CZ306915B6 - A looping sewing machine - Google Patents

Description

Technical field

A looping sewing machine comprising two needles to simultaneously sew both sides of the tab, the two needles being coupled to a common crank pin of the drive crank mechanism and each needle being associated with a hook.

BACKGROUND OF THE INVENTION

Belt loops, such as jeans trousers, are usually sewn on industrial so-called loop sewing machines. The technology of such sewing has its specifics, which is the preparation of the stock of the loops, its dividing into the necessary lengths, bending the ends of the strap, placing the loops on the waist, their fixation and sewing the ends of the loops.

Sewing of the loops was performed by sequential sewing of one and the other side of the tab, which was lengthy and inconvenient.

On modern industrial sewing machines, the sewing of the loops is usually carried out by two needles, which move simultaneously and simultaneously sew both ends of the loops. This requires that the spacing of the needles correspond to the length of the tabs currently sewn.

The hitching machines hitherto used essentially have a needle block connected to the needle bar drive in which two needles are clamped. At least one of the needles is displaceably positioned in the needle block relative to the other needle, which may be non-adjustable in the block.

When changing the production batch of garments that will use belt loops of a different length, it is usually necessary to change the relative position of the needles, i.e. to release one of the needles, move it to a new position and secure the needle in it.

This is inconvenient for the operator and the adjustment must be accurate, which of course increases the unproductive time of the manufacturing process.

It is an object of the present invention to overcome the shortcomings of the prior art, i.e. to substantially reduce said time losses and to ensure the exact positioning of the needles and their repeatability.

SUMMARY OF THE INVENTION

The object of the invention is achieved by a stitching machine according to the invention, characterized in that each needle is mounted on one needle bar and each needle bar is assigned one hook, the relative position of the needle bars and the hooks assigned to them is adjustable.

Further advantages and features are described in the dependent claims.

Clarification of the drawing

Exemplary embodiments of the device according to the invention are schematically shown in the drawing, in which Fig. 1 shows the arrangement of the drive and the positioning system of the needles and their respective hooks.

- 1 GB 306915 B6

DETAILED DESCRIPTION OF THE INVENTION

The upper part of the sewing machine forms the arm 1 of the sewing machine in which the needle bar and its drive are arranged. The arm together with the column with which it is rigidly connected and the machine lower housing 2 forms a rigid frame 10. The machine lower housing 2 is the base for the needle plate and the mechanisms associated therewith.

Fig. 1 shows an exemplary embodiment of the arm 1 and the lower housing 2 of the hand-held sewing machine according to the invention. A horizontal upper drive crankshaft 11 of a pair of needle rods 12, 13 is arranged in the arm 1. A long crank pin 112 is mounted between its cranks 111. In the vicinity of the cranks 111, connecting rods 113 are hinged to the crank pin 112, the other ends of which are rotatably connected to the needle shaft support shaft 114, 13. The shaft 114 is a connecting rod shaft. . The needle bars 12, 13 are non-rotatably coupled to the support shaft 114 by bushings 121, 131.

In the region of the support shaft 114, two linear guides 101 mounted in the machine frame 10 are arranged parallel to the axis of the crankshaft 11 and thus to the axis of the crank pin 112. A needle block 122 of a displaceably adjustable needle bar 12 is slidably mounted on the linear guides 101, in which the adjustable needle bar 12 is slidably mounted in the vertical guide bushings 123.

The needle needle housing 131 is displaceably mounted on the support shaft 114.

The needle block 122 is rigidly connected to the control rod 14 parallel to the drive shaft 11. The control rod 14 is provided with an external movement thread 141 which connects it to the adjusting shaft 15 of the adjustable needle bar 12 provided with an internal movement thread 151.

The upper drive crankshaft 11 is driven by a toothed belt transmission not shown by the main engine housed in the machine frame 10. The adjusting shaft 15 is driven by a stepper motor (not shown).

Known rotary hooks 21, not shown in greater detail, corresponding to the needle bars 12, 13, are arranged in the machine lower housing 2. The hook 21 associated with the adjustable needle bar 12 is housed in the movably adjustable block 22, the hook 21 associated with the fixed needle bar 13 is housed in the fixed block 23.

The movably adjustable block 22 is rigidly connected to the control bar 24 parallel to the arm shafts 11, 15. The control bar 24 is provided with an external movement thread 241, which is connected to the adjusting shaft 25 of the adjusting block 22. and is driven by a stepper motor (not shown) driving the adjusting shaft 15 of the adjustable needle bar 12.

The adjustable block 22 of the hook 21 is guided by the linear guide 102 during the adjustment.

The drive of the grippers 21 is mediated by a drive shaft 26 coupled to a toothed belt transmission with a main motor (not shown) driving the upper drive crankshaft 11.

Changing the position of the needle block 122 of the adjustable needle bar 12 and the adjustable block 22 of the hook 21 of the respective adjustable needle bar 12, and the drive of the needle bars 12, 13 and the hooks 21 is synchronous to the coupled drive motors.

The sewing machine is equipped with a control unit (not shown) for adjusting the width and length of the strap, the distance between the brackets and the number of stitches in the brackets, the automatic thread cut, and the strap loading mechanism according to the desired strap length. In addition, the device according to the invention makes it possible to automatically adjust the relative position of the needle bars. The operator adjusts these parameters, for example, using the touch screen.

-2GB 306915 B6

It is an object of the invention that each needle is mounted on one needle bar and each needle bar is associated with a single hook, wherein the relative position of the needle bars and their associated hooks is adjustable. This solution can also be achieved in that both needle bars and their associated hooks are adjustable. Such a solution is obvious to the person skilled in the art and is a matter of ordinary craft skill.

Claims (6)

PATENT CLAIMS A stitching machine comprising two needles to simultaneously sew both sides of the tab, wherein both needles are coupled to a common crank pin (112) of the drive crank mechanism and each needle is associated with a gripper (21), characterized in that each needle is mounted on One hook (21) is associated with each needle bar (12, 13) and each needle bar (12, 13), the relative position of the needle bars (12, 13) and the associated hooks (21) being adjustable. Stitching machine according to claim 1, characterized in that one needle bar (13) and its associated hook (21) have a fixed position of their sewing axis and the other needle bar (12) with its associated hook (21) is coupled to an adjusting mechanism coupled to the sewing machine control. Stitching machine according to claim 1, characterized in that the needle bars (12, 13) are mounted on a common support shaft (114) forming the connecting rod pin of the drive crank mechanism, the fixed needle bar (13) being fixedly connected to the support shaft. (114), wherein the adjustable needle bar (12) is non-rotatably and axially aligned with the support shaft (114), and the adjustable needle bar (12) is slidably mounted in the needle block in the direction of its sewing movement (114) 122) guided by a linear guide (101) in a direction perpendicular to the sewing direction of the needle and its associated gripper (21) is housed in an adjustable block (22) guided by a linear guide (102) parallel to the linear guide (101). Stitching machine according to claim 3, characterized in that an adjusting rod (14) is connected to the needle block (122) by means of a threaded movement to the motor-driven adjusting shaft (15), the associated adjusting block (22) of the hook (14). 21) an adjusting rod (24) connected by a movement thread to a motor driven adjusting shaft (25) is fastened. Stitching machine according to claim 4, characterized in that the motor drive of the adjusting shaft (15) of the needle block (122) and the adjusting shaft (25) of the adjusting block (22) of the hook (21) is a common stepper motor. Stitching machine according to any one of the preceding claims, characterized in that the needle crank drive mechanism (12, 13) and the hook gripper drive (21) are coupled to a common drive motor.