Measuring Principle
Both direct and inverted pendulum use the same principle of operation: the plumb line.
Due to the effect of the force of gravity, a wire, fixed at one end, acts as a perfect vertical reference. Measuring consists in recording the movements of one or more points of structure, with respect to the gravitational vertical line made by a plumb line . In the case of the inverted pendulum, the wire is anchored at the base, generally at the bottom of a hole extending into the foundations and considered fixed. At the opposite end, the wire is connected to a special float, free to move in a cylindrical tank, usually filled with oil that always remains perfectly vertical position relative to the anchor point.
Due to the effect of the force of gravity, a wire, fixed at one end, acts as a perfect vertical reference. Measuring consists in recording the movements of one or more points of a structure, with respect to the gravitational vertical line made by the plumb line . In the case of the inverted pendulum, the wire is anchored at the base, generally at the bottom of a hole in the foundation, considered fixed. At its opposite end, the wire is connected to a special float, free to move in a cylindrical tank usually filled with oil which maintains the float in a perfect vertical position relative to the anchor point.
The straight pendulum is constituted of:
- Upper system of wire fixing
- Guide plate for the correct positioning of the wire
- Lower system of wire fixing with weight
- Cylindrical tank and damper
The upper fastening system of the wire is achieved by a winch, complete with tensioning roller, on which the wire is wounded on for few laps and then blocked by friction, without affecting the integrity and resistance with forces or restrictions on the section.
The wire’s upper fastening system consists of a winch, complete with tensioning roller, round which the wire is wound a few times and then blocked by friction, without affecting integrity or resistance by using force or restriction on the section.
The winch allows retrieval of the spare wire; necessary for extension due to tensioning of the plumb line
The wire guide plate is installed under the winch. The wire will achieve its hinge point on a notch formed on one end of the plate. The pendulum’s hinge point is on a notch at one end of the plate .
The inverted pendulum consists of:
- Anchor weight with lower wire hooking system;
- loat with bar and stabilization weight;
- Cylindrical stainless steel suspension tank;
The pendulum wire is fixed at its lower end to a ring, designed to prevent the formation of nicks which would decrease the resistance to traction .
Attached to the ring there is a weight that has the function to allow the descent of the wire in the hole, up to the anchor point; the whole system is blocked with a cement jet.
A weight attached to the ring, allows the wire to descend into the hole to the anchor point; the whole system is then fixed in place with cement.
At the top, the wire is hooked, using a similar ring system as above, to a threaded bar, which at its other end is engaged in the mechanical unit of the float, which has the function of stabilizing and regulating wire tension.
The suspension tank is fixed to the structure to be monitored
The measuring of the movements of the two pendulums, that is of the wire part of the pendulum, can be performed manuallywith portable removable coordinometer EGS model, or automatically using the different automatic coordinometers produced by us.
The possibility to take both automatic and periodic manual measurements for the same point ensures backup measurements and independent monitoring of the automatic system are available.
Our technicians will suggest the most suitable model of automatic coordinometer according to specific requirements, site characteristics and monitoring system to be implemented
Pendulums of different shapes and dimension for special applications or depths, can be created by us on our clients’ request.
Technical specifications
Direct Pendulum (cod. PND1101001)
| Cylindrical Weight |
30 Kg (optional 100 kg) |
| Material of the weight |
Varnished iron |
| Suggested fluid |
SAE 50-90 OIL or similar product |
| Dimensions of the tank |
Diameter 450mm; height 220mm, with lid 305mm |
| Material of the tank |
Stainless steel |
| Wire fixing |
Nickel-plated brass ring |
Inverted Pendulum (cod. PND1201001)
| Caisson for the oil |
Diameter 650, height 500mm |
| Material of the tank |
Stainless steel |
| Anchoring Weight |
35 kg |
| Material of the floating |
Stainless steel |
| Floating strenght (standard version) |
300N (upon request 1000N and 2000N) |
| Material of the anchoring weight |
Varnished iron |
| Suggested fluid |
SAE 50-90 Oil or similar |
| Wire fixing |
Nickel-plated brass ring |
Wire Pendulum
| Material |
Stainless steel |
| Section |
1 mm (optional 1,5 mm) |
Accessories and related Products
| Digital IP Telependulum Image Processing Technology |
Digital Automatic Coordinometer with Image Processing Technology, web server integrated, for the automatic readings of direct and inverted pendulum, readings storage, data transmission, functions of local “alarming”, no movable parts |
| EGS – Portable Electronic Telependulum |
Portable Telependulum for manual readings of direct and inverted pendulum |
| Electromagnetic Telependulum |
Automatic Coordinometer with electro-magnetic technology for automatic readings of direct and inverted telependulum |
| Laser Telependulum |
Laser Telependulum for the automatic readings fo direct and inverted telependulum, no movable parts |
Technical Assistance
If you have any requests or questions about our instruments or if you have special needs that require different solutions from the standard, please contact us. Our team will provide all the necessary information and will be very happy to work with you to study, develop and customize instruments and solutions suitable for your specific needs
All information in our datasheet is subject to change without prior notice.
Please check the datasheet/details carefully and contact Pizzi Instruments for further information
