique design of our hydraulic circuit, there is a second level of brakes in the system, what we call safety bzakes; these brakes are on every time the hoisting stops and will also act automatically when any failure occurs in the system, including the failure of the operational bzakes.
These brakes and clutches az'e of a totally different nature than the ones normally used and DO NOT require any maintenance or replacement of parts because there are none.
Speed Limitation4.3
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However, with DynaHoist, the electrical motor starts unloaded and is running at full speed before getting any load; a squirrel cage electrical motor without complicated starters or speed control can be used; the horsepower of the motor will be about 66 percent less than motor needed for the conventional system, far the same speed and load.
The DynaHoist has no speed limitations except those related to the increase in productivity versus increase in cost. The cost of increasing the speed is lower than in a conventional system.
Cable Travel Limitations4.4
That is one of the main limitations of the DynaHoist in the pulli.ng cage version. The amplifying reeving is not practical over l2 times l2x24= 288 ft of travel! or at 576 feet if a double pulling cage is used. However, we have a winch version for fast, long hoisting applications.
The pulling cages limitations in total cable travel does not not appear to be a problem in dredging, where lifts of between 60 and 180 feet appear to be the limits.
Speed Control
4.5
With the proper operator actions on the clutch, brakes and accelerator control, a conventional hoisting system starts pulling the closing line up. One hand lever does the job on the DynaHoist, with automatic maximum acceleration.
Lowering the Load
Power Transmission4.6
A conventional system requires several heavy machinery components, the last of which is a slow winch pulling a cable; this impacts the weight, cost, efficiency and maintenance.
On the other hand, the DynaHoist combines a specialized cylinder with a volumetric pumping
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Releasing the brakes and clutches and controlling the retarder, if any, will make the load descend on a conventional system. The single hand lever on the DynaHoist will lower the load at any speed up to the maximum rated speed with built-in maximum acceleration.
device to transform the rotational power of a prime mover to a linear pull we call the cylinder a reversible linear motor!. There is only one intermediary and a very efficient one namely, the hydraulic oil.
Heat Creation and Cooling4.7
The DynaHoist system always has on line three sources of power elements either providing or using energy counterweight, the load and the prime mover: there is no need of a heat sink whatsoever in the system; the only heating source for the system is the efficiency itself as compared with the brakes and retarders acting as heat sinks for the potential energy lost in the descent of the bucket.
For this reason the DynaHoist system can be described as a "cold" system when compared with the most traditional systems. No special cooling is neccesary.
Shock Load Analysis and Description4.8
On the other hand the DynaHoist has a totally different effect:
The length of stroke and reeving causes the load to act as if the load were hanging from a huge spring, damping the loads created by high acceleration.
a ~
When closing the bucket, the slightest overload above a set point triggers the system to a lower fluid flow and at the same time causes both closing and hoisting lines to work in parallels Thus, the initial lifting of the
b.
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The worst shock in a conventional dredge crane is produced when the bucket is near closing and the winch begins to haul the whole bucket up. Due to the high kinetic energy of the machinery, the peak load produced on the cables is substantially higher than the nominal capacity. This must be considered when selecting and sizing the prime mover and other machinery, as well as derating the crane capacity, and increasing breakdown and maintenance costs.
bucket is very smooth without the peak loads and stress of conventional systems
5. SAFETY AND MAINTENANCE COMPARISON
Parts to Maintain, Nature and Weight
Maintenance cost is an important advantage of the DynaHoist. There are so few moving parts.
--A prime mover...less than half the horsepower of a comparable winch installation.
--A squirrel cage electrical motor instead of wound rotor or DC motor and less than half the power. The electrical controls are simple and rugged.
--Counterweight...no moving parts
--Pulling cage...basically a hydraulic cylinder with two seals to be changed every 2,000 hours and designed in such a way that there is no urgency even if they are leaking. There is no need to dissasemble the cylinders to change the seals.
--Two hydraulic pumps with no routine maintenance, able to operate more than 10,000 hours Bl0 life or more They are easy to replace, relatively inexpensive, and very light weight.
--Change filters and oil every 2,000 hrs.
A complete diagnostic panel is built-in.
Compare the DynaHoist with the following parts to maintain and grease evexy day in a conventional crane.
