Patent Description:
As shown in the <CIT>, a slide rail assembly including a first rail, a second rail, a third rail, a locking member and an operation member is disclosed. The second rail is capable of moving relative to the first rail from a first position to a second position. The third rail is capable of moving relative to the second rail. The locking member is mounted to the second rail for locking a portion of the first rail when the second rail is at the second position, such that the second rail is incapable of being moved relative to the first rail from the second position to the first position. A user can apply a force to the operation member to allow the operation member to displace relative to the second rail from a first predetermined position to a second predetermined position, such that the locking member is released from locking the portion of the first rail.

As shown in the <CIT>, a slide rail assembly including a first rail, a second rail, a blocking member, a positioning member and an operation member is disclosed. The blocking member is attached to the first rail. The positioning member is arranged at the second rail. The operation member is movably connected to the first rail. When the second rail is displaced relative to the first rail to an extending position, the second rail is prevented from retracting from the extending position along a retracting direction through the positioning member being blocked by the blocking member. The operation member is capable of being displaced from an initial position to a predetermined position through a force applied by a user. During the process that the operation member is displaced to the predetermined position, the operation member drives the blocking member of the first rail, such that the blocking member is in an unblocking state which is incapable of blocking the positioning member any longer, and the second rail is allowed to retract from the extending position along the retracting direction.

Besides, <CIT> discloses a slide rail assembly including a first rail, a second rail, a third rail and a switch member. The second rail is movably mounted between the first rail and the third rail. The switch member can be switched between a first state and a second state. When the switch member is at the second state, the second rail can be driven to a predetermined position toward a retracted direction by the third rail. When the third rail is moved toward an extended direction relative to the second rail being at the predetermined position, the third rail can move the switch member to the first state from the second state.

However, depending on different market demands, sometimes it is not desirable to use the methods of the above two patents for releasing the mutual blocking relationship between two slide rails. Therefore, development of a different product to satisfy various market demands becomes an issue that cannot be ignored.

This in mind, the present invention aims at providing a slide rail assembly.

This is achieved by a slide rail assembly according to claim <NUM>. The dependent claims pertain to corresponding further developments and improvements.

As will be seen more clearly from the detailed description following below, the claimed slide rail assembly includes a first rail, a second rail and an operation member. The first rail includes a positioning member and a blocking member. The second rail is capable of displacing relative to the first rail. The second rail includes a predetermined feature. When the second rail is displaced relative to the first rail from a first extending position to a second extending position along a retracting direction, the second rail is engaged with the positioning member through the predetermined feature so as to prevent the second rail from leaving the second extending position. The positioning member is driven through the operation member being operably moved from a second operation position to a first operation position, such that the predetermined feature is no longer engaged with the positioning member so as to allow the second rail to leave the second extending position. When the second rail is at the first extending position relative to the first rail, the blocking member is for blocking the second rail so as to prevent the second rail from displacing from the first extending position along the retracting direction. The blocking member is driven through the operation member being operably moved from the first operation position to the second operation position, such that the blocking member is incapable of blocking the second rail so as to allow the second rail to displace from the first extending position along the retracting direction. Each of the blocking member and positioning member includes an elastic material. Each of the blocking member and positioning member is an elastic sheet structure, and protrudes from a longitudinal wall of the first rail and faces toward the second rail.

As shown in <FIG>, according to the present invention, a slide rail assembly includes a first rail <NUM> and a second rail <NUM>. Preferably, the slide rail assembly can further include a third rail <NUM>. The second rail <NUM> is movably mounted between the first rail <NUM> and the third rail <NUM>. The first rail <NUM> can be mounted to a rack (a first post 25a and a second post 25b thereof). The third rail <NUM> can be configured to carry a carried object <NUM>. The first rail <NUM> (such as an outer rail), the second rail <NUM> (such as a middle rail) and the third rail <NUM> (such as an inner rail) are capable of longitudinally displacing relative to each other. The slide rail assembly is capable of in a fully extending state. Moreover, in the embodiment, the X-axis direction is a longitudinal direction (or a length direction or a displacement direction of a slide rail), the Y-axis direction is a transverse direction (or a lateral direction of the slide rail), and the Z-axis direction is a vertical direction (or a height direction of the slide rail). Specifically, the X-axis direction can be a longitudinal direction of the first rail <NUM>, and the Z-axis direction can be a height direction of the first rail <NUM>. Each of the first rail <NUM>, the second rail <NUM> and the third rail <NUM> is a slide rail.

As shown in <FIG>, the first rail <NUM> includes a first wall 28a, a second wall 28b and a longitudinal wall <NUM> connected between the first wall 28a and the second wall 28b of the first rail <NUM>. The first wall 28a, the second wall 28b and the longitudinal wall <NUM> of the first rail <NUM> together define a first passage <NUM>. The first passage <NUM> is for accommodating the second rail <NUM>. The first rail <NUM> includes a blocking member <NUM> and a positioning member <NUM>. Both of the blocking member <NUM> and the positioning member <NUM> includes an elastic material. Herein, both of the blocking member <NUM> and the positioning member <NUM> are elastic components (such as elastic seats or spring leafs).

Both of the blocking member <NUM> and the positioning member <NUM> are arranged at the longitudinal wall <NUM> of the first rail <NUM>.

Preferably, the blocking member <NUM> includes a first guiding portion 36a, a second guiding portion 36b and a supporting structure <NUM>. An end of the first guiding portion 36a and an end of the second guiding portion 36b are connected to the longitudinal wall <NUM> of the first rail <NUM>. Both of the first guiding portion 36a and the second guiding portion 36b may exemplarily be inclined surfaces or curved surfaces. The supporting structure <NUM> is located between the first guiding portion 36a and the second guiding portion 36b. The supporting structure <NUM> includes a blocking section <NUM>, a guiding section <NUM> and a longitudinal section <NUM>. Herein, the blocking section <NUM> is a blocking wall (or an upright wall), which is only exemplary, and the present invention is not limited thereto. The longitudinal section <NUM> is located between the blocking section <NUM> and the guiding section <NUM>. The guiding section <NUM> may exemplarily be an inclined surface or a curved surface. Herein, the blocking member <NUM> is an elastic sheet structure, and protrudes from the longitudinal wall <NUM> of the first rail <NUM> and faces toward the second rail <NUM>.

Preferably, the positioning member <NUM> includes a positioning portion <NUM>. Herein, the positioning portion <NUM> is an edge wall of a space (such as a hole), which is only exemplary, and the present invention is not limited thereto.

Preferably, the positioning member <NUM> further includes a first guiding feature <NUM> and a second guiding feature <NUM>, and the positioning portion <NUM> is located between the first guiding feature <NUM> and the second guiding feature <NUM>. Surfaces of the first guiding feature <NUM> and the second guiding feature <NUM> may exemplarily be inclined surfaces or curved surfaces. Herein, the positioning member <NUM> is an elastic sheet structure, and protrudes from the longitudinal wall <NUM> of the first rail <NUM> and faces toward the second rail <NUM>.

The blocking member <NUM> and the positioning member <NUM> are spaced by a distance along the X-axis direction, and the blocking member <NUM> is closer to a front end portion 22a of the first rail <NUM> than the positioning member <NUM>. The blocking member <NUM> and the positioning member <NUM> are spaced by a distance along the Z-axis direction.

The second rail <NUM> includes a first wall 52a, a second wall 52b and a longitudinal wall <NUM> connected between the first wall 52a and the second wall 52b of the second rail <NUM>. The first wall 52a, the second wall 52b and the longitudinal wall <NUM> of the second rail <NUM> together define a second passage <NUM>. The second passage <NUM> is for accommodating the third rail <NUM>. The third rail <NUM> includes a first wall 56a, a second wall 56b and a longitudinal wall <NUM> connected between the first wall 56a and the second wall 56b of the third rail <NUM>.

As shown in <FIG>, the second rail <NUM> has a first side L1 and a second side L2 opposite to the first side L1. The first side L1 is adjacent to the first rail <NUM>, and the second side L2 is adjacent to the third rail <NUM>. The second rail <NUM> includes a predetermined feature <NUM>. The predetermined feature <NUM> is configured to be cooperated with the positioning member <NUM> of the first rail <NUM>.

Preferably, the predetermined feature <NUM> is a protrusion arranged on the first side L1 of the longitudinal wall <NUM> of the second rail <NUM>. Herein, the predetermined feature <NUM> is a fixing pin connected to the longitudinal wall <NUM> of the second rail <NUM>, which is only exemplary, and the present disclosure in not limited thereto. For example, in other embodiment, the predetermined feature <NUM> can be a protruding portion integrally formed on the longitudinal wall <NUM> of the second rail <NUM>.

