Abstract:
When a pair of connectors ( 10, 30 ) are plugged with each other in a plugging direction, the contact sections ( 23, 44 A) of pairs of contact elements ( 21, 41 ) are brought into contact with each other under contact pressures in a first direction perpendicular to the plugging direction, the contact elements being spaced in a second direction perpendicular to the plugging and first directions. At least one contact sections of the pairs of contact elements are flexible in the first direction. The contact sections ( 23, 44 A) are situated in the same range in the first direction, and substantially equal numbers of the contact sections are oriented opposite in the first direction.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an electrical connector assembly consisting of a pair of connectors to be plugged into each other and electrical connectors for it. 
     2. Description of the Related Art 
     Some of the electrical connector assemblies of this type have a plurality of pairs of contact elements to be connected. When the contact element pairs of both connectors are brought into contact with each other under contact pressures in the same direction perpendicular to the plugging direction of the connectors, the combined forces of the contact pressures are applied on the housing walls. Consequently, when the wall thickness of the housings is reduced by miniaturization of the connectors, the housing walls are deformed to move the contact elements from the regular positions, resulting in the unstable and uneven contact pressures. 
     In order to avoid such a problem, it has been proposed to arrange a plurality of contact elements in a zigzag fashion for alternating the contact pressures between the contact elements. An example is disclosed in Japanese patent application Kokai No. 58-126685. 
     As shown in FIGS.  4 (A)-(C), a plurality of insertion ports  52  are provided in an elongated housing  51  along the longitudinal direction of the housing for receiving contact pins  61  of a mating connector. A retention slot  53  communicates with each of the insertion ports  52 . As best shown in FIG.  4 (B), the insertion ports  52  are positioned at the center of the thickness or height of the housing  51  while the retention slots  53  are provided at alternating upper and lower positions of the insertion ports  52 . 
     In FIG.  4 (C), a contact element  55  to be supported by the retention slot  53  has a base section  56  having flat faces and a resilient contact section  57  which is bent obliquely. The base section  56  is inserted in the retention slot  53  such that the contact section  57  is placed in the insertion port  52 . When the contact pin  61  is put into the insertion slot  52 , it makes contact with the contact section  57 . In this way, all the contact pins  61  make contact with the upper and lower contact sections  57  alternately. 
     Consequently, the housing  51  receives upward and downward contact pressures by the contact elements  55  provided above and below the insertion ports  52 , respectively. If the housing walls are satisfactorily rigid and the upper and lower contact elements are substantially equal in number, then the above contact pressures are offset. 
     However, the above connectors are bulky and has the following disadvantages. Since the contact elements are arranged in the zigzag fashion, the housing wall on the side where there is no contact element is thick, resulting in the large or thick connector. In addition, the contact elements extend in the longitudinal direction of the housing, resulting in the large or wide housing. 
     SUMMARY OF THE INVENTION 
     Accordingly, it is an object of the invention to provide a thin and narrow electrical connector assembly which receives a reduced load of contact pressures and an electrical connector for the assembly. 
     According to the invention there is provided an electrical connector assembly consisting of a pair of first and second electrical connectors, each comprising a plurality of first contact elements having first contact sections brought into contact with second contact sections of second contact elements for the other electrical connector under contact pressures in a first direction perpendicular to a plugging direction of the electrical connectors, the first and second contact elements being arranged at intervals in a second direction perpendicular to the first direction, at least one of the first and second contact sections being flexible in the first direction. 
     According to the invention, the first and second contact sections are situated in the same range in the first direction, and substantially equal numbers of first and second contact sections are oriented opposite in the first direction. The contact pressures upon the contact sections are canceled out so that little load is applied to the housing. The contact sections are situated in the same range in the first direction so that the thickness of housing walls can be minimized. The first and second contact elements are oriented alternately opposite in the first direction. 
