GB2150286A - Monitoring free-running properties of rollers - Google Patents
Monitoring free-running properties of rollers Download PDFInfo
- Publication number
- GB2150286A GB2150286A GB08429382A GB8429382A GB2150286A GB 2150286 A GB2150286 A GB 2150286A GB 08429382 A GB08429382 A GB 08429382A GB 8429382 A GB8429382 A GB 8429382A GB 2150286 A GB2150286 A GB 2150286A
- Authority
- GB
- United Kingdom
- Prior art keywords
- roller
- rotation
- rate
- timer
- predetermined
- 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.)
- Granted
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
- G01P1/00—Details of instruments
- G01P1/07—Indicating devices, e.g. for remote indication
- G01P1/08—Arrangements of scales, pointers, lamps or acoustic indicators, e.g. in automobile speedometers
- G01P1/10—Arrangements of scales, pointers, lamps or acoustic indicators, e.g. in automobile speedometers for indicating predetermined speeds
- G01P1/103—Arrangements of scales, pointers, lamps or acoustic indicators, e.g. in automobile speedometers for indicating predetermined speeds by comparing the value of the measured signal with one or several reference values
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M13/00—Testing of machine parts
- G01M13/04—Bearings
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
- G01P15/00—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration
- G01P15/16—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by evaluating the time-derivative of a measured speed signal
Abstract
Free running rollers for conveying web material along a path can brake and mark the material or their bearings become worn. For monitoring the free-running properties of rollers and thus the bearing wear, a roller R is set into rotation at a first predetermined rate and the time taken for the rate of rotation of the free-running roller to fall from the first predetermined value to a second and lower predetermined value is noted on the rate of rotation of the roller at a predetermined time interval is noted and these values are compared with corresponding values derived from a standard roller. Pulses representing the rotation of the roller are produced by a reflective target W passing a photo-electric detector. An electronic circuit for using the pulses to effect the measurements and comparisons is also described. <IMAGE>
Description
SPECIFICATION
Method and device for monitoring free-running properties of rollers
This invention relates to a method and to a device for monitoring the free-running properties of a non-driven roller and in particular for monitoring the bearing wear of such a roller.
The term "non-driven roller" as used in this Specification denotes a roller which is free-running and which is held at each end in a roller mounting, there being either internal bearings in the roller or an external bearing in the mounting at each end of the roller. Such rollers are often mounted in an array or assembly to define a path along which a web of material is conveyed.
Roller bearings tend to wear out or to pick up dust particles and in both cases the free-running properties of the roller are gravely impaired. When the rollers are part of an array of rollers which is used to convey web material along a path, it is required that all the rollers should rotate freely, since any which do not can act as a brake on the web material and mark it.
In some roller arrays there are as many as 600 rollers and thus a means of monitoring the free-running property of each roller in situ would be a great advantage. Furthermore the act of removing a roller of the type which has internal bearings often affects the bearings and thus it is inadvisable to remove such rollers for testing.
According to one aspect of the present invention there is provided a method of monitoring the free-running properties of a roller mounted for rotation on bearings therefor comprising the steps of
(i) setting the roller into rotation at a first predetermined rate of rotation,
(ii) initiating a time measurement when the roller is rotating at said predetermined rate of rotation,
(iii) allowing the roller to rotate under free running conditions,
(iv) measuring by means of a non-contact method the rate of rotation of the roller,
(v) noting the time taken for the rate of rotation of said roller to fall to a second predetermined value lower than said first and/or noting the rate of rotation of said roller after a predetermined time interval, and
(vi) comparing the time taken for the rate of rotation to fall to said second value and1or the rate of rotation after said predetermined time interval with corresponding values derived from a standard roller.
As the rate of deceleration of a free-running roller which has been caused to rotate is much greater when roller bearings are beginning to deteriorate or when dust is present in the bearing than the deceleration rate of a roller with unworn bearings, the present method can be used to monitor or determine the wear of the bearings. It is thus useful for monitoring an array of rollers used to convey web material along a path, so that rollers with worn bearings can be replaced before the wear becomes so bad that the rollers brake and mark the material.
According to another aspect of the present invention there is provided a device for use in monitoring the free-running properties of a roller mounted for rotation on bearings therefor, comprising means mounted or mountable on or provided in the roller for initiating a pulse for each revolution of the roller, a sensor for detecting pulses initiated by said means, a first timer which derives information from the sensor and which is adapted to provide an indication when the roller is rotating at a first predetermined rate of rotation, a second timer which derives information from the sensor and which is adapted to provide an indication that the roller is rotating below a second predetermined rate of rotation, an interval timer which is set by the first timer and which is adapted either to indicate that a preset time interval has elapsed or which is adapted to record the time interval taken for the rate of rotation of the roller to fall from the first to the second predetermined rate of rotation, and means for comparing these time intervals with the corresponding values of a standard roller.