Preferably, the slide rail assembly further includes a working member <NUM> movably mounted to the second rail <NUM>. Herein, the working member <NUM> is pivotally connected to the second side L2 of the longitudinal wall <NUM> of the second rail <NUM> through a shaft member <NUM>, which is only exemplary, and the present disclosure in not limited thereto.

Preferably, the slide rail assembly further includes an elastic member <NUM> for providing an elastic force to the working member <NUM>.

Preferably, the longitudinal wall <NUM> of the second rail <NUM> has a through hole <NUM> communicating the first side L1 and the second side L2 of the second rail <NUM>. The working member <NUM> includes an extending portion <NUM> passing through a portion of the through hole <NUM> and protruding from the first side L1 of the second rail <NUM>. The extending portion <NUM> is configured to be cooperated with the blocking member <NUM> of the first rail <NUM>.

The slide rail assembly includes an operation member <NUM> for operating the blocking member <NUM> and the positioning member <NUM>. The operation member <NUM> is operably mounted to the second rail <NUM>. For example, the operation member <NUM> is movably mounted to the first side L1 of the longitudinal wall <NUM> of the second rail <NUM>. The operation member <NUM> includes an operation portion <NUM>, a driving portion <NUM> and a middle portion <NUM> connected between the operation portion <NUM> and the driving portion <NUM>.

Preferably, the operation portion <NUM> is adjacent to a front end portion 24a of the second rail <NUM>, and the driving portion <NUM> is adjacent to a rear end portion 24b of the second rail <NUM>.

Preferably, the second rail <NUM> and the operation member <NUM> have limiting features cooperated with each other, such that the operation member <NUM> is capable of longitudinally moving relative to the second rail <NUM> within a limited range. Herein, the second rail <NUM> and the operation member <NUM> are mounted to each other through at least one connecting member <NUM> passing through a portion of at least one elongated hole <NUM>, which is only exemplary, and the present disclosure in not limited thereto. That is, in the embodiment, the limiting features of the second rail <NUM> and the operation member <NUM> are the at least one connecting member <NUM> and the at least one elongated hole <NUM>.

Preferably, a first opening <NUM> is formed on the longitudinal wall <NUM> of the second rail <NUM>. A second opening <NUM> is formed on the operation member <NUM>. The second opening <NUM> is corresponding to the first opening <NUM> and a size of the second opening <NUM> is less than a size of the first opening <NUM>. The operation portion <NUM> is adjacent to the second opening <NUM>. The second opening <NUM> is adapted to be passed through by a finger of the user to allow the user to apply a force to the operation portion <NUM>, so as to drive the operation member <NUM> to move.

Preferably, the driving portion <NUM> of the operation member <NUM> includes a first driving section <NUM> and a second driving section <NUM> located at different heights. The first driving section <NUM> is for driving the blocking member <NUM> to move elastically. The second driving section <NUM> is for driving the positioning member <NUM> to move elastically.

The height of the first driving section <NUM> is corresponding to a height of the blocking member <NUM>. The height of the second driving section <NUM> is corresponding to a height of the positioning member <NUM>.

Preferably, the operation member <NUM> further includes a first space S1 and a second space S2 communicating two sides of the operation member <NUM>. The first driving section <NUM> is located behind the first space S1, and the second driving section <NUM> is located in front of the second space S2 (as shown in <FIG>).

Preferably, the extending portion <NUM> of the working member <NUM> extends to the first space S1 of the operation member <NUM>(as shown in <FIG>).

Preferably, at least one extending hole <NUM> is formed on the longitudinal wall <NUM> of the second rail <NUM> for communicating the first side L1 and the second side L2 of the second rail <NUM>. The operation member <NUM> further includes at least one auxiliary portion <NUM> passing through a portion of the at least one extending hole <NUM> and stretching out from the second side L2 of the second rail <NUM>.

As shown in <FIG> and <FIG>, the operation member <NUM> is capable of being operated to move between a first operation position P1 (as shown in <FIG>) and a second operation position P2 (as shown in <FIG>). For example, the user can apply a force F to the operation member <NUM> to allow the operation member <NUM> to move from the first operation position P1 to the second operation position P2. Alternatively, the operation member <NUM> can be applied with another force to allow the operation member <NUM> to return to the first operation position P1 from the second operation position P2.