     The contact elements are made of a metal sheet and have flat surfaces which extend in the first direction so that the contact sections have a large area in the first direction, resulting in the high strength of the contact elements and the thin walls of the housing between adjacent contact elements, making it possible to reduce the thickness of upper and lower walls of the housing. Each contact element comprises a base section which extends from each the contact section and does not exceed a maximum height of the contact element in the first direction, the base section having a projection for engagement with a housing of the electrical connector, resulting in the compact connector in the first direction. The first contact sections may be flexible, and the second contact sections of the second connector are not flexed in the first direction by the first contact sections which are flexible. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a top plan view of an electrical connector assembly prior to plugging; 
     FIG.  2 (A) is a sectional view of the electrical connector assembly taken along one pair of contact elements; 
     FIG.  2 (B) is a sectional view of part of the electrical connector assembly taken along another pair of contact elements adjacent to the above pair of contact elements; 
     FIG.  3 (A) is a sectional view taken along III—III of FIG.  2 (A), with the peripheral structure omitted, wherein a plurality of pairs of contact elements are arranged alternately upside down; 
     FIG.  3 (B) is a section view taken along III—III of FIG.  2 (A), with the peripheral structure omitted, wherein a plurality of pairs of contact elements are arranged alternately upside down in sets of two. 
     FIG.  4 (A) is a sectional view of a conventional electrical connector taken in a direction wherein the contact element of a mating connector is inserted; 
     FIG.  4 (B) is a sectional view taken along line B—B of FIG.  4 (A); and 
     FIG.  4 (C) is a perspective view of a contact element for the conventional electrical connector. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Embodiments of the invention will now be described with reference to FIGS. 1-3. 
     A connector assembly consists of a pair of connectors  10  and  30  to be connected. The connector  10  comprises a housing body  11  and a press member  12 , which are made of a dielectric material, a plurality of contact elements  21  and a metal case  29  (FIG.  2 (A)) of a metal sheet. The housing body  11  has an elongated body section  13 , a pair of support arms  14  extending rearwardly from opposite ends of the body section  13 , and a pair of extension sections  15  extending forwardly from the ends of the body section  13 . A plurality of contact elements  21  extend through the body section  13  at regular intervals. The press member  12  is pivoted to the support arms  14  with shafts  16  for rotation about an axis  16 A behind the body section  13 . A pair of projections  17  are provided on sides of the press member  12  for engagement with edges of the support arms  14  to lock the press member  12  at the closed position as shown in FIGS. 1 and 2. 
     Each extension section  15  has a flange  15 A and is fitted in the other connector  30 . The other connector  30  has a housing body  30  of a dielectric material and a plurality of contact elements  41  of a metal sheet. The housing body  31  has an elongated body section  32  and a pair of arm sections  33  extending forwardly from opposite ends of the body section  32  to form a pair of receiving cavities  34  between the arm sections  33  and the body section  32  for receiving the extension sections  15  of the connector  10 . A metal member  35  covers each arm section  33  and has a resilient piece  35 B with a projection  35 A inside the receiving cavity  34 . Also, it has a connection section  35 C to be soldered to a board for connection. 
     As shown in FIGS.  2 (A) and (B), when the connectors  10  and  30  are plugged into each other, the contact elements  21  and  41  of the connectors  10  and  30  are brought into contact with each other. A plurality of retention slits  18  are provided in the body section  13  of the connector  10  for receiving the flat contact elements  21 . Each contact element  21  is made of a metal sheet and has flat surfaces of the sheet. It has a base section  22  to be press fitted in the retention slit  18 , a contact arm  23  extending forwardly from the base section  22 , and upper and lower legs  24  and  25  which extend rearwardly from the base section  22  forming a U-shape. A projection  22 A is provided on the lower edge of the base section  22  for securing the base section  22  in the retention slit  18 . A shaft section  26 , which has a circular edge, is provided at the end of the upper leg  24 . The center of the circular edges is aligned with the axis  16 A of the shaft  16  for the press member  12 . The lower leg  25  is flexible in the vertical direction and has a pair of triangular contact projections  27 . 
     The press member  12  has a cylindrical bearing face  12 A for rotation about the comb-like shaft formed by the circular edges of the contact elements  21 . The press member  12  has a plurality of receiving grooves  12 B for receiving cables C and a pressure section  12 C at a position opposed to the contact sections  27  of the contact elements  21 . The press member  12  is rotatable about the shaft sections  26  between the closed position shown by a solid line and the open position shown by a phantom line. 
