Compact Loading Device

Abstract

The present invention relates to a system and apparatus for applying force in a compact form factor. The force application device includes a worm gear, a worm wheel gear engaged with the worm gear, a gear shaft coaxial with the worm gear and rotatably coupled to the worm wheel gear, a first threaded bore near a first end of the gear shaft, a second threaded bore near a second end of the gear shaft opposite the first end, a first threaded shaft received by the first threaded bore, and a second threaded shaft received by the second threaded bore, the first threaded shaft and the second threaded shaft configured to move toward or away from each other in response to rotation of the worm gear.

Description

[Technical field]

[0001] The present invention relates to systems and devices for applying forces in a compact form factor, and in particular to systems and devices for a compact gearbox configured to be positioned between two objects to attract the two objects together or to push the two objects apart.

[0002] [Citation to Related Applications] This application claims priority to U.S. Patent Application No. 17 / 649,427, filed January 31, 2022, which is incorporated by reference in its entirety. [Background technology]

[0003] Force application tools are useful in a variety of fields. Applications that utilize force application tools include, for example, jacks to lift vehicles for changing tires, automatic door opening devices, and other applications where motion is imparted by mechanical devices. Hydrodynamically driven devices are often used in applications where a pump transfers hydraulic fluid from one chamber to another to drive a piston, for example. The transfer of hydraulic fluid can be accomplished by mechanical means, for example, in the case of a bottle jack, or by electrical means, for example, an electric pump used to drive a hydraulic cylinder used in lifting a dump truck bed. Electrical force application tools may employ a motor that rotates a shaft to drive a gear to impart motion, for example, by a rack and pinion. The form factors of different force application tools vary depending on the application, with larger tools typically capable of applying larger forces over longer distances. Summary of the Invention

[0004] The present invention relates to systems and devices for applying forces in a compact form factor, and in particular to systems and devices for a compact gearbox configured to be positioned between two objects to attract the two objects together or to push the two objects apart. Embodiments provided herein include a force application device comprising a worm gear, a worm wheel gear engaged with the worm gear, a gear shaft coaxial with the worm wheel gear and rotatably coupled to the worm wheel gear, a first threaded bore disposed near a first end of the gear shaft, a second threaded bore disposed near a second end of the gear shaft opposite the first end, a first threaded shaft received by the first threaded bore, and a second threaded shaft received by the second threaded bore, the first threaded shaft and the second threaded shaft configured to move toward or away from each other in response to rotation of the worm gear causing the worm wheel gear and thus the gear shaft to rotate relative to the first threaded shaft and the second threaded shaft.

[0005] According to an exemplary embodiment, the second threaded shaft has a void, and in response to the first threaded shaft and the second threaded shaft moving toward each other, the first threaded shaft is received within the void of the second threaded shaft. In response to the first threaded shaft and the second threaded shaft moving toward or away from each other, in an exemplary embodiment, the first threaded shaft exerts a first force on a first object coupled to the first threaded shaft and the second threaded shaft exerts a second force on a second object coupled to the second threaded shaft, the first force and the second force being equal and opposite in magnitude. The first threaded shaft and the second threaded shaft are coaxial in some embodiments. The first threaded shaft and the second threaded shaft are held in a rotationally fixed state in some embodiments.

[0006] According to an exemplary embodiment, the worm wheel gear is a first worm wheel gear, the gear shaft is a first gear shaft, and the apparatus has a second worm wheel gear engaged with the worm gear, a second gear shaft coaxial with the second worm wheel gear and rotatably coupled to the second worm wheel gear, a third threaded hole provided near a first end of the second gear shaft, a fourth threaded hole provided near a second end of the second gear shaft, a third threaded shaft received by the third threaded hole, and a fourth threaded shaft received by the fourth threaded hole, the third threaded shaft and the fourth threaded shaft configured to move toward or away from each other upon rotation of the worm gear causing the second worm wheel gear and thus the second gear shaft to rotate relative to the third threaded shaft and the fourth threaded shaft.

[0007] According to exemplary embodiments, the apparatus further includes a gearbox housing the worm gear, the first worm wheel gear, the first gear shaft, the second worm wheel gear, and the second gear shaft, the first threaded shaft and the fourth threaded shaft being disposed on a first side of the gearbox and the second threaded shaft and the third threaded shaft being disposed on a second side of the gearbox. According to some embodiments, the first threaded shaft, the second threaded shaft, the third threaded shaft, and the fourth threaded shaft each move in unison toward or away from the gearbox at the same speed in response to rotation of the worm gear. According to some embodiments, a first object is attached to the first threaded shaft and the fourth threaded shaft, a second object is attached to the second threaded shaft and the third threaded shaft, the first threaded shaft and the second threaded shaft apply a first force between the first object and the second object in response to a first rotation of the worm gear, and the third threaded shaft and the fourth threaded shaft apply a second force between the first object and the second object in response to a second rotation of the worm gear, the first force being different from the second force. According to some embodiments, the first threaded hole has a first thread pitch and a first diameter, and the second threaded hole has a second thread pitch and a second diameter, the first thread pitch being the same as the second thread pitch and the first diameter being different from the second diameter. According to some embodiments, the second threaded shaft is provided with a cavity, the cavity having a diameter larger than the first diameter. The first threaded shaft and the second threaded shaft, according to some embodiments, are coaxial and extend along a first axis, the first axis being perpendicular to the rotation axis of the worm gear.

[0008] Embodiments provided herein relate to a force application system comprising a gear shaft, the gear shaft having a first threaded hole near a first end and a second threaded hole near a second end, the force application system further comprising a first threaded shaft received in the first threaded hole, the first threaded shaft having a first diameter, the force application system further comprising a second threaded shaft received in the second threaded hole, the first threaded shaft having a void, the void having a void diameter greater than the first diameter, the first threaded shaft and the second threaded shaft approach each other in response to rotation of the gear shaft relative to the first threaded shaft and the second threaded shaft in a first direction, the first threaded shaft being received within the void as the first threaded shaft and the second threaded shaft continue to approach each other.

[0009] According to some embodiments, the system further includes a worm wheel gear attached to the gear shaft and a worm gear engaged with the worm wheel gear, the worm gear configured to rotate the worm wheel gear in response to rotation of the worm gear. The first threaded shaft and the second threaded shaft are, according to some embodiments, coaxial and extend along a first axis, the first axis being perpendicular to the axis of rotation of the worm gear. Rotation of the worm gear in a first direction, according to some embodiments, causes the first threaded shaft to move toward the second threaded shaft. Rotation of the worm gear in a second direction, according to some embodiments, causes the first threaded shaft and the second threaded shaft to move away from each other.

[0010] According to some embodiments, the system further includes a first object attached to the first threaded shaft and a second object attached to the second threaded shaft, and rotation of the worm gear in a first direction pulls the first object toward the second object, and rotation of the worm gear in a second direction pushes the first object away from the second object. According to some embodiments, the force exerted by the first threaded shaft on the first object is equal in magnitude and opposite in direction to the force exerted by the second threaded shaft on the second object. According to some embodiments, the first threaded shaft and the second threaded shaft, in some embodiments, have the same thread pitch. According to some embodiments, a maximum stroke distance is defined as the longest distance the first threaded shaft moves relative to the second threaded shaft, and the maximum stroke distance is greater than the length of the gear shaft along the axis of the gear shaft.

[0011] Having thus described the invention in general terms, reference will now be made to the accompanying drawings, which are not necessarily drawn to scale. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1 illustrates an exemplary embodiment of a prior art semi-continuous casting mold. [Diagram 2] FIG. 1 shows an ingot formed by a prior art semi-continuous casting process. [Diagram 3] FIG. 2 is a top view of a semi-continuous casting mold with bendable sides to a non-curved state in accordance with an exemplary embodiment of the present invention. [Figure 4] FIG. 2 is a top view of a semi-continuous casting mold with sides bendable into a curved configuration in accordance with an exemplary embodiment of the present invention. [Diagram 5] FIG. 1 is a plan view of a pair of semi-continuous casting die assemblies positioned to enable a semi-continuous casting operation, with a compact force device positioned between the die assemblies, in accordance with an exemplary embodiment of the present invention. [Figure 6] FIG. 1 is a plan view of a pair of semi-continuous casting die assemblies positioned to enable a semi-continuous casting operation in accordance with an exemplary embodiment of the present invention, with a compact force device positioned between the die assemblies to impart curvature to the die sidewall assemblies. [Figure 7] FIG. 1 illustrates a compact force application device according to an exemplary embodiment of the present invention. [Figure 8] FIG. 2 is a cutaway view of the internal components of a compact force device according to an exemplary embodiment of the present invention. [Figure 9] 1 is a cross-sectional view of the internal components of a compact force device according to an exemplary embodiment of the present invention; [Figure 10] 1 is a cross-sectional view showing internal components of a compact force device in an extended position in accordance with an exemplary embodiment of the present invention. [Figure 11] 2 is a cross-sectional view showing the internal components of a compact force apparatus in a retracted position in accordance with an exemplary embodiment of the present invention. FIG. [Figure 12] 8 illustrates the compact force device shown in FIG. 7 in a retracted position, in accordance with an exemplary embodiment of the present invention. [Figure 13] FIG. 1 illustrates a system including several compact force devices actuated by two different drive shafts according to an exemplary embodiment of the present invention. [Figure 14] 1 is a schematic diagram of a controller for controlling one or more compact force devices according to an example embodiment of the present invention. [Figure 15] 1 is a flow diagram of a process for using a compact force device in accordance with an exemplary embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Exemplary embodiments of the present invention will now be described in more detail below with reference to the accompanying drawings, in which some, but not all, embodiments of the present invention are set forth. Indeed, the present invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein, but rather, these embodiments are provided so that this disclosure will satisfy applicable statutory requirements. Like reference characters refer to like elements throughout.

[0014] Embodiments of the present invention generally relate to mechanisms for pulling or pushing two objects toward or away from one another. While such mechanisms exist in a variety of form factors, using a variety of means for exerting force, the embodiments described herein include a compact device for applying force between two objects. Embodiments of the present invention employ a gearbox configured to minimize the space taken up by the force application device located between the two objects.

[0015] The embodiments described herein are suitable for use in a variety of applications, as will be appreciated by those skilled in the art. While there are a variety of applications for the embodiments of the present invention, exemplary embodiments are described in the context of direct chill casting, where the compact force tooling described herein may be utilized between adjacent objects. For clarity of understanding, exemplary embodiments are described below.

[0016] Vertical direct chill casting is a process used to make ingots that may have large cross sections that can be used in a variety of manufacturing applications. The vertical semi-continuous casting process begins with a horizontal table having one or more vertically oriented mold cavities. Each of the mold cavities is initially closed at its bottom with a starter block or starter plug to seal the bottom of the mold cavity. Molten metal is introduced into each mold cavity from a metal distribution system to fill the mold cavity. As the molten metal near the bottom of the mold adjacent to the starter block solidifies, the starter block is moved vertically downward along a linear path. The starter block may be moved by hydraulically lowering a platform on which it is mounted. The vertical downward movement of the starter block draws solidified metal out of the mold cavity while additional molten metal is introduced into the mold cavity. Once initiated, the process proceeds at a relatively steady state, with the semi-continuous casting process forming a metal ingot having a contour shape defined by the mold cavity and a height determined by the travel depth of the platform and starter block.

[0017] During the semi-continuous casting process, the mold itself is cooled to promote solidification of the metal as the starter block advances downwardly prior to the metal exiting the mold cavity, and a cooling fluid is introduced to the surface of the metal located near the exit of the mold cavity as the metal is being cast, thereby drawing heat from the cast metal ingot and solidifying the molten metal within the now solidified skin of the ingot. As the starter block is advanced downwardly, a cooling fluid may be sprayed directly onto the ingot, thereby cooling the surface and drawing heat from within the ingot's core.

