Patent Publication Number: US-11641940-B2

Title: Slide rail assembly

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a slide rail assembly, and more particular, to a slide rail assembly including a first rail and a second rail has a blocking mechanism for blocking the first rail relative to the second rail at an extending position, and an operating member for releasing the blocking mechanism. 
     2. Description of the Prior Art 
     U.S. Pat. No. 10,041,535 B2 discloses a slide rail assembly including a first rail, a second rail, a third rail, a locking member, and an operating member. The second rail is movable relative to the first rail between a first position and a second position. The third rail is movable relative to the second rail. The locking member is mounted on the second rail. When the second rail is positioned at the second position, the locking member is configured to lock a portion of the first rail, such that the second rail is not movable relative to the first rail from the second position toward the first position. The operating member is configured to be operated by a user to unlock the portion of the first rail from the locking member. When the operating member is moved from the first predetermined position to the second predetermined position through a force applied by the user, although the locking member can be used to unlock the part of the first rail, the disengaging action of the third rail from the second rail relies on a cooperation with a movement of the second rail that is pushed into the first rail. That is to say, such manner of operation is not suitable for single-person operation, and a trolley is required to disengage a chassis arranged with a third rail from the second rail in a confined space. 
     U.S. Pat. No. 9,681,749 B2 (case &#39;749) discloses a slide rail assembly that can be adapted to confined spaces. Case &#39;749 discloses that the operating member can be returned to an initial position from a predetermined position through a recovering elastic member. In other words, once the user blockings applying a force to the operating member, the operating member will be forced to return from the predetermined position to the initial position in response to the elastic force provided by the recovering elastic member. However, when two sets of slide rails are installed on one side of the chassis, there will be four slide rails on both sides of the chassis. Therefore, it is even more inadequate for single-handed operation. Therefore, the mechanism of the recovering elastic member forcing the operating member back to the initial position from the predetermined location through the elastic force provided by the recovering elastic member is unable to meet the requirements on the market in the industry. 
     SUMMARY OF THE INVENTION 
     The present invention provides a slide rail assembly, which is able to release a stopping mechanism through an operating member, such that a slide rail is able to be disengaged from an extending position relative to another slide rail. 
     According to one embodiment of the present invention, a slide rail assembly includes a first rail, a second rail, a blocking member, a positioning member, and an operating member. The first rail includes a blocking feature and a positioning feature. The second rail is movable relative to the first rail. The blocking member and the positioning member are movably mounted on the second rail, such that the blocking member and the positioning member are respectively at one of a first state and a second state relative to the second rail. The operating member is configured to operate one of the blocking member and the positioning member. When the second rail is positioned at a first extending position relative to the first rail, the blocking feature of the first rail blocks the blocking member at the first state, so as to prevent the second rail from being moved in a retracting direction from the first extending position. When the second rail is positioned at a second extending position relative to the first rail, the positioning member and the blocking member at the first state respectively corresponds to two portions of the positioning feature, so as to prevent the second rail from being moved in an extending direction or the retracting direction from the second extending position. When the second rail is positioned at the first extending position, the slide rail assembly has a first length. When the second rail is positioned at the second extending position, the slide rail assembly has a second length that is shorter than the first length. 
     According to another embodiment of the present invention, a slide rail assembly includes a first rail, a second rail, a blocking member, and a positioning member. The first rail includes a positioning feature. The second rail is movable relative to the first rail. The blocking member and the positioning member are movably mounted on the second rail, such that the blocking member and the positioning member are respectively positioned at one of a first state and a second state. When the second rail is moved from a retracted position to an extending position in an extending direction relative to the first rail, the second rail is prevented from being moved from the second extending position in the extending direction or a retracting direction relatively to the first rail, through the positioning member and the blocking member respectively corresponding to the two portions of the positioning feature of the first rail. 
     These and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment that is illustrated in the various figures and drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a schematic assembled perspective view of a slide rail assembly, including a first rail, a second rail, and a third rail, at an extending state according to a first embodiment of the present invention; 
         FIG.  2    is a schematic exploded perspective view of the slide rail assembly according to the first embodiment of the present invention; 
         FIG.  3    is an enlarged schematic view of part A in  FIG.  2   ; 
         FIG.  4    is a schematic perspective view of the second rail of the slide rail assembly and an operating member of the slide rail assembly at a first operating position according to the first embodiment of the present invention; 
         FIG.  5    is another schematic perspective view of the second rail of the slide rail assembly and the operating member of the slide rail assembly at the first operating position according to the first embodiment of the present invention; 
         FIG.  6    is a schematic perspective view of the second rail of the slide rail assembly and an operating member of the slide rail assembly at a second operating position according to the first embodiment of the present invention; 
         FIG.  7    is another schematic perspective view of the second rail of the slide rail assembly and the operating member of the slide rail assembly at the second operating position according to the first embodiment of the present invention; 
         FIG.  8    is a schematic perspective view illustrating the slide rail assembly being adapted to a rack and carrying a carrier according to the first embodiment of the present invention; 
         FIG.  9    is a schematic view illustrating the slide rail assembly at the extending state having a first length, and the operating member being positioned at the first operating position according to the first embodiment of the present invention; 
         FIG.  10    is a schematic view illustrating the slide rail assembly at the extending state, and the operating member being positioned at the second operating position according to the first embodiment of the present invention; 
         FIG.  11    is a schematic view illustrating the second rail of the slide rail assembly being able to move in a retracting direction relative to the first rail according to the first embodiment of the present invention; 
         FIG.  12    is a schematic view illustrating the second rail of the slide rail assembly being moved continuously in the retracting direction relative to the first rail according to the first embodiment of the present invention; 
         FIG.  13    is an enlarged schematic view of part A in  FIG.  12   ; 
         FIG.  14    is a schematic view illustrating the second rail of the slide rail assembly further being moved in the retracting direction relative to the first rail according to the first embodiment of the present invention; 
         FIG.  15    is a schematic view of the second rail of the slide rail assembly positioned at a second extending position relative to the first rail according to the first embodiment of the present invention; 
         FIG.  16    is a schematic view illustrating the slide rail assembly at another extending state having a second length according to the first embodiment of the present invention; 
         FIG.  17    is a schematic view illustrating the slide rail assembly at another extending state, and the third rail being able to be disengaged from the second rail according to the first embodiment of the present invention; 
