Measuring and testing – Dynamometers – Responsive to force
Reexamination Certificate
1999-11-18
2001-05-01
Noori, Max (Department: 2855)
Measuring and testing
Dynamometers
Responsive to force
C073S862392, C073S829000, C019S105000
Reexamination Certificate
active
06223609
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to an apparatus for measuring the thickness and/or irregularities of a running sliver in a spinning preparation machine, particularly a draw frame. The apparatus is of the type which has a biased sensor element which mechanically scans (contacts) the sliver and a tongue-and-groove roll pair which defines a closed nip of generally rectangular cross section through which the sliver passes. The groove roll of the roll pair has a radially fixed rotary axis.
Published PCT Application WO-A-91 16595 discloses an apparatus for guiding the slivers at the inlet end of the drawing unit of a draw frame. The apparatus includes a conically converging sheet metal support body having laterally upwardly bent wall faces and, downstream thereof (as viewed in the direction of sliver advance), a sliver guide having a rectangular inlet cross section, parallel-extending top and bottom walls and converging, upstanding lateral walls. The side-by-side arranged slivers glide on the supporting surface formed of the supporting body and the bottom wall of the sliver guide. Between the slivers and the side walls an intermediate space is provided at the sliver intake zone. The sliver guide is situated immediately in front of a pull-off roll pair whose parallel axes are vertically oriented. The roll pair also serves for measuring the sliver thickness within a predetermined tolerance range and, for such a purpose, the distance between the two cooperating rolls of the roll pair is variable. The radially movable, spring-loaded roll forms a biased, movable sensor element and is horizontally displaceable relative to the stationary roll. The stationary roll is a “groove roll” and is composed of a middle disk and two flanking disks. The middle disk has a smaller diameter than the two flanking disks whereby the circumferential peripheral face of the roll forms a circumferential groove. The radially movable roll is a “tongue roll” and is formed of a single disk which projects, with a peripheral portion, into the groove of the groove roll. The circumferential surface of the middle disk of the groove roll forms a rotary, radially stationary counterface for the circumferential surface of the radially movable tongue roll. By means of the tongue-and-groove construction an essentially rectangular constriction (nip) is formed between which a sliver bundle formed of a plurality of slivers passes in a compressed state for measuring purposes. In operation, the individual slivers run into the sliver guide at the drawing unit inlet with a speed of, for example, 150 m/min. The converging walls of the sliver guide gather the slivers without any clamping into a single plane so that they assume a side-by-side relationship. The slivers exiting the sliver guide are first densified by being pulled into the nip of the two downstream arranged rolls, that is, they are compressed to their solid material cross section and thus, in particular, enclosed air is expelled therefrom so that a measurement may take place. The circumferential speed of the rolls and the running speed of the slivers are identical so that no slippage takes place between the rolls, on the one hand, and the slivers, on the other hand. The clamping effect of the rolls required for exerting a pulling force is simultaneously used for the densification needed for the measuring step. After the slivers exit the roll nip they diverge laterally and enter the downstream-arranged drawing unit.
It is a disadvantage of the above-outlined apparatus that it involves substantial structural and operational outlay. It is a particular drawback that the drive of the two rolls is structurally complex and also, that a rotary drive has to be used for the radially displaceable roll. It is a further disadvantage that both rolls have to be driven. The drive for the radially movable roll includes a spur gear pair; one of the gears is mounted on the shaft of the roll while the other gear is arranged coaxially with the pivot axis of the pivotal arm carrying the radially displaceable roll. This arrangement ensures that the meshing relationship of the gears of the gear pair remains unchanged independently of a pivotal motion of the pivot arm. To obtain the required, opposite rotation of the rolls, a further, intermediate gear has to be provided which has the additional disadvantage that, apart from its complex structure, clearances between the individual gear teeth lead to accumulated inaccuracies.
SUMMARY OF THE INVENTION
It is an object of the invention to provide an improved apparatus of the above-outlined type from which the earlier-described disadvantages are eliminated, which is structurally particularly simple and which makes possible an improved measurement of the running sliver.
This object and others to become apparent as the specification progresses, are accomplished by the invention, according to which, briefly stated, the apparatus for advancing a sliver and sensing thickness variations thereof in a fiber processing machine includes a tongue-and-groove roll pair composed of a tongue roll and a groove roll. The groove roll is radially fixedly supported and has a circumferentially extending groove including a groove bottom. The tongue roll projects into the groove and defines, with the groove roll, a nip through which the sliver passes for being compressed and advanced by the tongue-and-groove roll pair. The apparatus further has a sensing device including a biased, movably supported sensor element projecting into the groove of the groove roll and cooperating with the groove bottom upstream of the nip as viewed in a direction of sliver advance for pressing the sliver against the groove bottom and for undergoing excursions in response to thickness variations of the sliver passing between the sensor element and the groove bottom.
According to the invention, for the measuring process the groove bottom of the groove roll is used as a counter supporting element which cooperates with the sensor element. The apparatus according to the invention ensures that the slivers are densified and scanned by the sensor element upstream of the nip defined by the tongue-and-groove roll pair (pull-off rolls), so that the latter merely needs to pull through the earlier-sensed running sliver. These measures permit a separation of function by providing that the sensor element arranged upstream of the pull-off rolls simultaneously densifies and scans the running sliver in a simple manner. The after-connected pull-off rolls may be of simplified structure and, as far as their installation is concerned, may be significantly simpler since they function exclusively as a pulling mechanism. Particularly by eliminating the measuring function of the pull-off roll pair, the significant difficulties and complexities experienced in the measuring process performed by the conventional apparatus are avoided. Thus, the slivers are submitted to a separate handling as concerns a densification which is required for the mechanical scanning step and a densification required for the sliver-advancing (sliver-pulling) step. Accordingly, the apparatus according to the invention provides an improved measuring of the sliver bundle at the inlet of the drawing unit and further, the side walls of the groove roller ensure that the lateral guidance and support of the slivers is preserved.
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Corrales Pedro
Leifeld Ferdinand
Kelemen Gabor J.
Noori Max
Trutzschler GmbH & Co. KG
Venable
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