Pre-folding device for tapes used to feed tape edge machines, especially for mattresses

Abstract

 The present invention refers to a pre-folding device for tapes used to feed tape edge machines, especially for mattresses, which accepts any size of tapes and includes a support block that guides a sliding frame formed of a central stem and a fork designed to create a semicircle arch-shaped slot, whose linear development can be varied by sliding the frame with a threaded actuation bar.

Description

[0001] The present patent application for industrial invention refers to a pre-folding device for tapes used to feed tape edge machines, especially for mattresses. Tape edge machines are sewing machines used to apply a C-folded tape along the mattress edges to embrace the borders of the fabric on the upper and lower edge of the mattress.

[0002] As it is known, bed mattresses have an external lining formed of two rectangular pieces of fabric, i.e. an upper fabric and a lower fabric, and a long perimeter band having the same height as the mattress thickness, whose longitudinal edges are sewn with the two pieces of fabric.

[0003] The seam is normally finished with a folded tape sewn externally on the edges, which are therefore hidden and contained inside the tape.

[0004] The sewing machines used for this operation are technically defined as tape edge machines, and are characterized in that they are provided with a special element located near the needle and used to convey the folded tape towards the needle.

[0005] The tape is previously folded by means of a special device situated upstream and fed directly by the tape reel.

[0006] The tape enters the pre-folding device in extended position and is delivered with C-shape in order to receive the edges of the fabric on the mattress borders; once the tape has been sewn on the upper side of the mattress, the mattress is turned over in order to repeat the operation on the lower side of the mattress.

[0007] The pre-folding devices that are currently known and used in the market need to be changed according to the height of the tape, since they are dimensioned and shaped for a specific height of the tape.

[0008] In other words, the said devices are not versatile in use, being specifically designed to fold tape with a specific height.

[0009] Inconveniences are evident, since the pre-folding device needs to be changed every time the size of the tape changes, thus wasting time and labour.

[0010] In addition to limited application, the known pre-folding devices are also impaired by the fact that they depend on the type of fabric; in spite of the same height of the tape, they sometimes need to be changed because of the different type of fabric.

[0011] The purpose of the present invention is to find a solution to the aforementioned inconveniences with a new pre-folding device for tape edge machines capable of being adjusted to operate with any size of tape.

[0012] Another purpose of the present invention is to realize a new pre-folding device for tape edge machines, characterized by micrometric adjustment in order to eliminate the negative consequences caused by different types of fabric with the same size.

[0013] The device of the invention comprises a support block that guides a sliding frame formed of a central stem and a fork protruding from a pedestal.

[0014] More precisely, the central stem and the parallel sections of the fork are inserted into the block in such a way that the pedestal remains on the back of the block, from which the point of the stem and the arch-shaped ending section of the fork protrude from the front.

[0015] The slot used to insert and pre-fold the tape coincides with the C-shaped gap that remains between the point of the central stem and the arch-shaped section of the fork.

[0016] The linear development of the C-shaped slot can be increased or decreased by moving the frame forward or backward inside the support block. The support block is provided with a flange with a hole used to insert and guide a threaded bar screwed in a threaded hole located in central position on the pedestal and axially inserted inside the stem, being provided with a longitudinal section of an axial passage used to house the threaded bar, whose rotation may be determined by means of an actuation knob formed of a parallel pair of circular dishes, respectively located on the front and back of the flange.

[0017] The threading of the bar has a very small pitch, thus allowing for micrometric adjustment of the frame travel.

[0018] For major clarity the description of the device of the invention continues with reference to the enclosed drawings, which are intended for purposes of illustration only and not in a limiting sense, whereby:

• Figs. 1 and 2 are an axonometric view of the device of the invention seen from opposite sides;
• Fig. 3 is an axonometric view of the device of the invention in operational conditions.

[0019] With reference to Fig. 3, the device of the invention (1) is designed to be mounted in tape edge machines used to sew a finishing tape (N) fed from a reel (B) on any type of manufacture, especially mattresses.

[0020] The device (1) is designed to pre-fold the tape (N) according to an open C-shape, it being then closed and definitely tightened by a special compression element located near the sewing needle downstream the pre-folding device (1).

