US20140007537A1

US20140007537A1 - Holding Units for Stay in Place Molds

Info

Publication number: US20140007537A1
Application number: US13/544,306
Authority: US
Inventors: Pedro Quiles Perez
Original assignee: Individual
Current assignee: Individual
Priority date: 2012-07-09
Filing date: 2012-07-09
Publication date: 2014-01-09

Abstract

The instant invention provides stay in place molds for the construction of concrete structures comprising two boards or panels held together by a series of holding units that are fastened only to the interior surfaces of the cement panels by fastening means that are kept inside of the width of said panels. The holding units are selectively distributed at the internal cavity of the molds and are designed by a main cylindrical body having at least two internal ring units inside and two supporting plates at each one of the extremes of the main cylindrical body. The external, flat surface of the plates is permanently fastened only to the internal surface of the cement boards, thus forming strong stay in place construction molds having smooth external surfaces.

Description

This application claims priority under 35 USC 120 to U.S. patent application Ser. No. 13/135,485 filed on Jul. 7, 2011.

TECHNICAL FIELD OF THE INVENTION

This invention relates to holding units useful in stay in place molds for the construction of concrete structures. More particularly, the invention is directed to holding units able to provide stay in place molds, which are useful in the construction of monolithic concrete structures of excellent strength.

BACKGROUND OF THE INVENTION

Fiber cement panels, also known as fiber cement boards have been used in the elaboration of stay in place molds useful in the construction of concrete structures. In general terms, two fiber cement panels are vertically positioned and held together in order to create an internal cavity intended to be filled with liquid concrete mixture at the construction site.
The real challenge in the manufacture and use of said molds is to maintain both fiber cement panels held together firmly and to obtain a highly internal pressure resistance at the internal cavity of the form.
In most instances, said fiber cement panels hare held together by means of vertical and horizontal structural components which are attached internally or externally to the said panels, debilitating the whole structure. Said external components complicate the construction process, requiring external supports in order to counteract or balance the internal pressure created once the liquid cement mixture is poured inside the mold. Similarly, said external components difficult the alignment and proper connection of individual molds, as required in the formation of larger structures.
On the other hand, the use of complicated components assembled through the width of the fiber boards and passing along its internal cavity compromise the firmness and stability of the mold and the strength of the structure constructed with said mold. Internally, said structures occupy a large area of the internal cavity and thus, represents an obstruction that avoids the uniform contact and distribution of the liquid concrete mixture within the mold, which results in the formation of a non-monolithic, weak concrete structure. Externally, once the concrete structure is made, it is required to eliminate the external section of such components, which means additional work that can negatively affect the interior of the constructed structure.
Thus there is a need of stay in place fiber cement molds comprising a holding unit or spacer element, easy to manage, friendly to insert common mechanical and electrical construction features and particularly designed to increase the stability of the mold, capable of allow a uniform dispersion of internal pressure of the liquid mixture and to allow the uniform contact of the liquid cement mixture in order to provide concrete structures with excellent strength and resistance.

OBJECTS AND SUMMARY OF THE INVENTION

It is an object of the invention to provide stay in place fiber cement molds capable of holding the fiber cement boards with strong firmness, wherein the holding units are distributed exclusively in small areas of the internal cavity and without having any of their components exposed at the exterior surfaces of the fiber cement boards. Another object of the invention is to provide molds comprising fiber cement boards having excellent resistance to the internal pressure created by the liquid cement mixture, thus capable to stand said internal pressure without the need of any external supports or components.
Yet another object of the invention is to provide a mold wherein the liquid cement mixture is uniformly distributed inside its internal cavity, allowing said mixture to form strong monolithic structures. Still another object of the invention is to provide strong fiber cement molds that are able to be firmly interconnected to another mold in order to produce uniform and strong largest sizes concrete structures. Yet another object of the invention is to provide a mold capable of render concrete structures that resists high pressure and heavy weights. In an additional embodiment, another object of the instant invention is to provide a mold comprising fiber cement boards capable of incorporate insulating materials and without the need of disturb the interior of the constructed wall after the cement construction mixture is poured. In a still another object of the invention is to provide a stay in place mold having its exterior surface substantially flat, thus providing a concrete structure already having flat external surfaces. In yet another object of the invention is to provide a mold wherein distance and distribution of re bars may be easily predetermined and pre-established as demanded by or according to a given or particular construction code.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and additional features and characteristics of the embodiments of the present invention will become more apparent from the following detailed description considered with reference to the accompanying drawings, which are used herein in a manner of example only, and wherein:

FIGS. 1A-1D show different embodiments of the holding unit according to the instant invention, having a hollow and threaded elongated cylindrical main body, is having internal ring units in different predetermined positions of said cylindrical main body and having supporting lateral units fastened to each end of said elongated body. FIG. 1E represents a front view of the particular embodiment illustrated in FIG. 1D.

FIGS. 2A-2D show different embodiments of the holding unit according to the instant invention, having a solid and threaded elongated cylindrical main body, having internal ring units in different predetermined positions of said cylindrical main body and having supporting lateral units fastened to each end of said elongated body. FIG. 2E shows a front view of the embodiment illustrated in FIG. 2D.

FIGS. 3A-3D illustrate embodiments of the holding unit according to the instant invention having a hollow and non-threaded elongated cylindrical main body, having internal ring units in different predetermined positions of said cylindrical main body and having supporting lateral units fastened to each end of said elongated body. FIG. 3 E shows a front view of the embodiment illustrated in FIG. 3 D.

FIGS. 4A-4D show different embodiments of the holding unit according to the instant invention having a solid, non-threaded elongated and cylindrical main body, having internal ring units in different predetermined positions of said cylindrical main body and having supporting lateral units fastened to each end of said elongated body. FIG. 4E shows a front view of the embodiment illustrated in FIG. 4 D.

FIG. 5 represents holding unit illustrated in FIG. 1D with the corresponding preferred dimensions when using in a 4 feet per 8 feet construction board.

FIGS. 6A and 6B illustrate two embodiments of the lateral supporting plates which are connected to the ends of the elongated body of the holding unit according to the invention.

FIGS. 7A-7D illustrate different embodiments of the elongated cylindrical main body that are used in the manufacture of the holding unit according with the invention.

FIGS. 8A and 8B illustrate embodiments of the internal ring units used in the manufacture of the holding unit according to the instant invention.

FIG. 9 illustrates boards, foam panels, lateral and closing sections used in the manufacture of different embodiments of the molds according to the instant invention.

FIGS. 10, 11 and 12 illustrate molds manufactured using holding units according to the instant invention, wherein the front section of the molds have been cut off in order to show the internal details of the molds.

FIGS. 13A-13D illustrate the manufacture of molds according to the invention in order to show one particular distribution of the holding units in a mold.

