Post puller

Information

  • Patent Grant
  • 6398188
  • Patent Number
    6,398,188
  • Date Filed
    Thursday, November 30, 2000
    24 years ago
  • Date Issued
    Tuesday, June 4, 2002
    22 years ago
  • Inventors
  • Examiners
    • Watson; Robert C.
    Agents
    • Litman; Richard C.
Abstract
The post puller has an H-shaped base including a pair of parallel legs and a crossbeam normal to the legs, the crossbeam being offset from the midpoint of the legs and defining a shallow channel and a deep channel. A pair of rectangular blocks attached to the legs and crossbeam in the deep channel provide platforms on which a pair of single action hydraulic cylinders are mounted, and define a recess which straddles the post to be pulled. A cross member is pivotally mounted to each cylinder rod. A chain is suspended from the midpoint of the cross member. The chain may be wrapped directly around the post, or a post gripping structure may be attached to the free end of the chain. A pair of wheels may be mounted to the base for portability.
Description




BACKGROUND OF THE INVENTION




1. Field of the Invention




The present invention relates to a post puller for pulling a post or a post anchor from the ground.




2. Description of the Related Art




Several devices are supported by one or more posts driven into the ground. Such devices include signs, mail boxes, fences, and the like. The post may be a one-piece post with the load carrying portion driven directly into the ground, or a two piece post with a post anchor driven into the ground, and the upper or load carrying portion of the post being driven or bolted to the post anchor. For purposes of the present application, the term “post” will be used to refer to either the one-piece or two piece assembly, and to either a post or post anchor. From time to time it may become necessary to remove or relocate the post. It then becomes necessary to remove the post and/or the post anchor.




It is sometimes possible to remove the post manually. This process is labor intensive, and may require striking the post from several different directions with a sledge hammer to loosen the ground about the post, and then leaning over and grabbing the post and yanking the post out of the ground. Not only is the process labor intensive, but the post may become damaged so that it cannot be reused, and the laborer can sustain a back injury in the process.




In order to obviate these problems, several machines or mechanical devices have been developed. U.S. Design Pat. No. 372,177, issued Jul. 30, 1996 to S.C. Hansen, shows a mechanical post puller with a single support post having a roller offset from the top of the post and what appears to be a ratchet mechanism with a C-shaped arm for gripping a post at the bottom of the support post.




Several devices are adapted for use with a tractor, front end loader, or other vehicle with a hydraulic system. U.S. Pat. No. 3,526,387, issued Sep. 1, 1970 to H. B. Fleming, describes a post puller having a metal plate base with a flared opening for straddling a post, a pair of uprights pivotally mounted on opposites side of the flared opening, a single hydraulic cylinder, pivotally mounted to the base and connected to a vehicle hydraulic system, a lever arm connected between the cylinder ram and the two uprights, and a chain with a post gripping fixture depending from the lever arm. U.S. Pat. No. 4,244,560, issued Jan. 13, 1981 to W. H. Hawkins, discloses a tree puller attached to a front end loader with a bifurcated wedging member for cutting into a tree trunk, a pair of parallel ground engaging members, each having a hydraulic cylinder mounted thereon with the cylinder rods being attached to an elevatable frame, the wedging member also be attached to the elevatable frame, so that the wedging member cuts into a tree trunk and the cylinder rods are extended to lift the tree out of the ground. U.S. Pat. No. 4,706,935, issued Nov. 17, 1987 to G. L. Thompson, teaches a post puller attached to a tractor three-point hitch, the puller including a stationary gripping plate and a pivotally mounted arcuate gripper, both grippers having teeth for clamping and gripping a post or tree therebetween.




Still other patents are primary concerned with the problem of post slippage in the post puller, several such patents dealing with T-shaped fence posts. U.S. Pat. No. 4,422,621, issued Dec. 27, 1983 to P. B. Ekern, shows a puller for pulling ranch fence posts having lugs extending from the flange of a T-shaped post, the puller having a pair of plated connected by a cross member, the plates having a slot defined therein for receiving a pin which lodges against a fence post lug. A chain is attached to the plates and the post is pulled by a hydraulic cylinder or jack. U.S. Pat. No. 5,011,117, issued Apr. 30, 1991 to Youngblood et al., describes a post puller having a plate with a hole in it so that the plate fits around the post. A chain pulls one side of the plate so that the plate tilts and grips the side of the post to pull it out.




