阅读说明：本技术 一种自适应式压接装置 (Self-adaptive crimping device ) 是由 宾兴 李明星 李太松 于 2019-10-29 设计创作，主要内容包括：本发明公开了一种自适应式压接装置,包括连接部分及压接部分,其中,上述连接部分与压接机的驱动机构连接,经驱动机构驱动直线运动、升降运动及旋转运动；上述压接部分设置于连接部分的下方,并与连接部分间隔设置,压接部分下部可拆卸连接有压接头；压接部分与连接部分之间的间隙空间内设置有自适应球体及柔性连接板,自适应球体可转动地连接在柔性连接板与连接部分之间的间隙或柔性连接板与压接部分之间的间隙中,压接部分下压PCB板上的连接器,连接器受压平面的反作用力使柔性连接板自适应调整至与受压平面平行的方向。本发明实现压接面自适应平行贴合及压接头自动拆装。(The invention discloses a self-adaptive crimping device, which comprises a connecting part and a crimping part, wherein the connecting part is connected with a driving mechanism of a crimping machine and is driven to do linear motion, lifting motion and rotary motion by the driving mechanism; the crimping part is arranged below the connecting part and is arranged at an interval with the connecting part, and the lower part of the crimping part is detachably connected with a crimping head; the self-adaptive ball body and the flexible connecting plate are arranged in a gap space between the crimping part and the connecting part, the self-adaptive ball body is rotatably connected in a gap between the flexible connecting plate and the connecting part or a gap between the flexible connecting plate and the crimping part, the crimping part presses down the connector on the PCB, and the reaction force of a compression plane of the connector enables the flexible connecting plate to be self-adaptively adjusted to the direction parallel to the compression plane. The invention realizes the self-adaptive parallel bonding of the compression joint surface and the automatic disassembly and assembly of the compression joint head.)

1. An adaptive crimping device characterized in that: the device comprises a connecting part (614) and a crimping part (615), wherein the connecting part (614) is connected with a driving mechanism of a crimping machine and is driven to move linearly, lift and rotate by the driving mechanism; the crimping part (615) is arranged below the connecting part (614) and is arranged at a distance from the connecting part (614), and a crimping head (61510) is detachably connected to the lower part of the crimping part (6145); a self-adaptive ball body (6146) and a flexible connecting plate (6145) are arranged in a gap space between the crimping part (615) and the connecting part (614), the self-adaptive ball body (6146) is rotatably connected in a gap between the flexible connecting plate (6145) and the connecting part (614) or a gap between the flexible connecting plate (6145) and the crimping part (615), the crimping part (6145) presses down a connector on the PCB, and the flexible connecting plate (6145) is self-adaptively adjusted to the direction parallel to a pressed plane by the reaction force of the pressed plane of the connector.

2. The crimping machine as claimed in claim 1, wherein: the connecting part (614) also comprises a connecting seat (6141), a driving wheel (6142) and a fulcrum (6143), wherein the fulcrum (6143) is rotatably inserted on the connecting seat (6141) and extends downwards; the driving wheel (6142) is sleeved and fixed on the fulcrum shaft (6143), the driving wheel (6142) is connected with a driving belt of a driving mechanism of the crimping machine, and the driving belt drives the driving wheel (6142) and the fulcrum shaft (6143) to rotate.

3. The crimping surface self-adaptive crimping machine as claimed in claim 2, wherein: the connecting part (614) also comprises a pressing seat (6144) and a first spring (6149); wherein, the pressure seat (6144) is connected with the lower end of the fulcrum shaft (6143), and a first spring groove with an open bottom is arranged in the pressure seat (6144); the first spring (6149) is vertically inserted in the first spring groove.

4. The crimping surface self-adaptive crimping machine as claimed in claim 3, wherein: the connecting part (614) further comprises an adjusting seat (6147), an upper seat body (6148), a lower seat body (61410) and a connecting screw rod (61411), wherein the adjusting seat (6147) is arranged at the lower part of the pressing seat (6144) and is connected with a first spring (6149); the upper seat body (6148) is arranged in the middle of the adjusting seat (6147), and the lower part of the upper seat body (6148) is provided with an arc groove body with a downward opening; the lower seat body (61410) is arranged below the upper seat body (6148) at intervals, the flexible connecting plate (6145) is positioned in a gap between the upper seat body (6148) and the lower seat body (61410), and the upper part of the lower seat body (61410) is provided with an arc-shaped groove body with an upward opening.

5. The crimping surface self-adaptive crimping machine according to claim 4, wherein: the self-adaptive sphere (6146) is arranged in the arc-shaped grooves of the upper seat body (6148) and the lower seat body (61410) and rotates freely; the connecting screw rods (61411) comprise at least two connecting screw rods (61411), and the connecting screw rods are connected between the adjusting seat (6147) and the flexible connecting plate (6145) and between the flexible connecting plate (6145) and the crimping part (615).

6. The crimping surface self-adaptive crimping machine as claimed in claim 5, wherein: the crimping part (615) comprises a crimping seat (6151), a second spring (6153), a clamping sleeve (6154) and a limiting sleeve (6159), wherein the crimping seat (6151) is connected with the flexible connecting plate (6145) through a connecting screw (61411), and the lower seat body (61410) is arranged at the upper part of the crimping seat (6151); at least two second spring grooves (6152) with downward openings are arranged in the pressure joint seat (6151); the second spring (6153) comprises at least two, and the second spring slot (6153) is vertically arranged in the second spring slot (6152).

7. The crimping machine as claimed in claim 6, wherein: the clamping sleeve (6154) is slidably inserted into the second spring groove (6152), the upper part of the clamping sleeve (6154) is connected with the second spring (6152), an inclined pressing surface (6155) is arranged on the inner side wall of the lower part of the clamping sleeve (6154), and the inclined pressing surface (6155) gradually extends downwards from inside to outside.

8. The crimping surface self-adaptive crimping machine as claimed in claim 7, wherein: the limiting sleeve (6159) is arranged in the second spring groove (6152) and is close to the lower part, and the upper part of the limiting sleeve (6159) props against the clamping sleeve (6154) to prevent the clamping sleeve (6154) from sliding out of the second spring groove (6152) downwards.

9. The crimping surface self-adaptive crimping machine as claimed in claim 8, wherein: the crimping part (615) further comprises at least two ball clamping grooves (6156), ball clamping grooves (6157), a push sleeve (6158) and a clamping groove (61511), wherein the ball clamping grooves (6157) are formed in the side wall of the lower portion of the crimping seat (6151) and penetrate through the crimping seat (6151) from inside to outside; the number of the ball clamping grooves (6156) is at least two, and the ball clamping grooves (6157) are movably arranged in the ball clamping grooves (6156).

10. The crimping surface self-adaptive crimping machine as claimed in claim 9, wherein: the push sleeve (6158) is sleeved outside the clamping sleeve (6154), and the push sleeve (6158) is stressed to drive the clamping sleeve (6154) to move upwards to overcome the elastic force of the second spring (6153) so that the clamping ball (6156) slides outwards; the clamping groove (61511) is an annular groove body, the clamping groove (61511) is arranged on the outer side wall of the pressing joint (61510), and when the clamping sleeve (6154) descends, the clamping ball (6156) is pressed into the clamping groove (61511) by the inclined pressing surface (6155) so as to be connected with the pressing joint (61510).

Technical Field

The invention relates to the field of automation, in particular to a self-adaptive crimping device.

Background

The connector is a very common electronic component and is often used for being inserted on a PCB, the bottom of the connector is provided with two rows of metal pins which are designed side by side, and the metal pins are inserted into correspondingly designed pin holes on the PCB to realize electric conduction; the assembly of the connector is a production work with high precision requirement and great process difficulty; at present, the following technical difficulties in the connector assembly process need to be broken through: 1. in the connector assembling process, generally need through the dedicated crimping head of connector design to the difference, impress the connector in the pinhole of PCB board through the crimping head, because be face contact between crimping head and the connector stitch at the crimping in-process, the position depth of impressing of crimping head elder generation contact stitch is greater than the position of back contact stitch when plane nonparallel between them, stitch kneeling needle condition very easily appears in this kind of condition, leads to the crimping inefficacy, the defective products appears.

Disclosure of Invention

The invention aims to solve the technical problem of the prior art and provides a self-adaptive crimping device which adopts a self-adaptive ball body, a flexible connecting plate and a spring to connect and cooperate with each other to realize self-adaptive parallel lamination of crimping surfaces and greatly improve the crimping yield.

The technical scheme adopted by the invention is as follows: a self-adaptive crimping device comprises a connecting part and a crimping part, wherein the connecting part is connected with a driving mechanism of a crimping machine and is driven to move linearly, lift and rotate by the driving mechanism; the crimping part is arranged below the connecting part and is arranged at an interval with the connecting part, and the lower part of the crimping part is detachably connected with a crimping head; the self-adaptive ball body and the flexible connecting plate are arranged in a gap space between the crimping part and the connecting part, the self-adaptive ball body is rotatably connected in a gap between the flexible connecting plate and the connecting part or a gap between the flexible connecting plate and the crimping part, the crimping part presses down the connector on the PCB, and the reaction force of a compression plane of the connector enables the flexible connecting plate to be self-adaptively adjusted to the direction parallel to the compression plane.

Preferably, the connecting part further comprises a connecting seat, a driving wheel and a fulcrum, wherein the fulcrum is rotatably inserted on the connecting seat and extends downwards; the transmission wheel is sleeved and fixed on the support shaft and is connected with a transmission belt of a driving mechanism of the crimping machine, and the transmission belt drives the transmission wheel and the support shaft to rotate.

Preferably, the connecting part further comprises a pressing seat and a first spring; wherein, the pressure seat is connected with the lower end of the fulcrum shaft, and a first spring groove with an open bottom is arranged in the pressure seat; the first spring is vertically inserted in the first spring groove.

Preferably, the connecting part further comprises an adjusting seat, an upper seat body, a lower seat body and a connecting screw rod, wherein the adjusting seat is arranged at the lower part of the pressing seat and is connected with the first spring; the upper seat body is arranged in the middle of the adjusting seat, and the lower part of the upper seat body is provided with an arc groove body with a downward opening; the lower seat body is arranged below the upper seat body at intervals, the flexible connecting plate is positioned in a gap between the upper seat body and the lower seat body, and the upper part of the lower seat body is provided with an arc-shaped groove body with an upward opening.

Preferably, the adaptive sphere is arranged in the arc-shaped groove bodies of the upper seat body and the lower seat body and can rotate freely; the connecting screw rods comprise at least two connecting screw rods, and the connecting screw rods are connected between the adjusting seat and the flexible connecting plate and between the flexible connecting plate and the crimping part.

Preferably, the crimping part comprises a crimping seat, a second spring, a clamping sleeve and a limiting sleeve, wherein the crimping seat is connected with the flexible connecting plate through a connecting screw rod, and the lower seat body is arranged at the upper part of the crimping seat; at least two second spring grooves with downward openings are arranged in the crimping seat; the second spring comprises at least two springs, and the second spring groove is vertically arranged in the second spring groove.

Preferably, the cutting ferrule is slidably inserted in the second spring groove, the upper portion of the cutting ferrule is connected with the second spring, an inclined pressing surface is arranged on the inner side wall of the lower portion of the cutting ferrule, and the inclined pressing surface gradually extends downwards from inside to outside.

Preferably, the limiting sleeve is arranged in the second spring groove and close to the lower part, and the upper part of the limiting sleeve props against the clamping sleeve to prevent the clamping sleeve from sliding out of the second spring groove downwards.

Preferably, the crimping part further comprises at least two ball clamping grooves, a ball clamping groove, a push sleeve and a clamping groove, wherein the ball clamping grooves are formed in the side wall of the lower portion of the crimping seat and penetrate through the crimping seat from inside to outside; the ball clamping grooves are at least two, and the ball clamping grooves are movably arranged in the ball clamping grooves.

Preferably, the push sleeve is sleeved outside the clamping sleeve, and the push sleeve is stressed to drive the clamping sleeve to move upwards to overcome the elastic force of the second spring, so that the clamping ball slides outwards; above-mentioned draw-in groove is cyclic annular cell body, and the draw-in groove sets up on the lateral wall of crimping head, and when the cutting ferrule descends, the oblique pressure face inwards will block the ball draw-in groove of impressing to connect the crimping head.

The invention has the beneficial effects that:

aiming at the defects and shortcomings in the prior art, the invention independently develops and designs the self-adaptive crimping device which adopts the mutual cooperation of the self-adaptive ball, the flexible connecting plate and the spring connection to realize the self-adaptive parallel lamination of the crimping surface and greatly improves the crimping yield; the invention mainly solves the technical problem that when a crimping head presses down a connector, the pressed angles and pressed time of different pins of the connector are different, and the crimping fails because the pressed angle and pressed time of the different pins of the connector are different after a PCB moves in place due to the influence of factors in the actual crimping process such as installation errors, movement errors and the like and the non-parallel overlapping condition exists between the pressed surface of a pre-inserted connector on the PCB and the crimping surface of the crimping head. In view of the above technical problems to be solved, the present invention is originally designed on the basis of the conventional crimping machine. Particularly, the support shaft is rotatably arranged below the connecting seat and serves as a bearing structure, the driving wheel sleeved outside the support shaft is connected with the driving belt, and the driving belt drives the driving wheel and the support shaft to integrally rotate so as to adjust the crimping angle; meanwhile, the pressure seat is used as a supporting structure, the first spring groove with a downward opening is vertically arranged in the pressure seat, the first spring is vertically arranged in the first spring groove, the lower part of the first spring is connected with the adjusting seat, and the flexible connection of the adjusting seat is realized by utilizing the characteristic of the first spring, so that the angle of the plane where the adjusting seat is located can be adjusted in real time; flexible connecting plates are arranged below the adjusting seat at intervals, an upper seat body and a lower seat body are respectively arranged on the upper side and the lower side of each flexible connecting plate, arc-shaped groove bodies are correspondingly arranged on the upper seat body and the lower seat body, and the self-adaptive ball bodies are arranged in the two arc-shaped groove bodies and rotate freely; in the crimping process, after the crimping head receives upward reaction force of the connector, the reaction force acts on the flexible connecting plate, so that the flexible circuit board is adjusted to be parallel to the compression platform, and meanwhile, the self-adaptive ball body synchronously rotates along with the plane adjustment of the flexible circuit board; this kind of structural function along with the different automatic adaptation of crimping condition carries out the plane adjustment has guaranteed crimping angle and the crimping time point uniformity of each stitch of connector when crimping effectively, has greatly promoted the crimping quality. In addition, the lower part of the connecting part is provided with the crimping part, a plurality of second spring grooves are vertically arranged in the crimping seat of the crimping part, second springs are arranged in the second spring grooves, the lower parts of the second springs are inserted with the clamping sleeves and extend to the lower parts of the second spring grooves, the inner side walls of the lower parts of the second springs are provided with inclined pressing surfaces which gradually incline outwards from top to bottom, the second spring grooves below the clamping sleeves are internally provided with limiting sleeves, and the limiting sleeves are fixedly arranged so as to abut against the limiting clamping sleeves and prevent the clamping sleeves from sliding out downwards; meanwhile, the side wall of the lower part of the crimping seat is provided with a ball clamping groove, and a ball is movably arranged in the ball clamping groove; correspondingly, the outer side wall of the upper part of the crimping head is provided with an inward concave clamping groove; when the crimping head is inserted into the crimping seat from bottom to top, the clamping sleeve slides downwards under the action of the elastic force of the second spring, and the inclined pressing surface presses inwards to force the clamping ball to slide into the clamping groove of the crimping head, so that the crimping head is detachably connected; when the crimping head needs to be replaced, an upward acting force acts on the clamping sleeve, so that the clamping sleeve overcomes the elastic force of the second spring and slides upwards, the inclined pressing surface gradually leaves the clamping ball, the clamping ball slides out of the clamping groove, and the crimping head is in a movable state and can be flexibly detached from the crimping seat; through this kind of sliding press-in snap-fit structure function, the efficiency of crimping head replacement is greatly promoted.

Drawings

Fig. 1 is a schematic perspective view of the present invention.

Fig. 2 is a schematic view of a hidden structure of the component of the present invention.

FIG. 3 is a second schematic view of the hidden structure of the present invention.

Fig. 4 is a front view of the present invention.

Fig. 5 is a sectional view of section a-a in fig. 4.

Fig. 6 is a front view of the crimping portion of the present invention.

Fig. 7 is a sectional view of section B-B in fig. 6.

Detailed Description

The invention will be further described with reference to the accompanying drawings in which:

as shown in fig. 1 to 7, the technical solution adopted by the present invention is as follows: an adaptive crimping device comprises a connecting part 614 and a crimping part 615, wherein the connecting part 614 is connected with a driving mechanism of a crimping machine, and is driven to move linearly, lift and rotate by the driving mechanism; the above-mentioned crimping portion 615 is provided below the connecting portion 614 and is provided at a distance from the connecting portion 614, and a crimping head 61510 is detachably attached to a lower portion of the crimping portion 6145; a self-adaptive sphere 6146 and a flexible connecting plate 6145 are arranged in a gap space between the crimping part 615 and the connecting part 614, the self-adaptive sphere 6146 is rotatably connected in a gap between the flexible connecting plate 6145 and the connecting part 614 or a gap between the flexible connecting plate 6145 and the crimping part 615, the crimping part 6145 presses down a connector on the PCB, and the flexible connecting plate 6145 is self-adaptively adjusted to be parallel to a pressed plane by the reaction force of the pressed plane of the connector.

The connecting portion 614 further includes a connecting base 6141, a driving wheel 6142 and a support shaft 6143, wherein the support shaft 6143 is rotatably inserted into the connecting base 6141 and extends downward; the driving wheel 6142 is sleeved and fixed on the support shaft 6143, the driving wheel 6142 is connected with a driving belt of a driving mechanism of the crimping machine, and the driving belt drives the driving wheel 6142 and the support shaft 6143 to rotate.

The connecting portion 614 further comprises a pressing seat 6144 and a first spring 6149; wherein, the pressing base 6144 is connected to the lower end of the fulcrum 6143, and a first spring groove with an open bottom is arranged in the pressing base 6144; the first spring 6149 is vertically inserted into the first spring slot.

The connecting portion 614 further includes an adjusting seat 6147, an upper seat 6148, a lower seat 61410 and a connecting screw 61411, wherein the adjusting seat 6147 is disposed at the lower portion of the pressing seat 6144 and connected to the first spring 6149; the upper seat body 6148 is arranged in the middle of the adjusting seat 6147, and the lower part of the upper seat body 6148 is provided with an arc groove body with a downward opening; the lower seat body 61410 is arranged below the upper seat body 6148 at intervals, the flexible connecting plate 6145 is positioned in a gap between the upper seat body 6148 and the lower seat body 61410, and the upper part of the lower seat body 61410 is provided with an arc-shaped groove body with an upward opening.

The adaptive sphere 6146 is arranged in the arc-shaped groove of the upper seat body 6148 and the lower seat body 61410 and rotates freely; the connecting screw 61411 comprises at least two connecting screws 61411, and the connecting screws 61411 are connected between the adjusting seat 6147 and the flexible connecting plate 6145 and between the flexible connecting plate 6145 and the crimping part 615.

The crimping part 615 includes a crimping seat 6151, a second spring 6153, a clamping sleeve 6154 and a stop sleeve 6159, wherein the crimping seat 6151 is connected with the flexible connecting plate 6145 through a connecting screw 61411, and the lower seat body 61410 is arranged at the upper part of the crimping seat 6151; at least two second spring slots 6152 with downward openings are arranged in the pressure connecting seat 6151; the second spring 6153 includes at least two, and the second spring slot 6153 is vertically disposed in the second spring slot 6152.

The cutting sleeve 6154 is slidably inserted into the second spring groove 6152, the upper part of the cutting sleeve 6154 is connected with the second spring 6152, an inclined pressing surface 6155 is arranged on the inner side wall of the lower part of the cutting sleeve 6154, and the inclined pressing surface 6155 gradually extends downwards from inside to outside.

The position-limiting sleeve 6159 is disposed in the second spring slot 6152 and close to the lower portion, the upper portion of the position-limiting sleeve 6159 abuts against the cutting sleeve 6154, and the cutting sleeve 6154 is prevented from sliding out of the second spring slot 6152 downward.

The crimping part 615 further includes at least two ball clamping grooves 6156, ball clamping grooves 6157, push sleeves 6158 and clamping grooves 61511, wherein the ball clamping grooves 6157 are formed in the side wall of the lower portion of the crimping seat 6151, and the ball clamping grooves 6157 penetrate through the crimping seat 6151 from inside to outside; the ball clamping grooves 6157 are movably disposed in the ball clamping grooves 6156.

