MXPA99001108A - Segmented screw traversing mechanism - Google Patents

Abstract

The linear traversing apparatus (10) includes a lead screw (12) formed from a plurality of lead screw segments (14, 16, 18) which are supportedat regular intervals, that is, at the intersection of adjacent lead screw segments, along a span by fixed hollow cylindrical splice points (20, 22). The lead screw segments (14, 16, 18) include external threading which engages the internal threading of a C-shaped spanning nut (28). The C-shaped spanning nut (28) has a circumferential portion removed so that the spanning nut (28) can clear the fixed hollow cylindrical splice points (20, 22) and associated support structure (24, 26) as the spanning nut (28) traverses the lead screw (12) in response to the rotation of the lead screw (12) and the inhibition of rotation of the spanning nut (28). The rotation of the spanning nut (28) is inhibited typically by mechanical communication with an instrument or other device which is engaged by a rail or a slot parallel to the longitudinal axis of rotation of the lead screw (12).

Description

MECHANISM OF DES IAZAMIFNrTY) ttrer-T.COIDAL SEGMENTADO ANTECEDENTS OF THE PTVENTION Field of the invention The present invention relates to a helical displacement mechanism which can be used to transport a bath, a sensor or other device through an extension, which is particularly useful in the manufacture of paper.

Description of the Previous Technique In the papermaking art, for example, the baths are used to rewet the paper web or to clean and condition the fabric or the wire after the sheet has passed over or to clean rollers or molds during functioning. Such baths typically extend in the transverse direction of the machine of the machine above the fabric or the rollers, to carry out this purpose. A device of this nature is described in U.S. Patent No. 4,701,242, issued October 20, 1987. This device involves the use of a bath head mechanism which is supported by a housing having a track and a trailer. which displaces the network. A toilet is placed on the trailer with its regulated movement and position. Other mechanism to move a bath or bath through a network involves the use of oscillating arrangements of sphere and screw through which the bath is supported and its movement is regulated. An example of this is found in U.S. Patent No. 4,598,238 issued July 1, 1986. Although these devices prove to be satisfactory, it is desirable to provide a more simplified mechanism for supporting and moving the bath. This is especially valid in situations where the bathroom goes through a long extension. It is also desirable to have such a device which allows for the formation of points in the network as desired.

OBJECTIVES AND BRIEF DESCRIPTION OF THE INVENTION Therefore, a main objective of the invention is to provide a helical displacement mechanism which is relatively simple and reliable. A further objective is to provide such a mechanism which supports and controls the movement of the bath through a fabric, wire or mesh used in papermaking.

It is an additional objective to provide such a mechanism with a multitude of applications to support desired devices through extensions that include extended extensions, typically involved in papermaking. In accordance with this invention, a segmented helical assembly is provided to provide a simple yet effective means for allowing displacement of a distance through the elements of the paper machine and the like. In this regard, the screw comprises a series of segments coupled together. The segments are supported by support members placed along their entire length. The support does not interfere with the rotation of the screw segments. A displaceable "C" nut is placed on the screw and travels axially along the screw as it rotates. The displacement network is configured so as to move freely through the segments and support members. Since the displaceable nut can be mounted with a bath or other device and move transversely in the length of the extension.

BRIEF DESCRIPTION OF THE DRAWINGS By means of the present invention, its objectives and advantages are obtained, the description of which must be taken together with the drawings, wherein: Figure 1 is a partially exploded perspective view of the segmented helical scroll mechanism having a housing and a bath shown in dashed lines; Figures 2A and 2B illustrate helical adaptation of successive segments and the coupling thereof with each other; Figure 3 is a perspective view of a tubular beam which encloses a series of helical segments which are used to move a scanning instrument; Figure 4 is a front perspective view of an alternative embodiment of the present invention for a more robust torque transmission; and Figures 5A and 5B are plan views, partially in perspective, of the details of the joining of the helical segments of the embodiment of Figure 4.

DESCRIPTION DETAT.T.an? D THE PREFERRED MODALITY Referring now to the drawings in detail, where similar numbers refer to similar elements throughout the various views, it is noted that Figures 1 and 4 are partially broken away perspective views of the helical scroll mechanism 10 of the present invention. The helical displacement mechanism 10 includes an externally threaded, segmented guide screw 12, which is comprised of guide screw segments 14, 16, 18. Although three guide screw segments 14, 16, 18 are illustrated, the externally threaded, segmented guide screw 12 can be extended indefinitely with successive guide screw segments. The externally segmented threaded guide screw 12 is articulated for rotation within the fixed hollow cylindrical junction points 20, 22, which, in turn, are fixed and supported by the blocks 24, 26. The displaceable nut 28 is a cylinder partially internally threaded, hollow, with a portion of its circumference removed so that it forms a cross section of type "C". The displaceable nut 28 is additionally fixed, for example, to a bath head 30 (or similar apparatus) which in turn is coupled by the groove 32 formed parallel to the longitudinal or rotational axis of the externally threaded, segmented guide screw 12. The internal threading of the displaceable nut 28 engages the external threading of the externally threaded, segmented guide screw 12. As the coupling of the bath head 30 into the slot 32 prevents rotation of the displaceable nut 28, the rotation of the externally threaded segmented guide screw 12 will cause the displaceable nut 28 to axially traverse the externally threaded, segmented guide screw 12. Other means to prevent the rotational movement of the displaceable nut 28 to allow axial movement thereof along the guide screw 12 and any device which is coupled thereto whose movement is regulated, will be readily apparent to those familiar with the technique. For example, a trailer that supports a bath and that is located on a track with the displaceable nut 28 coupled to the trailer, is a possibility. A flexible pipe or other necessary connections may be attached to the bath or other device to provide water, air or any other means required. The "C" type cross section of the displaceable nut 28 allows the displaceable nut 28, during travel of the externally threaded guide screw 12, to pass through the blocks 24, 26, which support the fixed hollow cylindrical splice points 20, 22. . As shown in more detail in Figures 2A and 2B, the guide screw segments 14, 16 (and likewise the number 18 and any successive guide screw segments) include externally threaded cylindrical portions 34, 36, respectively. The guide screw segments 14, 16 also include axially extending semi-cylindrical flanges 38, 40, respectively, with a central axis coinciding with the rotational axis of the guide screw segments 14, 16. Semi-cylindrical flanges 38, 40 also include inwardly facing faces 42, 44 (see also Fig. 1) through which the rotational axes of the segments 14, 16 of the guide screws pass. This allows the flat faces 42, 44 facing inward of the semi-cylindrical flanges 38, 40 of the adjacent guide screw segments 14, 16 to engage with each other, as shown in Figure 2B. As shown in Figures 1, 2A and 2B, the cylindrical flanges 38, 40 further include internally threaded, radially oriented openings 43, 45 (the opening 43 is countersunk) which allows the bolt 46 to hold the flanges 38, 40 together . As can be seen from Figure 1, the bolt 46 can be installed as it passes through the openings 48, 50 in the fixed hollow cylindrical splice points 20, 22 and is threaded downwards to ensure the engagement of the segments 14, 16 guide screw. This configuration allows the rotation of a single threaded screw segment from a source of external rotational movement, such as a motor (see element 60 in FIG. 3), to communicate mechanically with a plurality of sequential screw screw segments which form the screw 12 guide externally threaded, segmented. Externally segmented, extremely long threaded guide screws can be formed without significant bending to the extent that the guide screw 12 is supported by fixed hollow cylindrical joints 20, 22 at regular intervals. The axial length of the semi-cylindrical flanges 38, 40 together with the orientation of the threads of the externally threaded cylindrical portions 34, 36 are spaced apart so that, in the configuration shown in Fig. 2B, the threads of the outer cylindrical portion 34 are "in phase" with the threads of the external cylindrical portion 36 so that a continuous tapping step is obtained between adjacent guide screw segments. That is, the distance measured axially between the respective portions of the threads of adjacent guide screw segments is equal to an integral multiple of the distance between the respective successive thread portions 5 in a single guide screw segment. This allows regular axial displacement of the displaceable nut 28 with little or no thread bore of the threads as the movable nut 28 traverses between adjacent guide screw segments in response to the rotation of the segments 14, 16, 18 of the screws 12 guide internally threaded, segmented. As shown in Figure 1, the semi-cylindrical flanges 38, 40 contact the washer-type sleeves 52, 54 within fixed hollow cylindrical splice points (illustrated only with number 20) to facilitate the rotation of the guide screw segments 14, 16, 18 which comprise the externally segmented threaded guide screw 12. Figure 3 is an illustration of the scroll mechanism 10 of the present invention with one end of the externally threaded guide screw 12 engaged by the source 60 of external rotational movement and the displaceable nut 28 that moves through the tubular beam enclosure 62. The instrument 64 is mounted on slots 68 which contact the axial rail 66 in the enclosure 62 of the tubular beam. The movement of the nut 28 displaceable in response to the The rotation of the externally threaded guide screw 12 mechanically drives the instrument 64 such as a sensor which traverses the outside of the enclosure 62 of the tubular beam. The open circumferential portion of the displaceable nut 28 is oriented upwardly so as to accommodate the mechanical support structure for externally threaded guide screw 12 (similar to fixed hollow cylindrical splice points 20, and blocks 24, 26 of Figures 1, 2A and 2B). To use the scroll mechanism 10 of the present invention, the blocks 24, 26, with the 0 hollow cylindrical splice points 20, 22 are fixed to • appropriate intervals through the extension, for example above the paper web. The guide screw segments 14, 16, 18, together with the washer-type sleeves 52, 54 are installed within the hollow cylindrical splice points 20, 22 and are held together by bolts 46 which pass through the openings 48. , 50 and are fixed within the openings 43, 45 so as to engage the flat faces 42, 44 oriented inwardly of the semi-cylindrical flanges 38, 40 of the front screw segments. The internal threads of the displaceable nut 28 engage the external threads of the front screw segments 14, 16, 18 when one end of one of the front screw segments is free, either before or after the screw segments front join together. The displaceable nut 28 is fixed to the bath head 30 which contacts a groove 32, as shown in Fig. 1, or a joint, as shown in Fig. 3, where the movable nut 28 is fixed to the instrument or sensor 64 by means of a discharge leg or articulation through the enclosure 62 which prevents the rotation of the displaceable nut 28 and at the same time allows the axial movement of the instrument or sensor 64 as the guide screw 12 rotates. It is important that the displaceable nut 28 does not rotate in unison with the externally threaded guide screw 12 and that the displaceable nut 28 is oriented so that its open circumferential portion is free with the points 20, 22 of fixed hollow cylindrical joints and the blocks 24. , 26 as the displaceable nut 28 traverses axially threaded screw 12 externally. Externally threaded guide screw 12 is attached to a source of external rotational movement, such as number 60 in Figure 3. This source of rotational motion typically has a controlled rotational speed and a total cumulative rotational displacement in order to monitor and control with precision the linear speed and displacement of the displaceable nut 28 and associated devices such as the bath head 30 (figure 1) or the instrument 64 (figure 3). Figures 4, 5A and 5B illustrate an alternative embodiment of the scroll mechanism 10. The guide screw segments 14, 16 include semi-cylindrical cavities 72, 70, respectively, coaxial with flanges 38., 40 semi-cylindrical. The semi-cylindrical flanges 38, 40 of the guide screw segments 14, 16 form male elements which coincide with the corresponding females formed by the semi-cylindrical cavities 70, 72, respectively, of the adjacent guide screw segment (14, 16, respectively). The cavities 70, 72 prevent the segment ends from contacting the adjacent segment ends. The rigidity of the joint is thus provided by tangential stress of the cavity instead of tension in the screw of the center of the joint or bolt 46, and therefore the resulting rigidity is much greater. Therefore, several of the objectives and advantages mentioned above have been effectively obtained. Although the preferred embodiments of the invention have been shown and described in detail herein, it is to be understood that this invention is not limited in any way by the same and that its scope should be determined by that defined in the appended claims.

