TWI578639B - Electronic device and fastening module thereof - Google Patents

Description

Electronic device and its fixed module

The invention discloses an electronic device, in particular an electronic device with a fixed module.

The computer and server are assembled from components such as a central processing unit (CPU), memory, and input/output (I/O) devices, and are connected by a bus.

In general, interface cards (or sub-boards) installed in computers and servers are usually locked or riveted to the motherboard of a computer or server to prevent the interface card from falling off the motherboard. However, it is difficult to remove the interface card that is locked or riveted to the motherboard, which is not conducive to improving the maintenance efficiency of the computer or the server. In addition, with the development of the industry, computers and servers tend to be miniaturized, and the number of components installed inside is gradually increasing, so that the free space in the motherboard is reduced, and the space between the components is also narrowed. The user feels inconvenience when installing the interface card.

In view of the above problems, the present invention discloses an electronic device for conveniently fixing interface cards of different specifications, and can increase the number of installation interface cards in a limited internal space of the electronic device.

The invention discloses an electronic device comprising a casing, a motherboard, at least one fixing component, a fixing module and at least one interface card. The motherboard is placed in the chassis. The fixing member is fixed to the motherboard. The fixing module is fixed to the at least one fixing member away from one end of the motherboard, and comprises a circuit board, a first connector, a second connector and a snap member. The circuit board and the motherboard are respectively fixed to the two ends of the at least one fixing member and electrically connected to the motherboard, and have a sliding slot, an opposite top surface and a bottom surface. The chute extends through the top and bottom surfaces. The first connector and the second connector are respectively fixed to the top surface and the bottom surface of the circuit board. The engaging member comprises a sliding member, a first engaging portion and a second engaging portion. The sliding member is slidably disposed on the sliding slot to be slidable relative to the circuit board along the sliding slot to adjust the distance between the engaging member and the first connector and the second connector. The first engaging portion and the second engaging portion are respectively fixed to opposite sides of the sliding member corresponding to the first connector and the second connector. And the first engaging portion and the second engaging portion respectively protrude from the sliding member to the top surface and the bottom surface. The interface card has a first end and a second end. The first end is selectively inserted into the first connector and the second connector to electrically connect the circuit board, and the second end is selectively engaged with the first engaging portion and the second engaging portion, so that The interface card is sandwiched between the first connector and the first engaging portion or between the second connector and the second engaging portion.

The invention further discloses a fixing module for fixing at least one interface card. An interface card has a first end and a second end. The fixing module comprises a circuit board, a first connector, a second connector and a snap member. The circuit board has a chute, an opposite top surface and a bottom surface. The chute extends through the top and bottom surfaces. The first connector and the second connector are respectively fixed to the top surface and the bottom surface of the circuit board. The snap includes a sliding member, a first engaging portion and a second engaging portion. The sliding member is slidably disposed on the sliding slot to be slidable relative to the circuit board along the sliding slot to adjust the distance between the engaging member and the first connector and the second connector. The first engaging portion and the second engaging portion are respectively fixed to opposite sides of the sliding member. And the first engaging portion and the second engaging portion respectively protrude from the top surface and the bottom surface from the sliding member. The interface card has a first end and a second end. The first end is selectively inserted into the first connector and the second connector, and the second end is selectively engaged with the first engaging portion and the second engaging portion, so that the interface card is firstly Between the connector and the first engaging portion, or between the second connector and the second engaging portion.

In the electronic device disclosed in the present invention, the sliding member of the engaging member is slidably disposed on the sliding rail member, and the distance between the sliding member and the first connector and the second connector can be adjusted. Thereby, the position of the slider in the chute can be adjusted to conveniently install interface cards of various lengths. In addition, the circuit board of the fixed module is fixed to the motherboard through the fixing member, so that the circuit board has sufficient space to accommodate the interface card on one side of the motherboard and away from the side of the motherboard, thereby facilitating the electronic device in a limited space. Increase the number of interface cards.

The above description of the present invention and the following description of the embodiments of the present invention are intended to illustrate and explain the principles of the invention.

