1. A magnetically latching solenoid comprising:
a frame;
a plunger configured to move through the frame between a first stable position and a second stable position;
at least one magnet mounted on the frame configured to produce a magnetic field through the plunger and the frame, wherein the magnetic field varies throughout the frame based upon the position of the plunger; and
at least one sensor mounted to the frame configured to detect and measure the magnetic field at a selected location.
2. The magnetically latching solenoid of claim 1, further comprising at least one ferro-magnetic bracket configured to conduct the magnetic field to the at least one sensor.
3. The magnetically latching solenoid of claim 2, wherein the at least one ferro-magnetic bracket is configured to create an air gap in which the sensor is positioned.
4. The magnetically latching solenoid of claim 3, wherein the ferro-magnetic bracket is further configured to allow changing a span of the air gap to adjust the sensitivity of the sensor.
5. The magnetically latching solenoid of claim 1, wherein the sensor is further configured to measure the magnetic field to determine whether the plunger is near one of the stable positions.
6. The magnetically latching solenoid of claim 1, wherein the sensor is positioned such that the magnetic field to be measured is obtained from a portion of the frame which saturates magnetically as the plunger nears the first stable position or the second stable position.
7. The magnetically latching solenoid of claim 6, wherein the sensor is further configured to detect the magnetic field increasing rapidly due to the saturation of the frame, thereby improving the sensitivity of the sensor to the position of the plunger.
8. The magnetically latching solenoid of claim 1, wherein the sensor comprises a Hall Effect sensor.
9. A magnetically latching solenoid comprising:
a frame;
a plunger configured to move through the frame between a first stable position and a second stable position;
at least one magnet mounted near the center of the frame such that a first magnetic field and a second magnetic field are produced by the magnet through the frame and the plunger, wherein each of the first and second magnetic fields drive a separate portion of the frame into magnetic saturation depending on the position of the plunger;
a first sensor mounted on the frame at a first location configured to detect and measure the first magnetic field at the first location of the frame; and
a second sensor mounted on the frame at a second location configured to detect and measure the second magnetic field at the second location of the frame.
10. The magnetically latching solenoid of claim 9; wherein the first sensor is configured to measure the first magnetic field to determine whether the plunger is near the first stable position, and the second sensor is configured to measure the second magnetic field to determine whether the plunger is near the second stable position.
11. The magnetically latching solenoid of claim 9; wherein the magnet is positioned on the frame such that the two magnetic fields produced by the magnet travel in opposite directions through the plunger.
12. The magnetically latching solenoid of claim 9; wherein the first and second sensors comprise a Hall Effect sensor.
13. A method for determining a position of a plunger in a magnetically latching solenoid, the method comprising:
producing, by at least one magnet, a magnetic field through a plunger and a frame of a magnetically latching solenoid;
detecting and measuring, at least one sensor mounted on the frame, the magnetic field at a selected location on the frame; and
determining, by a processor operably connected to the sensor, the location of the plunger based upon the magnetic field detected and measured by the at least one sensor.
14. The method of claim 13, further comprising mounting at least one ferro-magnetic bracket on the frame configured to conduct the magnetic field to the at least one sensor.
15. The method of claim 14, wherein mounting the at least one ferro-magnetic bracket further comprises creating an air gap between the bracket and the frame in which the at least one sensor is positioned.
16. The method of claim 13, wherein the sensor comprises a Hall Effect sensor.
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. A manual chain block comprising:
a drive shaft capable of rotating in response to a manual operational force;
a load sheave around which a load chain is looped, the load sheave being mounted coaxially to the drive shaft, supported together with the drive shaft on a frame via a bearing, and coupled to the drive shaft so that mechanical power is transmitted therebetween, via a reduction gear mechanism, wherein
the reduction gear mechanism includes a pinion gear provided on the drive shaft, reduction gears which mesh with the pinion gear, and a load gear interlocked with the load sheave and meshed with the reduction gears;
a gear cover which houses the reduction gear mechanism and includes a first bearing hole to support the reduction gear mechanism at one end of the reduction gear mechanism and serve as a bearing for the reduction gear mechanism; and
an auxiliary plate mounted on a side surface of the frame and in the periphery of the bearing for the load sheave, the auxiliary plate including a first portion on which the auxiliary plate is mounted on the side surface of the frame, a second portion extending from the first portion and spaced apart from the side surface of the frame, and a third portion extending from the second portion toward the side surface of the frame, the third portion including a second bearing hole extending in a thrust direction of the bearing for the load sheave, wherein the second bearing hole supports the reduction gear mechanism at another end of the reduction gear mechanism and serves as a bearing for the reduction gear mechanism, wherein the frame includes an insertion hole through which the load sheave and the drive shaft extend, wherein the second portion includes a center hole spaced apart from the insertion hole in the thrust direction, and wherein the insertion hole and the center hole support the bearing for the load sheave.
2. The manual chain block according to claim 1, wherein the third portion of the auxiliary plate is in contact with the side surface of the frame.
3. The manual chain block according to claim 1, wherein the second portion of the auxiliary plate has a flat rhombus shape with rounded corners.
4. The manual chain block according to claim 1, wherein the second bearing hole is formed in a tubular portion projecting toward the frame.
5. The manual chain block according to claim 4, further comprising a fixing hole to accommodate a rivet to fix the auxiliary plate to the frame, the fixing hole being formed in the first portion.