         FIG.  18    is a schematic view illustrating the third rail of the slide rail assembly being moved in the retracting direction relative to the second rail according to the first embodiment of the present invention; 
         FIG.  19    is a schematic view illustrating the third rail of the slide rail assembly being moved continuously in the retracting direction relative to the second rail according to the first embodiment of the present invention; 
         FIG.  20    is a schematic view of the slide rail assembly at a fully retracted state according to the first embodiment of the present invention; 
         FIG.  21    is a schematic view illustrating the third rail of the slide rail assembly being moved in an extending direction relative to the second rail according to the first embodiment of the present invention; 
         FIG.  22    is a schematic view illustrating the third rail of the slide rail assembly being moved continuously in the extending direction relative to the second rail according to the first embodiment of the present invention; 
         FIG.  23    is a schematic view illustrating the third rail of the slide rail assembly further being moved in the extending direction relative to the second rail according to the first embodiment of the present invention; 
         FIG.  24    is a schematic view illustrating the second rail of the slide rail assembly being positioned at the second extending position relative to the first rail, and the operating member being positioned at the first operating position according to the first embodiment of the present invention; 
         FIG.  25    is a schematic view illustrating the second rail of the slide rail assembly being positioned at the second extending position relative to the first rail, and the operating member being positioned at the second operating position according to the first embodiment of the present invention; 
         FIG.  26    is a schematic partial view illustrating the second rail of slide rail assembly being positioned at the second extending position relative to the first rail, and the blocking member and the positioning member respectively blocking two portions of the positioning feature according to a second embodiment of the present invention; 
         FIG.  27    is a schematic partial view illustrating the second rail of slide rail assembly being positioned at the second extending position relative to the first rail, and the blocking member and the positioning member are respectively dislocated from blocking the two portions of the positioning feature through being motivated by the operating member according to the second embodiment of the present invention; 
         FIG.  28    is another schematic partial view illustrating the second rail of slide rail assembly being positioned at the second extending position relative to the first rail, and the blocking member and the positioning member respectively blocking two portions of the positioning feature according to the second embodiment of the present invention; 
         FIG.  29    is a schematic partial view illustrating the second rail of slide rail assembly being positioned at the second extending position relative to the first rail, and the blocking member and the positioning member are respectively dislocated from blocking the two portions of the positioning feature through being motivated by the third rail according to the second embodiment of the present invention; 
         FIG.  30    is a schematic view illustrating the slide rail assembly being at the extending state and the blocking feature of the first rail blocking the blocking member of the second rail according to a third embodiment of the present invention; 
         FIG.  31    is a schematic view illustrating the slide rail assembly being at the extending state and the blocking feature of the first rail not blocking the blocking member of the second rail according to the third embodiment of the present invention; 
         FIG.  32    is a schematic view illustrating the second rail and the third rail of the slide rail assembly being moved in the retracting direction relative to the first rail according to the third embodiment of the present invention; 
         FIG.  33    is a schematic view illustrating the second rail and the third rail of the slide rail assembly being moved continuously to the retracted position in the retracting direction relative to the first rail according to the third embodiment of the present invention; 
         FIG.  34    is a schematic view illustrating the second rail and the third rail of the slide rail assembly being moved in the extending direction relative to the first rail according to the third embodiment of the present invention; 
         FIG.  35    is an enlarged schematic view of part A in  FIG.  34   ; 
         FIG.  36    is a schematic view illustrating the second rail of the slide rail assembly being moved continuously in the extending direction relative to the first rail according to the third embodiment of the present invention; 
         FIG.  37    is a schematic view illustrating the second rail of the slide rail assembly being positioned at the second extending position relative to the first rail according to the third embodiment of the present invention; and 
         FIG.  38    is a schematic view illustrating the second rail of the slide rail assembly being positioned at the another extending state according to the third embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     As shown in  FIG.  1    and  FIG.  2   , a slide rail assembly  20  according to a first embodiment of the present invention includes a first rail  22  and a second rail  24 , and preferably, further includes a third rail  26 . The second rail  24  is movably mounted between the first rail  22  and the third rail  26 . The first rail  22  (e.g., an outer rail), the second rail  24  (e.g., a middle rail), and the third rail  26  (e.g., the inner rail) can move on a longitudinal direction relative to one another. When the slide rail assembly  20  is in a fully extended state, the second rail  24  is in a first extending position E 1  relative to the first rail  22 , and the third rail  26  is in an open position K relative to the second rail  24 . It is worth mentioning that, in this embodiment, the X-axis direction is the longitudinal direction (or a length direction of each of the slide rails or a moving direction of the slide rails), the Y-axis direction is the transverse direction (or a lateral direction of each of the slide rails), and the Z-axis direction is the vertical direction (or a height direction of each of the slide rails). 
     The first rail  22  includes a first wall  28   a , a second wall  28   b , and a longitudinal wall  30  connected between the first wall  28   a  and the second wall  28   b  of the first rail  22 . The first wall  28   a , the second wall  28   b  and the longitudinal wall  30  of the first rail  22  jointly define a first channel, and the first channel is used to accommodate the second rail  24 . The first rail  22  includes a blocking feature  32  (as shown in  FIG.  2   ). Preferably, the first rail  22  further includes a first released feature  34 , a positioning feature  36  and a second released feature  38 . The blocking feature  32 , the first released feature  34 , the positioning feature  36  and the second released feature  38  are arranged in sequence from front to back on the longitudinal wall  30  of the first rail  22 . 
     Preferably, the slide rail assembly  20  further includes an elastic seat  33  mounted on the first rail  22 , and the elastic seat  33  includes a first connecting portion  40   a , a second connecting portion  40   b  and a supporting structure  42  (as shown in  FIG.  2   ), the first connecting portion  40   a  and the second connecting portion  40   b  are both connected to the longitudinal wall  30  of the first rail  22 , and the supporting structure  42  is positioned between the first connecting portion  40   a  and the second connecting portion  40   b . The supporting structure  42  includes the blocking feature  32 , a longitudinal portion  25 , and a guiding portion  27 . In addition, the blocking feature  32  can be exemplified as a retaining wall (or a standing wall), but the present invention is not limited thereto. Furthermore, the longitudinal portion  25  is positioned between the blocking feature  32  and the guiding portion  27 , and the guiding portion  27  is, for example, an inclined surface or an arc surface. 
     Preferably, the first released feature  34  and the second released feature  38  have structural configurations that are substantially identical. For ease of illustration, only the first released feature  34  is described herein. For example, the first released feature  34  is a protrusion protruding laterally (or transversely) relatively to the longitudinal wall  30  of the first rail  22 , and a front portion and a back portion of the first released feature  34  respectively have a first guiding section  44   a  and a second guiding section  44   b . The first guiding section  44   a  and the second guiding section  44   b  are inclined surfaces (or curved surfaces), but the present invention is not limited thereto. 
