|Publication number||US20080036239 A1|
|Application number||US 11/872,628|
|Publication date||Feb 14, 2008|
|Filing date||Oct 15, 2007|
|Priority date||Dec 2, 2002|
|Also published as||US7377362, US20040178399, US20070290183|
|Publication number||11872628, 872628, US 2008/0036239 A1, US 2008/036239 A1, US 20080036239 A1, US 20080036239A1, US 2008036239 A1, US 2008036239A1, US-A1-20080036239, US-A1-2008036239, US2008/0036239A1, US2008/036239A1, US20080036239 A1, US20080036239A1, US2008036239 A1, US2008036239A1|
|Inventors||Raymond Blodgett, Benjamin Fletes|
|Original Assignee||Blodgett Raymond W Jr, Fletes Benjamin J|
|Export Citation||BiBTeX, EndNote, RefMan|
|Referenced by (4), Classifications (11), Legal Events (1)|
|External Links: USPTO, USPTO Assignment, Espacenet|
This application claims priority to U.S. provisional application Ser. No. 60/430,425 filed on Dec. 2, 2002 entitled Removable Motor Brake For Use With Vehicle Slide Out, and U.S. provisional patent application Ser. No. 60/488,633 filed Jul. 18, 2003 entitled Safety Device for Load Bearing Nut, the contents of which are incorporated herein by reference.
In recreational vehicles and trailers (collectively, “RV's”), there is an ever present need for lifting mechanisms. While such lifting devices are rarely a necessity in RV's, they nevertheless maintain an important functional role with respect to space maximization, storage, and RV jacks.
Generally, RV's are constrained in size by their safety to drive, ease to maneuver, and affordability to the average traveler. Further, RV manufacturing companies have strived to provide the greatest number of features in the least amount of space. Consequently, improvements have been made over the years to increase the amount of usable space within the vehicle.
Some designs attempt to maximize space by way of lifting devices. Thus, to the extent feasible, the used space can be convertible for dual or even multiple purposes by lifting furniture or other objects out of the way.
One of the largest pieces of furniture within an RV is the bed. Many designers have maximized usable space by designing a bed that lowers and raises within an RV. Examples of such designs include U.S. Pat. Nos. 6,557,190, 6,231,114, 5,984,404, 3,266,062, all herein incorporated by reference.
Additionally, couches, chairs, tables and storage containers may be secured to a lift system to allow for convertible or dual use space. In a similar fashion, these objects may be secured to a lift mechanism which provides for a lowered, in use position, and a stowed, raised position.
Lifting devices are also valuable outside an RV in the form of a retractable RV jack as seen in U.S. Pat. No. 4,865,295, herein incorporated by reference. Retractable RV jacks are of invaluable use for support of such trailer vehicles as “fifth wheel” hitch RV trailers, allowing a user to maintain an upright position to the trailer after unhitching it from a truck. Retractable RV jacks are also useful for jack stability supports, as seen in U.S. Pat. No. 5,575,492, herein incorporated by reference. These retractable angle supports provide additional vertical and horizontal stability to an RV or RV trailer when in a nonmoving, parked position.
While functional, these lift devices are often highly specialize for their individual tasks. As specialization in design and parts increase, total cost of the lift mechanism also increases. Further, reliability may also suffer as a result of poor specialized designs and unproven component reliability.
Additionally, these lift devices often lack safety mechanisms integrated into these often heavy lifting mechanisms. Lack of such redundant safety mechanisms leaves the RV and all property in it at risk to damage in the event of lift failure. Further, users risk significant damage to themselves, family, or other visitors to the vehicle.
Lastly, these lift devices lack safety indicators to alert them to component failure on the lift devices. Such visual indicators would allow for quick and easy visual detection of failure of a primary component to the lifting device.
It is an object of the present invention to provide an improved lifting device capable of being adapted for a wide variety of purposes associated with an RV.
It is a further object of the present invention to provide an improved lifting device having a redundant safety feature which prevents damage in the event of lift component failure.
It is a further object of the present invention to provide an improved lifting device having visual safety indicators that warn a user of failure of components within the lift.
It is another object of the present invention to provide an improved lifting device for an RV that overcomes the disadvantages of the prior art. Further advantages will become apparent after reading the detailed description of the invention below.
The present invention achieves these objects by providing an improved lift mechanism according to the present invention. In one embodiment, the lift functions by way of an elongated, rotatably mounted acme screw. A bracket slides parallel to the acme screw, securing to an acme screw and an object to be lifted. The acme nut is threaded onto the acme screw and further held from rotation by the bracket. Thus, as the acme screw turns, it presses against the bracket, lifting or lowering both it and its payload.
