Component retention clip for a heat sink assembly

The present invention is directed to a mounting clip for electronic components and, more specifically, to a component retention spring clip for securing electronic components to an electronic device support such as the leg of a heat sink. In one embodiment the component retention clip is comprised of a resilient strip that has an arcuate portion and first and second ends. The resilient strip is configured to encompass an electronic component and an electronic device support adjacent to the electronic component. The arcuate portion of the component retention clip contacts a portion of the electronic component, thereby partially supporting the electronic component against the electronic device support. Located at the first end of the resilient strip is a first latch configured to cooperatively engage a corresponding second latch located at the second end and retain the electronic component on the electronic device support.

TECHNICAL FIELD OF THE INVENTION
 The present invention is directed, in general, to a mounting clip for
 electronic components and, more specifically, to a component retention
 spring clip for securing electronic components to a heat sink assembly.
 BACKGROUND OF THE INVENTION
 Electronic components often generate operating temperatures that can cause
 component damage and circuit failure if temperature control methods are
 not employed. The generally preferred temperature control method is to use
 a heat sink to transfer heat from the heat generating components to the
 ambient air surrounding the associated electronic assembly. A heat sink
 can be made of any material with favorable heat transfer characteristics,
 such as copper, aluminum or steel, although aluminum is generally
 preferred for cost and weight reasons.
 In most cases a heat generating component is placed in direct contact with
 a heat sink in order to provide for the most efficient transfer of heat
 from the component to the heat sink. After the heat sink absorbs heat from
 the component, the heat dissipates throughout the heat sink structure and
 transfers by conduction or convection to the surrounding ambient air.
 A typical electronic circuit will have a number of heat generating
 components or devices fastened to heat sinks. This usually means that the
 printed wiring or circuit board on which the heat generating components
 are mounted must be able to accommodate a number of heat sinks. This also
 means that factors other than temperature control must be taken into
 consideration when designing a board mounted electronic assembly. For
 example, the amount of real estate on the board required by heat sinks
 must be considered in designing the board layout as well as the volume of
 the space available in the enclosure housing the electronic circuit. In
 many such cases the real estate on the board and enclosure space occupied
 by heat sinks will constitute a significant percentage of the total board
 space and enclosure volume available. This means that circuit designers
 must address heat dissipation problems from a space and weight viewpoint
 in order to produce the highly valued small electronics system that
 customers prefer.
 Some of the space and volume concerns related to heat control have been
 addressed by designing new board arrangements for heat sinks. In order to
 permit such new arrangements to be used, new heat sink designs have also
 been developed to provide better thermal performance in less space.
 Designing heat sinks and arranging them to provide for more efficient
 thermal performance in a smaller space has, in some instances, created its
 own set of problems. One such problem is that the amount of working space
 on the printed circuit or wiring board has been reduced, making it more
 difficult to assemble the circuit. Another problem is that the mounting
 surfaces on the heat sink to which the heat generating components are
 fastened are not as accessible as they were on prior art heat sinks. Prior
 art threaded fastener secured clamps can sometimes be very difficult to
 use in fastening electronic components to the heat sinks. In some cases,
 the most advantageous heat sink geometry does not provide paths for tools
 to reach screws and other fasteners, thereby preventing this advantageous
 heat sink geometry from being used with prior art clamps. These prior art
 devices often require significant time and effort to attach an electrical
 component, which, of course, adds manufacturing cost and hampers
 production efficiency. Prior art spring clip designs do not address the
 problem of mounting components on the opposing sides of a heat sink leg.
 Accordingly, what is needed in the art is a device that can be used to
 secure heat generating components to a heat sink where access to the
 mounting surface on the heat sink is limited because of design
 considerations.
 SUMMARY OF THE INVENTION
 To address the above-discussed deficiencies of the prior art, the present
 invention provides a mounting clip for electronic components and, more
 specifically, to a component retention spring clip for securing electronic
 components to an electronic device support, such as the leg of a heat
 sink. In one embodiment the component retention clip is comprised of a
 resilient strip that has an arcuate portion and first and second ends. The
 resilient strip is configured to encompass an electronic component and an
 electronic device support adjacent to the electronic component. The
 arcuate portion of the component retention clip is configured to contact a
 portion of the electronic component, thereby partially supporting the
 electronic component against the electronic device support. Located at the
 first end of the resilient strip is a first latch configured to
 cooperatively engage a corresponding second latch located at the second
 end and retain the electronic component on the electronic device support.
