KR20020001835A - Actuator latch for disc drive - Google Patents

Abstract

A latch mechanism is disclosed for latching an actuator assembly of a disk drive to a standby position. The latch mechanism includes a latch body having a pivot point rotatable at a pivot pin integrally connected to the disk drive, the latch body having a center of gravity substantially near the pivot point. The latch body has a moment of inertia, J _L , which is approximately equal to J _A , the moment of inertia of the actuator multiplied by the gear ratio GR _{L / A} between the latch body and the actuator. The latch body includes a pair of arms that meet at the pivot point and a latch section latched to a latch member attached to one end of the actuator. The latch body also includes a plurality of ferromagnetic bowls attached to each arm. The latch mechanism also includes a magnet connected to the disk drive, which rotates the latch body as it is located near the pair of arms to attract the ferromagnetic bowl.

Description

Actuator Latch for Disk Drives {ACTUATOR LATCH FOR DISC DRIVE}

One important element of a computer system is a device for storing data. Computer systems have several different places where data can be stored. In computer systems, a common place to store large amounts of data is a disk drive. The most basic components of a disk drive are a rotating information storage disk, an actuator for moving a transducer over the disk, and electrical circuitry used to write data to and read data from the disk. The disk drive also includes circuitry for encoding data, which allows data to be successfully retrieved and written to the disk surface. The microprocessor controls most of the operation of the disk drive as well as the operation of carrying data from the computer to return data to the computer or to store such data on the disk.

Transducers, also referred to as sliders, are typically located on small ceramic blocks, which are aerodynamically designed to float above the disc. The slider moves on the disc in relation to the disc. Most sliders have an air-bearing surface ("ABS") including a rail and a cavity between the rails. As the disk rotates, air is dragged between the rail and the disk surface to generate pressure, which forces the head away from the disk. At the same time, air can quickly pass through the cavity or stagnate within the air bearing surface, creating a negative pressure area. Negative pressure or suction cancels the pressure generated on the rails. The slider is also attached to the rod spring, which generates a force that guides the slider toward the disk surface. As the various forces are in equilibrium, the slider is floated to a specific desired height of injury on the surface of the disc. The float height is the distance between the disk surface and the conversion head, which is typically the thickness of an air lubrication film. This thin film eliminates friction and consequently eliminates wear that occurs when the transition head and the disk come into mechanical contact while the disk is rotating. In some disc drives, the slider passes through a lubrication layer rather than floating on the surface of the disc.

Data representing the information is stored on the surface of the storage disk. The disc drive system reads tracks on the storage disc and writes information to the tracks. Transducers attached to the sliders in the form of read / write heads are located on both sides of the storage disc to read or write information on the storage disc when the transducer is correctly positioned on one of the designated tracks on the surface of the storage disc. This is also referred to as the transducer moving to the target track. As the storage disc is rotated and the read / write head is correctly positioned on the target track, the read / write head can store data as a track by writing data representing information onto the storage disc. Similarly, reading data on a storage disk is accomplished by placing the read / write head on the target track and reading the data stored on the storage disk. To write data to or read data from different tracks, the read / write head moves across the tracks radially to the selected target track. Data is divided on tracks or sorted together. In some disc drives, the tracks are multiple concentric tracks. In other disk drives, a continuous spiral is a track on one side of the disk drive. Servo feedback information is used to accurately position the transducer. The actuator assembly is moved with the servo information to the required position and fixed very accurately during reading and writing.

Methods for positioning transducers can generally be classified into two categories. Disc drives with linear actuators generally move the transducer linearly over various tracks on the information storage disc along a radial line. The disc drive also has a rotary actuator mounted to the base of the disc drive for the arcuate operation of the transducer across the tracks of the information storage disc. The rotary actuator positions the transducer by rotating it to a specific position on the information recording disc. Rotary actuators position the transducer quickly and accurately.

Typically, the rotary actuator is rotatably attached to the shaft via a bearing cartridge, which generally comprises one or more sets of ball bearings. The shaft may be attached to the base and attached to the top cover of the disc drive. The yoke is attached to the actuator. The voice coil is attached to the yoke at one end of the rotary actuator. The voice coil is used to rotate the actuator and is part of the voice coil motor to which the transducer or transducers are attached. The permanent magnet is attached to the cover of the base and the disk drive. The voice coil motor driving the rotary actuator includes a voice coil and a permanent magnet. Since the voice coil is fitted to the magnet and yoke assembly that effect the magnetic field, current can be applied to the voice coil to drive the transducer to locate the target track.

When power is cut off from the disk drive, the disk stops spinning. This means that the slider / head assembly stops injuries and returns to the surface of the disc. Most disc drives have a specific landing zone on the disc surface for the slider to land on. The landing zone is typically on the outer or inner part of the disk surface and is designed such that the head can contact the landing zone without damaging the surface of the disk. Once landed, the actuator stays in position or "parked" within the landing zone so that the head stays.

It is important to keep the head and actuator in the standby position because the voice coil motor can no longer control the actuator if power is cut off from the disk drive. Thus, if an impact is applied to the disk drive, the actuator arm can drift to the disk. This can cause permanent damage to the disk. In the past, actuator latches, such as those discussed in Cheng Patent Publication No. 5,381,290, have been used to maintain the position of the actuator after power is disconnected from the disk drive.

However, as computers become smaller and more portable, disk drives have also become smaller and coupled to smaller computers. These disk drives are subject to large rotating shocks due to their small size and the impact they receive as they run. In addition, as the transducer is designed to float closer to the disk surface, even minor scratches on the disk surface can cause permanent damage, since the transducer can be more scratched and damage the disk.

Thus, there is a need for an actuator latch that can run under large linear and rotational impacts. It is also desirable for the latch mechanism to meet a minimum cost.

Thus, there is a need for a disk drive that includes an actuator latch that can maintain the actuator even when subjected to very large rotational impacts and that is easily manufactured and assembled. This will reduce the risk of the transducer damaging the disk surface. As a result, the disk drive will be more reliable during the drive life.

The present invention relates to the field of mass storage devices. More particularly, the present invention relates to an apparatus and method for latching an actuator assembly of a disk drive.

1 is a perspective view of a disk drive with multiple disk stacks,

2 is a plan view of one embodiment of a disk drive assembly with an actuator assembly in accordance with the present invention;

3 is an isometric view of one embodiment of an actuator latch in accordance with the present invention;

4 is an inverted isometric view of the actuator latch of FIG. 3, FIG.

5 is a conceptual diagram of a computer system.

The present invention provides a latch mechanism for latching an actuator assembly of a disk drive in a standby position. In one embodiment, the latch mechanism comprises a latch body, the latch body having a pivot point that is rotatable at a pivot pin integrally connected to the disk drive, and the latch body has a gravity center substantially at the pivot point. The latch body has an moment of inertia J _L , which is approximately equal to the result of multiplying the moment of inertia J _A of the actuator by the gear ratio GR _{L / A} between the latch body and the actuator. [J _L x J _A x GR _LA ]. In another embodiment, the latch body includes a pair of arms that meet at the pivot point and a latch section for latching on the actuator.

In one embodiment, the present invention provides a disk drive having a rotatable actuator attached to a base. The actuator includes a latch member attached to one end and a transducer attached to the other end. The actuator has a moment of inertia, J _A. The disk drive also includes a latch mechanism for latching the actuator in the standby position. The latch mechanism includes a latch body having a pivot point rotatable at a pivot pin integrally connected to the base. The latch body is substantially gatneunde the J _L of the center of gravity and the moment of inertia around the pivot point, which is equal to the product of the gear ratio in GR _{L / A} between edaga of J _A the moment of inertia of the actuator latch body and the actuator results and approximately Do.

Characteristically, the present invention includes an actuator latch that is capable of securing the actuator in the standby position even when the disk drive is subjected to very large rotary shocks and / or linear shocks, and is easy to manufacture and assemble. Thus, the risk of the transducer damaging the disk surface is reduced.

In the following detailed description of the preferred embodiments, reference is made to the drawings, which are attached in form of parts of embodiments and illustrated by specific embodiments in practice of the invention. It will be appreciated that other embodiments may be utilized and may vary structurally without departing from the scope of the present invention.

