Backplane removal and insertion tool

A tool for removal and insertion of a backplane or other electrical member with respect to a housing comprises a frame which can be fixed with respect to the housing and a carriage which can be connected to the electrical member. The carriage is guided in floating relation with respect to the frame and is movable in a first direction to remove the electrical member and in a second direction to insert the electrical member. Fixing the frame with respect to the housing prevents movement of the frame away from the housing, thereby enabling application of force to the carriage sufficient to overcome resistance to insertion of the electrical member.

FIELD OF THE INVENTION 
The invention relates to a tool which is operable to generate a force in 
either of two opposite directions to both separate and connect mating 
electrical components, in particular to both remove and insert a backplane 
with respect to a card cage. 
BACKGROUND OF THE INVENTION 
Electronic components generally have electrical terminals which join with 
mating terminals of associated components. Mating pairs of terminals may 
be of the type wherein one terminal is frictionally engaged in the other 
terminal. Each mating pair of frictionally engaging terminals exhibits a 
resistance to connection or disconnection, and a force must be applied to 
overcome the resistance. For electronic components having numerous 
terminals, the sum of the forces for all of the mating pairs may be quite 
large, thereby necessitating that a relatively large force be applied to 
connect or disconnect the components. In some cases it is quite difficult 
to apply such force due to the components being somewhat fragile and being 
packaged closely together, thereby making hand access difficult. 
Various tools are known for separating electronic components which are in 
mating engagement. See, for example, U.S. Pat. Nos. 2,409,289 to Levin et 
al., 2,513,821 to Schneider, and 3,516,142 to DeRose et al. Each of these 
patents discloses a pulling tool comprising a pair of cooperating frame 
members one of which rests on a base or socket for an electronic 
component, and the other of which engages the electronic component to be 
removed therefrom. A camming member is operable to draw the one frame 
member toward the other, thereby disengaging the electronic component from 
its respective base or socket. However, none of these tools is operable to 
exert a force for reinserting the electronic component to its base or 
socket. 
U.S. Pat. No. 3,059,206 to Williams discloses a tool which is specially 
adapted for connecting and disconnecting mating plug and receptacle 
connectors. The tool has a pivotable handle and cam arrangement connected 
to move a pair of clamp members relatively together or apart upon pivoting 
of the handle. Each clamp member is attached to a respective plug or 
receptacle on opposite sides of a connector junction. The plug and 
receptacle are connected by moving the clamp members relatively together, 
and are disconnected by moving the clamp members relatively apart. In this 
regard, the tool of Williams operates contrary to the other tools 
discussed above wherein the frames are moved relatively together to 
disconnect mating components. The tool of Williams spans a connector 
junction and is not operable from one side of a connector junction to both 
join and disjoin mating connectors, as is necessary to both remove and 
insert a backplane from outside of a card cage type enclosure, for 
example. 
There is a need for a simple tool which enables both connection and 
disconnection of mating electrical components. There is also a need for a 
tool which is operable to both couple and decouple mating electrical 
components from one side of an electrical connector junction. Such a tool 
would be particularly useful for coupling and decoupling a backplane from 
multiple mating connectors in a card cage enclosure. In order to remove a 
backplane from a card cage heretofore, it has been necessary to 
electrically disable the entire system and remove from the card cage all 
daughter boards which were connected to the backplane. There is a need for 
a tool which enables removal of a backplane while associated daughter 
boards remain in the card cage. The present invention provides a tool 
having these and other advantages. 
SUMMARY OF THE INVENTION 
A tool for coupling and decoupling a backplane or other electrical member 
with at least one mating member fixed with respect to a housing comprises 
a frame, means for securing the frame to the housing, a carriage, means 
for securing the carriage to the electrical member, means for guiding the 
carriage in floating relation with respect to the frame, and means for 
moving the carriage along the means for guiding in a first direction to 
remove the electrical member and in a second direction to insert the 
electrical member. The means for securing the frame prevents movement of 
the frame away from the housing, thereby enabling application of force by 
the means for moving sufficient to overcome resistance to coupling of the 
electrical member with the mating member. 
