Abstract:
The invention relates to a method for producing battery terminals comprising different steps, during which a continuous wire ( 18 ) is cut ( 22 ) into predefined lengths, and then a pin head and point are formed. To this end, a conveyor path ( 40 ) is used, at the end of which the pegs ( 10 ) fall into a receptacle. In order to accelerate and simplify finishing of the pointed pins ( 10″ ), the aftertreatment of the pin points takes place on the conveyor path ( 40 ), between the sharpening stage ( 23 ) and the collecting receptacle ( 70 ), during which unwanted burrs can be removed on another cylinder ( 60 ). As a result, already finished pins fall into the receptacle at the end of the conveyor path.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates first of all to a method for producing pins, for example, battery terminals, as used in electrical batteries as an anode charge eliminator as well as to a device for performing the method. 
     2. Description of Related Art 
     The known methods start with a wire which is first cut into sections, then provided with a head, and transported by being freely suspended in a transport rail to a grinding roller for producing a point at the lower end of the pin. The thus formed pin blank is then transported in the transport rail to a receptacle where the thus machined blanks are collected for further processing. 
     In the known method burrs are formed at the pin end by the grinding process which make an after processing of the blank necessary. When using the pins as directed in a battery, the burrs at the point of the pin end cause the formation of gas bubbles in the anode substance which causes disturbances. Such burrs also soil the apparatus for processing the pins and also present problems in regard to automatic feeding of the pins. 
     In the known method the pin blanks are subjected to a further special treatment in order to remove the burrs at the point of the pin. The pin blanks are filled into vibratory grinding devices where they are machined together with chemicals and grinding agents. This requires time-consuming further machining steps and also machines that take up a lot of space thereby making the manufacture of battery terminals more expensive. Furthermore, the after treatment in the vibratory grinding device can result in an undesirable after treatment and wear at the remaining surface areas of the pin because of the grinding agents. 
     In a method for smoothing an annealed tube, which is to be used as a solid electrolyte in sodium sulfur cells (PATENT ABSTPACTS OF JAPAN, vol. 017, no. 106 M-1375), identical surface areas of the tube, on the one hand, at the end and, on the other hand, on the shaft, are respectively individually treated by two combination rollers. The combination rollers comprise at the same time grinding agents as well as rotating brush means. The rotation axes of the combined rollers extend parallel to the longitudinal axis of the tubes. In both processing steps the axis symmetry and the angle of attack of the grinding and brush means are identical. The piece-by-piece treatment of the tubes by the combination roller is cumbersome and time-consuming. The tubes have no heads so that transport rails cannot be used. Also, at the opposite end of the tubes there are no points to be ground so that a deburring of points is of no concern. 
     In another method for forming points at rod-shaped objects (DE 41 07 871 A1), a receiving device is used for these rod-shaped objects. The receiving device has an exit opening which is arranged at an acute angle to the end face of the grinding wheel. The removal of burrs is not addressed. The circumferential area of the grinding wheel is not used when treating the rod-shaped objects. 
     For polishing needle eyes (DE 36 324) the needles are guided between a slowly rotating disk and a hollowed table. A quickly rotating hollowed steel wire brush rounds off the eye and polishes it. The manufacture of the needle points is carried out independently in a separate device. The treatment of the needle point is not suggested in this device. 
     SUMMARY OF THE INVENTION 
     The invention has first of all the object to develop a reliable method of the kind pursuant to the preamble of claim  1  for producing battery terminals, which method produces battery terminals in a faster and cost-saving manner. This is inventively achieved by the features of the characterizing portion of claim  1  having the following special meaning. 
     According to the invention, a plurality of rotating pins are simultaneously positioned within different processing stages which are taking place in two sequentially arranged but separate sections of the transport rail. The grinding roller for forming the points of the pin blanks is arranged in the first rail section, while an auxiliary individual roller for deburring the pin points is employed in the second rail section. The pins are positioned within these rail sections and are, depending on their respective position in their individual processing stages. At the beginning section the pins are still blanks or intermediate products while toward the final section they are increasingly nearing completion. At the end of the rail the finish-machined pin end products fall into a common receptacle where they are collected for further processing. Moreover, in both rail sections the engagement angle of the rollers at the pin ends is different. This angle is greater at the roller for deburring that is machining the incoming intermediate pin products within the second rail section than the corresponding angle of the grinding roller relative to the blanks within the first rail section. 
     It was found to be beneficial to use a grinding disc as an auxiliary roller in the second rail section. It is also possible, as shown in the disclosed embodiment, to employ the brush roller for the after treatment of the pin points. The invention thus eliminates the conventional separate deburring process for battery terminals. The available guiding of the pin blanks is used according to the invention simultaneously to finish the battery terminals in groups. Because the grinding of the pin points, on the one hand, and the deburring of the finished points, on the other hand, are performed simultaneously but separately in groups in neighboring rail sections on sequentially arranged pins, a considerable time saving is realized. 