FIG. 14A-14D illustrates the use of the molds according to the invention in the construction of concrete walls, using as an example the embodiment of the holding unit illustrated in FIG. 1D.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The following detailed description illustrates the invention by way of example and is not limited to the particular limitations presented herein as principles of the invention. This description is directed to enable one skilled in the art to make and use the invention by describing embodiments, adaptations, variations and alternatives of the invention. Potential variations of the limitations herein described are within the scope of the invention. Particularly, the size and shapes of the invention's elements illustrated in the discussion may be varied and still provide molds having different sizes or geometric shapes, that are within the scope of the instant invention.
In general terms, the instant invention is directed to holding units useful in the manufacture of stay-in-place construction molds and to said stay in place molds manufactured with or using said holding units thereof.
Essentially, all embodiments of the holding unit 10 herein described comprises an elongated, cylindrical main body; two or more internal ring units inserted in said elongated body at a particular and predetermined position and two lateral supporting plates connected to each one of the ends of the elongated main unit. Each one of these parts and its functions are discussed in more details below. Said holding units 10 are useful in interconnecting two parallel boards 12 and 14, thus creating an internal space 11 of a mold. The stay in place molds herein described are intended to be filled out with liquid construction mixture during the construction process of concrete or cement structures, such as houses, buildings, walls and the like, thus providing an already finished external surface that does not require further treatment such as plastering.
More particularly and in reference to the drawings, FIGS. 1-4 illustrate different embodiments the holding unit 10, according to the invention.
In FIGS. 1A-1D are illustrated embodiments of the holding unit 10, comprising an elongated, main cylindrical body 15 which is threaded and solid. Such embodiments also comprise two lateral supporting plates 16, which are connected at each end or extreme of the elongated main body 15. Details of the lateral supporting plates 16 are shown in details in FIG. 6A. It comprises a main body 17 having an external surface 18 and an internal surface 19, a substantially centered nut 20 that is internally threaded and to which each extreme or end of the elongated body 15 is threaded and securely fastened.
Similarly, embodiments shown in FIG. 1 also comprise at least two internally located rings units 21, which are inserted in elongated body 15 at a particular and predetermined position and creating an internal space 22, which provides support and security to re-bars used during the construction process as explained below in further details. The internally located rings 21, used in the embodiments shown in FIGS. 1A-1E are shown more detailed in FIG. 8A. Notice that the internal diameter 23 of the ring 21 is threaded, thus facilitating the introduction and positioning of said rings into any convenient and predetermined location of the elongated body 15. For instance, as shown in FIG. 1A, said rings may be positioned to the right side of the elongated body 15, creating the internal space 22 at the right side of holding unit 10, wherein as mentioned, re-bars are horizontally accommodated during the construction process. On the other hand, in embodiment shown in FIG. 1B, rings 21 are accommodated at the left side of the elongated body, thus creating the re-bar supporting space 22 at the left side of the holding unit 10. Similarly, and as shown in embodiments illustrated in FIG. 1C, two sets of rings 22 are positioned at the left and at the right sides of the elongated body, thus providing two re-bars horizontally oriented supporting spaces 22 at the left and right of the holding unit 10. Alternatively, as shown in embodiments in FIGS. 1D and 1E, rings 21 may be positioned at substantially the center of the elongated body 15, thus creating a re-bar supporting space 22 at the center of the holding unit 10.
Similarly, FIGS. 2A-2D illustrate different embodiments of the holding unit 10, comprising an elongated, main cylindrical body 23 which is threaded and solid. Such embodiments also comprise two lateral supporting plates 16, which are connected at each end or extreme of the elongated main body 23. As mentioned before, details of the lateral supporting plates 16 are shown in details in FIG. 6A.
Similarly, as in the embodiments already discussed in FIGS. 1A-1E, embodiments shown in FIGS. 2A-2E also comprise at least two internally located rings units 21, which are inserted in elongated body 23 at a particular and predetermined position and creating an internal space 22, which provides support and security to the re-bars horizontally oriented inside a the mold during the construction process. As mentioned before, details of the internally located rings 21 use in the embodiments illustrated in FIGS. 2A-2D are shown in FIG. 8A. Elongated supporting body 23 is threaded as in the embodiments illustrated in FIGS. 1A-1E, nonetheless, its interior is internally hollow.
In FIGS. 3A-3D the illustrated embodiments of the holding unit 10, comprising an elongated, main cylindrical body 24 which is not-threaded and internally solid. Such embodiments also comprise two lateral supporting plates 25, which are connected at each end or extreme of the elongated main body 24. Details so of the lateral supporting plates 25 are shown in details in FIG. 6B. It comprises a main body 26 having an external flat surface 27 and an internal flat surface 28, a substantially centered non-threaded round unit 29 located permanently at the center of the internal surface 28, to which each extreme or end of the elongated body 24 are introduced and further securely fastened by any known and suitable means in the art, such as gluing or welding.
Similarly, embodiments shown in FIGS. 3A-3D also comprise at least two internally located rings units 30, which are inserted in elongated body 24 at a particular and predetermined position and creating an internal space 22, which provides support and security to re-bars used during the construction process. Details of the internally located rings 30 used embodiments shown in FIGS. 3A-3D are shown in FIG. 8B. Notice that the internal diameter 31 of the ring 30 is not-threaded, and once introduced and positioning at any convenient and predetermined location of the elongated body 24, said internal rings 30 are fastened to the said position by any suitable means known ion the art, such as gluing or welding.
