Systems and methods for indicating the location of various structural members in concrete members

The locating of structural members disposed within the interstices of a concrete member can be accomplished by employing at least one indicator capable of showing the position of the structural member. The indicator also can show the directional location of the support members. The indicator of the present invention generally connects to a post member. This post member provides vertical support for the indicator system. A clamping assembly is attached to the post member and connects the structural member to the indicator system for fixing the location of the structural member. The clamping system can also identify the location of the structural member, and the indicator can then be provided to show the directional line of the structural member. Typically, the post member is sized to a predetermined length so that the longitudinal dimension of the indicator system corresponds to the thickness of the concrete member. In this way, after the concrete is cast, the indicator will be visible at the surfaces of the concrete member.

BACKGROUND OF THE INVENTION 
This invention relates to systems and methods for indicating the location 
of structural members, such as pre-tensioned and post tensioned cable, 
strands and rods, which are disposed within the interstices of concrete 
members. 
Many concrete members, such as concrete slabs or beams, employ 
high-strength structural members as the means of pre-tensioning or 
post-tensioning these members for providing strength requirements. In the 
building construction industry a serious safety concern is posed if these 
post-tension members are damaged or severed when holes used for anchorage 
devices or utility lines are drilled into the slab after the concrete has 
hardened. More specifically, since these tension members are the primary 
source of strength, these concrete members may fail if the tension members 
are severed. 
The present methods of locating structural members are limited to the use 
of x-ray photography and/or magnetic induction devices. However, the x-ray 
photography and magnetic induction devices cannot distinguish between the 
mild standard concrete steel of concrete reinforcing elements and that of 
the structural members, respectively. Therefore, severing of the 
structural members often results. Moreover, the more reliable x-ray 
photography requires evacuation of the area being exposed during location 
of structural members for safety reasons. 
With respect to other non-analogous uses such as underground utility lines 
in U.S. Pat. No. 3,523,515 and U.S. Pat. No. 3,927,637, devices have been 
provided which indicate the depth below ground depth and/or water level of 
those utility lines. In these devices, the depth can be read by an 
observer at the ground and/or water level surface. 
Therefore, a need exists for a system for easily and accurately indicating 
the location of structural members located in the interstices of concrete 
members, in order to avoid the unwanted severing of these structural 
members when for example, holes are drilled into the concrete member. 
SUMMARY OF THE INVENTION 
The above-described existing needs have been met by the indicator system of 
the present invention which is used in locating structural members within 
a concrete member. Thus, the locating of such structural members is 
accomplished by employing at least one indicator means capable of showing 
the position of the structural member in the concrete member. Furthermore, 
the indicator means also can show the directional location of the support 
members. The indicator means of the present invention generally connects 
to a post member. This post member provides vertical support for the 
indicator system. A clamping assembly is attached to the post member and 
connects the structural member to the indicator system for fixing the 
location of the structural member. 
The clamping system can also identify the location of the structural 
member, and the indicator means can then be provided to show the 
directional line of the structural member. Typically, the post member is 
sized to a predetermined length so that the longitudinal dimension of the 
indicator system corresponds to the thickness of the concrete member. In 
this way, after the concrete is cast, the indicator means will be visible 
at the surfaces of the concrete member. Depending on the location of the 
structural member, the clamping assembly is preferably slidably attached 
to, and movable to a plurality of positions along, the post member. The 
clamping member can also include coupling means for interlocking engaging 
with the structural member. A slidable clamping assembly can also be 
provided which comprises a sleeve section in sliding engagement with the 
post member. Moreover, the coupling means can further include a slot for 
facilitating the engagement and disengagement of the structural member 
therewithin. 