[0018] Semi-continuous casting allows ingots to be cast in a variety of sizes and shapes with a variety of profiles. Rectangular ingots are the most common, but other profile shapes are possible. Circular billets benefit from a uniform shape, where the distance from the outer surface to the core around the billet is even all the way around. Rectangular ingots, however, lack this uniformity of surface-core depth and thus present additional challenges that must be considered during the semi-continuous casting process.

[0019] Semi-continuous casting dies for making ingots with rectangular contours do not have perfectly rectangular die cavities due to deformation of the ingot as it cools after it leaves the die cavity. The portion of the ingot leaving the die cavity as the platform and starter block are lowered retains a molten or at least partially molten core within the skin. As the core cools and solidifies, the outer contour of the ingot changes, and as a result, the die cavity contour does not have the same shape or contour as the final cooled ingot, although this defines the shape of the final cooled ingot.

[0020] FIG. 1 illustrates an exemplary embodiment of a conventional semi-continuous casting mold 100 that is received within a table or frame assembly of a semi-continuous casting system. As illustrated, the mold 100 has first and second opposing side walls 110, 120 that extend between a first end wall 130 and a second end wall 140 of the mold cavity. The first and second opposing side walls 110, 120 and the first and second end walls 130, 140 combine to form a mold cavity 150 having a generally rectangular contour shape. The first and second opposing side walls 110, 120 are arcuate in shape or have at least some curvature relative to the wall contour shape. This shape allows the cast ingot to have substantially flat opposing sides during the steady state casting operation of the semi-continuous casting process. The end walls 130, 140 can also have a specified shape, such as a curvature, a series of flat sides arranged in an arc, a compound curvature, or straight sides. The "steady state" portion of the casting process described herein is that portion of the casting process after the initial start-up or start-up casting stage and before the end or final casting stage of the casting process. Steady state casting occurs when the temperature distribution of the portion of the ingot exiting the mold cavity remains constant or nearly constant. Different casting control parameters may be desired from the start-up to the steady state to the end stages based on the type of material being cast.

[0021] Although semi-continuous casting molds have been designed and developed to produce ingots having substantially flat sides with a rectangular profile for the ingot portion produced during the steady state portion of the casting process, the start-up process of the semi-continuous casting method presents a challenge in distinguishing the start-up casting stage process and the initial portion of the ingot formed during the start-up casting stage process from the steady state stage of the casting process and the portion of the ingot formed during the steady state casting.

[0022] During the start-up phase of semi-continuous casting, high thermal gradients induce thermal stresses that cause the ingot to deform in a manner distinct from that which occurs during the steady-state phase of casting. Due to the changes in thermal gradients and stresses that occur between the start-up and steady-state phases of casting, a constant contour shape of the die cavity results in a non-uniform contour shape of the ingot portion cast during the start-up phase, also referred to as a butt, and the ingot cast during the steady-state casting phase. Since the portion produced during steady-state casting forms the majority of the ingot, the die contour shape may be designed such that the sides and opposite ends of the ingot are substantially flat. This may result in a butt of the ingot that lacks the substantially flat sides formed during the start-up phase, as shown in the cast ingot cross-section of FIG. 2. The illustrated embodiment of FIG. 2 shows a basic cross-section of an ingot die during the casting process. As shown, molten metal is received in the mold cavity between the mold side walls 110, 120, where it transitions to solid metal near the sump indicated by dashed line 163. The start block 157 in the illustrated position has already been lowered with the platform 159 in the direction of arrow 162, and casting is now in a steady state phase, with the sides 165 of the ingot 160 being substantially flat. A portion of the ingot 160 produced during the start-up phase is shown adjacent the start-up block 157 with a bulging profile 170 relative to the desired flat sides 175 of the steady state casting phase.

[0023] The deformation 170 of the ingot portion created during the start-up phase may not be usable depending on the end use of the ingot, and therefore the portion of the ingot formed during the start-up period may be sacrificed (i.e., cut off from the ingot and repurposed / recast). This sacrificial butt portion of the ingot may be quite large in size, especially in semi-continuous casting dies with relatively large contour shapes, and the butt may be recast, so that no material is lost, but the high temperature rate of the semi-continuous casting process is reduced as a result of the lost portion of the ingot and the loss of time, reheat / remelt costs and labor associated with the reduced maximum size availability of one ingot. Similar problems may occur at the end of the casting when forming the "head" of the ingot or billet, where the casting is no longer at steady state and may require specific control parameters to maximize the usable portion of the ingot and reduce waste.

[0024] To solve or ameliorate the above problems, a semi-continuous casting die may employ flexible opposing sidewalls that can be dynamically moved during the casting process to eliminate butt swelling and reduce waste in conventional semi-continuous ingot casting dies and increase ingot casting efficiency. The semi-continuous casting die described herein may have a pair of opposing casting surfaces on the flexible die sidewalls that allow the sidewalls to change shape while the die is casting the ingot. Each of the opposing sidewalls may include two or more contact portions or force-receiving elements, each configured to receive a force that dynamically moves the opposing sidewalls of the die to change shape during the casting process. The forces applied to the two or more contact areas may be independent and may include forces in opposite directions, as further described below. The contact areas may optionally be repositionable along the length of the opposing sidewalls to allow greater control over the shape of the sidewalls due to the applied forces.

[0025] FIG. 3 is a plan view of a semi-continuous casting mold assembly 200 according to an exemplary embodiment of the present invention. As shown, the mold assembly 200 includes first and second opposing sidewall assemblies 210, 220 and first and second end wall assemblies 230, 240. Each of the opposing sidewall assemblies 210, 220 includes a sidewall of the mold assembly 250, which cooperates with the end walls of the end wall assemblies 230, 240 to define a mold cavity profile that is the shape of the perimeter of the mold cavity. FIG. 4 is a plan view of the semi-continuous casting mold assembly 200 of FIG. 3, in which a curvature is imparted to the sidewall assemblies 210, 220.

