Patent Publication Number: US-2005129494-A1

Title: Adjustable forklift adapter and method

Description:
BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The present invention relates to forklifts. In particular, the present invention relates to an adapter to convert, and a method to adapt, a wide variety of existing earth moving and farming implements and attachments, hereinafter “hydraulic implements,” to lift paletted loads and other cargo.  
      2. Description of the Related Art  
      There have been a number of attempts at providing forklift adapters to existing hydraulic equipment, with varying degrees of success.  
      U.S. patent application Publication 2003/0068217, published Apr. 10, 2003, shows a fork attachment for a backhoe but requires either removal of the bucket from the backhoe arm, or the modification thereof with adapter plates.  
      U.S. Pat. No. 6,524,054, issued on Feb. 25, 2003 to F. Maney, discloses a forklift apparatus having a tongue which is matable to the square tow hitch receiver mounted to the rear end of an automobile or light truck. The forklift apparatus described by Maney includes a pair of tines laterally and adjustably fixed to a crossbar member that is connected to a jack. The tines are not attachable to different types of hydraulic implements such as loaders, buckets or blades.  
      U.S. Pat. No. 6,547,508 issued Apr. 15, 2003 and U.S. Pat. No. 6,287,070 issued Sep. 11, 2001 to J. A. Perry, disclose a load bearing attachment for a multipurpose loader bucket. This device latches onto the lower horizontally extending lip of the bucket and is not adaptable or configurable for use with different types of hydraulic implements.  
      U.S. Pat. No. 6,287,073, issued Sep. 11, 2001 and U.S. Pat. No. 6,533,526, issued Mar. 18, 2003 to G. Lindgren et al., disclose a detachable forklift frame having a pair of laterally adjustable load-carrying forks or tines. The tines are supported by a rack fixed to the frame, but are not adjustable for use with various other hydraulic implements.  
      U.S. Pat. No. 3,876,090, issued Apr. 8, 1975 to J. D. Holland, and U.S. Pat. No. 6,065,926 issued May 23, 2000 to D. G. Knapp, show a forklift configured for attachment to a farm tractor&#39;s three-point hitch. Use of these devices requires that whatever implement currently attached to the tractor be removed prior to attaching the forklift attachment. With regard to the Knapp device, the tines are laterally adjustable by sliding along a support beam. However, they are not adjustable in other directions nor are they suitable for use with an existing hydraulic implement.  
      U.S. Pat. No. 4,421,449, issued Dec. 20, 1983 to V. Cotton, and U.S. Pat. No. 5,582,502, issued Dec. 10, 1996 to L. L. Herin, show forklift attachments designed to be mounted to a snowblade lift. As with other prior art devices, however, the snowblade must first be removed prior to attaching the forklift attachment. With regard to the Cotton device, the tines are slidably mounted to a cross-frame member. However, they are not adjustable, nor are they suitable for use with an existing hydraulic implement.  
      As can be seen, the prior art forklift adapters are variously heavy, unwieldy, expensive, and complex. None are easily carried or stored when not in use and none are adequately adaptable for use with a variety of existing hydraulic implements.  
      None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed. Thus, an adjustable forklift adapter solving the aforementioned problems is desired.  
     SUMMARY OF THE INVENTION  
      The forklift adapter of the present invention includes a tine portion extending generally horizontally forwardly from a proximal end, a leg portion extending generally vertically along a vertical axis from the said proximal end of the tine portion, and a top portion extending generally rearward from near the top of the leg potion. The leg portion includes an upper leg member and a lower leg member which are slidingly engaged to one another such that the leg portion is extensible. Also provided is a means for locking the upper leg member to the lower leg member into a selected fixed position with respect to one another. A hydraulic implement may therefore be adapted to lift paletted and other loads by hanging two such forklift adapters over the implement.  
      Accordingly, it is a principal object of the invention to provide an adapter to enable existing hydraulic implements to be used for lifting paletted loads without modifying existing equipment or removing any attachments or implements.  
      It is another object of the invention to provide an adapter that allows existing equipment to be used for lifting paletted loads that is easy to install and remove.  
      It is a further object of the invention to provide such an adapter that is easy to carry by a single person from place to place and to store.  
      It is an object of the invention to provide improved elements and arrangements thereof for the purposes described which is inexpensive, dependable and fully effective in accomplishing its intended purposes.  
      These and other objects of the present invention will become readily apparent upon further review of the following specification and drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a perspective view of an exemplary adjustable forklift adapter according to the present invention.  
       FIG. 2  is a section view taken along lines  2 - 2  of  FIG. 1 .  
       FIG. 2A  is a detail cross-section view of the adjustable forklift adapter of  FIG. 2 , where the cross section is taken along line  2 A- 2 A.  
       FIG. 3  shows a loader implement fitted with two of the adjustable forklift adapters shown in  FIGS. 1 and 2 .  
       FIG. 4  shows a pair of the adjustable forklift adapter of  FIGS. 1 and 2  used with a box blade. 
    
    
      Similar reference characters denote corresponding features consistently throughout the attached drawings.  
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
      Referring to  FIG. 1 , an adjustable forklift adapter is shown generally at  10 . Forklift adapter  10  includes a tine  12  extending horizontally and useful for lifting loads such as are commonly placed on a pallet or skid. Tine  12  is fixed to lower leg member  14 , which extends substantially vertically from the proximal end of tine  12 . Side braces  13  strengthen the connection between tine  12  and lower leg member  14 . Lower leg member  14  slidingly engages upper leg member  16 . As shown in  FIG. 2 , lower leg member is a solid post slidingly engaged with upper leg member  16 , which is formed from rectangular steel tubing.  
      A spring-loaded pop pin  18  locks lower leg member  14  to upper leg member  16 . Spring-loaded pop pins are known to the field of exercise equipment. Referring now to  FIG. 2A , spring-loaded pop pins generally include a cylindrical housing  31  containing an internal pin  35  biased to extend out of housing  31  in a first direction (into blind hole  17 ) by compression spring  37 . Handle  33 , which is fixed to internal pin  35 , extends out of housing  31  opposite the first direction so that internal pin  35  can be retracted into housing  31  by pulling on handle  33 . Spring-loaded pop pins of the type contemplated for the present adjustable forklift adapter are available from Innovative Components, Inc. in Schaumburg, Ill., USA. Additional details of the construction of the spring-loaded pop pin can be obtained from U.S. Pat. No. 4,239,412, issued Dec. 16, 1980 to Hogan, which is hereby incorporated by reference.  
      In a preferred construction, spring-loaded pop pin  18  is welded to an opening  15  in upper leg member  16  to allow internal pin  35  to extend into blind holes  17  drilled into lower leg member  14 . While only three blind holes  17  are shown in  FIGS. 1, 2 , and  2 A, any number of holes may be provided, each preferably about one inch to one and one-half inch (2.5-3.8 cm) deep and at about one-inch (2.5 cm) intervals along a length of lower leg member  14 . When adjustment is desired, the user pulls handle  33  extending out of spring-loaded pop pin  18  to retract internal pin  35  from one of holes  17 , thereby releasing the connection between upper and lower leg members  16 ,  14  and allowing lower leg member  14  to freely extend from or retract into upper leg member  16 . When a desired amount of extension is reached, the user releases spring-loaded pop pin  18  and when a hole  17  is aligned therewith, the internal pin will automatically engage under the influence of internal compression spring  37 .  
      Upper leg member  16  is fixed at or near its upper end to first top member  20 , which slidingly engages second top member  22 . Spring-loaded pop pin  24  locks first top member  20  with second top member  22  in the same manner that spring-loaded pop pin  18  locks upper and lower leg members  16 ,  14 , as described above with reference to  FIG. 2A . Second top member  22  includes a downwardly extending rear portion  26 .  
