Patent Application
20160040442
It is well known in the art of manufacturing concrete pipe and other similar structures, such as manholes, box sections, catch basins, septic tanks and the like (hereinafter simply “product” or “products”), that a reinforcing wire cage is provided as reinforcement to produce a product of the required strength. In order to produce a quality concrete product, the reinforcing cage must be positioned within the concrete forms used to produce the product so that the cage will be a predetermined distance from the inside and outside walls of the finished product. Since the cage will be subjected to various forces during the product manufacturing process, it is important that the cage be properly positioned from the walls of the forms and that the required distance from the forms be maintained throughout the casting process. In order to accomplish the proper spacing, there are commonly provided spacing elements, called spacers, which can be fastened to the cage to space it from and maintain it the proper distance from the form walls.
In the casting process, an inner core and an outer jacket create an annular space that receives the wire cage. To properly position the wire cage, numerous spacers are placed on the wire cage. The spacers must be designed to resist the forces exerted on them during the casting process. If the spacers fall off during the casting process, the cage can move out of position, which can result in the finished product not meeting the product specifications. The two commonly used methods of producing concrete products create different forces on a reinforcing cage and thus upon the spacers installed on the wire cage. One of the common casting methods is the vibration process which involves lowering the jacket over the core after the wire cage is in place. Unless the spacers used are capable of resisting the downward axial forces applied as the jacket is lowered in place, the spacers can be dislodged or distorted. Another commonly used method of producing concrete products is the packer head process. In this process, the spacers installed on the wire cage must be capable of resisting not only the axial forces that occur, but also the forces upon the spacers as the cage twists during rotation of the packer head.
There are known and used a number of different spacers which have been designed in an attempt to resist all of the forces exerted upon the spacers during the casting process. Many spacers are formed from spring steel with an open hook at each end to provide for attaching the spacer to the reinforcing cage. Between the attaching hooks of the spacer there is typically formed a spacing nose to maintain the wire cage the proper distance from the forms. These steel spacers work well in most instances, but occasionally some of the spacers can become dislodged from the cage. Also, because of some new state requirements, steel spacers are no longer approved for use because the exposed metal can lead to rusting and result in rust spots and corrosion.
Some attempts have been made to improve the design and lower the cost of spacers by making them from plastic in the shape of a wheel with spokes and a central ring that engages a horizontal wire on the wire cage. These plastic spacers require no special tools to install. However, with known designs of this type, the forces exerted on them during the casting process may twist the spaces and cause some of them to fall off the wire cage.
There is therefore a need for an improved spacer useable in any of the known casting processes and designed so as to be capable of resisting forces in all directions so that the spacer cannot become dislodged and produce voids or other defects in the finished product. There is a further need for an inexpensive spacer that will permit easy and quick installation without the use of any special tools.
The spacer of the invention is made from plastic in the shape of a wheel with spokes that join an outer ring with a central ring that engages a horizontal wire on the wire cage. The plastic material allows limited bending of the spacer without breaking, and the central ring has a narrow slot that can be widened to provide for installation of the spacer on a cage wire. The outer ring also has an opening closed by a lock with an inter-locking mechanism or latch. Two protruding alignment bosses form a part of the latch to prevent it from twisting and disengaging. When the latch is properly engaged, the spacer will be locked in place on the wire by closing the inner ring around the wire of the reinforcement cage positively holding the spacer on the wire once it is locked in place.
As is well known to those skilled in the art of manufacturing concrete pipe and other similar products, a reinforcing wire cage is positioned within the concrete forms used to produce the product so that the cage will be a predetermined distance from the inside and outside walls of the finished product. The reinforcing wire cage typically consists of a plurality of relatively uniformly spaced horizontal and vertical wires welded at their intersections to form the circular cage. In a typical cage, the nominal spacing between the wires is 2″ or 3″ although it may be more or less. The spacer of the invention, indicated generally by the reference numeral 10, is formed from plastic or other suitable material that is strong and rigid but sufficiently flexible that it can be flexed a limited distance without breaking during installation of the spacer 10 on a cage wire 11. The spacer 10 has an inner circular ring 12 forming a hub, the inner ring 12 being connected to an outer circular ring 14 by a plurality of spaced-apart spokes 16. Between two of the spokes 17 the inner ring 12 has a gap 18 which allows the inner ring 12 to be opened at the gap 18. Similarly, the outer ring 14 has a gap 20 between the two spokes 17 to accommodate a locking mechanism indicated generally by the reference numeral 22. Although the spokes 16 are generally evenly spaced apart, there is another gap 24 in the outer ring 14 between the two spokes 26 and 28 just opposite gap 20. This gap 24 provides for the opening of gaps 18 and 20, both of which must be open in order to install the spacer 10 on a cage wire.
