The present invention relates to gripping devices for tubular elements such as the tubes on which yarn packages, often of substantial weight, are wrapped for delivery from a yarn manufacturer to a yarn user. More particularly, the apparatus of the present invention will enable a user, such as a worker, a robot or other mechanical device, to grip yarn tubes or other similar tubular elements where the interior diameter of the tube varies over a wide range and where the overall weight of the material mounted on the tube also varies considerably. In addition, the apparatus will grip both cylindrical and conical yarn tubes.
In the past, where manufacturers have had to employ articles such as yarn, wire or the like which are supplied from a manufacturer with the article wrapped for transportation and storage onto tubular supports, a number of employees have had to be assigned to the task of unloading and installing the individual packages on machines that utilize the material. Thus, the process of transporting and storing materials that are wrapped on tubular supports has been very labor intensive.
In the textile industry, the use of yarns wrapped on tubes has been a common practice for a large number of years. The handling by individual workers of individual packages has been one of the problems in reducing textile manufacturing costs as well as a source for a number of quality control difficulties. Specifically, in textile plants, the handling of yarns would often result in soiling of the exterior of the yarn packages. In addition, any accidents in connection with the packages, such as caused by collisions or dropping of individual packages often results in a total loss of the individual package so affected. To minimize such losses, mechanical devices have been developed to handle yarn packages with automatic control. However, effective yarn package gripping devices are required.
In a number of textile operations, in recent years, improvements in machine design have resulted in substantially increased production speeds. As a result, manufacturers have resorted to increasing the package size often to ponderous weight making it difficult or impossible for individual workers to manually handle the packages. For example, in present day false twist texturing machines which operate at linear speeds on the order of 600 to 800 yards/minute or more, a worker must place a tubular support yarn package on a yarn creel which holds a large number of such packages and which is placed adjacent to the machine. Such texturing machines are provided with a number of yarn texturing positions, each of which must be individually threaded. The yarn is passed through a position and is taken up on a take-up package as the yarn is processed. When the take-up package reaches its capacity, a worker must remove the take-up package and rethread the position from a supply package on the creel. Supply and take-up packages weighing 25 lbs. or even more are not uncommon so that worker fatigue can slow the production in a very short time.
Even without robotic systems, the present invention can greatly reduce this disadvantage by providing a mechanical tube gripping device which may be powered to assist in moving large tubular yarn packages and is particularly effective since the device can be utilized where the internal diameter of the tubes varies in size or even shape.
According to the present invention, a hollow shaft is provided which may be attached to any suitable support member. The support member may be a mechanical device such as a robot or an apparatus which can be easily manipulated by a worker. The shaft is provided with an actuating member which is slidably mounted on the interior of the hollow shaft. One end of the shaft is closed by a support plug and a plurality of linkage arms are connected between the actuating member and the support plug with each pair of linkage arms being pivotally connected and also pivotally connected to a gripping pad. A suitable drive member such as a piston and cylinder with an actuating rod extending from the piston to the actuating member in the shaft may be provided whereby, when the actuating member is moved toward the closed end, the linkage arms will move outwardly from the interior of the shaft through a slot in the wall thereof to move the gripping pads into firm engagement with the interior surface of a tube to securely grip the tube. Thereafter, the support base for the gripping device can be easily manipulated by a mechanical device or by a worker to move the yarn package from one position to another from storage to a textile machine and thereafter from the machine back to storage for packaging and transportation.
The apparatus of the present invention has the advantage over prior art devices in that the hollow shaft may be of small diameter, on the order of an inch, depending upon the weight of the load to be transported. This is achieved by disposing the actuating member such that it need not extend the length of the shaft thereby allowing the linkage arms to retract closer to the center of the shaft. Moreover, the apparatus may be adjusted very simply to accommodate other ranges of tube diameters by simply changing the lengths of the linkage arms and the rest or stop position of the actuating means.
The foregoing and other advantages will become apparent as consideration is given to the following detailed description taken in conjunction with the accompanying drawings, in which: