Device for rotating a mattress on the working table of a hemming machine

Abstract: Device for turning a mattress (4) on a working table of a hemming machine (7), comprising a vertically hinged structure (14) supported by a fixed frame (1,12) above the working table and rotatable about a vertical axis (C) that passes at the stitching region of the hemming machine; a pusher (31,32) guided vertically on the vertically hinged structure; means (33,34) for moving the pusher between a raised disengagement position and a lowered one, at which the pusher laterally engages the mattress; and means (20-23) for rotating the vertically hinged structure between two positions angularly offset by 90 o .

Description: The present invention relates to a device for rotating a mattress on the working table of a hemming machine. It is known that it is necessary to rotate by an angle of 90° a mattress on the working and transport table of a hemming machine in order to perform operations at the corners in passing from the hemming of the transverse sides to the hemming of the longitudinal sides. In hemming machines provided with a stationary sewing machine, the mattress is currently rotated mostly by hand. Hemming machines have also been proposed which comprise devices for rotating the mattress with respect to the sewing machine. Devices of this kind are known from European patent application publication no. 264618 in the name of the same Applicant, from European patent no. 330.285, from German patent application publication no. 3521559, and from French patent no. 1,567,893. In known devices, the mattress slides on a table during rotation, and therefore friction forces arise which make the rotation angle inaccurate. Known devices furthermore do not solve the problem of turning over the mattress in order to perform the hem on the other side. The technical aim of the present invention is to provide a device that allows to obviate these drawbacks, so that the orientation of the mattress with respect to a hemming machine becomes accurate and so as to mechanize the mattress turning-over operations, which are currently performed by hand by the same operator who controls the hemming machine, with great effort and waste of time. Within the scope of this aim, an object of the present invention is to provide a device that is reliable in operation and versatile in use in relation to the various shapes and dimensions of the mattresses. This aim and this object are achieved with a device whose characteristics are defined in the claims. Further characteristics of the present invention will become apparent from the following description on the basis of the accompanying drawings, wherein: figure 1 is a perspective view of the device, applied to a mattress hemming machine; figures 2 and 3 are perspective views of the device, taken from a different viewing angle, with the pusher in raised and lowered position respectively; figure 4 is a plan view of a variation of the device; and figure 5 is a lateral elevation view of the variation of figure 4. With reference to figures 1 to 3, the device comprises a frame composed of a post 1 having a square cross-section and rising to the side of a transport and working table 2 constituted by rows of mutually parallel free rollers 3. The rollers 3 are very close to each other but are not in mutual contact, so that they can rotate freely in both directions A and B and allow the handling of a mattress 4 placed thereon. A carriage 5 can be positioned on the post 1, and a bracket 6 cantilevers out from said carriage and supports a hemming machine 7 comprising a conventional sewing machine equipped with means for guiding a tape that is meant to be stitched so as to cover the stitch lines joining the upper and lower faces 8 and 9 of the mattress 4 to the perimetric band 10. The inclination of the bracket 6 is adjustable to allow to orientate the hemming machine 7 at an angle allowing diagonal stitching suitable to form a rounded ridge 11 surrounding the upper and lower faces of the mattress. An arm 12 protrudes from the top of the post 1 and supports, at its end, a sleeve 13 the axis C of which is vertical and passes at the region where the hemming machine forms its stitch. A substantially bracket-like vertically hinged structure 14 is rotatably supported in the sleeve 13 and is composed of an upright 15, rigidly coupled, by means of two arms 16 and 17, to a pivot which is rotatable within the sleeve 13, and of a beam 18 that cantilevers out from the lower end of the upright 15 and is supported by a brace 19 that joins the beam 18 to the top of the upright 15. A pivot 20 is furthermore mounted at the top of the upright so that it can rotate about a vertical axis; a diametrical female thread 21 is formed in said pivot and is engaged by a threaded rod 22. The threaded rod 22 is driven by a motor 23 installed on a platform 24 that is laterally rigidly coupled to the arm 13. The actuation of the threaded rod 22 in one direction or the other, owing to the off-centered position of the pivot 20 on which the rod 22 acts with respect to the axis C, accordingly produces the rotation of the structure 14 by an angle of substantially 90°. The structure 14 is completed by a rectangular frame 24a fixed to the beam 18 proximate to the upright 12 and at the front of which two pneumatic jacks 25 and 26 are applied vertically; the stems of said jacks protrude downward and support respective pads 27 and 28. Two guiding bushes for a pair of vertical parallel rods 29 and 30 are installed in the beam 18; said rods rise from a bar 31 that lies below the beam 18 and acts as a pusher to make the mattress 4 rotate about the axis C. A horizontal plate 32 protrudes from the upper edge of the bar 31 on the working table 2 and is meant to rest on the upper face of the mattress when the bar 31 is in the lowered condition and in abutment against a perimetric side, that is to say, in contact with the band 10. The bar 31 can be raised and lowered on the table 2 by means of a pair of jacks 33 and 34, in which the cylinders are mounted on the beam 18 and the stems are rigidly coupled to the bar 31. The described device is completed by a series of vertical rollers 35 freely mounted on the member 35a that delimits the working table 2 on the side of the hemming machine. The vertical rollers 35 form a vertical wall for guiding the mattress 8 during the hemming of its longitudinal and transverse sides. The device operates as follows. In order to hem the longitudinal and transverse sides of the mattress, the bar 31 is raised with respect to the working table 2 and is co-planar with respect to the vertical rollers 35. The mattress 4, after being transferred onto the rollers 3 of the table 2, is positioned so that its side to be hemmed (for example the transverse one, as in figure 2) abuts against the rollers 35, and is then made to advance in the direction A through the hemming machine 6 to form the hem along the corner formed by the band 10 with respect to the upper face. When the trailing corner of the mattress is located at the axis C, the jacks 25 and 26 are activated and, by descending, lock the mattress 4 on the roller table 2. At the same time, the jacks 33 and 34 are actuated so as to move the bar 31 into a position that is adjacent to the band 10 of the freshly hemmed side and so as to make the plate 32 rest on the upper face of the mattress. It should be noted that the height of the bar 31 and of the rollers 35 is such as to prevent mutual contacts when the bar 31 is in lowered position. At this point the motor 23 is activated and, by means of the rod 22, acts on the structure 14, turning it by 90° about the axis C. At the end of this operation, the mattress 4 is orientated so that its longitudinal side is adjacent to the vertical rollers 35. After activating the jacks 25, 26 and 33, 34 again, thus raising the pads 27 and 28, the bar 31, and the plate 32, the longitudinal side is hemmed according to the above described procedures and so are the other sides, until the entire perimeter is completed. Advantageously, the rotation axis C of the structure 14 passes on the inside of the peripheral edge of the mattress proximate to the hem. In this manner, the hem at the corners of the mattress can follow a circular arc-like path that allows to form rounded corners. The substantial advantage of the device is provided by the rollers 2; since they are freely rotatable in both directions, they considerably reduce the resistance of the mattress to rotation. It is furthermore possible to interpose between the rollers 2 means that turn the mattress over, after one face thereof has been hemmed, in order to complete the hemming of the opposite face. For this purpose, the rollers 3 of the working table 2 are arranged so as to allow to arrange between them two frames 36 and 37 that can be raised by jacks (not shown, but easily imaginable) from a position in which they are co-planar with respect to the table 2 into an opposite position, in which they substantially form a V with respect to the table 2 (see figure 5). The frames 36 and 37 are constituted by respective arms 38 that are articulated within the roller table 3 and extend in the opposite directions A and B, respectively, between the rollers that form the various rows and are appropriately spaced so as to form a seat for accommodating the arms 38. Slats 39 extend at right angles from each arm 38 in opposite directions and are accommodated between the various rows of rollers 3. A mattress is turned over by placing it on one frame, for example on the frame 36, and by then rotating said frame about its fulcrum so that the mattress 4, after moving beyond the vertical position due to inertia, rests against the other frame 37, raised beforehand in front of the frame 36 so as to assume an inclined position. Once the mattress rests on the frame 37, said frame is lowered to deposit the mattress in overturned position on the roller surface 3. A preferred embodiment provides that the rollers 3 tangentially contact lower belts in engagement with driving pulleys, or that the rollers 3 have cylindrical interior bearing surfaces enclosing respective driving shafts, so that rotation of said pulleys or shafts causes rotation of said rollers. In this way it is possible to assist the advancement of the mattress during sewing and at the same time to permit the rotation of the rollers in the opposite direction when the mattress is swung around its rear corner. Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly such reference signs do not have any limiting effect on the interpretation of each element identified by way of example by such reference signs.

Claims: Device for turning a mattress (4) on a working table of a hemming machine (7), comprising: a vertically hinged structure (14) supported by a fixed frame above said working table and rotatable about a vertical axis (C) that passes at the stitching region of the hemming machine; means (20-23) for rotating said vertically hinged structure between two positions that are angularly offset by 90°; means (25-28) suitable to block said mattress against said working table being rigidly coupled to said vertically hinged structure; characterized in that said working table is constituted by free rollers (2) that lie at right angles with respect to the advancement direction of the mattress (A) and are arranged in parallel rows; said rollers being spaced so as to allow to arrange between them two articulated frames (36, 37) allowing to turn the mattress over on the working table; and in that said frames can be raised, by virtue of jacks (25,26,33,34), from a position in which they are co-planar with respect to said working table into an opposite position substantially forming a V with respect to said working table; said jacks (25,26,33,34) being actuated so as to turn the frame (36), on which the mattress (4) to be turned over has been placed, until said mattress rests on the opposite frame (37) that is standing by in an inclined position; said opposite frame (37) being then actuated so as to lower in order to deposit the mattress in overturned condition on the roller table. Device according to claim 1, characterized in that each frame (36, 37) comprises an arm (38) that is articulated to the working table and multiple slats (39) extending at right angles to said arm in opposite directions, said arm (38), in its lowered position, being suitable to fit between two adjacent rows of rollers, said slats (39) being suitable to fit between the rollers of said two adjacent rows. Device according to claim 1 or 2, characterized in that said working surface, on the side of the hemming machine (7), is delimited by a plurality of vertical free rollers (35) aligned in the direction (A) along which the mattress advances. Device according to claims 1-3, characterized in that the rollers are rotated in the advancing direction of the mattress by driving means in frictional engagement with said rollers.

Inventors: RESTA MARIO, RESTA ROBERTO, RESTA RODOLFO, RESTA, MARIO, RESTA, ROBERTO, RESTA, RODOLFO
Applicants: RESTA SRL, RESTA S.R.L.
Application year: 1995
Main classification: D05B11
IPC codes: D05B11