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78-445: The type equipped a number of RFC and RNAS squadrons both in its original observation role and, equipped with a forward-firing Lewis gun mounted on the top wing, as a fighter. Data from Parmentier General characteristics Performance Armament Lewis gun The Lewis gun (or Lewis automatic machine gun or Lewis automatic rifle ) is a First World War–era light machine gun . Designed privately in

156-465: A Foster mount , which allowed firing directly forward outside the propeller arc. The Foster mount usually incorporated an arc-shaped I-beam rail as its rearmost structural member, that a Lewis gun could be slid backwards and downwards along the rail towards the cockpit, to allow the ammunition drum to be changed in flight – but RFC fighter ace Albert Ball VC also understood that the Lewis gun in such

234-608: A Foster mounting on the top wing to elevate a Lewis gun above the propeller arc for unsynchronized firing, including production S.E.5/S.E.5a fighters and field-modified examples of the Avro 504 . For the use of observers or rear gunners, the Lewis was mounted on a Scarff ring , which allowed the gun to be rotated and elevated whilst supporting the gun's weight. Until September 1916 Zeppelin airships were very difficult to attack successfully at high altitude, although this also made accurate bombing impossible. Aeroplanes struggled to reach

312-400: A scroll chuck . Non-invertible functions, which require the groove to self-intersect, can be implemented using special follower designs. A variant of the face cam provides motion parallel to the axis of cam rotation. A common example is the traditional sash window lock, where the cam is mounted to the top of the lower sash, and the follower is the hook on the upper sash. In this application,

390-673: A German advance along the Calonne/Robecq road, noting 'we fired the gun in turns until it was too hot to hold' and recording that 400 German casualties were caused, 'chiefly by my Lewis gun!'. The US Army never officially adopted the weapon for infantry use and even went so far as to take Lewis guns away from US Marines arriving in France and replace them with the Chauchat LMG —a practice believed to be related to General Crozier's dislike of Lewis and his gun. The divisions of

468-629: A Vickers gun to manufacture (the cost of a Lewis gun was £165 in 1915 and £175 in 1918; the Vickers cost about £100), Lewis machine guns were in high demand with the British military during the First World War. The Lewis also had the advantage of being about 80% faster to build than the Vickers, and was a lot more portable. Accordingly, the British government placed orders for 3,052 guns between August 1914 and June 1915. Lewis guns outnumbered

546-405: A cam for the lathe mechanism. A face cam produces motion by using a follower riding on the face of a disk. The most common type has the follower ride in a slot so that the captive follower produces radial motion with positive positioning without the need for a spring or other mechanism to keep the follower in contact with the control surface. A face cam of this type generally has only one slot for

624-497: A constant velocity rise followed by a similar return with a dwell in between as depicted in figure 2. The rise is the motion of the follower away from the cam center, dwell is the motion where the follower is at rest, and return is the motion of the follower toward the cam center. A common type is in the valve actuators in internal combustion engines. Here, the cam profile is commonly symmetric and at rotational speeds generally met with, very high acceleration forces develop. Ideally,

702-402: A convex curve between the onset and maximum position of lift reduces acceleration, but this requires impractically large shaft diameters relative to lift. Thus, in practice, the points at which lift begins and ends mean that a tangent to the base circle appears on the profile. This is continuous with a tangent to the tip circle. In designing the cam, the lift and the dwell angle θ are given. If

780-408: A device that converts rotational motion to reciprocating (or sometimes oscillating) motion. A common example is the camshaft of an automobile , which takes the rotary motion of the engine and converts it into the reciprocating motion necessary to operate the intake and exhaust valves of the cylinders . Cams can be characterized by their displacement diagrams, which reflect the changing position

858-399: A field-achieved configuration, however, neither gun-jam clearing, nor drum magazine replacement were possible on their Lewises during a mission. Lewis guns were also carried as defensive guns on British airships. The SS class blimps carried one gun. The larger NS class blimps carried two or three guns in the control car and some were fitted with an additional gun and a gunner's position at