E‧‧‧Electronic device

1‧‧‧Shell

2‧‧‧ motherboard

20‧‧‧Slots

3‧‧‧Fixed parts

4‧‧‧Fixed modules

40‧‧‧ boards

400‧‧‧ chute

401‧‧‧First limit slot

402‧‧‧Second limit slot

403‧‧‧third limit slot

404‧‧‧4th limit slot

405‧‧‧5th limit slot

406‧‧‧ first side edge

407‧‧‧second side

410‧‧‧ top surface

420‧‧‧ bottom

41‧‧‧First connector

42‧‧‧Second connector

43‧‧‧Cards

430‧‧‧Sliding parts

430a‧‧‧Extension

4301‧‧‧Limited blocks

431‧‧‧First engagement department

431a‧‧‧ engaging section

4311‧‧‧Protruding

432‧‧‧Second engagement department

432a‧‧‧enging section

4321‧‧‧Protruding

433‧‧‧Press parts

5a, 5b, 5a’, 5b’‧‧‧ interface cards

51‧‧‧ first end

52‧‧‧ second end

53‧‧‧ concave edge

6‧‧‧Electrical insulation

1 is a perspective view of an electronic device according to a first embodiment of the present invention.

Fig. 2 is an exploded perspective view of Fig. 1.

Fig. 3 is an exploded perspective view showing the fixing module according to the first embodiment of the present invention.

Figure 4 is a side elevational view of a circuit board of a fixed module in accordance with a first embodiment of the present invention.

Fig. 5 is a top plan view showing a circuit board of a fixed module according to a first embodiment of the present invention.

FIG. 6A is a perspective view of the disassembled two-face card according to the first embodiment of the present invention.

Figure 6B is a top plan view of Figure 6A.

FIG. 7A is a perspective view showing the installation of another interface card according to the first embodiment of the present invention.

Figure 7B is a top plan view of Figure 7A.

Figure 8 is a side elevational view of a solid state module in accordance with a second embodiment of the present invention.

Figure 9 is another side elevational view of a solid state module in accordance with a second embodiment of the present invention.

The detailed features and advantages of the present invention are set forth in the Detailed Description of the Detailed Description of the <RTIgt; </ RTI> <RTIgt; </ RTI> </ RTI> </ RTI> <RTIgt; The objects and advantages associated with the present invention can be readily understood by those skilled in the art. The following examples are intended to describe the present invention in further detail, but are not intended to limit the scope of the invention.

Please refer to both Figure 1 and Figure 2. Figure 1 is a diagram of the invention A schematic perspective view of an electronic device of the first embodiment. Fig. 2 is an exploded perspective view of Fig. 1. In this embodiment, an electronic device E includes a casing 1, a motherboard 2, two fixing members 3, a fixed module 4, and two interface cards 5a and 5b.

The casing 1 is, for example, a computer main body casing or a server casing.

The motherboard 2 is disposed in the casing 1.

The two fixing members 3 are, for example, two metal brackets, which are all fixed to the motherboard 2 . The number of fasteners 3 is not intended to limit the invention. In other embodiments, the number of the fixing members 3 may be one.

The opposite ends of the fixing module 4 are respectively fixed to the two fixing members 3 . In this embodiment, the fixed module 4 includes a circuit board 40, a first connector 41, a second connector 42, and a latching member 43.

The structure of the fixed module is described below. Please also refer to Figures 3, 4 and 5. Fig. 3 is an exploded perspective view showing the fixing module according to the first embodiment of the present invention. Figure 4 is a side elevational view of a circuit board of a fixed module in accordance with a first embodiment of the present invention. Fig. 5 is a top plan view showing a circuit board of a fixed module according to a first embodiment of the present invention.

The opposite ends of the circuit board 40 are respectively fixed to the two fixing members 3 and electrically connected to the motherboard 2 . For example, the circuit board 40 can be electrically connected to the motherboard 2 through a signal connector (not shown). In addition, the circuit board 40 has a chute 400, a top surface 410, and a bottom surface 420. The top surface 410 and the bottom surface 420 are located on opposite sides of the circuit board 40, and the sliding slot 400 extends through the top surface 410 and the bottom surface 420.

