![]() Method and apparatus for rewinding welding wire.
专利摘要:
公开号:NL2004285A 申请号:NL2004285 申请日:2010-02-23 公开日:2010-08-26 发明作者:Junichi Ono 申请人:Kobe Seiko Sho Kobe Steel Kk; IPC主号:
专利说明:
, METHOD AND APPARATUS FOR REWINDING WELDING WIRE BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for rewinding a welding wire fed from a bobbin that is set in a wire feeder onto a spool that is set in a wire winder, the rewinding being performed while the welding wire is traversed back and forth. 2. Description of the Related Art A welding-wire-rewinding apparatus rewinds a welding wire that is fed from a bobbin having a relatively large diameter onto a spool or the like having a relatively small diameter. Such a welding-wire-rewinding apparatus includes a wire feeder, a dancer roller device, a traverser, and a wire winder. A welding wire fed from a bobbin that is set in the wire feeder is threaded through the dancer roller device. The dancer roller device includes a fixed roller and a movable roller. The movable roller maintains the tension of the welding wire within a predetermined range by repeatedly moving toward and away from the fixed roller. The traverser traverses back and forth the welding wire whose tension is adjusted by the dancer roller device. The welding wire guided by the traverser is regularly wound onto a spool that is set in the wire winder. Known examples of the traverser used for winding a wire or the like include the following. An outline of a regular winding apparatus according to Japanese Unexamined Patent Application Publication No. 11-25775 including a traverser will now be described with reference to Figs. 2 and 3 showing a simplified plan view and a simplified side view, respectively, of the regular winding apparatus and Figs. 4A and 4B showing problems that have triggered the development of the regular winding apparatus. The regular winding apparatus is intended for preventing reduction in regular winding accuracy due to curls in a linear material. The regular winding apparatus includes a winding drum 52 onto which a linear material 51, such as an electric wire or a cable, is wound and a traverser 53 provided near the winding drum 52. The winding drum 52 is rotated about a rotational axis L thereof by a drive mechanism (not shown) including a motor and so forth. The traverser 53 includes an arm 56 extending from a traversing body and a roller 57 provided at the tip of the arm 56. The roller 57 has on the periphery thereof a groove by which the linear material 51 is received. The traverser 53 traverses back and forth in the directions of arrows a and b parallel to the rotational axis L of the winding drum 52. The linear material 51 received by the groove of the roller 57 is traversed back and forth with the traversing movement of the arm 56 in the directions of the arrows a and b. In other words, the linear material 51 fed to the winding drum 52 is traversed back and forth with the rotation of the winding drum 52, thereby being regularly wound onto the winding drum 52. A first guide 61 that forms a first bend 60 in a portion of the linear material 51 and a second guide 63 that forms a second bend 62 in a portion of the linear material 51 are provided immediately before the winding drum 52. The first and second guides 61 and 63 eliminate curls formed in upstream processes and the like. The first guide 61 includes a guide roller 64 provided on the arm 56 of the traverser 53 and forms the first bend 60 in a portion of the linear material 51. The first bend 60 has a center 0 thereof on a side of the linear material 51 remote from a preceding turn 67 in a roll 66 of the linear material 51 on the winding drum 52 and projects toward the preceding turn 67. The center 0 shown in Fig. 2 is the center of a circle containing an arc formed by the first bend 60 with a specific radius of curvature. That is, while the linear material 51 is wound from the side of one flange 70 toward the side of the other flange 71, the center O of the first bend 60 is defined on a side of the linear material 51 near the other flange 71 in plan view, and the first bend 60 is formed by the guide roller 64 with a portion of the linear material 51 that has just been wound and the roller 57 of the traverser 53 acting as supports. In short, the roller 57 and the guide roller 64 together form the first bend 60. Conversely, when the linear material 51 is wound from the side of the other flange 71 toward the side of the one flange 70, the center 0 of the first bend 60 needs to be changed to the other side by a regular-winding-direction changer so that the first bend 60 is formed symmetrically with the shape shown in Fig. 2. Therefore, the first guide 61 needs to be provided on, in plan view, a side of the linear material 51 remote from the roller 57. This means that another guide roller 65 shown by virtual lines in Fig. 2 needs to