Abstract:
A monitor is provided for a bobbin thread on double thread lockstitch sewing machines. This is preferably a sewing machine with a rotating hook with a bobbin housing accommodating the lower thread reserve. The monitor includes a revolution sensor which sends a pulse per revolution of the main shaft of the machine to a microcomputer. An infrared laser light transmitter sends a detection beam directed toward a bobbin. The beam is reflected by the bobbin or by the roll of a residual thread length to a receiver and is sent by the latter to the microcomputer in the form of signals for processing, evaluation and/or forwarding. The microcomputer is adapted to compare the different signal patterns with a detection threshold (DS) to generate signals for controlling the sewing machine. A controllable power source is connected to the microcomputer for the occasional, stepwise reduction of the output of the infrared laser light transmitter. A bobbin can be inserted into the bobbin housing with at least two chambers separated from one another by a radially directed web. One chamber (the residual thread chamber) accommodates a residual thread length and the other chamber (the main chamber) accommodates the main thread length. The front surface of the web faces the infrared laser light transmitter as well as the outer surface of the flange of the bobbin. This outer surface is adjacent to the front surface, reflecting light, wherein the flange has openings for the detection beam.
Abstract:
A pre-wound bobbin for sewing, having a single flange or a pair of flanges, in which one flange of the bobbin comprises a magnetized material such that the flange magnetically adheres to the end wall of a steel bobbin case in which the bobbin is carried in a sewing machine. The flange is sized to provide a contact area with the end wall that, in relation to the magnetic strength of the magnetized material, achieves a magnetic attraction force exceeding the weight of the bobbin so that the bobbin is held in the bobbin case. The flange preferably is flexible.
Abstract:
The combination of a bobbin assembly and a support for the bobbin assembly. The bobbin assembly has a core around which a supply of thread can be wrapped and having a rotational axis, a first flange having first and second oppositely facing surfaces with the first surface bounding a storage space for thread wrapped around the core, and a magnetic element. The support has a third surface with a first metal material facing the second surface with the bobbin assembly operatively connected to the support and sufficiently close to the magnetic element so that a magnetic field is generated between the magnetic element and first metal material that tends to resists movement of the bobbin assembly relative to the support around the rotational axis of the core.
Abstract:
An automatic dual bobbin mechanism is provided. A housing containing two unique bobbin casings and bobbins therein oriented side-by-side with the sewing needle and thread passing between the bobbin casing pair replaces the convention single bobbin configuration. The bobbin pair acts in a tag-team operation whereby one bobbin supplies thread to be stitched into a fabric while the second bobbin is simultaneously filled with thread from an external source. When the first bobbin is emptied, the bobbin pair is rotated 180.degree. inside the housing. The second bobbin, now full, supplies thread for continued stitching while the first bobbin is refilled with thread supplied by the external source. The specially designed bobbins and bobbin casings allow for automatic rethreading of the empty bobbin and cutting of the bobbin thread from external source, thus eliminating the need to manually remove the empty bobbin and assembly, replace with a full bobbin and rethread.
Abstract:
Method of manufacturing a sewing machine bobbin having flanges at both ends, which is characterized by integrally welding bobbin parts by means of laser beam irradiation. Aluminum is suitable for bobbin material except having comparatively low melting point, which has conventionally made it difficult to use aluminum material for bobbin. Described is the method of welding alminum bobbin parts by means of laser beam irradiation, which is also available for welding other materials.
Abstract:
A sewing machine bobbin includes a mini-spool rotatably mounted on the bobbin for receiving a predetermined length at the inner end of the thread such that when the bobbin stops rotating, the mini-spool may continue to rotate to pay out a part of a predetermined length of thread in order to finish a stitching operation.
Abstract:
A cavity slightly larger and deeper than the bobbin it is adapted to receive is formed in one or both ends of the spool. A pair of diametrically opposing, bobbin-engaging tabs are formed on the cavity-bearing end and extend into the cavity. In addition, a pair of diametrically opposing notches are formed in the cavity-bearing end and open into the cavity so that the operator can reach under an outer portion of the bobbin and pry the bobbin out of the cavity.
Abstract:
A dispenser for storing and dispensing sewing machine bobbins, the device having flexible side walls which define an infeedoutfeed front opening for the bobbins as well as a rear slot through which an ejecting arm can be entered. The dispenser has an ejector mechanism which can be actuated to enter the slot and exert pressure on a bobbin to thrust it out of the infeed-outfeed opening against the light resistance offered by the flexible side walls.