[0026] Various mechanisms may be used to impart curvature to the sidewall assembly of the semi-continuous casting mold. In practice, however, semi-continuous casting molds are often arranged in a set of semi-continuous casting molds positioned adjacent to one another above the casting pit. The size of the casting pit and the frame above the casting pit that supports the semi-continuous casting molds limits the number of semi-continuous casting molds that can be used during a single casting run. By positioning the semi-continuous casting molds as close together as practicable, the capacity of the casting pit and the system is increased, thereby increasing the overall efficiency of the casting operation.

[0027] FIG. 5 shows how two semi-continuous casting mold assemblies 200 are positioned adjacent to each other when positioned in the mold frame 200 above the casting pit. The mold assemblies 200 can be supported by the mold frame in various ways, and the mold assembly supports have been omitted from the drawing for ease of understanding. As shown, the mold side walls 210, 220 are spaced apart from each other. In the absence of side wall motion, the mold assemblies can abut each other. However, to allow for side wall bending for the purposes described above, the mold assemblies must be spaced apart to some extent. Furthermore, they must accommodate a mechanism configured to cause side wall bending. A compact force device 300 is shown between the mold side walls 210, 220. In the case where a mold side wall is not adjacent to another mold side wall, but is instead adjacent to the mold frame 205, a compact force device 305 substantially similar to the compact force device 300, but adapted to be positioned between the mold side wall and the frame, at least temporarily, can be employed. These force devices, in their compact configuration, allow the die assemblies to be positioned relatively close together. Large force devices require a significant amount of space between the die assemblies, which increases the separation distance and reduces the capacity and therefore efficiency of the casting operation. The embodiments described herein provide a compact force device that can be positioned between the die side walls while requiring substantially less separation space between the die assemblies than previously available devices. The compact force device embodiments described herein may, for example, be about 3 inches (7.6 cm) wide and have a stroke (length between minimum and maximum extension of the threaded shaft, as described below) of more than 3 inches, for example 4 inches (10.2 cm) or more. The embodiments of the present invention may be larger or smaller, and the approximate dimensions given above are for relative scale purposes. Additionally, the force generated by the compact force device of the embodiments described herein may exceed 1,000 pounds (453.6 kg).

[0028] FIG. 6 illustrates an exemplary embodiment of two adjacent semi-continuous casting mold assemblies 200 with two compact force devices 300 positioned between the two mold assemblies and applying forces to adjacent sidewall assemblies (210, 220) thereby imparting curvature to the mold sidewall assemblies. Additionally, a compact force device 305 disposed between the mold frame 205 and the mold sidewalls (210, 220) imparts a bend to each of the corresponding mold sidewalls. As discussed above, to increase the efficiency of a casting operation, it is advantageous to minimize the space between adjacent mold assemblies to maximize casting pit utilization. Although the exemplary embodiments described herein are used within a semi-continuous casting operation, the compact force device embodiments described herein may be used in a variety of applications, particularly where workspace is a design factor or consideration. For example, embodiments may be employed when separating objects, such as objects with a relatively tight interference fit, such as separating a ball joint from a control arm in an automotive application.

[0029] The compact force apparatus of the embodiment is used to apply equal and opposite forces to either side of the apparatus. When placed between two mold assemblies as described above, the forces on the apparatus are balanced and the apparatus remains substantially stationary. The embodiment can be further supported in a configuration in which one side of the compact force apparatus is attached to a stationary object, and a force applied to the other side induces motion.

[0030] FIG. 7 illustrates an example embodiment of a compact force device 300 of an example embodiment. The illustrated embodiment includes a gear box 305 from which a first shaft 310 and a second opposing shaft 315 extend as a first pair, along with a third shaft 320 and a fourth opposing shaft 325 as a second pair. Although the illustrated embodiment includes two pairs of opposing shafts, embodiments can have more or fewer pairs of shafts. Each pair of shafts is generally parallel to the other pair of shafts to allow for equal application of forces as described herein. The example embodiment of FIG. 7 further includes a first mounting plate 330 and a second mounting plate 335. However, the mounting plates are merely exemplary of a mounting mechanism through which the compact force device 300 may be secured between the objects to which it is applying the force.

[0031] The mounting plates engage the threaded shafts in a manner that holds them rotatably fixed so that they do not rotate about their axes. Although the mounting plates are shown to be substantially parallel to a plane passing through the center of the gearbox in the illustrated embodiment, this is not necessary. For example, when using a continuous casting mold operation, a taper may be provided in the mold sidewalls such that the top edge of the first mounting plate 330 is closer to the top edge of the second mounting plate 335 than the distance between the bottoms of the first and second mounting plates. As will be explained further below, if the thread pitches of the threaded shafts are equal in threads per inch, the relative angle of the first mounting plate 330 and the second mounting plate 335 is maintained as the plates are moving. Opposing shafts of a pair may also exert different forces than opposing shafts of other pairs. For example, in embodiments where a taper is provided in the mold side walls, the pair of shafts (first shaft 310 and second shaft 315) that provides a large deflection to the mold side walls can also exert a larger force than the lower pair of shafts (e.g., third shaft 320 and fourth shaft 325), even when the opposing shafts in the pair are moving together.

[0032] Also shown is a drive socket 340 that is configured to rotate such that the opposing pair of shafts extend or retract depending on the direction of rotation of the drive socket 340. The drive socket 340 in the illustrated embodiment has a keyway, e.g., a hexagonal keyway, although the keyway may be of any contour shape that allows a positive rotational force to be provided by the key shaft engaging the keyway. The keyway may pass through the worm gear such that the compact force device 300 can be positionably moved laterally along the key shaft while the key shaft remains engaged with the keyway and the drive socket 340 can rotate with the rotation of the key shaft. The compact force device embodiment further includes an optional through hole 342, the function of which is described further below. The mechanism for retracting and extending the pair of shafts is described in more detail below.

