PNEUMATIC TRACKS

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Why not marry the advantages of wheel and track ? The pneumatic track is the answer : integrated suspension in the elastic element, higher speed than metal track, better load distribution.

The first practical model comes from the Russian scientist N. S. Vetchinkin in 1927 and in the 30s, N. I. Gruzdev addressed the problem but abandoned for lack of natural rubber.

They found many patents. There are four categories of pneumatic tracks (photo 1).
From the standpoint of interest, only tracks of V. T. Sheppard in the U.S. and especially G. Bonmartini in Italy are of practical interest.

1 - A realization came from Count Giovanni Bonmartini, Aosta, Italy, who studied a landing gear for tracked amphibious light aircraft since 1930. In 1949, a 65 hp Piper was also equipped with a tire tracked landing gear (photo 2) studied in collaboration with Superga of Pirelli Group. The track consisted of an annular tube of sheets of gummed cord resting on two rods, all surrounding an air tube wrapped by a rubber surface. According to R. M. Ogorkiewicz (The Engineer's July 21, 1961), the aircraft landed normally in a field dotted with small cuts that would have proved disastrous with a classic wheel train.

Bonmartini also adapted a tubular caterpillar to a 18 hp and 1.3 t Lombardini tractor, the 'Castoro' (photos 3 and 4) that demonstrated its ability to the First International Conference ISTVS (International Society for Terrain-Vehicle Systems) in Turin in 1962. A maximum speed doubled, caterpillars reliable and a few vulnerable, quickly changed if necessary and silent, that's what seduced. A small pump lubricated the inner surface of the caterpillars.
This pneumatic caterpillar tractor was sold commercially, but unfortunately they do not know the outcome of sales. Despite limitations in traction compared to a conventional track, the system had a real future in agriculture where the minimum land degradation is required.
G. Bonmartini conceived also a multi-track tire (photo 5).

2 - A semi-pneumatic caterpillar (photo 6), whose model was built in 1965 on capital by Mr. Okada, Japan, presented itself as a kind of wheel with bearing surface increased ; the sides of the track were sealed using flexible diaphragms to prevent intrusions and keep lubricant required. Increased tensile strength and decreased ground pressure was interest from a conventional wheel.

3 - Gregory Miezcyslaw Bekker, the father of the Theory of Off-Road Locomotion filed various patents including a 'mobile support' (photos 7 and 8) in 1963. It was also a waterproof track and immersed in oil. An outer band driven slipped on a tire-shaped triangle whose section was narrower above than below. In fact it is always needed to increase the bottom because in the upper part are the brakes and transmission. There is no known prototypes.
Similarly, D. O. Yoe proposed in 1963 a patent for pneumatic track (Photo 9) triangle shaped.

4 - Inflatable compartment tracks interconnected or not

In 1961 was built by Ling-Temco-Vought, Inc., Michigan of Chance Vought Corp., Dallas, Texas, a test model of scaled vehicle, the Scaled Test Bed (photo 10). The idea was new in bags attached to a band and interconnected. Tested with different bag configurations (photo 11), this connection allowed a bag to absorb an obstacle by deflation, which transferred the air to the next bags. In fact, the model PATA (photo 12) (Plenum Amphibian Air or Pneumatic Tread All Terrain Amphibian) scale 1, which appeared in 1965 did not include this too complex provision.

PATA had only two wheels and no track suspensions, the latter being carried by air bags that allowed to ride on roads and terrain to fairly high speeds (40 kph) and smooth, cross the obstacles and slopes of 60% for a side slope of 30%, to roll in soft soil or deep mud and in water through its floatability (speed 10 km / h). It could carry a payload of 900 kg and its low center of gravity contributed to its stability.

Testing at Fort Lee and Camp Wallace, Virginia, lasted from May 19, 1965 to May 13, 1966 for 41 days only of real test because of troubleshoots. The PATA behaved well as written above in the very muddy grounds but its manoeuvrability in other fields was limited. Many failures occurred in the track system with tearing bags and overheating of caterpillars bothered the occupants of the cab. The lateral stability at high speed was poor both sides of the bags were flexible.
We suspect that punctures occurred commonly but the companies involved reported that the PATA drive could roll with 5 deflated cells.