     The invention is directed also to a device for performing the method according to claim 1. In the invention a device for grinding the pin points can take over the new function, mentioned already several times, of deburring the finished pin points. An extension of the transport rail is of no concern when the rail sections are positioned vertically staggered and the pins are guided in opposite directions in these sections in a switchback fashion. Accordingly, the device can be designed to have a size that is space-conserving. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Further measures and advantages of the invention result from the dependent claims, the following description, and the drawings. It is shown in: 
     FIG. 1 an electrical battery, shown in longitudinal section and perspectively, which illustrates the use of the inventive battery terminals as directed; 
     FIG. 2 schematically, in a plan view and in a partially cut-away view, a plan view onto the inventive device in which the inventive method steps are carried out in a stepwise manner; 
     FIGS. 3 through 5 schematically a sectional view of the device of FIG. 2 along the shown section line III—III and IV—IV and V—V, respectively; 
     FIG. 6 in a perspective view and enlarged the lower end of the blank after the grinding process; and 
     FIG. 7 the pin point of the finished and deburred pin product in a perspective, enlarged representation analog to FIG.  6 . 
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
     The application situation shown in FIG. 1 shows the finished pin product  10  in its directed use as a battery terminal in an electrical battery  30 . The battery terminal  10  comprises a wide head  11  at one of its pin ends  13  and a point  12  having flattened portion  16 , best illustrated in FIG. 7, at the opposite, other pin end  14 . In some applications, one of which is illustrated in FIG. 1, the battery terminal  10 , can also have a thickened shaft portion  15  in the area of the head  11 , which however may be missing in other cases. 
     As can be seen in FIG. 1, the battery terminal  10  is positioned with a pin axis  17  indicated by a dashed line in the center of the electrical battery  30  and is immersed thereby in the electrolyte  31 . The terminal  10  acts as an anode charge eliminator whereby the negative battery pole is provided by its head  11 . The wide head  11  when mounted provides a good electrical contact with the bottom plate  32  of the cup  33  which serves as a component of the battery housing. 
     FIG. 2 illustrates the inventive method in sequential method steps in connection with the device  20  used with the inventive method. The method steps are identified in FIG. 2 by numerals  21  through  25 , where the following is happening. 
     In a first method step  21  a continuous metal wire  18  is fed into the device and is guided through a guide  26  to a cutting tool  27  which in the following method step  22  allows the production of wire sections  19  of a defined length. Here two matrices  28 ,  29  engaging the wire sections  19  are provided, wherein at least one matrix  28  is movable in the direction of the double arrow  34 . The two matrices  28 ,  29  engage the wire  18  between them, wherein a certain wire end piece  38  projects past the matrices  28 ,  29 . The matrices  28 ,  29  fixedly hold the wire  18 , and in correlation therewith, the cutting tool  27  performs a cutting movement, illustrated by double arrow  37  in FIG. 2, at the end face of the guide  26 . This produces a separated wire section  19 . 
     In the second method step  22  the previously mentioned pin head  11  is produced. For this purpose, a riveting die  35  represented in FIG.  2  and movable axially in the direction of double arrow  36  is provided. The riveting die  35  works within a guide  39  and deforms the wire end piece  38  which projects past the matrices  28 ,  29  so as to shape the head  11  illustrated in FIG.  1 . This results in a pin blank  10 ′ whose appearance can be seen in FIG.  3 . 
     In a plane below the parts of the device  20  performing the second method step  22 , a transport rail  40  is positioned which has a longitudinal rail slot  41 . The pin blanks  10 ′ fall into this slot  41  when the two matrices  28 ,  29  open. They get caught in the slot with their pin heads  11  and project with their shafts freely downwardly. An undesirable pendulum motion transverse to the longitudinal slot extension is prevented by lateral guides  42 ,  42   a ,  43  according to FIG. 3 which can engage different areas of the shaft. The transport  49  within the rail  40  could be realized by a slight incline and the use of gravity. However, a transfer lever  44  is primarily used which performs longitudinal and transverse movements  46 ,  46 ′;  45 ,  45 ′ that can be separated into two phases. These movements not only serve to provide a step-wise transport  49  of the pin blanks  10 ′ but also to rotate the pin blank  10 ′ in the direction of the rotation arrow  47  indicated in FIG.  3 . This rotation  47  is primarily important for the two further method steps  23 ,  24  of FIG.  2 . 
     The transfer lever  44  is embodied as a longitudinal strip which extends parallel to the longitudinal rail slot  41  and has an elastic rubber insert  48  or something similar at the side facing the pin blanks  10 ′. The first movement step, according to arrow  45 , is substantially a transverse approach movement wherein the rubber insert  48  is moved against the shafts of the pins  10 ′ which cannot yield because of the oppositely arranged guide  42  acting as an abutment. The longitudinal movement of the lever  44  then follows, as illustrated by the arrow  46  in FIG. 3, in the desired transport direction of the rail  40 . Subsequently, the engaged pins  10  are entrained and transported within the longitudinal rail slot in the direction of arrow  49  of FIG. 2 within the longitudinal slot  41 . This transport movement  49  causes the pins to roll along the counter abutment in the form of the guide  42  so that the aforementioned rotational movement  47  of the pins  10 ′ results. After a certain transport path in the longitudinal direction  46  the transverse counter movement of the lever  44  in the return direction follows, which is illustrated in FIG. 3 by the arrow  45 ′. Accordingly, the pins  10 ′ are released and the lever  44  performs a longitudinal return movement in a direction counter to the transport direction, indicated by arrow  46 ′ in FIG.  3 . This return movement  46 ′ is terminated when the starting position of the transfer lever  44  has been reached where again the aforementioned transverse movement  45  in an approach direction begins. The other guide  43  below the lever  44  is a plastic or metal strip which also provides a support action for the pins during machining in the method steps  23 ,  24 . 
     This transport rail  40  and the correlated aforementioned transport means are also active in the portions downstream where a grinding roller  50  is positioned which is active in the third method step  23  of FIG.  2 . The grinding roller  50  is arranged on a side opposite the lever  44  and extends with its preferably adjustable rotational axis  51  approximately parallel to the longitudinal rail slot  41 . The rotational direction  57  of the grinding roller  50  is illustrated in FIG. 4 by an arrow. Grinding occurs at the lower end  13  of the pin so that the pin point  12  is formed which has already been indicated in FIG.  4 . An intermediate pin product  10 ″ with a pin point  12  having a configuration as illustrated in FIG. 6 is obtained. Burrs  58  project past the central flattened portion  16  at the lower end  13  of the pin, and these burrs must be removed for the reasons mentioned above. This is carried out in the same device  20  and in the same process during the fourth method step  24  of FIG.  2 . 
     The fourth method step  24  is carried out in a rail section  69  downstream of the section  59  of FIG. 2 in which the grinding process was performed. These two sections  59 ,  68  are expediently staggered vertically and the pins  10 ′ or  10 ″ pass through the sections in opposite direction. At the rail transition  68  a deflection of the guiding action acting on the pins takes place. Within the transitional area of  68  the pins are already transported as intermediate pin products  10 ″ provided with points  12 . In the section  69  a brush roller  60  is provided having bristles preferably in the form of plastic grinding bristles. Grinding particles, such as silicon carbide, are integrated into these plastic grinding bristles. The brush roller  60  ensures that the burrs  58  according to FIG. 6 are removed from the intermediate pin products  10 ″ and that the pin end product  10  shown in FIG. 7 is produced. As can be seen in FIG. 7, the burrs  58  are no longer present in the end product  10 . A smooth and optionally somewhat rounded transition between the cone of the point and the central flattened portion  16  of the battery terminal  10  is present. 
     In FIGS. 4 and 5 the special positions of the grinding roller  50 , on the one hand, and of the brush roller  60 , on the other hand, relative to the machining locations, indicated with reference numerals  52  and  62 , on the lower ends  13  of the pins of the intermediate products  10 ″ or end products  10  can be seen. The rotational axis  51  of the grinding roller  50  is arranged at a smaller vertical spacing  53  from the lower end  13  of the pin than the rotational axis  61  of the brush roller  60  which is also preferably adjustable. The brush roller has a greater vertical spacing  63  as can be seen in FIG.  5 . For a substantially identical diameter of the rollers  50 ,  60 , the respective horizontal spacings  54 ,  64  of the lower ends  13  of the pins to the roller center have a reciprocal ratio to the vertical spacings  53 ,  63 . 
     In FIGS. 4 and 5 the contact tangents  55 ,  65  resulting at the respective machining locations  52 , 62  are illustrated at the respective machining locations  52 , 62 . They form different contact angles  56 ,  66  relative to the respective pin axis  17 . The contact angle  66  of the brush roller  60  is greater than the contact angle  56  of the grinding roller  50 . 
     As can be seen by the rotation arrow  67  in FIG. 5, the brush roller rotates in the same direction as the grinding roller  50 . Accordingly, identical drive means can be used for both of them. The same holds true for the drive of the respective transfer levers  44  in the different sections of the transport rail  40 . 
     As can be seen in FIG. 2, already finished pin end products  10  leave the fourth method step  24  and are then conveyed on the transport rail  40  to a receptacle  70 . The already finished pins  10  are collected here and are available for further processing or assembling, for example, in a battery  30 . In this fifth working step  25  a collection, optionally also a quantity-based separation, of the finished pins  10  is carried out. 
     As already mentioned above, instead of the disclosed brush roller  60  it is also possible to employ a further grinding roller for deburring the pin points. The arrangement however should be as shown in the drawings and as disclosed above. This embodiment has been very successful in practice.