What is claimed is:
1. A mounting device assembly comprising:
a circuit board having an electronic component mounted thereon;
a heat sink comprising a base, and a plurality of fins arranged on the base;
a unitary mounting device for mounting the heat sink to the circuit board, the mounting device comprising a body defining an opening for receiving the electronic component therethrough such that the electronic component contacts the base, the body comprising a plurality of beams surrounding the electronic component and being sandwiched between the base and the circuit board;
locking means for locking the heat sink to the mounting device without interference to the fins; and
latching means for latching the mounting device to the circuit board.
2. The mounting device assembly as claimed in claim 1, wherein the beams comprises a pair of longitudinal beams, and the locking means comprises a plurality of cutouts defined in opposite longitudinal sides of the base of the heat sink, and a plurality of fasteners formed on the longitudinal beams of the mounting device and engaging in the cutouts.
3. The mounting device assembly as claimed in claim 2, wherein the latching means comprises a pair of locking slots defined in the circuit board on opposite sides of the electronic component, and a pair of latches formed on bottoms of the longitudinal beams and engaging in the locking slots respectively.
4. The mounting device assembly as claimed in claim 3, wherein the circuit board defines a plurality of pairs of locating openings surrounding the electronic component, and the body of the mounting device comprises a plurality of pairs of feet received in the locating openings respectively.
5. The mounting device assembly as claimed in claim 3, wherein the base of the heat sink defines a pair of holes in opposite lateral side portions thereof, the beams further comprise a pair of lateral beams, a pair of posts is formed on the lateral beams, and the posts are fittingly received in the holes.
6. A mounting device assembly comprising:
a circuit board having an electronic component mounted thereon;
a heat sink comprising a base, and a plurality of fins provided on the base; and
a mounting device for mounting the heat sink to the circuit board, the mounting device comprising:
a body defining an opening for extension of the electronic component therethrough to contact the base, and comprising a plurality of beams surrounding the electronic component and being sandwiched between the base and the circuit board;
engaging means integrally formed from the body for engaging with the heat sink at outsides of the fins; and
latching means integrally formed from the body for latching the mounting device to the circuit board.
7. The mounting device assembly as claimed in claim 6, wherein the base of the heat sink defines a plurality of cutouts in opposite longitudinal sides thereof, the beams comprise a pair of longitudinal beams, and the engaging means comprises a plurality of fasteners formed on the longitudinal beams and engaging in the cutouts.
8. The mounting device assembly as claimed in claim 7, wherein the circuit board defines a pair of locking slots on opposite sides of the electronic component, and the latching means comprises a pair of latches formed on bottoms of the longitudinal beams and engaging in the locking slots.
9. The mounting device assembly as claimed in claim 8, wherein the circuit board defines a plurality of pairs of locating openings surrounding the electronic component, and the body of the mounting device comprises a plurality of pairs of feet received in the locating openings respectively.
10. The mounting device assembly as claimed in claim 8, wherein the base of the heat sink defines a pair of holes in opposite lateral side portions thereof, the beams further comprise a pair of lateral beams, a pair of posts is formed on the lateral beams, and the posts are fittingly received in the holes.
11. A mounting device assembly comprising:
a circuit board having an electronic component mounted on a surface thereof;
a heat sink;
a mounting device being arranged between the circuit board and the heat sink and around the electronic component;
fasteners being formed on one of the mounting device and the heat sink and snappingly engaged with the other of the mounting device and the heat sink, thus fastening the mounting device to the heat sink; and
latches being formed on one of the mounting device and the circuit board and snappingly engaged with the other of the mounting device and the circuit board, thus latching the mounting device to the circuit board.
12. The mounting device assembly of claim 11, wherein the mounting device is a substantial rectangular plate.
13. The mounting device assembly of claim 12, wherein four pairs of feet are formed on four corner portions of the mounting device, each pair of the feet are oriented perpendicular to each other and fittingly engaged in the circuit board.
14. The mounting device assembly of claim 11, wherein the fasteners are formed on the mounting device and snap a base plate of the heat sink which is in contact with the electronic component.
15. The mounting device assembly of claim 11, wherein the latches are formed on the mounting device and snap a surface of the circuit board opposite to the surface where the electronic component mounted.
16. The mounting device assembly of claim 11, wherein said mounting device is provided with an upward plane supporting a base of the heat sink, and defines an opening to allow one of said heat sink and said electronic component to extend therethrough to contact the other.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. Monitoring apparatus for monitoring electrical drive current for an electric motor, comprising signal generating means operable to provide a signal which varies in response to variations in the drive current, and analysis means operable to analyze the signal to determine the rate of change of the drive current and to provide an alarm signal in the event that the rate of change of the drive current continues to be in excess of a predetermined rate for a period which is in excess of a predetermined time.
2. Monitoring apparatus according to claim 1, wherein the signal is a voltage derived from the drive current.
3. Monitoring apparatus according to claim 1, wherein the voltage is derived from at least part of the current flowing through an impedance.
4. Monitoring apparatus according to claim 3, wherein said part of the drive current is derived by means of a sensefet device.
5. Monitoring apparatus according to claim 1, wherein the apparatus includes sensor means operable to provide to the analysis means a digital signal representing the value.
6. Monitoring apparatus according to claim 1, wherein the analysis means is operable to store periodically the value of the signal, and to analyze the rate of change by reference to a sequence of stored values.
7. Monitoring apparatus according to claim 1, wherein the analysis means includes a microprocessor or microcontroller programmed to perform analysis as aforesaid.
8. Monitoring apparatus according to claim 1, wherein the analysis means includes differentiator means operable to differentiate the signal.
9. Monitoring means according to claim 8, wherein comparator means are provided, operable to compare the output of the differentiator means with a threshold value.
10. Monitoring apparatus according to claim 8, wherein timer means are provided to measure the length of time for which the output of the differentiator means exceeds a threshold value.