Removable blower for convection oven

An convection oven with a removable blower wheel system is provided. The oven includes motor with a corresponding motor shaft, a first hub engageable with the motor shaft, a blower wheel, and a second hub. Each of the first hub, blower wheel, and second hub include corresponding radial apertures formed in consistent positions on each component. A plurality of shafts extend through each of the first and second hubs and the blower wheel to cause the three components to rotate together.

TECHNICAL FIELD

The present disclosure relates to the field of ovens to heat food products. Specifically, the present disclosure relates to blower wheels for convection ovens.

BACKGROUND

Certain types of convection ovens may provide a flow of heated air to surround a food product to be cooked in addition to providing radiant heating to cook the food product. A blower wheel within the internal housing of the oven that is rotatable during operation of the oven may be used to urge the forced convection air flow.

Blower wheels that are provided in convection ovens are normally rotated by torque produced in an output shaft of a motor. When mounting the blower wheel to the output shaft, structure is required to prevent the motor shaft from rotating with respect to the blower wheel. One technique is to provide a spline on the motor shaft with a corresponding recess in the internal central hole of the blower wheel to prevent this relative rotation. Apertures are typically provided in each of the motor shaft and the blower wheel to receive one or more set screws.

Convection ovens are often used the commercial food service industry. Many geographic regions have laws and/or regulations that require commercial food service entities to maintain some baseline level of cleanliness within the equipment that is used to prepare and cook food that is sold to consumers. These regulations often include the requirement to pass periodic and surprise on-site inspections from government officials. Accordingly, there is a need for the establishments in the commercial food service industry to maintain a program to ensure that their equipment used to prepare and cook food is adequately clean and sanitary, to comply with government regulations and customer understanding that cleanliness and sanitation is an important aspect of their operations.

Blower wheels must often be removed from the motor shaft to repair or replace the blower wheel or other associated components of the convection oven or to provide space for cleaning the internal volume of the oven. It is difficult and time consuming to remove conventional blower wheels from a motor shaft, often requiring a relatively complex procedure and specialized tools for removal, alignment, and replacement of the blower wheel. Accordingly, it is desired to provide removable blower wheel for a convection oven that is relatively easy to remove, replace, and align, such that the commercial food service personnel can successfully and efficiently perform these tasks.

BRIEF SUMMARY

In order to address the deficiencies of prior convection ovens discussed above, an oven and method of use are described below.

A removable blower wheel assembly is provided that includes a first hub including a disc portion and a protruded portion, wherein a central aperture is defined through the disc and protruded portions. The disc portion is configured to receive a plurality of shafts that extend in parallel to the protruded portion. A blower wheel defines a central hole and a plurality of first apertures defined around the central hole, wherein the protruded portion of the first hub extends through the central hole. A second hub includes a disc portion and a protruded portion, wherein the protruded portion of the first hub extends within and through the protruded portion of the second hub, and a plurality of second apertures are defined in the second hub. A plurality of shafts extend through the respective plurality of first and second apertures.

A convection oven is provided that includes a housing defining an internal cooking region and a motor with an output shaft that rotates during motor operation. A first hub includes a disc portion and a protruded portion and a central aperture is defined through disc and protruded portions. The disc portion is configured to receive a plurality of shafts aligned in parallel to the protruded portion. A blower wheel is provided with a central hole and a plurality of first apertures disposed radially outward from the central hole, wherein the protruded portion of the first hub extends through the central hole. A second hub includes a disc portion and a protruded portion, wherein the protruded portion of the first hub extends within a portion of the protruded portion of the second hub, wherein the second hub defines a plurality of second apertures, wherein the plurality of shafts extend through the respective plurality of first and second apertures when a portion of the output shaft extends through the first and second hubs and the blower wheel.

A removable blower wheel assembly is provided that includes a first hub including a disc portion and a protruded portion, wherein a central aperture extends through the disc portion and the protruded portion. A blower wheel defines a central hole to accept the protruded portion of the first hub. A second hub is provided that includes a disc portion and a protruded portion, wherein the protruded portion of the first hub extends within the protruded portion of the second hub. A means to removeably connect each of the first hub, the blower wheel, and the second hub is additionally provided.

Advantages of the disclosed oven and methods of use will become more apparent to those skilled in the art from the following description of embodiments that have been shown and described by way of illustration. As will be realized, other and different embodiments are contemplated, and the disclosed details are capable of modification in various respects. Accordingly, the drawings and description are to be regarded as illustrative in nature and not as restrictive.

DETAILED DESCRIPTION

Turning now toFIGS. 1-9and specifically toFIG. 9, a removable blower wheel system10for use with a convection oven11is provided. The removable blower wheel system10includes a motor20with output shaft22, a first inner hub40, a blower wheel60, and a second outer hub80. The removable blower wheel system10is normally included within an oven housing12that forms an internal cooking volume13. The motor20and output shaft22are positioned within the housing12such that as the blower wheel60rotates due to the torque provided by the motor20through an associated motor shaft22, causing forced air flow through the convection oven11. The air within the convection oven11is normally heated by radiant heaters (not shown). The heated air flowing past a food product within the cooking volume13causes heat to transfer from the air to the food product due to convection heat transfer.

The motor20and its associated shaft22are normally positioned such that the motor shaft22extends into the inner housing12of the oven. The distal output end24of the motor shaft22includes a recessed portion26, which may include female threads or other connection structures known in the art. The output shaft22additionally may include a key28, spline, or similar structure adapted to mate with an opposing keyway or spline to cause the torque within the motor shaft22to be transferred to the opposing structure. In other embodiments, the distal end24of the motor shaft may include flat surfaces formed within the round shaft that mate with corresponding flats in the opposing structure to transfer torque. In still other embodiments, the motor shaft22may be formed or provided with other structures known to those of ordinary skill in the art.

As best shown inFIGS. 2-3, a first, or inner hub40is removeably connected to the distal end24of the motor shaft22. Specifically, the first hub40includes a hollow central portion52that is sized to fit around the distal end24of the motor shaft22. The hollow central portion52may include a keyway54, a spline, or another similar structure to engage the corresponding structure for transferring torque on the motor shaft22. In other embodiments, both the first hub40and the motor shaft20may include tapped holes (not shown) each adapted to receive a set screw (not shown) to engage the motor shaft22and the first hub40together. The structure to engage each of the distal end24of the motor shaft22and the first hub40is preferably formed such that the end surface of the distal end24of the motor shaft22extends along the same plane as the end surface50of the protruded portion48of the first hub40.

The first hub40includes a disc portion42and a protruded portion48. The hollow central portion52extends through the centers of both of the disc and protruded portions42,48. The first hub40includes a plurality of apertures44that are formed on the disc portion42. The apertures44may be aligned along a circle that surrounds and is coaxial with the protruded portion48. Each of the apertures44are preferably formed at the same radius from the centerline41of the hub40. Additionally, the apertures44are each also preferably formed at consistent arc lengths from adjacent apertures44around the circumference of the first hub40. For example, in some embodiments, the first hub40includes four apertures44that are each separated from the adjacent radial apertures by an arc length of substantially ninety degrees. In other embodiments, the first hub40includes three apertures44that are each separated from adjacent apertures44by an arc length of substantially one hundred and twenty degrees. In other embodiments, the first hub40may include other numbers of apertures44separated at corresponding arc lengths.

As shown inFIG. 4, the blower wheel60is formed with a center plate63and a fan plate65and includes a plurality of vanes66disposed between the center and fan plates63,65. The vanes66are normally formed such that the blower wheel60is operable to direct air through the convection oven with the motor shaft22being rotated in either direction. Accordingly, the vanes66are normally formed as straight vanes66. In other embodiments, the vanes66may be formed with a different shape to create more efficient air flow in a specific rotational direction of the motor shaft22.

The center plate63includes a central aperture64that is formed with a slightly larger diameter than the outer diameter of the protruded portion48of the first hub40. When the blower wheel60is connected with the first hub40, the rear surface63bof the center plate63contacts the forward surface42aof the disc portion42of the first hub40.

The blower wheel60additionally includes a plurality of apertures64that are formed around the central aperture62. Preferably, blower wheel60includes the same number of apertures64as the number of apertures44provided in the first hub40. Additionally, the apertures64are preferably provided at the same radius from a centerline61of the blower wheel60and at the same arc length between adjacent apertures64as the apertures44of the first hub40. Accordingly, when the blower wheel60and the first hub40are mated and properly aligned, the centerlines44aof the apertures44of the first hub40and the centerlines64aof the plurality of apertures64of the blower60are co-linear.

