The invention generally relates to hand tools, and more particularly to an improved device for facilitating removal of printed circuit cards from a card rack characterized by longitudinal side rails arranged in a mutually spaced parallelism and a plurality of printed circuit cards extended between the rails of the rack

Sawyer, R. V.

Szuwalski, B.

English

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U.S. Patent No. :
Government or j J -^~~ f i^
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NASA Case No. :
NOTE - If this patent covers an invention made by a contractor
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(NASA-Case-FfiC-11042-1) CCMPUIEE CIRCUIT -"882-24839
CARD PULLEfi Patent (NASA) 5 p CSCI 09B
Unclas
00/60 13887
https://ntrs.nasa.gov/search.jsp?R=19820016963 2020-03-21T16:44:27+00:00Z
United States Patent
Sawyer et al.
[ii] 4,307,510
[45] Dec. 29, 1981
[54] COMPUTER CIRCUIT CARD PULLER
[75] Inventors: Ralph V. Sawyer; Bill Szuwalski, both
of Lancaster, Calif.
[73] Assignee: The United States Of America as
represented by the Administrator of
the National Aeronautics & Space
Administration, Washington, D.C.
[21] Appl. No.: 129,778
[22] Filed: Mar. 12,1980
[51] Int. CU H05K 3/36
[52] U.S. Cl : 29/764; 29/267;
254/131
[58] Field of Search 29/764, 758, 267;
254/129, 131, 132, 8 R; 294/15
[56] References Cited
U.S. PATENT DOCUMENTS
985,212 2/1911 Sellers 254/8 R
1,494,557 5/1924 Lumry et al 254/132
1,554,518 9/1925 Ostrander 254/132
3,178,214 4/1965 Tinkelenberg 294/15
Primary Examiner—Carl E. Hall
. Attorney, Agent, or Firm—Paul F. McCaul; John R.
Manning
[57] ABSTRACT
A device (10) adapted to seat on spaced, parallel rail
surfaces of a card rack having a plurality of printed
circuit cards (14), seated therein, each being character-
ized by a card rail (22) extended along the upper side
edge thereof. The device includes a cylindrical bar (24)
adapted to seat on the rail surfaces of the rack, a blade
(42) projected radially from the bar adapted to be re-
ceived beneath a card rail and a handle (40) affixed to
the bar in diametric opposition to the blade for facilitat-
ing manipulation of the blade for lifting the card at its
rail sufficiently for unplugging the card preparatory to
the removal thereof.
6 Claims, 3 Drawing Figures
7 '10 '
U.S. Patent Dec. 29, 1981 4,307,510
4,307,510
10
COMPUTER CIRCUIT CARD PULLER
ORIGIN OF THE INVENTION
The invention described herein was made in the per-
formance of work by employees of the United States
Government and may be manufactured and used by or
for the Government for Governmental purposes with-
out the payment of any royalties thereon or therefor.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention generally relates to hand tools, and
more particularly to an improved device for facilitating
removal of printed circuit cards from a card rack char- 15
acterized by longitudinal side rails arranged in mutually
spaced parallelism and a plurality of printed circuit
cards extended between the rails of the rack.
Currently, it is common practice to remove from
computers printed circuit cards employing a screw- 20
driver blade inserted beneath the lip of the uppermost
rail of each of the cards with the shaft of the screw-
driver being positioned to rest on the rail of an adjacent
card which functions as a fulcrum as downward pres-
sure is applied to the screwdriver handle in order to lift 25
the card, for thus releasing the card from the card rack.
Unfortunately, this technique frequently results in the
damaging of the cards, as well as electronic compo-
nents, wiring, and terminals mounted on the printed
circuit card. As a consequence, substantial amounts of 30
time often are devoted to replacing or repairing dam-
aged printed circuit cards removed from the racks of
computers.
2. Description of the Prior Art
During the course of a preliminary search conducted 35
for the invention herein described and claimed, the
following U.S. Pat. Nos. were discovered:
3,178,214: Tinkelenberg;
3,626,575: Greenspan;
3,583,744: Paine; 40
4,109,379: Rattietal.
It is believed that the patent to Tinkelenberg, U.S.
Pat. No. 3,178,214 probably constitutes the most perti-
nent prior art reference discovered during the course of
that search. This patent discloses an extractor for re- 45
moving a printed circuit card from a rack. The extrac-
tor includes a body formed of an insulating material and
includes pivot points and card engaging points. Appar-
ently, hooked ends of card engaging points are arranged
to pass through suitable apertures formed in the printed 50
circuit cards when the extractor is positioned trans-
versely across the side walls of the rack. Upon rotation
of the extractor, in a counter-clockwise direction about
its pivot points, a card is lifted a predetermined distance
sufficient for causing disengagement of the card from 55
frictional fit contact with the computer. It is believed
that it will become apparent that the patented device
differs in terms of structure from the invention herein
disclosed and that the patented device clearly does not
provide a totally satisfactory solution to the problem or 60
problems encountered in removing computer printed
circuit cards from their racks, particularly where the
cards must be frequently and repeatedly removed by
technicians and engineers on a rather routine basis.
It is, therefore, a general purpose of the instant inven- 65
tion to provide an improved device particularly suited
for use as a hand tool in removing printed circuit cards
from racks characterized by pairs of longitudinal rails
having surfaces arranged in mutually spaced parallelism
and a plurality of printed circuit cards extended in mu-
tual parallelism between the rails of the rack.
OBJECTS AND SUMMARY OF THE
INVENTION
It is an object of the instant invention to provide a
hand-operated device for use in removing printed cir-
cuit cards from a rack.
It is another object to provide a device for use in
removing printed circuit cards from computer racks
with minimal effort and substantially no attendent dam-
age.
Another object is to provide a practical and eco-
nomic device particularly adapted for use in readily and
safely removing printed circuit cards from card racks,
although not necessarily restricted thereto since the
device can be employed in removing printed circuit
cards from devices other than computers.
These and other objects and advantages are achieved
through the use of a device characterized by a cylindri-
cal bar defining a fulcrum having a rocker surface
adapted to seat on rail surfaces and a blade radially
projected therefrom, said blade being characterized by
a tip portion of a substantially curved configuration
adapted to be received beneath a rail for a printed cir-
cuit card to be removed from the rack and a handle
affixed to the bar for facilitating application of a rocking
force to said bar for lifting the card rail, as will become
more readily apparent by reference to the following
description in the claims in light of the accompanying
drawings.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a fragmented perspective view of a device
embodying the principles of the instant invention in an
operative environment.
FIG. 2 is a cross-sectional view taken generally along
lines 2—2 of FIG. 1.
FIG. 3 is a cross-sectional view taken generally along
lines 3—3 of FIG. 2.
DESCRIPTION OF THE PREFERRED
EMBODIMENT
Referring now to the drawings, with more particular-
ity, wherein like reference characters designate like or
corresponding parts throughout the several views,
there is shown in FIG. 1 a device, generally designated
10, embodying the principles of the instant invention.
As shown in the drawings, the device 10 is adapted to
be employed in removing cards from a card rack 12 of
a type frequently employed for computers. As shown,
the rack contains therein a plurality of closely spaced
printed circuit cards 14 extended between a pair of side
rails 16 and 18. These rails are extended in parallelism
along opposite sides of the rack 12, while a midrail 20 is
interposed between the side rails and extends in substan-
tial parallelism therewith.
As a practical matter, it will be appreciated that the
side rails and midrail include upper surfaces of a gener-
ally planar configuration and that the cards are electri-
cally connected in frictional fitting engagement with
suitable receptacles and plugs provided therefor
mounted in the rack, but not shown. Additionally, it is
important to appreciate that each of the cards 14 in-
cludes a card rail 22 extended across the upper edge
thereof in substantially coplanar relation with an adja-
4,307,510
cent upper surface of a side rail, but below the upper
surface of the midrail 20.
As best shown in FIG. 1, the device 10 includes a
body 24 having a substantially cylindrical surface and
includes a diametrically related bore 26, FIG. 2, located 5
midway between the opposite ends of the body 24.
Additionally, there is provided in coaxial alignment
with the cylindrical body 24 a retainer 28, the purpose
of which is to support the device against inadvertent
axial displacement. The retainer comprises a disk inte- 10
grally related to with the body 24 having a diameter
substantially larger than that of the body 24. At the end
of the body 24, opposite the retainer 28, there is a fur-
ther retainer, generally designated 30. The retainer 30,
as shown in the drawings, is secured in coaxial align- 15
ment with the body 24 employing a suitable screw 32.
The retainer 30 includes a first circular component 34
having an annular surface having a diameter slightly
larger than that of the body 24, adapted to ride on the
upper surface of the side rail 16. The diameter of the 20
circular component 34 is greater than the diameter of
the body 24 by a dimension substantially equal to the
distance between the plane of the upper surface of the
midrail 20 and the upper surface of the card rails 22.
Thus the device 10 is adapted to be positioned at a 25
uniform distance above the card rail 22 when the body
24 is seated on the upper surface of the rails 16 and 20,
FIG. 3.
Additionally, the retainer 30 includes a further circu-
lar component 36 coaxially aligned with the body 24 30
and integral with the circular component 34. The circu-
lar component 36 is of a diameter slightly greater than
that of the circular component 34 in order to provide a
surface for engaging the adjacent surface of the rail 16.
It is important to appreciate that the distance between 35
the facing surfaces of the retainer 28 and the circular
component 36 is substantially equal to the distance be-
tween the remotely related oppositely facing side sur-
faces of the rail 16 and the midrail 20. Hence, the facing
surfaces of the retainers 28 and 30 engage the oppositely 40
facing side surfaces of the rails 16 and 30 and thus pre-
clude axial displacement of the body 24 during card-
removal operations of the device 10. Thus potential for
causing damage to the cards is greatly reduced.
Extended through the diametric bore 26 of the body 45
24, there is a shaft 38 having a handle 40 affixed to one
end thereof and a blade 42 located at the opposite end of
the shaft. It is noted that for the sake of convenience,
the blade 42 is slightly curved while the distal end por-
tion thereof, designated 44, is flattened to form a thin 50
line. Thus the tip 44 of the blade 42 is configured to be
received beneath the lower surface of the card rails 22.
In practice, set screws 46 are threaded into radially
projected bores formed in the body 24 for purposes of
engaging and securing the shaft 38 within the bore 24. 55
As a practical matter, an annular groove 48 preferably is
provided for purposes of receiving the set screws 46 in
mated relation for securing the shaft within the bore.
While the operation of the device hereinbefore de-
scribed is believed to be apparent, for the sake of com- 60
pleteness, a brief summary therein is herein provided.
OPERATION
With the device 10 assembled in the manner hereinbe-
fore described, the circular surface of the component 34 65
is seated on the upper surface of a rail 16, while the
portion of the cylindrical surface of the body 24 is im-
mediately adjacent the retainer 28, is seated on the
upper surface of the midrail 20. Consequently, the pe-
ripheral surface of the circular component 34 and the
peripheral portion of the body 24 immediately adjacent
to the retainer 28 collectively functions as rocker sur-
faces for accommodating rocking motion as it is im-
parted to the body seated on the surfaces of the rails 16
and 20.
The distal end portion 44 of the blade 42 is now
seated beneath the mid portion of a card rail 22 for the
card to be removed, and downward pressure is applied
to the handle 40. Consequently, a rocking motion is
imparted to the body 24 and an upward force is applied
at the blade 42 to the lower surface of the card rail for
thus causing the card rail to be elevated. Thus the card
is uncoupled from electrical connections, and the like.
With the card 14 thus loosened within the rack 12, it is
a simple matter to extract the card manually from the
rack 12.
In view of the foregoing, it is believed to be readily
apparent that the device 10 provides a practical solution
to problems heretofore encountered in removing
printed circuit cards from the racks of computers and
the like.
What is claimed is:
1. A device for use in removing a printed circuit card
from a rack characterized by a pair of longitudinal rails
having upper surfaces arranged in mutually spaced
parallelism and a plurality of printed circuit cards hav-
ing card rails extended in mutual parallelism between
the rails of the rack, comprising:
A. a bar having a rocker surface at each of its oppo-
site ends for supporting said bar in rocking engage-
ment with said longitudinal rails, and a blade radi-
ally projected from the longitudinal axis of said bar
having a curved tip characterized by a distal end
portion flattened to form a thin line insertable be-
neath the card rail for a printed circuit card; and
B. means for lifting the printed circuit card from said
rack including a handle affixed to said bar and
projected radially therefrom for rocking said bar in
response to a force applied to said handle, whereby
said bar is seated on said longitudinal rails with said
tip inserted beneath the card rail for lifting said
card as a rocking force is applied to said bar in
response to a force applied to said handle.
2. A device as defined in claim 1 wherein said handle
is integral with said blade.
3. A device as defined in claim 1 wherein said bar is
of a length substantially equal to the span between the
outer edge surfaces of the rails and is further character-
ized by a keeper affixed to said bar at each of the oppo-
site ends thereof for restraining said bar against axial
displacement.
4. A device as defined in claim 1 wherein the keeper
located at each of the opposite ends of said bar com-
prises a disk coaxially aligned with said bar and rigidly
affixed thereto.
5. A device as defined in claim 1 wherein said rocker
surfaces are of a circular cross-sectional configuration,
the diameter of the rocker surface at one end of the bar
being greater than the diameter of the rocker surface at
the other end thereof.
6. A device for use in lifting from a computer of a
type having a card rack characterized by side rails ex-
tended in parallelism along opposite side edges thereof
and a midrail centered between the side rails and ex-
tended in parallelism therewith, printed circuit cards
arranged in side-by-side relation, each card being char-
4,307,510
acterized by a top rail extended between the side rail
and the midrail for said rack, comprising:
A. a fulcrum bar having a surface of a cylindrical
configuration of a length substantially equal to the
distance between the one side edge of the midrail to
the furthest side edge of an adjacent side rail of said
rack, and a first and second disk coaxially aligned
with and integrally related to the bar at the oppo-
site ends thereof, each disk being of a diameter
greater than the diameter of the bar, for simulta-
neously engaging a side edge surface of the midrail
and one side rail for restraining said fulcrum bar
against axial displacement relative to the rails,
means including a segment of said cylindrical sur-
face adjacently related to the first disk surface
defining a first rocker surface for said fulcrum bar
at one end thereof, and a second rocker surface for
said fulcrum bar at the opposite end thereof, com-
10
15
20
25
30
35
40
45
50
55
60
prising a segment of an annular surface defined on
the second disk in coaxial relation therewith; and
;
. a blade projected diametrically through said bar
for lifting a printed circuit card, said blade having
a relatively thin arcuate lip portion flattened to
form a thin line at the distal end thereof and being
insertable beneath the top rail of the printed circuit
card, when said first and second rocker surfaces are
seated on the upper surfaces of the midrail and a
side rail, respectively, for said rack, said blade hav-
ing a handle integral therewith and projected radi-
ally from said bar, opposite said blade, for facilitat-
ing manipulation of the device for imparting an
upwardly directed force to the top rail of the
printed circuit card for thereby lifting said card
relative to said rack.
65


Computer circuit card puller

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