U.S. Pat. No. 5,368,277, issued Nov. 29, 1994 to F. Moss, discloses a device for pulling a T-shaped fence post having bracket and a clevis which fits over the post and is pivotally attached to the bracket. A ring is placed through the bracket and a chain is looped through the ring. A lever is placed through the chain and braced against the ground to pull the post.




A more remote device having some features in common with the present invention is an apparatus for driving a pipe or other: elongated member horizontally through the ground, as described in U.S. Pat. No. 4,746,096, issued May 24, 1988 to Donnell et al. The apparatus uses a rectangular frame with a pair of parallel hydraulic cylinders having rods attached to a tray by a cradle bar. The tray has a plurality of pairs of spaced apart gussets which support a moveable end plate which is placed at an end of a pipe to be driven horizontally into the ground, the pipe being disposed between the hydraulic cylinders. The cylinders are extended to move the tray and pull the end plate against the pipe for the stroke distance of the rods, the end plate is moved forward in the tray, and the process is repeated to drive the pipe into the ground in stages. Optionally, jaws may be attached to the tray for gripping the pipe below collars placed on the pipe to pull the pipe out as the cylinder rods retract.




Another device for a dissimilar purpose but having some features in common with the present invention is a device for lifting the foundation of dwellings, buildings and other structures, described in U.S. Pat. No. 5,492,437, issued Feb. 20, 1996 to L. P. Ortiz. The device has a pier guide tube attached to a support plate which fits under a foundation footing and has two parallel hydraulic cylinders pivotally attached to the guide tube. The cylinder rams are pivotally attached to an articulating bar having a pier compression means between the two rams. A pier is placed into the guide tube and connected to the compression means. One or more piers are driven into the ground until they reach bedrock, after which further retraction of the rams raises the structure. The pier is then permanently affixed to the foundation and the hydraulic cylinders are detached.




There are several problems associated with the post pullers known in the art. Several of the devices are expensive or heavy devices which require attachment to a vehicle for operation. Many manual pullers require that the operator complete the operation in a bent position to extract the post, resulting in back strain and related back injuries. Many puller devices apply a load from the side of the post or utilize a pulling force with a large lateral component relative to the axis of the post, making the post difficult to extract. Consequently there is a need for a lightweight, portable, relatively inexpensive post puller which applies a pulling force primarily along the axis of the post.




None of the above inventions and patents, taken either singularly or in combination, is seen to describe the instant invention as claimed. Thus a post puller solving the aforementioned problems is desired.




SUMMARY OF THE INVENTION




The post puller has an H-shaped base including a pair of parallel legs and a crossbeam normal to the legs, the crossbeam being offset from the midpoint of the legs and defining a shallow channel and a deep channel. A pair of rectangular blocks attached to the legs and crossbeam in the deep channel provide platforms on which a pair of single action hydraulic cylinders are mounted, and define a recess which straddles the post to be pulled. A cross member is pivotally mounted to each cylinder rod. A chain is suspended from the midpoint of the cross member. The chain may be wrapped directly around the post, or a post gripping structure may be attached to the free end of the chain. A pair of wheels may be mounted to the base for portability.




The base assembly is preferably made from aluminum. The entire post puller assembly is lightweight, permitting the post puller to be easily transported on the optional wheels by hand, without the need for a vehicle to transport the puller. The post puller is a self-contained unit, and does not require attachment to a vehicle hydraulic system. In use, each cylinder may be raised individually to rock the post enough to loosen the ground surrounding the post, and then the cylinders may be raised simultaneously to pull the post straight up from the ground. Therefore the unit is more efficient, directing the pulling force along the axis of the post during final extraction of the post.




Accordingly, it is a principal object of the invention to provide a portable post puller for pulling sign posts, mail box posts, fence posts, and the like.




It is another object of the invention to provide a post puller capable of exerting a pulling force directly on the axis of the post.




It is a further object of the invention to provide a post puller with a pair of hydraulic cylinders which may be operated, independently in order to pull a post vertically even on sloping ground.




