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50-463: Unic is a former French car manufacturer. Unic , UNIC , or UNICS may also refer to: Unic Unic was founded by Georges Richard after he left Richard-Brasier . In 1905 Richard had a meeting with the entrepreneur-financier Baron Henri de Rothschild and obtained funding for the creation of the " société anonyme des automobiles Unic ", based at Puteaux . The objective was to manufacture "unique" (rather than mainstream) vehicles, and at

100-494: A 2 + 1 ⁄ 2 -litre straight-8 power unit and sat on a substantial 3,460 mm (136.2 in) wheelbase. It was priced at 55,000 francs in bare chassis form. The 8-cylinder Unic "Type H1" introduced in 1928 was progressively updated in accordance with the changing tastes of the time: by 1933 car had evolved into the Unic "Type H3" and the engine size had grown from 2 + 1 ⁄ 2 litres to 2646 cc. October 1933

150-566: A 2867 cc (15/16CV) version of the aggressively priced and marketed Citroën Traction. Few customers in this class were willing to pay the price for the Unic's virtues of dependability, style and space, and Unic passenger car production ceased in July 1938. After 1938 Unic concentrated in the truck business, being one of the leading French makes. In 1966 it was taken over by the Italian company Fiat and eventually merged into Iveco in 1975. In 1952,

200-472: A 3,160 mm (124.4 in) wheelbase. The imposing six-cylinder Unic Type U6C provided 85 hp (63 kW) from a 3,000 cc engine (17CV), transmitted via an electromagnetic "Cotal" preselector gear box, with a choice of wheelbase lengths between 3,200 mm (126.0 in) and 3,370 mm (132.7 in). The appeal of Unic passenger cars by this time derived not from technical brilliance nor from stunning originality. Those who appreciated

250-479: A Newton centrifugal clutch . This was a multiple plate dry clutch , similar to racing manual clutches of the time, but with the pressure plate centrifugally actuated to engage at around 600rpm. Pure racing cars, such as the ERA , avoided a clutch altogether and relied on the progressive engagement of the gearbox's band brake on lowest gear when starting. When fitted with a centrifugal clutch or fluid coupling, starting from

300-404: A driver-controlled clutch entirely. Some use one solely for starting from a standstill. Preselector gearboxes were most common prior to the widespread adoption of the automatic transmission, so they were considered in comparison to the " crash gearbox " type of manual transmission. Preselector gearboxes were often marketed as "self-changing" gearboxes, however this is an inaccurate description as

350-400: A form of pre-selective gearbox that was built by Maybach and offered 8 ratios. The shift mechanism was hydraulic, to reduce driver effort. Clutches were used in combinations, allowing many more ratios than actuators. There were three hydraulic cylinders, each with two positions and controlling dog clutches for gear trains arranged on four shafts. The cylinders were controlled by a rotary valve on

400-491: A simple quadrant gear lever and activated by pushing the lever sideways into its gate. The combination of the three cylinders permitted eight different ratios, although in reverse these were limited to just the lowest four. When a captured Tiger I tank was studied by the British in 1943, the report on the gearbox was carried out by Armstrong Siddeley motors. A multi-clutch gearbox avoids the difficulties of shifting gear by avoiding

450-697: A small input force. Walter Wilson was a major co-inventor of the armoured tank during and after World War I , and was responsible for the 1918 British Mark V tank using an epicyclic steering gearbox. The Lanchester Motor Company in the United Kingdom also produced cars with manually-controlled epicyclic gearboxes from 1900 and built an experimental tank (the Lanchester Gearbox Machine or Experimental Machine K ) fitted with an epicyclic gearbox. Walter Wilson continued experimentation with epicyclic gearboxes for cars and in 1928 his "Wilson gearbox"

500-407: A standstill involved simply selecting first gear, then the clutch would automatically engage once the accelerator pedal was pressed. On other cars, the gear change pedal functioned like a clutch when starting from a standstill. The Wilson gearbox relied on a number of epicyclic gears, coupled in an ingenious manner that was also Wilson's invention. Successive gears operated by compounding or 'reducing

550-454: Is moved, without requiring the separate gear change pedal. Compared with the contemporary (non- synchromesh ) manual transmissions, preselector gearboxes were easier for drivers to operate smoothly, since they did not require techniques such as double de-clutching . Preselector gearboxes also had faster shift times, could handle greater power outputs and had less mass and could shift under load. A design advantage of many preselector gearboxes

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600-464: Is that the friction components are brakes , rather than clutches . This meant that non-rotating brake bands could be used for the parts which are subject to wear, which results in a simpler design than a rotating component such as a typical clutch. The wearing components could also be mounted on the outside of the mechanism (rather than buried within it), providing easier access for maintenance and adjustment. The most common type of pre-selector gearbox