Embodiments shown in FIGS. 3A to 3D illustrate different relative position of said rings 30 at the elongated body 24 as illustrated previously for embodiments in FIGS. 1A-1D and 2A-2D.
Embodiments of holding unit 10 shown in FIGS. 4A-4D are similar to those illustrated in FIGS. 3A-3D, with the difference that, the elongated cylindrical main body 32 is non-threaded and hollow.
Elongated cylindrical main bodies 15, 23, 24 and 32; internal rings 21 and 30 as well as supporting plates 16 and 25 may be made of a solid, strong material, such as metal like steel or hard plastic or the like and they may be made by casting or molding as a complete piece of the holding unit 10 or as separated element, which are able to further be assembled. For instance, embodiments illustrated in FIGS. 1A-1D and 2A-2D may be provided by threading internal rings 21 into elongated bodies 15 or 23, respectively; and further positioned said rings at a predetermined position; and further threading the supporting plates 16 at each one of the ends of elongated body 15 or 23, respectively.
Similarly, embodiments illustrated in FIGS. 3A-3D and 4A-4D may be provided by assembling by introducing internal rings 30 in the elongated bodies 24 or 32 and further fastening them at a predetermined position, preferably by gluing or welding them into the corresponding elongated body, and further fastening the supporting plates 25 at each one of the ends of elongated bodies 24 or 32 using a suitable means known in the art, such as gluing or welding. As mentioned before, internal space 22 created by internal rings 21 or 30 provides a suitable accommodation space for horizontally positioned re-bars 33 at the interior of the construction mold.
The particular dimensions of the internal holding unit 10 as well as the particular position of the internal space 22 may varied depending on different factors such as the size of the desired mold, the width of the structure to be constructed with the mold, the size of horizontal 33 and vertical 34 re-bars to be introduced in the mold during the construction process, and other construction specifications dictated by particulars legal constructions codes.
As illustrated in FIG. 5, in one of the preferred embodiment of the holding unit 10 used with fiber cement boards 12 and 14 having dimensions of 4 feet per 8 feet, the main cylindrical body of the holding unit may have a length of 5.50 inches and an internal diameter of 0.5 inches; the plates 16 may have 0.125 inches thickness and 5×5 inches length with a cylindrical nut 20 of 0.5 inches in length, thus providing a holding unit 10 with a total length of 5 inches.
As explained in further details below, holding units 10 are used in the formation of molds particularly designed to be fill out with liquid concrete mixture during the construction process of concrete structures. Among other main functions of the holding unit 10 are providing excellent structural strength inside the molds capable to withstand extreme internal pressures created by the concrete mixture until it solidifies. Additionally, said holding unit 10 provides support to horizontal re-bars 33 as required by any given particular structural specification. Each external surface 17 or 27 of the lateral supporting plates in unit holding unit 10 are connected only to the internal surface 45 of the fiber cement panels 12 and 14, thus providing stay in place molds having a flat external surface 44 ready for painting once a concrete structure is constructed. The physical structure of holding unit 10 has been created exclusively to render concrete molds having extreme resistance to the internal pressure produce by liquid concrete mixture. Furthermore, holding units 10 are assembled at the internal cavity 22 in an arranged pattern that uses only near 2 percent of the internal cavity of a mold. Therefore, near 98 percent of the concrete mixture is allow to be in direct contact with itself, which produces an extremely strong concrete structures, capable to resist the weight of additional structures above them, thus allowing the construction of high concrete structures such as buildings. Furthermore, the particular distribution pattern of the holding units 10 at the interior cavity of the mold and the small thickness of the structure of the holding units 10 allows an accommodation or settlement of horizontal 33 and vertical 34 re-bars at a given and predetermined distance specified by the structural design of the construction; in such a manner that the installation of electrical or mechanical features inside the mold is free of any interferences with said holding units 10. Similarly, the strength of the resulting walls is much more resistance to earthquake motions and similar external forces, thus increasing the security of said constructions and its inhabitants. Besides, the use of holding units 10 having a thin main body allows the incorporation of internal reinforcements, if necessary or desired, thus increasing the versatility of the herein disclosed molds.
FIGS. 9A-9E illustrate the different pieces used in the manufacture of the herein disclosed molds manufactured using the holding unit 10. More particularly, FIGS. 9A and 9B illustrate fiber cement panels or boards 12 and 14, FIG. 9C illustrates a foam panel 35, optionally used as an insulating material. Similarly FIG. 9D illustrate connectors 37, which are elements that may be used in connecting different mold elements in order to increase the size of a given structure constructed using the herein disclosed molds. Finally, FIG. 9E illustrates ending connectors, which are used in order to connect the ending sections of a mold, thus providing the enclosing of the internal cavity 11 of the mold, thus avoiding the spill of the liquid cement mixture during construction. The required fiber concrete panels 12 and 14 are commercially available and may be substituted by any other suitable and similar panels. Furthermore, the male joint connectors 37, useful in connecting one mold to another mold as well as ending connectors 36, may be made from cut off concrete panels such as 12 and 14.