 The present invention in one aspect, therefore, introduces a clip or
 fastener to mount an electronic component on a support, such as the leg of
 a heat sink. The invention is particularly useful for mounting an
 electronic component to a heat sink where the heat sink design provides
 only a limited amount of access space to the electronic component after it
 is placed in position for mounting. In some such cases the access space is
 so limited that it is impossible to use prior art devices to secure
 components to a heat sink. The present invention overcomes this deficiency
 found in prior art fasteners.
 In one embodiment, the resilient strip is a metallic alloy. It is
 particularly advantageous to use iron based alloys in this embodiment of
 the invention because such alloys have a superior resiliency. In another
 embodiment of the invention, the resilient strip is configured to
 encompass a plurality of electronic components. Another aspect provides
 for the resilient strip to be comprised of a plurality of arcuate
 portions. A resilient strip with a plurality of arcuate portions increases
 the total supporting structure of the clip and provide additional support
 to the component or components. This embodiment will be explained in
 detail herein.
 In still another embodiment of the invention the component retention clip
 has the first and the second latches formed from the resilient strip. One
 aspect of this embodiment provides for the first and second latches to be
 formed as hooks. This embodiment permits the clip to be secured by taking
 advantage of the resiliency of the strip to keep the hooks together after
 they have been cooperatively engaged with one another.
 The foregoing has outlined, rather broadly, preferred and alternative
 features of the present invention so that those skilled in the art may
 better understand the detailed description of the invention that follows.
 Additional features of the invention will be described hereinafter that
 form the subject of the claims of the invention. Those skilled in the art
 should appreciate that they can readily use the disclosed conception and
 specific embodiment as a basis for designing or modifying other structures
 for carrying out the same purposes of the present invention. Those skilled
 in the art should also realize that such equivalent constructions do not
 depart from the spirit and scope of the invention in its broadest form.

DETAILED DESCRIPTION
 Referring initially to FIG. 1, illustrated is an embodiment of an
 electronics assembly 100 constructed in accordance with the present
 invention that has electronic components 130 coupled to a heat sink's 110
 electronic device support legs 120 by a component retention clip 150. The
 heat sink 110 is positioned to be coupled to a printed wiring board 140.
 The heat sink 110 has a longitudinal spine 111 with cooling fins 115
 extending from each side. The heat sink 110 also has electronic device
 support legs 120 extending from the spine 111. In the illustrated
 embodiment, the support legs 120 are configured to support a plurality of
 electronic components 130 by providing a mounting surface on each side of
 each leg 120. Two of the support legs 120 are used to attach or mount the
 heat sink 110 to the printed circuit or wiring board 140.
 By mounting the heat generating components 130 directly to the heat sink
 110, component 130 heat is absorbed directly and dispersed throughout the
 heat sink's 110 structure, including its cooling fins 115. The cooling
 fins 115 then transfer the heat into the surrounding air by conduction or
 convection. When a cooling fan is used to facilitate cooling by moving air
 across the heat sink 110, the direction of air flow parallels the surface
 of the cooling fins 115 and is transverse to the spine 111 of the heat
 sink 110. The illustrated heat sink 110 embodiment is described in detail
 in U.S. Patent application Ser. No. 09/259,772, entitled TRANSVERSE
 MOUNTABLE HEAT SINK FOR USE IN AN ELECTRONIC DEVICE, Ayres, John W., et.
 al., now U.S. Pat. No. 6,201,699, commonly assigned with the invention and
 incorporated herein by this reference.
 The configuration of the heat sink's 110 electronic device support legs 120
 provides very limited space to access an electronic component 130 after it
 is positioned for mounting. This limited space makes it difficult to use
 conventional prior art spring clips, screws, bolts and other conventional
 fasteners to couple electronic components 130 to the legs 120. It is
 preferable, therefore, to use some form of clamping device to secure
 components 130 to the legs 120. As will be explained herein, the
 illustrated component retention clip 150 is particularly well suited for
 securing electronic components 130 to the illustrated heat sink's 110
 electronic device support legs 120.
 Turning now to FIGS. 2A and 2B, illustrated is an open and closed view,
 respectively, of an embodiment of a component retention clip 150
 constructed in accordance with the present invention. The clip 150 is a
 resilient strip 200 that has arcuate portions 210 and a first 220 and a
 second 230 end. In one embodiment of the invention the resilient strip 200
 is a metallic alloy. It is particularly advantageous to use iron based
 alloys because of the superior resiliency of such alloys. Located at the
 first end 220 of the resilient strip 200 is a first latch 225 configured
 to cooperatively engage a corresponding second latch 235 located at the
 second end 230. In the illustrated embodiment of the invention, the
 component retention clip 150 has first 225 and second 235 latches formed
 from the resilient strip 200. These latches 225, 235 are formed as hooks.
 FIG. 2B illustrates the beneficial aspect of this embodiment, which
 permits the clip 150 to be secured by taking advantage of the resiliency
 of the strip to keep the hooks 225, 235 fastened together after they have
 been cooperatively engaged with one another.
 It will be apparent to those skilled in the pertinent art that any type of
 latch 225, 235 located on the first 220 and second 230 ends of the strip
 200 is within the intended scope of the present invention. It is also
 apparent to those skilled in the pertinent art that the clip 150 can be
 used to attach electronic components 130 to configurations of electronic
 device supports other than the illustrated heat sink's 110 electronic
 device support legs 120.
 Turning now to FIG. 3, illustrated is a bottom view of the heat sink 110
 illustrated in FIG. 1 showing an embodiment of a component retention clip
 150, constructed in accordance with the present invention, coupling
 electronic components 130 to the heat sink's 110 electronic device support
 legs 120. This bottom view will be used to explain how the illustrated
 clip 150 works.
 The resilient strip 200 is configured to encompass the electronic
 components 130 and the electronic device support legs 120 to which the
 components 130 are coupled. An arcuate portion 210 of the strip 200
 contacts a portion of the component 130 and presses the component 130
 against the electronic device support leg 120, thereby partially
 supporting the component 130 against the support leg 120. The resilient
 strip 200 is secured about the components 130 and the support leg 120 by
 the first latch 225 cooperatively engaging the corresponding second latch
 235.
 In the illustrated embodiment the arcuate portions 210 of the strip 200
 flexes to provide elastic displacement so that the two latches 225, 235
 can be engaged by pinching the ends 220, 230 of the strip 200 together and
 releasing them. This is particularly beneficial from a manufacturing
 viewpoint because the clip 200 can be left in a relaxed state while the
 components 230 are being arranged. After the components are in place the
 clip 150 can be fastened and the components 130 will be secured against
 the support leg 120.
 In the embodiment illustrated in FIGS. 1 and 3, the resilient strip 200 is
 configured to encompass a plurality of electronic components 130. This is
 useful because it permits, in the illustrated heat sink embodiment, at
 least two electronic components 130 to be coupled to a single support leg
 120. Another particularly beneficial embodiment of the invention provides
 for a plurality of arcuate portions 210 in the resilient strip 200. This
 permits a separate arcuate portion 210 of the strip 200 to be used to
 support each separate components 130 against the electronic device support
 leg 120.
 Another beneficial aspect of the embodiment of the invention that provides
 for a plurality of arcuate portions 210 in the strip 200, is that at least
 one arcuate portion 210 can be used to support the strip 200 against an
 edge 151 of the support leg 120. This provides additional support to the
 assembly 100 and strengthens the entire structure of support leg 120,
 electronic components 130 and clip 150.
 Referring again to FIG. 3, one of the clips 151 is illustrated supporting a
 small electronic component 136 against one side of the electronic device
 support leg 120 and a larger component 135 on the other side. This
 particularly advantageous feature of the invention permits electronic
 components 135, 136 of different sizes to be supported against an
 electronic device support leg 120 by a single clip 151.
 Although the embodiments illustrated in FIGS. 1 and 3 show a strip 200 with
 a plurality of arcuate portions 210, those skilled in the pertinent art
 will understand that a single arcuate portion in the strip is within the
 intended scope of the present invention. Similarly, those skilled in the
 pertinent art will understand that a strip 200 that encompasses a single
 electronic component 130 and a support leg 120 is within the intended
 scope of the present invention.
 The invention includes several embodiments of methods of manufacturing a
 component retention clip and an electronics assembly. Sufficient detail
 has been set forth herein to enable one of ordinary skill in the pertinent
 art to understand and practice the various embodiments of such methods
 Although the present invention has been described in detail, those skilled
 in the art should understand that they can make various changes,
 substitutions and alterations herein without departing from the spirit and
 scope of the invention in its broadest form.