ELECTRICAL CONNECTION TERMINAL AND METHOD FOR ITS MANUFACTURE

Description

[0001] The invention generally relates to electrical terminals and more particularly to an electrical terminal configured to be mounted to a panel, such as a glass panel.

[0002] The windshield and / or rear window of automotive vehicles often have an electrical device such as an antenna or defroster formed on or in the glass. To electrically connect the electrical device to associated equipment, for example, a radio transceiver or defroster control, an electrical terminal is first soldered to the glass in electrical communication with the electrical device. An electrical cable extending from the associated equipment is then secured to the electrical terminal for providing electrical communication therebetween. A problem with some current electrical terminals is that the terminals can be easily separated from the glass by peeling if accidental pulling forces are exerted on the electrical cable. In addition, some electrical terminal designs are prone to cause cracking of the glass during soldering because of heat related stress concentrations formed on the glass by the footprint of the terminal. There remains a need for an electrical terminal which is resistant to the peeling and cracking issues discussed above.

[0003] Publication US 4 951 389 A discloses a method for making a wire-receiving barrel terminal having a barrel with a desired inner diameter. The method comprises the steps of: selecting a metal stock having the desired properties; stamping a terminal blank having a forward portion adapted to be formed into at least one contact section, an intermediate portion extending rearwardly from said forward portion and a rearward portion adapted to be formed into first and second barrel sections. The second barrel section of said rearward portion is joined integrally with and extends rearwardly from said intermediate portion and the first barrel section is joined integrally with and extends from the second barrel section. The first and second barrel sections are generally rectangular and each has at least one lateral edge, and a lateral dimension equal to the circumference of a circle of desired wire receiving barrel inner diameter. In one embodiment first barrel section is laterally offset from second barrel section by bight section. A seamed barrel shaped member is formed from first barrel section. Seamed outer barrel member from second contact section is formed around barrel-shaped member after disposition thereof along a major surface of second barrel section by bending at bight section. The seams of barrel terminal member are essentially diametrically opposed and a continuous portion of the outer barrel member overlies the inner slam. Publication JP 2016 091772 A discloses a bus bar configured to connect neighboring electrode terminals of a plurality of unit cells including the electrode terminals of positive electrodes and negative electrodes. The bus bar comprises a rectangular main body part that bridges the neighboring electrode terminals, and a wire connection part which extends from the main body part and is connected to a terminal of a detection wire. The main body part is configured by folding and overlapping a first plate part and a second plate part which are separated by folding parts. US 6 406 337 B1 discloses the preamble of independent claim 1.

[0004] The subject matter discussed in the background section should not be assumed to be prior art merely because of its mention in the background section. Similarly, a problem mentioned in the background section or associated with the subject matter of the background section should not be assumed to have been previously recognized in the prior art. The subject matter in the background section merely represents different approaches, which in and of themselves may also be inventions.

[0005] According to a first embodiment of the invention, an electrical terminal is provided. The electrical terminal includes a planar base portion having a base portion outer surface, a base portion inner surface, and two securing tabs extending from an edge of the planar base portion. The planar base portion has a first curved perimeter that is generally circular in shape and has a first diameter. The electrical terminal further includes a planar attachment portion having an attachment portion outer surface and an attachment portion inner surface. The planar attachment portion has a second curved perimeter that is generally circular in shape and has a second diameter, wherein the first diameter of the planar base portion is greater than the second diameter of the planar attachment portion. The base portion inner surface is arranged such that it is in contact with the attachment portion inner surface and the two securing tabs are bent over the attachment portion outer surface.

[0006] In an example embodiment having one or more features of the electrical terminal of the previous paragraph, the base portion is integrally formed with the planar attachment portion and the planar base portion is connected to the planar attachment portion by a U-shaped connecting member.

[0007] In an example embodiment having one or more features of the electrical terminal of the previous paragraph, the planar attachment member comprises an arm that is configured to secure the electrical terminal to a wire cable.

[0008] In an example embodiment having one or more features of the electrical terminal of the previous paragraph, the two securing tabs are arranged in opposition to one another.

[0009] In an example embodiment having one or more features of the electrical terminal of the previous paragraph, a width dimension of each of the two securing tabs is equal to 25% or more of a circumferential dimension of the planar base portion.

[0010] According to a second embodiment of the invention, a method of forming an electrical terminal is provided. The method includes the step of providing a sheet metal terminal preform having a top surface and a bottom surface; forming a planar base portion with two securing tabs extending from an edge of the base portion and a planar attachment portion. The planar base portion has a first curved perimeter that is generally circular in shape and has a first diameter, wherein the planar attachment portion has a second curved perimeter that is generally circular in shape and has a second diameter, and wherein the first diameter of the planar base portion is greater than the second diameter of the planar attachment portion. The method also includes the step of bending the connecting member into a U-shape such that the bottom surface of the planar base portion is in contact with the bottom surface of the planar attachment portion. The method further includes the step of bending the two securing tabs such that they are bent over the attachment portion top surface.

