WO1995022178A1

WO1995022178A1 - Pole for electric accumulators

Info

Publication number: WO1995022178A1
Application number: PCT/EP1995/000530
Authority: WO
Inventors: Olimpio Stocchiero
Original assignee: Olimpio Stocchiero
Priority date: 1994-02-15
Filing date: 1995-02-14
Publication date: 1995-08-17
Also published as: ITVI940023A1; ITVI940023A0; IT1267687B1

Abstract

The invention discloses a pole for electric accumulators consisting of a core (11; 110) subdivided into a first area (12; 120) arranged inside the accumulator which presents a larger diameter in relation to a second area (13; 130) protruding from the lid (3; 30) of the accumulator itself. A longitudinal hole (18; 180) drilled in said core (11; 110), receives a screw (4; 40) which couples with a thread (21; 210) arranged in said first area (12; 120) of said core (11; 110) and which realizes the electric connection of said pole (1; 10) with an external electric cable (5; 50).

Description

Pole for electric accumulators.

The invention concerns an improved pole for electric accu- mulators. It is a known fact that in the electric accumulators the inner elements are connected to at least one pair of poles, one being positive and the -other one being negative, pro- truding from the lid, to which the electric conductors for the supplying power for external . use are mechanically connected. It is also a known fact that said poles consist of bodies having an essentially cylindrical shape, which are equipped with sealing mechanisms co-operating with the lid and suited to prevent the electrolyte from leaking and with connecting means suited to allow the mechanical connection of each pole with the corresponding electric cable for supplying power for external use. The poles belonging to the known technique are essentially manufactured according to two embodiments. According to one known embodiment the pole is made of lead and presents an insert arranged inside, preferably made of brass, which is incorporated in the body of the pole during the moulding or casting operations of the pole itself. The insert consists of an innerly threaded body and is co- axially bound in the body of said pole within which it is inserted for almost its entire length, and it is suited to receive a screw which connects the pole to the cable for the connection for external use. According to another known embodiment the pole presents the lower part which is connected to the elements made of lead and the upper part which is connected to the electric cable for the connection for external use which is made of cop- per. In both the mentioned embodiments the upper part of the pole is arranged passing through a corresponding hole drilled in the lid, to which it is attached by means of a threaded ring nut, in case the pole is threaded, or by means of a pressure ring nut, in case the pole is not threaded. The described embodiments belonging to the known technique present, however, some inconveniences. With regard to the poles made of lead with the incorporated insert, a first inconvenience is that, to ensure a good mechanical anchorage from the insert to the pole, the latter must present an outer diameter which cannot be smaller than certain minimum values, beyond which, a good mechanical sealing and a good electric connection between the insert and the pole would not be insured. This fact implies, especially in the accumulators of low capacity, the further inconvenience that, in order to ensure a good mechanical and hydraulic sealing between the pole and the lid, it is necessary to realize poles of considerable dimensions even for accumulators of small capacity for which, from a simple electric point of view of allowable' current density, it could suffice to use poles of smaller sizes. Moreover, since at the increase of the capacity of the accumulator the poles are realized with ever bigger diame- ters, the manufacturer must have available in stock poles with different diameters and he is forced, therefore, to bear the corresponding stock investment. With regard to the poles with the upper part made of cop- per, these, not only present the inconvenience that they are more costly in relation to the previously mentioned poles, but they also present the inconvenience that the electrolyte of the accumulator transmigrates through the poles of the lower part of the pole made of lead and is polluted when it comes into contact with the copper, which in turn is chemically corroded by the electrolyte. Moreover, since the copper corrodes the polypropylene too, it damages both the container and the lid of the accumula- tor. It has already been said that each pole, whatever its construction shape may be, presents its lower part attached to the elements of the accumulator and its upper part arranged passing through a hole drilled in the lid of the accumulator to which it is attached by means of a threaded ring nut or by means of a pressure ring nut. Said ring nuts cause the gaskets with which the pole is equipped to be compressed, thus ensuring the sealing of the electrolyte. Sometimes the use of pressure-inserted ring nuts is prefer- red since it makes it unnecessary to realize threaded poles and sometimes said ring nuts can themselves act as sealing gaskets for the electrolyte in case the same are made of rubber. When the poles are coupled with such pressure ring nuts, they discharge onto the inner elements of the accumulator the stresses which are applied to the ring nut by means ^'of mechanical means when it is coupled externally with the pole and ^"internally with the hole drilled in the lid of the accumulator, and they present, therefore, the inconvenience that said stresses can mechanically deform the elements of the accumulator and damage its functionality. The purpose of the present invention is to eliminate the mentioned inconveniences. In particular, the main purpose of the invention is to realize an improved pole for electric accumulators which, in relation to poles equivalent to it, presents smaller diameters while ensuring electric characteristics and characteristics of mechanical resistance which are compara- ble and sometimes higher in relation to the poles belonging to the known technique. It is another purpose that the pole according to the inven- tion can be realized in a single size and can be applied to accumulators having different capacities, by using pressure or threaded ring nuts always of the same size. It is yet another purpose that the pole according to the invention can be connected with the lid of the correspon- ding accumulator without applying stresses to the