ATE test fixture having a self-sealing vacuum skirt

In one embodiment, a skirt of an integral resilient material having a L-shaped cross-section is disclosed, and in another embodiment a skirt of an integral resilient material having a F-shaped cross-section is disclosed. The skirts are for sealing the peripheral interface defined between relatively movable electronic circuit device receiving and probe support boards of a test fixture for automatic testing equipment (ATE). The skirts preferably are of an elastomeric material. In the F-shaped embodiment, the skirt is also self-seating against the lateral edge of the probe support board.

FIELD OF THE INVENTION 
The present invention is directed to the field of automatic testing, and 
more particularly, to a novel automatic testing equipment test fixture 
having a self-sealing vacuum skirt. 
BACKGROUND OF THE INVENTION 
Vacuum actuated test fixtures, such as those in U.S. Pat. Nos. 4,598,246 
and 4,625,164, both incorporated herein by reference, are known for 
receiving electronic circuit devices to be tested, and for electrically 
interconnecting the received electronic circuit devices to automatic 
testing equipment. 
The electronic circuit devices are received on a movable receiving face 
that is resiliently supported on coil springs fastened to a stationary 
board supporting plural probes electrically connected to the automatic 
testing equipment. The peripheral interface between the movable device 
receiving face and the stationary probe support board includes a 
vacuum-tight resilient hinge comprised of a resilient sheet material, to 
which the electornic circuit device receiving face is attached. The 
peripheral boundary of the resilient sheet material is held against the 
stationary probe support board against upstanding sideboards supported off 
the probe support board. 
The retained resilient hinge interface is disadvantageous in several 
respects. It requires separate retainers and sideboards so that the 
construction is costly insofar as it requires multiple components that 
must be severally purchased and inventoried. The construction furthermore 
is expensive from a personnel point of view. It is necessary to adhere the 
resilient skirt to the device receiving face, and to retain it against the 
sideboards, which represents significant time and labor. In addition, the 
upstanding sideboard are supported on the probe board with a plurality of 
machine screws and require air-tight sealing after installation. Their 
structure must be disassembled to drill the probe plate, and then 
reassembled, required considerable time labor. 
SUMMARY OF THE INVENTION 
In accordance with a principal object of the present invention, a unitary 
resilient skirt for sealing the peripheral interface defined between 
automatic testing equipment (ATE) movable circuit receiving and stationary 
probe support boards is provided. In one embodiment, the skirt has an 
L-shaped cross section, one leg of which is in sealing relation with the 
fixed probe support board and the other leg of which is in sealing 
relation with the movable circuit receiving face. The L-shaped skirt in 
the preferred embodiment is constructed out of a spongy elastomer. In a 
second embodiment, the sealing skirt has an F-shaped cross-section, the 
base and the lower arm of which is in a self-seating sealing relation with 
the stationary probe support board, and the head or the top arm of which 
is in sealing relation to the movable device receiving face. In the 
F-shaped embodiment, a solid elastomer can be used. In both embodiments, 
the integral nature of the self-sealing vacuum skirts not only achieve 
significantly improved materials and labor savings and present a more 
satisfying appearance to the eye but also achieve highly effective vacuum 
seals during testing head operation.

DETAILED DESCRIPTION OF THE INVENTION 
Referring now to FIG. 1, generally designated at 10 is a partial sectional 
diagram of the novel ATE test fixture having a self-sealing vacuum skirt 
according to the present invention. The fixture 10 includes an electronic 
circuit board receiving face 12 mounted for reciprocating motion to a 
stationary probe support board 14 via a plurality of circumferentially 
disposed coil springs 16 and vertical registration pins (not shown) to 
prevent motion in any lateral direction. The probe support board 14 
includes a plurality of upstanding spring-loaded contacts, preferably POGO 
contacts, not shown, that are fastened about the probe support board 
defining an intended contact array pattern. The contacts are electrically 
connected to automatic testing equipment. 
An integral self-sealing vacuum skirt generally designated 18 is provided 
at and along the peripheral interface defined between the movable 
electronic circuit device receiving face 12 and the stationary probe 
support board 14. The skirt 18 includes a sealing leg 20 that seals the 
edge of the movable face 12 for that portion of the surface thereof 
adjacent its peripheral boundary. The skirt 18 further includes a 
stationary probe support board sealing leg 22 that is seated on the 
peripheral ledge of the stationary probe support board 14 and is in a 
sealing relation therewith. The legs 20, 22 have an L-shaped 
cross-section. Stops 24 are provided on the board 14 for limiting the 
deflection of the movable device receiving face 12. A vacuum pump, not 
shown, is coupled to the chamber defined by and between the receiving face 
12, the skirt 18 and the probe support board 14 for evacuating the chamber 
and thereby inducing the pressure of the atmosphere to overcome the 
resilience of the springs 16 thereby urging the face 12 downwardly against 
the stops 24, as seen in FIG. 2. The vacuum acts on the legs 20, 22 of the 
skirt 18, drawing the corresponding interfaces thereof together into a 
sealing, vacuum-tight relationship with the confronting surfaces of the 
members 12, 14. The material of the skirt 18 is preferably selected to be 
a spongy elastomer, where, upon vacuum release, the face 12 and therewith 
the skirt 18 return to their unactuated conditions, all the while 
maintaining the vacuum seals, as illustrated in FIG. 1. 
Referring now to FIG. 3, generally designated at 30 is another embodiment 
of the ATE test fixture having a self-sealing vacuum skirt according to 
the present invention. The fixture 30 is substantially identical to the 
fixture 10 of the FIGS. 1 and 2 embodiment, except a differently shaped 
self-sealing vacuum skirt generally designated 32 is provided. The skirt 
32 includes a head portion 34 for sealing with the confronting surface of 
the movable device receiving face 12, a self-seating leg 36 and arm 37 for 
sealing with the peripheral edge of the stationary probe support board 14, 
and an intermediate resilient portion 38 defining an integral resilient 
hinge that allows movement of the leg 34 in such a way as to effectively 
decouple any mechanical force transmission through the hinge 38 and into 
the self-seating leg 36 and arm 37 in sealing relation with the stationary 
probe support board. The skirt 32 has a generally F-shaped cross-section. 
In operation, with the actuation of the vacuum, the atmospheric pressure 
bears down on the head 34 and against the leg 36 of the skirt 32, bringing 
the confronting surface of the electronic circuit device receiving face 12 
and stationary probe support board 14 into sealing relation therewith. As 
the board moves into its actuated position illustrated in FIG. 4, the 
hinge 38 buckles in the direction of motion and inward toward the test 
fixture head. With the release of the vacuum and the return of the fixture 
to its unactuated condition, illustrated in FIG. 3, the hinge 38 freely 
follows the upward motion of the electronic device receivign face 12, and 
the self-seating leg 36, that is mechanically and force decoupled from the 
movement of the face 12 and head portion 34, retains its self-sealed and 
seated relation with the probe support board, all the while the vacuum is 
cyclically maintained and released. The material of the skirt 32 can be 
any suitable elastomer, such asurethane or NEOPRENE. 
It will be appreciated that many modifications including dimensional 
changes, configurations, opening dimensions of the hinge, different 
geometry hinges, different kinds of self-seating and self-sealing surfaces 
and abutting portions will become apparent to those skilled in the art 
having the benefit of this disclosure without departing from the scope and 
spirit of the claimed invention.