Patent ID: 12240422

DETAILED DESCRIPTION

All ranges and ratio limits disclosed herein may be combined. It is to be understood that unless specifically stated otherwise, references to “a,” “an,” and/or “the” may include one or more than one and that reference to an item in the singular may also include the item in the plural.

The detailed description of various embodiments herein makes reference to the accompanying drawings, which show various embodiments by way of illustration. While these various embodiments are described in sufficient detail to enable those skilled in the art to practice the disclosure, it should be understood that other embodiments may be realized and that logical, chemical, and mechanical changes may be made without departing from the spirit and scope of the disclosure. Thus, the detailed description herein is presented for purposes of illustration only and not of limitation. For example, the steps recited in any of the method or process descriptions may be executed in any order and are not necessarily limited to the order presented. Furthermore, any reference to singular includes plural embodiments, and any reference to more than one component or step may include a singular embodiment or step. Also, any reference to attached, fixed, connected, or the like may include permanent, removable, temporary, partial, full, and/or any other possible attachment option. Additionally, any reference to without contact (or similar phrases) may also include reduced contact or minimal contact. Cross hatching lines may be used throughout the figures to denote different parts but not necessarily to denote the same or different materials.

Typical lifting devices, such as linear trailer jacks, operate using a constant thread pitch sized to obtain sufficient mechanical advantage to lift a heavy load, such as a trailer. In that regard, as a smaller thread pitch increases mechanical advantage relative to a larger thread pitch, many available linear trailer jacks use a constant, small thread pitch. However, the gain in mechanical advantage is offset by the increase in the number of rotations of an input device (e.g., a handle) needed to extend (translate) the linear trailer jack. In this manner, conventional linear trailer jack may provide the mechanical advantage desired to lift a trailer but at the expense of time consuming, and bothersome, turning.

Thread pitch, as used herein, is generally defined as the distance between threads on a threaded coupling, such as that found on a screw, lead screw, or jack screw. Thread count, expressed for example as threads per inch, is generally defined as the number of threads per inch of linear distance on a threaded coupling, such as that found on a screw, lead screw, or jack screw. In that regard, thread pitch and thread count are related, both expressing the spacing of threads about a screw, lead screw, or jack screw.

The terms “coarse nut” and “fine nut” are used herein to refer to threaded devices having helical ridges or threads disposed on an inner diameter surface thereof. As the name implies, a coarse nut has fewer threads per inch than a fine nut. In this regard, the terms “coarse” and “fine” each refer to a thread pitch of the respective nut.

Systems and methods for a two-speed lifting device—such as a linear trailer jack—are provided herein. A lifting device of the present disclosure generally comprises a high-speed assembly and a low-speed assembly. The high-speed assembly generally comprises a screw mechanism comprising a nut threadedly coupled to a screw. In various embodiments, the screw rotates and the nut translates. The screw and nut are threadedly coupled for translating the rotational force to a linear force. The low-speed assembly also comprises a nut threadedly coupled to a screw. A thread pitch of the high-speed assembly is greater than a thread pitch of the low-speed assembly, in various embodiments. In this manner, when driven by a common shaft and/or at the same revolutions per unit time, the high-speed assembly causes the lifting device to extend a greater linear distance per rotation of a shaft than the low-speed assembly.

In this manner, the high-speed assembly causes more linear extension per rotation and thus reduces the number of rotations needed to lower or raise the lifting device. This reduces or eliminates the wasted time incurred if no such high-speed assembly existed. However, in response to the lifting device beginning to touch the ground, and mechanical advantage now becomes more important, in various embodiments, the high-speed assembly is disengaged, for example, automatically disengaged. Thus, in response to the lifting device contacting a ground surface, a force is reacted into the high-speed assembly, thereby moving a moveable member of the high-speed assembly from a first position to a second position and disengaging the high-speed assembly from being drivably coupled with the shaft and/or other motive rotational force. With the moveable member of the high-speed assembly in the second position, only the low-speed assembly is driven in response to rotation of the shaft, thereby benefiting from the mechanical advantage of the low-speed assembly, which has a smaller thread pitch than the high-speed assembly. In this manner, lifting devices of the present disclosure may quickly and efficiently extend in overall length, reducing the number of turns required to reach a ground surface, while still providing the mechanical advantage to lift heavy loads. In various embodiments, this transition occurs without any additional action and thus improves ease of use and reduces overall time needed for operation. In this manner, lifting devices of the present disclosure may automatically switch from a high-speed mode to a low-speed mode in response to the ground force being reacted through the lifting device (i.e., in response to contacting the ground as the jack is extended).

With reference toFIG.1, a trailer120partially supported on a ground surface190by a lifting device100is illustrated, in accordance with various embodiments. Lifting device100may be coupled to a front end of the trailer120. Lifting device100may be generally vertically oriented when supporting the front end of the trailer120. Although illustrated coupled to a utility type trailer, lifting devices of the present disclosure may be utilized on any trailer or vehicle where support is desired, for example, with a camper, recreational vehicle, toy hauler, boat, or any other device capable of being towed as a trailer.

With reference toFIG.2, an exploded view of a lifting device200is illustrated, in accordance with various embodiments. Lifting device200may be a linear jack. Lifting device200may generally comprise an outer tube202, a high-speed assembly generally comprising a first rotating screw204, a coarse nut206, and a first sleeve208, and a low-speed assembly generally comprising a second rotating screw210, a fine nut212, and a second sleeve214. The high-speed assembly may generally comprise a screw mechanism comprising the first rotating screw204threadedly coupled to the coarse nut206, in the manner of a leadscrew or jack screw. In various embodiments, the first sleeve208is configured to translate together with the coarse nut206. The first sleeve208can be a translating sleeve configured to translate with respect to the outer tube202. In various embodiments, the first sleeve208is secured from rotating with respect to the outer tube202. The low-speed assembly may generally comprise a screw mechanism comprising the second rotating screw210threadedly coupled to the fine nut212. The second sleeve214is configured to translate together with the fine nut212. The second sleeve214can be a translating sleeve configured to translate with respect to the outer tube202and/or the first sleeve208. In various embodiments, the second sleeve214is secured from rotating with respect to the outer tube202and/or the first sleeve208. The fine nut212can be coupled to an upper end of the second sleeve214, e.g., via a threaded connection, fasteners, and/or a metal joining process, such as welding, brazing, soldering, etc. The fine nut212can include a keyway213whereby the fine nut212and the second sleeve214are secured from rotating with respect to the first sleeve208. For example, the fine nut212and the second sleeve214can be coupled together via a keyed connection (i.e., the keyway212and an associated key disposed in an inner diameter surface of the second sleeve214) that permits translating motion of the fine nut212with respect to the second sleeve214, but that mechanically blocks the fine nut212from rotating with respect to the second sleeve214.

The outer tube202may define a centerline axis292. The outer tube202is hollow and is configured to telescopingly receive the first sleeve208and the second sleeve214. The first sleeve208may be disposed at least partially within the outer tube202. The first sleeve208may be hollow. The second sleeve214may be disposed at least partially within the first sleeve208. The second sleeve214may be hollow. The second rotating screw210may be disposed at least partially within the second sleeve214. The second rotating screw210may be hollow. The first rotating screw204may be disposed at least partially within the second rotating screw210. The first rotating screw204may be slidingly engaged with the second rotating screw210. The second rotating screw210can be configured to rotate together with the first rotating screw204about the centerline axis292. The inner dimension of the outer tube202may be greater than the outer dimension of the first sleeve208. The inner dimension of the first sleeve208may be greater than the outer dimension of the second sleeve214. The inner dimension of the second sleeve214may be greater than the outer dimension of the second rotating screw210. The inner dimension of the second rotating screw210may be greater than the outer dimension of the first rotating screw204. The outer tube202, the first sleeve208, the second sleeve214, the second rotating screw210, the coarse nut206, and the fine nut212can be coaxially aligned and/or substantially coaxially aligned, but in various embodiments coaxial alignment may not be present.

FIG.3AandFIG.3Bare side and section views, respectively, of the lifting device200in an assembled state and in a retracted position, in accordance with various embodiments.FIG.4is a section view of an upper portion of the lifting device200in the assembled state and in the retracted position, in accordance with various embodiments. With combined reference toFIG.2throughFIG.4, one end of the first rotating screw204may bear a handle216which may be used for rotating the first rotating screw204. The handle216can be removably coupled to an upper end of the first rotating screw204, which can aid in manufacturability and/or assembly of the lifting device200. The outer tube202can include a retaining member, such as a cap218coupled to an upper end thereof. The cap218can be coupled to the outer tube202, e.g., via a threaded connection, fasteners, and/or a metal joining process, such as welding, brazing, soldering, etc. The cap218may comprise a flange extending inward from an inner surface of outer tube202. The first rotating screw204can extend through the cap218. The first rotating screw204can be mounted to the outer tube202via the cap218.

In various aspects, and with particular focus onFIG.3B, a first washer220can be positioned at an outer surface of the cap218. The first rotating screw204can extend through the cap218and the first washer220. A lock ring224can be snapped in place on the first rotating screw204, for example received in a cylindrical groove disposed in the first rotating screw204, for providing a stopping surface to prevent the top end of the first rotating screw204from sliding through the cap218. The lock ring224can be removed to disassemble the lifting device200. The lock ring224can contact the first washer220. A bearing222can be located inside the outer tube202. The bearing222can be located at an inner surface of the cap218. The cap218can be sandwiched between the bearing222and the first washer220. The bearing222can be disposed between the cap218and the coarse nut206. In various embodiments, the bearing222can be coupled—e.g., press fit—to the cap218. The bearing222can secure the first rotating screw204in position and facilitate rotation of the first rotating screw204about the centerline axis292.

The coarse nut206can be threadedly coupled to the first rotating screw204. Thus, rotation of the first rotating screw204can cause the coarse nut206to translate with respect to the outer tube202and the first rotating screw204. The first sleeve208is coupled to the coarse nut206such that the first sleeve208translates together with the coarse nut206with respect to the outer tube202and the first rotating screw204between the retracted state (seeFIG.3B) and an extended state (seeFIG.8B). Stated differently, the high-speed assembly translates rotational motion of the first rotating screw204to linear motion of the coarse nut206and the first sleeve208.

The second rotating screw210can rotate together with the first rotating screw204. The first rotating screw204can drive rotating of the second rotating screw210. Stated differently, the first rotating screw204can be configured to impart a rotating force (e.g., a torque force) into the second rotating screw210to cause the second rotating screw210to rotate together with the first rotating screw204. In various embodiments, the second rotating screw210is slidingly coupled to the first rotating screw204, for example via a keyed connection or a splined connection. The second rotating screw210can include a head portion228and a shaft portion230. The head portion228can define an end of the second rotating screw210. The head portion228can comprise a flange that extends outwardly from the shaft portion230to interface with the first sleeve208. The flange can extend inwardly from the shaft portion230to interface with the first rotating screw204. With momentary reference toFIG.5, a perspective view of the second rotating screw210is illustrated, in accordance with various embodiments. The head portion228can define a center aperture502. The center aperture502can be sized and shaped to receive the first rotating screw204(seeFIG.6).