     Preferably, the slide rail assembly  20  further includes a first auxiliary portion  46  and a second auxiliary portion  48 , and the positioning feature  36  is defined between the first auxiliary portion  46  and the second auxiliary portion  48 . The first auxiliary portion  46  and the second auxiliary portion  48  are symmetrical to and separate from each other for a distance. The first auxiliary portion  46  and the second auxiliary portion  48  have structural configurations that are substantially identical. For ease of illustration, only the first auxiliary portion  46  is described herein. For example, the first auxiliary portion  46  is a protrusion protruding laterally (or transversely) relatively to the longitudinal wall  30  of the first rail  22 . 
     Preferably, the first auxiliary portion  46  and the second auxiliary portion  48  respectively have a first guiding structure  50  and a second guiding structure  52 , and the first guiding structure  50  and the second guiding structure  52  are inclined surfaces (or curved surfaces), but the present invention is not limited thereto. 
     The second rail  24  includes a first wall  54   a , a second wall  54   b , and a longitudinal wall  56  connected between the first wall  54   a  and the second wall  54   b  of the second rail  24 . The first wall  54   a , the second wall  54   b , and the longitudinal wall  56  of the second rail  24  jointly define a second channel, and the second channel is used to accommodate the third rail  26 . The second rail  24  has a first side L 1  and a second side L 2  that are opposite to each other in position. The first side L 1  is adjacent to the first rail  22 , and the second side L 2  is adjacent to the third rail  26 . 
     The slide rail assembly  20  includes a blocking member  58  and an operating member  60 , and preferably, the slide rail assembly  20  further includes a positioning member  62  and a recovering elastic member  64 . The second rail  24 , the blocking member  58 , the operating member  60 , and the recovering elastic member  64  can form a slide rail kit. The blocking member  58  and the positioning member  62  are both movably mounted on the second rail  24 . In one of the implementations, the blocking member  58  and the positioning member  62  are exemplified as being pivotally connected to the second side L 2  of the longitudinal wall  56  of the second rail  24  through a first shaft  66  and a second shaft  68 , respectively, but the present invention is not limited thereto. 
     Preferably, the second rail  24  includes at least one hole communicating with the first side L 1  and the second side L 2  of the longitudinal wall  56  of the second rail  24 . In addition, the at least one hole is exemplified as a first hole H 1  and a second hole H 2  herein. Furthermore, the blocking member  58  includes a blocking portion  55  penetrating into the first hole H 1 , the blocking portion  55  faces the longitudinal wall  30  of the first rail  22 , and the blocking portion  55  is to be used in conjunction with the blocking feature  32  of the first rail  22 . On the other hand, the positioning member  62  includes a positioning portion  63  penetrating into the second hole H 2 , the positioning portion  63  faces the longitudinal wall  30  of the first rail  22 , and the positioning portion  63  is to be used in conjunction with the positioning feature  36  of the first rail  22 . In addition, the positioning portion  63  is exemplified as a column, but the present invention is not limited thereto. 
     Preferably, the slide rail assembly  20  further includes a predetermined object  69  connected to the longitudinal wall  56  of the second rail  24 , and the predetermined object  69  has a first elastic feature  70  and a second elastic feature  72 , so as to provide an elastic force to the blocking member  58  and the positioning member  62 , respectively. 
     Preferably, the second rail  24  and the positioning member  62  include limiting structures that are adapted to each other, such that the positioning member  62  can be moved relative to the second rail  24  within a limited range. In one of the implementations, the limiting structures are exemplified as the longitudinal wall  56  of the second rail  24  including a corresponding portion  74  (e.g., a convex body) penetrating a part of a limiting space  76  of the positioning member  62 , but the present invention is not limited thereto. 
     The operating member  60  is operatively mounted on the second rail  24 , and the operating member  60  is used to operate the blocking member  58  and the positioning member  62 , or to operate one of the blocking member  58  and the positioning member  62 . 
     Preferably, the operating member  60  is positioned on the first side L 1  of the longitudinal wall  56  of the second rail  24 , and the operating member  60  includes an operating portion  78 , a driving portion  80 , and an extension portion  82  connected between the operating portion  78  and the driving portion  80 . The operating portion  78  is positioned at a front end portion  24   a  adjacent to the second rail  24 ; on the other hand, the blocking member  58  and the positioning member  62  are positioned adjacent to a back end portion  24   b  of the second rail  24 . 
     Preferably, the second rail  24  further includes a third hole H 3 , through which the driving portion  80  of the operating member  60  can penetrate from the first side L 1  to the second side L 2  of the second rail  24  through the third hole H 3 , and the driving portion  80  is positioned adjacent to the blocking member  58 . 
     Preferably, the second rail  24  and the operating member  60  include limiting features that are adapted to each other, such that the operating member  60  can be moved longitudinally relative to the second rail  24  within a limited range. In one of the implementations, the extension portion  82  of the operating member  60  are exemplified to include at least one elongated hole  84 , and at least one connecting member  86  penetrates through a part of the at least one elongated hole  84 , such that the at least one connecting member  86  is connected to the longitudinal wall  56  of the second rail  24 , but the present invention is not limited thereto. 
     The recovering elastic member  64  is used to provide a recovering elastic force to the operating member  60 . In one of the implementations, the two ends of the recovering elastic member  64  are exemplified as being respectively connected to the operating member  60  and the second rail  24  (the longitudinal wall  56 ), but the present invention is not limited thereto. 
     Preferably, the operating member  60  includes an engaging feature  88  (as shown in  FIG.  3   ). The slide rail assembly  20  is exemplified as further including an elastic component  90  connected to the operating member  60 , the elastic component  90  includes a connecting section  92  and an elastic section  94 , the connecting section  92  is connected to the extension portion  82  of the operating member  60 , the elastic section  94  is connected to the connecting section  92 , and the elastic section  94  includes the engaging feature  88 . 
     Preferably, the engaging feature  88  is, for example, a hook, and the engaging feature  88  has a guiding surface  96 , such as an inclined surface or a curved surface (as shown in  FIG.  3   ). 
     Preferably, the elastic section  94  of the elastic component  90  further includes a release feature  98 , and the release feature  98  is, for example, a protrusion. A front portion and a back portion of the release feature  98  each have a first guiding feature  100   a  and a second guiding feature  100   b  which can each be, for example, an inclined surface or a curved surface (as shown in  FIG.  3   ). 
     As shown in  FIG.  4    and  FIG.  5   , both the blocking member  58  and the positioning member  62  can be in a first state S 1  relative to the second rail  24  (as shown in  FIG.  4   ). On the other hand, the operating member  60  can be positioned at a first operating position P 1  relative to the second rail  24  (as shown in  FIG.  4    and  FIG.  5   ). 