     The housing body  11  is fitted in the metal case  29  which has a plugging section  29 A projecting forwardly from the body section  13  and a cable guiding section  29 B extending rearwardly and being folded back for guiding the cables C. A plurality of retention slits  36  are provided in the body section  32  of the connector  30  at positions corresponding to the retention slits  18  of the connector  10 . Each contact element  41  is made of a metal sheet in the same manner as that of the contact elements  21 . It has a base section  42  to be press fitted in the retention slit  36 , a connection section  43  to be connected to a circuit board P, and a resilient contact arm  44  extending forwardly from the base section  42 . An arced contact portions  44 A is provided on the front end of the contact arm  44 . A projection  42 A is provided on the top edge of the base section  42  for securing the base section in the retention slit  18 . 
     The connector  30  is fitted into the plugging section  29 A of the connector  10 . The connectors  10  and  30  form a plurality of pairs of contact elements  21  and  41 . As shown in FIGS.  2 (A) and  2 (B), and  3 (A), the contact sections  23  and  44 A of the contact elements  21  and  41  are arranged alternately upper and lower positions. That is, the contact sections  23  and  44 A of the contact elements  21  and  41  are at the lower and upper positions, respectively, in FIG.  2 (A) while they are at the upper and lower positions, respectively, in FIG.  3 (A). 
     As best shown in FIG.  3 (A), such arrangements appear alternately. Alternatively, as shown in  3 (B), a plurality of sets of two contact elements are arranged alternately. In essence, it is only necessary that substantially equal numbers of pairs of contact elements be arranged alternately at upper and lower positions for even distribution of contact pressures. 
     How to assemble these connectors will be described. 
     (1) The press member  12  is brought to the open position as shown by the phantom line in FIG.  2 (A), respective cables C are placed in the receiving grooves  12 B, and the press member  12  is rotated to the closed position as shown by the solid line in FIG.  2 (A) so that the press member  12  presses the cables C toward the contact sections  27  of the contact elements  21 , bringing the contact sections  27  into contact with the core wires of the cables C by insulation displacement. 
     (2) Then, the metal case  29  is moved toward the housing body  11  until it hits the flanges  15 A of the extension sections  15  so that the housing body  11  is fitted in the metal case  29  while not only opening of the press member  12  is prevented but also the shield wires C 1  of the cables C are held by the guiding sections  29 B. 
     (3) The other connector  30  is then plugged into the connector  10  so that the housing body  31  of the connector  30  is supported by the plugging section  29 A of the metal case  29  while not only the extension sections  15  of the connector  10  are fitted in the receiving cavities  34  of the connector  30  but also the projections  35 A are brought into contact with part of the metal case  29 . The shield wires C 1  of the cables C are connected to the board via the metal case  29  and the metal member  35 . 
     (4) As shown in FIGS.  2 (A) and (B), the contact sections  23  and  44 A of the connectors  10  and  30  are brought into contact with each other with contact pressures in the vertical direction. The contact arms  44  with the contact portions  44 A are flexed in the vertical direction so that the contact pressures are not transmitted to the thin front walls of the housing but borne by the thick walls via the base sections  42  of the contact elements  41 . 
     The contact pressures borne by the contact sections  23  of the contact elements  21  are transmitted to the housing because the contact sections  23  are in contact with the inside walls of the retention slits  36 . Consequently, the contact sections  23  exert contact pressures onto the upper and lower thin front walls of the housing alternately so that the contact pressure borne by each front wall is a half of the total force. In addition, the contact pressures are borne alternately by the upper and lower walls equally so that they cancel out each other. It is preferred that the contact positions of pairs of adjacent contact elements are at the same position relative to each other. It is noted that the invention is not limited to the illustrated embodiment only. For example, pairs of contact elements may be both flexible. 
     According to the invention, the pairs of contact elements of two connectors are arranged not only in the same range in the direction of contact pressure but also in the manner that the contact sections face in opposite directions so that the contact pressures are canceled out, thus remarkably reducing the load on the housing, making it possible to minimize the wall thickness of the housing around the above range and thus the housing itself.