Monitoring system for pneumatic core shafts and shaft adapters

A monitoring system for pneumatic shafts and pneumatic shaft adapters. A sensor assembly is physically joined in operative engagement with the bladders of pneumatic shafts and adapters. Sensed data is wirelessly transmitted to a remote receiver for processing and display.

BACKGROUND OF THE INVENTION

This invention relates to pneumatic core shafts and pneumatic shaft adapters, and in particular, to a system for directly monitoring operating criteria for pneumatic core shafts and pneumatic shaft adapters.

Pneumatic core shafts are expanding shafts for gripping and holding a core of a wound material roll. The shaft transmits torque to the roll of material from a motor, clutch or brake thereby winding, unwinding or stopping rotation of the core. The core shaft then engages and is driven by machine. The wound material can be any flexible web, e.g., paper, film, foil, nonwovens, and the like.

Pneumatic core shafts generally have a central air bladder or multiple air bladders within a bearing tube. Inflating the air bladder or bladders force attached lugs through openings in the bearing tube. A typical bladder will be pressurized to 80 psi. The lugs grip and hold the internal surface of the core of a web material roll. Lugs may have different shapes, such as ovals, buttons, strips, leafs, and spirals, Some pneumatic core shafts have multiple bladders such as with strip and leaf lugs,

Pneumatic shaft adapters typically enable the use of small diameter shafts with a larger diameter cores. One type of pneumatic shaft adapter has an external bladder, wherein the bladder expands to engage directly with the interior of a core. This same technology would be used on shaft adapters with a hollow central bore which slide over the outer diameter of another shaft to adapt from a smaller core size to a larger core size.

If air pressure in a core shaft or shaft adapter air bladder is lost during operation, the core can slip on the shaft or adapter, and torque is no longer transmitted from the motor, clutch or brake. This causes tension loss in the running web and results in process defects. Core slip can also damage the inside of the core so that a partially wound roll of material is no longer usable.

There is, therefore, a need to monitor air pressure in the shaft air bladder or pneumatic shaft adapter bladder to ensure no slipping is occurring. This is challenging due to the rotating nature of the shaft and core. Rotary unions are possible, but require complex pneumatic connections. There is also an advantage to automatically providing an alarm signal to a parent machine while running if a leak occurs. There is also an advantage to automatically providing a “ready to run” signal during air shaft or adapter inflation. With existing technologies, if an operator forgets to inflate, or only partially inflates, an unwind or rewind shaft, and then starts the machine, web material breaks are probable resulting in costly scrap as well as lost time to repair the operation. With larger shafts, the time to fill an air bladder to proper pressure may be up to ten minutes. An operator may believe a particular shaft or adapter is properly inflated, when it is actually underinflated. This leads to slippage and core damage.

Often times a slow leak in the bladder occurs before a large scale blow out. Detecting and alerting operators to a slow leak can prevent slippage and process mishaps. A slow leak is also indicative that maintenance needs to be performed on the shaft.

It is known to have variable air pressure inside a rewind shaft bladder. However, the air pressure sensing mechanisms is always located external to the shaft as part of the air supply line or integrated in an external air pressure transducer. These types of shafts are called “friction shafts” or “slip shafts” or “differential rewind shafts” and all require a constant air pressure connection be made through a rotary union to the shaft from a parent machine while the shaft is in operation.

SUMMARY OF THE INVENTION

The present invention overcomes the disadvantages of prior art pneumatic expanding shafts and shaft adapters with integrated sensors by providing wireless air pressure sensor technology to additional expanding shaft and shaft adapter designs. Firstly is to a multiple bladder shaft design where multiple bladders are connected by one air manifold. Secondly is an external bladder style shaft adapter which uses no separate clamping elements, i.e., the bladder makes direct contact with the core. Thirdly, in the case of single central shaft bladder designs, the sensor connects on an opposite journal side of the shaft to a secondary air manifold. The sensor is physically seated in a cavity formed in the bearing tube or adapter end cap or adapter flange ring. If the sensor cavity is located on the same journal as the cavity for the inflation valve, the total strength of the journal is reduced. It is, therefore, an advantage to having the sensor located on the opposite side journal. The sensor measures actual air pressure within the air bladder or air piston and transmits sensed measurements to a nearby receiver where the sensed data is passed to an appropriate processor. The invention sensor operates whether or not the shaft is turning. By seating the sensor within a cavity, the sensor is protected from the web core. The sensor cavity is preferably located near one or more shaft ends so that transmission is not interfered with by the core or web material wound on the core. The sensor is separate and independent from the bladder air supply line.

