Lever - Revision history

Rphillips52 at 17:15, 5 March 2025

2025-03-05T17:15:41Z

← Older revision		Revision as of 17:15, 5 March 2025
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	=== Barron lock ===		=== Barron lock ===
	In 1778, [[Robert Barron]] patented [BP1200] the principle of all modern mechanical security locks — the double-acting movable detainer. His patent describes 'the gating or racking to allow a stump on the tumbler to pass through the bolt, or an opening in the tumbler to allow a stump on the bolt to pass through.' These two (of several possible) realisations of the double-acting movable detainer principle are now usually described as 'lever locks'. Barron's was the first lever lock that used a stump and gates. This technique requires each lever be moved to a precise distance (typically, height) at which the stump can pass through the gate. Overlifting or underlifting a lever leaves it blocking the stump - hence "Double acting"; older locks' levers only needed to be moved upwards to clear — more than that had no effect, as they had already cleared the obstacle. Barron, and after him his son, and others, used only the arrangement of stumps on the tumblers with gates in the bolt tail. This arrangement would prove in the long run less successful than Barron's other suggestion of a stump on the bolt tail and gates in the tumblers.		In 1778, London locksmith [[Robert Barron]] patented [BP1200] the principle of all modern mechanical security locks — the double-acting movable detainer. His patent describes 'the gating or racking to allow a stump on the tumbler to pass through the bolt, or an opening in the tumbler to allow a stump on the bolt to pass through.' These two (of several possible) realisations of the double-acting movable detainer principle are now usually described as 'lever locks'. Barron's was the first lever lock that used a stump and gates. This technique requires each lever be moved to a precise distance (typically, height) at which the stump can pass through the gate. Overlifting or underlifting a lever leaves it blocking the stump - hence "Double acting"; older locks' levers only needed to be moved upwards to clear — more than that had no effect, as they had already cleared the obstacle. Barron, and after him his son, and others, used only the arrangement of stumps on the tumblers with gates in the bolt tail. This arrangement would prove in the long run less successful than Barron's other suggestion of a stump on the bolt tail and gates in the tumblers.
	The realisation Barron used is practically limited to 4 tumblers, and most locks had only 2. The other arrangement allows an unlimited number of levers to be stacked on the same pivot, blocking the same stump.		The realisation Barron used is practically limited to 4 tumblers, and most locks had only 2. The other arrangement allows an unlimited number of levers to be stacked on the same pivot, blocking the same stump.
	The double-acting movable detainer principle is still in use to this day in lever locks, but also including [[pin-tumbler]] locks by [[Linus_Yale_Jr\|Linus Yale, Jr]], and mechancal combination ~~locks. Indeed, it is the principle of security of all mechanical security~~ locks.		The double-acting movable detainer principle is still in use to this day in lever locks, but also including [[pin-tumbler]] locks by [[Linus_Yale_Jr\|Linus Yale, Jr]], and mechancal combination locks.

	=== Chubb lock ===		=== Chubb lock ===
	[[File:Chubb_lock.jpg\|thumb\|right\|text-top\|300px\|The [[Chubb]] Detector lock.]]		[[File:Chubb_lock.jpg\|thumb\|right\|text-top\|300px\|The [[Chubb]] Detector lock.]]