     Preferably, the blocking member  58  further includes a contact portion  102  and an actuation portion  104 , and the first shaft  66  is positioned between the contact portion  102  and the actuation portion  104 . In addition, the contact portion  102  corresponds to (or contacts) the driving portion  80  of the operating member  60  (as shown in  FIG.  4   ), the blocking portion  55  is adjacent to the actuation portion  104  (as shown in  FIG.  4   ), and the blocking portion  55  extends to the first side L 1  of the second rail  24  (as shown in  FIG.  5   ). The first elastic feature  70  provides an elastic force to the blocking member  58 , and the blocking member  58  is retained at the first state S 1  (as shown in  FIG.  4   ). 
     Preferably, the positioning member  62  includes a contact section  106  and an actuation section  108 , and the second shaft  68  is positioned between the contact section  106  and the actuation section  108 . In addition, the positioning portion  63  is adjacent to the contact section  106  (as shown in  FIG.  4   ), and the positioning portion  63  extends to the first side L 1  of the second rail  24  (as shown in  FIG.  5   ). The second elastic feature  72  provides an elastic force to the positioning member  62 , and the positioning member  62  is retained at the first state S 1  (as shown in  FIG.  4   ). 
     Preferably, the release feature  98  of the elastic section  94  of the elastic component  90  penetrates through a corresponding hole  110  of the extension portion  82  of the operating member  60  (as shown in  FIG.  5   ), and the release feature  98  is to be used in conjunction with the first released feature  34  (or the second released feature  38 ) of the first rail  22 . 
     Preferably, the longitudinal wall  56  of the second rail  24  has a first corresponding space M 1 , a second corresponding space M 2 , and a predetermined wall  112  positioned between the first corresponding space M 1  and the second corresponding space M 2 , and the predetermined wall  112  separates the first corresponding space M 1  from the second corresponding space M 2 . When the operating member  60  is positioned at the first operating position P 1  relative to the second rail  24 , the engaging feature  88  of the elastic component  90  corresponds to the first corresponding space M 1  (as shown in  FIG.  5   ), and the engaging feature  88  of the elastic component  90  is adjacent to a first wall portion  112   a  of the predetermined wall  112 . 
     As shown in  FIG.  6    and  FIG.  7   , the user can apply a force F to the operating member  60  (the operating portion  78 ), so that the operating member  60  can be moved relative to the second rail  24  from the first operating position P 1  to a second operating position P 2 ; during this process, the operating member  60  contacts the contact portion  102  of the blocking member  58  through the driving portion  80  to drive the blocking member  58  to be moved (e.g., pivotally rotate) from being at the first state S 1  to a second state S 2  (as shown in  FIG.  6   ). Preferably, the blocking member  58  contacts the positioning portion  63  of the positioning member  62  through the actuation portion  104  to drive the positioning member  62 , such that the positioning member  62  is moved (e.g., pivotally rotates) from being at the above-mentioned first state S 1  to the second state S 2  (as shown in  FIG.  6   ). 
     When the operating member  60  is positioned at the second operating position P 2 , the recovering elastic member  64  can accumulate the recovering elastic force F′ (as shown in  FIG.  7   ) back to the first operating position P 1 , and the engaging feature  88  of the elastic component  90  corresponds to the second corresponding space M 2 , and the operating member  60  is engaged with a predetermined portion of the second rail  24  through the engaging feature  88  (e.g., the engaging feature  88  is engaged with a second wall portion  112   b  of the predetermined wall  112  of the second rail  24 ), such that the operating member  60  is positioned at the second operating position P 2  (as shown in  FIG.  7   ). 
     Preferably, when the operating member  60  is moved from the first operating position P 1  (as shown in  FIG.  5   ) to the second operating position P 2  (as shown in  FIG.  7   ), the engaging feature  88  can be contacted with the first wall portion  112   a  (as shown in  FIG.  5   ) through the guiding surface  96 , which facilitates the engaging feature  88  to cross over the predetermined wall  112  until the engaging feature  88  corresponds to the second corresponding space M 2  (as shown in  FIG.  7   ), such that the engaging feature  88  can be engaged with the second wall portion  112   b  of the predetermined wall  112  of the second rail  24  (as shown in  FIG.  7   ). For example, in one of the implementations, the engaging feature  88  can be abutted against the first wall portion  112   a  and then moved underneath the predetermined wall  112  guided by the guiding surface  96 , such that the engaging feature  88  can be engaged with the second wall portion  112   b  once fully emerged from the predetermined wall  112 . Therefore, the engaging feature  88  can be efficiently moved from one side to another side (i.e., from the first wall portion  112   a  to the second wall portion  112   b ) of the predetermined wall  112 , and more firmly engaged with the second wall portion  112   b  without being dislocated or disengaged. 
     Preferably, when the operating member  60  is positioned at the second operating position P 2 , the operating member  60  is used to retain the blocking member  58  and the positioning member  62  at the second state S 2  (as shown in  FIG.  6   ). The operating member  60  contacts the positioning member  62  through the blocking member  58  at the second state S 2 , so that the positioning member  62  is also retained at the second state S 2  (as shown in  FIG.  6   ). 
     As shown in  FIG.  8   , a carrier  114  can be mounted on a frame  116  through the slide rail assembly  20 . The slide rail assembly  20  is in the fully extended state. In addition, the first rail  22  is mounted on (or fixed to) the rack  116  (the first rail  22  is not shown in  FIG.  8    due to the view angle), and the third rail  26  is used to carry the carrier  114 , such that the carrier  114  can be moved between the inside of the frame  116  and the outside of the frame  116  through the third rail  26 . 
     As shown in  FIG.  9   , the slide rail assembly  20  is at the fully extended state. The second rail  24  is positioned at the first extending position E 1  relative to the first rail  22 , and the third rail  26  is at the open position K relative to the second rail  24 . Preferably, at least one auxiliary slide device is movably arranged between every two of the slide rails to facilitate the smoothness of the relative movement of each of the two slide rails. For example, a first auxiliary slide device  118  is arranged between the first rail  22  and the second rail  24 , and a second auxiliary slide device  120  is arranged between the second rail  24  and the third rail  26 , and each of the auxiliary slide devices  118 ,  120  includes a plurality of balls B. It is worth mentioning that, when the second rail  24  is positioned at the first extending position E 1  relative to the first rail  22 , the slide rail assembly  20  has a first length J 1 , such that a first distance X 1  is between the front end  26   a  of the third rail  26  and an object  122  (e.g., a door or an obstacle). In addition, since the first distance X 1  is too narrow, the third rail  26  is unable to be moved in an extending direction D 1  and be disengaged from the second channel of the second rail  24 . When the second rail  24  is positioned at the first extending position E 1  relative to the first rail  22 , the blocking feature  32  can block the blocking portion  55  of the blocking member  58  in the first state S 1  to prevent the second rail  24  from being moved from the first extending position E 1  in a retracting direction D 2 . On the other hand, the positioning member  62  contacts the guiding portion  27  of the elastic seat  33  of the first rail  22  through the positioning portion  63 . In addition, the operating member  60  is in the first operating position P 1 , the recovering elastic member  64  is in a state of not accumulated with the recovering elastic force, and the engaging feature  88  of the elastic section  94  of the elastic component  90  is adjacent to the first wall portion  112   a  of the predetermined wall  112  (as shown in  FIG.  5   ). 