[0033] FIG. 8 shows the compact force application device of FIG. 7 in a perspective view with the housing of the gear box 305 omitted for ease of understanding. As shown, each of the shafts belonging to the shaft pair is supported by a bearing, for example, bearing 316 for the second shaft 315 and bearing 321 for the third shaft 320 visible in FIG. 8. The worm gear 345 is driven by the drive socket 340. The worm gear 345 is engaged with a first worm wheel gear 350 and a second worm wheel gear 355. The teeth of the worm wheel gears are not shown properly but will be apparent to one skilled in the art. Rotation of the drive socket 340 causes each of the first worm wheel gear 350 and the second worm wheel gear 355 to rotate in opposite directions.

[0034] FIG. 9 shows a cross section of the worm gear 345, the first worm wheel gear 350 and the second worm wheel gear 355 when positioned in a gearbox. Also shown are a first gear shaft 400 and a second gear shaft 430. A first end 410 of the first gear shaft 400 has a relatively small diameter threaded bore 410. A second end 415 of the first gear shaft has a relatively large diameter threaded bore 415. Similarly, a first end 420 of the second gear shaft 430 has a relatively small diameter threaded bore and a second end 425 of the second gear shaft has a relatively large diameter threaded bore. The first gear shaft 400 is fixed to the first worm wheel gear 350 and the second gear shaft 430 is fixed to the second worm wheel gear 355. When the worm wheel gear 355 rotates, the first worm wheel gear 350 and the second worm wheel gear 355 are driven. Then, the worm wheel gears fixed to the gear shafts respectively drive the gear shafts.

[0035] FIG. 10 shows the cross section of FIG. 9 with the shaft pair included and engaged with the gear shaft. Each of the shafts of the shaft pair has an external thread. The first shaft 310 has a relatively small diameter that is equal to the diameter of the threaded hole 410 and an external thread that is complementary to the threaded hole 410. As shown in FIG. 10, the first shaft 310 is in threaded engagement with the threaded hole 410. Similarly, the third shaft 320 has a relatively small diameter that is equal to the diameter of the threaded hole 420 and an external thread that is complementary to the threaded hole 420. The second shaft 315 has a relatively large diameter that is complementary to the diameter of the threaded hole 415 and an external thread that is complementary to the threaded hole 415. Similarly, the fourth shaft 325 has a relatively large diameter that is complementary to the diameter of the threaded hole 425 and an external thread that is complementary to the threaded hole 425. FIG. 10 shows a first shaft 310 threadedly engaged with threaded hole 410, a second shaft 315 threadedly engaged with threaded hole 415, a third shaft 320 threadedly engaged with threaded hole 420, and a fourth shaft threadedly engaged with threaded hole 425.

[0036] As the worm gear 345 rotates to drive the first worm wheel gear 350 and the second worm wheel gear 355 in opposite rotational directions, each of the shafts remains rotationally fixed while the first gear shaft 400 and the second gear shaft 430 rotate with their respective worm wheel gears. With the externally threaded shaft held rotationally fixed and the gear shafts rotating, the externally threaded shaft moves along the internally threaded bore. Referring now to the first gear shaft 400, in response to the first gear shaft rotating in a first direction, the first shaft 310 and the second shaft 315 are attracted to each other as the threads of the gear shafts' threaded bores rotate about the rotationally fixed first and second shafts. In response to the first gear shaft rotating in the second direction, the first shaft 310 and the second shaft 315 are both driven away from each other as the threads of the threaded holes in the gear shafts rotate about the rotationally fixed first and second shafts.

[0037] The second gear shaft 430 is rotated relative to the first gear shaft 400 as shown in Figures 9 and 10. This results in the same movement of the third shaft 320 and the fourth shaft 325 relative to the first shaft 310 and the second shaft 315 as a result of the counter rotation of the second gear shaft 430 relative to the first gear shaft 400. Thus, when the worm gear 345 is rotating, the first shaft 310 moves toward or away from the second shaft 315 in the same direction as the third shaft 320 moves toward or away from the fourth shaft 325. Furthermore, the thread pitches of the shafts and their respective threaded holes are equal, so that a single rotation of the gear shafts causes the first shaft 310 and the second shaft 315 to move toward or away from each other the same distance. The same is true for the third shaft 320 and the fourth shaft 325 and their threads, which causes the first mounting plate 330 and the second mounting plate 335 shown in Figure 8 to move towards and away from each other at a consistent rate and remain at equal displacement relative to the gearbox 305 between the shafts on the same side of the gearbox (e.g., the first shaft 310 and the fourth shaft 325).

[0038] According to some embodiments, the first shaft 310 and the third shaft 320 may be located on the same side of the gearbox. In such an embodiment, the first shaft 310 and the third shaft 320, as they are identical in the above-mentioned embodiment, with the relatively small diameter threaded shaft located on the same side, are not interchangeable parts, since the first gear shaft 400 and the second shaft 430 rotate in opposite directions. In contrast, if the first shaft 310 and the third shaft 320 are provided on the same side of the gearbox, the threads of the shafts must be opposite to each other, so that the opposite rotation of the gear shafts on which the first and third shafts move will subsequently drive the first and third shafts in the same direction. The same is true for the second shaft 315 and the fourth shaft 325, which are located on the same side of the gearbox but are not interchangeable. The gear shafts would also require threads to accommodate the unique threaded shafts of such an exemplary embodiment. While such configurations are possible, the illustrated embodiment results in fewer unique parts for the compact force device because the first shaft 310 and third shaft 320 are interchangeable, as are the second shaft 315 and fourth shaft 325.