The method and device of the present invention are preferably used for monitoring the bearing wear of a non-driven roller but can also be used for monitoring the free-running property of a roller when the free-running property has deteriorated by reasons other than wear, for example from over-oiling of the bearings.
The standard roller may be one which has been fitted with new bearings and which is known to rotate freely. However, the standard provided by such a roller may in fact be too high and in such a case the standard roller may be one in which an acceptable amount of wear has occurred. With a preferred embodiment of the present device the comparison is not made each time with the standard roller but with values obtained from the standard roller and incorporated in an electrical circuit. In order to obtain the most reliable results, the standard roller and the roller being monitored are mounted in similar mountings, as the form of mounting can affect the rate of deceleration.
In carrying out the present method it is preferred to select a predetermined time interval from when the roller being monitored reaches the first predetermined rate of rotation and if the rate of rotation of the roller during this time interval has not fallen below the predetermined second rate of rotation then the roller system being monitored is deemed to have passed the test and is serviceable, but if before the time interval has elapsed the rate of rotation falls below the predetermined lower second rate of rotation the roller system is deemed to have failed the test and it must be removed to have new bearings installed. By appropriate selection of the time interval, the mount of wear which causes a roller to pass or fail the test can be adjusted as desired.
A suitable time interval can be derived from the equation:
wheretis the time interval vr is the first rate of rotation in radians per second,
v2 is the second rate of rotation in radians per second,
a is the deceleration rate for a standard roller in radians per second per second.
Preferably a beam of light is directed onto the rotating roller and the light reflected back from the roller is received as light pulses which are used to determine the length of time taken for the rate of rotation to fall to said second predetermined rate of rotation andlorto determine the rate of rotation after said predetermined time interval.
In order to initiate reflected light pulses from the roller, it is convenient to fasten a piece of reflective tape to the roller and to direct the beam of light thereon. However if the roller being monitored is highly reflective then a piece of non-reflective tape can be adhered to the roller.
Preferably the sensor is adapted to produce a light beam for reflection off the tape to generate a pulse in the sensor and preferably modulated infra-red light is used as the beam of light. This avoids interference from ambient or artificial light in the area where the roller system is being monitored.
In the present method because testing takes place with the roller running freely and the deceleration rate is sensed by a non-contact sensor, no external loads are imposed on the roller system that might effect the free running performance of the roller. The rotational speeds used in the test are within the normal operating range of the rollers and thus effects outside that range are avoided.
In the present device, the first and second timers are preferably both digital timers, and the interval timer is preferably arranged to time out after a preset time interval, means being present to indicate if the second timer has timed out before the interval timer.
Most preferably the device comprises visual indications to show that a) pulses are being generated or a light beam is being produced, b) the first timer has timed out and the device is set to monitor, c) the interval timer is operating, d) the interval timer has timed out before the second timer has timed out, and e) the second timer has timed out before the interval timer has timed out.
In order to enable the invention to be more readily understood, reference will now be made to the acompanying drawings, which illustrate diagrammatically and by way of example an embodiment thereof, and in which:
Figure 1 is a perspective view of a device for monitoring the bearing wear of a non-driven roller,
Figure 2 is a perspective view showing the device in use, and
Figure 3 is a diagram of a circuit suitable for incorporation in the device.
Referring now to Figure 1 there is shown a device D for monitoring the bearing wear of a non-driven roller.
The device D is presented in the form of a box capable of being held in the hand and being, for example, 155 x 92 x 45 mm in size.
The device incorporates an optical sensor OS adapted to produce a beam of modulated infra-red light which leaves the device through a window OS, and, after reflection, can be detected at an input window OS2.
The device is also provided with various signal lamps PL, S, T, F and P, the purpose of which will be described later, a reset button and an external knob VT of a timer.
Figure 2 shows how the device is used to provide an indication of the free running properties or bearing wear of a roller R held by a mounting shaft MS in two mounts M, the roller R including two internally mounted bearings (not shown). The roller carries a target W which is arranged to be detected by the device once in each revolution of the roller. The target may be a piece of reflective material intended to receive light transmitted through the window OS1, and to reflect it back through the window OS2. However, if the surface of the roller is highly reflective then the target may be of non-reflective material.
Referring now to Figure 3, there is shown the circuit diagram of the device D, all the electronic components being housed within the box. The optical sensor OS is arranged to produce a modulated beam of infra-red light which is transmitted through the window OS,. When the light from the beam is reflected off the target
Won the roller R a light pulse will be received at the window 082. The pulses are taken through an inverter gate 11 and serve to operate a green lamp PL so as to indicate that a pulse is being received. The inverted pulses are also fed to a NOR-gate NO1 which is capacitively coupled to a second inverter gate 12 to differentiate them and then applied to the power inputs of two digital timers T1 and T2.The timers T1 and T2 run continuously and are therefore reset by the edge of the pulse generated when the target passes the optical sensor. The timers are digital timers so as to ensure a fast reset.
The sensor pulse from the NOR-gate NO1 is also applied to the clock input of a D-type latch L1 which has the output of timer T1 as its data input. The timer T1 is arranged so that, in operation, it will always have timed out and the data input to the latch L1 will remain at "O" until the sensor pulse arrives at the clock input of the latch before the timer T1 has timed out. This will occur when the rate of rotation of the roller is sufficiently high to generate pulses at the required frequency. Thereupon Q of the latch L1 will change state and an "O" will be applied to a NAND-gate N1 thus applying a "1" to the data input of a second D-type latch
L2.At the next pulse from the optical sensor, the outputs of the latch L2 will change state and an indicator lamp Swill be illuminated to indicate that the roller has reached a sufficient rate of rotation above the first predetermined rate of rotation for the test to be started, the latch L1 producing a "1" at8and remaining set until this rate of rotation has been obtained whereupon Q becomes "0".
The 0 output of the latch L2 is applied to the NAND-gate N1 so that the system remains set as the rate of rotation falls again, the latch L2 being set when the latch L1 is set and being self-sustaining through the gate
N1 to remain set once set irrespective of the state of the latch L1.
As the rate of rotation falls, the point is reached at the first predetermined rate of rotation where the timer
T1 times out and the latch L1 is reset, thus applying a "1" to both inputs of a NAND-gate N2 and applying an "0" to a digital timer T3, thereby starting it timing, and at the same time illuminating a timing indicator lamp
T.
At the end of the timing period of the timer T3, the output 3 of the timer returns to "0" thus applying "0"s to the NOR-gate NO2 and a latching "1" into the latch L3. At the next clock pulse the latch L3 is activated and illuminates a pass lamp P. However, if before the timer T3 times out the rate of rotation of the roller falls to such an extent that the timer T2 times out, then all "0"s are applied to a NOR-gate NO3 thus latching a "1" into a latch L4 and illuminating a fail lamp F.
When one or other of the pass or fail lamps is illuminated and respective latch is set, then the output of a
NAND-gate N3 is set to a "1 " which is then applied to the NOR-gate NO1 thus preventing any further pulses entering the system. The outputs therefore remain set until the reset button RS is operated to apply a clear signal to all the latches and reset them ready to enable another test to take place.
Each of the power inputs to the logic circuits labelled +5V is supplied by a battery pack BP which conveniently comprises four cells each of 1 .25V.
In the use of the device to monitor the free running properties or bearing wear of the roller R, a target W is applied to the roller and the roller is set into rotation by hand or by some other means and then allowed to run freely. The device D is hand held insuch a position that a light beam leaving through the window OS, will be reflected back to the window OS2 by the target W once each revolution of the roller. It will thus be appreciated that the time between successive reflections provides an indication of the rate of rotation of the roller. In the operation of the device, the timer T1 and the latch L1 are set to make an effective measure of time between pulses generated by the rotation of the roller referred to the first and higher predetermined rate of rotation.At the same time, the timer T2 and the latch L4 are set to make an effective measure of the rate of rotation referred to the second and lower predetermined rate of rotation.
As the speed of rotation of the roller is increased past the first predetermined rate of rotation, the set lamp
Swill be illuminated to show that the test can be commenced. The roller is then allowed to run freely and when the rate of rotation falls through the first predetermined rate of rotation in the downward direction, the timing lamp Twill be illuminated to indicate that a test has started and that the timer T3 has been activated.
The latches L3 and L4 serve to indicate whether by the time the timer T3 times out the rate of rotation of the roller as determined by the timer T2 and latch L4 has passed through second lower predetermined rate of rotation. If the rate of rotation is above the predetermined rate, the output of the timer T2 is a "1 " and the latch L4 remains reset when the timer T3 times out and, through the NOR-gate NO2, sets the latch L3 thus illiminating the pass lamp P to indicate that the roller is satisfactory as compared with a standard roller.
The latch L3 acts via the NAND-gate N3 to disable the NOR-gate NO1 to prevent further input pulses generated by the roller from entering the system so there will be no pulses to reset the timer T2 or to set the latch L4 and thus illuminate the fail lamp F.
