(Not Applicable)
The present invention relates to a personnel lift and, more particularly, to a portable lift machine including a work platform raised and lowered by a lifting system. The LiftPod® system by JLG Industries, Inc. has been described in U.S. patent application Ser. Nos. 10/594,666, 11/581,785, 12/190,217, 12/293,759, U.S. Pat. Nos. D570,071, 7,614,459, 7,762,532, and 7,766,750. See also www.LiftPod.com. The contents of the referenced documents and website are incorporated by reference.
The ladder concept is several thousand years old. Existing ladders, however, can be cumbersome and difficult to maneuver. Additionally, conventional ladders can be unstable particularly on uneven ground, and a work area is limited to the user's reach.
Ladder companies are reluctant to develop powered mechanical products. It would be desirable, however, to develop a personnel lift that achieves many of the advantages of a ladder, e.g., can be set up and used by a single operator, lightweight, etc., while providing for greater stability and a larger working area in a portable powered machine
Mast climbing platforms are known and typically include a mast that can be free-standing or supported by a wall or other support structure. However, existing mast climbers have minimum SWL loads of 1000 lbs and are not portable or operable by a single user due at least to their size. Vertical mast products and aerial work platforms include a moving platform and generally are also typically too large for portability and are very far from the many advantages provided by a ladder in terms of portability, low cost and ease of use.
To achieve portability, a light weight, reliable lift system mechanism is desirable to provide the functionality expected of a device which lifts personnel.
A desirable feature of the LiftPod system is its low weight and portability. A single operator can assemble the unit. The portable construction enables the single operator to carry it up stairs, load the unit in a truck bed, etc. The system incorporates a full platform with rails around the operator for security. Lift power can be provided via a cordless drill or a dedicated power pack.
The invention embodies a personnel lift system that is smaller in construction than the original LiftPod® system. The invention can serve as an alternative to step ladders (up to 1.8 m/6 ft.) and can incorporate extensions to achieve higher reach.
Gas struts may be provided to store energy in the lowered position and thereby reduce power requirements for the lift. The gas strut in combination with a screw thread (such as an acme screw) and cordless DC motor/battery can provide both the means to power and control the machine to lift and lower a person in the platform in a secure manner.
In an exemplary embodiment, a mast lift includes a base and a telescoping mast coupled with the base and extending upward from the base. The telescoping mast has a support section fixed to the base and a movable section movably connected to and displaceable relative to the support section between a retracted position and an extended position. A top cap is secured to the movable section, and a platform is supported by the top cap and the movable section. A gas strut acts between the support section and the movable section and biases the movable section toward the extended position. A threaded driving rod is connected between the top cap and the base and extends through a fixed nut assembly.
The gas strut may be secured to the base. The mast lift may additionally include a drive link coupled with the threaded driving rod that receives a rotary power source to rotate the threaded driving rod. The drive link may comprise a socket for receiving a complementary bit of a hand-held power drill. The fixed nut assembly may include a housing secured to the gas strut and a nut disposed in the housing, where the threaded driving rod may be threaded through the nut. The telescoping mast may additionally include a middle section cooperable with the support section and the movable section. In this context, the mast lift may further include a second gas strut and a second threaded driving rod that are configured to displace the middle section relative to the support section.
In another exemplary embodiment, a mast lift includes a base and a telescoping mast coupled with the base and extending upward from the base. The telescoping mast includes a support section fixed to the base, a middle section displaceable relative to the support section, and a top section displaceable relative to the support section and the middle section. A top cap is secured to the top section, and a platform supported by the top cap and the top section. A gear box is secured to the middle section. A first gas strut is secured at one end to the middle section and acts between the middle section and the top section and biases the top section toward an extended position. A first threaded driving rod is connected between the top cap and the middle section and extends through a first fixed nut assembly. A second gas strut may be secured between the gear box and the support section, and a second threaded driving rod may be connected between the gear box and the base and extending through a second fixed nut assembly. The second threaded driving rod may be fixed to the second gas strut. The gear box may include a power transfer belt connected between the first threaded driving rod and the second threaded driving rod, where the first threaded driving rod is configured such that when the first threaded driving rod reaches a maximum extended position, the rotary power is transferred to the second threaded driving rod by the power transfer belt.
In yet another exemplary embodiment, a multi-section mast lift includes a base; a telescoping mast supported on the base, the telescoping mast including a support section secured to the base, at least one middle section cooperable with the support section and displaceable relative to the support section between a retracted position and an extended position, and a top section cooperable with a topmost one of the at least one middle section and displaceable relative to the topmost one of the least one middle section between a retracted position and an extended position; a top cap secured to the top section; a platform supported by the top cap and the top section; a gear box secured to the at least one middle section; and a lifting assembly for displacing the top section and the at least one middle section between the retracted and extended positions, the lifting assembly including a threaded driving rod and a gas strut for each of the top section and the at least one middle section, wherein the threaded driving rods are driven by rotating a single drive link cooperable with the lifting assembly.