The invention described in this application is useful for the mechanical form of a disk drive. The present invention is also useful for all types of disk drives, including hard disk drives, zip drives, floppy disk drives and any other type of drive, where it would be desirable to unload the transducer from the surface and wait. will be. 1-3 show a typical disk drive 100 with one embodiment of a latch mechanism 200. As shown in FIG. The disk drive 100 includes a housing or base 112 and a cover 114. Base 112 and cover 114 form a disc enclosure. An actuator assembly 120 is rotatably attached to the actuator shaft 118 of the base 112. Actuator assembly 120 includes an E-block or comb type structure 122 having a plurality of arms 123. A rod beam or rod spring 124 is attached to the split arm 123 on the comb 122. Load beams or load springs are also referred to as suspensions. A slider 126 loaded with a magnetic transducer 150 is attached to the end of each load spring 124. Slider 126 with transducer 150 forms what is previously called the head several times. It should be noted that many sliders have one transducer 150 and this is shown in the figure. It should also be noted that the invention is equally applicable to sliders with one or more transducers, such as MR or magneto resistive heads, where one transducer 150 is generally used for reading and the other One is usually used for writing. At the opposite end of the rod spring 124 and the slider 126 of the actuator arm assembly 120 is a voice coil 128.

The first magnet 130 and the second magnet 131 are attached to the inside of the base 112. As shown in FIG. 1, the second magnet 131 is coupled to the cover 114. The first and second magnets 130, 131 and the voice coil 128 are important elements of the voice coil motor that exerts a force to rotate the actuator assembly 120 around the actuator shaft 118. In addition, the base 112 is attached to the spindle motor. The spindle motor includes a rotation called spindle hub 133. In this particular disk drive, the spindle motor is inside the hub. In FIG. 1, a number of disks 134 are attached to the spindle hub 133. In other disk drives, a single disk or a different number of disks can be attached to the hub. The invention described herein is equally applicable to a disk drive having a single disk as well as a disk drive having a plurality of disks. The invention described herein can also be applied to a disk drive having a spindle motor inside or below the hub 133.

Each arm 123 of the E-block or comb assembly 122 has two load springs, except for the arms 123 at the top and bottom of the E-block 122. In this particular disk drive 100, for the top and bottom fingers of two E-blocks 122, the slider has only one load spring 124, which means that the top and bottom fingers of the stack of discs 134 This is because it is used for the top surface of the top disk and the bottom surface of the bottom disk. Slider 126 attached to load spring 124 includes a magnetic transducer that magnetizes the surface of disk 134 to display and store desired data. As is well known in the art of disc drives, each disc has a series of concentric circular tracks in which magnetized information is stored. The slider 126 and the magnetic transducer coupled therein move over the surface of the particular disk 134 so that the magnetic representation of the data can be stored in any track on the disk 134. In this particular disk drive 100, the transducer action rotates around the actuator shaft 118. Rotary actuator arm assembly 120 repositions slider 126 and transducers thereon over the surface of disk 134.

Actuator assembly 120 has a pivot point 260 that rotates around the shaft during retrieval where the transducer 150 moves between tracks on the disc 134. Actuator 120 has a moment of inertia J _A with respect to pivot point 260. Actuator 120 is driven by the voice coil motor during retrieval. When power is removed from disk drive 100, disk 134 stops rotating and transducer 150 returns to the disk surface. As is well known in the art, an electro-motive force (EMP) returning from the spindle is typically used to rotate the actuator so that when the transducer 150 lands, the transducer is in the landing zone of the disk 134. 234 is positioned above.

The actuator 120 also includes a latch member 270. The latch member 270 is generally located at one end of the actuator 120 opposite the end where the transducer is received. The latch member 270 is for latching the actuator with the latch mechanism 200 when the disk drive is powered down and the converter is waiting. The latch mechanism 200 applies a latching force to the latch member 270 to prevent the actuator assembly 120 from rotating to the surface of the disk 130 when the disk drive 100 is impacted.

2-4 show in detail an exemplary embodiment of the latch mechanism 200. The latch mechanism 200 includes a latch body 210. In a typical embodiment, the latch body 210 is a molded plastic member. In addition, the latch body 210 may have a plastic appearance molded entirely with the inner metal core. In another embodiment of the present invention, the latch body 210 may be a two-piece body having a weight body for attaching to the core body and the core body to provide the required center of gravity and moment of inertia for the body and This will be explained later.

