A METHOD OF ASSEMBLING A STORAGE BATTERY

Abstract: A terminal post (1) for a storage battery and comprising a hollow terminal portion (3) and a post on which the terminal portion stands. The terminal portion is open at its upper end and has in the side wall thereof a horizontal opening or open­ ings communicating with the interior. Synthetic resin material (7) filling the said opening or openings forms a connection be­ tween a body of synthetic material within the terminal portion and synthetic resin material (7) surrounding the base of the terminal portion by which the terminal post can be fused or bonded to the cover of a storage battery to form a liquid tight seal. There is a saving in the amount of lead alloy needed as compared with conventional terminal posts making the termi­ nal post lighter and cheaper to manufacture.

Description: '4Terminal Posts For Storage Batteries" This invention relates to terminal posts and more particularly terminal posts for storage batteries. In this kind of terminal post, the terminal and post are integrally cast of a lead alloy. However, the terminal and its base are required to be of a predetermined mechanical strength and are therefore made thicker than required for the electric conduction. This is unsatisfactory not only because a large amount of lead alloy is required but also because cracks and burns occur due to the non-uniform thickness. Simply to make the terminal hollow or thin would reduce the mechanical strength and be likely to give rise to other problems in production and practice. With the aim of overcoming these problems we propose, in accordance with the present invention, a terminal post for a storage battery, comprising a terminal portion standing on a post, the terminal portion and the post being formed integrally of lead alloy, characterised in that the terminal portion is hollow and is open at its upper and has in the wall thereof an opening which is filled with synthetic resin material forming a connection between a body of synthetic resin material within the terminal portion and synthetic resin material surrounding the base of the terminal portion. Other features of the present invention are set forth in the appendent claims and in the following description, by way of example, of embodiments of the invention shown in the accompanying drawings in which Fig. 1 is a vertical cross-section of a terminal post for a storage battery according to the present invention; Fig. 2 is a vertical cross-section of a casting comprising a hollow terminal standing upon an integral post; Fig. 3 is a sectioned view showing the casting of Fig. 2 inserted in a mold for synthetic resin material; Fig. 4 is a vertical section of part of a storage battery cover; Fig. 5 is a vertical section of the part of the battery cover of Fig. 4 fitted with the terminal post shown in Figure 1; Fig. 6 is a vertical section of another embodiment terminal post according to the present invention; Fig. 7 is a cross-section on line VII - VII' in Fig. 6; ; Fig. 8 is a vertical section of a part of a storage battery cover; Fig. 9 is a vertical section of the terminal post of Fig. 6 fitted to part of the storage battery cover shown in Figure 8; Fig. 10 is a vertical section of another embodiment terminal post according to the present invention; Fig. 11 is a cross-section on line XI - XI in Fig. 10; Fig. 12 is a perspective view of a storage battery having terminal posts according to the present invention; Fig. 13 is an enlarged part cross-section perspective view of part of the storage battery shown in Figure 12. In Figs. 1 and 5, the reference numeral 1 denotes a complete terminal according to the present invention. Figure 2 shows a body; in this case a lead-alloy casting, la comprising a hollow terminal portion 2 which stands upon and is integral with a post 3. The terminal portion 2 is hollow (6) and is open at its upper end 2-1. At the base 4 of the hollow terminal portion 2 are at least two (two shown) openings 6-1 and 6-2 extending horizontally from the interior 6 of the portion 2 through the wall of the portion 2 and opening into the space between the two lowest of three annular projections at ridges 5 around the terminal base 4. As shown in Fig. 1, the interior 6 of the hollow of three annular projections at ridges 5 around the terminal base 4. As shown in Fig. 1, the interior 6 of the hollow terminal portion 2, the openings 6-1 and 6-2 are filled with a synthetic resin material 7 and a symbol 8 indicating the polarity if the terminal is impressed on the synthetic resin surface at the open upper end 2-1 of the terminal portion. A band 9 of synthetic resin material surrounding the periphery of the terminal base 4 is moulded at the same time as the interior 6 of the hollow terminal portion 2 and the openings 6-1 and 6-2 are filled with synthetic resin material 7 and is integral with that material 7. The reference numeral 10 denotes the upper edge of the synthetic resin surrounding portion. The terminal post of Figure 1 is inserted in a hole 12 formed for this purpose in a cover 11 of a storage battery (See Figure 4) and the upper edge 10 of the synthetic resin band 9 and is joined to the lower face 13 of the cover as illustrated in Fig. 5. To manufacture the terminal post described above, the body la comprising the hollow terminal portion 2, integral post 3 and formed with the terminal post la molded integrally openings 6-1 and 6-2 and sides 5 is first cast in lead alloy. The cast body la (Figure 2) then is inserted in a mold 14 and the mold closed as shown in Figure 3 so defining a cavity 15 around the terminal base 4. A former 16 bearing a symbol indicating the polarity of the particular terminal closes the open end 2-1 of the hollow terminal portion 2. Thereafter, molten synthetic resin injected into the mold 14, flows around the cavity 15, and through the openings 6-1 and 6-2 and eventually fills interior of the hollow terminal portion 2 6-1 and 6-2 so contacting former 16. The synthetic resin is-:then allowed to set and then removed to produce the terminal post shown in Fig. 1, which is filled with synthetic resin and has a moulded band 9 surrounding the terminal base, the band 9 being integrally connected with the synthetic resin filling the terminal portion 2 by resin filling the openings 6-1 and 6-2. The storage battery cover is joined to the battery container (not shown) by fusing together contact surfaces which are first heated, for example, with a hot plate. Conveniently, the upper edge 10 of the resin band 9 and the lower face 13 of the storage battery cover 11 around the hole 12 are heated at the same time, the terminal 2 then being inserted through the hob 12 and the above-mentioned heated surfaces pressed into contact with each other, to produce fused joints between the cover and the battery container and between the terminal post and the cover as shown in Fig. 5, so ensuring a liquid tight seal. Figs. 6 and 7 show another embodiment of terminal post 1' according to the present invention, which differs from the above described embodiment in that external equally angularly spaced projections 17 extending along the terminal portion 2 toward the terminal base 4are provided to prevent rotation of the terminal post in the cover 11, the projections 17 being received in recesses 18 formed in the cover 11 around the hole 12 (as shown in Figure 8). The terminal post 1' fitted in a storage battery cover 11 is illustrated in Fig. 9. Another embodiment of terminal post 1" is shown in Figs. 10 and 11 differs from that in Fig. 1 in that the interior 6' of the terminal portion 2 diverges toward its open upper end, the terminal base 4 has a polygonal (square in the drawing) external flange 4-1 openings 6'-1 and 6t-2 are in a comparatively upper portion of the terminal base 4 and (4) the synthetic material 9t surrounding the terminal base has a polygonal (square in the drawing) external shape. The effect of this is that, when the terminal post is fitted to the battery container cover, a mechanical strength will be retained against the torque. Further, the divergent interior of the hollow terminal portion serves to smooth the movement of the casting mold by the shrinkage of lead in casting the terminal post. Fig. 12 shows the terminal-post 1" of Fig. 10 fitted to the cover 22 of a battery container 21. Fig. 13 is an enlarged partly sectioned view of the battery in Figure 12 showing a plate group 23 and 24, a strap 24 of a plurality of plates of the same polarity. The synthetic resin material may be a thermoplastic resin of particularly a polyolefine resin high in the thermofusibility and preferably polypropyrene. When parts are to be bonded together using a bonding agent, an AS or ABS resin is suitable. In order to determine the size (cross-sectional area) of the hole hollow within the terminal portion, the minimum cross-sectional area of metal must be at least larger than the cross-sectional area of the lower post. Further, the cross-sectional area of the horizontal openings should not be smaller than 0.78 mm (1 mm diameter) only from moulding (jetting) the resin into the hole. If it is stressed to stop the rotation against the force in the terminal rotating 2 direction, a