[0011] In an example embodiment having one or more features of the method of the previous paragraph, the attachment member comprises an arm that extends from the planar attachment portion.

[0012] In an example embodiment having one or more features of the method of the previous paragraph, the method further comprises the step of deforming the arm to secure the electrical terminal to the wire cable.

[0013] In an example embodiment having one or more features of the method of the previous paragraph, the two securing tabs are arranged in opposition to one another and wherein a width dimension of each of the two securing tabs is equal to 25% or more of a circumferential dimension of the base portion.

[0014] The present invention will now be described, by way of example with reference to the accompanying drawings, in which: Fig. 1 is a perspective top view of an electrical connector in accordance with a first embodiment of the invention; Fig. 2 is a perspective bottom view of the electrical connector of Fig. 1 in accordance with the first embodiment of the invention; Fig. 3A is a cross section view of the electrical connector along the section line 3A-3A in Fig. 1 in accordance with the first embodiment of the invention; Fig. 3B is a cross section view of the electrical connector along the section line 3B-3B in Fig. 1 in accordance with the first embodiment of the invention; Fig. 4A is a top plan view of the electrical connector of Fig. 1 in accordance with the first embodiment of the invention; Fig. 4B is a left side plan view of the electrical connector of Fig. 1 in accordance with the first embodiment of the invention; Fig. 4C is a left end plan view of the electrical connector of Fig. 1 in accordance with the first embodiment of the invention; Fig. 4D is a right end plan view of the electrical connector of Fig. 1 in accordance with the first embodiment of the invention; Fig. 4E is a bottom plan view of the electrical connector of Fig. 1 in accordance with the first embodiment of the invention; Fig. 4F is a right-side plan view of the electrical connector of Fig. 1 in accordance with the first embodiment of the invention; Fig. 5A is a top plan view of an electrical connector in accordance with a second embodiment of the invention; Fig. 5B is a left side plan view of the electrical connector of Fig. 5A in accordance with the second embodiment of the invention; Fig. 6 is a flow chart of a method of forming an electrical connector in accordance with a third embodiment of the invention and Fig. 7 is a top plan view of a terminal preform used for forming the electrical connector in accordance with the third embodiment of the invention.

[0015] Reference numbers of similar elements in the various embodiments share the last two digits of the reference number.

[0016] Examples of electrical terminals that may be soldered to a conductive material applied to a glass surface of an automotive to provide electrical communication with an electrical device, such as an antenna or defroster formed on or in the glass, so that the electrical device may be electrically connected to associated equipment by an electrical cable are presented herein and illustrated in Figs. 1-5B. A method of forming such an electrical terminal is also presented herein and illustrated in Figs. 6 and 7. The electrical terminal, hereinafter referred to as the terminal 100, includes a planar base portion 102 having a base portion outer surface 104, a base portion inner surface 106, and two securing tabs 108 extending from an edge of the base portion 102. The terminal 100 also includes a planar attachment portion 110 having an attachment portion outer surface 112, an attachment portion inner surface 114, and an attachment member 116 extending from the attachment portion outer surface 112. The attachment member 116 is configured to secure a wire cable (not shown). The base portion inner surface 106 is arranged such that it is in contact with the attachment portion inner surface 114 and the two securing tabs 108 are bent over the attachment portion outer surface 112. The securing tabs are arranged in opposition to one another. According to a first example of the terminal 100 shown in Figs. 1-4F, the securing tables are offset by about 180° and a width dimension of each of the two securing tabs 108 is equal to 25% or more of a circumferential dimension of the base portion 102. According to a second example of the terminal 200 shown in Figs. 5A and 5B, the base portion 202 defines four securing tabs 208 that are offset from one another by about 90° configured to secure the base portion 202 to the attachment portion 210. Similarly to terminal 100, the base portion 202 is connected to the attachment portion 210 by a U-shaped strap or connecting member 234 extending from the base portion 202 to the attachment portions and integrally formed with the base portion 202 and attachment portion 210. The width dimension of each of the four securing tabs 208 is less than 25% of the circumferential dimension of the base portion 202. In alternative embodiments of the terminal, the base portion may be attached to the attachment portion by other means, e.g. welding or electrically conductive adhesive.