Torque converter Cooler for the torque converter oil Primary gear box Secondary gear box Clutches
Brakes Air controls
Motor overload
End of stroke safety stops both directions! Overload control responds to as little as 10 percent! Filtration status Counterweight failure Starting motor under load safety Dynamic braking capacity Static brake Automatic safety actuation! Oil level safety
THE SYSTEMS STOPS AUTOMATICALLY WITH ANY
FAILURE
6. STANDARD HYDRAULIC HOISTS AND DYNAHOIST COMPARISON
A standard hydraulic hoist system works basically with a hydraulic motor attached to a winch in one of two configurations: high speed motor and gear box or a low speed motor in direct connection to the winch.
To make things worse for the traditional hydraulic hoists, there is tremendous heat created by the very nature of the system. The oil is used as a heat sink for the potential energy lost when the load is descending. Sometimes the hoists need power even when the load is coming down, adding heat when there is already plenty. Heat variations in hydraulic systems are killers in two ways; one is the effect on the hoses and fittings and the other is the heat shock on the hydraulic motors.
For these reasons standard hydraulic hoisting systems are generally limited to light duty applications, and slow speeds.
As you already know, the DynaHoist is totally different and it is not limited to light duty applications. On the contrary, it can and should be used in very heavy duty applications. Dredging, which is considered a very heavy duty application is an ideal application for the DynaHoist.
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Unfortunately there is no comparison possible in reliability and easy maintenance between a cylinder and a hydraulic motor.
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7. BOOM HOIST APPLICATION
See Drawing No. 1,086!
Tremendous advantage can be gained in applying the DynaHoist to a boomhoist.
The winch is completely eliminated or can be used for other purposes.
The inefficiency of the present boom hoist is legendary, due to the high number of parts of line required. The DynaHoist can easily increase boom speed 5 times at a fraction of the conventional hoisting system cost and with less power than the one used in conventional installations.
8. THE ECONOMICS OF THE DYNAHOIST
Every true and usefull innovation can have only one bottom line and this is the economics; not just small savings but the ability to pay for itself within six months to a year considering all the factors involved: initial investment, power savings, installation savings, maintenance savings and increasing productivity.
Initial Investment8.1
Applied to dredging and without considering secondary investment, the cost of a DynaHoist will be between 30 and 60 percent less than a conventional hoist for the same speed and load.
Secondary Investment8.2
The savings here are difficult to assess because there are so many different cases. However we can point out:
Installation of the DynaHoist is very simple; the pulling cage could be installed on the boom or become the boom! and the power unit is small enough to be located anywhere. In a conventional system, installation of a bigger winch outside the machine room because of lack of space requires a large
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For example, the DynaHoist counterweight can mimic the variations in tension due to boom position, with significant savings in installed power requirements.
investment to be made. The costs can be staggering, even higher than the total cost. of the DynaHoist itself.
Where electrical power is involved, the DynaHoist does not require more installed power for the increased capacity. A connventional system will require an increase in installed power which sometimes can even involve the main generator, power transformers and electrical lines.
Power Consumption8.3
We estimate DynaHoist power consumption to be about 50 percent less than a normal dredge crane. This can be misleading, however, because normal productivity of the DynaHoist-equipped dredge will be much higher even at the same rated speed; also the main objective in some applications is to increase the working speed substantially. Thus, the comparative number will not tell the whole story.
Maintenance Savings8.4
For all practical purposes, it is our opinion that the hoisting side of the maintenance bill will go to almost nothing when compared with conventional hoisting machinery.
Ease of Operation8.5
Instead of a cluster of controls, the DynaHoist has just one or two control levers and can provide the capability for total, simple and inexpensive automation. The DynaHoist makes the operator more comfortable and enables him to do a better job with less effort and fewer mistakes. The DynaHoist has a ground detector which can eliminate raising empty buckets
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An added bonus with the DynaHoist, is that, in a retrofit, existing winches can stay where they are for stevadoring or pile work and the DynaHoist can handle the dredging application.
9. CONCLUSION
To anyone who cares to listen, we could prove that the DynaHoist offers a smoother, faster, easy way to handle a dredging system and an enormous savings in first investment and operating costs.
In spite of these advantages, they are never enough to make a system a success; engineering history is plagued with examples showing the influence of the enduser, the completely impossible task of making an OEM use a system not originated at his company, the influence of a maverick company in the development of totally new products, etc.