RV Lifting Device
An improved RV lifting device is provided in accordance with the present invention. Generally speaking, the lifting device uses a captured acme nut threaded onto an elongated acme screw. By rotating the acme screw, the captured acme nut pushes a lifting bracket upward or downward. Such a lifting device may be utilized for a variety of different purposes, including raising and lowering furniture or acting as a jack stand for a fifth wheel trailer.
An additional bracket can been seen in this embodiment: the acme nut bracket 102. As the name implies, the acme nut bracket 102 serves to “capture” an acme nut 110 which has been threaded over the acme screw 106. In other words, the acme nut bracket 102 prevents the acme nut 110 from freely rotating when the acme screw 106 rotates, thus allowing the acme nut 110 to travel along the length of the acme screw 106 during rotation. The acme bracket 102 further allows this embodiment to lift a desired piece of furniture, portion of an RV, or other object associated with recreational vehicles generally. This is accomplished by securing the lifting portion of acme nut bracket 102 to the desired object to be lifted. Thus, as the acme nut bracket travels along the length of the acme screw 106, the acme nut bracket 102 also travels, moving any object attached to it.
A variety of securing methods may be used to secure the object to the acme nut bracket 102, including rivets, bolts, flanged lips, shelves and even nails. Different securing methods may be desired, depending on the nature of the object to be lifted.
Note that while this embodiment presents a single bracket 102 to both capture the acme nut 110 and secure to the object, multiple brackets may be used for this purpose. For example, an acme nut bracket could be used to capture the acme nut, and a lifting bracket could be used for securing the payload/object to be lifted. The two brackets could then be mounted together to act as a single bracket.
The acme screw 106 may be rotated by a variety of devices such as a manual crank, pull chain, or motor. Although no rotational mechanism is illustrated in
RV Lifting Device With Safety Features
Safety lifting device 200 functions in a similar manner to the previous embodiment shown in
The primary difference of this embodiment lies in the use of a primary acme nut 202 and a secondary acme nut 204. Both acme nuts are “captured” by the acme nut bracket 208 and both acme nuts 202, 204 are threaded onto the elongated acme screw 206. However, the weight that the acme nut bracket 208 carries (from the weight of lifting an object secured to the bracket) falls exclusively on the top surface of the primary acme nut 202. In normal operation, the secondary acme nut 204 carries no weight from the acme nut bracket 208 nor indirectly from the object that is being lifted.
Over time, continued use and excessive weight may cause the primary acme nut 202 to fail. Usually, these failures are due to stripping of the primary acme nut 202 threads. At this point, the embodiment of
As described above, the safety lifting device 200 has a primary acme nut 202 which normally supports all of the weight of the acme nut bracket 208 and indirectly the bracket's payload. If the primary acme nut 202 should fail, the acme nut bracket 208 falls to the secondary acme nut 204. Consequently, both the acme nut bracket 208 and the bracket's payload will sit lower relative to the secondary acme nut 204 then if the primary acme nut 202 had not failed.
Referring once again to
This visual indicator 220 may be located on a back wall, the support bracket 216, or other fixed object. Preferably, the visual indicator 220 will align with a portion of the safety lifting device 200 in a fully elevated or fully lowered position. In this fashion, the safety lifting device 200 is at an absolute position where its height can be compared to the visual indicator 220.
Manual Bed Lifting Device
The safety lifting device 200 of this embodiment functions in much the same way as previous embodiments. Captured acme screws ride up and down the rotatably mounted acme screw 206, moving the attached beds upward or downward, depending on the direction of the acme screw 206 rotation.
The acme screw 206 is mounted at each of its ends to the support bracket 216. At the top end of the acme screw 206 is a chain sprocket 222 securing a chain (not shown). This chain extends along cross bar 234 to a second chain sprocket 222 on the opposite side, then across the crane 226. Each end of the chain terminates at chain opening 228 with a chain handle (not shown) on each end of the chain. This design allows a user to pull either chain handle and thus the chain, which rotates the chain sprocket 222 and consequently the acme screw 206. By pulling one handle, the acme screw 206 will be rotated in one direction, while pulling the other handle rotates the acme screw 206 in the opposite direction.
As previously described, the safety lifting device 200 is composed of a primary acme nut 202 and a secondary acme nut 204, both of which are held from rotation by the acme nut bracket 208. In turn, the acme nut bracket 208 secures bed frame 230.
The acme nut bracket 208 serves as a primary point of attachment to the bed frame 230. In addition to the support of the acme nut bracket 208, guide wires 224 are fixed to each corner of the bed frame 230 on one end and to key holes 218 located on the support bracket 216 on the other. These guide wires 224 provide additional support and a further safety mechanism for the bed lifting device.
Since guide wires 224 have metal key-shaped or hook-shaped ends, they easily fit within any of the key holes 218 in order to adjust to a suitable height. The guide wires 224 may be composed of cables, belts, or similar elongated structures, so long as they provides support to the lift while maintaining enough flexibility to allow the safety lifting system 200 to move upward.
To lift the beds 231, a user merely pulls one of the chain handles located at chain opening 228. This moves the chain in one direction, rotating the acme screws 206, and consequently moving the acme nuts up the acme screws 206. To lower the bed, user simply pulls the other end of the chain from the chain opening 228. This causes the acme screws 206 to rotate in the opposite direction, moving the acme nuts down the acme screws 206.
The embodiment shown in
To lower the beds, the lift device 200 is once again actuated, causing both bunks to lower. Gravity pushes the top bed down along support bracket 216 until it is stopped by the force of guide wires 224. The bottom bed continues to move downward until it reaches the end of acme screw 206.
Although this embodiment illustrates the top bunk without a lift mechanism 200, it should be understood that the top bed may also have a lift mechanism 200 to raise and lower itself.
Motorized Bed Lifting Device
The motor 302 drives the motorized bed lifting device from the top of support bracket 304. The energy of motor 302 is transferred by way of two gear boxes 306 and a cross shaft 308. As seen in
In this manner, when a user actives the motor, each lifting bracket 312 and further each side of bed bracket 310, will raise or lower at the same speed.
The motor 502 transfers power to the acme screw 510 through a drive shaft gear 508 mounted to the drive shaft of motor 502. In turn, acme gear 506 couples to the drive shaft gear 506, allowing it to rotate the acme screw 510.
The acme capture bracket 512, primary acme nut 516, and secondary acme nut 514 function in the same manner as mentioned above. As motor 502 rotates acme screw 510, the captured primary acme nut 516 pushes the acme nut capture bracket 512 upwards or downwards along the screw.
As is apparent, this lower positioning of motor 502 ultimately results in similar functionality as previously mentioned embodiments.
Secondary Safety Support Devices
While the lifting devices above provide increased safety for users, additional safety mechanisms may be used to enhance safety further. Guide wires 224 and support latch 600 provides two such examples of these additional safety mechanisms.
The latch 600 is composed of two main parts: the latch mount 602 and the tongue 608. The latch mount 602 fastens to a fixed location 618 such as an adjacent wall or lift support framework. It's structure consists of a panel having vertical fins extending perpendicularly outward. Both fins have a curved slot 606 and a roll bar 604. The roll bar 604 extends across the latch mount 602, through both curved slots 606. The end of roll bar 604 radially flange outward, allowing the roll bar 604 to remain within the confines of the curved slots 606.
The latch 600 can be mounted at any height desired by the user. Additionally, the latch mount 602 can be adjustably mounted to allow a user to easily modify the vertical height where the latch 600 activates. Further, multiple latch 600 units may be used with a single lift mechanism, providing added support and safety for larger loads.
Manual RV Trailer Jack
The lifting device of the present invention may also be used as a trailer jack.
Generally, this jack embodiment consists of dual lifting devices 401 and 403 adapted to mount on either side of a RV trailer, such as a fifth wheel travel trailer. These lifting devices may be adapted to swing up against the trailer when not in use and have a mechanism for synchronizing each device for evenly lifting the trailer. Although two lifting devices 401 and 403 are presented in this embodiment, it should be understood that a single lifting device may be used for a similar purpose.
Each lifting device 401 and 403 functions in a similar fashion to previous embodiments. Specifically, a dual acme nut lift mechanism serves to raise and lower the device while also providing visual benchmarks for determining acme nut failure.
Again looking at
Like previous embodiments, a primary acme nut 412 and a secondary acme nut 410 are “captured” or held from rotation around the acme screw 408 by the inner leg 420. As best seen in
The acme screw 408 passes through the top of inner leg 420 and terminates at the top of jack leg 422 with a gear box 430 which drives the rotation of the acme screw 408. Thus, the gear box 430 ultimately controls the direction of rotation of the acme screw 408 and further the direction that the dual acme nuts travel along it.