[0017] The terminal 100 is formed of sheet metal and has a generally curved outer perimeter or edge. The base portion 102 has a first curved perimeter 118 that is generally circular in shape. The attachment portion 110 has a second curved perimeter 120 that is also generally circular in shape. A first diameter of the base portion 102 is greater than a second diameter of the attachment portion 110. The base portion outer surface 104 may be pre-coated with a layer of solder for facilitating the soldering process.

[0018] The attachment member 116 extends beyond the outer perimeter of the attachment portion 110 and is configured to crimp the terminal 100 to a wire electrical cable. The slots 122 extend from the outer perimeter of the attachment portion 110, inwardly about halfway to the center line of the attachment portion 110, thereby forming two wings thereof. The attachment member 116 has an intermediate portion 124 which is bent upwardly at an angle from the proximal end 126 at about the outer perimeter. The distal end 128 of the attachment member 116 includes a crimping portion 130 having two opposed crimping tabs 132 for crimping to an inner conductor wire of the cable (not shown). The attachment member 116 is bent between the intermediate portion 124 and the distal end 128 so that the distal end 128 is positioned parallel to and laterally offset from the attachment portion 110 as well as above the attachment portion outer surface 112.

[0019] The base portion 102 is integrally formed with the attachment portion 110. The base portion 102 is connected to the attachment portion 110 by a U-shaped strap or connecting member 134 extending from the base portion 102 to the attachment portions and integrally formed with the base portion 102 and attachment portion 110.

[0020] In use, the terminal 100 is typically soldered to a glass substrate. The base portion 102 is generally circular in shape and does not tend to cause heat related stress concentrations in glass, and therefore, little or no cracking occurs during the soldering process. The proximal end 126 of the attachment member 116 extends from the attachment portion 110 and so does not interrupt the circular shape of base portion 102. Once soldered, any accidental pulling forces on cable are transferred to the center of base portion 102 because the proximal end 126 of the attachment member 116 extends therefrom. Consequently, the terminal 100 is resistant to being separated from glass.

[0021] The base portion 102 and attachment portion 110 are sized, shaped, and arranged such that forces exerted on the attachment member 116 by the wire cable are laterally distributed across the base portion 102. In addition, the upwardly angled intermediate portion 124 of the attachment member 116 is able to bend or deflect thereby absorbing forces exerted on the terminal 100 by cable. This may lessen the intensity of forces exerted on the base portion 102 by accidental pulling of the cable. For example, if a longitudinal pulling force is exerted on the cable, intermediate portion 124 would bend slightly to the left and absorb some of the force. In addition, if an upward pulling force is exerted on the cable, intermediate portion 124 would bend slightly upwardly and absorb some of the force. The angled intermediate portion 124 is also able to absorb forces that are forwardly and downwardly directed forces. Furthermore, the proximal end 126 of the attachment member 116 may also bend or deflect to absorb forces.

[0022] According to one example, the terminal 100 is formed of C260 brass, the base portion 102 is about 9 mm in diameter, and the terminal 100 is about 13 mm in length. Alternately, the terminal 100 may be formed of other conductive sheet materials. The intermediate portion 124 is bent at about a 45° angle to provide equal force absorbing capabilities for longitudinal and vertical forces. The dimensions of terminal 100 may be varied to suit particular circumstances. Although intermediate portion 124 is preferably bent, alternatively, the intermediate portion 124 may be straight. In addition, the proximal end 126 may be bent instead of the intermediate portion 124.

[0023] The terminal 100 is formed by a stamping and forming process 300 from a terminal preform 400. The terminal preforms 400 may be attached to a carrier strip 444 by severable regions 446 extending from the crimping portion 130 of the attachment member 416 or the connecting member 430 to facilitate handling and processing of multiple terminals. The carrier strip 444 may be cut into to form a multiple terminal soldering assembly, so that multiple terminals may be soldered to glass at the same time. Cables may be crimped to terminals before soldering.

[0024] A method or process 300 of forming the terminals 100, 200 is shown in flowchart form in Fig. 6 and is described below:

[0025] STEP 336, PROVIDE A SHEET METAL TERMINAL PREFORM HAVING A TOP SURFACE AND A BOTTOM SURFACE FORMING A BASE PORTION WITH TWO SECURING TABS EXTENDING FROM AN EDGE OF THE BASE PORTION, AN ATTACHMENT PORTION WITH AN ATTACHMENT MEMBER CONFIGURED TO SECURE A WIRE CABLE TO THE ELECTRICAL TERMINAL EXTENDING THEREFROM, AND A CONNECTING MEMBER INTERCONNECTING THE BASE PORTION WITH THE ATTACHMENT PORTION, includes providing a terminal preform 400, as shown in Fig. 7, having a top surface 440 and a bottom surface 442 forming a base portion 402 with two securing tabs 408 extending from an edge of the base portion 402, an attachment portion 410 with an attachment member 416 configured to secure a wire cable to the electrical terminal extending therefrom, and a connecting member 434 interconnecting the base portion 402 with the attachment portion 410. The terminal preform 400 is formed from sheet metal using conventional sheet metal cutting processes, such as stamping, blanking, or cutting;

