> News & Media  >Back Number 2008-2009 Issued on January 5, 2009 (No.76)
90 years in tandem with our clients
1918 - 2008

** SAKAI’s growth 3 **
A history of light weight compaction equipment
 Light weight compaction equipment of 1 ton class or even smaller were used in Europe soon after the war and imported to Japan to meet growing demand.
 Under these circumstances, Sakai Heavy Industries entered into a technical agreement with Rosen Hausen Machine Bau Co. Ltd of the former Western Germany in 1969 and developed the VVW3400 model (900kg class) hand guide roller (a twin-wheeled vibratory roller) shown in Photo 1.
(Photo 1)
 This machine was the first light weight compaction equipment developed by Sakai Heavy Industries.
 This was followed by a number of prototypes to produce a series of machines, but at the time of the first oil shock in 1973 the demand for light weight equipment did not diminish to the extent of non-vibratory heavy equipment, therefore focusing on sales of light weight equipment, Sakai Heavy Industries developed independently the SV10 (1000kg) and SV6 (600kg) hand-guide rollers shown in Photo 2.
 Model SV6 had a single shaft eccentric oscillator, mounted in the middle of the chassis (vibratory chassis), and in the SV10, in addition to the vibratory function, the forward-reverse function was changed from a mechanical to a hydraulic motor, enabling smoother operation.
 In 1994 Sakai Heavy Industries developed the fully hydraulic powered HV Series with a ground-breaking hydraulic motor installed in the roller.
 This removed the need for chain driven parts in the rollers and it became possible to reduce the clearance on both sides to a minimum.  Further, in 2000, Sakai developed the HS Series with improved steering for better operation.
(Photo 2)
Leading Fully Hydraulic Power Systems
 Sakai Heavy Industries developed their first plate compactor the PC7 (70kg) powered by a 4-stoke engine in 1978(Photo 3), this was followed by the development of the PC80 (80kg), PC6 (60kg) and PC4 (40kg) models, increasing the range of plate compactors.
(Photo 3)
 In response to demands of the times Sakai Heavy Industries developed quieter plates with sprinklers, a unique reverse plate and a one-touch-release belt cover.  Further, the PF500 (80kg) forward-reverse plate was developed in 1988 adding to the range of plates and responding to the requirements of export markets.
 Sakai rammers came into service in 1982 with the development of the VT6 (60kg) model (Photo 4).
 This equipment did not have the belt drives and direct grease lubricated engines which were standard in the leading ranges at the time, but the direct transmission engine with oil bath, which are standard in modern leading models. The first rammers developed had only 2-stroke engines, which were replaced with the easily maintained and more environmentally friendly 4-stroke engine, increasing the range of the “high-jump” and other specifications.
(Photo 4)
 These were followed by the easier handled, low centre of gravity RV Series, and the RS Series designed for a more stable thrust and reduced vibration to the operator, features still seen in modern rammers.
A history of road cutters and stabilisers.
 Continuing the history of light weight compaction equipment, here we introduce the history of the development of road cutters (#1) and road stabilisers (#2) used in road maintenance.

 The Japan archipelago redevelopment plan under the Tanaka Cabinet had by 1972 expanded urban renewal, and rail and expressway networks. Traffic volume exploded, vehicles became bigger and heavier causing considerable damaged to paving. Under these circumstances Sakai Heavy Industries developed the ER160 road cutter for road maintenance shown in photo 5. Traditionally, in paving maintenance, after heating, the paving surface was stripped with graders and then underwent various processes of re-paving.

 However, this construction method became expensive, inefficient and incapable to respond to the accelerating demand for road maintenance. Responding to these conditions, the ER160 was designed as a wheeled tractor unit combined with a rotary road surface cutter mounted in the centre of the vehicle. With this design it was possible to achieve faster cutting and to reopen the road to traffic sooner. This became the basic design of the road cutters and subsequent civil engineering machinery.
(Photo 5)
On the other hand, clearing of rubble from road cutting operations became the cause of considerable traffic congestion, because at that time wheel loaders and transport dump trucks were used in combination, making it necessary to control and often close two lanes of traffic.For this reason, in 1982 Sakai Heavy Industries developed and introduced what was to become the fundamental design of road cutters today, the ER300 (Photo 6) combining into one machine, cutting, rubble collection and loading functions. ERF300
(Photo 6)
 Over time Sakai Heavy Industries developed more equipment, including the ERF600 (1987, ER750F (1993) and most recently the ER552F (2006).

 In particular since the ERF600 all equipment utilised the automatic cutter control system (ACCS) making it possible to control the cutter depth, and camber incline. This system rapidly improved the often stated essential requisites of accuracy and operation efficiency.
(Photo 7)
 Further, in 1977, to meet customer needs in Japan, Sakai Heavy Industries developed the highly manoeuvrable wheeled stabiliser the PM170 focusing on a suitable size for narrow urban road and for laying composite to depth of 400mm (Photo 7). The location of the rotor (the agitate composite mixer) mounted in the centre and the lateral (left-right) shift unit became the fundamental design of all subsequent machinery developed since.
 Improving performance and at the same time meeting market needs the current primary road stabilisers, which are the PM450 (developed 1989) and PM500 (1994), have over many years been operated in diverse situations.
 The Sakai Heavy Industries’ light weight compaction equipment, the road cutter and the road stabiliser introduced here, are a historical part of the Sakai product range employed by our customers.

 To the future, Sakai Heavy Industries continue to improve product quality, to supply environmentally friendly, stable, reliable, safe equipment.

#1 Equipment to grind the surface of damaged road surfaces.
#2 Equipment used to add additives to weakened roadbed then agitate, mix and reuse.

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