[0039] The thread pitch of the threaded shaft (and complementary threaded bore) may be configured with the thread pitch of the worm wheel gear to provide a particular degree of force. A finer thread pitch allows a larger force to be applied to the threaded shaft, and more rotations result in a smaller degree of motion. The thread pitches of the threaded shaft, threaded bore, worm gear, and worm wheel gear may be configured to provide a particular magnitude at the threaded shaft for force as input and rotation as input at the worm gear. Optionally, while the above-described embodiments include the same thread pitch for each of the threaded shafts with the same number of threads per inch, the embodiments described herein may use different thread pitches between different threaded shafts to provide different degrees of motion. For example, for the continuous casting mold operation described above, the first shaft 310 and the second shaft 315 may have a thread pitch with fewer threads per inch than the third shaft 320 and the fourth shaft 325. Such an embodiment changes the taper of the mold sidewalls when the compact force device acts against them, causing the first and second shafts to produce a greater motion per revolution than the third and fourth shafts.

[0040] 11 shows a cross section similar to that of FIG. 10, in which a first shaft 310, a second shaft 315, a third shaft 320, and a fourth shaft 325 are depicted together. As shown, the second shaft 315 has a void 515 and the fourth shaft 325 also has a void 525. When the first shaft 310 and the second shaft 315 are drawn together, the first shaft 310 is received within the void 515 of the second shaft 315. Similarly, when the third shaft 320 and the fourth shaft 325 are drawn together, the third shaft 320 is received within the void 525 of the fourth shaft 325. This configuration allows the force applied by the first shaft 310 and the second shaft 315 to be coaxial while allowing the stroke of the first shaft 310 and the second shaft 315 to be greater than if the shafts were not configured to nest within one another as shown in Figure 11. Figure 12 shows a compact force applicator 305 having a gearbox 300 with the first shaft 310 retracted within the gearbox and received within the second shaft 315 (shown in Figure 11) and the second shaft 320 retracted within the gearbox and received within the fourth shaft 325.

[0041] The shaft pairs (e.g., first shaft 310 / second shaft 315 and third shaft 320 / fourth shaft 325) are coaxial so that the forces exerted by the force devices are equal and opposite. The coaxial forces exerted by the compact force devices as described herein ensure that the forces are equal, opposite, and balanced across the gearbox of the exemplary embodiment. This balance allows the compact force devices described herein to float between the mold side walls without the need for load-bearing structures to secure the force devices in place. This further reduces the complexity of the mold assemblies and allows them to be placed relatively close to each other relative to larger force devices and force devices that require rigid superstructures to keep the force devices in place.

[0042] While the illustrated embodiment includes two pairs of opposed shafts, one, three or any number of pairs of shafts may be included without departing from the fundamental principles of the compact force device described herein. Additionally, while the exemplary embodiment described above is employed in a semi-continuous casting operation, the compact force device embodiments described herein may be used in a wide variety of applications. It should be understood that the exemplary use cases described herein are not limitations of the compact force device of the exemplary use cases.

[0043] The compact force device of the above-mentioned exemplary embodiment can be used between objects applying equal and opposite forces by opposing shafts. However, in the exemplary embodiment of Figs. 5 and 6, the compact force device 305 is provided between a substantially rigid mold frame 205 and the mold side wall. In such exemplary embodiment, the shafts on one side of the compact force device (e.g., the second shaft 315 and the third shaft 320) can be removed. This can be accomplished by removing the first mounting plate 330 shown in Fig. 8 and disengaging the second shaft 315 and the third shaft 320 from their respective gear shafts. The compact force device can then be secured to the mold frame 205 with the first shaft 310 and the fourth shaft 325 attached to the mold side wall. In this way, the stroke is half of what the compact force device can perform, but the mold frame remains stationary, so that a full stroke is not necessarily required.

[0044] The driving force behind the compact force device may in some embodiments be the manual rotation of the worm gear, for example using the drive socket 340. Optionally, the drive socket may be driven automatically, for example by an electric motor controlled by a controller, which determines the degree of motion and / or force required from the compact force device. Two or more compact force devices may be mechanically coupled to be driven at the same speed while providing the same degree of motion and force application between them. According to some embodiments, feedback may be provided to the controller controlling the drive of the worm gear. The feedback may be in the form of the degree of motion imparted by the compact force device, for example the motion of the mold sidewall in the above example. Optionally, the feedback may be in the form of an applied force, for example a force measured with a stress / strain gauge. The feedback may be used to indicate when the worm gear should be driven in a first direction or the opposite direction, or when to hold a particular position.

[0045] The compact force device embodiments described herein can be further embodied in a system that can provide motion to two or more compact force devices while also using a prime mover to allow repositioning of the compact force devices. FIG. 13 shows an exemplary embodiment of three compact force devices, including a first device 550, a second device 560, and a third device 570. The configuration shown in FIG. 13 can include a configuration between two adjacent side walls of a mold similar to the exemplary embodiment described above. As shown, the drive socket 340 includes a keyway that passes through the worm gear of each compact force device. The second device 560 is shown rotated 180° relative to the first device 550 and the third device 570. The first drive shaft 555 is shown passing through the drive socket 340 of the first device and the drive socket 340 of the third device. However, the first drive shaft 555 passes through the through hole 342 of the second device 560. In response to rotation of the first drive shaft 555, the worm gear of the first device 550 and the worm gear of the third device 570 are driven to impart motion to the shafts of the respective devices. However, when the first drive shaft passes through the through hole 342 of the second device 560, it does not engage the worm gear and the shaft of the second device does not move in response to rotation of the first drive shaft. The second drive shaft 565 passes through the through hole 342 of the first device 550 and the third device 570 but is shown engaged in the drive socket 540 of the second device 560. Thus, in response to rotation of the second drive shaft 565, the worm gear of the second device 560 rotates and imparts motion to the shaft of the second device while the worm gears of the first device 550 and the third device 570 are not engaged with the second drive shaft 565. In this manner, the motion of the shafts of the first device 550 and the third device 570 remains coordinated and is driven by the first drive shaft 555 while the second device 560 moves independently based on the second drive shaft 565. This configuration allows for the application of different forces near the center of the mold sidewall than away from the center.Additionally, the motion can be provided by a motor controlled by a controller during operation of the continuous casting mold.

