WALKING EXCAVATORS AND MOBILITY
1 - BEGINNINGS
Edwin Ernst Menzi (1897-1984) (photo 1) and
Joseph Kaiser (1928-1993) (photo 2) invented walking excavator for work on mountain slopes. The use of a classic excavator requires fairly flat and/or soft terrains. The slopes and the rocks can be overcome by walking excavators which give a stable and horizontal rotation of the cab.
Their first excavators in 1966, called MUK (photo 3) was still highly simplified. The rear wheels being fixed, only the articulated arms in front, not hydraulic actuated, allowed to compensate for the slopes.
Subsequently, Kaiser AG, Schaanwal, Lichtenstein, and Munzi Muck AG, Windnau, Switzerland, developed separately excavators more and more advanced with rotating wheeled, first free then driven, rear arm and then hydraulically actuated front telescopic arms, can expand for stability or get closer to the footprint. 4x4 walking excavators use to supplement their boom to move in increments hence the English name : ’Walking Excavators’.
These walking excavators are used in public works. The boom can be equipped with various accessories : buckets of all size, breaker, drill, driver, drilling, mining, slope stabilization, construction and maintenance of ski slopes, installation of anchors bars for soil stabilization, maintenance of terraces of crops. They are also used for forests work on mountain slopes.
They require only a reasonable sized truck for transportation (photo 4) on which they ride on their own.
2 - KAISER
In 2007, KAISER GA, Schaanwald, Lichtenstein, realized a turnover of nearly 60 million Swiss francs.
The company, headed by Markus Kaiser, employs approximately 200 persons in Lichtenstein, Austria and Slovakia. It involved more in ecology, much of its revenue, through the cleaning of drains and water recycling.
The walking excavator Kaiser X4 in 1976 was the first walking excavator of this brand, self-propelled in addition, through hydraulic motors in the rear wheels.
The X4M-TurboMobil unveiled in 1986, followed by the first 4 wheel drive excavator, the classic TurboStar (photo 5) made from 1991 to 1997.
Kaiser offers today a large range of excavators :
2.1 - S1 (photo 6) from 6,9 T and 74 hp.
There is a version for underground work (photo 7) and one for demolition work (photo 8).
The SX 8,5 T (photo 9), successor to the Kaiser TurboStar, has a load capacity and reach of the boom increased.
2.2 - The Kaiser S2 offers since 1998 a new cinematic boom and four wheel drive and steering.
- S2 from 9.8 T,
- S2 4x4 (photo 10) with two small wheels at the front from 10.2 T,
- S2 4x4 Cross (Photo 11) of 10.9 T with 4 equal drive wheels.
The S2 is widely used as a multi-purpose carrier.
Kaiser S2 4x4 Gator (photos 12) of 10.9 T and 157 hp Perkins engine, designed to work in water and wetlands, has leg elevation at the front wheels. Steering is done either by the front wheels or by the rear wheels or all four wheels. It
represents a significant share of exports of Kaiser in the United States.
A note about Schaeff, manufacturer of forklift trucks, which began construction of earthmoving equipment including walking excavators (photo 13) in 1994.
Earthmoving equipment division of that company was bought by Terex Corporation in 2001 before being sold, at least the walking excavators, to Kaiser in 2004.
GSE, multi-seller of construction equipment now successfully markets in the United States Kaiser branded excavators instead of Schaeff.
2.3 - Released in 2007, the Kaiser S3 Allroad (Photo 14), 11.3 T, 157 hp
Perkins engine, is the excavator of superlatives designed for heavy mounted implements. The electronic assistance allows the driver, depending on the activity of the moment, to optimize engine speed and hydraulic activity for reduced power consumption.
The sophistication of the hydraulic system works at pressure of 300 bars at a rate of 190 l / min but the mechanism of translation by a closed circuit produces a pressure of 400 bars at a rate of 140 l / min provided by an axial piston
pump. The hydraulic system requires 200 liters of oil with a tank of 140 l.
One could say that the S3 Track (photo 15) still represents a step forward for off-road capabilities : in addition to the slopes, the excavator can move on the muddy, soft grounds especially for forestry work.
3 – MENZI MUCK
Menzi Muck AG, a competitor of Kaiser AG, followed the same trend and produced more than 5.000 excavators until 2006, date of its fortieth anniversary.
The variety of models produced by Menzy Muck AG since the beginning, whose the 5000 (photo 16) led to the current range which includes:
3.1 - A20 2 ton, 24 hp Kubota engine, the smallest, moves to 2.6 km / h
3.2 - A61 Mobile 7.2 T 4x2, 99 hp Kubota engine moves at speed of 12 km / h
A61 4x4 Plus of 7.8 T (photo 17) with the same engine has the H-Drive translation system, which increases the efficiency of the transmission of 20%. The automatic level control (optional), which was introduced in 2001 on the A71 (no longer
manufactured) and based on the coupling of the hydraulic control system and a
pendulum : the driver no longer address four arms but only one, the other 3 are
3.3 - A81 (Fig. 18) of 8.3 T, 120 hp John Deere, is a 4x2 model of reference to
work as crane.
