GB2472645A

GB2472645A - Latch arrangement having a selective transmission path

Info

Publication number: GB2472645A
Application number: GB0914252A
Authority: GB
Inventors: Robert Frank Tolley
Original assignee: Body Systems USA LLC; Meritor Technology LLC
Current assignee: Body Systems USA LLC
Priority date: 2009-08-14
Filing date: 2009-08-14
Publication date: 2011-02-16
Anticipated expiration: 2029-08-14
Also published as: GB2472645B; GB0914252D0

Abstract

A latch arrangement 10 comprising a transmission path 30 which selectively connects a handle 26, 28, or other manually operable member, to a retaining member, such as a pawl, of a latch bolt 12. The transmission path comprises an intermediate member 34 (shuttle), a first part 32 coupled to the handle, a second part 36 coupled to the pawl. The first and second parts have first and second abutment surfaces 40, 44, respectively which are proximate to the intermediate member when it is in a rest position. When the handle is operated whilst the latch is unlocked the abutment of the first part engages the shuttle and moves it from the rest position to a first actuated position in which it abuts and moves the second part which releases the pawl. When operated whilst the latch is locked the first part engages the shuttle which moves from the rest position to a second actuated position in which it does not engage the second part and the latch remains retained by pawl. Preferably in the unlocked position the shuttle is biased to slide in a first direction (fig.5) by abutments (75, 77, fig.5) and torsion spring whereas in the locked position an electromagnet 72 selectively holds a link (68, fig.5) causing shuttle to pivot in a second direction upon operation of the handle (fig.6).

Description

LATCH ARRANGEMENT

The present arrangement relates to a latch arrangement, in particular a latch arrangement for releasably securing a door, in particular a vehicle door such as a land vehicle, for example, a car.

Car door latch arrangements are known whereby a driver or passenger door can be secured in a closed position by a door latch. The latch can be released by operating either an inside handle or an outside handle.

The door can have various security statuses including locked, super-locked, unlocked. When the door is locked or unlocked it can have the additional security status of child safety on or child safety off.

EP1738307 shows a latch arrangement in which operation of a door handle will release the latch to allow the door to be opened if in the unlocked position, but will not release the latch if in the super-locked condition.

Figure 1 of the present application shows the latch arrangement of EP1738307 in a rest position. In order to release the latch, pawl pin 14 must be moved from the Figure A position to the Figure B position by abutment 22. As shown in Figure 1 (the rest position of the latch arrangement) abutment 22 is remote from pin 14. In order to release the latch, abutment 22 first has to be moved to the position shown in Figure 2 and then must be moved to the position shown in figure 3.

As such, operation of either handle 21 or 22 initially requires movement in order to align abutment 22 with pin 14. Handle 20 or 21 then needs to be pulled further in order to move the pin from the position A to position B. As such, a relatively long handle travel is required.

An object of the present invention is to provide a latch arrangement wherein a shorter handle travel is required to unlatch the latch.

The invention will now be described by way of example only with reference to accompanying drawings in which: FIGURES 1, 2 and 3 show the prior art latch arrangement ofEP1783307, FIGURES 4 to 7 show a first embodiment of a latch arrangement according to the present invention, FIGURES 8 to 11 show a second embodiment of a latch arrangement according to the present invention, FIGURE 12 to 15 show a third embodiment of a latch arrangement according to the present invention, FIGURES 16 to 19 show a fourth embodiment of a latch arrangement according to the present invention, FIGURES 20 to 22 show a fifth embodiment of a latch arrangement according to the present invention.

With reference to Figures 4 to 7, there is shown a latch arrangement 10. The latch arrangement includes a latch bolt 12 in the form of a rotating claw (only shown in figure 4).

The rotating claw 12 is pivotable about pivot 14 to selectively retain or release a striker 16.

As shown in Figure 4, the rotating claw is in a closed position, thereby retaining striker 16.

The rotating claw is held in this closed position by a retaining means in the form of a rotating pawl 18 (only shown in figure 4). As shown in Figure 4, pawl 18 is in a retaining position retaining the claw in its closed position. By rotating the pawl 18 about pivot 20 in an anti-clockwise direction the pawl can be moved to a released position thereby releasing the claw and allowing an associated door 22 (only shown in figure 4) to open. Note that the striker will typically be located on the door frame, for example on the B post of a car. The pawl 18 is operably connected to pawl lifter 24.

The latch arrangement also includes manually operable elements, in this case in the form of an inside door handle 26 and an outside door handle 28 (only shown on figure 4).

A transmission path 30 selectively connects the inside door handle and the outside door handle to the pawl 18. The transmission path 30 (parts of which are shown schematically) is defined by a first part 32, a second part 36 and a shuttle 34.

The first part includes a release lever element 38 having an abutment 40 (also known as a first transmission path abutment.).

The second part includes pawl lifter element 42 having an abutment 44 (also known as a second transmission path abutment).

The shuttle is generally T shaped having a first arm 46, a second arm 48 and a third arm 50.

The first arm includes an abutment 52, also known as a first shuttle abutment. The first arm also includes a pin 54.

The second arm 48 includes an abutment 56, also known as a second shuttle abutment. The abutment 56 is positioned between shuttle teeth 58 and 59 of the shuttle.

The third arm 50 includes a recess 60.

At the confluence of the first, second and third arms, there is a pivot 62 having a pivot axis 63.

A lever 64 is pivotably mounted by pivot 65 on a latch chassis 66 (only part of which is shown and only on figure 4). The lever 64 has a first arm 68 which is pivotably mounted relative to the shuttle via pivot 62. The lever has a second arm 70 at the end of which is a flange 71 made from a piece of magnetic material. The flange 71 projects towards the viewer when viewing Figure 4.

An electro-magnet 72 can selectively hold or release flange 71 as will be further described below.

A toggle 73 is pivotable about axis 74 and is made from a permanent magnet. Operation of the electro-magnet 72 can selectively move the toggle 73 from the position shown in Figure 4 to the position shown in Figure 7. The electro-magnet can also move the toggle from the position shown in Figure 7 to the position shown in Figure 4.

The electro-magnet 72 is mounted on the latch chassis 66 and the toggle 73 is pivotably mounted to the latch chassis 66.

The lever 64 is pivotably mounted to the latch chassis 66 via pivot 65.

Also mounted on the latch chassis 66 are posts 75, 76 and 77. A helical spring 78 has a series of coils 79 mounted around post 76. The helical spring 78 includes tangentially oriented arms 80 an 81. Arm 80 engages post 75 and arm 81 engages pin 54. The helical spring 78 is under tension and hence arm 81 biases pin 54 generally to the right when viewing the figures.

Operation of the latch arrangement is as follows.

As shown in Figure 4, the latch arrangement is in a rest position. As shown in Figure 5, the latch arrangement is shown in a first actuated position. As shown in Figure 6 and 7, the latch arrangement is in a second actuated position.

In summary, when the latch arrangement is in an unlocked condition, manual actuation of either the inside door handle 26 or the outside door handle 28 causes the release lever element 38 to move to the left, to the position shown in Figure 5 thereby causing the shuttle to move to the left resulting in the pawl lifter 24 moving to the left thereby moving the rotating pawl to its release position and unlatching the latch.

When the door is in a locked condition, operation of either the inside door handle 26 or the outside door handle 28 moves the release lever element 38 to the position shown in Figure 6 and Figure 7. As can be seen, under these circumstances, the shuttle rotates about axis 63 and the pawl lifter is not moved, and hence the latch is not unlatched.

In more detail, operation of the latch arrangement when in an unlocked condition is as follows:-For the purposes of explanation of the operation when the latch arrangement is unlocked, it is assumed that the electro-magnet 72 as shown in Figure 1 is deactivated, i.e. no electric current is passing through the coils of the electro-magnet and hence there is no magnetic attraction between the electro-magnet and the magnetic flange 71. Note also that the toggle 73 is rotated to an anti-clockwise position as shown in figure 4 (when compared with Figure 7). As such, lever 64 is free to move, and in particular is free to pivot about pivot 65.

Manual actuation of either the inside door handle 26 or the outside door handle 28 will cause the first part of the transmission path to move the release lever element from the position shown in Figure 4 to the position shown in Figure 5. This results in the abutment 40 engaging and applying a force to abutment 52. This force causes the shuttle to translate to the left when viewing Figure 4 such that the abutment 56 engages the abutment 44 on the pawl lifter. Under these circumstances the abutment 44 will be positioned between the shuttle tooth 58 and the shuttle tooth 59. The pawl lifter is constrained to move in the direction of arrow A (see Figure 5). As such, the shuttle tooth 58 ensures that the abutment 56 remains in engagement with the abutment 44 and hence the shuttle moves to the position shown in Figure 5 whereupon the latch is released. As mentioned above, because the lever 64 is free to rotate about pivot 65, it has no influence on the ability of the shuttle to move generally leftwardly when viewing Figures 4 and 5.

Posts 75 and 77 act as guides for the second and third arms of the shuttle. Once the latch has been released, the operator will release handle 26 or 28 as appropriate and the tension in the helical spring 78 will push pin 54 generally to the right thereby returning the shuttle and lever 64 to the position shown in Figure 4. Subsequent closing of the door will return the pawl 18 and claw 12 to the position shown in figure 4.

Operation of the latch arrangement when in a locked condition is as follows:-For the purposes of explaining the operation in a locked condition, it is now assumed that the electro-magnet 72 as shown in Figure 1 is in a powered condition and as such it attracts and holds flange 71 in the position shown in Figure 4. Under these circumstances, manual actuation of either the outside or the inside door handle will move the release lever element 38 from the position shown in Figure 4 to the position shown in Figure 6. However, since the lever 64 is prevented from pivoting about pivot 65, the pivot 62 is unable to move and hence the pivot axis 63 is unable to move. Thus, the shuttle is forced to rotate in an anti-clockwise direction about the now fixed pivot axis 63. This causes the abutment 56 to rotate away from the abutment 44 and hence the pawl lifter is not caused to be moved and as a result the latch arrangement will not open.

Releasing of the appropriate handle 26 or 28 will cause the helical spring 78 to push the pin 54 generally rightwardly resulting in the shuttle returning to the position shown in Figure 4.

Figure 7 shows an alternative way of locking the latch arrangement. As will be appreciated by comparing Figure 7 to Figure 5, the toggle 73 in the Figure 7 position has been rotated clockwise such that an end 73A of toggle 73 faces the flange 71 and blocks movement of the flange in a generally rightwardly direction, in other words end 73A prevents anti-clockwise rotation of the lever 64 about pivot 65. The end 73A therefore acts to prevent movement of pivot 62 and in particular pivot axis 63. Thus, whenever the toggle is in the position shown in Figure 7 (whether or not the electro-magnet is actuated) the pivot axis 63 will be fixed thereby preventing the shuttle from translating to the left and hence preventing opening of the latch.

As will be appreciated, when in the rest position (figure 4) the abutment 56 (second shuttle abutment) is positioned proximate abutment 44 (second transmission path abutment) these two abutments are separated by a distance only slightly greater than the height of shuttle tooth 58. As such, when the latch arrangement is in the unlocked condition relatively little movement is required of the outside door handle 28 or the inside door handle 26 before the rotating pawl starts to disengage from the pawl. This can be contrasted with the arrangement shown in EP1783307 wherein a significant amount of movement of the inside or outside door handle must occur before the abutment 22 aligns with pin 14. As such, in order to unlatch a latch according to the present invention, less handle movement is required when compared with the handle movement required to open prior art latch EP1783307.

As will be appreciated, in the rest position shown in Figure 4, the abutment 56 is proximate the abutment 44 and this can be contrasted with the rest position of prior art EP1783307 shown in Figure 1 where the abutment 22 is remote from pin 14.

It is clear from Figure 4 that abutment 56 faces abutment 44 when in the rest position.

It is also clear from Figure 4 that abutment 56 is in close proximity to abutment 44.

Depending upon the friction coefficient of the material from which abutment 56 and abutment 44 are made, in some embodiments tooth 58 may not be required and hence abutment 56 can be positioned even closer to abutment 44 than as shown in Figure 4. Indeed, in some embodiments it is possible to arrange for abutment 56 to be in contact with abutment 44 when in the rest position.

As will be appreciated from Figure 4, no significant movement of shuttle is required in order for abutment 56 to contact abutment 44. It will also be appreciated that because the abutment 56 is so close to abutment 44 the movement of abutment 44 is substantially similar to the movement of abutment 56. This can be contrasted with the movement of pin 14 of EP1783307 when moving from position A to position B compared with the movement of abutment 22 when moving from the Figure 1 position to the Figure 2 position. Movement of the abutment 22 of EP1783307 is initially generally arcuate and then generally linear, whereas the movement of pin 14 is only generally linear.

It will also be appreciated that there is no significant change in orientation of shuttle 34 between the position shown in Figure 4 and the moment at which abutment 56 engages abutment 44. The shuttle merely translates the short distance required to close the gap between abutment 56 and abutment 44. This can be contrasted with the significant change in orientation of lever 28 of EP1783307 since, as shown in Figure 1, it is pointing generally downwardly to the right, and as shown in Figure 2, it is pointing generally upwardly to the right.

With reference to Figures 8 to 11, there is shown a second embodiment of a latched arrangement 110 in which components that fulfil the same function as those of latch arrangement 10 are labelled 100 greater.

In this case, pivot 162 is in the form of a pin secured to and projecting from the shuttle 134 (both towards the viewer and away from the viewer). Lever 164 includes an end 184 which is forked, having fork tines 185 and 186, between which part of pin 162 sits.

The part of pin 162 which projects away from the viewer when viewing Figure 10 engages a slot 187 in the latch chassis 166.

When in the unlocked condition, the pin 162 is guided by the slot 187 as the shuttle translates generally leftwardly from the position shown in Figure 8 to the position shown in Figure 9.

When the latch is in a locked position, the fork times 185 and 186 hold the pin 162 stationary and hence the pivot axis 163 is held in the position shown in Figures 8, 10 and 11 thereby ensuring that the shuttle rotates about that axis and does not open the latch.

Figure 12 to 15 show a third embodiment, a latch arrangement 210 in which components which fulfil the same function as those of latch arrangement 10 and labelled 200 greater.

In this case, pivot 262 is in the form of a pin secured to the latch chassis 266. The shuttle includes an elongate slot 287 and an upstanding pin 288. A comparison between Figures 12, 14 and 15 shown that, when in the locked position the shuttle rotates about axis 263. End 289 of lever 264 bears against upstanding pin 288 and prevents it moving to the left, and hence prevents the shuttle moving to the left as shown in Figures 14 and 15. In the unlocked position, the lever 264 is free to rotate about pivot 265 and hence allow upstanding pin 288 and the shuttle 234 to move to the left as shown in Figure 13 thereby unlatching the latch.

With reference to Figures 16 to 19, there is shown a fourth embodiment of a latch arrangement 310 is which components that fulfil the same function as those of latch arrangement 10 are labelled 300 greater.

A comparison between Figure 4 and 16 shows that the post 75 has been deleted and has been replaced with a link 390. Link 390 includes an elongate slot 391 and is pivotably mounted to chassis 366 about pivot 392. A shuttle 334 includes an updating post 393. In the unlocked condition, the link 390 acts to guide the second arm 348 of the shuttle. In the locked condition, lever 364 is prevented from moving and hence the shuttle rotates about axis 363.

As can be seen, anticlockwise rotation of the shuttle is allowed for by the elongate slot 391, in other words upstanding post 393 moves along the elongate slot 391 towards pivot 392 in the locked condition (see Figures 18 and 19).

In this case, the spring 378 has been transferred to a different location. The coils 379 are positioned around post 376 which is concentric with pivot 365. Arm 380 bears upon an extension of pivot 392. Arm 381 bears upon upstanding post 393.

With reference to Figures 20 to 22, those show a fifth embodiment of a latch arrangement 410, in which components that fulfil the same function as those of latch arrangement 10 are labelled 400 greater.

Link 490, pivot 492 and upstanding post 493 are identical to those shown in Figure 16. Pin 54 of Figure 4 has been replaced by a flange 454 in Figure 21. Shuttle tooth 59 of Figure 4 has been deleted. Helical spring 478 has been positioned similarly to helical spring 378, namely around post 476 which is concentric with pivot 465. Whereas lever 64 was a straight lever, lever 464 has arms positioned approximately at 90 degrees to each. The release lever element 438 is pivotally mounted about post 477. The inside door handle 426 and outside door handle 428 are connected by a part of the transmission path to arm 495 of the release lever element 438.

For convenience certain components (such as the rotating claw, pawl, latch chassis, door, inside handle and outside handle, Electronic Control Unit (ECU)) have only been shown on certain views, and then only schematically.

As previously mentioned, a latch arrangement can have various security statuses. In the present invention the security status of the latch is controlled by an ECU 11 (only shown in figure 4). The ECU controls whether or not a current passes through electromagnet 72. It is also capable of sending a pulse of current through electromagnet 72 so as to swing the toggle 73 from the position shown in figure 4 to the position shown in figure 7. A reverse current pulse through electromagnet 72 will swing the toggle from the position shown in figure 7 to the position shown in figure 4. An operator can input the security status of a particular door to the ECU, and/or it can be predetermined by vehicle operating parameters. For example an operator can determine whether or not child safety should be turned on or off in respect of rear doors of a vehicle. Alternatively a vehicle manufacturer may predetermine that above a certain vehicle speed (such is 5 mph) all doors will become superlocked. When a door opening signal is received by the ECU, for example via an electrical switch sensing movement of either an inside door handle or an outside door handle, the ECU will determine the current security status of the appropriate latch and either allow or prevent opening. Thus, for example, where the security status of a latch has been set at locked then either the electromagnet will be activated or the toggle will be in the figure 7 position. Operation of an outside door handle will send a signal to the ECU and, because the door is locked, current will continue to pass through the electromagnet and/or the toggle will remain in the figure 7 position. However, if an inside door handle is operated then a signal will be sent from the inside door handle to the ECU which will then determine that releasing of the latch should occur whereby either the current flowing through the electromagnet 72 will be cut, or alternatively a pulse of current will be fed through the electromagnet so as to move the toggle from the figure 7 position to the figure 4 position, following which continued movement of the inside door handle will release the latch as described above. As will be appreciated, this mode of operation of utilising an ECU is applicable to all the above described embodiments.

The transmission path can take many forms. The outside door handle may typically pivot about a horizontal axis and be connected to the release lever element by a rod. The inside door handle 26 may typically pivot about a vertical axis and be connected to the release lever element by a cable. The pawl lifter may typically be rotationally fast with the pawl.

However, the first part of the transmission path could take any form of coupling, as could the second part of the transmission path. Furthermore, the shuttle could take any appropriate form.

In an alternative arrangement the present invention can be used with a "hybrid latch" i.e. a latch which in normal use will be released by an electrical actuator connected directly to the retaining means (such as the rotating pawl) and which is controlled by the ECU, but which in the event of power failure reverts to a mechanical release.

In this system when the vehicle is in use the mechanical release is prevented by energising the electromagnet and release can only occur when either operation of the outside handle or the inside handle is detected by sensors or switches which feed a signal to the ECU. The ECU instructs the electrical actuator to operate or not depending upon the lock status of the vehicle. If power fails, for instance in the event of a crash, the electrical release may not operate, but the electromagnet will no longer be energised and so the mechanical release will automatically become operable. The toggle will be used to prevent mechanical release when the vehicle is parked. The toggle may be connected to a key cylinder to allow mechanical release if the battery becomes flat whilst the vehicle is parked.

Claims

CLAIMS1. A latch arrangement including a latch bolt having a closed position and an open position, a retaining means having a retaining position for holding the latch bolt in the closed position and having a released position for allowing the latch bolt to move to the open position, a manually actuable element, and a transmission path operably connecting the manually actuable element to the retaining means, the transmission path having a first part, a shuttle, and a second part, the shuttle having a first shuttle abutment and a second shuttle abutment, the first part having a first transmission path abutment, the first part operably connecting the manually actuable element to the first transmission path abutment, the second part having a second transmission path abutment, a second part operably connecting the second transmission path abutment to the retaining means, the shuttle selectively operably connecting the manually actuable element to the retaining means by the first shuttle abutment engaging the first transmission path abutment and the second shuttle abutment engaging the second transmission path abutment, the latch arrangement having a rest position in which:-the shuttle is in a shuttle rest position, the first transmission path abutment is in a first transmission path abutment rest position, the second transmission path abutment is in a second transmission path abutment rest position, and the second transmission path abutment is proximate the second shuttle abutment, the latch arrangement having a first actuated position in which:-the shuttle is in a shuttle first actuated position, the first transmission path abutment is in a first transmission path abutment actuated position, the second transmission path abutment is in a second transmission path abutment actuated position, the first shuttle abutment is engaged with the first transmission path abutment, the second shuttle abutment is engaged with the second transmission path abutment, the latch arrangement having a second actuated position in which:-the shuttle is in a shuttle second actuated position, the first transmission path abutment is in said first transmission path abutment actuated position, the second transmission path abutment is in said second transmission path rest position, the first shuttle abutment is engaged with the first transmission path abutment, and the second shuttle abutment is remote from the second transmission path abutment, the latch arrangement having an unlocked condition in which operation of the manually operable element moves the latch arrangement from the rest position to the first actuated position to move the retaining means from the retaining position to the released position, the latch arrangement having a locked condition in which operation of the manually operable element moves the latch arrangement from the rest position to the second actuated position.
2. A latch arrangement as defined in claim 1 in which the shuttle is selectively pivotable about a first axis in a first direction from the shuttle rest position to the shuttle second actuated position.
3. A latch arrangement as defined in claim 2 in which a holding means selectively prevents translation of the shuttle relative to the first axis when the latch arrangement is in the locked condition.
4. A latch arrangement as defined in claim 3 in which the holding means is a lever pivotable about a second axis.
5. A latch arrangement as defined in claim 4 in which the lever includes an arm and the latch further includes an electro-magnet for holding said arm in an arm rest position when the latch arrangement is in the locked condition.
6. A latch arrangement as defined in claim 5 in which the electro-magnet is operable to move a magnetic toggle from a first toggle position where it allows movement of the arm to a second toggle position where it prevents movement of the arm.
7. A latch arrangement as defined in any one of claims 3 to 6 in which with the latch arrangement in said locked condition, operation of the manually operable element causes the first transmission path abutment to apply a force to the first shuttle abutment so as to rotate the shuttle about said first axis in said first direction.
8. A latch arrangement as defined in any preceding claim in which operation of the manually operable element when the latch arrangement is in the unlocked condition causes the second shuttle abutment to move generally linearly as the latch arrangement moves from the rest position to the first actuated position.
9. A latch arrangement as defined in any of claims 1 to 7 in which operation of the manually operable element when the latch arrangement is in the unlocked condition causes the second shuttle abutment to move in a path substantially similar to a path of movement of the second transmission path abutment.
10. A latch arrangement as defined in claim 1 in which the second transmission path abutment faces the second shuttle abutment when the latch arrangement is in the rest position and initial operation of the manually operable element when the latch arrangement is in the locked condition causes the second shuttle abutment to rotate away from the second transmission path abutment.
11. A latch arrangement including a latch bolt having a closed position and an open position, a retaining means having a retaining position for holding the latch bolt in the closed position and having a released position for allowing the latch bolt to move to the open position, a manually actuable element, and a transmission path operably connecting the manually actuable element to the retaining means, the transmission path having a first part, a shuttle, and a second part, the shuttle having a first shuttle abutment and a second shuttle abutment, the first part having a first transmission path abutment, the first part operably connecting the manually actuable element to the first transmission path abutment, the second part having a second transmission path abutment, a second part operably connecting the second transmission path abutment to the retaining means, the shuttle selectively operably connecting the manually actuable element to the retaining means by the first shuttle abutment engaging the first transmission path abutment and the second shuttle abutment engaging the second transmission path abutment, the latch arrangement having a rest position in which:-the shuttle is in a shuttle rest position, the first transmission path abutment is in a first transmission path abutment rest position, the second transmission path abutment is in a second transmission path abutment rest position, and the second transmission path abutment faces the second shuttle abutment, the latch arrangement having a first actuated position in which:-the shuttle is in a shuttle first actuated position, the first transmission path abutment is in a first transmission path abutment actuated position, the second transmission path abutment is in a second transmission path abutment actuated position, the first shuttle abutment is engaged with the first transmission path abutment, the second shuttle abutment is engaged with the second transmission path abutment, the latch arrangement having a second actuated position in which:-the shuttle is in a shuttle second actuated position, the first transmission path abutment is in said first transmission path abutment actuated position, the second transmission path abutment is in said second transmission path rest position, the first shuttle abutment is engaged with the first transmission path abutment, and the second shuttle abutment has been rotated away from the second transmission path abutment, the latch arrangement having an unlocked condition in which operation of the manually operable element moves the latch arrangement from the rest position to the first actuated position to move the retaining means from the retaining position to the released position, the latch arrangement having a locked condition in which operation of the manually operable element moves the latch arrangement from the rest position to the second actuated position.