In a typical embodiment, the latch body 210 includes a pair of arms 305 and 306. Arms 305 and 306 extend from the central pivot point 219 of the body 210. Pivot point 219 is the major axis in latch body 210 that rotates with respect to pivot pin 220, which is attached to base 112 of disk drive 100. In general, there is a latch section 310 at the center between arms 305 and 306. Some latch sections 310 are formed by the notches or wall portions 311 of the arm 305 and the notches or wall portions 312 of the arms 306. The latch section 310 is designed to correspond correspondingly with the latch member 270 of the actuator 120. When the actuator 120 rotates to the standby position, the latch member 270 latches correspondingly to the latch section 310, thereby preventing rotation of the actuator until the latch is released.

In a typical embodiment, arm 305 includes a attracting member, such as a pair of ferromagnetic or other magnetizable bowls 320 and 321. The balls 320, 321 are located at one end of the arm 305. The ferromagnetic members 320 and 321 are attracted to a stop member, such as a magnet 130 attached to the base 112 of the disk drive 100. In a typical embodiment, the magnet 130 is a permanent magnet strong enough to attract the balls 320 and 321 as the balls 320 and 321 gradually rotate toward the magnet. This is because the latch member 270 of the actuator corresponds to the inside of the latch section and applies a rotational force to the latch body 210 so that the rotating arm 305 gradually moves the magnet 130 when the actuator 120 moves to the standby position. This causes the magnet 130 to apply a attracting force to the balls 320 and 321. Arm 305 includes a member 323 for leaning against magnet 130 to provide a rest position with respect to the latch mechanism.

Arm 306 also includes an attracting member, such as ferromagnetic bowl 322. Bowl 322 is attracted to a stop member, such as magnet 130. In a typical embodiment, the disk drive includes only one magnet 130 to attract ferromagnetic bowls on each arm. There may also be two or more separate magnets to provide attraction. The magnet 130 has a force large enough to attract the ball 322 when the ball 322 approaches the magnet within a predetermined distance. Typically, this occurs when power is applied to the disk drive 100 and the voice coil motor begins to rotate the actuator 12 and then applies an open rotational force to the latch body 210. This attractive action rotates the latch body 210 around the pivot pin 219 to keep the latch in the open position. In various embodiments, attracting members, such as permanent magnets and / or electromagnets and magnetizable balls or other ferromagnetic members, are possible other alternatives within the scope of the present invention for the latched latch 200.

The configuration and design of the latch body 210 is designed to include the arms 305 and 306 and the bowls 320-322 so that the center of gravity of the latch body 210 is as centered on the pivot point 219 as possible. Thus no linear acceleration or impact on the latch will rotate the body. For example, in FIG. 2, impact force 235 may be applied to the disk drive. This force 235 will result in a linear acceleration element and an angular acceleration element on the latch body. As is known, the linear element of force on the body acts through the center of gravity of the body. Since the body 210 is designed to have a center of gravity at or near the pivot point 219, the linear element of force will not have any rotational effect on the body. This keeps the latch in the blocking position and prevents the actuator 120 from being released.

In addition, the shape and mass of the latch body 210 imparts an inertial moment J _L to the body around the pivot point 219 of the body. The moment of inertia of a body is a measure of resistance that causes the body to rotate around a given axis. The moment of inertia of any body, such as latch mechanism 200 or actuator 120, is determined by integrating the square of the distance of each arbitrary mass away from the axis of rotation. Thus, the moment of inertia increases as the mass moves away from the axis of rotation. In the present system, the moment of inertia of the latch body (J _L) is designed to be substantially the same as the result obtained by multiplying a gear ratio (GR _{L / A)} between the actuator 120 and the latch body 210 to the actuator moment of inertia (J _A) . That is, J _L ≒ J _A × GR _{L / A.}

The gear ratio GR _{L / A} between two bodies represents the relative amount of rotation moment between two connected and rotating members. This is defined as the ratio of the distance of the gear arm of the latch body 210 divided by the gear arm distance of the actuator 120. The gear arm distance of the latch body 210 is the distance between the pivot point 219 and the contact point 240 (see FIG. 2) in which the latch member 270 contacts the latch section 310 of the latch body. Thus, the gear ratio GR _{L / A} is the ratio of the distance between the pivot point and the contact point.