These and other aspects of the invention will be described in detail with reference to the accompanying drawings, in which:
With reference to
The telescoping mast 14 is provided with a support section 18 fixed to the base 12 and a movable section 20 movably connected to and displaceable relative to the support section 18 between a retracted position (lowered position shown in
With reference to
Those of ordinary skill in the art will appreciate alternative configurations for the drive construction, and the invention is not necessarily meant to be limited to the described and illustrated examples. For example, an alternative configuration could fix the threaded rod rotationally and drive the nut/threaded hole. In this context, the thread can be fixed to the lower section of the mast, whilst the nut is rotated and drives the machine up. The thread could similarly be fixed to the top section whilst driving the nut. To drive the nut, it may simply be a hollow tube with the drive shaft connected on top for matching to the drill/power pack.
A gas strut 28 acts between the support section 18 and the movable section 20 and is configured to bias the movable section 20 toward the extended position (platform raised position—
With reference to
With reference to
As shown in
In use, with the mast lift 10 in a lowered position (
The mast lift 10 is easily transported by a single user. For additional portability, the wheels 44 can be removed and placed onto the platform as shown in
The maximum reach of the lift can be extended through the use of a longer support section 18 and movable section 20. Alternatively or additionally, the mast 14 may include one or more additional sections cooperable with the support section 18 and movable section 20. For example, see
In the exemplary three-section lift, the lift mechanism includes a first threaded driving rod 26-1 acting between an outer section 54 and a middle section 56 and a second threaded driving rod 26-2 acting between the middle section 56 and the support (inner) section 58. The assembly also includes a first gas strut 28-1 cooperating with the first threaded driving rod 26-1 and a second gas strut 28-2 cooperating with the second threaded driving rod 26-2. Cylinders 29 house the driving rods when the mast is in a retracted position. The cylinders 29 keep the rods from hitting other objects within the mast when retracting, and they also house grease to keep the rods lubricated.
A top cap 60 is secured, e.g., bolted, to the outer section 54 and supports the platform 16 and operator. A gear box 62 is secured to the middle section 56 via a bolted connection or the like. The first threaded driving rod 26-1 is fixed or anchored to the middle section 56 within the gearbox 62. A guide tube 63 surrounds the first threaded driving rod 26-1 and is supported via a guide 64 (clearance fit). The first threaded driving rod 26-1 extends through a corresponding first fixed nut assembly 66. The nut assembly 66 preferably includes a nut housing 67, a primary nut 68 and a safety nut 70. As the first threaded driving rod 26-1 is rotated in the fixed nut 68, the threaded driving rod 26-1 is displaced relative to the nut 68 (depending on the direction of rotation). The safety nut 70 acts as a back-up in the event that the primary nut 68 fails.
A drive link 72 receives a rotary power source such as a hand-held power drill or the like to rotate the threaded driving rod 26-1 through a set of gears 73. In a preferred arrangement, the drive link 72 is a socket for receiving a complementary bit of the hand-held power drill.
The first gas strut 28-1 is anchored to the middle section 56 via a suitable connector 74 (see
With reference to
The second threaded driving rod 26-2 is connected between the gear box 62 and the support section 58. A guide tube 79 surrounds the second threaded driving rod 26-2. As noted, the support section 58 is secured with the base, and the second threaded driving rod 26-2 is effectively anchored to the base through the support section 58. That is, the load is transferred from the second threaded driving rod 26-2 to the second fixed nut assembly 78, from the second fixed nut assembly 78 to the support section 58 via a bolted connection 80 (see
In use, in a preferred embodiment, when the outer section 54 is extended, the first threaded driving rod 26-1 and the first gas strut 28-1 act in concert in an upward direction on the top cap 60. As noted, the top cap 60 is bolted to the outer section 54, which supports the platform 16 (and the operator). An opposing force is supported by the gear box 62 and is transferred to the middle section 56 via suitable connections (e.g., bolted connections). The middle section 56 thus acts as a support section as the outer section 54 is being extended.
After the outer section 54 has been raised/extended to a maximum position or when the friction between the first threaded driving rod 26-1 and the primary nut 68 exceeds the corresponding friction at the second threaded driving rod 26-2, the rotary power by the drive link 72 is transferred to the second threaded driving rod 26-2 by the power transfer belt 76. The second gas strut 28-2 and the second threaded driving rod 26-2 act on the gear box housing 62 to extend/elevate the middle section 56. The reaction forces are placed on the support section 58 and then are transferred to the ground via the machine base. At this point, the middle section 56 is the extending section and the support section 58 provides support for the lifting components acting on the middle section 56.
In use, after entering the platform 16, an operator engages the threaded driving rod 126 with a hand-held power drill. As the rod is rotated, the moving rod 106 is displaced linearly relative to the base rod 104, which causes the double linkage parallelogram assembly 102 to extend from the position shown in
The lightweight construction of the described embodiments provides the functionality of a ladder with added advantages. An operator can maintain two hands for working, with space for supporting tools and materials. The powered lift facilitates operator use and increases operator comfort. The platform provides added safety and maintains the operator center of gravity well inside a tipping line. This structure avoids typical set up and climb up risks of scaffolding.