Each of the spokes 16, 26 and 28 extends radially outside of the outer ring 14, and the outer end of each spoke is rounded. With the spacers 10 installed on the wire reinforcement cage, the rounded ends of the spokes will assist lowering of the jacket during the casting process.
The locking mechanism or latch 22 in the gap 20 includes a yoke 30 on one side of the gap 20. The yoke 30 has spaced-apart, circumferentially extending arms 32 and 34 each of which has a plurality of teeth 33 on its inside surface. On the opposite side of the gap 20 is a circumferentially extending arm 36 that will extend between the yoke arms 32 and 34 when the gap 20 is closed. As best seen in
In order to assist in holding the spacer 10 on a horizontal cage wire 11 as the spacer is installed on the wire 11, four locking fingers 44 extend inwardly from the inner ring or hub 12. The fingers 44 are spaced a substantially equal distance around the inside surface of hub 12, and each finger extends at about a 45° angle from a radial line. Thus, as best seen in
In its normal condition prior to installation on a cage wire 11, the spacer is ‘opened’, i.e., the gaps 18 and 20 are open and gap 24 almost closed. To install the spacer 10 on a cage wire 11, the installer grips the spacer 10 between the fingers with the gap 20 in the outer ring 14 facing the wire 11. The spacer 10 is moved toward the wire 11 until the wire 11 is inside of the hub 12 and positioned in between the fingers 44. The installer then grips the spokes 17 adjoining the gap 20 and squeezes them together to force the arm 36 into the yoke arms 32 and 34 of the latch 22. This will cause the teeth 33 on the arms 32, 34 to engage the teeth 35 on arm 36 and lock the spacer 10 onto wire 11. Because of the angle of the teeth 33 and 35, the arm 36 cannot move circumferentially to disengage from the yoke arms 32, 34. Thus, with the spacer 10 locked in place on a horizontal wire 11, movement of the form jacket downwardly during the casting process will contact the outer rounded ends of the spokes 16. This movement may cause the spacer to turn about wire 11, but it cannot dislodge the spacer 10 from the wire 11. This turning of the spacer 10 during the casting process minimizes the amount of force on the spacer 10, and with the latch 22 locked, it is almost impossible for the spacer to become dislodged from the cage wire 11.
Referring now to
Similar to the first embodiment, in order to assist in holding the spacer 10 on a horizontal cage wire 11 as the spacer is installed on the wire 11, four locking fingers 44 extend inwardly from the inner ring or hub 12. In this embodiment, the fingers 44 are somewhat L-shaped in cross section. The fingers 44 are spaced a substantially equal distance around the inside surface of hub 12, and each finger extends at about a 45° angle from a radial line.
The other difference between the spacer of the embodiment of
The spacer 10 can be manufactured with different dimensions depending upon the dimensions of the wire cage and the thickness of the concrete product being produced. This spacer has been designed to be used on many cages with 2″ and 3″ mesh as well as rolled cages. The size of the spacer 10 would be designed so as to provide a range of cover from ¾″ up to 3″ of cover, which is the distance between the cage and surface of the outside form or jacket. Obviously, the exact dimensions of the spacer will depend upon the size and spacing of the wires of the cage, but with the design of the spacer of the invention, a spacer of a size to provide 1″ of cover, for example, will fit cages having different wire spacing.
It will be understood by those skilled in the art that a considerable number of spacers 10 will be installed on the wire cage at selected intervals before the cage is inserted over the core of the concrete forms. It will be evident from the above description that the spacers 10 can be quickly and easily installed without any tools. The quick installation will save considerable time and thus labor cost. When locked in place as described above, each spacer 10 is firmly locked in place so that it will not fall off the wire cage. Although the spacer 10 may turn slightly during the casting process, latch 22 will prevent the spacer 10 from becoming dislodged. Such turning movement of the spacer 10 is not sufficient to cause the spacer 10 to fall off the cage and will tend to absorb some of the forces exerted during lowering of the jacket over the wire cage and core. Such turning movement of the spacer 10 will not alter the amount of cover or the spacing effect of the spacer. The spacer 10 has no sharp edges, and the rounded ends of the spokes 16, 26 and 28 further minimize the forces on the spacer 10 as the outer-form or jacket is slipped down over the wire cage during the casting process. Once locked into place, the spacer 10 can withstand the considerable forces exerted during the entire casting process.
Having thus described the invention, it will be evident to those skilled in the art, that various other revisions and modifications can be made to the invention disclosed herein without departing from the spirit and scope of the invention. It is my intention however, that all such revisions and modifications that are obvious to those skilled in the art will be included within the scope of the following claims.
This application claims priority under 35 USC 119 to Provisional Patent Application Ser. No. 62/034,405 filed on Aug. 7, 2014, the contents of which are hereby incorporated by reference.
| Number | Date | Country | |
|---|---|---|---|
| 62034405 | Aug 2014 | US |
