Title of Invention

"A PRESSURE CONNECTOR HAVING A PAIR OF OPPOSED FORKED PLATES"

Abstract

A pair of opposed forked plates of a pressure connector are disposed in parallel to each other, and the distance t between the forked plates" is set as follows: [Exp. 4] M.p<t<(0.5-M).p (0.5+M) .p<t<(l-M) .p M={sin-1[WS/(k.d)-Rd/k]}/π 0.4<WS/d<0.6 where d: diameter of said conductor (= diameter of a circumscribed circle of said conductor if it is polygonal in cross section) k: constant p: twist pitch of said conductor Rd: ratio (Sd/d) of the diameter Sd of each strand to the diameter of said conductor t: distance between said forked plates WS: distance between said nipping portions [Effect] All of the strands of the conductor can be brought into contact with at least one of the forked " plates, thereby reducing the contact resistance between the conductor and the pressure connector.

Full Text

The present invention relates to a pressure connector having a pair of opposed forked plates. A pressure connector is known from Japanese Utility Model Laid-open No. 55-21553 entitled "Wire Connecting Device", for example. This publication relates to a wire connecting device capable of simply and efficiently making electrical connection of an insulated wire and another insulated wire at their intersection. This prior art device will now be descried with reference to FIG. 7 corresponding to FIG. 4 of this publication with reference numerals changed. FIG. 7 is a perspective view showing .a' pressure connector in the prior art. Reference numeral 100 generally denotes a metal hook element as the pressure connector. The metal hook element 100 includes a pair of opposed leg portions 101 and 102 (the leg portion 102 being not shown), another pair of opposed leg portions 103 and 104, a pair of hook portions 105 formed at a forked lower end of each of the leg portions 101, 102, 103, and 104, and a conductor holding portion 106 formed between the pair of hook portions 105. Reference numerals 107 and 108 denote two insulated wires, and reference numerals 109 and 110 denote conductors of the wires 107 and 108, respectively. Each of the conductors 109 and 110 is composed of a plurality of strands. [Problem to be Solved by the Invention] FIGS. 8a and 8b are sectional views showing the. conductor 110 connected to the metal hook element 100. More specifically, FIG. 8a shows a contact condition of the leg portion 103 and the conductor 110, and FIG. 8b shows a contact condition of the leg portion 104 and the conductor 110. Referring to FIG. 8a, reference numeral 111 denotes one of the strands constituting the conductor 110. This strand 111 is out of contact with the leg portion 103. In the case that the strands of the conductor 110 are twisted strands, there is a possibility that the strand 111 may be also out of contact with the leg portion 104 spaced a certain distance from the leg portion 103 as shown in FIG. 8b. When at least one of the strands of the conductor 110 is out of contact with both the leg portions 103 and 104 as mentioned above, the conductive sectional area of the conductor 110 is reduced, causing a problem that the contact resistance between the metal hook element 100 (see FIG. 7) and the conductor 110 is increased. It is accordingly an object of the present invention to provide a pressure connector which can reduce the contact resistance. [Means of solving the Problem] Accordingly, there is provided a pressure connector having a pair of opposed forked plates adapted to be pressed against a wire having a conductor formed by twisting a plurality of strands and an insulating cover (El, E2) covering said conductor (Dl, D2) each of said forked plates having a pair of opposed nipping portions spaced a distance smaller than the diameter of said conductor for nipping said conductor/so that characterized in that said forked plates of said pressure connector are parallel to each other and the distance t between said forked plates is set as follows: [Exp. 1] M . p (0.5+M) . p M={ sin-1[WS/(k . d)-Rd/k]}/π 0.4 d: diameter of said conductor (= diameter of a circumscribed circle of said conductor if it is polygonal in cross section) k: constant p: twist pitch of said conductor Rd: ratio (Sd/d) of the diameter Sd of each strand to the diameter of said conductor T: distance between said forked plates WS: distance between said nipping portions All of the strands of the conductor can be brought into contact with at least one of the forked plates, thereby reducing the contact resistance between the conductor and the pressure connector. [BRIEF DESCRIPTION OF THE DRAWINGS] [FIG. 1] FIG. 1 is a perspective view of a pressure connector according to the present invention. [FIG. 2] FIG. 2 is a view taken in the direction shown by an arrow 2 in FIG. 1. [FIG. 3] FIGS. 3a to 3c are views for illustrating a contact condition of first and second forked portions of the pressure connector and a conductor. [FIG. 4] FIG. 4 is a view for illustrating a setting method for the distance between the first and second forked portions. [FIG. 5] FIG. 5 is a graph showing the relation1between WS/d and the number of broken strands in the pressure connector. [FIG. 6] FIG. 6 is a graph showing the relation between WS/d and contact resistance in the pressure connector. [FIG. 7] FIG. 7 is a perspective view showing a pressure connector in the prior art. [FIG. 8] FIGS. 8a and 8b are sectional views showing a conductor of an insulated wire connected to a metal hook element as the pressure connector shown in FIG. 7. [Preferred Embodiment] A preferred embodiment of the present inventionv will now be described with reference to the attached drawings. Each drawing is to be viewed in the same direction as that of reference numerals included therein. . FIG. 1 is a perspective view of a pressure connector 1 according to a preferred embodiment of the present invention. The pressure connector 1 is a member integrally formed from a plate, and it is composed generally of first and second forked portions 2 and 3 as the forked plates in the present invention adapted to be electrically connected to a wire Cl, third and fourth forked portions 4 and 5 as the forked plates in the present invention adapted to be electrically connected to a wire C2, and a base portion 6 for connecting -the first forked portion 2, the second forked portion 3, the third forked portion 4, and the fourth forked portion 5. The wire Cl is composed of a conductor Dl obtained by twisting a plurality of strands (not shown) and an insulating cover El covering the conductor Dl. Similarly, the wire C2 is composed of a conductor D2 obtained by twisting a plurality of strands (not shown) and an insulating cover E2 covering the conductor D2. The first and second forked portions 2 and 3 have the same dimensions, and the third and fourth forked portions 4 and 5 have the same dimensions. The height of the first and second forked portions 2 and 3 is different from the height of the third and fourth forked portions 4 and 5, so as to allow connection of the wires Cl and C2 orthogonally intersecting each other at different levels. The first and second forked portions 2 and 3 respectively have slot portions 7 and 8 for forcibly receiving the wire Cl. Similarly, the third and fourth forked portions 4 and 5 respectively have slot portions 11 and 12 for forcibly receiving the wire C2 . The first and second forked portions 2 and 3 are parallel to each other, and respectively have' inner surfaces 2a and 3a spaced a distance t from each other. Similarly, the third and fourth forked portions 4 and 5 are parallel to each other, and respectively have inner surfaces 4a and 5a spaced the same distance t (not shown) from each other. The conductors Dl and D2 of the wires Cl and C2 have the same diameter d (denoted only for the conductor Dl ) . That is, the diameter d is equivalent to the diameter of a circumscribed circle of each of the conductors Dl and D2 if they are polygonal in cross section. FIG. 2 is a view taken in the direction shown by an arrow 2 in FIG. 1. The slot portion 7 of the first forked portion 2 is composed of a pair of first inclined portions . 7a formed at the lower opening for guiding the wire Cl in receiving the wire Cl into the slot portion 7, a pair of edge portions 7b contiguous to the first inclined portions 7a for stripping off the insulating cover El, a pair of second inclined portions 7c contiguous to the edge portions 7b for compressing and rearranging the strands constituting the conductor Dl, a pair of chamfered portions 7d each formed on the outerv surface of the first forked portion 2 at a poirtioa contiguous to the first and second inclined portions 7a and 7c for enhancing the cover stripping effect of the edge portions 7b, a pair of right and left nipping portions 7R and 7L (as viewed in FIG. 2) contiguous to the second inclined portions 7c for nipping the conductor Dl in its compressed condition, and a rounded portion 7f contiguous to the nipping portions 7R and 7L for preventing stress concentration upon forcing the wire Cl into the slot portion 