Electronic device securement system

A system for securing an electronic component, such as a CPU, includes a support extending substantially in a plane and a fastener coupled to the support. The support may be a heat sink secured to a component for dissipating heat generated during operation of the component. The fastener extends through extensions or fins of the heat sink, generally parallel to the plane of the heat sink and component package. A biasing spring urges the fastener toward a disengaged position. A biased retainer maintains the biasing spring and fastener within the assembly. The component is initially engaged in a receiving socket for installation. The fastener is then engaged in the mechanical support to draw the component into full engagement. A reference surface on the securement assembly contacts the mechanical support to limit engagement of the component. The fastener may include a torque-limiting assembly for limiting the torque applied to the mechanical support upon full engagement of the component.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates generally to the field of computer and 
similar electronic systems in which one or more component packages is 
installed in a socket-type connector for exchanging data with external 
circuitry. More particularly, the invention relates to a technique for 
securing a component package, such as a CPU, in a computer system to 
provide a reliable, robust and high tolerance interface between the 
component and the supporting system. 
2. Description of the Related Art 
In computer and other electronic systems, it is often necessary to assemble 
component modules at a system level to provide desired functionality. For 
example, in personal computers, servers, work stations and the like, 
central processing units, expansion cards, and other component circuits 
are often assembled with supporting circuits to define an overall system. 
Various types of supporting circuits may be envisaged for interfacing the 
components. In a typical computer system, certain of such component 
circuits are received and supported by a motherboard or system board. The 
system board serves as the base for the components, and routes both power 
and data between the component circuits and external circuitry. 
In one design for assembled computer components, a socket is provided 
directly on the supporting board to receive and to interface with the 
component circuitry. The socket includes internal connections extending 
between internal contacts and the supporting board. The component is 
inserted into the socket during assembly of the system, and has contact 
pads or pins which make electrical contact with the socket contacts. The 
socket serves both as a mechanical support for the component as well as an 
electrical interface between the supporting board and the component. 
While such conventional component support and interface schemes have proven 
generally adequate for many applications, they are not well suited to 
increasingly complex and densely packed circuit components. For example, 
due to the large number of input and output connections in certain complex 
circuit components, such as CPU's, a corresponding number of conductive 
paths must be provided in interface hardware receiving the components. To 
minimize the size of the components and the overall system, however, it is 
often desirable to confine the interface connections to a relatively small 
area. In certain known system, for example, densely packed contact pads 
are formed along an edge of a component circuit board. The circuit board 
is disposed in a protective package, and the package is intended to be 
coupled over a support socket, completing connection of the contact pads 
with respective internal conductors within the socket during installation. 
As the density and number of connections in such systems increases, 
however, so does the tolerance required for the interface components. 
Misalignment or incomplete engagement of the circuit components can render 
the systems non-functional both from the time of their initial 
installation and during subsequent use. Moreover, tolerances provided in 
conventional socket-mounting structures that facilitate insertion of 
components by hand may be simply unacceptable for more demanding 
applications wherein connections are more numerous or densely packed. 
There is a need, therefore, for an improved technique for securing circuit 
components in systems such as computer systems. There is a particular need 
for a securement system capable of providing positive engagement between a 
component and supporting interface hardware, and which offers proper 
control of alignment both during initial installation and throughout the 
subsequent life of the system. 
SUMMARY OF THE INVENTION 
The present invention provides an electronic component securement system 
designed to respond to these needs. The system may be employed with a 
variety of component circuits, but is particularly well suited for 
securement of high density circuits, such as CPU's, in computer systems. 
The system facilitates both mechanical and electrical connection the 
component on its support, affording proper alignment of the component with 
interface connections, and reference surfaces for ensuring full engagement 
while limiting movement to avoid damage to either the component or the 
support. In a favored approach, a fastener draws the component into 
engagement in a receiving socket, reducing the risk of damage that can 
result from hand installation. The fastener may be designed to be 
manipulated by hand, eliminating the need for special tooling for 
installation and removal of the component. Moreover, the system may 
provide for torque limiting, further reducing the potential for damage to 
the electrical or mechanical supports, and providing tactile feedback 
indicative of complete engagement of the component. Also, in a 
particularly favored approach, the securement system may be designed 
around a heat sink which dissipates thermal energy generated during 
operation of the component. The heat sink then serves the additional 
functions of supporting the securement system subcomponents and ensuring 
proper alignment and engagement of the electronic component in its 
interface. 