The sliding slot 400 of the circuit board 40 further has two first limiting slots 401, The second limiting slot 402, the second limiting slot 403, the second and fourth limiting slots 404, and the second and fifth limiting slots 405. In detail, the chute 400 of the circuit board 40 has a first side edge 406 and a second side edge 407 opposite to each other. The two first limiting slots 401 are respectively located at the first side edge 406 and the second side edge 407 and face each other. The second second limiting slots 402 are respectively located at the first side edge 406 and the second side edge 407 and face each other. The second third limiting slots 403 are respectively located at the first side edge 406 and the second side edge 407 and face each other. The second and fourth limiting slots 404 are respectively located at the first side edge 406 and the second side edge 407 and face each other. The second and fifth limiting slots 405 are respectively located at the first side edge 406 and the second side edge 407 and face each other. The functions of the first limiting slot 401, the second limiting slot 402, the third limiting slot 403, the fourth limiting slot 404 and the fifth limiting slot 405 will be described later.

In this embodiment, the number and position of the limiting slots are not limited to the above. In other embodiments, the circuit board 40 can have only two first limiting slots 401 and two second limiting slots 402. In addition, in other embodiments, the number of the first limiting slot 401, the second limiting slot 402, the third limiting slot 403, the fourth limiting slot 404, and the fifth limiting slot 405 may be only one, and Each of the limiting slots may be located at the first side edge 406 or the second side edge 407.

The first connector 41 is fixed to the top surface 410 of the circuit board 40, and the second connector 42 is fixed to the bottom surface 420 of the circuit board 40. In detail, as shown in FIG. 5, the first limiting slot 401 has a distance D1 from the first connector 41, and the second limiting slot 402 has a distance D2 to the first connector 41. The third limiting slot The first connector 41 has a distance D3, the fourth limiting slot 404 has a distance D4 from the first connector 41, and the fifth limiting slot 405 has a distance D5 from the first connector 41. The distance D1 is smaller than the distance D2, the distance D2 is smaller than the distance D3, the distance D3 is smaller than the distance D4, and the distance D4 is smaller than the distance D5. Thereby, the fixed module 4 can be installed with interface cards of different lengths, and the details will be described later.

The engaging member 43 includes a sliding member 430 , a first engaging portion 431 , a second engaging portion 432 and two pressing members 433 . The sliding member 430 is slidably disposed on the sliding slot 400 of the circuit board 40, and the sliding member 430 is slidable relative to the sliding slot 400 toward or away from the first connector 41 and the second connector 42 to adjust the engagement. The distance from the piece 43 to the first connector 41 and the second connector 42. Additionally, the slider 430 extends along the first side edge 406 and the second side edge 407 of the circuit board 40 to form two extensions 430a. The two extensions 430a each have a limit block 4301. The limiting block 4301 matches the first limiting slot 401, the second limiting slot 402, the third limiting slot 403, the fourth limiting slot 404 and the fifth limiting slot 405. The limiting block 4301 can be selectively engaged with the first limiting slot 401, the second limiting slot 402, the third limiting slot 403, the fourth limiting slot 404 or the fifth limiting slot 405. The slider 430 is fixed to the circuit board 40.

The first engaging portion 431 and the second engaging portion 432 are respectively fixed to opposite sides of the sliding member 430 corresponding to the first connector 41 and the second connector 42 , and the first engaging portion 431 and the second engaging portion 432 . The top surface 410 and the bottom surface 420 of the circuit board 40 protrude from the slider 430, respectively. The first engaging portion 431 has an engaging portion 431a, and the second engaging portion 432 has an engaging portion 432a. The engaging portion 431a includes two protrusions 4311, and the engaging portion 432a includes two protrusions 4321, but the number of the protrusions 4311 and 4321 is not limited thereto. In other embodiments, the first engaging portion 431 and the second engaging portion 432 may also have a plurality of protrusions 4311 and protrusions 4321, respectively.

The two pressing members 433 are respectively fixed to the two extending portions 430a of the sliding member 430. The two pressing members 433 can be biased to bring the two extending portions 430a closer to each other, thereby disengaging the limiting block 4301 from the limiting slot. Further, the pressing member 433 is biased to move the two extending portions 430a away from each other at one end of the first engaging portion 431 to disengage the limiting block 4301 from the first limiting slot 401 and the second limiting slot 402. The third limiting slot 403, the fourth limiting slot 404 or the fifth limiting slot 405. Thereby, the slider 430 can slide relative to the sliding slot 400 of the circuit board 40 to change the distance of the first engaging portion 431 to the first connector 41 and change the second engaging portion 432 to the second connector 42. distance.

The two interface cards 5a and 5b are, for example, a solid state hard disk, a wireless network card or a graphics card, and are not limited thereto. The two interface cards 5a and 5b each have an opposite first end 51 and a second end 52, and the two interface cards 5a and 5b each have a concave edge 53 at the second end 52. The concave edge 53 of the interface card 5a is engaged between the two protrusions 4311 of the first engaging portion 431 so that the first end 52 of the interface card 5a is engaged with the first engaging portion 431. The first end 51 of the interface card 5a is inserted into the first connector 41. Thereby, the interface card 5a is interposed between the first connector 41 and the first engaging portion 431, and is electrically connected to the circuit board 40 by the first connector 41. The recessed edge 53 of the interface card 5b is fastened between the two protrusions 4321 of the second engaging portion 432 to engage the second end 52 of the interface card 5b with the second engaging portion 432. The first end 51 of the interface card 5b is inserted into the second connector 42. Thereby, the interface card 5b is interposed between the second connector 42 and the second engaging portion 432, and is electrically connected to the circuit board 40 by the second connector 42.

In addition, the electronic device E further includes two electrical insulating members 6. Electrical The edge member 6 is, for example, a rubber pad, and is interposed between the fixing member 3 and the circuit board 40 of the fixed module 4 to connect the fixing member 3 and the circuit board 40.

In addition, in the present embodiment, the first connector 41 and the second connector 42 are electrically connected to the circuit board 40, respectively, and the first connector 41 is projected onto the circuit board 40 to have a first projection. In the range P1, the second connector 42 is projected onto the circuit board 40 to have a second projection range P2, and the first projection range P1 and the second projection range P2 may not overlap each other. Thereby, it helps to properly configure the trace distribution of the circuit board 40.

Furthermore, the circuit board 40 of the fixed module 4 is fixed to the fixing member 3 so that the circuit board 40 of the fixed module can be arranged in a superimposed manner with the main board 2 and maintain a spacing H, and the spacing H is greater than or equal to the thickness of the interface card 5b. . The motherboard can have at least one slot 20 for an electronic component (not shown) to be inserted into the motherboard 2, and the fixing module 4 can shield the slot 20.

The following describes how to remove the interface card. Please refer to both Figure 6A and Figure 6B. FIG. 6A is a perspective view of the disassembled two-face card according to the first embodiment of the present invention. Figure 6B is a top plan view of Figure 6A.

In this embodiment, the limiting block 4301 of the sliding member 430 is engaged with the first limiting slot 401, and the interface card 5a is sandwiched between the first connector 41 and the first engaging portion 431, and the interface card is 5b is interposed between the second connector 42 and the second engaging portion 432 (please refer to FIG. 1).

When the user needs to disassemble the two interface cards 5a and 5b, an external force F is pressed against the two pressing members 433 to bring the two extending portions 430a closer to each other (as shown in FIG. 6B). As shown, the two limit blocks 4301 are respectively separated from the two first limit slots 401. When the limiting block 4301 is disengaged from the first limiting slot 401, the driving slider 430 slides in a direction R relative to the circuit board 40 along the sliding slot 410 to generate a certain amount between the first connector 41 and the first engaging portion 431. The disassembly distance allows the user to smoothly remove the interface card 5a. In addition, when the slider 430 slides in the direction R along the sliding slot 410 relative to the circuit board 40, the disassembly distance is also generated between the second connector 42 and the second engaging portion 432, so that the user can smoothly disassemble the interface. Card 5b.

The following describes how to install the interface card. Please refer to both Figure 7A and Figure 7B. FIG. 7A is a perspective view showing the installation of another interface card according to the first embodiment of the present invention. Figure 7B is a top plan view of Figure 7A.

When the user needs to replace the two interface cards 5a and 5b with the two interface cards 5a' and 5b' having a larger length, the user first removes the two interface cards 5a and 5b in the above manner. After the user disassembles the two interface cards 5a and 5b, the driving slider 430 slides along the sliding slot 400 with respect to the circuit board 40, and a certain loading distance is generated between the first connector 41 and the first engaging portion 431. The user can insert the interface card 5a' into the first connector 41. In addition, as the sliding key 430 slides along the sliding slot 400 relative to the circuit board 40, a certain loading distance is also generated between the second connector 42 and the second engaging portion 432, so that the user can insert the interface card 5b'. Provided in the second connector 42. Then, the driving slider 430 is slid along the sliding slot 400 to the second limiting slot 402, and the external force F is removed, so that the two limiting blocks 4301 are respectively engaged with the second limiting slots 402, thereby The slider 430 is fixed to the circuit board 40. When the slider 430 is fixed to the circuit board 40, the interface card 5a' is sandwiched between the first connector 41 and the first engaging portion. Between the 431 (that is, the interface card 5a' is engaged with the first engaging portion 431 and inserted into the first connector 41), and at the same time, the interface card 5b' is sandwiched between the second connector 42 and the second connector Between the portions 432 (that is, the interface card 5b' is engaged with the second engaging portion 432 and inserted into the second connector 42).