Turning now toFIGS. 5-6, second hub80is provided that includes a disc portion82and a protruded portion88. Each of the disc and protruded portions82,84of the second hub80are hollow with a circular cross-section. As best shown inFIG. 7, the inner diameter of the majority of the hollow portion of the second hub80is slight larger than the outer diameter of the protruded portion of the first hub40. The protruded portion88of the second hub80includes a front end89that includes a central aperture89athat is substantially larger than the inner diameter of the recessed portion26on the distal end24of the motor shaft22. As best shown inFIG. 8, when each of the motor shaft20, first hub40, blower wheel60, and second hub80are assembled, the distal end24of the motor shaft22contacts the inner surface89bof the front end of the protruded portion88of the second hub80.

The second hub80includes a plurality of apertures84disposed on the disc section82. Preferably, the apertures84are positioned at the same relative positions with respect to the centerline81of the second hub80as the apertures44of the first hub40are positioned with respect to the centerline41of the first hub40. Accordingly, when the first hub40, blower wheel60, and second hub80are each aligned, the centerlines44a,64a,84aof each respective aperture44,64,84are collinear.

A plurality of shafts90are provided that extend through each of the apertures44,64,84to maintain each of the first hub40, blower wheel60, and second hub80in alignment when these components are assembled, such that the motor shaft22torque is transferred to the blower wheel60. In some embodiments as shown inFIGS. 1 and 8, the plurality of shafts90may each be rigidly, or permanently, mounted to the apertures44in the first hub40. For example, the apertures44in the first hub40may be tapped with internal female threads (not shown) that can engage with similar male threads (not shown) on an end portion of the shafts90. Alternatively, the plurality of shafts90may be positioned within the apertures44in the first hub40and spot welded or brazed into position. Accordingly, as the blower wheel60and the second hub80are mated to the first hub40, the plurality of shafts90extend through the respective radial holes64,84on the blower wheel60and the second hub80, respectively, to prevent relative rotation between the three components.

In other embodiments as shown inFIGS. 10-11b, the plurality of shafts90may be mounted (either rigidly, or permanently, or with a releasable connection as discussed above) with the respective plurality of apertures84in the second hub80. The plurality of shafts90should be disposed therein to extend through each of the respective plurality of apertures64in the wheel60and the plurality of apertures44in the first hub40. In other embodiments, the plurality of shafts90may be mounted to the plurality of apertures64in the wheel60. The plurality of shafts90should be disposed within the respective apertures64such that a portion of each shaft90extends on opposite sides63a,63bof the center plate63to allow for receipt in each of the plurality of apertures84in the second hub80and the plurality of apertures44in the first hub40.

Turning now toFIGS. 1 and 7, a fastener100is provided and includes a male inserting end102and a head104. The male end102is formed with a slightly smaller outer geometry than the inner geometry of the recessed portion26of the motor shaft22. In some embodiments, the recessed portion26of the motor shaft22may be formed with internal female threads and the male end102may be formed with corresponding male threads. In other embodiments, the recessed portion26may include an internal key that is engageable with a corresponding keyway on the male end102of the fastener100, or the two components may be formed with one or more flats that prevent relative rotation between the two. The head104of the fastener100is formed with a larger diameter than the recessed portion26of the motor shaft22as well as the central aperture89in the protruded portion88of the second hub80.

When the fastener100engages the motor shaft22, the head104presses against the second hub80, which maintains all of the components of the removable blower wheel10in alignment. The head104may be formed with the arms105similar to the wings that extend from a wing nut to allow the user to grasp and manipulate the fastener100without any external tools. Alternatively, the head104may be formed to receive a typical Phillips or slotted screwdriver, or may be formed to receive an Allen wrench or another type of driver. In other embodiments, the head104may be formed to allow the user to easily remove and reinstall the fastener100onto the motor shaft.

In some embodiments, a spring washer108, such as a Belleville washer, may be provided between the head104of the fastener100and the front end89of the protruded portion88of the second hub80. This spring washer108provides compressive force, which compresses the blower wheel60between the first hub40and the second hub80. Due to the incorporation of this spring washer108, the components of the removable blower wheel10may be assembled for use, with minimal torque placed on the fastener100. Specifically, through experimental testing, it has been found that the blower wheel60is adequately retained by the first and second hubs40,80for use at the normal rotational speed of the motor20, which is between approximately 500 and 2500 RPM, depending on the type of convection oven11and the cooking setting used, when the fastener100is only retained to the motor shaft22at a “finger tight” torque level, or a torque level of between approximately 6 to approximately 10 foot pounds.