In a preferred indicator system, a pair of indicator means are joined to 
the respective ends of the post member. Each indicator means is preferably 
positioned so that it will be substantially vertically aligned with the 
structural member, or in a plane substantially parallel to the 
longitudinal axis of the coupling means, for fixing the directional line 
of the structural member. Generally, the indicator means comprises a 
substantially flat outer surface, and directional indicator means elements 
pointed in the directional line of the structural member. The indicator 
means further can also include a holder section for joining the indicator 
means to the post member, and a fastener slot for joining the indicator 
system to an underlying concrete form. 
The foregoing and other objects, features and advantages of the invention 
will become more readily apparent from the following detailed description 
of a preferred embodiment which proceeds with reference to the drawings.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT 
Referring now to FIGS. 1 and 2, the structural member indicator system of 
this invention, denoted 10, is disposed within the interstices of a 
concrete member 30, in this case a concrete slab. Indicator system 10 is 
more specifically depicted in FIGS. 3-5, and comprises a post member 12 
which supportedly connects at its respective ends 14 to top and bottom 
indicator means 16 and 18, respectively. Indicator means 16 includes a 
base portion 22 having a substantially flat outer portion 24 and including 
a holder portion 26 to which post member 12 is joined. A retaining collar 
13 is joined about holder 26 for maintaining indicator system 10 in 
position within concrete member 30. The indicator means 16, which is 
generally elongated in shape, comprises a substantially rectangular 
support portion 15 and a pair of pointed directional indicators 17 
extending from the elongate edges 19 at one end of indicator means 16. 
Typically, one of the flat surfaces 24 will rest on a complementary 
substantially flat underlying surface, typically a concrete form 32. Flat 
surface 24 is generally in a horizontal plane during use. Therefore, post 
member 12 will preferably extend at right angles to the flat surfaces and 
in a substantially vertical plane. Slot 28 is provided in base sections 16 
and 18 having a central aperture 29 which passes entirely through base 
portion 22 and surface 24 (see FIG. 5). Fastening means 25, in the form of 
a nail in FIG. 4, pass within aperture 29 and attach the indicator system 
10 to a concrete form 32 (see FIG. 2). 
A clamping assembly 40 is connected for sliding engagement via sleeve 
portion 42 to post member 12 between indicator means 16 and 18. Coupling 
means 46, preferably in the form of a snap clamp, is joined to sleeve 
portion 42 by arm portion 44. A slot 48 is disposed within the coupling 
means 46 for facilitating the engagement and disengagement of cable 50 
from within the coupling means. The coupling means extend in a 
longitudinal plane in substantially the same direction as the pointed 
directional indicators 17 which are shaped to indicate the direction that 
the line of the cable extends. Therefore, the pointed directional 
indicators 17 will provide a directional marker for locating the cable 50 
and for indicating the direction in which the cable extends within the 
coupling means 46. 
Preferably, the indicator system 10 is fabricated from a polymeric or metal 
material, depending on cost and use requirements of a given installation. 
In operation, structural members 50 are first installed in position over 
the construction forms 32. Each clamp assembly 40 is then placed onto each 
of the cables 50 by moving slot 48 the cable, and then into coupling means 
46. Next, post member 12 is inserted through sleeve 42. Previously, post 
member 12 was precut to a size equal to the predetermined thickness of the 
concrete member 30. The bottom indicator means 18 is attached to the 
bottom of post member 12 by inserting lower end 14 into holder portion 26 
of the top indicator. The post member is then aligned vertically and 
bottom indicator 18 is joined to the form 32 by driving nail 25 thereinto. 
The top indicator means 16 is attached to the top of post member 12 by 
inserting the upper end 14 into holder portion 26 of the bottom indicator. 
The concrete member 30 is then cast. When the concrete member 30 has set, 
the forms are removed and the indicator system 10 remains in place and in 
alignment with the outer surface of the concrete member so that indicator 
means 16 and 18 depict the location and directional location of the cables 
50. 
Having illustrated and described the principles of my invention in a 
preferred embodiment thereof, it should be readily apparent to those 
skilled in the art that the invention can be modified in arrangement and 
detail without departing from such principles. We claim all modifications 
coming within the spirit and scope of the accompanying claims.