GB2119103A - Measuring torque - Google Patents

Abstract

In measuring the torque of a ceiling fan a transducer for sensing the torque is located between the ceiling A and the ceiling fan D above or below the down-rod B. Both transient and steady- state torques of the fan transmitted to the ceiling is sensed by the transducer and the signal is fed via a bridge and amplifier(s) to analogue and digital voltmeters which are calibrated to measure the torque directly. <IMAGE>

Description

SPECIFICATION Torque measuring instrument for electric ceiling fan The common electric ceiling fan consists of a single-phase capacitor-run induction motor whose stator is hung from the ceiling by a down-rod. The rotor, which is located outside the stator, drives the fan blades fixed to the rotor. When the rotor is energised, a torque is exerted on the rotor which will rotate. The dynamic torque of the fan motor is transmitted to the ceiling via the down-rod in the form of a static torque. In the invention, the above fact is made used of and a static transducer, in the form of a strain gauge, is placed in a mechanical coupler between the fan and the ceiling above or below the down-rod. The static force picked up by the transducer will be proportional to the dynamic torque of the fan.

The output signal from the bridge network of the strain gauge is fed to amplifier(s) whose gain is so adjusted that its output to the analogue and digital voltmeters will read the fan torque directly. A prototype of the electroniftorquemeter has been made. Figure 1 shows the strain gauge bridge mounted on the mechanical coupler. A is the downrod, B is the support arm, C is the strain gauge, D is the base, E is the bearing and F is the rod connecting the gan. Note that when the strain gauge is mounted on the other support arm, it can measure the fan torque in the reverse direction of rotation.

Figure 2 shows the transducer assembly fitted in position between the down-rod and the fan. A is the ceiling, B is the down-rod, C is the mechanical coupler with the transducer assembly and D is the fan. Figure 3 shows the block diagram of the electronic system for measuring the fan torque.

1. A measuring instrument for the torque of electric and other ceiling fans which makes use of the fact that the dynamic fan torque at any instant is transmitted to the ceiling as a static torque through the down-rod and which measures the said static torque as the dynamic fan torque.

2. Atorque-measuring instrument as described in Claim 1 which has a transducer in the form of a strain-gauge resistance bridge housed in a mecha nical coupler located above or below the down-rod of the ceiling fan to measure the static force which is a measure of the dynamic fan torque.

3. A torque-measuring instrument as described in Claim 1 which has a mechanical coupler as described in Claim 2 coupling the down-rod to the ceiling fan such that the fan torque in either direction of rotation constitutes the static force (proportional to the dynamic fan torque) on the transducer mounted on the mechanical coupler.

4. Atorque-measuring instrument as described in Claim 1 that has electronic amplifier(s) which amplify the signals from the resistance bridge of a strain-gauge transducer as described in Claim 2 and display the output i n d in digital/analogue voltmeters as direct readings of the dynamic fan torque.

New claims or amendments to claims filed on 7 March 1983 Superseded claims 1-4 New or amended claims 1. Atorque measuring device specifically designed for ceiling fans whose down-rod is cut into two parts which are secured on the inner and outer parts of a bearing respectively such that the two parts of the down-rod can turn freely relative to each other and they are held together by a mechanical connecting rod on which the sensor (i.e. transducer) is adhered to. The sensor will detect the total torque transmitted from the fan motor and the fan blades to the ceiling at the connecting junction between the two parts of the downrod.

2. A torque measuring device for ceiling fans as described in Claim 1 where the mechanical connecting rod can be positioned to stop the relative movement of the two parts of the down-rod in the clockwise or the anticlockwise directions so that torque measurements can be made with forward or reverse motions of the ceiling fan.

3. A torque measuring system for ceiling fans incorporating the arrangement described in Claim 1 in a system which also includes electronic amplifiers, resistance bridge, digital and analogue display and recording instruments capable of measuring and recording both the steady-state and transient torques of the fan motor as well as the blades separately or together.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (3)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Torque measuring instrument for electric ceiling fan The common electric ceiling fan consists of a single-phase capacitor-run induction motor whose stator is hung from the ceiling by a down-rod. The rotor, which is located outside the stator, drives the fan blades fixed to the rotor. When the rotor is energised, a torque is exerted on the rotor which will rotate. The dynamic torque of the fan motor is transmitted to the ceiling via the down-rod in the form of a static torque. In the invention, the above fact is made used of and a static transducer, in the form of a strain gauge, is placed in a mechanical coupler between the fan and the ceiling above or below the down-rod. The static force picked up by the transducer will be proportional to the dynamic torque of the fan. The output signal from the bridge network of the strain gauge is fed to amplifier(s) whose gain is so adjusted that its output to the analogue and digital voltmeters will read the fan torque directly. A prototype of the electroniftorquemeter has been made. Figure 1 shows the strain gauge bridge mounted on the mechanical coupler. A is the downrod, B is the support arm, C is the strain gauge, D is the base, E is the bearing and F is the rod connecting the gan. Note that when the strain gauge is mounted on the other support arm, it can measure the fan torque in the reverse direction of rotation. Figure 2 shows the transducer assembly fitted in position between the down-rod and the fan. A is the ceiling, B is the down-rod, C is the mechanical coupler with the transducer assembly and D is the fan. Figure 3 shows the block diagram of the electronic system for measuring the fan torque. CLAIMS

1. A measuring instrument for the torque of electric and other ceiling fans which makes use of the fact that the dynamic fan torque at any instant is transmitted to the ceiling as a static torque through the down-rod and which measures the said static torque as the dynamic fan torque.

2. Atorque-measuring instrument as described in Claim 1 which has a transducer in the form of a strain-gauge resistance bridge housed in a mecha nical coupler located above or below the down-rod of the ceiling fan to measure the static force which is a measure of the dynamic fan torque.

3. A torque measuring system for ceiling fans incorporating the arrangement described in Claim 1 in a system which also includes electronic amplifiers, resistance bridge, digital and analogue display and recording instruments capable of measuring and recording both the steady-state and transient torques of the fan motor as well as the blades separately or together.

3. A torque-measuring instrument as described in Claim 1 which has a mechanical coupler as described in Claim 2 coupling the down-rod to the ceiling fan such that the fan torque in either direction of rotation constitutes the static force (proportional to the dynamic fan torque) on the transducer mounted on the mechanical coupler.

4. Atorque-measuring instrument as described in Claim 1 that has electronic amplifier(s) which amplify the signals from the resistance bridge of a strain-gauge transducer as described in Claim 2 and display the output i n d in digital/analogue voltmeters as direct readings of the dynamic fan torque.

New claims or amendments to claims filed on 7 March 1983 Superseded claims 1-4 New or amended claims

1. Atorque measuring device specifically designed for ceiling fans whose down-rod is cut into two parts which are secured on the inner and outer parts of a bearing respectively such that the two parts of the down-rod can turn freely relative to each other and they are held together by a mechanical connecting rod on which the sensor (i.e. transducer) is adhered to. The sensor will detect the total torque transmitted from the fan motor and the fan blades to the ceiling at the connecting junction between the two parts of the downrod.

2. A torque measuring device for ceiling fans as described in Claim 1 where the mechanical connecting rod can be positioned to stop the relative movement of the two parts of the down-rod in the clockwise or the anticlockwise directions so that torque measurements can be made with forward or reverse motions of the ceiling fan.