Since the moment of inertia of the latch body 210 is designed as J _L ≒ J _A × GR _{L / A} , the actuator mechanism 200 of the present invention can be operated even when the actuator assembly 120 is subjected to a large rotational shock in both directions. Fix it. For example, referring to FIG. 2, the impact force 235 against the disk drive causes rotational acceleration α in both the latch body 210 and the actuator 120. This is indicated by arrows 236 and 237. This rotational acceleration causes a clockwise torque, T = J × α, as is known on the two bodies.

Clockwise torque on actuator 120 will attempt to rotate the actuator to the surface of the disk. However, the actuator is held in position by the latch mechanism 200. In addition, the rotational torque of the actuator 120 means that the latch member 270 of the actuator assembly exerts an open force against the latch body 210 at point 240. This force appears on the latch body 210 as an open torque of T (open) = J _A × α × GR _{L / A.} However, on the latch body 210 there is also a closing torque due to its moment of inertia. This closing torque is T (colse) = J _L × α. It is known to those skilled in the art to maintain a closed latch as J _L > J _A x GR _{L / A.} It is noted here that the magnet 130 also applies a closing torque on the latch body 210. However, at very large rotational accelerations (ie, when α is very high, eg greater than 25 kPa), the magnet 130 itself does not overcome the opening torque applied from the actuator 120 to the latch body 210. .

If another rotational impact is applied to the disk drive 100 (for example, the force indicated as 238 in FIG. 2), the rotational acceleration α of the latch and the actuator will be counterclockwise. In this state, the actuator assembly 120 will have a closing torque due to its moment of inertia, T (colse) = J _L × α. At the same time, the latch body will impose an opening torque T (open) = α J × _L ÷ GR _{L / A} to the actuator 120. As shown therein, the best state in this case is J _L ≤ J _A x GR _{L / A.} Thus, the design of the latch is designed to withstand both directions of rotational shock and the inventors found that the best condition is J _L ≒ J _A × GR _{L / A.}

Thus, characteristically, the mass of the latch body 210 and the shape and design of the arms 305 and 306 provide the moment of inertia J _L to balance the torque applied by the actuator arms in both directions of rotation.

Another feature of this design is that it is necessary to latch the actuator to lock it in the standby position when the power is not applied, but the latch can release the actuator again when power is applied back to the disk drive. Thus, it is not desirable to increase the original mechanical holding force of the latch, since it will be difficult to open when needed. In the present invention, the closing force is provided by the moment of inertia of the latch so that the opening force no longer needs to be large for use after opening.

Characteristically, the present invention provides a disk drive including an actuator latch that can be easily manufactured and assembled, thereby securing the actuator and reapplying power to the drive even when the actuator is subjected to very large rotational and linear shocks. The actuator can be easily released at the time. Thus, the risk of the transducer damaging the disk surface is reduced.

5 is a schematic diagram of a computer system. In particular, the present invention is well suited for use in computer system 2000. Computer system 2000, also called an electronic system or information processing system, includes a central processing unit, memory, and a system bus. The information processing system includes a central processing unit 2004, a random access memory 2032, and a system bus 2030 for communicatively connecting with the central processing unit 2004 and the random access memory 2032. The information processing system 2002 comprises a disk drive device including the ramp described above. The information processing system 2002 may also include a number of peripheral devices such as 2012, 2014, 2016, 2018, 2020, and 2022 that may be attached to the input / output bus 2010 and the input / output bus 2010. Peripheral devices may include such things as hard disk drives, magnetic optical drives, floppy disk drives, monitors, keyboards, and other peripherals. Some types of disc drives may use a method for loading or unloading sliders on the disc surface as described above.

conclusion

In conclusion, the latch mechanism 200 of the disk drive 100 is for latching the actuator assembly 120 of the disk drive 100 to the standby position. The latch mechanism 200 includes a latch body 210 having a pivot point 219 rotatable at a pivot pin 220 integrally connected to the disc drive 100, the latch body 210 being substantially pivot point ( 219), the latch body is approximately equal to the gear ratio GR _{L / A} between the latch body 210 and the actuator 120 multiplied by the moment of inertia J _A of the actuator 120. It has a moment of inertia J _L.

In another embodiment, the latch body 210 includes a pivot point 219 and a pair of arms 305 and 306 that meet at the latch section 310 for latching the actuator.