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936-614: A five-wheeled sand-driven clock, artificial paper figurines within a revolving lantern, all utilized cam mechanisms. The Chinese hodometer which utilized a bell and gong mechanism is also a cam, as described in the Song Shi. In the book Nongshu, the vertical wheel of a water-driven wind box is also a cam. Out of these examples, the water-driven pestle and the water driven wind box both have two cam mechanisms inside. Cams that rotated continuously and functioned as integral machine elements were built into Hellenistic water-driven automata from

1014-422: A follower being raised over 24 hours by the cam in a spiral path which terminated at a sharp cut off at which the follower would drop down and activate the day advance. Where timing accuracy is required as in clocking-in clocks these were typically ingeniously arranged to have a roller cam follower to raise the drop weight for most of its journey to near its full height, and only for the last portion of its travel for

1092-427: A follower on each face. In some applications, a single element, such as a gear, a barrel cam or other rotating element with a flat face, may do duty as a face cam in addition to other purposes. Face cams may provide repetitive motion with a groove that forms a closed curve or may provide function generation with a stopped groove. Cams used for function generation may have grooves that require several revolutions to cover

1170-404: A follower would make as the surface of the cam moves in contact with the follower. In the example shown, the cam rotates about an axis. These diagrams relate angular position, usually in degrees, to the radial displacement experienced at that position. Displacement diagrams are traditionally presented as graphs with non-negative values. A simple displacement diagram illustrates the follower motion at

1248-628: A key duplication machine, where the original key acts as a control cam for cutting the new key. Cam mechanisms appeared in China at around 600 BC in the form of a crossbow trigger-mechanism with a cam-shaped swing arm. However, the trigger mechanism did not rotate around its own axis and traditional Chinese technology generally made little use of continuously rotating cams. Nevertheless, later research showed that such cam mechanisms did in fact rotate around its own axis. Likewise, more recent research indicates that cams were used in water-driven trip hammers by

1326-516: A mount also retained its original trigger, and could thus be fired upwards . He used the upward firing Lewis to attack solitary German two-seater aircraft from below and behind, where the observer could not see him or fire back. It was his use of the weapon in this way, in a Nieuport, that led to its later introduction on the S.E.5/S.E.5a: Ball had acted in a consultant capacity on the development of this aeroplane. The later Sopwith Dolphin , already armed with twin synchronized Vickers guns just forward of

1404-399: A plate or block, may be one or more slots or grooves in the face of an element, or may even be a surface profile for a cam with more than one input. The development of a linear cam is similar to, but not identical to, that of a rotating cam. A common example of a linear cam is a key for a pin tumbler lock . The pins act as followers. This behavior is exemplified when the key is duplicated in

1482-595: A quadruple mount was developed for motor torpedo boats . British submarines generally carried two guns on single mounts. Although it was gradually replaced by the Oerlikon 20 mm cannon , new corvettes were still being fitted with twin Lewises as late as 1942. Lewis guns were also carried by the Royal Air Force 's air-sea rescue launches . American forces used the Lewis gun (in .30-06 calibre) throughout

1560-456: A shaft holding the cam to a set position by pressure from a roller. They were used on early models of Post Office Master clocks to synchronise the clock time with Greenwich Mean Time when the activating follower was pressed onto the cam automatically via a signal from an accurate time source. This type of cam was used for example in mechanical timekeeping clocking-in clocks to drive the day advance mechanism at precisely midnight and consisted of

1638-409: A single rotation of the cylinder and generally provide positive positioning, removing the need for a spring or other provision to keep the follower in contact with the control surface. Applications include machine tool drives, such as reciprocating saws, and shift control barrels in sequential transmissions , such as on most modern motorcycles . A special case of this cam is a constant lead , where

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1716-432: A smooth reciprocating (back and forth) motion in the follower , which is a lever making contact with the cam. A cam timer is similar, and were widely used for electric machine control (an electromechanical timer in a washing machine being a common example) before the advent of inexpensive electronics, microcontrollers , integrated circuits , programmable logic controllers and digital control . The cam can be seen as

1794-666: A typical altitude of 10,000 feet (3,000 m), and firing the solid bullets usually used by aircraft Lewis guns was ineffectual: they made small holes causing inconsequential gas leaks. Britain developed new bullets, the Brock containing spontaneously igniting potassium chlorate , and the Buckingham filled with pyrophoric phosphorus , to set fire to the Zeppelin's hydrogen . These had become available by September 1916. When combined with explosive Pomeroy bullets which ripped open