      Referring back to  FIGS. 1, 2 , T-handle bolt  28 , shown in  FIG. 2 , is provided to engage or clamp onto the lip of whatever implement or attachment forklift adapter  10  is used with. T-handle bolt is threaded to nuts  29  welded to rear portion  26 . It is also contemplated that rear portion  26  may include directly threaded holes or a threaded bushing.  
      While lower leg member  14  and upper leg member  16  are slidingly engaged by a post-in-tube configuration, this is not the only method contemplated of slidingly engaging the two leg members together. For example, the members may be formed of channel-in-channel, nested angle iron with pin-in-slot cooperating elements, or other cooperating shapes. Preferably, the members are formed by a solid rectangular post extensible within a rectangular tube having outside dimensions of about 2 inches (5 cm) by 4 inches (10 cm).  
      Extensible rear brace  34  is slidingly engaged to tine  12  and extends rearward of tine  12  in case additional bracing is-required. Spring-loaded pop pin  36 , positioned at one of side braces  13 , locks rear brace  34  in any desirable position. Rear brace  34  is useful in situations where tines  12  would otherwise point down. For example, if a forward-sloping dirt or snow blade is used, rear brace  34  may be extended to push against the vertical back part of the blade to maintain tine  12  in a horizontal position. In other cases, a bucket, loader, or other similar implement may lack a vertical support to prevent tine  12  from slanting down. The advantages of rear brace  34  in these circumstances will be further described below with reference to  FIG. 3 .  
      Preferably, locking means locking upper leg member  16  to lower leg member  14 , first upper portion  20  to second upper portion  22 , and tine  12  to rear brace  34  is provided by spring-loaded pop pins  18 , and  24 , and  36 , as shown and described above with respect to  FIG. 2A . However, other locking means are contemplated. For example, a pin may extend through both members and retained using a cotter- or hair-pin (not shown) extending through the pin&#39;s terminus. Or a threaded bolt and nut combination may be used to lock two members together. Alternatively, instead of a device for locking at discrete positions, a self-locking jackscrew or other continuously adjustable mechanism may be used to adjust the length of leg members  14 ,  16  and other slidingly engaged parts.  
      Furthermore, while the leg portion is shown as comprising lower leg  14  and upper leg  16  only, it is also possible to include a third intermediate leg portion (not shown) to provide increased extension capability. The same holds true for the top portion.  
      Tine  12  preferably has a length of about 3.5 feet (1 m). Upper leg  16  and lower leg  14  preferably have a combined length when collapsed of about 18 inches (46 cm). First and second top members preferably have a combined length when collapsed of about 6 inches (15 cm). Rear portion  26  has a preferred length of about 4 to 6 inches (10-15 cm) from the top of adapter  10 . These dimensions are considered to be the most desirable so that forklift adapter  10  can cooperate with the largest number of existing implements and attachments. However, many other possible dimensions are possible without departing from the spirit and scope of the invention. For example, the vertically extending leg members, the top members, and/or rear member may be elongated with respect to other portions of the adapter, or the entire adapter may be scaled up or down to suit various needs.  
      Referring now to  FIG. 3 , a pair of forklift adapters  10  are shown hooked onto a typical loader implement  40  of, for example, a bulldozer (not shown). Note that adapters  10  may be adjusted so that tines  10  are positioned even with the bottom edge of dirt blade  40 . Top members hook over the top of dirt blade  30  while rear braces  34  are used to provide additional stability to adapters  10  by bracing against the inside wall of loader blade  40 . Adapters  10  may be laterally adjusted by sliding them left or right along the width of dirt blade  40 . This might be necessary for example, in moving large objects such as garbage dumpsters. If desired, more than two forklift adapters may be used to, if needed, stably lift heavier or wider loads, such as a shed or other portable structure.  
      Referring to  FIG. 4 , two forklift adapters  10  are shown hooked on the outer side of a box blade  42  of loading/grading equipment (not shown).  
      It is to be understood that the present invention is not limited to the embodiment described above, but encompasses any and all embodiments within the scope of the following claims.