7. The slot portion 8 has the same shape as that of the slot portion 7, so the description thereof will be omitted herein. In FIG. 2, reference numerals 8R and 8L denote right and left nipping portions of the slot portion 8 of the second forked portion 3 for nipping the conductor Dl in its compressed condition. The right and left nipping portions 7R and 7L are spaced a distance WS, and the right and left nipping portions 8R and 8L are also spaced the same distance WS (not shown) . FIGS. 3a, 3b, and 3c illustrate a contact condition of the first and second forked portions 2 and' 3 and the conductor Dl. More specifically, FIG. 3a is a side view of the first and second forked portions 2 and 3 and the conductor Dl forcibly received therein (the insulating cover El is not shown); FIG. 3b is a cross section taken along the line b-b in FIG. 3a; and FIG. 3c is a cross section taken along the line c-c in FIG. 3a. As shown in FIG. 3a, the slot portions 7 and 8 (see FIG. 1) of the first and second forked portions 2 and 3 are in pressure contact with the conductor Dl composed of twisted strands. The strands constituting the conductor Dl are twisted counterclockwise as viewed from the first forked portion 2 toward the second forked portion 3 in FIG. 3a, for example. One of the twisted strands is denoted by reference numeral F as shown by a hatched portion in FIG. 3a. The strand F near the first forked portion 2 is present at an upper portion of the conductor Dl, and spirally extends on the back side of the conductor Dl as shown by a broken line in FIG. 3a to reach the front side of the conductor Dl near the second forked portion 3. As shown in FIG. 3b, the strand F is out of contact with both the right and left nipping portions 7R and 7L of the first forked portion 2 . As shown in FIG. 3c, the strand F is in contact with the right nipping portion 8R of the second forked portion 3 . The strand F can be made in contact with either the first forked portion 2 or the second forked portion 3 by setting the distance t, described hereinafter, between the first and second forked portions 2 and 3 (see FIG. 3a). Similar comments apply to the other strands of the conductor Dl . A setting method for the distance t between the first and second forked portions 2 and 3 will now be described. FIG. 4 illustrates the setting method for the distance t according to the present invention, showing a state that the conductor Dl of the wire Cl (see FIG. 1) is nipped between the nipping portions 7R and 7L of the first forked portion 2 and between the nipping portions 8R and 8L of the second forked portion 3. The cross sections of the first and second forked portions 2 and 3 shown at a lower portion of FIG. 4 correspond to FIGS. 3b and 3c, respectively. A setting method for the distance t between the third and fourth forked portions 4 and 5 is similar to that for the distance t between the first and second forked portions 2 and 3, so the description thereof will be omitted herein. When the conductor Dl having the diameter d is forcibly inserted between the right and left nipping portions 7R and 7L (and between the right and left nipping portions 8R and 8L) spaced the distance WS from each other, the conductor Dl is compressed to be deformed into a shape like a vertically elongated oval as viewed in cross section. In FIG. 4, reference symbol P denotes a strand positioned closest to (not in contact with) an upper portion of the right nipping portion 7R of the first forked portion 2, and reference symbol Q denotes a strand positioned closest to (not in contact with) an upper portion of the left nipping portion 7L on the counterclockwise side of the strand P. At the second forked portion 3, the strand P may take any one of positions R, S, T, U, V, and W shown in FIG. 4. Similarly, the strand Q may take any one of the positions R, S, T, U, V, and W at the second forked portion 3. The positions R and W are upper end positions where the strands P and Q come into contact with the nipping portions 8L and 8R of the second forked portion 3, respectively. The positions T and U are lower end positions where the strands P and Q come into contact with the nipping portions 8L and 8R, respectively. Reference symbol CV denotes a center line between the nipping portions 8L and 8R (or between the nipping portions 7L and 7R) ; reference symbol CH denotes a center line of the conductor Dl in its vertical direction; and reference symbol G denotes a point of intersection of the center lines CV and CH. The positions R and U are symmetrical