Claims (12)

1. A linear displacement apparatus, characterized in that it comprises: a guide screw along a longitudinal axis of rotation, at least a portion of the guide screw is threaded; the guide screw is formed of a plurality of externally threaded guide screw segments; the axial ends of the externally threaded guide screw segments include flanges which engage flanges of externally adjacent, externally threaded guide screw segments by a means preventing axial movement therebetween; an axial length of the flanges is chosen to maintain a continuous tapping step between adjacent segments of guide screw; the ridges are semi-cylindrical with a substantially planar face along which the longitudinal axis of rotation of the guide screw passes; the respective flat faces of the adjacent guide screw segments are placed against each other and rotationally held by a plurality of fixed support devices engaging with the guide screw along an extension of the guide screw, the respective flat faces allow at least one of the guide screw segments to be separately inserted into or removed from the corresponding support device without requiring insertion or removal of an adjacent guide screw segment from the corresponding support device; the support devices include hollow cylindrical portions in which the flanges are inserted to rotationally maintain the respective planar faces of adjacent screw segments therein so as to provide rigidity and a substantially hermetic coupling therebetween which provides a torsional force that it is transported between the adjacent guide screw segments; and a displaceable nut with threads engaging a portion of a circumference of the guide screw, the portion of the circumference is dimensioned to allow the displaceable nut to axially traverse the threaded guide screw free of obstruction by the support devices in response to rotation of the Guide screw in combination with the inhibition of rotation of the displaceable nut.

2. The linear displacement apparatus according to claim 1, characterized in that the plurality of support devices are coupled to the guide screw along portions of the guide screw which are free of threading.

3. The linear displacement apparatus according to claim 2, characterized in that the hollow cylindrical portions are engaged with the guide screw along the portions of the guide screw which are free of threading.

4. The linear displacement apparatus according to claim 3, characterized in that the guide screw is formed of a plurality of externally threaded screw segments.

5. The linear displacement apparatus according to claim 4, characterized in that the axial ends of the externally threaded guide screw segments include flanges which are joined to the flanges of the axially adjacent externally threaded guide screw segments.

6. The linear displacement apparatus according to claim 5, characterized in that the axial length of the flanges is chosen such that a continuous tapping step is maintained between adjacent guide screw segments.

7. The linear displacement apparatus according to claim 6, characterized in that the ridges are semi-cylindrical with a flat face facing inward, through which the longitudinal axis of rotation of the guide screw passes.

8. The linear displacement apparatus according to claim 3, characterized in that the coupling means further includes respective radially oriented openings in the shoulders which are aligned and a nut that holds the flanges of the adjacent guide screw segments together and thus generates the portions of the guide screw which are free of threading.

9. The linear displacement apparatus according to claim 8, characterized in that it also includes means for inhibiting the rotation of the displaceable nut.

10. The linear displacement apparatus according to claim 7, characterized in that the semi-cylindrical flanges coincide with semi-cylindrical openings in the adjacent guide screw segments.

11. The linear displacement apparatus according to claim 10, characterized in that the semi-cylindrical flanges are coaxial with semi-cylindrical openings.

12. The linear displacement apparatus according to claim 8, characterized in that the coupling means further includes an opening in the hollow cylindrical portion of the support device that allows the bolt to pass therethrough.