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.
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,
3. Multiple-bladder type leaf 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,
7. Pneumatic-mechanical shafts, and
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.
Referring to the drawings in detail wherein like elements are indicated by like numerals there is shown a pneumatic expanding core shaft 10 comprised of a hollow, cylindrical bearing tube 20 with one or more air bladders 30 contained within. The air bladder 30 has a pneumatic inflation valve 33 near a bladder end for inserting or releasing air into the bladder. Each air bladder 30 has an exterior surface 31 driving one or more lugs 40 loosely held and protruding through lug apertures 21 in the bearing tube 20. The lugs 40 engage the core 51 of a roll 50 of wound web material 52. In some configurations, the air bladder itself can engage the core without use of a separate lug. The shaft 10 has two ends 11 which 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 shaft 10.
Referring more particularly to
The sensor assembly 60 senses performance factors such as air pressure, temperature, and shaft rotation. Sensed data is stored in the sensor pre-processor 64 and then passed to the microprocessor 61 for transmittal to an external receiver 70. The external receiver 70 passes the signal with the data to a processor 71 wherein the data is stripped from the signal and processed into desired formats. The processor 71 may then pass processed data to a display 72 and/or industrial communication system 73. The receiver 70, processor 71 and display 72 can 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 repeater 74 would 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:
Referring more particularly to
Referring more particularly to
Referring more particularly to
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.
Applicants claim the priority benefits of U.S. Provisional Application No. 62/534,744, filed Jul. 2, 2017.
Number | Date | Country | |
---|---|---|---|
62534744 | Jul 2017 | US |