Current battery powered sensors provide limits on the rate of data transmitted as each transmission drains the battery further. Sensors in the present invention are optionally powered using battery-less energy harvesting methods providing transmission of more complete data with an improved sample rate for faster response times. Energy harvesting uses piezoelectric or similar technology which takes the mechanical rotational and vibrational energy of the shaft and converts it to low power electrical energy with enough power to energize the wireless sensor assembly. In applications that use batteries it is advantageous for the battery itself to be end-user replaceable so customers do not need to repeatedly purchase complete sensor assemblies and then repairing them with the shafts and control devices.

Factories with high quality control requirements use supervisor control and date acquisition (SCADA) technology or other industrial communications systems to monitor run parameters for all aspects of their machines. The invention sensor output can easily be incorporated into a factory's industrial communications system.

Some pneumatic bladders require certain operating temperature ranges to hold air pressure. There is also often a need to monitor shaft temperature and provide an alarm output if a maximum or minimum temperature has been exceeded. The invention sensor contains temperature sensing means as well as air pressure sensing means.

There is an advantage to actively monitoring a shaft rotation, i.e., when it is rotating or not rotating. Furthermore, multiple shafts are often used on one unwind/rewind of a web handling machine. There is an advantage to knowing the total run time on any given shaft for preventative maintenance purposes. There is also an advantage to quickly identifying which shaft(s) is (are) being run on a machine. Rotation of a pneumatic core shaft or adapter is measurable through the invention sensor by the addition of an accelerometer to the invention sensor.

The present invention is used with any pneumatic expanding shaft or pneumatic shaft adapter in which air pressure is used to create friction against the inside of a winding core for gripping, including but not limited to:

1. Central bladder type lug shafts,

2. Central bladder type button shafts,

4. Multiple bladder external element type strip shafts and core adaptors,

5. Spiral external element type expanding shafts,

6. External bladder type shaft adapters,

8. Shafts using mechanical type expansion and pneumatic type retraction.

The invention sensor has a plurality of sensor means and has the ability to transmit sensed data, including a sensor identification code. The invention sensor may also sense battery voltage level, air pressure, temperature and rotational acceleration.

The invention sensor is mounted below the outer diameter surface of the shaft or adapter in such a way that the sensor can transmit wireless signals and also avoid interference with sliding a winding core onto and off of the shaft when a web roll is being loaded or unloaded.

These together with other objects of the invention, along with various features of novelty which characterize the invention, are pointed out with particularity in the disclosure annexed hereto and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and the specific objects attained by its uses, reference should be made to the accompanying drawings and descriptive matter in which there is illustrated a preferred embodiment of the invention.

DETAILED DESCRIPTION OF INVENTION

Referring to the drawings in detail wherein like elements are indicated by like numerals there is shown a pneumatic expanding core shaft10comprised of a hollow, cylindrical bearing tube20with one or more air bladders30contained within. The air bladder30has a pneumatic inflation valve33near a bladder end for inserting or releasing air into the bladder. Each air bladder30has an exterior surface31driving one or more lugs40loosely held and protruding through lug apertures21in the bearing tube20. The lugs40engage the core51of a roll50of wound web material52. In some configurations, the air bladder itself can engage the core without use of a separate lug. The shaft10has two ends11which may be journaled into a machine, engaged with two safety chucks, or engaged by a cam-follower type bearing, or other drive coupling method. As is expounded further below, with shaft adapter configurations, there is a hollow central bore, wherein the adapter slides over a smaller diameter shaft10.

Referring more particularly toFIGS. 1-4, 10-11 and 18, there is shown a pneumatic core shaft10with a single air bladder30contained within a cylindrical bearing tube20. The shaft bearing tube20has a sensor aperture22formed therein providing an opening to the air bladder30. A sensor assembly60is seated within the bearing tube sensor aperture22and joined in operative engagement with an air bladder interior32. The sensor assembly60is generally positioned at a bladder end opposite to the inflation valve33. Each sensor assembly60is comprised of one or more transducers63, a sensor pre-processor64, a microprocessor61, a wireless transmitter62and antenna68. Preferably, the transducers are comprised of an air pressure sensor65, acceleration sensor66and temperature sensor67. The sensor assembly may have a battery69to provide power or the sensor assembly may be powered through battery-less energy harvesting means. In either case, it would be desirable to also include power level sensing means within the sensor assembly.

The sensor assembly60senses performance factors such as air pressure, temperature, and shaft rotation. Sensed data is stored in the sensor pre-processor64and then passed to the microprocessor61for transmittal to an external receiver70. The external receiver70passes the signal with the data to a processor71wherein the data is stripped from the signal and processed into desired formats. The processor71may then pass processed data to a display72and/or industrial communication system73. The receiver70, processor71and display72can all be integrated into an existing tablet or smart phone unit. Where the sensor assembly transmitted signal must transmit over a large area or is subject to interference from various sources, a repeater74would be positioned near to the sensor assembly to provide means for boosting power within the signal. The transmitted signal can be any wireless signal including, but not limited to, RF, Bluetooth, induction wireless, UWB, ZigBee, or other.