650-432: Is that the gear shift lever allowed the driver to "pre-select" the next gear, usually with the transmission remaining in the current gear until the driver pressed the "gear change pedal" at the desired time. The design removed the need for the driver to master the timing of using a clutch pedal and shift lever in order to achieve a smooth shift in a non-synchromesh manual transmission. Most pre-selector transmissions avoid

700-464: The 22nd Paris Motor Show , only one of the two cars on show was fitted with a 4-cylinder engine. This was an evolution of the two-litre model exhibited in 1924, now branded as the Unic "Type L9", with a 3,150 mm (124.0 in) wheelbase and usually fitted with "Torpedo" or "Berline" (saloon/sedan) bodies. However, for the 1929 model year attention was now focused on the company's first 8-cylinder model. The new Unic 14 CV/HP "Type H1" featured

750-496: The 1935 ERA R4D , and hillclimbing cars such as the 1930s Auto Union 'Silver Arrows' . Several buses built in the United Kingdom from around 1940 to 1960 had preselector transmission, including those built by Leyland, Daimler and AEC. The AEC RT type , a bus commonly used in London during this period, used compressed air to actuate the gear shifts, while other gearboxes used mechanical actuation. Typical operation of London buses

800-731: The March 1917 Oldbury gearbox trials testing different transmissions on eight British Heavy Tanks . Each ratio has its own shaft, and its own clutch. Provided the clutches are interlocked so that only one may be engaged at a time, the system is simple. In the early 1980s this transmission was developed for urban buses in the UK as the Maxwell , with a four-speed gearbox. UK buses are mostly double-deckers with rear-mounted transverse engines. Their use also involves much stop-start driving, thus heavy clutch wear for conventional gearboxes. The advantage of this arrangement

850-509: The Wilson design was the use of self-adjusting nuts on each band, to compensate for wear. The action of engaging and disengaging each band was sufficient to advance the ratchet nuts and so adjust for wear by taking up any slack. During the 1920s and 1930s, several French luxury car manufacturers used three-speed or four-speed preselector gearbox manufactured by Cotal. A unique aspect of the Cotal gearbox

900-444: The Wilson patents. The Roesch gearbox was vastly revised in both design and materials, resulting in a lighter gearbox that was able to withstand three times the power of the Wilson gearbox. This gearbox would automatically pre-select first gear when reverse was engaged. On engaging second gear, the gearbox would then pre-select third, and fourth when third was engaged. It would then cycle between third and fourth until another gear

950-468: The arrival and production of hydraulic automatic transmissions , starting from the mid-1930s, to the early-to-mid-1990s. These systems would either fully eliminate the clutch pedal, or would retain the clutch pedal, but the clutch would only be required to be operated for performing standing starts from a stationary position, not for shifting gears. Further advancements and development were introduced later, and several other methods have been used to automate

1000-412: The brake band, thus the need for the foot pedal. The actual movement of the brake bands was controlled by the 'toggle' mechanism, a distinctive feature of the Wilson design. When the pedal was pressed and released, a series or 'busbar' of finger-like levers were pressed upwards by a strong coil spring, against a series of light linkages or 'operating struts'. The position of each linkage was controlled by

1050-449: The business. During the 1920s, a 1997 cc sports model was marketed and in some models sleeve valve engines were used. By the time of the 19th Paris Motor Show , in October 1924, Unic were exhibiting three passenger cars. All had four cylinder engines, although large 4-cylinder engines such as that fitted in the 16HP model were by now seen as rather old fashioned: Four years later, at

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1100-460: The cars were impressed by excellent reliability resulting from a meticulous approach taken during the production process. Also admired were their elegant spacious bodies, most of which came from the coach builder Letourneur et Marchand or from their subsidiary, Autobineau. Unic cars by now were not being sold in large numbers and this was reflected in the price. At the 1937 Motor Show the standard steel-bodied Unic Type U-4 D with its 12CV engine

1150-486: The change gear pedal. During the 1930s, Humber cars were fitted with a four-speed preselector gearbox produced by Laycock-de Normanville . It was broadly similar to the Wilson, but used direct hydraulic actuation of the brake bands (selected via a lever on the steering column) therefore avoiding the need for a change-gear pedal. Several Talbot cars in the 1930s— such as the 1932–1935 Talbot AX65 Darracq — used an "accelerating gearbox" designed by Georges Roesch, based on

1200-410: The company's headquarters moved from Villejuif to Boissy St Léger , where a second facility was established in 1995. Preselector gearbox#Cotal A preselector gearbox is a type of manual transmission mostly used on passenger cars and racing cars in the 1930s, in buses from 1940–1960 and in armoured vehicles from the 1930s to the 1970s. The defining characteristic of a preselector gearbox