[0046] The controller of the example embodiment may receive instructions of a motion or force to be applied using the compact force application device of the example embodiment, for example, from a user or a separate computing device. The controller of the example embodiment is shown in a simplified diagram in FIG. 14. As shown, in the example embodiment, the controller 400 may include a processing circuit 610, and in some embodiments may further include a memory 620. The processing circuit may be in communication with, include, or otherwise control a user interface 630 and / or a communication interface 640. Thus, the processing circuit may be embodied as a circuit chip (e.g., an integrated circuit chip) configured (e.g., by hardware, software, or a combination of hardware and software) to perform the operations described herein.

[0047] The processing circuit 610 can be embodied in a wide variety of ways. For example, the processor can be embodied as various processing means, such as a microprocessor or other processing element, a coprocessor, a controller, or other computing or processing device including integrated circuits, such as an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), etc. Although illustrated as a single processor, it is understood that the processor may be comprised of multiple processors. The multiple processors may be in operative communication with each other and collectively configured to perform one or more functions of a system for handling, storing, transporting, or distributing various information as described herein. The multiple processors may be embodied on a single computing device or may be distributed across multiple computing devices. In some example embodiments, the processor may be configured to execute instructions stored in a memory or otherwise accessible to the processor. Thus, whether implemented in hardware or a combination of hardware and software, a processor may represent an entity (e.g., in circuitry - physically embodied in the form of a processing circuit) capable of performing operations in accordance with an embodiment of the present invention. Thus, for example, where a processor is embodied as an ASIC, FPGA, etc., the processor may be hardware specially configured to perform the operations described herein. Alternatively, as another example, where a processor is embodied as an executor of software instructions, the instructions may specially configure the processor to perform one or more operations described herein.

[0048] In some example implementations, the memory 620 may include one or more non-transitory memory devices, such as volatile and / or non-volatile memories, which may be either fixed or removable. In this regard, the memory 620 may comprise a non-transitory computer-readable storage medium. As will be appreciated, although the memory 620 is shown as a single memory, the memory may include multiple memories. The multiple memories may be embodied on a single computing device or may be distributed across multiple computing devices. The memory may be configured to store information, data, applications, instructions, and / or the like to enable embodiments of the present invention to perform various functions according to one or more example embodiments. For example, the memory may be configured to buffer input data for processing by the processor. Additionally or alternatively, the memory may be configured to store instructions executable by the processor. As yet another alternative, the memory may include one or more databases that may store various files, content, or data sets. Among the contents of the memory, applications may be stored executable by the processor to perform functions associated with each corresponding application.

[0049] The user interface 630 of the example embodiment may be in communication with the processing circuitry to receive user input indications at the user interface and / or provide audible, visual, mechanical, or other output to the user. The user interface may thus include, for example, a user input interface 630, such as a keyboard, a mouse, a joystick, a display, a touch screen display, a microphone, a speaker, and / or other input / output mechanisms. The user interface thus provides a means for enabling user control of the embodiments of the present invention in some example embodiments. In some example embodiments, one or more aspects of the user interface may be implemented on a user terminal. Regardless of implementation, the user interface may thus provide input and output means for facilitating movement of a compact force application device as described herein.

[0050] The communications interface 640 may include one or more interface mechanisms to enable communication with other devices and / or networks. In some cases, the communications interface may be any means, e.g., device or circuitry, embodied in either hardware or a combination of hardware and software, configured to receive data from and / or send data to a network and / or any other device or module in communication with the processing circuit. Thus, the communications interface may include, for example, supporting hardware and / or software to enable communications via cable, digital subscriber line (DSL), Universal Serial Bus (USB), Ethernet, or other methods.

[0051] The controller 600 of the example embodiment may be configured to control various aspects of the compact force device as described herein. In the above-described implementation in a semi-continuous casting process, the controller may control the motion of the compact force device to impart a particular curvature to the sidewalls of the die assembly based on various inputs. For example, the alloy being cast, the casting speed, the temperature of the casting material, etc. may be input to define the curvature and curvature movement of the die during the casting operation, where the curvature and curvature movement are imparted by the compact force device as controlled by the controller 400 described herein.

[0052] FIG. 15 is a flow diagram of a process using a compact force device of an example embodiment. As shown, a compact force device is positioned between a first mold sidewall of a first mold and a second mold sidewall of a second mold, as shown at 710. A rotational input is provided to the compact force device, as shown at 720. This rotational input may be a manual input (e.g., rotating a wheel, tool, leveler, etc.) or an automatic input (e.g., using an electric motor connected to a controller as described above). The first mold sidewall is moved relative to the second mold sidewall in response to the rotational input, as shown at 730. This movement may be controlled by the controller 600 using an input to be applied to the mold sidewall, for example, a desired curvature. This method embodiment may include multiple compact force devices between the mold sidewalls, each with an independent control scheme to establish a desired curvature that may require displacements at different compact force devices to be different from each other.

[0053] Many variations and other embodiments of the inventions described herein will be apparent to one skilled in the art having the benefit of the teachings provided in the foregoing descriptions and the associated drawings. It is therefore to be understood that the invention is not limited to the specific embodiments disclosed, and modifications and other embodiments are intended to be included within the scope of the invention as defined by the appended claims. Although specific terms are employed herein, such terms are used in a generic and descriptive sense only and are not intended to be limiting of the invention.