under- lying elements of the accumulator. Not the last purpose is that the pole according to the invention entails a lower manufacturing cost in relation to the poles belonging to the known technique and equivalent to them. The described purposes are achieved by the pole for elec- trie accumulators according to the invention which, in accordance with the main claim comprises: - a core subdivided into a first area arranged inside the accumulator and connected to the elements of said accumula- tor which presents a bigger diameter in relation to a second area adjacent to it coupled with a hole drilled in the lid of the accumulator; - a longitudinal hole drilled in said core and suited ^'to receive a screw; - a thread belonging to said core and co-axial with said hole, suited to receive the coupling of said screw in order to obtain the electric connection of said pole with an external electric cable and it is characterized in that said thread is arranged in said first area of said core. According to one preferred embodiment, the thread is direc- tly realized in said first area of said pole. According to another embodiment the thread is obtained in a bush, preferably made of brass, incorporated in said first area of the pole. Said bush presents a tubular shape, the bases of which contrast against as many stopping shoulders which are defined in the body of the pole during the moulding or casting operations and which are suited to prevent the coupling between bush and pole from becoming disconnected. Said bush can be also inserted in the core of the pole by a through hole drilled in the pole itself which is successi- vely closed by means of welding or other means. The bush can present any shape and can be made of conducti- ve materials differing from brass, such as stainless steel, copper or plastic conductive material and similar. Advantageously, the pole according to the invention can be realized in a single size and can be used for batteries having different capacities by using, for its connection -to the electric cable, screws manufactured with different materials so as to allow through the pole/screw unit the flow of a power density which is variable according to the capacity of the accumulator. Moreover, with as much advantage the pole according to the invention can be entirely made of lead, thus resulting more convenient and less liable to be corroded by the electroly- te. Furthermore, advantageously, since this pole is equipped with a thread obtained in its thicker and, therefore, mdre resistant area, the tightening of the screw which connects the electric cable can exert an axial stress suited to simultaneously couple with the pole the ring nut for the connection to the lid too, without stressing the underlying elements of the accumulator. Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific example, while indicating a preferred embodiment of the invention, are given by way of illustration only, since various changes and odifica- tions within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description and from the drawings, wherein: - Fig. 1 shows the improved pole according to the invention represented in an exploded view, together with the lid of the accumulator to which it is connected, with the ring nut for the connection of the pole to the lid and with the screw for the connection of the pole to the electric cable; - Fig. 2 shows the pole and the elements represented in Fig. 1, coupled together; - Fig. 3 shows a different embodiment of the pole according to the invention represented in an exploded view, together with the lid of the accumulator to which it is connected, with the ring nut for the connection of the pole to the lid and with the screw for the connection of the pole to the electric cable; - Fig. 4 shows the pole and the elements represented in Fig. 3, coupled together. As can be observed in Fig. 1, the pole according to the invention, indicated as a whole with 1, consists of a core 11 which presents a first area 12 having a larger diameter in relation to a second area 13 above it which is inserted in the hole 31 drilled in the lid 3 of the container of the elements, not represented in the Figure. The pole 1 is entirely made of lead, preferably by means of moulding ^"or casting processes and its core 11 presents on the outside and in the intermediate position, a ledge 19 against which a sealing gasket 20 contrasts and inside a longitudinal hole 18 which co-axially communicates with a thread 21 obtained in the first area 12. Said thread 21 is suited to receive the coupling of the threaded end 41 of a screw 4 arranged passing through the longitudinal hole 18 which permits the connection of the pole 1 to an electric conductor 5. In particular, said thread 21 is obtained in the first area 12 of the pole 1 under the shoulder 91 which delimits the passage from the first area 12 to the second area 13. Therefore, the second area 13 of the pole 1 does not per- form any mechanical action and, consequently, can be reali- zed in a smaller diameter in relation to the poles belon- ging to the known technique which are equipped with a bush made of brass embedded in the lead-body of the pole. This one, in particular, independently from the capacity of the accumulator to which the pole 1 is connected, can always be realized with the same diameter since, by pro- perly changing the material the screw 4 is made of, the group formed by the pole 1 and by the screw 4 can transfer to the electric cable 5 different current densities, accor- ding to the capacity of the accumulator. Thus, for instance, the pole 1 according to the invention represented in Fig. 1, which consists of the body 11 enti- rely made of lead, can be coupled with a screw 4 made of stainless steel in case the pole 1 itself is applied to accumulators having a small capacity. On the contrary, should the accumulator have a medium capacity, the same pole 1 presenting the same sizes and consisting of the same body 11, can transfer to the elec- trie cable 5 a higher current density, should the screw 4, which connects pole 1 with the electric cable 5, be made 'of brass. Finally, 'in case of batteries having a high capacity, the same pole 1 can transmit to the electric cable 5 even higher current densities, should the screw 4 be made of copper. As an overall general rule, however, the screw can be also realized with other conductive materials of any type, including the conductive materials of the plastic type. Obviously, the pole according to the invention can be applied to the lid of the accumulator both by means of a threaded ring nut, in which case its second area will be provided with a thread and by means of a pressure ring nut 6 as in the example which is being described, represented in the Figs. 1 and 2, in which case its second area 13 will be smooth. When some pressure ring nuts 6 are used, together with the pole according to the invention, the underlying elements of the accumulator are stressed during the assembly. In fact, the connection of the ring nut 6 to the pole 1 and to the lid 3, occurs during the connection of the electric cable 5 to the upper end 17 of the pole 1 itself, by tightening the end 41 of the screw 4 in the screw thread 21. After arranging the second area 13 of the pole 1 into the hole 31 of the lid 3 and the upper ends 64 of the ring nut 6 into the seat 51 of the insulating cap 52 which contains the electric cable 5, the upper end 17 of the pole 1, as can be observed in Fig. 2, is forced into contact against the anchoring element 53 of the electric cable 5 by means of the screw 4 which is first inserted into the longitudi- nal hole 18 of the pole 1 and then tightened into the thread 21. During such a tightening operation the ring nut 6 is forced with its outer surface 62 to be coupled with the inner surface 32 of the hole 31, while its inner surface 61 will be coupled with the first area 13 of the pole 1. The screw 4 exerts, thus, two vertical forces 55 and 18 opposed to one another and acting on the anchoring element 53 of the electric cable 5 and on the pole 1, respectively. Since said forces are equivalent and opposite to one another, they annul each other. None of the forces, there- fore, stresses the underlying elements of the pole 1 during the tightening of the connection formed by pole 1, ring nut 6 and conductor 5. A different embodiment of the improved pole according to the invention, based on the same idea of solution, is represented in the Figs. 3 and 4. In such Figures it can be observed that the pole according to the invention, indicated as a whole with 10, consists, in this case too, of a core 110 subdivided into a first area 120 having an oversized diameter and into a second area above it having a smaller diameter 130. The core 110 of said pole 10 presents on the outside and in an intermediate position a ledge 190 against which a sea- ling gasket 200 contrasts and inside a longitudinal hole 180. Said longitudinal hole 180 co-axially communicates with a thread 210 belonging, in this case, to a bush 20 which is directly embedded in said first area 120 of the pole having an oversized diameter during the moulding or casting phases of the pole itself, since it is arranged inside the mould before the moulding or casting operations . The bush 20 can be realized in any shape provided that this prevents the bush from rotating once it has been embedded in the pole. It presents, therefore, a tubular shape having any outer profile and its bases act as contrast surfaces 220 and 230 respectively, which rest against corresponding stopping shoulders 140 and 150 respectively, realized in an undercut in the pole 10 during the moulding or casting operations. In this way the bush 20 is stably and irremovably embedded inside the first area 120 of the pole 10 and can receive the threaded end 410 of a screw 40 and the pole 10 connec- ted to an electric cable 50. In particular, said bush 20 is preferably made of brass in order to obtain .a better electric conductivity and is embedded in the first area 120 of the pole 10 under the shoulder 191 which delimits the passage from the first area 120 to the second area 130. Also in this case the second area 130 of the pole 10 does not perform any mechanical action and can present a smaller diameter in relation to the poles belonging to the known technique equipped with a bush made of brass. In this different solution too, the pole 10 realized in the second area 130, although it has always the same diameter, can transfer to the electric cable 50 different current densities, by properly changing the material the screw 40 is made of. Also said pole 10 can be applied to the lid 30 of the accumulator either by means of a threaded ring nut, or as in the case represented in the Figs. 3 and 4 which are being described, by means of a pressure ring nut 60. In such a case too, when applying the ring nut 60 by tigh- tening the screw 40, the underlying elements of the accumu- lator are not stressed. It could be seen how, according to what has been described, the pole according to the invention, in both the described embodiments, achieves all the proposed purposes. First of all, the main purpose of obtaining a pole for electric accumulators which, although it presents a single size, can be used for accumulators having different capaci- ties, is achieved. In fact, the current density that the unit formed by the pole and the screw for the connection to the electric cable is able to bear, can be modified by using screws made of materials of different conductivity. Moreover, the same poles can be assembled on lids having different sizes. In addition, the poles according to the invention present smaller sizes but mechanical characteristics which are equivalent and sometimes higher in relation to poles belon- ging to the known technique, since the thread which couples with the screw is entirely embedded in the area of the pole having an oversized diameter. Advantageously, the use of the pole according to the inven- tion makes it possible to connect the pole to the lid and to the electric cable during the connection of the latter and without stressing the underlying elements of the accu- mulator. The housing of the screw inside the thread arran- ged in the area of the pole having an oversized diameter, in fact, permits the assembly of the pressure ring nut on the lid and on the pole by tightening the screw to the electric connection without the help of pressure means. Should the thread present in the pole be obtained in a bush embedded in the pole itself, said bush can be realized with the most different profiles and can present on the outer and/or in the inner surface profiles suited to ensure the best adhesion and mechanical seal conditions in relation to the pole within which it is incorporated. Moreover, the pole according to the invention can be ap- plied to lids of any type by means of ring nuts, also of any type, which can be tightened or pressed. Finally, with regard to the electric, cable, this can be of any type, with or without the protective cap. It is however understood that said changes and other possi- ble modifications must all fall within the spirit and scope of the present invention.