	In 1818, Charles and [[Jeremiah Chubb]] patented [BP4219] a lock design based on Barron's work. Their version used the placement of stump on the bolt tail and gates in the levers. These levers have 2 pockets, with the bolt stump moving through the gate in the lever fence (or bar) from one pocket to the other, as the bolt moves. This design is commonly associated with the name of Chubb, and is still in use today in many locks. They also added a device called the ''detector'', an extra lever that triggered by overlifting of the main levers. When triggered, the detector would lock the bolt until it was reset [regulated, in Chubbs' word] with a special key. To make it more convenient to use, the Chubb detector lock was modified slightly in 1824 so that it could be reset by the working key, instead of a separate 'regulating' key. The concept of the ‘detector’ was that the lock not only responded to the true key, it also recognised a wrong key or picking attempt, and signalled this to the proper keyholder by a change of state. The concept was invented by Ruxton in 1816 [BP4027] but his realisation was not a practical success. The Chubb lock was the first to have a practical detector, combined with lever tumblers. [[Chubb]] later added false notches or serrations on the fences of the levers which prematurely bound components if tension were applied when the component was in the incorrect position. This anti-picking idea was originally introduced on Bramah locks from 1817, and also used on Anthony Strutt's lever lock of 1819 — the first to use end-gated levers. It was later included in [[security pins]] and many other lock designs.		In 1818, Charles and [[Jeremiah Chubb]] patented [BP4219] a lock design based on Barron's work. Their version used the placement of stump on the bolt tail and gates in the levers, a realisation described by Barron but not used by him. These levers have 2 'H shaped' pockets, with the bolt stump moving through the gate in the lever fence (or bar) from one pocket to the other, as the bolt moves. This design is commonly associated with the name of Chubb, and is still in use today in many locks. They also added a device called the ''detector'', an extra lever that triggered by overlifting of the main levers. When triggered, the detector would lock the bolt until it was reset [regulated, in Chubbs' word] with a special key. To make it more convenient to use, the Chubb detector lock was modified slightly in 1824 so that it could be reset by the working key, instead of a separate 'regulating' key. The concept of the ‘detector’ was that the lock not only responded to the true key, it also recognised a wrong key or picking attempt, and signalled this to the proper keyholder by a change of state. The concept was invented by Ruxton in 1816 [BP4027] but his realisation was not a practical success. The Chubb lock was the first to have a practical detector, combined with lever tumblers. [[Chubb]] later added false notches or serrations on the fences of the levers which prematurely bound components if tension were applied when the component was in the incorrect position. This anti-picking idea was originally introduced on Bramah locks from 1817, and also used on Anthony Strutt's lever lock of 1819 — the first to use end-gated levers. It was later included in [[security pins]] and many other lock designs.
	In 1820, Mallet patented a rotating barrel and curtain that closed off the keyhole when the key was turned and hindered independent movement of picking instruments. This addition helped to prevent [[decoding]]. Patent applications in Britain were not inspected for 'novelty' before 1852, hence an invention could be re-invented and a new patent issued, as happened with the lock barrel and curtain idea. De La Fons would later also be granted a patent for this same idea, in 1846. Although not widely used before 1851, the combined barrel-and-curtain are now commonly used security features of high-security lever locks - the name usually simply abbreviated to 'curtain'.		In 1820, Mallet patented a rotating barrel and curtain that closed off the keyhole when the key was turned and hindered independent movement of picking instruments. This addition helped to prevent [[decoding]]. Patent applications in Britain were not inspected for 'novelty' before 1852, hence an invention could be re-invented and a new patent issued, as happened with the lock barrel and curtain idea. De La Fons would later also be granted a patent for this same idea, in 1846. Although not widely used before 1851, the combined barrel-and-curtain are now commonly used security features of high-security lever locks - the name usually simply abbreviated to 'curtain'.

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	; Levers		; Levers
	: The primary locking component of a lever lock. Each lever is a flat piece of metal with a gate which must be moved to the proper position to allow the stump to pass through and retract or extend the bolt. Each lever is normally impelled by a spring, usually fixed to the lever. Springs are mostly spring steel; brass of phospher bronze are used on some locks for weather resistance. Some levers use a thinned belly section referred to as "conning" to ensure the lever interfaces with the correct bitting area on the key.		: The primary locking component of a lever lock. Each lever is a flat piece of metal with a gate which must be moved to the proper position to allow the stump to pass through and retract or extend the bolt. Each lever is normally impelled by a spring, usually fixed to the lever. Springs are mostly spring steel; brass or phospher bronze are used on some locks for weather resistance. Some levers use a thinned belly section referred to as "conning" to ensure the lever interfaces with the correct bitting area on the key.

	; Stump		; Stump
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	In general, well-made lever locks incorporating several pick-resisting features are likely to be physically stronger and more resistant to manipulation than comparable pin tumbler cylinder locks. They are likely to be larger, and typically have slightly larger keys. Lever locks in widespread use tend to have fewer differs than comparable pin tumbler cylinder locks, although trial of keys is hindered by the greater weight of keys needed and the slower rate at which they can be tested. Keys for different models of lever locks have a considerable variety of sizes, further impeding trial of keys. With less standardisation of lock sizes, lever locks can be more expensive to fit than modern cylinder locks.		In general, well-made lever locks incorporating several pick-resisting features are likely to be physically stronger and more resistant to manipulation than comparable pin tumbler cylinder locks. They are likely to be larger, and typically have slightly larger keys. Lever locks in widespread use tend to have fewer differs than comparable pin tumbler cylinder locks, although trial of keys is hindered by the greater weight of keys needed and the slower rate at which they can be tested. Keys for different models of lever locks have a considerable variety of sizes, further impeding trial of keys. With less standardisation of lock sizes, lever locks can be more expensive to fit than modern cylinder locks.

	The great majority of locks in use are not masterkeyed. Several methods of masterkeying locks have been invented. One- and two-level masterkeying is used for small suites, and has been much used in institutions in the past. Most lever locks are not well-suited to complex large-scale or multi-level masterkeying. Those with [[Detainer Levers]] or other forms of end-gated lever are generally better for this than those with H gate levers.		The great majority of locks in use are not masterkeyed. Several methods of masterkeying lever locks have been invented. One- and two-level masterkeying is used for small suites, and has been much used in institutions in the past. Most lever locks are not well-suited to complex large-scale or multi-level masterkeying. Those with [[Detainer Levers]] or other forms of end-gated lever are generally better for this than those with H gate levers.

