Method and apparatus for removing modular forms
A method and apparatus for removing modular forms includes a lever arm having a first longitudinal end and a second longitudinal end. A projection such as a hardened steel pin extends beyond the first longitudinal end for engaging a hole defined in a form. The projection extends in a direction generally parallel to a longitudinal axis of the lever arm. A fulcrum is coupled to the lever arm. The fulcrum is disposed closer to the first longitudinal end relative to the second longitudinal end. A knuckle guard is coupled to and is disposed on a same side of the lever arm relative to the fulcrum. The knuckle guard is disposed closer to the second longitudinal end relative to the first longitudinal end.
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This is a continuation-in-part application of application Ser. No. 10/839,673, filed on May 5, 2004, which is a continuation-in-part of application Ser. No. 10/012,624, filed on Dec. 7, 2001, now U.S. Pat. No. 6,817,590 B2, the disclosures of which are herein incorporated by reference in their entireties.
FIELD OF THE INVENTIONThis invention relates generally to methods and tools for building construction. It relates more particularly to a method and tool for removing modular forms from an underlying surface.
BACKGROUNDCertain building sections such as foundations for buildings or bridges are typically constructed with concrete for its advantages of high compressive strength, resistance to degradation by ground and water contact, and lower total cost as compared to stacked masonry units. These concrete building sections are usually framed by forms that create a mold into which fluid concrete is poured and cured. Forms may be of any rigid material that will withstand the pressures of poured concrete. Historically, forms were typically made from plywood with a thickness of at least one-inch, custom cut for a particular job site. These plywood forms were then strengthened with various vertical and horizontal bracing as appropriate for the project at hand.
Recent changes in the industry have led to the use of pre-fabricated modular forms or panels in standard sizes, where the modular forms are intended to be reused over numerous and varied projects. Modular forms of the type described herein are known in the art. These modular forms fit together easily and reduce the need for customized forms, thereby reducing the labor involved in arranging them to receive poured concrete. Modular forms typically include knobs that protrude from the side opposite that confining the concrete. These knobs allow bracing to be readily secured to bind adjacent forms to each other and to strengthen them against separation or rupture from the weight of concrete poured behind them.
After the concrete is cured sufficiently, usually a few days, the forms are removed. Whether custom made or prefabricated modular forms, the surface of the forms against which concrete comes in contact are pre-treated with a release agent, typically a diesel fuel based fluid, to facilitate removal without destroying the forms. Workers generally force pry bars, wedges and the like between the form and the hardened concrete to break the bond between them. Some workers use a hooked end of the pry bar to ‘ratchet’ the edge of a modular form away from the concrete structure. Using the pry bar in this way tends to deform the edge or a surface of the modular form that hinders future use of the form. This is because the pry bar's force is applied over a very limited surface area, whereas modular forms are engineered to withstand the forces of concrete applied broadly over an entire surface. Other workers use a sledge to drive a wedge or the straighter end of a pry bar between the modular form and the concrete to separate them. Both methods are used in the field and neither significantly reduces the strenuous labor of removing forms from underlying rigid concrete. Neither method eliminates the need to forcibly insert a pry bar tip between the modular form and the concrete to which it adheres, which is the most strenuous task in form stripping. Despite the release agent, many forms are bent, breached, or otherwise deformed during removal. This is a more significant concern with prefabricated modular forms since their increased cost is often recouped only through repeated use.
What is needed in the art is a method and tool to minimize or overcome some of the above deficiencies. Based on the foregoing, it is an object of the present invention to provide such a method and tool for removing modular forms from underlying concrete.
SUMMARY OF THE INVENTIONIn a first aspect of the present invention, an apparatus for removing modular forms includes a lever arm having a first longitudinal end and a second longitudinal end. A projection, preferably a hardened steel pin, extends beyond the first longitudinal end for engaging a hole defined in a form. The projection extends in a direction generally parallel to a longitudinal axis of the lever arm. A fulcrum, preferably arcuate in shape, is coupled to the lever arm. The fulcrum is disposed closer to the first longitudinal end relative to the second longitudinal end. A knuckle guard, preferably arcuate in shape, is coupled to and is disposed on a same side of the lever arm relative to the fulcrum. The knuckle guard is disposed closer to the second longitudinal end relative to the first longitudinal end.
In a second aspect of the present invention, a method of removing modular forms includes providing an apparatus with a lever arm having a first longitudinal end and a second longitudinal end. A projection extends beyond the first longitudinal end for engaging a hole defined in a form. The projection extends in a direction generally parallel to a longitudinal axis of the lever arm. A fulcrum is coupled to the lever arm. The fulcrum is disposed closer to the first longitudinal end relative to the second longitudinal end. A knuckle guard is coupled to and disposed on a same side of the lever arm relative to the fulcrum. The knuckle guard is disposed closer to the second longitudinal end relative to the first longitudinal end. The projection is inserted into a hole defined in a frame of a form to be removed from a wall. The second longitudinal end of the lever arm is moved toward the wall so as to cause the lever arm to pivot on the fulcrum and move the projection away from the wall to thereby pull the form away from the wall. The projection is inserted into one or more additional holes defined in a frame of the form, if necessary, and the step of moving is repeated for each of the additional holes receiving the projection in order to facilitate pulling the form from the wall. Preferably, the step of inserting is repeated, if necessary, by selecting an upper hole defined in the frame of the form and then selecting one or more additional holes disposed progressively lower on the frame relative to the upper hole.
If the form needs to be moved further away from the wall, the second longitudinal end of the lever arm can be inserted between the form and the wall, with the fulcrum and the knuckle guard facing away from the wall, until the knuckle guard contacts the form. The first longitudinal end of the lever arm is moved away from the wall to further pull the form away from the wall.
BRIEF DESCRIPTION OF THE DRAWINGS
A fuller appreciation for the present invention may be achieved by reference to the associated illustrations, wherein
The claw end 14 defines a tip 22. As shown in the elevational view (
The fulcrum 16 includes an abutment surface 28 for engaging a surface of hardened concrete, or any other sufficiently solid surface adjacent to the form to be removed. The abutment surface is opposite a line 30 defined by the tip 22 and the centroid of the lever arm end 18, and is shown in phantom in
In a preferred embodiment of the tool of the present invention, the lever arm is three to four feet long and made of one-inch steel stock, the notch is slightly greater than one half inch wide, and the fulcrum is a two-inch diameter steel tube section welded eight inches from the tip. This is to accommodate many of the modular forms in use having a thickness of one inch and knobs having a one-half inch diameter shank set approximately six inches inboard from an edge of the modular form.
Bracing in the form of steel bands or clips 52 interconnects the knobs of adjacent modular forms to reinforce the forms and to prevent their separation from one another. Each steel band or clip 52 mates with a shank 46 of at least two knobs on adjacent modular forms to hold them together. These bands 52 may be hingedly attached to the shanks 46 of one of the modular forms to be joined as shown in
The modular forms generally remain attached by adhesion to the underlying cured concrete and may be stripped or removed in the following manner. The claw end 14 of the tool 10 is engaged with a knob 34 such that the notch 24 engages the shank 46 underneath the cap 48. The abutment surface 28 of the fulcrum 16 is placed against the rigid concrete surface 40 adjacent to the form 36 to be stripped. Rigid concrete as used herein refers to concrete that has cured at least 24 hours. A force is applied to the lever arm 12 in the direction indicated by the heavy arrow F, which is toward the concrete surface. This force drives the claw end 14 against the cap 48, thus pulling the entire modular form away from the underlying concrete structure and breaking the adhesive bond therebetween. The tool is subsequently separated from the knob 34 and the concrete surface 40. In this manner, the tool 10 is used to strip one or more modular forms from underlying concrete without compromising the geometric or structural integrity of the form for future use.
Prior art pry bars typically include incising edges (i.e.—surfaces that define sharply acute angles at their junctures) and diverging sidewall surfaces defining the notch to better grip the shanks of a variety of nails or spikes. The tool of the present invention is directed to a single purpose. It need not grip the shank of the knob but rather presses against the cap 48 with its claw end upper surface 56, and it need not be adaptable to a variety of shank sizes.
With reference to
The apparatus 110 comprises a lever arm 112, a head or claw 114 at an end of the lever arm, and a fulcrum 116 disposed therebetween. The apparatus 110 is employed for removing forms such as, for example, 1⅛″ plywood style modular forms, in a manner similar to that explained with respect to the apparatus 10 shown in
The second portion 115 serves as a handle of the lever arm 112, and has a length which is greater than that of the first portion 113. As shown in
The lever arm 112 of the apparatus 110 is designed to aid in the removal of forms that are elevated above the footing. Removal of these forms using conventional methods and tools such as a hammer or pry bar can be dangerous because the operator of the tool is typically facing the wall while standing on narrow planks—often without a safety railing—mounted off of the back face of the forms. There is the danger of the operator falling off of the planking while performing the form removal process. Because the lever arm 112 is check-shaped, the apparatus 110 allows an operator to more safely remove elevated forms as explained below.
In operation, while standing on the planking, an operator stands with his or her back to the wall and engages a notch opening defined by the claw 114 of the apparatus 110 with a stud on the form that the form latch was previously latched on to. The operator then presses the fulcrum 116 against the form next to the form the operator is removing. Once contact is made, the operator exerts pressure on the handle 115 of the apparatus 110 so as to push the handle away from the operator's body as if the operator were performing a bench press. When the operator starts to exert pressure on the handle 115, the operator will be forcing his or her back against the wall. With the operator's back firmly pressed against the wall, the operator is in a much safer position during the form removal process.
Referring to
The apparatus 210 comprises a lever arm or handle 212 having a first longitudinal end 213 and a second longitudinal end 215. A projection 217 such as, for example, a hardened steel pin, extends slightly beyond the first longitudinal end 213 of the lever arm 212. A fulcrum 216, preferably in the form of a hollow cylinder, is coupled to the lever arm 212 at a first side 219 thereof, and is disposed therealong closer to the first longitudinal end 213 relative to the second longitudinal end 215. The apparatus 210 preferably includes a knuckle guard 221 coupled to the lever arm 212 at the first side 219 thereof, and is disposed therealong closer to the second longitudinal end 215 relative to the first longitudinal end 213. The knuckle guard 219 is in the form of a hollow cylinder but can take other practical shapes without departing from the scope of the present invention. As shown in
The apparatus 210 is designed to aid in the removal of what is known in the industry as SYMONS steel frame forms manufactured by Symons Corporation of Des Plaines, Ill., or equivalent compatible steel frame forms that define slots along the sides of the forms.
The apparatus 210 is employed on a form in which adjacent forms on each side thereof have already been removed from the face of the wall to thereby expose slots defined along sides of the form. In operation, the projection 217 is inserted into a slot defined in a side of a steel frame of the form at an upper portion of the form. Once the projection 217 is engaged in a slot, the operator pushes the handle 212 toward the face of the wall. This causes the apparatus 210 to pivot on the fulcrum 216 so as to permit the projection 217 of the apparatus 210 to pull the form away from the face of the wall. The apparatus 210 is then removed from the slot and is moved to another slot defined in the side of the frame of the form at a middle portion of the form. The procedure is then repeated. Once complete, the apparatus 210 is moved to a further slot defined in the side of the frame of the form at a lower portion of the form, and the procedure is again repeated.
At this point, the form has been partially pulled away from the face of the wall, but is likely “hung up” on the form ties. In order to completely remove the form, the apparatus 210 is then flipped end for end, and then turned so that the fulcrum 216 and the knuckle guard 221 are on the side of the handle 212 that is facing the operator. The operator then inserts the second end 215 of the handle 212 between the form and the face of the wall until the knuckle guard 221 comes into contact with the side of the form. The handle 212 is making contact with the form and the wall on its bottom and top respectively—not on the sides of the handle. A prying motion is then applied by the operator to the apparatus 210, by pulling on the handle 212, which pulls the form past the ties and frees it from the wall.
Referring to
The apparatus 310 is generally similar to the apparatus 10 of
The first and second fulcrums 316, 317 are respectively preferably of unitary construction with the first and second heads 314, 315. The first fulcrum 316 extends outwardly from the lever arm 312 to form an arcuate surface to enable the lever arm 312 to pivot thereon when the first head 314 engages a stud of a form to be removed. Similarly, the second fulcrum 317 extends outwardly from the lever arm 312 to form an arcuate surface to enable the lever arm 312 to pivot thereon when the second head 315 engages a stud of a form to be removed. As shown in
The apparatus 310 operates in a similar manner to that described with respect to the apparatus 10 of
Referring to
The apparatus 410 comprises a lever arm or handle 412 having a first longitudinal end 413 and a second longitudinal end 415. A projection 417 such as, for example, a hardened steel pin, extends slightly beyond the first longitudinal end 413 of the lever arm 412. A fulcrum 416 is coupled to the lever arm 412 at a first side 419 thereof, and is disposed therealong closer to the first longitudinal end 413 relative to the second longitudinal end 415. The apparatus 410 preferably includes a knuckle guard 421 coupled to the lever arm 412 at the first side 419 thereof, and is disposed therealong closer to the second longitudinal end 415 relative to the first longitudinal end 413. As shown in
In a preferred embodiment, the apparatus 412 is 36 inches long, the projection 417 is a {fraction (5/8)} inch diameter steel pin welded into a notch 423 defined in the first longitudinal end 413 of the lever arm or handle 412 such that the pin extends 1{fraction (3/4)} inches straight beyond the end of the first longitudinal end 413. Preferably, a center of the fulcrum 416 is located 7{fraction (1/4)} inches from the first longitudinal end 413 of the lever arm or handle 412, and preferably a center of the knuckle guard 421 is located 11{fraction (1/2)} inches from the second longitudinal end 415. Although the projection 417 is shown and described as a steel pin welded to the notch 423, the projection can be fabricated from other durable materials, be attached to the first longitudinal end 413 in other ways, or be formed integrally with the lever arm or handle 412 without departing from the scope of the present invention. Moreover, the apparatus 410 can take other practical dimensions.
The apparatus 410 is designed to aid in the removal of conventional aluminum hand-set concrete wall forms. Some of the manufacturers who fabricate forms that the apparatus 410 can remove are Symons Corporation, Durand Forms, Inc., Western Forms, and Tuff-N-Lite.
In operation and with reference to
While the preferred embodiments and methods have been shown and described, various changes and substitutions will be apparent to those skilled in the art and may be made without departing from the spirit and scope of the present invention. The embodiments and methods described above are hereby stipulated as illustrative rather than exhaustive.
Claims
1. An apparatus for removing modular forms, comprising:
- a lever arm having a first longitudinal end and a second longitudinal end;
- a projection extending beyond the first longitudinal end for engaging a hole defined in a form, the projection extending in a direction generally parallel to a longitudinal axis of the lever arm;
- a fulcrum coupled to the lever arm, the fulcrum being disposed closer to the first longitudinal end relative to the second longitudinal end; and
- a knuckle guard coupled to and disposed on a same side of the lever arm relative to the fulcrum, the knuckle guard being disposed closer to the second longitudinal end relative to the first longitudinal end.
2. The apparatus of claim 1, wherein the projection includes a hardened pin.
3. The apparatus of claim 1, wherein the projection includes a hardened steel pin.
4. The apparatus of claim 1, wherein the fulcrum is generally arcuate in shape.
5. The apparatus of claim 1, wherein the knuckle guard is generally arcuate in shape.
6. A method of removing modular forms, comprising the steps of:
- providing an apparatus including: a lever arm having a first longitudinal end and a second longitudinal end; a projection extending beyond the first longitudinal end for engaging a hole defined in a form, the projection extending in a direction generally parallel to a longitudinal axis of the lever arm; a fulcrum coupled to the lever arm, the fulcrum being disposed closer to the first longitudinal end relative to the second longitudinal end; and a knuckle guard coupled to and disposed on a same side of the lever arm relative to the fulcrum, the knuckle guard being disposed closer to the second longitudinal end relative to the first longitudinal end;
- inserting the projection into a hole defined in a frame of a form to be removed from a wall;
- moving the second longitudinal end of the lever arm toward the wall so as to cause the lever arm to pivot on the fulcrum and move the projection away from the wall to thereby pull the form away from the wall; and
- inserting the projection into one or more additional holes defined in a frame of the form, if necessary, and repeating the step of moving for each of the additional holes receiving the projection in order to facilitate pulling the form from the wall.
7. A method of removing modular forms as defined in claim 6, wherein the step of inserting is repeated, if necessary, by selecting an upper hole defined in the frame of the form and then selecting one or more additional holes disposed progressively lower on the frame relative to the upper hole.
8. A method of removing modular forms as defined in claim 6, further comprising the steps of:
- inserting the second longitudinal end of the lever arm between the form and the wall, with the fulcrum and the knuckle guard facing away from the wall, until the knuckle guard contacts the form; and
- moving the first longitudinal end of the lever arm away from the wall to further pull the form away from the wall.
Type: Application
Filed: Jan 14, 2005
Publication Date: Jun 9, 2005
Applicant: Form Puller Tool Co., Inc. (Chester, CT)
Inventor: Eugene Gargiulo (Durham, CT)
Application Number: 11/035,612