Fused car battery therminal and fuselink therefor

Abstract: A fused battery terminal (2) comprises a stamped and formed terminal member (6) an insulative housing (4) integrally moulded over power supply line connection bolts (16, 18), and a battery post mounting member (8) attached to the terminal member (6). The terminal member (6) is rigidly attached to an insulative support member (12) thereby providing a safe and rigid support for a fuse link (54) which is integral with the terminal member (6). Power supply lines can thus be clamped against connection platforms (56) of the terminal member (6) by the bolt (18) and are thus directly connected to the battery post via the fuse link (54). Functions such as airbags can be directly connected to the battery post without going through the fuse by clamping with a bolt (16). Safety and reliability of the fuse connection between the battery and power supply lines are thus enhanced due to the integral forming of the fuse link onto the battery post connection section.

Description: This invention relates to an automotive fuse-link and to a battery terminal incorporating a fuse-link. There is a demand in the automobile industry to provide fuses in the power supply lines connected to a battery. The fuses must support considerable electrical currents prior to blowing, as nominal car power needs may be in excess of 100 amperes. Due to the extremely high currents, a poor contact between the fuse and the supply line interconnecting to the battery, may generate high temperatures for a long period that could be a cause of a fire. There is therefore a need to ensure that the fuse interconnecting the power supply and battery is properly connected thereto. In the prior art, however, such fuses have typically been separate parts that are connected by bolts on one end to the power supply line and on the other end to the line leading to the battery terminal. Insufficient torque of the connection bolts, or loosening thereof, has caused fires in certain instances. FR-A-2 096 655 discloses a motor vehicle battery connector incorporating a fuselink and comprising a battery post clamping member and a power supply connection member for connection to a power supply cable of the motor vehicle. The connector has a support member made from plastic material and a fuselink is disposed between bars projecting from the connecting members and over the support member. WO-88/01790 describes a fuse which is suitable for a motor vehicle and which is in the form of an integrated unit comprising a central melt bridge between end portions for connecting the fuse in an electrical circuit. To preserve the mechanical shape and integrity of the fuse, the end portions are held together by a central jacket. The performance requirements of a fuse for use with a battery terminal are very difficult to meet because, for example, the fuse should blow at 600 amperes within less than a second, but withstand start motor current peaks of 300-400 amperes for up to ten second whilst nevertheless blowing at 150 amperes over extended times. Furthermore, all these characteristics must remain substantially constant over the specified lifetime of the vehicle. There is therefore a need to provide a high current fuse-link that can be easily ▪tuned▪ to match the desired operating specifications in a reliable but cost-effective manner. Other high current fuse applications could of course also be subject to the same problems and benefit from the same solutions to these problems. It is also desirable to provide a cost-effective and reliable battery terminal fuse that allows simple and safe connection of power supply lines directly thereto. It is an object of the present invention to provide a fuse-link for high current applications that can be easily tuned for adjustment to satisfy complex operating specifications such that the fuse-link functions reliably over its specified lifetime. The invention consists in a fuse-link for a high current application, comprising a fuse portion which melts or blows when subject to predetermined electrical currents for specified minimum times, and a pair of spaced-apart support bars each integral, respectively, with a connection section and a battery terminal section, the fuse portion being supported by and extending between the pair of support bars, characterised in that the support bars are linked to the connecting and battery terminal sections, respectively, by transition portions of reduced width relative to the widths of the support bars, in the transverse direction of the fuse-link, and the fuse portion is made of a fusible material having a lower melting point temperature than the material of the support bars. The invention is particularly suitable for use in a fuse assembly for interconnecting power supply lines to an automobile battery. Such a fuse assembly may have a stamped and formed sheet metal terminal comprising the supply line connection section and the battery terminal section connected via the fuse link which is blowable when subjected to sufficiently high electrical current. The battery section comprises an integral battery post connection portion insertable over a battery post of an automobile battery for electrical connection thereto. Because the fusible material of the fuse portion has a lower temperature melting point than the support bars, it melts and falls off the support bars when excessive electrical current flows therethrough, thereby breaking the electrical connection. The support bars are substantially interlinked only by the fusible material which may be made of tin, or tin alloy. The reduced width transition portions linking the support bars to the connecting and battery terminal sections are adjustable in width and length for mainly varying the heat transfer from the support bar to the connecting and battery terminal sections in order to control the fuse-blowing characteristics. A preferred embodiment of this invention comprises an insulative support platform to which the connecting and battery terminal sections of the terminal are securely fixed, whereby threaded mounting bolts are securely attached to the support member, for example inmoulded, to allow secure tightening of the power supply lines to the terminal. In order that the present invention may be more readily understood, reference will now be made to the accompanying drawings, in which:- Figure 1 is an isometric view of a fuse battery terminal; Figure 2 is a side view of the terminal of Figure 1; Figure 3 is a top view of the terminal of Figure 2; Figure 4 is a cross-sectional view through lines 4-4 of Figure 3; Figure 5 is a cross-sectional view through lines 5-5 of Figure 3; Figure 6 is a top view of a stamped and formed base plate; Figure 7 is a side view of the base plate of Figure 6; Figure 8 is a cross-sectional view through lines 8-8 of Figure 7; Figure 9 is an isometric view of a support member; Figure 10 is a top view of the support member; Figure 11 is a partial cross-sectional side view of the support member; Figure 12 is an end view of the support member Figures 13 and 14 are side and top views of a bolt member 4 for inmoulding in the support member; Figures 15 and 16 are side and bottom views respectively of an insulative cover member for mounting to the support member; Figures 17 and 18 are plan and side views respectively, of another embodiment having a different fuse link design; Figure 19 is a top view of an embodiment of a fuse battery-terminal member according to this invention; Figure 20 is a view in the direction 20 of Figure 19; Figure 21 is a view in the direction of arrow 21 of Figure 19; Figure 22 is an exploded isometric view of a fuse battery terminal incorporating the terminal member according to the embodiment of Figures 19-21 but also showing the support housing members; and Figure 23 is another exploded isometric view of the terminal of Figure 22 but from a bottom side of the terminal. Referring first to Figures 1-5, a fused battery terminal 2 is shown comprising a support member 4, a stamped and formed electrical terminal member 6 and battery post mounting member 8. The battery post mounting member 8 has a rotatable cap 10 that cooperates with conical jaws for clamping onto a battery post of an automobile battery. The mounting member is a known design and is not explained here in any detail. The terminal member 6 could be interconnected to the battery post by any other mounting means. Referring now to Figures 9-12, the support member 4 will be explained in more detail. The support member 4 comprises an insulative moulded housing 12, an insulative fuse cover 14 (see Figures 15 and 16), and power and safety supply bolts 18, 16 having head portions 20 inmoulded to the insulative housing 12. The support member 4 has a first power supply section 22 and a second battery terminal section 24 separated by a fuse section 25 extending therebetween. The power supply connection bolt 18 is inmoulded to the first section 22 and the other safety power supply bolt 16 is inmoulded to the second section 24. Both first and second sections 22, 24 comprise pairs of retaining walls 26 extending outwardly from opposing side surfaces 28, 30 of the housing 12. The fuse section 25 has an upper surface 32 which is recessed with respect to the upper surface 34 of sections 22, 24. The fuse section 25 further comprises a pair of mounting cavities 36 for receiving pins 38 of the cover 14 (see Figures 15 and 16) for mounting of the cover thereto. The cover 14 has mounting surfaces 40 surrounding the base of the mounting pins 38 and a fuse cover surface 42 which is recessed with respect to the surfaces 40. Referring to Figures 13 and 14, the bolt 18 is shown comprising a threaded portion 44 and the head portion 20 which has a cylindrical anchoring portion 46 for supporting the bolt within the overmoulded housing 12, and a hexagonal extension 48 for preventing rotation of the bolt within the housing. The bolt 16 has a smaller diameter than the bolt 18 but has a head of a similar construction to that of the bolt 18. Referring now to Figures 