While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiments, it is to be understood that the invention is not to be limited to the disclosed embodiments, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.
This application is a continuation-in-part (CIP) of U.S. patent application Ser. No. 13/191,676, filed Jul. 27, 2011, pending, which claims the benefit of U.S. Provisional Patent Application No. 61/374,368, filed Aug. 17, 2010, the entire contents of each of which are hereby incorporated by reference in this application.
Number | Name | Date | Kind |
---|---|---|---|
1342828 | Seymour | Dec 1915 | A |
2676677 | Anderson et al. | Apr 1954 | A |
2762659 | Harlan et al. | Sep 1956 | A |
2948363 | Hopfeld | Aug 1960 | A |
3404752 | Deines | Oct 1968 | A |
3871478 | Bushnell, Jr. | Mar 1975 | A |
3876039 | Bushnell, Jr. | Apr 1975 | A |
RE28455 | Denier | Jul 1975 | E |
4258825 | Collins | Mar 1981 | A |
4427093 | Wehmeyer et al. | Jan 1984 | A |
4427094 | Winkelblech | Jan 1984 | A |
4458786 | Lebre | Jul 1984 | A |
4575976 | McDermott | Mar 1986 | A |
4592447 | Ream et al. | Jun 1986 | A |
4752102 | Rasmussen | Jun 1988 | A |
4875555 | Johansson et al. | Oct 1989 | A |
4987976 | Daugherty | Jan 1991 | A |
5044473 | Gripe | Sep 1991 | A |
5111907 | Kishi | May 1992 | A |
5143181 | Bixby | Sep 1992 | A |
5203425 | Wehmeyer | Apr 1993 | A |
5273132 | Sasaki et al. | Dec 1993 | A |
5425433 | Huber | Jun 1995 | A |
5427197 | Waters | Jun 1995 | A |
5624046 | Zimmermann | Apr 1997 | A |
5636705 | St. Germain | Jun 1997 | A |
5755306 | Kraemer et al. | May 1998 | A |
5803204 | White et al. | Sep 1998 | A |
5850892 | Citron et al. | Dec 1998 | A |
5890559 | Busuttil et al. | Apr 1999 | A |
6041491 | Ishikawa et al. | Mar 2000 | A |
6174124 | Haverfield et al. | Jan 2001 | B1 |
6206059 | Maakad et al. | Mar 2001 | B1 |
6299336 | Hulse | Oct 2001 | B1 |
6401864 | Stringer et al. | Jun 2002 | B1 |
6471004 | Stringer et al. | Oct 2002 | B2 |
D570071 | Campbell et al. | May 2008 | S |
7497140 | Blackwelder et al. | Mar 2009 | B2 |
7614459 | Campbell et al. | Nov 2009 | B2 |
7762532 | Campbell et al. | Jul 2010 | B2 |
7766750 | Campbell et al. | Aug 2010 | B2 |
7896366 | Campbell et al. | Mar 2011 | B2 |
8292039 | Campbell | Oct 2012 | B2 |
20070125599 | Campbell et al. | Jun 2007 | A1 |
20080314690 | Campbell et al. | Dec 2008 | A1 |
Number | Date | Country |
---|---|---|
85 05 465 | Apr 1985 | DE |
0 096 208 | Dec 1983 | EP |
0 273 888 | Jul 1988 | EP |
57-46577 | Sep 1955 | JP |
49-104354 | Oct 1974 | JP |
63-168160 | Jul 1988 | JP |
2-4900 | Jan 1990 | JP |
2-159404 | Jun 1990 | JP |
2-107337 | Aug 1990 | JP |
3-100289 | Oct 1991 | JP |
4-366050 | Dec 1992 | JP |
5-69079 | Sep 1993 | JP |
6-340398 | Dec 1994 | JP |
9-151088 | Jun 1997 | JP |
10-36087 | Feb 1998 | JP |
2000-153995 | Jun 2000 | JP |
3166610 | Mar 2001 | JP |
2003-327393 | Nov 2003 | JP |
2006-264797 | Oct 2006 | JP |
2007-39227 | Feb 2007 | JP |
Entry |
---|
European Examination Report dated Jul. 20, 2015 issued in European Patent Application No. 11177697.7, 5 pp. |
Japanese Office Action dated Jan. 6, 2015 issued in Japanese Patent Application No. 2013-524956 and English translation, 7 pp. |
Japanese Office Action dated Feb. 14, 2013 issued in Japanese Patent Application No. 2011-178048 and English translation, 6 pp. |
Japanese Office Action dated Dec. 3, 2013 issued in Japanese Patent Application No. 2011-178048 and English Translation, 4 pp. |
Japanese Office Action mailed Feb. 25, 2014 issued in Japanese Patent Application No. 2013-524956 and English Translation, 10 pp. |
Number | Date | Country | |
---|---|---|---|
20140332317 A1 | Nov 2014 | US |
Number | Date | Country | |
---|---|---|---|
61374368 | Aug 2010 | US |
Number | Date | Country | |
---|---|---|---|
Parent | 13191676 | Jul 2011 | US |
Child | 14338906 | US |