U.S. patent number 3,682,434 [Application Number 05/052,825] was granted by the patent office on 1972-08-08 for sectional forms for concrete.
Invention is credited to Robert W. Boenig.
United States Patent |
3,682,434 |
Boenig |
August 8, 1972 |
SECTIONAL FORMS FOR CONCRETE
Abstract
A sectional form or mold for concrete or like materials is
constructed to permit easy detachment of the sections and removal
of the form when the material has cured or hardened. The sections,
which may be made of plastic, are united by a unique joint
comprising interlocking male and female members, retained in
interlocked relation by a rubber-like wedge or gasket in the form
of an elongated strip, driven between the joint members. The wedge
can easily be withdrawn to permit disengagement of the joint and
removal of the form sections from the hardened material. The
undamaged sections may then be reused.
Inventors: |
Boenig; Robert W. (Fairfield
County, CT) |
Family
ID: |
21980143 |
Appl.
No.: |
05/052,825 |
Filed: |
July 7, 1970 |
Current U.S.
Class: |
249/48; 138/164;
220/683; 249/134; 138/162; 138/165; 249/115 |
Current CPC
Class: |
E04G
17/00 (20130101); E04G 13/021 (20130101) |
Current International
Class: |
E04G
17/00 (20060101); E04G 13/02 (20060101); E04G
13/00 (20060101); E04g 013/02 () |
Field of
Search: |
;249/48,173,219,115,134
;285/421,419,373 ;138/158-168 ;220/75-78 ;287/189.36R,189.36D,DIG.2
;52/582,584 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Baldwin; Robert D.
Claims
What is claimed is:
1. A sectional form for concrete and like hardenable material,
comprising at least two form sections capable of being interlocked
to provide a continuous form,
each section having at each side thereof a joint member extending
longitudinally of the section,
the joint member at one side of one section being a female member
and the coacting joint member at the adjacent side of the
contiguous section being a male member freely received within and
removable from the said female member by relative lateral
displacement of said coacting joint members,
and a removable elastic wedge member driven laterally between
assembled coacting joint members to apply radial pressure
therebetween to effect interlocking and sealing of said coacting
joint members,
whereby said form may be assembled and removed laterally of the
element to be formed and may be reused.
2. A sectional form as claimed in claim 1 in which the form
sections are composed of a polymeric resin.
3. A sectional form as claimed in claim 1 in which the form
sections are composed of a thermoplastic resin extruded in sheet
form.
4. A sectional form as claimed in claim 3 in which the
thermoplastic resin in polystyrene.
5. A sectional form as claimed in claim 1 in which said coacting
joint members are formed to provide abutting sloping walls
resisting disengagement of said joint members when said wedge
member is driven home.
6. A sectional form as claimed in claim 1 in which said wedge is
composed of a synthetic elastomer.
7. A sectional form as claimed in claim 6 in which said elastomer
is a neoprene.
8. A sectional form as claimed in claim 1, in which each section is
provided on its inner face with a coating of an anti-adhesive
composition.
9. A sectional form as claimed in claim 8, in which said
anti-adhesive composition is polytetrafluoroethylene.
10. A sectional form as claimed in claim 1 in which said form
sections and said joints are integrally formed.
11. A sectional form as claimed in claim 3 in which said joints are
formed integrally with said sections by extrusion.
Description
SUMMARY OF THE INVENTION
The present invention comprises a novel form into which concrete
and like material can be poured and allowed to harden or cure. The
form is made in sections secured together by interlocking joints,
so that the sections can be disassembled and the form readily
removed and reused.
It has been common practice heretofore to pour concrete into forms
of fibrous material, such as multi-ply paper tubes, which are
stripped from the hardened concrete. Such forms are destroyed in
the stripping process and are not reusable. Furthermore when
reinforcement such as metal bars or screen is used in a concrete
column, beam, or other structural form of substantial length, and a
continuous form is used, the form must be initially sleeved over
the reinforcement. Often damage to the reinforcement, the form, or
both results as the form is being positioned.
This invention avoids these and other problems by constructing the
form in sections which are applied and removed laterally without
damage to the sections or to any pre-positioned reinforcing
elements.
The forms may be made of plastic, i.e. polymeric resins; I prefer
to use a thermoplastic resin which may be extruded in sheet form.
The joints between the sections may be integrally formed with the
sections, or may be separately formed and secured to the sections
by rivetting or bonding.
The joints between adjacent sections of the form preferably consist
of interlocking male and female parts, either of plastic or
extrudable metal such as aluminum, and are retained in interlocked
relation by a rubber-like wedge driven between the parts to provide
tightly engaged butt-joints at the inner faces of the interlocked
sections. Wedges of synthetic elastomer are especially
suitable.
Further objects and advantages of the invention will be evident
from the following detailed description when read in conjunction
with the accompanying drawing illustrative of the invention.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a view in perspective of a sectional form embodying the
invention;
FIG. 2 is a transverse section through the joint between adjacent
sections, showing the joint elements in interlocked relation;
FIG. 3 is a view corresponding to FIG. 2, but illustrating a
modification in which the joint elements are formed separately from
and secured to the respective form sections; and
FIG. 4 is an end elevation of a form of rectangular shape.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to the drawings in detail, FIG. 1 shows a form 10 of
generally oval shape and consisting of two sections 11 and 12,
interlocked by joints 15. The sections are preferably identical,
each section having a male joint element at one side and a female
joint element at the other side to reduce manufacturing cost and
inventory. The assembled form illustrated in FIG. 1 is open at both
ends, the lower end seating on the base or support on which the
concrete column is to be erected. The inner face of each section of
the form is provided with a coating 16 of an anti-adhesive material
to facilitate separation of the form from the cured concrete. The
material sold under the trade name "Teflon"
(polytetrafluoroethylene) is eminently suited for the purpose,
being highly resistant to adhesion with the concrete and moisture
resistant as well. A thin film normally suffices; the thickness of
the coating 16 is exaggerated in the drawing.
The form sections are preferably made of synthetic plastic, such as
a thermoplastic resin capable of extrusion in sheet form. When an
extruded sheet is produced, the die may be so shaped as to form
integrally with the sheet the interlocking members at each side.
The sheet may then be further processed to give the assembled form
the desired contour, i.e. the oval shape of FIG. 1, a circular or
polygonal shape, or the rectangular shape of FIG. 4. Polystyrene,
an expanded form of which has been used for load bearing walls in
houses, is suitable for use in the fabrication of the sectional
forms of the present invention, but many other plastic materials
possess the necessary mechanical strength and are as readily
fabricated, either by extrusion or other processing methods.
A preferred form of joint 15 is shown in FIG. 2. A female member on
one section comprises an outer lip 20 and an inner protuberance 21,
shaped as shown to provide a mouth in which is received a
projection 24 on the adjacent section, constituting the male member
of the joint. The rounded and enlarged head at the outer end of
projection 24 passes freely into the mouth of the female member and
is retained therein by wedge 25, which is driven into the space
between lip 20 and projection 24 by a hammer or other suitable
tool. When so driven, the wedge 25 forces the bulbous head of
projection 24 into engagement with the sloping wall of protuberance
21 to draw the sections together into tight abutted relation, and
offering high resistance to separation of the sections when the
form is poured.
The wedge is preferably formed of an elastomer such as the
synthetic rubber-like materials made by polymerization of
chloroprene, sold under the name "Neoprene." Wedges made of such
materials can readily be driven into position, serve to lock the
joint effectively and to seal against leakage, and can readily be
removed with pliers to disassemble the form.
In FIG. 3 is shown a joint 30 fabricated separately from the form
sections 11 and 12 and secured thereto by rivets 31. The male and
female members of joint 30 may be formed as shown in FIG. 2 and
need not be again described. In lieu of rivetting, other methods
such as bonding may be used to secure the joint members to the form
sections. Other materials may be used; for instance, the joint
members may be formed by extruding aluminum, and the form sections
may be of materials other than plastic when provided with a
suitable anti-adhesive coating 16 to ensure a smooth finish and
facilitate removal of the form from the cured concrete. However,
plastic form sections and joint members are preferred, whether made
separately or bonded together.
In FIG. 4 is shown a rectangular form embodying the invention, the
joints 35 being located adjacent corners of the rectangle to
facilitate separation from the cured material.
Whatever the contour of the assembled form, more than two sections
may be employed in one from if desired, but unless the column to be
cast is unusually large, two sections suffice. In the event the
column is of excessive height (or of excessive length in the case
of horizontally cast beams or slabs), or to facilitate handling and
transportation, two or more forms, each constructed as shown, may
be stacked. In that event, suitable means, such as interengaging
peripheral flanges or pin-and-socket devices are provided on
adjacent ends of the stacked sections to prevent lateral relative
displacement.
When the structure to be cast is large, imposing a heavy load on
the form, the slope of the engaged surfaces of projection 24 and
protuberance 21 should be more nearly radial to offer increased
resistance to the peripheral force tending to release the joint.
Also, the wedge 25 may be stiffened by suitable reinforcement to
increase its resistance to compression and thus enabling the joint
to resist the increased loading of the form.
It will be appreciated that plastic sectional forms afford many
advantages over the conventional laminated paper forms, in addition
to reuse. Thus, finishing of cast columns is minimized, for the
form surface is smooth and there is little flash where the sections
abut. Also, designs can be produced on the concrete by appropriate
molding or processing of the inner surfaces of the forms.
Other advantages and uses of the invention will be apparent to
those skilled in the art to which the invention relates.
* * * * *