The present invention relates to an anchor point for installation in a concrete structure, for attaching hardware that is used for tethering a worker to the structure and thereby providing for fall protection.
Hardware known as a “ferrule loop insert” is often used to make structural connection to concrete structures such as concrete walls, ceilings and floors. Referring to
A concrete anchor point and method for constructing same is disclosed herein. The disclosed concrete anchor point includes an internally threaded member and a spacer. The internally threaded member and the spacer are cast in the volume of concrete. The internally threaded member terminates in an open end. The spacer has a hole extending therethrough which provides a through-hole in the volume of concrete extending from the opening in the exposed face to the open end. The spacer functions to space the open end away from the exposed face at a non-zero depth within the volume of concrete.
A method for constructing a concrete anchor point is also disclosed. The disclosed method includes providing an internally threaded sub-assembly and a spacer.
The internally threaded sub-assembly includes an internally threaded member that terminates in an open end, and a plug. The plug has at one end thereof an externally threaded portion adapted for threading into the internally threaded member and, at an opposite end thereof, a head portion.
The spacer has first and second opposite ends and a hole extending therebetween.
The method further includes threadingly inserting the externally threaded portion of the plug into the internally threaded member through the open end, receiving, at the first end of the spacer, the head portion of the plug by said hole, disposing the second end of the spacer on a concrete form for receiving wet concrete, dispensing wet concrete over at least at least a portion of the form so as to bury the internally threaded member and spacer in a volume of concrete, and thereafter removing the form to reveal an exposed face of the volume of concrete, wherein the spacer provides a through-hole in the volume of concrete extending from the exposed face to the open end, with the spacer functioning to space the open end away from the exposed face at a non-zero depth within the volume of concrete.
The method may include providing a foundation sub-assembly having a threaded member, the threaded member of the foundation sub-assembly having at one end thereof an externally threaded portion and, at an opposite end thereof, a head portion, and fluffier include threading the externally threaded portion of the threaded member of the foundation sub-assembly into the concrete form, wherein the step of disposing includes receiving, at the second end of the spacer, the head portion of the threaded member of the foundation sub-assembly by said hole.
Where the hole defines an inner surface of the spacer associated with the second end of the spacer, the method may include providing a sealing member for the second end of the spacer between the head portion of the threaded member of the foundation sub-assembly and the concrete form, and turning the head portion of the threaded member of the foundation sub-assembly so as to compress the sealing member for the second end of the spacer against the inner surface of the spacer associated with the second end of the spacer.
The method may include interlockingly engaging the head portion of the threaded member of the foundation sub-assembly with the head portion of the plug, in which case the step of turning the head portion of the threaded member of the foundation sub-assembly may be caused by turning the plug, which in turn may be caused by turning the internally threaded member of the internally threaded sub-assembly.
Where the hole defines an inner surface of the spacer associated with the first end of the spacer, the method may include providing a sealing member for the first end of the spacer between the head portion of the plug and the open end of the internally threaded member. In such case, the method may include turning the internally threaded member relative to the plug so as to cause compression of the sealing member for the first end of the spacer against the inner surface of the spacer associated with the first end of the spacer.
It is to be understood that this summary is provided as a means of generally determining what follows in the drawings and detailed description and is not intended to limit the scope of the invention. Objects, features and advantages of the invention will be readily understood upon consideration of the following detailed description taken in conjunction with the accompanying drawings.
With reference to
The spacer 14 has a hole 25 extending from an upper end 14a of the spacer through an opposite, lower end 14b of the spacer. The hole defines an inner surface 27 of the spacer, a portion 27a of which is located proximate the upper end 14a and a portion 27b of which is located proximate the lower end 14b.
Where the concrete form is plywood as is typical, the lag bolt 20 is preferably turned into the plywood without use of a pilot hole, because it is desirable to provide for a turning resistance that reduces the tendency of the bolt to loosen after it has been turned into the plywood a desired amount. The form (or “decking”) may alternatively be formed of other materials such as metal, where drilling a small pilot hole may be desirable.
The lag bolt 20 is first turned into the plywood just far enough to avoid squeezing the two washers together against the sealing member. Then, with reference to
If, for example, the sealing member is a more rigid structure like a Belleville washer, the end 14b of the spacer preferably just fits over the sealing member 22 allowing for a small clearance between the sealing member and the inner surface 27b when the sealing member is not under any significant compression, so that axial compression of the sealing member will be required to effectuate the seal.
Now with reference to
Referring back to
The internally threaded sub-assembly 16 includes an internally threaded member 17, a plug 19 comprising a threaded member 19a having a socket end 19a1 and an externally threaded end 19a2, and a sealing member 24 disposed so as to encircle the externally threaded end 19a2. The sealing member 24 has the same characteristics as the sealing member 22, and provides the same functionality.
The externally threaded end of the threaded member 19a is threaded into an internally threaded portion 17a of the internally threaded member 17. The threaded member 19a may be a standard socket head cap screw. With additional reference to
Continuing with reference to
The internally threaded member is preferably, or at least it is typically, a ferrule loop insert, but it may be a threaded coil insert or any other hardware having internal threads and at least one open end for accessing them. While a ferrule loop insert has just one open end, it should be understood that an internally threaded member for use in the present invention may have more than one open end; accordingly, use of the term “open end” is not intended to imply that there is or must also be a closed end.
In
The aforedescribed seals at the upper end and lower ends of the spacer are for sealing the spacer against wet concrete entering the spacer at the respective ends, for maintaining a through-hole in the volume of concrete extending from the opening in the exposed face to the open end of the internally threaded member.
Also, as explained above, tightening the joints established by the sealing members beyond that which may be required to effectuate a seal provides for structural rigidity, desirable for stiffening the final assembly 10 so that it is better able to withstand forces to which it may be inadvertently subjected before and during the time that the wet concrete is being poured around it.
The joint established by the sealing member 22 is broken simply by pulling (axially) the concrete form. Preferably this joint is tightened so that the force that will be required for this is not excessive, which could be of concern if there are multiple instances of the foundation sub-assembly 12 attached to one concrete form as is often the case. In consideration of this, this joint is preferably tightened to no more than about 100 pounds. On the other hand, this joint is also preferably tightened to at least about 80 pounds, and more preferably about 90 pounds, to provide for the desired structural rigidity. The compression bushing 29 advantageously provides for controlling the tightening force to be within these limits.
By contrast, there is generally no significant advantage to be gained by controlling the amount the joint associated with the sealing member 24 is tightened, beyond ensuring that it is not weaker than the joint associated with the sealing member 22, because the concrete form can be removed without breaking this joint. So in the preferred embodiment a compression bushing is omitted at this joint.
Finally, the plug 19 may be removed from the ferrule loop insert sub-assembly as shown in
Moreover, the present inventor has recognized that a concrete anchor point according to the invention may be used to provide for fall protection. An example is shown in
The depth D in
The plug 9b in
It is to be understood that, while a specific concrete anchor point and method for constructing same has been shown and described as being preferred, variations may be made, in addition to those already mentioned, without departing from the principles of the invention.
The terms and expressions which have been employed in the foregoing specification are used therein as terms of description and not of limitation, and there is no intention in the use of such terms and expressions to exclude equivalents of the features shown and described or portions thereof, it being recognized that the scope of the invention is defined and limited only by the claims which follow.
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