FIGS. 10-12 through illustrates stay in place construction mold embodiments 40, 41 and 42, wherein the upper front sections of said molds have been cut off in order to illustrate the internal components of each embodiment. Each mold embodiments 40, 41 and 42 comprises two fiber cement panels 12 and 14, positioned parallel one to the other wherein each fiber cement panel 12 have a flat substantially uniform external surface 44 and a flat substantially uniform internal surface 45.
As illustrated in FIGS. 10-12, the holding units 10 are permanently fastened at the interior cavity 11 of the mold in pattern of a series of multiple columns. Each of said columns is apart from the next one at a predetermined distance. Similarly, each holding unit 10 within a given column is also apart from the next holding unit 10 at a predetermined distance. The external surface 17 or 27, depending on the type of lateral unit used, lateral plate 16 or 25 of the holding unit 10 may be fastened to the internal surfaces 45 of fiber cement boards 12 or 14 by means of any suitable means known in the art, such as glue. Preferably, epoxy containing glue.
In some embodiments of the mold, at least one of the internal surfaces 45 of the fiber cement panels 12, 14 is permanently glued to an insulated foam panel 35. Said foam panel 35 has the same dimensions of the fiber cement panels 12 or 14. In some mold embodiments, such as mold embodiment 40, its lateral sides are free and open. Mold embodiment 42 however, comprises two male joint or interconnecting units 37, which are located along the left edges of the internal section of fiber cements boards 12. As mentioned previously, fiber cement boards 12, 14, and foam panel 35 are commercially available. Said interconnection units 37 allow the joining of individual molds in order to constructs larger size walls, as further indicated above. Similarly, each mold embodiment 40, 41 and 42 also comprises multiple internal holding units 10, which are distributed in a particular arrangement over the internal surface of fiber cement boards 12, 14, as previously explained. The external surfaces of each lateral units of the internal holding unit 10 are physically connected only to the internal surfaces 45 of the fiber cement panels 12, 14, thus creating an internal cavity 11.
On the other hand, mold embodiment 42 as illustrated in FIG. 12 has a closing unit 36, enclosing the internal cavity 11 of the mold 42. Said closing unit 36 may be made of fiber cement panel that has been cut off at the convenient size in order to enclose the internal cavity 11 of the mold 42. Said closing unit 36 may be installed once the mold is already assembled at the construction site and previous to fill the internal cavity 11 of the mold 42 with liquid concrete mixture.
A process directed to manufacture of the mold embodiment 40 is illustrated in FIGS. 13A-13D. In the first step, a series of holding units 10, having only one supporting plate 16 are permanently fastened at a predetermined positions of the internal surface 45 of the fiber cement panel 12 in a pattern of a series of multiple columns, each of said column being apart from the others at a predetermined distance and each holding unit 10 within a column being apart from the next holding 10 unit at a predetermined distance. The holding units 10 having a single lateral plate 16 are permanently fastened or fixed on the interior surface 45 of the fiber concrete panel 14 by, for instance gluing the exterior surface 17 of the said single lateral plate 16 to the interior surface 45 of panel 12; thus, the holding units 10 have no physical contact with the exterior surface 44 of the concrete panel 12. Once the holding units 10 are permanently joined to the interior surface 45 of the panel or board 12, a foam panel 35, previously perforated and preferably having the same dimensions of the fiber cement panel 12, is inserted through the elongated body 15 of the holding units 10, followed by inserting a second lateral plate 16 into the holding unit 10. After gluing the surface of the foam to the internal surface of the fiber cement panel 14 the mold 40 is provided. Notice that the second fiber cement panel 14 is permanently fixed to the free external surface 19 of the external plates of holding units 10 at its internal surface 45, thus creating the mold 40 illustrated in FIG. 10.
It should be noticed that, mold embodiment 40, has its lateral sides free and open. On the other hand, mold embodiment 41 illustrated in FIG. 11, is made by permanently gluing two interconnecting units 37, and along the left edges of the internal section of fiber cements boards 12 and 14 of mold 40. As mentioned before, said interconnecting units 37 may be made of a fiber cement board such as 12 or 14 that has been cut off at a suitable size and are useful in the joining of individual molds in order to constructs larger size walls.
The third embodiment 42, as illustrated in FIG. 12 has a closing unit 36, enclosing the internal cavity 11 of the mold 42. Said closing unit 36 may be made of fiber cement panel that has been cut off at the convenient size in order to close the internal cavity 11 of the mold 42. Said closing unit 36 may be installed once the mold is already installed at the construction site and previous to fill the internal cavity 11 of the mold 42 with liquid concrete mixture, allowing said mixture to be retained inside the internal cavity of the mold 42.
In operational terms, the mold embodiments 40, 41 and 42 are used in the construction of concrete or cement walls, houses, buildings and similar structures. FIG. 14 illustrates the assembled of mold embodiment 41 illustrated in FIG. 11 during construction of a given structure 50, wherein dowel 52 on construction site 53 is attached to the vertical re-bar 34 and wherein horizontally oriented re-bars 33 are resting on middle or internal section 21 of holding unit 10. Similarly, FIG. 14B, 14C illustrate the joining of two mold embodiments 41 in the construction of a larger size wall 57 by means of interconnecting units 37 and wherein the distribution and accommodation of vertical re-bars 34 and horizontal re-bars 33 inside the internal cavity 11 of mold embodiment 41 are shown.
While the invention has been described in conjunction with some embodiments, it is to be understood that many alternatives, modifications, and variations will be apparent to those skilled in the art in light of the forgoing description. Accordingly, the invention is intended to embrace all such alternatives, modifications and variations falling within the spirit and scope of the appended claims.