Thus, in accordance with one aspect of the invention, an assembly is 
provided for securing an electronic component to a mating support. The 
support includes a socket configured to receive a portion of the 
component. The assembly includes a base, a heat sink, and a fastener. The 
base is disposed adjacent to the socket and includes an aperture for 
receiving the fastener. The heat sink has a substantially planar 
securement surface configured to be secured to the component. The fastener 
extends through a portion of the heat sink in a direction generally 
parallel to the plane of the securement surface. The fastener is 
receivable in the aperture for securing the component in engagement with 
the socket. A biasing member may be provided between the fastener and the 
heat sink for urging the fastener towards a disengaged position away from 
the base. In a preferred configuration, a retaining member is provided for 
holding the fastener and biasing member in the assembly. The heat sink may 
include a reference surface which contacts a portion of the support upon 
full engagement of the component. 
In accordance with another aspect of the invention, an electronic component 
module is provided for assembly with a component interface. The component 
module includes an electronic component package extending substantially in 
the plane. The component package, in turn, includes an electronic 
component configured to be connected to external circuitry via a component 
interface. A securement assembly extends from the component package. The 
securement assembly includes a support and a fastener retained by the 
support. The fastener extends substantially parallel to the plane of the 
component package. The fastener is configured to be received in the 
component interface to draw the component into an installed position in 
the component interface. In one preferred arrangement, fasteners used in 
the securement technique may be adapted for limiting torque applied to the 
component support upon full engagement. The fastener may also be 
configured to be hand tightened and loosened, thereby reducing the need 
for special tooling for installation and removal of the component. 
The invention also provides a computer system including a supporting board, 
an electronic component, and a securement assembly. The supporting board 
includes an electrical socket and a mechanical support adjacent to the 
socket. The electronic component has an edge engageable in the socket for 
completing connection of the component to the supporting board. The 
securement assembly is coupled to the component and includes a heat 
dissipating member and a fastener. The fastener is coupled to the heat 
dissipating member and is engageable in the mechanical support to advance 
and retain the edge of the component in the socket. 
In accordance with another aspect of the invention, a method is provided 
for securing an electronic component to an interface. The electronic 
component extends substantially in the plane and is configured to be 
mounted substantially transverse to the interface. In accordance with the 
method, a securement assembly is coupled to the component. The securement 
assembly includes a support coupled to the component, and a fastener 
coupled to the support. The fastener extends substantially parallel to the 
plane. The component is then initially engaged with the interface to align 
the component in the interface. The fastener is engaged with the interface 
to draw the component into final engagement with the interface. The 
support may be a heat dissipating member including a plurality of fins, 
with the fastener extending through at least one of the fins. By engaging 
the fastener in the interface, the component is thus fully engaged with 
the support, providing appropriate alignment and engagement, even for 
densely packed electronic components, such as CPUs.

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS 
Turning now to the drawings, and referring first to FIG. 1, a securement 
system, designated generally by the referenced numeral 10, is illustrated 
for coupling a component 12 in a computer system 14. In the particular 
embodiment illustrated, component package 12 includes a pre-packaged 
processor assembly 16, in which a CPU is secured for mounting to a system 
board in a personal computer system or server. It should be understood, 
however, that the present technique may be applied in various types of 
systems and for various types of component packages, including CPU's, 
riser cards, expansion cards, memory devices, and so forth. 
In the embodiment shown in the Figures, processor assembly 16 includes a 
housing 18 in which a component card or circuit board 20 (see, e.g., FIG. 
4) is secured. As best illustrated in FIG. 1, housing 18 forms a generally 
box-like enclosure which protects the internal components from damage 
during shipping and installation. A securement mounting base is fixed to 
housing 18 and facilitates complete engagement and securement of the 
housing and component in the computer system. In the preferred embodiment 
illustrated in the drawings, a heat sink 22 serves this purpose. In the 
particular component package shown, heat sink 22 is secured to a face of 
housing 18 through which heat is dissipated during operation of the 
component. Where such heat dissipation is performed in other ways or is 
unnecessary in a particular application, however, an alternatively 
configured mounting support may be employed. As described more fully 
below, heat sink 22 serves both to dissipate heat from component package 
12 and to support various subcomponents of the securement system. Also, 
heat sink 22 provides a base or reference surface for ensuring complete 
engagement of the component within the computer system and for limiting 
such engagement during assembly. 
In the illustrated embodiment, computer system 14 includes a system board 
24 mounted on a support plate 26. System board 24, which may support one 
or several component packages 12, may also support additional add-on 
circuit boards, such as expansion cards, memory circuitry, and the like. 
In the illustrated embodiment, system board 24 supports various 
surface-mounted components or circuitry, represented generally at 
reference numeral 28, interconnected to perform desired functions, such as 
execution of an application software, network communications, and so 
forth. System board 24 provides interface connections for component 
package 12 via one or more surface-mounted sockets 30. Sockets 30 may be 
of any suitable design, such as conventional multi-conductor, slotted 
supports for receiving an edge of a circuit card or PC board. Parallel to 
sockets 30, mechanical supports 32 are disposed on board 24. As described 
more fully below, mechanical supports 32 provide for both positive 
securement of component package 12 to board 24, as well as referencing of 
alignment and engagement of the package upon installation. 
In a fully assembled system, system board 24 would be mounted in a chassis 
(not shown) along with various other components, such as disk drives, 
power supplies, cooling fan assemblies, and so forth. Within the chassis, 
a support frame 34 is provided for receiving component package 12 and for 
aligning the package over respective sockets 30 and mechanical supports 
32. In the embodiment illustrated in FIG. 1, support frames 34 comprises a 
metallic stamped and bent framework in which a pair of guide members 36 
are secured in mutually facing relation. Guide members 36 form slots 38 
for receiving each component package to be secured to board 24. Slots 38 
are separated from one another by partitions 40 which serve to receive a 
portion of the component package, extensions of housing 18 in the 
illustrated embodiment, and guide the package into place during 
installation. 
Several features may be provided on component package 12 for initial and 
final securement of the package in the computer system. In the illustrated 
embodiment, a pair of ejectors 42 are disposed adjacent to an upper end of 
heat sink 22. Each ejector 42 is pivotable on a rivet 44 and engages an 
inner surface of guide members 36 for initial securement of the package in 
support frame 34, as discussed in greater detail below. For final 
securement of the package in the system, and for ensuring a complete 
insertion into sockets 30, a fastener 46 extends through heat sink 22. To 
accommodate fastener 46 and associated structures described below, fins 48 
of the heat sink form recesses 50 through which the fastener passes. 
Certain of the recesses formed in fins 48 also facilitate insertion of 
additional fasteners for attaching heat sink 22 to housing 18, as 
discussed below with particular reference to FIG. 7. An upper fin 52 
serves as a support for a biasing and retaining structure for maintaining 
a fastener 46 in place and for urging the fastener to a biased position. 
Accordingly, upper fin 52 includes an aperture 54 for permitting passage 
of the fastener therethrough. Additional fins below upper fin 52 form a 
recess 56 for accommodating the retaining and biasing components, 
including a spring 58 and a retainer 60. In the illustrated embodiment, 
fastener 46 is a threaded bolt which engages and is secured within a 
corresponding threaded aperture 62 provided in mechanical support 32 on 
board 24. Alternatively, a threaded aperture 62 may include apertures 
formed within supports 32, and captive nuts provided in or below the 
apertures. 
FIG. 2 is a side elevational view of the component package following 
insertion and securement into the support frame, sockets and mechanical 
supports shown in FIG. 1. As illustrated in FIG. 2, mechanical supports 32 
are generally channel-shaped support structures, made of a heavy-gage 
metal plate. Each support 32 is secured to board 24 via fasteners 64 which 
extend through a portion thereof, and which may interface with standoffs 
66 provided between board 24 and support plate 26. Each socket 30 extends 
parallel to a mechanical support 32 and is spaced from the mechanical 
support so as to align with component 20 within the component package 
following insertion of the package in the support frame (see, e.g., FIG. 
4). Moreover, each mechanical support 32 has an upper reference surface 68 
designed to contact a corresponding lower reference surface 70 of heat 
sink 22 to limit engagement of the component package upon full insertion 
in the system. As will be appreciated by those skilled in the art, 
surfaces 68 and 70 also provide for control of parallelism and 
perpendicularity between the component housed within package 12, and 
socket 30. In the illustrated embodiment, heat sink 22 includes a rear 
panel 72 which fits flush against a face of housing 18 for transmitting 
thermal energy from the housing during operation. A series of apertures 74 
are formed in rear panel 72 to receive fasteners 76 for attaching the heat 
sink to the housing. Thus, as an assembled package, heat sink 22 serves to 
carry securement components, transfer heat from the package, and to 
provide for alignment and engagement depth control of the component upon 
securement in the system. 
FIGS. 3 and 4 show in somewhat greater detail the progressive engagement of 
package 12 in the system as described above. As illustrated in FIG. 3, 
following initial engagement of ejectors 42 (see FIGS. 1 and 2), housing 
16 is properly aligned over socket 30, but is not fully engaged therein. 
It has been found that while such ejector systems may be sufficient for 
attachment of certain devices in computer systems, they may sometimes 
permit misalignment or less than full engagement of high-tolerance 
components, particularly those including a large quantity of 
closely-spaced contact pads. Accordingly, in the embodiment illustrated in 
FIG. 3, following engagement of the ejectors provided on the component 
package, a distance designated by the letter D in FIG. 3, of approximately 
0.020 inches, remains between reference surfaces 68 and 70. Following such 
initial engagement, fastener 46 is engaged threadingly into aperture 62, 
to draw the package into full engagement on the support, as shown in FIG. 
4. Upon such full engagement, reference surfaces 68 and 70 come into 
contact with one another, limiting further engagement of component 20 in 
socket 30. As shown in FIG. 4, in the present embodiment, a slotted recess 
78 is formed in socket 30, and includes a plurality of internal electrical 
contacts 80 which contact corresponding conductive pads (not shown) on 
both front and rear sides 82 of component 20. As will be appreciated by 
those skilled in the art, electrical contacts 80 will be routed from the 
interior of socket 30 to external circuitry on system board 24 and from 
board 24, to additional circuitry included in the computer system. 
The fully-assembled component package 12 is illustrated in bottom 
perspective view in FIG. 5. As shown in FIG. 5, housing 18 forms a shell 
having a lower or bottom opening 84, providing access to an edge of 
component 20 housed therein. Thus, upon engagement of the package within 
the computer system, socket 30 is free to engage housing 18 through lower 
opening 84 to come into contact with the lower edge of component 20. Also 
as shown in FIG. 5, package 12 includes features which facilitate proper 
insertion of the package within the securement structure described above, 
particularly within support frame 34 of FIG. 1. In particular, ejectors 42 
include tabs 86 which can be grasped by a user to force pivotal movement 
of the ejectors about rivets 44. A hook-like engagement extension 88 is 
provided on each ejector for engaging a corresponding recess (not shown) 
in guide members 36 (see, e.g., FIG. 1) for initial engagement of the 
package in the securement system as described above. Moreover, to ensure 
proper alignment of package 12 in the system, recesses 90 are formed along 
one side of fins 50. As shown in FIG. 6, stops or abutment members 92 
extend from each partition 40 of at least one of the guide members 36, and 
permit sliding engagement of the package when properly aligned with 
recesses 90 of the fins. If the package is improperly aligned in the 
system, stops 92 engage a side of the fins opposite from recesses 90 to 
prevent insertion of the package in the system. 
The securement system described above may be conveniently provided as a 
subassembly of the support and attachment structures, configured for 
mounting to a component housing to form the completed component package 
12. The various subcomponents of the system facilitating this subassembly 
approach are illustrated in an exploded perspective view of FIG. 7. As 
described above, the system includes a mechanical support, such as in the 
form of heat sink 22. Fins 48 of the heat sink permit dissipation of heat 
from the component housing, and also serve as support structures for the 
securement system. In particular, heat sink 22 is designed to receive 
fastener 46, and retainer 60 which holds fastener 46 in the desired 
position within the heat sink. Biasing spring 58 urges fastener 46 toward 
a disengaged (i.e., upward) position by engagement with one of the fins, 
and is stopped in its upward position by retainer 60. A series of 
fasteners 76 extend through the heat sink and aid in forming a unitary 
package with enclosure 18. 
The preferred configurations of fastener 46 and retainer 60 facilitate both 
manufacturing, assembly, and servicing of the securement system. In 
particular, as shown in FIG. 7, fastener 46 includes a head 94 which may 
be grasped by hand for tightening of the fastener in the mechanical 
support as described above. Alternatively, head 94 may be designed to 
receive a fastening tool, such as a screw driver. Moreover, while 
conventional threaded fasteners may be provided for this purpose, in a 
particularly preferred embodiment, fastener 46 is a torque-limiting 
fastener which may be secured within the system, and provides for slippage 
once fully secured in a system, thereby preventing overtightening. 
From head 94, fastener 46 forms an elongated shank 96 terminating in a 
threaded tip 98. Spring 58 is dimensioned to fit loosely around shank 96, 
and contacts an annular abutment 100 integral with shank 96 when 
installed. Apertures 102 are provided through fans 48 which span the width 
of heat sink 22, permitting the passage of shank 96 and threaded tip 98 
therethrough. Moreover, as illustrated in FIG. 7, aperture 54 provided in 
upper fin 52 is dimensioned so as to permit passage of spring 58 and 
annular abutment 100 therethrough. 
As mentioned above, heat sink 22 includes features permitting its mounting 
on housing 18, and for securing ejectors 42 in place. In particular, a 
pair of apertures 104 are provided in upper corners of rear panel 72 for 
receiving rivets 44 used to pivotally mount ejectors 42. Moreover, as 
mentioned above, apertures 74 are provided in locations in rear panel 72 
of the heat sink for receiving fasteners 76 used to secure the heat sink 
to the component housing. In the illustrated embodiment, component housing 
18 features a metallic rear plate 106 for transmitting heat from the 
component mounted in the housing. Rear plate 106 has a series of threaded 
apertures 108 formed therein, which align with apertures 74 and 
threadingly receive fasteners 76 to secure the components of the package 
in place. 
The preferred configuration of retainer 60 also facilitates assembly of the 
component package. In the embodiment illustrated in FIG. 7, retainer 60 is 
made of a molded, resilient plastic material. A pair of biasing 
projections 110 are formed integrally with the body of retainer 60, 
extending from a rear surface thereof. Moreover, a compound aperture 112 
is formed in an upper plate 114 of the retainer for permitting passage of 
shank 96, threaded tip 98, and annular abutment 100 of fastener 46, as 
well as of spring 58 during assembly of the package. Compound aperture 112 
also serves to retain these components in the assembled package. 
Accordingly, compound aperture 112 includes a reduced dimension portion 
116 having a radius generally corresponding to that of shank 96. A greater 
dimension portion 118 is contiguous with portion 116, and is dimensioned 
to permit passage of abutment 100 and spring 58. A front panel 120 of 
retainer 60 provides a surface against which a force may be applied to 
overcome the force of biasing projections 110 for assembly of the fastener 
and biasing spring as described more fully below. 
The preferred configuration of retainer 60 is illustrated in greater detail 
in FIG. 8. As shown in FIG. 8, biasing projections 110 extend rearwardly 
from the body of the retainer. Again, upper plate 114 (shown from a bottom 
perspective view in FIG. 8) includes a compound aperture 112 having a 
region of reduced dimension 116 and a region of greater dimension 118. In 
the illustrated embodiment, biasing projections 110 are elastically 
deformable as indicated by arrows 122 in FIG. 8 to urge retainer 60 to an 
outward position in which reduced dimension portion 116 of aperture 112 
engages shank 96 above abutment 100 as described below. However, the 
biasing projections are easily deformable to facilitate assembly. 
As mentioned above, in a presently preferred embodiment, fastener 46 
includes features permitting it to limit torque applied to mechanical 
supports 32 during securement of the component package. FIGS. 9 and 10 
illustrate a presently preferred configuration for a torque-limiting 
fastener of this type. As shown in FIG. 9, fastener 46 may be configured 
as an assembly including a cap 124 forming part of the head 94 of the 
fastener. An inner housing 126 fits within cap 124 and is bounded at its 
lower extremity by an annular protrusion or ring 128. A radial bore 130 is 
formed in inner housing 126 and is dimensioned to receive a compression 
spring 132. A ball or a similar bearing component 134 also fits within 
bore 130 and is urged radially outwardly by spring 132 in operation. 
As illustrated in FIG. 10, inner surfaces cap 124 are formed to retain the 
cap on housing 126, and to limit torque of the fastener in use. 