6-8, the terminal member 6 is shown having a first section 50 and a second section 52 separated by a fuse link 54. The first terminal section 50 comprises a connection platform 56 from which extend four mounting tabs 58, the connection platform 56 comprising a hole 60 for receiving the bolt 18 therethrough. The second terminal section 52 similarly comprises a connection platform 62 from which extend mounting tabs 64, the connection platform 62 also comprising a hole 66 for receiving the bolt 16 therethrough. The second terminal section 52 is integrally attached to a battery post connection section 68 to which the battery post mounting member 8 is mechanically and electrically connected. The connection section 58 comprises mounting member fixing tabs 70 extending outwardly from a circular base portion 72, the base portion having a circular cutout 74 for mounting over and around the battery post. The cutout 74 is bounded by a truncated conical section 76 that extends upwards from the base section 72. The fuse link 54 is coined such that it has a material thickness thinner than the sheet metal from which the terminal member 6 is stamped and formed (as best shown in Figure 7), the fuse link having a thin central section 80 which is the point of highest resistance thereby melting and breaking the electrical circuit when subjected to excessive electrical current. Referring to Figures 1-5, the terminal member 6 is shown mounted to the support member 4 whereby the mounting arms 58 are wrapped around the sides 24, 30 of the housing 12 and are retained from forward and rearward movement by retaining walls 26 which help to strengthen and protect the tabs from damage once wrapped around the housing 12. The fuse cover 14 is then mounted to the housing 12, and the pins 38 are bonded to the holes 36 by an ultrasonic welding process such that the fuse link 54 is protected from damage and deposits of material from the environment that may alter its fuse blowing characteristics. The housing and cover recesses 32, 42 allow a sufficient gap to the fuse link such that during the melting process the fuse link does not sag and enter into contact with the cover or housing which would alter the fuse blowing characteristics. Power supply connections can thus be bolted to the bolt 18 and pressed against the terminal connection platform 56 thereby electrically connecting the power supply lines to the battery terminal via the fuse link 54. Certain electrical components such as the airbag, must function at any moment, and are therefore connected directly to the battery post by being clamped around the bolt 16 against the connection platform 62 which has a direct connection to the battery terminal. If the fuse link 54 blows due to a short circuit in the main power supply of the automobile, the safety functions will nevertheless still be connected to the battery. Referring now to Figures 17 and 18, another embodiment is illustrated whereby an alternative fuse link 54' having a thin central section 80' that blows when excessive current flows therethrough. The fuse link 54' comprises a U-shaped portion 82 that comprises a pair of spaced apart extensions 84 connected to a connection platform 62' at first ends 86 thereof and connected to a transverse bar 88 extending between other ends 91 thereof. The fuse link 54' further comprises a central bar 90 that extends between a central position on the transverse bar 88 and a terminal connection platform 56' similar to the terminal connection platform 56 of the previous embodiment. The central bar 90 comprises the central portion 80' which has a central hole filled with a tin bead 92, the central portion 80' further comprising indents 94 for thinning the cross-section between the bead and outer edges 96 of the central bar 90. Use of a tin bead is known for example in U.S. Patent 2,055,866, and has the effect of reducing the blowing temperature of the fuse link by producing a different alloy when melting, thus improving the blowing characteristics of the fuse link. The lower blowing temperature also reduces the sagging effect of the fuse link which, if it touches the support member 32, may cool down and not blow at the required electrical current. The U-shaped element 82 is particularly advantageous in that it provides a sturdy support for the central fuse bar 90 by being supported at two spaced apart points, whilst nevertheless allowing expansion of the central bar 90 due to thermal digitation, in particular because the central bar is connected to a central position on the transverse bar 88 which can thus bend inwards to allow for expansion. Thermal dilatation must be compensated for as the fuse link may otherwise bend excessively and either break prematurely or touch the supports surrounding it, or possibly by other means change the blowing characteristics. The above design, however, provides a sturdy support for the fusing bar 90 whilst nevertheless allowing thermal digitation. Advantageously therefore, the battery terminal member 6 is integrally connected to the