Claims

CLAIMS 1) A pole for electric accumulators comprising: - a core (11; 110) subdivided into a first area (12; 120), arranged inside the accumulator and connected with the elements of said accumulator, said area presenting a larger diameter in relation to a .second area (13; 130) adjacent to it which is coupled within a hole (31; 310) drilled in the lid (3; 30) of the accumulator; - a longitudinal hole (18; 180) drilled in said core (11; 110) and suited to receive a screw (4; 40); - a thread (21; 210) belonging to said core (11; 110) and co-axial with said longitudinal hole (18; 180), suited to receive the coupling of said screw (4; 40) in order to obtain the electric connection of said pole (1; 10) with an external electric cable (5; 50), characterized in that said thread (21; 210) is arranged in said first area (12; 120) of said core (11; 110). 2) A pole for accumulators according to claim 1, characterized in that said thread (21) is realized in the body of said core (11), in said first area (12) of the core (11) itself. 3) A pole for accumulators according to claim 1, characterized in that said thread (210) contained in said core (110) is obtained inside a bush (20) entirely incor- porated in said first area (120) of said core (110). 4) A pole for accumulators according to claim 3, characterized in that said bush (20) creates with said core (110) an unremovably locked coupling by means of one or more contrast surfaces (220, 230) belonging to said bush (20), each of them co-operating with one or more stopping shoulders (140, 150) realized in an undercut in said core (110). 5) A pole for accumulators according to any of the previous claims, characterized in that said core (11; 110) of said pole (1; 10) is made of lead. 6) A pole for accumulators according to claim 3 or 4, characterized in that said bush (20) is made of an electro- conductive material. 7) A pole for accumulators according to claim 1, characterized in that said screw (4; 40) is made of an electroconductive material. 8) A pole for accumulators according to any of the claims 6 or 7, characterized in that_, said electroconductive material is an electroconductive plastic material. 9) A pole for accumulators according to any of the claims 6 or 7, characterized in that said electroconductive material is copper. 10) A pole for accumulators according to any of the claims 6 or 7, characterized in that said electroconductive material is brass. 11) A pole for accumulators according to any of the claims 6 or 7, characterized in that said electroconductive material is stainless steel.