Jacks formed by die casting

A jack assembly is provided in which the central body of the assembly includes integrally cast posts for aligning and securing follower springs, wiper springs and spacers. To assemble the jack, the follower springs, wiper springs and spacers are stacked onto the posts and then secured with a pushnut that engages the posts with a friction fit, avoiding separation from the central body.

FIELD OF THE INVENTION 
The invention relates generally to a jack assembly used in electrical 
panels for connecting circuits. More specifically, the invention relates 
to a jack having a central component that is die cast to reduce the number 
of parts and the labor required to manufacture the jack. 
BACKGROUND OF THE INVENTION 
With the recent explosion in the number of computer networks, cable 
television networks, the internet, and other digital networks, the need 
for interconnection units has grown similarly. A common unit in use is a 
jack panel that is part of manual digital cross-connect (DSX) frame 
systems used for cross-connection, temporary patching, and monitoring of 
digital circuits conforming to the DS-1 or DS-1C transmission standards. 
An example of such a jack panel is the BANTAM DSX-1/1C Jack Panel. A 
standard panel contains 168 jacks, which can be interconnected in 
literally thousands of combinations. 
The current jacks used in the panels have anywhere from 17 to 21 parts per 
jack that are held together with machine screws and nuts. These jacks 
require significant hand assembly. Both of these features make the current 
jacks costly and inefficient to manufacture. 
Manufacture of jacks of past and current designs would be difficult to 
automate as they involve the assembly of posts, screws and nuts to secure 
stacks of springs and spacers. For example, U.S. Pat. No. 4,861,281 to 
Warner discloses a jack in which the posts, springs, spacers and nuts must 
be hand assembled. With reference generally to FIG. 5 of the '281 patent, 
the prior art shows a jack unit having a case frame structure 42 including 
support beams 60 and 64. The support beams have holes 62 and 66 through 
which bolts 80 are inserted and extend for securing the spacers and 
springs. As seen in FIG. 2 of the '281 patent, the various springs (e.g., 
72, 76) and spacers 78 are mounted on the bolts in order, and then they 
are secured in place by nuts placed on the ends of the bolts. 
Before the nuts are tightened on the bolts in the '281 patent, the various 
springs and spacers are not secured to the bolts, nor are the bolts 
secured to the support beams. This makes assembly difficult. The '281 
patent disclosure relies on the multiple support beams to avoid any 
twisting or loosening of the various components during use. However, the 
rigidity and integrity of the overall unit is solely dependent on the nuts 
and bolts being tightly secured and having a tight clearance with the 
holes in the support beams. 
SUMMARY OF THE INVENTION 
In view of the foregoing deficiencies of the prior art, it is an object of 
the present invention to provide an improved jack assembly. 
It is another object of the present invention to provide a jack assembly 
with a cast post to provide an assembly fixture to position and retain the 
springs and spacers during assembly. 
It is a further object of the present invention to provide a jack whose 
assembly can be easily automated. 
It is yet another object of the present invention to provide a jack 
assembly in which the springs and spacers are held on the posts by 
pushnuts for ease of assembly. 
It is a still further object of the present invention to provide a jack 
assembly in which dual posts provide resistance to rotation during 
mechanical and thermal cycling, increasing the reliability of the 
assembly. 
It is a yet further object of the present invention to provide a dual 
pushnut for securing the springs and spacers to the dual cast posts of the 
jack assembly. 
It is still another object of the present invention to provide a jack 
assembly that is formed with fewer unique parts to reduce automation, 
design and inventory costs and that may be manufactured at a lower cost 
with overall higher quality, consistency and reliability. 
In an illustrative embodiment of the present invention, a jack assembly is 
provided in which the central body of the assembly includes integrally 
cast posts for aligning and securing the jack springs and spacers. To 
assemble the jack, the springs and spacers are stacked onto the posts and 
then secured with a pushnut that engages the posts with a friction fit, 
avoiding separation from the central body.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring now to FIG. 1, a jack assembly 10 according to the preferred 
embodiment of the invention is shown. In overview, the jack assembly 10 is 
comprised of a central body 12 having an elongated midsection 14. Four 
posts 16 extend from the midsection 14 to support the follower springs 18, 
wiper springs 20, and spacers 22, 52 that make up the functional portion 
of the jack assembly 10. A pushnut 44 is mounted on top of the stack of 
springs 18, wiper springs 20, and spacers 22, 52 to retain them on the 
posts 16. Two posts 16 preferably extend from each of the top and bottom 
surfaces of the midsection 14. According to the invention, the four posts 
16 are cast integrally with the central body 12. For the purposes of this 
specification, the posts 16 extending above and below the midsection are 
considered to define a vertical plane. It is to be understood that the 
jack assembly 10 can easily be mounted with the posts 16 horizontal or at 
any angle with respect to horizontal, but for reference purposes, the 
posts 16 define a vertical plane. It is also not necessary that all of the 
posts 16 lie in a plane, although it is preferred that each pair of posts 
16 extending from the same side of the midsection 14 be generally 
parallel. There also may be any number of posts 16, although it is 
preferred that there be at least two. 