	Many security lever locks are well-protected against drilling, so that this attack usually needs more work than most pin tumbler cylinders. Drill points vary from one lock model to another and are not visible externally.		Many security lever locks are well-protected against drilling, so that this attack usually needs more work than most pin tumbler cylinders. Drill points vary from one lock model to another and are not visible externally.

Rphillips52 at 17:06, 5 March 2025

2025-03-05T17:06:19Z

← Older revision		Revision as of 17:06, 5 March 2025
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	A '''lever''' (or '''lever tumbler''') is a [[lock]] design that uses flat pieces of metal (also known as levers) and a [[bolt]] as locking components. In this article, 'lever lock' does not mean a locking lever handle incorporating a cylinder locking device.		A '''lever''' (or '''lever tumbler''') is a [[lock]] design that uses flat pieces of metal (also known as levers) and a [[bolt]] as locking components. In this article, 'lever lock' does not mean a locking lever handle incorporating a cylinder locking device.
	In most designs, the position of the levers prevents the bolt from retracting. When positioned properly, a gate in the lever allows the bolt to move (shot or withdrawn). Lever locks are historically one of the most popular lock designs, but use has declined as less expensive [[pin-tumbler]] locks have gained popularity. Lever locks are popular in Europe (particularly the UK), eastern Europe, and some parts of South America, as residential and commercial [[door]] locks and on [[safe]]s. Safe-deposit boxes in banks around the world use lever designs heavily.		In most designs, the position of the levers prevents the bolt from retracting. When positioned properly, a gate in the lever allows the bolt to move (shot or withdrawn). Lever locks are historically one of the most popular lock designs, but use has declined as less expensive [[pin-tumbler]] locks have gained popularity. Lever locks are popular in Europe (particularly the UK), eastern Europe, and some parts of South America, as residential and commercial [[door]] locks and on [[safe]]s. Safe-deposit boxes in banks around the world use lever designs heavily. Several lever cylinder locking devices have been invented, but few have achieved lasting success in the marketplace. One of the most successful and secure lever cylinder designs is the Ingersoll Impregnable lock.

	__TOC__		__TOC__
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	In 1778, [[Robert Barron]] patented [BP1200] the principle of all modern mechanical security locks — the double-acting movable detainer. His patent describes 'the gating or racking to allow a stump on the tumbler to pass through the bolt, or an opening in the tumbler to allow a stump on the bolt to pass through.' These two (of several possible) realisations of the double-acting movable detainer principle are now usually described as 'lever locks'. Barron's was the first lever lock that used a stump and gates. This technique requires each lever be moved to a precise distance (typically, height) at which the stump can pass through the gate. Overlifting or underlifting a lever leaves it blocking the stump - hence "Double acting"; older locks' levers only needed to be moved upwards to clear — more than that had no effect, as they had already cleared the obstacle. Barron, and after him his son, and others, used only the arrangement of stumps on the tumblers with gates in the bolt tail. This arrangement would prove in the long run less successful than Barron's other suggestion of a stump on the bolt tail and gates in the tumblers.		In 1778, [[Robert Barron]] patented [BP1200] the principle of all modern mechanical security locks — the double-acting movable detainer. His patent describes 'the gating or racking to allow a stump on the tumbler to pass through the bolt, or an opening in the tumbler to allow a stump on the bolt to pass through.' These two (of several possible) realisations of the double-acting movable detainer principle are now usually described as 'lever locks'. Barron's was the first lever lock that used a stump and gates. This technique requires each lever be moved to a precise distance (typically, height) at which the stump can pass through the gate. Overlifting or underlifting a lever leaves it blocking the stump - hence "Double acting"; older locks' levers only needed to be moved upwards to clear — more than that had no effect, as they had already cleared the obstacle. Barron, and after him his son, and others, used only the arrangement of stumps on the tumblers with gates in the bolt tail. This arrangement would prove in the long run less successful than Barron's other suggestion of a stump on the bolt tail and gates in the tumblers.
	The realisation Barron used is practically limited to 4 tumblers, and most locks had only 2. The other arrangement allows an unlimited number of levers to be stacked on the same pivot, blocking the same stump.		The realisation Barron used is practically limited to 4 tumblers, and most locks had only 2. The other arrangement allows an unlimited number of levers to be stacked on the same pivot, blocking the same stump.
	The double-acting movable detainer principle is still in use to this day in lever locks, but also including [[pin-tumbler]] locks by [[Linus_Yale_Jr\|Linus Yale, Jr]].		The double-acting movable detainer principle is still in use to this day in lever locks, but also including [[pin-tumbler]] locks by [[Linus_Yale_Jr\|Linus Yale, Jr]], and mechancal combination locks. Indeed, it is the principle of security of all mechanical security locks.

	=== Chubb lock ===		=== Chubb lock ===
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	In 1818, Charles and [[Jeremiah Chubb]] patented [BP4219] a lock design based on Barron's work. Their version used the placement of stump on the bolt tail and gates in the levers. These levers have 2 pockets, with the bolt stump moving through the gate in the lever fence (or bar) from one pocket to the other, as the bolt moves. This design is commonly associated with the name of Chubb, and is still in use today in many locks. They also added a device called the ''detector'', an extra lever that triggered by overlifting of the main levers. When triggered, the detector would lock the bolt until it was reset [regulated, in Chubbs' word] with a special key. To make it more convenient to use, the Chubb detector lock was modified slightly in 1824 so that it could be reset by the working key, instead of a separate 'regulating' key. The concept of the ‘detector’ was that the lock not only responded to the true key, it also recognised a wrong key or picking attempt, and signalled this to the proper keyholder by a change of state. The concept was invented by Ruxton in 1816 [BP4027] but his realisation was not a practical success. The Chubb lock was the first to have a practical detector, combined with lever tumblers. [[Chubb]] later added false notches or serrations on the fences of the levers which prematurely bound components if tension were applied when the component was in the incorrect position. This anti-picking idea was originally introduced on Bramah locks from 1817, and also used on Anthony Strutt's lever lock of 1819 — the first to use end-gated levers. It was later included in [[security pins]] and many other lock designs.		In 1818, Charles and [[Jeremiah Chubb]] patented [BP4219] a lock design based on Barron's work. Their version used the placement of stump on the bolt tail and gates in the levers. These levers have 2 pockets, with the bolt stump moving through the gate in the lever fence (or bar) from one pocket to the other, as the bolt moves. This design is commonly associated with the name of Chubb, and is still in use today in many locks. They also added a device called the ''detector'', an extra lever that triggered by overlifting of the main levers. When triggered, the detector would lock the bolt until it was reset [regulated, in Chubbs' word] with a special key. To make it more convenient to use, the Chubb detector lock was modified slightly in 1824 so that it could be reset by the working key, instead of a separate 'regulating' key. The concept of the ‘detector’ was that the lock not only responded to the true key, it also recognised a wrong key or picking attempt, and signalled this to the proper keyholder by a change of state. The concept was invented by Ruxton in 1816 [BP4027] but his realisation was not a practical success. The Chubb lock was the first to have a practical detector, combined with lever tumblers. [[Chubb]] later added false notches or serrations on the fences of the levers which prematurely bound components if tension were applied when the component was in the incorrect position. This anti-picking idea was originally introduced on Bramah locks from 1817, and also used on Anthony Strutt's lever lock of 1819 — the first to use end-gated levers. It was later included in [[security pins]] and many other lock designs.
	In 1820, Mallet patented a rotating barrel and curtain that closed off the keyhole when the key was turned and hindered independent movement of picking instruments. This addition helped to prevent [[decoding]]. De La Fons would later also be granted a patent for this same idea, in 1846. Although not widely used before 1851, the combined barrel-and-curtain are now commonly used security features of high-security lever locks - the name usually simply abbreviated to 'curtain'.		In 1820, Mallet patented a rotating barrel and curtain that closed off the keyhole when the key was turned and hindered independent movement of picking instruments. This addition helped to prevent [[decoding]]. Patent applications in Britain were not inspected for 'novelty' before 1852, hence an invention could be re-invented and a new patent issued, as happened with the lock barrel and curtain idea. De La Fons would later also be granted a patent for this same idea, in 1846. Although not widely used before 1851, the combined barrel-and-curtain are now commonly used security features of high-security lever locks - the name usually simply abbreviated to 'curtain'.

	=== Tucker and Reeves ===		=== Tucker and Reeves ===
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	Several anti-pressure devices, and other pick-resisting features, have been invented.		Several anti-pressure devices, and other pick-resisting features, have been invented.
	There have also appeared several lever cylinder locking devices, of which the Ingersoll Impregnable is notable. It has been made under licence in the USA by Sargant & Greenleaf.		There have also appeared several lever cylinder locking devices, of which the Ingersoll Impregnable is notable. It has been made under licence in the USA by Sargant & Greenleaf.
			Several other lock designs have derived from the lever principle, such as the Bauche Monopole and its several versions, and the AVA cylinder mechanism which is also akin to a wafer tumbler lock.
			Several methods of allowing a quick and easy key change have been invented. These locks are mainly used on safes, and in situations where staff changes occur rather frequently. Typically, any of the possible set of keys can lock an unlocked lock, but then only that key combination will unlock it. Such locks were used by Britain's General Post Office on travelling sorting offices, with staff on each shift having their own key to the secure lockers used for high value packets. Today, change key locks are not common, but there are some modern safe locks, whose combination can be changed by the user simply by buying and applying a different key — even quicker and easier than changing a mechanical dial combination safe lock.

	'Simple' should not be equated to 'insecure'. Designs using a double-bitted key with unsprung levers having closed bellies, cheaply made in zinc alloy castings, are widely-used on medium-grade safes in Europe. Lever steps on one bit move the levers, the corresponding steps on the other bit stop the levers moving too far. The levers are end-gated, (allowing a strongly-fixed and well-supported bolt stump) with numerous serrated false notches. Locks of this type are practically very difficult to pick tentatively, and inside a safe door are well-protected against force. Usually, re-lockers are also connected, to frustrate disrupting the lock by force or explosive.		'Simple' should not be equated to 'insecure'. Designs using a double-bitted key with unsprung levers having closed bellies, cheaply made in zinc alloy castings, are widely-used on medium-grade safes in Europe. Lever steps on one bit move the levers, the corresponding steps on the other bit stop the levers moving too far. The levers are end-gated, (allowing a strongly-fixed and well-supported bolt stump) with numerous serrated false notches. Locks of this type are practically very difficult to pick tentatively, and inside a safe door are well-protected against force. Usually, re-lockers are also connected, to frustrate disrupting the lock by force or explosive.
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	Although this describes the typical arrangement, several other realisations also occur.		Although this describes the typical arrangement, several other realisations also occur.

	A stack of levers is placed in the lock. Every lever must be properly moved (typically raised) by the key to allow the bolt stump fixed to the bolt tail to pass through the gates of the levers, retracting or extending the bolt. Each lever may have a different sized belly, or a different gate position to provide [[differs]]. In most realisations, the ~~lever pivots~~, but ~~some~~ in some ralisations they slide.		A stack of levers is placed in the lock. Every lever must be properly moved (typically raised) by the key to allow the bolt stump fixed to the bolt tail to pass through the gates of the levers, retracting or extending the bolt. Each lever may have a different sized belly, or a different gate position to provide [[differs]]. In most realisations, the levers pivot, but in some ralisations they slide.

	See also: [[Detainer Levers]]		See also: [[Detainer Levers]]
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	; Levers		; Levers
	: The primary locking component of lever lock. Each lever is a flat piece of metal with a gate which must be moved to the proper position to allow the stump to pass through and retract or extend the bolt. Each lever is normally impelled by a spring, usually fixed to the lever. Some levers use a thinned belly section referred to as "conning" to ensure the lever interfaces with the correct bitting area on the key.		: The primary locking component of a lever lock. Each lever is a flat piece of metal with a gate which must be moved to the proper position to allow the stump to pass through and retract or extend the bolt. Each lever is normally impelled by a spring, usually fixed to the lever. Springs are mostly spring steel; brass of phospher bronze are used on some locks for weather resistance. Some levers use a thinned belly section referred to as "conning" to ensure the lever interfaces with the correct bitting area on the key.

	; Stump		; Stump
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	; Spacers		; Spacers
	: Spacers are flat (often metal) plates placed between each lever to ensure that each lever is properly raised by each bitting cut. They are not universal, but common in outdoor facing lever locks that require a high degree of reliability, especially in harsh conditions. On some cheaper locks they are replaced by stamped bumps which maintain the spacings without increasing the parts count. It is important that each key step moves only its own lever and not an adjacent one. In handmade locks, this was commonly achieved by making low steps wider, by narrowing adjacent higher steps		: Spacers are flat (often metal) plates placed between each lever to ensure that each lever is properly raised by each bitting cut. They are not universal, but common in machine-made outdoor-facing lever locks that require a high degree of reliability, especially in harsh conditions. On some cheaper locks they are replaced by stamped bumps which maintain the spacings without increasing the parts count. It is important that each key step moves only its own lever and not an adjacent one. In handmade locks, this was commonly achieved by making low key steps wider, by narrowing adjacent higher steps.

	; Barrel and Curtain (now combined and usually referred to simply as 'curtain')		; Barrel and Curtain (now combined and usually referred to simply as 'curtain')
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	Lever locks (in common with other locks) are vulnerable to a variety of attacks, depending on their design. Tentative picking is increasingly difficult as the number of levers increases. Many security locks also incorporate features which hamper manipulation, and additionally, warding is also sometimes used to this end (just as in pin tumbler locks). Tools to pick and decode lever locks are not as widely available as their [[pin-tumbler]] counterparts, largely because the tools required are more laborious to make, and expensive, and are more likely to be specialized to each lock, unlike pin tumbler and wafer tumbler [[picks]]. However, devices do exist and can be effective. Often, more specialised tools are made for a size and design for an individual model of lever lock.		Lever locks (in common with other locks) are vulnerable to a variety of attacks, depending on their design. Tentative picking is increasingly difficult as the number of levers increases. Many security locks also incorporate features which hamper manipulation, and additionally, warding is also sometimes used to this end (just as in pin tumbler locks). Tools to pick and decode lever locks are not as widely available as their [[pin-tumbler]] counterparts, largely because the tools required are more laborious to make, and expensive, and are more likely to be specialized to each lock, unlike pin tumbler and wafer tumbler [[picks]]. However, devices do exist and can be effective. Often, more specialised tools are made for a size and design for an individual model of lever lock.
	In general, well-made lever locks incorporating several pick-resisting features are likely to be physically stronger and more resistant to manipulation than comparable pin tumbler cylinder locks. They are likely to be larger, and typically have slightly larger keys. Lever locks in widespread use tend to have fewer differs than comparable pin tumbler cylinder locks, although trial of keys is hindered by the greater weight of keys needed and the slower rate at which they can be tested. Keys for different models of lever locks have a considerable variety of sizes, further impeding trial of keys.		In general, well-made lever locks incorporating several pick-resisting features are likely to be physically stronger and more resistant to manipulation than comparable pin tumbler cylinder locks. They are likely to be larger, and typically have slightly larger keys. Lever locks in widespread use tend to have fewer differs than comparable pin tumbler cylinder locks, although trial of keys is hindered by the greater weight of keys needed and the slower rate at which they can be tested. Keys for different models of lever locks have a considerable variety of sizes, further impeding trial of keys. With less standardisation of lock sizes, lever locks can be more expensive to fit than modern cylinder locks.

