A unique instrument for measuring the strength of new or existing construction materials in situ utilizing the established principle of resistance to penetration.
Technical
The principle of the Windsor Pin™ system is that a spring
drives a steel pin into the surface of the material. Since the depth
of penetration is inversely proportional to compressive strength,
the device provides a fast and safe way of determining the in situ
strength of material.
The spring is loaded by tightening the retraction nut until the
trigger mechanism latch closes to hold the spring in place. The
stored potential energy is 91 lbs. in (108 NM). With the spring
loaded it is compressed to a distance of 0.8 inches. Thus once the
trigger is pulled there is enough force to test compressive strength
of concrete to a maximum of 5300 PSI (36.9 MPA). The pin is made
of a special high strength steel specifically for building material
penetration and can be used about seven times. It should be replaced
if the length is reduced sufficiently for it to pass a go/no-go
gauge. Not doing so will severely impact results.
With the chuck on both the micrometer and pin driver, flat surfaces
can be easily and accurately measured. Simply make sure the chuck
rests against the surface and pull the trigger. After the pin has
penetrated the surface, clean the hole with the provided lower,
measure depth of penetration and compare to the previously prepared
chart for the compressive strength of your material. Charts for
typical mortar and concrete is provided.
The recommended practice is to take seven readings discarding
the two readings farthest from the mean. By doing this the possibilities
of striking a flaw or near surface piece of hard aggregate and using
the resulting penetration to calculate strength are sufficiently
reduced. Grinding the surface flat before testing pro- duces more
consistent results.
With the chuck removed the pin driver is capable of accurately
testing mortar joints. By inserting the V-barrel into the mortar
joint the pin will directly penetrate at the center of the joint.
By following a similar procedures as above the compressive strength
of the mortar joint can be accurately and safely tested. A similar
v-shape for the micrometer facilitates measurement. |