If, however, the rate of rotation of the roller drops below the second predetermined rate before the timer
T3 times out, then a pulse becomes available to set the latch L4 and thus illuminate the fail lamp F. The pulse acts via the NAND-gate N3 to disable input pulses through the NOR-gate NO1 so that even when the timer3 times out there are no pulses to set the latch L3.
There is the possibility that, if the rate of rotation of the roller has dropped to the second predetermined rate as the timer T3 times out, the same pulse will set both the latches L3 and L4 together so that both the pass and fail lamps are illuminated. Depending upon the tolerance allowed for a roller, this may be regarded as either pass or a fail condition.
As indicated above, the timers T1 and T2 and the latches L1 and L4 are set for values appropriate to the first and second predetermined rates of rotation empirically determined from experience of a "standard" roller, that is to say one which preferably has new bearings and is known to rotate with the required degree of freeness. Alternatively, of course, the "standard" roller may be one with lower degree of acceptability and which has already undergone a predetermined amount of wear. This latter alternative niay be preferable in the case where the device is adapted to compare the time taken for the rate of rotation to fall from the first to the second rate rather than to compare the rates after a predetermined time interval.
Alternatively the values may be derived from the equation
as previously defined.
In monitoring operation the working speed of the rollers was about 200 r.p.m. This rate of rotation was taken as the first prdetermined or upper rate of rotation. The lower or second predetermined rate of rotation was taken as 160 r.p.m. and the time interval set on timer T3 derived from the aforesaid equation:
was 6 seconds.
Thus all the roller systems monitored where T2 timed out before 6 seconds were deemed to have failed while all those where T2 had not timed out in 6 seconds were deemed to have passed.
Claims (15)
1. A method of monitoring the free running properties of a roller mounted for rotation on bearings therefor comprising the steps of
(i) setting the roller into rotation at a first predetermined rate of rotation,
(ii) iniating a time measurement when the roller is rotating at said predetermined rate of rotation,
(iii) allowing the roller to rotate under free running conditions,
(iv) measuring by means of a non-contact method the rate of rotation of the roller,
(v) noting the time taken for the rate of rotation of said roller to fall to a second predetermined value lower than said first and/or noting the rate of rotation of said roller after a predetermined time interval, and
(vi) comparing the time taken for the rate of rotation to fall to said second value andior the rate of rotaton after said predetermined time interval with corresponding values derived from a standard roller.
2. A method as claimed in Claim 1, wherein said non-contact method involves directing a beam of light onto the rotating roller, receiving the light reflected back from the roller as a light pulse and using the reflected light pulses to determine the length of time taken for the rate of rotation to fall to said second predetermined rate of rotation andior to determine the rate of rotation after said predetermined time interval.
3. A method as claimed in Claim 1 or 2, wherein the predetermined time interval is derived from the equation:
where t is the time interval, v, is the first predetermined rate of rotation in radians per second, v2 is the second predetermined rate of rotation in radians per second, and a is the deceleration rate in radians per second per second for a standard roller.
4. A method as claimed in any one of Claims 1 to 3, wherein a piece of reflective tape is fastened to the roller being monitored and the beam of light is directed thereon.
5. A method as claimed in any one of Claims 1 to 4 wherein modulated infra-red light is used as the beam of light.
6. A method as claimed in Claim 1, wherein said non-contact method involve magnetic means activatable by a magnet in the roller to generate pulses and using the pulses to determine the length of time taken for the rate of rotation to fall to said second predetermined rate of rotation and. or to determine the rate of ratation after said predetermined time interval.
7. A method of monitoring the free-running properties of roller mounted for rotation on bearings therefor substantially as hereinbefore described with reference to the accompanying drawings.
8. A device for use in monitoring the free-running properties of a roller mounted for rotation on bearings therefor, comprising means mounted or mountable on or provided in the roller for iniating a pulse for each revolution of the roller, a sensor for detecting pulses initiated by said means, a first timer which derives information from the sensor and which is adapted to provide an indication when the roller is rotating at a first predetermined rate of rotation, a second timer which derives information from the sensor and which is adapted to provide an indication that the roller is rotating below a second predetermined rate of rotation, an interval timer which is set by the first timer and which is adapted either to indicate that a preset time interval has elapsed or which is adapted to record the time interval taken for the rate of rotation of the roller to fall from the first to the second predetermined rate of rotation, and means for comparing these time intervals with the corresponding values of a standard roller.
9. A device as claimed in Claim 8, wherein the first and second timers are both digital timers.
10. A device as claimed in Claim 8 or 9, wherein the sensor is a light sensor and said means in the roller is adapted to provide a light pulse.
