A latch or catch (called sneck in Northern England and Scotland) is a type of mechanical fastener that joins two (or more) objects or surfaces while allowing for their regular separation. A latch typically engages another piece of hardware on the other mounting surface. Depending upon the type and design of the latch, this engaged bit of hardware may be known as a keeper or strike .
51-457: [REDACTED] Look up hasp in Wiktionary, the free dictionary. HASP may refer to: Homeowners Affordability and Stability Plan , a U.S. program announced on February 18, 2009, by U.S. President Barack Obama Houston Automatic Spooling Priority , a system program for IBM System/360 and IBM System/370 mainframe computer systems Hasp key ,
102-638: A ( F A ⋅ e A ⊥ ) − b ( F B ⋅ e B ⊥ ) = a F A − b F B , {\displaystyle F_{\theta }=\mathbf {F} _{A}\cdot {\frac {\partial \mathbf {v} _{A}}{\partial {\dot {\theta }}}}-\mathbf {F} _{B}\cdot {\frac {\partial \mathbf {v} _{B}}{\partial {\dot {\theta }}}}=a(\mathbf {F} _{A}\cdot \mathbf {e} _{A}^{\perp })-b(\mathbf {F} _{B}\cdot \mathbf {e} _{B}^{\perp })=aF_{A}-bF_{B},} where F A and F B are components of
153-419: A beam or rigid rod pivoted at a fixed hinge , or fulcrum . A lever is a rigid body capable of rotating on a point on itself. On the basis of the locations of fulcrum, load and effort, the lever is divided into three types . It is one of the six simple machines identified by Renaissance scientists. A lever amplifies an input force to provide a greater output force, which is said to provide leverage , which
204-547: A Hardware Against Software Piracy copy-protection dongle See also [ edit ] Hasp , part of a latch Topics referred to by the same term [REDACTED] This disambiguation page lists articles associated with the title HASP . If an internal link led you here, you may wish to change the link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=HASP&oldid=1214418871 " Category : Disambiguation pages Hidden categories: Short description
255-494: A Norfolk latch, the handle is fitted to a backplate independently of the thumb piece. Introduced around 1800–1820, Norfolk latches, originating in the English county of the same name, differ from the older Suffolk latch, which lacked a back plate to which the thumbpiece is attached. A crossbar , sometimes called a bolt or draw bolt , is a historically common and simple means of barring a door. In its most primitive form it employs
306-413: A bolt on its inboard end and pivoted up and down into open cleats, making it a form of latch . A "draw bolt" style closure adds a handle for sliding its bolt - the source of the term "bolting a door". A variant with a slot in the handle for dropping it over a hasp to secure it with a lock is known as an aldrop. Most modern draw bolts are made of metal, and may be used to secure a door from the outside or
357-401: A button-activated latch. Likewise a ballistic knife uses a strong latch to restrain a powerful spring from firing the blade as a projectile until triggered by opening the latch. A gravity knife relies on a latch to hold the folding blade in an open position once released. A butterfly knife uses a single latch to hold the folding blade both open and closed, depending on the position of
408-458: A cabin hook in such a situation, one should keep in mind that a fire-resistant door is an expensive and heavy item, and it only works as a fire door if it is closed during a fire. To hold an often heavy fire door open simply, electromagnetic door holders are used that release when a building's fire alarm system is activated. As cabin hooks must be released manually, they are impractical for fire doors. Also named draw latch or draw catch. It has
459-405: A claw or a loop that catches the strike plate (named catch plate in this case) when reaching a certain position. A pawl is a latch that will allow movement in one direction, but prevents return motion. It is commonly used in combination with a ratchet wheel. A latch of some type is typically fitted to a door or window . Many types of weaponry incorporate latches with designs unique to
510-427: A door open, like on ships to prevent doors from swinging and banging against other woodwork as the ship moves due to wave action. This usage spread also to other domains, where a door was required to be held open or a self-closing device is used to close the door. Many buildings are built with fire-resistant doors to separate different parts of buildings and to allow people to be protected from fire and smoke. When using
561-504: A foot pedal was used for the earliest horizontal frame loom . In Mesopotamia (modern Iraq) c. 3000 BC , the shadouf , a crane-like device that uses a lever mechanism, was invented. In ancient Egypt , workmen used the lever to move and uplift obelisks weighing more than 100 tons. This is evident from the recesses in the large blocks and the handling bosses which could not be used for any purpose other than for levers. The earliest remaining writings regarding levers date from