The processor and display functions may provide the following control and monitoring features:1. Visual/audible/digital signal alarms when air bladder pressure is outside preprogrammed minimum and maximum limits;2. Visual/audible/digital signal alarms when temperature is outside preprogrammed minimum and maximum limits;3. Internal logic to determine when a shaft has been inflated.4. Resettable counter for number of inflations for a specific shaft;5. Timer to determine total time a shaft has been inflated;6. Visual/audible/digital signal alarm to indicate a preset inflation value has been reached;7. Operating lock until a preset inflation has been reached;8. Visual/audible/digital signal alarm indicating a bladder slow leak;9. Visual/audible/digital signal alarm output indicating a low battery level for sensors with batteries;10. Visual/audible/digital indicators when shaft starts and stops rotating;11. Counter/timer determining number and/or time shaft has been rotating;12. Visual/audible/digital indicator of shaft RPM; and13. Visual/audible/digital signal alarms when shaft RPM is outside programmed ranges.

Referring more particularly toFIGS. 5-9, 10-11 and 18, there is shown a pneumatic core shaft10with multiple air bladders30contained within a cylindrical bearing tube20. An air manifold34is provided near to both shaft ends11for distributing air to the air bladders30. The air manifold34has a pneumatic inflation valve33near a core shaft end11for inserting or releasing air into the bladders. The air bladders30are positioned within longitudinal channels23formed within the bearing tube outer surface. Strip lugs40are loosely attached to the bearing tube channels23above the air bladders30. Inflation of the bladders through the inflation valve33expands the bladders and forces the strip lugs radially outward for enhanced gripping of a web core. The strip lug40can either be in the shown configuration, or as a leaf-type lug (not shown). The shaft bearing tube20has a sensor aperture22formed therein providing an opening to an air manifold34. A sensor assembly60is seated within the bearing tube sensor aperture22and joined in operative engagement with an air manifold interior34. The sensor assembly60is generally positioned at a shaft end11opposite to the inflation valve33, but could also be positioned on the same shaft end as the inflation valve33. Operation of the sensor assembly60is as described above.

Referring more particularly toFIGS. 10-11, 12, 13 and 18, there is shown an external bladder type shaft adapter80. This type of shaft adapter is generally mounted onto a steel bar or as a shaft adapter so a 3″ shaft can grip a 6″ or larger core. The principles of the invention are the same whether or not the pneumatic air bladder is with a core shaft or shaft adapter. The advantages of monitoring attributes of the bladder, such as air pressure, temperature and motion are the same. As shown, the external bladder shaft adapter80is comprised of left and right modules85each having a hollow bore84, two end caps82and a clamp collar83for attachment to a shaft (not shown). Each external bladder adapter module85has an air bladder30about the adapter module main body81. The bladder is made from a semi-rigid polyurethane material, or similar, and its exterior surface31expands radially about the adapter to make direct contact with a core (not shown). The bladder interior32receives air through an inflation valve33mounted on one side of the adapter parallel to the adapter longitudinal axis. A sensor assembly60is attached to the bladder30on the other side of the adapter parallel to the adapter longitudinal axis. The sensor assembly transmits sensed data as described above. The air bladders30for the modules may be interconnected by a pneumatic hose86.

Referring more particularly toFIGS. 10, 11, 14-17, and 15, there is shown a strip style shaft adapter90. As with the bladder adapter, a strip adapter is generally mounted onto a steel bar or as a shaft adapter so a small diameter shaft can grip a larger core. The strip adapter90is comprised of a left and right module97, each comprised of a hollow, generally cylindrical bearing tube91with a hollow bore95and having a plurality of longitudinal channels92formed therein. Each channel has an air bladder30driving a corresponding strip lug40for engagement with a core (not shown). The air bladders30are interconnected by means of an air manifold34which in turn is inflated through a pneumatic inflation valve33. The air manifolds for each module97may be interconnected by means of a pneumatic hose98. The strip adapter have end caps93and clamp collars94for attachment to a shaft. A sensor assembly60is attached to one end of the adapter90and is interconnected to the air manifold by means of a pneumatic sensor connection96. The sensor assembly60transmits sensed data as described above.

It is understood that the above-described embodiments are merely illustrative of the application. Other embodiments may be readily devised by those skilled in the art, which will embody the principles of the invention and fail within the spirit and scope thereof.