3.4 - A91 Mobile (photo 19) 140 hp John Deere engine is available in 4x2 and 4x4. The track of the front stabilizer legs ranges from 2360 to 3660 mm in the 4x4 version.
A91 4x4 Plus version, (photo 20) has 4 wheel drive and steering of the same dimensions. It can work in rivers with a depth of up to 2 meters without additional equipment.
3.5 - A111
A 111 (photos 21 and 22), 140 hp J. Deere engine for a weight of 12 T is the
latest model introduced by Menzi Muck and the first to be equipped with an
articulated frame in the axis of rotation of the cab to move laterally the
center of gravity for stability and reduce the turning radius.
3.6 - Special equipment for the range Menzi Muck are shown photo 23 to 28.
4 - EUROMACH AND OTHERS
Euromach, Montichiari (BS), Italy, appeared in 1977. Over 2000 excavators Euromach were built since that date, especially the 6500 (photo 29).
All these machines are sold in France by the multi-brand Company Camuc, Alby sur Cheran, HBI Group, which also sells among other Kaiser walking excavators.
Photos from 30 to 35 show some excavators Euromach.
Brand of walking excavators Kamo (photo 36) and CRS (photo 37) are found
5 - IN THE FOREST
Increasingly, these special excavators allow to working in the mountain forests as harvesters since 1997, to become a mainstay of business builders.
Of course, there has long been special equipment for forest exploitation. They become yet difficult to use in mountains. Of course, there is for a decade more specific forestry equipment such as harvesters Ecolog 4x4, 550C, 16 T for 250
hp or 6x6 T, 580C, 21 T for more than 300 hp (photo 38) equipped with wheel arms hydraulically connected to a pendulum system for working on slopes or the Highlander of the Konrad Society (Photo 39), appeared in 2003, weighting 20
tons for 250 hp, designed for forestry.
There is also tilting cab tracked harvesters as the Timberjack 603 L (photo 40) or harvester 8x8 TimberPro 620 (photo 41) or one fitted with four heavy tracks such as Valmet 911.3X3 ’Snake’ (photo 42).
It appears that these materials, rather heavy and expensive, was not as successful as expected. The walking excavator, lighter, more stable and a little cheaper, but more complex in the arms and the frame, seems better adapted to these extreme conditions and mainly more versatile : forestry work such as felling, hauling and sorting wood on the slopes, earthworks, open new tracks.
However, limitations of use and site organization of these excavators are : slow moving, fueling, very rocky grounds, slopes with rocks and limestone deposits.
The logs must be collected by a skidder. There are no forwarders or carriers for slopes over 30%. Very studied winches and hoists trolleys can carry the trunks above the valleys.
It must still know that the opportunity to work on the slopes is paid, which led some to say that putting more than € 200 000 in the purchase of a walking excavator of 10 T equipped with a grinder is profitable only if it is used only
when other, such as the same price double life CAT 325 crawler cannot venture.
The walking excavator should be reserved only to work on slopes, even if it does not make it work only 500 hours per year.
6 - COMPETITION OF WALKING EXCAVATORS
Computer and hydraulic systems of these excavators are becoming more and more sophisticated and their conduct has a fifty operations so that their control is somewhat related to that of a helicopter. The training of their conduct is very
organized, as well as the ’Olympics Walking Excavators’ where sixty competitors can be separated in front of thousands of spectators and fans from far and many broadcast programs are followed by millions of viewers in countries of West Europe. We have seen excavators compete for climbing blocks 4,5 m high, in which drivers became celebrities for their
expertise and their skill in handling these highly technical equipment.
7 - MOBILITY IN MOUNTAINS
We see that walking excavators present impressive off-road capabilities on slopes and reasonable rocky grounds. We can at this point ask the question :
why not build a mountain transport vehicle based on these excavators since moving in these areas is still a problem ?
Of course there have been over the last 60 years prototype vehicles (See Chapter ’Self-Leveling Vehicles’).
Why this failure ? These vehicles probably did not improve that much mobility : you win a few degrees of slope (and
comfort) but it could just add, as the walking excavator, telescopic sophisticated arms. These improvements, already expensive in themselves, require an electro-hydraulic control even more expensive to purchase and maintain. A ’classic’ tracked vehicle is perhaps better. In difficult cases, it can be created tracks with a bulldozer or... a walking excavator. If the slope increases too, sometimes, there is always the helicopter, weather permitting.
Today (September 2010), only walking excavators and forest harvester, like the Ecolog forest harvester’s type, or the TimberPro tilt cab type seen above are truly designed to move and work in mountains. They are produced in small series.
Pictures comes from Internet : http://www.kaiser.li/en/international/excavators/home/news-scheduled-dates/
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