In one embodiment, the disk drive 100 includes a base 112 and an actuator 120 that is rotatably attached to the base 112. The actuator 120 includes a latch member 270 attached to one end and a transducer 150 attached to the other end. Actuator 120 has a moment of inertia J _A with respect to pivot point 260. The disk drive also includes a latch mechanism 200 for latching the actuator 120 in the standby position. The latch mechanism 200 includes a latch body 210 having a pivot point 219, the latch point 219 being rotatable at a pivot point 220 integrally connected with the base 112. The latch body 210 has a moment of inertia J _A about the center of gravity and the pivot point 219 substantially near the pivot point 219. J _L is approximately equal to the gear ratio GR _{L / A} between the actuator 120 and the latch body 210 multiplied by the moment of inertia J _A.

In one embodiment, the disc drive 100 has a latch having an actuator 120 that is subjected to rotational shock and a means for counteracting the opening torque applied to the latch 20 by the actuator 120 when the actuator is subjected to a rotational impact. 200.

It is to be understood that the foregoing description is illustrative and not restrictive. Many other embodiments will be apparent to those of ordinary skill in the art upon reviewing the above description. The scope of the invention will be determined on the basis of the appended claims as it follows the full scope of equivalents referred to as claims.

Claims (19)

A latching mechanism for latching an actuator of a disk drive in the standby position, The latch mechanism includes a latch body, The latch body has a pivot point that is rotatable on a pivot pin integrally connected to the disk drive, has a center of gravity substantially near the pivot point, and the gear ratio between the latch body and the actuator is applied to the moment of inertia of the actuator. Latch mechanism with approximately the same moment of inertia as the product of multiplication. The latch mechanism of claim 1, wherein the latch body further comprises a pair of arms that meet at the pivot point. 3. The latch mechanism of claim 2 wherein the latch body comprises a latch section for latching the actuator. 2. The latch mechanism of claim 1 further comprising a base and a pivot pin coupled to the base. The latch mechanism of claim 1, wherein the latch body further comprises a pair of arms, wherein the pair of arms meet at the pivot point, and each of the arms comprises a ferromagnetic bowl. 6. The latch mechanism of claim 5 further comprising a magnet coupled to the disk drive to attract the ferromagnetic bowl. The latch body of claim 1, wherein the latch body includes a latch section for latching with the actuator, the gear ratio being a first distance from the latch body pivot point to the latch section from the pivot point of the actuator to the latch section. The latch mechanism that is the same as divided by the second distance of. Bass, An actuator attached to the base at an actuator pivot point, the actuator having a first end and a second end, the latch member attached to one end of the first end or the second end of the actuator and the second end of the actuator. Or an actuator attached to the other end of the second end, the actuator having a moment of inertia with respect to the actuator pivot point, and Has a latch section adapted to correspond to the actuator latch member, is attached to the base at a latch body pivot point, has a center of gravity substantially near the latch body pivot point, and a moment of inertia with respect to the latch body pivot point And a latch mechanism comprising a latch body having a latch mechanism, the latch body moment of inertia comprising a latch mechanism approximately equal to a result of multiplying the gear ratio between the actuator and the latch body by the actuator moment of inertia. The disk drive of claim 8, wherein the latch body is molded plastic material. The disk drive of claim 8, wherein the latch body comprises a metal core molded entirely of plastic material. 9. The disk drive of claim 8, wherein the latch body includes a pair of arms, each of the pair of arms including one or more ferromagnetic members. The disk drive of claim 11, further comprising a magnet coupled to the disk drive to attract the ferromagnetic member. The disk drive of claim 12, wherein the latch body has a sickle shape. 9. The method of claim 8, wherein the gear ratio is the latch gear arm distance divided by the actuator gear arm distance, the actuator arm distance is the distance from the actuator pivot point to one point, and the latch member contacts the latch body latch section, And the latch body gear arm distance is a distance from the latch body pivot point to the one point, the latch member contacting the latch body latch section. 9. The disk drive of claim 8, further comprising a stop member connected to the base to stop the latch body. The disk drive of claim 8, further comprising a pivot pin connected to the base to rotate the latch body. 9. The disk drive of claim 8 wherein the latch body has a first arm and a second arm having the latch body pivot point therebetween. 18. The disk drive of claim 17, wherein the latch section of the latch body is located approximately between the first arm and the second arm. Actuators subjected to rotational shock, and A latch comprising a latch having means for counteracting an opening torque exerted by the actuator to the latch when the actuator is subjected to a rotational impact.