With momentary reference toFIG.6, a perspective view of the first rotating screw204is illustrated, in accordance with various embodiments. The first rotating screw204includes a threaded shaft604that is sized and shaped to be complementary to the center aperture502(seeFIG.5). With combined reference toFIG.5andFIG.6, the center aperture502is configured to receive the threaded shaft604. The head portion228can slide along the threaded shaft604as the second rotating screw210translates with respect to the first sleeve208between the retracted and extended positions. The center aperture502is sized and shaped to slidingly interlock with the threaded shaft605so that the second rotating screw210rotates together with the first rotating screw204. In this regard, the center aperture502can accommodate sliding motion of the head portion228with respect to the first rotating screw204, while also preventing rotation of the head portion228with respect to the first rotating screw204. A torque force applied to the first rotating screw204can be transmitted into the head portion228via the center aperture502and the threaded shaft605to cause the second rotating screw210to rotate together with the first rotating screw204. For example, the center aperture502can define a keyed connection between the threaded shaft604and the head portion228. Furthermore, although illustrated as having two opposing flat surfaces, the keyed connection between the center aperture502and the threaded shaft604may comprise various geometries such as a star shaped pattern, triangular, square, or any other geometry that slidingly interlocks the head portion228with the first rotating screw204. In various embodiments, the center aperture502can include grooves or splines for a splined connection between the first rotating screw204and the second rotating screw210. Any suitable connection is contemplated such that the first rotating screw204slidingly interlocks with the head portion228to impart rotational forces (i.e., torque) therebetween.

With particular focus onFIG.4, the second sleeve214is threadedly coupled to the second rotating screw210. The second sleeve214can be threadedly coupled to the second rotating screw210via the fine nut212. For example, the fine nut212can be coupled to an inner surface of the second sleeve214. Thus, rotation of the second rotating screw210causes the second sleeve214to translate with respect to outer tube202and the second rotating screw210. Stated differently, the low-speed assembly translates rotational motion of the second rotating screw210to linear motion of the second sleeve214.

In various embodiments, the first rotating screw204comprises helically extending grooves and/or threads232. In various embodiments, the second rotating screw210comprises helically extending grooves and/or threads234. The thread pitch of threads232may be greater than the thread pitch of threads234. Stated differently, the second rotating screw210may comprise more threads per inch (TPI) than the first rotating screw204. In various embodiments, the thread pitch of the threads232is between 101% and 1000% as large as the thread pitch of the threads234, though various embodiments, the thread pitch of the threads232is between 200% and 500% as large as the thread pitch of the threads234. In various embodiments, the thread pitch of the threads232is more than twice as large as the thread pitch of the threads234. In various embodiments, the thread pitch of the threads232is more than three times as large as the thread pitch of the threads234. In various embodiments, the thread pitch of the threads232is more than four times as large as the thread pitch of the threads234. It should be understood that the maximum thread pitch may be limited by the moment arm for torque applied to the first rotating screw204and may be limited to reduce the torque requirement for rotating the first rotating screw204below a desired threshold. In this manner, the high-speed assembly translates further and faster per rotation of the first rotating screw204than the low-speed assembly, causing the lifting device200to reach a ground surface faster than if the high-speed assembly were not present. Furthermore, in response to the lifting device200contacting a ground surface and the high-speed assembly disengaging from the first rotating screw204, the reduced thread pitch of the low-speed assembly takes advantage of the reduced torque required for extending the lifting device200.

In various embodiments, the thread pitch of the threads232may be between 0.1 millimeters (mm) and 304.8 mm (between 0.0039 inches and 12 inches) in accordance with various embodiments, between 1 mm and 101.6 mm (between 0.039 inches and 4 inches) in accordance with various embodiments, between 2 mm and 76.2 mm (between 0.0787 inches and 3 inches) in accordance with various embodiments, and/or between 4 mm and 50.8 mm (between 0.157 inches and 2 inches) in accordance with various embodiments.

The thread pitch of the threads234may be between 0.1 millimeters (mm) and 279.4 mm (between 0.0039 inches and 11 inches) in accordance with various embodiments, between 1 mm and 25.4 mm (between 0.039 inches and 1 inch) in accordance with various embodiments, between 1 mm and 6.35 mm (between 0.039 inches and 0.25 inches) in accordance with various embodiments, and/or between 2 mm and 3.175 mm (between 0.0787 inches and 0.125 inches) in accordance with various embodiments.