The lifting device 401 provides an additional height adjustment mechanism. A handle actuated pin lock 440 is located on the lower end of inner leg 420. By moving the handle, a user may insert or retract a locking pin from within inner member 420. Conveniently located within the drop leg 418 are a series of pin holes 432, spaced along its length. Since the drop leg 418 telescopically slides within the inner leg 420, the pin holes 432 may be aligned with the locking pin. This arrangement allows a user to operate the handle actuated pin lock 440 to unlock the drop leg 418, adjust it to a new position, and finally relock it. Since these height adjustments are independent of each lifting device 401, they are especially appropriate for compensating for uneven ground when parking a trailer.
In order for the trailer jack to properly lift, both lifting devices 401 and 403 must lift at the same rate. The present embodiment accomplishes this by making one of the lifting devices 401 a leader and the other, 403, a follower. This arrangement is most clearly seen in
The gear box 430 is coupled to two additional components: the acme screw 408 and the cross shaft 438. The purpose of the cross shaft is to rotate in unison with the crank shaft 436 and transfer this rotational energy to the gear box 430 on the follower lifting device 403, which ultimately turns the acme screw 408. In this manner, rotating the hand crank 436 actuates both the leader lifting device 401 and the follower lifting device 403 at the same rate.
In operation, the trailer jack works as follows: A user begins to rotate the hand crank 436 in a desired direction. The rotation of the hand crank 436 motivates the gear box 430 which begins rotating the acme screws in both the leader lifting device 401 and the follower lifting device 403 by way of the cross shaft 438. From this point on, each of the two lifting devices operate in the same manner. The acme screw 408 rotates, causing the captured primary acme nut 412 and captured secondary acme nut 410 to press against circular flange 413. As the acme screw 408 rotates, the force on the primary acme nut 412 moves the acme screw 408 upwards relative to the inner leg 418. By rotating the hand crank 436 in the opposite direction, the process is reversed, and the acme screws 408 move inward relative to the inner leg 418. In this manner, inner leg 418 telescopes into and out of jack leg 422, lifting the RV trailer or other load coupled above it.
As previously described in this application, visual benchmarks may be added to this embodiment to warn a user of primary acme nut failure. Visual indicator 434 is best seen in
With a normal functioning primary acme nut 412, the bottom of jack leg 422 will align with a predetermined indicator line on the visual indicator. When the primary acme nut 412 fails, the circular flange moves the failed nut against the secondary acme nut 410, leaving the secondary acme nut 410 to support all the weight of the RV trailer. In this circumstance, the jack leg 422 sits lower relative to the inner leg 420, especially in the absolute positions of fully extended or fully retracted. Consequently, the bottom edge of the jack leg 420 aligns to a lower marker level on the visual indicator 434.
Although the invention has been described in terms of particular embodiments and applications, one of ordinary skill in the art, in light of this teaching, can generate additional embodiments and modifications without departing from the spirit of or exceeding the scope of the claimed invention. Accordingly, it is to be understood that the drawings and descriptions herein are proffered by way of example to facilitate comprehension of the invention and should not be construed to limit the scope thereof.
|Citing Patent||Filing date||Publication date||Applicant||Title|
|US7744142||Jun 9, 2008||Jun 29, 2010||Lippert Components, Inc.||Strap bed lift|
|DE102010015843A1||Mar 5, 2010||Nov 18, 2010||Frankia Pilote Gmbh & Co. Kg||Seat furniture i.e. corner seat, for use in recreational vehicle, has backrest part separated from seat part and arranged in raised and lowered positions, and guide and lifting mechanism provided for height adjustment of backrest part|
|DE202009003170U1||Mar 10, 2009||Jul 15, 2010||Frankia Pilote Gmbh & Co. Kg||Sitzm÷bel|
|DE202010018217U1||Mar 5, 2010||Oct 10, 2014||Frankia-Gp Gmbh||Sitzm÷bel|
|International Classification||B66F3/08, B60P3/39, B60P3/34, B60S9/08|
|Cooperative Classification||B60P3/39, B60S9/08, B66F3/08|
|European Classification||B66F3/08, B60P3/39, B60S9/08|
|Jun 4, 2008||AS||Assignment|
Owner name: AL-KO KOBER CORPORATION, INDIANA
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:RBW, INDUSTRIES, INC.;REEL/FRAME:021040/0746
Effective date: 20080430