Patent Description:
Greenhouses are buildings or complexes in which plants are grown. For various reasons including price, it is typically ideal for greenhouses to operate with as much natural sunlight as possible. To supplement natural light from the sun, high powered lights are used within greenhouses when the sun or other natural light does not provide enough light for optimal plant growth.

However, the operation of the high powered lights is more costly than utilizing free sunlight. More so, conventional high powered lights are larger in size, which blocks the incoming free sunlight. Furthermore, the blocking of the incoming sunlight causes shading on the plants within the greenhouse, which negatively impacts the grower's productivity.

Although light emitting diodes (LEDs) are more efficient than traditional high powered lights, their manufacturing costs are higher. Additionally, the LEDs cause excessive shading based on requiring larger fixtures to dissipate heat. To circumvent the large fixtures required to dissipate the heat, some manufacturers have attempted to build smaller LED fixtures that use active cooling fans. However, in greenhouse environments, active cooling fans quickly clog with dirt, bugs, etc. This causes the LED fixtures with active cooling fans to quickly become inoperable.

Conventional LED fixtures that do not include active cooling fans use traditional linear heat sinks. However, traditional linear heat sinks include wings that extend in a direction parallel with a central axis of the conventional LED fixtures. Heat generated through conventional LED fixtures may dissipate based on convection, conduction or radiation. However, due to LED fixtures being suspended, there is minimal heat dissipation via conduction. Radiation is a function of the fixture temperature and may be significant, and convection is the primary method to dissipate heat. In applications, air particles remove heat from the fixture through air movement. For longer heat sinks, air movement within the middle of the fixtures is minimal. This severely limits the amount of power conventional LED fixtures can consume because additional power consumption leads to more heat.

Accordingly, needs exist for more effective and efficient systems and methods for heat sinks with exposed fins allowing for additional air flow.

The present invention is set out by the appended independent claims and dependent claims.

Non-limiting and non-exhaustive embodiments of the present invention are described with reference to the following figures, wherein like reference numerals refer to like parts throughout the various views unless otherwise specified.

Embodiments utilize a series of exposed fins that increase the surface area of the heat sink creating additional air flow. The fins are exposed on both sides of a central axis of the heat sink and an upper surface of the heat sink. This allows cooler air to be drawn internally towards the central axis of the heatsink, above the heat source, and flow upward and out of the heat sink. This process may cool the fins by passively moving cooler air into the body of the heat sink. Additionally, the spacing between the fins may be wide enough to allow for air to freely enter the heatsink via the sides of the fins and/or through exposed lower surfaces of the fins.

<FIG> depicts a cross flow heat sink <NUM>, according to an embodiment. Cross flow heat sink <NUM> may be configured to dissipate heat from a heat source, such as a light fixture, wherein the light fixture may be positioned under heat sink <NUM>. In a conventional linear heat sink, the heat generated from the heat source flows around a solid heat sink. In cross flow heat sink <NUM>, the generated heat may be configured to flow through fins <NUM>, and into spaces between fins <NUM>. This may more rapidly and efficiently dissipate the generated heat. Heat sink <NUM> may include fins <NUM> and rails <NUM>.

Fins <NUM> are extrusions from a unitary block of metal, such as aluminum. The extrusions consist of fins extending from an upper surface <NUM> of the unitary block of metal towards or to base <NUM>, wherein the extrusions are formed by inserting the unitary block of metal through a die that include fin portions. Remaining portions of the unitary block of metal may form fins <NUM> via the negative of the die. The extrusions to fins <NUM> extend from a first edge <NUM> to a second edge <NUM> of heat sink <NUM>. As such, the extrusions form fins that extend across the central axis of heat sink <NUM>. In embodiments, the extrusions may create fins extending from first edge <NUM> to second edge <NUM>. The extrusions may cause a plurality of evenly spaced fins <NUM> from a first end <NUM> to a second end <NUM> of heat sink <NUM>. For example, each extrusion may cause fins <NUM> to be <NUM>/<NUM>th of inch spaced from each other. However, in other embodiments fins <NUM> may have different even spacing, such as <NUM>/<NUM>rd spacing, <NUM>/<NUM>th inch spacing, etc..

Fins <NUM> have planar edges <NUM>, <NUM>, <NUM>. Accordingly, sides of fins <NUM> extend in a direction perpendicular to the central axis of heat sink <NUM>, and the upper surface <NUM> of fins <NUM> extend in a direction that is perpendicular to planar edges <NUM>, <NUM>.

Base <NUM> is formed simultaneously with the fins <NUM> by inserting the unitary block of metal through the die.

Rails <NUM> are coupled to base <NUM> via coupling mechanisms, such as screws <NUM>, fasteners, etc. In embodiments, rails <NUM> may be bonded to base <NUM> via welding, adhesives, coupling mechanism, and/or any other type of fastening scheme. Rails <NUM> extend from first end <NUM> to second end of heat sink <NUM>. Rails <NUM> may be configured to add rigidity and support for fins <NUM>. Rails <NUM> may include planar external sidewalls, and tapered internal sidewalls <NUM>. The internal sidewalls <NUM> may extend outward from a position below base <NUM> to the planar external sidewalls.

<FIG> depicts a cross flow heat sink <NUM>, according to an embodiment. Elements depicted in <FIG> may be described above. For the sake of brevity, an additional description of these elements is omitted.