11. A device as claimed in Claim 10, wherein the sensor is adapted to produce a light beam for reflection off said means to generate a pulse in said sensor.
12. A device as claimed in Claim 11, wherein said light beam is modulated infra-red light.
13. A device as claimed in any one of Claims 8 to 12, wherein the interval timer is arranged to time out after a preset time interval and means are present to indicate if the second timer has timed out before the interval timer.
14. A device as claimed in any one of Claims 8 to 13, wherein the device comprises visual indications to show that a) pulses are being generated, b) the first timer has timed out and the device is set to monitor, c) the interval timer is operating, d) the interval timer has timed out before the second timer has timed out, and e) the second timer has timed out before the interval timer has timed out.
15. A device for monitoring the free-running properties of a roller mounted for rotation on bearings therefor substantially as hereinbefore described with reference to the accompanying drawings.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB838331263A GB8331263D0 (en) | 1983-11-23 | 1983-11-23 | Roller monitor |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB8429382D0 GB8429382D0 (en) | 1985-01-03 |
| GB2150286A true GB2150286A (en) | 1985-06-26 |
| GB2150286B GB2150286B (en) | 1986-11-19 |
Family
ID=10552227
Family Applications (2)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB838331263A Pending GB8331263D0 (en) | 1983-11-23 | 1983-11-23 | Roller monitor |
| GB08429382A Expired GB2150286B (en) | 1983-11-23 | 1984-11-21 | Monitoring free-running properties of rollers |
Family Applications Before (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB838331263A Pending GB8331263D0 (en) | 1983-11-23 | 1983-11-23 | Roller monitor |
Country Status (1)
| Country | Link |
|---|---|
| GB (2) | GB8331263D0 (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2598515A1 (en) * | 1986-05-07 | 1987-11-13 | Cofreth Sa | Digital device for measuring the speed of an alternator, in particular for starting and monitoring an emergency electricity generator unit |
| EP0296295A1 (en) * | 1987-06-26 | 1988-12-28 | COFRETH Société Anonyme: | Digital alternator speed-measuring apparatus, especially for starting and controlling an emergency power generator |
| DE102008024373A1 (en) * | 2008-05-20 | 2009-11-26 | Hauni Maschinenbau Ag | Checking the rotational behavior of a roller |
| DE102008047026A1 (en) * | 2008-09-13 | 2010-03-25 | Dräger Medical AG & Co. KG | Method for determination of wear condition of bearing for shaft or axle, involves propelling shaft or axle supported by bearing on measuring number of revolutions with driving motor |
| DE102010005636A1 (en) * | 2010-01-25 | 2011-07-28 | Siemens Aktiengesellschaft, 80333 | Method for evaluating operating performance of bearing of computer tomography apparatus, involves evaluating measured circulation period of bearing and/or curve characteristic for evaluating operating performance of bearing |
-
1983
- 1983-11-23 GB GB838331263A patent/GB8331263D0/en active Pending
-
1984
- 1984-11-21 GB GB08429382A patent/GB2150286B/en not_active Expired
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2598515A1 (en) * | 1986-05-07 | 1987-11-13 | Cofreth Sa | Digital device for measuring the speed of an alternator, in particular for starting and monitoring an emergency electricity generator unit |
| EP0296295A1 (en) * | 1987-06-26 | 1988-12-28 | COFRETH Société Anonyme: | Digital alternator speed-measuring apparatus, especially for starting and controlling an emergency power generator |
| DE102008024373A1 (en) * | 2008-05-20 | 2009-11-26 | Hauni Maschinenbau Ag | Checking the rotational behavior of a roller |
| DE102008047026A1 (en) * | 2008-09-13 | 2010-03-25 | Dräger Medical AG & Co. KG | Method for determination of wear condition of bearing for shaft or axle, involves propelling shaft or axle supported by bearing on measuring number of revolutions with driving motor |
| DE102008047026B4 (en) * | 2008-09-13 | 2016-06-09 | Drägerwerk AG & Co. KGaA | ventilator |
| DE102010005636A1 (en) * | 2010-01-25 | 2011-07-28 | Siemens Aktiengesellschaft, 80333 | Method for evaluating operating performance of bearing of computer tomography apparatus, involves evaluating measured circulation period of bearing and/or curve characteristic for evaluating operating performance of bearing |
Also Published As
| Publication number | Publication date |
|---|---|
| GB2150286B (en) | 1986-11-19 |
| GB8429382D0 (en) | 1985-01-03 |
| GB8331263D0 (en) | 1983-12-29 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |