A mating system suitable for Type-C electrical connector male end

Abstract

The present invention relates to a mating system suitable for the male end of a Type-C electrical connector, comprising a front feed line, a rear feed line, a material handling unit and a material pushing unit. The front feed line is used to convey a male metal front shell, and a front circulation channel is provided on the front feed line. A placement groove intersecting with the front circulation channel is also provided on the front feed line for placing a male metal back shell to be mated. The rear feed line is used to convey a male metal back shell, and a rear circulation channel is provided on the rear feed line. A material taking and avoiding gap intersecting with the rear circulation channel is also provided on the rear feed line. The male metal back shell is transferred to the placement groove through the material taking and avoiding gap by the material handling unit. The material pushing unit is positioned relative to the placement groove. When the male metal back shell is placed in the placement groove and the male metal front shell is parked in place relative to the placement groove, the material pushing unit is actuated to push the male metal back shell to perform translational movement toward the male metal front shell.

Description

Technical Field

[0001] The present invention relates to the technical field of Type-C electrical connector manufacturing, and in particular to an insertion and mating system applicable to the male end of a Type-C electrical connector. Background Art

[0002] USB is the abbreviation of Universal Serial BUS in English, and its Chinese abbreviation is "universal serial line". It is an external bus standard used to standardize the connection and communication between a computer and external devices, and is an interface technology applied in the PC field. USB was jointly proposed by multiple companies such as Intel, Compaq, IBM, and Microsoft at the end of 1994. USB not only has a fast transmission speed but is also very convenient to use. The USB interface also has the advantages of supporting plug-and-play and hot-plugging of devices, flexible connection, independent power supply, etc. It can be connected to a mouse, keyboard, printer, scanner, camera, flash drive, MP3 player, mobile phone, digital camera, external hard drive, external optical or floppy drive, USB network card, ADSL Modem, Cable Modem, etc. Almost all external devices are equipped with a USB interface and are very widely used.

[0003] The male end of a USB Type-C electrical connector is a connection interface of the USB interface. It can be inserted regardless of the front or back, and like other interfaces, it supports functions such as USB-standard charging, data transmission, and display output. USB Type-C is mainly aimed at thinner and more slender devices, enhancing usability and paving the way for performance enhancement in future USB versions.

[0004] The male end of a USB Type-C electrical connector is mainly formed by inserting and mating a male front metal shell and a male rear metal shell and then spot welding them. In the past, the insertion and mating work of the male front metal shell and the male rear metal shell was all completed manually. In this way, on the one hand, it is known that the male front metal shell and the male rear metal shell are relatively small in size, which is not conducive to workers' gripping, making it very difficult to perform manual assembly operations, resulting in extremely low assembly efficiency; on the other hand, it has relatively high requirements for workers' proficiency and responsibility. Even so, there will inevitably be a phenomenon of incomplete insertion during the assembly operation, ultimately affecting the forming size of the male end of the Type-C electrical connector. Therefore, it is urgent for technical personnel to solve the above problems. Summary of the Invention

[0005] Therefore, in view of the above existing problems and defects, the designers of the present invention collected relevant materials, through multi-party evaluation and consideration, and through continuous experiments and modifications by technical personnel with many years of R & D experience in this industry, finally led to the emergence of the insertion and mating system applicable to the male end of a Type-C electrical connector.

[0006] In order to solve the above technical problems, the present invention relates to a mating system suitable for the male end of a Type-C electrical connector, which includes a front feed line, a rear feed line, a material handling unit and a material pushing unit. The front feed line is used to convey the male metal front shell, and a front circulation channel for the male metal front shell to flow is provided on it. A placement groove that is interlinked with the front circulation channel is also provided on the front feed line to be used for placing the male metal back shell to be mated. The rear feed line is arranged in parallel to the rear of the front feed line to convey the male metal back shell, and a rear circulation channel for the male metal back shell to flow is provided on it. A material collection avoidance gap that is interlinked with the rear circulation channel is also provided on the rear feed line. The material handling unit spans the front feed line and the rear feed line at the same time to transfer the male metal back shell to the placement groove through the material collection avoidance gap. The material pushing unit is arranged directly behind the front feed line and is opposite to the placement groove. When the male metal rear shell is placed in the placement groove and the male metal front shell is parked in place relative to the placement groove, the pushing unit is actuated to push the male metal rear shell to perform translational movement toward the male metal front shell until the male metal rear shell is plugged into the male metal front shell.

