Milestones in technical development
Weighing and feeding
The illuminated dial weighing and printing machine with 3000 pressure stages, improved in 1950, gave the company an important edge over competing scales manufacturers.
In 1952 the first legal-for-trade hump scales (still mechanical) were delivered to weigh moving wagons. Hump scales were first installed in a line with steep gradient in 1962, making the weighing process even faster.
The production of the successful illuminated dial weighing and printing machines was handed over to subsidiary Florenz in Braunau, enabling the company to concentrate on electromechanical weighing systems, which offered the same accuracy but with much more flexible registration options. Another milestone followed with the first speed-controlled weighfeeder, which was later fitted with a load cell. The first blending system also began to be developed using this new technology. The first electromechanical crane scales were delivered in 1955, heralding the start of the transition from mechanical to electromechanical scales, in which Schenck was a key player. In 1961 the company designed its own ring torsion load cell.
This was soon followed by the introduction of digital technology, the use of the first computers, and special scales on the cutting edge of testing technology: a load machine (standard force measuring device) to determine the accuracy of load cells and a wind tunnel scale.
During the 1950s, the chains in transport systems were mostly replaced with belts.
In vertical transport, in 1955 the pocket belt conveyor replaced the pendulum bucket elevators which had been manufactured for over half a century. Other successful developments in the years that followed included a ladle belt conveyor for hot material, cement clinker and lead and iron sinter, a scraper for long and round bunkers, and a scoop belt conveyor.
Schenck also entered a completely new line of business: machines and systems for particle board production. The company began by supplying conveyors and weighing solutions for discontinuous operation, and in 1953 began to develop and market spreaders for continuous particle spreading, flashers with discharge devices for wet and dry chips, and special conveyors for profiled sheet metal.
Numerous cargo handling systems were supplied to the automotive industry and other sectors. In 1968 the company entered another field with the first sorting and conveying system for air freight.
Vibration conveying and screening
In 1945 the demand for vibration conveyors from the pre-war markets was so low that the factory temporarily designed and manufactured roof tile production machinery in order to stay open. These included screening machines for handling debris.
In 1947 a new department was created for the design of vibratory equipment, which used to be part of the transport systems department. It built on successful developments of earlier years and soon afterwards delivered the first freely vibrating machines driven by two synchronised unbalance motors, including the first screens for hot sinter and a spiral vibrating conveyor for vertical transport.
Transport capacities continued to increase and dimensions grew accordingly, with screening machines reaching a width of 4 m by 1967. At the same time a process was developed to transport dusty bulk materials on vibrating conveyors, which went into successful use.
Finally, the increased use of vibratory equipment in process engineering created another new area with constantly changing demands. One of the most recent deliveries was a set of 18 m2 vibratory systems to handle cast parts weighing up to 60 tonnes.
The company had started designing a balancing machine in 1915, and after constant improvements to the first model, sales increased continuously and rose dramatically in the post-war years, particularly in the export market. As generators and turbine rotors increased in size, a large number of machines was built for balancing bodies weighing up to 30 tonnes.
In 1927 the Transvaal Power Corporation bought the first machine for balancing bodies weighing 3 to 45 tonnes for its Rosherville Power Plant. This was soon followed by an order from Ateliers de Constructions Mecaniques (A.C.M.) in Jeumont for a machine that could handle components of 60 to 100 tonnes, 7 metres long, with a journal diameter of up to 600 mm and a speed of up to 3900 revolutions per minute.
In 1924 the first dynamic material testing machine was built to measure fatigue strength. In addition to a number of drawing/pressing test machines with direct imbalance drive and a load change rate of 3000 cycles per minute, the flexural stress machine with rotating test bar was especially successful. So too were the plate bending and torsion machine and in smaller quantities the high-frequency drawing/pressing machine for small specimens, developed under licence from Signal-Gesellschaft mbH in Kiel, with a load change rate of 30 000/min. Later the company also designed a testing machine for the dynamic series testing of valve springs.
1925 saw the development of a new balancing machine known as the X machine for small and medium rotors, which was based on a patent issued in 1916 and allowed the balancing levels of the balancing body to be moved mechanically.
In 1922/23 the company made the first attempt to use vibration for material transport. Once the initial difficulties had been overcome, the result was reliable conveying equipment for hot and abrasive materials such as iron sinter.
A few years later screen panels were added to these vibrating conveyors, allowing them to sort bulk materials by particle size.
The transport systems department developed conveying systems for assembly line production, primarily for the automotive and foundry industries. These included coverhead conveyors, floor conveyors, roller conveyors and slat conveyors.
The factory built a semi-automatic crane scale, a special scale for locomotive coaling and a rail vehicle scale with cable relief, which caused no track discontinuation and also minimised the vertical and angular travel of the arms that lowered the weighbridge, reducing wear on the edges. Almost 600 of these scales were delivered.
In 1928 the newly established power brakes and brake test rig department designed and shipped the first test rig for measuring the performance and uphill capability of cars and lorries, equipped with four drums, for former automotive manufacturer Adler. This was followed in 1929 by the water-cooled band brake designed by Prof. Kluge in Karlsruhe.
In 1930 the first weighfeeders were built, as well as batch scales for concrete mixing plants and roadmaking material, rail car body weighing equipment for express trains, and the first illuminated dial balances. In 1931 the illuminated dial balance was equipped with a numerical printer which, after a few design improvements, would finally be approved for calibration in 1938. The first rail and road vehicle scales to be produced without the standard load relief facility were introduced in 1933.
In 1933/34 the company was able to recruit new shop-floor and office staff again and in July 1934, weekly working hours were once again increased to 48 hours. The workforce increased to 600 in 1936, to 700 in 1938, to 795 in 1939, and to 1060 by 1944. Capacity utilisation increased accordingly, as did sales.
In 1940 the share capital was raised to 1 400 000 Reichsmarks and in 1942 it was increased again to 1 750 000 Reichsmarks.
The testing machine department continued to develop new drawing, pressing and torsion machines and "Pulser" resonance machines, which made Schenck one of the biggest manufacturers of vibration testing equipment, until 1937.
In 1939 the 23-year-old "mechanical" frame of the balancing machines was replaced by an "electrical" frame. In 1942 the company introduced an electrical fine balancing machine with oscillograph display.
In 1943 Schenck delivered what was then the world's biggest double-drive fatigue testing machine (3700 kN) to the Deutsche Versuchsanstalt für Luftfahrt (DVL), the aviation laboratory at Adlershof in Berlin. Equipped with program control, it measured the fatigue strength of large aircraft parts.
In 1935 the power brakes and vehicle test rig department developed the first slide-controlled Schenck hydraulic brake. Both power brakes and test rigs became a busy area of activity in the years that followed. For example, Schenck delivered test rigs for aircraft wheel brakes and a six-drum test rig for the brakes on three-axle vehicles. In 1940 the company shipped a drop hammer for aircraft shock struts and in 1941 a test rig for aircraft tyres and brakes with a contact pressure of 30 tonnes on a drum 2.5 m in diameter and a drop hammer for 100 tonnes of impact force. In 1937 a steam brake was developed for Motoren-Werke Mannheim, with twenty units being supplied to the factory by 1944.
The first circulating brake was designed in 1944. The weighing machines business was enjoying rising sales thanks to the illuminated dial balance printer. The first tube scale equipped with this printer and a slide rule to measure the weight per metre was delivered in 1939. In addition to growing sales of previously developed models, special mention should be given to the torque measuring systems (an illuminated dial balance with extra-heavy pendulum) for measuring the torque of aircraft engines, which were manufactured in large numbers.