with respect to the point G, and the positions T and W are also symmetrical with respect to the point G. The other positions S and V will be hereinafter described. Further, reference symbols Rc, Tc, Uc, and Wc denote centers of the strands P and Q at the positions R, T, U, and W, respectively, and reference symbol- θ denotes an angle formed between the center line CV and a straight line WcTc. Accordingly, wcGRc=2θ. Further, reference symbol tw denotes a direction of twist of the conductor Dl. There will now be described a condition that the strands P and Q come into contact with either the left nipping portion 8L or the right nipping portion 8R of the second forked portion 3 . It is assumed that the strand P comes into contact with the left nipping portion 8L ranging from the position R to the position T. When the strand P is present at the position T, for example, the strand Q comes to a position between the position T and the position U, so that the strand Q is out of contact with both the left nipping portion 8L and the right nipping portion 8R. To make both the strands P and Q into contact with the left nipping portion 8L, the strand P must be located between the position R and the position S where the position S is a position shifted clockwise by an angle of 2d from the position T, that is, must be located in the range X. Accordingly, the condition for making both the strands P and Q into contact with the left nipping portion 8L is. obtained as follows: (Equation 1 Removed) where Φ1 is an angle of twist of the conductor Dl from the first forked portion 2 to the second forked portion 3 in this case. Similarly, to make both the strands P and Q into contact with the right nipping portion 8R, the strand P must be located between the position U and the position V where the position V is a position shifted clockwise by an angle of 2θ from the position W, that is, must be located in the range Y. Accordingly, the condition for making both the strands P and Q into contact with the right nipping portion 8R is obtained as follows: (Equation 2 Removed) where Φ2 is an angle of twist of the conductor Dl from the first forked portion 2 to the second forked portion 3 in this case. Letting p denote the twist pitch of the conductor Dl in its longitudinal direction such that the strands of the conductor Dl are twisted by 2π, the distance t between the first and second forked portions '2 and 3, the twist angles Φ1 and Φ2, and the twist pitch p are related as follows: t: p=Φ11:2 π or t:p=Φ2:2π Accordingly, (Equation 3 Removed) or (Equation 4 Removed) From Eqs. (1) and (3), the following relation is given. (Equation Removed) Accordingly, (Equation 5 Removed) From Eqs. (2) and (4), the following relation is given. (Equation Removed) Accordingly, (Equation 6 Removed) Letting k-d denote the length of the straight line WcTc (this length is a distance from the position W to the position T of the strand P (or Q) when the conductor Dl is deformed, and this distance is equal to a value of k times the diameter d of the conductor Dl where k is the multiple (constant) empirically obtained), and letting Sd denote the diameter of the strand P, the following equation holds. sinθ = (WS-Sd)/(k-d) Accordingly, (Equation 7 Removed) Insertion of M=θ/π into Eqs. (5) and (6) respectively results in: (Equation 8 Removed) (Equation 9 Removed) Thus, Eq. (8) or (9) is the condition for making the plural strands p and Q (and all the other strands) of the conductor Dl into contact with either the first forked portion 2 or the second forked portion 3. FIG. 5 is a graph showing the relation between WS/d and the number of broken strands in the pressure connector according to the present invention. In FIG. 5, the vertical line represents the number of broken strands of the conductor Dl (or the conductor D2), and the horizontal line represents WS/d that is the -ratio of the distance WS between the nipping portions 7L and 7R (or the nipping portions 8L and 8R) to the diameter d of the conductor Dl (or the conductor D2) (see also FIGS. 1 and 4). When WS/d is small, i.e., when the ratio of the distance WS between the nipping portions 7L and 7R (or 8L and 8R) to the diameter d of the conductor Dl (or D2) is small, the conductor Dl (or D2) is forcibly inserted between the nipping portions 7L and 7R (or 8L and 8R) to be heavily deformed, resulting in an increased number of broken strands of the conductor Dl (or D2). When WS/d is increased, i.e., when the ratio of the distance WS between the nipping portions 7L and 7R (or 