In summary, since the slider 430 of the engaging member 43 is slidably disposed on the chute 400, the distance between the first connector 41 and the first engaging portion 431 can be changed, and the second connector 42 to the second The distance of the engaging portion 432. Thereby, the user can adjust the position of the sliding member 430 at the sliding slot 400 to conveniently install the interface cards of various lengths, which helps to increase the number of interface cards in the electronic device E in a limited space.

In addition, the sliding slot 400 of the circuit board 40 has a first limiting slot 401, a second limiting slot 402, a third limiting slot 403, a fourth limiting slot 404 and a fifth limiting slot 405. Therefore, the fixed module 4 can be mounted on the interface card of the two lengths by engaging the limiting block 4301 with the first limiting slot 401 and the second limiting slot 402. Three other interface cards of different lengths are installed by engaging the limiting block 4301 in the third limiting slot 403, the fourth limiting slot 404 and the fifth limiting slot 405.

In the above embodiment, the first interface card and the second interface card are simultaneously mounted on the fixed module, but the invention is not limited thereto. Please refer to Figure 8 and Figure 9. Figure 8 is a side elevational view of a solid state module in accordance with a second embodiment of the present invention. Figure 9 is a side elevational view of a solid state module in accordance with a second embodiment of the present invention. Since this embodiment is similar to the first embodiment, the following description will be made only for differences.

In this embodiment, only the interface card 5a is fixed to the fixed module 4, It is sandwiched between the first connector 41 and the first engaging portion 431 (as shown in FIG. 8), but is not limited thereto. In this embodiment, the interface card 5a may also be interposed between the second connector 42 and the second engaging portion 432 (as shown in FIG. 9).

In summary, in the electronic device disclosed in the present invention, the sliding member of the engaging member is slidably disposed on the sliding rail member, and the distance between the sliding member and the first connector and the second connector can be adjusted. Thereby, the position of the slider in the chute can be adjusted to conveniently install interface cards of various lengths. In addition, the circuit board of the fixed module is fixed to the motherboard through the fixing member, so that the circuit board has sufficient space to accommodate the interface card on one side of the motherboard and away from the side of the motherboard, thereby facilitating the electronic device in a limited space. Increase the number of interface cards.

While the present invention has been described above in terms of the preferred embodiments thereof, it is not intended to limit the invention, and the invention may be modified and modified without departing from the spirit and scope of the invention. The patent protection scope of the invention is subject to the definition of the scope of the patent application attached to the specification.

E‧‧‧Electronic device

H

1‧‧‧Shell

2‧‧‧ motherboard

20‧‧‧Slots

3‧‧‧Fixed parts

4‧‧‧Fixed modules

41‧‧‧First connector

42‧‧‧Second connector

5a, 5b‧‧‧ interface card

Claims (12)