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#1732858056827612-410: A hammer to fire the new round. Break open actions are universal in double-barrelled shotguns , double-barrelled rifles and combination guns , and are also common in single shot rifles, pistols , and shotguns , and can also be found in flare guns , grenade launchers , air guns and some older revolver designs. Several latch designs have been used for loading revolvers . In a top-break revolver,
663-431: A hinge, or pivot, called a fulcrum. The ideal lever does not dissipate or store energy, which means there is no friction in the hinge or bending in the beam. In this case, the power into the lever equals the power out, and the ratio of output to input force is given by the ratio of the distances from the fulcrum to the points of application of these forces. This is known as the law of the lever . The mechanical advantage of
714-468: A knife of this type may require significantly more force than the weapons variety as an added safety feature. Crossbows incorporate a type of latch to hold the drawn bowstring prior to firing. Automobiles incorporate numerous special-purpose latches as components of the doors, hood/bonnet , trunk/boot door , seat belts , etc. On passenger cars, a hood may be held down by a concealed latch. On race cars or cars with aftermarket hoods (that do not use
765-446: A lever can be determined by considering the balance of moments or torque , T , about the fulcrum. If the distance traveled is greater, then the output force is lessened. T 1 = F 1 a , T 2 = F 2 b {\displaystyle {\begin{aligned}T_{1}&=F_{1}a,\quad \\T_{2}&=F_{2}b\!\end{aligned}}} where F 1
816-415: A lever is the ratio of output force to input force. M A = F 2 F 1 = a b . {\displaystyle MA={\frac {F_{2}}{F_{1}}}={\frac {a}{b}}.\!} This relationship shows that the mechanical advantage can be computed from ratio of the distances from the fulcrum to where the input and output forces are applied to the lever, assuming
867-405: A plank or beam held by or placed onto open cleats on a door, which is shifted to be held fast by a corresponding cleat on an adjacent jamb. A crossbar for double doors employs the same principle, but, in most cases, must be manually set in place and removed due to its width being greater than both doors. A crossbar for a single jamb may be "captured" on the door by U-shaped bails, or anchored by
918-423: A rigid bar connected to a ground frame by a hinged joint called a fulcrum. The lever is operated by applying an input force F A at a point A located by the coordinate vector r A on the bar. The lever then exerts an output force F B at the point B located by r B . The rotation of the lever about the fulcrum P is defined by the rotation angle θ in radians. Let the coordinate vector of
969-404: A secure bond between cylinder and frame. To fire a revolver, generally the hammer is first manually cocked and latched into place. The trigger, when pulled, releases the hammer, which fires the round in the chamber. Various types of knives with folding or retractable blades rely on latches for their function. A switchblade uses an internal spring to produce the blade which is held in place by
1020-482: A simple thumb-actuated lever and commonly used to hold wooden gates and doors closed. The Suffolk latch originated in the English county of Suffolk in the 16th century and stayed in common use until the 19th century. They have recently come back into favour, particularly in traditional homes and country cottages. They were common from the 17th century to around 1825, and their lack of a back plate made them different from
1071-415: A weightless lever and no losses due to friction, flexibility or wear. This remains true even though the "horizontal" distance (perpendicular to the pull of gravity) of both a and b change (diminish) as the lever changes to any position away from the horizontal. Levers are classified by the relative positions of the fulcrum, effort and resistance (or load). It is common to call the input force "effort" and
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#17328580568271122-413: Is mechanical advantage gained in the system, equal to the ratio of the output force to the input force. As such, the lever is a mechanical advantage device , trading off force against movement. The word "lever" entered English around AD 1300 from Old French : levier . This sprang from the stem of the verb lever , meaning "to raise". The verb, in turn, goes back to Latin : levare , itself from
1173-432: Is a single-throw bolt. The bolt can be engaged in its strike plate only after the door is closed. The locking mechanism typically prevents the bolt from being retracted by force. A slam latch uses a spring and is activated by the shutting or slamming of a door. Like all latches, a slam latch is a mechanism to hold a door closed. The slam latch derives its name from its ability to slam doors and drawers shut without damaging
1224-491: Is different from Wikidata All article disambiguation pages All disambiguation pages hasp A latch is not the same as the locking mechanism of a door or window, although often they are found together in the same product. Latches range in complexity from flexible one-piece flat springs of metal or plastic, such as are used to keep blow molded plastic power tool cases closed, to multi-point cammed latches used to keep large doors closed. A deadbolt latch