Claims

What is claim is:

1. A holding unit useful in holding two fiber cement boards or panel units together, said holding unit comprising:

an elongated cylindrical main body having a right end and a left end;

at least two rings inserted into said main elongated body;

two lateral supporting plates, each one of said plates comprising:

an main flat body having an external surface and an internal surface;

a coupling unit permanently located at the center of the internal surface of said flat body and;

wherein the left end of the main elongated body and the right end of the main elongated body are fastened to the coupling unit on the internal surface of the lateral supporting plates.

2. The holding unit as recited in 1, wherein said main elongated body has an external continuous threaded surface.

3. The holding unit as recited in 2, wherein said coupling unit is internally threaded.

4. The holding unit as recited in 3, wherein said main elongated body is internally solid.

5. The holding unit as recited in 3, wherein said main elongated body is internally hollow.

6. The holding unit as recited in 1, wherein said main elongated body has an external continuous smooth external surface.

7. The holding unit as recited in 6, wherein said coupling unit is internally non-threaded.

8. The holding unit as recited in 7, wherein said main elongated body is internally solid.

9. The holding unit as recited in 7, wherein said main elongated body is internally hollow.

11. The holding unit as recited in 1, wherein the two lateral supporting plates are detachable from the main body.

12. The holding unit as recited in 1, wherein the two main bodies of the lateral supporting plates are square.

13. A stay in place construction mold useful in the construction of concrete walls, said mold comprising:

two panels or boards positioned parallel one to the other: each panel having a substantially flat external surface and an internal surface;

multiple holding units, said holding units comprising:

an elongated cylindrical main body having a right end and a left end;

at least two rings inserted into said main elongated body;

two lateral supporting plates, each one of said plates comprising:

an main flat body having an external surface and an internal surface;

wherein the left end of the main elongated body and the right end of the main elongated body are fastened to the coupling unit on the internal surface of the lateral supporting plates and;

wherein the external surface of said squared plates are glued at the internal surfaces of the panels or boards creating a series of multiple columns, wherein each column is apart from the next one at a pre-determined distance and wherein each holding unit is separated from the next holding unit within a given column at a predetermined distance.

14. The mold as recited in claim 13, wherein the panels or boards are fiber cement panels or boards.

15. The mold as recited in claim 13, further comprising a foam panel having the same dimensions of the fiber cement panels and attached to the internal surface of one of the fiber cement panels.

16. The mold as recited in claim 13, further comprising interconnecting fiber cement units connected at one of the lateral sides of the mold.

17. The mold as recited in claim 13, further comprising closing units that enclosed the left and right ends of the mold.