An anchor puller is a key device used in geotechnical engineering,
construction, mine support, tunnel construction, and other fields
to test the pullout resistance (pullout force) of anchors (cables),
rebar, planted rebar, chemical bolts, and other anchor components.
Its core function is to apply a controlled axial tensile force to
the anchor until it reaches a preset value or fails, and accurately
measure and record this tensile force, thereby assessing whether
the anchor system's load-bearing capacity and construction quality
meet design requirements.
The following is a detailed description of its main functions and
technical specifications:
I. Main Functions
1. Tension Application: A hydraulic system (manual or electric
pump) generates a strong axial tensile force on the anchor (cable)
being tested.
2. Tension Measurement: This is the core function. A built-in
high-precision pressure sensor (or indirect conversion via a
pressure gauge) measures and displays the tensile force applied to
the anchor in real time (typically in kN or tons). 3. Displacement
Measurement (Select Models): Models equipped with a digital display
or displacement sensor can simultaneously measure the displacement
(elongation) of the anchor under tension, providing a
load-displacement curve for a more comprehensive assessment of
anchor performance.
4. Peak Hold: Automatically records and holds the maximum tension
(peak value) reached during the test for easy reading.
5. Data Logging and Output:
Digital Display: Displays real-time tension, peak value, and
displacement (if available) directly on the LCD screen.
Storage: Select advanced models can store multiple sets of test
data.
Output: Test data (tension, displacement, time, etc.) can be
transferred to a computer or mobile device via interfaces such as
USB, Bluetooth, or RS232 for convenient report generation and
analysis.
6. Control and Protection:
Pressure Stability Test: Maintains a set tension value for a period
of time (such as for acceptance load testing).
Overload Protection: Automatically stops or releases pressure when
the tension exceeds the device's maximum range, protecting the
device.
Mechanical Lockout (Safety Valve): Prevents injury from accidental
pressure release. 7. Determining Anchor Quality: Compare the
measured pullout force with the design pullout force or relevant
specifications to determine whether the anchor quality of the
anchor (cable) meets the requirements.
II. Key Technical Parameters
When selecting an anchor puller, the following technical parameters
are crucial:
1. Maximum Pull Force (Range):
This is the most critical parameter, determining the maximum anchor
force the instrument can test. Common ranges include 100kN, 200kN,
300kN, 500kN, 600kN, 1000kN, 1500kN, 2000kN, 3000kN, and even
higher.
Criteria for Selection: The instrument must be selected based on
the design pullout force of the anchor (cable) being tested and the
expected maximum test load. Generally, the instrument's maximum
range should be at least 1.2-1.5 times the expected maximum test
load. A range that is too large affects the accuracy of
small-tonnage tests, while a range that is too small makes the test
impossible.
2. Accuracy Grade:
Indicates the accuracy of the tensile force measurement. It is
usually expressed as a percentage of full scale.
Common grades: ±1% F.S. (full scale), ±0.5% F.S. The higher the
accuracy, the more reliable the test results.
Note: Accuracy requires regular calibration at a qualified
metrology institute.
3. Resolution:
The smallest change in tensile force that the instrument can
display (e.g., 0.1 kN, 0.01 kN). The higher the resolution, the
finer the reading.
4. Piston Stroke:
The maximum extension length of the hydraulic cylinder piston
(e.g., 50 mm, 80 mm, 100 mm, 150 mm). The stroke determines whether
the instrument can continue to apply tensile force without fully
extending the piston (causing it to become stuck) during
significant anchor bolt movement. This is particularly important
when testing anchor cables where significant slippage is possible.
5. Hydraulic System Operating Pressure:
The maximum oil pressure generated by the hydraulic pump (e.g.,
60MPa, 70MPa, 80MPa). Higher pressures can generate greater pulling
force with a smaller cylinder volume.
6. Pump Type:
Manual Hydraulic Pump: Pressurizes by manually turning a handle.
Simple, portable, and low-cost, it's suitable for sporadic field
testing or where power is inaccessible. However, it has a slow
pressurization speed and is relatively labor-intensive.
Electric Hydraulic Pump: Pressurizes using a motor. It offers fast
pressurization, reduced effort, and stable pressure, making it
particularly suitable for large-scale testing or where voltage
stabilization is required. It requires a power source (battery or
mains electricity), resulting in a relatively high size, weight,
and cost.
7. Power Supply (Electric Pump):
AC (220V) or DC (rechargeable battery). Battery power is convenient
for field use without power.
8. Data Function:
Display: LCD screen size, backlight, etc.
Storage Capacity: Number of test data sets that can be stored.
Communication Interface: USB, Bluetooth, RS232, etc.
Software: Supporting PC software functions (data management, report
generation, curve plotting, etc.).
9. Displacement Measurement (Optional)
Measuring Range: For example, 0-50mm, 0-100mm.
Accuracy/Resolution: For example, ±0.1mm, resolution 0.01mm.
10. Center Aperture:
The diameter of the center hole of the puller for passing the
anchor rod (for example, Φ32mm, Φ40mm, Φ50mm). This must be larger
than the diameter of the anchor rod being measured or the maximum
outer diameter of the anchor.
11. Applicable Anchor Rod Diameter Range:
The range of anchor rod (rebar) diameters for which the instrument
is designed (for example, Φ12mm - Φ32mm). This is usually related
to the supporting anchor rod (pull rod, nut, sleeve).
12. Safety Protection:
Overload protection pressure setting, safety valve type, mechanical
locking device reliability, etc.
13. Weight and Dimensions:
The weight and dimensions of the main unit, cylinder, pump station,
and accessory case affect the portability of the equipment.
14. Environmental Compatibility:
The operating temperature and humidity range.
15. Accessories:
These include various sizes of tie rods, adapters, anchors (nuts,
sleeves, clips), reaction support devices (bearing plates, jack
stands), carrying cases, etc. The versatility and adaptability of
accessories are crucial.
Summary
The core function of an anchor puller is to accurately apply and
measure axial tension to assess the pullout capacity of anchors.
When selecting an anchor puller, maximum force (range) and accuracy
are the most critical parameters, and they must meet the expected
load and accuracy requirements of the test object. Furthermore,
travel, pump type (manual/electric), data logging functionality,
displacement measurement capability (if required), and the c