An electronic device comprising: a casing; a motherboard disposed on the casing; at least one fixing member fixed to the motherboard; a fixing module comprising: a circuit board, respectively fixed to the motherboard The circuit board is electrically connected to the main board, and has a sliding slot, an opposite top surface and a bottom surface, the sliding slot extends through the top surface and the bottom surface; a first connector Fixed to the top surface of the circuit board; a second connector fixed to the bottom surface of the circuit board; and a latching member including a sliding member, a first engaging portion and a second engaging portion The sliding member is slidably disposed in the sliding slot, and the distance between the sliding member and the first connector and the second connector is adjustable, and the first engaging portion and the second engaging portion are respectively respectively Fixed to opposite sides of the slider and respectively corresponding to the first connector and the second connector; and at least one interface card having an opposite first end and a second end, the first end optionally Plugged into the first connector and the second connector to be electrically connected to the electric And the second end is selectively engaged with the first engaging portion and the second engaging portion, and the at least one interface card is sandwiched between the first connector and the first engaging portion Interposed between the second connector and the second engaging portion. The electronic device of claim 1, wherein the circuit board of the fixed module and the The motherboards are stacked and maintained at a pitch greater than or equal to the thickness of the at least one interface card. The electronic device of claim 1, wherein the motherboard has a slot, and the fixing module is fixed to the motherboard to shield the slot. The electronic device of claim 1, further comprising at least one electrical insulating member interposed between the at least one fixing member and the circuit board to connect the at least one fixing member and the circuit board. The electronic device of claim 1, wherein the first connector and the second connector are electrically connected to the circuit board, respectively, and the first connector is projected onto the circuit board to have a first projection range. The second connector is projected onto the circuit board to have a second projection range, and the first projection range and the second projection range do not overlap. The electronic device of claim 1, wherein the number of the at least one interface card is two, each of the two interface cards has an opposite first end and the second end, and each of the two interface cards has the same a recessed edge of the second end, the first engaging portion and the second engaging portion each having two protrusions, the concave edge being sandwiched between the two protrusions, so that the two interface cards are respectively associated with the first The engaging portion and the second engaging portion are engaged. The electronic device of claim 1, wherein the sliding member extends along the sliding slot to form an extending portion, the extending portion has a limiting block, and the sliding slot of the circuit board further has a matching matching block. The first limiting slot and the second limiting slot are selectively engageable with the first limiting slot or the second limiting slot to fix the sliding member to the circuit board. The electronic device of claim 1, wherein the chute of the circuit board has a relative a first side edge and a second side edge, the sliding member extending along the first side edge and the second side edge to form two extension portions, each of the two extension portions having a limiting block, the circuit board The sliding slot further has two first limiting slots and two second limiting slots that match the two limiting blocks, and the two first limiting slots are respectively located on the first side edge and the second side edge and face each other The second limiting slots are respectively located on the first side edge and the second side edge and face each other, and the two limiting blocks are selectively engageable with the two first limiting slots or the second second A limiting slot is provided to fix the slider to the circuit board. The electronic device of claim 8, wherein the engaging member further comprises two pressing members, wherein the two pressing members are respectively fixed to the two extending portions, and the two pressing members are respectively driven by an external force to drive the two extending portions to each other. The two limiting blocks are respectively separated from the two first limiting slots or the second second limiting slots. A fixed module for fixing at least one interface card, the at least one interface card having a first end and a second end, the fixing module comprising: a circuit board having a sliding slot and a top a top surface and a bottom surface, the sliding slot penetrating the top surface and the bottom surface; a first connector fixed to the top surface of the circuit board; a second connector fixed to the bottom surface of the circuit board; and a card The sliding member includes a sliding member, a first engaging portion and a second engaging portion. The sliding member is slidably disposed in the sliding slot, and the sliding member is adjustable to the first connector and the The distance between the first connector and the second connector are respectively fixed on opposite sides of the slider and respectively correspond to the first connector and the second connector; The first end of the at least one interface card is selectively inserted into the first connector and the second connector to be electrically connected to the circuit board, and the second end of the at least one interface card is The card is selectively engaged with the first engaging portion and the second engaging portion, and the at least one interface card is sandwiched between the first connector and the first engaging portion, or is sandwiched between the first connector and the first engaging portion. Between the second connector and the second engaging portion. The fixing module of claim 10, wherein the sliding slot of the circuit board has an opposite first side edge and a second side edge, the sliding member extending along the first side edge and the second side edge And forming a second extension portion, each of the two extension portions has a limiting block, the sliding slot of the circuit board further has two first limiting slots and two second limiting slots for matching the two limiting blocks, the second a limiting slot is located at the first side edge and the second side edge and faces each other, and the second limiting slots are respectively located at the first side edge and the second side edge and face each other, the second limit The block can be selectively engaged with the two first limiting slots or the second limiting slots to fix the slider to the circuit board. The fixing module of claim 11, wherein the engaging member further comprises two pressing members, wherein the two pressing members are respectively fixed to the two extending portions, and the two pressing members are respectively driven by an external force to drive the two extending portions. The two limiting blocks are respectively separated from the two first limiting slots or the second second limiting slots.