CA1270502A - Steel cable activated magnetic switch - Google Patents
Steel cable activated magnetic switchInfo
- Publication number
- CA1270502A CA1270502A CA000548049A CA548049A CA1270502A CA 1270502 A CA1270502 A CA 1270502A CA 000548049 A CA000548049 A CA 000548049A CA 548049 A CA548049 A CA 548049A CA 1270502 A CA1270502 A CA 1270502A
- Authority
- CA
- Canada
- Prior art keywords
- drum
- cable
- magnetic
- magnet
- magnetic field
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 229910000831 Steel Inorganic materials 0.000 title description 3
- 239000010959 steel Substances 0.000 title description 3
- 230000035699 permeability Effects 0.000 claims abstract description 9
- 230000004907 flux Effects 0.000 claims abstract description 7
- 238000004804 winding Methods 0.000 claims abstract description 4
- 229910052751 metal Inorganic materials 0.000 claims abstract description 3
- 239000002184 metal Substances 0.000 claims abstract description 3
- 239000000463 material Substances 0.000 claims description 6
- 229910000838 Al alloy Inorganic materials 0.000 claims description 2
- 230000005355 Hall effect Effects 0.000 claims description 2
- 235000014676 Phragmites communis Nutrition 0.000 claims description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 4
- 239000004020 conductor Substances 0.000 description 2
- 229910052742 iron Inorganic materials 0.000 description 2
- 238000010276 construction Methods 0.000 description 1
- 238000000034 method Methods 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02G—INSTALLATION OF ELECTRIC CABLES OR LINES, OR OF COMBINED OPTICAL AND ELECTRIC CABLES OR LINES
- H02G11/00—Arrangements of electric cables or lines between relatively-movable parts
- H02G11/02—Arrangements of electric cables or lines between relatively-movable parts using take-up reel or drum
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
- B65H63/00—Warning or safety devices, e.g. automatic fault detectors, stop-motions ; Quality control of the package
- B65H63/08—Warning or safety devices, e.g. automatic fault detectors, stop-motions ; Quality control of the package responsive to delivery of a measured length of material, completion of winding of a package, or filling of a receptacle
- B65H63/086—Warning or safety devices, e.g. automatic fault detectors, stop-motions ; Quality control of the package responsive to delivery of a measured length of material, completion of winding of a package, or filling of a receptacle responsive to completion of unwinding of a package
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
- G01V3/00—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation
- G01V3/08—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation operating with magnetic or electric fields produced or modified by objects or geological structures or by detecting devices
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
- B65H2553/00—Sensing or detecting means
- B65H2553/20—Sensing or detecting means using electric elements
- B65H2553/22—Magnetic detectors, e.g. Hall detectors
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Remote Sensing (AREA)
- Life Sciences & Earth Sciences (AREA)
- Electromagnetism (AREA)
- Environmental & Geological Engineering (AREA)
- Geology (AREA)
- General Life Sciences & Earth Sciences (AREA)
- General Physics & Mathematics (AREA)
- Geophysics (AREA)
- Quality & Reliability (AREA)
- Geophysics And Detection Of Objects (AREA)
Abstract
ABSTRACT
An apparatus for detecting the absence of a magnetically permeable metal cable at a cable sensing site on a rotatable winding drum, comprising: at least a portion of the drum adjacent the cable sensing site being of a lower magnetic permeability than that of the cable; a permanent magnet secured to said portion of the drum adjacent the cable sensing site and oriented such that cable wound on the drum at the cable sensing site conducts magnetic flux between the poles of the magnet; a pole piece of high magnetic permeability projecting from a pole of the magnet to a magnetic field sensing position at a surface of the drum; and a stationary magnetic sensor mounted adjacent the drum and positioned to sense the presence of a magnetic field at the magnetic field sensing position.
An apparatus for detecting the absence of a magnetically permeable metal cable at a cable sensing site on a rotatable winding drum, comprising: at least a portion of the drum adjacent the cable sensing site being of a lower magnetic permeability than that of the cable; a permanent magnet secured to said portion of the drum adjacent the cable sensing site and oriented such that cable wound on the drum at the cable sensing site conducts magnetic flux between the poles of the magnet; a pole piece of high magnetic permeability projecting from a pole of the magnet to a magnetic field sensing position at a surface of the drum; and a stationary magnetic sensor mounted adjacent the drum and positioned to sense the presence of a magnetic field at the magnetic field sensing position.
Description
~7~;0~:
The present invention relates to cable winding drums and more particularly to the remote sensing of the presence or absence of cable on a winch drum.
Winches using steel cable are extensively used in various fieldq, for example in construction and mari~ime equipment. In the use of such equipment it is often desired to detect the presence or absence of cable on the drum so that, for example, the drum can be stopped before the end of the cable is reached. One method of accomplishing this i~ to use an electrical switch inside the winch drum which is activated by physical contact with the cable, either directly or through a linkage.
With such an arrangement, slip rings are required to provide an electric connection between the switch on the rotating drum and the stationary drum support. Another disadvantage is the presence of moving parts, which may be damaged or could seize if not maintained properly.
The present invention provides an alternative sensing arrangement.
According to the present invention there is provided an apparatus for detecting the absence of a magnetically permeable metal cable at a cable sensing site on a rotatable winding drum, comprising:
at least a portion of the drum adjacent the cable sen3ing site being of lower magnetic permeability than that of the cable;
a permanent magnet secured to the portion of the drum adjacent the cable sensing site and oriented such that cable wound on the drum at the cable sensing site conducts magnetic flux ~L27Q15(~2 between the pole~ of the magnet, a pole piece of high magnetic perme~bllity projecting from a pole of the magnet to a magnetic ~ield sensing po~ition at a ~urface of the drum; and a stationary magnetic sen~or moun~ed adjacent the drum and positioned to serlse the presence of a magnetic field at the magne~ic field sensing position.
The cable on the drum acts as a ~magnet keeper" or flux conductor, forming a s~rong magnetic field between the poles of the magnet, 80 that there is very little magnetic field at the magnetic field sensing position at the end of the pole piece.
~hen the cable is removed from the sensing site, the pole piece extends the effective length of the magnet to the magnetic field ~ensing po~ition and the field i~ detected by the magnetic sen~or, to indicate that there i9 no cable at the cable sensing si~e on the drum.
In the accompanying drawings, which illustrate exemplary embodiments of the present invention:
Figure 1 is a schematic view, partially in ~ection of a ~0 winch drum equipped with an embodiment of sensing apparatus according to the pre~ent invention. The cable is shown proportionately larger than normal for the purpo~es of clarity.
Figure 2 i9 an enlarged sectional view of part A of Figure 1 showing one embodiment of the invention and the magnetic field when cable is wound upon the drum;
Figure 3 is an enlarged sectional view of part A of Figure 1 showing a second embodiment and the magnetic field when cable is absent from part of the drum;
~7~ 2 , Figure 4 i~ a par~ ~ectional view of the magnet and in~ert of Figure 2;
Figure 5 is an elevational view of the right-hand end of Figure ~ and Figure 6 is an elevational view of the left hand end of Figure 4.
Referring to the drawings, and particularly to Figure 1, there i~ shown a cable winch 10 with a stationary frame 12 carrying a rotating drum 14 with a core 13 and flanges 15.
A cable 16 is wound on the core of drum lA in plural superimposed layer3. The cable will normally be made from steel however any material having a relatively high magnetic permeability will function ~atisfactorily. To detect the absence of cable 16 from the layer immediately adjacent the core 13, the drum is provided with a sensing apparatu~ generally de~igna~ed 180 As shown in the Figure 2 embodiment, the sensing apparatu~ 18 consist~ of a permanent magnet 20 fitted within an insert 11 into the drum core 13 adjacent one of it~ end flanges 15. The magnet is oriented axially of the drum. The insert 11 i~ made from a material having a lower magnetic permeability than the cable, a suitable material being an aluminum alloy or a ~uitable plastic.