[0007] As a further improvement of the technical solution of the present invention, the material handling unit includes a support frame, a first power drive unit, a second power drive unit and an equidistant material distribution arm. The first power drive unit and the second power drive unit are both supported by the support frame to drive the equidistant material distribution arm to perform displacement movements along the front-to-back direction and the up-and-down direction respectively. The equidistant material distribution arm includes a base plate, a tension plate, a distribution block, a cylinder and a rear vacuum adsorption assembly. A distribution cavity is provided on the base plate. The tension plate crosses the distribution cavity and is directly driven by the cylinder. The number of distribution blocks is set to be multiple, built into the distribution cavity, and all are sleeved on the tension plate. A limit step is provided on the tension plate along its length direction. The number of the limit steps is consistent with the number of distribution blocks, and they are arranged at equal intervals, and the limit positions of the distribution blocks are limited one by one. The number of the rear vacuum adsorption assemblies is consistent with the number of distribution blocks, and they are fixed on the distribution blocks one by one and detachably, so as to directly adsorb the male end metal back shell.

[0008] As a further improvement of the technical solution of the present invention, the mating system suitable for the male end of the Type-C electrical connector also includes a transfer platform. The transfer platform is arranged between the front feed line and the rear feed line, and is provided with a material transfer groove for placing the male metal back shell. The material handling unit also includes an auxiliary transfer arm. The auxiliary transfer arm is arranged directly in front of the equidistant material dividing arm to transfer the male metal back shell from the material transfer groove to the placement groove. Assuming that the distance between the material transfer groove and the material avoidance gap is set to d1, the distance between the material transfer groove and the placement groove is set to d2, and the distance between the auxiliary transfer arm and the equidistant material dividing arm is set to d3, then d1=d2=d3.

[0009] As a further improvement of the technical solution of the present invention, the auxiliary transfer arm includes a mounting base plate and a front vacuum adsorption component. The number of the front vacuum adsorption components is set to be multiple, and all of them can be detachably fixed on the mounting base plate and are arranged at equal intervals.

[0010] As a further improvement of the technical solution of the present invention, the pusher unit includes a third power drive unit and a pusher assembly. The pusher assembly moves in a forward and backward direction under the driving force of the third power drive unit, and is composed of a plurality of pusher rods corresponding to the positions of the placement grooves. A sliding groove is provided on the front feed line for the pusher rods to pass through and communicate with the placement groove.

[0011] Before the mating operation is officially performed, the male metal front shell is transported via the front feeding line and stops corresponding to the placement groove; and the male metal back shell is transported via the rear feeding line until it is translated to be aligned with the material collection avoidance gap; when the male metal front shell is parked in the front circulation channel, the male metal back shell is transferred to the placement groove through the material collection avoidance gap by the material handling unit, thus realizing the alignment operation of the male metal back shell relative to the male metal front shell; then, the pushing unit is activated to push the male metal back shell to move toward the male metal front shell for translation until the mating operation of the male metal back shell in the male metal front shell is completed. From the above description, it can be seen that the mating operation of the male metal front shell and the male metal back shell is fully automated without the need for worker operation, thereby greatly improving the mating efficiency of the male end of the electrical connector. In addition, the use of a mating system suitable for the male end of the Type-C electrical connector also effectively ensures the mating quality of the male end of the electrical connector, eliminating the occurrence of mis-mating or inadequate mating or over-mating problems caused by improper mating force. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0013] Figure 1 It is a structural schematic diagram of the male end of the Type-C electrical connector in the present invention (showing both the pre-mated state and the mated state).

[0014] Figure 2 It is a schematic diagram of the relative positions of the plug-in system applicable to the male end of the Type-C electrical connector in the automatic spot welding machine for the male end of the Type-C electrical connector in the present invention.

[0015] Figure 3 It is a three-dimensional schematic diagram of a mating system suitable for a male end of a Type-C electrical connector in the present invention.

[0016] Figure 4 It is a three-dimensional schematic diagram of a front feed line in a mating system applicable to a male end of a Type-C electrical connector of the present invention.

[0017] Figure 5 yes Figure 4 A partial enlarged view of I.

[0018] Figure 6 It is a three-dimensional schematic diagram of a rear feed line in a mating system applicable to a male end of a Type-C electrical connector of the present invention.

[0019] Figure 7 yes Figure 6 A partial enlarged view of II.

[0020] Figure 8 It is a three-dimensional schematic diagram of a first viewing angle of a material handling unit in a mating system applicable to a male end of a Type-C electrical connector of the present invention.

[0021] Fig. 9 It is a stereoscopic schematic diagram of a second viewing angle of a material handling unit in a mating system applicable to a male end of a Type-C electrical connector of the present invention.

[0022] Fig.10 It is a three-dimensional schematic diagram of the equidistant material dividing arms in the material handling unit of the present invention (in an equidistant open state).

[0023] Fig.11 It is also a three-dimensional schematic diagram of the equidistant material dividing arms in the material handling unit of the present invention (in a closed state).

[0024] Fig.12It is a three-dimensional schematic diagram of the tension plate in the material handling unit of the present invention.

[0025] Fig.13 It is a three-dimensional schematic diagram of the auxiliary transfer arm in the material handling unit of the present invention.

[0026] Fig.14 It is a three-dimensional schematic diagram of a pusher unit in a mating system applicable to a male end of a Type-C electrical connector of the present invention.

[0027] Fig.15 yes Fig.14 Side view of.

[0028] Fig.16 It is a three-dimensional schematic diagram of a transfer platform in a mating system applicable to a male end of a Type-C electrical connector of the present invention.

[0029] Fig.17 yes Figure 3 Left view of .

[0030] 1-front feeding line; 11-front circulation channel; 12-placing groove; 13-sliding groove; 2-rear feeding line; 21-rear circulation channel; 22-material collection avoidance gap; 3-material handling unit; 31-support frame; 32-first power drive unit; 33-second power drive unit; 34-equidistant material distribution arm; 341-base plate; 3411-material distribution chamber; 342-tension plate; 3421-limiting step; 343-material distribution block; 344-cylinder; 345-rear vacuum adsorption assembly; 35-auxiliary transfer arm; 351-installation base plate; 352-front vacuum adsorption assembly; 4-push unit; 41-third power drive unit; 42-push assembly; 421-push rod; 5-transfer platform; 51-material transfer groove. DETAILED DESCRIPTION

[0031] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by the terms "up", "down", "left", "right", "front", "back", etc. are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention.

[0032] In order to facilitate those skilled in the art to fully understand the technical solutions disclosed in the present invention, the present invention is further described in detail below in conjunction with specific embodiments. Figure 1The schematic diagram of the structure of the Type-C electrical connector male end in the present invention shows that it includes a material strip and an electrical connector male end. The number of electrical connector male ends is set to multiple, all connected side by side to the metal material strip. The electrical connector male end is formed by a male end metal front shell and a male end metal rear shell that are plugged into each other and fixed by spot welding.

[0033] Figure 2 A schematic diagram of the relative position of the plug-in system for the male end of the Type-C electrical connector in the present invention in the automatic spot welding machine for the male end of the Type-C electrical connector is shown. It can be seen that the plug-in system for the male end of the Type-C electrical connector is arranged between the loading station and the welding station, and the male end metal front shell and the male end metal rear shell supplied by the loading station are plugged and fixed by welding at the subsequent welding station.