1250-422: The correct ratio before engaging the clutch, giving a far slower shift. Semi-automatic transmissions, usually in the form of clutchless manual transmissions , only automate the clutch system, and have used various different control systems to facilitate clutch operation, while still requiring the driver's input to manually change gear. These systems were introduced by numerous production car manufacturers, prior to

1300-409: The driver is required to choose the gear (and often manually actuate the gear change). An automatic transmission is a true "self-changing gearbox" since it is able to change gears without any driver involvement. There are several radically different mechanical designs of preselector gearbox. The best known is the Wilson design. Some gearboxes, such as the Cotal, shift gears immediately as the control

1350-709: The firm was taken over by Simca , headed by Henri Pigozzi , who wanted a commercial vehicle production unit. Trucks of this period are commonly referred to as Unic-Simca trucks . In 1956 the French arm of the Swiss truck manufacturer Saurer was taken over. In 1966 Unic joined the Fiat Group . In 1975 a holding company named IVECO was established covering truck and bus brands such as Fiat, OM , Lancia , UNIC and Magirus . In 1976 UNIC-FIAT S.A. became UNIC S.A. In 1992 IVECO UNIC S.A. changed its name to IVECO FRANCE S.A. In 2003,

1400-549: The gear change pedal. The preselector buses were also exported to various countries – the AEC Regent III with the Wilson type gearboxes were used in Western Australia for 25 years as part of the public transport fleet from 1950 until 1976. Some 1950s-era James motorcycles were built using Villiers engines and a preselector gearbox. These were operated by pressing the gear pedal down to select 1st gear, then pulling in

1450-437: The gear selection camshaft. If the cam (for each gear) held the linkage in place, rather than allowing it to swing out of the way, the busbar finger would then press, via the operating strut, onto the toggles controlling the brake bands themselves. These toggles provided the additional leverage necessary to hold the brake band in place, under the force of the coil spring, until the pedal was next pressed. A further characteristic of

1500-443: The gearwheels in a preselector box are permanently in mesh in an epicyclic layout. Changing gear with the Wilson box relied on the control of the brake bands that held each epicyclic's annulus in fixed position. The brake band to be selected was controlled by a rotating cam, moved by the gear shift lever. Only one band was engaged for each gear selection. This small hand-operated lever could not provide enough power to engage and lock

1550-426: The last time, and for the 1937 October Motor Show the six-cylinder model was also given a more streamlined look, in line with the fashion of the time. By this time the passenger car range was down to just these two models. The Unic Type U4D was a four-cylinder 2,150 (12CV) car which featured overhead valves and offered a maximum output of 55 hp (41 kW), supported by a robust, rather traditional chassis with

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1600-416: The need to shift at all. It operates as a number of separate gearboxes, each one controlled by a separate clutch, interlocked to avoid multiple selection. Selecting a gear is a matter of selecting the appropriate clutch. An advantage of this type is that it's simple to arrange remote operation, as there is no gear shift linkage as such, merely duplication of a clutch linkage. This type of gearbox appeared in

1650-458: The next gear using a lever mounted to the steering wheel, then pressed the 'gear change pedal' (often located in place of the usual clutch pedal) to activate the gearchange at the desired time. The Wilson gearbox was produced with a variety of clutches. The best-known is the fluid flywheel , used for touring cars such as the Daimler (Armstrong Siddeley used a centrifugal clutch). Sports cars used

1700-438: The overall set, and the two clutches select which gearbox is in effect. Changes within the gearbox are done automatically, to predict which ratio the driver will require next. Provided that the next ratio has been selected correctly (i.e. the computer guessed correctly as to an up-shift vs. a down-shift) the shift itself is merely a rapid movement of the clutch. Unexpected shifts may confuse the system though and it must first select

1750-553: The process of clutch operation and gear selection together simultaneously, most notably with the modern automated manual transmission , introduced by several car manufacturers in the 1990s, but first pioneered by Isuzu , with their NAVi5 transmission , in 1985. Preselector gearboxes were used in several racing cars and motorbike, including the International Six Days Trial 1921 and 1922 – Switzerland were Marcel Viratelle motorcycles were entered with series motorcycles;

1800-471: The production of delivery vans and other small utility style vehicles. The 1943 cc 12 CV (9 kW) four-cylinder model (used mainly as a taxi ) was extremely successful and survived in production for nearly 20 years. (The engine was enlarged later to 2120 cc.) During World War I , taxis made by the company participated in the Marne operation. After World War I, a new four-cylinder (1847 cc)

1850-411: The ratios could be more closely spaced . Although this same arrangement of epicyclics would become the precursor for the post-war automatic transmission, the automatic transmission's use of a torque converter, together with the broad power band and excess power of US V8 engines, meant that wider-spaced, thus fewer, ratios were acceptable. Unlike the "crash" gearboxes of the first half of the 20th century,