Accordingly, an inner peripheral surface 136 of cap 124 receives housing 
126 and maintains the housing centered within the cap. An inner groove 
138, which fits below ring 128 when assembled, is designed to receive a 
snap ring or similar retaining device (not shown) for holding cap 124 in 
engagement over housing 126. Inner peripheral surface 136 also forms a cam 
surface 140 which engages ball 134 when cap 124 is placed over housing 
126. In operation, the user may turn cap 126 to rotate to fastener 46 and 
thereby threadingly engage the fastener into a threaded bore 62 of a 
mechanical support 32 as described above. However, when a maximum 
allowable torque is reached, compression spring 132 is compressed within 
bore 130, permitting ball 134 to ride over cam surface 140, causing cap 
124 to spin on housing 126. Owing to the configuration of cam surface 140, 
the fastener may be easily removed in a reverse direction by engagement of 
ball 134 with the cam surface. The ability to limit torque on the fastener 
in the securement system permits the user to have tactile and auditory 
feedback of full engagement of the component package in its socket and 
support, while providing a straightforward securement structure which does 
not require special tooling for assembly. 
FIGS. 11-13 illustrate sequential steps in assembly of fastener 46 and 
spring 58 within heat sink 22 and retainer 60. As shown first in FIG. 11, 
with retainer 60 in lace below upper fin 52 of the heat sink, fastener 46 
is passed through aperture 54 in upper fin 52, with spring 58 disposed 
about shank 96, and in contact with abutment 100. To permit passage of the 
spring and abutment therethrough, retainer 60 is depressed against rear 
panel 72 of the heat sink as indicated by arrow 142 in FIG. 11, thereby 
aligning greater dimension portion 118 of aperture 112 with aperture 54. 
FIG. 12 illustrates the same components following full insertion of 
fastener 46 and spring 58 through aperture 54 and retainer 60. At this 
stage in the assembly, spring 58 is located below upper plate 114 of the 
retainer, as is annular abutment 100. As shown in FIG. 12A, force applied 
as indicated by arrow 142 causes a deformation of biasing projections 110 
against rear panel 72 of the heat sink. The alignment of the apertures, 
including the greater dimension portion 118 of aperture 112, facilitates 
passage of the spring and abutment therethrough. 
FIG. 13 illustrates the same components following release of the retainer. 
As shown in FIG. 13, as force is removed from the front surface of 
retainer 60, as indicated by arrow 144, biasing projections 110 urge 
retainer 60 outwardly (i.e., to the right in FIG. 13, away from rear panel 
72), thereby shifting reduced dimension portion 116 of aperture 112 into 
engagement about shank 96 of the fastener. Spring 58 urges the fastener 
upwards by engagement with abutment 100. However, upward movement of the 
fastener is limited by engagement of abutment 100 against upper plate 114 
of the retainer. As illustrated in FIG. 13A, biasing projections 110 
maintain the retainer in an outward position wherein shank 96 remains 
captured within reduced dimension portion 116 of aperture 112, and 
abutment 100 remains captured below plate 114. As shown in FIG. 13B, as 
fastener 46 is then engaged to draw the component package into full 
engagement within the electrical socket and mechanical support, head 94 of 
the fastener is free to contact upper fin 52 to draw the package 
downwardly, causing a downward motion of abutment 100 and compression of 
spring 58. Retainer 60 remains urged outwardly about shank 96. 
It has been found that the foregoing biasing and retaining structure 
significantly facilitates assembly and disassembly of the component 
package. In particular, as illustrated in FIGS. 5 and 7, the securement 
portions of the component package, including heat sink 22, fastener 46, 
spring 58, retainer 60, and ejectors 42 may be premanufactured as a 
subassembly for subsequent mounting on a processor assembly 16 or similar 
package. Removal of fastener 46, such as for insertion of a fastener 76 in 
a center position of the heat sink (see, e.g., FIG. 7), is facilitated by 
simply depressing retainer 60 and partially removing fastener 46 by 
following the inverse procedure described above with respect to FIGS. 
11-13. Thereafter, the fastener can be easily reinserted in its receiving 
apertures, and the retainer released to hold the fastener and biasing 
spring securely in place. 
While the invention may be susceptible to various modifications and 
alternative forms, specific embodiments have been shown by way of example 
in the drawings and will be described in detail herein. However, it should 
be understood that the invention is not intended to be limited to the 
particular forms disclosed. Rather, the invention is to cover all 
modifications, equivalents and alternatives falling within the spirit and 
scope of the invention as defined by the following appended claims.