[0034] Figure 3 The 3D schematic diagram of the mating system for the male end of the Type-C electrical connector in the present invention is shown. It can be seen that it is mainly composed of a front feed line 1, a rear feed line 2, a material handling unit 3, and a material pushing unit 4. Among them, the front feed line 1 is used to transport the male metal front shell, and a front circulation channel 11 for the male metal front shell to flow is opened on it. The front feed line 1 is also provided with a placement groove 12 that is connected to the above-mentioned front circulation channel 11, so as to place the male metal rear shell to be mated (such as Figure 4 , 5 The rear feed line 2 is arranged in parallel to the rear of the front feed line 1 to transport the male metal rear shell, and a rear flow channel 21 is provided on the rear feed line 2 for the male metal rear shell to flow. The rear feed line 2 is also provided with a material taking avoidance gap 22 (as shown in FIG. Figure 6 , 7 ). The material handling unit 3 simultaneously crosses the front conveying line 1 and the rear conveying line 2 to transfer the male metal rear shell to the placement groove 12 through the material taking avoidance gap 22. The material pushing unit 4 is arranged directly behind the front conveying line 1 and is opposite to the placement groove 12. When the male metal rear shell is placed in the placement groove 12 and the male metal front shell is parked in place relative to the placement groove 12, the material pushing unit 4 is activated to push the male metal rear shell to perform translational movement toward the male metal front shell until the male metal rear shell is plugged into the male metal front shell. By adopting the above technical solution, on the one hand, the process of plugging and mating the male metal front shell and the male metal rear shell is fully automated without the need for worker operation, which not only greatly improves the plugging and mating efficiency of the male end of the electrical connector, but also reduces labor costs; on the other hand, it also effectively ensures the plugging and mating quality of the male end of the electrical connector, and eliminates the occurrence of wrong plugging or inadequate plugging or over-plugging problems caused by inappropriate plugging force.

[0035] The working principle of the above-mentioned mating system applicable to the male end of the Type-C electrical connector is roughly as follows: before the mating operation is officially performed, the male metal front shell is conveyed via the front material feeding line 1 and is parked corresponding to the placement groove 12; and the male metal rear shell is conveyed via the rear material feeding line 2 until it is translated to be aligned with the material collection avoidance gap 22; when the male metal front shell is parked in the front circulation channel 11, the male metal rear shell is transferred to the placement groove 12 through the material collection avoidance gap 22 by the material handling unit 3, thereby realizing the alignment operation of the male metal rear shell relative to the male metal front shell; then, the pushing unit 4 is activated to push the male metal rear shell to translate toward the male metal front shell until the mating operation of the male metal rear shell in the male metal front shell is completed.

[0036] As a further refinement of the above-mentioned mating system structure applicable to the male end of the Type-C electrical connector, Figure 8 , 9 As shown in , the material handling unit 3 preferably includes a support frame 31, a first power drive unit 32, a second power drive unit 33 and an equidistant material distribution arm 34. The first power drive unit 32 and the second power drive unit 33 are both supported by the support frame 31 to drive the equidistant material distribution arm 34 to perform displacement movement along the front-back direction and the up-down direction respectively. The equidistant material distribution arm 34 includes a base plate 341, a tension plate 342, a distribution block 343, a cylinder 344 and a rear vacuum adsorption component 345. A distribution cavity 3411 is provided on the base plate 341. The tension plate 342 crosses the distribution cavity 3114 and is directly driven by the cylinder 344. The number of distribution blocks 343 is set to 4, which are built into the distribution cavity 3411 and are all sleeved on the tension plate 342. Along the length direction, four equally spaced limiting steps 3421 are provided on the tension plate 342, and the limit positions of the material dividing block 343 are limited one by one. The number of the rear vacuum adsorption components 345 is set to 4, which are detachably fixed on the material dividing block 343 one by one, so as to directly adsorb the male metal rear shell (such as Fig.10 , 12 By adopting the above technical solution, the material handling unit 3 can simultaneously realize the transfer operation of 4 male metal rear shells through a single action, which not only effectively ensures that the material handling unit 3 has a very high working efficiency, but also reduces the energy consumption cost.

[0037] Before the material picking operation is performed on the male metal rear shell, each dividing block 343 performs a closing action under the action of the driving force of the tension plate 342, and then the first power drive unit 32 and the second power drive unit 33 are linked so that the four rear vacuum adsorption components 345 can be simultaneously placed in the material picking avoidance gap 22 to perform the synchronous material picking operation of the four male metal rear shells; then, the tension plate 342 is moved again, and the dividing blocks 342 perform a separation movement under the action of the driving force, and are spaced at equal intervals by the blocking effect of the limiting step 3421 until they are aligned with the four placement grooves 12 for pre-receiving the male metal rear shell; finally, the first power drive unit 32 and the second power drive unit 33 are linked again to transfer the male metal rear shell from the material picking avoidance gap 22 directly to the placement groove 12 (such as Figure 3 , 10 , as shown in 11).

[0038] It is known that the pusher unit 4 can adopt a variety of design structures to realize the push operation of the male metal rear shell. However, a design structure is simple, easy to implement, and easy to perform subsequent maintenance operations. The specific implementation is as follows: Fig.14 , 15 As shown in the figure, the pusher unit 4 preferably includes a third power driving part 41 and a pusher assembly 42. The pusher assembly 42 performs translational movement along the front-back direction under the driving force of the third power driving part 41, and is composed of four pusher rods 421 corresponding to the positions of the placement grooves 12. A sliding groove 13 (such as the one shown in FIG. 1 ) is provided on the front feed line 1 for the pusher rod 421 to pass through and communicate with the placement groove 12. Figure 4 , 5 When the male metal rear shell is placed in the placement groove 12, the third power driving part 41 is started to drive the push rod 421 to slide along the sliding groove 13, pushing the male metal rear shell to move toward the male metal front shell until it is plugged in, that is, the plugging operation of the male end of the electrical connector is realized.

[0039] When actually performing the pushing operation on the male metal back shell, the setting of the sliding groove 13 can effectively make the pushing rod 421 have good guiding properties during the displacement process, thereby ensuring the precise pushing of the male metal back shell, ensuring that it has a higher mating accuracy relative to the male metal front shell, and avoiding the occurrence of "bulging" of the male metal front shell caused by tilted insertion.

[0040] During the prototype experiment, it was found that the mating system for the male end of the Type-C electrical connector still had the following problem: when the operation of transferring the male end metal back shell from the material removal avoidance gap 22 to the placement groove 12 is performed, the equidistant material distribution arm 34 used to directly perform the transfer action has a long displacement path, which seriously limits the possibility of further improving the transfer efficiency of the male end metal back shell. In view of this, if Figure 3 , 8 As shown in the figure, as a further optimization of the above-mentioned plug-in system structure applicable to the male end of the Type-C electrical connector, a transfer platform 5 is also added. At the same time, the material handling unit 3 is additionally provided with an auxiliary transfer arm 35 matched with the transfer platform 5. The transfer platform 5 is arranged between the front material feeding line 1 and the rear material feeding line 2, and a material transfer groove 51 (such as Fig.16 The auxiliary transfer arm 35 is arranged in front of the equidistant material distribution arm 34 to transfer the male metal rear shell from the material transfer groove 51 to the placement groove 12. Fig.13 As shown in , the auxiliary transfer arm 35 includes a mounting base 351 and a front vacuum adsorption assembly 352. The number of the front vacuum adsorption assemblies 352 is set to 4, which can be detachably fixed on the mounting base 351 and are arranged at equal intervals. Assuming that the distance between the material transfer groove 51 and the material removal avoidance gap 22 is set to d1, the distance between the material transfer groove 51 and the placement groove 12 is set to d2, and the distance between the auxiliary transfer arm 35 and the equidistant material distribution arm 34 is set to d3, then d1 = d2 = d3 (as shown in FIG. Fig.17 ).

[0041] When performing the transfer operation of the male metal rear shell, the male metal rear shell is first transferred to the material transfer groove 51 through the material taking avoidance gap 22 by the equidistant material dividing arm 34, and then the equidistant material dividing arm 34 moves backward to perform the material taking operation of the male metal rear shell for the second time. At the same time, the male metal rear shell placed in the material transfer groove 51 is transferred to the placement groove 12 by the auxiliary transfer arm 35. In this way, the displacement path of the equidistant material dividing arm 34 is reduced to half of the original one, which doubles the working efficiency of the material handling unit 3.

[0042] It should be noted that, in this embodiment, the first power driving unit 32 for driving the equidistant material distributing arm 34 to perform a large-distance displacement movement along the front-to-back direction is preferably a screw linear module; and the second power driving unit 33 for driving the equidistant material distributing arm 34 to perform a small-distance displacement movement along the up-down direction is preferably a cylinder (such as Figure 8 , 9As shown in ). According to public information, the lead screw linear module has the advantages of high precision, long life, low noise, and smooth operation, and is particularly suitable for large distance occasions; while the cylinder has the advantages of simple structure, easy installation and maintenance, and low environmental requirements, and is particularly suitable for small distance occasions.

[0043] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A mating system suitable for a male end of a Type-C electrical connector, characterized in that: The invention comprises a front feeding line, a rear feeding line, a material handling unit and a material pushing unit; the front feeding line is used to convey the male metal front shell, and a front circulation channel for the circulation of the male metal front shell is provided on the front feeding line; a placement groove which is intersected with the front circulation channel is provided on the front feeding line, so as to place the male metal rear shell to be plugged in; the rear feeding line is arranged in parallel to the rear of the front feeding line, so as to convey the male metal rear shell, and a rear circulation channel for the circulation of the male metal rear shell is provided on the rear feeding line; a placement groove which is intersected with the rear circulation channel is provided on the rear feeding line The material handling unit simultaneously crosses the front material feeding line and the rear material feeding line to transfer the male metal rear shell to the placement groove through the material feeding avoidance gap; the material pushing unit is arranged directly behind the front material feeding line and is opposite to the placement groove; when the male metal rear shell is placed in the placement groove and the male metal front shell is parked in place relative to the placement groove, the material pushing unit is actuated to push the male metal rear shell to perform translational movement toward the male metal front shell until the male metal rear shell is plugged into the male metal front shell; The material handling unit includes a support frame, a first power drive unit, a second power drive unit and an equidistant material dividing arm; the first power drive unit and the second power drive unit are both supported by the support frame to respectively drive the equidistant material dividing arm to perform displacement movements along the front-to-back direction and the up-and-down direction; the equidistant material dividing arm includes a base plate, a tension plate, a material dividing block, a cylinder and a rear vacuum adsorption component; a material dividing cavity is provided on the base plate; the tension plate crosses the material dividing cavity and is directly driven by the cylinder; the number of the material dividing blocks is set to 4, which are built into the material dividing cavity and are all sleeved on the tension plate; along the length direction thereof, a limiting step is provided on the tension plate; the number of the limiting steps is consistent with the number of the material dividing blocks, and they are arranged at equal intervals, and the limit positions of the material dividing blocks are limited one by one; the number of the rear vacuum adsorption components is consistent with the number of the material dividing blocks, and they are fixed on the material dividing blocks one by one and detachably, so as to directly adsorb the male end metal rear shell.

2. The mating system for the male end of a Type-C electrical connector according to claim 1, characterized in that: It also includes a transfer platform; the transfer platform is arranged between the front feed line and the rear feed line, and is provided with a material transfer groove for placing the male metal back shell; the material handling unit also includes an auxiliary transfer arm; the auxiliary transfer arm is arranged directly in front of the equidistant material dividing arm to transfer the male metal back shell from the material transfer groove to the placement groove; assuming that the distance between the material transfer groove and the material collection avoidance gap is set to d1, the distance between the material transfer groove and the placement groove is set to d2, and the distance between the auxiliary transfer arm and the equidistant material dividing arm is set to d3, then d1=d2=d3.

3. The mating system for the male end of a Type-C electrical connector according to claim 2, characterized in that: The auxiliary transfer arm includes a mounting base plate and a front vacuum adsorption component; the number of the front vacuum adsorption components is set to be multiple, and all of them can be detachably fixed on the mounting base plate and are arranged at equal intervals.

4. The mating system for the male end of a Type-C electrical connector according to any one of claims 1 to 3, characterized in that: The pushing unit includes a third power driving part and a pushing assembly; the pushing assembly performs translational movement along the front-to-back direction under the action of the driving force of the third power driving part, and is composed of a plurality of pushing rods corresponding to the positions of the placement grooves one by one; a sliding groove for the pushing rod to pass through and communicating with the placement groove is provided on the front feeding line.

Images