Apparatus for holding electrical or electronic components during the application of solder

A carrier for holding SOIC packages during the application of solder to their leads, the carrier including a frame provided with an end plate (17) with mounting lugs (20). On each lug (20) is mounted an upper U-shaped member (1) and a lower U-shaped elongate member (8) with the respective legs (3) and (10) of the members projecting downwardly. The legs (10) are disposed within the legs (3) but extend further and terminate at outwardly turned ends (11). Adjacent assemblies of the members (1) and (8) define a track (T) therebetween for a line of SOIC packages (24) whose leads (26) rest on end portions (11), and which are restricted against upward movement by the ends (4) of legs (3).

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to apparatus for holding electrical or electronic 
components, particularly during the application of solder. The invention 
is particularly concerned with the holding of integrated circit packages 
while their leads are being coated with solder, for example in, wave 
soldering apparatus. Such a coating is applied before the packages are 
inserted into circuit boards or suitable holders and, if necessary, 
soldered in place. 
2. Description of the Prior Art 
In the U.S. Pat. No. 4,677,937 there is disclosed a carrier for a plurality 
of electrical or electronic components, particularly for use as outlined 
above, that includes a frame in which there are provided a plurality of 
parallel tracks for receiving the components. The tracks are formed by a 
plurality of parallel, laterally spaced, axially extending upper support 
members, each of which defines a pair of parallel axially extending upper 
rails having downwardly facing portions. The tracks also include a 
plurality of parallel, laterally spaced, axially extending lower support 
members aligned with the upper support members, each of the lower support 
members defining a pair of parallel, axially extending lower rails having 
upwardly facing portions. Each track is defined by four rails and is 
situated between two adjacent upper support members and their aligned 
lower support members. 
Such a carrier has been found to be extremely effective, providing easy 
access for solder to the components, easy loading and unloading of the 
components, and the ability to withstand the temperature changes 
encountered during use. 
SUMMARY OF THE INVENTION 
The present invention relates to a modification of such an arrangement 
which has been designed particularly, but not exclusively, for handling 
smaller sizes of integrated circuit packages, such as SOIC (Small Outline 
Integrated Circuit) packs which are usually surface mounted on boards. 
In accordance with one aspect of the carrier of the invention, each upper 
support member is of substantially "U"-section with its legs directed 
downwardly, and each lower support member is also of substantially 
"U"-section with its legs projecting downwardly and beyond the ends of the 
legs of its aligned upper support member but being spaced inwardly 
thereof. The lower support member have end regions of its legs directed 
outwardly so as to provide portions which face generally upwardly. 
With such an arrangement, the four rails of each track, within which the 
components are to be received, are defined by the legs of two adjacent 
upper "U"-shaped support members and by the outwardly directed end regions 
of the legs of two adjacent lower "U"-shaped support members. It will be 
appreciated that viewed from the center of the track, these end regions 
are directed inwardly. 
Thus, the components will run along the upwardly facing portions of the 
legs of the lower support members and will be restricted in terms of 
upward movement by the downwardly directed legs of the upper support 
member. The legs of the lower support members will restrict lateral 
movement of the components. 
In such a system, the components will generally rest on their leads which 
will engage the upwardly facing portions of the legs of the lower support 
members. In the case of SOIC's, they will rest on laterally directed 
portions of the leads since the components are designed for surface 
mounting on boards. 
Such an arrangement differs from that shown in the U.S. Pat. No. 4,677,937, 
where the leads are free from the tracks. However, access to solder is 
still adequate since the components will float up when the carrier is 
dipped in solder, so that the leads will be adequately exposed. 
With the arrangement described, it is not necessary for the upper and lower 
support members to be spaced vertically by any great distance, since they 
are both downwardly facing "U"-shaped members, one within the other. 
Indeed they can be positioned with one immediately below the other, and 
preferably even in contact therewith. This provides a further advantage 
since they can be mounted together on a single mounting, i.e. with a 
single lug engaging in a slot in each of them. As is disclosed in the U.S. 
Pat. No. 4,677,937 it is desirable to mount the support members by means 
of lug/slot arrangements to allow for thermal expansion. It might even be 
possible, e.g. by aperturing the upper sppport member, to mount the lower 
support member so that it projects through the upper support member, 
although this will involve certain modifications at the ends where the 
support members are located. 