As depicted in <FIG>, base <NUM> forms a lower surface of fins <NUM>, wherein base <NUM> is simultaneously with fins <NUM> by inserting the unitary block of metal into the die. Therefore, a secondary operation is not be necessary to create a continuously planar base <NUM>.

Furthermore, rails <NUM> may be affixed to base <NUM> via screws <NUM>.

<FIG> illustrates a method <NUM> for manufacturing a heat sink, according to an embodiment. The operations of method <NUM> presented below are intended to be illustrative. In some embodiments, method <NUM> may be accomplished with one or more additional operations not described, and/or without one or more of the operations discussed.

At operation <NUM>, a block of metal is inserted into a die. The may be utilized to cut or shape the block of metal to form fins and a base. The negative of the die may form a cross flow heat sink.

At operation <NUM>, a base and fins are simultaneously formed by operation <NUM>, wherein the block of metal is extruded to create a plurality of fins and the base. The extrusions may extend from an upper surface of the block of metal towards a lower surface of the block of metal, which is formed by the base. Additionally, the extrusions may occur across the width of the heat sink, which may create at least three exposed edges and a hollow chamber between adjacent.

At operation <NUM>, rails are coupled to the base via coupling mechanisms. The rails may have a first ends coupled to the outer sidewalls of the base, and second ends positioned underneath the base, wherein the second ends may not be directly coupled to the base. The rails may be utilized to couple multiple sections of extruded metal together to form a continuous heat sink.

<FIG> illustrates a method <NUM> for utilizing a heat sink, according to an embodiment. The operations of method <NUM> presented below are intended to be illustrative. In some embodiments, method <NUM> may be accomplished with one or more additional operations not described, and/or without one or more of the operations discussed. Additionally, the order in which the operations of method <NUM> are illustrated in <FIG> and described below is not intended to be limiting.

At operation <NUM>, air below a heat sink may be heated by a light fixture positioned directly below the heat sink.

At operation <NUM>, the heated air may travel upward and around rails of the heat sink.

At operation <NUM>, the heated air may travel into the body of the heat sink towards a central axis of the heat sink via extrusions on both sides of the heat sink between fins.

At operation <NUM>, the heated air may conduct upward from a position proximate to the central axis of the heat sink above the light source, and away from the heat sink via extrusions between fins on the upper surface of the heat sink. Accordingly, as hot air rises, cooler air may be drawn into the heatsink. This process may cool the fins.

<FIG> depicts an unassembled cross flow heat sink <NUM>, according to an embodiment. As depicted in <FIG>, cross flow heat sink <NUM> may be comprised of various sections <NUM> of fins, wherein sections <NUM> are coupled together along a longitudinal axis of heat sink <NUM> via rails <NUM>. As such, the length of the heat sink may be based on the number of sections <NUM> of heat sink <NUM> that are positioned adjacent to each other.

As depicted in FIGURE <NUM> it is desired to increase the heat flow from the heat source through the fins. By increasing the surface area of the heat sink <NUM> via the fins, as hotter air <NUM> rises cooler air is draw into the heatsink <NUM>. The cooler air may cool the fins.

As depicted by air flow lines <NUM> in FIGURE <NUM>, heat generated by a heat source below the heat sink <NUM> may travel around an overhang and towards a central axis of the heat sink <NUM>. The hotter air positioned proximate to the central axis may rise due to cooler air entering the hat sink via the fins. Due to the fins created by the extrusions, the hotter air may be able to travel laterally and vertically through the heat sink.

Furthermore, the heat sink may include a rib <NUM>. Rib <NUM> may extend across the central axis of the heat sink. However, rib <NUM> may not extend across the entire height of the fins. Rib <NUM> may be formed by not extruding across the entire height of a unitary block of metal along the central axis of heat sink <NUM>. Rib <NUM> may be formed by the un-extruded block of metal, wherein two fins are formed on both sides of rib <NUM> by fully extruding the entire height of unitary block of metal on both sides of rib <NUM>.

Additionally, the upper surface <NUM> of the fins may be extruded to form contours, depressions, grooves, ridges, projections, etc. By having a non-planar upper surface <NUM>, turbulences may be created. The turbulences may cause more efficient air flow through the fins and heat sink.

<FIG> illustrates a method <NUM> for a heat sink with a rib, according to an embodiment. The operations of method <NUM> presented below are intended to be illustrative. In some embodiments, method <NUM> may be accomplished with one or more additional operations not described, and/or without one or more of the operations discussed. Additionally, the order in which the operations of method <NUM> are illustrated in <FIG> and described below is not intended to be limiting.

At operation <NUM>, air below the heat sink may be heated by a light fixture positioned directly below the heat sink.

At operation <NUM>, the heated air may travel around angled protrusions on the base of the heat sink, wherein the ends of the angled protrusions is positioned between the rib and the ends of the fins.

At operation <NUM>, the heated air may enter the heat sink via partially exposed lower surfaces of the fins, wherein the lower surface of the fins are partially exposed from the first end of the protrusions to outer edges of the fins.

Claim 1:
A method for manufacturing a heat sink having a central axis, comprising:
forming a plurality of fins extending across the central axis of the heat sink from a first end (<NUM>) of the heat sink to a second end (<NUM>) of the heat sink by extruding a unitary block of metal;
simultaneously forming a base with the plurality of fins positioned below the plurality of fins;
coupling rails to the base extending from the first end (<NUM>) of the heat sink to a second end (<NUM>) of the heat sink.
wherein the fins have planar edges;
wherein sides of the fins extend in a direction perpendicular to the central axis of the heat sink.