Various follower springs 18, wiper springs 20, and spacers 22 are 
interleaved on the posts 16. Each of the follower springs 18, wiper 
springs 20, and spacers 22, 52 includes at least two apertures 24 to 
receive the posts 16 on which they are mounted. The spacers 22 and pylon 
spacers 52 serve to position the follower springs 18 and wiper springs 20 
and to electrically insulate the follower spring 18 and wiper spring 20 
pairs from each other and from the central body 12. 
The central body 12 of the assembly also includes a front flange 26 with 
barrels 28 for receiving the plugs (not shown) that are inserted into the 
jack assembly 10 to make a connection with the wiper springs 20. The front 
flange 26 is preferably mounted along the vertical axis, perpendicular to 
the midsection 14 and parallel to the posts 16. The front flange 26 may 
advantageously be cast integrally with the midsection 14 of the central 
body 12, or may be attached during assembly without significant detriment 
and without departing from the invention. 
The midsection 14 of the central body 12 is generally shaped as a 
rectangular prism. This provides a smooth, planar top and bottom surface 
30, 32 for the first follower spring 18 or spacer 22 mounted on the posts 
16. If these surfaces 30, 32 of the midsection 14 were not planar, there 
could be instability in the stack of follower springs 18, wiper springs 
20, and spacers 22, 52 when mounted. The midsection 14 of the central body 
12 extends from the area in which the posts are attached to a preferably 
narrowed transition area 34 where it is attached to the front panel 26. 
The narrowed transition area 34 of the central body 12 allows the wiper 
springs 20 to deflect when plugs are inserted into the jacks without 
hitting the central body. This also provides clearance for the follower 
springs 18 and wiper springs 20 to be biased toward the central body. The 
plug can then move the follower springs 18 and wiper springs 20 away from 
the central body, causing firm continuous contact with the wiper springs 
20. 
The posts 16 are cast as one unit with the midsection 14. Each post has a 
conical shape which decreases in diameter slightly from the midsection 14 
to the end of each post 16. Referring now to FIGS. 2 and 5, at the 
attachment point between the midsection 14 and the post 16, a small 
depression 36 is cast into the midsection 14 to ensure that the first 
spring 18 or spacer 52 mounted on the posts 16 will rest flush against the 
midsection 14. The small depression also relieves any stress that may 
concentrate at the interface of posts 16 and midsection 14. The posts 16 
preferably have a nearly constant diameter over a majority of their length 
so that components at a higher elevation in the stack will have only 
slightly more misalignment with respect to the posts than do those closer 
to the central body 12. Some misalignment in a plane parallel to the 
midsection is tolerable, so long as it does not interfere with the 
functioning of the follower springs 18 and wiper springs 20 when a plug is 
inserted. All wiper springs 20, must of course remain aligned sufficiently 
to establish a connection with a plug upon insertion in jacks 28. The tip 
38 of each post 16 is preferably rounded or chamfered to assist in guiding 
the follower springs 18, wiper springs 20, and spacers 22, 52 onto the 
posts 16. This improves the ease of assembly and improves the possibility 
of automating the assembly of the jacks. 
The wiper springs 20 are preferably stamped from sheet metal. Referring now 
to FIG. 6, each wiper spring 20 is a single piece of metal that can be 
considered to have five portions, a base portion 20a that will make up 
part of the stack of follower springs 18 and spacers 22, 25, the 
connection portion 20b, extending away from the front flange 26 and 
including some formation for connecting the wiper spring 20 to the 
remaining circuitry of the panel (not shown); the spring contact portion 
20c, which extends from the stack toward the front flange 26 and includes 
a contact 20e; and the portion 20d that wipes against the plug. The distal 
end 40 of the contact portion 20d is curved to allow the plug to slide by 
it and to provide a single firm contact point with the plug. The base 
portion 20a includes the two holes 24 to receive the posts. Preferably, 
the two holes 24 are sized, chamfered or radiused to be able to easily 
accept the diameter of the sleeves 56 of the pylon spacer 52 while 
maintaining alignment in the stack. 
Referring now to FIG. 10, the follower springs 18 are also stamped as a 
single piece of sheet metal and have four main portions: the base portion 
18a, similar to the base portion 20a of the contacts, the connection 
portion 18b, similar to 20b; and the contact portion 18c, which includes 
contact 18d similar to 20c and 20e, and which extends from the base 
portion 18a toward the front flange 26. The thickness of spacer 22 
together with the height of contacts 18d and 20e form a conductive path 
when assembled. The conductive path is opened when a plug is inserted. The 
base portion 18a of the springs includes two holes 24 to receive the 
posts. Preferably, the two holes are sized to be able to easily accept the 
diameter of the sleeves 56. 