The search lasted until 1969 with tire manufacturers with no other prototype.

4 - In Russia

4.1 - Vehicles of NAMI

Pioneers in the research on caterpillars in general and pneumatic tracks in particular, the Russians continued their research at the Institute NAMI, Official Institute Motor Vehicles in Russia, in collaboration with the Bauman Institute in Moscow (formerly Technical University of Moscow) and in 1961 created a prototype called NAMI S-3 from a car series 4x4 Moskvitch transformed into a semi-tracked.

The tests showed a silent operation for up to 40 km / h. Beyond, the elastic nature of the track caused vertical and lateral oscillations. Subsequently in 1965, NAMI gave the name S-3M (photo 13) to its new improved prototype, semi-tracked with three rollers and a rocker, the tracks themselves were made of tire tubes reinforced of bars of steel.

Then, again in 1965, NAMI built the NAMI-0106 (photos 14-15), articulated amphibious tracked vehicle with four pneumatic tubes. Its engine was an M-21 Volga, attached to a 4 speed box UAZ-452 and a main transmission of GAS-69, direction was hydraulic with a turning radius of 5,5 m outside. He climbed slopes of 25 °. The traction strength being lower than a conventional track, one tried a new track 'Honeycomb' containing empty enclosed spaces and mounted on a semi-tracked who became the UAZ-469 (photo 16). Traction progressed but the high price and lack of reliability did not justify the latter type of tracks.

The semi-tracked NAMI S-4 (photo 17 and 18) with a new side strips tread and longitudinal tubes appeared. The whole fairly rigid improved handling.

4.2 - In Belarus

Returning to the mid-60s when a working group of the Bielorussian Institute of Mechanization headed by V. Roudelson in collaboration with the tractor factory in Kharkov (KhTZ) and Krasnyi Rezinchtchick plant realized the experimental tractor 'Evrika' (photo 19) equipped with pneumatic tracks and based on the vineyard tractor V-101. Its maximum speed was 25 km / h. The weight decreased by 15% but the grip also, what made it refuse to agricultural employment. It seemed then to be reserved for geologists and researches was abandoned.

4.3 - At the University of Nizhny Novgorod

In 1970, the Gorky Polytechnic Institute was based at the University of Gorky became again in 1991 University of Nizhny Novgorod. Renamed in 1978 ONIL VM (Research Laboratory, Division of All Terrain Vehicles), the Institute engaged in research on flexible air tracks. It realized a variety of vehicles such as the GAS-47PG, 71PG-GAS in the period 1976-78, the T-54sPG (photo 20) for Kishinev tractor factory and the T-150PG (photo 21) for the Kharkov tractor factory, Ukraine. The Kirovets tractors DT-75, St Petersburg (photo 22) was studied for wetlands.

In 1980, it was concluded that the introduction of tire tracks allowed compaction of the soil much lower very favorable to agricultural machinery. In this area became famous names like Bocharov, Semenov, Veselov, Novikov.

In 1985 were developed excavators E-5015 and E-4121 (photo 23) with air tracks for the emergency repair of pipelines in the region of the Upper Volga.
The same year came the amphibious vehicle STPr6901-01 (photo 24) 10 t payload on pneumatic tracks and components of KAMAZ trucks. One of the models received in 1987 an excavator. The STPr6901 was mass produced but the bars were they not in full rubber ?

In forestry, the prototype of tractor LKhT-100 of the Onega Tractor plant led to a series of 200 caterpillars tires environmentally compatible with the forest soil to Belotserkovskiy RTI plant.

A private JST 'Transport TTM' currently distribute on the market the new products tested in the University of Nizhny Novgorod and in 1997 a major exhibition of new produced vehicles was held in this city with the participation of the greatest authorities of the time.

4.4 - The VACT of Asovtsev made around 2000, following the principle of a band equipped with air bags as PATA.

Russian Researchers dreamed of universal amphibious carrier used for exploration in the inhospitable regions like the 'Far East' as well as Siberian regions of Australia, Asia, Africa or the extreme North and extreme South America. It should be used to explore the coast, coastal fisheries, the algae harvesting, or mariculture, the maintenance of drilling platforms, industries, forests or unloading of vessels remained at large.