Still another object of the invention is to provide a post puller with a cross member which may pivot on either side of the post in order to loosen the post before pulling the post vertically from the ground.




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 an environmental, perspective view of a post puller according to the present invention.





FIG. 2

is a front view of a post puller according to the present invention.





FIG. 3

is a plan view of a post puller according to the: present invention.





FIG. 4

is a side view of a post puller according to the present invention.





FIG. 5

is an environmental view of a post puller according to the present invention removing a post from sloping ground, the wheels being omitted.




Similar reference characters denote corresponding features consistently throughout the attached drawings.











DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS




The present invention is a post puller, referenced generally as


10


in the drawings, for pulling posts and post anchors from the ground. As shown in

FIG. 1

, the post puller


10


is transported to the post site, the base


20


is seated on the ground A with the legs


22


of the base


20


straddling the post B, the hoist chain


40


is suspended directly above the post B, the free end of the chain


40


is attached to the post B, and the post B is pulled from the ground by operation of a pair of hydraulic cylinders


60


.




As shown in

FIGS. 1-4

, the post puller


10


has a base


20


which includes a pair of parallel legs


22


joined by a crossbeam


24


normal to the legs


22


defining a generally H-shaped base


20


. As seen most clearly in

FIG. 3

, the crossbeam


24


does not bisect the legs, but is offset towards the rear of the base


20


to define a deep channel


26


at the front of the base


20


and a shallow channel


28


at the rears of the base


20


. A pair of flat, box shaped platforms


30


are attached to the base


20


at the junction of the legs


22


and the crossbeam


24


on opposite sides of the deep channel


26


and define a recess


32


. The legs


22


and crossbeam


24


may be made from square tubing which is joined by welding, but in a preferred embodiment is made in one piece by casting, forging, molding, or by other metal forming processes. In a preferred embodiment, the base


20


is made from a lightweight aluminum alloy, such as 356-T6.




The puller


10


has a pair of single action hydraulic cylinders


60


mounted on the platforms


30


so that the two cylinders


60


are disposed on opposite sides of the recess


32


. Each cylinder


60


has a base


62


which is fixedly attached to a platform


30


so that the, cylinder


60


does not pivot about its mounting point, an extensible rod


64


A and


64


B, respectively, with a piston (not shown) slidably disposed within the cylinder


60


, and a pump handle


66


for pumping hydraulic fluid through a one-way valve (not shown). The rods


64


A and


64


B are retracted by releasing the one-way valve. The internal construction of the cylinders


60


is conventional and well known, and will not be further described herein. It will be noted that each hydraulic cylinder


60


is a self-contained unit, requires no connection to an external hydraulic system, and that each hydraulic cylinder


60


is independently operated and actuated by its pump handle


66


.




The free end of each rod


64


A and


64


B is pivotally attached to opposite ends of a cross member


70


by bolts


78


A and


78


B, respectively, or other type of pivot pin. Cross member


70


is formed by a pair of parallel plates


72


maintained in spaced apart relation by at least one, and preferably a plurality of, bolts


74


which extend through spacer sleeves


76


, including a center bolt


74


A which bisects the distance between the end bolts


78


A and


78


B and the free ends of rods


64


A and


64


B. Cross member


70


is positioned so that center bolt


74


A is disposed directly above the center of recess


32


when the base


20


is resting on a horizontal surface.




Hoist chain


40


is attached to the center bolt


74


A so that chain


40


is aligned with recess


32


. Chain


40


may be attached to center bolt


74


A by any appropriate means, as by a hook, by extending center bolt


74


A through a link


42


in the chain


40


as shown in

FIG. 3

, or by other conventional means. The free end of the chain


40


is attached to a post B by any conventional means. Such means may include wrapping the chain


40


around the post B with overlapping loops, attaching a clamp, such as horseshoe clamp


44


, to the end of the chain


40


for gripping the sides of the post B, a hook


46


(seen in

FIG. 5

) which may be inserted through a mounting aperture in the post B, a gripper or clamp (not shown) which may be attached to the post B by extending a bolt through the post and one or more links in the chain


40


, etc.