1275-428: Is given by: M A = F B F A = a b . {\displaystyle MA={\frac {F_{B}}{F_{A}}}={\frac {a}{b}}.} This is the law of the lever , which was proven by Archimedes using geometric reasoning. It shows that if the distance a from the fulcrum to where the input force is applied (point A ) is greater than the distance b from fulcrum to where
1326-399: Is needed. Electronic cam locks are an alternative to mechanical cam locks. The appearance of the electronic cam lock is similar to the mechanical cam lock, but it is different in the lock cylinder. The keyhole of a mechanical cam lock is usually the same as an ordinary padlock. A physical key is used to unlock the lock. The physical key has a notch or slot corresponding to the obstacle in
1377-411: Is that in some cases the occupant may believe the latch is secure (e.g., by hearing a characteristic click) when in fact it is not. A parking pawl is a device that latches the transmission on automatic vehicles when put in 'park'. A spring latch (in this case an over-center-latch) is used to hold the walls of a springform pan in place. Lever A lever is a simple machine consisting of
1428-481: Is the generalized coordinate that defines the configuration of the lever, and the generalized force associated with this coordinate is given by F θ = F A ⋅ ∂ v A ∂ θ ˙ − F B ⋅ ∂ v B ∂ θ ˙ =
1479-445: Is the input force to the lever and F 2 is the output force. The distances a and b are the perpendicular distances between the forces and the fulcrum. Since the moments of torque must be balanced, T 1 = T 2 {\displaystyle T_{1}=T_{2}\!} . So, F 1 a = F 2 b {\displaystyle F_{1}a=F_{2}b\!} . The mechanical advantage of
1530-422: The eardrum to the oval window of the cochlea . The lever is a movable bar that pivots on a fulcrum attached to a fixed point. The lever operates by applying forces at different distances from the fulcrum, or a pivot. As the lever rotates around the fulcrum, points further from this pivot move faster than points closer to the pivot. Therefore, a force applied to a point further from the pivot must be less than
1581-463: The 3rd century BC and were provided, by common belief, by the Greek mathematician Archimedes , who famously stated "Give me a lever long enough and a fulcrum on which to place it, and I shall move the world." Autumn Stanley argues that the digging stick can be considered the first lever, which would position prehistoric women as the inventors of lever technology. A lever is a beam connected to ground by
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1632-451: The 3rd class lever. A compound lever comprises several levers acting in series: the resistance from one lever in a system of levers acts as effort for the next, and thus the applied force is transferred from one lever to the next. Examples of compound levers include scales, nail clippers and piano keys. The malleus , incus and stapes are small bones in the middle ear , connected as compound levers, that transfer sound waves from
1683-514: The adjective levis , meaning "light" (as in "not heavy"). The word's primary origin is the Proto-Indo-European stem legwh- , meaning "light", "easy" or "nimble", among other things. The PIE stem also gave rise to the English word "light". The earliest evidence of the lever mechanism dates back to the ancient Near East c. 5000 BC , when it was first used in a simple balance scale . In ancient Egypt c. 4400 BC ,
1734-435: The belt which constrains the occupant to the body of the car. Particularly in rear seats slightly different latches may be used for each seat in order to prevent adjacent seatbelts from being attached to the wrong point. Inertial seatbelt release is a potential circumstance where, in a collision, the seatbelt latch can unintentionally come loose leading to potential injury of the passenger. An additional risk of seatbelt latches
1785-422: The cam lock, allowing it to rotate freely in the lock. Different from mechanical cam locks, electronic cam locks use an electronic key to unlock. The key needs to be programmed which contains the user, unlocking date, and time period. The electronic cam lock has no mechanical keyhole, only three metal contacts are retained. When unlocking, the three contacts on the head end of the electronic key are in contact with
1836-450: The factory latch system) the hood may be held down by hood pins. The term Nader bolt is a nickname for the bolt on vehicles that allows a hinged door to remain safely latched and closed. It is named after consumer rights advocate and politician Ralph Nader , who in 1965 released the book Unsafe at Any Speed which claimed that American cars were fundamentally flawed with respect to operator safety. Latches in seatbelts typically fasten
1887-421: The force located at a point closer in, because power is the product of force and velocity. If a and b are distances from the fulcrum to points A and B and the force F A applied to A is the input and the force F B applied at B is the output, the ratio of the velocities of points A and B is given by a/b , so we have the ratio of the output force to the input force, or mechanical advantage,
1938-400: The forces that are perpendicular to the radial segments PA and PB . The principle of virtual work states that at equilibrium the generalized force is zero, that is F θ = a F A − b F B = 0. {\displaystyle F_{\theta }=aF_{A}-bF_{B}=0.\,\!} Thus, the ratio of the output force F B to