Referring now to FIG. 11, the spacers 22 are preferably formed as 
rectangular pieces, all being sized to reduce the number of unique parts 
needed in a jack assembly. The size of the spacers 22 defines the size of 
the stack. The spacers 22 are preferably long enough in the direction of 
the midsection 14 to provide a stable platform for the follower springs 18 
and wiper springs 20 against torque due to the insertion of jacks. The 
spacers 18 also include two holes 24 to receive the posts 16. Preferably, 
the two holes are sized to be easily able to accept the diameter of the 
sleeves 56. 
Referring now to FIGS. 7-9, the pushnut 44 is preferably stamped from sheet 
metal, which may be a different material than that used to form the 
follower springs 18 and wiper springs 20, as long as that chosen material 
has adequate thickness and material properties to function as the pushnut. 
The pushnut 44 is formed with two holes 46 to receive the posts 16. Both 
holes 46, however, are stamped with tabs 48 bent slightly out of the plane 
of the pushnut 44 toward the same side of the pushnut 44. The tabs 48 are 
sized and angled so that when the pushnut 44 is mounted on the posts 16, 
the posts 16 will slightly expand the tabs 48 in elastic deformation. The 
pushnut 44 is mounted onto the posts 16 with the tabs 48 facing away from 
the midsection 14. The opposite surface 50 of the pushnut 44 is therefore 
flat and will lie against the uppermost spacer in the stack. The tabs 48 
will then maintain sufficient pressure against the posts 16 so that 
friction will prevent the pushnut 44 from moving away from the midsection 
14. Because of the angle of the tabs 48, the pushnut 44 will resist torque 
when the contacts 20 and springs 18 are loaded by an inserted plug. Torque 
will only increase the pressure of the tabs 48 on the post 16, increasing 
the friction and preventing movement. 
It is preferred that the configuration of tabs 48 on the two holes 46 be 
different. As seen in FIG. 7, the hole 46 that will receive the post 16 
closer to the front panel 26 is preferably formed with several tabs 
forming an annulus around the hole 46. This provides maximum contact 
between the tabs and the post 16. The tabs around this hole will 
experience most of the torque produced by the springs 18 and contacts 20 
being moved at their ends 40, 42 by a plug. The hole 46 away from the 
front panel 26 preferably has fewer tabs 48, such as the two shown in FIG. 
7. These tabs 48 are sufficient to resist movement and the minimal torque 
that will be experienced at that hole 46. 
Referring now to FIGS. 12 and 13, the pylon spacers 52 each include a base 
54 and two sleeves 56. The sleeves are sized and spaced apart to fit onto 
the posts and rest so that the base 54 is flush with the midsection 14. 
The sleeves prevent contact between the posts 16 and the follower springs 
18 or wiper springs 20. 
The central body 12 including the posts 16 is preferably cast from a 
zinc-aluminum alloy. Zinc-aluminum is preferred because it is easily cast, 
relatively inexpensive, yet durable and rigid enough to withstand both 
thermal and physical stresses from the cycling of tension on the follower 
springs 18 and wiper springs 20 during use. Many other substances, 
including but not limited to other metals, plastics, composites, and 
ceramics will work similarly, with the performance and costs varying 
depending on the characteristics of the material being used. The follower 
springs 18 and wiper springs 20 are preferably stamped from a conductive 
sheet metal, such as an alloy of copper. Any conductive substance with 
sufficient characteristics in terms of conductivity, elasticity, and 
durability will work similarly. The spacers 22 and pylon spacers 52 are 
preferably formed of a non-conductive plastic, such as polybutylene 
terephthalate although many non-conductive materials will work similarly. 
Assembling the jack is significantly improved compared to the prior art. 
Once the central body 12 has been cast and the follower springs 18, wiper 
springs 20, and spacers 22, 52 have been formed, assembly is accomplished 
as follows: the pylon spacers 52 are placed on the posts 16, followed by 
the follower springs 18, spacers 22 and wiper springs 20 in the desired 
order. Once the entire stack has been placed onto the posts 16, a pushnut 
44 is simply placed onto the stack and pushed down with sufficient force 
to ensure all components of the entire stack are flush with each other and 
the pushnut 44 will hold its place. The assembly is then complete. It is 
easily seen that this process can be automated. The process of the present 
invention eliminates the prior art steps of threading a bolt through holes 
in a body; holding the bolt in place while mounting the follower springs, 
wiper springs and spacers; having a nut catch the thread of the bolt; and 
then rotating the nut while holding the other end of the bolt firm to 
screw the bolt down tightly on the stack. 
Thus it can be seen that the objects and advantages of the invention are 
met by the present improved jack assembly, both in terms of assembly and 
in function. It will be understood by those skilled in the art that 
variations may be made from the preferred embodiment without departing 
from the spirit of the invention. It is also to be understood the 
foregoing embodiments have been shown and described for the purposes of 
illustration and not for the purpose of limitation, the invention being 
only limited by the claims, as follows: