Patent ID: 12228202

DETAILED DESCRIPTION

The following detailed description is merely exemplary in nature and is not intended to limit the application and uses of embodiments herein. Furthermore, there is no intention to be bound by any expressed or implied theory presented in the preceding introduction and brief summary or the following detailed description. As used herein, the term “module” refers to any hardware, software, firmware, electronic control unit or component, processing logic, and/or processor device, individually or in any combination, including without limitation: application specific integrated circuit (ASIC), an electronic circuit, a processor (shared, dedicated, or group) and memory that executes one or more software or firmware programs, a combinational logic circuit, and/or other suitable components that provide the described functionality.

Embodiments of the present disclosure may be described herein in terms of functional and/or logical block components and various processing steps. It should be appreciated that such block components may be realized by any number of hardware, software, and/or firmware components configured to perform the specified functions. For example, an embodiment of the present disclosure may employ various integrated circuit components, e.g., memory elements, digital signal processing elements, logic elements, look-up tables, or the like, which may carry out a variety of functions under the control of one or more microprocessors or other control devices. In addition, those skilled in the art will appreciate that embodiments of the present disclosure may be practiced in conjunction with any number of automated driving systems including cruise control systems, automated driver assistance systems and autonomous driving systems, and that the vehicle system described herein is merely one example embodiment of the present disclosure.

Finally, for the sake of brevity, conventional techniques and components related to vehicle mechanical parts and other functional aspects of the system (and the individual operating components of the system) may not be described in detail herein. Furthermore, the connecting lines shown in the various figures contained herein are intended to represent example functional relationships and/or physical couplings between the various elements. It should be noted that many alternative or additional functional relationships or physical connections may be present in an embodiment of the invention. It should also be understood that the figures are merely illustrative and may not be drawn to scale.

Additionally, the following description refers to elements or features being “connected” or “coupled” together. As used herein, “connected” may refer to one element/feature being directly joined to (or directly communicating with) another element/feature, and not necessarily mechanically. Likewise, “coupled” may refer to one element/feature being directly or indirectly joined to (or directly or indirectly communicating with) another element/feature, and not necessarily mechanically. However, it should be understood that, although two elements may be described below, in one embodiment, as being “connected,” in alternative embodiments similar elements may be “coupled,” and vice versa. Thus, although the schematic diagrams shown herein depict example arrangements of elements, additional intervening elements, devices, features, or components may be present in an actual embodiment.

Referring to the drawings, wherein like reference numbers correspond to the same or similar components throughout the several views, there is shown inFIG.1a schematic representation of a vehicle10having an engine12and a transmission14. Embodiments will be described herein with respect to the vehicle10as an exemplary application. As such, it should be readily understood thatFIG.1is merely an exemplary application by which the present embodiments may be incorporated and practiced—i.e., the subject matter is not limited to the particular configuration ofFIG.1.

The vehicle10may be any one of a number of different types of vehicles, such as, for example, a sedan, a wagon, a truck, or a sport utility vehicle (SUV), and may be two-wheel drive (2WD), four-wheel drive (4WD), or all-wheel drive (AWD). In various embodiments, the vehicle110may incorporate any one of, or combination of, a number of different types of engines, such as, for example, gasoline or diesel fueled combustion engines, flex fuel vehicle (FFV) engines (i.e., using a mixture of gasoline and alcohol), hybrid vehicles, electric vehicle drive units (EV DUs) and transmissions.

The engine12is selectively fluidly connectable to the transmission14through a hydrokinetic power coupling device, such as torque converter16. Alternatively, the engine12is selectively mechanically connectable to the transmission14through a torque transmitting mechanism, preferably by way of a lockup clutch, shown in phantom inFIG.1as18. In other words, the lockup clutch18may be selectively engaged under certain conditions to provide a direct mechanical coupling between the engine12and transmission input shaft19, effectively bypassing the torque converter16. The transmission14includes a plurality of differential gear sets (e.g., planetary gear sets) and clutch packs, collectively depicted in phantom as17inFIG.1, to achieve the necessary transmission of power between the engine12and a rotatable output member, such as the driveshaft or transmission output shaft24.

The transmission14also includes or is in fluid communication with a single internal reservoir or sump volume, shown hidden inFIG.1at20, or multiple reservoirs (not shown). The reservoir20stores and supplies hydraulic fluid21, such as oil, which is pressurized and fed to the transmission14and/or engine12by a pump assembly22. Although depicted inFIG.1as being packaged inside the transmission housing, the reservoir20and pump assembly22may be packaged at locations outside of the transmission14.

Referring now toFIG.2, a schematic of an intake system99is provided. As shown, the intake system99includes a pump assembly22and a fluid reservoir20.FIG.2only illustrates the interconnection of components and does not illustrate the shapes of components as is contemplated herein.

As shown, the fluid reservoir20holds a hydraulic fluid50. Hydraulic fluid50has an upper surface55. InFIG.2, the vehicle is stationary and is supported by a horizontal surface, thus the upper surface55of the hydraulic fluid50lies in the horizontal plane200.

In certain embodiments, the fluid reservoir20is an oil reservoir, such as an oil pan or oil tank, and the hydraulic fluid50is oil. While the fluid reservoir20may have any suitable and desired shape, fluid reservoir20includes a reservoir bottom52or tank bottom52. Further, the reservoir20defines an internal volume25with an internal shape28including the bottom52.

As shown, the pump assembly includes a pump30, an intake40, and a pick-up tube100. The pick-up tube100has a proximal or first end101in fluid connection with the intake40. Further, the pick-up tube100has a distal or second end102located in the fluid reservoir20and in fluid connection with the hydraulic fluid50therein.

FIGS.3-6illustrate movement of the hydraulic fluid50within the reservoir20during normal vehicle operation. For example, inFIG.3, the vehicle traveling in the direction of arrow241accelerates and the hydraulic fluid50moves opposite to arrow241, relative to the reservoir20, under the influence of inertial forces indicated by arrow251. As a result, the surface55of the hydraulic fluid50is located in a plane201, i.e., an acceleration slosh plane. As shown, plane201intersects the horizontal plane200at a pitch axis210. Further, the plane201and horizontal plane200intersect at a positive pitch angle301.

InFIG.4, the vehicle traveling in the direction of arrow242decelerates and the hydraulic fluid50moves in the same direction as arrow242, relative to the reservoir20, under the influence of inertial forces indicated by arrow252. As a result, the surface55of the hydraulic fluid50is located in a plane202i.e., a deceleration slosh plane. As shown, plane202intersects the horizontal plane200at a pitch axis210. Further, the plane202and horizontal plane200intersect at a negative pitch angle302.

InFIG.5, the vehicle is traveling forward in a direction into the plane of the drawing sheet, and makes a lefthand turn in the direction of arrow243. The hydraulic fluid50moves in the opposite direction, relative to the reservoir20, under the influence of inertial forces indicated by arrow253. As a result, the surface55of the hydraulic fluid50is located in a plane203. As shown, plane203intersects the horizontal plane200at a roll axis220. Further, the plane203and horizontal plane200intersect at a positive roll angle303.

InFIG.6, the vehicle is traveling forward in a direction into the plane of the drawing sheet, and makes a righthand turn in the direction of arrow244. The hydraulic fluid50moves in the opposite direction, relative to the reservoir20, under the influence of inertial forces indicated by arrow254. As a result, the surface55of the hydraulic fluid50is located in a plane204. As shown, plane204intersects the horizontal plane200at a roll axis220. Further, the plane204and horizontal plane200intersect at a negative roll angle304.

While movement of the fluid50within the reservoir20is described inFIGS.3-6relative to inertial forces, the fluid50may also move under the forces of gravity. For example, the vehicle may be parked or driven over non-level surfaces. Likewise, the movement of the fluid50within the reservoir20may result from a combination of inertial and gravity forces. For example, inFIG.3, a vehicle traveling in the direction of arrow241that accelerates while traveling uphill would result in movement of the hydraulic fluid50, under the influence of gravity and inertial forces indicated by arrow251, to a plane201. The maximum acceleration slosh plane201results from a combination of acceleration while traveling uphill. Likewise, inFIG.4, a vehicle traveling in the direction of arrow241that decelerates while traveling downhill would result in movement of the hydraulic fluid50, under the influence of gravity and inertial forces indicated by arrow252, to a plane202. The maximum deceleration slosh plan202results from a combination of deceleration while traveling downhill.

Referring now toFIGS.7and8, a distal end102of a pick-up tube100is illustrated. As shown, the distal end102is formed with an opening500. The opening500is defined by a peripheral edge520. The peripheral edge520defines and lies substantially within an opening plane510. For example, at least 50% of the peripheral edge520lies within the opening plane510, such as at least 55%, at least 60%, at least 65%, at least 70%, at least 75% at last 80%, at least 85%, at least 90%, or at least 95%, of the peripheral edge520lies within the opening plane510. The opening plane510may be considered to have a thickness in a perpendicular direction to the plane510of less than 8 millimeters (mm), such as less than 6 mm, less than 4 mm, less than 2 mm, less than 1.5 mm, less than 1 mm, or less than 0.5 mm. Alternatively, the opening plane510may be considered to have a thickness in a perpendicular direction to the plane510of less than 25% of the maximum inner dimension of the opening500, such as less than 20%, less than 15%, less than 10% or less than 5% of the maximum inner dimension of the opening500.

The opening500is in fluid communication with an internal channel350defined by inner surfaces of walls140of the pick-up tube100. As shown, a mesh screen150is located within the internal channel350. Specifically, the mesh screen150extends across the internal channel350and contacts the inner surfaces of walls140. The mesh screen150may be mounted to the walls140.

FIG.9illustrates the position of the pick-up tube100, and specifically of the opening500, in reservoir20.FIG.9is a side cross-sectional view of the reservoir20and illustrates planes201and202. In exemplary embodiments, the opening500of the pick-up tube100is located below the plans201and202(and below planes203and204).

Further in certain embodiments, an offset is provided for each plane to ensure that the opening500remain submerged within the fluid50during vehicle operation. For example, an offset plane601is parallel to plane201and is located at a perpendicular distance610below plane201. Likewise, an offset plane602is parallel to plane202and is located at a perpendicular distance620below plane202. Similar offset planes603and604are provided at respective perpendicular distances630and640from planes203and204(as shown inFIGS.5and6).

As shown inFIG.8, the inner surfaces of walls140of the pick-up tube100form a curved short side turn259to turn flow towards the pump and delay onset of flow separation.

FIG.9also identifies a frozen water plane700. The frozen water plane700indicates the height over the reservoir bottom52at which water may freeze during periods that the vehicle is located in freezing temperature conditions while not running. To ensure proper operation of the vehicle when starting during such freezing conditions, the opening500may be located above the frozen water plane700. However, embodiments herein provide for proper operation of the vehicle even when the water plane700is higher than the bottom edge of the opening500as fluid50may enter the opening500above the water plane700.

FIG.9also illustrates that the reservoir20includes a drain58. A horizontal drain plane800is defined by the drain58. To ensure proper draining of the reservoir20, such as during an oil change, the opening500should be located above the drain plane800. However, embodiments herein provide for proper draining even when the drain plane800is higher than the bottom edge of the opening500. It is further noted that whileFIG.9illustrates drain plane800being higher than water plane700, other embodiments where water plane700is higher than drain plane800are envisioned. Further, planes700and800may be co-planar.

Thus, a volume333, having a four-sided pyramidal shape, is identified and located below offset planes601,602,603,604. In exemplary embodiments, the opening500is located within the volume333.

Further, in exemplary embodiments, the functionality of the opening500is improved by providing the opening500with an opening plane510with a positive pitch angle501of at least half of the pitch angle301. As a result, the opening500may extend from the intersection of plane601and a selected minimum distance from the tank bottom to a midpoint location on plane602. In exemplary embodiments, the opening500has an opening plane510with a positive pitch angle501equal to the pitch angle301. As a result, the opening500may extend from the intersection of plane601and the minimum distance from the reservoir bottom52to the intersection of planes601and602. In such an embodiment, the opening plane510is co-planar with plane601. Thus, embodiments herein provide for an opening500having a pitch angle501of from at least half of the pitch angle301to the pitch angle301. While the opening500is illustrated as extending the entire distance across volume333, it is contemplated that in certain embodiments, the opening500) may not extend the entire distance across volume333.

In exemplary embodiments, the pitch angle501is no more than 45 degrees, such as no more than 44 degrees, no more than 43 degrees, no more than 42 degrees, no more than 41 degrees, no more than 40 degrees, no more than 39 degrees, no more than 38 degrees, no more than 37 degrees, no more than 36 degrees, no more than 35 degrees, no more than 34 degrees, no more than 33 degrees, no more than 32 degrees, no more than 31 degrees, no more than 30 degrees, no more than 29 degrees, no more than 28 degrees, no more than 27 degrees, no more than 26 degrees, no more than 25 degrees, no more than 24 degrees, no more than 23 degrees, no more than 22 degrees, no more than 21 degrees, or no more than 20 degrees.

In exemplary embodiments, the pitch angle501is at least 15 degrees, such as at least 16 degrees, at least 17 degrees, at least 18 degrees, at least 19 degrees, at least 20 degrees, at least 21 degrees, at least 22 degrees, at least 23 degrees, at least 24 degrees, at least 25 degrees, at least 26 degrees, at least 27 degrees, at least 28 degrees, at least 29 degrees, at least 30 degrees, at least 31 degrees, at least 32 degrees, at least 33 degrees, at least 34 degrees, at least 35 degrees, at least 36 degrees, at least 37 degrees, at least 38 degrees, at least 39 degrees, or at least 40 degrees.

FIG.9also illustrates that the pick-up tube100extends from the500in the volume333to an interface35with the pump30, such that an internal fluid pathway is formed through the pick up tube100and pump30. Embodiments herein provide for maximizing the size of the opening500of the pick up tube100as a primary goal. A secondary goal is to provide a pick up tube inlet flow direction through the opening500that is aligned with the pick up tube outlet flow direction into the pump30, i.e., perpendicular to the interface35inFIG.9. In exemplary embodiments, the pick up tube inlet flow direction is less than 90 degrees from the pick up tube outlet flow direction, such as less than 80 degrees, less than 70 degrees, less than 60 degrees, less than 50 degrees, less than 45 degrees, less than 40 degrees, less than 30 degrees, less than 20 degrees, or less than 10 degrees from the pick up tube outlet flow direction.

FIGS.10-13illustrate that the opening500of the pick-up tube100remains submerged under the surface55of the hydraulic fluid50during a selected maximum acceleration, maximum deceleration, maximum lefthand turn, and maximum righthand turn, respectively.

As shown inFIGS.12-13, the bottom portion525of the peripheral edge520of opening500is substantially flat and lies within a plane parallel to the bottom52of the reservoir20.

FIGS.14and15illustrate an embodiment of a pick-up tube100. As shown, the pick-up tube100has an internal channel250with an opening500at the distal end102. As shown inFIG.14, a mesh screen150extends across the channel250. The opening500is formed at a desired pitch angle to the horizontal plane.

FIGS.16and17illustrate another embodiment of a pick-up tube100. As shown, the pick-up tube100has an internal channel250with an opening500at the distal end102. As shown inFIG.17, a mesh screen150extends across the channel250. The opening500is formed at a desired pitch angle to the horizontal plane.

FIG.18illustrates another embodiment of a pick-up tube100. InFIG.18, the oil pick-up tube is Y-shaped and includes a main tube portion261configured to extend to an oil pump, a first leg portion262configured to extend downward toward an oil tank bottom and which terminates at the distal end102and opening500, and a second leg portion263configured to extend upward away from the oil tank bottom and to a closed end264. As shown, a mesh screen150is located in the pick-up tube100and extends from the closed end264of the second leg portion263to the main tube portion261.

The mesh screen150defines a plane151that is perpendicular to a flow direction, indicated by arrow152, of fluid entering the pick-up tube100through the first leg portion262. Further, the internal channel250is formed with an angled wall255for turning the flow vector toward the pump. Also, internal channel250is formed with a curved short side turn259to turn flow towards the pump and delay onset of flow separation.

During operation in freezing temperatures, ice may build up in the mesh screen150in the region159. The embodiment ofFIG.18provides for flow fluid around the ice in region159by flowing through the second leg portion263to the main tube portion261. Thus, the screen150and second leg portion263may be sized for cold flow of the fluid.

As described inFIGS.1-18, an oil intake system99is provided with a pick-up tube100that improves function while remaining operable in all expected conditions.

The opening plane510has been described as being parallel to the plane201, and plane201has been described as an acceleration slosh plane. This arrangement is particularly useful when the pump is mounted to the rear of the pick-up tube. In certain embodiments, opening plane510is parallel to the plane201, and plane201is the acceleration slosh plane. This arrangement may be useful when the pump is mounted forward of the pick-up tube.

In exemplary embodiments, a perpendicular direction (such as arrow152) to the opening plane510is pointed at the pump intake40.

In exemplary embodiments, the opening plane510is not substantially parallel to bottom52of the reservoir20near the point of entry into the opening500.

In exemplary embodiments, the opening plane510is offset from rear and forward oil slosh planes201and202to prevent pulling air through the fluid surface55.

In exemplary embodiments, the shape of the opening500is an oval or is D-shaped. For a D-shaped opening500, the bottom portion525of the peripheral edge520is predominantly flat and parallel to the tank bottom52at the location vertically below the bottom portion525of the peripheral edge520.

In exemplary embodiments, the mesh screen is predominantly perpendicular to the main flow direction252of the fluid50entering the pick-up tube100. Such an arrangement may drastically lower fluid pressure drop through the pick-up tube100. Even for the same pressure drop, a smaller amount of air coming out of solution is a benefit when considering pump metrics. For example, there is a lower chance of self-pump regulation, less aeration into the pump rotor, and better maximum high flow capacity. Further, the screen location enables an exemplary embodiment with respect to the flow geometry immediately downstream of the pickup tube inlet plane.

In exemplary embodiments, the mesh screen150extends to the curved convex inside surface of the closed end264. This may be referred to as the suction or low pressure side of the pick-up diffuser section550, and is where flow separation may first occur. The diffuser shape is maintained along this section with no disruption by the geometry of the mesh screen150.

The diffuser section550increases in area along the flow direction. Often, the diffuser section550is conical, though other shapes may be suitable. The diffuser section550slows the fluid flow rate in a controlled manner, such that fluid flow does not separate from the wall.

In exemplary embodiments, the mesh screen150is extended above the main diffuser shape of the pickup inlet opening500.

In exemplary embodiments, the diffuser shape of pickup entry is continued downstream of mesh screen area.

In exemplary embodiments, the width around the top of mesh screen150near the closed end264is constant and the inner surfaces of the channel are predominantly parallel to the mesh screen150. The distance from the inner surfaces of the channel to the mesh screen150is provided to keep less than a selected flow rate of fluid at a cold start condition with full blockage of part of screen within main flow path, such as with ice.

Exemplary embodiments herein provide for a reduced pressure drop and better fluid flow as compared to conventional pick-up tubes.

Exemplary embodiments have an increased length of diffuser section due to the mesh screen layout. As a result, less air comes out of solution within the pick-up tube100due to lower flow separation. This is realized as maximum pump flow and for continuously variable vane pumps, results in lower slide torque. Higher slide torque is a negative for pump self-regulation.

Embodiments herein provide for better performance in conditions of high ice/water levels during cold starts. The design herein allows the water level to come up to and above the bottom of the inlet opening without starving the pump. Specifically, the remaining portion of the inlet opening extends over the ice/water level. For a typical pick-up, when the water level reaches the opening, the water will start starving the pump. A traditional pick-up requires some offset from the water/ice line. In contrast, the layout described herein, due to the more upright inlet opening plane, allows the fluid to keep flowing even when the water/ice level is above the bottom of the inlet opening.

Embodiments herein allow the reservoir to fully drain during fluid change. The upright inlet opening allows the inlet opening to overlap the bottom oil drain line, yet still allow the pump to drain. With a traditional pick-up, once the pickup inlet is under oil, the pump and galleries will not drain.

Embodiments herein allow for the drain plug nut to be located at a higher location relative to the bottom of the reservoir and still allow the reservoir and pump to fully drain.

In view of the structure described in relation toFIGS.1-18, a method is described for manufacturing an oil intake system for a vehicle. The method includes providing an oil tank having an internal volume with an internal shape including an oil tank bottom. Further, the method includes determining a selected amount of fluid, such as oil, received in the oil tank. In certain embodiments, the selected amount of fluid is a minimum amount for safe operation of the vehicle.

The method may include selecting a maximum positive pitch angle of a first plane of an upper surface of the selected amount of oil in the oil tank. For example, the maximum positive pitch angle may be the angle between the horizontal plane and the plane of the upper surface of the fluid during a deceleration or acceleration event.