Optionally, the puller


10


may include a pair of wheels


80


mounted to the base


20


for transporting the puller


10


. The wheels


80


may be attached to the base


20


by bolting a pair of mounting brackets


82


, which may have an angle iron shape formed by two flanges defining a right angle, to the rear of legs


22


, and mounting axles


84


to the upstanding flange of brackets


82


so that the axles


84


extend outboard from base


20


. Wheels


80


are rotatably mounted on axles


84


and may include pneumatic tires


86


mounted about their rims. The diameter of wheels


80


are sized and dimensioned so that the external perimeter of tires


86


are raised above the ground by between about ½″ to when the base


20


is flush against the ground A. In order to transport the puller


10


, the cross member


70


is grasped and the puller


10


is tilted rearward until the tires


86


contact the ground A and the weight of the puller


10


is balanced so that the puller may be wheeled about after the fashion of a two-wheeled cart or dolly.




In use, the puller


10


is positioned with the base


20


flush against the ground A with the post B disposed in recess


32


. The chain


40


is attached to the post B by any appropriate attachment or post gripping means. Initially the operator pumps the handle


66


of the cylinder


60


on one side of the puller


10


to raise the rod


64


A, the rod


64


B on the other side remaining stationary while the cross member


70


pivots about its end bolt


78


B. Then the operator pumps the handle


66


of the cylinder


60


on the opposite side to raise the rod


64


B while rod


64


A remains stationary, the cross member


70


pivoting about end bolt


78


B. The platforms


30


on opposite sides of recess


32


act as a guide, preventing the puller


10


from moving or walking during the pulling process. The operator may repeat the process of alternately pumping first one cylinder and then the other to rock the post B to loosen the surrounding soil, the cross member


70


acting as a second class lever alternately pivoting about one fulcrum


78


B and then the other


78


A. Finally the operator pumps both handles


66


simultaneously to exert maximum pulling force directly along the axis of the post B, without a net lateral component which might shift the post B to one side or the other, until the post B is extracted from the ground A.





FIG. 5

illustrates use of the post puller


10


to remove a post B from sloping ground A. Since the cylinders


60


may be operated independently, the rod


64


A on the lower side may be extended a greater distance than the rod


64


B on the higher side until the, cross member


70


is level, and then both rods


64


A and


64


B may bet extended simultaneously to raise the post B vertically on sloping ground.




The puller


10


has a wide base


20


with elongated legs


22


in order to distribute the pulling force over a wide area of the ground A while exerting a large pulling force on the post B, as compared to pullers which exert a pulling force only from one side of the post. By applying parallel and equal pulling forces from opposite sides of the post B, a greater pulling force may be applied for easier extraction of the post B. Advantageously, the mechanical advantage applied by the employment of parallel hydraulic cylinders


60


to extract posts from the ground reduces the likelihood of back strain and related ailments incurred during post pulling operations.




It is to be understood that the present invention is not limited to the embodiments described above, but encompasses any and all embodiments within the scope of the following claims.



Claims
  • 1. A post puller for pulling a ground-mounted post, comprising:a) a base having a first leg and a second leg in parallel, spaced apart relation for engaging the ground on opposite sides of the post; b) a first hydraulic cylinder and a second hydraulic cylinder attached to said base, each of the cylinders being an independently operable unit having a cylinder base, an extensible rod having an end slidable in the cylinder and a free end, and a pump handle attached to the cylinder base; c) a cross member having a first end pivotally attached to the free end of said first rod and a second end pivotally attached to the free end of said second rod; d) a chain depending from said cross member about halfway between said first rod and said second rod; and e) wherein said chain is attachable to the post and wherein said first and second hydraulic cylinder rods may be extended simultaneously in order to pull the post vertically from the ground.
  • 2. The post puller according to claim 1, wherein said base further comprises a crossbeam joining said first leg and said second leg in parallel spaced relation.
  • 3. The post puller according to claim 2, wherein said base is cast in one piece.
  • 4. The post puller according to claim 2, wherein said crossbeam is normal to said first leg and said second leg and wherein said crossbeam is offset from a midpoint of said first leg and said second leg, said base defining a deep channel and a shallow channel.
  • 5. The post puller according to claim 4, wherein said base further comprises:a) a first rectangular, box shaped platform joined to said base in the deep channel at the junction of said first leg and said crossbeam, said first hydraulic cylinder being mounted on the first platform; b) a second rectangular, box shaped platform joined to said base in the deep channel at the junction of said second leg and said crossbeam, said second hydraulic cylinder being mounted on the second platform; and c) wherein said first and second platforms are spaced apart to define a recess, the post being positionable in said recess.
  • 6. The post puller according to claim 1, wherein said first, and second hydraulic cylinders are single action hydraulic cylinders.
  • 7. The post puller according to claim 1, wherein said cross member comprises:a) a first elongated plate and a second elongated plate; b) a plurality of fasteners joining said first plate to said second plate; and c) a plurality of spacer sleeves disposed about said fasteners in order to maintain said first and second plates in parallel, spaced apart relation.
  • 8. The post puller according to claim 7, wherein said plurality of fasteners includes a center fastener disposed midway between the free end of said first rod and the free end of said second rod, said chain being attached to said center fastener.
  • 9. The post puller according to claim 1, further comprising post attachment means for attaching said chain to the post.
  • 10. The post puller according to claim 9, wherein said post attachment means comprises a hook.
  • 11. The post puller according to claim 9, wherein said post attachment means comprises a clamp.
  • 12. The post puller according to claim 1, further comprising a plurality of wheels attached to said base for transporting the post puller.
  • 13. The post puller according to claim 12, wherein said wheels are mounted at a rear of said base and elevated so that said wheels are raised above ground level when said legs are flush against the ground and so that said wheels engage the ground when the post puller is tilted to raise the legs above the ground.
  • 14. A post puller for pulling a ground-mounted post, comprising:a) a ground engaging base having two elongated legs and a crossbeam normal to the legs defining an H-shaped base, the crossbeam being offset from the midpoint of the two legs to define a deep channel and a shallow channel; b) a first platform joined to one of said legs and the crossbeam in the deep channel, and a second platform joined to the other said leg and the crossbeam in the deep channel, the first and second platforms defining a recess for straddling a post; c) a first single action hydraulic cylinder mounted on said first platform, the cylinder having a rod extendable from the cylinder and a pump handle attached to the cylinder for actuating the cylinder to extend and retract the rod; d) a second single action hydraulic cylinder mounted on said second platform, the cylinder having a rod extendable from the cylinder and a pump handle attached to the cylinder for actuating the cylinder to extend and retract the rod; e) an elongated cross member having a first end pivotally attached to the rod of said first hydraulic cylinder and a second end pivotally attached to said second rod, the cross member having a center; f) a link chain attached to the center of said cross member, the chain being aligned vertically above the recess defined by said platforms, the chain being attachable to the post; and g) wherein said first and second hydraulic cylinders may be actuated sequentially to rock the post from side to side and to adjust for sloping ground, and wherein said cylinders may be actuated simultaneously to pull the post from the ground without lateral movement of the post.
  • 15. The post puller according to claim 14, wherein said base is cast in one piece.
  • 16. The post puller according to claim 14, wherein said base is made from a lightweight aluminum alloy.
  • 17. The post puller according to claim 14, wherein said base and said first and second platforms are cast as a one piece unit.
  • 18. The post puller according to claim 14, further comprising a pair of wheels mounted on said base, said wheels being mounted at an elevation above ground level when said base is engaging the ground, and said wheels engaging the ground for transporting the post puller when said post puller is tilted to raise said base off the ground.
  • 19. The post puller according to claim 18, further comprising a pair of angle shaped brackets attached to said legs, each bracket having an axle mounted thereon, said wheels being rotatably mounted on said axles.
  • 20. The post puller according to claim 14, further comprising post attachment means for attaching said chain to a post.
US Referenced Citations (13)
Number Name Date Kind
2952131 Lyroudias Sep 1960 A
3358967 Harmon Dec 1967 A
3526387 Fleming Sep 1970 A
3647185 Phibbs Mar 1972 A
4244560 Hawkins Jan 1981 A
4327534 Mastalski et al. May 1982 A
4422621 Ekern Dec 1983 A
4706935 Thompson Nov 1987 A
4746096 Donnell et al. May 1988 A
5011117 Youngblood et al. Apr 1991 A
5368277 Moss Nov 1994 A
5492437 Ortiz Feb 1996 A
D372177 Hansen Jul 1996 S