The push sleeve 6158 is sleeved outside the sleeve 6154, and the push sleeve 6158 is stressed to drive the sleeve 6154 to move upwards against the elastic force of the second spring 6153, so that the clamping ball 6156 slides outwards; the clamping groove 61511 is an annular groove body, the clamping groove 61511 is arranged on the outer side wall of the pressure welding head 61510, and when the clamping sleeve 6154 descends, the inclined pressing surface 6155 presses the clamping ball 6156 into the clamping groove 61511 so as to be connected with the pressure welding head 61510.

Furthermore, the invention designs a self-adaptive crimping device which adopts the mutual cooperation of a self-adaptive ball body, a flexible connecting plate and a spring to realize self-adaptive parallel lamination of crimping surfaces and greatly improves the crimping yield; the invention mainly solves the technical problem that when a crimping head presses down a connector, the pressed angles and pressed time of different pins of the connector are different, and the crimping fails because the pressed angle and pressed time of the different pins of the connector are different after a PCB moves in place due to the influence of factors in the actual crimping process such as installation errors, movement errors and the like and the non-parallel overlapping condition exists between the pressed surface of a pre-inserted connector on the PCB and the crimping surface of the crimping head. In view of the above technical problems to be solved, the present invention is originally designed on the basis of the conventional crimping machine. Particularly, the support shaft is rotatably arranged below the connecting seat and serves as a bearing structure, the driving wheel sleeved outside the support shaft is connected with the driving belt, and the driving belt drives the driving wheel and the support shaft to integrally rotate so as to adjust the crimping angle; meanwhile, the pressure seat is used as a supporting structure, the first spring groove with a downward opening is vertically arranged in the pressure seat, the first spring is vertically arranged in the first spring groove, the lower part of the first spring is connected with the adjusting seat, and the flexible connection of the adjusting seat is realized by utilizing the characteristic of the first spring, so that the angle of the plane where the adjusting seat is located can be adjusted in real time; flexible connecting plates are arranged below the adjusting seat at intervals, an upper seat body and a lower seat body are respectively arranged on the upper side and the lower side of each flexible connecting plate, arc-shaped groove bodies are correspondingly arranged on the upper seat body and the lower seat body, and the self-adaptive ball bodies are arranged in the two arc-shaped groove bodies and rotate freely; in the crimping process, after the crimping head receives upward reaction force of the connector, the reaction force acts on the flexible connecting plate, so that the flexible circuit board is adjusted to be parallel to the compression platform, and meanwhile, the self-adaptive ball body synchronously rotates along with the plane adjustment of the flexible circuit board; this kind of structural function along with the different automatic adaptation of crimping condition carries out the plane adjustment has guaranteed crimping angle and the crimping time point uniformity of each stitch of connector when crimping effectively, has greatly promoted the crimping quality. In addition, the lower part of the connecting part is provided with the crimping part, a plurality of second spring grooves are vertically arranged in the crimping seat of the crimping part, second springs are arranged in the second spring grooves, the lower parts of the second springs are inserted with the clamping sleeves and extend to the lower parts of the second spring grooves, the inner side walls of the lower parts of the second springs are provided with inclined pressing surfaces which gradually incline outwards from top to bottom, the second spring grooves below the clamping sleeves are internally provided with limiting sleeves, and the limiting sleeves are fixedly arranged so as to abut against the limiting clamping sleeves and prevent the clamping sleeves from sliding out downwards; meanwhile, the side wall of the lower part of the crimping seat is provided with a ball clamping groove, and a ball is movably arranged in the ball clamping groove; correspondingly, the outer side wall of the upper part of the crimping head is provided with an inward concave clamping groove; when the crimping head is inserted into the crimping seat from bottom to top, the clamping sleeve slides downwards under the action of the elastic force of the second spring, and the inclined pressing surface presses inwards to force the clamping ball to slide into the clamping groove of the crimping head, so that the crimping head is detachably connected; when the crimping head needs to be replaced, an upward acting force acts on the clamping sleeve, so that the clamping sleeve overcomes the elastic force of the second spring and slides upwards, the inclined pressing surface gradually leaves the clamping ball, the clamping ball slides out of the clamping groove, and the crimping head is in a movable state and can be flexibly detached from the crimping seat; through this kind of sliding press-in snap-fit structure function, the efficiency of crimping head replacement is greatly promoted.

The embodiments of the present invention are merely illustrative of specific embodiments thereof, and are not intended to limit the scope thereof. Since the present invention can be modified by a person skilled in the art, the present invention is not limited to the embodiments described above.