The method may include selecting a minimum negative pitch angle of a second plane of the upper surface of the selected amount of oil in the oil tank. For example, the minimum negative pitch angle may be the angle between the horizontal plane and the plane of the upper surface of the fluid during an acceleration or deceleration event.

The method may further include determining a bottom plane at a selected positive distance above the oil tank bottom. For example, a minimum vertical distance for fluid flow may be determined.

The method may further include determining a shape and a size of an oil pick-up tube and of an opening in the oil pick-up tube to locate the opening below the first plane at the maximum positive pitch angle and below the second plane at the minimum negative pitch angle, wherein the opening is defined by a peripheral edge of the oil pick-up tube, wherein the peripheral edge lies substantially within an opening plane, wherein the opening plane has a positive pitch angle of at least half of the maximum positive pitch angle. Also, the method may include fabricating the oil pick-up tube with the shape, the size, and the opening.

In certain embodiments, determining the shape and the size of the oil pick-up tube and of the opening in the oil pick-up tube includes locating the peripheral edge at a first positive distance from the first plane, at a second positive distance from the second plane, and at a third positive distance from the oil tank bottom.

In certain embodiments, the method further includes selecting a maximum positive roll angle of a third plane of an upper surface of the selected amount of oil in the oil tank; and selecting a minimum negative roll angle of a fourth plane of the upper surface of the selected amount of oil in the oil tank. In such methods, determining the shape and the size of the oil pick-up tube and of the opening in the oil pick-up tube may include determining the shape and the size of the oil pick-up tube and of the opening in the oil pick-up tube to locate the opening below the first plane at the maximum positive pitch angle, below the second plane at the minimum negative pitch angle, below the third plane at the maximum positive roll angle, and below the fourth plane at the minimum negative roll angle.

In certain embodiments, the oil tank bottom defines a tank bottom plane, and determining the shape and the size of the oil pick-up tube and of the opening in the oil pick-up tube includes locating a bottom-most portion of the peripheral edge in a bottom plane parallel to the tank bottom plane.

It is noted that an opening500may be formed such that the opening plane510is co-planar with the offset plane601, such that the opening plane510is formed at an angle501equal to the pitch angle301of the slosh plane201(and offset plane601). In such an embodiment, the opening500may have a bottom at the intersection of the offset plane601and the upper plane of the planes700and800. In such an embodiment, the opening500may have a top at the intersection of the offset plane601and the offset plane602.

It is envisioned that the opening500may be formed such that the opening plane510has a pitch angle501less than the pitch angle301of the slosh plane201(and offset plane601), while the opening500remains in the volume333. For example, the top end of the opening500may be moved along the offset plane602away from the offset plane601. Thus, the angle501of the opening plane510is reduced. In certain embodiments, the angle501of the opening plane500is less than 100% of the angle301of the offset plane601, such as less than 90%, less than 80%, less than 70%, less than 60%, less than 50%, less than 45%, less than 40%, or less than 33%, of the angle301of the offset plane601. In certain embodiments, the angle501of the opening plane500is at least 30% of the angle301of the offset plane601, such as at least 33%, such as at least 40%, at least 45%, at least 50%, at least 60%, at least 70%, at least 80%, or at least 90%, of the angle301of the offset plane601.

Further, it is envisioned that the opening500may be formed such that the opening plane510has a pitch angle501greater than the pitch angle301of the slosh plane201(and offset plane601), while the opening500remains in the volume333. For example, the bottom end of the opening500may be moved along the higher plane of the planes700and800away from the offset plane601. Thus, the angle501of the opening plane510is increased. In certain embodiments, the angle501of the opening plane500is greater than 100% of the angle301of the offset plane601, such as greater than 105%, greater than 110%, or greater than 115%, of the angle301of the offset plane601. In certain embodiments, the angle501of the opening plane500is less than 120% of the angle301of the offset plane601, such as less than 115%, less than 110%, or less than 105%, of the angle301of the offset plane601.

While at least one exemplary embodiment has been presented in the foregoing summary and detailed description, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration of the disclosure in any way. Rather, the foregoing summary and detailed description will provide those skilled in the art with a convenient road map for implementing the exemplary embodiment or exemplary embodiments. It should be understood that various changes can be made in the function and arrangement of elements without departing from the scope of the disclosure as set forth in the appended claims and the legal equivalents thereof.