be provided. That is, the center 0 of the first bend 60 is defined on a side of the linear material 51 near the one flange 70 in plan view, whereby the first bend 60 is formed by the guide roller 65 with the portion of the linear material 51 that has just been wound and the roller 57 of the traverser 53 acting as supports. In short, the roller 57 and the guide roller 65 together form the first bend 60. The second guide 63 includes a guide roller 72 provided on the arm 56 and forms the second bend 62 in a portion of the linear material 51. The second bend 62 is formed in a plane containing a winding plane (a cross section of the winding drum 52 onto which the linear material 51 is currently being wound) and projects in a direction opposite to the direction of a bend in the linear material 51 in the winding plane. That is, the second bend 62 is formed by the guide roller 72 with the roller 57 of the traverser 53 acting as a support. In short, the roller 57 and the guide roller 72 together form the second bend 62. Thus, in the regular winding apparatus configured as described above, a curl projecting in a direction opposite to a curl shown in Fig. 4A is formed by the first guide 61, and a curl projecting in a direction opposite to a curl shown in Fig. 4B is formed by the second guide 63. In this manner, curls facilitating the winding of the linear material 51 onto the winding drum 52 are formed. This prevents, during winding, interference (contact) between the preceding turn 67 in the roll 66 on the winding drum 52 and a portion of the linear material 51 that is currently being wound up. Furthermore, the portion of the linear material 51 that is currently being wound is wound up closely to the preceding turn 67. An outline of a linear-material-winding apparatus according to Japanese Unexamined Patent Application Publication No. 2004-307104 will now be described. The linear-material-winding apparatus according to this known example is intended for realizing preferable lane change of a linear material (such as electric wire or any other wire or cable) to be wound onto a bobbin and for significantly improving the commercial value of the linear material. More specifically, the apparatus includes a traverser capable of traversing back and forth in an axial direction of the bobbin onto which the linear material is wound. The linear material is guided by a supply-side pulley and a feed-side pulley both provided on a sliding table of the traverser and is regularly wound onto the bobbin in a plurality of layers. The apparatus also includes control means (a control device) that controls the movement of the traverser in accordance with a wire incoming angle formed between a line orthogonal to the axis of the bobbin and the linear material fed from the traverser, the wire incoming angle being detected by incoming-angle-detecting means. It is not preferable, however, to apply the traverser of the regular winding apparatus or the linear-materialwinding apparatus according to the known examples to a wirewinding apparatus that winds onto a spool a thin, highly elastic welding wire having a diameter of, for example, about 1.2 to 1.6 mm. Problems in the techniques according to the known examples will now be described. In the regular winding apparatus according to Japanese Unexamined Patent Application Publication No. 11-25775, to prevent reduction in regular winding accuracy due to "curls" in the linear material, bends are formed in the linear material before the linear material is received by the roller that guides the linear material toward the winding drum, whereby the "curls" in the linear material formed in upstream processes and the like are to be eliminated. In a case where the linear material is a welding wire, however, irregular winding may occur if the wire is wound under no tension. Therefore, the welding wire needs to be wound under a certain tension such that the wire runs along a straight line shown as two-dot chain lines in Fig. 2. In such a case, since the welding wire is bent by the roller to the right and left alternately for every traversing movement of the traverser, the welding wire is guided by the roller with "curls". The problem in the regular winding apparatus according to Japanese Unexamined Patent Application Publication No. 11-25775 also occurs in the linear-material-winding apparatus according to Japanese Unexamined Patent Application Publication No. 2004-307104. Specifically, since the linear material is guided to the bobbin via the supply-side pulley (hereinafter pulleys are referred to as rollers) and the feed-side roller provided on the sliding table of the traverser, the linear material, i.e., a welding wire, under a certain tension is bent to the right and left alternately for every traversing movement of the traverser. Consequently, the welding wire has "curls". It is of course considered that the "curls" in the welding wire could be straightened if a roll straightener that straightens the welding wire in horizontal and vertical directions with respect to a direction in which the wire runs is provided on a side near the winding drum or the spool with respect to the roller on the sliding table (corresponding to a traversing table) included in the traverser. Nevertheless, it is difficult to completely eliminate the curls in the wire by such a roll straightener, and some curls remain. For example, when welding is performed, the tip of the welding wire fed from a torch is bent to the right and left alternately because of the "curls" formed as described above. Accordingly, the direction of arc changes toward the right and left alternately, making it difficult to perform welding. This is disadvantageous in maintaining the strengths of welded products and in the appearances of such products. Moreover, it is difficult to improve the efficiency of welding work (an extremely high level of welding technique is required). SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a method and apparatus for rewinding a welding wire in which "curls" in the welding wire are straightened efficiently and an appropriate cast is formed in the welding wire, whereby, during welding, swaying of the arc point and changes in the speed at which the welding wire is fed are suppressed, and welding is performed stably, resulting in advantages that the quality of the welding wire, including the strength of a welded product and the appearance of a welded part, is guaranteed, and that the efficiency of welding work is improved. To solve the problems described above, according to an aspect of the present invention, a welding-wire-rewinding method is provided in which a welding wire fed from a bobbin is continuously wound onto a spool having a diameter smaller than that of the bobbin with a dancer roller device interposed therebetween while the welding wire is traversed back and forth in an axial direction of the spool and is straightened by a traverser carrying a roll straightener. The method includes forming regular curls in the welding wire in a single direction by looping the welding wire continuously running from the dancer roller device, and guiding the welding wire into the roll straightener. According to another aspect of the present invention, a welding-wire-rewinding apparatus includes a wire feeder in which a bobbin is set; a dancer roller device including a fixed roller and a movable roller around which a fed welding wire is threaded, the dancer roller device being configured to maintain a tension of the welding wire within a predetermined range; a guide wheel device configured to loop the welding wire coming from the dancer roller device; a roll straightener configured to continuously straighten the looped welding wire; a traverser carrying the roll straightener and configured to traverse the welding wire back and forth in an axial direction of a spool; and a wire winder in which the spool onto which the welding wire fed from the traverser is continuously wound is set. In the welding-wire-rewinding method or the welding-wire-rewinding apparatus according to the above aspects of the present invention, regular curls are formed in the welding wire in a single direction by looping the welding wire continuously running from the dancer roller device. Then, the welding wire is guided into the roll straightener. Therefore, curls in the welding wire are straightened efficiently and an appropriate cast is formed in the welding wire. Consequently, the quality of the welding wire is guaranteed, and the efficiency of welding work is improved. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1A is a schematic plan view of a welding-wirerewinding apparatus according to an embodiment of the present invention for carrying out a welding-wire-rewinding method according to the present invention, and Fig. IB is a view seen in the direction of an arrow IB in Fig. 1A; Fig. 2 is a simplified plan view of a regular winding apparatus according to a known example; Fig. 3 is a simplified side view of the regular winding apparatus according to the known example; and Figs. 4A and 4B show problems that have triggered the development of the regular winding apparatus according to the known example. DESCRIPTION' OF THE PREFERRED EMBODIMENTS A welding-wire-rewinding apparatus according to an embodiment of the present invention for carrying out a welding-wire-rewinding method according to the present invention will now be described with reference to Fig. 1A, which is a schematic plan view of the welding-wire-rewinding apparatus, and Fig. IB, which is a view seen in the direction of an arrow IB in Fig. 1A. Figs. 1A and IB show a welding-wire-rewinding apparatus 1 according to an embodiment of the present invention. The welding-wire-rewinding apparatus 1 includes a wire feeder 2 and a dancer roller device 4. A bobbin 3 (rotatable about a horizontal axis) having a relatively large diameter and onto which a welding wire 9 is wound is set in the wire feeder 2. The welding wire 9 fed from the bobbin 3 is threaded through the dancer roller device 4. The dancer roller device 4 includes a fixed roller 4a and a movable roller 4b. The movable roller 4b maintains the tension of the welding wire 9 within a predetermined range by moving toward and away from the fixed roller 4a. The welding-wire-rewinding apparatus 1 also includes a guide wheel device 5, a traverser 6, a spool 8, and a wire winder 7. The guide wheel device 5 loops the welding wire 9 whose tension is adjusted by the dancer roller device 4 by 360° in plan view. The configuration of the guide wheel device 5 will be described separately below. The traverser 6 includes the following: a traversing table 6a that traverses back and forth in the directions represented by arrows L and R in Fig. 1A, i.e., parallel to the rotational axis of the spool 8; a roll straightener 6b that is provided on the traversing table 6a and continuously straightens the welding wire 9 looped by the guide wheel device 5; and a traversing roller 6c that guides the welding wire 9 straightened by the roll straightener 6b. The traverser 6, carrying the roll straightener 6b, traverses the welding wire 9 back and forth in the axial direction of the spool 8. The welding wire 9 straightened and guided by the traverser 6 as described above is regularly wound onto the spool 8 (rotatable about a horizontal axis) that is set in the wire winder 7. The guide wheel device 5 includes a first redirecting wheel 5a, a second redirecting wheel 5b, and a third redirecting wheel 5c. The first redirecting wheel 5a is rotatable about a vertical axis and changes the running direction of the welding wire 9 whose tension has been adjusted by the dancer roller device 4 toward the lower left in Fig. 1A with respect to the running direction thereof. The welding wire 9 redirected by the first redirecting wheel 5a is threaded around the second redirecting wheel 5b from a side near the wire winder 7, whereby the second redirecting wheel 5b redirects the welding wire 9 coming from the side of the dancer roller device 4 toward the side of the traverser 6. To prevent interference between lines of the welding wire 9 at the point where the lines cross, the rotational axis of the second redirecting wheel 5b is tilted toward the dancer roller device 4 such that the welding wire 9 redirected by the first redirecting wheel 5a is received at an upper position and is fed from a lower position. As described above, the second redirecting wheel 5b is set in such a manner as to receive the welding wire 9 at an upper position and feed the welding wire 9 from a lower position. Such a configuration, however, is not necessarily employed. For example, the second redirecting wheel 5b may conversely receive the welding wire 9 at a lower position and feed the welding wire 9 from an upper position. The welding wire 9 redirected by the second redirecting wheel 5b is threaded around the third redirecting wheel 5c rotatably attached to the tip of a vertical shaft projecting from an end of the traversing table 6a near the first redirecting wheel 5a. The welding wire 9 is thus redirected toward and guided into the roll straightener 6b. As can be understood well from the above description, the welding wire 9 running from the dancer roller device 4 is sequentially threaded around the first to third redirecting wheels 5a to 5c, thereby being looped by 360° in plan view. In the embodiment of the present invention, the first to third redirecting wheels 5a to 5c included in the guide wheel device 5 all redirect the welding wire 9 threaded therearound toward the left with respect to the running direction of the welding wire 9, thereby looping the welding wire 9 by 360°. The redirection, however, is not necessarily made toward the left. The welding wire 9 may alternatively be redirected toward the right with respect to the running direction thereof, thereby being looped by 360°. The behavior of the welding wire 9 in the above configuration will now be described. The welding wire 9 fed from the bobbin 3 enters the dancer roller device 4, in which the tension of the welding wire 9 is adjusted by the fixed roller 4a and the movable roller 4b, and is guided into the guide wheel device 5. The welding wire 9 that has been guided into the guide wheel device 5 runs sequentially around the first and second redirecting wheels 5a and 5b, and the third redirecting wheel 5c, which is provided on the traversing table 6a of the traverser 6, thereby being looped by 360° in plan view. The welding wire 9 that has come out of the third redirecting wheel 5c of the guide wheel device 5 further runs through the roll