As is further disclosed in the U.S. Pat. No. 4,677,937 the support members 
may be provided with apertures along their length to reduce the amount of 
material. In one preferred arrangement, either or each support member may 
now have a slot along its entire length. Cross-members may be provided at 
intervals to reinforce the support member and e.g. resist thermal 
deformation. If desired, however, the members could be provided without 
any such slot. 
The general layout of the apparatus and the manner in which it is used be 
similar to those disclosed in the U.S. Pat. No. 4,677,937.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring now in detail to the drawings, in FIG. 1 there is shown an 
elongate upper support member 1 formed from a suitable material such as 
steel or titanium which will withstand the heat of immersion in solder 
without undue distortion and will be hard wearing. The member 1 is in the 
form of an elongate inverted "U" with an upper surface 2 and downwardly 
directed legs 3 having end portions 4. An elongate slot 5 is formed in the 
upper surface 2, to reduce the quantity of material. At either end of the 
member, in the upper surface 2, are formed apertures 6 having reduced size 
end portions 7. These apertures are used to locate the support member in 
the carrier. 
In FIG. 2 there is shown an elongate lower member 8 likewise formed from a 
suitable material such as steel or titanium. The member 8 is in the form 
of an elongate inverted "U" with an upper surface 9 and downwardly 
directed legs 10 having end portions 11 which are bent outwardly so as to 
provide upwardly facing surfaces or portions 12. An elongate slot 13 is 
provided in the upper surface 9, as with the upper support member 1. 
Similarly apertures 14 are provided at either end of the surface 9, having 
reduced end portions 15 in the same manner as apertures 6 in the upper 
support member 1. The upper surface 9 is narrower than the surface 2 of 
the upper support member 1, and the legs 10 are longer than the legs 3. 
FIG. 3 shows an end view of an assembled carrier 16 using five upper 
members 1 and five lower members 8 so as to provide four tracks T. 
Although only one end is shown and descrbed, the other end is identical. 
The carrier has a frame defined by an end plate 17 and two side plates 18 
with handle portions 19. On the end plate 17 are provided five mounting 
lugs 20. On each lug is mounted an upper support member 1 and, directly 
underneath and in contact with it, a lower support member 8 which is 
within the upper support member 1 but has its legs 10 projecting 
downwardly beyond the legs 3 of the upper support member 1. Each lug 20 is 
joined to the main body of the end plate 17 by a reduced size portion 21 
which passes through the end portions 7 and 15 of the apertures 6 and 14 
in the upper and lower support members 1 and 8, respectively. This is 
shown more clearly in FIGS. 4 and 5. Assembly is effected by passing the 
lug 20 through the larger portions of the apertures 6 and 14, and then 
sliding the support members. The tracks T are defined between each pair of 
aligned upper and lower support members 1 and 8. 
A vertically movable gate 22 is provided on the end plate 17, having 
downwardly facing projections 23 which block the tracks T when the gate is 
lowered. With the gate raised, components can be inserted into the tracks 
T, and with it lowered the components will be kept in the tracks. The 
number of components accommodated will depend on their size and the length 
of the tracks T. 
As mentioned above, the ends of the carrier are identical, so that 
components can be inserted into and removed from the tracks T at either 
end. 
As shown in the enlarged view of FIG. 4, an "SOIC" integrated circuit pack 
24 has been inserted into one of the tracks T. The pack has a body 25 and 
leads 26 which flatten out so as to assist in surface mounting on a 
circuit board. In the track T, the SOIC pack rests on upwardly facing 
surfaces 12 by means of its leads 26. These surfaces, being angled to the 
vertical, also restrict sideways movement of the pack 25 as can the main 
portions of the legs 10. Upwards movement of the SOIC pack is restricted 
by the end portions 4 of the upper support member, although there is 
clearance. Thus, when the carrier is immersed in solder the component 25 
can float up a short way so as to permit the leads 26 to lift free of 
surfaces 12 to ensure adequate access for the solder. 
The construction of the lugs 20 is shown more clearly in FIG. 5 which 
illustrates how the rectangular lugs are joined to the main body of end 
plate 17 by the reduced portions 21. 
It will be appreciated that many variations and modifications of the 
carrier and its components may be made while still retaining at least some 
of the novel concepts and structures disclosed herein and the 
corresponding advantages. 
In use, the carriers will generally be handled e.g. as disclosed in the 
U.S. Pat. No. 4,677,937. However, it will be appreciated that the carrier 
may be handled differently and may also be used in fields other than 
soldering.