In operation, rotation of the first rotating screw204in a first rotational direction, e.g., via the handle216, causes the second rotating screw210to rotate therewith with respect to the outer tube202and the second sleeve214, thereby causing the second sleeve214to extend from the first sleeve208and the outer tube202(seeFIG.8AandFIG.8B). Conversely, rotation of the first rotating screw204in a second rotational direction (opposite the first rotational direction) causes the second rotating screw210to rotate therewith with respect to the outer tube202and the second sleeve214, which in turn causes the second sleeve214to retract into the first sleeve208(seeFIG.3AandFIG.3B).

Furthermore, in a first mode with a head portion236of the first sleeve208engaged (e.g., interlocked) with the coarse nut206, the coarse nut206can be restrained from rotating together with the first rotating screw204(e.g., via a dog clutch238) so that the coarse nut206translates with respect to the first rotating screw204and the outer tube202in response to rotation of the first rotating screw204. The first sleeve208can be coupled to the coarse nut206such that the first sleeve208translates with respect to the first rotating screw204and the outer tube202together with the coarse nut206. The second sleeve214and the second rotating screw210are mounted to the first sleeve208such that the second sleeve214and the second rotating screw210translate together with the first sleeve208with respect to the outer tube202and the first rotating screw204. In this regard, in the first mode, rotation of the first rotating screw204causes the first sleeve208and the second sleeve214to extend or retract (depending on the rotational direction of the first rotating screw204) with respect to the outer tube202via the high-speed assembly. In addition to extension and retraction of the second sleeve214with respect to the outer tube202via the high-speed assembly in the first mode, rotation of the first rotating screw204causes the second sleeve214to extend or retract (depending on the rotational direction of the first rotating screw204) with respect to the first sleeve208via the low-speed assembly.

In various embodiments, the dog clutch238includes a first plurality of teeth240(also referred to as dogs or dog gears) extending from the coarse nut206configured to interlock with a second plurality of teeth242(also referred to as dogs or dog gears) extending from the head portion236of the first sleeve208. When engaged (i.e., the first plurality of teeth240are interlocked with the second plurality of teeth242), the dog clutch238secures the coarse nut from rotating together with the first rotating screw204with respect to the outer tube202and the first sleeve208.

In various embodiments, the coarse nut206can comprise a hollow shaft portion244having a threaded inner diameter surface configured to interface with the threads232of the first rotating screw204. The thread pitch of the coarse nut206can be the same as the thread pitch of the first rotating screw204. A flange246can extend outwardly from the hollow shaft portion244. The flange246can be disposed at least partially in the first sleeve208. The hollow shaft portion244can extend through the head portion236of the first sleeve208. The head portion236can comprise a flange extending inward from the first sleeve208. The second plurality of teeth242can be disposed on the head portion236(e.g., on the flange extending inward from the first sleeve208). In various embodiments, the head portion236and the first sleeve208are two separate pieces coupled together. In various embodiments, the head portion236and the first sleeve208are formed as a single piece.

With reference toFIG.7, a perspective view of the upper end of the first sleeve208is illustrated, in accordance with various embodiments. The second rotating screw210can be rotatably coupled to the first sleeve208such that the second rotating screw210can rotate with respect to the first sleeve208, while maintaining longitudinal position with respect to the first sleeve208. Stated differently, the second rotating screw210can rotate with respect to the first sleeve208while translating together with the first sleeve208. The first sleeve208can include a first cutout248aand a second cutout248bthat define a tab250therebetween. A plurality of cutouts248and corresponding tabs250can be disposed circumferentially about the first sleeve208, in accordance with various embodiments. The tab250can extend inwardly from the main body of the first sleeve208to couple with the head portion228of the second rotating screw210. For example, with combined reference toFIG.5andFIG.7(also shown inFIG.4), the tab250can be received in a cylindrical groove252disposed in the head portion228of the second rotating screw210. The tab250can slidingly engage the head portion228at the cylindrical groove252such that the second rotating screw210can rotate with respect to the first sleeve208while simultaneously translating together with the first sleeve208. Stated differently, the first sleeve208and the second rotating screw210are configured to translate together. In various embodiments, translation of the first sleeve208with respect to the outer tube202drives translation of the second rotating screw210with respect to the outer tube202. The first sleeve208can be mechanically locked from translating along the centerline axis292with respect to the second rotating screw210via the cylindrical groove252. Stated differently, the first sleeve208can be slidingly interlocked with the second rotating screw210via the cylindrical groove252. Although illustrated as a tab250bent inward toward the centerline axis, the first sleeve208can be slidingly interlocked with the second rotating screw210via any suitable connection, such as a flange or ring member extending inwardly from the main body of the first sleeve208.