Claims

1. 1. A force application device comprising: Worm gear and a worm wheel gear engaged with the worm gear; a gear shaft coaxial with the worm wheel gear and rotatably coupled to the worm wheel gear; a first threaded bore disposed near a first end of the gear shaft; a second threaded bore disposed near a second end of the gear shaft opposite the first end; a first threaded shaft received by the first threaded bore; and a second threaded shaft received by the second threaded bore; the first threaded shaft and the second threaded shaft are configured to move toward or away from each other in response to rotation of the worm gear causing the worm wheel gear and thus the gear shaft to rotate relative to the first threaded shaft and the second threaded shaft.

2. 2. The apparatus of claim 1, wherein the second threaded shaft has a void, and in response to the first threaded shaft and the second threaded shaft moving toward one another, the first threaded shaft is received within the void of the second threaded shaft.

3. 3. The apparatus of claim 2, wherein in response to the first threaded shaft and the second threaded shaft moving toward or away from one another, the first threaded shaft exerts a first force on a first object coupled to the first threaded shaft and the second threaded shaft exerts a second force on a second object coupled to the second threaded shaft, the first force and the second force being equal and opposite in magnitude.

4. The apparatus of claim 3 , wherein the first threaded shaft and the second threaded shaft are coaxial.

5. The apparatus of claim 1 , wherein the first threaded shaft and the second threaded shaft are held in rotatable fixed relation.

6. The worm wheel gear is a first worm wheel gear, the gear shaft is a first gear shaft, and the apparatus comprises: a second worm wheel gear engaged with the worm gear; a second gear shaft coaxial with and rotatably coupled to the second worm wheel gear; a third threaded bore disposed near the first end of the second gear shaft; and a fourth threaded bore disposed near the second end of the second gear shaft; and a third threaded shaft received by the third threaded bore; and a fourth threaded shaft received by the fourth threaded bore; 2. The apparatus of claim 1, wherein the third threaded shaft and the fourth threaded shaft are configured to move toward or away from each other upon rotation of the second worm wheel gear and thus the worm gear causing the second gear shaft to rotate relative to the third threaded shaft and the fourth threaded shaft.

7. 7. The apparatus of claim 6, further comprising a gear box housing the worm gear, the first worm wheel gear, the first gear shaft, the second worm wheel gear, and the second gear shaft, the first threaded shaft and the fourth threaded shaft being disposed on a first side of the gear box, and the second threaded shaft and the third threaded shaft being disposed on a second side of the gear box.

8. 8. The apparatus of claim 7, wherein the first threaded shaft, the second threaded shaft, the third threaded shaft, and the fourth threaded shaft each move toward or away from the gear box in unison at the same speed in response to rotation of the worm gear.

9. 9. The apparatus of claim 8, wherein a first object is attached to the first and fourth threaded shafts, a second object is attached to the second and third threaded shafts, the first and second threaded shafts apply a first force between the first and second objects in response to a first rotation of the worm gear, and the third and fourth threaded shafts apply a second force between the first and second objects in response to a second rotation of the worm gear, the first force being different from the second force.

10. 2. The apparatus of claim 1, wherein the first threaded hole has a first thread pitch and a first diameter and the second threaded hole has a second thread pitch and a second diameter, the first thread pitch being the same as the second thread pitch and the first diameter being different than the second diameter.

11. The apparatus of claim 9 , wherein the second threaded shaft is provided with a cavity, the cavity having a diameter greater than the first diameter.

12. 1. A force application system comprising: a gear shaft having a first threaded bore near a first end and a second threaded bore near a second end; a first threaded shaft received in the first threaded bore, the first threaded shaft having a first diameter; a second threaded shaft received in the second threaded bore, the first threaded shaft having a cavity, the cavity having a cavity diameter greater than the first diameter; the first threaded shaft and the second threaded shaft approach one another in response to rotation of the gear shaft relative to the first threaded shaft and the second threaded shaft in a first direction, and the first threaded shaft is received within the void as the first threaded shaft and the second threaded shaft continue to approach one another.

13. a worm wheel gear attached to the gear shaft; The system of claim 12 , further comprising a worm gear engaged with the worm wheel gear, the worm gear configured to rotate the worm wheel gear in response to rotation of the worm gear.

14. 14. The system of claim 13, wherein the first threaded shaft and the second threaded shaft are coaxial and extend along a first axis, the first axis being perpendicular to an axis of rotation of the worm gear.

15. The system of claim 14 , wherein rotation of the worm gear in a first direction causes the first threaded shaft to approach the second threaded shaft.

16. 1. A semi-continuous casting system comprising: A mould frame and a first mold assembly supported within the mold frame and having a first mold sidewall; a second mold assembly supported within the mold frame and having a second mold sidewall positioned adjacent to the first mold sidewall; and one or more compact force fixtures disposed between the first mold sidewall and the second mold sidewall, each of the one or more compact force fixtures comprising: It has a worm gear, a worm wheel gear engaged with the worm gear; a gear shaft rotatably fixed to the worm wheel gear, the gear shaft having a first end with a first threaded bore and a second end with a second threaded bore; a first threaded shaft engaged with the first threaded hole and attached to the first mold side wall; a second threaded shaft engaged with the second threaded hole and attached to the second mold side wall; The one or more compact force devices move the first and second mold side walls toward or away from one another in response to rotation of the worm gear.

17. 17. The system of claim 16, wherein the second threaded shaft has a void, and in response to the first threaded shaft and the second threaded shaft moving toward one another, the first threaded shaft is received within the void of the second threaded shaft.

18. 18. The system of claim 17, wherein in response to the first threaded shaft and the second threaded shaft moving toward or away from one another, the first threaded shaft exerts a first force on the first mold sidewall and the second threaded shaft exerts a second force on the second mold sidewall, the first force and the second force being equal and opposite in magnitude.

19. The system of claim 18 , wherein the first threaded shaft and the second threaded shaft are coaxial.

20. 17. The system of claim 16, wherein a maximum stroke distance is defined as the longest distance that the first threaded shaft moves relative to the second threaded shaft, the maximum stroke distance being greater than a length of the gear shaft along an axis of the gear shaft.

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