1989-540: The frame is hinged at the bottom front of the cylinder . The frame is in two parts, held together by a latch on the top rear of the cylinder. For a swing out cylinder, the cylinder is mounted on a pivot that is coaxial with the chambers, and the cylinder swings out and down. Some designs, such as the Ruger Super Redhawk or the Taurus Raging Bull , use a latches at the front and rear of the cylinder to provide
2040-542: The fulcrum to the input point A and to the output point B , respectively. Now introduce the unit vectors e A and e B from the fulcrum to the point A and B , so r A − r P = a e A , r B − r P = b e B . {\displaystyle \mathbf {r} _{A}-\mathbf {r} _{P}=a\mathbf {e} _{A},\quad \mathbf {r} _{B}-\mathbf {r} _{P}=b\mathbf {e} _{B}.} The velocity of
2091-450: The handles; by rotating 180 degrees the same latch can be used in either configuration. Butterfly knife latches have numerous variations, including magnetic variants and some which can be opened via a spring when the handles are squeezed together. Utility knives also often use a latch to hold a folding knife both open and closed. This allows it to be locked in orientation to the handle when in use, but also safely stowed otherwise. To open
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2142-418: The in. A cabin hook is a hooked bar that engages into a staple. The bar is usually attached permanently to a ring or staple that is fixed with screws or nails to woodwork or a wall at the same level as the eye screw. The eye screw is usually screwed into the adjacent wall or onto the door itself. Used to hold a cupboard , door or gate open or shut. A cabin hook is used in many situations to hold
2193-426: The input force F A is obtained as M A = F B F A = a b , {\displaystyle MA={\frac {F_{B}}{F_{A}}}={\frac {a}{b}},} which is the mechanical advantage of the lever. This equation shows that if the distance a from the fulcrum to the point A where the input force is applied is greater than the distance b from fulcrum to
2244-438: The latch. A slam latch is rugged and ideal for industrial, agricultural and construction applications. A cam lock is a type of latch consisting of a base and a cam . The base is where the key or tool is used to rotate the cam, which is what does the latching. Cams can be straight or offset; offset cams are reversible. Commonly found on garage cabinets, file cabinets, tool chests, and other locations where privacy and security
2295-473: The later, and neighbouring Norfolk latch (introduced 1800–1820). Both the Suffolk latch and Norfolk latch are thought to have been named by architectural draughtsman William Twopenny (1797–1873). Many of these plates found their way into America and other parts of the world. A Norfolk latch is a type of latch incorporating a simple thumb-actuated lever and commonly used to hold wooden gates and doors closed. In
2346-409: The output force "load" or "resistance". This allows the identification of three classes of levers by the relative locations of the fulcrum, the resistance and the effort: These cases are described by the mnemonic fre 123 where the f fulcrum is between r and e for the 1st class lever, the r resistance is between f and e for the 2nd class lever, and the e effort is between f and r for
2397-399: The output force is applied (point B ), then the lever amplifies the input force. On the other hand, if the distance a from the fulcrum to the input force is less than the distance b from the fulcrum to the output force, then the lever reduces the input force. The use of velocity in the static analysis of a lever is an application of the principle of virtual work . A lever is modeled as
2448-416: The point P that defines the fulcrum be r P , and introduce the lengths a = | r A − r P | , b = | r B − r P | , {\displaystyle a=|\mathbf {r} _{A}-\mathbf {r} _{P}|,\quad b=|\mathbf {r} _{B}-\mathbf {r} _{P}|,} which are the distances from
2499-562: The points A and B are obtained as v A = θ ˙ a e A ⊥ , v B = θ ˙ b e B ⊥ , {\displaystyle \mathbf {v} _{A}={\dot {\theta }}a\mathbf {e} _{A}^{\perp },\quad \mathbf {v} _{B}={\dot {\theta }}b\mathbf {e} _{B}^{\perp },} where e A and e B are unit vectors perpendicular to e A and e B , respectively. The angle θ
2550-453: The three contacts on the electronic cam lock. At this time, the key will supply power to the electronic cam lock and read the ID number of the electronic cam lock for verification and match. If successful, the lock can be unlocked. The emergence of electronic cam locks aims to improve the safety and functionality of traditional mechanical cam locks. A Suffolk latch is a type of latch incorporating
2601-412: The weapon. Firearms require specialized latches used during loading and firing of the weapon. A break-action firearm is one whose barrels are hinged and a latch is operated to release the two parts of the weapon to expose the breech and allow loading and unloading of ammunition. It is then closed and re-latched prior to firing. A separate operation may be required for the cocking and latching-open of
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