     As shown in  FIG.  10   , the user can move the operating member  60  from the first operating position P 1  to the second operating position P 2 , through applying the force F to the operating portion  78  of the operating member  60 , and the driving portion  80  can drive the operating member  60  to be moved from the first operating position P 1  to the second operating position P 2 , so that the blocking feature  32  is unable to block the blocking member  58  at the second state S 2 , so as to allow the second rail  24  to be moved from the first extending position E 1  in the retracting direction D 2  relative to the first rail  22 . On the other hand, the blocking member  58  motivates the positioning member  62 , such that the positioning member  62  is at the second state S 2 . When the blocking member  58  and the positioning member  62  are at the second state S 2 , the first elastic feature  70  and the second elastic feature  72  are respectively in a state of accumulating elasticity (as shown in  FIG.  6   ). In addition, when the operating member  60  is positioned at the second operating position P 2 , the recovering elastic member  64  is in a state of being accumulated with the recovering elastic force F′, and the engaging feature  88  of the elastic section  94  of the elastic component  90  is engaged with the second wall portion  112   b  of the predetermined wall  112  of the second rail  24 , and is used to retain the operating member  60  at the second operating position P 2  (as shown in  FIG.  7   ). 
     As shown in  FIG.  11   , when the second rail  24  is moved from the first extending position E 1  in the retracting direction D 2  relative to the first rail  22 , (the second guiding feature  100   b  of) the release feature  98  of the elastic component  90  of the operating member  60  and (the first guiding section  44   a  of) the first released feature  34  of the first rail  22  are in contact with each other, such that the elastic section  94  of the elastic component  90  can be driven to disengage the engaging feature  88  from the second wall portion  112   b  of the predetermined wall  112  of the second rail  24 . 
     As shown in  FIG.  12    and  FIG.  13   , the second rail  24  can be moved continuously in the retracting direction D 2  relative to the first rail  22 . Once the engaging feature  88  is no longer engaged with the second wall portion  112   b  of the predetermined wall  112  of the second rail  24 , the recovering elastic member  64  releases the recovering elastic force F′ to the operating member  60 , so that the operating member  60  can return from the second operating position P 2  to the first operating position P 1 , and that the engaging feature  88  returns to the position of the first wall portion  112   a  of the predetermined wall  112  adjacent to the second rail  24  (as shown in  FIG.  13   , which can be read in conjunction with  FIG.  5   ), and the blocking member  58  and the positioning member  62  respectively respond to the elastic force provided by the first elastic feature  70  and the second elastic feature  72 , and return from the second state S 2  to the first state S 1 . 
     As shown in  FIG.  14    and  FIG.  15   , when the second rail  24  is further moved in the retracting direction D 2  to a second extending position E 2  relative to the first rail  22 , the positioning member  62  is pivotally rotated for a certain angle through being guided by the positioning portion  63  along the first guiding structure  50  (e.g; an inclined surface or an arc surface) of the first auxiliary portion  46 , so that the second elastic feature  72  is in a state of accumulated with elasticity (as shown in  FIG.  14   ); until the second rail  24  positioned at the second extending position E 2  (as shown in  FIG.  16   ), the positioning member  62  responds to the elastic force of the second elastic feature  72  to be at the first state S 1 , so that the positioning portion  63  of the positioning member  62  is engaged with the positioning feature  36  of the first rail  22 . For example, the positioning portion  63  of the positioning member  62  is arranged between the first auxiliary portion  46  and the second auxiliary portion  48  to prevent the second rail  24  from being moved relative to the first rail  22  from the second extending position E 2  in the retracting direction D 2  or the extending direction D 1 . 
     As shown in  FIG.  16    and  FIG.  17   , when the second rail  24  is at the second extending position E 2  relative to the first rail  22 , the slide rail assembly  20  has a second length J 2  smaller than the aforementioned first length J 1 , so that a second distance X 2 , defined between the front end portion  26   a  of the third rail  26  and the object  122 , is greater than the above-mentioned first distance X 1 . Therefore, it is advantageous for the third rail  26  to be moved in the extending direction D 1  and be disengaged from the second channel of the second rail  24  (as shown in  FIG.  17   ). 
     As shown in  FIG.  18    to  FIG.  20   , the third rail  26  includes a first wall  29   a , a second wall  29   b , and a longitudinal wall  31  connected between the first wall  29   a  and the second wall  29   b  of the third rail  26 . Furthermore, when the second rail  24  is to be moved from the second extending position E 2  in the retracting direction D 2  to a retracted position R (e.g., a fully retracted position) relative to the first rail  22 , the second rail  24  can be moved to a retracted position R (e.g., a fully retracted position). The third rail  26  is moved from the open position K in the retracting direction D 2  until (the back end  26   b  of) the third rail  26  contacts an auxiliary section  124  of the blocking member  58  (the auxiliary section  124  is connected to the actuation portion  104  of the blocking member  58 , as shown in  FIG.  18   ), such that the blocking member  58  is no longer at the first state S 1 , and the positioning member  62  motivated by the blocking member  58  is also no longer at the first state S 1 , and that the positioning portion  63  of the positioning member  62  is released from the positioning feature  36  (as shown in  FIG.  19   ) to allow the second rail  24  to be moved from the second extending position E 2  in the retracting direction D 2  relative to the first rail  22 , until the slide rail assembly  20  is at a fully retracted state (as shown in  FIG.  20   ). At this time, the second rail  24  is in the retracted position R relative to the first rail  22 , and the third rail  26  is in a predetermined retracted position relative to the second rail  24 . It is worth mentioning that, as shown in  FIG.  19    and  FIG.  20   , the second wall  29   b  and the first wall  29   a  of the third rail  26  respectively support the blocking member  58  and the positioning member  62  to retain the blocking member  58  and the positioning member  62  to not be at the first state S 1  (i.e., the blocking member  58  and the positioning member  62  are no longer at the first state S 1 ), and the first elastic feature  70  and the second elastic feature  72  are in the state of accumulated with elasticity. It is worth mentioning that, since the first wall  29   a  of the third rail  26  is on a movement path (a pivotally rotation path) of the positioning member  62 , the positioning member  62  can be retained in a state other than the first state S 1 . 