A ~oft iron pole piece 22 extend~ from the pole of magnet 20 through the flange 15 and to a magnetic field sen~ing position 23.
The insert 11 can be held within the drum by known mechanical mean~ such a~ by an interference fit or flange means or the like (not ~hown). A stationary magnetic sen~or 2~ is mounted on the winch frame 10 by any known mechanical means (not shown), to detect a magnetic field at the end of pole piece 22 as the pole piece 22 pa~ses the sensor 24 during rotation of the drum.
Figure~ 4, 5 ancl 6 show the insert ll which 1~ of part-cylindrical form with the magnet 20 and pole piece 22 embedded therein.
Referring to Figure 3, there i9 ~hown an embodiment wherein the whole drum is made from a material having a lower magnetic permeability than that of the material of the cable.
As illustrated in Figure 2, when cable 16 is wound on the drum over the cable sensing site between the pole~ of magnet 20, the cable acts as a flux conductor or "magnet keeper" and conducts magnetic flux between the poles of the magnet 20. The magnetic field at the magnetic field ~ensing position is low and below the level at which it will be detected by sensor 24. As Rhown in Figure 3, when the cable is absent from the cable sensing ~ite, the magnetic flux is conducted through the ~oft iron pole piece 22 to the magnetic field sensing po~ition 23 at the end flange 15 of the drum 14. The magnetic ~ensor 24 detects this relatively strong magnetic field as the pole piece 22 pas~es the sensor during rotation of the drum. The output of the sensor i9 used to generate a signal that may in turn be used to produce a warning for a winch operator that the cable i~ almost depleted.
The magnetic field ~ensor may be any one of a number of known devices. For example it may be a magnetic field detector, a Hall Effect sensor or a reed switch.
The illustrated embodiment of the invention shows the magnet embedded in the drum and oriented parallel to its axis. It is to be under~tood that other arrangements are possible within the scope of the invention, provided the magnet is positioned and oriented to use the cable at a cable sensing site as a magnet keeper.
The present invention relates to cable winding drums and more particularly to the remote sensing of the presence or absence of cable on a winch drum.
Winches using steel cable are extensively used in various fieldq, for example in construction and mari~ime equipment. In the use of such equipment it is often desired to detect the presence or absence of cable on the drum so that, for example, the drum can be stopped before the end of the cable is reached. One method of accomplishing this i~ to use an electrical switch inside the winch drum which is activated by physical contact with the cable, either directly or through a linkage.
With such an arrangement, slip rings are required to provide an electric connection between the switch on the rotating drum and the stationary drum support. Another disadvantage is the presence of moving parts, which may be damaged or could seize if not maintained properly.
The present invention provides an alternative sensing arrangement.
According to the present invention there is provided an apparatus for detecting the absence of a magnetically permeable metal cable at a cable sensing site on a rotatable winding drum, comprising:
at least a portion of the drum adjacent the cable sen3ing site being of lower magnetic permeability than that of the cable;
a permanent magnet secured to the portion of the drum adjacent the cable sensing site and oriented such that cable wound on the drum at the cable sensing site conducts magnetic flux ~L27Q15(~2 between the pole~ of the magnet, a pole piece of high magnetic perme~bllity projecting from a pole of the magnet to a magnetic ~ield sensing po~ition at a ~urface of the drum; and a stationary magnetic sen~or moun~ed adjacent the drum and positioned to serlse the presence of a magnetic field at the magne~ic field sensing position.
The cable on the drum acts as a ~magnet keeper" or flux conductor, forming a s~rong magnetic field between the poles of the magnet, 80 that there is very little magnetic field at the magnetic field sensing position at the end of the pole piece.
~hen the cable is removed from the sensing site, the pole piece extends the effective length of the magnet to the magnetic field ~ensing po~ition and the field i~ detected by the magnetic sen~or, to indicate that there i9 no cable at the cable sensing si~e on the drum.
In the accompanying drawings, which illustrate exemplary embodiments of the present invention:
Figure 1 is a schematic view, partially in ~ection of a ~0 winch drum equipped with an embodiment of sensing apparatus according to the pre~ent invention. The cable is shown proportionately larger than normal for the purpo~es of clarity.
Figure 2 i9 an enlarged sectional view of part A of Figure 1 showing one embodiment of the invention and the magnetic field when cable is wound upon the drum;
Figure 3 is an enlarged sectional view of part A of Figure 1 showing a second embodiment and the magnetic field when cable is absent from part of the drum;
~7~ 2 , Figure 4 i~ a par~ ~ectional view of the magnet and in~ert of Figure 2;
Figure 5 is an elevational view of the right-hand end of Figure ~ and Figure 6 is an elevational view of the left hand end of Figure 4.
Referring to the drawings, and particularly to Figure 1, there i~ shown a cable winch 10 with a stationary frame 12 carrying a rotating drum 14 with a core 13 and flanges 15.
A cable 16 is wound on the core of drum lA in plural superimposed layer3. The cable will normally be made from steel however any material having a relatively high magnetic permeability will function ~atisfactorily. To detect the absence of cable 16 from the layer immediately adjacent the core 13, the drum is provided with a sensing apparatu~ generally de~igna~ed 180 As shown in the Figure 2 embodiment, the sensing apparatu~ 18 consist~ of a permanent magnet 20 fitted within an insert 11 into the drum core 13 adjacent one of it~ end flanges 15. The magnet is oriented axially of the drum. The insert 11 i~ made from a material having a lower magnetic permeability than the cable, a suitable material being an aluminum alloy or a ~uitable plastic.
A ~oft iron pole piece 22 extend~ from the pole of magnet 20 through the flange 15 and to a magnetic field sen~ing position 23.
The insert 11 can be held within the drum by known mechanical mean~ such a~ by an interference fit or flange means or the like (not ~hown). A stationary magnetic sen~or 2~ is mounted on the winch frame 10 by any known mechanical means (not shown), to detect a magnetic field at the end of pole piece 22 as the pole piece 22 pa~ses the sensor 24 during rotation of the drum.
Figure~ 4, 5 ancl 6 show the insert ll which 1~ of part-cylindrical form with the magnet 20 and pole piece 22 embedded therein.
Referring to Figure 3, there i9 ~hown an embodiment wherein the whole drum is made from a material having a lower magnetic permeability than that of the material of the cable.
As illustrated in Figure 2, when cable 16 is wound on the drum over the cable sensing site between the pole~ of magnet 20, the cable acts as a flux conductor or "magnet keeper" and conducts magnetic flux between the poles of the magnet 20. The magnetic field at the magnetic field ~ensing position is low and below the level at which it will be detected by sensor 24. As Rhown in Figure 3, when the cable is absent from the cable sensing ~ite, the magnetic flux is conducted through the ~oft iron pole piece 22 to the magnetic field sensing po~ition 23 at the end flange 15 of the drum 14. The magnetic ~ensor 24 detects this relatively strong magnetic field as the pole piece 22 pas~es the sensor during rotation of the drum. The output of the sensor i9 used to generate a signal that may in turn be used to produce a warning for a winch operator that the cable i~ almost depleted.
The magnetic field ~ensor may be any one of a number of known devices. For example it may be a magnetic field detector, a Hall Effect sensor or a reed switch.
The illustrated embodiment of the invention shows the magnet embedded in the drum and oriented parallel to its axis. It is to be under~tood that other arrangements are possible within the scope of the invention, provided the magnet is positioned and oriented to use the cable at a cable sensing site as a magnet keeper.
Claims (10)
PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. An apparatus for detecting the absence of a magnetically permeable metal cable at a cable sensing site on a rotatable winding drum, comprising:
at least a portion of the drum adjacent the cable sensing site being of a lower magnetic permeability than that of the cable;
a permanent magnet secured to said portion of the drum adjacent the cable sensing site and oriented such that cable wound on the drum at the cable sensing site conducts magnetic flux between the poles of the magnet;
a pole piece of high magnetic permeability projecting from a pole of the magnet to a magnetic field sensing position at a surface of the drum; and a stationary magnetic sensor mounted adjacent the drum and positioned to sense the presence of a magnetic field at the magnetic field sensing position.
at least a portion of the drum adjacent the cable sensing site being of a lower magnetic permeability than that of the cable;
a permanent magnet secured to said portion of the drum adjacent the cable sensing site and oriented such that cable wound on the drum at the cable sensing site conducts magnetic flux between the poles of the magnet;
a pole piece of high magnetic permeability projecting from a pole of the magnet to a magnetic field sensing position at a surface of the drum; and a stationary magnetic sensor mounted adjacent the drum and positioned to sense the presence of a magnetic field at the magnetic field sensing position.
2. The apparatus of Claim 1 wherein the portion of the drum adjacent the cable sensing site consists of an insert into which the permanent magnet and the pole piece are embedded.
3. The apparatus according to claim 1, wherein the drum is made from a material of low magnetic permeability.
4. The apparatus according to claim 3, wherein the drum is made from an aluminum alloy.
5. The apparatus according to claim 4, wherein the magnet and the pole piece are fitted within the drum core.
6. The apparatus according to claim 1, wherein the magnet is parallel to the axis of the drum, and the pole piece projects to an end of the drum.
7. The apparatus according to claim 1, wherein the magnetic and pole piece are fitted within the drum core.
8. The apparatus according to claim 1, 5 or 7, wherein the magnetic sensor is a magnetic field detector.
9. The apparatus according to claim 1, 5 or 7, wherein the magnetic sensor is a Hall Effect sensor.
10. The apparatus according to claim 1, 5 or 7, wherein the magnetic sensor is a reed switch.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000548049A CA1270502A (en) | 1987-09-28 | 1987-09-28 | Steel cable activated magnetic switch |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000548049A CA1270502A (en) | 1987-09-28 | 1987-09-28 | Steel cable activated magnetic switch |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1270502A true CA1270502A (en) | 1990-06-19 |
Family
ID=4136538
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000548049A Expired CA1270502A (en) | 1987-09-28 | 1987-09-28 | Steel cable activated magnetic switch |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1270502A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1405810A1 (en) * | 2002-10-02 | 2004-04-07 | Heidelberger Druckmaschinen Aktiengesellschaft | Wire bobbin and method for detecting remaining wire |
| WO2017027892A1 (en) * | 2015-08-07 | 2017-02-16 | De Paiva Jose Alexander | Electrical cable extension reel with safety switch |
-
1987
- 1987-09-28 CA CA000548049A patent/CA1270502A/en not_active Expired
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1405810A1 (en) * | 2002-10-02 | 2004-04-07 | Heidelberger Druckmaschinen Aktiengesellschaft | Wire bobbin and method for detecting remaining wire |
| DE10246075A1 (en) * | 2002-10-02 | 2004-04-22 | Heidelberger Druckmaschinen Ag | Wire spool and residual wire detection method |
| US6921044B2 (en) | 2002-10-02 | 2005-07-26 | Heidelberger Druckmaschinen Ag | Wire spool and remaining wire detection method |
| CN100343148C (en) * | 2002-10-02 | 2007-10-17 | 海德堡印刷机械股份公司 | Metal wire roll and identifying method for residual metal wire |
| WO2017027892A1 (en) * | 2015-08-07 | 2017-02-16 | De Paiva Jose Alexander | Electrical cable extension reel with safety switch |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKLA | Lapsed |