8L and 8R) to the diameter d of the conductor Dl (or D2) is increased, the conductor Dl (or D2) can be relatively . easily inserted between the nipping portions 7L and 7R (or 8L and 8R), resulting in a decrease in the number of broken strands of the conductor Dl (or D2). When WS/d becomes 0.4 or more, the number of broken strands becomes zero. FIG. 6 is a graph showing the relation between WS/d and contact resistance in the pressure connector-according to the present invention. In FIG. 6, the vertical line represents a contact resistance between the pressure connector and the conductor Dl (or D2), and the horizontal line represents WS/d (see also FIGS. 1 and 4). When WS/d is small, the contact resistance is small and stable because each strand of the conductor Dl (or D2) is strongly pressed by the nipping portions 7L and 7R (or 8L and 8R) . When WS/d is increased to more than 0.6, the pressure of the nipping portions 7L and 7R (or 8L and 8R) applied to each strand of the conductor Dl (or D2) is reduced, resulting in a rapid increase in the contact resistance. From the above results, the condition for ensuring no break of the strands and reducing the contact resistance is to set WS/d in the following range. 0.4 While the above preferred embodiment employs a pressure connector and two intersecting wires connected by the pressure connector, the present invention is not limited to this preferred embodiment, but the pressure connector may be used as a terminal for a single wire. [Effect of the Invention] The present invention can exhibit the following effect by the above configuration. According to the pressure connector defined in claim 1, the forked plates of the pressure connector are parallel to each other and the distance t between the forked plates is set as follows: [Exp. 3] M-p 0.4 d: diameter of said conductor (= diameter of a circumscribed circle of said conductor if it is polygonal in cross section) k: constant p: twist pitch of said conductor Rd: ratio (Sd/d) of the diameter Sd of each strand to the diameter of said conductor t: distance between said forked plates WS: distance between said nipping portions All of the strands of the conductor can be brought into contact with at least one of the forked plates, thereby reducing the contact resistance between the conductor and the pressure connector. [Explanation of Reference Numerals] 1: pressure connector 2, 3, 4, 5: forked plates (first forked portion, second forked portion, third forked portion, fourth forked portion) 7R, 7L, 8R, 8L: nipping portions (right and -left nipping portions) Cl, C2: wire Dl, D2: conductor d: diameter of the conductor El, E2: insulating cover F, P, Q: strand k: constant M: θ/π p: twist pitch of the conductor Rd: ratio of the diameter of each strand to the diameter of the conductor Sd: diameter of each strand t: distance between the opposed forked plates WS: distance between the opposed nipping portions WE CLAIM: 1. In a pressure connector (1) having a pair of opposed forked plates (2, 3, 4, 5) adapted to be pressed against a wire (6), (2) having a conductor formed by twisting a plurality of strands and an insulating cover (El, E2) covering said conductor (Dl, D2) each of said forked plates having a pair of opposed nipping portions spaced a distance smaller than the diameter of said conducto nipping said conductor. characterized in that said forked plates of said pressure connector are parallel to each other and the distance t between said forked plates is set as follows: [Exp. 1] M . p (0.5+M) . p M={ sin-1[WS/(k . d)-Rd/k]}/π 0.4 d: diameter of said conductor (= diameter of a circumscribed circle of said conductor if it is polygonal in cross section) k: constant p: twist pitch of said conductor Rd: ratio (Sd/d) of the diameter Sd of each strand to the diameter of said conductor T: distance between said forked plates WS: distance between said nipping portions 2. A pressure connector having a pair of opposed forked plates substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

Documents:

615-del-1999-abstract.pdf

615-del-1999-claims.pdf

615-del-1999-correspondence-others.pdf

615-del-1999-correspondence-po.pdf

615-del-1999-description (complete).pdf

615-del-1999-drawings.pdf

615-del-1999-form-1.pdf

615-del-1999-form-13.pdf

615-del-1999-form-19.pdf

615-del-1999-form-2.pdf

615-del-1999-form-3.pdf

615-del-1999-form-4.pdf

615-del-1999-form-6.pdf

615-del-1999-gpa.pdf

615-del-1999-petition-137.pdf

615-del-1999-petition-138.pdf

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