T-rail printed circuit board guide and support

A printed circuit board guide and support is disclosed which provides for mounting printed circuit boards into a housing while eliminating the need for screws or a complex housing design.

BACKGROUND OF THE INVENTION 
1. Field of the invention 
The present invention pertains generally to mounting a printed circuit 
board onto a surface. 
2. Description of the Background 
Electric and electronic apparatus using printed circuit boards for mounting 
electrical components have generally required mounting the boards into 
cases to prevent mechanical damage and to provide electro-magnetic 
isolation in the form of a Faraday shield. The board must be securely 
mounted into the case and also have a stand-off to avoid any contact 
between the components mounted on the board and the case. In order to meet 
these requirements in the past has required complicated assembly parts, 
expensive cases, and laborious assembly procedures. 
Prior techniques have included using card cage type assemblies. Card cage 
assemblies typically require mounting slide guides onto the housing. The 
assembler must work inside the housing using tools and fasteners, for 
example screws and screwdrivers. An alternative is a housing design which 
is in an open position during assembly. This requires a more complicated 
housing design. That type of design complicates the assembly process and 
the manufacturability design and consequently, the cost of the housing. 
Other techniques have included fastening the board directly to the housing. 
This technique involves the same assembly constraints as the card cage 
assemblies. Assemblers must either work in a confined space in the housing 
using tools and fasteners or a relatively complicated housing must be 
designed and built which allows assembly in an open position and closes 
after assembly. 
Still another technique has been to fasten a printed circuit board onto a 
rail using screws. One prior technique was a slide member having a support 
portion and a rail portion connected thereto. The support portion has a 
threaded cavity for holding a screw, the screw being aligned through a 
hole in a printed circuit board and the threaded cavity of the support 
portion so that the printed circuit board is attached to the slide member. 
The rail portion has a slide surface and an engaging surface, the rail 
portion having a length. A claw attached to the housing received the slide 
member and guided the slide member, in order to make contact to the 
engaging surface of the rail portion, and to secure the slide member to 
the housing in all directions except along the rail portion length. The 
rail, in turn, was fastened to the housing by a claw stamped and bent from 
the housing. The claw allowed the rail to slide along the length of the 
rail and the length of the housing surface while retaining the rail from 
moving along the other two axis, side-to-side and up-and-down. This has 
limitations in that generally at least four, and usually six, screws are 
required and must be manually attached. At least two rails are needed. 
Since there are multiple rails, the rails need to be carefully aligned so 
that the rails are parallel to each other and spaced correctly in order to 
fit into the claws in the housing. 
The problem is to provide a board mounting into a housing design which 
essentially eliminates the need for assemblers to work in a limited space 
using tools and fasteners, reduce the number of parts required for 
mounting a board into a housing, and keep the housing design simple so as 
to make it easy to fabricate, and reduce its cost. 
SUMMARY OF THE INVENTION 
The present invention overcomes the limitations of the prior art by 
providing a slidable mounting arrangement for mounting an electric 
component board into a housing comprising a housing; a slide member having 
a rail connected to a support, the support arranged and constructed to 
attach to a printed circuit board, the rail having a slide surface and an 
engaging surface, the rail, also, having a length direction; a bent finger 
guide connected to the housing and making contact to the engaging surface 
of the rail portion of the slide member to secure the slide member to the 
housing in all directions except in the length direction of the rail. It 
is an objective of the invention to minimize the use of screws since the 
invention provides for designs where the gripping means or fingers can be 
incorporated into a one piece housing, the circuit board can be attached 
to the slide member outside of the housing through the use of a screwless 
assembly technique and then the assembly slid into the housing and the end 
attached to prevent the assembly from sliding along the length of the 
housing.

DETAILED DESCRIPTION 
FIG. 1 shows one solution in the prior art which provides for attachment of 
a printed circuit board into a simple housing. The printed circuit board 
10 is connected to rails 20 by screws 30. The printed circuit board may 
have a variety of electronic or electrical components 40 attached to it 
and interconnected to perform some electronic function. The assembly is 
attached to the housing 50 by grips 60. The grips 60 can be formed as part 
of the housing 10, and can even be of the same material. 
FIG. 2 shows the present invention be attached to the housing. In this 
embodiment, the rails 100 support multiple levels of printed circuit board 
by having multiple grooves 110. In this case, three levels of printed 
circuit board can be loaded into the attachment. The grooves are spaced so 
as to provide adequate clearance between the electronic components 
attached to the printed circuit boards. Wider separation is generally 
required for boards with components on both sides and for boards with 
larger size components like transformers or large capacitors. Also, the 
grooves do not all have to be equally spaced from each other. Depending on 
the particular components to be attached to any given board, that board 
may require less or more clearance than other boards to be assembled into 
the housing. The length of the grooves can vary since not all of the 
boards may have the same dimensions as depicted in the bottom groove 110. 
By properly designing and constructing different size boards, space can be 
left for other sub-assemblies or the sub-assembly connected to a cover, 
keypad, or keyboard mounted to the face of the housing 50. 
The rails 100 slide into the grips 60. There are two sets of grips for each 
mounting 120. The printed circuit boards can be loaded in the attachment 
after the attachment is located into the housing 50 by simply sliding the 
boards into place along the grooves 110 of the attachment. No assembly 
with screws is required. This eliminates the needs for screws, reducing 
material costs, and eliminates the need for screwing the printed circuit 
boards onto the attachment, reducing labor and cycle time. The preferred 
embodiment has two mountings 120, one that slides in on each side of the 
housing 50. In this way, two opposite sides of a printed circuit board can 
be supported. 
In this example, three printed circuit boards, two full-size and one 
half-size, are being supported by two mountings, each of the two rails are 
held by two sets of grips formed out of the housing material. Each 
mounting is monolithic plastic molded construction. 
FIG. 3 shows a close-up of the attachment to the housing 50. In this case, 
the grips 60 are stamped and bent from the material forming the housing 
50. The dimensions are preselected in order to allow the slide rail 
portion of the mount to slide through along the length 210 of the rail 
200, bet yet secure it from movement in the other two orthogonal 
directions. The printed circuit board 10 is supported above the rail in 
the groove 110 on the mount 120. 
FIG. 4 shows a different embodiment of the rail portion 300. The grips 60 
fit into a concave portion 310 of the rail 300. The mount 120 supports the 
printed circuit board 10 as in the other embodiments. 
FIG. 5 shows another variation of the grip design. Instead of two opposing 
grips at each point of attachment between each rail 400 nd 401 and the 
housing, the grips are arranged so that only one grip 410 is needed at 
each point adjacent rail 400 by using a grip 411 on a parallel rail 401 to 
counter the movement of both of the rails due to the printed circuit board 
10 being supported by the mounts 120 and 121. 
The foregoing description of the invention has been presented for purposes 
of illustration and description. It is not intended to be exhaustive or to 
limit the invention to the precise form disclosed, and other modifications 
and variations may be possible in light of the above teachings. The 
embodiment was chosen and described in order to best explain the 
principles of the invention and its practical application to thereby 
enable others skilled in the art to best utilize the invention in various 
embodiments and various modifications as are suited to the particular use 
contemplated. It is intended that the appended claims be construed to 
include other alternative embodiments of the invention except insofar as 
limited by the prior art.