Preferably, when the operation member <NUM> is located at the first operation position P1 relative to the second rail <NUM>, the predetermined feature <NUM> of the second rail <NUM> is located inside the second space S2, and the predetermined feature <NUM> of the second rail <NUM> and the second driving section <NUM> of the operation member <NUM> are close to each other (as shown in <FIG>). Alternatively, when the operation member <NUM> is located at the second operation position P2 relative to the second rail <NUM>, the predetermined feature <NUM> of the second rail <NUM> is located outside the second space S2, and the predetermined feature <NUM> of the second rail <NUM> and the second driving section <NUM> of the operation member <NUM> are far away from each other (as shown in <FIG>).

As shown in <FIG> and <FIG>, the slide rail assembly is applied to an environment with limited space. When the slide rail assembly is in the fully extending state, the second rail <NUM> is at a first extending position E1 relative to the first rail <NUM>, and the third rail <NUM> is at an opening position K (as shown in <FIG>) relative to the second rail <NUM>. When the second rail <NUM> is at the first extending position E1 relative to the first rail <NUM>, the slide rail assembly has a first length J1, and a first distance M1 is between the front end portion 26a of the third rail <NUM> and an object <NUM> (such as a door or an obstacle). Because the first distance M1 is too short, the third rail <NUM> is incapable of being detached from the second passage <NUM> of the second rail <NUM> along an opening direction D1.

When the second rail <NUM> is at the first extending position E1 relative to the first rail <NUM>, the blocking member <NUM> of the first rail <NUM> is in a blocking state Q1 capable of blocking the working member <NUM> (i.e., blocking the second rail <NUM>; as shown in <FIG>), so as to prevent the second rail <NUM> from displacing from the first extending position E1 along a retracting direction D2. Specifically, when the blocking member <NUM> is in the blocking state Q1, a top surface of the supporting structure <NUM> of the blocking member <NUM> and a surface of the longitudinal wall <NUM> of the first rail <NUM> together form a lateral height h1, and the blocking section <NUM> of the supporting structure <NUM> is capable of blocking the extending portion <NUM> of the working member <NUM> (as shown in <FIG>), so as to prevent the second rail <NUM> from displacing from the first extending position E1 along the retracting direction D2. Wherein, the operation member <NUM> is at the first operation position P1 relative to the second rail <NUM>, and the first driving section <NUM> of the operation member <NUM> is adjacent to the first guiding portion 36a of the blocking member <NUM>.

As shown in <FIG> and <FIG>, with the operation member <NUM> being operably moved from the first operation position P1 to the second operation position P2, the blocking member <NUM> is driven to leave the blocking state Q1 (For example, the blocking member <NUM> is in an unblocking state Q2), such that the blocking member <NUM> is incapable of blocking the working member <NUM> so as to allow the second rail <NUM> to displace from the first extending position E1 along the retracting direction D2. Specifically, when the operation member <NUM> is moved from the first operation position P1 to the second operation position P2, the operation member <NUM> pushes the first guiding portion 36a of the blocking member <NUM> through the first driving section <NUM>, such that the blocking member <NUM> is moved transversely (laterally) from the blocking state Q1 to the unblocking state Q2 (as shown in <FIG>). When the blocking member <NUM> is in the unblocking state Q2, the top surface of the supporting structure <NUM> of the blocking member <NUM> and the surface of the longitudinal wall <NUM> of the first rail <NUM> together form a height which is less that the lateral height h1, and the blocking section <NUM> of the supporting structure <NUM> is staggered from the extending portion <NUM> of the working member <NUM>, such that the blocking section <NUM> of the supporting structure <NUM> is incapable of blocking the extending portion <NUM> of the working member <NUM> (as shown in <FIG>) to allow the second rail <NUM> to displace from the first extending position E1 along the retracting direction D2. In other words, when the blocking member <NUM> is pushed toward the longitudinal wall <NUM> of the first rail <NUM> by the first driving section <NUM>, the blocking member <NUM> is changed from the blocking state Q1 to the unblocking state Q2. Moreover, when the operation member <NUM> is moved from the first operation position P1 to the second operation position P2, the operation member <NUM> is moved relative to the second rail <NUM> along the opening direction D1.

As shown in <FIG>, when the second rail <NUM> is displaced relative to the first rail <NUM> from the first extending position E1 to a second extending position E2 along the retracting direction D2 (as shown in <FIG> and <FIG>), the second rail <NUM> is engaged with the positioning member <NUM> through the predetermined feature <NUM> so as to prevent the second rail <NUM> from leaving the second extending position E2.

Specifically, during a process that the second rail <NUM> is displaced from the first extending position E1 to the second extending position E2 along the retracting direction D2, the second rail <NUM> contacts the first guiding feature <NUM> of the positioning member <NUM> through the predetermined feature <NUM> to drive the positioning member <NUM> to move from a first predetermined state W1 (as shown in <FIG>) to a second predetermined state W2, such that the positioning member <NUM> accumulates an elastic force F' (as shown in <FIG>). When the second rail <NUM> reaches the second extending position E2, the positioning member <NUM> returns from the second predetermined state W2 to the first predetermined state W1 (as shown in <FIG>) in response to the release of the elastic force F', such that the positioning member <NUM> is engaged with the predetermined feature <NUM> through the positioning portion <NUM> so as to prevent the second rail <NUM> from leaving the second extending position E2 (as shown in <FIG> and <FIG>). More specifically, when the positioning member <NUM> is in the first predetermined state W1, the positioning member <NUM> blocks a front end and a rear end of the predetermined feature <NUM> through a first wall 46a and a second wall 46b of the positioning portion <NUM>, respectively. As such, the second rail <NUM> is incapable of displacing from the second extending position E2 along the opening direction D1 or the retracting direction D2 (as shown in <FIG> and <FIG>). In other words, when the positioning member <NUM> is pushed toward the longitudinal wall <NUM> of the first rail <NUM> by the predetermined feature <NUM>, the positioning member <NUM> is changed from the first predetermined state W1 to the second predetermined state W2.

As shown in <FIG>, when the second rail <NUM> is at the second extending position E2 relative to the first rail <NUM>, the slide rail assembly has a second length J2 less than the first length J1, such that a second distance M2 which is larger than the first distance M1 (as shown in <FIG>) is between the front end portion 26a of the third rail <NUM> and the object <NUM>. Accordingly, it is favorable for the third rail <NUM> to be displaced along the opening direction D1 so as to be detached from the second passage <NUM> of the second rail <NUM> (as shown in <FIG>).

As shown in <FIG> and <FIG> to <FIG>, a contacting portion <NUM> (such as a protrusion, which is only exemplary) is arranged on the longitudinal wall <NUM> of the third rail <NUM> for being cooperated with the at least one auxiliary portion <NUM> of the operation member <NUM>.

When the second rail <NUM> is desired to be displaced relative to the first rail <NUM> from the second extending position E2 to a retracting position (such as a fully retracting position) along the retracting direction D2, the third rail <NUM> can be reinserted into the second passage <NUM> of the second rail <NUM> (as shown in <FIG>) from an outside of the second passage <NUM> of the second rail <NUM> (as shown in <FIG>). During the process, the third rail <NUM> is capable of contacting the auxiliary portion <NUM> of the operation member <NUM> through the contacting portion <NUM> to drive the operation member <NUM> to move relative to the second rail <NUM> from the second operation position P2 (as shown in <FIG> and <FIG>) to the first operation position P1 (as shown in <FIG>), such that the second driving section <NUM> of the operation member <NUM> contacts the first guiding feature <NUM> of the positioning member <NUM> to drive the positioning member <NUM>. That is, the positioning member <NUM> originally has a predetermined height h2 relative to the longitudinal wall <NUM> of the first rail <NUM> (as shown in <FIG>). The positioning member <NUM> is pushed by the second driving section <NUM> of the operation member <NUM>, such that the predetermined height h2 is decreased or the positioning member <NUM> is pushed to abut against the longitudinal wall <NUM> of the first rail <NUM>. As such, the positioning member <NUM> is no longer in the first predetermined state W1 (For example, the positioning member <NUM> is now in the second predetermined state W2 shown in <FIG>), and the positioning portion <NUM> of the positioning member <NUM> is no longer engaged with the predetermined feature <NUM>, which allows the second rail <NUM> to displace from the second extending position E2 along the retracting direction D2, or allows the second rail <NUM> to displace from the second extending position E2 along the opening direction D1. When the operation member <NUM> is moved from the second operation position P2 to the first operation position P1, the operation member <NUM> is moved relative to the second rail <NUM> along the retracting direction D2.

As shown in <FIG>, when the second rail <NUM> is at the second extending position E2 relative to the first rail <NUM>, the engagement relationship between the second rail <NUM> and the first rail <NUM> not only can be disengaged through the third rail <NUM> (as shown in <FIG>) but also can be disengaged by the user directly operating the operation member <NUM>. Specifically, through the operation member <NUM> being operably moved from the second operation position P2 to the first operation position P1, the positioning member <NUM> can be driven to leave the first predetermined state W1 (for example, the positioning member <NUM> is in the second predetermined state W2 as shown in <FIG>), such that the positioning portion <NUM> of the positioning member <NUM> is no longer engaged with the predetermined feature <NUM> and the positioning member <NUM> is incapable of blocking the second rail <NUM> so as to allow the second rail <NUM> to displace from the second extending position E2 along the retracting direction D2 or to allow the second rail <NUM> to displace from the second extending position E2 along the opening direction D1.

Moreover, during the process that the second rail <NUM> is displaced from the retracting position (such as the fully retracing position) to the first extending position E1 along the opening direction D1, the extending portion <NUM> of the working member <NUM> is capable of moving along the guiding section <NUM> and the longitudinal section <NUM> of blocking member <NUM> of the first rail <NUM> so as to be guided to the blocking section <NUM> (which can refer to <FIG>), such that the blocking section <NUM> of the blocking member <NUM> is capable of blocking the extending portion <NUM> of the working member <NUM> so as to prevent the second rail <NUM> to displace relative to the first rail <NUM> from the first extending position E1 along the retracting direction D2 (as shown in <FIG> and <FIG>), which is well known in the art and is not described in detail for the sake of conciseness.

To sum up, the slide rail assembly according to the present invention includes the following features.

First, the blocking relationship between the second rail <NUM> and the first rail <NUM> is capable of being released through the operating member <NUM> operating the blocking member <NUM> or the positioning member <NUM>, such that the second rail <NUM> is allowed to displace relative to the first rail <NUM> from an extending position (such as the first extending position E1 or the second extending position E2) along the retracting direction D2.

Claim 1:
A slide rail assembly, comprising:
a first rail (<NUM>) comprising a positioning member (<NUM>) and a blocking member (<NUM>);
a second rail (<NUM>) capable of displacing relative to the first rail (<NUM>), the second rail (<NUM>) comprising a predetermined feature (<NUM>); and
an operation member (<NUM>);
wherein when the second rail (<NUM>) is displaced relative to the first rail (<NUM>) from a first extending position (E1) to a second extending position (E2) along a retracting direction (D2), the second rail (<NUM>) is engaged with the positioning member (<NUM>) through the predetermined feature (<NUM>) so as to prevent the second rail (<NUM>) from leaving the second extending position (E2);
wherein the positioning member (<NUM>) is driven through the operation member (<NUM>) being operably moved from a second operation position (P2) to a first operation position (P1), such that the predetermined feature (<NUM>) is no longer engaged with the positioning member (<NUM>) so as to allow the second rail (<NUM>) to leave the second extending position (E2);
wherein when the second rail (<NUM>) is at the first extending position (E1) relative to the first rail (<NUM>), the blocking member (<NUM>) is for blocking the second rail (<NUM>) so as to prevent the second rail (<NUM>) from displacing from the first extending position (E1) along the retracting direction (D2);
wherein the blocking member (<NUM>) is driven through the operation member (<NUM>) being operably moved from the first operation position (P1) to the second operation position (P2), such that the blocking member (<NUM>) is incapable of blocking the second rail (<NUM>) so as to allow the second rail (<NUM>) to displace from the first extending position (E1) along the retracting direction (D2);
wherein each of the blocking member (<NUM>) and positioning member (<NUM>) comprises an elastic material;
characterized in that:
wherein each of the blocking member (<NUM>) and positioning member (<NUM>) is an elastic sheet structure, and protrudes from a longitudinal wall (<NUM>) of the first rail (<NUM>) and faces toward the second rail (<NUM>).