[0021] The device (1) comprises a prismatic block (2) laterally provided with a shelf (3) with a slot (4) used to insert the fixing screws of the device (1) above the work plane (P) of the sewing machine, not illustrated in Fig. 3.

[0022] With reference to Figs. 1 and 2, the block (2) supports and guides a sliding frame (5) formed of a circular pedestal (5a), from which a central stem (5b) and a fork (5c) frontally protrude, whose sections run on parallel opposite sides with respect to the central stem (5b), with the rounded point (5d) surrounded by the ending section (5e) of the fork, with C-shape as a semicircle arch.

[0023] The block (2) is provided with a pair of through holes (2a) where the two sections of the fork (5c) are inserted and slide, and with a third hole (2b) in intermediate position between the two holes (2a) where the central stem (5b) is inserted and slides.

[0024] A projecting rod (7) is fixed with screws (6) on one side of the block (2), ending with a transversal flange (8) laying on a parallel plane behind the pedestal (5a), which has a central threaded hole (9) where a threaded bar (10) is screwed. After passing through the hole (9), a rear longitudinal section of the threaded bar (10) is inserted through an axial conduit inside the stem (5b).

[0025] The rear end of the bar (10) is inserted through a hole on the flange (8) and supports an actuation knob (11) formed of a pair of parallel circular dishes with knurled border, respectively fixed on the front and back of the flange (8), which prevents the forward or backward sliding of the knob (11) during rotation, thus consequently and indirectly causing the forward or backward movement of the sliding frame (5) with respect to the block (2).

[0026] The travel of the frame (5) allows for using the device (1) with tapes having a different height, which are inserted into the C-shaped slot (12) comprised between the rounded point (5d) of the central stem (5b) and the arch-shaped section (5e) of the fork (5c).

[0027] The linear development of the slot (12) can be adjusted by sliding the frame (5) according to the height of the tape (N) to be folded.

[0028] The threading of the bar (10) has a very small pitch, thus allowing for micrometric adjustment of the frame travel.

[0029] Finally, it must be noted that the external side of the rod (7) is provided with a graduated scale (7a) and the border of the pedestal (5a) is provided with a mark (13) used as reference index for the scale (7a) that shows the most typical heights used in tape edge machines.

[0030] According to a preferred embodiment of the present invention, an eye (14) is externally provided in the arch-shaped section (5e) of the fork (5c) to pass and guide the reinforcement string (C) that is sometimes inserted and sewn inside the pre-folded tape (N) in order to make the tape stronger and improve the final finish.

[0031] Numeral (15) refers to the head of a screw used to adjust the compression pressure of a friction pad contained in a suitable housing provided in the prismatic block (2) that interferes with one of the two sections of the fork (5c).

Claims

1. Pre-folding device for tapes used in tape edge machines, especially for mattresses, characterized in that it comprises:

- a prismatic block (2) that supports and guides a sliding frame (5) formed of a circular pedestal (5a), from which a central stem (5b) and a fork (5c) frontally protrude, whose sections run on parallel opposite sites with respect to the central stem (5b), with the rounded point (5d) surrounded by the semicircle arch-shaped ending section (5e) of the fork.

- a projecting rod (7) that projects on the back of the block (2) and ends with a transversal flange (8) laying on a parallel plane behind the pedestal (5a), which has a central threaded hole (9);

- a threaded bar (10) that is screwed in the hole (9), with a rear longitudinal section of the bar (10) inserted in an axial passage inside the stem (5b);

- a knob (11) applied at the rear end of the bar (10) and formed of a pair of parallel circular dishes with knurled border, respectively fixed on the front and back of the flange (8), which has a hole for the insertion of the bar (10).

2. Pre-folding device for tapes used in tape edge machines, especially for mattresses, as defined in the above claim, characterized in that the threading of the bar (10) has a very small pitch to allow for micrometric travel adjustment of the frame (5).

3. Pre-folding device for tapes used in tape edge machines, especially for mattresses, as defined in the above claims, characterized in that
the external side of the rod (7) is provided with a graduated scale (7a) and the border of the pedestal (5a) is provided with a mark (13) used as reference index for the scale (7a).

4. Pre-folding device for tapes used in tape edge machines, especially for mattresses, as defined in the above claims, characterised in that it comprises an eye (13) in external position on the arch-shaped section (5e) of the fork (5c) used to pass and guide a string (C).

Drawing