straightener 6b, which is also provided on the traversing table 6a, and the traversing roller 6c, and is continuously wound onto the spool 8 that is set in the wire winder 7. Thus, the welding wire 9 is rewound. In such a welding-wire-rewinding operation performed by the welding-wire-rewinding apparatus 1, the welding wire 9 that has been wound onto the spool 8 has regular "curls" because of the 360° looping of the welding wire 9 performed by the guide wheel device 5 including the first and second redirecting wheels 5a and 5b and the third redirecting wheel 5c provided on the traversing table 6a of the traverser 6, the looping being made toward the left with respect to the running direction of the welding wire 9. This means that the welding wire 9 is fed in a constant direction regardless of the traversing movement of the traverser 6. Consequently, when welding is performed with the welding wire 9 that has been rewound in accordance with the embodiment of the present invention, the tip of the welding wire 9 fed from a torch constantly curls in a single direction, i.e., to the left. Thus, according to the embodiment of the present invention, "curls" in a welding wire is straightened efficiently, and an appropriate cast is formed in the welding wire. Therefore, during welding, swaying of the arc point and changes in the speed at which the welding wire is fed are suppressed, and stable welding is performed. Consequently, the quality of the welding wire, including the strength of a welded product and the appearance of a welded part, is guaranteed. Moreover, compared with the cases of the welding wires that have been rewound by the apparatuses according to the known examples and therefore have irregular "curls" bending to the right and left alternately, welding work can be performed more easily, and the efficiency of the welding work is therefore improved. The welding-wire-rewinding apparatus 1 according to the embodiment described above is only an example of the present invention. Design changes and the like can be freely made to the embodiment without departing from the technical scope of the present invention. That is, the present invention is not limited to the configuration according to the embodiment described above. For example, while the above description concerns an embodiment in which a flux-cored welding wire is rewound, the present invention may also be applied to cases in which other kinds of welding wires, including a solid welding wire, are rewound. To summarize, according to the present invention, "curls" in a welding wire can be straightened efficiently, and the welding wire wound onto a bobbin having a relatively large diameter can be rewound efficiently around a spool having a relatively small diameter by forming an appropriate cast in the welding wire. Thus, the quality of the welding wire is guaranteed, and the efficiency of welding work is improved. Therefore, the present invention is suitable for an apparatus and method for rewinding a welding wire manufactured in a highly efficient manufacturing line in which, for example, a flux-cored welding wire is manufactured through the steps of forming a U-shaped hoop (steel strip) by unwinding a coiled hoop, filling flux into the hoop during the formation of the U-shaped hoop, and drawing and rewinding the flux-filled wire having a tubular shape, the steps being performed continuously in a single manufacturing line.
权利要求:
Claims (2) [1] A method for rewinding a welding wire in which a welding wire supplied from a reel is continuously wound onto a spool having a smaller diameter than the reel, with a dance roller device interposed therebetween, while the welding wire through a roller direction device carrying a traverser device in a the axial direction of the coil is traversed to and fro and straightened, comprising the method: regular curls form in the welding wire in one and the same direction by having the welding wire running continuously from the dance rolling device looped; and the welding wire lead into the rolling direction device. [2] A rewinding device for welding wire comprising: a welding wire supply device in which a reel is placed; a dance roll device comprising a fixed roll and a movable roll around which a supplied welding wire is passed, the dance roll device being arranged to keep a tension of the welding wire within a predetermined range; a guide wheel device adapted to cause the welding wire from the dance roller device to pass through a loop; a rolling aiming device adapted to continuously straighten the looped welding wire; a traversing device carrying the rolling direction device and adapted to traverse the welding wire back and forth in an axial direction of a coil; and a wire winder in which the coil is placed, on which the welding wire supplied from the traversing device is continuously wound.
类似技术:
公开号 | 公开日 | 专利标题 NL2004285C2|2011-11-23|Method and apparatus for rewinding welding wire. KR101500597B1|2015-03-09|Spun yarn winding device and spun yarn winding facility EP2612834B1|2018-08-01|Slack preventing device for wire rod wound around spool, and slack preventing method therefore CN101454850B|2011-08-31|Wire winding system, tension device, and wire winding method JP4058703B1|2008-03-12|Method and apparatus for manufacturing annular concentric stranded bead cord US20060266794A1|2006-11-30|Method and apparatus for packaging wire in a wire container CA2842252C|2017-03-28|Flexible tube, manufacturing method and apparatus EP1947046B1|2010-03-24|Yarn winding device US4202512A|1980-05-13|Level layer winding method and apparatus US5377931A|1995-01-03|Apparatus for reeling a wound web reel US20170088389A1|2017-03-30|Winding device for strand-like material to be wound JP5876158B2|2016-03-02|Device comprising a rotating arm for unwinding a strand of material US6000656A|1999-12-14|Space saving wire drawing machine with floor mounted wire coil EP0916418A2|1999-05-19|Multipass wiredrawing machine provided with a device for improved adjustment and control of the tension of the wire being processed, particularly for drawing metal wires US5390482A|1995-02-21|Apparatus and method for sending out linear material JP2005280941A|2005-10-13|Wire winding device JP4873622B2|2012-02-08|Wire rod winding device and feeding device JP2011161660A|2011-08-25|Tire molding machine KR100405906B1|2003-11-14|Apparatus for suppressing strip tension hunting in horizontal looper SU848398A1|1981-07-23|Device for bundling coils on coiler drum SU1142399A1|1985-02-28|Device for rewinding wound thread-like material from long-size article to reel JP2000301234A|2000-10-31|Method and equipment for coiling JP2006315236A|2006-11-24|Method and apparatus for producing bead for pneumatic tire KR20010002548A|2001-01-15|Steel cord twister having a sub-wheel RU30347U1|2003-06-27|Wire Winder Stacker
同族专利:
公开号 | 公开日 CN101811631B|2013-05-22| KR20100097061A|2010-09-02| NL2004285C2|2011-11-23| JP2010194576A|2010-09-09| CN101811631A|2010-08-25|
引用文献:
公开号 | 申请日 | 公开日 | 申请人 | 专利标题 DE3106947A1|1980-03-01|1982-04-15|Barmag Barmer Maschinenfabrik Ag, 5630 Remscheid|Winding apparatus for winding up flat threads to form cylindrical cross-wound bobbins|CN102060212A|2010-11-16|2011-05-18|正裕电器配件有限公司|Tension adjusting device| FI124236B|2010-12-01|2014-05-15|Kemppi Oy|Arrangement in a wire feed device of a welding assembly and method for rolling out welding wire| CN102527883B|2012-03-27|2014-07-09|张家港市胜达钢绳有限公司|Rewinding straightening device for tire bead steel wires| CN102616606A|2012-04-06|2012-08-01|柳州市红日焊丝制造有限公司|Layer winding device for welding wire| CN102764830B|2012-07-12|2015-04-22|安徽安泽电工有限公司|Fully-automatic computerized winding machine| KR101914566B1|2012-07-27|2018-11-02|삼성에스디아이 주식회사|Winding apparatus for manufacturing electrode assembly and control method thereof| CN102962271B|2012-12-12|2015-04-08|河南恒星科技股份有限公司|Wire winding and straightening mechanism of water tank wire-drawing machine| CN104418158A|2013-08-30|2015-03-18|江苏中江焊丝有限公司|Device for precision winding of welding wire| JP6109064B2|2013-12-27|2017-04-05|株式会社神戸製鋼所|Straightening device for welding wire| JP6316605B2|2014-01-27|2018-04-25|株式会社ダイヘン|Feed mechanism, arc system| JP6279913B2|2014-01-27|2018-02-14|株式会社ダイヘン|Feed mechanism, arc system| US9950385B2|2014-01-27|2018-04-24|Daihen Corporation|Wire feeding mechanism and arc processing system employing the same| CN104376927B|2014-11-30|2017-06-09|浙江德清浙北线缆有限公司|A kind of continuous thread guide devices| CN105836528A|2016-05-18|2016-08-10|杭州响尾蛇科技有限公司|Constant moment servo tensioner| CN106395495A|2016-06-27|2017-02-15|温州集智科技有限公司|Power cable fixed-length conveying, cutting and storing device| WO2019207827A1|2018-04-26|2019-10-31|三菱電機株式会社|Tension adjusting device and wire winding device| KR102160074B1|2018-08-30|2020-09-25|이티에스|Wire handler| KR102160073B1|2018-08-30|2020-09-25|이티에스|Wire handler| CN109335850B|2018-11-28|2021-08-06|重庆智荟数创科技有限公司|Coiling mechanism for gold bonding wire| CN111498593B|2020-04-17|2021-12-28|中船黄埔文冲船舶有限公司|Cable feeding device and cable feeding method for ship steel wire rope winch| CN111874739B|2020-08-05|2022-03-08|大连银路电控设备有限公司|Full-automatic coiling baling press| CN113716394B|2021-11-04|2022-03-08|常州市海宝焊割有限公司|Full-automatic welding wire winding machine with guide mechanism|
法律状态:
优先权:
[返回顶部]
申请号 | 申请日 | 专利标题 JP2009042035A|JP2010194576A|2009-02-25|2009-02-25|Method and apparatus for rewinding welding wire| JP2009042035|2009-02-25| 相关专利
Sulfonates, polymers, resist compositions and patterning process
Washing machine
Washing machine
Device for fixture finishing and tension adjusting of membrane
Structure for Equipping Band in a Plane Cathode Ray Tube
Process for preparation of 7 alpha-carboxyl 9, 11-epoxy steroids and intermediates useful therein an
国家/地区
|