In one embodiment, the frame comprises a substantially U-shaped member 
having an open end defined by a pair of feet mountable on the housing, and 
the carriage comprises a substantially U-shaped member disposed interiorly 
of the frame. The means for moving comprises a cam actuator assembly 
coupled between the frame and the carriage. The cam actuator assembly 
includes a pivotable cam member which defines an eccentric cam slot, and a 
cam follower is disposed in the slot. Sides of the slot define inner and 
outer cam surfaces which act to move the cam follower in one direction or 
the other during pivoting of the cam member.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
A tool according to the invention as shown in FIGS. 1 and 2 is specially 
adapted to remove and insert a backplane 2 with respect to a card cage or 
other housing 8. The card cage 8 provides an enclosure for electronic 
components and associated daughter boards, and the backplane 2 carries 
circuit paths which enable electrical interconnection of the daughter 
boards. The backplane 2 spans an opening 5 of the card cage 8 through 
which the backplane 2 makes electrical connection with the daughter boards 
in the card cage. The electrical connection or junction of the backplane 2 
with the daughter boards defines an imaginary plane extending parallel to 
the backplane 2. An important aspect of the present invention is that the 
tool mounts on one side of the plane and is operable to exert a force in 
either of two opposite directions transverse to the plane. 
In FIG. 2 a representative daughter board 4 is shown connected to the 
backplane 2 by a representative connector 6 which may be, for example, a 
card edge connector, a pin and socket connector or other wiping connector. 
Typically, a number of other daughter boards extending parallel to the 
daughter card 4 are similarly connected to the backplane 2. The connector 
6 includes a backplane header 6a which is attached to the backplane 2, and 
a daughter board receptacle 6b which is attached to the daughter board 4. 
The backplane header 6a has numerous terminals which receive contacts of 
the daughter board receptacle 6b therein. Each of the terminals exerts a 
frictional force on its respective contact, the sum of the frictional 
forces being sufficiently large to maintain the backplane 2 in connection 
with the daughter board 4. In order to remove or insert the backplane 2 
with respect to the card cage 8, the total frictional force must be 
exceeded by application of an outside force which is sufficient to couple 
or decouple the backplane 2 with or from its associated daughter boards. 
The card cage 8 and the backplane 2 are specially adapted for use with the 
tool of the present invention. In one embodiment as shown in FIGS. 1 and 
2, holes 16 are provided in the card cage 8 at the time of manufacture at 
locations selected to avoid interference with components in the card cage 
when the tool of the present invention is being used. Angle members 42 
having apertures 34 are attached to the backplane 2 to provide a structure 
which can be more easily gripped by the removal and insertion tool. 
Optional guide posts 32 which extend from the card cage 8 are receivable 
in complementary holes in the backplane 2 and angle members 42 and serve 
to correctly align the backplane over the opening 5 of the card cage. 
A tool according to the invention comprises a frame 10 and a carriage 20 
each preferably having a generally U-shape with the carriage 20 being 
disposed interiorly of the frame 10. The tool includes a means for 
securing the frame 10 to the card cage 8, and a means for securing the 
carriage 20 to the backplane 2 or other electrical member. 
In the embodiment shown in the FIGS. 1 and 2, legs of the U-shaped frame 10 
are bent outwardly to define feet 12 mountable on the card cage 8. Holes 
14 in the feet 12 are alignable with the holes 16 defined by the card cage 
8. A means for securing the frame 10 to the card cage 8 comprises 
fasteners 18 which are engageable in the holes 16 such as by mating 
threaded engagement. The fasteners 18 are preferably held loosely captive 
in the holes 14 so as to retain the fasteners 18 to the frame 10 when the 
tool is unattached to the card cage 8, although the fasteners 18 may be 
threadedly engaged in the holes 14 for the same purpose. Alternate means 
for securing the frame 10 to the card cage 8 could be quarter-turn 
fasteners or cooperating slots and tabs. 
A means for securing the carriage 20 to the backplane 2 comprises 
oppositely oriented plungers 24 which are engageable in the apertures 34. 
The plungers 24 reside in holes 26 defined by legs of the U-shaped 
carriage 20. The plungers 24 are captively held and biased by springs 28 
such that the plungers 24 are urged exteriorly of the U-shaped carriage 
20. The springs 28 are shown in FIG. 2 but are omitted from FIG. 1 for 
clarity. Finger grips 22 enable the plungers 24 to be retracted from their 
normal position against the bias of the springs 28 so that the legs of the 
carriage 20 can be inserted between the angle members 42, as shown in FIG. 
2, whereupon the plungers 24 are releasable for engagement in the 
apertures 34, as shown in FIG. 3. 
Guide beams 46 provide a means for guiding the carriage 20 in floating 
relation with respect to the frame 10. The guide beams 46 may be fixedly 
attached to, for example, the frame 10, and the carriage 20 may have 
complementary holes which receive the pins 46 with a slip fit so that the 
carriage 20 is slidable thereon. Alternatively, the guide beams 46 may be 
fixedly attached to the carriage 20 and be slidable in holes defined by 
the frame 10, or the frame and carriage may both be slidable on pins which 
are prevented from being withdrawn from the frame and carriage such as by 
spring clips. 
The tool includes a means for moving the carriage along the means for 
guiding in a first direction to remove the backplane 2 with respect to the 
card cage 8, and in a second direction to insert the backplane with 
respect to the card cage. The means for moving may include a cam actuator 
assembly shown generally as 50 coupled between the frame 10 and the 
carriage 20. The cam actuator 50 includes a cam member 52 which is 
pivotable on pin 54 attached to the frame 10. The cam member 52 has an 
eccentric cam slot 56 defined by inner and outer cam surfaces 57, 58, 
respectively. A cam follower 60 which extends from the carriage 20 rides 
in the cam slot 56. The cam member 52 includes an elongated lever arm 68 
which enables a tool operator to pivot the cam member 52 on the the pin 
54. When the cam member 52 is pivoted, the cam follower 60 is urged by a 
respective one of the cam surfaces 57, 58 in one direction or the other to 
move the carriage 20 relatively toward or away from the frame 10. 
Application of the tool to remove a backplane from a card cage will now be 
discussed. With reference to FIG. 3, with the plungers 24 retracted 
against the bias of the springs 28, the legs of the carriage 20 can be 
introduced between the angle members 42. The plungers 24 are then released 
to engage in their respective holes 26, and the fasteners 18 are engaged 
in the holes 16 to secure the tool to the card cage 8. The tool can now be 
used to remove the backplane 2. A tool operator urges the lever arm 68 
downwardly to pivot the cam member 52 clockwise on the cam pin 54. FIG. 4 
depicts an intermediate stage of tool operation. As the cam member 52 is 
pivoted in the direction of arrow A, the eccentric outer cam surface 58 
draws the cam follower 60 toward the cam pin 54, thereby drawing the 
carriage 20 toward the fixed frame 10 and drawing the backplane 2 away 
from the card cage 8 in the direction of arrow B. FIG. 5 depicts complete 
withdrawal of the backplane 2 beyond ends of the guide posts 32 and 
complete separation of the backplane header 6a from the daughter board 
receptacle 6b. The fasteners 18 can then be disengaged from the card cage 
to permit complete removal of the backplane therefrom. 
A replacement backplane 2 can be inserted on the card cage 8 by reversing 
the removal process. With a replacement backplane held on the tool by the 
plungers 24, the fasteners 18 are reengaged with the card cage 8. The 
lever arm 68 is lifted upwardly to pivot the cam member 52 
counter-clockwise, whereby the inner cam surface 57 urges the cam follower 
60 toward the card cage. As the backplane header 6a engages the daughter 
board receptacle 6b, resistance to insertion of the circuit board in the 
connector produces a reaction force at the cam pin 54 which tends to pull 
the frame 10 away from the card cage. The reaction force is resisted by 
the means for securing the frame to the housing such as the fasteners 18 
which are engaged in the card cage, thereby enabling application of force 
by the cam actuator 50 sufficient to overcome resistance to insertion of 
the backplane with respect to the card cage. 
FIG. 6 shows an embodiment of the tool wherein pairs of like tool elements 
are joined in side-by-side spaced apart relationship, for example, to 
operate on a backplane of extended length. In particular, the frame 
comprises a pair of substantially U-shaped frame members 10, 10A having 
respective open ends defined by respective pairs of feet 12, 12A mountable 
on the card cage 8. The U-shaped frame members 10, 10A are spaced apart 
and connected by at least one strut and preferably a pair of struts 17. 
Similarly, the carriage comprises a pair of substantially U-shaped 
carriage members 20, 20A disposed interiorly of the frame members 10, 10A. 
A means for moving the carriage comprises a pair of cam actuator 
assemblies 50, 50A each coupled between respective ones of the frame 
members 10, 10A and the carriage members 20, 20A. The cam actuators 50, 
50A are joined by a bar 70 which extends between respective lever arms 68, 
68A of the cam assemblies to enable simultaneous operation thereof. 
An alternate embodiment of a tool according to the invention is shown in 
FIGS. 7-9 wherein elements like those of the previously discussed 
embodiments are referred to by the same reference numbers. As shown in the 
drawings, a cover 74 attached to the backplane 2 is formed from sheet 
material. Margins of the sheet are formed to provide channels 76 the 
bottoms of which seat on the backplane 2 and are attached thereto by any 
suitable means. Slices in a wall of each channel 76 enable sections along 
the walls to be formed into a plurality of tunnels 78 which may receive 
suitable hook members therein. The card cage 8 is provided with a 
plurality of apertures 82 which similarly may receive suitable hook 
members therethrough. 
A means for securing the frame 10 to the card cage 8 comprises hooks 84 
which are receivable through the apertures 82. A means for securing the 
carriage 20 to the backplane comprises hooks 86 which are receivable in 
the tunnels 78. When the hooks 84 are inserted through the apertures 82, 
the entire tool is slidable leftwardly for a short distance along the card 
cage 8. The hooks 84 will then coextend behind a wall of the card cage 8 
adjacent to each of the apertures 82, the wall of the card cage thus 
defining a catch for each of the hooks 84 and preventing withdrawal of the 
tool away from the card cage. Simultaneous with sliding of the tool along 
the card cage, the hooks 86 of the carrier 20 are moved into the tunnels 
78 which thereby provide a respective catch for each of the hooks 86 and 
secure the holder 20 to the backplane 2. 
A means for guiding the carriage 20 in floating relation with respect to 
the frame 10 comprises the holder having a pair of brackets defining slots 
98 which receive an extension tab 96 extending from the frame. 
The holder 20 carries cam followers 60 each of which is supported near its 
ends by two brackets 64 and 66. Heads 92 of the cam followers 60 are 
received in slots 94 which serve as a secondary means for guiding the 
carriage 20 with respect to the frame 10. 
Handles 90 are provided on the frame 20 to allow an operator to more easily 
grip and maneuver the tool. 
A novel feature of the embodiment shown in FIGS. 7-9 is that the hooks 86 
are somewhat longer than the hooks 84. When the tool is secured to the 
card cage 8, the hooks 84 coextend along wall portions of the card cage 8 
adjacent to the apertures 82, and the hooks 86 coextend along walls of the 
tunnels 78. After the backplane 2 has been decoupled from its daughter 
boards by operation of the cam actuators 50 to draw the backplane 2 away 
from the card cage 8, the tool is movable through a first distance 
relative to the card cage 8 (to the right as shown in the drawings) 
whereby the hooks 84 become aligned with the apertures 82. During this 
maneuver, the hooks 86 are partially withdrawn from the tunnels 78, but 
end portions of the hooks 86 still remain within the tunnels. At this 
time, the tool having the backplane 2 secured thereto may be withdrawn 
from the card cage 8. The tool is then movable through a second further 
distance with respect to the card cage whereby the hooks 86 are withdrawn 
completely from the tunnels 78 and the backplane 2 is released from the 
tool. 
The invention has the advantages of providing a simple tool which is 
operable to both remove and replace an electrical member with respect to a 
socket or seat for the electrical member, and in particular to both remove 
and insert a backplane With respect to a card cage. The tool mounts on one 
side of a plane defined by an electrical connector junction and is 
operable to exert a force in either of two opposite directions transverse 
to the plane. The tool enables a backplane to be decoupled from its 
daughter boards and removed from a card cage without removing any of the 
daughter boards from the card cage. The tool is also useful for removing a 
midplane from a card cage after the daughter boards on one side of the 
midplane have been removed. 
The invention having been disclosed, a number of variations will now become 
apparent to those skilled in the art. Whereas the invention is intended to 
encompass the foregoing preferred embodiments as well as a reasonable 
range of equivalents, reference should be made to appended claims rather 
than the foregoing discussion of examples, in order to assess the scope of 
the invention in which exclusive rights are claimed.