The model T-2640 tie bar force transducer, patented by and proprietary to
Helm Instrument Co., Inc., is designed for installation within a drilled
hole on the tie bar center line. Tie bar deflections as small as
one-millionth of an inch (.000001") can be measured with linear and
repeatability within one-half of one percent (.05%). Strain gages in a full
350 ohm Wheatstone bridge circuit are used to assure long term stability and
accuracy. Manufactured under laboratory conditions, all T-2640 force sensors
are matched within 1% and may be interchanged without recalibration.
The model T-2640 transducer is installed directly within a drilled hole and
permanently mounted by expanding the sensor body with front and back tapered
bushing assemblies to create a press fit. As a result of it's unique design,
the sensor is secured without pre-load, affording accurate calibration
mathematically.
On-machine Drilling
The model T-2640 transducer is available in several diameters for
installation within existing holes drilled previously to accommodate dial
indicator type devices. For machines where existing holes are not available,
Helm field machining technicians can provide on-machine tie-bar drilling
with Helm's portable gun drilling system. This specialty gun drilling
system, developed exclusively for deep hole tie bar drilling, is fixtured
directly to the machines tie bars and produces drilled holes to 96" deep at
production rates of 1.5" per minute. the drilling system can be used on any
size machine with tie bars from 2.0" diameter to 15.0" diameter. Typically,
all four tie bars of a die cast machine can be completely prepared for
transducer installation within one normal working shift.