cross-seciontal area of 3 mm (2 mm in the 2 diameter) to 13 mm (4 mm in the diameter) will be adapted. The cross-sectional area of the lead-portion (except the joint hollows) must not be smaller than the cross-sectional area of the lower post portion. That is to say, it is important from the point of view of conduction that the hallow terminal portion has a conducting part with a cross-sectional area not less than the cross-sectional area of the post. In all of the terminal posts described above, the terminal portion is hollow and is filled with synthetic rasin material integrally connected, via the openings communicating with the interior of the terminal portion, with the synthetic resin material surrounding the base of the terminal position. This construction has advantages, in that less lead alloy is required than for conventional terminal posts, the occurrence of cracks and burns is substantially eliminted and the terminal post is lighter (and stronger) than conventional posts. Also, the terminal post can be liquid-tightly secured in a liquid-tight manner to the storage battery cover at the same time as the cover is fused to the battery container. Terminal posts according to this invention can be manufactured and fitted efficiently at a comparatively low cost. The provision of a projection to prevent a rotation of the terminal post ensures that any torque applied to the terminal is resisted and will impair the liquid-tight seal between the terminal post and the cover. By forming a symbol indicating polarity at the upper end of the terminal post the need to provide such a symbol on the cover is avoided so that even when it is required to manufacture two kinds of storage battery which differ only in the arrangement of the polarity, the same cover may be used with obvious advantage in the productivity and control. The synthetic resin filling the hollow terminal portion and surrounding the terminal base may be coloured to facilitate discrimination of polarity (for example, red for a positive terminal post and black or blue for a negative terminal post). This is particularly advantageous since battery containers are often formed of transparent or translucent. material so that even when the storage battery is installed in a confined space, where only one side of the battery can be seen, it will be possible to identify the polarity of the terminals. When the terminal posts are coloured in this way the polarity sign need not be formed at the upper end of the terminal post.

Claims: Claims: 1. A terminal post for a storage battery comprising a hollow terminal portion which is open at its upper end and stands on a post, the hollow terminal portion and the post being formed integrally of lead alloy, and having in the wall of the terminal portion an opening which is filled with a synthetic resin material forming a connection between a body of synthetic resin material within the terminal portion and synthetic resin material surrounding the base of the terminal portion. 2. A terminal post according to claim I and having an external projection which extends downwardly along a side surface of the terminal portion to the base thereof. 3. A terminal post according to claim 1 or claim 2 and having at least two openings in the wall of the terminal portion in the region of the base thereof. 4. A terminal post according to any one of claims 1 to 3 wherein the synthetic resin material within the hollow terminal portion and the synthetic resin material surrounding the base thereof are the same material. 5. A terminal post according to any one of claims 1 to 4 wherein the synthetic resin material is polypropyrene. 6. A terminal post according to any one of claims 1 to 5 wherein a polarity sign is formed on the top surface of the synthetic resin material filling the hollow terminal portion. 7. A terminal post according to any one of claims 1 to 6 wherein the synthetic resin material surrounding the base of the terminal portion is formed to a polygonal shape. 8. A terminal post according to any one of claims 1 to 7 wherein the hollow interior of the terminal portion diverges upwardly from the base thereof. 9. A terminal post according to any one of claims 1 to 8 wherein the synthetic resin material filling the hollow terminal portion and the said opening and surrounding the base of the terminal portion is coloured to indicate the polarity of the terminal. A A storage battery provided with terminal posts according to any one of the preceding claims.

Inventors: HASEGAWA, YOSHIO
Applicants: YUASA BATTERY CO., LTD.
Application year: 1981
Main classification: H01M2
IPC codes: H01M2