FIG.8AandFIG.8Bare side and section views, respectively, of the lifting device200in an assembled state and in an extended position, in accordance with various embodiments.FIG.8Cis an enlarged section view of the lifting device200ofFIG.8B. With combined reference toFIG.8AthroughFIG.8C, the first sleeve208is movable between a first position (seeFIG.3BandFIG.4) and a second position (seeFIG.8BandFIG.8C) with respect to the coarse nut206. In the first position, the dog clutch238is engaged (i.e., the first plurality of teeth240are interlocked with the second plurality of teeth242). In the second position, the dog clutch238is disengaged (i.e., the first plurality of teeth240are not interlocked with the second plurality of teeth242). With the head portion236of the first sleeve208disengaged from (i.e., the first plurality of teeth240are not interlocked with the second plurality of teeth242) the coarse nut206, the coarse nut206can rotate together with the first rotating screw204. The dog clutch238can disengage in response to the first sleeve208translating to the second position with respect to the coarse nut206. In various embodiments, the coarse nut206acts as a stopping surface for the second rotating screw210as the first sleeve208translates from the first position to the second position.

During operation, rotation of the first rotating screw204can cause the second sleeve214to extend. The second sleeve214can extend until the second sleeve214contacts a ground surface190(e.g., seeFIG.1andFIG.8B). In response to the second sleeve214contacting a ground surface, a reactive force (represented by arrow294) can be transmitted up through the second sleeve214, the second rotating screw210, and into the first sleeve208. This reactive force294can cause the first sleeve208to translate (e.g., upward) with respect to the outer tube202from the first position to the second position, thereby decoupling the first plurality of teeth240from the second plurality of teeth242(i.e., disengaging the dog clutch238). With the dog clutch238disengaged, the coarse nut206can begin to rotate together with the first rotating screw204and the second rotating screw210and no longer translates along the first rotating screw204.

In various embodiments, with the first sleeve in the second position, the head portion228of the second rotating screw210can contact the coarse nut206. With particular focus onFIG.8C, the head portion228can define an axially facing contact surface254configured to contact an axially facing contact surface256of the coarse nut206. The contact surface254can face a first direction parallel to the centerline axis292. The contact surface256can face a second direction parallel to the centerline axis292, opposite the first direction faced by the contact surface254. In various embodiments, the contact surface254and the contact surface256can each be oriented in a plane that is perpendicular to the centerline axis292. A torque force can be imparted from the second rotating screw210to the coarse nut206via the first contact surface254and the second contact surface256which causes the coarse nut206to rotate together with the first rotating screw204and the second rotating screw210. In this regard, the first contact surface254and the second contact surface256can form a “friction clutch” to impart rotational force from the second rotating screw210to the coarse nut206. In various embodiments, a surface roughness of the first contact surface254and/or the second contact surface256can be increased to increase friction between the second rotating screw210and the coarse nut206and to prevent the second rotating screw210from slipping with respect to the coarse nut206when in the second mode.

Although the coarse nut206and the first sleeve208are no longer translating with respect to the first rotating screw204and the outer tube202in the second mode, the second rotating screw210continues to rotate with the first rotating screw204so that the second sleeve214translates with respect to the second rotating screw210and the outer tube202. In this regard, in the second mode, rotation of the first rotating screw204causes the second sleeve214to extend or retract (depending on the rotational direction of the first rotating screw204) with respect to the outer tube202via the low-speed assembly.

