Sewing – Stitch forming – Multiple needle
Reexamination Certificate
1999-09-30
2001-01-09
Izaguirre, Ismael (Department: 3741)
Sewing
Stitch forming
Multiple needle
Reexamination Certificate
active
06170415
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of Invention
The invention relates to a sewing machine having multiple needle bars and needle thread take-ups which are used in a sequential manner enabling creation of a sewing pattern in which multiple colors are used.
2. Description of Related Art
Conventionally, there are sewing machines having a plurality of needle bars and needle thread take-ups on a machine head, which are changed one by one successively to continue a sewing operation. These examples are indicated in Japanese laid-open Patent Publication Nos. 9-38367 and 9-75569.
When one such sewing machine is used for creating a colorful sewing pattern stitched with various color threads, it can continue a sewing operation while automatically changing needles without interruption so that operator does not have to change threads.
However, speeding up of the sewing machine has been recently tried to produce sewing operations with high efficiency. For an embroidery machine, for example, the speed of the upper shaft is limited to about 1,000 to 1,200 rpm, but it is expected to be higher.
Where multiple needle bars are installed in a sewing machine, all needle positions are not aligned because of slight differences, such as machining accuracy and assembly accuracy. As a result, a relative position between a needle attached to the bottom of a needle bar and a rotary hook often varies for each needle. Therefore stitching quality deteriorates when the machine is in operation at a higher speed.
SUMMARY OF THE INVENTION
The invention was made in view of such problems, and it is therefore an object of the invention to provide a sewing machine with multiple needles that can maintain sewing quality during high speed sewing by enabling the adjustment of the needles individually to eliminate variations therebetween.
To accomplish the object, the invention provides a sewing machine with multiple needles having a plurality of needle bars that are arranged in a horizontal line, a box holding the needle bars, a needle bar driving part that allows each needle bar to move up and down, a body frame including the needle bar driving parts, and a box driving part that moves the box right and left relative to the body frame, to transmit the driving force of a needle bar driving part only to a desired needle bar, and a needle position adjusting part provided in each needle bar, wherein a relative position between a needle that is attached to the bottom of the needle bar and a rotary hook that receives both the needle and an upper thread put through the needle can be adjusted.
In the sewing machine with multiple needles, a relative position between a needle attached to the end of the needle bar and a rotary hook can be adjusted for each needle bar.
Therefore, according to the sewing machine with multiple needles, the position of an individual needle varies from that of other needle bars because of variations in machining and assembly accuracy, but it can be adjusted using the needle position adjusting part. Moreover, the position of the needle can be adjusted for each needle bar without affecting the remaining needle bars. Accordingly, sewing quality can be assured even during high-speed sewing.
In a preferred form of the invention, the needle position adjusting parts are provided at the box so that they can be individually adjusted right and left. They correspond to needle bar guides that hold each needle bar vertically.
Therefore, according to the sewing machine with multiple needles, the positional deviation between a needle and the rotary hook, which occurs in the right and left direction, can be adjusted for each needle.
In another preferred form of the invention, the needle position adjusting parts are provided at the box so that they can be individually adjusted back and forth. They correspond to needle bar guides that hold each needle bar vertically. Therefore, according to the sewing machine with multiple needles, the positional deviation between a needle and rotary hook can be adjusted on each needle in the back and forth direction.
In a further preferred form of the invention, the needle bar guide, in the shape of the letter “c”, holds the needle bar vertically by passing it through upper and lower holes of the needle bar guide, and comprises a projection provided horizontally in the opposite direction to the side through which the needle bar passes. The box has a hole to be engaged with the projection. The projection and the hole are used to adjust the relative position between the needle and the rotary hook. By adjusting the amount and angle of how much the projection is fit into the hole, the relative position between the needle and the rotary hook can be adjusted.
In the sewing machine with multiple needles as arranged above, the needle bar guide can be moved back and forth for adjustment by changing the amount and angle of how much the projection is fit into the hole. The tip of the needle bar can be moved right or left by turning the projection in the hole.
In another preferred form of the invention, the needle position adjusting part is provided at the bottom of the needle bar, and further corresponds to a needle supporting part including a hole for the needle to be inserted, to hold the needle at an eccentric position from the axis of the needle bar.
In the sewing machine with multiple needles, the relative position between the axis of the needle bar and the axis of the needle will be changed when the needle supporting part is rotated.
Therefore, in the sewing machine with multiple needles, the positional deviation between the needle and the rotary hook can be adjusted within a correctable range by rotating the needle supporting member.
In a further preferred form of the invention, a plurality of plates are each provided with a hole for each needle bar at least at the box. The holes are arranged in a horizontal line with the same interval as the needle bars, and provide for a pin that can be inserted into a hole in one of the plates. The plates can be individually moved from side to side for adjusting the respective positions.
In the sewing machine with multiple needles, the needle supporting part is rotated to adjust the relative position between the needle and the rotary hook in the back and forth direction, and then a plate corresponding to the needle is moved right or left to correct the resultant right and left positional deviation.
In this form of the invention, the needle supporting part may be combined with not only what is rotated but also with what adjusts the back and forth position of the needle. Otherwise, the needle supporting part may be rotated to adjust the relative position between the needle and the rotary hook in the back and forth direction, and then the needle bar guide may be moved right or left to correct the resultant right and left positional deviation. Therefore, according to the sewing machine with multiple needles, the positional deviation occurring in the right and left direction can be adjusted.
According to the sewing machine with multiple needles described above, the relative position between the needle and the rotary hook can be adjusted at the needle position adjusting part, however, the positional deviation may occur because of the deviation of the position of the box, in addition to machining accuracy of the needle bar driving part and the assembly accuracy of the needle bar.
In view of the above, in another preferred form of the invention, the sewing machine with multiple needles of the invention further comprises a box position adjusting part that adjusts the back and forth position of the box in relation to the body frame. When the box is out of place in the back and forth direction, it can be adjusted at the box adjusting part. If the relative position between each needle and the rotary hook is not appropriate after the position of the box is adjusted, the needle position adjusting part may be used. When the positional deviation in the back and forth direction common to all needles is adjusted in advance using the box position adjusting part, adjust
Inoue Kazushi
Nakano Motonari
Nozaki Yoshihisa
Ori Hitomi
Brother Kogyo Kabushiki Kaisha
Izaguirre Ismael
Oliff & Berridg,e PLC
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