     As shown in  FIG.  20    to  FIG.  23   , the third rail  26  includes a synchronization feature  126  (for example, a hole wall, but the present invention is not limited thereto) mounted on the second wall  29   b  of the third rail  26 . Furthermore, when the third rail  26  is moved relative to the second rail  24  from the retracted position (as shown in  FIG.  20   ) to the extending direction D 1  for a predetermined stroke, the synchronization feature  126  of the third rail  26  corresponds to the auxiliary section  124  of the blocking member  58 , such that the blocking member  58  responds to the elastic force provided by the first elastic feature  70  and is engaged with the synchronization feature  126  of the third rail  26  through the auxiliary section  124  to allow the second rail  24  to be moved simultaneously with the third rail  26  the extending direction D 1  (as shown in  FIG.  21   ). When the blocking member  58  is moved in the extending direction D 1  for the predetermined stroke, the blocking portion  55  of the blocking member  58  is moved in the extending direction D 1  along the guiding portion  27  of the elastic seat  33  of the first rail  22  and reaches the longitudinal portion  25  of the elastic seat  33 , such that the blocking member  58  is rotated for an angle, and that the auxiliary section  124  of the blocking member  58  is disengaged from the synchronization feature  126  of the third rail  26 , thereby dismissing the simultaneously movement between the second rail  24  and the third rail  26  (as shown in  FIG.  22   ). When the third rail  26  is moved in the extending direction D 1  relative to the second rail  24 , so that the second wall  29   b  and the first wall  29   a  of the third rail  26  no longer support the blocking member  58  and the positioning member  62 , respectively, and the second rail  24  is moved relative to the first rail  22  to the first extending position E 1 , the blocking member  58  is at the first state S 1 , and the blocking portion  55  of the blocking member  58  is blocked by the blocking feature  32  of the first rail  22  to prevent the second rail  24  from being moved from the first extending position E 1  in the retracting direction D 2  (as shown in  FIG.  23   , which can be read in conjunction with  FIG.  9   ). 
     As shown in  FIG.  24    and  FIG.  25   , when the second rail  24  is in the second extending position E 2  relative to the first rail  22 , in addition to the above-mentioned manner of the third rail  26  relieving an engaging relation between (i.e., the simultaneous movement of) the second rail  24  and the first rail  22  (for example, as shown in  FIG.  18    and  FIG.  19   ), in one of the implementations, the user can also directly relieve the engaging relation between the second rail  24  and the first rail  22  through the operating member  60 . Furthermore, when the second rail  24  is at the second extending position E 2  relative to the first rail  22 , the user can apply the force F to the operating member  60 , so as to move the operating member  60  from the first operating position P 1  to the second operating position P 2 , such that the blocking member  58  can be driven by the driving portion  80  from being at the first state S 1  to the second state S 2 , and the blocking member  58  can drive the positioning member  62  from being at the first state S 1  to the second state S 2 , and the positioning portion  63  of the positioning member  62  is disengaged from the positioning feature  36  of the first rail  22 , which allow the second rail  24  to be moved from the second extending position E 2  in the retracting direction D 2  (or the extending direction D 1 ) relative to the first rail  22 . When the operating member  60  is positioned at the second operating position P 2 , the operating member  60  is engaged with the predetermined portion of the second rail  24  through the engaging feature  88  to retain the operating member  60  at the second operating position P 2  (as shown in  FIG.  7   ). 
     When the second rail  24  is being moved from the second extending position E 2  in the retracting direction D 2  to the retracted position R, the second released feature  38  of the first rail  22  can drive the elastic component  90  to disengage the engaging feature  88  from the predetermined portion of the second rail  24 , so that the operating member  60  can return to the first operating position P 1  from the second operating position P 2  through the recovering elastic force F′ of the recovering elastic member  64 . In addition, the technical principle described herein is substantially identical to that of  FIG.  11   , and will not be reiterated. 
     One of the beneficial effects of the slide rail assembly  20  and the slide rail kit of the present invention is that the operating member  60  can be retained at the second operating position P 2  through the engaging feature  88  being engage with the predetermined portion of the second rail  24 , and once the engaging feature  88  is no longer engaged with the predetermined portion of the second rail  24 , the recovering elastic force provided by the recovering elastic member  64  allows the operating member  60  to return from the second operating position P 2  to the first operating position P 1 . 
     Referring to  FIG.  26   , a slide rail assembly  200  according to the second embodiment of the present invention is provided. The essential difference between the slide rail assembly  200  of the second embodiment and the slide rail assembly  20  of the first embodiment described above is that the positioning feature  204  of the first rail  202  can be a protrusion that protrudes laterally (horizontally) relative to the longitudinal wall  205  of the first rail  202 , and the positioning portion  208  of the positioning member  206  may be an extended arm. 
     Furthermore, the longitudinal wall  212  of the second rail  210  has a first hole H 1 ′ and a second hole H 2 ′ that are communicated between the first side and the second side of the longitudinal wall  212  of the second rail  210  (as described in the first embodiment, and will not be reiterated herein). The blocking portion  216  of the blocking member  214  penetrates through the first hole H 1 ′, and the positioning portion  208  of the positioning member  206  penetrates through the second hole H 2 ′. 
     When the second rail  210  is positioned at the second extending position E 2  relative to the first rail  202 , the second rail  210  provides a blocking effect or an engaging effect to prevent the second rail  210  from being moved from the second extending position E 2  relative to the first rail  202  in the extending direction D 1  or the retracting direction D 2  through the positioning portion  208  of the positioning member  206  at the first state S 1  and the blocking portion  216  of the blocking member  214  at the first state S 1  corresponding to the two portions (e.g., the back portion  204   b  and the front portion  204   a ) of the positioning feature  204 . 
     As shown in  FIG.  26    and  FIG.  27   , when the second rail  210  is positioned at the second extending position E 2  relative to the first rail  202 , the user can release the blocking or engaging relation between the second rail  210  and the first rail  202  through the operating member  218 . Furthermore, the user can apply the force F to move the operating member  218  from the first operating position P 1  (as shown in  FIG.  26   ) to the second operating position P 2  (as shown in  FIG.  27   ), and the driving portion  220  can drive the blocking member  214  to move from the first state S 1  to the second state S 2 , such that the blocking member  214  can drive the positioning member  206  to move from the first state S 1  to the second state S 2 , and that the positioning portion  208  of the positioning member  206  and the blocking portion  216  of the blocking member  214  no longer correspond to the two portions (e.g., the back portion  204   b  and the front portion  204   a  of the positioning feature  204  of the first rail  202 ), so as to allow the second rail  210  to move from the second extending position E 2  in the extending direction D 1  or the retracting direction D 2  relative to the first rail  202 . 
     As shown in  FIG.  28    and  FIG.  29   , when the second rail  210  is positioned at the second extending position E 2  relative to the first rail  202 , the user can also move the third rail  222  from the above-mentioned open position K in the retracting direction D 2  until the third rail  222  (e.g., the rear end  222   b  thereof) contacts an auxiliary section  224  of the blocking member  214  (as shown in FIG.  28 ), so that the blocking member  214  is driven to no longer be at the first state S 1 , and the blocking member  214  motivates the positioning member  206  to no longer be at the first state S 1  (as shown in  FIG.  29   ), such that the positioning portion  208  of the positioning member  206  and the blocking portion  216  of the blocking member  214  no longer respectively correspond to the two portions (e.g., the back portion  204   b  and the front portion  204   a ) of the positioning feature  204  of the first rail  202 , so as to allow the second rail  210  to move from the second extending position E 2  in the extending direction D 1  or the retracting direction D 2  relative to the first rail  202 , until the slide rail assembly  200  is in the above-mentioned fully retracted state. For example, the second rail  210  is positioned at the above-mentioned retracted position R relative to the first rail  202 , and the third rail  222  is also positioned at the predetermined retracted position relative to the second rail  210 . 
     The slide rail assembly  200  of the second embodiment of the present invention includes the feature: the positioning feature  204  of the first rail  202  can be a protrusion that protrudes laterally (horizontally) relative to the longitudinal wall  205  of the first rail  202 , and the positioning portion  208  of the positioning member  206  can be an extended arm. When the second rail  210  is positioned at the second extending position E 2  relative to the first rail  202 , the positioning portion  208  of the positioning member  206  at the first state S 1  and the blocking portion  216  of the blocking member  214  in the first state S 1  provide a blocking or engaging effect to prevent the second rail  210  from being moved from the second extending position E 2  in the extending direction D 1  or the retracting direction D 2  relative to the first rail  202 , through respectively corresponding to the two parts (e.g., the back portion  204   b  and the front portion  204   a ) of the positioning feature  204 . 
     As shown in  FIG.  30    and  FIG.  31   , a slide rail assembly  300  according to the third embodiment of the present invention is provided. The essential difference between the slide rail assembly  300  according to the third embodiment and the slide rail assembly  20  according to the above-mentioned first embodiment is that the recovering elastic member  64 , elastic member  90 , and the predetermined wall  112  of the second rail  24  that are mentioned above are omitted. 
     Specifically, the first rail  302  as shown in the third embodiment has a first auxiliary feature  304 , and the operating member  305  includes a second auxiliary feature  306  to be used in conjunction with the first auxiliary feature  304 . Here, both the first auxiliary feature  304  and the second auxiliary feature  306  are protrusions, but the present invention is not limited thereto. In addition, the operating member  305  has the engaging feature  308 , and the second rail  310  includes at least one predetermined portion, such as a first predetermined portion  312  and a second predetermined portion  314 , configured to be engaged with the engaging feature  308 , respectively, such that the operating member  305  can be retained at the first operating position P 1  (as shown in  FIG.  30   ) or the second operating position P 2  (as shown in  FIG.  31   ) relative to the second rail  310  when being positioned at in the first operating position P 1  or the second operating position P 2 . In the third embodiment, the engaging feature  308  is a connecting member (e.g., a screw or a pin) penetrating through at least part of the elongated hole  315  of the second rail  310 , and the first predetermined portion  312  and the second predetermined portion  314  are positioned in the elongated hole  315 . Preferably, each of the engaging feature  308 , the first predetermined portion  312 , and/or the second predetermined portion  314  includes a guiding surface (e.g., an inclined surface or a curved surface), such that the operating member  305  can be disengaged from the first operating position P 1  or the second operating position P 2  more easily. 
     Furthermore, the slide rail assembly  300  can be in the fully extended state. The second rail  310  is positioned at the first extending position E 1  relative to the first rail  302 , and the third rail  316  is positioned at the open position K relative to the second rail  310 . When the second rail  310  is positioned at the first extending position E 1 , the slide rail assembly  300  has a first length. When the second rail  310  is positioned at the first extending position E 1  relative to the first rail  302 , the blocking feature  318  blocks the blocking portion  322  of the blocking member  320  at the first state S 1  to prevent the second rail  310  from being moved in the retracting direction D 2  from the first extending position E 1  (as shown in  FIG.  30   ). On the other hand, the positioning member  324  contacts the guiding portion  330  of the elastic seat  328  of the first rail  302  through the positioning portion  326 . 
     The user can apply force F to the operating member  305  to move the operating member  305  from the first operating position P 1  (as shown in  FIG.  30   ) to the second operating position P 2  (as shown in  FIG.  31   ), and the driving portion  332  of the operating member  305  can drive the blocking member  320  to move (e.g. pivotally rotate) from the first state S 1  to the second state S 2  and retain the blocking member  320  in the second state S 2 , so that the blocking feature  318  cannot block the blocking portion  322  of the blocking member  320  in the second state S 2 , so as to allow the second rail  310  to move from the first extending position E 1  in the retracting direction D 2  relative to the first rail  302  (as shown in  FIG.  31   ). On the other hand, the blocking member  320  motivates the positioning member  324  (e.g., the blocking member  320  is connected to and motivates the positioning member  324  to pivotally rotate), so that the positioning member  324  is also at the second state S 2 . When the blocking member  320  and the positioning member  324  are at the second state S 2 , the first elastic feature  334  and the second elastic feature  336  are respectively in a state of accumulating the elasticity (as shown in  FIG.  31   ). 
     As shown in  FIG.  31    and  FIG.  32   , when the second rail  310  is moved relative to the first rail  302  from the first extending position E 1  in the retracting direction D 2 , the blocking portion  322  of the blocking member  320  at the second state S 2  and the positioning member  324  at the second state S 2  are not corresponding to the positioning feature  338  of the first rail  302  through the positioning portion  326 . Therefore, the blocking member  320  and the positioning member  324  can directly move in the retracting direction D 2  and cross over the positioning feature  338  of the first rail  302  (as shown in  FIG.  32   ), and when the second rail  310  is being moved in the retracting direction D 2  relative to the first rail  302  for a predetermined stroke, the second auxiliary feature  306  of the operating member  305  contacts the first auxiliary feature  304  of the first rail  302  (as shown in  FIG.  32   ). 
     As shown in  FIG.  32    and  FIG.  33   , when the second rail  310  further is moved in the retracting direction D 2  relative to the first rail  302 , a force is applied to the operating member  305  through the first auxiliary feature  304  blocking the second auxiliary feature  306 , such that the operating member  305  returns from the second operating position P 2  (as shown in  FIG.  32   ) to the first operating position P 1  (as shown in  FIG.  33   ) in the extending direction D 1  (as shown in  FIG.  33   ). and that the blocking member  320  and the positioning member  324  respectively return from the second state S 2  (as shown in  FIG.  32   ) to the first state S 1  (as shown in  FIG.  33   ) by the elasticity provided by the first elastic feature  334  and the second elastic feature  336 , respectively. In addition, the second rail  310  can continue to move relative to the first rail  302  in the retracting direction D 2  to the retracted position R (e.g., the fully retracted position, as shown in  FIG.  33   ). When the blocking member  320  and the positioning member  324  are at the first state S 1 , the blocking portion  322  of the blocking member  320  and the positioning portion  326  of the positioning member  324  can correspond to the positioning feature  338  of the first rail  302 . 