[0026] STEP 338, BEND THE CONNECTING MEMBER INTO A U-SHAPE SUCH THAT THE BOTTOM SURFACE OF THE BASE PORTION IS IN CONTACT WITH THE BOTTOM SURFACE OF THE ATTACHMENT PORTION, includes bending the connecting member into a U-shape such that the base portion bottom surface 406 is in contact with the attachment portion bottom surface 414; and

[0027] STEP 340, BEND THE TWO SECURING TABS SUCH THAT THEY ARE BENT OVER THE ATTACHMENT PORTION TOP SURFACE, includes bending the two securing tabs 408 such that they are bent over the attachment portion top surface 412, thereby securing the base portion 402 to the attachment portion 410.

[0028] Accordingly, terminals 100, 200 and a method 300 of forming such terminals 100, 200 is provided. These terminals 100, 200 advantageously provide a base portion 102, 202 in the form of an uninterrupted circle that are less prone to cracking glass when being soldered thereto, The base portion 102, 202 also provides a greater surface area than prior art terminals that had interruptions or gaps in the base portion.

Claims

1. An electrical terminal (100) configured to be soldered to a conductive material applied to a glass surface, comprising: a planar base portion (102) having a base portion outer surface (104), a base portion inner surface (106), and two securing tabs (108) extending from an edge of the planar base portion (102), wherein the planar base portion (102) has a first curved perimeter (118) that is generally circular in shape and has a first diameter; characterised in that it further comprises a planar attachment portion (110) having an attachment portion outer surface (112) and an attachment portion inner surface (114), wherein the planar attachment portion (110) has a second curved perimeter (120) that is generally circular in shape and has a second diameter, and wherein the first diameter of the planar base portion (102) is greater than the second diameter of the planar attachment portion (110), wherein the base portion inner surface (106) is in contact with the attachment portion inner surface (114) and wherein the two securing tabs (108) are bent and overlay the attachment portion outer surface (112).

2. The electrical terminal (100) in accordance with claim 1, wherein the planar base portion (102) is integrally formed with the planar attachment portion (110) and wherein the planar base portion (102) is connected to the planar attachment portion (110) by a U-shaped connecting member (134).

3. The electrical terminal (100) in accordance with any one of the preceding claims, wherein the planar attachment portion (110) comprises an arm that is configured to secure the electrical terminal (100) to a wire cable.

4. The electrical terminal (100) in accordance with claim 3, wherein the arm is deformed to secure the electrical terminal (100) to the wire cable.

5. The electrical terminal (100) in accordance with any one of the preceding claims, wherein the two securing tabs (108) are arranged in opposition to one another.

6. The electrical terminal (100) in accordance with any one of the preceding claims, wherein a width dimension of each of the two securing tabs (108) is equal to 25% or more of a circumferential dimension of the planar base portion (102).

7. A method (300) of forming an electrical terminal (100) configured to be soldered to a conductive material applied to a glass surface, comprising the steps of: providing (336) a sheet metal terminal preform (400) having a top surface (440) and a bottom surface (442); forming a planar base portion (402) with two securing tabs (408) extending from an edge of the base portion (402), a planar attachment portion (410), and a connecting member (434) interconnecting the planar base portion (402) with the planar attachment portion (410), wherein the planar base portion (402) has a first curved perimeter that is generally circular in shape and has a first diameter, wherein the planar attachment portion (410) has a second curved perimeter that is generally circular in shape and has a second diameter, and wherein the first diameter of the planar base portion (402) is greater than the second diameter of the planar attachment portion (410); bending (338) the connecting member (434) into a U-shape such that the bottom surface (406) of the planar base portion (402) is in contact with the bottom surface (414) of the planar attachment portion (410); and bending (340) the two securing tabs (408) such that they overlay the attachment portion top surface (412).

8. The method (300) in accordance with claim 7, wherein the attachment member (416) comprises an arm that extends from the planar attachment portion (410).

9. The method (300) in accordance with claim 8, further comprising the step of deforming the arm to secure the electrical terminal (100) to the wire cable.

10. The method (300) in accordance with any one of the claims 7 to 9, wherein the two securing tabs (408) are arranged in opposition to one another.

11. The method (300) in accordance with any one of the claims 7 to 10, wherein a width dimension of each of the two securing tabs (408) is equal to 25% or more of a circumferential dimension of the planar base portion (402).