battery post connection portion 68, and the power supply connection sections 50, 52 are strongly and rigidly held to a support member 4 that allows reliable and simple clamping of power supply lines to either end of the fuse link whilst providing a rigid and safe support for the fuse link 54 therebetween. Referring now to Figures 19 to 23, another embodiment of a fuse battery terminal 102 is shown comprising a support member 104, a stamped and formed electrical terminal member 106, and battery post mounting members 108. The terminal member 106 comprises a first connection section 150 and a second battery terminal section 152 separated by a fuse-link 154. The first and second sections 150,152 comprise mounting tabs 164 for mounting to the support member 104 in a similar manner to that described in the embodiment of Figures 1-18. The fuse battery terminal 102 differs from the fuse terminal 2 principally in the fuse link section 154 of the terminal member 106 and in the fuse section 125 of the support member 104 as will be described hereinafter. The battery post connection section 168 in the embodiment of Figure 22 also differs in that it is attached to a lateral extension extending from the terminal section 152. The position of the battery post connection section 168,68 will depend on the particular geometrical requirements of the particular application. The terminal fuse-link section 154 will now be described in more detail. The fuse-link section 154 comprises a fuse portion 180 which is a bar of fusible material, the material being of tin or tin alloy for example, interlinking support bars 181,183. The fuse portion 180 can be attached, for example, by reflow of the tin between the support bars. The support bars 181,183 have a width W2 and are integrally linked to respective base sections 150,152 via reduced width transition portions 185,187 respectively. The fusible material bar 180 has a lower melting point than the base sections and support portion material which could be, for example, brass. The reduced width transition portions 185,187 have a certain width W1 and a certain length L that can be varied to adjust the quantity of heat transfer through the transition portions from the fuse-link section. The rate of heat transfer flowing out of the fuse portion 180 will determine the blowing characteristics thereof. Changing the width and length of the transition portions 185,187 can be effectuated by simple changes to the stamping die from which the terminal member is stamped, thus making it easy to change the characteristics if required, as well as providing easily measurable parameters that can be directly measured and linked to their corresponding test curves, thus making it easy to control the design of the fuse and any modifications required by changes in the specifications. During excessive currents over specified time, the bar of fusible material 180 melts and falls off (or is blown off) the support bars 181,183 by gravitational force (or vaporization). If the fusible material does not fall off by gravitation, it will vaporize and blow off the support members because molten tin has an electrical resistance about three times greater than when in the solid state, so it will heat up very rapidly once in the molten state. The fuse-link 154 does not provide an integral interconnection between the support members 181,183, rather the fusible bar of material 180 spans fully across the whole length of the support bars such that no connection between the support bars subsists once the molten tin has fallen off. The blowing characteristics of the fuse-link is more reliable in this way as integral links between the support members may not blow sufficiently quickly at very high current peaks. The housing support member 104 comprises upstanding pins 127 projecting from the fuse section 125 below the fuse-link section 154 of the terminal member 106 when mounted to the support member. A cover member 114 that is mountable over the fuse-link 154 and securely fixable to the support member 104, also comprises pins 129 projecting from a top wall 142 of the cover 114 towards the terminal member fuse-link section 154. The pins 127,129 serve to capture the molten fusible material when it drops off the support bars 181,183 to prevent the fusible material from flowing and accidentally reconnecting the first and second sections 150,152 of the terminal member. In this embodiment, the cover 114 is securely attached to the support member 104 by interengaging latching means 131,133 which allows quick assembly thereof. Advantageously therefore, the provision of support bars integrally interconnected to respective sections of the terminal via reduced width portions, and provided with a fusible material with low melting point temperature spanning across the whole width of the support members provides a very high temperature fuse with finely adjustable blowing characteristics. Furthermore, there is no risk of sagging or other such problems related to fuses where the support bars are integrally interlinked.

Claims: A fuse-link (154) for a high current application, comprising a fuse portion (180) which melts or blows when subject to predetermined electrical currents for specified minimum times, and a pair of spaced-apart support bars (181,183) each integral, respectively, with a connection section (150) and a battery terminal section (152), the fuse portion (180) being supported by and extending between the pair of support bars (181,183), characterised in that the support bars (181,183) are linked to the connecting and battery terminal sections (150,152), respectively, by transition portions (185,187) of reduced width (W1) relative to the widths (W2) of the support bars, in the transverse direction of the fuse-link, and the fuse portion (180) is made of a fusible material having a lower melting point temperature than the material of the support bars. The fuse-link of claim 1, wherein the transition portions have lengths (L) in a direction towards and away from the support bars (181,183) and the widths (W1) and lengths (L) of the transition portions are adjusted to predetermine the amount of heat transfer from the support bars (181,183) to the connection and battery terminals sections (150,152), respectively. The fuse-link of claim 1 or 2, wherein the support bars (183,181) are of substantially the same width (W2) as the fuse portion (180). The fuse-link of claim 1, 2 or 3, wherein the support bars are spaced-apart at a substantially constant spacing over their widths (W2). An automobile battery connector (102) comprising a battery post mounting member (108) for connection to a battery post, and a power supply connection member (104,106) for connection to a power supply conductor of the automobile, wherein the power supply connection member comprises an insulative support member (104) and a terminal member (106) fixed thereto and comprising a fuse link (154) according to any one of claims 1-4, the battery terminal section (152) having a portion (168) mechanically and electrically connected to the post mounting member (108). The connector of claim 5, wherein the power supply connection section (150) comprises a connection platform against which power supply conductor of the automobile can be clamped for electrical connection thereto. The connector of claims 5 or 6, wherein the battery terminal section (152) comprises a connection platform against which a conductor for a safety function of the automobile can be clamped for electrical connection thereto. The connector of claims 6 or 7, wherein deformable tabs (164) extend from the or each connection platform for fixing thereof to the support member (4,104). The connector of claim 8 wherein the support member (104) comprises an insulative housing having an upper surface upon which the terminal connection platforms are mounted, an opposing bottom surface and opposing sides extending therebetween, whereby the deformable tabs are wrapped around the sides and bottom surfaces. The connector of claim 9, wherein the support member (104) comprises retention walls projecting from the sides for guiding and retaining the connection platforms to the support member. The connector of any one of claims 5-10, wherein the support member comprises a power supply connection section, a battery section, and a fuse section (125) extending therebetween, the connection and battery sections having upper surfaces from which the upper surface of the fuse section (125) is recessed. The connector of claim 11, wherein the power supply connection section comprises a bolt inmoulded thereto for clamping of a conductor to the power supply platform. The connector of claims 11 or 12, wherein the support member battery section comprises a bolt inmoulded thereto for clamping of a safety function conductor to the battery connection platform. The connector of claim 11, 12 or 13, wherein an insulative cover (114) is mounted on the fuse section (125) of the support member to protect the fuse link (154) from damage or deposits of dirt. The connector of claim 14, wherein the fuse section (125) is spaced-apart from the fuse-like (154) and comprises upstanding pins (127) projecting towards the fuse-link (154) for capturing molten fusible material for the fuse-link. The connector of claim 14 or 15, wherein the cover (114) has pins (129) projecting towards the fuse-link for capturing molten fusible material.

Inventors: BEDNAREK ALAIN, JODON DE VILLEROCHE FRANCOIS, KUGENER STEPHANE, MANSUTTI PATRICK, PICAUD JEAN-PIERRE, BEDNAREK, ALAIN, JODON DE VILLEROCHE, FRANCOIS, KUGENER, STEPHANE, MANSUTTI, PATRICK, PICAUD, JEAN-PIERRE
Applicants: WHITAKER CORP, THE WHITAKER CORPORATION
Application year: 1995
Main classification: B60R16
IPC codes: H01H85, H01R11, B60R16