     As shown in  FIG.  34    and  FIG.  35   , when the second rail  310  is moved in the extending direction D 1  relative to the first rail  302  from the retracted position R for the predetermined stroke, the blocking portion  322  of the blocking member  320  at the first state S 1  is contacted with the back portion  338   b  of the positioning feature  338  of the first rail  302 . Preferably, one of the back portion  338   b  of the positioning feature  338  of the first rail  302  and the blocking portion  322  of the blocking member  320  has a guiding feature (e.g., an inclined surface or a curved surface), which facilitates the blocking portion  322  of the blocking member  320  to cross over the back portion  338   b  of the positioning feature  338  in the extending direction D 1 . 
     As shown in  FIG.  36    to  FIG.  38   , when the second rail  310  continues to move relative to the first rail  302  in the extending direction D 1  to the second extending position E 2 , the blocking member  320  is no longer at the first state S 1  through the blocking member  322  and the positioning feature  338  contacting each other (as shown in  FIG.  36   ). At this time, the first elastic feature  334  accumulates elasticity until the second rail  310  is moved in the extending direction D 1  relative to the first rail  302  to the second extending position E 2  (as shown in  FIG.  37    and  FIG.  38   ), the blocking member  320  responds to the elasticity from the first elastic feature  334  and is in the first state S 1  again (as shown in  FIG.  37    and  FIG.  38   ). At this time, the positioning portion  326  of the positioning member  324  at the first state S 1  and the blocking portion  322  of the blocking member  320  at the first state S 1  correspond to the two portions (e.g., the back portion  338   b  and the front portion  338   a , as shown in  FIG.  37   ) of the positioning feature  338 , respectively, which provides a blocking or engaging effect to prevent the second rail  310  from being moved from the second extending position E 2  in the extending direction D 1  or the retracting direction D 2  relative to the first rail  302  (as shown in  FIG.  37    and  FIG.  38   ). Similar to the first embodiment, when the second rail  310  is positioned at the second extending position E 2 , the slide rail assembly  300  has a second length shorter than the first length, which is beneficial for the third rail  316  to be disengaged from the second channel of the second rail  310  in the extending direction D 1 . When the second rail  310  is positioned at the second extending position E 2  relative to the first rail  302 , the blocking member  320  (and the positioning member  324 ) can also be driven by the operating member  305  or the third rail  316 , such that second rail  310  can be dislocated from the second extending position E 2  (which is disclosed in the above-mentioned second embodiment, and will not be reiterated herein for the sake of brevity). 
     It is worth mentioning that, referring further to  FIG.  31   , once the blocking member  320  is driven by the operating member  305  to be at the second state S 2 , and the blocking feature  318  is unable to block the blocking portion  322  of the blocking member  320  at the second state S 2 , during a process of the second rail  310  being moved from the first extending position E 1  in the retracting direction D 2  relative to the first rail  302 , if the operating member  305  is returned from the second operating position P 2  to the first operating position P 1  due to interferences or unexpected reasons, the driving portion  332  of the operating member  305  is unable to retain the blocking member  320  at the second state S 2  at this time being (for example, the blocking member  320  and the positioning member  324  returning to the first state S 1  through the elasticity of the first elastic feature  334  and the second elastic feature  336 ), so that the blocking portion  322  of the blocking member  320  and the positioning portion  326  of the positioning member  324  correspond to the positioning feature  338  of the first rail  302 . In such state, one of the front portion  338   a  of the positioning feature  338  of the first rail  302  and the positioning portion  326  of the positioning member  324  having the guiding feature (e.g., an inclined surface or a curved surface) facilitates the positioning portion  326  of the positioning member  324  crossing over the front portion  338   a  of the positioning feature  338  in the retracting direction D 2  and the second elastic feature  336  being in a state of accumulating elasticity, until the second rail  310  continues to move in the retracting direction D 2  to the second extending position E 2  (as shown in  FIG.  37    and  FIG.  38   ), the positioning member  324  responds to the elasticity from the second elastic feature  336  and is once again at the first state S 1  (as shown in  FIG.  37    and  FIG.  38   ). At this time, the positioning portion  326  of the positioning member  324  at the first state S 1  and the blocking portion  322  of the blocking member  320  at the first state S 1  correspond to the two portions (e.g; the back portion  338   b  and the front portion  338   a , as shown in  FIG.  37   ) of the positioning feature  338 , respectively, which provides a blocking or engaging effect to prevent the second rail  310  from being moved from the second extending position E 2  in the extending direction D 1  or the retracting direction D 2  relative to the first rail  302  (as shown in  FIG.  37    and  FIG.  38   ). 
     The slide rail assembly  300  according to the third embodiment of the present invention at least includes the following features: 
     1. The first rail  302  includes the first auxiliary feature  304 , and the operating member  305  includes the second auxiliary feature  306 . When the second rail  210  is moved in the retracting direction D 2  relative to the first rail  202  from the first extending position E 1  for the predetermined stroke, a force is generated to the operating member  305  through the second auxiliary feature  306  being blocked by the first auxiliary feature  304 , such that the operating member  305  on the second rail  210  can return from the second operating position P 2  to the first operating position P 1 , and that the blocking member  320  and the positioning member  324  respectively return to the first state S 1  from the second state S 2  via the elasticity from the first elastic feature  334  and the second elastic feature  336 , respectively. When the second rail  310  is moved relative to the first rail  302  in the extending direction D 1  to the second extending position E 2 , the positioning portion  326  of the positioning member  324  at the first state S 1  and the blocking portion  322  of the blocking member  320  at the first state S 1  respectively correspond to the two portions of the positioning feature  338 , respectively, which provides a blocking or engaging effect to prevent the second rail  310  from being moved from the second extending position E 2  in the extending direction D 1  or the retracting direction D 2  relative to the first rail  302 . 
     2. The operating member  305  includes the engaging feature  308 , and the second rail  310  includes the at least one predetermined portion, such as the first predetermined portion  312  and the second predetermined portion  314  configured to be engaged with the engaging feature  308 . The operating member  305  can be retained at the first operating position P 1  or the second operating position P 2  relative to the second rail  310 . 
     Those skilled in the art will readily observe that numerous modifications and alterations of the device and method may be made while retaining the teachings of the invention. Accordingly, the above disclosure should be construed as limited only by the metes and bounds of the appended claims.