Environmental concerns the land keeping in addition to problems in rough seas of the vehicle, Azovtsev developed a prototype of amphibious transport vehicle with a capacity of 0.5 tonnes for a total mass of 1.25 t, the 0.5-VACT (photo 25) whose uniqueness lies in its air bag tracked with a great ride and combined with a good flotation. The hydraulic tests at the University of Moscow confirmed that the vehicle corresponded well to the initial project, and, not passing quickly, they could create a vehicle on that principle to carry useful 60 t. It does not appear to have been followed.

We can finally report a theoric study of tire caterpillar in agriculture by Ch. Zhdanovich of the Belarus State Polytechnic Academia published in a booklet SAE (Society of Automotive Engineers, Pennsylvania) in 1998 at the Off-Road International Transport Congress at Milwaukee, Wisconsin.
Evidence that researches remain active !

5 - Kristi

The amphibious vehicle Kristi KT-4 (photos 26 and 27) known as Kristi 'Water Walker' in 1962 was surrounded by pneumatic bags (supplied by the Army) set on its tracks that allowed the hull to stay out of water. This original vehicle could remain horizontal on the slopes. Few details remain despite its evaluation during the exercise RAVE (Remote Area Vehicle Evaluation) by the U.S. Army.

6 - In Japan

Similar studies in Japan during World War II had led to 'Vehicles to cross the marshes' (photo 28) but we don't know if the bags were inflatable.

8 - W. R. Bertelsen

Dr. William R. Bertelsen, Rock Island, Illinois, built many air cushioned vehicles prototypes designated 'Aeromobile' in the 1950 to 1980. He was also involved in research on vertical flight, particularly by the diverted air flow from a propeller. He also built many crawler prototypes devices with integrated air cushion for all-terrain vehicle (photo 29) which they noticed a presentation at the International Conference on Technology of Air Cushion in Toronto, Ontario in 1987.

This patent from 1985 (photo 30) signed W. R. Bertelsen uses multiple pressurized bags around a caterpillar.

9 - Airoll

Already covered in another chapter, Airoll (photo 31) seemed more like a series than the PATA.
Similarly, the small ATV (All Terrain Vehicle) Canadair Fisher (photos 32 and 33) in 1963-64 may well have also be manufactured in series after a few improvements. The recreational ATV, whose many manufacturers were making a variety of models, were selling very well in the 60s and 70s.

Tracks with pneumatic roller (Photo 34) were well represented in the patents.

10 - Cycling tracked of the Book of Inventions (photo 35)

11 - Toroïdal locomotion

In 1963 was born the first invention in this area but it's from 1972 to 2001 in Russia that the Russian company 'Graderika, Ltd.' in Moscow contributed to research on toroïdal locomotion with Dr. Valeriy Shikhirin. He continued his research in 2002 in a private enterprise : Elastoneering, Inc., Wheeling, Illinois including the following site :

http://www.elastoneering.com/index.htm  

Inverted torus shaped bags  have several applications including propulsion of vehicles (photos 36-37-38). As shown in the photos, the goal is to turn on itself envelope of the inverted toroïdal bag, causing the displacement of the vehicle.
The materials of the torus must be waterproof, strong and elastic and also fine and light. The torus are easily transportable and storable, lightweight, quiet, have a ground pressure very low (less than 0.1 kgf/cm2), a good cushioning coupled with a large carrying capacity. The design of the suspension is very simple and they are many times less energy efficient than a wheel or a real caterpillar. Obviously, they adapt to any terrain. But nothing is said about their durability.

On the website of Youtube:

http://www.youtube.com/user/elastoneering#p/a/f/0/bTXDQL1FMxc
 
They can see, a little before the middle of the video, a scale model of vehicle with inverted torus.

Research on inverted torus seems to be continued since 2008 by Roman Maksymenko of Max-Master, region of Mocow : http://max-master.com/   

The WSL, 'Whole Skin Locomotion' is cited here for reference to its similarity to the toroïdal locomotion but the prototype is not equipped with tire tracks.
This system is analogous to the propulsion of amoebae which only the outer orbits the center and progresses. This new propulsion system for small robots terrain is tested by Dr. Denis Hong in Romela, 'Robotics and Mechanics Laboratory' at the Polytechnic University of Virginia, Blacksburg, Virginia.