1872-458: A typical medium machine gun of the era, such as the Vickers machine gun , and was chosen in part because, being more portable than a heavy machine gun, it could be carried and used by one soldier. BSA even produced at least one model (the "B.S.A. Light Infantry Pattern Lewis Gun", which lacked the aluminium barrel shroud and had a wooden fore grip) designed as a form of automatic rifle . During

1950-462: Is a rotating or sliding piece in a mechanical linkage used especially in transforming rotary motion into linear motion. It is often a part of a rotating wheel (e.g. an eccentric wheel) or shaft (e.g. a cylinder with an irregular shape) that strikes a lever at one or more points on its circular path. The cam can be a simple tooth, as is used to deliver pulses of power to a steam hammer , for example, or an eccentric disc or other shape that produces

2028-432: Is mechanical analog computation and special functions in control systems. A face cam that implements three outputs for a single rotational input is the stereo phonograph , where a relatively constant lead groove guides the stylus and tonearm unit, acting as either a rocker-type (tonearm) or linear (linear tracking turntable) follower, and the stylus alone acting as the follower for two orthogonal outputs to representing

2106-603: Is not known for certain whether these were the Savage-made weapons being trans-shipped through the UK, or a separate batch of UK-produced units. White armies in Northwest Russia received several hundred Lewis guns in 1918–1919. British Mark IV tanks used the Lewis, replacing the Vickers and Hotchkiss used in earlier tanks. The Lewis was chosen for its relatively compact magazines, but the ventilation system inside

2184-626: The Birmingham Small Arms Company Limited (BSA) in an effort to overcome some of the production difficulties of the weapon. The Belgians bought a small number of Lewis guns in 1913, using the .303 British round and, in 1914, BSA purchased a licence to manufacture the Lewis machine gun in England, which resulted in Lewis receiving significant royalty payments and becoming very wealthy. Lewis and his factory moved to England before 1914, away from possible seizure in

2262-657: The British during the course of the war. In addition to their reserve weapon role in the UK, they also saw front-line use with the Dutch, British, Australian, and New Zealand forces in the early years of the Pacific campaign against the Japanese. The Lewis gun saw continued service as an anti-aircraft weapon during the war; in this role, it was credited by the British for bringing down more low-flying enemy aircraft than any other AA weapon. Peter White indicates that his battalion of

2340-577: The British government, and ordered another 10,000 weapons from Savage Arms in the US. The US government was unwilling to supply the Tsarist Russian government with the guns and some doubt exists as to whether they were actually delivered, although records indicate that 5,982 Savage weapons were delivered to Russia by 31 March 1917. The Lewis guns supplied by Britain were dispatched to Russia in May 1917, but it

2418-608: The King's Own Scottish Borderers was still using the Lewis on Universal Carriers in 1945. Royal Naval Commandos were also designated use of the weapon for their beach parties. At the start of the Second World War, the Lewis was the Royal Navy 's standard close-range air defence weapon. It was installed on major warships, armed trawlers and defensively equipped merchant ships . It was often used in twin mountings and

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2496-573: The Lewis gun during the Second World War by BSA was over 145,000 units, a total of 3,550 guns were produced by the Savage Arms Co. for US service: 2,500 in .30-06 and 1,050 in .303 British calibre. A commercial venture in 1921 by the Birmingham Small Arms Company was a version which fired the 12.7×81mm (0.5-inch Vickers) ammunition, intended for use against aircraft and tanks. At around the same time, BSA developed

2574-554: The Light Infantry Model which had a 22-round magazine and a wooden fore-stock in place of the radiator fins and shroud; it was intended to be used in a similar way to the Browning Automatic Rifle . Another development was a twin Lewis for aircraft use in which the bodies of the two weapons were joined side-by-side and the drum magazines were mounted vertically, one on each side. None of these projects

2652-425: The Second World War. The Lewis gun was gas operated . A portion of the expanding propellant gas was tapped off from the barrel, driving a piston to the rear against a spring. The piston was fitted with a vertical post at its rear which rode in a helical cam track in the bolt, rotating it at the end of its travel nearest the breech. This allowed the three locking lugs at the rear of the bolt to engage in recesses in

2730-526: The US II Corps attached to the British Army were equipped with the gun. The US Army eventually adopted the Browning Automatic Rifle in 1917 (although it was September 1918 before any of the new guns reached the front). The US Navy and Marine Corps continued to use the .30-06 calibre Lewis until the early part of the Second World War. The Russian Empire purchased 10,000 Lewis guns in 1917 from

2808-655: The US. The Lewis was produced by BSA and Savage Arms during the war, and although the two versions were largely similar, enough differences existed to stop them being completely interchangeable, although this had been rectified by the time of the Second World War . The major difference between the two designs was that the BSA weapons were chambered for .303 British ammunition, whereas the Savage guns were chambered for .30-06 cartridges, which necessitated some difference in

2886-726: The United States though not adopted there, the design was finalised and mass-produced in the United Kingdom, and widely used by troops of the British Empire during the war. It had a distinctive barrel cooling shroud (containing a finned breech-to-muzzle aluminium heat sink to cool the gun barrel), and top-mounted pan magazine . The Lewis served until the end of the Korean War , and was widely used as an aircraft machine gun during both World Wars, almost always with

2964-523: The Vickers by a ratio of about 3:1. The Lewis gun was the first machine gun fired from an aeroplane; on 7 June 1912, Captain Charles Chandler of the US Army fired a prototype Lewis gun from the foot-bar of a Wright Model B Flyer. Lewis guns were used extensively on British and French aircraft during the First World War, as either an observer's or gunner's weapon or an additional weapon to

3042-414: The audio signals. These motions are in a plane radial to the rotation of the record and at angles of 45 degrees to the plane of the disk (normal to the groove faces). The position of the tonearm was used by some turntables as a control input, such as to turn the unit off or to load the next disk in a stack, but was ignored in simple units. This type of cam, in the form of a symmetric heart, is used to return

3120-417: The base (given) and r that of the tip circle (required): The most commonly used cam is the cam plate (also known as disc cam or radial cam ) which is cut out of a piece of flat metal or plate. Here, the follower moves in a plane perpendicular to the axis of rotation of the camshaft. Several key terms are relevant in such a construction of plate cams: base circle , prime circle (with radius equal to

3198-409: The cam is used to provide a mechanical advantage in forcing the window shut, and also provides a self-locking action, like some worm gears , due to friction. Face cams may also be used to reference a single output to two inputs, typically where one input is the rotation of the cam and the other is the radial position of the follower. The output is parallel to the axis of the cam. These were once common

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3276-465: The cam. The output is radial to the cylinder. These were once common for special functions in control systems, such as fire control mechanisms for guns on naval vessels and mechanical analog computers. An example of a cylindrical cam with two inputs is provided by a duplicating lathe , an example of which is the Klotz axe handle lathe, which cuts an axe handle to a form controlled by a pattern acting as

3354-653: The chief of the Ordnance Department. Lewis became frustrated with trying to persuade the U.S. Army to adopt his design, claiming that he was "slapped by rejections from ignorant hacks", and retired from the army. Lewis left the United States in 1913 and went to Belgium, where he established the Armes Automatique Lewis company in Liège to facilitate commercial production of the gun. Lewis had been working closely with British arms manufacturer

3432-415: The complete function, and in this case, the function generally needs to be invertible so that the groove does not self intersect, and the function output value must differ enough at corresponding rotations that there is sufficient material separating the adjacent groove segments. A common form is the constant lead cam, where the displacement of the follower is linear with rotation, such as the scroll plate in

3510-503: The cooling shroud removed, as air flow during flight offered sufficient cooling. A predecessor to the Lewis gun incorporating the principles upon which it was based was designed by Ferdinand Mannlicher . The Lewis gun was invented by U.S. Army colonel Isaac Newton Lewis in 1911, based on initial work by Samuel Maclean. Despite its origins, the Lewis gun was not initially adopted by the U.S. military, most likely because of political differences between Lewis and General William Crozier ,

3588-483: The envelopes, they proved very successful, and Lewis guns loaded with a mixture of Pomeroy, Brock and Buckingham ammunition were often employed for balloon-busting against German Zeppelins, other airships and Drache barrage balloons. On the French Nieuport 11 and later Nieuport 17 sesquiplanes , a Lewis gun was mounted above the top wing (in a similar way as fitted to the British S.E.5a ) – sometimes on

3666-608: The event of a German invasion. The onset of the First World War increased demand for the Lewis gun, and BSA began production, under the designation "Model 1914". The design was officially approved for service on 15 October 1915 under the designation "Gun, Lewis, .303-cal." No Lewis guns were produced in Belgium during the war; all manufacture was carried out by BSA in England and the Savage Arms Company in

3744-420: The fact that it is useless for setting up a barrage, and also that the system of air cooling employed does not allow of more than 12 magazines being fired continuously'. He records its weight as 26 lbs unloaded and 30 + 1 ⁄ 2 lbs loaded (though later he mentions that it weighed 35 lbs loaded), and that it had 47 cartridges in a fully loaded magazine; also that it was supported by a bipod in front and by

3822-430: The final portion of the run the profile of the non-roller cam rose more than the other causing the solid follower to take the weight. A linear cam is one in which the cam element moves in a straight line rather than rotates. The cam element is often a plate or block but may be any cross-section. The key feature is that the input is a linear motion rather than rotational. The cam profile may be cut into one or more edges of

3900-713: The first days of the war, the Belgian Army had put in service 20 prototypes (5 in 7.65×53mm and 15 in .303) for the defense of Namur . The United Kingdom officially adopted the Lewis gun in .303 British calibre for land and aircraft use in October 1915. The weapon began to be issued to the British Army 's infantry battalions on the Western Front in early 1916 as a replacement for the heavier and less mobile Vickers machine gun, which had been withdrawn from

3978-411: The gun fired, the bolt recoiled and the cog was turned, tightening the spring until the resistance of the spring had reached the recoil force of the bolt assembly. At that moment, as the gas pressure in the breech fell, the spring unwound, turning the cog, which, in turn, wound the operating rod forward for the next round. As with a clock spring, the Lewis gun recoil spring had an adjustment device to alter

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4056-430: The gun's body to lock it into place. The post also carried a fixed firing pin , which protruded through an aperture in the front of the bolt, firing the next round at the foremost part of the piston's travel. The gun's aluminium barrel-shroud caused the muzzle blast to draw air over the barrel and cool it, due to the muzzle-to-breech, radially finned aluminium heat sink within the shroud's barrel, and protruding behind

4134-519: The infantry for use by the specialist Machine Gun Corps . The US Navy and Marine Corps followed in early 1917, adopting the M1917 Lewis gun (produced by the Savage Arms Co.), in .30-06 calibre. Notes made during his training in 1918 by Arthur Bullock, a private soldier in the 2/4th Oxfordshire and Buckinghamshire Light Infantry , record that the chief advantage of the gun was 'its invulnerability' and its chief disadvantages were 'its delicacy,

4212-739: The latter half of the Western Han Dynasty (206 BC – 8 AD) as recorded in the Huan Zi Xin Lun. Complex pestles were also mentioned in later records such as the Jin Zhu Gong Zan and the Tian Gong Kai Wu, amongst many other records of water-driven pestles. During the Tang dynasty, the wooden clock within the water-driven astronoical device, the spurs inside a water-driven armillary sphere, the automated alarm within

4290-476: The magazine, feed mechanism, bolt, barrel, extractors, and gas operation system. Savage did make Lewis guns in .303 British calibre, though. The Model 1916 and Model 1917 were exported to Canada and the United Kingdom, and a few were supplied to the US military, particularly the Navy. The Savage Model 1917 was generally produced in .30-06 calibre. A number of these guns were supplied to the UK under lend-lease during

4368-514: The more common Vickers. The Lewis's popularity as an aircraft machine gun was partly due to its low weight, the fact that it was air-cooled and that it used self-contained 97-round drum magazines. Because of this, the Lewis was first mounted on the Vickers F.B.5 "Gunbus", which was probably the world's first purpose-built combat aircraft when it entered service in August 1914, replacing the Vickers machine gun used on earlier experimental versions. It

4446-453: The operator's shoulder at the rear. About six months into his service, Bullock was sent on Lewis gun refresher course at La Lacque, and he recalled that the rigour of the training meant that 'everyone passed out 100 percent efficient, the meaning of which will be appreciated when I say that part of the final test was to strip down the gun completely and then, blindfolded, put those 104 parts together again correctly in just one minute.' The gun

4524-496: The pilot and just above its V-8 engine , could also use one or two Lewis guns mounted on the forward crossbar of its cabane structure, between the top wing panels, as an anti-Zeppelin measure. A few of the Dolphins in use with No. 87 Squadron RAF in the summer of 1918, alternatively mounted their twin Lewises atop the lower wings just inboard of the inner wing struts for an additional pair of forward-firing machine guns; in such

4602-412: The position of the follower is linear with rotation, as in a lead screw. The purpose and detail of implementation influence whether this application is called a cam or a screw thread, but in some cases, the nomenclature may be ambiguous. Cylindrical cams may also be used to reference an output to two inputs, where one input is the rotation of the cylinder and the other is the position of the follower along

4680-399: The profile is treated as a large base circle and a small tip circle, joined by a common tangent, giving lift L , the relationship can be calculated, given the angle φ between one tangent and the axis of symmetry ( φ being ⁠ π / 2 ⁠ − ⁠ θ / 2 ⁠ ), while C is the distance between the centres of the circles (required), and R is the radius of

4758-439: The propeller arc of such aircraft; only the unusual French SPAD S.A "pulpit plane" which possessed a unique hinged gunner's nacelle immediately ahead of the propeller (and the pilot), and the British pusher fighters Vickers F.B.5 , Airco D.H.2 , Royal Aircraft Factory F.E.2 and F.E.8 could readily use the Lewis as direct forward-firing armament early in the war. Some British single-engined tractor configuration fighters used

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4836-506: The recoil resistance for variations in temperature and wear. The Lewis design proved reliable and was even copied by the Japanese and used extensively by them during the Second World War. The gun's cyclic rate of fire was about 500–600 rounds per minute. A recoil enhancer was added to the 1918 aircraft gun variant (and refitted to many 1917 models) which increased the rate of fire to about 800 rounds per minute. The ground use versions weighed 28 lb (12.7 kg), only about half as much as

4914-419: The shroud's aft end, running lengthwise in contact with the gun barrel (somewhat like the later American M1917/18 Marlin-Rockwell machine gun 's similar gun barrel cooling design) from the "bottleneck" near the shroud's muzzle end and protruding externally behind the shroud's rear end. Some discussion occurred over whether the shroud was necessary: in the Second World War, many old aircraft guns that did not have

4992-438: The sum of the follower radius and the base circle radius), pitch curve which is the radial curve traced out by applying the radial displacements away from the prime circle across all angles, and the lobe separation angle ( LSA – the angle between two adjacent intake and exhaust cam lobes). The base circle is the smallest circle that can be drawn to the cam profile. A once common, but now outdated, application of this type of cam

5070-763: The tank caused the airflow to be reversed through the Lewis cooling jacket, resulting in hot air and fumes being blown into the gunner's face. As soon as an improved belt feed for the Hotchkiss was developed, the Lewis was replaced by them in later tank models. As their enemies used the mobility of the gun to ambush German raiding parties, the Germans nicknamed the Lewis "the Belgian Rattlesnake". They used captured Lewis guns in both World Wars, and included instruction in its operation and care as part of their machine-gun crew training. Despite costing more than

5148-550: The time (such as an ambidexterous magazine release), the U.S. Army still chose to adopt the BAR. A short-barrelled light machine gun variant was developed at the start of the Second World War . It came with a hand guard and was fed from a 30-round Bren magazines; however, it was decided by the British authorities to concentrate production on the Bren, which had the advantage of a changeable barrel. Cam (mechanism) A cam

5226-749: The top of the gasbag. By the Second World War, the British Army had replaced the Lewis gun with the Bren gun for most infantry use. As an airborne weapon, the Lewis was largely supplanted by the Vickers K , a weapon that could achieve over twice the rate of fire of the Lewis. In the crisis following the Fall of France, where a large part of the British Army's equipment had been lost up to and at Dunkirk, stocks of Lewis guns in both .303 and .30-06 were hurriedly pressed back into service, primarily for Home Guard , airfield defence and anti-aircraft use. 58,983 Lewis guns were taken from stores, repaired, refitted and issued by

5304-405: The tube/heatsink cooling system on their deck-mounted AA-configuration Lewis guns. The Lewis gun used a pan magazine holding 47 or 97 rounds. Pan magazines hold the ammunition nose-inwards toward the center, in a radial fan. Unlike the more common drum magazines , which hold the rounds parallel to the axis and are fed by spring tension, pan magazines are mechanically indexed. The Lewis magazine

5382-534: The tubing were issued to antiaircraft units of the British Home Guard and to British airfields, and others were used on vehicle mounts in the Western Desert; all were found to function properly without it, which led to the suggestion that Lewis had insisted on the cooling arrangement largely to show that his design was different from Maclean's earlier prototypes. Only the Royal Navy retained

5460-494: The various parts. A cylindrical cam or barrel cam is a cam in which the follower rides on the surface of a cylinder. In the most common type, the follower rides in a groove cut into the surface of a cylinder. These cams are principally used to convert rotational motion to linear motion perpendicular to the rotational axis of the cylinder. A cylinder may have several grooves cut into the surface and drive several followers. Cylindrical cams can provide motions that involve more than

5538-440: The war. The US Navy used the weapon on armed merchant cruisers, small auxiliary ships, landing craft and submarines. The US Coast Guard also used the Lewis on their vessels. It was never officially adopted by the US Army for anything other than aircraft use. The Germans used captured British Lewis guns during the war under the designation MG 137(e) , whilst the Japanese copied the Lewis design and employed it extensively during

5616-625: The war; it was designated the Type 92 and chambered for a 7.7 mm rimmed cartridge that was interchangeable with the .303 British round. The Lewis was officially withdrawn from British service in 1946, but continued to be used by forces operating against the United Nations in the Korean War . It was also used against French and US forces in the First Indochina War and the subsequent Vietnam War . Total production of

5694-417: The weight to be taken over and supported by a solid follower with a sharp edge. This ensured that the weight dropped at a precise moment, enabling accurate timing. This was achieved by the use of two snail cams mounted coaxially with the roller initially resting on one cam and the final solid follower on the other but not in contact with its cam profile. Thus the roller cam initially carried the weight, until at

5772-471: Was accepted by any armed forces. Lewis had also experimented with lighter, 30-06 calibre, box magazine-fed infantry rifle variants intended for shoulder or hip fire as a competition to the BAR. They were dubbed "Assault Phase Rifle" – what could be understood as the first use of the term "Assault Rifle", despite the weapon being, by today's designation, a battle rifle. Despite being three pounds lighter than it and loaded with very forward-thinking features for

5850-514: Was also fitted on two early production examples of the Bristol Scout C aircraft by Lanoe Hawker in mid-1915, mounted on the port side and firing forwards and outwards at a 30° angle to avoid the propeller arc. The problem in mounting a Lewis to fire forward in most single-engined tractor configuration fighters was due to the open bolt firing cycle of the Lewis, which prevented it from being synchronized to fire directly forward through

5928-480: Was automatic machine tool programming cams. Each tool movement or operation was controlled directly by one or more cams. Instructions for producing programming cams and cam generation data for the most common makes of machine, were included in engineering references well into the modern CNC era. This type of cam is used in many simple electromechanical appliances controllers , such as dishwashers and clothes washing machines, to actuate mechanical switches that control

6006-402: Was driven by a cam on top of the bolt which operated a pawl mechanism via a lever. An interesting point of the design was that it did not use a traditional helical coiled recoil spring, but used a spiral spring, much like a large clock spring, in a semicircular housing just in front of the trigger. The operating rod had a toothed underside, which engaged with a cog which wound the spring. When

6084-550: Was operated by a team of seven. Bullock was the First Lewis Gunner who carried the gun and a revolver, while 'The Second Gunner carried a bag containing spare parts, and the remaining five members of the team carried loaded pans of ammunition'. Bullock noted, 'all could fire the gun if required, and all could effect repairs in seconds'. Bullock provides several vivid descriptions of the gun's use in combat. For example, on 13 April 1918 he and his fellow soldiers intercepted

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