In operation and with the first sleeve208in the second position (e.g., with a ground force294reacted through the first sleeve208), rotation of the first rotating screw204does not drive translation of the coarse nut206and the first sleeve208with respect to the outer tube202. In this regard, in the second mode, rotation of the first rotating screw204in the first rotational direction or the second rotational direction may cause only the second sleeve214(and not the first sleeve208) to translate with respect to the outer tube202and the first rotating screw204. Stated differently, the high-speed assembly (i.e., the first sleeve208) may be disengaged from operation in response to the first sleeve208being in the second position in the second mode. In this manner, in response to rotation of the first rotating screw204in the first direction, both the high-speed assembly (i.e., including the first sleeve208) and the low-speed assembly (i.e., including the second sleeve214) are driven to increase the overall length of lifting device200but, after reacting force from the ground through, for example, the second sleeve214, the second rotating screw210, and the first sleeve208, rotation of the first rotating screw204and the second rotating screw210is only imparted to the low-speed assembly and not the high-speed assembly.

With momentary reference toFIG.8B, as the overall length of the lifting device200is increased, the foot275of the lifting device200, which can be attached to a lower end of the second sleeve214or can be the lower end of the second sleeve214, may contact the ground surface190, thereby imparting the reactive force294from the ground surface190into the second sleeve214and thereby the second rotating screw210and the first sleeve208, which causes the first sleeve208to move with respect to the coarse nut206from the first position (i.e., disengaged from the coarse nut206) to the second position (i.e., engaged with the coarse nut206) thereby disengaging the dog clutch238and thereby disengaging the high speed assembly. In this regard, before the lifting device200has contacted a ground surface, the overall length of the lifting device200is quickly increased to reduce the overall number of rotations of the first rotating screw204needed to cause lifting device200to reach the ground surface190. In response to contacting the ground surface190, the high-speed assembly is decoupled from the first rotating screw204to take advantage of the mechanical advantage of the low-speed assembly. In this manner, time to operate is reduced relative to conventional designed and increased mechanical advantage is selectively activated.

Various components of the lifting device200may be made from a metal or metal alloy, such as cast iron, steel, stainless steel, austenitic stainless steels, ferritic stainless steels, martensitic stainless steels, titanium, titanium alloys, aluminum, aluminum alloys, galvanized steel, or any other suitable metal or metal alloy. In this regard, the outer tube202, the first sleeve208, the second sleeve214, the first rotating screw204, and/or the second rotating screw210may be made from a metal or metal alloy. It is contemplated that various components of lifting device200, such as the outer tube202, may be made from a fiber-reinforced composite material.

Benefits and other advantages have been described herein with regard to specific embodiments. 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 a practical system. However, the benefits, advantages, and any elements that may cause any benefit or advantage to occur or become more pronounced are not to be construed as critical, required, or essential features or elements of the disclosure. The scope of the disclosure is accordingly to be limited by nothing other than the appended claims, in which reference to an element in the singular is not intended to mean “one and only one” unless explicitly so stated, but rather “one or more.” Moreover, where a phrase similar to “at least one of A, B, or C” is used in the claims, it is intended that the phrase be interpreted to mean that A alone may be present in an embodiment, B alone may be present in an embodiment, C alone may be present in an embodiment, or that any combination of the elements A, B and C may be present in a single embodiment; for example, A and B, A and C, B and C, or A and B and C.

Systems, methods and apparatus are provided herein. In the detailed description herein, references to “various embodiments”, “one embodiment”, “an embodiment”, “an example embodiment”, etc., indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to affect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described. After reading the description, it will be apparent to one skilled in the relevant art(s) how to implement the disclosure in alternative embodiments.

Furthermore, no element, component, or method step in the present disclosure is intended to be dedicated to the public regardless of whether the element, component, or method step is explicitly recited in the claims. No claim element is intended to invoke 35 U.S.C. 112(f) unless the element is expressly recited using the phrase “means for.” As used herein, the terms “comprises”, “comprising”, or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.