Surface mount connector

The surface mounted connector (50) comprises a housing (60), a number of contacts (70) and an arranging beam (80). The housing (60) is mounted on the base board, and the arranging beam (80) is inserted in the guiding grooves (67) made in the mounting legs (66) located at both ends of the narrow and long body (61). When the arranging beam (80) is inserted in place, it arrays the soldering tails (72) and (74) of the contacts (70) so that they become located in one plane. It is also preferable that the beam press the soldering tails to the pads of the base board.

FIELD OF THE INVENTION 
This invention relates to electrical connectors, especially to surface 
mounted connectors having a number of contacts or terminals which are 
connected by soldering to the pads of the circuit boards using surface 
mounting technology. 
BACKGROUND OF THE INVENTION 
Recent trends in electronic devices and electronic equipment call for 
portability and miniaturization (that is for light and small-size 
devices). In order to attain the miniaturization goals and to improve 
serviceability, not only active and passive parts, but also 
electromechanical elements (such as connectors and switches) undergo 
considerable improvements, especially in the field of home electronics. 
SMT-type elements are especially effective for these purposes and they are 
widely used in the devices where small size and high mounting density are 
especially important. As it is well known in the art, the surface mounting 
technology comprises applying a layer of soldering cream on the pads of 
the base boards or printed circuit boards to which terminals or soldering 
tails of electronic elements are pressed against the pads. After that, the 
pads are heated (for example by infra red radiation) to a temperature 
above the melting point of the solder, thus soldering the two elements 
together. 
An example of a conventional surface mounted connector (below, SMT 
connector) can be found in the Japanese patent publication No. 90-28236 
related to U.S. Pat. No. 4,583,807 filed by AMP Incorporated. This 
connector has a narrow long housing with several rows of contacts which 
are fixed to the base board. Soldering tails of these contacts are bent in 
such a manner that they form a surface coincident with that of the 
soldering pads formed on the base board. However, with an increase in the 
number of contacts and in their density, it becomes difficult to keep all 
soldering sections of the soldering tails in one plane. In addition, there 
is danger that the contacts will be deformed during the handling of the 
connectors manually or by means of robotics arms. 
A solution making it possible to eliminate this disadvantage which 
comprises the use of a part determining the position of the soldering 
tails to align them with the soldering pads of the base board is known in 
the art. An example of such a solution can be found in the Japanese patent 
publication No. 89-279581 related to U.S. Pat. No. 4,583,807 filed by AMP 
Incorporated. In this specific example, soldering tails of contacts 
arrayed in two rows are bent in a certain configuration as shown in FIGS. 
5 and 6. 
This conventional SMT connector comprises a housing 10 and two rows of 
contacts 11 inserted in the contact channels 14 provided in the housing. 
Part 21 restricting soldering tails is inserted in the recesses 25 made in 
the opposite end walls 16 in such a manner that it (the part 21) can move. 
This part 21 restricting the soldering tails has one row of the openings 
22 into which free ends of the soldering tails 18 of the lower contacts 11 
are inserted, and channels (or grooves) 23 into which free ends of the 
soldering tails 18 of the upper contacts 11 are inserted. This 
configuration makes it possible to keep all the soldering portions 19 of 
the soldering tails 18 of the contacts 11 aligned with the soldering pads 
30 of the base board. 
However, the assembly of the SMT connector shown in FIGS. 5 and 6 
represents certain difficulties. The insertion of the soldering tails 18 
of the lower row contacts 11 into the openings 22 of the housing 10 and 
the correct placement of the soldering tails 18 of the upper row contacts 
11 in the channels 23 made in the bottom of the part 21 restricting 
movement of the soldering tails becomes an extremely difficult, 
time-consuming operation, especially with an increase in the number of the 
soldering tails or in their density (in other words, in the SMT connectors 
intended for miniaturized devices having a high density of element 
mounting). 
Therefore, the purpose of this invention is to offer an SMT connector in 
which it is possible to maintain coplanarity of the soldering tails of a 
number of contacts and, at the same time, to provide appropriate pressure 
on the soldering tails when they are pressed against the soldering pads of 
the base board during soldering operation. 
Another purpose of this invention is to offer an SMT connector which 
facilitates mounting operations by making it unnecessary to pay too much 
attention to the handling of the connectors.

DETAILED DESCRIPTION OF THE INVENTION 
The SMT connector 50 comprises a narrow long housing 60, contacts 70 
arrayed in two rows and an arranging beam 80 which is provided for 
maintaining coplanarity of the contacts. As shown by a dotted line in FIG. 
3, the SMT connector 50 is fixed to a base board 90 having a number 
soldering pads (not shown in the drawing) to which soldering tails of 
contacts 70 are soldered. 
The housing 60 has a narrow and long body 61 with a front surface 62 and a 
back surface 63. At both ends of this body 61, flanges 64 are provided 
with openings 65 for the insertion of mounting bolts or other fixture. At 
the inside surface of the body 61, there are legs (or protrusions) 66 
having guiding grooves or recesses 67. The housing 60 is preferably made 
as a single unit of nylon, a liquid-crystal polymer or other suitable 
engineering plastic by conventional molding. Contacts or terminals 70 are 
either pressed into the contact-insertion openings 69 made in two rows in 
the body 61 of the housing 60 and extending from the front surface 62 to 
the back surface 61 or secured by insert molding method. All contacts 70 
include a contact post 71, which extends from the front surface 62 of the 
body 63 of the housing 60 and makes connection with a receptacle contact 
of a matching connector (not shown in the drawing), and of a soldering 
tail which extends from the back surface 63. The connector according to 
this invention may also have a protective shroud surrounding the contact 
posts 71 of the contacts 70 made along the periphery of the front surface 
62 of the body 61 of the housing 60 (this feature is not depicted in the 
FIGS. 1 through 4). As it is known in the art, in addition to protection 
of the contact posts 71 of the contacts 70, this shroud may also play the 
role of a polarizing and locking element for proper and reliable 
connection with a matching connector. The contacts 70 are usually made 
from a 0.5 mm thick copper alloy sheet by stamping and forming. The 
soldering tails of the contacts 70 include flat soldering sections 72, 74 
and inclined transitional (or intermediate) sections 73. 
The arranging beam 80 is usually made by molding of the same material as 
the housing 60. In this specific embodiment, the arranging beam 80 has the 
main body 81 and lugs 84 located at both ends. The bottom 82 of the body 
81 can be either flat or it can have a tapered section 86 at its front end 
to make its insertion easier. At the bottom 82 of the arranging beam 80', 
shallow grooves 83 corresponding to the soldering tails 72 and 74 of the 
contacts 70 may be made to keep adjacent soldering tails 72 and 74 at a 
uniform pitch from each other, see FIG. 3A. The depth of these grooves 83 
should not exceed the thickness of the soldering tails 72 and 74 so that 
the bottom surface of the soldering tails 72 and 74 is above the bottom 
surface 82 of the arranging beam 80'. 
The guiding grooves 67 of the housing 60 of the SMT connector 50 are made 
nearly parallel to the base board to which the connector is mounted. But 
if necessary they also can be made so that the back edge (the edge that is 
inserted first) is slightly higher than the front edge. In such an 
arrangement, the soldering tails 72 and 74 of the contacts 70 become 
slightly pressed against soldering pads of the base board when the 
arranging beam 80 is inserted in place. FIGS. 2 and 3 depict the operation 
when the arranging beam 80 is snapped in the housing 60, with the housing 
being mounted to the base board 90. In such a configuration, all soldering 
tails 72 and 74 can be properly soldered to the pads of the base board. It 
is preferable to provide positioning posts 68 molded at the bottom surface 
of the housing 60 which are inserted in the alignment holes provided in 
the base board 90 (as shown in the FIG. 3) thus maintaining a proper 
alignment of the soldering tails and the pads. 
Above, we gave a detailed description of a preferred embodiment of the SMT 
connector 50 according to this invention. However, it should be understood 
that this invention is not limited to this embodiment only, but it can be 
modified in various ways without deviating from its technical areas. In 
the embodiment represented in the FIGS. 1 through 4, the contacts 70 are 
arrayed in the body 61 of the housing 60 in two (upper and lower) rows. 
But this arrangement of the contacts 70 in two rows is not essential, and 
they may be arrayed in one or three or more rows. It is also possible to 
use for the attachment of the SMT connector 50 to the base board instead 
of the bolts passed through the openings made in the mounting lugs as in 
this embodiment, a flat springy metal fixture or an integral fixture 
molded together with the housing and located at its bottom. In addition, 
the lugs made at the ends of the arranging beam may be made round which 
will make it possible to rotate the beam within the guiding grooves to 
press the soldering tails against the pads. 
As follows from the above explanations, the design and mounting of the SMT 
connector according to this invention are extremely simple, and this 
design can be easily used in small connectors used for devices with a high 
mounting density. And since all the soldering tails are properly arranged 
relative to the base board, the soldering operations can be performed with 
a great precision and a high reliability. The arranging beam can be 
removed after the completion of the soldering for the purposes of visual 
inspection or correction of wrong connections. Therefore, the SMT 
connectors according to this invention are very effective for such 
applications as, for example, small hard disk drives (HDD).