	One- and two-level masterkeying is used for small suites, and has been much used in institutions in the past. Most lever locks are not well-suited to complex large-scale or multi-level masterkeying. Those with [[Detainer Levers]] or other forms of end-gated lever are generally better for this than those with H gate levers.		The great majority of locks in use are not masterkeyed. Several methods of masterkeying locks have been invented. One- and two-level masterkeying is used for small suites, and has been much used in institutions in the past. Most lever locks are not well-suited to complex large-scale or multi-level masterkeying. Those with [[Detainer Levers]] or other forms of end-gated lever are generally better for this than those with H gate levers.

	Many security lever locks are well-protected against drilling, so that this attack usually needs more work than most pin tumbler cylinders. Drill points vary from one lock model to another and are not visible externally.		Many security lever locks are well-protected against drilling, so that this attack usually needs more work than most pin tumbler cylinders. Drill points vary from one lock model to another and are not visible externally.
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	== References ==		== References ==
	<references />		<references />
	PULFORD, Graham (2007). High ~~Security Mechanical Locks~~: ~~An Encyclopedic Reference~~. ISBN 0750684372.		PULFORD, Graham (2007). High security mechanical locks: an encyclopedic reference. ISBN 0750684372.

	== See also ==		== See also ==

Rphillips52 at 16:23, 5 March 2025

2025-03-05T16:23:23Z

← Older revision		Revision as of 16:23, 5 March 2025
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	There have also appeared several lever cylinder locking devices, of which the Ingersoll Impregnable is notable. It has been made under licence in the USA by Sargant & Greenleaf.		There have also appeared several lever cylinder locking devices, of which the Ingersoll Impregnable is notable. It has been made under licence in the USA by Sargant & Greenleaf.

	'Simple' should not be equated to 'insecure'. Designs using a double-bitted key with unsprung levers having closed bellies, cheaply made in zinc alloy castings, are widely-used on medium-grade safes in Europe. Lever steps on one bit move the levers, the corresponding steps on the other bit stop the levers moving too far. The levers are end-gated, (allowing a strongly-fixed and well-supported bolt stump) with numerous serrated false notches. Locks of this type are practically ~~impossible~~ to pick tentatively, and inside a safe door are well-protected against force. Usually, re-lockers are also connected, to frustrate disrupting the lock by force or explosive.		'Simple' should not be equated to 'insecure'. Designs using a double-bitted key with unsprung levers having closed bellies, cheaply made in zinc alloy castings, are widely-used on medium-grade safes in Europe. Lever steps on one bit move the levers, the corresponding steps on the other bit stop the levers moving too far. The levers are end-gated, (allowing a strongly-fixed and well-supported bolt stump) with numerous serrated false notches. Locks of this type are practically very difficult to pick tentatively, and inside a safe door are well-protected against force. Usually, re-lockers are also connected, to frustrate disrupting the lock by force or explosive.

	Many lever locks are less demanding of production precision than cylinder locks, and this has increased the popularity of physically robust lever locks in eastern Europe in the past few decades.		Many lever locks are less demanding of production precision than cylinder locks, and this has increased the popularity of physically robust lever locks in eastern Europe in the past few decades. Lever locks are also (depending on materials used) highly resistant to freezing weather.

	== Principles of Operation ==		== Principles of Operation ==
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	Although this describes the typical arrangement, several other realisations also occur.		Although this describes the typical arrangement, several other realisations also occur.

	A stack of levers is placed in the lock. Every lever must be properly moved (typically raised) by the key to allow the bolt stump fixed to the bolt tail to pass through the gates of the levers, retracting or extending the bolt. Each lever may have a different sized belly, or a different gate position to provide [[differs]].		A stack of levers is placed in the lock. Every lever must be properly moved (typically raised) by the key to allow the bolt stump fixed to the bolt tail to pass through the gates of the levers, retracting or extending the bolt. Each lever may have a different sized belly, or a different gate position to provide [[differs]]. In most realisations, the lever pivots, but some in some ralisations they slide.

	See also: [[Detainer Levers]]		See also: [[Detainer Levers]]
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	: The stump is a protrusion usually fixed to the [[bolt]]. The stump prevents the bolt from being extended or retracted until the levers are properly positioned. Traditional designs have the stump and levers interconnected (pockets are closed, with the stump sitting inside each lever).		: The stump is a protrusion usually fixed to the [[bolt]]. The stump prevents the bolt from being extended or retracted until the levers are properly positioned. Traditional designs have the stump and levers interconnected (pockets are closed, with the stump sitting inside each lever).

	; ~~Washers~~		; Spacers
	: ~~Washers~~ are flat (often metal) plates placed between each lever to ensure that each lever is properly raised by each bitting cut. They are not universal, but common in outdoor facing lever locks that require a high degree of reliability, especially in harsh conditions. On some cheaper locks they are replaced by stamped bumps which maintain the spacings without increasing the parts count.		: Spacers are flat (often metal) plates placed between each lever to ensure that each lever is properly raised by each bitting cut. They are not universal, but common in outdoor facing lever locks that require a high degree of reliability, especially in harsh conditions. On some cheaper locks they are replaced by stamped bumps which maintain the spacings without increasing the parts count. It is important that each key step moves only its own lever and not an adjacent one. In handmade locks, this was commonly achieved by making low steps wider, by narrowing adjacent higher steps

	; Barrel and Curtain (now combined and usually referred to simply as 'curtain')		; Barrel and Curtain (now combined and usually referred to simply as 'curtain')
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	In general, well-made lever locks incorporating several pick-resisting features are likely to be physically stronger and more resistant to manipulation than comparable pin tumbler cylinder locks. They are likely to be larger, and typically have slightly larger keys. Lever locks in widespread use tend to have fewer differs than comparable pin tumbler cylinder locks, although trial of keys is hindered by the greater weight of keys needed and the slower rate at which they can be tested. Keys for different models of lever locks have a considerable variety of sizes, further impeding trial of keys.		In general, well-made lever locks incorporating several pick-resisting features are likely to be physically stronger and more resistant to manipulation than comparable pin tumbler cylinder locks. They are likely to be larger, and typically have slightly larger keys. Lever locks in widespread use tend to have fewer differs than comparable pin tumbler cylinder locks, although trial of keys is hindered by the greater weight of keys needed and the slower rate at which they can be tested. Keys for different models of lever locks have a considerable variety of sizes, further impeding trial of keys.

	One- and two-level masterkeying is used for small suites, and has been much used in institutions in the past. Most lever locks are not well-suited to complex large-scale or multi-level masterkeying. Those with [[Detainer Levers]] are generally better for this than those with H gate levers.		One- and two-level masterkeying is used for small suites, and has been much used in institutions in the past. Most lever locks are not well-suited to complex large-scale or multi-level masterkeying. Those with [[Detainer Levers]] or other forms of end-gated lever are generally better for this than those with H gate levers.

	Many security lever locks are well-protected against drilling, so that this attack usually needs more work than most pin tumbler cylinders. Drill points vary from one lock model to another and are not visible externally.		Many security lever locks are well-protected against drilling, so that this attack usually needs more work than most pin tumbler cylinders. Drill points vary from one lock model to another and are not visible externally.

Mgsecure: PageName/TOC fix

2022-12-19T15:38:18Z

PageName/TOC fix

← Older revision		Revision as of 15:38, 19 December 2022
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	=~~Lever=~~		<span style="font-size: 188%;">{{PAGENAME}}</span>
			----

	A '''lever''' (or '''lever tumbler''') is a [[lock]] design that uses flat pieces of metal (also known as levers) and a [[bolt]] as locking components. In this article, 'lever lock' does not mean a locking lever handle incorporating a cylinder locking device.		A '''lever''' (or '''lever tumbler''') is a [[lock]] design that uses flat pieces of metal (also known as levers) and a [[bolt]] as locking components. In this article, 'lever lock' does not mean a locking lever handle incorporating a cylinder locking device.

Sandplum: /* Components */ adjusted image size

2021-02-09T00:09:07Z

Components: adjusted image size

← Older revision		Revision as of 00:09, 9 February 2021
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	== Components ==		== Components ==
	[[File:drawing_Lever_Lock.gif\|thumb\|right\|text-top\|~~300px~~\|Lever Lock Parts.]]		[[File:drawing_Lever_Lock.gif\|thumb\|right\|text-top\|250px\|Lever Lock Parts.]]

	; Levers		; Levers

Sandplum: /* Components */ added drawing with labeled parts

2021-02-09T00:05:47Z

Components: added drawing with labeled parts

← Older revision		Revision as of 00:05, 9 February 2021
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	== Components ==		== Components ==
			[[File:drawing_Lever_Lock.gif\|thumb\|right\|text-top\|300px\|Lever Lock Parts.]]

	; Levers		; Levers

Sandplum: /* Vulnerabilities */ fixed detainer lever link

2021-02-01T23:56:02Z

Vulnerabilities: fixed detainer lever link

← Older revision		Revision as of 23:56, 1 February 2021
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	In general, well-made lever locks incorporating several pick-resisting features are likely to be physically stronger and more resistant to manipulation than comparable pin tumbler cylinder locks. They are likely to be larger, and typically have slightly larger keys. Lever locks in widespread use tend to have fewer differs than comparable pin tumbler cylinder locks, although trial of keys is hindered by the greater weight of keys needed and the slower rate at which they can be tested. Keys for different models of lever locks have a considerable variety of sizes, further impeding trial of keys.		In general, well-made lever locks incorporating several pick-resisting features are likely to be physically stronger and more resistant to manipulation than comparable pin tumbler cylinder locks. They are likely to be larger, and typically have slightly larger keys. Lever locks in widespread use tend to have fewer differs than comparable pin tumbler cylinder locks, although trial of keys is hindered by the greater weight of keys needed and the slower rate at which they can be tested. Keys for different models of lever locks have a considerable variety of sizes, further impeding trial of keys.

	One- and two-level masterkeying is used for small suites, and has been much used in institutions in the past. Most lever locks are not well-suited to complex large-scale or multi-level masterkeying. Those with [[~~detainers~~]] are generally better for this than those with H gate levers.		One- and two-level masterkeying is used for small suites, and has been much used in institutions in the past. Most lever locks are not well-suited to complex large-scale or multi-level masterkeying. Those with [[Detainer Levers]] are generally better for this than those with H gate levers.

	Many security lever locks are well-protected against drilling, so that this attack usually needs more work than most pin tumbler cylinders. Drill points vary from one lock model to another and are not visible externally.		Many security lever locks are well-protected against drilling, so that this attack usually needs more work than most pin tumbler cylinders. Drill points vary from one lock model to another and are not visible externally.

Sandplum: /* Principles of Operation */ page rename 'detainer levers'

2021-02-01T09:47:57Z

Principles of Operation: page rename 'detainer levers'

← Older revision		Revision as of 09:47, 1 February 2021
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	A stack of levers is placed in the lock. Every lever must be properly moved (typically raised) by the key to allow the bolt stump fixed to the bolt tail to pass through the gates of the levers, retracting or extending the bolt. Each lever may have a different sized belly, or a different gate position to provide [[differs]].		A stack of levers is placed in the lock. Every lever must be properly moved (typically raised) by the key to allow the bolt stump fixed to the bolt tail to pass through the gates of the levers, retracting or extending the bolt. Each lever may have a different sized belly, or a different gate position to provide [[differs]].

	See also: [[~~Detainers~~]]		See also: [[Detainer Levers]]

	<div align="center"><gallery>		<div align="center"><gallery>

Datagram: Upgrading to remove cleanup tag!

2015-02-05T19:57:26Z

Upgrading to remove cleanup tag!

← Older revision		Revision as of 19:57, 5 February 2015
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	=Lever=		=Lever=
	~~{{cleanup}}~~

	A '''lever''' (or '''lever tumbler''') is a [[lock]] design that uses flat pieces of metal (also known as levers) and a [[bolt]] as locking components. In this article, 'lever lock' does not mean a locking lever handle incorporating a cylinder locking device.		A '''lever''' (or '''lever tumbler''') is a [[lock]] design that uses flat pieces of metal (also known as levers) and a [[bolt]] as locking components. In this article, 'lever lock' does not mean a locking lever handle incorporating a cylinder locking device.

NKT: /* Components */

2015-02-03T22:08:11Z

Components

← Older revision		Revision as of 22:08, 3 February 2015
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	; Washers		; Washers
	: Washers are flat (often metal) plates placed between each lever to ensure that each lever is properly raised by each bitting cut. They are not universal, but common in outdoor facing lever locks that require a high degree of reliability, especially in harsh conditions.		: Washers are flat (often metal) plates placed between each lever to ensure that each lever is properly raised by each bitting cut. They are not universal, but common in outdoor facing lever locks that require a high degree of reliability, especially in harsh conditions. On some cheaper locks they are replaced by stamped bumps which maintain the spacings without increasing the parts count.

	; Barrel and Curtain (now combined and usually referred to simply as 'curtain')		; Barrel and Curtain (now combined and usually referred to simply as 'curtain')
	: This is a component used in the keyhole to prevent direct access to the levers after the key or pick is rotated in the lock. When the key turns, the curtain blocks the keyhole. The barrel hampers the ~~independant~~ movements of a 2-in-1 pick of the design originally used by A C Hobbs. This protects against casual manipulation of the levers, but does not preclude [[lockpicking]] attacks completely.		: This is a component used in the keyhole to help prevent direct access to the levers after the key or pick is rotated in the lock. When the key turns, the curtain blocks the keyhole. The barrel hampers the independent movements of a 2-in-1 pick of the design originally used by A C Hobbs. This protects against casual manipulation of the levers, but does not preclude [[lockpicking]] attacks completely.

	== Vulnerabilities ==		== Vulnerabilities ==