Sewing – Elements – Thread guiding or handling
Reexamination Certificate
2001-09-25
2002-10-22
Izaguirre, Ismael (Department: 3765)
Sewing
Elements
Thread guiding or handling
C112S293000
Reexamination Certificate
active
06467419
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of Invention
The invention relates to an upper thread cassette and an upper thread changing device. More particularly, it relates to an upper thread cassette and an upper thread changing device that facilitate the performance of upper thread changing operations, such as when a color of an upper thread is changed during sewing operations.
2. Description of Related Art
Before starting sewing operations with a conventional sewing machine, some preparation is required. For example, a thread spool having a thread of a desirable color wound therearound is set to the sewing machine. An upper thread is pulled out of the thread spool and threaded on some mechanisms of the sewing machine, such as a thread guide, a thread tension guide, and a thread take-up. The upper thread is then passed through a needle eye. Especially when embroidering operations are performed for an embroidery pattern that requires a plurality of threads of different colors, an operator has to repeatedly perform the troublesome operations of setting thread spools on the sewing machine and threading upper threads on the above-described mechanisms of the sewing machine, as well as threading a needle, every time the embroidering operations with one color of the upper thread is finished and the color of the upper thread is changed to another.
In recent years, thread connecting devices, such as those described in U.S. Pat. No. 4,579,615 and Japanese Laid-Open Patent Publication No. 9-302571, that connect an end of a thread wound around one thread spool selected from a plurality of thread spools and an end of a thread threaded onto a sewing machine, are put into practical use. In the thread connecting device disclosed in U.S. Pat. No. 4,579,615, a thread connecting means cuts an upper thread, and holds an end of the upper thread belonging to or threaded onto a sewing machine and an end of an upper thread of a desirable color belonging to or wound around a thread spool, at a predetermined position. The thread connecting means connects the thread ends, through the medium of a connecting thread, by melting.
In a thread connecting device disclosed in Japanese Laid-Open Patent Publication No. 9-302571, vacuuming with a tube is started so as to move a thread clamp and a wiper toward a needle. After an end of an upper thread is clamped between an inner wall of the thread clamp and a vacuum ball, a hook and the thread clamp are moved by a cylinder toward an index. The vacuuming is stopped to return the thread clamp and the wiper to their original positions.
The clamped thread end is moved toward gears and the upper thread is drawn. Thereafter, the hook capturing the thread retracts. The distance between a pair of the gears is closed by the cylinder. An electric current is passed through a heating wire of a thread cutter and the upper thread is cut. Then, a knotter is moved by the cylinder to a thread knotting position. After the cylinder closes a tension disc, the thread knotting operations are performed by the cylinder.
In the conventional thread connecting device that employs thread spools, an upper thread is often pulled out of a thread spool to be longer than it needs to be, due to a reaction force of the thread wound around the thread spool (the force resulting as the thread tries to separate from the thread spool), resulting in slack in the upper thread in a path of the upper thread leading from the thread spool to a thread guide. Such slack causes the upper thread to get twisted, entangled, or overlapped, which leads to non-uniform upper thread tension. Consequently, the upper thread and an under thread are not properly tensioned, resulting in poor-looking stitches. In worse cases, the thread or a needle is broken.
As disclosed in Japanese Patent No.2650261, such an upper thread cassette containing an upper thread that applies uniform tension to the upper thread to be drawn and prevents the upper thread from being entangled is proposed and put into practical use. The upper thread cassette disclosed in Japanese Patent No. 2650261 includes a cassette body, a thread accommodating hole, an upper thread wound around an upper thread bobbin which is to be accommodated in the thread accommodating hole, an “L”-shaped plate spring, a pin, and a plurality of notches. While tension is applied to the upper thread by holding the upper thread between the plate spring and the pin, the upper thread is pulled through a thread pull-out hole. The tension applied to the upper thread is adjustable by engaging a protrusion of the plate spring with a different one of the notches.
Problems with the thread connecting devices disclosed in U.S. Pat. No. 4,579,615 and Japanese Laid-Open Patent Publication No. 9-302571, are they are expensive and they consist of large-sized devices having complicated structures.
In the conventional upper thread cassette disclosed in Japanese Patent No. 2650261, when a color of an upper thread is changed to a different color during sewing operations, the upper thread is cut and the upper thread cassette has to be removed from the sewing machine. Then, another upper thread cassette containing an upper thread of desirable color is set to the sewing machine, followed by the operations of threading the upper thread on a thread guide, a thread tension guide, and a thread take-up, and threading a needle. Thus, changes of upper thread colors require the troublesome operations.
In addition, when the upper thread cassette is not mounted, the upper thread needs to protrude, after cutting, from the upper thread cassette by an appropriate length, as a preparation for the next use (for the cassette remounting), so that a pressing force exerted between the plate spring and the pin needs to be set to high, to prevent the upper thread in the cassette from being excessively pulled out. When the upper thread cassette is mounted, the upper thread necessary for the sewing operations with the sewing machine has to be pulled from the upper thread cassette, so that the pressing force exerted between the plate spring and the pin needs to be set to low.
SUMMARY OF THE INVENTION
The invention provides an upper thread cassette and an upper thread changing device that facilitate upper thread changing operations to be performed, such as when a color of an upper thread is changed during sewing operations, as well as the upper thread changing device having a simplified structure so as to achieve a reduction in the size of the device.
According to one aspect of the invention, there is provided an upper thread cassette that contains an upper thread for use in sewing. The upper thread cassette may include a cassette member including a cassette body and a cassette cover that opens or closes the cassette body, a thread wound member mounting part that mounts thereon a thread wound member winding the upper thread therearound and is provided inside the cassette member, and a cutting mechanism that cuts the upper thread supplied from the thread wound member mounted on the thread wound member mounting part.
In the upper thread cassette of the invention, the thread wound member winding the upper thread therearound may be mounted on the thread wound member mounting part provided inside the cassette member. From the upper thread cassette, an end of the upper thread may be pulled out. Then, the cassette cover may be closed. The upper thread supplied from the thread wound member mounted on the thread wound member mounting part may be cut by the cutting mechanism. With the above-described structures, a pair of scissors or another cutter does not have to be prepared to cut the upper thread. Therefore, thread cutting operations may be improved.
The upper thread cassette may further include a thread end holding member that holds an end of the upper thread cut by the cutting mechanism. Because the cut upper thread may be held by the thread end holding member, an end of the upper thread does not have to be pulled out of the upper thread cassette every time the upper thread cassette is mounted. Consequently, the operation of changing
Brother Kogyo Kabushiki Kaisha
Izaguirre Ismael
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