We think that three examples of this engineering history are relevant to the future of the DynaHoist:
THE INTRODUCTION OF THE AC DISTRIBUTION SYSTEM OVER THE DC
Thomas Alva Edison invented and developed the light bulb and went further up to the creation of the DC distribution system, finally creating the General Electric Co. before the end of the 19th century.
Another inventor, Nicola Tesla, invented the Tesla coil, or transformer and the whole concept of an AC distribution system so that the generators could be at any place, the power being transported at high voltage and low losses, making possible the power dams and the big generating stations, far from the industrial and residential areas.
Mr. Tesla became associated with George Westinghouse to form the Westinghouse Electric Co. After 6 months of the presentation of the AC system, every electrical engineer in the country knew that the DC distribution system had its days numbered. In spite of that knowledge it took the Westinghouse Co. more that lO years of deadly fights to overcome General Electric resistance and at a very high price; the forced selling of their patents to General Electric.
Conclusion: Any monopoly can stop progress.
THE DIESELl ZATION OF THE RAILROADS
The development of General Motors in the 30's of a lighter,
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faster two stroke diesel engine made possible the development of the diesel electric locomotive. However, the steam locomotive industry as a whole considered the diesel a "fad" in spite of all the engineering data available
At the prodding of Ralph Budd, president of Burlington Railroad, General Motors finally went into the business diesel electric locomotives!. Within the next 6 years every railroad in the country went to Diesel; the steam locomotive manufacturers faded away and the railroads reaped tremendous economies from every possible angle...speed, operating savings, maintenance, personnel, automation, etc.
Conclusion: The end user is sometimes the key to progress
THE REPLACEMENT OF THE VACUUM TUBE BY THE TRANSISTOR
The Bell Labs invented the transistor in 1948; when they tried to introduce it at its logical application, the radio and TV industry, the majors at the time, General Electric, RCA were inmediately convinced of the advantages but were looking at the transistor as a "cheapy" gadget. They predicted the initial use of the transistor about l.975, when it vould be about ready for them.
Conclusion: A progressive company is interested in new products.
Wealth comes only through innovation and innovation is the business of America. Let' s keep it that way!
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A small company, unknown at the time called Sony, read about the transistor and although they vere a brand new company and not even in consumer electronics yet, came to the USA and bought a license for the transistor for $25,000. The rest is history. Within the next five years there was no tube radio manufactured anywhere and Sony and other Japanese companies dominated the market. And as of today, we understand there are no manufacturing facilities for radio and TV in the continental USA owned by an American Company.
ABSTRACT OF DYNAHOIST ADVANTAGES APPLIED TO DREDGING
For the same speed and capacity less than 50 percent of a conventional system cost.
No need for additional space to retrofit for higher speeds and loads.
2.
The DynaHoist eliminates all of the rotating inertias from the driveline, and the frictions involved in all of this machinery. These consist of clutches, brakes, drums, drivegears, torque- converters and engines.
3 ~
5.
Since no large inertias are involved, automation of the dredging operation is comparatively simple.
6.
The holding and closing lines share the load, enabling use of smaller cables than a conventional system. This reduces the cost of the wire ropes and the labor required for rereeving.
7 ~
Due to the use of a dynamic counterweight, the power requirement is much less than would be on a conventional operation. The savings in fuel alone are substantial.
B.
Since the DynaHoist replaces two of the existing winch drums, in the unlikely event of a breakdown or a time-consuming maintenance requirement, the two existing drums can be used as backup with the derrick's normal reeving system.
9.
The DynaHoist is operated by two levers instead of the cluster of hand and foot controls required by the conventional equipment. This reduces operator fatigue and lowers the possibility of errors. In your case the operator's choices are: a! up or down and b! bucket open or close. All other decisions will be automatic.
10.
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The spring effect of the DynaHoi.st automatically dampens shocks.
Because the DynaHoist has effectively, one moving part, the stocking of spare parts is greatly reduced.
We use only the best materials' Stainless steel shafts, the finest seals and fittings and an effective paint system, just to mention a few.
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DYNAHOIST POWER INTEGRATOR
DynaHoist uses single lever control compared to multiple controls needed on. conventional hoist
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DYNAHOEST PROTOTYPE CI AiISHEI.L HOEST
Prototype used to demonstrate DynaHoist operation. Power integrator with single control lever and diagnostic panel is at lower left; dynamic counterweight is cylinder at right of boom.
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ASSOCIATION ANNUA1 MKETING