1900-408: The reduction' provided by the previous gear. A separate epicyclic was required for each intermediate gear, with a cone clutch for the straight-through top gear and a further epicyclic for reverse. Four gears were provided, at a time when many cars (especially American ones) usually only had a three speed gearbox. This was owing to the sporting, or indeed racing, market for the Wilson gearbox, so that

1950-455: The start the company made only light cars and taxis with two-cylinder and four-cylinder engines. The taxi business would remain important to Unic for more than three decades, while Rothschild's steady financial support through good times and bad, provided stability which sustained the business, critically during the immediate post- war years. Although the manufacturer's initial range was restricted to light cars, their popularity as taxis led to

2000-492: Was invented. Walter and one of the co-owners of Armstrong Siddeley Motors formed the Self-Changing Gears Ltd. company (initially called Improved Gears Ltd. ) to design and build the Wilson gearbox. The 1929 Armstrong Siddeley Thirty was one of the first cars to use the Wilson gearbox. The gearbox was also built under licence by other manufacturers including Cord, ERA, Daimler and Maybach. The driver pre-selected

2050-461: Was its use of four clutches, all easily serviced from outside the engine assembly, without needing to remove the engine. The clutches were multi-plate oil-supplied wet clutches. The first gearboxes gained a reputation for unreliability and in 1985 the original developers, Brockhouse, licensed them to Avon Maxwell Transmissions. A developed version, with an enlarged oil pump, was available as a retrofit for most UK buses. An unusual feature of this gearbox

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2100-434: Was nevertheless the last time an 8-cylinder passenger car would appear on the Unic show stand. For the next few years the company focused on 4-cylinder cars in the 11 CV/HP tax band, just as they had through the mid-1920s. For 1934 Unic announced their new "Type U4" model, featuring a 2-litre side-valve engine and now also employing a 4-speed transmission. The body-work of the standard 5-seater "berline" (sedan/saloon)

2150-514: Was no longer completely flat-backed, but the proportions of the car may have drawn criticism, since between the car's October 1933 launch and May 1934, the rear overhang was slightly increased, while at the front a slightly raked grill replaced the flat one, and the overall profile became a little more streamlined. In addition to this passenger car, Unic continued to produce through 1934 a similarly sized taxi of "great robustness". In March 1937 Unic updated their four-cylinder passenger car model for

2200-489: Was offered, along with the taxis. In 1922 the firm introduced a three-ton truck, called the Unic MSC, which marked the start of a switch towards production of larger commercial vehicles. 1922 was also the year when the founder of Unic, Georges Richard, died while awaiting transfer to a Paris clinic, following a motor accident en route to Rouen . Georges Dubois, hitherto in charge of vehicle testing, took on responsibility for

2250-558: Was pre-selected manually. Initial versions were produced without any form of clutch, however a centrifugal clutch was soon added to the design. Described by Talbot as the 'Traffic Clutch'. this was a simple device, with two radially swinging shoes (similar to a drum brake). An early pre-selector gearbox was a prototype three-speed motorcycle gearbox patented by fr:Marcel Viratelle in France in 1906. The design and production were very compact. The 1942–1945 German Tiger I armoured tank used

2300-515: Was priced at 53,750 francs (or 35,500 francs in bare chassis form). The slightly more powerful 13CV Talbot Type T4 "Minor" was listed at 42,500 Francs (or 35,000 Francs in bare chassis form), while from the top end of the Citroën range a long wheel base "familiale" version of the Traction 11CV Longue could be had for 28,900 francs including the body, while prototype testing was already well under way of

2350-410: Was the Wilson, which used an epicyclic design . A precursor to the Wilson gearbox was the manually-controlled epicyclic gearbox used in the 1901–1904 Wilson-Pilcher cars built in the United Kingdom. One of the company directors, Walter Gordon Wilson , had become an advocate for the benefits of the epicyclic gearbox, which allowed large torques to be transmitted whilst still being controllable through

2400-428: Was the ability to engage first and second gear simultaneously. This acted as a 50 hp hydraulic retarder . The idea of rapid shifting by clutch alone has also been developed as the dual-clutch transmission, in recent high-performance cars. This combines the simplicity of a shifting gearbox with the rapid shifts of a clutch-based design. There are effectively two separate gearboxes, each offering alternate ratios from

2450-440: Was the use of electromagnetic clutches (instead of band brakes) to engage the gears. A downside to this approach was that a loss of electrical power meant that the engine could no longer drive the wheels. The clutches were controlled by a simple dashboard or column-mounted switch, described as "a cherry on a cocktail stick", and relays. There was no mechanical servo action, so no need for the Wilson's cam or toggle arrangements and

2500-405: Was they had a very low first gear, only used on hills, so the driver when starting would select second gear, depress and release the change gear pedal to engage the transmission, and then select third ready for changing gear on the move, all this done while the bus was still stationary. On starting, just the accelerator pedal was pressed, with the eventual shift into third gear made by simply pressing

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